The blind separation of non-stationary signals by only using the second order statistics

Lathauwer and Comon (see Signal Processing, vol.73, no.1-2, p.3-4, 1999) state that for the last 10 years, source separation has raised an increasing interest, partly because it has been discovered that space-time approaches will play an essential role in future radio communications. In the case of an instantaneous mixture (memoryless mixture or channel), many algorithms are proposed to solve the blind separation problem. In the general case (where no special assumption is assumed), the high order statistics (i.e. fourth order) are used. By adding special assumptions, algorithms and criteria can be simplified. In this paper, we discuss and present how the separation of a non-stationary signal can be done using only second order statistics