Zero SIC Based Rate Splitting Multiple Access Technique

In rate splitting multiple access (RSMA), all users first decode a common-stream (CS) by treating all private-streams (PS) as interference. After that, successive interference cancellation (SIC) is performed to remove the CS, and each user will then decode its PS by treating other users’ PS as interference. Although RSMA achieves a better management of interference compared to non-orthogonal multiple access (NOMA), it still has partial interference while decoding CS and requires perfect SIC for decoding PS. In addition, with increasing users, the interference level and SIC interactions also increase. To overcome these issues, this letter proposes a novel quadrature-RSMA (Q-RSMA) technique that removes the requirement of SIC to decode PS. In addition, Q-RSMA offers interference-free detection of CS. This work determines the closed-formed optimal solution of the formulated non-convex optimization problem to maximize the sum-rate of Q-RSMA. Moreover, the proposed Q-RSMA is compared with RSMA, NOMA, quadrature-NOMA techniques. Comparisons show that Q-RSMA reduces decoding latency, provides better interference-management, and is more spectral and energy-efficient than other techniques.