MAP decoding for satellite channels

Error correction coding can be used to mitigate fading and interference in wireless communication systems. Decoding is most effective when soft information is fed to the decoder. Practical receivers often have a concatenation of decoders, such as an equalizer followed by an error correction decoder. Hence, the first decoder must generate soft information for the second decoder. This paper considers generation of maximum a posteriori (MAP) soft information at a bit level and presents an algorithm to generate this soft information. The algorithm is applied to a turbo decoder and an equalizer-Viterbi decoder operating on satellite channels with Ricean fading