基于Dempster-Shafer证据理论的协同频谱感知算法

Cooperative Spectrum Sensing Algorithm Based on Dempster-Shafer Theory in Cognitive Radio Systems

认知无线电的首要任务是频谱感知,单个认知用户的频谱感知结果容易受到衰落和多径的影响,本文结合证据理论研究了多个认知用户的协同频谱感知问题。为了在融合中心未知先验信息的条件下实现对授权用户的有效检测,文章基于Dempster-Shafer证据理论,对认知用户的本地感知结果提取证据,然后在融合中心进行融合并判决,提出了一种基于Dempster-Shafer证据理论的协同频谱感知算法。仿真结果表明,该算法能够在融合中心未知先验信息情况下,获得较好的频谱感知性能。

In order to enable access to unused licensed spectrum, a cognitive user has to monitor licensed bands and opportunistically transmit whenever no primary signal is detected. However, detection is compromised when a user experiences shadowing or fading effects. In such cases, user cannot distinguish between an unused band and a deep fade. Cooperative spectrum sensing is taken into account and studied in this paper as a means to combat such effects under prior knowledge constrains in the fusion center. A novel cooperative spectrum sensing algorithm based on Dempster-Shafer theory was proposed. In this novel algorithm, the credibility and uncertainty are calculated based on the local sensing result of cognitive radios, then fused at the fusion center using Dempster-Shafer theory. The simulation results show that the performance of the novel algorithm is better under prior knowledge constrains in the fusion center.