An iterative groupwise multiuser detector for overloaded MIMO applications

We consider a narrowband multiuser system in which several transmitting users are received through a synchronous, flat fading channel at an antenna array. The paper introduces a multiuser detection technique that combines group wise detection with iteration. It is well suited to overloaded conditions, where there are more transmitter antennas than receive antennas. The soft decisions it uses internally also make it suitable as a detector in a concatenated structure. Its performance and computation can be traded off through selection of group size. A variant of the algorithm achieves further computation reduction by incorporating a soft sphere detection core.