Research Of Application On Unequal Error LDPC Encoding And Decoding In Satellite ATM Transmission Network

This thesis mainly discusses what kinds of unequal error LDPC codes are suitable for use in satellite ATM transmission network,and what encoding and decoding methods are used.First,the influence of bit error rate on ATM network transmission reliability in ATM network is compared by means of probability and statistics.From the calculation results,we can see that the first 5 bytes of each frame in ATM network transmission have greater impact on reliability.The traditional error correction coding scheme has not improved this point.By comparing the error correction coding schemes adopted in the satellite ATM transmission network both at home and abroad,the advantages and disadvantages of different schemes are analyzed,including the implementation steps of each scheme,the possible complexity of the implementation,the change to the existing network transmission format,the protection level of the reliability of the data,and the shortcomings.The comparison results show that only the unequal error LDPC codes can better correct more frame head errors,and the difficulty of encoding and decoding scheme has not been increased much,and high coding gain can be obtained.Therefore,the unequal error LDPC codes proposed in this paper are more suitable for the transmission of satellite ATM networks.Secondly,this thesis also describes the research results of the construction and encoding and decoding algorithm of LDPC codes at home and abroad.Based on these studies,we propose our own idea of constructing unequal error LDPC codes.According to the data bits needed to be protected by the satellite ATM exchange data,we can generate the check matrix of new unequal error LDPC by some random shifting identity matrix.The element of check matrix can be adjusted flexibly according to the position of the frame selected to protect,so as to realize the key function of correcting the header error.Finally,simulation results are given to illustrate the application results of the unequal error LDPC codes constructed in the satellite ATM switching system.The coding algorithm of the code and the BP decoding algorithm in the probability domain are easy to realize.As long as the code length is long enough and the code rate is suitable,the error correction of the ATM cell can be realized,and the transmission reliability of the satellite ATM transmission system is ensured.