电子学报文章格式模板-数据采集与处理.doc

基于截断型序贯检测的协作频谱感知算法( 李明源 李鸥 王勇锋 栾红志 于鹏 （，） 摘要且目标检测性能相同的条件下，相比现有的能量检测算法，所提算法在和两种情况下分别减少了55.86%和37.51%的平均样本数。 关键词 中图分类号：TN92 文献标识码A A Cooperative Spectrum Sensing Algorithm Based on Truncated Sequential Detection Li Mingyuan, Li Ou, Wang Yongfeng, Luan Hongzhi, Yupeng (Institute of Information system Engineering, Information Engineering University, Zhengzhou, 450002, China) Abstract: For cognitive users with low SNR at transceiver front-end, a cooperative spectrum sensing algorithm based on truncated sequential probability radio test (SPRT) is proposed to improve the sensing performance. A split-phase processing method is employed firstly; all the CR nodes involved quantities of its local energy-based sensing samples and compared with specified threshold consequently. Instead of sending all the sensing results of cooperative CR user, only the number of sampling points bigger than the threshold is sent to fusion center serving as local detection statistics, which greatly lowers transmission overhead on common control channel. Gaussian distribution is approximately obtained based on DeMoivre-Laplace theorem and central limit theorem, computation complexity and deriving process of likelihood ratio function is reasonably simplified. Theoretical analysis and simulation results indicate that, compared with existing energy-detection sensing method, the proposed algorithm reduces the average sample number around 55.86% and 37.51% under the conditions of and while the average SNR of CR users is -15dB. Key words: cognitive radio networks; cooperative spectrum sensing; truncated sequential probability radio test; energy detection; average sample number 引 言 随着无线通信技术的迅猛发展，频谱资源匮乏的问题日益显现。然而，美国联邦通信委员会2002发布的研究数据表明，许多授权频段的频谱资源并未得到充分利用。针对这一问题，Joseph Mitola博士首次最先提出了认知无线电[1]（CR, Cognitive Radio）的概念，并受到了业界的广泛关注。作为CR的首要任务和关键技术，频谱感知可以有效的避免对主用户（PU, Primary User）造成干扰，发现频谱空洞进而提高频谱利用率[2]。然而，在实际中，由于诸如多径衰落，阴影效应以及接收机不确定等因素的存在，严重影响了单个CR用户的感知性能。而协作频谱感知可以利用空间分集进一步提高检测性能，是目前最有潜力的一种频谱感知方