Constellation design for color space-based modulation in visible light communications

摘要

In this paper, we present a new strategy to design the constellation symbols in a visible light communication (VLC) system by considering multiple LED transmitters at different wavelengths. For this purpose, the LED transmitters are modeled as fixed points in a color space, and the constellation symbols are obtained by convex combinations of these points. In our formulation, the resulting constellation symbols have to reproduce on average a desired white tonality. Hence, the constellation design strategy is defined as a constrained optimization problem that seeks to maximize the minimum distance among the resulting symbols, but at the same time, to yield a desired white tonality on average. For evaluation purposes, we consider the CIE 1931 color space with 3 and 5 LED transmitters, and constellations with 4, 8 and 16 symbols. Our proposed methodology is compared with a previous work in the state of the art, where an important improvement is achieved with respect to the resulting Euclidean distance among constellation symbols. (C) 2018 Elsevier B.V. All rights reserved.