Radio resource allocation to provide physical layer security in relay-assisted cognitive radio networks

In this study, the authors consider a cooperative communication framework based on one-way and two-way relays to provide secure communications for secondary users (SUs) within an orthogonal frequency-division multiple access-based underlay cognitive network. By proposing a radio resource allocation problem with the aim of maximising the secrecy sum-rate of SUs and solving it, they show that the deployment of relays is vital to achieve a non-zero secrecy sum-rate. Also, the impact of two-way relay in system performance improvement is clearly visible in comparison with one-way relay such that it can roughly double the resulting system secrecy sum-rate. The impact of different system parameters on the achievable secrecy sum-rate for both one-way and two-way relays is also investigated and compared through simulations.