Impact of the relay on the coverage region of multiple‐access channels
Ehsan Moeen Taghavi, Ghosheh Abed Hodtani · IET Communications · 2016
From practical and theoretical viewpoints, performance analysis of communication systems by using information‐theoretic results is important. In this study, first, the authors obtain a general achievable rate region for three‐user discrete memoryless multiple‐access relay channel (MARC) via partial decode and forward strategy and regular block Markov encoding/backward decoding. Also by extending the discrete alphabet results to the continuous alphabet channel, an inner bound for three‐user Gaussian MARC (GMARC) is achieved. Next, based on the inner bound of three‐user GMARC, they analyse the impact of a relay on the coverage region of MARC, as a basic model for uplink communications between a base station and users with the help of a relay. This analysis includes the coverage region for the multiple‐access channel and two‐user GMARC as special cases. Considering rate regions for the GMARC and fading GMARC, it is proved that in a fixed transmission rate, the relay extends coverage region of the MARC. Numerical illustrations confirm their theoretical results.