Secrecy Capacity and Optimal Power Allocation Scheme for Two-Way Untrusted Relay Networks

摘要

At present, there is little research on the performance of two-way untrusted relay in fading channel for two-way untrusted relay networks without direct link. This paper investigates the relationship between power allocation factor, friendly jammer's power factor and secrecy capacity of the system with external friendly jammer, and gives optimal power allocation scheme. Moreover, the ESC is calculated when the relay can conduct multi-user decoding, and the closed-form expression for the lower bound of ESC is derived. Simulation results show that the traditional two-way relay can improve the total secrecy capacity of the system. However, when the two-way untrusted relay can conduct multi-user decoding, the secrecy performance is inferior to one-way cooperative jamming system, and external friendly jammer can improve secrecy performance very well.