Turbo Detection for MIMO Systems Using a List-Sequential Detector : Improved Soft Output by Path Augmentation

Bit-interleaved coded modulation with iterative detection for MIMO systems demands an efficient APP detector that delivers soft information about the coded bits. The list-sequential detector is a reduced-complexity approximation to an exhaustive APP detector. It uses a tree search employing the stack algorithm to find dominant terms of the log-likelihood ratio (LLR). We show how incomplete tree paths have to be augmented to improve LLR reliability.