Performance Insights on IEEE 802.11a/g Compliant Software-based In-Band Full Duplex Relay Systems

Over the last decade, infrastructure relays have been employed by wireless standards, such as WiMAX and LTE, for coverage and performance enhancement. However, due to their Half-Duplex (HD) nature, these relays incur spectral losses and increase the end-to-end delay. In contrast, in-band Full-Duplex (FD) relays can effectively cope with these issues through simultaneous reception and forwarding, provided that the looped-back Self-Interference (SI) is sufficiently suppressed. Driven by the possible performance gain of FD relaying over traditional HD relay systems; in this work, we present the first implementation of IEEE 802.11a/g compliant FD relay system in GNU Radio framework. Given the Open Source nature of this real-time signal processing software, the implementation is completely transparent and can be studied in all details and modified if needed. For a holistic evaluation of our relay system, we implemented both Amplify and Forward (AF) and Decode and Forward (DF), the two widely adopted relaying strategies. We assess the performance of these relaying strategies both analytically and in simulation experiments. Our results demonstrate and underline the potential gains of full-duplex relays in-terms of spectral efficiency and end-to-end physical layer latency over traditional half-duplex relay systems.