Leveraging RIS in Consumer-Centric 6G Networks: Efficient Resource Allocation in RSMA-Based SWIPT Systems Under Hardware Impairments

This manuscript proposes an efficient resource management strategy for a rate-splitting multiple access (RSMA) based simultaneous wireless information and power transfer (SWIPT) system by leveraging reconfigurable intelligent surface (RIS) in consumer-centric sixth-generation (6G) networks for industry 5.0, under residual hardware impairments (RHIs) both at the transmitter and receiver nodes. Specifically, we aim to maximize the sum-rate of a RIS-assisted RSMA-based SWIPT system by incorporating a practical non-linear energy-harvesting model, while adhering to the quality-of-service (QoS), power-budget, power-splitting ratios, energy-conservation, and energy-harvesting constraints of the system. Moreover, the presented optimization technique addresses the highly non-convex problem in four distinct steps. Firstly, the power-allocation for both common and private messages of RSMA users is determined by converting a significantly non-convex power-allocation problem into a convex one by exploiting the successive-convex approximation (SCA) technique. Secondly, power-splitting ratios for RSMA users are computed by using the interior-point method facilitated by the Mosek-enabled toolbox in CVX. Thirdly, it computes transmit passive beamforming of a transmitter equipped with a transmissive-RIS (T-RIS), by exploiting SCA and semidefinite relaxation (SDR) techniques. Finally, passive beamforming vectors for the transmission and reflection regions of a simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) node are determined by converting a non-convex problem into a standard SDP problem using SCA, SDR, and Gaussian randomization techniques. Additionally, numerical simulation results affirm the effectiveness of the proposed optimization strategy, indicating superior performance against benchmark techniques and fast convergence within a reasonable number of iterations.