认知无线电合作频谱感知技术研究

发布时间：2019-02-15 15:38

【摘要】：认知无线电技术是无线电发展史上的一个新的里程碑,可以有效的解决无线频谱资源日益紧张与固定频谱分配政策之间的矛盾。在认知无线电网络中,认知用户需要持续监听主用户频谱的出现,频谱感知成为了认知无线电技术的前提和基础。由于阴影和多径衰落的影响,单用户检测可靠性非常低。本文主要研究了认知无线电合作频谱感知技术。首先,本文对传统的能量检测、匹配滤波检测、循环平稳特征检测等单用户检测方法进行了总结和分析,单用户本地检测无法满足对检测可靠性和快速性的要求。合作检测能够提高认知网络的整体检测性能,但引入合作却加大了频谱检测的技术难度和运算复杂度。其次,本文分析了一种基于放大转发协议的合作频谱感知技术,建立了两个认知用户的合作网络模型。通过两个认知用户之间的合作,能够减少多径衰落和阴影效应所带来的单用户检测的不确定性。通过合作可以减少对主用户的检测时间,增加认知网络的灵活性。数值解析结果表明,合作频谱感知技术能够有效提高认知用户对主用户的检测概率,具有更加可靠的检测性能。最后,在分布式合作频谱感知基础上,研究了一种通过等增益加权的方式进行数据融合的合作频谱感知技术。并且将加权融合的整体检测性能与传统的单用户能量检测法和或准则检测法进行了对比。数值解析结果表明,加权融合下的整体检测性能要明显优于单用户能量检测法和或准则检测法的检测性能。
[Abstract]:Cognitive radio technology is a new milestone in the history of radio development. It can effectively solve the contradiction between the increasing shortage of wireless spectrum resources and the policy of fixed spectrum allocation. In cognitive radio networks, cognitive users need to continuously monitor the main user spectrum, spectrum sensing has become the premise and foundation of cognitive radio technology. Because of the influence of shadow and multipath fading, the reliability of single user detection is very low. This paper mainly studies the cooperative spectrum sensing technology of cognitive radio. Firstly, the traditional single user detection methods, such as energy detection, matched filter detection and cyclic stationary feature detection, are summarized and analyzed in this paper. Single user local detection can not meet the requirements of reliability and rapidity of detection. Cooperative detection can improve the overall detection performance of cognitive networks, but the introduction of cooperation increases the technical difficulty and computational complexity of spectrum detection. Secondly, this paper analyzes a cooperative spectrum sensing technology based on amplification and forwarding protocol, and establishes a cooperative network model for two cognitive users. Through the cooperation between two cognitive users, the uncertainty of single user detection caused by multipath fading and shadow effect can be reduced. Cooperation can reduce the detection time of primary users and increase the flexibility of cognitive networks. Numerical analysis results show that cooperative spectrum sensing technology can effectively improve the detection probability of cognitive users to primary users and has more reliable detection performance. Finally, on the basis of distributed cooperative spectrum sensing, a cooperative spectrum sensing technique based on equal gain weighting is studied. The global detection performance of weighted fusion is compared with the traditional single user energy detection method and or criterion detection method. Numerical results show that the overall detection performance of weighted fusion is better than that of single user energy detection method or criterion detection method.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TN925

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