The Research Of Wireless Optical Digital Communication For Indoors

There are many respects influence the design of indoor wireless optical digital communication system. The characteristics of channel are very important for it. The main research works of this paper include the analysis of the characteristic of the channel for indoor wireless optical digital communication, the methods of equalization, the estimation of the WOC channel etc.Based on the project of evaluation the characteristics of the infrared wireless communication channel, we have defined a new mathematical model of the impulse response and time delay of WOC channel. We use modificatory Lambertian Law describe the diffuse characteristics of the room surfaces, which can distinguish the diffuse effects for different surfaces of the room. The magnitudes of light-of-sight and diffuse response of channel, the characteristics of several channels have been analyzed and simulated. Under motion condition, there is a maximum time delay for indoor WOC channel. The analyses of channel characteristics of light-of-sight channel, diffuse channel, quasi-diffuse channel under imaging and non-imaging receive are given. The results demonstrated that the change of FOV and the change of the position of receiver have serious effects to the characteristics of the channel. The methods of this paper are contributed to the design a robust infrared communication channel.The adaptive equalize methods are introduced first to the study of WOC. We purpose a Decision-Feedback adaptive-FIR equalizer can be used in multipath WOC channel, in which the quality of the WOC channel can be improved. The output decision of our method was made by Viterbi algorithm, and the results were compared with that from Hard-decision situation. The simulation results demonstrated that the step factor of adaptive equalizer must less than 0.06. The other modified methods for WOC channel are given also.The ability adaptive to the change of WOC channel is so important that we will discuss the blind identification and channel estimate herein. Based on the Second-Order Statistics, denoising, channel estimate of special WOC receiver-transmitter (RT) configuration indoor are obtained in our simulations. The simulated range of SNR is high up to30dB. The main errors under those WOC condition, are the survivals of singular value decomposition of autocorrelation function and the denoising, which obtained by our detail analysis. The estimate results which coincide with oral channel quantities in different SNR condition is achieved also.The receive methods for WOC system are discussed here. The characteristics of non-correlated and correlated receive configuration are analyzed. The principles of modulation and demodulation of WOC are motioned, and we have compared BER, mini transmitted optical power needs for different modulation conditions. For construct wide-band system, we have study the receive circuit and the noise of WOC in details.Based on the discuss of home network and inner data bus, we given out an configuration mainly on residential gateway, and the key in control injunctions was transferred by wireless channel. Some detail depict on sensing units were described conjuction with residential interconnect ground on object method. To access digital detection sensing data and to get adaptive parameter adjust function, a special data frame structure was given and discussed.