Blind equalization and channel estimation for multiple-input multiple-output communications systems

Equalization and estimation of the matrix impulse response function of MIMO digital communications channels in the absence of any training sequences is considered. An iterative, Godard (1980) cost based approach is considered for spatio-temporal equalization and MIMO impulse response estimation. Stationary points of the cost function are investigated and it is shown that all stable local minima correspond to desirable minima when doubly infinite equalizers are used. The inputs are extracted and cancelled one-by-one. The matrix impulse response is then obtained by cross-correlating the extracted inputs with the observed outputs. Identifiability conditions are analyzed. Computer simulation examples are presented to illustrate the proposed approach.