文档介绍：南京邮电大学
硕士学位论文
认知无线电中的协作频谱感知技术研究
姓名:张冰玉
申请学位级别:硕士
专业:信号与信息处理
指导教师:郑宝玉
2011-03
南京邮电大学硕士研究生学位论文摘要
摘要
认知无线电是一种解决频谱稀缺的有效途径,作为下一代网络发展中的关键技术正受
到越来越多的关注,而频谱感知作为认知无线电网络中的重要技术近年来也成为了研究的
热点。协作频谱感知是在单用户频谱感知技术上发展起来的,通过利用认知无线电用户的
分集作用提高感知的准确度和灵敏度。本文在总结了现有各种协作频谱感知方法的基础上,
着重研究了以下问题:
首先,重点研究了采用双门限能量检测的协作频谱感知,分析了一种“β-比”融合
准则,以提高系统感知准确度。理论推导并仿真了感知信道(sensing channel)为 AWGN
信道或 Rayleigh 衰落信道,汇报信道(reporting channel)理想或非理想时的系统性能参数,
并与采用“与”规则和“或”规则融合时的情况做了比较,得出结论:“β-比”融合准则在
提高系统感知准确度和降低传输开销方面都具有较明显的优势。
其次,本文还针对协作频谱感知中存在的异步问题,构建了一种基于异步分布式融合
的协作频谱感知模型,推导了此模型在似然比准则下的最优融合方案,并分析了一种不需
要主用户先验信息的次优方案——最大后验概率(MAP)估计-K 秩规则融合方案。分别对
采用这两种方案时的系统性能进行了理论分析和仿真,仿真结果显示两种方案都能有效提
高频谱感知的可靠性。

关键词:认知无线电,协作频谱感知,双门限能量检测,异步分布式融合,最大后验概率
估计
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南京邮电大学硕士研究生学位论文 ABSTRACT
ABSTRACT
Cognitive radio (CR), an innovative technology to mitigate the spectrum scarcity problem,
is being paid on increasingly attention as a key technology in the next-generation wireless
network. And spectrum sensing, one of the most important issues in works, has e a
hot research topic in recent years. Cooperative spectrum sensing can improve the inference
accuracy and sensitivity by using diversity of CR users. This thesis summarizes existing
cooperative spectrum sensing schemes, and then focuses on the following two issues:
First, and then cooperative spectrum sensing using double threshold energy detection is
investigated. A fusion rule called ‘β-ratio’ rule is analyzed for improving the accuracy of sensing.
The performance parameters of the sensing system whose sensing channel is AWGN channel or
Rayleigh fading channel, and reporting channel is perfect or imperfect are derived and then
simulated, which pared with those of a system based on ‘and’ fusion rule or ‘or’ fusion
rule. The conclusion is that ‘β-ratio’ rule has quite obvious superiority both on improving
sensing accuracy and reducing transmission overheads.
Second, a cooperative spectrum sensing model is propos