Studying On Receiving Technology In MIMO Wireless Optical Communication System

With the emergence of high-performance lasers and optical devices, optical wirelesscommunication, also known as the atmospheric optical communication has seen rapiddevelopment in the second half of the20th century. Wireless optical communication hasmany unique advantages, such as high output rate of transmission, better privacy, and freefrequency license etc.. However, because the optical signal transmitted in the atmosphere isimpacted by atmospheric interference, such as atmospheric turbulence and background light,optical signal channel declines, which seriously affects system stability and reliability of theatmospheric optical communication systems, and limits communication rate increase ofatmospheric optical communication.In recent years, Multiple-Input Multiple-Output (MIMO) technology as an effectivetechnology to restrain random decline and increase the channel capacity of channel isintroduced to the wireless optical communication field to improve the signal quality ofcommunication in atmosphere. This thesis, based on microwave MIMO communicationtechnology, combining the characteristics of optical wireless communication system,proposes the scheme to improve channel fading in optical wireless communication systemusing MIMO wireless optical communications. First, the optical signal interference in theatmospheric propagation was introduced, as well as the characteristics of optical signalpropagated in the atmosphere, second introduced a general principle and characteristic ofMIMO system and the key techniques in MIMO systems. Then, combining optical wirelesssystem and MIMO technology, the main structure of MIMO wireless communication systemwas offered and the basic principles of various parts of the MIMO wireless communicationsystem and parameter characteristics for optical wireless communication system areanalyzed. Based on earlier theory analysis and simulation, an MIMO Wireless lightcommunication experimental system has been built, and the experiment and analysis of the improvement for optical array receives and light signal have been made. It has beenimproved that the optical array antenna in MIMO system can improve the SNR of wirelesslight communication, and light filter consisted of fiber grating can further optimize the lightsignal’s quality.