Joint Illumination-Communication Optimization in Visible Light Communication

One major characteristic of visible light communication (VLC) is its two-fold functionality of illumination and communication. Therefore, this paper considers joint optimization of illumination-communication in an indoor VLC system where light-emitting diode (LED) transmit-power can be adjusted. The aim is to render uniform illumination levels while guaranteeing users' communicating and illumination requirements. So the problem is formulated as optimization under constraints. A novel harmony annealing (HA) intelligent search algorithm is developed to solve it. HA adequately utilizes previous optimized information in next search trials. Meanwhile, multiple search directions are enhanced to avoid solutions being trapped in local optimum. Thus, HA's search efficiency and global search ability are improved. Through simulation, advantages of HA are identified and validated by comparing with conventional intelligent search algorithms. Analysis of the numeric results gives an indication that the illumination uniformity is increased while user's received signal-to-noise ratio (SNR) is sufficient for keeping BER<10-6.