Max-Min Fairness of Rate-Splitting Multiple Access with Finite Blocklength Communications

TL;DR

This paper explores the use of Rate-Splitting Multiple Access (RSMA) in low-latency wireless communications, demonstrating its ability to achieve fair data rates with shorter blocklengths compared to other methods, especially with cooperative transmission.

Contribution

It introduces an optimal design for time allocation and precoding in RSMA under finite blocklength constraints, analyzing its fairness and latency benefits in various network scenarios.

Findings

RSMA achieves similar fairness rates as NOMA and SDMA with shorter blocklengths.

Cooperative transmission enhances RSMA's performance in low-latency settings.

RSMA is a promising approach for user fairness in low-latency wireless networks.

Abstract

Rate-Splitting Multiple Access (RSMA) has emerged as a flexible and powerful framework for wireless networks. In this paper, we investigate the user fairness of downlink multi-antenna RSMA in short-packet communications with/without cooperative (user-relaying) transmission. We design optimal time allocation and linear precoders that maximize the Max-Min Fairness (MMF) rate with Finite Blocklength (FBL) constraints. The relation between the MMF rate and blocklength of RSMA, as well as the impact of cooperative transmission are investigated for a wide range of network loads. Numerical results demonstrate that RSMA can achieve the same MMF rate as Non-Orthogonal Multiple Access (NOMA) and Space Division Multiple Access (SDMA) with smaller blocklengths (and therefore lower latency), especially in cooperative transmission deployment. Hence, we conclude that RSMA is a promising multiple access for guaranteeing user fairness in low-latency communications.