CWINS
IIT Colloquium: NRC
Ottawa, Canada
A Vision for Evolving Local Wideband
Wireless Networks
Kaveh Pahlavan,
Professor of Electrical and Computer Engineering and
Director, CWINS/WLRL
WPI, Worcester, MA
http://www.cwins.wpi.edu
Outline
•
•
•
•
•
Applications and the market
Existing technologies and limitations
Evolving standards
Overview of Global activities
Some research projects
Classification of Existing Wireless Networks
Voice Driven Networks
•
Low power, high quality, local services (PCS, wireless PBX, telepoint)-Result
of success in cordless telephone industry
•
High power, low quality, wide area (Digital Cellular) -Result of demand for
higher capacity for mobile radio
Data Driven Networks
•
High speed local (Wireless LAN) - A new approach for local area networking
•
Low speed wide area (mobile data) - Result of success in paging industry
Current Wireless Network Industry
Data Services
Voice Services
No. Users
Mobility
Tariff
Interoperability
Mobile
Data
WLANS
Mobility
Cellular
CWINS@wpi
Size/Power
PCS
Quality
Data Rate
Service Area
Intelligent
Network
Service Area
CWINS@wpi
Size/Power
Wireless LANs
•
•
•
•
Minimum data rate: 1Mbps (IEEE 802)
Designed for local indoor - less than 100m
Should interoperate with wired LANs
Does not need large investment on infrastructure and does
not collect service charges.
• Transmission technology: spread spectrum, standard
radio, IR
• Examples: Roamabout, WAVELan, Photolink, FreePort
• Standards: IEEE 802.11, HIPERLAN
History of Wireless LANs
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•
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•
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•
•
•
•
•
Diffused Infrared - 1979 (IBM Rueschlikon Labs - Switzerland)
Spread Spectrum using SAW Devices - 1980 (HP Labs - California)
Wireless modems - early 1980's (Data Radio)
ISM bands for commercial spread spectrum applications - 1985
IEEE 802.11 for Wireless LAN standards - 1990
Announcement of wireless LAN products - 1990
Formation of WINForum - 1992
ETSI and HIPERLAN in Europe - 1992
Release of 2.4, 5.2 and 17.1-17.3GHz bands in EC - 1993
PCS licensed and unlicensed bands for PCS - 1993
1996: .........
Three Views of WWLA
• Existing WLAN Applications
• Vision for Military Applications
• Vision of the Service Providers
Service Scenarios
• Workplace - the main market of today,
TCP/IP applications, legacy LAN backbone
• Home - universal access point: Internet
connection, cordless telephone, flexible
speakers, etc. backbone unknown (ATM
preferred).
• Nomadic public access - backbone
unknown, easier traffic policing and
charging with WATM.
Wireless LAN Technologies
Technique
DF/IR
DB/IR
RF
DS/SS
FH/SS
Data Rate
1 - 4 Mbps
10 - 155 Mbps
5 - 10 Mbps
2 - 20 Mbps
1 - 3 Mbps
Mobility
Stationary/Mobile
Stationary w/LOS
Stationary/Mobile
Stationary/Mobile
Mobile
Range
50 - 200 ft
100 ft
40 - 130 ft
100 - 800 ft
100 - 300 ft
Freq./wavelength
800 - 900 nm
800 - 900 nm
18 GHz, ISM
ISM bands
ISM bands
Modulation
OOK
OOK
FSK/QPSK
QPSK
GFSK
Access Method
CSMA
CSMA
Res. ALOHA, CSMA
CSMA
CSMA
Manufacturer
Spectrix
InfraLAN (token ring)
JOLT (pt-to-pt)
Motorola - Altair
DEC
AiroNet
WaveLAN (mesh)
Persoft
Solectek
Proxim
Windata
WiLAN
Proxim
RDC
Xircom
Wireless LAN Market
1200
1000
800
K-Unit
600
400
200
0
1992 1993 1994 1995 1996
Local Wideband Wireless Activities
• Evolving Standard Technologies
– IEEE 802.11
– RES-10 HIPERLAN
– Wireless ATM Forum
• International Activities
– In the US
• WINForum, U-NII
– In the EC
• MEDIAN, WAND, SAMBA and AWACS
– In Japan
• MMAC (High-Speed WirelessAccess and Ultra High-Speed Radio
LAN)
Interconnection between WLAN/WATM to backbone
Fixed Terminal
Server
Mobile Terminal
Backbone Network
Access Point
Applications
Applications
TCP
TCP
IP
IP
802.11 MAC
802.11 MAC
802.3 MAC
802.3 MAC
802.11 PHY
802.11 PHY
802.3 PHY
802.3 PHY
(a)
Applications
Applications
TCP
TCP
IP
LANE
IP
802.11 MAC
802.11
MAC
AAL5
AAL
ATM
ATM
802.11 PHY
802.11 PHY
PHY
PHY
(b)
Applications
Applications
TCP
TCP
IP
IP
AAL
AAL
WATM
WATM
Custom PHY
Custom PHY
(c)
ATM
ATM
PHY
PHY
802.11 Configurations
Infrastructure Network
ESS
BSS 1
AP
Existing Wired LAN
AP
BSS 2
Ad Hoc Networks
AP
BSS 3
BSS 2
BSS 1
IEEE 802.11 and ISM bands
• Media Access Protocol (MAC) for both peer-to-peer and centralized
topologies
• Uses 2.4 MHz ISM bands
• Supports DSSS (BPSK and QPSK), FHSS (GFSK), and DFIR (OOK)
• Data rates are 1 and 2 Mbps for DSSS and FHSS, 1Mbpsfor DFIR
• For DSSS the band is divided in two groups:
Group I centralized at: 2412, 2442, and 2472 MHz
Group II centralized at: 2427, and 2457 MHz
• For FHSS three patterns of 22 hops out of 79 available I MHz bands with
GFSK. Minimum hop rate is 2,5 hops/second
• Provide interoperatability among all stations
IAPP
(Supported byLucent, Aironet, Digital Ocean)
• The IAPP specification defines how access points from different
vendors communicate with each other to support mobile stations
roaming across cells and how they communicate across the backbone
network to hand over mobile stations.
• The IAPP specification builds on the baseline capabilities of the IEEE
802.11 standard.
• The IAPP specification tackles higher-level OSI layers such as logical
link control that facilitates inter-access point communications.
• The IAPP specification supports interoperability between products.
• Should be applicable to large infra-structures
Hiperlan ad-hoc network configuration
RIB {RDest , RNext , RDist }
NIB {NNbour , NStatus }
HIPERLAN 1 RIB
HIB {HDest , HStatus , HNext }
RIB
NIB
HIB
AIB
AIB {AOri , AAlias }
SMRIB {SSMR , SSeq }
F
TIB {TDest , TLast , TSeq }
is S
MR
NIB
HIB
AIB
SMRIB
TIB
2
1
of
is S
MR
of
3
5
F
of
Neighborhood
RIB
NIB
HIB
AIB
SMRIB
TIB
is S
MR
RIB
NIB
HIB
AIB
4
HIPERLAN 2
RIB
NIB
HIB
AIB
SMRIB
TIB
6
F
RIB
NIB
HIB
AIB
ETSI Res-10: HIPERLAN
• MAC for both peer-to-peer and centralized
networks
• Uses 5.25-5.3 GHz and 17.1-17.3 GHz
• Uses GMSK modulation with DFE
• Data rates are 10-20 Mbps
• The maximum range is 50m
• Supports asynchronous data as well as
isochronous voice
Wireless ATM Architecture [WATM
Working Group Presentation]
Comparison of WLAN and WATM
W
I
R
E
802.11
L
E
S
S
Frequency Band
Modulation
Technique
S pread S pectrum
Direct S equence:
2.4-2.4835 GHz,
Frequency
Hopping: 2.42.4835 GHz;
Diffused Infrared:
850-950 nanometer
S pread S pectrum
1 and 2
Direct S equence:
M bps
DBPSK, DQPSK;
S pread S pectrum
Frequency Hopping:
2GFSK, 4GFSK
BT=0.5; Diffused
Infrared: 16 and 4 PPM
5.15-5.30 GHz
Low bit rate: FSK;
High bit rate:GM SK
(BT=0.3)
L
A HIPERLAN
N
W
I
R
E MII
L Bahama
E
S
S
Access Method
Topologies MAC Services QoS
Basic CSM A/CA,
Ad-hoc,
RTS/CTS, PCF with Infrapolling list, 20
structure
frames
1.47 and
Non-Preemptive
23.53 M bps M ultiple Access
(NPM A), 10 PDU
900 M HZ
OFDM or GM SK with 2-20 M bps
(Proposed 5 GHz U- LM S or RLS
between
NII Bands)
Equalization
laptop and
PBS, and
Gbps
between
PBSs
Ad-hoc
Availibility
Authentication,
Encryption,
Power
conservation,
Time bounded
services
No explicit support
for QoS, but includes
infrastructure
topology and priority
scheme in PCF that are
useful for quality
assurance.
Technial standard finalized.
Final administrative approval
under progress. Products (e.g
DEC Roamabout) and
chipsets (e.g. Harris PRISM
and Raytheon RAYLINK) are
available.
Encryption,
Power
conservation,
Routing and
forwarding,
Time bounded
services
Advanced user
priority scheme and
packet lifetime
mechanism to support
QoS
Standard is finalized. No
product in the market. Two
prototypes: HIPERION, fully
standards compliant, and
LAURA, not fully compliant
[Wil96].
Prototype at Bell labs in
Lucent Technologies
Distributed Queue
Reservation Updated
M ultiple Access
(DQRUM A):
Reservation and
Piggybacking
Infrastructur Scheduling,
e, ad hoc
piggybacking
base station etc.
placement
(optional)
Base station
responsible for
checking and
guaranteeing QoS,
connections with or
without QoS
guarantees possible.
Infrastructur Scheduling,
e based
multiplexing and
demultiplexing
of VCs
ABR, UBR, VBR and Prototype at NEC USA's
CBR slots are available C&C Research Laboratories,
but QoS support is
Princeton, NJ.
not finalized
2.4 GHz ISM
Bands
/4 - QPSK with
decision feedback
equalization
8 M bps
TDM A/TDD with
Slotted ALOHA
5.2 GHz
16 Channel OFDM
> 24 M bps
Reservation, Slotted Infrastructur Scheduling, radio
ALOHA: M obile
e Based
resource
Access Scheme based
management and
on Contention and
under further
Reservation
study
(M ASCARA)
NEC
A
Magic
T
WAND
M
Data Rate
Worst case QoS
Prototyping under the
estimate (cell delay or European ACTS AC085
cell loss) to be used for project
determining the
connection
Wireless ATM Activities
WATM System
Frequency Bands
SWAN1
2.4 GHz ISM Bands
Data Rate
Modulation Scheme
625 kbps
Frequency Hopping
Medium Access
Each mobile has a
fixed channel; token
passing
Packet
Format/Addressing
Handoffs/roaming
Various types of
link cells
Mobile initiated
MII/BAHAMA1
900 MHz (Proposed
5 GHz : U-NII)
2-20 Mbps
(suggested OFDM
or GMSK with
LMS/RLS)
Distributed queue
reservation updated
multiple access
(DQRUMA)
Custom wireless
and LANE
Mobile initiated
Olivetti
2.4 GHz ISM Bands
NEC
2.4 GHz ISM Bands
WAND
5.2 GHz
10 Mbps
QPSK
8 Mbps
/4 - QPSK with
DFE
24 Mbps
16 channel OFDM
Reservation with
Slotted Aloha and
piggy-backing on
data cells
see [POR94]
TDMA/TDD with
Slotted Aloha
Reservation with
Slotted Aloha
see [RAY97]
LANE
Mobile initiated
Mobile initiated
Mobile initiated
16 bit CRC and
ARQ
Data Link Control
for error recovery
FEC
Priority for certain
traffic
[POR96],[POR94]
Fixed slots available
for QoS support
[RAY97]
Worst case QoS
estimate to be used
[WAND96]
(with Mobile Manager)
Infrastructure
initiated (with Mobile
Representative)
Techniques for
reliability
FEC with (8,4)
linear codes
QoS
MAC supports QoS
FEC (proposed
Reed-Solomon
Codes for real-time
traffic and
FEC/retransmissios
for data
Supported
References
[AGR96]
[ENG95],[AYA96]
Table 3.3.1: Wireless ATM Activities
1
Lucent Bell Labs
European Wideband Wireless Activities
Table 4.3.1: European Wireless Wideband Activities
Project
MEDIAN
WAND
SAMBA
AWACS
Full Name and
Number
AC006
Wireless Broadband
CPN/LAN for
Professional and
Residential
Multimedia Services
AC085
Wireless ATM
Network
Demonstrator
AC204
System for
Advanced Mobile
Broadband
Applications
Advanced Wireless
ATM
Communications
Systems
Objective
Details
Evaluate and
implement a high
speed WLAN for
multimedia
applications and
demonstrate it in
real user trials
Develop and
evaluate a realistic
WATM
transmission
facility at 5 GHz
Demonstrate
mobile user
applications at up
to 34 Mbps and
prove the MBS
concept

Development of
system concept
and testbed
demonstration of
tetherless public
access to B-ISDN
services











Multicarrier modulation
(512 channels + OFDM)
60 GHz band
One base station at 155
Mbps, two portables, one at
34 Mbps and one at 155
Mbps
Data rates from 20 Mbps to
155 Mbps
See previous section
Trial platform of 2 base and
2 mobile stations operating
at 40 GHz
Design state of the art
ASICs
Implement mobility
management and handover
functions
Low mobility terminals
operating at 19 GHz
Data rates of up to 34 Mbps
Transmission range of
100m
Contribution to standards
development
Japanese Wideband Wireless Activities
Table 4.4.1: Proposed MMAC systems and their parameters
MMAC System
Service Area
Connected Networks
Transmission Speed
Terminal Equipment
Mobility
Frequency Bands
Bandwidth
Quality
High-Speed Wireless Access
Indoors and outdoor
Public networks or private
networks
Average 6-10 Mbps
Maximum 25 Mbps
Notebooks and PCs
Stationary or pedestrian
(handovers allowed)
25 or 40 or 60 GHz
500-1000 MHz
bit error rate of 10-6
Ultra High-Speed Radio LAN
Indoor
Private networks only (ATM)
155 Mbps
Desktop PCs and workstations
Stationary only
Relocation handover permitted
60 GHz
1-2 GHz
bit error rate of 10-8
MMAC: Multemedia Mobile Access Communications
Unlicensed PCS Activity (Spectrum
Etiquette)
Three basic Principles:
• Listen before talk (or transmit) LBT Protocol
• Low transmitter power
• Restricted duration of transmissions
Unlicensed National Information
Infrastructure Devices
Table 4.2.1. FCC Requirements for the U-NII Frequency Bands
Band of
operation
Maximum
Tx Power
Maximum PSD
50 mW
Max. Power
with antenna
gain of 6 dBi
200 mW
5.15 - 5.25 GHz
5.25 - 5.35 GHz
250 mW
1000 mW
12.5 mW/MHz
5.725-5.825 GHz
1000 mW
4000 mW
50 mW/MHz
2.5 mW/MHz
Applications:
suggested and/or
mandated
Restricted to
indoor
applications
Campus LANs
Community
networks
Other Remarks
Antenna must be
an integral part
of the device
Compatible with
HIPERLAN
Longer range in
low-interference
(rural) environs.
Issues in a Mobile Network
• Type of roaming
– Intra-Net (802.11)
– Inter-Net (GPRS)
– Inter-Tech (between GPRS and 802.11)
• Type of mobility
– Continual during a move
– Access at different locations
• Type of connection
– With a unique address (mobile IP)
– With any address (cash IP)
• Type of initiation for roaming
– From the terminal
– From th network
Evolving Roaming Related Technologies
• Intra-Net Roaming
– LANE in WATM
– 802.11
– Hiperlan
• Inter-Tech Roaming
– MASE
– Artour
• Inter-Net Roaming
– Mobile-IP
Layers for Implementation
{
Application
Presentation
Session
Transportation
Network
MAC
Physical
TCP
IP
Mobile IP
LC
Mobile Host
M
Local cache
Sender
M
S
Mobile Host
R20
Foreign Agent
inform if possible
Router
R1
Home Agent
R2
R3
R4
“IP in IP” Encapsulation
IP Version number, and other header
fields
Tunnel Source IP address (home agent)
CARE-OF Address (foreign agent)
IP Version number, and other header fields
Original source IP address
Home IP address of mobile host
TCP and rest of packet
Why Client-Server is Important
• Most of the current legacy applications are clientserver
• Facilitates implementation of mobility
• Facilitates interoperability
• Facilitates scaleability
• Can support multiple platforms
• Local optimization of the server to enhance
reliability and availability and results in reducing
costs
Important Client-Server Applications
•
•
•
•
•
Web search,
FTP,
Data base access,
Telnet,
Email
References
•
K. Pahlavan , A. Zahedi, and P. Krishnamurty, “ Wideband Local Access: Wireless LAN and Wireless ATM”, invited
paper, Speical Issue on WATM, IEEE Comm. Soc. Mag., Nov. 1997.
•
K. Pahlavan and A. Levesque, Wireless Information Networks, New York: John Wiley and Sons, 1995.
•
K. Pahlavan, A. Falsafi, G. Yang, “Transmission Techniques for Wireless LANs”, IEEE JSAC, Speical Issue on
Wireless Local Communications, May 1996.
•
K. Pahlavan and A. Levesque, “Wireless Data Communication”, Invited Paper, IEEE Proceedings, Sep. 1994.
•
K. Pahlavan, “Wireless Intra-Office Networks”, Invited paper, ACM Trans. on Office Inf. Sys., July 1988. (also
published as the opening paper in “Advances in Local and Metropolitan Area Networks”, edited by William Stalling,
IEEE Press, 1994)
•
K. Pahlavan, “Wireless Office Information Networks”, IEEE Comm. Soc. Mag, Sep. 1985.
•
K. Pahlavan, T. H. Probert, and M. E. Chase, “Trends in Local Wireless Networks”, Invited Paper, IEEE Comm. Soc.
Mag., March 1995.