基于次用户功率控制辅助的合作频谱感知

Secondary User Power Control Aided Cooperative Spectrum Sensing

传统的合作频谱感知一般将感知环境建模为单级信道,且次用户一般都以相同的发射功率向数据融合中心报告感知数据,难以体现并利用不同次用户感知数据之间的空间分集差异。为解决此问题并有效地设置次用户在感知数据上报阶段的发射功率,该文提出了3种最优功率控制方案,以获得相应设计准则下参与合作感知的次用户最优发射功率。在融合中心理想具备感知信道和报告信道的统计特性时,通过理论推导获得了基于信道统计特性的功率控制闭式解方案;当信道统计特性难以现实具备时,分别获得了基于联合信道统计特性估计的最大特征功率矢量及盲加权多特征功率矢量方案。理论分析和仿真实验表明,在不同的先验信息条件下,3种方案的性能皆远优于缺少功率控制的合作感知方案。

In conventional cooperative spectrum sensing, the signal model is usually simplified as a single-stage channel environment where the Secondary Users （SUs） collect their spectrum data and report to the Fusion Center （FC） with the same transmit power. This hampers the FC from efficiently exploiting the space diversity gain beneath the data of different users. In order to solve this problem and control the user transmit power in reporting their data, three Optimal Power Control （OPC） schemes are proposed. When the Channel Statistic （CS） of the sensing channel and the reporting channel are perfectly known at the FC, a CS Aided Optimal Power Control （CSA-OPC） scheme is derived in closed-form, whereas when the CS is practically unavailable, Principal EigenVector aided OPC （PEV-OPC） and Blindly Weighted Multiple-EigenVector aided OPC （BWMEV-OPC） schemes are developed. Theoretical analysis and computer simulation verify that the propose OPC schemes greatly ameliorate the spectrum sensing performance, compared to the non-OPC aided cooperative spectrum sensing schemes.