wnmc2004 wireless future
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1.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Wireless Communications Technology - Now and the Time
to Come
Arpan PalCenter of Excellence for Embedded Systems
Tata Consultancy ServicesKolkata
Email: arpan.pal@tcs.com
2.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Introduction
Cellular Wireless Systems and Wireless Networks
Roadmap
Performance Analysis
Requirement Analysis for Next Generation Wireless Systems
Candidate Architectures
Candidate Technologies
Conclusions
Agenda
3.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Wireless is the next giant leap in information services. The new paradigm for connectivity enables business to operate
• faster• better• more cost effectively• and more profitably
through the use of • always on, • always connected, and • always available content and applications.
With the tremendous increase in wireless LANs, Mobile phones, PDAs, and other mobile devices, the merging of computation and telecommunication technologies is a fundamental part of modern society.
Introduction
4.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Cellular Wireless Systems Roadmap
9.6 k
64 k
384 k
1000 k
2000 k
5000 k
1995 2000 2005
AMPSTACS NMT
IS136GSM
IS95A
IS95BGSM-GPRS
1980
CDMA2000W-CDMAUMTS
4G3G2.5G2G1G
???
5.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Speed, kbps2G
CDMA 2.5GGPRS, CDMA 2000
EDGEUMTS
Messaging/Text AppsVoice/SMS
Location ServicesStill Image TransfersInternet/VPN Access
Database AccessDocument TransferLow Quality Video
High Quality Video
9.6 14.4 28 64 144 384 2000
Performance Comparison of Cellular Systems
6.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Wireless Networks PAN – IEEE 802.15
LAN – IEEE 802.11
MAN – IEEE 802.16
7.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Performance Comparison
Stationary 0 kmph
Near Stationary 0-1 kmph
Nomadic
Quasi-stationary
Pedestrian < 10 kmph
Vehicular <100 kmph
High-speed vehicular
<250 kmph
GSM, EDGE
Co rD EC T
DECT
WCDMA
IEEE 802.11a/b/g
IEEE802.16
BLUETOOTH
DECT
Mobility
Vehicular
Pedestrian
Nomadic
Stationary
0.1 1.0 1.2 2.0 50 150
DATA RATES (rates in Mbps)
LOCAL AREAPERSONAL /HOMEAREA
REGIONALCELLULAR
METROPOLITAN AREACOVERAGE
8.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Future Wireless System Requirements
PowerConsumed
on user devices
SECURITY
INTEROPERABILITY
TRAFFIC TYPE
COMPLEXITY
QoSCAPACITY
COVERAGE AREA
MOBILITY
DATA TYPE
NETWORK
COMM.SYSTEM
• Low Cost
• Infra-structure Re-use
• Personal Networks
• Large coverage @ high mobility
• High Data Rate @ short distance
• Seamless Roaming and Hand-off
• QOS
• Security
• Killer Applications
• Flexible / Modular Inter-operable systems
9.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Application View
WIRELESS COMMUNICATION
WPAN WLAN WMAN
PERFO
RM
AN
CE
VOICE
DATA
MULTIMEDIA
MOBILITY CONNECTIVITY
IMPORTANCE
Ease of use
Simplicity
Performance
Functions
Aesthetics
Personalization
User View
Courtesy: Prof. Ramjee Prasad, Aalborg University, Denmark
Requirements
10.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
11.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Source: I.G. Neemgeers et.al., IST NEXWAY Workshop, 2003
12.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
IP CORE
Internet
BROADCAST
WMAN
Fixed LineBackbone
WLAN
CELLULAR
WPAN
Integrated Architecture
13.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Source: I.G. Neemgeers et.al., IST NEXWAY Workshop, 2003
14.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Future Wireless Technologies
WCDMABest on signal fading
Worst on multipath interferenceGood on intercell interference
OFDMBest on multipath interferenceBad on intercell interference
Worst on signal fading
MC-CDMAOptimal tradeoff among multipath interference, intercell interference,
and signal fading
MIMO-OFDMBest on signal fading
Best on multipath interferenceBad on intercell interference
Smart Antenna Arrays
• MIMO-OFDM and MC-CDMA for large distance• UWB for short distance
UWBVery High Speed (450 Mbps)
Small DistanceMinimal Interference
Robust to signal fadingPosition Location
15.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Orthogonal Frequency Division Multiplexing (OFDM) Systems
• Robustness to ISI through Cyclic Prefix
• Guard Interval reduces throughput
• Intra-symbol Interference is not removed
• Channel estimation is simple but is severely effected by noise.
• Noise cancellation schemes need to be applied before channel estimation
• Large Envelope Fluctuation (PAPR)
• Imposes severe constraint on RF front-end
• Careful coding / dynamic constellation selection need to be explored
16.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Multiple Input Multiple Output (MIMO) Systems
• MIMO advantageous at high SNRs, high data rates, good spatial conditioning
• Adaptive Antenna Processing Benefits
• Selective Gain Increased Range & Coverage
Increased Data Rates
Reduced System–wide Uplink Noise
Improved Uplink Multipath Immunity
Improved Co–existence Behavior
• Interference Mitigation Improved Signal Quality
Maintained Quality with Tightened Reuse
17.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Multicarrier CDMA systems (MC-CDMA)
• DSSS Spreading (CDMA) followed by Multi-carrier modulation
• Cell capacity comes from CDMA
• Multi-user handling from CDMA
• Narrowband Interference tolerance comes from Multi-carrier modulation
(equivalent to OFDM)
18.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
QoS and Security• Quality-of-Service (QoS)
• Stringent QoS requirements for providing sustained data-rate
• Quality of services is constrained by the physical resources• Throughput• Latency• Jitter• Reliability
• Security• Wireless Security, as it exists now is quite fragile• Problem compounded by unrestricted accessibility in wireless environment • Design goals
• Mutual authentication and privacy• Efficiency (speed, economy) in associated messaging• IP-centric solution comprising proven elements
19.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Future Implementation Technologies – Software Defined Radio (SDR)
Drivers
An ever expanding set of ‘contexts’
Adaptive Embedded
Telecom
•Active Networks•BS Adaptivity
•Handheld •BS Frontend
•Software Defined Radio
Courtesy: Dr. P.S.Subramaniam, TCS
20.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Conclusion
Drivers for next generation Wireless Networks
• Personal Networks (PN)
• Killer Applications
• Combination of OFDMA and MC-CDMA
• Adaptive Antenna processing and MIMO systems
• UWB for PANs
• QoS and Security aspects reusing knowledge from existing Wireless
Standards
• SDR concepts for implementation – Reconfigurable Systems
21.
Arpan Pal, WNMC 2004Arpan Pal, WNMC 2004
Thank You
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