The Research On Turbo Coding And Decoding Algorithm For Deep Space Communication

With the development of space technology, as well as ensuring Chinese advanced degree of space research in the future, it is necessary to do research on the field of deep space exploration. In that case, our country may have the ability to improve her power. One of the key technologies of deep space communication is channel code. There are differences between deep space communication and the common space communication. Because the former one has some characteristics, such as extending information transmission, and seriously reducing signal energy, it is necessary to ensure the information transmission band and the exactness by using the special means.The channel coding technology can avouch the reliable message transmission and have some considerable coding gains. Turbo code was introduced by C.Berrou in 1993. Turbo code can achieve the error correcting capacity close to the Shannon-limit with reasonable decoding complexity, provided that the code words are long enough. Turbo code also has better capability in resisting attenuation and disturbance, so it has great potential applications in deep space communication with bad channel condition. Since being proposed, it has become the research hotpot in the error-correct coding area. This paper focuses on the theory of turbo code and its application in deep space communication.In this paper, turbo code is studied deeply from theory in order to find the reason why it has so good performance and to find all kinds of factors that influence its performance. We put the emphases on the soft output Viterbi algorithm (SOVA), which is one of turbo code's decoding algorithms, and presents the derivation and computation step of the SOVA decoding algorithm. After presenting SOVA and MAP decoding algorithms and analyzing four kinds of decoding algorithms, the paper makes a comparison among the different decoding algorithms by emulation analysis, and analyzes the time complexity of various algorithms, and then contrasts them.In the last part of this paper, according to the criterion recommended by the Consultative Committee for Space Data Systems (CCSDS), including code rate,...