IEEE 802.22授权频带多周期循环检测性能分析

Performance Analysis of Spectrum Sensing on Primary Bands in IEEE802.22 WRAN Systems

认知无线电使用动态频率接入,应具备自动检测无线电频谱空洞功能。基于多周期循环检测算法,研究了IEEE802.22WRAN授权用户频带的特征感知方案。其基本思想是利用周期平稳信号的自相关函数以及协方差函数特性,计算自相关值的协方差,比较估计值与门限值,判决原信号是否具有循环平稳性,从而识别出各种信号类型。仿真利用两类授权用户信号特点进行精细感知,并着重分析了循环周期长度和延时等参数对检测性能的影响。结果表明增加计算自相关函数时的循环周期长度或采样点数,降低延时,都有利于信号检测,从而验证了该算法的优良性。

Cognitive radio will be able to seek and use in a dynamic way the frequencies for network access by automatic detection of vacant bands in radio spectrum. This paper focuses on methods for feature sensing of primary bands in IEEE 802.22 WRAN systems. Specifically, multi-cycles detection, based on the correlation and covariance function of the cyclostationary signal, will be investigated. Applying the technique of computing the covariance of the correlation function, the test statistics can be obtained. Compared with the threshold, results can be decided that whether original signal is cyclostationary or not. Finally, this method facilitates the detection of signals by increasing the number of cyclic period or the duration of cyclic period used in the calculation of the correlation function as well as reducing the delay. Simulations in fine sensing by characteristic of primary user signal are presented to confirm the good performance.