Cooperative spectrum sensing (CSS) is a technique where multiple cognitive radio users cooperate among themselves to make binary decisions about the presence of a primary user. The single cognitive user often faces the hidden terminal problem. However, CSS tackles this problem by sending local sensing-based decisions to the fusion centre. A major drawback of conventional energy detection is the poor performance at low SNR regime. In this work, likelihood ratio statistics is considered as a test-statistic due to its highest statistical power. An improved likelihood ratio statistic-based CSS scheme is proposed by considering several past sensing events. The proposed scheme mitigates the poor detection at low SNR regime and misdetections arising due to sudden drops in signal energy. Furthermore, the generalised Byzantine attack is taken into account considering a security aspect. The proposed scheme is also shown to outperform Anderson Darling-based malicious user detection in CSS at a low SNR regime. The proposed scheme is verified and validated over empirical spectrum data. The performance improvement is at the cost of computational time, which in practice is very low and is justified by the significant performance improvements of the proposed scheme at low SNR regime.

中文翻译：

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改进的基于似然比统计的认知无线电协作频谱感知

合作频谱感测（CSS）是一种技术，其中多个认知无线电用户之间相互合作以就主要用户的存在做出二进制决策。单个认知用户经常面临隐藏的终端问题。但是，CSS通过将基于感知的本地决策发送到融合中心来解决此问题。常规能量检测的主要缺点是在低SNR情况下性能较差。在这项工作中，由于似然比统计量具有最高的统计能力，因此被视为检验统计量。通过考虑一些过去的感知事件，提出了一种改进的基于似然比统计的CSS方案。所提出的方案减轻了在低SNR状态下的不良检测以及由于信号能量的突然下降而引起的误检测。此外，考虑到安全性方面，考虑到了普遍的拜占庭式攻击。在低SNR的情况下，拟议的方案还表现出优于CSS中基于Anderson Darling的恶意用户检测。该方案在经验频谱数据上得到了验证和验证。性能的提高是以计算时间为代价的，在实践中这是非常低的，并且可以通过所提出的方案在低SNR体制下的显着性能提高来证明其合理性。