Joint Constellation-Labeling Optimization for VLC-CSK Systems

In this letter, we have optimized the joint constellation-labeling for a finite number of signals in visible light communication (VLC) systems with color-shift keying (CSK) modulation by maximizing the pragmatic mutual information (PMI). First, an equivalent parallel channel model of the VLC-CSK system is constructed. Then the PMI is derived to be the objective function of the newly formulated joint constellation-labeling optimization problem of the VLC-CSK system. Simulated annealing (SA) algorithm and modified interior point method (MIPM) are adopted to solve the joint constellation-labeling optimization problem. Simulation results show that the proposed methods improve the PMI performance compared to the existing constellation-labeling scheme of signals, especially in the low signal-to-noise ratio (SNR) region. Besides, it can been seen that the MIPM saves a large amount of computational time compared to the SA algorithm while achieving the same performance improvement.