Security-oriented transmission based on cooperative relays in cognitive radio

In this paper, we propose a security-oriented transmission scheme with the help of multiple relays in Cognitive Radio (CR). To maximise the Secrecy Capacity (SC) of the source-destination link in CR, both beamforming and cooperative jamming technologies are used to improve the performance of the Secondary User (SU) and protect the Primary User (PU). The effectiveness of the proposed scheme is demonstrated using extensive simulation. Both theoretical analyses and simulation results reveal that the proposed scheme contributes to the secure transmission of the SU with acceptable attenuation of the Signal-to-Noise Ratio (SNR) at the PU receiver, and the upper bound of the SC at the SU receiver is able to exploit the power allocation strategy.