A single iteration belief propagation algorithm to minimize the effects of primary user emulation attacks

This paper presents a method to alleviate the effects of primary user emulation attacks in cognitive radio (CR) networks. The proposed method uses a simplified belief propagation (BP) algorithm that is able to identify whether a transmitter is a legitimate primary user or an attacker. In a primary user emulation attack (PUEA) a transmitter impersonates a primary user (PU) in order to deceive secondary users (SU) into believing that a channel is occupied. As a result, secondary users must vacate the channel immediately. This paper presents a simplified belief propagation method as a defence strategy against primary user emulation attacks. In our method each secondary user examines an incoming signal from a transmitter and determines with a certain probability whether the transmitter is a legitimate user or not. This probability is known as the belief. The beliefs at each secondary user are reconciled and a final belief is compared to a predefined threshold. If the final belief is below the threshold, the user is identified as an attacker. If it is above the threshold, the user is deemed a primary user. This result is then propagated throughout the network so that all users on the network are aware of the attacker. In this paper, we present a method based on the belief propagation framework. The proposed method converges in a single iteration; this is the result of a redefined messaging protocol and a simplified belief equation. As a result, the computational complexity of the method is reduced significantly, while still maintaining a high level of accuracy.