Channel estimation for O-STBC MISO systems using fourth-order cross-cumulants

This paper proposes several algorithms to recover the transmitted signals in systems with multiple antennas that make use of orthogonal space time block code (O-STBC) to attain full transmit diversity. We interpret the scheme proposed by Alamouti in [1] and half-rate systems presented in [2] as classic blind source separation (BSS) problems where the received signals (observations) are instantaneous mixtures of the transmitted signals (sources). In order to recover the sources, we first propose to perform an eigenvalue decomposition of matrices containing fourth-order cross-cumulants of the observations. Subsequently, we show that the performance of this approach can be improved by doing a simultaneous diagonalization of the cumulant matrices. This second approach can be interpreted as a particular case of Joint Approximate Diagonalization of Eigen-matrices (JADE) algorithm for systems where the mixing matrix is orthogonal.