DC-Informative Joint Color-Frequency Modulation for Visible Light Communications

TL;DR

This paper introduces a novel constellation design method for RGB LED-based visible light communication that leverages multiple diversity resources and high-dimensional sphere packing to improve error rates under practical constraints.

Contribution

It proposes the DC-informative joint color-frequency modulation (DCI-JCFM), a high-dimensional constellation design approach that jointly optimizes multiple optical and electrical resources for VLC.

Findings

Significant error rate improvements over decoupled schemes.

Effective under various illumination balance conditions.

Utilizes high-dimensional sphere packing for better constellation efficiency.

Abstract

In this paper, we consider the problem of constellation design for a visible light communication (VLC) system using red/green/blue light-emitting diodes (RGB LED), and propose a method termed DC-informative joint color-frequency modulation (DCI-JCFM). This method jointly utilizes available diversity resources including different optical wavelengths, multiple baseband subcarriers, and adaptive DC-bias. Constellation is designed in a high dimensional space, where the compact sphere packing advantage over lower dimensional counterparts is utilized. Taking into account multiple practical illumination constraints, a non-convex optimization problem is formulated, seeking the least error rate with a fixed spectral efficiency. The proposed scheme is compared with a decoupled scheme, where constellation is designed separately for each LED. Notable gains for DCI-JCFM are observed through simulations where balanced, unbalanced and very unbalanced color illuminations are considered.