Performance Evaluation of Down Link Rate Splitting Multiple Access for MIMO System in Massive Machine Type Communication

Abstract

The advent of advanced cellular technologies, such as 5G and beyond, has enabled the realization of a converged network supporting various use cases. Among these, massive Machine Type Communication (mMTC) has emerged as a prominent application, facilitating communication between a massive number of devices within a single network. To address the challenges posed by mMTC, recent advancements have introduced Non Orthogonal Multiple Access (NOMA) and Rate Splitting Multiple Access (RSMA) techniques. Recently RSMA has shown a promising improvement in rate and Degree of Freedom (DoF) analysis. However its application and performance in the context of downlink mMTC, particularly in a Multiple-Input Multiple-Output (MIMO) setting remain unexplored. Motivated by the need to enhance mMTC support while maintaining low power usage this thesis project focuses on the performance evaluation of RSMA and its extension Power Partitioning Rate Splitting Multiple Access (PP-RSMA) in a MIMO system for mMTC services. The analysis primarily revolves around two key aspects: rate and DoF analysis. The study investigates the performance characteristics of the Broadcast Channel (BC)RSMA system in terms of DoF and compares RSMA with NOMA and other related multipleaccess (MA) techniques in terms of DoF and achievable sum rate. Using MATLAB software, extensive simulations were conducted to assess the performance of the proposed PP-RSMA technique. The results demonstrated that RSMA outperformed other MA techniques in terms of rate, exhibiting a significant increase of 22.9% to 11.64% compared to Space Division Multiple Access (SDMA) and 20.2% to 15% compared to NOMA across different MTC deployments, particularly under low Channel State Information at the Transmitter (CSIT) quality. Additionally, RSMA enhanced the DoF performance of the system by 20.2% to 22.1% compared to SDMA and 22.94% to 11.64% compared to NOMA when low CSIT quality is available for MTC devices. Moreover, in scenarios where MTC devices have low or no CSIT information, PP-RSMA effectively handled the heterogeneity in demand and CSIT requirements of MTC devices, exhibiting superior performance. Link Level Simulations (LLS) demonstrated that the throughput achieved by the system aligned closely with the rate capacity, reinforcing the efficacy of PP-RSMA in mMTC MIMO systems.