Impacts of Nonlinear Energy Harvesting and Residual Self-Interference on the Performance of Full-Duplex Decode-and-Forward Relay System

In this paper, we investigate the usage of a nonlinear energy harvester at a full-duplex (FD) relay, which can harvest the energy from radio frequency (RF) signals transmitted from the source. We mathematically derive the exact closed-form expressions of outage probability (OP), throughput, and average symbol error rate (ASER) of the nonlinear energy harvester-wireless information and power transfer-FD relaying (N-WIPT-FDR) system over Rayleigh fading channels. Unlike linear energy harvester, nonlinear energy harvester results in more computational complexity. Furthermore, it makes the outage floor happen faster even when self-interference cancellation (SIC) techniques are effectively applied due to the saturation power threshold of the nonlinear energy harvester. The combination of nonlinear energy harvester characteristic and residual self-interference (RSI) has significant impacts on the OP, throughput, and ASER of the considered N-WIPT-FDR system. On the other hand, there is an optimal energy harvesting (EH) time duration, which minimizes the OP. This optimal value depends on the transmission power of the source and the saturation power threshold of the nonlinear energy harvester. Monte-Carlo simulations are conducted to validate the derived mathematical expressions.