1

後卓越計畫進度報告楊舜仁老師實驗室2008.01.07

2

Objective Investigate the bandwidth management

mechanisms for IEEE 802.16j networks. The goal of bandwidth management

increase system capacity increase bandwidth utilization increase system throughput reduce new connection blocking probability reduce handoff connection force-termination probability reduce the number of handoffs

3

IEEE 802.16jMultihop Relay Network

The main concept of multihop relay network is to establish relay stations (RS) as relay media between BSs and MSs.

RS: lower power, smaller coverage (relay station cell, RS-cell)

BS: higher power, larger coverage (base station cell, BS-cell)

4

IEEE 802.16j Frame Structure for Data Transmission In IEEE 802.16 networks, each frame has a fixd duration. Each frame contains one downlink and one uplink subframe, and the fra

me is diveided into an integer number of physical time slots, which help to partition the bandwidth easily.

In IEEE 802.16j, the downlink path includes BS to MS, BS to RS and RS to MS, while the uplink path includes MS to BS, RS to BS and MS to RS. The radio resource in IEEE 802.16j may be allotted to RSs in a pre-determined and fixed way.

TimeFrame #n-2 Frame #n-1 Frame #n Frame #n+1 Frame #n+2

Downlink Subframe Uplink Subframe

100 20 25 10 5 20 20

preamble BS bursts

(including BS to MS and BS to RS)

RS #1Bursts(RS to MS)

RS #3Bursts(RS to MS)

RS #4Bursts(RS to MS)

RS #5Bursts(RS to MS)

RS #6Bursts

(RS to MS)FCH

MAP RS #2

Bursts(RS to MS)

Downlink Subframe

5

Bandwidth Repacking

RSj

Bursts

preamble

BS bursts RSi

BurstsRS

Bursts ...FCH

MAP RSj

Bursts

BS

RS-cellRS-cellj

RS-celli

RS-cellRS-cell

BS

RS-cell

RS-celli

RS-cellRS-cell

MS (connection attempt)

preamble

BS bursts RSi

BurstsRS

Bursts ...FCH

MAP

(a)

(c)

(b)

(d)

RS-cellj

MS (with repacking candidate)

MS (connection attempt)connection

attempMS (with repacking candidate)

x

x

Serving repacking candidate

f

Idle time slots

z

yy z

Serving repacking candidate

Serving connection attemp

x-y

6

Problem Statement ofBandwidth Repacking Assume that there are idle time slots in RS-cellm, but no re

packing candidates in RS-cellm due to no MS directly served by BS.

no available time slots

idle time slots

7

Bandwidth Carrying

preamble

BS bursts RSm

BurstsRS

Bursts ...FCH

MAP RSn

Burstsb a

BS RSm RSn

(4)

preamble

BS bursts RSm

BurstsRS

Bursts ...FCH

MAP RSn

Burstsb a

BS RSm RSn

BSRS-cell

RS-celln

RS-cellRS-cell

RS-cellm

(a)

BSRS-cell

RS-celln

RS-cellRS-cell

RS-cellm

(b)

MS

preamble

BS bursts RSm

BurstsRS

Bursts ...FCH

MAP RSn

Burstsb a

BS RSm RSn

(3)

a

b MS

MS

a

b

(1)

(2)

under-loaded over-loaded