Optimal soft combination for multiple antenna energy detection under primary user emulation attacks

One of common threats imposed to the cognitive radio (CR) network is primary user emulation attack (PUEA), where some malicious users try to mimic the primary signal and deceive secondary users to prevent them from accessing the vacant frequency. Here, we propose a cooperative spectrum sensing scheme based on energy detection for CR networks in the presence of multiple smart PUEAs with spectrum sensing capability. In particular, we assume that the CR receiver has a number of L antennas and the CR transmitter sends combined information to the fusion center using beamforming with a single antenna. Soft combination of the observed energies from different CR users is investigated. By employing the Neyman–Pearson criterion, an optimal soft combination scheme is designed to maximize the cognitive signal-to-interference-plus-noise ratio (CSINR) for a given false alarm probability. Comparative simulation results validate the superiority of our proposed method in terms of detection accuracy compared to conventional methods.