Power Domain Sparse Dimensional Constellation Multiple Access (PD-SDCMA): A Novel PD-NOMA for More Access Users

TL;DR

This paper introduces PD-SDCMA, a novel power-domain sparse constellation multiple access scheme for 6G networks, which reduces interference and supports more users by sparsely superposing low-dimensional constellations in high-dimensional spaces.

Contribution

It proposes a new PD-SDCMA scheme with a signal space dimension selection strategy that sparsely superposes constellations, improving user support and interference management in NOMA systems.

Findings

Outperforms traditional PD-NOMA in user capacity under AWGN channels.

Achieves better BER performance with QPSK and 16QAM modulations.

Supports more users with efficient spectrum utilization.

Abstract

With the advent of the 6G mobile communication network era, the existing non-orthogonal multiple-access (NOMA) technology faces the challenge of high successive interference in multi-user scenarios, which limits its ability to support more user access. To address this, this paper proposes a novel power-domain sparse-dimensional constellation multiple-access scheme (PD-SDCMA). Through the signal space dimension selection strategy (S2D-strategy), this scheme sparsely superposes low-dimensional constellations onto high-dimensional signal spaces, and reduces the high-order interference caused by SC by taking advantage of the non-correlation between dimensions. Specifically, PD-SDCMA reduces the successive interference between users by sparsifying the dimension allocation of constellation superposition and designs a sparse superposition method based on the theory of vector space signal representation. Simulation results show that, under the AWGN channel, PD-SDCMA significantly outperforms the traditional PD-NOMA in terms of the number of supported users under QPSK and 16QAM modulations, and also has better BER performance. This paper provides a new solution for efficient spectrum utilization in future scenarios with large-scale user access.