Turbo-equalization applied to trellis-coded-modulations

In this article, a turbo-equalizer for TCM is investigated. The receiver is composed of a symbol detector or an equalizer realizing soft-output equalization, a deinterleaver, a soft-input soft-output channel decoder based on the a posteriori probability (APP) algorithm. A soft information provided by the decoder is then available and is re-used in the equalization step as is done in the classical scheme of turbo-equalization. The case of a APP algorithm used as an equalizer is investigated. A specific computation, iterating probabilities rather than extrinsic information, allows the application of turbo equalization to TCM. Simulations of this iterative receiver are done.