Resource Allocation and Power Control for Mobile Relay in TDD-OFDMA Downlink

Dae Wook Byun, Young Min Cho, Dong Ku Kim Yonsei University, School of Electrical and Electronic Engineering

ICCIT 2008

Outline

Introduction System model Proposed schemes

Subchannel allocation scheme MRS power control scheme

Simulation Conclusion

Introduction

Motivation Most of the researches about relay-aided system

have been focused only on the fixed relay station

mobile relay station (MRS) is worth to be considered because it can be used with relatively cheaper cost than that of FRS

Introduction

Goal subchannel allocation and relay power control

to enhance the cell throughput and expand the service coverage

Introduction

Non-transparent RS

System model

Carrier to interference ratio (C/I) reported to BS

BS

MS

RS

System model

Simple-relay aided resource allocation n-th subchannel MS i Time t

instantaneous supportable data rateof the direct path

BS

MS

RS

System model

Simple-relay aided resource allocation

BS

MS

RS

5 b/s,10b/sWorst-link = (1/2)min( 5 , 10 ) = 2.5b/sPer-link = 1/(1/5 + 1/10) = 3.3b/s

Subchannel allocation scheme

OVSA

BS

MS

RS

RS

MS

MS

BS

RS

Subchannel allocation scheme

OVSA

BS

MS

RS

RS

MS

MS

BS

RS

Subchannel allocation scheme

OVSA

BS

MS

RS

RS

MS

MS

BS

RS

Subchannel allocation scheme

ORSA

BS

MRS power control scheme

Simplified on-off mobile relay control (SOMRC) the number of combinations taken into account is

2M+N

N is number of cells M is number of relays within cell

MRS power control scheme

Simplified on-off mobile relay control (SOMRC)

Step1MRS-on

MRS-off

MRS power control scheme

Simplified on-off mobile relay control (SOMRC)

Step2MRS-on

MRS-off

MRS power control scheme

Simplified on-off mobile relay control (SOMRC)

Step3MRS-on

MRS-off

Simulation

19 cells with frequency reuse of 1 and cell radius is 1km

7 clusters using wrap-around cell structure MSs are distributed uniformly in BSs number of MSs per cell is assumed from 1 to 30 number of MRSs per cell is assumed 1, 3, and 6 The MRSs move having random direction and

constant speed of 42 km/h

Simulation

Simulation

Simulation

Simulation

Simulation

Conclusion

This paper proposed to enhance the cell throughput and expand the service coverage for the IEEE 802.16j downlink system with mobile relays

OVSA with SOMRC provided larger cell throughput than OVSA without MRS power control

OVSA with SOMRC scheme showed the best service coverage performance