LMMSE channel estimation for MIMO W-CDMA with out-of-cell interference mitigation

Abstract

An LMMSE channel estimator is proposed for the downlink of a MIMO W-CDMA system. The estimation takes into account intra-cell and out-of-cell interference, as well as receive-side spatial correlation. Efficient numerical methods are applied to solve the resulting large block Toeplitz linear equation sets. Various simplifying assumptions about the prior knowledge of second-order statistics used by the estimator are investigated, providing a performance vs. complexity tradeoff. Link level simulation results of a MIMO HSDPA system show that LMMSE channel estimation together with out-of-cell interference-aware equalization yield performance throughput gains of up to 30% over a correlation based channel estimator.