非理想信道状态信息对频谱共享认知中继网络性能的影响

Effect of the Imperfect Channel State Information on the Spectrum Sharing Cognitive Relay Networks

在频谱共享认知中继网络中,非理想信道状态信息可能导致次级用户的干扰超过主用户所能容忍的最大干扰值,从而影响到主用户的正常通信。为了衡量次级用户的传输对主用户性能的影响,该文提出了干扰概率这一性能指标。在非理想的信道状态信息条件下,推导了次级用户采用机会中继与选择协作协议时的干扰概率闭式解析式。理论分析表明,从干扰概率角度看,选择协作协议优于机会中继协议,但二者的极限干扰概率相同。此外,在非理想信道状态信息条件下,无论是采用机会中继还是选择协作协议,增加中继数量都会对主用户造成更大的干扰。最后,仿真结果验证了理论分析的正确性。

In spectrum sharing cognitive relay networks,due to the presence of imperfect Channel State Information（CSI）,the interference from the secondary user can be higher than the maximum allowable interference level at the primary user and affect the primary user＇s reliable communication.In order to quantify the impact of the secondary user＇s interference on the primary user,a performance metric termed as interference probability is proposed.The closed-form expressions for interference probability of Opportunistic Relaying（OR） and Selection Cooperation（SC） are derived with imperfect CSI.It is shown that,in terms of the interference probability,the SC is better than the OR.However,the limit interference probability of the OR is identical to that of the SC.Moreover,with imperfect CSI,for both the SC and the OR,increasing the number of relays means a higher interference level on the primary user.Finally,simulation results are presented to verify the analysis.