Ergodic Secrecy Capacity of Untrusted Relay and Full Duplex Destination Systems with Cooperative Jamming

A transmission model is investigated by combining the untrusted amplify-and-forward relay with full-duplex destination. To improve the secrecy performance of the system, the full duplex destination based jamming (FD-DBJ) scheme is proposed. The traditional half duplex DBJ scheme and the amplify-and-forward relaying scheme are compared with the proposed one to analyze the system performance. Through the reasonable analysis, the approximate closed-form solutions are derived for three strategies in the Rayleigh fading channel. Analyses and simulation results show that, in the high SNR regime, the analytical curves match well with the simulation results, and the advantage of FD-DBJ is also revealed through the performance comparison of three strategies. The optimal power allocation factor is analyzed for the FD-DBJ transmission strategy.