An Overview and Future Directions on Physical-Layer Security for Cognitive Radio Networks

Abstract

Cognitive radio networks (CRNs) have emerged as a reliable technology to address the problem of spectrum under-utilization. Cognitive radio (CR) is known to be intelligent, as it can sense, learn, and change its transmitting and receiving parameters according to changes in the surrounding environment. These operations are characterized by the CR cognition cycle. During the three stages of cognition, users are vulnerable to several types of attacks on the physical layer. Various types of physical-layer attacks can lead to loss of data security over CRNs. In this article, an overview of physical-layer security (PLS) for CRNs is provided. Some of the major attacks over the physical layer of CRN are presented, such as primary user emulation attack (PUEA), sensing falsification, jamming, and eavesdropping. Moreover, some of the suggested methods to combat these attacks and ensure data privacy are provided. We focus on presenting certain methods to combat eavesdropping. Current challenges and future research directions are included.