Rate-splitting multiple access: SIC-free implementation, codeword segmentation, and mismatched decoding
File(s)
Author(s)
Zhang, Sibo
Type
Thesis or dissertation
Abstract
Multiple access techniques have played a pivotal role in advancing wireless communications. Rate-splitting multiple access (RSMA) has been recognized as a promising multiple access technique for future wireless systems. However, practical implementation challenges may restrict its applicability. This thesis addresses such challenges by proposing novel extensions of RSMA with lower implementation complexity and by investigating the performance of different RSMA schemes under practical constraints.
First, we develop alternative receiver designs for RSMA beyond the conventional hard successive interference cancellation (SIC). These designs can be broadly classified into two categories: SIC-based and SIC-free. Using metrics derived from mutual information, we model both categories and evaluate their theoretical limits. Our analysis and link-level simulations demonstrate that RSMA can retain its performance advantages even without SIC at the receiver. Second, we introduce a new RSMA architecture, termed codeword-segmentation RSMA (CS-RSMA). This approach reduces the complexity of encoding/decoding, control signaling, and retransmission, while achieving performance comparable to or better than existing RSMA schemes. These contributions open the door to practical and competitive RSMA strategies for 6G and beyond.
In addition to RSMA, this thesis also investigates the broader challenge of interference in wireless communications. By applying mismatched decoding, we analyze scenarios where interference is treated suboptimally, providing new insights into its impact, proposing novel receiver designs, and introducing a refined framework for performance evaluation that more accurately captures interference effects.
First, we develop alternative receiver designs for RSMA beyond the conventional hard successive interference cancellation (SIC). These designs can be broadly classified into two categories: SIC-based and SIC-free. Using metrics derived from mutual information, we model both categories and evaluate their theoretical limits. Our analysis and link-level simulations demonstrate that RSMA can retain its performance advantages even without SIC at the receiver. Second, we introduce a new RSMA architecture, termed codeword-segmentation RSMA (CS-RSMA). This approach reduces the complexity of encoding/decoding, control signaling, and retransmission, while achieving performance comparable to or better than existing RSMA schemes. These contributions open the door to practical and competitive RSMA strategies for 6G and beyond.
In addition to RSMA, this thesis also investigates the broader challenge of interference in wireless communications. By applying mismatched decoding, we analyze scenarios where interference is treated suboptimally, providing new insights into its impact, proposing novel receiver designs, and introducing a refined framework for performance evaluation that more accurately captures interference effects.
Date Issued
2025-11-07
Date Awarded
2026-02-01
Copyright Statement
Attribution-NonCommercial 4.0 International Licence (CC BY-NC)
License URL
Advisor
Clerckx, Bruno
Sponsor
Engineering and Physical Sciences Research Council
Publisher Department
Department of Electrical and Electronic Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)