D-DB and D-RRDB Relaying with D-DQE Relay Network

Yaser FAEDFAR  Mohd Fadzli Mohd SALLEH  

IEICE TRANSACTIONS on Communications   Vol.E97-B   No.2   pp.495-503
Publication Date: 2014/02/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E97.B.495
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
wireless relay systems,  decode-and-forward,  distributed beamforming systems,  relay rejection,  

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In this study, a new method for Decode-Distributed Beamforming (D-DB) relaying is proposed. Each relay node decodes the source symbol by maximum likelihood detection. The detected symbol is entered into the stored Quantized Equal-gain (QE) codebook, where the label of the phase region is provided by a feedback link from the destination node. Therefore, the proposed relay network forms a Decode-Distributed QE (D-DQE) relay network. The performances of the D-DQE codebooks are examined by Monte-Carlo simulations, in which the feedback links and channel estimations are assumed to be error-free. The simulation results reveal that the symbol error rates of the D-DQE relay system improve the error performance of the QE codebooks when relay nodes are close to the source node. When error-free feedback bits are provided, the performance of the proposed D-DQE is better than that of Alamouti's Decode-Distributed Space-Time Coding (D-DSTC) relay network. The weakest relays are rejected to improve the performance of the D-DQE codebooks and reduce the number of feedback bits. This relay network is called Decode-Relay Rejection for Distributed Beamforming (D-RRDB) relay networks.