Sphere detectors for robust iterative detection and decoding under channel estimation errors

An iterative sphere detector is presented that takes into account channel estimation errors. It evolves from the class of the most contributive 2N generalized Schnorr-Euchner detectors for N ¿ 2. The later were recently introduced for iterative detection and decoding receivers of ST-BICM over flat fading channels under the assumption of perfect channel state information at the receiver. For the new detector, the log-likelihood ratio of the a posteriori probability mass function of coded bits is derived under the assumption of nonzero but uncorrelated channel estimation errors. Simulation results show that the new detector provides performance gain over the mismatched one and in some cases removes the error floor.