基于可靠次用户信息的协作频谱感知算法研究

摘要

对认知无线电系统最基本要求之一就是次用户必须有能力以高的精确率来确定主用户是否存在.而以前对认知无线电频谱感知的研究表明:在实际认知网络中次用户之间的相互协作可以提高其频谱检测性能.然而,对于协作频谱感知而言,随着协作次用户数目的增加,势必会增大用于传输本地检测结果到融合中心的专用控制信道带宽,从而增加系统开销.该文在控制信道带宽有限的约束条件下,提出一种通过考虑可靠次用户信息的协作频谱感知算法来进一步改善频谱检测的性能.该算法的基本思想:只有具有可靠的本地检测结果的次用户才发送自己的检测结果到融合中心,否则,该次用户不发送任何信息.同时,对提出的该算法在理论上进行了推导,通过仿真结果表明:在控制信道带宽受限的约束下,相比于传统的“或”门协作频谱感知算法,提出的算法能够大大改善对主用户的检测性能.%One of the main requirements of cognitive radio systems is the ability to detect the presence of the primary user with precise accuracy. Previous works on the issue of detection for cognitive radio show that cooperating secondary users in the network can improve spectrum detection performance in practical situations. However, for the cooperative spectrum sensing, a dedicated control channel bandwidth, which transmits the local detection decisions of Secondary Users (SUs) to the data fusion, becomes larger with the number of secondary users increases. To improve further the performance of cooperative spectrum sensing under dedicated control channel bandwidth-limited constraints, a cooperative spectrum sensing is proposed based on reliable secondary user information. More specifically, only the SUs with reliable information are allowed to send their local decisions to the date fusion otherwise the other will send nothing. Furthermore, the performance of the suggested scheme is derived and the numerical results are given. The analysis results indicate that under bandwidth-limited constraints, the sensing performance of suggested scheme outperform the conventional OR cooperative spectrum sensing.