Multi-User Relay Selection for Full-Duplex Radio

• Published in: IEEE transactions on communications Vol. 67; no. 2; pp. 955 - 972
• Main Authors: Atapattu, Saman, Dharmawansa, Prathapasinghe, Di Renzo, Marco, Tellambura, Chintha, Evans, Jamie S.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.02.2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); Institute of Electrical and Electronics Engineers
• Subjects: Coherence; Computer Science; Computer simulation; Full-duplex communications; Information Theory; Interference; Interference cancellation; Links; multiple-user networks; outage probability; Power system reliability; Probability; Relay networks; Relay networks (telecommunications); relay selection; residual self-interference; Signal to noise ratio; throughput; residual self- interference; multiple-user networks; outage probability; Full-duplex communications; throughput; relay selection
• ISSN: 0090-6778; 1558-0857
• DOI: 10.1109/TCOMM.2018.2877393

This paper investigates a user-fairness relay selection (RS) problem for decode-and-forward (DF) full-duplex (FD) relay networks, where multiple users cooperate with multiple relays in each coherence time. We consider two residual self-interference (RSI) models with or without direct links. We propose a sub-optimal relay selection (SRS) scheme which requires only the instantaneous channel state information (CSI) of source-to-relay and relay-to-destination links. To evaluate the performance, the outage probability of SRS is derived for different scenarios depending on RSI models and the availability of direct links. To further investigate, asymptotic expressions are derived for the high-transmit power regime. For comparison purposes, 1) the average throughputs of the FD and half-duplex (HD) modes are derived; 2) non-orthogonal transmission is considered and its performance is discussed with approximations; and 3) the impact of imperfect CSI is investigated with the aid of analysis. While simulation results are provided to verify the analytical results, they reveal interesting fundamental trends. It turns out that a significant throughput degradation occurs with FD mode over HD mode when self-interference is fully proportional to the transmit power. Since all users can communicate in the same coherence time with the FD mode, these joint RS schemes are useful for user-fairness low-latency applications.