Enhanced Throughput Performance under Primary User Emulation Attack in Cognitive Radio Networks by Optimal Threshold Selection Approach

Cognitive radio (CR) provides dynamic spectrum access to combat spectrum scarcity. Due to the unique characteristic of cognitive radio network (CRN) architecture, it allows various unknown wireless devices to opportunistically access the primary user's (PU) spectrum bands which imposes security threats to the network. One of the common threats is a primary user emulation (PUE) attack, where some malicious users try to mimic the primary signal and deceive secondary users (SUs) to prevent them from accessing the vacant PU spectrum bands. In this paper, the throughput performance of a SU has been enhanced under PUE attack by a proposed optimal threshold selection approach that minimizes the total error probability where SU spectrum access is hybrid, i.e., either in overlay or in underlay. An analytical framework for evaluating the throughput of a SU under proposed defense scheme is presented. Impacts of several parameters such as sensing time, attacker's strength and attacker's presence probability on the throughput performance of a SU following the proposed scheme are indicated and compared with conventional scheme. The proposed scheme based on optimal threshold selection outperforms the conventional scheme based on a fixed threshold. The effects of attackers on false alarm probability and total error probability of SU are also indicated. A simulated test bed is developed in MATLAB to validate our analytical results.