On the Achievable Max-Min User Rates in Multi-Carrier Centralized NOMA-VLC Networks

TL;DR

This paper investigates the maximum minimum user rates in multi-carrier VLC networks using NOMA, optimizing user pairing, subcarrier, and power allocation to enhance fairness and spectral efficiency.

Contribution

It introduces a low-complexity joint optimization approach for resource allocation in NOMA-VLC networks, combining user pairing, subcarrier, and power allocation strategies.

Findings

Quantifies achievable max-min user rates under various NOMA schemes.

Demonstrates the effectiveness of the D-NLUPA user pairing algorithm.

Provides insights into the performance and design of multi-user VLC networks.

Abstract

Visible light communications (VLC) is gaining interest as one of the enablers of short-distance, high-data-rate applications, in future beyond 5G networks. Moreover, non-orthogonal multiple-access (NOMA)-enabled schemes have recently emerged as a promising multiple-access scheme for these networks that would allow realization of the target spectral efficiency and user fairness requirements. The integration of NOMA in the widely adopted orthogonal frequency-division multiplexing (OFDM)-based VLC networks would require an optimal resource allocation for the pair or the cluster of users sharing the same subcarrier(s). In this paper, the max-min rate of a multi-cell indoor centralized VLC network is maximized through optimizing user pairing, subcarrier allocation, and power allocation. The joint complex optimization problem is tackled using a low-complexity solution. At first, the user pairing is assumed to follow the divide-and-next-largest-difference user-pairing algorithm (D-NLUPA) that can ensure fairness among the different clusters. Then, subcarrier allocation and power allocation are solved iteratively through both the Simulated Annealing (SA) meta-heuristic algorithm and the bisection method. The obtained results quantify the achievable max-min user rates for the different relevant variants of NOMA-enabled schemes and shed new light on both the performance and design of multi-user multi-carrier NOMA-enabled centralized VLC networks.