基于信道统计特征的认知无线电协作频谱检测

Channel statistics based cooperative spectrum sensing for cognitive radios

针对认知无线电到融合中心间的控制信道为Nakagami-m衰落信道的情况,研究了认知无线电协作频谱检测问题,推导出融合中心利用衰落信道统计特征的似然比协作频谱检测公式。该方法不需要瞬时信道状态信息,简化了协作频谱检测过程,便于实际应用。通过仿真对融合中心的协作频谱检测性能进行了分析,结果表明:利用衰落信道统计特征的似然比协作频谱检测的性能较利用瞬时信道状态信息的似然比频谱检测性能略有下降,但是在高信噪比或衰落不严重的情况下,二者的性能非常接近,认知无线电节点个数对两种频谱检测方法间的性能差距几乎没有影响。

Cooperative spectrum sensing for cognitive radios was studied with the assumption that the control channels between cognitive radios and the fusion center are Nakagami-m fading channels. The likelihood ratio test equation with the knowledge of the channel statistics was derived. With this method, the fusion center can perform cooperative spectrum sensing without the instantaneous channel state information, and the spectrum sensing process is simplified and more suitable for practical applications. The performance of the proposed cooperative spectrum sensing was analyzed through simulation, the results of which show that the performance of the proposed channel statistics based spectrum sensing method degrades performance slightly compared with the channel state information based likelihood ratio test,hut when the average receive SNR is high or the fading effect is weak,the performance of the proposed method can approach that of the channel state information based likelihood ratio test. In addition, the number of cognitive radios has almost no influence on the performance difference between the two methods.