Cognitive radio (CR) is a flexible wireless network that can solve the scarcity and underutilization problem of the spectrum by permitting unlicensed users to access licensed bands. The dynamic nature of CR makes it more vulnerable in terms of security. This paper’s emphasis is on the primary user emulation attack, which poses a severe threat to the spectrum sensing operation of CR. In this attack, a malicious user imitates the signal characteristics of a licensed user (primary user) to disguise its true identity. Although many survey papers enhance our knowledge of cognitive radio security, this paper is an attempt to culminate new findings with the old ones to keep up the pace of the research community. Finally, the paper summarizes with some recommendations and future strategies pertinent to energy-efficient and flexible security methods for next-generation wireless systems.

认知无线电（CR）是一种灵活的无线网络，它可以通过允许无执照用户访问许可频段来解决频谱的稀缺性和利用率不足的问题。CR的动态性质使其在安全性方面更加脆弱。本文的重点是主要用户仿真攻击，这对CR的频谱感知操作构成了严重威胁。在这种攻击中，恶意用户模仿了许可用户（主要用户）的信号特征，以掩饰其真实身份。尽管许多调查论文增强了我们对认知无线电安全性的了解，但本文试图将新发现与旧发现结合起来，以跟上研究领域的步伐。最后，