Semi-Distributed User Selection Scheme in Decode-and-Forward Systems
Taiyi Zhang · Xi'an Jiaotong Daxue xuebao · 2009
A semi-distributed user selection scheme(SDUS scheme) is proposed to reduce the high complexity in conventional user selection schemes in decode-and-forward(DF) systems.A decision threshold for relay selection is introduced to maximize the instantaneous mutual information of the system.Based on the threshold,the cooperative set is generated.The destination node selects the node with the best channel quality from the cooperative set and the source(when the cooperative set is null) as the cooperative node.The SDUS scheme not only reduces the computational complexity of the system significantly,but also improves the outage performance.Simulation results show that,when the signal-to-noise ratio is 20 dB and the number of relay nodes is 120,the computational cost of the SDUS scheme is just about 39.5% and 51.1% of those of the opportunistic relaying scheme and the selection cooperation scheme,respectively.