Coordinated Full-Duplex Cooperative Transmission With RSMA in Multi-Cell Networks

This letter investigates the downlink performance of Cooperative Rate-Splitting Multiple Access (C-RSMA) in a multi-cell wireless network employing Joint-Transmission Coordinated Multipoint (JT-CoMP). Each cell comprises a multi-antenna base station (BS), multiple cell-center users (CCUs), and multiple cell-edge users (CEUs). Leveraging JT-CoMP, all BSs jointly transmit data to both CCUs and CEUs. To enhance signal quality at the cell edges, CCUs assist by relaying the common stream to CEUs via full-duplex (FD) decode-and-forward relaying. We aim to jointly optimize the beamforming vectors at the BSs, the allocation of common stream rates, and the transmit power at relaying users, i.e., CCUs, aiming to maximize the minimum achievable data rate. To address the non-convex challenge, we employ change-of-variables, first-order Taylor approximations, and a low-complexity algorithm based on Successive Convex Approximation (SCA). In this context, we also evaluate our proposed system model considering imperfect channel state information (CSI) and imperfect successive interference cancellation (SIC). The results show that the proposed FD C-RSMA can achieve 25% over FD C-NOMA with BS transmit power of 20 dBm.