Uplink RSMA With Dual-Polarized Multi-User MIMO Over Correlated Rician Channels in Finite Blocklength Regime

Abstract

This paper introduces a successive interference cancellation (SIC)-free uplink rate-splitting multiple access (RSMA) framework with dual-polarized multiple-input and multiple-output (DP-MIMO) to overcome decoding complexity and error propagation. Different from traditional uplink RSMA, the BS manages inter-user and intra-user interference by exploiting the DP antenna architecture, which eliminates the requirement of SIC. To validate the efficacy of the proposed framework, we compare the finite-blocklength (FBL) achievable sum spectral efficiency (SE) of DP-MIMO without SIC (DP-noSIC), single-polarized MIMO without SIC (SP-noSIC) and SP-MIMO with a local-SIC strategy (SP-localSIC) over correlated Rician channels. Specifically, we first develop the minimum mean-square error (MMSE) channel estimator for correlated Rician DP-MIMO channels and obtain the channel estimates and the error covariance matrices. Then, with the instantaneous signal-to-interference-plus-noise ratio (SINR), the sum SE maximization problem is established for the three schemes under FBL constraints. To solve the formulated problem, a unified algorithm framework is developed for efficient combiner design and power control. Simulation results reveal the performance superiority of the proposed DP-noSIC scheme, which attains the highest sum SE compared to the SP-noSIC and SP-localSIC schemes under different system setups. The observed outcomes demonstrate the effectiveness and robustness of DP-noSIC in improving throughput and reducing complexity.