Rate-Splitting Approach for Downlink Multiuser Relay Systems

This paper studies a downlink multiuser relay system. Especially, multi user is dropped inside the building, and relay MT antenna and RU antenna is deployed at the rooftop and the ceiling of indoor office, respectively. We formulate problem based on Rate-Splitting Multiple Access (RSMA) to achieve max-min fairness (MMF) amongst multiuser. In RSMA scheme, each user's desired message is split into a common part and a private part and the symbol streams are linearly precoded and transmitted. These process enable a flexible non-orthogonal transmission and to design beam that is robust to interference. In this paper, we use weighted minimum mean-square error (WMMSE) approach to solve MMF problem in relay system. The Simulation results show superiority of RSMA for multiuser relay system compared with conventional scheme.