wnmc2004 wireless future

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: [email protected]

2.


Introduction

Cellular Wireless Systems and Wireless Networks

Roadmap

Performance Analysis

Requirement Analysis for Next Generation Wireless Systems

Candidate Architectures

Candidate Technologies

Conclusions

Agenda

3.


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.


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.


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.


Wireless Networks PAN – IEEE 802.15

LAN – IEEE 802.11

MAN – IEEE 802.16

7.


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.


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.


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.


11.


Source: I.G. Neemgeers et.al., IST NEXWAY Workshop, 2003

12.


IP CORE

Internet

BROADCAST

WMAN

Fixed LineBackbone

WLAN

CELLULAR

WPAN

Integrated Architecture

13.


Source: I.G. Neemgeers et.al., IST NEXWAY Workshop, 2003

14.


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.


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.


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.


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.


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.


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.


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.


Thank You

wnmc2004 wireless future

Documents