User Association in User-Centric Hybrid VLC/RF Cell-Free Massive MIMO Systems

TL;DR

This paper proposes a hybrid VLC/RF cell-free massive MIMO system with novel user association algorithms, demonstrating significant improvements in sum-rate over random associations and standalone networks.

Contribution

It introduces a hybrid VLC/RF cell-free MIMO system with new user association and clustering algorithms, enhancing system performance.

Findings

Proposed algorithms outperform random user association in sum-rate.

Hybrid system shows potential advantages over standalone VLC or RF networks.

Simulation results confirm improved system performance with the new methods.

Abstract

A continuous goal in all communication systems is to enhance the users experience and provide them with the highest possible data rates. Recently, the concept of cell-free massive MIMO (CF-mMIMO) systems has been considered to enhance the performance of systems that operate merely with Radio Frequency (RF) or visible light communication (VLC) technologies. In this paper, a hybrid VLC/RF cell-free massive MIMO system is proposed where an RF cell-free network and a VLC cell-free network coexist to serve users. The idea is to utilize the benefits of each network and balance the load aiming at maximizing the system's sum-rate. The system is evaluated using zero-forcing (ZF) precoding scheme. Two user association algorithms are proposed to assign users to either the VLC or the RF networks. In addition, two user-centric clustering approaches are proposed and evaluated. Simulation results show that the proposed association algorithms significantly outperform a random network association of users in terms of sum-rate. Results also show great potential for the proposed system compared to standalone cell-free networks.