Performance Analysis of Two Color-Coded 8D Modulation Formats in FBMC-VLC System

In this letter, two innovative color-coded eight-dimensional (8D) modulation formats (namely 8D-plane and 8D-stereo) are proposed and experimentally validated in a filter bank multi-carrier based visible light communication (FBMC-VLC) system. The 8D-plane format is formed by combining geometric shell structures in a plane space. In contrast, 8D-stereo format is constructed by combining 3D constellations in a stereoscopic space, which further reduces the design complexity of high-dimensional constellations. Both formats utilize color coding to achieve joint modulation across different dimensions. Symbols with distinct states of polarization are utilized across various dimensions to maximize the minimum Euclidean distance and alleviate nonlinear interference. Experimental results show that in terms of peak-to-peak voltage and bias current, 8D-stereo-FBMC exhibits the broadest operational range compared with 2D-FBMC, 4D-FBMC, and 8D-plane-FBMC. When the BER meets <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.8\times 10^{-3}$ </tex-math></inline-formula>, the proposed 8D-stereo-FBMC scheme has a 0.4 Gbit/s increase in data rate compared to 8D-plane-FBMC, which indicates the remarkable tolerance to nonlinearity.