A simple amplify-and-forward opportunistic relaying based on outdated channel state information  

作　　者：WANG Chao DENG Ke LI YuBo YIN QinYe ZHUANG LiLi 

机构地区：[1]School of Electronic and Information Engineering,Xian Jiaotong University [2]China Taiyuan Satellite Launch Center

出　　处：《Science China(Information Sciences)》2014年第6期1-14,共14页中国科学（信息科学）（英文版）

基　　金：supported by National Natural Science Foundation of China(Grant Nos.60971113,61172093,61071216,61071125);National Science and Technology Major Project of China(Grant No.2010ZX03003-002)

摘　　要：Opportunistic relay selection（ORS）is a promising approach for cooperative communications owing to its low complexity by activating only the best relay.However,in mobile scenarios,the channel state information（CSI）estimated in relay selection may be different from the actual CSI employed in data transmission due to relatively fast varying channels,i.e.,CSI is outdated,which may lead to incorrect relay selection,and hence system performance deteriorates.To address the problem,this paper designs a relay selection strategy with instaneous and statistical CSIs in amplify-and-forward（AF）cooperative networks whose instantaneous CSIs of two hops employed in relay selection are both outdated.Based on high signal-to-noise ratio（SNR）analysis,we propose a distinctive relay selection strategy which can be described as selecting the relay with the asymptotic optimum average symbol error probability（SEP）and outage probability at high SNR.The corresponding asymptotic outage probability and SEP performance analysis are also provided.Finally,simulation results not only validate our theoretical analysis,but also show that in asymmetrical outdated CSI scenarios,the proposed strategy achieves better performance than existing relay selection strategies at medium and high SNR values.Opportunistic relay selection（ORS）is a promising approach for cooperative communications owing to its low complexity by activating only the best relay.However,in mobile scenarios,the channel state information（CSI）estimated in relay selection may be different from the actual CSI employed in data transmission due to relatively fast varying channels,i.e.,CSI is outdated,which may lead to incorrect relay selection,and hence system performance deteriorates.To address the problem,this paper designs a relay selection strategy with instaneous and statistical CSIs in amplify-and-forward（AF）cooperative networks whose instantaneous CSIs of two hops employed in relay selection are both outdated.Based on high signal-to-noise ratio（SNR）analysis,we propose a distinctive relay selection strategy which can be described as selecting the relay with the asymptotic optimum average symbol error probability（SEP）and outage probability at high SNR.The corresponding asymptotic outage probability and SEP performance analysis are also provided.Finally,simulation results not only validate our theoretical analysis,but also show that in asymmetrical outdated CSI scenarios,the proposed strategy achieves better performance than existing relay selection strategies at medium and high SNR values.

关 键 词：relay selection outdated CSI AMPLIFY-AND-FORWARD outage probability symbol error probability 

分 类 号：TN929.5[电子电信—通信与信息系统] TN916.427[电子电信—信息与通信工程]