Experimental Research On LDPC Code Performance In Atmospheric Laser Communication System

Laser communication has been widely used in various fields due to its high speed,large communication capacity,strong anti-interference ability,good security performance,wide bandwidth.Due to atmospheric absorption and atmospheric scattering and atmospheric turbulence movement,etc.,the link error rate will increase,the rate will decrease,the data loss,and even the link will be interrupted.The channel coding technology has strong error control capabilities,can effectively mitigate the effects of atmospheric turbulence effects,etc.,thereby greatly reducing the error rate of communication transmission and improving the reliability and stability of the communication system.At present,channel codes commonly used in the atmosphere include RS codes,Turbo codes,and LDPC codes.LDPC has been widely used in atmospheric laser communication systems because of its advantages of approaching Shannon's theoretical limit,flexible structure,low error leveling,parallel operation,low coding and decoding complexity,and hardware implementation.This paper studies the LDPC codes in atmospheric laser communication systems.Based on the analysis of the basic theory of laser atmospheric transmission,the present situation of channel coding in atmospheric laser communication system and the method of encoding and decoding are systematically described.The principle of encoding and decoding of LDPC codes is studied and analyzed in detail,and the matrix is adopted.The splitting technique and masking technique are used to encode LDPC,and an experimental atmospheric laser communication system is designed and constructed.The BERC code and traditional coding methods are tested in field experiments to improve the BER,and the experimental verification results are obtained.The theoretical simulation results were compared and analyzed.Under the same channel conditions,the optimized LDPC code has higher error correction performance than traditional channel coding.The simulation results are basically consistent with the experimental results.