A low-complexity decoding algorithm for concatenated tree codes

This work considers a modified belief-propagation algorithm with two way scheduling for concatenated tree (CT) codes in which tree codes are employed as constituent codes. It will be shown that constituent tree codes can be efficiently decoded with the modified algorithm. Thus, by repeatedly using the modified BP algorithm for the constituent tree codes, CT codes can be decoded in an efficient way. Moreover, we show that the modified algorithm is especially suited for low complexity hardware implementation. Finally, a simple analysis technique for error-correcting performances of tree codes will be presented.