Improved turbo-equalization, with application to bit interleaved modulations

Turbo-equalization has been proposed as a powerful means for recovering unknown symbols sent through frequency selective channels. Most algorithms proposed so far were designed in the framework of a binary symbol alphabet, and then extended to modulations with a larger number of states. Moreover symbol interleaving was mainly considered. This paper improves existing algorithms in that our algorithm (i) exhibits better performance when used with large constellations, and (ii) can be used in conjunction with bit interleaving and thus applies to bit interleaved coded modulations (BICM), which are now frequently used in wireless transmissions. Two variants of the algorithms are presented, namely a turbo-equalizer and a turbo-canceler.