LAUSR

Reconfigurable intelligent surface-assisted time reversal multiple access (RIS-TRMA) is proposed to overcome the limitations of existing RIS and TR techniques in wireless communication systems. Traditional RIS deployments often suffer from complex channel estimation, particularly with a large number of RIS elements, while TR typically requires a rich multipath environment with more paths than users. To address these challenges, the proposed RIS-TRMA leverages the concept of RIS phase shifter-based virtual multipath (VMP) channels. The VMP is utilized to enhance the TR effect where the number of multipath (i.e. the number of RIS elements) exceeds the number of non-orthogonal multiple access (NOMA) users. The performance of the proposed RIS-TRMA is analyzed in terms of capacity, outage probability (OP), spectral efficiency (SE), and complexity compared to RIS-NOMA.