Optimal Energy-Efficient Relay Deployment for Two-Way Relay System with Non-Ideal Power Amplifier

Realistic power amplifier (PA) model plays a very important role in the energy efficiency analysis for relay system, since it takes up to 70% of the total power consumption. In this paper, we aim to investigate the impact of non-ideal PA on the optimal relay deployment for two-way relay system using amplify forward or decode forward protocol in comparison with that of ideal PA. In the two-way relay system, physical-layer network coding (PNC) is used to assist the relay communication. Taking both the realistic non-ideal PA and ideal PA into consideration, the closed-form expressions for the optimal energy-efficient relay deployment are derived. Relative numerical simulation results show that the impact of non-ideal PA on the optimal relay deployment is that it requires the relay node to be deployed nearer to base station (BS) than that with the ideal PA. Furthermore, the energy efficiency of the two-way relay system with non-ideal PA could be largely improved by applying the optimal relay deployment.