Optimization of Cooperative Spectrum Sensing in Cognitive Radio
Optimization of Cooperative Spectrum Sensing in Cognitive Radio
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DOI：
10.1109/tvt.2011.2116815
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发表时间：
2011-02
影响因子：
6.8
通讯作者：
T. Cui;F. Gao;A. Nallanathan
中科院分区：
文献类型：
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作者：
T. Cui;F. Gao;A. Nallanathan
本文研究了两个辅助用户通过中继方式协作的协同频谱感知问题。我们研究了两种协同感知策略，即单元在本地交换数据信息，单元将信息中继到中央控制器。通过平均或峰值功率约束的功能分析，优化了每个SU的继电方案。对于局部协同感知策略，最优中继方案在低信噪比（SNR）区域表现为放大转发（AF），在高信噪比区域表现为解码转发（DF）。讨论了局部协同感知的基本性能限制。对于全局协同感知策略，我们提出了相干感知和非相干感知，这取决于单元是否同步。在相干情况下，设计了一种分散的方法，每个SU在本地优化其中继功能。在非相干情况下，我们使用线性能量组合检测器将继电函数与权系数优化解耦。仿真结果表明，所提出的协议比现有协议具有更好的性能。
In this paper, we consider cooperative spectrum sensing when two secondary users (SUs) collaborate via the relaying scheme. We investigate two cooperative sensing strategies, i.e., SUs exchange data information locally, and SUs relay information to a central controller. The relaying scheme at each SU is optimized via functional analysis with either the average or peak power constraints. For the local cooperative sensing strategy, the optimal relaying schemes look like amplify-and-forward (AF) in the low-signal-to-noise-ratio (SNR) region and behave like decode-and-forward (DF) in the high-SNR region. The fundamental performance limit using local cooperative sensing is discussed. For the global cooperative sensing strategy, we propose both coherent and noncoherent sensing, depending on whether SUs are synchronized. In the coherent case, a decentralized approach is designed, and each SU optimizes its relaying function locally. In the noncoherent case, we use linear energy combination detector to decouple the relaying function from weight coefficient optimization. Simulation results demonstrate that the proposed protocols achieve much better performance over the existing protocols.