Department of Electrical & Computer Engineering
Annual Research Report
Department of Electrical and Computer Engineering
Polytechnic University
Five Metrotech Center
Brooklyn, NY 11201
Phone: (718) 260 3590
Fax:
(718) 260 3906
http://eeweb.poly.edu
LAST UPDATED 2/16/2016
The Department of Electrical and Computer Engineering is home
to two research centers:
CATT
The Center for Advanced Technology in Telecommunications and
Distributed Information Systems (CATT) is a research and
education group at Polytechnic University, long-recognized as one
of the best engineering schools in the country.
Our researchers are leaders in the fields of electrical engineering and computer
science. The Center also draws on the expertise of key researchers at Columbia
University.
Companies that partner with CATT in joint research gain access to state-of-the-art
facilities and a team of experts who understand how to turn technological breakthroughs
into commercially viable products and services.
The Center Director is Prof. Shivendra Panwar.
For more information, please refer to http://catt.poly.edu/index.html.
WICAT
The Wireless Internet Center of Advanced Technology
(WICAT) is a joint research center created by
Columbia and Polytechnic University. As a future
Industry/University Cooperative Research Center
member, WICAT is partnered with companies and
organizations from across the industry, from
telecommunications and manufacturing giants to
wireless customers and small start-up firms.
The I/UCRC program helps industry and academia come together to overcome practical
research challenges. For WICAT, this means that companies who become our partners
help to direct future areas of wireless study and gain first access to new research. This
research is aimed at anticipating not only their needs, but also the needs of their clients,
suppliers and the industry as a whole.
WICAT’s goal is to be a catalyst for wireless innovation, and to help foster an
ecosystem that partners vendors, service providers, government agencies, research
initiatives, end-users, and small companies and start-ups. Our mission is both to
facilitate communication between these partners and to provide them with a pool of
research that can be applied to practical problems in the wireless industry.
The Center Directors are Profs. David Goodman (Poly) and Andrew Campbell
(Columbia). For more information, please refer to http://www.poly.edu/wicat/.
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This report is a collection of ongoing research
projects undertaken by ECE faculty in the areas of
I. Fields and Waves
II. Systems, Control and Signal Processing
III. Telecommunications and Wireless
IV. VLSI, Electronics and Power
3
List of Contributors
Henry Bertoni
hbertoni@duke.poly.edu
Frank Cassara
cassara@rama.poly.edu
Jonathan Chao
chao@poly.edu
Dariusz Czarkowski
dcz@pl.poly.edu
Nirod Das
ndas@photon.poly.edu
Elza Erkip
elza@poly.edu
David J. Goodman
goodman@duke.poly.edu
Zhong-Ping Jiang
zjiang@control.poly.edu
Ramesh Karri
ramesh@india.poly.edu
Farshad Khorrami
khorrami@smart.poly.edu
Spencer Kuo
spkuo@rama.poly.edu
Yong Liu
yongliu@poly.edu
I-Tai Lu
itailu@rama.poly.edu
Shivendra S. Panwar
panwar@catt.poly.edu
S. Unnikrishna Pillai
pillai@hora.poly.edu
Ivan W. Selesnick
selesi@taco.poly.edu
Andrej Stefanov
stefanov@poly.edu
Peter Voltz
voltz@rama.poly.edu
Yao Wang
yao@vision.poly.edu
Zivan Zabar
zzabar@poly.edu
4
Table of Contents
I. Fields and Waves ............................................................................. 8
Computational Electromagnetics: Theory and Techniques for Advanced Electromagnetics
Modeling ..................................................................................................................................9
Artificial Materials for Electromagnetics Applications ........................................................... 10
Multilayered RF Integrated Circuits and Antennas............................................................... 11
Wave-Plasma Interactions in Artificial Modification of the Ionosphere and Magnetosphere
by Powerful Radio Waves .................................................................................................... 12
A Microwave-augmented Plasma Torch as an Igniter/Fuel Injector in a Scramjet Engine .. 14
The Plasma Mitigation of the Shock Waves in Supersonic/Hypersonic Flights ................... 16
A Portable Arc-seeded Microwave Plasma Torch and Its Application for Decontamination of
Biological Warfare Agents .................................................................................................... 18
II. Systems, Control and Signal Processing ....................................... 20
Analysis and Control of Communication Networks .............................................................. 21
Stability of Nonlinear Dynamical Systems ............................................................................ 23
Applied Nonlinear Control..................................................................................................... 24
Robust Adaptive Nonlinear Control System Designs........................................................... 25
Development of Hardware/Software Architecture for Autonomous Unmanned Vehicles.... 27
Nonlinear Control for Electric Motors.................................................................................... 29
Development of an Ultra-Accurate High-Speed Six DOF Manipulator and Other Robotic
Systems ................................................................................................................................ 31
Decentralized Control of Nonlinear Large-Scale Interconnected Systems .......................... 33
Joint Transmitter-Receiver Design for Interference and Noise Suppression ....................... 34
Video Coding using a 3-D Motion-Selective Wavelet Transform ......................................... 36
The Design of Specialized Wavelet Transforms .................................................................. 37
Non-Gaussian Probability Models for Wavelet-Based Denoising ........................................ 39
A Motion-Selective 3-D Wavelet Transform for Enhancement of Imagery in Video Data ... 40
Wavelet Processing for Positron Emission Tomography ..................................................... 41
On-Demand P2P Video Streaming System ......................................................................... 42
Video Transport over Wireless Ad Hoc Networks ................................................................ 44
5
III. Telecommunications and Wireless ................................................. 46
OFDM Wireless LAN ............................................................................................................ 47
Cyber Security Processor (CYSEP) ..................................................................................... 48
Multi-Stage Buffered Packet Switches ................................................................................. 50
Cooperative Wireless Communications: Fundamental Principles ....................................... 52
Cooperative Coding for Wireless Networks.......................................................................... 54
Cooperative Source and Channel Coding............................................................................ 55
Cooperative Regions and Partner Choice in Coded Cooperative Systems ........................ 56
Preamble and Feedback Design in Multiple Antenna Systems ........................................... 57
Radio Resource Management in Cellular Communications ................................................ 58
Capacity of a CDMA Base Station Receiving Real-Time Media Signals and Data Files .... 60
Power Efficient Multimedia Wireless Communications ........................................................ 61
Network X-ities: Foundations and Applications .................................................................... 63
Analysis and Design of Overlay and Peer-Peer Networks................................................... 65
Network Measurement and Monitoring ................................................................................ 67
Sensor Management ............................................................................................................ 69
Wireless Geolocation............................................................................................................ 70
Fading Channel Prediction with Multipath Based Modeling ................................................. 71
Designing Medium Access Control for Cooperative Networks ............................................ 72
Performance Evaluation of IEEE the 802.11e Enhanced Distributed Channel Access
(EDCA) ................................................................................................................................ 74
High Performance Stable Packet Switches.......................................................................... 76
Joint Source and Channel Coding for MIMO Video Communications ................................. 78
Space-Time Coding.............................................................................................................. 79
Coded Cooperative OFDM Systems.................................................................................... 80
Indoor localization of WI-FI Tags .......................................................................................... 81
Capacity of MIMO systems with Antenna Subset Selection ................................................ 82
IV. VLSI, Electronics and Power .......................................................... 83
Mitigation of Voltage Disturbances Caused by Nonlinear Electrical Massive Loads ........... 84
Development of a Unit Substation Demand Estimator......................................................... 85
High Speed Cryptographic Architectures ............................................................................. 86
Secure Built-In-Self-Test (BIST) Architecture ....................................................................... 88
Fault Attack Resistant High Speed Crypto Architectures ..................................................... 89
6
Fault Tolerant Nanoscale Systems ...................................................................................... 90
Dept. of ECE - Grants and Contracts ................................................................................... 92
7
I. Fields and Waves
8
Computational Electromagnetics: Theory and
Techniques for Advanced Electromagnetics
Modeling
Our current research on computational electromagnetics is directed towards new methods
and simulation environment for next generation of applications. The objective is to allow fast
and efficient electromagnetic simulation of devices and systems of increasing size,
complexity and functionality. Not only one-time electromagnetic simulation, but also
computation-intensive iterations needed for design optimization of complex electronic
systems should be feasible with minimal efforts and computation time. Further, the basic
modeling approach and simulation engine should smoothly adapt to a modern evolutionary
design process. Simulation techniques in common use today do not properly address such
issues. Therefore, as the complexity of modern electronic systems grows rapidly, the scopes
of existing simulation methods are becoming severely limited, often prohibitive.
Investigation of fresh new approaches, having potentials of orders of magnitude
improvement over the conventional techniques, is warranted.
The research is targeted for modeling and design of complex RFIC chips and packages,
mixed packages or systems with digital, analog and RF circuits, large phased-array antennas,
and satellite communication systems.
Other target applications include complex
communication environment with scattering elements that are close or far apart, with
arbitrary size and shape. This includes, for example, simulation of micro or pico-cellular
environment, smart-antenna array designs in a near-field scattering environment, and aircraft
antenna systems.
Participating Faculty: Nirod K. Das (ndas@photon.poly.edu)
[1] N. K. Das and D. M. Pozar, Generalized CAD Models for Multilayer Printed Antennas
and Arrays, thematic issue on Computational Electromagnetics, Computer Physics
Communications, North Holland Physics Publishing, Ed. L. Safai, pp.393-440, November
1991.
[2] B. McCabe, Efficient Numerical/Analytical Modeling of Quasi-Planar Structures, PhD
Thesis, Department of Electrical and Computer Engineering, Polytechnic University,
January 2004.
[3] B. McCabe and N. K. Das, Slot Antenna Element with a Metal Back-Plate, Surrounded
by Shorting Posts to Suppress Parallel-Plate Mode Excitation: A New Theory and Design
Characteristics, IEEE Transactions on Microwave Theory and Techniques, to be published.
9
Artificial Materials for Electromagnetics
Applications
Performance of conventional electromagnetic devices and systems, such as microwave
circuits, IC packaging structures, antenna elements, and phased array radars, are limited by
many fundamental constraints dictated by the electromagnetic theory. These include, for
example, minimum size or compactness of devices, maximum radiation or guided-wave
efficiency in a given environment, minimum cross-polarization level of radiation from a
particular antenna, maximum directivity or gain of antenna elements fabricated in a given
space, or maximum practical range of steering angle of an electronically-controlled phased
array radar. The above theoretical constraints assume the operational environment to be free
space or conventional material media, in which practical designs currently in use normally
operate. However, it may be possible to overcome some of the basic electromagnetic
constraints for advanced applications by employing “non-conventional” materials. Such
new materials may not be available in natural form. But, materials could be artificially
fabricated in different forms, for example by reinforcing conventional dielectric or magnetic
materials with metal or dielectric wires in different shapes and orientations. Further, the
reinforcement may be finely distributed making the material look almost uniform, or the
reinforcement may be relatively non-uniform in nature in the form of periodic or quasiperiodic perturbations.
We are currently investigating simple artificial materials that may be implemented using
periodic reinforcement of simple metallic structures in a dielectric environment. Simple
metal-reinforcements are probably the easiest to manufacture, and may be implemented in a
single or multilayer form by photo-etching or microelectronic fabrication process. Such a
material is used as the primary substrate or as a secondary layer in the form of a
radome/superstrate or backplane support for a printed antenna element or a printed-circuit
packaging structure. Of particular importance is development of new techniques for
electromagnetic modeling of antennas and circuits operating in such material environment.
Participating Faculty: Nirod K. Das (ndas@photon.poly.edu)
[1] A. K. Mohanty and N. K. Das, “Infinite Array of Printed Dipoles Integrated with a
Printed Strip Grating for Suppression of Cross-Polar Radiation, Part I: Rigorous Analysis
and Part II: An Idealized Unidirectionally Conducting Screen Approximation,” IEEE
Transactions on Antennas and Propagation, pp.960-981, June 1997.
[2] J-W Wang, “Multilayer Printed Antennas with Biaxial Anisotropic Dielectric Substrates:
General Analysis and Case Studies,” PhD Thesis, Department of Electrical and Computer
Engineering, Polytechnic University, January 2002.
10
Multilayered RF Integrated Circuits and
Antennas
Integrated circuits performing diverse functions, such as radio-frequency electronics,
radiating antennas, digital processing, various control and power functions, as well as optical
processing and interconnects, are seen as the trend of the future in order to meet rapidly
growing demands for communication and data processing. All such diverse functions would
have to be integrated sharing a reasonable-sized physical chip, while it may be desirable that
separate functions are implemented in a modular manner requiring different material
substrates or technology for optimal functioning. Integration in a multilayered architecture is
most attractive in order to meet technological, economic as well as topological and space
constraints involved in implementation of such multi-functional chips. We have been
developing basic technology and design concepts in order to implement RF, antennas and
interconnect functions in such a multilayer architecture.
Some fundamental and design considerations include: (i) electromagnetic connectivity
across independent layers or between independent functions such as an antenna element and
its feeding electronics, (ii) new types of transmission lines or waveguides that are best suited
for operation in a multilayer environment, (iii) possible new phenomena that may be unique
to such multilayered structures, (iv) new circuits and components that may take advantage of
this multilayered environment to implement advanced operations not easily possible in
conventional single-layered forms. In parallel, we are developing new modeling and design
tools that would be critical for successful implementation of such multilayer circuits.
Participating Faculty: Nirod K. Das (ndas@photon.poly.edu)
[1] N. K. Das, Generalized Reciprocity Analysis of Surface-to-Surface Transitions between
Multiple Transmission Lines, IEEE Transactions on Microwave Theory and Techniques,
pp.1164-1177, July 1993.
[2] N. K. Das, Methods of Suppression and Avoidance of Leakage from Conductor-Backed
Transmission Lines, IEEE Transactions on Microwave Theory and Techniques, pp.169-181,
February 1996.
[3] G. K. C. Kwan and N. K. Das, Coaxial Probe to Parallel-Plate Dielectric Waveguide
Transition: Analysis and Experiment, IEEE Transactions on Microwave Theory and
Techniques, pp.1609-1620, June 2002.
11
Wave-Plasma Interactions in Artificial Modification of the
Ionosphere and Magnetosphere by Powerful Radio Waves
Background—A major facility for conducting experiments related to basic radio
science research as well as DoD missions is under development in Gakona, Alaska, as
part of the High Frequency Active Auroral Research Program (HAARP). The present
HAARP HF transmitting system is being expanded from a phased-array antenna of 48
elements to one with 180 elements. After completion of this upgrading, its maximum
effective radiated power (ERP) will exceed 1 GW. A backscatter radar (450 MHz) will
also be installed soon near the heating site to improve the remote sensing capability of
the HAARP. A key objective of the program is to explore physical processes that can
be initiated in the ionosphere and magnetosphere via interactions with high power radio
waves. Shown in Fig. 1 is a photo of the HAARP HF transmitting system before being
upgraded.
Two DoD missions of the HAARP program are 1. an ionospheric virtual antenna for
underwater communications and 2. an in-situ array of ELF/VLF transmitters for the
population control of radiation belt electrons.
Motivation— Signals in communications with submerged submarines have to
penetrate deeply into seawater, which is a conducting dielectric; the relative dielectric
constant r  72 and the conductivity   4 S/m. Thus the attenuation constant  for the
high frequency wave is rather high. Fortunately, the attenuation constant decreases with
the wave frequency. It has the dependence  = 410f Np/m for f  1 GHz. Hence,
the wave penetration problem can be resolved by adopting very low frequency carrier.
For example, choosing f = 100 Hz leads to  = 4102 Np/m and the penetration depth
 = 25 m. However, the wavelength of 100Hz wave is 3000 km. To implement a high
power and large size antenna (megawatts and hundreds of kilometers) on the ground is
costly and has to face environmental impact problems.
In the magnetosphere, very energetic electrons (in MeV level) in the radiation belts
have strong impact on space systems, which are designed to survive certain amount of
radiation (ionizing) dose accumulated during the lifetimes. Any unexpected radiation
flux enhancement can cause satellites to accumulate radiation damage much faster than
designed for, which leads to faster degradation of on-board active electronics.
Objective—to advance the understanding of wave-plasma interaction processes that help
for the realization of the future Naval/DoD systems for the missions.
12
Progress—In the polar region, an electrojet current appears frequently in the lower
ionosphere. A dc space charge field drives this current. Thus an amplitude-modulated
powerful HF wave modulated at ELF/VLF frequency can be introduced to modulate the
electron temperature, which results to the modulation of the electron conductivity in a
similar fashion. Consequently, the electrojet current driven by the background dc fields
becomes oscillating in time to act virtually as an antenna. The ac part of the current
becomes the source current of ELF/VLF radiation. A cartoon showing the antenna and
its radiation is presented in Fig. 2. Our research effort is to continuously improve the
antenna efficiency and the signal quality,1-3 which are critical to practical applications.
Our recent work4 showed that whistler waves could introduce chaotic scattering on
energetic electrons; thus it can be an effective approach for controlling the population of
energetic electrons in the radiation belts. This process is elaborated in Fig. 3. The
threshold conditions are determined by the transition of the surface of section plots from
regular to chaotic and by the decrease of the pitch angle to be less than the loss cone
angle. This is demonstrated by the sequence of surface of section plots (a-c) and pitch
angle scattering plots (d-f) presented in Fig. 4; the wave magnetic field B1 is normalized
to the background magnetic field B0, i.e., B1/B0; six trajectories corresponding to 0/
= 3.65-3.9 with 0.05 increment are drawn in the same plot to show the frequency effect
and to determine the optimal wave frequency. As shown, the trajectory of 0/ = 3.9
electron becomes the most chaotic at B1/B0 ~ 0.006 and its pitch angle is reduced to
about 300 at B1/B0 ~ 0.015.
Participating Faculty: Spencer Kuo (spkuo@rama.poly.edu)
Collaborators: Drs. James T. Huynh, Paul Kossey, Steven Kuo, and Prof. M. C. Lee
Sponsors: the High Frequency Active Auroral Research Program (HAARP) and the
Office of Naval Research (ONR)
1
S. P. Kuo, M. C. Lee, P. Kossey, K. Groves, and J. Heckscher, Geophys. Res. Lett., 27, 85, 2000.
2
S. P. Kuo, S. H. Lee, and P. Kossey, Phys. Plasmas, 9, 315, 2002.
3
S. P. Kuo and S. H. Lee, Radio Sci., 39, RS1S32 (1-5), 2004.
4
S. P. Kuo, P. Kossey, J. T. Huynh, and S. S. Kuo, IEEE Trans. Plasma Sci., 32(2), 362-369,
2004.
13
A Microwave-augmented Plasma Torch as an
Igniter/Fuel Injector in a Scramjet Engine
Motivation—The development of the scramjet propulsion system is an essential part of the
development of hypersonic aircraft and long-range scramjet-powered air-to-surface missiles
with Mach-8 cruise capability. Shown in Fig. 1 is a schematic of a conceptual Ajax vehicle.
As shown at the bottom of the vehicle, this engine has a simple structure as required by the
hypersonic aerodynamics. Basically, the combustor has the shape of a flat rectangular box
with both sides open. Air in taking through the frontal opening mixes with fuel for
combustion and the heated exhaust gas at the open end is ejected out through a MGD
accelerator and a nozzle to produce the engine thrust. The hydrocarbon-fueled scramjet in a
typical startup scenario, the fuel-air mixture will not auto-ignite. Moreover, the residence
time of fuel through the combustion region is short, of order 1 ms. Thus some ignition aids
are necessary to initiate and to hold main-duct combustion.
Objective—develop a plasma torch to be a viable Igniter/Fuel Injector in a Scramjet Engine;
it requires that the torch can be operated at low flow rate and yet can deliver large amount of
energy as well as penetrate deeply into the supersonic crossflow.
Progress—The torch module patented by Kuo et al.1 can run in dc or low frequency ac
mode and can produce high power (a few kW in 60-Hz periodic mode2 or hundreds of kW in
pulsed mode3) torch plasmas. Shown in Figs. 2a and b are two images of torch plumes,
corresponding to (a) in a quiescent environment and (b) in a supersonic crossflow. As shown
in the Fig. 2b, the supersonic crossflow causes significant deformation in the shape of
plasma torch. A comparison of Fig. 2a to Fig. 2b indicates that the penetration height of the
torch is reduced significantly as the plume is swept downstream by the high-speed flow.
The combustion efficiency in a supersonic combustor depends strongly on the plasma
enthalpy as well as its spatial distribution (i.e., the penetration height of the torch). This torch
module run in 60-Hz periodic mode has been evaluated as an igniter in a test engine. It was
found that this igniter produced a substantial flame plume as illustrated in Fig. 3, which
shows a single frame taken from video recordings of the plasma torch in operation 5 cm
downstream of the ethylene-fueled single-hole injector.
A new microwave-augmented plasma torch that has enhanced plasma enthalpy and size (by
the microwave) is being developed. It combines a new torch module with a rectangular
microwave cavity in the form of a microwave adaptor. The new torch module is similar to
the previous one, except it is longer and integrates the gas plenum chamber into it; moreover,
a tungsten tube, which provides a port for fuel injection, replaces the original central
electrode of a tungsten rod. The torch module is used not only to generate the arc plasma, but
also to couple the microwave power from the cavity to the arc plasma for plasma
enhancement. A photo of this torch device is presented in Fig. 4, in which a magnetron
whose transmitting antenna inserts into the cavity from the other side (non-tapered section) is
also shown.
The torch was tested to operate in the open air using compressed air as the feedstock. It could
run stably over a very large flow rate range, with flow speed from subsonic to supersonic.
The effect of microwave on the height and volume of the torch plasma varies with the gas
flow rate. This effect is particularly significant at low gas flow rate.
14
This is demonstrated by the plume images, presented in Figs. 5a to c, of the torch plasmas
generated before and after the magnetron is turned on, where the air supply pressure is 1.16
atm. A comparison of Fig. 5c to Fig. 5a clearly indicates that the microwave significantly
increases the size and the volume of the torch plasma. Moreover, microwave also
significantly enhances the luminosity of the plasma plume, which provides an indirect
indication on the enhancement of the plasma enthalpy.
Participating Faculty: Professor Spencer Kuo (spkuo@rama.poly.edu)
Collaborators: Drs. Daniel Bivolaru, Skip Williams, and Cam Carter
Sponsor: Air Force Office of Scientific Research (AFOSR).
1
S. P. Kuo, Daniel Bivolaru, Campbell D. Carter, Lance Jacobsen, and Skip Williams,
“Operational Characteristics of a Periodic Plasma Torch”, IEEE Trans. Plasma Sci., 32(1),
262-268, 2004.
2
S. P. Kuo, E. Koretzky, and L. Orlick, “Design and electrical characteristics of a modular
plasma torch,” IEEE Trans. Plasma Sci., 27(3), 752-758, 1999; “Methods and Apparatus
for Generating a Plasma Torch,” United States Patent No. US 6329628 B1, Dec. 11, 2001.
3
S. P. Kuo and Daniel Bivolaru, “A pulsed torch Plasma in a Mach 2.5 supersonic
crossflow,” submitted to IEEE Trans. Plasma Sci..
15
The Plasma Mitigation of the Shock Waves in
Supersonic/Hypersonic Flights
Motivation—Shock waves have been a detriment for the development of
supersonic/hypersonic aircrafts, which have to overcome high wave drag and surface heating
from additional friction. The design for high-speed aircraft tends to choose slender shapes to
reduce the drag and cooling requirements. While that profile is fine for fighter planes and
missiles, it has long dampened dreams to build a wide-bodied airplane capable of carrying
hundreds of people at speeds exceeding 760 mph. This is an engineering tradeoff between
volumetric and fuel consumption efficiencies and this tradeoff significantly increases the
operating cost of commercial supersonic aircraft. Moreover, shock wave produces notorious
sonic boom on the ground. It occurs when flight conditions are changing to cause shock
wave unstable. The faster the aircraft flies, the larger the boom. The noise issue raises
environmental concerns, which have precluded for example, the Concorde supersonic
jetliner from flying overland. A physical spike is used in the supersonic/hypersonic object to
improve its body aspect ratio for reducing the wave drag. However, the additional frictional
drag occurring on the spike structure and related cooling requirements limit the performance
of a physical spike. Therefore, the development of new technologies for the attenuation or
ideal elimination of shock wave formation around a supersonic/hypersonic vehicle is
essentially needed.
Objective—to advance the understanding of plasma effects on the shock wave structure.
Experimental Progress—A cone-shaped model1-3 having a 600-cone angle was used as a
shock wave generator in a Mach 2.5 wind tunnel. The tip and the body of the model were
designed as two electrodes with the tip of the model designated as the cathode for gaseous
discharge. 60 Hz/DC pulsed power supplies were used in the discharges for plasma
generation. The produced plasmas acted as different types of spikes, which deflected the
incoming flow before the flow reached the original (baseline) shock front location4. The
modification effect of a plasma spike on the shock wave formed in front of the model was
explored by examining shadowgraphs of the flow field taken during wind tunnel runs.
Presented in Fig.1a is a baseline shadowgraph of the flow field in the absence of the plasma
spike, which shows a usual attached conical shock over the model. The flow is from left to
right.
The modification effect depends on the density and volume of the plasma spike produced by
the discharge, which varies with time. This time varying spike is expected to cause the shock
front position to also vary in time. This is demonstrated in Fig. 1, which includes a sequence
of six shadowgraphs showing the responses of the shock wave to the growth and decay of
the plasma spike in a discharge cycle. The growth and decay of the plasma spike are
manifested by the variation of the background brightness in the shadowgraphs. First
shadowgraph shown in Fig. 1a is dark, representing the baseline one obtained in the case that
the discharge is off. As the plasma spike is intensified to reach the peak, its modification
effect on the shock structure as shown in Fig. 1d also reaches the maximum. The shock front
becomes very diffusive and spreads from the one shown in Fig. 1c to the further upstream
region. The pronounced influence of plasma on the shock structure is clearly demonstrated.
The diffused form of the shock front is an indication of shock wave being weakened by this
plasma spike. This is an encouraging result, evidencing the effectiveness of this plasma
16
scheme in reducing wave drag at supersonic speeds. It is noticed that as the shock front
moves upstream its shock angle also increases.
Numerical SimulationWe use a wedge5 of angle 150 to simulate the cone model
used in the experiment. A uniform airflow from left to right with a velocity V0 = V0x^
encounters a two-dimensional plasma spike before noticing the presence of a
symmetrical wedge on its way. Plasma is generated by the gaseous discharge in an
imposed electric field. The results of two cases with  = 0.8, and 0.65 are presented in
Fig. 2, in which the baseline shock front (i.e.,  = 1 case) is also presented for
comparison, where  is related to the plasma density. As shown the shock front moves
upstream as the plasma spike intensifies. It is found that shock becomes detached from
the wedge as the strength of the plasma spike exceeds a critical level. In this example
for a Mach 2.5 flow over a 150 wedge, the critical level is determined by  = 0.65,
which converts to the peak electron density n0 = 6.51013 cm. This electron density is
achievable by a diffusive arc discharge. The shock fronts presented in Fig. 2 correspond
to different plasma spike’s intensities, which resembles the temporal variation of the
discharge in one cycle. A good qualitative agreement between the theoretical results
presented in Fig. 2 and the experimental results presented in Fig. 1 is shown.
Continuing WorkNumerical simulation with three-dimensional cone model.
Participating Faculty: Spencer Kuo (spkuo@rama.poly.edu)
Collaborators: Drs. Daniel Bivolaru and Steven Kuo
Sponsor: Air Force Office of Scientific Research (AFOSR).
S. P. Kuo, I. M. Kalkhoran, D. Bivolaru, and L. Orlick, “Observation of shock wave elimination by a
plasma in a Mach-2.5 flow,” Phys. Plasmas, 7(5), 1345-1348, 2000.
2
S. P. Kuo and Daniel Bivolaru, “Plasma effect on shock waves in a supersonic flow,” Phys. Plasmas,
8(7), 3258-3264, 2001.
3
Daniel Bivolaru and S. P. Kuo, “Observation of supersonic wave mitigation by plasma aero-spike,”
Phys. Plasmas, 9(2), 721-723, 2002.
4
S. P. Kuo, “Conditions and a physical mechanism for plasma mitigation of shock wave in a supersonic
flow,” Physica Scripta, 70, 161-165, 2004.
5
S. P. Kuo and Steven S. Kuo, “A physical mechanism of non-thermal plasma effect on shock wave,”
Phys. Plasmas, accepted for publication.
1
17
A Portable Arc-seeded Microwave Plasma Torch and Its
Application for Decontamination of Biological Warfare Agents
UniquenessMicrowaves can provide electrodeless discharge to produce relatively
large volume plasma with no need of gas flow through the discharge to stabilize it. With
seeding, a low Q cavity having a relatively large exit hole to increase the diameter of
the torch can be used. It turns out that a larger cavity hole also helps the evanescent
microwave electric field to reach farther out of the hole. Therefore, the new type of
arc/microwave hybrid plasma torch developed in this research effort does not need gas
flow in its operation and yet can produce sizable plasma outside the cavity. A patened
torch module1 used to generate the seeding plasma adds the flexibility to introduce gas
flow in the operation. Gas flow can increase the size as well as the energy of the torch
plasma. This microwave plasma torch (MPT) device is designed to be portable2. Other
unique features of the design include 1) Rectangular cavity, rather than cylindrical, 2)
Torch plasma streams out of the cavity from the sidewall, rather at the end wall, and 3)
Torch plasma is energized by the TE mode electric field, rather than by the TM mode.
MotivationThis torch runs in a 60 Hz periodic mode and can be operated in a wide
range of airflow rate. Shown in Fig. 1 is a photo of the device and the plasma torch; the
airflow rate is 1.133 l/s.The emission spectroscopy of the torch was examined2. As
shown in Fig. 2, the spectral line of O I (777.194 nm) indicating relatively high atomic
oxygen content in the torch was observed. This finding motivates the current research
applying this plasma torch for the decontamination of biological warfare agents (BWA)
such as bacterial spores. This is because the generated atomic oxygen is a reactive
oxygen species (ROS). It reacts with nucleic acids, lipids, proteins and sugars of BWA.
The oxidation of lipids, reducing sugars and amino acids leads to the formation of
carbonyls and carbonyl adducts such as 4-hydroxy-2-nonenal (HNE). ROS are also
responsible for deamidation, racemization and isomerization of protein residues. These
chemical modifications result in protein cleavage, aggregation and loss of catalytic and
structural function by distorting secondary and tertiary protein structures. These
irreversibly oxidatively modified proteins cannot be repaired. This occurrence is known
as protein degradation. Through these chemical reactions, most BWA are converted by
ROS to carbon dioxide and water.
Objectiveto develop a decontamination tool that is capable of selectively and
effectively destroying BWA for biodefense.
ProgressIn the decontamination experiments3, B. cereus ATCC 11778 spores were
chosen as a stimulant substitute for B. anthracis (i.e., Anthrax). Three distances of 3, 4,
18
and 5 cm were chosen to place the samples for exposure. After plasma treatment, the
treated spores and debris were removed from the glass slides by means of extensive
sonication using tissue culture water. The mixtures were plated onto Petri dishes with
TSA media and incubated at 37oC for 16 hours. After the incubation, the resulting
colony forming units (CFU) were counted. The counted results then compare with the
control CFU (about 106 per sample before the treatment) provided by the supplier
company to determine the decontamination efficacy. The efficacy of the plasma torch
on decontamination of B. cereus is demonstrated in Fig. 3, which contains two images
of the remaining CFU in the 10-1 diluted samples after 3-sec and 6-sec plasma
treatments. The exposure distance was 3 cm.
The CFU counts N from the experimental results were normalized to the initial number N0.
These data points are presented in Fig. 4 and are fitted by straight lines as the kill curves for
dried B. cereus spores exposed to the plasma torch effluent at three exposure distances: 3, 4,
and 5 cm. The x-axis is exposure times in seconds and the y-axis displays the log of the ratio
of the number of viable spores remaining (N) to the CFU control number (N0). The time
required to reduce the viable (BC) spore population by a factor of 10 by the MPT in this
graph for 3, 4 and 5 cm distances are calculated to be 2.09, 2.84, 4.08 seconds. The results
are compared with previously reported decontamination of Bacillus globigii (BG) spores
using APPJ4 (dashed line) and hot gas (dotted lines), which require about 4.5 and 45
seconds.
Participating Faculty: Spencer Kuo (spkuo@rama.poly.edu)
Collaborators: Dr. Olga Tarasenko and Professor Kalle Levon
Sponsors: Air Force Office of Scientific Research (AFOSR) and the Othmer Institute
at Polytechnic University.
1S.
P. Kuo, E. Koretzky, and L. Orlick, “Design and electrical characteristics of a modular plasma
torch,” IEEE Trans. Plasma Sci., 27(3), 752-758, 1999; “Methods and Apparatus for Generating a
Plasma Torch,” United States Patent No. US 6329628 B1, Dec. 11, 2001.
2S. P. Kuo, Daniel Bivolaru, Henry Lai, Wilson Lai, S. Popovic, and P. Kessaratikoon “Characteristics
of An Arc-seeded Microwave Plasma Torch,” IEEE Trans. Plasma Sci., 32(4), 1734-1741, 2004.
3Wilson Lai, Henry Lai, Spencer P. Kuo, Olga Tarasenko, and Kalle Levon, “Decontamination of
biological warfare agents by a microwave plasma torch,” Accepted by Physics of Plasmas.
4H. W. Herrmann, I. Henins, J. Park, and G. S. Selwyn, “Decontamination of chemical and biological
warfare (CBW) agents using an atmospheric pressure plasma jet (APPJ),” Phys. Plasma, vol. 6 no.
5, pp. 2284-2289, 1999.
19
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II.Systems, Control and Signal
Processing
20
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. Control of Communication
Analysis and
.
Networks ..
In the past decade, the analysis and control of communication networks attracts great
research interests. As an example, optimization tools have been successfully applied to flow
control problems in Internet. The design objective of optimization-based flow control is to
maximize the overall network utility function, subject to the constraints of link capacities. In
[5], we solve this problem using a modified Aitken Extrapolation algorithm. Furthermore,
we perform convergence speed analysis for optimization-based flow control algorithms.
Except for the utility and cost optimization problem, recently, great attention is paid to
Internet congestion control since congestion causes packet loss and results in network underutilization (Figure 1). We notice that, compared with the large body of work on stability
analysis for existing congestion control schemes, the synthesis of nonlinear controllers with
improved performance has not received enough attention. We focus on designing new AQM
schemes to stabilize the nonlinear network model, with particular interest in output feedback
design, owing to the advantage of only measuring limited output information--buffer queue
length. Previously, the output feedback design for AQM schemes is based on linearized
model with known network parameters. With the help of Lyapunov design technique,
adaptive feedback linearization and filtering techniques, we design a new, nonlinear
controller to achieve both asymptotic stabilization and adaptation to unknown parameters
[2]. The output feedback solution represents a nontrivial application of modern nonlinear
control theory. We also believe that the design in [2] should provide benefits to future
networking technical developments and serve as guidance for distributed protocol designs.
There have been continued interests in applying modern control theory to systematically
address new challenges in large-scale networks. Currently, many existing work on
controlling communication networks are based upon linear control techniques. Hard
nonlinearities, such as saturation caused by capacity constraints, have not been thoroughly
addressed, especially when designing control schemes for large-scale networks. In this
project, we apply nonlinear control theory to cope with saturation constraints and nonlinear
disturbances. In [1], [3] and [4], the constrained regulation of a class of network systems is
studied. Explicit conditions are identified under which the problem of asymptotic regulation
against unknown traffic interferences is solvable, with control and state saturations. We
achieve either asymptotic or practical regulation for a single-node system in [1]. We also
propose decentralized, discontinuous control laws to achieve asymptotic regulation of
cascaded nodes and large-scale networks in [3], [4]. Our research demonstrates that tools
from nonlinear system theory can play an important role in tackling “hard nonlinearities”
and “unknown disturbances” for controlling communication networks. The control
architecture for a single-node system is shown in Figure 2.
Another line of our research is the analysis and design of wireless ad hoc broadcasting
protocols. Ad hoc network is composed of a set of self-organized users that agree to relay
packets for each other. Different from conventional cellular wireless systems, ad hoc
networks have no fixed infrastructure and central administration. Furthermore, each user can
21
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move randomly and the. topology changes occur frequently. In such distributed and dynamic
networks, broadcasting. is widely used to distribute small control packets such as route
request packets and warning
packets. Numerous broadcasting protocols are proposed in
.
literature to minimize overhead
and maximize reception ratio. Different from conventional
.
simulation based analysis methods, we theoretically analyze these protocols. Our results in
[6], [7], [9] reveal the relation between broadcasting efficiency and network parameters.
Furthermore, we have proposed a mobility sensitive mechanism to improve protocol
performance in highly-mobile environment [8]. Broadcasting protocols based on the
proposed mechanism are adaptive to nodal movement and hence reduce packet loss rate due
to mobility.
end host
Internet
xref
Bottleneck
link router
Lost packects
C
x
-
end host
Figure 1 Packets loss caused by Internet congestion
controller
Figure 2 Control configuration for a network node
Key-words: Congestion control, TCP/IP, Broadcasting, Large-scale systems.
Participating Faculty: Z. P. Jiang (zjiang@control.poly.edu) and S. Panwar
(panwar@catt.poly.edu)
Websites: http://ctrl.poly.edu/, http://catt.poly.edu/CATT/
Research supported in part by the CATT and NSF.
[1] Y. Fan, Z.P.Jiang and H. Zhang, Network flow control under capacity constraints: a case study,
Systems & Control Letters, Vol. 55, No. 8, pp. 681-688, 2006.
[2] Y. Fan and Z. P. Jiang and S. Panwar, An adaptive control scheme for stabilizing TCP, Proc. 5th
World Congress on Intelligent Control and Automation, Hangzhou, China, 2004.
[3] Y. Fan and Z.P.Jiang, A nonlinear flow control scheme under capacity constraints, Acta
Automatica Sinica, vol. 31, no. 1, pp. 64-74, Jan. 2005.
[4] Y. Fan, Z.P. Jiang and X. Wu, A control-theoretic approach to stabilizing queues in large-scale
networks, IEEE Communications Letters, Vol. 9, No. 10, pp. 951-953, 2005.
[5] H. Zhang, Z.P. Jiang, Y. Fan and S. Panwar, Optimization-based flow control with improved
performance, Communications in Information and Systems, vol. 4, No. 3, pp. 235-252, 2004.
[6] H. Zhang and Z.P.Jiang, Analysis of two ad hoc broadcasting protocols, IEEE wireless
Communications and Networking Conference (WCNC), Atlanta, GA, March, 2004.
[7] H. Zhang and Z.P. Jiang, Performance analysis of broadcasting schemes in mobile ad hoc
networks, IEEE Communications Letters, vol. 8, no. 12, pp. 718-720, Dec. 2004.
[8] H. Zhang and Z.P.Jiang, Mobility sensitive broadcast algorithms in highly mobile ad hoc
networks, to appear in Ad Hoc & Sensor Wireless Networks.
[9] H. Zhang and Z.P. Jiang, Modeling and performance analysis of ad hoc broadcasting schemes,
Performance Evaluation, Vol. 63, pp. 1196—1215, 2006.
22
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Stability of.. Nonlinear Dynamical Systems
.
.
Stability theory has played an important role in many scientific and engineering disciplines.
In the domain of automatic control, advances in modern control system design are closely
tied to Lyapunov theory. According to Lyapunov theory [1], the stability of a general
dynamical system can be tested based upon existence of an appropriate function, widely
known as Lyapunov function. Recently, Sontag has generalized Lyapunov theory to
continuous-time dynamical systems with disturbance inputs, and coined this under the name
of input-to-state stability (ISS) theory. Basically, ISS captures both internal (transient
performance) and external (bounded-input bounded-state) stability properties. ISS theory has
gained wide popularity and has been applied to numerous control issues of fundamental
importance such as observer design, robust control, adaptive tracking, nonlinear feedback
stabilization and decentralized nonlinear control. Because of the discrete nature of computeraided control system design, we have extended ISS theory to discrete-time dynamical
systems with disturbance inputs. A converse Lyapunov theorem for robust discrete-time
stability and small-gain theorems for nonlinear and interconnected discrete-time systems
have been proposed. Sufficient and necessary conditions for input-to-state stabilization of
discrete-time control systems are obtained, along with several equivalent characterizations of
discrete input-to-state stability. Some applications to nonlinear discrete control have also
been discussed. Another line of our recent research on stability theory is the extension of the
celebrated LaSalle’s Invariance Principle for complex dynamical systems; see [5] for such
an extension to general nonlinear and time-varying systems. Further control applications of
these novel stability criteria are ongoing research topics.
Key-words: nonlinear systems, input-to-state stability, discrete-time.
Participating Faculty: Z. P. Jiang (e-mail: zjiang@control.poly.edu, Web:
http://ctrl.poly.edu)
Collaborators: Profs. Yuan Wang, Yuandan Lin and T.C. Lee
Research supported by NSF
[1] A. N. Lyapunov, Problème gėnėral de la stabilitė du movement. Ann. Fac. Sci. Toulouse, vol. 9,
pp. 203—474, 1907.
[2] Z. P. Jiang and Y. Wang, Input-to-state stability for discrete-time nonlinear systems, Automatica,
vol. 37, no. 6, pp. 857-869, June 2001.
[3] Z. P. Jiang and Y. Wang, A converse Lyapunov theorem for discrete-time systems with
disturbances, Systems & Control Letters, vol. 45, pp. 49--58, 2002.
[4] Z. P. Jiang, Y. Lin and Y. Wang, Nonlinear small-gain theorems for discrete-time feedback
systems and applications, Automatica, vol. 40, pp. 2129--2136, 2004.
[5] T. C. Lee and Z. P. Jiang, A generalization of Krasovskii-LaSalle theorem for nonlinear timevarying systems: Converse results and applications, IEEE Trans. Automat. Control, Vol. 50, No. 8 ,
pp. 1147-1163, 2005..
23
Applied
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.
Nonlinear
.
.
.
Control
The development of control theory for nonlinear systems has been driven by practical
applications arising from various engineering fields. A recent trend in nonlinear control is to
introduce novel nonlinear feedback design tools for controlling important classes of plants
with strong nonlinearities [1]. Our earlier studies are concerned with the development of
tools for general nonlinear control systems described by ordinary differential or difference
equations [2, 3, 4].
Our recent research effort has been directed at addressing the problems of stabilization and
trajectory tracking for an important class of nonlinear underactuated mechanical systems
such as mobile robots and surface ships. The fundamental challenge from controlling such
nonlinear systems is that there are more degrees of freedom than the number of available
control inputs. As a consequence, linear control and conventional nonlinear control fail to be
applicable to solving the stabilization problem or only yield solutions to local tracking
control with nonglobal domain of attraction. This project proposes a new approach to the
problem of global stabilization and trajectory tracking by means of Lyapunov techniques and
adaptive system theory. Some preliminary results have been presented in [5, 6]. Other related
references can be found at our website.
Key-words: Nonlinear control, Lyapunov methods, Underactuated mechanical systems,
Ship control.
Participating Faculty: Z. P. Jiang (zjiang@control.poly.edu)
Website: http://eeweb.poly.edu/faculty/jiang/ or, http://ctrl.poly.edu
Research supported by NSF
[1] P. Kokotovic and M. Arcak, Constructive nonlinear control: a historical perspective.
Automatica, vol. 37, pp. 637-662, 2001.
[2] Z. P. Jiang, I. Mareels, D.J. Hill and J. Huang, A unifying framework for global
regulation via nonlinear output feedback: from ISS to iISS, IEEE Trans. on Automatic
Control, vol. 49, no. 4, pp. 549-562, 2004.
[3] Z.P. Jiang, Decentralized control for large-scale nonlinear systems: a review of
recent results, Special Issue in honor of Prof. Siljak's 70th birthday, J. Dynamics of
Continuous, Discrete and Impulsive Systems, pp. 557-572, Vol. 12, 2004.
[4] Z. P. Jiang, I. Mareels, A small gain control method for nonlinear cascaded systems
with dynamic uncertainties, IEEE Trans. Automat. Contr., vol. 42, pp. 292-308, 1997.
[5] K. D. Do, Z. P. Jiang and J. Pan, Universal controllers for stabilization and tracking
of underactuated ships, Systems & Control Letters, vol. 47, pp. 299--317, 2002.
[6] K.D. Do, Z.P. Jiang and J. Pan, Robust adaptive path following of underactuated
ships Automatica, Vol. 40, No. 6, pp. 929-944, 2004.
24
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Robust Adaptive
Nonlinear Control
.
.
System Designs
.
We have developed a powerful and flexible paradigm for dynamic high-gain based design of
controllers and observers for various classes of nonlinear systems. The design technique is
applicable in both the state-feedback and the output-feedback cases. The technique utilizes a
state scaling generated through an appropriately designed dynamics driven by the measured
outputs of the system. The resulting controller and observer are algebraically simple
requiring no recursive computations and the associated Lyapunov functions have a simple
scaled quadratic form. The stability analysis is based on the solution of a pair of coupled
matrix Lyapunov equations. Necessary and sufficient conditions for the solvability of the
coupled Lyapunov equations have been obtained in our recent results.
The approach provides a unified design procedure applicable to both lower triangular
(feedback) and upper triangular (feedforward) systems and also to some classes of
polynomially bounded systems without requiring any triangularity in the system structure.
The controller provides strong robustness properties and allows coupling with a dynamic
high-gain observer whose design is dual to that of the controller to obtain output-feedback
stabilization and tracking results. This represents the first output-feedback result for
feedforward systems. The controller and observer designs in the case of feedforward
systems are strongly parallel to the designs in the case of strict-feedback systems suggesting
that the proposed technique could allow further extensions for feedforward systems along
various lines that have been hitherto investigated only for strict-feedback systems. In both,
the strict feedback and the feedforward cases, a greater generality and complexity of bounds
on uncertain functions in the system does not increase the complexity of the control law, the
observer, and the Lyapunov function, but is instead handled through the dynamics of the
scaling parameter. Furthermore, the scaling parameter dynamics can be designed to provide
robustness to various perturbations including unknown parameters, additive disturbances,
inverse dynamics, and appended Input-to-State Stable (ISS) dynamics. A generalized scaling
technique utilizing arbitrary powers of the scaling parameter has been developed to weaken
the assumptions on the system and to extend the results to non-triangular systems. Current
research effort on this topic is focussed on extending the results in the following directions:
1) systems with ISS appended dynamics considering general interconnections (dependent on
all states) 2) adaptive control without a priori bounds on unknown parameters 3)
decentralized control for large-scale systems with each subsystem control input designed
using the dynamic high-gain scaling based technique 4) disturbance attenuation 5) relaxation
of assumptions by considering more general scaling patterns/ multiple scalings and more
general scaling dynamics.
25
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Feedback interconnection of nonlinear systems
Key-words: Nonlinear control, adaptive control, robust control, high-gain designs,
feedback and feedforward systems.
Participating Faculty: Farshad Khorrami (khorrami@smart.poly.edu)
Website: http://crrl.poly.edu/pub1.html
Funding Sources: NSF and ARO
26
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Development. of Hardware/Software Architecture
.
for Autonomous
Unmanned Vehicles
.
.
There are many civilian (e.g., weather forecasting, traffic monitoring, police operation, fire
fighting, port security) and military applications (e.g., surveillance, target identification,
ordinance delivery, communication relay) for the use of unmanned autonomous vehicles
(UAV). For aerial vehicles, current FAA requirements analyses identify two possible means
by which UAVs may be accepted into civilian airspace: 1) requiring all UAVs to have the
necessary transponder hardware to identify themselves to the control tower or 2) requiring
UAVs to have autonomous obstacle avoidance systems (OAS). This latter approach of
requiring OAS on UAVs is favored by the industry. An autonomous unmanned aircraft
equipped with an OAS will be able to carry out a multitude of missions requiring flight to a
designated target without benefit of remote piloting or any prior knowledge of the local
geography. Our on-going effort is in the direction of development of a low resource OAS
and its implementation on a small autonomous helicopter.
There has been much interest in UAVs in the past few decades; however, miniaturization of
sensors, electronics, and fast microprocessors in the past decade have improved feasibility of
small autonomous vehicles with on board OAS. Nevertheless, this is a challenging problem
due to limitation of space/volume, payload capacity, power, and computational resources on
board a small UAV. We have been considering several classes of UAVs, namely unmanned
aerial vehicles, unmanned underwater vehicles, unmanned surface vehicles, unmanned
rotary wing aircrafts. The picture of our unmanned rotary wing aircraft and a hardware-inthe-loop simulation for this test bed are given below. We have on-going efforts in regard to
fixed wing aircrafts, unmanned surface vehicles (USVs), and unmanned underwater
vechicles ( UUVs).
Our small autonomous helicopter and its hardware-in-the-loop implementation
27
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Key-words: Autonomous
.
planning, control design.
.
.
.
vehicles, unmanned vehicles, obstacle avoidance, path
Faculty: Farshad Khorrami (khorrami@smart.poly.edu)
Website: http://crrl.poly.edu/pub1.html
Funding Sources: ARO and Industrial Funding
28
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Nonlinear ..Control for Electric Motors
.
.
Electromechanical actuators have been utilized in many applications from home appliances
to sophisticated guidance and control systems. Various electromechanical actuators such as
electric motors, hydraulic and pnuematic actuators, smart materials (e.g., piezoceramics,
magneto-restrictive materials, shape-memory alloys, electrorehological fluids, etc.) have
been considered. Modeling and control design for such actuators have been and are pursued
to achieve a higher level of performance. As a part of our on-going efforts, we consider
modeling and control design of electric motors, namely step motors, brushless DC motors,
and induction motors. These electrical motors are used in many applications; some requiring
a high level of accuracy and performance such as machines used in electronics industry for
assembly or semiconductor wafer probing and inspection.
To achieve high precision and bandwidth for the motors, we explore modeling of these
devices to the extent needed to provide a high performance controller but at the same time
amenable to model-based nonlinear designs. To this extent, we consider nonlinear and
adaptive controllers to derive robust and high performance feedback controllers which is
essential for applications that require high performance and accuracies. The recent nonlinear
and adaptive design tools have shown to be effective in designing robust controllers
achieving robust performance. We have utilized existing nonlinear tools and their extensions
to design robust adaptive controllers for various motors under full state or partial state
measurement (sensors less control). We have experimental test beds for such motors at the
Contol/Robotics Research Laboratory at Polytechnic University and one such test bed is a
dual axis linear stepper motor used in electronics industry. A picture of this set up is shown
below.
Our dual-axis linear stepper motor experimental test bed
29
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.
. modeling, nonlinear control, adaptive control, high speed
Key-words: Electric motors,
.
accurate step motors. .
.
.
Participating Faculty: Farshad Khorrami (khorrami@smart.poly.edu)
Publications: http://crrl.poly.edu/pub1.html
Funding Sources: NSF, ARO, and Industrial Funding
Book: F. Khorrami, P. Krishnamurthy, H. Melkote, Modeling and Adaptive Nonlinear
Control of Electric Motors, Spring Verlag, Heidelberg, 2003.
30
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Development.of an Ultra-Accurate High-Speed Six
. and Other Robotic Systems
DOF Manipulator
.
.
Dual-axis linear motors (i.e., Sawyer motors) are utilized in various manufacturing
applications such as electronics industry for assembly, packaging, lead bonding, and wafer
probing. In these applications, additional degrees of freedom are attained by using other
types of motors and mechanisms (e.g., geared motors or lead screws). Inherently, these
additional mechanisms degrade the overall performance of the system and various motor
technologies need to be employed to design a four to six degree of freedom (DOF)
manipulation system (four being common for many packaging and assembly operations).
We have considered the use of Sawyer motors to design a direct drive six DOF
manipulator. Many 6 DOF industrial manipulators have been built by various groups
and companies. The unique features of the proposed 6 DOF manipulator are that it is
direct drive, uses a single motor technology, has a large work space, is high speed, and
is capable of achieving high positional resolution. We have performed detailed
kinematic and dynamic modeling for this type of manipulators. Furthermore, we carried
out a kinematic optimization to maximize the manipulator workspace. The advocated
six degree-of-freedom positioning system is a tripod structure with inextensible limbs
actuated at the base by two dimensional linear stepper motors (although other types of
actuators may be utilized). The proposed manipulator achieves large range of motion in
all the six degrees of freedom. Furthermore, high resolution and high speed motion may
be achieved in all axes. A picture of our tripod manipulator is given below.
The tripod manipulators: 6 DOF design based on dual-axis linear motors.
31
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.
Key-words: Robotic .manipulators,
direct drive manipulators.
.
.
.
manufacturing systems, ultra-accurate robots,
Participating Faculty: Farshad Khorrami (khorrami@smart.poly.edu)
Website: http://crrl.poly.edu/pub1.html
Funding Sources: NSF and Industrial Funding
32
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.
. Control of Nonlinear Large-Scale
Decentralized
.
. Systems
Interconnected
.
Several real-world large-scale systems can be viewed as interconnections of linear/nonlinear
subsystems with constraints on information flow between the subsystems. We have
addressed the decentralized control problem for large-scale systems under various sets of
assumptions on the subsystem structures and interconnection topologies. We have also
applied these results to a variety of large-scale systems including power networks, smart
structures, and satellite formations. Our results on nonlinear control techniques have enabled
us to weaken the required assumptions on the structures of the individual subsystems and
also on the interconnection (or coupling) among the subsystems. We have also extended the
results to include adaptations to compensate for unknown system parameters and also to
provide robustness to uncertain terms and appended nonlinear dynamics. Furthermore, we
have investigated techniques to achieve decentralized attenuation of disturbance inputs and
provided explicit guaranteed bounds on the disturbance attenuation along with tuning
strategies to achieve desired disturbance attenuation properties through the proper choice of
controller parameters. Decentralization of the control may be achieved both through a
centralized or a decentralized design of the decentralized controllers. In our research, both
strategies have been utilized.
System
Subsystem i
Decentralized control of large-scale interconnected systems
1.
D
s
s
d
d
s
a
f
d
s
a
d
s
a
Key-words: Decentralized control, large-scale systems, nonlinear control, adaptation,
interconnected subsystems.
Participating Faculty: Farshad Khorrami (khorrami@smart.poly.edu)
Website: http://crrl.poly.edu/pub1.html
Funding Sources: NSF and ARO
33
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.
Joint Transmitter-Receiver
Design for
.
. and Noise Suppression
Interference
.
A fundamental design problem encountered in radar, sonar, and communication systems in
general, is that of jointly optimizing the transmitter and receiver, given, perhaps, some
knowledge of the channel. In the active sensor detection problem (e.g., radar, sonar), one is
concerned with judiciously selecting the operating band, transmit waveform modulations,
and receiver processing strategy, in order to maximize the probability of detecting the
presence of a “target”, while maintaining a prescribed rate of false alarm.
In the classical detection problem, the received signal is passed through an optimum receiver
to obtain a single output and at a specified instant, this output is used to decide the presence
or absence of a target. The problem in that case is to design the optimal transmit-receiver
pair so as to maximize the output signal-to-interference plus noise ratio (SINR) at the
decision instant. The solution turns out to be the dominant eigenvector associated with an
integral equation with appositive definite kernel [1] - [3].
Multichannel Optimization of Transmit-Receiver Waveforms
In a multi-channel domain, optimizing the transmitter and receiver set so as to maximize the
output signal-to-interference plus noise ratio (SINR) for target detection makes sense when
clutter or multipath is a leading source of interference. To excite various hidden modes of
the target and clutter for better target detection and clutter suppression in presence of noise, it
may be desirable to illuminate the target, for example, with both horizontally and vertically
polarized signals. The horizontally polarized signal will excite certain aspects of both target
and clutter, while failing to highlight other key features. By illuminating the scene
simultaneously with a vertically polarized signal those missing features can be high
lightened as well.
As in monostatic radar, if two noncolocated sensors that are polarized horizontally and
vertically are used to transmit and receive the returns, we have a two input, two output
multichannel situation with a 2 x 2 transfer matrix representing the target. As usual the (1,1)
entry of this target transfer matrix represents the target transfer function associated with
horizontally polarized transmit and receive scenario etc. In presence of targets that respond
to transmitter diversity such as polarization, to maximize the output SINR, it becomes
necessary to jointly optimize the transmit signal vector and the receiver bank of filters in
presence of signal dependent interference and noise. This multichannel matched transmitterreceiver structure is superior to its scalar counterpart, since several aspects of the signal
dependent interference spectrum are ``brought to light'' in this case. The cross-interference
spectral matrices in fact contain much more information compared to the single channel
case, and despite the highly nonlinear nature of the problem, it is possible to derive a closed
form solution for the optimum matched receiver filter bank.[2]-[3].
34
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n(t )
Target
R
x
Tx
Clutter
Optimum Transmit-Receiver Design in Presence of Signal Dependent Interference
and Channel Noise
Waveform Diversity and Time-Reversal Processing
An interesting problem in this context is to integrate the waveform diversity option with the
“time-versed transmit” signal scheme that has been of interest in SONAR. In time-reversed
transmit scheme, a waveform is transmitted, and the return echo is time-reversed and
transmitted back to the target for a matched filtering action to take place at the target itself.
This process is continued iteratively till the target echo gets sufficiently amplified due to the
repeated coherent matched filtering at the target. An appropriate modification in the radar
context will be to use the transmitter waveform diversity approach to obtain a suitable initial
transmit signal.
Participating Faculty: S. Unnikrishna Pillai (pillai@hora.poly.edu)
Website: http://eeweb.poly.edu/~pillai
[1] S. U. Pillai, H. S. Oh, D. C. Youla and J. R. Guerci, Optimum Transmit-Receiver
Design in the Presence of Signal-Dependent Interference and Channel Noise, IEEE
Transactions on Information Theory, Vol. 46, No. 2, pp. 577-584, March 2000.
[2] S. U. Pillai, Multichannel Waveform Diversity for Improved Target Identification,
Second Tri-Service Waveform Diversity Workshop, Verona, NY, February 2004.
[3] S. U. Pillai and J. R. Guerci, Optimized Multichannel Waveforms with Application to
Polarimetrics, Proc. of the Adaptive Sensor Array Processing Workshop, MIT Lincoln
Laboratory, Lexington, MA, March 2002.
35
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.
.
.
.
. using a 3-D Motion-Selective
Video Coding
.
.
Wavelet Transform
.
The transmission, storage, and related processing of video are important technical
problems in today’s society. Progress related to the efficient representation of video is
of increasing importance for personal mobile electronics and for Internet applications.
Video coding algorithms are often based on motion-compensated predictive coding.
This project involves an original approach for video representation that is based on
recent developments in wavelet theory: recently developed transforms are designed to
overcome basic problems that degrade the performance of the wavelet transform when
it is applied to multidimensional data using the standard separable implementation. In
general, the representation and extraction of content from high dimensional data is a
problem for which there is a need for fundamental research.
This research involves a new approach to video coding based on the motion-selective 3D wavelet transform. The standard separable 3-D wavelet transform is rarely used for
video compression because it mixes 3-D orientations in its subbands; this artifact
reduces the effectiveness of the separable transform for providing an efficient
representation of video. However, the new 3-D wavelet transform is free of the mixing
artifact and gives a meaningful multi-scale decomposition for video. With the new
transform, it is more likely that the multiresolution framework, which has proved very
effective for image compression and efficient feature extraction, can also be effectively
applied to video representation.
The new transform isolates motion in different directions in separate subbands, so the
direction of motion can be inferred to some degree from the wavelet coefficients.
Participating Faculty: Ivan Selesnick (selesi@taco.poly.edu) and Yao
Wang (yao@vision.poly.edu)
Website: http://taco.poly.edu/selesi/
Collaborator: Anthony Vetro, Mitsubishi Electric Research Laboratories,
Cambridge, MA
Funded by NSF
[1] B. Wang, Y. Wang, I. Selesnick and A. Vetro. Video coding using a 3-D motionselective wavelet transform. Picture Coding Symposium (PCS), San Francisco,
December 2004.
[2] B. Wang, Y. Wang, I. Selesnick and A. Vetro. An investigation of 3D dual-tree
wavelet transforms for video coding. IEEE Int. Conf. on Image Proc. (ICIP), Singapore,
October 2004.
36
.
.
.
.
.
. Specialized Wavelet Transforms
The Design of
.
.
.
The simplest wavelet transform for multi-dimensional digital data is the criticallysampled separable wavelet transform. This transform uses a 1-D wavelet transform in
each dimension and is the one that is conventionally used. However, one way to
improve the performance of wavelet-based signal and image processing algorithms is to
use specialized wavelet transforms in place of the conventional wavelet transform.
There are several advances in the design of specific wavelet transforms that lead to
substantially improved performance. For example, the undecimated wavelet transform,
the steerable pyramid, and curvelet transform all give improved results in applications
involving multidimensional data. At Polytechnic we have been designing specialized
wavelet transforms, building upon the recently developed dual-tree transform, an
oriented complex-valued wavelet transform shown to be highly beneficial for multidimensional signal processing. This transform has several advantages over the
conventional multi-dimensional wavelet transform: (1) near shift invariance, (2)
directional selectivity, and (3) improved energy compaction. We have also been
developing expansive wavelet transforms (one that transforms an N-point signal into M
expansion coefficients with M > N) that possess properties not possible with a
critically-sampled transform.
Participating Faculty: Ivan Selesnick (selesi@taco.poly.edu)
Website: http://taco.poly.edu/selesi/
[1] I. W. Selesnick and A. F Abdelnour. Symmetric wavelet tight frames with two
generators. Applied and Computational Harmonic Analysis, 17(2):211-225, 2004.
[2] I. W. Selesnick. The double-density dual-tree discrete wavelet transform. IEEE
Trans. on Signal Processing, 52(5):1304-1314, May 2004.
[3] I. W. Selesnick. The design of approximate Hilbert transform pairs of wavelet bases.
IEEE Trans. on Signal Processing, 50(5):1144-1152, May 2002.
37
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.
.
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.
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.
.
38
.
.
.
.
.
. Probability Models for WaveletNon-Gaussian
.
Based Denoising
.
.
Non-Gaussian probability models are important for achieving high quality results in
wavelet-based image and video processing. Such probability models are the starting
point for the derivation of effective non-linear processing rules. The simplest method
for wavelet-based denoising is a thresholding rule. More advanced approaches begin
with a probability model for the wavelet coefficients and then obtain an estimator via
Bayesian estimation techniques, such as the MAP or MMSE estimator. For denoising,
several issues then arise: (1) What kind of probability distributions accurately represent
the wavelet coefficients? (2) How do we estimate the parameters of that distribution
from noisy data? (3) How do we estimate the noise-free wavelet coefficient from the
noisy wavelet coefficient using this probability model?
We are developing non-Gaussian probability models and algorithms for wavelet-based
denoising. While the multivariate Gaussian model is relatively easy to work with, it is
usually not accurate for wavelet-domain modeling natural signals. This is because
wavelet coefficients of natural imagery are generally (1) heavy-tailed, (2) approximately
uncorrelated, and (3) strongly dependent on adjacent coefficients (in scale and
spatially). These are characteristics the multivariate Gaussian can not achieve. We have
developed fast and effective non-linear denoising algorithms based on multivariate
Laplacian distributions and we are now working with mixtures of such distributions.
Based on this research, we have developed software for denoising digital X-ray images
that is used in a dental X-ray sensor manufactured by AFP Inc, a company that sells Xray machines and related imaging equipment to dentists. This software implements a
fast real-time algorithm for the reduction of signal-dependent noise in digital dental Xray images using a wavelet-based nonlinear signal processing algorithm.
Noisy Image
Processed Image
Participating Faculty: Ivan Selesnick (selesi@taco.poly.edu)
Website: http://taco.poly.edu/selesi/
[1] F. Shi and I. W. Selesnick. Class of heavy-tailed multivariate non-Gaussian
probability models for wavelet coefficients. Wavelet Applications in Signal and Image
Processing X (SPIE), San Diego, August 4-8, 2003.
[2] L. Sendur and I. W. Selesnick. Bivariate shrinkage with local variance estimation.
IEEE Signal Processing Letters, 9(12):438-441, December 2002.
[3] L. Sendur and I. W. Selesnick. Bivariate shrinkage functions for wavelet-based
denoising exploiting interscale dependency. IEEE Trans. on Signal Processing, 50(11):
2744-2756, November, 2002.
39
.
.
.
.
.
.
A Motion-Selective
3-D Wavelet Transform for
.
. of Imagery in Video Data
Enhancement
.
The standard separable 3-D wavelet transform is rarely used for the enhancement and
denoising of imagery in video data because it mixes 3-D orientations in its subbands.
However, the 3-D dual-tree complex wavelet transform is free of this problem and gives
a meaningful motion-based multi-scale decomposition for video data. Although the new
transform is non-separable, it is based on a mostly separable implementation so it is
reasonably efficient for implementation purposes. Because this transform provides a
multiresolution signal decomposition with out the orientation-mixing (motion-mixing)
that plagues separable 3-D wavelet transforms it is likely to yield superior results for
enhancement of imagery in video data. With this transform, it becomes feasible to
extend to video the recently developed high-performance wavelet-based enhancement
and denoising algorithms for image processing. Because the research on wavelet-based
image processing is extensive, this will potentially provide a wealth of new algorithms
for video processing.
Participating Faculty: Ivan Selesnick (selesi@taco.poly.edu)
Website: http://taco.poly.edu/selesi/
Funded by ONR
[1] F. Shi and I. W. Selesnick. Video denoising using oriented complex wavelet
transforms. Proc. IEEE Int. Conf. Acoust., Speech, Signal Processing (ICASSP),
Montreal, May 2004.
[2] I. W. Selesnick and K. Y. Li. Video denoising using 2D and 3D dual-tree complex
wavelet transforms. Wavelet Applications in Signal and Image Processing X (SPIE),
San Diego, August 4-8, 2003.
40
.
.
.
.
.
.
Wavelet Processing
for Positron Emission
.
.
Tomography
.
Positron Emission Tomography (PET) is used widely in medical research and clinical
applications. The instrumentation and reconstruction algorithms are highly developed,
however, the propagation of noise limits the accuracy of the images obtained using
PET. The accuracy can be improved by increasing the injected activity or the scan time,
but this is usually not a safe or practical solution. In this project, we are investigating
the use of wavelet-based denoising of the projection data for increasing the signal-tonoise ratio of the reconstructed image, while have as a goal the negligible loss of
resolution. Our preliminary work suggests that wavelet denoising may be able to
increase the signal-to-noise ratio by more than a factor of two.
Participating Faculty: Ivan Selesnick (selesi@taco.poly.edu)
Website: http://taco.poly.edu/selesi/
Collaborator: Nathaniel Albert, Massachusetts General Hospital, Boston.
[1] N. M. Alpert, A. Reilhac, T. C. Chio, and I. W. Selesnick. Wavelet Processing of
Dynamic PET Data: Lead into gold? Presented at the Annual Meeting of the Society of
Nuclear Medicine, June 2004.
41
.
.
.
.
.
. P2P Video Streaming System
On-Demand
.
.
.
In this project, we consider the design of a video streaming network (VSN) that enables
users to search and view on-demand enormous libraries of video content stored in the
Internet. Today’s VSNs deploy a dedicated set of servers to store and distribute content to
clients. Such infrastructure-based VSNs are extremely costly, both in terms of server cost
and Internet-connection cost. We propose to develop peer-driven VSNs, in which users’s
computers (called peers, typically, PCs, Macs and workstations) who ordinarily act as
streaming clients also act as streaming servers. Peers store and stream the video to the
requesting clients. With such an architecture, the cost of servers and the Internet access
would be borne by the users.
In a peer-to-peer (P2P) network, nodes may disconnect from the system at anytime without
warning. One of the major challenges with a P2P VSN is the distribution of high quality
video without glitches when the serving peers can disconnect from the Internet without
notice. Another important challenge relates to the relatively low uplink capacity of many of
the peers.
Our approach to P2P VSN is to encode each video into multiple sub-streams and to place
each sub-stream on a different server. When a client wants to see a video, multiple peers act
as servers, each sending a different sub-stream of the video to the client. After a short initial
delay, the client combines, decodes, and displays the video as the multiple sub-streams are
being delivered. When a serving peer disconnects in the middle of a streaming session, the
system will look for a replacement peer which is storing the same video sub-stream and
which has sufficient uplink bandwidth. The server selection and replacement can be done in
either a centralized manner (for example, by a central server governing all peers in the
system) or decentralized manner (for example, by the requesting client).
The figure below illustrates the proposed system architecture. In this illustrative example,
nodes 4 and 5 are each receiving a video. Initially, node 4 receives sub-streams from nodes 2
and 3, and node 5 receives from nodes 4 and 1. Then node 2 goes down, and the system
recovers by assigning node 6 as a replacement. The video coding, sub-stream placement,
server selection and replacement, and sub-stream delivery are designed so that visual quality
at node 4 is only slightly degraded while the system is locating a replacement after node 2
goes down.
By coding a video into multiple sub-streams and distributing the sub-streams from separate
peers has many benefits. First, the disconnect of a server peer only causes temporary loss of
a single sub-stream, which has limited impact on received video quality. Secondly, each substream has a rate much lower than the total rate of the video, thus reducing the required
uplink capacity at each peer. Thirdly, streaming from multiple peers helps balance the load
among the serving peers. Finally, from the video publisher’s perspective, it is not desirable to
42
.
.
.
.
.
store an entire video on. any one peer, to prevent the peer from having illegal access to the
video.
.
.
We will study two classes
. of systems: systems which use multiple description coding
(MDC) in which all sub-streams (called descriptions) have equal importance; and systems
which use layered coding, in which the sub-streams (called layers) have varying importance.
The design of both classes of systems has five interacting components: 1) video coding; 2)
sub-stream placement; 3) admission control; 4) sub-stream server selection; and 5) substream delivery. These components must be designed jointly to maximize the number of
streaming sessions that can be supported simultaneously while guaranteeing the video
quality at each receiving client is above a certain target.
Participating Faculty: Shivendra Panwar (panwar@catt.poly.edu) (ECE), Keith
Ross (ross@poly.edu) (CIS), and Yao Wang (yao@vision.poly.edu) (ECE)
Funding sources: National Science Foundation, CATT
Website: http://eeweb.poly.edu/p2p/
43
.
.
.
.
.
.
Video Transport
over Wireless Ad Hoc Networks
.
.
.
This project aims to develop techniques that enable real-time video communications over
mobile ad-hoc networks, in which there is no fixed infrastructure. Rather, nodes join and
leave the network often. Due to mobility, the network undergoes frequent topological
reconfigurations. Thus, links are continuously established and broken. Due to the wireless
transmission medium, the quality of links further fluctuates because of channel fading
phenomena. These factors make supporting video traffic over ad-hoc networks a very
challenging task.
To overcome the inherent unreliability of adhoc networks, we propose to combine
multistream source coding and multipath transport. The general architecture of the proposed
system is illustrated below. A multipath routing layer sets up multiple paths between the
source and destination. The transport layer continuously monitors path quality parameters
and returns such information to the sender. Based on the path quality, the encoder generates
multiple substreams. Packets from the substreams are then dispersed by the traffic allocator
among the available paths. At the receiver, packets arriving from all the paths are put into a
resequencing buffer where they are reassembled into substreams after a preset playout delay.
Some or all the packets assigned to a path may be lost or overdue. Finally, the decoder
reconstructs a video sequence from the received packets from all substreams.
We have proposed and evaluated several multi-stream coding and transport schemes. The
performance of these schemes are evaluated via extensive simulations using both Markov
channel models and OPNET Modeler. We also implemented an ad hoc multiple path video
streaming testbed using notebook computers and IEEE 802.11b cards. As part of this project,
we developed a new multiple description coding schemes. We also developed a new
multipath routing protocol and proposed it for consideration by the Internet standardization
body IETF.
44
.
.
.
.
. Shivendra S. Panwar (panwar@catt.poly.edu) and Yao
Participating faculty:
.
Wang (yao@vision.poly.edu)
.
.
.
Funding Sources: NSF and CATT
Website: http://128.238.38.41/video
[1] S. Mao, S. Lin, S. S. Panwar, Y. Wang, and E. Celebi. Video transport over ad hoc
networks: Multistream coding with multipath transport. IEEE Journal on Selected Areas in
Communications, 21(10):1721–1737, Dec. 2003. Winner of the The Communications
Society Leonard G. Abraham Prize Paper Award in the Field of Communications Systems,
2003.
[2] Y.Wang and S. Lin, “Error Resilient Video Coding Using Multiple Description Motion
Compensation," IEEE Trans. Circuits and Systems for Video Technology. vol. 12, pp. 438452, June 2002.
45
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.
.
.
.
.
.
.
.
III. Telecommunications and Wireless
46
.
.
.
.
.
.
OFDM Wireless
LAN
.
.
.
Future generation mobile radio systems must support a great variety of services including
those applications requiring high data rates. One of the difficulties in achieving higher data
rates is excessive inter-symbol interference (ISI) introduced by the multipath wireless
communications channel. One possible solution is
Orthogonal Frequency Division
Multiplexing (OFDM). In OFDM serial data with a high rate is first converted to many
parallel streams each of which operates at a much lower rate. By inserting a guard time in
each channel, OFDM can support high data rates with little or no ISI. The spectra of the
subcarriers are allowed to overlap each other to maximize spectral efficiency.
The objective of this study is to implement a high data rate (54 Mb/s) OFDM wireless LAN
transceiver using Field Programmable Gate Array (FPGA) technology. Practical
performance capabilities and limitations will be determined. Analytical and computer
simulation studies will be conducted to determine Bit Error Rate performance.
The 802.11a OFDM wireless transmitter baseband processor has been designed. The VHDL
code has been written, and the simulation is now complete. It consists of 48 subcarriers each
modulated with 64 QAM to achieve a data rate of 54 Mb/s.
The baseband processor was implemented using an FPGA from Xilinx using the Very High
Speed Integrated Circuit (VHSIC) Hardware Description Language (VHDL). The baseband
receiver module VHDL code is also complete.
Simulation is in progress. After the simulation is verified, the RF front end design
begin.
Key-words: Orthogonal Frequency Division Multiplexing
Programmable Gate Array (FPGA), inter-symbol interference.
(OFDM),
will
Field
Participating Faculty: Frank Cassara (cassara@rama.poly.edu)
[1] Y-S Choi, P. Voltz, F. Cassara, On Channel Estimation and Detection for Multicarrier
Signals in Fast and Selective Rayleigh Fading Channels, IEEE Transactions on
Communications, Vol. 49, No. 8, August 2001.
[2] Y-S Choi, P. Voltz, F. Cassara, ML Estimation of Carrier Frequency Offset for
Multicarrier Signals in Rayleigh Fading Channels, Vol. 50, No. 2, March 2001.
47
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.
.
.
.
.
Cyber Security
Processor (CYSEP)
.
.
As the need for cost-effective,
ubiquitous secure communications continue to rise,
. to virtual private
corporations are turning
networks (VPNs) to eliminate expensive leased
lines to provide secure access of sensitive data for both intra and inter-organization
communications. As these institutions increasingly rely on web-based applications to
interface with customers, clients and business partners alike, they also place their sensitive
information and databases at greater risk of attack at the web application level. Conventional
solutions such as firewalls, VPN gateways and intrusion detection systems do not
completely solve the problem. They only analyze packet headers and cannot detect threats
embedded in network content, because they lack the processing power necessary to analyze
content in real time to detect viruses, worms, or inappropriate content – and therefore leave
the network edge open to a wide range of costly, content-borne threats.
We plan to enhance the network security in four aspects by implementing a Cyber-Security
Processor (CYSEP) to perform the functions of firewall/intrusion detection,
encryption/decryption, authentication, and distributed denial of service (DDoS) attack
protection, as shown in the Figure 1. The CYSEP, consisting of four engines, will be
implemented on application-specific integrated circuits (ASIC) with the state-of-art CMOS
0.18-mircron technology and expected to operate at 10 Gbps or higher.
Cyber-Security
Processor
To Memory
Encryption
Decryption
Engine
Authentication
Authorization
Engine
DDoS
Engine
To NP or
End Sy stem
SPI 4.2 Interface
Firew all &
Intrusion
Detection
Engine
SPI 4.2 Interface
To Framer
Memory Controller
PCI BUS Controller
To PCI Bus
Figure 1. Cyber-Security Processor (CYSEP) architecture

The firewall and intrusion detection engine (FIDE) detects and prevents possible attacks
from outside or inside of an enterprise network. The FIDE implements the functions of
finite automata based signature detection and packet classification at 10 Gbps.
 The encryption/decryption engine implements the message confidentiality primitives
necessary to establish VPN over the public Internet. Our preliminary fieldprogrammable-gate-array (FPGA) implementation of the optimized Advanced
Encryption Standard (AES) block and stream cipher operates at about 5 Gbps. We expect
to achieve 10 Gbps or higher throughput with ASIC implementation.
 The authentication and authorization engine implements the message integrity primitive
necessary to establish VPNs. The engine will implement a universal hash function based
Message Authentication Code with extremely small collision probability. Based on the
throughput estimates obtained from our synthesis experiments, we expect the throughput
for the ASIC implementation to be >70 Gbps.
48
.
.
.
.
. engine uses our proposed PacketScore scheme, which determines
 The DDoS protection
.
the legitimacy of a suspicious packet according to the score assigned to the packet. By
taking a score-based. filtering approach, we avoid the problems of conventional binary
. achieve great scalability in speed (e.g., 10 Gbps or higher) and the
rule-based filtering and
number of potential .victims.
Massive parallelism and pipelining technique is to be employed in the ASIC to achieve the
10 Gbps wire-speed operation. The CYSEP can be deployed at various places in the
network, e.g., at high-performance end-systems, data centers, enterprise networks, and the
Internet service provider’s backbone network to enhance cyber security and to increase
bandwidth efficiency of the network, as shown in Figure 2.
Figure 2. Deployment of CYSEP within the networks
Key-words: Network Security, Cryptograph, Intrusion Detection, Denial of Service.
Participating Faculty: H. Jonathan Chao (chao@poly.edu) and Ramesh Karri
(ramesh@india.poly.edu)
Website: http://eeweb.poly.edu/~chao/research/cysep.html
[1] M. C. Chuah, W. Lau, Y. Kim, and H. J. Chao, Transient Performance of PacketScore
for blocking DDoS attack, IEEE ICC 2004, Paris, June 2004.
[2] W. Lau, M. C. Chuah, Y. Kim, and H. J. Chao, Distributed architecture for statistical
overload control against distributed denial of service attacks, patent application filed on Nov.
26, 2003.
[3] Y. Kim, W. Lau, M. C. Chuah, and H. J. Chao, PacketScore: statistical-based overload
control against distributed denial-of-service, IEEE Proc. INFOCOM, Hong Kong, March
2004.
[4] Y. Kim, J.-Y. Jo, H. J. Chao, and F. L. Merat, High-speed router filter for blocking TCP
flooding under distributed denial of service attack, International Performance, Computing
and Communications Conference, Phoenix, Arizona, April 2003.
49
.
.
.
.
.
Multi-Stage.. Buffered Packet Switches
.
The Internet has become a fundamental driving force for a variety of information
.
technologies due to its ever-growing ability to handle traffic, its ubiquitousness, and the
services. New applications, such as sensor fusion, bio-informatics, grid computation,
global data storage, and on-line video applications, are emerging. Common among these
applications is their demand for a huge amount of bandwidth and a global packet
switching infrastructure. In contrast to the success in increasing the raw bandwidth for
terabit transmission capability using dense wavelength division multiplexing (DWDM)
technology toward the end of last century, today’s electronic router technology may
soon exhaust its capacity of a few terabit/s. To find a cost-effective way to build a
router with a few tens of terabit or even petabit capacity will be the key to the
continuing success of the next-generation Internet.
Many researchers have attempted to build high-speed large-capacity packet switches,
which are often categorized into different architectures based on the placement of
buffers, e.g., input-buffered, output-buffered, crosspoint-buffered, internal buffered, and
combined input-output buffered. Reference [1] addresses the basics, theories,
architectures, and technologies to implement ATM switches, IP routers, and optical
packet switches. One of promising architectures is a multi-stage buffered switch as
shown in the figure below. It is very scalable and doesn’t require any arbitration if a
flow control scheme is implemented between the stages.
p
n
p
…
n
p
TME(0)
…
…
m
p
…
…
k
OM(k-1)
mxn
n
…
m
OM(0)
mxn
…
…
k
…
…
CM(m-1)
kxk
m
…
k
CM(0)
kxk
…
m
…
…
…
IM(k-1)
nxm
k
…
n
k
…
p
m
IM(0)
nxm
…
…
…
TMI(n-1)
…
TMI(0)
n
TME(n-1)
Plane(0)
p
p
…
TME(N-n)
…
…
n
…
…
OM(k-1)
mxn
…
m
OM(0)
mxn
…
…
k
…
…
CM(m-1)
kxk
…
k
CM(0)
kxk
…
m
…
…
…
IM(k-1)
nxm
…
n
k
…
p
m
IM(0)
nxm
…
…
…
TMI(N-1)
n
…
TMI(N-n)
TME(N-1)
Plane(p-1)
One of the challenges for the multi-stage buffered switches is to resolve packet out-ofsequence problem because packets sent to different paths may experience different
queuing delays. One way to avoid the packet out-of-sequence problem in the buffered
multi-path switch fabric is to re-sequence packets at the output port. This re-sequencing
scheme has been studied in many literatures. Another way to avoid the out-of-sequence
problem is to send all packets belong to the same flow to the same path. This idea is
attractive in the sense that the out-of-sequence problem is only counted for the packets
belong to the same flow.
One problem of the static hashing scheme is the load imbalance. Since each flow may
have different bandwidth, it is possible that one path is more congested than the other
path. This creates the complexity of choosing proper paths to route packets from an
50
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.
.
.
.
input port to an output. port. If paths are not properly chosen, the probability of internal
block in the middle stage
. increases, adversely impacting switch performance. In order
to make the loads of .all paths comparable, we propose to use a dynamic hashing. In
dynamic hashing, the .input port maintains outstanding number of packets in the switch
fabric for each flow. If there is an outstanding packet in the switch fabric, all the
following packets belonging to the flow must be sent to the same path with the previous
packet. Otherwise, they can be sent to any other path. Therefore, there is no need for
packet re-sequencing circuitry at the output port. This scheme is more attractive than the
re-sequencing scheme because the high-speed input port may have hundreds of
thousands flows and the number of paths is only a few hundreds.
We have prototyped a 16x16 multi-stage buffered switch with line rate of 10 Gbit/s, as
shown below. We are experimenting different load-balancing schemes by using the
FGPA-based reconfigurable switch fabric.
Key-words: packet switches, Clos network, packet scheduling.
Participating Faculty: H. Jonathan Chao (chao@poly.edu)
Website: http://eeweb.poly.edu/~chao/research/
[1] Broadband Packet Switching Technologies – A Practical Guide to ATM Switches and IP Routers,
H. J. Chao, C. Lam, and E. Oki, John Wiley & Sons, Inc, Sep. 2001.
[2] H. J. Chao, Z. Jing, and K. Deng, PetaStar: A petabit photonic packet switch, in IEEE Journal on
Selected Areas in Communications (JSAC), Special Issue on High-Performance Optical/Electronic
Switches/Routers for High-Speed Internet, vol. 21, no. 7, pp. 1096-1112, Sep. 2003.
[3] R. Rojas-Cessa, E. Oki, and H. J. Chao, Concurrent fault detection for a multiple-plane packet
switch, in IEEE/ACM Trans. on Networking, vol. 11, no. 4, pp. 616-627, Aug. 2003.
[4] E. Oki, Z. Jing, R. Rojas-Cessa, and H J. Chao, Concurrent round-robin-based dispatching
schemes for Clos-network switches, in IEEE/ACM Trans. on Networking, vol. 10, no. 6, pp. 830-844,
Dec. 2002.
[5] H. J. Chao, Next generation routers, invited paper, IEEE Proceeding, vol. 90, no. 9, pp. 15181558, Sep. 2002.
[6] E. Oki, R. Rojas-Cessa, and H J. Chao, A pipeline-based maximal-sized matching scheme for
high-speed input-buffered switches, in IEICE Trans. Commun, vol. E85-B, no. 7, pp. 1302-1311, July
2002.
[7] J. S. Park and H. J. Chao, Design and analysis of enhanced Abacus switch, Computer
Communications, vol. 25, no. 6, pp. 577 – 589, April 2002.
[8] H. J. Chao and T. S. Wang, An optical interconnection network for terabit IP routers, IEEE Journal
of Lightwave Technology, vol. 18, no. 12, pp. 2095-2112, Dec. 2000.
51
.
.
.
.
.
. Wireless Communications:
Cooperative
.
. Principles
Fundamental
.
Most existing wireless systems, such as 802.11 or 3G cellular, comprise a number of
independent nodes or users that are in contact with an access point (base station). Adhoc (multihop) networks, on the other hand, transmit information from the source node
to the destination via relaying nodes. The standard technique is for the nodes to only
process signals coming from the previous node in the route. Cooperative networking
presents a different approach, where two or more active users in the network share their
information to jointly transmit their messages, either at different times or
simultaneously, with the objective of gaining greater reliability and efficiency than they
could obtain individually.
The idea behind cooperative communication rests on the observation that in a wireless
environment, the signal transmitted by the source node is “overheard" by other nodes,
which we call partners. The partners process and re-transmit the signals they receive.
The destination combines the signals coming from the source and the partners, thereby
creating spatial diversity. This user cooperation diversity (a term coined by our group
[1], [2]) or cooperative diversity, can be used on top of existing diversity schemes
already present in the nodes. We note that the spatial diversity arising from cooperation
is not exploited in the current implementation of cellular, wireless LAN or ad-hoc
systems; only one copy of the signal, whether it comes from the mobile directly or from
a relay, is processed at the destination. In addition, we envision a situation in which all
partners take turns in creating spatial diversity for each other, turning the cooperative
scheme into a virtual transmit antenna array. Further benefits of this virtual array
include higher throughput and extended battery life for nodes, leading to a higher
network life in the case of ad-hoc networks. However, the elements of this array are not
co-located, they belong to different terminals which are connected via noisy channels.
Hence one has to carefully study the conditions under which cooperation is useful and
investigate practical schemes to get the desired benefits.
This project considers an information theoretic study of cooperative communication
systems. Our capacity and outage analysis illustrates benefits of cooperation in terms of
both data rates and robustness to channel variations [1], [2]. The research plan includes
a study of cooperative techniques when multiple terminals are involved. We study the
diversity gains of using multiple relays with various processing capabilities [3]. We
illustrate how the overall robustness of the system can be maximized by forming a
virtual transmit and receive antenna array [4]. We also consider cooperative relaying
strategies for multiple transmitters (multiple access channel with relays) or multiple
receivers (broadcast channel with relays).
52
.
.
.
.
. Elza Erkip (elza@poly.edu)
Participating Faculty:
.
.
Website: http://eeweb.poly.edu/~elza/
.
.
Funding Sources: NSF, CATT, WICAT
[1] A. Sendonaris, E. Erkip, and B. Aazhang. User cooperation diversity–Part I: System
description. IEEE Transactions on Communications, 51(11):1927–1938, Nov. 2003.
[2] A. Sendonaris, E. Erkip, and B. Aazhang. User cooperation diversity–Part II:
Implementation aspects and performance analysis. IEEE Transactions on Communications,
51(11):1939–1948, Nov. 2003.
[3] M. Yuksel and E. Erkip. Diversity in relaying protocols with amplify and forward. In
Proceedings of 2003 GLOBECOM Communication Theory Symposium, San Francisco,
December 2003.
[4] M. Yuksel and E. Erkip. Diversity gains and clustering in wireless relaying. In
Proceedings of 2004 International Symposium on Information Theory, Chicago, June 2004.
53
.
.
.
.
.
. Coding for Wireless Networks
Cooperative
.
.
.
User cooperation represents an effective way of introducing diversity in wireless networks.
Spatial diversity gains are obtained through the cooperative use of antennas belonging to
several nodes. We design and analyze the performance of channel codes that are capable of
achieving the full diversity provided by user cooperation. The codes provide substantial
diversity and coding gains over the non-cooperative case, even when the inter-user channel
is faded and noisy. The work extends to cooperative space-time codes designed to achieve
cooperation among nodes with different number of antennas. The codes use the principle of
overlays in time and space, and ensure that cooperation takes place as often as possible. We
illustrate that cooperative coding greatly reduces the error rates of all nodes involved, in a
variety of cooperation scenarios.
Key-words: diversity methods, error-correction coding, fading channels, multipleinput/multiple-output (MIMO) systems.
Participating Faculty: Andrej Stefanov (stefanov@poly.edu), Elza Erkip
(elza@poly.edu)
Websites: http://eeweb1.poly.edu/stefanov/, http://eeweb.poly.edu/~elza/
[1] A. Stefanov and E. Erkip, Cooperative Coding for Wireless Networks, IEEE
Transactions on Communications, vol. 52, No. 9, pp. 147—1476, September 2004.
[2] A. Stefanov and E. Erkip, Cooperative Space-Time Coding for Wireless Networks,
Proceedings of IEEE Information Theory Workshop, pp. 50-53, La Sorbonne, Paris, France,
April 2003.
[3] A. Stefanov and E. Erkip, On the Performance Analysis of Cooperative Space-Time
Coded Systems, Proceedings of IEEE Wireless Communications and Networking
Conference (WCNC), pp. 729-734, New Orleans, Louisiana, March 2003.
[4] A. Stefanov and E. Erkip, Cooperative Coding Theory and Applications, 32nd Annual
IEEE Communication Theory Workshop, Mesa, Arizona, April 2003.
[5] A. Stefanov and E. Erkip, Cooperative Information Transmission in Wireless Networks,
Proceedings of 2nd IEEE Asian-European Workshop on Concepts in Information Theory,
pp. 90-93, Breisach, Germany, June 2002.
54
.
.
.
.
.
. Source and Channel Coding
Cooperative
.
.
.
Current and next generations of wireless devices and services are substantially different
than the original cellular phones which could only carry voice signals. Third/fourth
generation cellular and wireless local area networks are designed to support data
services, image and video communications as well as voice. Multimedia signals require
higher data rates and larger bandwidths than their voice counterparts. This necessitates a
more efficient use of already scarce radio resources. Furthermore, guaranteeing a
desired level of signal quality for image and video is especially difficult given that the
wireless channel is unreliable and compressed audio and video streams are very
sensitive to transmission errors.
In order to provide robust wireless multimedia communications, this research uses
cooperative communication techniques along with jointly optimized source
compression and channel coding strategies. Cooperation of wireless terminals is
achieved by overhearing other terminal's signals and retransmitting towards the desired
destination. This provides signal diversity and enables robust source-to-destination
routes which can adapt to changes in the wireless environment. In order to establish the
theory and practice of cooperative source and channel coding, the research plan consists
of three interrelated components: Information theory of source channel cooperation;
design of cooperative source and channel coding techniques with numerical/simulation
studies to jointly optimize the parameters; and application of these techniques to
wireless video transmission. Our initial results illustrate the benefits of layered
cooperation both for idealized and practical channel codes. Layered cooperation
improves the overall source distortion by providing higher reliability for important
source bits via cooperation [1], [2], [3].
Participating Faculty: Elza Erkip (elza@poly.edu), Yao Wang
(yao@vision.poly.edu)
Website: http://eeweb.poly.edu/~elza/, http://eeweb.poly.edu/~yao/
Funding Sources: NSF, Philips Research, CATT, WICAT
[1] D. Gunduz and E. Erkip. Joint source-channel cooperation: Diversity versus spectral
efficiency. In Proceedings of 2004 International Symposium on Information Theory,
Chicago, June 2004.
[2] X. Xu, Y. Wang and E. Erkip. Layered cooperation for wireless multimedia
communications. To appear, Proceedings of 2004 Picture Coding Symposium, San
Francisco, December 2004.
[3] X. Xu, D. Gunduz, E. Erkip and Y. Wang. Layered cooperative source and channel
coding. Submitted, 2005 ICC Multimedia Communication and Home Networking
Symposium, Seoul, Korea, May 2005.
55
.
.
.
.
.
. Regions and Partner Choice in
Cooperative
.
.
Coded Cooperative
Systems
.
Cooperation of mobiles provides signal diversity in wireless networks. See project
“Cooperative Wireless Communications: Fundamental Principles” for a detailed
description of the cooperation principle. Most work in the literature of cooperative
systems assumes that a cooperating partner is already chosen and investigates the details
of how cooperation should be carried out. However, it is also important to be able to
choose a partner among available candidates to maximize cooperation benefits for the
user or the whole system. Therefore, for a given cooperative protocol, it is desirable to
know exact conditions under which cooperation is useful, how much benefits can be
brought by cooperation and how the channel qualities of user-to-user and user-todestination links affect these benefits of cooperation.
In this project we consider a coded cooperative system as described in the project
“Cooperative Coding for Wireless Networks” and investigate the choice of partners to
minimize the error rates. We study the partner choice problem both in an asymptotic
regime when the received signal to noise ratios are high, and as a function of the
locations of users [1], [2]. Our results provide simple analytical tools that identify
locations of partner terminals, which we call “cooperative region,” such that if a source
terminal cooperates with someone in the cooperative region, it will observe a reduction
in the frame error rate with respect to no cooperation. Formulation of the cooperative
region enables us to limit the search region of good partners. We also develop
analytical tools that indicate the best partner from a set of available nodes that are all
inside the cooperative region. Using these results, cooperation decisions can be made
online without need of simulations or large look-up tables.
Participating Faculty: Elza Erkip (elza@poly.edu), Andrej Stefanov
(stefanov@poly.edu)
Website: http://eeweb.poly.edu/~elza/, http://eeweb1.poly.edu/stefanov/
Funding Sources: NSF, Philips Research, CATT, WICAT
[1] Z. Lin, E. Erkip and A. Stefanov, An asymptotic analysis on the performance of coded
cooperation systems. In Proceedings of 2004 Fall Vehicular Technology Conference, Los
Angeles, September 2004.
[2] Z. Lin, E. Erkip and A. Stefanov, Cooperative regions for coded cooperative systems. To
appear, Proceedings of 2004 GLOBECOM Communication Theory Symposium, Dallas,
December 2004.
56
.
.
.
.
.
. Feedback Design in Multiple
Preamble and
.
.
Antenna Systems
.
Most practical systems provide channel estimation at the receiver through preambles.
Furthermore, this information can be partially relayed to the transmitter through some
kind of feedback, in the form of ARQ or power control. However, it is not clear how
effective these ad-hoc channel estimation and feedback methods are in utilizing network
resources, what losses are incurred by imperfect or finite rate estimation and feedback
strategies and how the transmitter and receiver should be designed based on partial
channel estimation and feedback. These issues are especially relevant for multipleantenna systems where considerable gains can be achieved via feedback.
In this project we study achievable communication rates for some practical multi-antenna
preamble and feedback strategies. We provide analytical bounds on the outage probability,
the probability that communication at a particular information rate cannot be supported, for
finite rate feedback. We also illustrate how one can design good beamformers for multiple
transmit antennas based on this finite rate feedback.
Participating Faculty: Elza Erkip (elza@poly.edu)
Website: http://eeweb.poly.edu/~elza/
Funding Sources: NSF
[1] K. K. Mukkavilli, Sabharwal, E. Erkip and B. Aazhang. On beamforming with
finite rate feedback in multiple antenna systems. IEEE Transactions on Information
Theory, Special Issue on Space-Time Transmission, Reception, Coding and Signal
Design, vol. 49, no.10, pp. 2562-2579, October 2003.
[2] K. K. Mukkavilli, A. Sabharwal, E. Erkip and B. Aazhang. Beamformer design with
feedback rate constraints: Criteria and constructions. In Proceedings of 2003
International Symposium on Information Theory, Yokohoma, Japan, July 2003.
[3] K. K. Mukkavilli, A. Sabharwal, E. Erkip and B. Aazhang. Performance limits on
beamforming with finite rate feedback for multiple antenna systems. In Proceedings of
Thirty Sixth Annual Asilomar Conference on Signals, Systems and Computers, Pacific
Grove, California, November 2002.
[4] A. Sabharwal, E. Erkip and B. Aazhang. On channel state information in multiple
antenna block fading channels. In Proceedings of 2000 International Symposium on
Information Theory and its Applications, pp. 116-119, Honolulu, Hawaii, November
2000.
57
.
.
.
.
.
.
Radio Resource
Management in
.
.
Cellular Communications
.
The quality and efficiency of Wireless Internet communications depend on a large number
of design parameters and operational variables. In the 1990s, researchers and system
designers produced new theories and practical algorithms that maximize the capacity of
cellular systems carrying telephone conversations. Anticipating rapid growth in the volume
and diversity of data traffic in a Wireless Internet, this project research focuses on issues
directly related to efficient multimedia wireless communications.
Emerging wireless communications systems adapt their operating parameters to changing
channel conditions. This cluster of projects derives principles for designing wireless systems
and adapting them to provide optimum performance as conditions change. The overall
theme is allocating scarce radio resources by adjusting the transmission rates and radiated
power levels of terminals sharing the same radio channels.
Because the issues are complex we pursue a “divide-and-conquer” approach, with separate
studies looking at pieces of the overall problem. One study began with a noise-limited
system and considered the effect on throughput of three design parameters: binary
transmission rate, packet size, and the amount of forward error correction coding.
Later work provides guidance on how to adapt a wireless communications system to a wide
range of transmission conditions. When conditions are very good throughput is optimum
with multi-level modulation and no forward error correction. As the conditions deteriorate,
the number of modulation levels should decrease. Under poor conditions it is best to use
binary modulation and error correcting codes. The quantitative results of the study can be
used to match transmission conditions to changing locations of wireless terminals.
Other research focuses on data transmission from a collection of CDMA terminals to a
single base station. The CDMA studies address two different optimization criteria: aggregate
weighted throughput of the base station and the battery life of the terminals. They include
several different optimization studies distinguished by the constraints on the transmission
rate and transmission power of each terminal.
Key-words: Cellular Communications; Power Control; Rate Adaptation: CDMA
58
.
.
.
.
.
Participating Faculty:
. David Goodman (goodman@duke.poly.edu)
.
. NSF and WICAT
Funding Sources:
.
Website: http://eeweb.poly.edu/dgoodman/
[1] Rodriguez, V. An Analytical Foundation for Resource Management in Wireless
Communications, IEEE Globecom, Vol. 2, pp. 898-902, San Francisco, December,
2003.
[2] Rodriguez, V., Resource Management for Scalably Encoded Information: The Case
of Image Transmission Over Wireless Networks, IEEE ICME, Vol. 1, pp. 813-6,
Baltimore, July 7-09, 2003
[3] Rodriguez, V., D.J. Goodman, and Y. Wang, Optimal Coding Rate and Power
Allocation for the Streaming of Scalably Encoded Video Over a Wireless Link, IEEE
ICASSP, Montreal, May 17-21, 2004.
[4] Rodriguez, V., and D.J. Goodman, Power and Data Rate Assignment for Maximal
Weighted Throughput in 3G CDMA, IEEE WCNC, Vol.1, pp. 525-31, New Orleans,
March 16-20, 2003.
[5] P. Orenstein, D. J. Goodman, Z. Marantz, and V. Rodriguez, Effects of Additive Noise
on The Throughput of CDMA Data Communications, IEEE International Conference on
Communications (ICC) 2004, Paris, 2004.
[6] V. Rodriguez, D. J. Goodman, and Z. Marantz, Power and Data Rate Assignment for
Maximal Weighted Throughput in 3G CDMA: A Global Solution with Two Classes of
Users, IEEE Wireless Communications & Networking Conference (WCNC), Atlanta,
Georgia, March 21-25, 2004
[7] P. Orenstein, D. J. Goodman, and Z. Marantz, Maximizing the throughput of CDMA
Data Communications through joint admission and power control, 38th Conference on
Information Sciences and Systems (CISS) 2004, Princeton, NJ, March 16th-18th, 2004.
[8] D. J. Goodman, Z. Marantz, P. Orenstein, and V. Rodriguez, Maximizing The
Throughput of CDMA Data Communications, IEEE 58th Vehicular Technology Conference
(VTC), Orlando, FL, October 6-9, 2003.
59
.
.
.
.
.
Capacity of a. CDMA Base Station Receiving Real.
Time Media Signals
and Data Files
.
.
In a single cell of a CDMA system, some terminals transmit real-time media signals, such as
voice or video, and other terminals transmit data signals to the same base station. Each media
terminal has a fixed bit rate and needs to be received without delay and with a signal-tointerference ratio that exceeds a given minimum. The data terminals accept more delay than
media terminals in exchange for error free information transfer. They retransmit packets
received in error and adapt their transmission rates and transmitter power levels to maximize
the aggregate throughput of the base station.
Theoretical work simultaneously optimizes the packet size, binary transmission rates and
transmitter power levels of the data terminals. The results include performance bounds of the
system indicating the tradeoff between number of media terminals, media signal-tointerference ratio, number of data terminals, and data transmission rates. The work also
indicates the conditions in which it is better for the data terminals to transmit simultaneously
and the conditions that call for time-division scheduling of data transmissions.
Key-words: Cellular communications, multimedia, power control, rate adaptation
Participating Faculty: David Goodman (goodman@duke.poly.edu)
Funding Sources: NSF and WICAT
Website: http://eeweb.poly.edu/dgoodman/
Sangwook Suh, Resource Allocation and Hybrid TDMA/CDMA Scheme for the Uplink Of
Media/Data Wireless Systems, Master of Science Thesis, Polytechnic University, November,
2004.
60
.
.
.
.
.
.
Power Efficient
Multimedia Wireless
.
.
Communications
.
An important lesson of cellular telephone communications is that effective management of
radio resources, including transmitter power and channel bandwidth, is essential to the
quality and efficiency of a network and to the utility of subscriber equipment. The theory and
algorithms for radio resource management were first confined to telephone communications.
Later work showed that efficient power control algorithms for cellular data transmission
differ from those devised for telephony. The radio resource management problem becomes
even more complex when we anticipate networks that simultaneously carry a variety of
information types. Our research focuses on managing radio resources in multimedia wireless
networks with an emphasis on power efficiency.
As video transmission is integrated into wireless communication systems, the theory of
power control should be expanded to consider both signal processing power and
transmission power when designing new algorithms, since video coding can be a significant
drain on the battery of a portable wireless terminal.
This project examines the interaction of signal processing and radio transmission in the
design of algorithms for managing power and bandwidth utilization in multimedia wireless
networks. Initial research focused on a single portable terminal transmitting video signals to
a cellular base station. The research combines theory of source coding and radio
transmission, models of distortion due to source coding and channel errors in H.263 video
coders, and measurements of power dissipation in equipment performing video coding.
Initial results show that the optimum amount of video compression depends on the distance
between the terminal and the base station. To avoid using excessive transmitter power,
terminals far from a base station should employ more video compression (at the expense of
additional signal processing power consumption) than terminals near a base station.
Subsequent work expands the studies of a single terminal to consider the mutual interference
of several terminals, all transmitting video signals to the same CDMA base station. Work in
progress considers a network in which some terminals are transmitting video signals and
others are transmitting data to the base station.
Key-words: Cellular communications, power control, video compression
61
.
.
.
.
. Elza Erip (erkip@poly.edu), David
Participating Faculty:
.
(goodman@duke.poly.edu)
and Yao Wang (yao@vision.poly.edu)
.
.
Funding Sources: NSF
. and WICAT
Goodman
Website: http://eeweb.poly.edu/dream-it/
[1] Xiaoan Lu, Yao Wang, Elza Erkip and David Goodman, Minimize the Total Power
Consumption for Multiuser Video Transmission over CDMA Wireless Network: a Two-step
Approach, to be presented at 2005 International Conference on Acoustics Speech and Signal
Processing (ICASSP2005).
[2] Xiaoan Lu, David Goodman, Yao Wang and Elza Erkip, Complexity-bounded Power
Control in Video Transmission over a CDMA Wireless Network, To be presented at IEEE
Globecom 2004 Conference.
[3] Xiaoan Lu, Yao Wang, Elza Erkip and David Goodman, Power Optimization of Source
Encoding and Radio Transmission in Multiuser CDMA Systems, in Proceedings of 2004
International Conference on Communications (ICC), Vol. 5, pp. 3106-3110, June, 2004.
[4] Xiaoan Lu, Thierry Fernaine, Yao Wang, Modelling Power Consumption for H.263
Video Coding, in Proceedings of IEEE International Symposium on Circuits and Systems
(ISCAS), Vol. 2, pp. 77-80, 2004.
[5] Xiaoan Lu, Elza Erkip, Yao Wang and David Goodman, Power efficient multimedia
communication over wireless channels, IEEE Journal on Selected Areas on
Communications, Special Issue on Recent Advances in Wireless Multimedia, Vol. 21, No.
10, pp. 1738-1751, Dec., 2003.
[6] Xiaoan Lu, Yao Wang and Elza Erkip, Power efficient H.263 video transmission over
wireless channels, in Proceedings of 2002 International Conference on Image Processing
(ICIP), Vol. 1, pp. 533-536, September 2002.
[7] Elza Erkip, Xiaoan Lu, Yao Wang, David Goodman, Total power optimization for
wireless multimedia communication, in System Level Power Optimization for Wireless
Multimedia Communication: Power Aware Computing, edited by R. Karri and D. Goodman,
Chapter 1, Kluwer Academic Publishers, 2002.
[8] Elza Erkip, Yao Wang, David Goodman, Yuantao Wu and Xiaoan Lu, Energy efficient
coding and transmission, in Proceedings of IEEE Vehicular Technology Conference (VTC),
Vol. 2, pp. 1444-1448, Spring 2001, May 2001.
62
.
.
.
.
.
.
Network X-ities:
Foundations and
.
.
Applications
.
Given society's increasing reliance on communication networks such as the Internet, it is
becoming increasingly important that these networks not only provide good performance, but
do so in the face of a complex, uncertain, error-prone, and ever-changing environment. The
need for such robust network operation leads to a set of design considerations that we refer to
as the network X-ities (since they all end in ``ity''): non-fragility, manageability, diagnosability,
optimizability, scalability, and evolvability. Although these X-ities are crucially important in
designing and analyzing robust networks and protocols, they often lack theoretical foundations,
quantitative frameworks, or even well-defined metrics and meaning. The goal of this research
project is to begin to build a solid, quantitative foundation for explicitly considering the X-ities
in the design and analysis of network architectures and protocols. We do so by considering a
number of specific problems, broadly in the area of routing protocols, that allow us to
concretely address several of the X-ities and to begin to draw larger lessons from
commonalities among the problems studied. We also plan to apply our results in the context of
two ongoing system-building projects to demonstrate the value of our research in guiding
design decisions in a practical setting.
In studying non-fragility---the goal of operating a network under a wide range of conditions--we quantify this X-ity in the routing context in terms of routing stability, and the trade-off in
data-plane performance between the case in which routing is narrowly optimized (but may
provide catastrophically bad performance when operating outside of normal operating
conditions) and the case in which it is optimized to perform well over a wide range of operating
conditions. We focus on specific problems posed by various interacting layers of control (e.g.,
overlay/underlay routing, transport/network layer, intra/inter-domain routing) and uncertainty
(whether in traffic demands or as a result of element failure) in the operating environment. In
studying manageability---the ability for network operators to easily configure routing protocols,
diagnose (and fix) persistent problems, and control the evolution of the network infrastructure--we consider challenges posed by couplings between intra-domain routing and egress-point
selection, root cause identification for routing changes and the trade-off between routing
protocol overhead and diagnostic precision, and optimally deploying a network's physical
infrastructure over a multi-step time horizon. Finally, in the area of scalability, we consider the
trade-offs between a routing protocol's scalability and the resulting data-plane performance, as
well as techniques that can improve scalability with a minimal effect on performance.
Participating Faculty: Yong Liu (yongliu@duke.poly.edu)
63
.
.
.
.
.
Funding Sources:
. National Science Foundation
.
.
Website: http://eeweb.poly.edu/faculty/yongliu
.
[1] Chun Zhang, Zihui Ge, Jim Kurose, Yong Liu, and Don Towsley, "Optimal Routing
with Multiple Traffic Matrices: Tradeoff between Average Case and Worst Case
Performance", in the 13th IEEE International Conference on Network Protocols
(ICNP'2005)
[2] Chun Zhang, Yong Liu, Weibo Gong, Jim Kurose, Robert Moll and Don Towsley, "On
Optimal Routing with Multiple Traffic Matrices", in the Proceedings of IEEE Conference on
Computer and Communications (INFOCOM) 2005。
64
.
.
.
.
.
. Design of Overlay and PeerAnalysis and
.
.
Peer Networks
.
Application-level networks, such as overlay and peer-peer networks, have recently emerged as
a new paradigm for building distributed networked applications. Application-level control can
be used to overcome deficiencies or improve the performance of existing underlay networks.
For example, traditional network congestion control and routing schemes are generally unable
to fully utilize available network resources for high-bandwidth data transport. In [1], we
explored the flexibility of control at the application layer and proposed various applicationlevel data relay schemes to significantly improve network users' throughput by optimally
integrating application-level routing and transport-layer control. The proposed algorithms can
be easily adopted by data intensive applications, such as grid-computing and content
distribution, to achieve high speed data transport over wide area networks. We are also
investigating how to design a relay network to efficiently support new end-end applications,
such as voice-over-IP and video conferencing.
While overlay networks improve the performance perceived by overlay users, a fundamentally
important question is to understand how overlay networks might affect the operation of
underlay networks. In [2, 3], we systematically studied the interaction between the routing
optimization of overlay networks and underlay networks within a game theoretic framework,
and showed analytically that the selfish behavior of overlay networks can cause both huge cost
increases and oscillations in underlay networks. More importantly, we have also identified
cases where the interaction between the overlay and underlay networks is inefficient, i.e., both
overlay and underlay users suffer performance degradation. The analysis has been confirmed
by simulation studies. This work provides a starting point in the search for a rigorous and wellfounded understanding of the interaction between overlay routing and traffic engineering.
Various insights gained from this study can be used to guide the design of overlay/peer-peer
networks.
Participating Faculty: Yong Liu (yongliu@duke.poly.edu)
Website: http://eeweb.poly.edu/faculty/yongliu
65
.
.
.
.
.
[1] Yong Liu, Yu Gu, Honggang
Zhang, Weibo Gong and Don Towsley, "Application Level
.
Relay for High-bandwidth
. Data Transport'', recipient of the Best Paper Award in the First
Workshop on Networks. for Grid Applications (GridNets) , San Jose, October 2004.
.
[2] Yong Liu, Honggang Zhang, Weibo Gong and Don Towsley, "On the Interaction
Between Overlay Routing and Traffic Engineering'', in the Proceedings of IEEE Conference
on Computer and Communications (INFOCOM) 2005.
[3] Honggang Zhang, Yong Liu, Weibo Gong and Don Towsley, "On the Interaction
Between Overlay Routing and MPLS Traffic Engineering'', in the annual conference of
ACM Special Interest Group on Data Communications (SIGCOMM), Poster Session,
Portland, August 2004.
66
.
.
.
.
.
.
Network Measurement
and Monitoring
.
.
.
Network measurement provides the capabilities to better understand network conditions, and
therefore achieve better network control and management. Trace collection on a high speed
link requires a huge amount of storage. One solution is to compress packet headers to reduce
the storage requirement. In [1], we propose an information theoretic framework within which
to study the redundancy present in packet header traces. Packet level and flow level models are
developed that capture both temporal and spatial correlation present in packet headers, which
can be exploited for packet trace compression. Information theoretic bounds are established for
lossless packet header compression. Dependencies between the potential compression ratio and
network parameters, such as the average route length and average flow size are derived. Based
on the valuable insights obtained in this study, we are developing marginal and joint packet
trace compression algorithms. Their efficiency will be evaluated by comparing their
compression ratios on packet traces collected from our monitors with those predicted by our
models.
In addition to traffic characterization and network management, network measurement plays an
increasingly important role in network security. I am interested in the application of distributed
network monitoring for network intrusion detection. The pure volume of network traffic makes
it challenging to detect network anomalies from network traces. Adaptive multi-resolution
traffic sampling and efficient network trace compression and query schemes are promising
approaches to address this problem of scalability. The randomness inherent in networks, such
as packet loss and packet reordering, introduces ambiguity to network traces. Intelligent
attackers leverage existing protocols to hide their identities and fool network monitors. The
problem of efficiently combining traces collected at the network layer with application layer
analysis to catch attackers is an interesting direction to pursue. How one can efficiently
organize a network of monitors to maximize its capability to capture network wide phenomena
is important not only for network anomaly detection, but also for distributed network
monitoring as a whole. In [2], we proposed a information theoretic framework, within which to
study various problems of distributed network monitoring, such as network monitor placement
and measurement data fusion, etc.
Participating Faculty: Yong Liu (yongliu@duke.poly.edu)
Website: http://eeweb.poly.edu/faculty/yongliu
67
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.
. Jing Weng and Dennis Goeckel, "An Information Theoretic
[1] Yong Liu, Don Towsley,
. Compression", UMass CMPSCI Technical Report 05-03.
Approach to Network Trace
.
.
.
[2] Yong Liu, Don Towsley, Tao Ye and Jean Bolot, "An Information-theoretic Approach to
Network Monitoring and Measurement", in Internet Measurement Conference, 2005.
68
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Sensor Management
.
.
.
The project is to develop phenomenology and models for determining the effects of
electromagnetic interference and electromagnetic compatibility (EMI/EMC) on, and as a
result of adjunct ISR (intelligence, surveillance and reconnaissance) sensors for expanded
US Navy’s E2-C, EA-6B and EA-18G missions. The introduction of such adjunct ISR
sensors may interfere with existing and future systems (such as radar, jamming, signal
processing, and communications) as well as be incompatible with existing and future
EMI/EMC environments. This project will determine a range of possible interference effects
and potential design methods to mitigate these effects for current and future E2-C, EA-6B,
and EA-18G applications. So far, we have
 created a mathematical model to simulate the effects of electromagnetic radiation on the E2C aircraft. The model is used to identify and propose cost effective solutions to potential
electromagnetic radiation problems on the E-2C aircraft that could result from increased
sensor power levels.
 performed analysis to quantitatively describe the currents induced over the scattering
surfaces for EA-6B and EA-18G aircrafts.
 developed approaches to predict the width of the Fresnel zone for various surface wave
scattering paths and estimate the magnitude of the magnetic field intensity as a function of
incident RF power level.
 participated in Mockup EA-6B wing testing.
Key-Words: EMI, EMC
Participating Faculty: I-Tai Lu (itailu@rama.poly.edu)
[1] I-Tai Lu, “EMI and EMC Studies for Northrop Grumman’s Airplanes,” Northrop
Grumman report.
[2] I-Tai Lu, “Supplementary Results to the Joint Service Center Reports,” Northrop
Grumman report.
69
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Wireless Geolocation
.
.
.
The project is to develop localization algorithms using multiple range-based data (such as
time of arrival or time difference of arrival) or direction-based data (such of angle of arrival)
for determining target locations. The location estimates from different algorithms will be
combined using novel "Data Fusion" approaches. Currently, a Modified Asymptotic Linear
Solver is proposed to estimate emitter locations by solving the intersections of hyperbolas
defined by measured time differences of arrivals. The algorithm achieves simplicity and
computational efficiency by removing the nonlinearity inherited in hyperbolic localization
problems. Off-line parameter optimization is required to minimize the estimation error.
Simulation results have shown that performance of the proposed new algorithm is similar to
that of a Maximum-Likelihood Estimator in regions of interest.
Key Words: Geolocation, Data Fusion, Multilateration
Participating Faculty: I-Tai Lu (itailu@rama.poly.edu)
[1] HaoYun Wu and I-Tai Lu, "Asymptotic Linear Solver for Hyperbolic
Localization"submitted for possible publication in the IEEE Transactions on Wireless
Communications.
[2] HaoYun Wu and I-Tai Lu, "A Simple and Robust Linear Solver for Hyperbolic
Localization", submitted to IEEE Wireless Communications & Networking Conference,
New Oreland, 2005
70
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.
Fading Channel
Prediction with Multipath
.
.
Based Modeling
.
Adaptive transmit diversity and adaptive modulation and coding techniques are all showing
great promise as enhancements to Wideband CDMA cellular radio. The success of these
techniques however greatly depends on the availability of reliable channel state information
(CSI). Since this information is most accurately calculated at the receiver, future CSI
prediction must be used so that time is available to send results back to the transmitter.
Currently, it is indicated that reliable CSI prediction results may be achieve at up to
approximately one carrier wavelength. For a third generation WCDMA mobile traveling at
100 km/h, this leaves about 5 ms for CSI feedback and validity of channel model.
Enhancements in CSI prediction are required in order to achieve higher mobile speed
operation, efficient implementation and more reliable CSI. The work proposed here seeks to
demonstrate superior CSI estimation, tracking and prediction. Currently, a new method
using two Kalman filter’s is proposed to estimate and track both multichannel responses,
carrier frequency offset and autocorrelation coefficients for space-time code transmissions
over time-selective fading channels.
Key Words: Fading, Channel Estimation, Kalman Fiter
Participating Faculty: I-Tai Lu (itailu@rama.poly.edu)
[1] Hsin-Chang Wu and I-Tai Lu, 'Simultaneous Multichannel Tracking and Model
Adjustment using Two Kalman Filters for Space-Time Transmit Diversity' submitted to
IEEE Wireless Communications & Networking Conference, New Oreland, 2005
`
71
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.
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.
.
Designing..Medium Access Control for
. Networks
Cooperative
.
The wireless medium is a broadcast one by nature. Many nodes may overhear the
transmission. In the legacy IEEE 802.11 medium access control (MAC) protocols,
transmissions received by mobile stations other than the intended receiver are discarded. The
broadcast nature of the wireless channels is not fully utilized. Additionally, in legacy IEEE
802.11, transmission rates of different station can vary over a wide range (e.g., from 1 to 11
Mbps in IEEE 802.11b), the high rate stations have the same channel access probability as
the low rate stations, but in fact they obtain lower share of channel time than the low rate
stations. This not only degrades the throughput, but also causes serious fairness problems
because low data rate stations uses most of the channel time.
To exploit the broadcast nature of wireless channels, recent work on cooperative coding has
shown that additional “cooperative” nodes, which overhear the transmission from sender and
then participate in additional transmissions, can provide space diversity for the system. We
adopt these ideas to increase the throughput of a wireless network and designed a new MAC
protocol. In our proposed cooperative MAC protocol, instead of reducing the transmission
rate for the nodes near the edge, we facilitate low rate stations to transmit the data packet first
to an intermediate station and then to the destination, if this two-hop transmission approach
is faster than direct transmission.
Figure 1: Exchange of control and data packet
In our protocol, each station in the network needs to overhear the ongoing transmission by
other stations, from which they can discover their neighbors. When a station has data to
72
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.
.
.
.
transmit, it will choose.one station from the neighbor list, so that if a packet was sent to the
selected station first and. then relayed to the destination, this two hop transmission spends the
least transmission time.. We also introduced a new handshake message - HR (helper-ready)
in additional to the
. RTS (request-to-send), CTS (clear-to-send) and ACK
(acknowledgement) already in 802.11. An illustration of the exchange of control and data
packet is shown in Figure 1.
We validated our protocol using both analytical modeling and simulation. The results show
that cooperative MAC protocol can substantially enhance the network performance, in terms
of the achievable throughput and average delay experienced by the data packets. Besides, the
cooperative MAC improves the system fairness in the sense that it reduces the channel time
occupied by low rate stations. Last, but not the least, the protocol is designed such that only
minor software modification to the legacy MAC implementation is needed and backward
compatibility with the legacy IEEE 802.11 system is maintained.
Participating Faculty: Shivendra Panwar (panwar@poly.edu)
Website: http://catt.poly.edu/CATT/panwar.html
73
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.
.
.
.
Performance.. Evaluation of IEEE the 802.11e
.
Enhanced Distributed
Channel Access (EDCA)
.
The IEEE 802.11e enhanced distributed channel access (EDCA) protocol is designed to
enhance the QoS capability of wireless local area networks (WLAN). As shown below,
each station in EDCA can have multiple queues that buffer packets of different
priorities. A set of EDCA parameters, namely arbitration interframe space (AIFS),
minimum contention window size (CWMin) and maximum contention window size
(CWMax) is associated with each priority to differentiate the channel access.
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requirements of each priority. This is accomplished by modeling the performance impact of
all the major QoS-specific features (e.g., CWMin, CWMax, AIFS, internal collision
resolution) of the IEEE 802.11e EDCA mode.
As for future research, we will investigate the quality of service that upper layer applications
(e.g., VoIP) can receive, with the EDCA mechanism enabled at the MAC layer.
74
.
.
.
.
. Shivendra Panwar
Participating Faculty:
.
.
Website: http://catt.poly.edu/CATT/panwar.html
.
.
[1] Z. Tao, S.S. Panwar, An Analytical Model for IEEE 802.11e Enhanced Distributed
Coordination Function (EDCF), IEEE International Conference on Communications (ICC),
Paris, France, June 2004.
[2] Z. Tao, S.S. Panwar, An Analytical Model for the IEEE 802.11e EDCF, The 13th IEEE
Workshop on Local and Metropolitan Area Networks, Mill Valley, California, April 2004.
75
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.
High Performance
Stable Packet Switches
.
.
.
In this project, we consider the design of high performance packet switches. Switching
technology continues to be one of the bottlenecks in the development of broadband
networks. The source of this bottleneck is the mismatch between the data rates that can
be supported on fiber optic lines, which are doubling every year, and the semiconductor
based technology of switches, which are doubling only once every eighteen months. We
believe that once this bottleneck is cleared, multimedia applications will lead to another
wave of growth in traffic growth comparable to the earlier ones driven by email and
web traffic. In the mean time, in spite of this bottleneck, traffic continues to double
every year. Thus switching will reemerge as a key issue in the growth of the Internet.
Fixed-length switching technology is widely accepted as an approach to achieving high
switching efficiency for high-speed packet switches. Variable-length IP packets are
segmented into fixed-length “cells” at inputs and are reassembled at the outputs. Packet
switches based on Input Queuing (IQ) are desirable for high speed switching, since the
internal operation speed is only moderately higher than the input line speed. Virtual
Output Queuing (VOQ) is used to overcome the head-of-line (HOL) blocking
drawbacks and combine the advantages of an Input Queuing switch and an Output
Queuing switch. In a VOQ switch, each input maintains N queues, one for each output.
There are two approaches to resolve the output contention. One is to use matching
algorithms to schedule the input-output connections in each time slot. It is important to
achieve high performance by performing a suitable scheduling arbitration scheme in a
high speed packet switch. The other approach is using a load-balancing switch, where
two switch stages are used. Arrival traffic is load balanced by the first switch stage at
each input by sending cells cyclically to all the output ports. The second stage is used to
switch cells to the appropriate output port. No scheduler is used in a load-balancing
switch, but re-sequencing is needed at the output to restore packet order.
Most switches have been optimized for cell switching, not packet switching. This may
have been the right approach to designing ATM cell switches, but is clearly
inappropriate for the variable sized packets seen in today’s Internet. Internet switches
are rapidly supplanting ATM switches, this makes a significant difference. The optimal
VOQ cell switch, using the so far un-implementable maximum weight matching
(MWM) algorithm, turns out to have higher delay than HEiSLIP (our proposed low
complexity switch architecture), when packet delay is considered. Load balancing
switches have recently emerged as an alternative switch architecture. They have the
attractive feature of not requiring a centralized scheduler, unlike most VOQ switches,
and are therefore more scalable. However, they do suffer from large worst case resequencing delay. We have designed a load balancing switch, called the Byte-Focal
switch, which shows encouragingly low cell delay results. We will again consider the
packet delay performance instead of just cell delay. This is challenging because the
76
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.
.
.
. re-sequencing operations overlap in time. Also, we will test a
packet reassembly and
. basis of our previous research, that for the long range dependent
conjecture made on the
.
traffic characteristic of. the Internet, load balancing switches may have inherent traffic
shaping properties which
. lead to improved performance over competing switch
architectures. After testing the validity of our conjecture using Internet traffic traces, we
hope to uncover interesting switch design insights analogous to our above-mentioned
work on the difference between packet delay and cell delay for packet switches.
Participating Faculty: Shivendra Panwar (panwar@catt.poly.edu) and
H. Jonathan Chao (chao@poly.edu)
Website: http://eeweb.poly.edu/~chao/projects/nsf/nsf.html
Funding Sources: National Science Foundation, CATT
[1] Yihan Li, Shivendra Panwar and H. Jonathan Chao, "Exhaustive Service Matching
Algorithms for Input Queued Switches, 2004 Workshop on High Performance
Switching and Routing (HPSR 2004).
[2] Yihan Li, Shivendra Panwar and H. Jonathan Chao, Frame-based Matching
Algorithms for Optical Switches, 2003 Workshop on High Performance switching and
Routing (HPSR 2003), June 2003.
[3] Yihan Li, Shivendra Panwar and H. Jonathan Chao, Performance Analysis of a Dual
Round Robin Matching Switch with Exhaustive Service, IEEE GLOBECOM 2002.
[4] Yihan Li, Shivendra Panwar and H. Jonathan Chao, Performance Analysis of a Dual
Round Robin Matching Switch with Exhaustive Service, High-Speed Networking
Workshop (HSN 2002), June 2002.
[5] Yihan Li, Shivendra Panwar and H. Jonathan Chao, The Dual Round-Robin
Matching Switch with Exhaustive Service, 2002 Workshop on High Performance
Switching and Routing (HPSR 2002), pp. 58-63, May 2002.
[6] Yihan Li, Shivendra Panwar and H. Jonathan Chao, "On the Performance of a Dual
Round-Robin Switch," IEEE INFOCOM 2001, vol. 3, pp. 1688-1697, April 2001.
77
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.
.
.
.
. and Channel Coding for MIMO
Joint Source
.
.
Video Communications
.
The problem of efficient video communication over multiple-input/multiple-output (MIMO)
systems is of great significance due to the high capacity of the multiple antenna system. The
high data rates provided by the MIMO system can be traded-off with diversity gain by using
different channel coding schemes. Also, by using different video coding methods high
compression gain can be traded-off with error resilience gain. We consider the joint design
of source and channel codes for efficient transmission of video over the wireless channel. In
particular, we investigate which diversity level and which error resilient video coding
algorithm is the best option for a MIMO video system. The selection of the best video coder
and its coding redundancy depend on the available bandwidth and loss rate after channel
coding. Similarly, the selection of the best channel coder and its diversity level depend on
the video encoders compression efficiency and error resilience.
Key-words:
space-time coding, joint source and channel coding, multipleinput/multiple-output systems.
Participating Faculty: Andrej Stefanov (stefanov@poly.edu) and Yao Wang
(yao@vision.poly.edu)
Website: http://eeweb1.poly.edu/stefanov/, http://eeweb.poly.edu/~yao/
[1] S. Lin, A. Stefanov and Y. Wang, Joint Source and Space-Time Block Coding for
MIMO Video Communications, Proceedings of IEEE VTC-Fall, Los Angeles, California,
September 2004.
[2] S. Lin, A. Stefanov and Y. Wang, On Video Communications in MIMO Systems:
Channel Coding and Error Resilient Source Coding, Proceedings of 4th IEEE Signal
Processing Workshop on Signal Processing Advances in Wireless Communications
(SPAWC), pp. 653-657, Rome, Italy, June 2003.
78
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.
.
.
.
. Coding
Space-Time
.
.
.
The main challenge in achieving reliable communication in wireless systems lies in the
severe conditions that are encountered when transmitting information over the wireless
channel. The channel impairments such as multi-path fading, interference and noise can have
a deleterious impact on the system performance. Diversity techniques represent an effective
way to combat fading. One way to introduce diversity into the wireless system is by
deploying multiple transmit and receive antennas. In addition, recent information theoretic
results have demonstrated that the capacity of the system in the presence of quasi-static
Rayleigh fading increases linearly with the number of transmit antennas, as long as the
number of receive antennas is greater than or equal to the number of transmit antennas. To
exploit this promised capacity we consider the design and analyze the performance of both
space-time trellis codes and turbo coded modulation for multiple antenna systems. These
codes provide improved data rate while reducing the error rate when transmitting
information over the wireless channel.
Key-words: space-time coding, error-correcting coding, fading channels, multipleinput/multiple-output (MIMO) systems.
Participating Faculty: Andrej Stefanov (stefanov@poly.edu)
Website: http://eeweb1.poly.edu/stefanov/
[1] A. Stefanov and T. M. Duman, Turbo Coded Modulation for Systems with Transmit and
Receive Antenna Diversity over Block Fading Channels: System Model, Decoding
Approaches and Practical Considerations, IEEE Journal on Selected Areas in
Communications, Special Issue on The Turbo Principle: From Theory to Practice, vol. 19,
No. 5, pp. 958-968, May 2001.
[2] A. Stefanov and T. M. Duman, Performance Bounds for Turbo Coded Multiple Antenna
Systems, IEEE Journal on Selected Areas in Communications, Special Issue on MIMO
Systems and Applications, vol. 21, No. 3, pp. 374-381, April 2003.
[3] A. Stefanov and T. M. Duman, Performance Bounds for Space-Time Trellis Codes,
IEEE Transactions on Information Theory, vol. 49, No. 9, pp. 2134-2140, September 2003.
[4] H. El Gamal, A. R. Hammons Jr. and A. Stefanov, Space-Time Overlays for
Convolutionally Coded Systems," IEEE Transactions on Communications, vol. 51, No. 9,
pp. 1603-1612, September 2003.
[5] Z. Lin, E. Erkip and A. Stefanov, Exact Pairwise Error Probability for the MIMO Block
Fading Channel, Proceedings of IEEE International Symposium on Information Theory and
its Applications (ISITA), Parma, Italy, October 2004.
79
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.
Coded Cooperative
OFDM Systems
.
.
.
Information transfer through wireless local area networks (WLAN's) involves simultaneous
communication among multiple source--destination pairs. Wireless local area networks may
operate in infrastructure mode or as ad-hoc networks. In the infrastructure mode the
coordination of these multiple communications is done via the access point. The access point
processes all the signals transmitted from the sources (uplink) and forwards them to their
respective destinations (downlink). In the ad--hoc mode on the other hand there is no fixed
infrastructure and the terminals utilize other terminals as relays to transfer information from
the source to its destination. As the next generation of WLAN's will utilize Orthogonal
Frequency Division Multiplexing (OFDM), it is necessary to consider the analysis and
design of cooperative codes in the context of OFDM systems. We consider the analysis and
design of cooperative channel codes for single and multiple antenna OFDM systems. We
analyze the performance of the coded cooperative system by developing a framework for the
generalized block fading OFDM channel model and study the achievable diversity and
coding gains. We examine the performance for different cooperation scenarios and observe
significant gains over conventional non-cooperative OFDM systems.
Key-words: cooperative coding, fading channels, OFDM systems, wireless local area
networks (WLANS’s), multiple-input/multiple-output (MIMO) systems.
Participating Faculty: Andrej Stefanov (stefanov@poly.edu)
Website: http://eeweb1.poly.edu/stefanov/
[1] Jerry C. H. Lin and Andrej Stefanov, "Cooperative Coding for OFDM Systems,"
Proceedings of 9th Canadian Workshop on Information Theory, Montreal, Canada, June
2005.
[2] Liwen Yu and Andrej Stefanov, "Cooperative Space-Time Coding for MIMO OFDM
Systems," Proceedings of IEEE MILCOM, Atlantic City, New Jersey, October 2005.
[3] Jerry C. H. Lin and Andrej Stefanov, "Asymptotic Analysis of the Choice of Partners in
Coded Cooperative OFDM Systems," Proceedings of EUROCON, Belgrade, Serbia and
Montenegro, November 2005.
80
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.
Indoor localization
of WI-FI Tags
.
.
.
This project aims at developing a low cost device for locating items within buildings by
using Time Difference of Arrival (TDOA) Techniques. The TDOA estimation will be based
upon a WI-FI (802.11) signal emitted from the TAG. The main focuses of the research are:
1) Developing a low cost TAG that functions within the WI-FI network only to the degree
necessary to allow its localization based upon the emitted signal.
2) Developing signal processing methods that provide accurate TOA estimates at the access
points when operating in severe multipath environments.
Participating Faculty: Peter Voltz (voltz@rama.poly.edu), Henry Bertoni
(hbertoni@duke.poly.edu)
Collaborators: Binay Sugla, Mobile Matrix
[1] P. Voltz and D. Hernandez, Maximum Likelihood Time of Arrival Estimation for RealTime Physical Location Tracking of 802.11a/g Mobile Stations in Indoor Environments,
Proceedings of PLANS 2004 (Position Location and Navigation Symposium), April 26-29
2004, Monterey, CA.
81
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.
.
Capacity of.. MIMO systems with Antenna
.
Subset Selection
.
The capacity of multi-antenna (MIMO) systems has been heavily explored lately. Many
important results have been obtained, mainly for the very idealized channel with
independent, complex Gaussian gains. In this case it is known that the use of multiple
antennas on transmit and receive ends can increase capacity dramatically. In order to reduce
the hardware necessary for the Rf chains while still achieving large capacity gains, the idea
of antenna selection is to use multiple antennas at the transmitter and receiver, but to use a
smaller number of Rf chains and to “select” the best subset of the physical antennas to use
depending on the state of the channel. In this way much of the maximum possible capacity
gain can be retained, while reducing the hardware required. This project focuses on
improving the capacity of MIMO systems with antenna subset selection while operating
over more realistic channels than previously assumed (including fast fading, and non-ideal
channel estimation).
Participating Faculty: Peter Voltz (voltz@rama.poly.edu)
[1] Peter J. Voltz, Characterization of the Optimum Transmitter Correlation Matrix for
MIMO with Antenna Subset Selection, IEEE Transactions on Communications, November
2003.
82
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.
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.
.
IV.
VLSI, Electronics and Power
83
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.
.
.
Mitigation of.. Voltage Disturbances Caused by
.
Nonlinear Electrical
Massive Loads
.
Power utilities around the world become recently more and more concern about maintaining
high quality of power they provide for the customers. The reason for that is both increasing
number of nonlinear devices, which cause pollution of the voltage and sensitiveness of other
equipment to this pollution. Variation in the voltage level can be seen as annoying blinking
of fluorescent lights in our houses, but can also interrupt proper operation of modern
industrial machines or even damage some very sensitive appliance. Heavy and nonlinear
loads are main sources of the voltage distortion in the electrical power grids. In the example
below we can see a heavy induction motor powering a car shredder and causing variation of
the voltage on its terminal. This variation transmitted through utility lines may be the reason
for improper operation of the machine in the factory or can be seen in the house as a
fluctuating light.
V(t)
t
V(t)
House
Factory
t
V(t)
t
Participating Faculty: Zivan Zabar (zzabar@poly.edu) and Dariusz Czarkowski
(dcz@pl.poly.edu )
Collaborators: Tomasz Sulawa
Project is being conducted by the power group of the ECE department, Polytechnic
University.
Long Island Power Authority and KeySpan Energy sponsor this power research
project to investigate and mitigate disturbances in Long Island power network.
84
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.
.
. of a Unit Substation Demand
Development
.
Estimator ..
Today electric utility companies use a wide range of computerized applications for energy
management. These applications have an important role in many aspects in the power
system industry. Using real-time measurements and different data analysis methods, these
applications are responsible for the creation of reasonable and accurate representation of the
network. These applications are also used for short term and long term load forecasting
during significantly degraded operations.
A Unit Substation Demand Estimator (USDE) is needed to estimate missing data from
substations in various networks across NYC and Westchester County. As a starting point for
this study and the USDE development, Flatbush Brooklyn network has been chosen as the
first network to be tested.
This project describes the design and implementation of a USDE. The project presents
different methods for estimation of missing data measurements. Each method is tested in
detail to validate the accuracy of the estimated data and an estimation process strategy is
suggested.
By using the successive estimation methods and Visual Basic for Application code, a USDE
application is developed. The USDE application is then tested and special tuning functions
are developed to improve the estimation process and the estimation results.
j
Br
m i o ke n
ssi
ng link
da
ta
j
Bad data
??&&!!**
Bad data
??&&!!**
Typical power distribution network with broken communication links
Participating Faculty: Dariusz Czarkowski (dcz@pl.poly.edu ) and Zivan Zabar
(zzabar@poly.edu)
Collaborator: Yariv Ten-Ami
Sponsor: Consolidated Edison Company New York, NY
85
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.
.
.
High Speed Cryptographic
Architectures
.
. Message Authentication Codes (MACs) have been widely used in many
Encryption/Decryption and
. Socket Layer (SSL) and Transport Layer Security (TLS) use encryption
network applications. Secure
and authentication to support secure browsing, secure file transfer and secure remote login between
end users and servers. These high performance commercial servers and routers require dedicated
cryptographic hardware implementations to match the greater than 10 Gbps wire speed requirements
of network traffic. We are designing high speed architectures for encryption, authentication and
encryption with authentication cryptographic functions.
Encryption/Decryption
We designed architectures for symmetric encryption/decryption algorithm Advanced Encryption
Standard (AES) at 10Gbps or higher. Cryptographic cipher processing in software is incapable of
achieving 10 Gbps line rate. Hardware implementations of cryptographic algorithms DES, IDEA,
Twofish etc. have also been investigated. None of them yields a 10 Gbps throughput. We investigated
hardware architectures for high-speed Advanced Encryption Standard (AES) block and stream
ciphers that achieve 10 to 100 Gbps throughputs. The ten round 128-bit AES iterative block cipher
offers a variety of architectural options, each trading-off the circuit area/complexity with the
throughput. For example, a fully loop-unrolled architecture allows implementation of all rounds as a
single combinational logic block, reducing the hardware for round key multiplexing and the number
of clock cycles per block. However, this approach has a high area overhead and yields the worst
register-to-register delay.
A pipelined architecture increases the number of blocks of data being simultaneously processed. In a
full pipeline implementation where each stage implements one AES round, the system will output an
N-bit block at each clock cycle once the latency of the pipeline has been met. Here N is the
encryption/decryption block length. In this proposal, we extended this pipelined architecture further
by partitioning each AES round into two stages (sub-pipelining). This is based on an important
observation regarding in 128-bit AES data path, the 8-bit-in 8-bit-output SBox is the bottleneck. We
partitioned the round function into an Sbox stage and a stage that implements Shift Row, Mix
Column and Round Key XOR operations. Even though this second stage contains a multiplexer (to
bypass the Mix Column during the last round of encryption), the SBox operation still remains the
critical path. We implemented an optimized AES 10-stage pipeline architecture that implements 5
rounds with two pipeline stages per round. The first four rounds are optimized by removing the
bypass multiplexer in the second stage of the sub-pipeline since the Mix Column is always performed
in these stages. We store round keys in registers. This 10-stage pipeline architecture results in 2.1
cycles (2 + 1/10) per block. Our FPGA prototype of AES in the block cipher mode has demonstrated
that this architecture has the best trade-offs between performance and circuit area. A throughput of
more than 4.6 Gbps has been achieved for implementation.
Message Authentication Codes
We implemented 100Gbps hardware architectures for MACs based on universal hash functions. A
universal hash function is defined as follows: Let A and B be two sets and H be a family of functions
from A to B. H is a universal family of hash functions if for every pair x1, x2 ∈ A with x1≠x2, h∈ H
and h(x1), h(x2) ∈ B, the collision probability of h(x1) =h(x2) = 1/|B|. |B| is size of set B and 1/|B| is
the smallest possible value of the probability. We focus on Linear Congruential Hash (LCH), a
widely used universal function family. LCH is defined as:
k
hm, x (m)   (mi xi  t ) mod p
i 1
where mi is the ith word in a message block m and xi is the ith word in key x and t ∈ Zp. p is a prime
number which is typically close to 2w. Modular reduction of the accumulated result using p generates
either a w-bit or a w+1-bit hash value. The straightforward architecture of LCH as shown in Figure 1
(a) uses four 32-bit registers (R1, R2, H and L), two 64-bit registers (R3, r4), two 32-bit 2-to-1
multiplexers (mux1 and mux2), and two 64-bit 2-to-1 muxes (mux3 and mux4).
86
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We propose to divide a 2w-bit data path into two w-bit data paths and concatenate their results to
.
construct an equivalent 2w-bit data path. The concept of equivalence is crucial. Obviously, a
straightforward data path .and its corresponding divide-and-concatenate data path cannot be equivalent
. they output. We define two data paths to be equivalent if the results that
in terms of the results that
.
they output satisfy a pre-defined
property. For one way universal hash functions and associated
message authentication codes the actual result is not important. Rather, it is the collision probability of
the result that is important. Hence, we propose that two data paths implementing a hash function be
considered equivalent if they have the same collision probability. We defined equivalent data paths
and architectures for universal hash and associated MACs, when 1) they can process same size input
every clock cycle and 2) they have the same collision probability.
mulsrc
addsrc
mux1
mulsrc
s
xi
×w
R3
mux3
New block
16_bit
32_bit
1.4
H
loadr4 +2w
R4
R2
mux2
8_bit
1.6
p
R1
mi
addsub load
comp
Control signals
...
Hash
L
1.2
1
0.8
0.6
sign
ext
0.4
0.2
0
Control
mux4
1_stage
(a)
2-stage
3_stage
4_stage
(b)
 Figure 1: (a) A 32-bit architecture for LCH. The critical path is R1->X32->MUX3-> R3. (b)
Throughput/area ratios of equivalent divided-and-concatenate data paths with different pipeline stages.
Using the divide-and-concatenate technique a 32-bit LCH hash data path with a collision probability
of 2-32 can be constructed using two 16-bit LCH hash data paths, each with collision probability of 216
, and concatenating their 16-bit results to generate a 32-bit hash value. The equivalent 16-bit divideand-concatenate architecture consumes 11506 gates compared to 9071 gates by the straightforward
32-bit architecture. The 16-bit divide-and-concatenate architecture achieves 45% throughput
improvement with 26% area overhead. Applying divide-and-concatenate once more to construct each
16-bit LCH data path using four 8-bit LCH hash data paths yields an equivalent 32-bit LCH hash data
path from sixteen 8-bit LCH hash data paths. Compared to 32-bit straightforward LCH architecture,
this preliminary 8-bit equivalent divide-and-concatenate architecture achieves 101% throughput
improvement with 52% area overhead, which is shown in Figure 1 (b). We implemented either MMH
or TMMH or UMAC with a collision probability of 2-32 that is composed of sixteen 8-bit LCH hash
data paths. Based on the synthesis experiments, the throughput for the FPGA implementation is
>70Gbps.
Participating Faculty: Ramesh Karri (ramesh@india.poly.edu)
Website: http://cad.poly.edu/encryption/
Research supported by Cisco Systems
[1] B. Yang, R. Karri, D. A. Mcgrew, A High Speed Hardware Architecture for Universal Message
Authentication Code, submitted to IEEE Transactions on Computer.
[2] B. Yang, R. Karri, D. A. Mcgrew, Divide-and-concatenate: an architecture level optimization
technique for universal hash functions, IEEE/ACM Design Automation Conference (DAC), pp.614617, June, 2004.
[3] K. Alexander, R. Karri, I. Minkin, K. Wu, P. Mishra, and X. Li, Towards 10-100 Gbps
Cryptographic Architectures, Proceedings, International Symposium on Computer and Information
Science (ISCIS), Orlando, Florida, October 2002.
[4] B. Yang, R. Karri, D. A. Mcgrew, An 80Gbps FPGA Implementation of a Universal Hash
Function based Message Authentication Code, Third Place Winner, 2004 DAC/ISSCC Student
Design Contest, June 2004. http://www.dac.com/42nd/studcon.html.
87
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Secure Built-In-Self-Test
(BIST) Architecture
.
. implemented in hardware to meet high throughput requirements
Crypto algorithms are being
. crypto accelerators in System-On-Chip (SOC) devices for secure
and widely integrated as
applications ranging from tiny smart cards to high performance routers. In a secure SOC,
crypto coprocessors offload intensive arithmetic computations from the host processor. A
straightforward way to use BIST to test symmetric block cipher circuits is using an
additional Test Pattern Generator (TPG) and Output Response Analyzer (ORA) circuits. In
the test mode, the inputs to crypto data path are applied from the TPG instead of the
plaintext; the outputs from crypto data path are compressed into ORA as a signature.
In a BIST architecture, the aim of TPG is to provide random inputs to Circuit under Test
(CUT). Since exhaustive testing is almost impossible, for example AES data path needs 2128
test patterns, the probability distribution for test patterns determines the length of test
patterns to insure an acceptable level of fault coverage. LFSR tends to produce test patterns
having equal numbers of 0s and 1s on each output test pattern resulting in very long test
patterns for some circuits. Weighted random pattern generators bias the distribution of 0s
and 1s that makes test patterns more random thereby achieving a higher fault coverage with
fewer test patterns. Strong randomness is an inherent feature of crypto algorithms. A block
cipher can be considered as an instance of a random permutation over a message block under
the control of a key block. In fact, the security of a block cipher can be formalized by
pseudorandomness: if there is no way to distinguish the block cipher from an ideal random
permutation, then the block cipher can not be attacked. One or more round operations are
non-linear transformations in symmetric block ciphers. For example, in both DES and AES,
the non-linear substitution is used. The randomness of several symmetric block cipher
algorithms has been evaluated by National Institute of Standards and Technology (NIST).
In BIST technique, the ORA operates as a hash function; it compresses all the test results
into a signature. MISR is a simple hash function and widely used as ORA. Collision
probability is the most important parameter for a hash function. It is defined as the
probability that two different messages have the same hash result. The smaller the collision
probability is, the better the hash function. If a result sequence with faulty output vectors can
also be compressed into the correct signature, such faults can not be tested. Both the quality
of TPG and ORA determines the efficiency of the BIST technique. Block cipher in CBC
mode is the one of the most powerful hash function widely used in message authentication
code. It is computationally infeasible for such hash functions to find messages x and x’ such
that x’ ≠ x and hash (x’) = hash(x). A block cipher can be used either as a TPG with more
random output patterns or as an ORA with very low collision probability. Based on this key
observation, we develop a BIST technique called Secure BIST to test block cipher modules.
In the proposed Secure BIST technique, the output of a crypto core (ciphertext) is fed back to
the input of the crypto core (plaintext) in the test mode and the signature is compressed into
the output ciphertext register. The proposed Secure BIST technique incurs almost no area
overhead by using a crypto module itself as both the TPG and the ORA.
We validated Secure BIST on hardware implementations of Data Encryption Standard
(DES) and Advanced Encryption Standard (AES). The experimental results show that
Secure BIST is superior to LFSR-based BIST in terms of area overhead, fault coverage and
test sequence length.
Participating Faculty: Ramesh Karri (ramesh@india.poly.edu)
[1] Bo Yang and Ramesh Karri, A Secure Built-In Self Test Technique for Crypto Modules
in Secure Systems-On-Chip (SOC), submitted to IEEE Transactions on Computer.
88
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Fault Attack Resistant
High Speed
.
Crypto Architectures
.
.
Motivation: Because of the rapidly shrinking dimensions
in VLSI, transient and
permanent faults arise and will continue to occur in the near future in increasing
numbers. Faults can broadly be classified in to two categories: Transient faults that die
away after sometime and permanent faults that do not die away with time but remain
until they are repaired or the faulty component is replaced. The origin of these faults
could be due to the internal phenomena in the system such as threshold change, shorts,
opens etc. or due to external influences like electromagnetic radiation. The faults could
also be deliberately injected by attackers in order to extract sensitive information stored
in the system. These faults affect the memory as well as the combinational parts of a
circuit and can only be detected using Concurrent Error Detection (CED). This is
especially true for sensitive devices such as cryptographic chips. Hence, CED for
cryptographic chips is growing in importance. Since cryptographic chips are a consumer
product produced in large quantities, cheap solutions for concurrent checking are
needed. CED for cryptographic chips also has a great potential for detecting faultinjection attacks where faults are injected into a cryptographic chip to break the key.
Objectives:
• Investigate low-cost, low-latency CED schemes for Symmetric Block Ciphers
• Obtain close to 100% coverage without significant throughput degradation
• Develop CED techniques to resist all known and possible future attacks
Progress: We developed a fault resistant architecture for involoutional ciphers which
detects all possible faults in the datapath and consumes <20% area overhead, degrading
the throughput by <10% [1] [2]. We also extended this technique to be applicable to
Feistel Network Ciphers [4]. We developed a novel CED scheme for the Advanced
Encryption Standard (AES), which was chosen as the U.S Government (FIPS) standard
to be a royalty-free encryption algorithm for use worldwide and offer security of a
sufficient level to protect data for the next 20 to 30 years. This scheme makes use of
some of the invariance properties exhibited by AES [3]. These invariance properties of
AES are being used to investigate its weaknesses. In contrast, we use them to strengthen
the hardware implementations of AES and to protect it against fault attacks. The fault
injection based simulation of this scheme shows 100% fault coverage and the ASIC
implementations resulted in a very low area and throughput overhead.
Participating Faculty: Ramesh Karri (ramesh@india.poly.edu)
Website: http://cad.poly.edu/encryption
[1] N. Joshi, K. Wu and R. Karri, Concurrent Error Detection Schemes for involution ciphers,
Cryptographic Hardware and Embedded Systems (CHES) 2004, Springer Verlag LNCS vol.
3156, August 2004.
[2] N. Joshi, J. Sundararajan, K. Wu and R. Karri, CED schemes for involutional SPN networks,
IEEE Transactions on Computer Aided Design, under review.
[3] N. Joshi, S. Iyer, R. Karri, Invariance based CED for the Advanced Encryption Standard,
Submitted to IEEE Design Automation Conference (DAC) 2005
[4] N. Joshi, J. Sundararajan, K. Wu, R. Karri, Generalized involution based CED for Substitution
Permutation and Feistel Networks, IEEE Transactions on Computers, under review.
89
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.
. Nanoscale Systems
Fault Tolerant
.
.
New technologies based on nanoscale physical characteristics such as Resonant Tunneling
.
Diodes, Quantum-dot Cellular Automata and molecular electronics have been researched
and are being proposed as candidates for next generation device technologies. However,
physical limitations at the nanoscale result in highly unreliable fabrication mechanisms
which in turn translate into highly unreliable nano devices. Consequently, device failure rates
in these emerging nanotechnologies are projected to be in the order of 10-3-10-1.
Furthermore, the faulty behavior is time varying and hard to model. Overall, fault tolerance
is an important system level design objective in these emerging nanotechnologies. In current
CMOS based technologies, fault rates are static and in the range 10-9-10-7. The typical
techniques for addressing reliability in CMOS technologies, namely, extensive testing at
manufacturing time, and a limited amount of redundant hardware added into the circuitry for
high operation time reliability, cannot be successfully applied in emerging nanotechnologies
with much higher and time varying failure rates. Fundamentally, manufacturing processes
and hence failure mechanisms are different and the devices per unit area are several orders of
magnitude larger (~107 device/cm2 in CMOS vs ~1012 device/cm2 in emerging
nanotechnologies).
This research investigates design principles for building reliable systems from unreliable
nano device technologies of Quantum-dot Cellular Automata (QCA) and Negative
Differential Resistance (NDR).
Fault tolerant QCA building block design
Triple Modular Redundancy (TMR) is a straightforward way to provide fault tolerance
capability. However, TMR is not a good choice for designing fault tolerant QCA designs
since wires, faults in wires, and wire delays dominate in this nanotechnology. We propose
TMR using Shifted Operands (TMRSO) as a new approach to designing fault tolerant QCA
designs with lower area overhead and better performance than straightforward TMR 0. This
new method exploits the self-latching and adiabatic pipelining properties of QCA devices to
maximize throughput of a system since more than one calculation can be in the pipeline at a
given time. We have validated this concept on a two-bit adder as shown in Figure 1.
M2
Cout
D11
S0
D13
D12
M0
D8
S1
D6
M1
D10
D9
D7
D22
m0
D20
D19
FA0
m1
Cin
m2
FA1
D16
D15
D2
 Figure
D4
D3
D1
B
FA3
FA2
D18
D0
A
D25
D24
D17
D14
SEL
D21
D23
1A two-bit TMRSO adder
90
D5
.
.
.
.
.
Fault Tolerant NDR building
block design
.
Error checking code .based information redundancy approach has been regarded as a
powerful fault tolerance. scheme in communication and storage systems. Preliminary work in
. that, by exploiting the characteristics of certain Nanotechnology
this direction has shown
devices, linear block code based information redundancy approach can be applied to carry
save based arithmetic subsystems, thus providing a promising vision of further developing a
low-overhead unified fault tolerance scheme for Nanotechnology systems 0.
Figure 2 shows an example of fault tolerance carry save addition and the functional flow of
the fault detection technique in carry-save addition using linear block coding theory.
 Figure
3 Instruction issue process with
voter/C-unit structure
Fault tolerant nanotechnology processor design
We propose to investigate a new decentralized architecture that incorporates powerful and
flexible fault tolerance strategies in the Nanotechnology environment 0. As a preliminary
work, we have developed a fault tolerance strategy with a certain degree of decentralization in
computation units that dynamically selects between hardware and time redundancy in
response to the time varying fault rates in the system. Figure 3 shows a high-level view of the
instruction issue process and the interaction between the voters and the C-units.
Figure 2 Fault tolerance carry save addition
Participating Faculty: Karri Ramesh (ramesh@india.poly.edu)
Collaborators: Alex Orailoglu and Kaijie Wu
[1] T. Wei, K. Wu, R. Karri and A. Orailoglu, Fault Tolerant Quantum Cellular Array (QCA)
Design using Triple Modular Redundancy with Shifted Operands, ASP-DAC 2005, to appear
[2] W. Rao, A. Orailoglu and R. Karri, Fault Tolerant Arithmetic with Applications in
Nanotechnology based System, International Test Conference, pp. 472-478, October 2004
[3] W. Rao, A. Orailoglu and R. Karri, Fault Tolerant Nanoelectronic Processor Architectures,
ASP-DAC 2005, to appear.
91
Dept. of ECE - Grants and Contracts
Principal
Investigator(s)/
Co-PI(s)
Project Title
Agency
H. Bertoni (P. Voltz)
Location Technology for Indoors Wireless
Systems
Symbol
Technologies
F. Cassara
Ultra-Wideband OFDM Wireless
Communication Systems
Network Security
CATT
H. J. Chao (R. Karri)
Acquisition of Equipment for Research in
Cyber Security Processor Design
NSF
D. Czarkowski
High-Efficiency Wide-Bandwidth Dynamic
Supply Modulators for Linear RF Power
Amplifiers
NSF
E. Erkip
Multiple Transmit Elements for High Speed
Robust Wireless Local Area Networks
NSF
E. Erkip (Y. Wang)
Cooperative Source and Channel Coding
NSF
E. Erkip (A. Stefanov)
Cooperative Channel Coding for Wireless
Networks
Philips Research
D. Goodman (E. Erkip
and Y. Wang)
Power Efficient Multimedia Wireless
Communications
NSF/WICAT
H. J. Chao
CATT
D. Goodman (S. Panwar) Industry University Cooperative Research
Center for Wireless Internet
NSF
Z.P. Jiang
CAREER: Robust Nonlinear Control:
Problems and Challenges from
Communication Networks
Nonlinear Ship Control: An Opportunity for
Applied Mathematicians
NSF
U. S.-China Cooperative Research: Control
of Complex Nonlinear Systems with
Applications
NSF
NSF
Enhance Visual Target Detection Using
Air Force
Nonlinear Stochastic Resonance Technique
92
Principal
Investigator(s)/
Co-PI(s)
Project Title
Agency
R. Karri
Optical Speed Encryption Architectures
Cisco Systems
Towards Enabling a 2-3 Orders of
Magnitude Improvement in Call Handling
Capacities of Switches
NSF
Graduate Scholarship
Design
Automation
Conference
Control System Development for SelfNavigating Rotary Wing Aircrafts
IntelliTech
Microsystems
F. Khorrami
S.P. Kuo
Collaborative Research: Modeling and
NSF
Control of Fuel Cell Based Distributed
Energy System
Generation Characterization and Aerospace AFOSR
Applications of Torch Plasmas
Experiments in the Theoretical Study
ONR
ELF/VLF Wave Generation by the Haarp HF
Heating Facility
Y. Liu
I-Tai Lu
S. Panwar
Wave-Plasma Interactions in Artificial
Modification of the Ionosphere and
Magnetosphere by Haarp HF Heating
Facility
Network X-ities:--Foundations and
Applications
ONR
Wireless Communications
CATT
Sensor Management for EMI/EMC
Grumman
MIMO OFDM
Interdigital
Sensor Management/MIMO OFDM/RFID
CATT
Management, Performance and Control of
High-Speed Network
CATT
Polling-Based MAC for Wi-Fi Networks
C-Cation
ISIP
Panasonic
Digital
Cooperative Coding
Thomson
93
NSF
Principal
Investigator(s)/
Co-PI(s)
Project Title
Agency
Wireless LAN Analysis of Design;
Cooperative Medium Access Control
NSF/I/UCRC
Modeling and Design of Wireless PANs
Philips
Security eCAT
NYSTAR
NYSE Network Modeling
SIAC
Center for Advanced Technology in
Telecommunication
NYSTAR
S. Panwar (H.J. Chao)
High-performance Stable Packet Switches
NSF
S. Panwar (E. Erkip)
Co-operative Networks
NSF
S. Panwar (Y. Wang)
Support for Video Traffic in Ad-Hoc
Networks
NSF
K. Ross (S. Panwar and
Y. Wang)
P2P Video Streaming
NSF/CATT
I. Selesnick
Motion-based 3D Wavelet Transforms
ONR
A Motion-Selective 3D Wavelet Transforms
for Enhancement of Imagery in Video Data
ONR
I. Selesnick (Y. Wang)
Video Coding Using 3D Motion-Selective
Wavelet Transforms
NSF
P. Voltz
Indoor Localization in Multipath
Environments
Symbol
Technologies &
CATT
Y. Wang (I. Selesnick)
Wavelet-Based Video Coding
Mitsubishi
Electric
Research Lab
(MERL)
Z. Zabar
Development of a Unit Substation Demand
Estimator
Con Ed
Mitigation of Voltage Disturbance Caused By KeySpan
Non-linear Operation of Massive Electrical
Loads
94
Principal
Investigator(s)/
Co-PI(s)
Project Title
Agency
Z. Zabar (D. Czarkowski
and L. Birenbaum)
Evaluation of 3 –Φ Bolted Short Circuits on
Distribution Networks Having Customer’s
Distributed Generators
Con Ed
Availability of Monitoring/Warning Systems Con Ed
of Leakage Current to Ground in Secondary
Distribution Systems
Z. Zabar and L.
Birenbaum (D.
Czarkowski)
Phase-Angle as an Additional Indicator of
Imminent Voltage Collapse in Electric
Transmission and Distributed Systems
95
KeySpan
ECE Annual Research Report
Aims
The aim of the ECE annual research report is to report ongoing and current
research activities in the ECE Department of Polytechnic University. By “ongoing
and current” we refer to the research projects that have been undertaken by the
participating faculty within past three years.
Submission guidelines
When to submit
The Annual Research Report will be updated once a year. All contributors should
submit their new project description or any possible changes on their reports of
previous year by October 15 to Dr. Z. P. Jiang at zjiang@control.poly.edu.
Electronic submission is preferred.
What to submit
Each submitted project description should be less than or equal to two pages and
should contain enough details as suggested below:







Title of project
Description of project, including motivation, project objectives, preliminary
results (if any), and potential impact of your research. Colorful figures and tables
are welcome.
Key-words (not exceeding five)
Names and email addresses of participating faculty, and if applicable a short list
of your collaborators. Mark the name of contact person for the project in
question.
Funding resources of the project in the last three years, if applicable.
References: providing the reader with a short list of selected publications on
your preliminary work. If possible, create a website for the link to any further
details and progress on your ongoing project.
Please submit a WORD file with single column and 12 point font.
Copyright
Submission of a research write-up implies that the technical contents in any form
are original and that the participating faculty members of each report are
responsible for accuracy of the information provided therein.
96