基于中继选择的协作频谱感知技术研究

发布时间：2018-02-28 02:52

本文关键词： 认知无线电协作频谱感知中继选择平均漏检概率　出处：《西安电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：现代社会中,由于无数科研人员的不懈努力,无线通信领域的诸多难题被逐一攻克,人类的沟通与交流也因此变得更加快捷。然而,对更高资源利用率、更快数据处理速率和更强系统可靠性的需求,与匮乏稀少且不可再生的频谱资源客观现状的这对矛盾日益突出,频谱利用率低下已然成为无线通信技进一步发展的瓶颈。于是,认知无线电技术应运而生。该技术能够使认知用户自身主动检测并查找可用的频段资源,在不影响授权用户正常通信的情况下使用授权频段进行通信,以提高频谱利用率。因此,认知无线电技术成为新一代移动通信技术中探求频谱性质、高效利用资源的重要技术基础。在认知无线电技术中,认知用户使用授权频谱的重要前提是对频谱资源迅速且精准的感知,所以频谱感知就成为研究认知无线电首先需要解决的关键问题。另外,基于中继的协作通信技术可以通过多个节点的空间分集,增加系统容量并提高系统性能。因此,将基于中继的协作通信技术应用至频谱感知系统中构造协作频谱感知系统,可以令认知无线电系统的频谱检测能力获得极大提高。本文主要研究基于中继选择的协作频谱感知技术。首先,简要介绍了认知无线电和频谱感知的基本概念和发展情况;其次,阐述了协作频谱感知技术的理论基础,包括基本理论、频谱感知算法和信息融合标准等;接下来,针对存在多个中继的认知系统,重点研究采用不同中继选择策略的协作频谱感知方案对检测性能的影响。首先研究了基于全局中继选择策略的协作频谱感知系统,针对中继放大转发增益可变方案复杂程度高的问题,为了便于工程应用,提出一种基于固定增益的最优中继选择方案,并分析该方案在基于能量检测的系统检测性能,推导出平均漏检概率的理论表达式及闭式下界,全面的仿真结果证明理论分析的正确性,同时还讨论了参与选择的中继数目对平均漏检概率的影响;其次,对增益可变的基于部分中继选择策略的协作频谱感知系统进行了讨论,针对其能耗高实用性差的缺点,提出了一种基于固定增益的最优中继选择方案,并进行了详细的理论分析及全面的仿真实验,结果表明当参与选择的中继个数达到两个时,系统将获得良好的检测性能,可以在提高该方法实用性的同时大大降低能量损耗。
[Abstract]:In modern society, thanks to the unremitting efforts of countless researchers, many difficult problems in the field of wireless communication have been solved one by one, and human communication and communication have become more rapid. The need for faster data processing speed and greater system reliability is increasingly contradictory to the objective status quo of scarce and non-renewable spectrum resources, and the low spectral efficiency has become the bottleneck of the further development of wireless communication technology. Cognitive radio technology emerges as the times require. This technology enables cognitive users to actively detect and find available frequency band resources, and use authorized frequency bands to communicate without affecting the normal communication of authorized users. Therefore, cognitive radio technology has become an important technical foundation for exploring spectrum properties and utilizing resources efficiently in the new generation of mobile communication technology. The important premise for cognitive users to use authorized spectrum is to perceive spectrum resources quickly and accurately, so spectrum sensing becomes the first key problem to be solved in the study of cognitive radio. The cooperative communication technology based on relay can increase system capacity and improve system performance through spatial diversity of multiple nodes. Therefore, cooperative communication technology based on relay is applied to construct cooperative spectrum sensing system in spectrum sensing system. This paper mainly studies cooperative spectrum sensing technology based on relay selection. Firstly, the basic concepts and development of cognitive radio and spectrum sensing are briefly introduced. Secondly, the theoretical basis of cooperative spectrum sensing technology is expounded, including the basic theory, spectrum sensing algorithm and information fusion standard. The influence of cooperative spectrum sensing schemes based on different relay selection strategies on detection performance is studied. Firstly, cooperative spectrum sensing systems based on global relay selection strategies are studied. In order to facilitate engineering application, an optimal relay selection scheme based on fixed gain is proposed to solve the problem of high complexity of relay amplification and forwarding gain variable scheme, and the performance of the scheme in system detection based on energy detection is analyzed. The theoretical expression and the closed lower bound of the average missed detection probability are derived. The simulation results show that the theoretical analysis is correct. At the same time, the influence of the number of relays involved in the selection on the average missed detection probability is also discussed. Secondly, The cooperative spectrum sensing system with variable gain based on partial relay selection strategy is discussed. An optimal relay selection scheme based on fixed gain is proposed to overcome the disadvantages of high energy consumption and poor practicability. A detailed theoretical analysis and a comprehensive simulation experiment are carried out. The results show that when the number of selected relays reaches two, the system will obtain good detection performance, which can greatly reduce the energy loss while improving the practicability of the method.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN925

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