General and new inner bound for multiple-access relay channel and two certain capacity theorems

In this study, the authors obtain a general and new achievable rate region and some certain capacity theorems for multiple-access relay channel (MARC), using partial decode-and-forward (PDF) strategy at the relay, superposition coding at the transmitters and multiple-access and relay channel (RC) decoding schemes. (a) The authors general rate region (i) generalises the achievability part of Slepian-Wolf multiple-access capacity theorem to the MARC, (ii) extends the Cover-El Gamal best achievable rate for the RC with PDF strategy to the MARC, (iii) gives the Kramer-Wijengaarden anticipated rate region for the MARC and (iv) meets max-flow min-cut outer bound for some important classes of the MARC. (b) They extend the results to the Gaussian case as an important practical aspect of MARC and obtain (v) a general and new achievable rate region for Gaussian Slepian-Wolf MARC. Finally, they evaluate their inner bounds for Gaussian MARC numerically, and illustrate specifically that when the relay is closer to the transmitters, their rates are greater than the previous corresponding rates.