KOCSEA Symposium 2009
Trends of Communications
Technologies
Myung Jong Lee
Dept. of Electrical Engineering
Cilee@ccny.cuny.edu
Outline
 Evolution of Communications Technologies
 Recent Entropy Boosters
 Industry activities: cases in IEEE 802.15
2
NBT?
 Extrapolation
 Past historical samples
 Energy conservation law: 1st law of
thermodynamics
 Law of entropy: 2nd law of thermodynamics
3
Entropy as a measure (1)
 Entropy
In thermodynamics:
• Definition: S=q/T (joules/degree)
– Tendency of spontaneous energy becoming
diffused and spread out
• Natural progress or phenomena in the
direction of increased entropy
– Wind blows, ice melts, mountain lowers and
valley rises,
– Berlin wall torn down, equal rights for women,
etc
4
Entropy as a measure (2)
 In a dictionary
• Degree of freedom or degree of randomness or chaos,
degradation
 In Information Theory:
H   pi log(1/ pi )
i
• Pi: the probability of event I
• Maximum Entropy when Pi ‘s are equal.  Uniform
distribution
– (socio-political views) elite group (monarchy)
democracy (all people)
– Possession of information: “知彼知己 百戰百勝”
• Internet, ubiquitous networks: information age!
5
Entropy as a measure (3)
 In short, Leveling Force is the core of the entropy
law!
 Democratization, equal right’s movement, empowering
individuals, fostering egalitarian society even for animal,
plants, and environment (utopia?) etc.
6
Entropy Drivers
 Decentralization, distribution
 Flexibility, future proof
 Personalization, user-centric
 Horizontal market
Blurred distinction between computer and
communications
 Cross cutting disciplines
 Etc, etc.
7
Quntum Jumps in Entropy
In Communications
1.
2.
3.
4.
5.
Centralized system to distributed system
Circuit Switching to Packet Switching
Wired to Wireless
Infrastructure to Infrastructureless
Toward Ubiquitous Networks
Recent Entropy boosters
8
1. Centralized to distributed
 Single large computer: single terminal to remote
multiterminal
 Multiple mini computers
 Many personal computers
 Ubiquitous computing or networking
• Provide computing resources wherever demands exist.
• Grid computing, nano computing, biocomputing, etc
 This evolution demands efficient communication
and management
9
2. Circuit to Packet
 Circuit switching serves well for voice service for
over 100 years
 Dedicated services to shared services
 Again, demands for flexibility, multimedia (voice,
video, data), personalization lead to packet
switching Packet switched Internet -> VOIP
 No technology without problems!
 Problems are mainly due to increased degree of
randomness
 Diverse QoS’s for multimedia, Congestion, etc
10
3. Wired to Wireless
 People as well as machine long to be untethered
 Evolution of wireless communications
1st generation: analog
• AMPS
2nd generation: digital (voice+data)
• IS-95, GSM, CDPD for data
3rd generation: digital (voice+data+low rate
video)
• IMT-2000 (3GPP, 3GPP2), Cdma 2000, GSM (wider
bandwidth)
• WBMA (IEEE 802.16, 20), WLAN (IEEE802.11), WPAN (IEEE
802.15, ZigBee), WBAN (IEEE 802.15 IG)
4th generation: Network convergence
• multimedia (HDTV), IMT-Advanced (ITU-R)
• Unifying PHY, MAC with SDR?
11
4. Infrastructure to infrastructureless
 Wireless Communication infrastructure
 Base station or Access point based
•
•
•
•
•
WWAN “last mile” wireless
WLAN (WiFi) “last 100m” wireless
WPAN  “last 10m” wireless
WBAN  “last 2m” wireless
Or, Macrocell, Microcell, Nanocell, Femtocell
 Infrastructureless or Wireless Ad hoc networks
 Peer-to-peer mesh communications without BS or AP
• No “last x” wireless
• Mobile Ad hoc networks (MANET), Wireless Mesh networks,
WSN, WBAN
13
Ad Hoc Networks
 Infrastructureless
 Wireless nodes possibly with mobility
 Possibly multiple hops between network
nodes
Router or relay node as well as end-node
Multihop occurs as data rate gets higher.
• IEEE 802.11b (100m)802.11a (<<100m)
• IEEE 802.15.3c (mmwave)  Multihp,
antenna
• IEEE 802.11ac, ad
directional
14
Applications for ad hoc networks
 Emergency networks
 Search-and-rescue, firefighting, policing
 Civilian environments
 Gaming, meeting room, stadium
 WPAN, WBAN
 Cell phone, PDA, earphone, wrist watch





Vehicle to Vehicle networks
Military
Wireless mesh networks
Wireless Sensor networks
Etc
15
5. Ubiquitous Networking
 Key capability to
maximally
satisfy personalized
requirements-
user-centric
 “awareness” technology
 Device-to-Device
communications
 At the center of U
Network lies the wireless
sensor/control networks
16
Wireless Sensor Networks
 80’s Microprocessor
 90’s Internet
 This decade—”Sensors”
 Gary Boone of the Accenture Technologies
Laboratory asserted that "browsing reality" will
prove to be the killer application for wireless
sensor networks,
Courtesy: David Nagel
17
Wireless Sensor Networks
 Multihop ad hoc networks, but relatively
static
 Resource constraints: energy, processing,
memory
 Potentially numerous (inexpensive)
 Wireless channels: intermittent and
bandwidth-limited
 Miniaturization
18
WIRELESS SENSOR NETWORKS
Courtesy: David Nagel
19
Applications
 Automation and control:
 home
 Factory, warehouse
 Energy saving (NYC apartment complex project)
 Monitoring
 Safety, security
 Health (BAN)
 Environments (agriculture, building, aqueous, etc)
 Situational awareness and precision asset location (PAL)




military actions
Ssearch and rescue (breadcrumb comm, use of mice?)
autonomous manifesting
Inventory tracking
 Entertainment
 learning games
 interactive toys
20
What a home!
Courtesy: Zigbee
Some Research Issues
 Key is to integrate communication, processing, and
sensors in a miniaturized platform to provide
ubiquitous sensing and control environment.
 General
 Energy, Energy harvesting
 Crosslayer Optimization (QoS, scalability, reliability,
efficiency)
 Self Organization, Self healing
 Connection to widearea networks: Gateway (conversion
or convergence)—IEEE 802.15.5, IETF 6lowpan, ROLL
 Security
 data fusion, mining
 Miniaturization (antenna, etc)
22
Research Issues (2)
 At Protocol Layers
 PHY (adaptive modulation, voltage scaling, antenna, CR)
 Energy Efficient MAC (synchronous, asynchronous,
asymmetry approach, wakeup radio, multichannel/CR
MAC, Virtual MIMO, cooperation)
 Link control (hybrid of ARQ/FEC, power control)
 Network (addressing, routing (unicast, multicast,
broadcast, geocast), beacon scheduling, topology
control, frequency agility, CR, cooperation, network
coding)
 Transport (wireless multihop)
 Applications (data fusion, unifying data format IEEE1451)
23
Energy Saving Example
24
Energy Saving for WSN
 For IEEE 802.15.5 WPAN Mesh
 Power saving algorithms are needed for IEEE
802.15.5 WPAN Mesh for wireless
sensor/control networks
 Using IEEE 802.15.4 device
 One of the advantage of using IEEE 802.15.5
mesh for WSN (sleeping router)
An Overview of IEEE 802.15.4 (1)
 Bandwidth and data rate
868/915 MHz PHY
2 MHz
Channel:
0
Frequency: 868 MHz
Data rate:
20 Kb/s
1
2.4 GHz PHY
5 MHz
......
10
902 – 928 MHz
40 Kb/s
11
......
2.4 – 2.4835 GHz
250 Kb/s
26
An Overview of IEEE 802.15.4 (2)
 Beacon Mode and Superframe Structure
Beacon
Beacon
GTS
GTS
Inactive
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
CAP
CFP
SD = aBaseSuperframeDuration x 2SO symbols
(Active)
BI = aBaseSuperframeDuration x 2BO symbols
Design Consideration
 Mesh layer solution based on IEEE 802.15.4-2006
 Supporting long battery life
Two AA batteries, 1year
 Flexible active time
 End-to-end latency constraint
 Considering receiver energy consumption
Tree relation
 Easy implementation
Battery Life
 Two AA batteries
2000 mA-hr
 Energy consumption of cc2420
Tx; 17.4 mA
Rx; 19.7 mA
 When a device turns on the transceiver
4.2 days
 When the device keeps 5% active time
84 days (under 3 months)
 Minimizing active ratio is the key!
Mesh Layer Solution
 Why Algorithms at Mesh Layer?
MAC access limited in many transceivers,
-MAC information not accessible
-Cannot add MAC control frames
-Only access via standard primitives
At mesh layer,
flexible and platform independent
 Timing problem
Can not guarantee response time
Ex. The time from calling MCPS-DATA.request to starting backoff
Representative Algorithms
 6 Generic Power Saving Algorithms
applicable to a wide range of MAC
protocols
With beacon mode
Determining parameters: Beacon interval and superframe
duration
-Non-beacon Tracking (NBT)
-Beacon Tracking (BT)
With non-beacon mode
Determining parameters: Wakeup interval and wakeup
duration
-Long Preamble Emulation (LPE); BMAC
-Long Preamble Emulation with Ack (LPEA); XMAC
-Non-beacon Tracking Emulation (NTE)
-Global Synchronization (GS); SMAC
Algorithms with Beacon Mode
 Reliability, Beacon collision
 Upper layer control also required
Synchronous Algorithm with Non-Beacon
 SMAC
 Time control precision
 Difficult to synchronize all devices
Asynchronous with Non-beacon Mode
 LPE
 LPEA
Average active ratio with the beacon mode
10
Anal:NBT
Anal:BT
Exp:NBT
Exp:BT
9
8
Active ratio (%)
7
Three
Transmitters
6
5
and
one receiver
4
3
2
1
0
0
0.5
1
1.5
2
2.5
Wakeup intervals (s)
3
3.5
4
Average active ratios with the non-beacon mode
10
Anal:LPE
Anal:LPEA
Anal:LPEAS
Anal:GS
Exp:LPE
Exp:LPEA
Exp:LPEAS
9
8
Active ratio (%)
7
6
5
4
3
2
1
0
0
0.5
1
1.5
2
2.5
Wakeup intervals (s)
3
3.5
4
Hop latencies of the algorithms
25
Anal:NBT, BT
Anal:LPE
Anal:LPEA, LPEAS
Anal:GS
Exp:BT
Exp:LPE
Exp:LPEA
Exp:LPEAS
6 hop Latency (s)
20
15
10
5
0
0
0.5
1
1.5
2
2.5
Wakeup intervals (s)
3
3.5
4
Beacon vs. Non-beacon Mode
 Beacon mode
Suitable for the networks with
Long beacon interval & small number of neighbors
Hard time beacon transmission  beacon collision
Unreliable
NBT; beacon collision
BT; Sync tree problem
Upper layer support for
Active time scheduling, minimizing active time, broadcasting frames
 Non-beacon mode
Requires all operations at the mesh layer
Difficulty in timing control
Flexible !, can make better solutions for large scale
networks
For Large WSN Environment with LPEA
 The Key to control the energy consumption is the
wakeup interval
 Global Optimization with Unicast and broadcast
 Minimize Energy consumption vs Maximizing Network life
time with wake-up interval
Homogeneous WI
 Non-homogeneous WI
 Heuristics
For Network Environment with LPEA
50 Node
Network
For Network Environment with LPEA
Optimization Problem for unicast
Minimize energy
consumption
Maximize Network
Lifetime
Active Ratio
43
Performance Comparison
44
Performance Comparison
45
Quntum Jumps in Entropy
In Communications
1.
2.
3.
4.
5.
Centralized system to distributed system
Circuit Switching to Packet Switching
Wired to Wireless
Infrastructure to Infrastructureless
Toward Ubiquitous Networks
Recent Entropy boosters
46
Recent Entropy Boosters
 Dynamic Spectrum Technology-leveling disparity in
spectrum use
 Leveling disparity
 Cognitive Radio
 MIMO
 Leveling the spatial & frequency disparity
• Array gain, SNR gain, enhanced data rate, etc
 Cooperative Communications (virtual MIMO)
 Leveling spatial and frequency disparity
 WBAN
 Personalization, decentralization, leveling spatial and
frequency disparity
 FiWi
 lowering the wall between Fiber and Wireless
 Ex: RoF (Radio over Fiber)
47
Bandwidth—name of the game
 Avenues
Bandwidth and power efficiency (Bits/Hz/Joule)-64QAM and Turbo coding get near Shannon limit. –fill
the hole in bandwidth
Dynamic spectrum; spectrum sharing…fill the gap
New spectrum: very costly, therefore, exploring tera
hertz band (electronics limitation) –IEEE 802.15
Interest group for THz. –dispersion to unexplored
territory
Spatial reuse: cellular concept. (lowering transmit
power –boosting channel/hz
48
Dynamic Spectrum
FCC 2004 Policy change
 New spectrum policy to mitigate the scarcity of
spectrum resource
 Unlicensed operation for TV bands (white space)
 Ch. 5-13, Ch.21-51 (except ch.37) (76-698 Mhz)
 Ch. 14-21 in rural area
 Opportunistic Spectrum Sharing : Space and Time
 Primary (vertical) sharing—finding and using white space
 Secondary (horizontal) sharing –dissimilar networks then
sharing spectrum efficiently
 Industrial Standards Development
 IEEE 802.22 (Wireless Regional Area Network: WRAN)
 IEEE 802.18 (Coexistence)
 IEEE P1900
 ECMA
49
Spectrum Usage NYC Sept 1, 2004
16% duty cycle, 30Mhz-3 Ghz, 24Hrs
 Actually even lower ( <10%)
copyright kiran.challapali@philips.com
50
Cognitive Radio

To protect licensed service operator

Essential component of SDR

To aware of spectrum usage in vicinity

Time and space

Cooperative sensing, etc

Intelligent decision on sensing results.

Current research focus:

Fast and accurate spectrum sensing (energy & feature)

Spectrum management

Radio technologies
from IEEE 802.22-040003r0
51
Inerference Avoidance
Copyright: pkolodzy@stevens-tech.edu
52
IEEE 802.22 WRAN
 Scope
 To specify the air interface (PHY and MAC)
 Fixed point-to-multipoint wireless regional area networks
operating in the VHF/UHF TV broadcast bands between
500MHz and 862 MHz.
 Purpose
 Alternatives to wireline broadband access to diverse
geographic areas (rural areas, etc),
 Use of TV bands.
53
IEEE 802.22
from IEEE 802.22-040003r0
54
Cooperative communication
 Node close together can cooperate each other:
 cooperatively receive, form a multiple-antenna receiver
 cooperatively transmit, form a multiple-antenna transmitter
 Virtual MIMO
 It may not be practical for sensor networks to adopt the real MI
MO (size, power), but cooperation between sensor nodes can
achieve a virtual MIMO.
55
Basic Relay Model
Relay
Source
Dest.
 Two general approaches for Relay
 Decode-Forward
 Amplify-Forward
 Relay scenario:
 Rayleigh fading channels + AWGN noise
 Half-Duplex constraint
 Channel State Information (CSI)
56
Issues
 Gains vs. Overhead
 How much gains from cooperation?
 Will the gain outweigh overhead incurred by it?
 Cooperative partner selection, CSI information sharing
 Cooperative coding design (space-time coding)
 Power control
 Real network environment
 Will cooperation cause more collisions in real large
networks?
 How often will cooperation happen in a practical network?
 Performance gain at the relay node at the price of its ow
n throughput ?
 Will cooperation improve performance of overall network
s?
57
WBAN
 Natural extension
 WRAN WMAN  WLAN  WPAN  WBAN
 Nominal range of 2 m
 New regulatory body: FDA in addition to FCC
 Recently Standard activity IEEE 802.15.6
 Wearable and Implanted
 Single PHY or Multiple PHY
 Frequency BANDs
• ISM Band: 868/915MHz, 2.4GHz, 5.8GHz
• UWB band: 150-650MHz, Low band (3.24-4.74GHz), High band
(5.94-10.23GHz)
• Medical bands
– MICS (medical implant communication service) (402-405MHz)
– WMTS (wireless medical telemetry service) (608-614 MHz, 13951400MHz and 1427-1429.5MHz)
– MEDS (medical data service) (401-402MHz and 405-406MHz)
– New Band?
• Intrabody
58
Body Area Networks
 Usage Scenarios
Body senor network
Fitness monitoring
Wearable audio/video
Mobile device centric
Remote control &
I/O devices
Courtesy: Stefan Drude, Philips
July
2006
Body Sensor Network
 Medical application
Vital patient data
Wireless sensors
Link with bedside monitor
Count on 10 – 20 sensors
 Five similar networks in range
 Minimum setup interaction
 Potentially wide application
 Total traffic / patient < 10 kbps
Courtesy: Stefan Drude, Philips
July
2006
Medical and Entertainment
www.newscientists.com
61
Gastrointestinal Camera
www.givenimaging.com
5
201603-24
IEEE 802.15.6 Technical Issues
 Operates on, inside, or in the vicinity of the body.
 Limited range (< .01 – 2 meters)
 The channel model will include human body effects. (absorption, health ef
fects)
 Extremely low consumption power (.1 to 1 mW) for each device
 Capable of energy scavenging / battery-less operation
 Support scalable Data Rate: 0.01 – 1,000 kbps (opt 10Mbps)
 Support different classes of QoS for high reliability, asymmetric traffic,
power constrained.
 Needs optimized, low complexity MAC and Networking layer
 High number of simultaneously operating piconets required.
 Application specific, security/privacy required.
 Small form factor for the whole radio, antenna, power supply system
 Locating radios (” find me”) mode.
63
64
IEEE 802.15 (WPAN)
 Wireless Personal Area Networks (WPAN) with nominal range of
10-30m
 Branched from IEEE 802.11 WG 10 years ago
 Completed:
 802.15.1: Bluetooth v.1.0: 1Mbps
 802.15.2: Coexistence between 802.11
 802.15.3a: Very high rate UWB PHY for commercial applications
(disbanded)
 802.15.3b: MAC for high rate applications
 802.15.3c: PHY 500Mbps for commercial applications at 60GHz
 802.15.4, 4b: low power, low rate (256Kbps)--lower two layers for
ZigBee
 802.15.4a: UWB for ranging and midrate upto 25 Mbps
 802.15.5: WPAN Mesh based on 15.4b—2.5 layer approach
 802.15.c, 15.d: 15.4 PHY for China and Japan
65
IEEE 802.15 (WPAN)
 On going
802.15.4e: MAC enhancement for inudustrial applications
 802.15.4g: SUN for smart grid
802.15.6: WBAN
802.15.7: Visual Light Communications
802.15.4f: RFID
 Interest Group: Terahertz group
More details at IEEE 802.15 WG home page!
66
In summary,
Entropy Law may be able to explain and predict,
in perspective, the IT technology trend !
67
Advanced Wireless Research Lab (CUNY)
Standard
Activities
Basic
Research
Testbed &
Prototype
68
Slide 69
Myung. J. Lee CUNY