Error Control Techniques

The error-control system can increase the transmission reliability of communication system, and reduce the emission power and the capacity of the communication apparatus, so it is extensively applied in digital transmission system, for example, satellite communication system, mobile communication system, data storage and so on. Coding gain is an important index for the error control system. Viterbi algorithm is a kind of maximum likelihood decoding method, which can obtain high decoding speed and cost fixed decoding time, so it is widely used in deep space communication. (2,1,7) nonsystematic convolutional codes are optimal convolutional codes on the same code length and information bit length condition, so they are adopted as space standard codes by CCSDS(Consultative Committee for Space Data Systems). In the subject, the error-control project consisting of convolutional coder and viterbi decoder is adopted. The viterbi decoding algorithm is studied in the paper. An improved viterbi algorithm of DSP generation is brought up to, and a new coding gain testing system is designed. The system tests the coding gain of the error-control system, and the coding gain is 9.4dB which exceeds the proposed index. At last, some suggestions are presented for the work in the future.