认知无线电论文：基于双阈值的认知无线电协作频谱检测技术研究

认知无线电论文：基于双阈值的认知无线电协作频谱检测技术研究

【中文摘要】频谱检测是实现认知无线电的前提,是认知无线电的的核心技术之一。目前对频谱检测的研究主要有单节点检测和多节点协作检测,协作检测可以通过融合多个认知用户的感知信息更可靠的判断频谱占用情况。为了进一步提升频谱检测性能,本文在协作检测及综合判决算法方面进行了深入研究,主要工作集中在以下方面。首先简单介绍了认知无线电技术的发展概况,接着对频谱检测的概念、国内外研究现状、性能评价进行了详细阐述,然后分析了常见的单节点检测方法,包括主用户发射端检测和主用户接收端检测。由于单节点检测易受干扰的弊端,引入了多节点协作检测,研究了协作检测的硬判决融合算法和软判决融合算法,并且通过仿真实验比较分析了各种经典算法的检测性能。在软判决融合检测算法方面,研究了协作检测中的拔河准则融合算法,仿真分析了其检测性能,并且针对该算法可靠性相对较低的缺陷,提出了一种改进算法,即为了进一步提高可靠性,在可信度因子中引入了本地检测概率；为了减小次要用户对主用户的干扰并降低误码率,对拔河准则算法的门限值设置方式进行了改进,且提出了一种新的性能指标：相撞概率与限用概率,作为对主用户干扰评价标准,最后对系统各节点在不同SNR值下进行了仿真,结果验证了改进的有效性。在硬判决融合检测算法方面,提出了一种基于双阈值的“使用闲置率”准则协作检测算法,该算法在本地检测

中采用基于双阈值的能量检测方法,融合判决中心采用灵活性较高的“使用闲置率”准则检测,并且通过权值的更新筛选用户。仿真实验表明它不仅能够在噪声不确定的情况下进行有效检测,而且能有效降低传输的bit数,相对于传统检测算法在一定程度上提高了检测概率。

【英文摘要】As one of the key technologies, spectrum sensing is the first step for realization of cognitive radio. Now the research on spectrum sensing technology is mainly focused on the field of single node spectrum detection and multi-node spectrum detection. The service condition of the spectrum can be judged accurately by dealing with the detection information of cognitive users for the cooperative detection. In order to improve the spectrum detection performance, the cooperative spectrum detection and decision fusion algorithm are studied further based on analyzing the existing research results, and the main work of this thesis is as follows.In this thesis, firstly, the developing summary of cognitive radio is introduced; secondly, the technology of spectrum sensing is presented detailedly through the concept of spectrum sensing, the study status at home and abroad, and performance assessment. And then, single-user local spectrum sensing method is analyzed, including the transmitter spectral detection and receiver

spectral detection. In order to deal with the limitation of individual node spectrum sensing, cooperative spectrum sensing is introduced, and several conventional soft decision methods and hard decision methods in cooperative spectrum sensing are discussed in this thesis. The detection performance of various classical algorithms are compared and analyzed by the simulation.For the soft-decision fusion algorithm, the tug-of-war-based cooperative spectrum sensing is improved in this thesis. In order to further improve reliability, the probability of local detection is used in credibility factor; to reduce the interference between the secondary user and the authorized user and low the BER, the threshold of

tug-of-war-based cooperative spectrum sensing is improved in this thesis. A kind of performance evaluation standard, which are pcollision probability and limit-using probability, is proposed and used. Effectiveness of its improvement is proved by the simulation under each node with different Signal to Noise Ratio.For the hard-decision fusion algorithm, a novel “use-to-idle ratio” rule cooperative spectrum sensing based on double-threshold for cognitive radio is proposed in this thesis. In this algorithm, the energy detection method based on double threshold is used in local detection and the “use

idle rate” rule detection algorithm with high flexibility is adopted by the fusion center, selecting users through updating the weights. Compared to traditional detection algorithm, this algorithm can effectively reduce the bit numbers of the transmission and increase the detection probability in some degree.

【关键词】认知无线电 协作检测 双阈值 拔河准则 “使用闲置率”准则

【英文关键词】cognitive radio cooperative spectrum sensing double-threshold tug-of-war rule “use-to-idle ratio” rule

【目录】基于双阈值的认知无线电协作频谱检测技术研究要6-7

Abstract7

第一章 绪论11-19

摘

1.1 认知

无线电研究背景及其意义11-1212-1812-13

1.2 国内外的研究现状

1.2.1 认知无线电的概念及其发展概述1.2.2 认知无线电的研究现状13-14

1.2.3 认

知无线电中频谱检测技术研究现状14-18要内容及安排18-1919-39

1.3 本文研究的主

第二章 认知无线电的频谱检测技术

19-20

2.2 频谱检测系

2.1 频谱检测技术概述

统性能评价20-2121-2725-26

2.3 主用户发射端频谱检测技术

2.3.2 匹配滤波器检测

2.4 主用户接

2.3.1 能量检测21-25

2.3.3 周期平稳特征检测26-27

收端频谱检测技术27

27-282.4.1 本振泄露功率检测

2.5 单节点频谱检测技

2.6.1

2.4.2 干扰温度检测27-28

术比较282.6 多用户协作频谱检测技术28-38

2.6.2 协作检测的有效性

30-32

单用户频谱检测的弊端2929-30

2.6.3 协作检测的系统结构2.6.4 软判

2.6.6

决融合算法32-342.6.5 硬判决融合算法34-37

2.7 本章小结

软硬判决融合算法性能比较37-3838-3939-4939-42算法39-4242-48

第三章 拔河准则协作检测算法研究及改进3.1 拔河准则协作检测算法的分析与研究3.1.1 检测模型39

3.1.2 本地检测及拔河准则

3.2 拔河准则协作检测算法改进3.2.1 检测模型42-43

3.2.2 可信度因子及拔

3.3

河准则的改进43-46本章小结48-4949-62

3.2.3 仿真实验及分析46-48

第四章 基于双阈值的协作频谱检测技术研究

4.2

4.1 协作检测面临的关键问题探讨49-50

4.2.1 本地检测模型

检测系统模型及理论分析50-5650-51

4.2.2 基于双阈值认知用户分区51-524.2.3

控制信道的信息传送开销52-54限的设定54-5555-56

4.2.4 信任度因子及判决门

4.2.5 “使用闲置率”准则融合检测算法

4.3.1 DTRSD算法

4.3 DTRSD算法的实现56-58

实现的流程图56-5757-58

4.3.2 DTRSD算法数值分析

4.4.1 参数设置

4.4 仿真实验及分析58-61

58-5961-6265-70

4.4.2 算法仿真分析59-61结论附录

62-6470-71

致谢64-65

4.5 本章小结参考文献

攻读硕士学位期间发表的论文及科

研成果71

58-5961-6265-70

4.4.2 算法仿真分析59-61结论附录

62-6470-71

致谢64-65

4.5 本章小结参考文献

攻读硕士学位期间发表的论文及科

研成果71

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