Impact of Hardware Impairments on the Outage Probability and Ergodic Capacity of One-Way and Two-Way Full-Duplex Relaying Systems

Hardware impairments (HI) always exist in wireless devices, especially the low-cost ones. However, due to the complicated mathematical analysis, previous studies on wireless networks usually neglected the HI, particularly for full-duplex relaying (FDR) systems. In this paper, we consider the impact of the HI on the outage probabilities (OPs) and ergodic capacities (ECs) of both one-way (OW) and two-way (TW) amplify-and-forward (AF) FDR systems. We also take into account the residual self-interference (RSI) due to the imperfect self-interference cancellation (SIC), which appears at the FDR node of the considered HI-OW-AF-FDR system and all nodes of the considered HI-TW-AF-FDR system. Particularly, we derive the exact expressions of the outage probabilities and ergodic capacities for the HI-OW-AF-FDR and HI-TW-AF-FDR systems using mathematical analysis. Numerical results show that the OPs and ECs of the two systems are significantly affected by both HI and RSI, however the impact of the HI is more serious. It is recommended that besides SIC techniques, effective methods to reduce the HI should also be used to guarantee the system performance.