Study And Realization Of Multimedia Signal Processing And Digital-Filteringin In Wireless Optical Communication System

Wireless optical communication is a new type of broadband access technology, which combines the advantage of both wireless communication and fiber communication. Wireless optical communication uses light as carrier wave and travels through atmosphere to achieve high speed point-to-point and point-to-multipoint communication.The work of this thesis is based on visible light communication demo system and the key device and technology in UV communication system. The main work and point of innovation are shown below:Firstly, with the breakthrough of data rate in visible light communication, multimedia service has become a focus of attention. Visible light communication demo system with embedded system is significant in building mature and small visible light communication system in the future. In this thesis, multimedia signal processing is achieved with an arm embedded system. A MP3decoder is accomplished, and a multimedia streaming software called VLC is ported to the embedded system.Secondly, AlGaN ultraviolet is the third generation of ultraviolet detectors with a low price and high sensitivity. There is little research about the application of this detector in ultraviolet communication. This thesis mainly focuses on the noise of the AlGaN detector and its amplifying circuit. According to the experiment result, receiver sensitivity is obtained, which offers references of LED power at the transmission side in an OOK system. Moreover, the thesis studies and accomplishes two digital-filtering methods to decrease the major noise in the receiver with an experimental validation.Thirdly, current research of ISI in ultraviolet communication is little. The thesis studies channel distortion in ultraviolet communication system based on the ultraviolet single-scattering model. The thesis analyses different equalizing algorithms, such as forcing-zero, adaptive equalization, decision feedback, blind equalization and so on, and compares their performance in the ultraviolet single-scattering model. Finally, forcing-zero equalizer is realized.