Relay Selection in Amplify-and-Forward Systems with Partial Channel Information

Zhaoxi FANG  Xiaolin ZHOU  Yu ZHU  Zongxin WANG  

IEICE TRANSACTIONS on Communications   Vol.E93-B   No.3   pp.704-711
Publication Date: 2010/03/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E93.B.704
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Broadcast Systems
wireless relay networks,  amplify-and-forward,  relay selection,  partial channel state information,  

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Selection relaying is a promising technique for practical implementation of cooperative systems with multiple relay nodes. However, to select the best relay, global channel knowledge is required at the selecting entity, which may result in considerable signaling overhead. In this paper, we consider the relay selection problem in dual-hop amplify-and-forward (AF) communication systems with partial channel state information (CSI). Relay selection strategies aiming at minimizing either the outage probability or the bit error rate (BER) with quantized CSI available are presented. We also propose a target rate based quantizer to efficiently partition the SNR range for outage minimized relay selection, and a target BER based quantizer for BER minimized relay selection. Simulation results show that near optimal performance is achievable with a few bits feedback to the selecting entity.