1

Wireless ATM networks

new architecture elements and functionality supporting mobility

2

Service scenarios

• wireless LAN networks with dynamically modified structure

• broadband wireless access networks

• wireless point-to-point links

3

Possible R&D directions

• GSM System +– multimedia support– QoS support

ATM

Cell radius& mobility

Bit

rat

e

10 kbps

100 kbps

1 Mbps

10 Mbps

100 Mbps

GSM+WAP

Technocal boundary

WATM

UMTS

• ATM System +– radio access– mobility

4

New requirements for WATM• Wireless access (ETSI BRAN)

• shared medium• relatively high error ratios• relatively low bit rates

• Mobility (ATM Forum)• Location Management (LOC)• Handover Control (HOC) without loosing

connections and with QoS persistence

5

Wireless ATM System

• New components– ATM switch with “M” UNI/NNI interface– ATM base station with “M” UNI/NNI and “W” UNI

interfaces– ATM mobile terminal with “W” UNI interface

+ mobility support software+ radio ports

Wired ATM

ATM Switch

ATM Switch +Mobility Ext

ATM Host/Server

Radiomicrocell 1

Radiomicrocell 2

WATM Terminal

WATM Terminal

UNI

NNI/UNI„M” NNI/ UNI

„W” UNI

„W” UNIStandardATM API

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WATM Radio Access

• PHY Layer• MAC Layer• LLC Layer

MAC

PHY

LLC „W” CTRL

SigVCs Control

Multiplexed data

Radio signal

Upper Layers

User Plane Control Plane(+ Mobility Ext.)

WA

TM

Rad

ioA

cces

s La

yers

7

WATM PHY Layer

• Cell radius:– 50-500 m (microcell or picocell environment)

• Band:– 5GHz Unlicensed NNI band (USA)– "Hiperlan" band (Europe)– in future 20/30 or 60GHz (limited mobility)

• Bit rate:– ~25Mb/s (2-4Mb/s sustained, 5-10Mb/s peek VCs)

• Modulation:– QPSK/GMSK or OFDM

• Access Method:– TDMA/TDD

8

WATM MAC Layer

• Reservation based MAC protocols– Piggybacking– Assigned reservation slots– Contention slots

• Pooling based MAC protocols• Generic frame structure (TDMA/TDD)

Header Data Reservation period

BSMT MTiBS

9

WATM LLC Layer

• Error detection with retransmission (SREJ ARQ)

• Forward error correction

0

200

400

600

800

1000

1200

1400

1600

1800

1000 1500 2000 2500 3000 3500 4000

Avail UBR BW (kbps)

TC

P T

hru

with LLC

without LLC

10

WATM Mobility Support

• Location Management (LOC)• Handover Management (HOC)

11

WATM Location Management• Extended addressing for MTs

– home address (HA)– foreign address (FA)

• Possible solutions• FA of the MT is maintained by its home

ATM switch• Designated LOC servers maintaining HAs

to FAs mapping exists in the system

12

WATM Handover Control

• Possible initiators– MT vs. BS– old-BS vs. new-BS

• Possible strategies– New connection strategy– Path extension strategy– Connection Tree Strategy

WATM Status

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• Projects– Race II– ACTS (Advanced Communications Technologies and Services)

• Magic WAND• AWACS (ATM Wireless Access Communication System)• Samba (System for Advanced Multimedia Broadband

Applications)• MEDIAN

• Standards (ETSI)– HIPERLAN Type 2 – wireless local access– HIPERACCESS – wireless local loop– HIPERLINK – wireless point-to-point link

THANK YOU

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