Power Allocation for High Mobility OTFS-RSMA System With Path-Selective One-Tap Receiver

The utilization of orthogonal time frequency space (OTFS) modulation in multi-user systems offers a promising opportunity to enhance spectral efficiency in high-mobility channels. To improve spectral utilization of OTFS multiple access, we propose a novel transmission scheme that integrates OTFS with rate-splitting multiple access (RSMA). Specifically, we develop a power allocation strategy for the proposed OTFS-RSMA system by adopting a path-selective one-tap delay-time domain equalizer (DTE) at the receiver. We apply the successive convex approximation (SCA) algorithm to solve the formulated non-convex average sum rate maximization problem. Finally, we compare the average sum rate results of the proposed OTFS-RSMA scheme with the OTFS-non-orthogonal multiple access (NOMA), and orthogonal frequency division multiplexing (OFDM) related benchmarks under the high mobility scenarios.