| The most important problem of free-space optical communication is the atmospheric effects. In the paper, the questions appeared when laser transmitted in the atmospheric channel is measured and analyzed, then offered the results for the projects of free-space optical communications.It is firstly discussed the status of the development of the free-space optical communications in the paper. For the advantages of high data rate, good security, anti-electromagetic jamming, small volume and little weight etc., free-space optical communications has attracted many countries' attention. The influence of atmospheric turbulence to laser transmission is profoundly analyzed in the paper. Then, a model, based the atmospheric turbulence effects, is presented and simulated by MATLAB. At last, the working theory of encoder, decoder and optical transceiver of the optical wireless LAN are analyzed. The experiments about the system are done in the paper.The aim of this thesis is to proposal an atmosphere channel's model based on atmospheric turbulence theoretics according to different transmission conditions, and it was been validated by comparing the simulation results of the model with the real data collected. The main originalities and latest technologies used in the operation of the system are as following: 1. Connecting computers through laser in a LAN wirelessly, high speedily and cheaply by using the technology of free-space optical communication. 2. Designing the APC and ATC in the optical transceiver. 3. Using wavelength near 650nm, and making the system to leave out expensive telescope system.Free-space optical communication has the good practicability and will be competitive in the market application. More and more manpower and material resources is put to the fields in many countries. The paper has the important referenced value for the achievement of the free-space optical communication. |
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