Otimização Redes de Comunicações Sem Fio com RSMA e STAR-RIS

This article considers a wireless communication system assisted by a Simultaneous Transmission and Reflection Reconfigurable Intelligent Surface (STAR-RIS) considering the Rate Division Multiple Access technique (RSMA). STAR-RIS is a novel technology that, unlike traditional RIS, is capable of not only reflecting but also transmitting the incident signal. However, due to the large number of elements at the STAR-RIS, the accurate acquisition of Channel State Information (CSI) requires considerable training overhead, which is limiting in practical scenarios. Therefore, in this work, a novel solution based on the Particle Swarm Optimization (PSO) technique is proposed to maximize the achievable sum-rate of the system by jointly optimizing the rate allocation vector, the beamforming vector at the BS, and the transmission and reflection coefficients of the STAR-RIS without any knowledge of the CSI. The results show that the proposed solution outperforms orthogonal (OMA) and non-orthogonal (NOMA) multiple access techniques assisted by STAR-RIS.