The design of a rateless channel coding scheme for deep-space communication

In this paper, a rateless channel coding scheme is proposed for deep-space communication. Unlike the traditional fixed-rate coding schemes, in our scheme the coding rate is not designed as a fixed value before transmission, but adaptive to the channel variations resulted from the dynamically varied transmission distance and complex atmospheric conditions. Specifically, a Raptor code which is provided by a cascade structure is adopted for the data transmission. The pre-code of Raptor code is encoded with a linear-time progressive edge-growth algorithm which avoids tedious calculations by matrix transformation. Moreover, based on a joint iterative decoding method, the output degree distribution of our Raptor code is optimized so as to obtain good decoding performances. Comparisons are provided with respect to the fixed-rate coding schemes by numerical simulation, which shows that our proposed rateless coding scheme has better performance and is adaptively capacity-approaching for the deep-space data transmission.