Blind channel estimation for orthogonal STBC in MISO systems

The paper presents a closed-form blind channel estimation scheme for Alamouti´s and other orthogonal space-time block codes. Unlike other blind algorithms, the scheme is able to estimate the channels, to within a phase constant, in multiple-input single-output systems, i.e., systems that employ only one receive antenna. The channel matrix is estimated from the eigenvalue decomposition of the fourth order cumulant matrix of the output signal. The performance of the scheme depends upon the accuracy of the estimated cumulants, and thus a scheme to improve the cumulant matrix estimate is suggested. Using these improved cumulants, the algorithm performs very well in slowly fading channels.