Performance Evaluation and Optimization of Indoor Visible Light Communication Systems

Abstract

In this thesis, we propose a range of LED deployment schemes for indoor mobile visible light communication (VLC) systems. The thesis has investigated the performance of such systems for a number of cases considering LED deployment, design strategies, illumination and the use of soft computing techniques. LED deployment strategies include (i) uniform distribution; (ii) centralised LED array distribution; and (iii) single line LED patterns with horizontal, vertical and diagonal placements. newline newlineIt has been established that, the overall transmit power of a VLC system can be optimized by means of dynamic control of LED semi-angle. To enhance the system performance, PSO and HypEA heuristic algorithms have also been adopted. Further, the average outage area ratio has been studied for a moving receiver along with the characterization of root mean square (RMS) delay indicating the reduced level of inter-symbol interference (ISI). Consequently, the average speed of the transmission for these LED based design models have been compared so as to employ the best mechanism for the purpose of network deployment. newline newlineIt is further revealed that, HypEA, which is implemented for the first time, is computationally more efficient and offers 0.571 Gbps using 25WLED power with 18o semi-angle in the optimal design scenario. In addition, it is shown that, with HypEA the average data rate is about 2 Gbps using only 42 watt LED power at 10o semi-angle. The trade-off between LED power and the data rate is also investigated. Further, it presents that HypEA achieved the desired solution objective in just 20 generations as compared to 100 generations through PSO technique. Further, the investigation shows that the HypEA technique is able to reduce the LED resources for a given objective function by a margin of 12.5 percent in comparison to the PSO technique. newline newline