Power efficient LED placement algorithm for indoor visible light communication

Influence factors on illuminance distribution uniformity and energy saving of the indoor illumination control method

This study investigated the influence factors of illuminance distribution uniformity and the energy-saving ability of the indoor illumination control system, which consists of a white light-emitting diodes (WLED) matrix and a tabletop matrix. In the proposed illumination control method, comprehensive effects of time-invariant and time-variant sunlight of the outdoor environment, arrangement of the WLED matrix, iterative functions selected for illuminance distribution optimization, and compositions of WLED optical spectra are considered. The non-symmetrical spatial distribution of WLED-tabletop matrices, the optical spectrum selection of WLEDs, and the shifting sunlight intensity introduce obvious influence on (a) emission intensity and distribution uniformity of the WLED matrix and (b) receiving illuminance intensity and distribution uniformity of the tabletop matrix. Additionally, the selection of iterative functions, the WLED matrix dimension, the target error coefficient in the iteration, and the optical spectra of the WLEDs cause non-negligible influence on the energy saving percentage and iteration steps of the proposed algorithm, influencing the effectiveness and accuracy of the proposed method. Our investigation provides guidelines for the improvement of optimization speed and accuracy of indoor illumination control systems, and the method is hopefully to be widely applied in manufacturing industry and intelligent office buildings.

Symmetrical indoor visible light layout optimized by a modified grey wolf algorithm

The indoor visible light communication system's LED layout and power factor affect the uniformity of the received power. To reduce the mean square error (MSE) of received power, a symmetrical optimization strategy based on the modified grey wolf optimization algorithm (mGWO) is proposed and applied in the square, rectangular, and circular rooms with different numbers of LED arrays. The received power uniformity, SNR uniformity, bit error rate, and channel capacity of the optimized layout with the proposed method are improved compared to the classical layout. The comparison results show that the mGWO can find the optimal layout efficiently.