认知无线电带宽频谱感知性能分析及优化

Optimization and Performance Analysis for Bandwidth Spectrum Sensing in Cognitive Radio

为了降低认知无线电中主用户受到的干扰,根据主用户状态的变化,通过将通信带宽分为感知频带和传输频带,建立了次用户在整个帧周期内进行带宽频谱感知的模型.该模型中,次用户在每个帧使用部分带宽进行频谱感知,其余的带宽传输数据.在限制主用户受到的干扰和次用户虚警概率的基础上,通过联合优化感知带宽比和检测概率,最大化次用户的频谱效率.使用MATLAB软件仿真模型的干扰概率和频谱效率,结果表明:相比传统的时间频谱感知,当虚警概率为0.5时,带宽频谱感知能够使主用户受到干扰的概率降低30%;当干扰概率为0.2时,带宽频谱感知能够使次用户的频谱效率提高0.3(bit/s)/Hz.

To decrease interference to primary user （PU） in cognitive radio （CR）, a bandwidth spectrum sensing model of secondary user （SU） over the whole frame was built through dividing the communication bandwidth into sensing frequency band and transmission frequency band, according to the status variation of PU. In this model, SU uses part of the bandwidth to perform spectrum sensing and the rest to transmit data in a frame. Subject to the constraints of the interference to PU and the false alarm probability of SU, the spectrum efficiency of SU was maximized through jointly optimizing sensing bandwidth proportion and detection probability. Using the MATLAB software to simulate the interference probability and the spectrum efficiency, it is found that compared to the conventional time spectrum sensing, the bandwidth spectrum sensing decreases the interference probability to PU by 30% with the false alarm probability of 0.5, and improves the spectrum efficiency of SU by 0.3 （bit/s）/Hz with the interference probability of 0.2.