Centralized Relay Selection and Optical Filtering Based System Design for Reliable Free Space Optical Communication over Atmospheric Turbulence

The need for much better data rate in support for the applications having the high speed has gathered the attention to the development of Free space Optical communication technology (FSO). But the widespread usage of this technology is restrained by the several ill effects caused by the atmosphere on the propagation of optical signals. In order to mitigate such problems in the FSO communication, relay assistance has been employed and this serves the alternative to the spatial diversity. Free space optical (FSO) communication is a cost-effective and high bandwidth access technique, which has been receiving attention to recent commercialization successes. FSO get affected by the weather turbulence and it leads to severe problems in the transmission channels. In this paper, we proposed the Centralized Relay selection and Optical Filtering (CROF) for processing the signals in the FSO system which overcomes the environmental challenges. Initially, an effective relay is selected with the centralized switch and stay algorithm. This algorithm selects suitable relay for serial path transmission. Here, the serial path is considered for signal transmission in a free path and the distributed Greedy algorithm with serial transmission is utilized to obtain more information. Then atmospheric turbulence induced scintillation noise presented at the signal is eliminated through modified Kalman filtering. Finally, the performance of the proposed FSO system is evaluated in MATLAB simulation platform and these evaluations are analyzed for different atmospheric conditions like fog, haze, rain and clear weather. The performance evaluation shows that the proposed algorithm outperforms the non-cooperative scheme and an existing relay selection protocol and reliable communication with improved SNR and BER is achieved.