Position Design for Reconfigurable Intelligent-Surface-Aided Indoor Visible Light Communication Systems

Abstract

As an emerging technology, reconfigurable intelligent surfaces (RISs) have been investigated to apply to visible light communication (VLC) systems to enhance the transmission capability of the systems, recently. However, the optimization of RIS location in VLC has not been studied. In this study, we first investigated RIS positioning design in VLC. Specifically, we set two indoor VLC scenarios with a VLC RIS composed of a mirror array. We set the achievable rates in different scenarios as the utility functions to optimize the position of the RIS array according to the placement of the access point (AP) and user. We found that the problems are nondeterministic polynomial (NP)-hard. Aiming at the different optimization problems, the particle swarm optimization (PSO) algorithm was used to confirm the optimal position of the RIS array. Unlike the traditional algorithm, we added an adaptive mutation mechanism to the algorithm to guarantee the randomness of the particle to search for the optimal solution. Finally, our simulation results showed that the proper position design of the RIS array can improve the communication performance to a greater degree, while the computational complexity required to solve the position optimization problems through the PSO algorithm can be significantly reduced compared with that required for the exhaustive search method in the case where both of the algorithms find the optimal solution.

Artificial Intelligence in Visible Light Positioning for Indoor IoT: A Methodological Review

“…An ANN used the estimation of the PSO combined with the RSS data to refine the estimation and accurately predict the real-time location of the receiver, with a mean 3D positioning error of 10cm, while offering 3 times wider coverage. In [114] PSO is studied to determine the optimal position of an RIS array to maximize the achievable rate performance, based on PD sensors.…”

Sum Rate and Fairness Optimization in RIS-Assisted VLC Systems

“…Also, in [11], the maximization of the achievable network throughput under the point source assumption for the NLOS channel model was investigated using greedy policy algorithm, while [12] studied the maximization of the spectral efficiency of time-division-multiple-access (TDMA) system under the same assumption using alternating optimization and frozen-variable algorithm. The works in [13] and [14] investigated maximizing the achievable throughput using particle swarm optimization (PSO), where [13] optimized the position of the RIS elements and [14] optimized the assignment of the elements in multiple-input multiple-output (MIMO) setup. In addition, [15] proposed a hybrid NOMA scheme for improving the RIS-assisted VLC system capacity, while [16] studied improving the asymptotic capacity of the multiple-input single-output (MISO) RIS-aided VLC systems by utilizing the theory of quadratic programming.…”

A trial combing a mirror array-based RIS with a liquid crystal-based RIS in indoor visible light communications

“…Meanwhile, in current research, VLC RIS composed of a mirror array is more attractive than a meta-surface-based VLC RIS since a mirror array-based VLC RIS costs lower and is controlled more precisely than the latter. The current research on a mirror array-based VLC RIS is mainly about increasing the communication performance in single-input single-output VLC [3,4], asymptotic capacity in multiple-input single-output VLC [5], and other performance indexes in multiple-input multiple-output VLC [6,7]. With the development of the meta-materials, liquid crystal (LC) RIS is investigated to be able to steer the incident signal and amply the light signal.…”