Femtocell网络中基于双门限的两层协作频谱感知技术

在Femtocell和Macrocell构成的两层异构网络中，前人提出运用认知无线电的技术来解决网络中存在的干扰问题，但大多数研究主要集中在频谱资源的管理上，没有提出高效的频谱检测方法。本文结合认知无线电中频谱感知技术提出了基于双门限的两层协作频谱感知，检测出空洞的频谱资源分配给Femtocell用户使用，既能提高频谱资源的利用率，又能有效的抑制Femtocell与Macrocell之间的干扰。文中推导出了Femtocell用户基于双门限的两层频谱感知的检测概率和虚警概率，给出了Femtocell网络中感知信息两比特编码的融合准则和基于双门限的两层协作频谱感知的具体实施方法。仿真结果表明，所提算法能够有效提高Femtocell用户的频谱检测概率，通过对感知信息进行两比特编码，再将编码后的信息发送至融合中心进行融合，能够有效的提高整个系统的检测性能，抗噪声能力强。 

Two-tier cooperative spectrum sensing technology based on double thresholds in femtocell network

In the two-tier network constituted by femtocell and macrocell, predecessors put forward using the cognitive radio technology to solve the problem of interference existing in the network. However, most studies just focus on the management of spectrum resources, and have not provided efficient spectrum detection methods. A two-tier cooperative spectrum sensing is prosposed based on double thresholds combined with the spectrum sensing technology in cognitive radio. By allocating the empty spectrum resources to the femtocell users, the proposed algorithm improves the utilization of spectrum resources, and suppresses the interference between femtocell and macrocell effectively. For the femtocell users, this paper derives the detection probability and false alarm probability of two-tier spectrum sensing based on double thresholds. A two-bit-coding fusion rule of sensing information is proposed for the femtocell network. At the same time, the specific implementation steps are given for the two-tier cooperative spectrum sensing based on double thresholds. Simulation results show that the proposed algorithm can effectively improve the detection probability of single femtocell user. It also shows that the two-bit-coding of the sensing information and the encoded information fusion in the center can effectively improve the detection performance and anti acoustic performance of the system.