Distributed Uplink Rate Splitting Multiple Access (DU-RSMA): Principles and Performance Analysis

TL;DR

This paper introduces DU-RSMA, a novel uplink multiple access scheme for 6G networks that enhances capacity and performance through distributed rate splitting and feedback-enabled cooperation between remote radio heads.

Contribution

The paper proposes DU-RSMA, a new distributed uplink multiple access scheme with feedback, providing analytical performance metrics and demonstrating superior capacity and outage performance over existing schemes.

Findings

DU-RSMA increases the achievable capacity region.

The scheme outperforms benchmarks in simulations.

Closed-form expressions for ergodic rate and outage probability are derived.

Abstract

One of the main goals of the upcoming sixth-generation (6G) wireless networks is the ability to support higher network density, while ensuring a high quality of service for each user. In this paper, we introduce distributed uplink rate-splitting multiple access (DU-RSMA), define its basic principles, and provide insights into its advantages. Specifically, a system with two remote radio heads (RRHs) and two users is investigated. To improve the performance of the system, we consider that the RRHs can communicate through a feedback link, and thus they are able to decode the received messages either independently or with the assistance of the other RRH, since the decoded information can be shared through the feedback link. It should be noted that this scheme increases the achievable capacity region compared to the known multiple access schemes, which is also evaluated by a novel metric termed ``fill factor''. Both the case of adaptive transmission rates and the case of fixed transmission rates are investigated. To this end, the ergodic rate is investigated to cover the former case, while the outage probability is studied for the latter. Closed-form expressions are derived for both metrics. Finally, the analytical expressions are validated by simulation results, which explicitly show the impact of each parameter on the performance of the system, and prove that the proposed scheme outperforms the corresponding benchmarks.