On the influence of substream ordering for MIMO decision-feedback detectors with higher order modulation

The performance of different multiuser detectors with soft decision-feedback is evaluated in a transmission system with multiple transmit and receive antennas (MIMO) and higher order modulation. Specifically, the influence of the detection order on the detector performance is investigated. It is found that the unbiased MMSE soft decision-feedback detector with a simple pre-estimation ordering algorithm, that takes the crosscorrelation between substreams into account, practically achieves the same performance as the more complex V-BLAST detector.