Designing A Dimmable OPPM-Based VLC System Under Channel Constraints

TL;DR

This paper presents a dimming-compatible VLC system using OPPM in office environments, optimizing parameters for channel constraints, and applying TCM for improved coding gain.

Contribution

It introduces a novel approach combining OPPM with TCM for dimming control in VLC systems considering channel constraints and dispersive effects.

Findings

Optimal code length varies with dimming levels.

Trellis coded modulation improves coding gain up to 3 dB.

System adheres to illumination standards in office settings.

Abstract

In this paper, we design a dimming compatible visible light communication (VLC) system in a standard office room according to illumination standards under channel constraints. We use overlapping pulse position modulation (OPPM) to support dimming control by changing the code weights. The system parameters such as a valid interval for dimming together with an upper bound for bit rate according to the channel delay spread are investigated. Moreover, considering the dispersive VLC channel and using Monte Carlo (MC) simulations, a method is proposed to determine the minimum code length in different dimming levels in order to achieve a valid bit error rate (BER). Finally, trellis coded modulation (TCM) is suggested to be applied to OPPM in order to take advantage of consequent coding gain which could be up to $3$ dB.