关键词: 认知无线网络, 频谱感知, 多相关天线, 平方律合并, 双门限

Abstract: To solve the current contradiction between sensing performance and cooperation overhead of cooperative spectrum sensing, a hierarchical fusion cooperative spectrum sensing scheme based on double thresholds with multi-antenna Cognitive Radios （CRs） is proposed in this paper. Additional improvement of local sensing performance of CRs is provided by taking advantage of space diversity gain for employing Square Law Combining （SLC） with multiple antennas. The local sensing results are divided into one-bit and two-bit decisions by setting thresholds. And then by limiting the lowest number of cooperating CRs through Fusion Center （FC）, CRs make a hierarchical report and Fusion Center （FC） makes a hierarchical fusion based on the sensing report. Simulation results show that the proposed scheme achieves a good tradeoff between sensing performance and communication overhead and is more robust to the distance between double thresholds. Also, when most of the detected values fall between the two thresholds, the probability of sensing failure problem caused by malfunctioning CR is greatly reduced.

Key words: cognitive radio network, spectrum sensing, multiple correlated antenna, square law combining, double thresholds