Extending the Capacity Region with Distributed Uplink Rate Splitting Multiple Access (DU-RSMA)

One of the main goals of the upcoming sixthgeneration (6G) wireless networks is the ability to support higher network density, while ensuring a high quality of service for each user. To this end, we introduce distributed uplink ratesplitting multiple access (DU-RSMA), define its basic principles, and provide insights into its benefits. DU-RSMA allows multiple users to efficiently share the same resource block through message splitting and the use of remote radio heads that independently decode incoming messages and exchange the decoded information through a 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 through a novel metric, termed as “fill factor”. Since adaptive transmission rates are considered, the performance of the proposed scheme is investigated in terms of the ergodic rate of both users, for which we derive closed-form expressions. Simulation results illustrate the performance gains of DU-RSMA over corresponding benchmarks and investigate the effect of system parameters on its performance.