An Error Correction Coding For Deep Space Communications

As the research of the error-correction coding theory going deep,the error-correction code has been widely applied, especially after the technique of VLSI making great progress. As the very important Error-correction code of all kinds, linear convolutional codes have been adopted by most communication system. (2,1,7) linear convolutional code is a optimal code with short restriction length and good ability of error correction, and its coder and decoder can be easily make out. It was recommend as one of the standard of Error-correction system by NASAS ESA and CCSDS etc.. In this subject it emphasizes on the performance of (2,1,7) convolutional code on telemetry communication channel, and measures the actual value of the progress of performance of the simulative system after using error corrcting skill. First, in order to easily and thoroughly explain the technique of convolutional codes, some relative theory has selectively been referred to, such as stochastic progress information theory and Error-correction theory. And then it comes down to the usual methods appling to the convolutional codes, such as coding polynominah tree diagram~. state diagrams trellis diagram etc.. In this subject it also designed the circuit diagram of the coder and provided part of the procedure code which was used to draw the trellis diagram of (2,1,7) convolutional code and described the Viterbi algorithm in detail.At the same time it prepared the practical (2,1,7) convolutional coder and Viterbi decoder which have advanced target and good performance,and designed a testing system and a method to test the asymptotic code gain of the coder and decoder in this system. The asymptotic code gain of the testing system is high to 6.ldB@IO~, exceeding the known research result (5.6dB@1O~) which was supported by ESA.