Deterministic blind modulation-induced source separation for digital wireless communications

In this paper, we present a new simple deterministic blind source separation algorithm, which is based on modulating the same data symbol sequence with different code sequences and transmitting the resulting modulated data symbol sequences through different antennas. The algorithm does not exploit the finite alphabet property of the data symbols. As a result, no iterations are required, and convergence is not an issue. Instantaneous mixtures (frequency-flat fading), as well as convolutive mixtures (frequency-selective fading), can be handled. In the case of a convolutive mixture, the difficulties that occur when the users have unequal channel orders are avoided. Moreover, the proposed algorithm is robust against channel order underestimation.