A method of performing spatial processing at a receiver in a wireless multiple-input multiple-output, MIMO, communication system, comprising: obtaining a plurality of received symbol streams for a plurality of data symbol streams sent via a plurality of spatial channels of a MIMO channel in the wireless MIMO communication system, wherein spatial processing is performed at a transmitter with steering vectors, which are estimates of transmitter steering vectors required to orthogonalize the plurality of spatial channels; receiving orthogonal pilot transmissions from a plurality of antennas at the transmitter; obtaining an estimate of a channel response matrix for the MIMO channel, wherein the estimated channel response matrix is obtained based on the received orthogonal pilot transmissions; and performing spatial processing on the plurality of received symbol streams with a spatial filter to obtain a plurality of filtered symbol streams, which are estimates of the plurality of data symbol streams, wherein the spatial filter has a response derived based on a minimum mean square error, MMSE, criterion that minimizes mean square error between the plurality of filtered symbol streams and the plurality of data symbol streams, characterized in that the spatial filter response is derived in accordance with the following formula: W ̲ = V ̲ ^ H ⁢ H ^ ̲ H H ^ ̲ ⁢ V ^ ̲ ⁢ V ^ ̲ H ⁢ H ^ ̲ H + φ ̲ nn - 1, where W is the spatial filter response, V̂ is a matrix of the steering vectors used for spatial processing at the transmitter, Ĥ is the estimated channel response matrix, V̂ H and Ĥ H denote the Hermitian or conjugate transpose of V̂ and Ĥ respectively, and φ nn is an autocovariance matrix of noise at the receiver. obtaining a plurality of received symbol streams for a plurality of data symbol streams sent via a plurality of spatial channels of a MIMO channel in the wireless MIMO communication system, wherein spatial processing is performed at a transmitter with steering vectors, which are estimates of transmitter steering vectors required to orthogonalize the plurality of spatial channels; receiving orthogonal pilot transmissions from a plurality of antennas at the transmitter; obtaining an estimate of a channel response matrix for the MIMO channel, wherein the estimated channel response matrix is obtained based on the received orthogonal pilot transmissions; and performing spatial processing on the plurality of received symbol streams with a spatial filter to obtain a plurality of filtered symbol streams, which are estimates of the plurality of data symbol streams, wherein the spatial filter has a response derived based on a minimum mean square error, MMSE, criterion that minimizes mean square error between the plurality of filtered symbol streams and the plurality of data symbol streams, characterized in that the spatial filter response is derived in accordance with the following formula: W ̲ = V ̲ ^ H ⁢ H ^ ̲ H H ^ ̲ ⁢ V ^ ̲ ⁢ V ^ ̲ H ⁢ H ^ ̲ H + φ ̲ nn - 1, where W is the spatial filter response, V̂ is a matrix of the steering vectors used for spatial processing at the transmitter, Ĥ is the estimated channel response matrix, V̂ H and Ĥ H denote the Hermitian or conjugate transpose of V̂ and Ĥ respectively, and φ nn is an autocovariance matrix of noise at the receiver.