NOMA for Multiple Access Channel and Broadcast Channel in Indoor VLC

TL;DR

This paper introduces a generalized non-OFDM NOMA scheme for indoor VLC that improves spectral efficiency and decoding performance in multiple access and broadcast channels, addressing limitations of traditional OFDM-based NOMA.

Contribution

It proposes a novel non-OFDM NOMA scheme for indoor VLC, demonstrating improved BER performance and computational efficiency over existing methods.

Findings

JML decoding outperforms traditional methods in MAC

Proposed scheme achieves lower BER in MAC scenarios

Efficient decoding with trade-offs in BER for BC

Abstract

Orthogonal frequency division multiplexing (OFDM) based non-orthogonal multiple access (NOMA) has increased complexity and reduced spectral efficiency in visible light communications (VLC) NOMA compared to radiofrequency NOMA due to non-negative real value constraints on transmit symbols. To address this issue, we propose a generalized non-OFDM based scheme for two scenarios of indoor VLC; i) Multiple access channel (MAC), ii) Broadcast channel (BC). We evaluate the performance of the proposed scheme for MAC using successive interference cancellation (SIC) based decoding, joint maximum likelihood (JML) decoding, and a combination of SIC and JML decoding. For BC, we evaluate the performance using SIC based decoding. It is observed that, for MAC, the proposed scheme with JML decoding performs better than the state-of-the-art orthogonal multiple access both in terms of bit error rate (BER) and computations. For BC, the proposed scheme is computationally efficient with trade-off on BER.