Rate-Splitting Multiple Access for Overloaded Multi-group Multicast: A First Experimental Study

TL;DR

This paper experimentally evaluates Rate-Splitting Multiple Access (RSMA) for multi-group multicast, demonstrating its superior fairness and throughput over traditional methods in real-world line-of-sight wireless environments.

Contribution

First experimental study of RSMA-based multi-group multicast, comparing it with SDMA and NOMA, validating theoretical advantages in practical settings.

Findings

RSMA achieves higher fairness and throughput than SDMA and NOMA.

Experimental results confirm RSMA's theoretical benefits in real-world scenarios.

RSMA outperforms other schemes across various channel conditions.

Abstract

Multi-group multicast (MGM) is an increasingly important form of multi-user wireless communications with several potential applications, such as video streaming, federated learning, safety-critical vehicular communications, etc. Rate-Splitting Multiple Access (RSMA) is a powerful interference management technique that can, in principle, achieve higher data rates and greater fairness for all types of multi-user wireless communications, including MGM. This paper presents the first-ever experimental evaluation of RSMA-based MGM, as well as the first-ever three-way comparison of RSMA-based, Space Divison Multiple Access (SDMA)-based and Non-Orthogonal Multiple Access (NOMA)-based MGM. Using a measurement setup involving a two-antenna transmitter and two groups of two single-antenna users per group, we consider the problem of realizing throughput (max-min) fairness across groups for each of three multiple access schemes, over nine experimental cases in a line-of-sight environment capturing varying levels of pathloss difference and channel correlation across the groups. Over these cases, we observe that RSMA-based MGM achieves fairness at a higher throughput for each group than SDMA- and NOMA-based MGM. These findings validate RSMA-based MGM's promised gains from the theoretical literature.