Vysílače pro bezvláknové optické difúzní sítě

Abstract

This work deals with mobile fiberless optical communications. Due to the huge area of this technology, this work is primarily fucused on use of the RGBY model. This model can communicate with 4 separate wavelenghts in visible spectrum and keep white light at the output, so it can be used also for illumination pusposes. Wireless data transmission is a huge area of interest today. The demand of user mobility and amount of transmitted data is increasing every day. Due to the high density of city population are radio technologies on the edge of the usability. The cell sizes of mobile operators are steadily decreasing to obtain the growing numbers of mobile phone users. Connecting via Wi-Fi is nowadays the significant problem, especially in 2,4 GHz band. Number of access points in the areas is usually higher than number of available channels. This leads to problem that channels are starting to repeat and mutually interfere with each other. Need for other technologies, that could eliminate this problems are constantly increasing. One of possible solutions are fiberless optical netwotks, which offers communication transparency, unlicensed band and thanks to the actual development of LED technologies also easier implementation to users needs. Instead of white LEDs this work uses multiple individual colors and diffuser to create white light. The current system capabilities with use of RGB (red, green and blue) model are insufficient so the system was extended with yellow. As a result we get RGBY system which better utilizes the visible spectrum and it is capable to create huge cellular systems for wide area coverage. Theoretical part of this work deals with the theory of visible light communication systems (VLC), their possibilities, challenges and applications. The practical part is focused on the design of RGBY communication system and its realization. In the final part the system functionality in the real conditions is validated.