Rate-Splitting Multiple Access: A New Frontier for the PHY Layer of 6G

TL;DR

This paper explores Rate-Splitting Multiple Access (RSMA), a flexible transmission strategy for 6G wireless networks that balances interference decoding and noise treatment to improve efficiency, robustness, and complexity.

Contribution

It introduces RSMA as a novel, general framework that bridges existing multiple access strategies, offering enhanced spectral efficiency and robustness for 6G networks.

Findings

RSMA enables partial interference decoding and noise treatment.

RSMA improves spectral and energy efficiency in 6G scenarios.

RSMA offers robustness to imperfect channel information.

Abstract

In order to efficiently cope with the high throughput, reliability, heterogeneity of Quality-of-Service (QoS), and massive connectivity requirements of future 6G multi-antenna wireless networks, multiple access and multiuser communication system design need to depart from conventional interference management strategies, namely fully treat interference as noise (as commonly used in 4G/5G, MU-MIMO, CoMP, Massive MIMO, millimetre wave MIMO) and fully decode interference (as in Non-Orthogonal Multiple Access, NOMA). This paper is dedicated to the theory and applications of a more general and powerful transmission framework based on Rate-Splitting Multiple Access (RSMA) that splits messages into common and private parts and enables to partially decode interference and treat remaining part of the interference as noise. This enables RSMA to softly bridge and therefore reconcile the two extreme strategies of fully decode interference and treat interference as noise and provide room for spectral efficiency, energy efficiency and QoS enhancements, robustness to imperfect Channel State Information at the Transmitter (CSIT), and complexity reduction. We give an overview of RSMA and its potential to address the requirements of 6G. This paper provides an overview of RSMA and its potential to address the requirements of 6G.