频谱感知技术是认知无线电关键技术之一。能否正确快速地感知主授权频谱，是认知用户进行通信的前提，也是衡量检测性能的标准之一。考虑衰落信道对检测性能的影响，文中提出一种在多跳认知无线网络中基于空时编码的多簇协作频谱感知方法。具体方案为：首先对认知用户进行分簇，然后根据距离对簇进行分级，最后簇头与它的上一级簇头进行 Alamouti 编码，并将编码后的感知信息通过多跳的方式发送到融合中心，以提高协作频谱感知的检测性能。仿真结果表明：采取多跳多簇认知网络不仅可以有效地减少发送的能量，而且多跳多簇认知网络的跳数和支路数会在一定范围内增强检测性能。同时，采用 Alamouti 编码之后的信道误码率得到了明显改善，检测性能得到大幅提高。%Spectrum sensing is one of the core technology of Cognitive Radio ( CR). Whether the unlicensed spectrum can be sensed quickly and correctly is not only the premise of the communication,but also one of the standard of sensing detection. Considering the noise of fading channel,a method of multi-cluster cooperative spectrum sensing based on space-time coding in multi-hop cognitive radio networks was proposed. The program is shown in detail as follow. First,divide the cognitive users into different clusters. Secondly,classify the clusters based on distance. Next,the cluster head will adopt Alamouti coding with its upper level cluster. At last,the fusion center will get the coding information of sensing results. This program will help to enhance the detection capability. Multi-cluster can reduce the power and sensing time. The simulation result suggests that suggested scheme can not only reduce the energy dissipation and improve the throughput,but also can improve the detection property in a certain scale. After Alamouti coding,the error rate decreases dramatically.
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