Analysis of forward error correction schemes for different coding rates in free-space communication

FSO communication provides high band-width, low-latency data transmission over optical beams to offer an alternative mode for communication over wires. It will suffer severely from disturbances brought about by atmospheric disturbances due to turbulence, rain and fog which will result in an increased Bit Error Rate. Thus, a solution offered was the correction of errors without the overhead of retransmission in systems like LDPC, Reed Solomon, Polar, Turbo code, among others. In this paper, we do the comparative analysis of these FEC techniques for FSO systems. The study high lights LDPC codes as one of the most efficient FEC technique to the superior error correction capability, low decoding complexity, and near optimal performance in challenging conditions. We analysis the performance of LDPC codes for various coding rates and iterations by running MATLAB simulations and present optimal configurations that maximize coding gain. The results indicate that an LDPC code rate of 2/3 with 12 decoding iterations provides the optimal compromise between error correction performance and bandwidth efficiency. In this way, this paper illustrates the effectiveness of LDPC codes as a powerful method to enhance the reliability of the FSO system and gives some valuable suggestions on its use in modern communication technologies.