  An adaptive iterative decision multi-feedback detection algorithm with
constellation constraints is proposed for multiuser multi-antenna systems. An
enhanced detection and interference cancellation is performed by introducing
multiple constellation points as decision candidates. A complexity reduction
strategy is developed to avoid redundant processing with reliable decisions
along with an adaptive recursive least squares algorithm for time-varying
channels. An iterative detection and decoding scheme is also considered with
the proposed detection algorithm. Simulations show that the proposed technique
has a complexity as low as the conventional decision feedback detector while it
obtains a performance close to the maximum likelihood detector.
