Study On Optimization Of Layout Of LED Lights Based On Indoor Visible Light Communication System

Visible light communicaiton is a kind of wireless optical communication technology derived from the development of white LEDs.It takes light signals as the carrier and atmoshphere as transmission medium, therefore building wireless optical network.It is a supplement of exisisting radio frequency communication which possesses many advantages such as high safety, no spectrum certification, high transmission rate and so on. Therefore, it has become one of the key technologies in the development and ultilation of spectrum resources facing the severe situation of current spectrum crisis and fierce compition.As the main component of visible light communication system, optical transmission antenna and receiving antenna, its performance directly influences the reliability of the whole communication system and stability of signal transmission.The layout of LED lights largely determines the performance of transmission antenna.Therefore, in this paper, it focuses layout of LED lights on study of indoor conditions of office lighting and local conditions which are applied in hospital,airport and indoor lamp lighting.The research contents are as follows:1. Research on system of the white LED lights are carried out.Then, the chanel model is briefly introduced.Theoretical calculation models of illumination, impulse response, DC gain and received power are given in two links.Last,nosie,signal-to-noise ratio and inter-symbol interference are analyzed and discussed.2. The layout of LED lights is discussed in indoor office lighting. An optimization design in layout of lighting is used based on the assessment criteria of energy saving and minimization of mean square deviation compared to the existence of original layout in the model room.Quantitively calculate the distribution of illumination and received power in LOS and NLOS links.Then analyze the relation between SNR(ISI) and field of view of optical antennas.So, field of view of optical antennas is given in the scope of 40 to 50 deg. based on the stallments of LED lights to avoid the blind area,attain high SNR and reduce the influence of ISI.And design a software on illumination and received power in indoor VLC system accordingly based on MATLAB GUI.Users can use the software to observe the corresponding distribution which acts as a guide to the layout of LED lights.3. The design of layout of LED lights based on three kinds of algorithms are adopted in short distance of local illumination of hospital,airport and indoor lamp lighting.Idea,design principle,basic process and characteristics of genetic algorithm,simulated annealing algorithm and simulated annealing hybrid genetic algorithm are introduced.The calculation model of illumination and optimized coordinate points through these three algorithms are given under the local illumination.Then layout of LED lights are simulalted using Tracepro.Analyze the parameters of illumination and flux of the receiving surface through these three parameters.Finally,the simulation results are compared and analyzed, and adaptability and characteristics of each algorithm are also given so as to illustrate SAHG algorithm which combine the advantages of GA and SA algorithms is more applied to the layout of multi LED lights of indoor VLC system.