Low complexity MIMO receiver via maximum SINR interference cancellation

We propose a low complexity receiver structure for a multiple transmit antenna, multiple receive antenna (MIMO) system in the EDGE environment. In such a MIMO system, independent data streams are transmitted through different transmit antennas. In the proposed low complexity receiver structure, these data streams are separated and detected individually. The signal separation at the receiver is performed by the space-time interference cancellation filters. Each filter has a target data stream and intends to maximize the signal to interference and noise ratio (SINR) of that target data stream. Each filter is followed by a prefilter and a decision feedback sequence estimator (DFSE) which includes a feedback filter and a MAP sequence estimator. The maximum SINR (MSINR) interference cancellation comes in two flavors: blind and explicit methods. The blind MSINR method was first proposed in Liang et al. (1997) as a two-stage co-channel interference (CCI) suppression method with multiple receive antennas. We show that the blind MSINR method can be directly applied in the MIMO context and also derive another variation of the MSINR method, which we term the explicit MSINR method. While both methods achieve decent performance at low complexity, the explicit method utilizes the knowledge of all the training sequences and performs better than the blind method.