Resource Allocation for RSMA-Based Symbiotic Radio Systems Under Imperfect SIC and CSI

Rate-splitting multiple access (RSMA) is a crucial technology of 6G to achieve non-orthogonal transmission and better interference optimization. In this paper, we focus on the resource allocation (RA) problem for a RSMA-based symbiotic radio system under imperfect successive interference cancellation and imperfect channel state information. A transmit power minimization problem is formulated by jointly optimizing the beamforming vector of the primary base station, reflection coefficients and common stream. To solve the non-convex problem, an iterative-based robust RA algorithm is proposed by using the alternating optimization method, successive convex approximation, and semi-definite relaxation. Simulation results demonstrate that the proposed algorithm can effectively decrease power consumption and improve the robustness by comparing it with the RA algorithms with traditional access methods.