Joint Hybrid Precoding and Rate Allocation for RSMA in Near-Field and Far-Field Massive MIMO Communications

In this letter, we propose to apply rate-splitting multiple access (RSMA) to improve the system’s spectral efficiency (SE) and manage the severe multi-user interference in the mixed near- and far-field communication system. Specifically, RSMA is utilized to serve all near-field and far-field users on the same time-frequency resource. To further explore the potential of RSMA, we consider the user selection to design the optimal rate-splitting strategy. To this end, we formulate an optimization problem to maximize the sum SE via the joint consideration of user selection, hybrid precoding, and rate allocation. For tackling this non-convex problem, we propose an alternative optimization algorithm based on successive convex approximation and simulated annealing methods. Simulation results reveal that our proposed algorithm achieves a larger performance gain than the other competing benchmark schemes in terms of SE improvement.