Combining beamforming with MMSE Alamouti multiuser interference cancellation receiver

The minimum mean square error (MMSE) interference cancellation (IC) technique exploits the algebraic structure of the Alamouti space-time block code (STBC) to suppress one multiuser interferer with only one additional antenna in multiple-input multiple-output (MIMO) communication scenario. However, the performance is suboptimal. A receiver structure that concatenates optimum receiver beamforming with MMSE IC technique is proposed to improve the bit-error-rate (BER) performance. Prior to the MMSE IC, two beamformers suppress cochannel interference (CCI) independently while preserving orthogonality of the MIMO channel To adopt beamforming, the MMSE IC process is modified. The array gain provided by the two beamformers brings the BER performance improvement of the original scheme.