[Paper Review] An Algorithm to Realize Rate-Splitting in Gaussian Multi-access Channel

Xiaomao Mao, Huifang Chen+1 more|arXiv (Cornell University)|Aug 12, 2016

Advanced Wireless Communication Techniques3 references3 citations

TL;DR

This paper proposes a practical algorithm to compute splitting coefficients and successive decoding orders for Rate-Splitting Multiple Access (RSMA) in Gaussian multi-access channels. By establishing a deterministic mapping between system parameters and target rate tuples, the algorithm enables efficient, low-complexity RSMA implementation without user synchronization, achieving any rate tuple within the capacity polymatroid.

ABSTRACT

Rate Splitting Multiple Access (RSMA) is a code division multi-access technique which can achieve any base in the multi-access capacity polymatroid without high coding complexity or synchronization among the transmitting users. In this paper, a practical algorithm is proposed to compute the splitting coefficients and the successive decoding order of virtual users in Gaussian RSMA transmission. Based on the proposed algorithm, a deterministic mapping is built between the system parameters and the objective rate tuple for RSMA. As a result, the application of the RSMA technique becomes possible in current communication systems.

Motivation & Objective

• To enable practical implementation of Rate-Splitting Multiple Access (RSMA) in Gaussian multi-access channels.
• To compute splitting coefficients and decoding order for virtual users in RSMA without requiring user synchronization.
• To establish a deterministic mapping between system parameters and target rate tuples.
• To achieve any rate tuple within the multi-access capacity polymatroid with low coding complexity.
• To make RSMA viable for current communication systems through algorithmic realization.

Proposed method

• The algorithm computes splitting coefficients for users based on channel state information and target rates.
• It determines the successive decoding order of virtual users to minimize error floors and maximize spectral efficiency.
• A systematic procedure maps system parameters (e.g., channel gains, power constraints) to desired rate tuples.
• The method ensures that the sum rate achieves the outer bound of the capacity region via rate splitting.
• It uses a greedy-like optimization to select decoding order that maximizes sum rate under power and interference constraints.
• The algorithm is designed to be computationally efficient and suitable for real-time implementation.

Experimental results

Research questions

• RQ1 How can splitting coefficients and decoding order be computed efficiently in RSMA for Gaussian multiple access channels?
• RQ2 What deterministic mapping ensures that any desired rate tuple within the capacity polymatroid is achievable?
• RQ3 Can RSMA be implemented with low complexity and without requiring user synchronization?
• RQ4 What algorithmic structure enables practical deployment of RSMA in current communication systems?
• RQ5 How does the proposed method achieve the capacity region of the Gaussian MAC under power constraints?

Key findings

• The algorithm enables the realization of any rate tuple within the multi-access capacity polymatroid using rate-splitting.
• A deterministic mapping is established between system parameters and target rate tuples, ensuring reliable rate allocation.
• The method achieves high spectral efficiency with low coding complexity, suitable for real-time systems.
• The algorithm operates without requiring strict user synchronization, enhancing practicality.
• The proposed approach supports flexible rate adaptation and robust performance under varying channel conditions.
• The algorithm ensures that the sum rate achieves the theoretical outer bound of the Gaussian MAC capacity region.