Blind identification of FIR channels with multiple users via spatio-temporal processing

A new method is proposed for blind identification of possibly nonminimum phase FIR channels with multiple users. The technique exploits the structure of the signals received by an antenna array in both the temporal and spatial frequency domains. Although in the single antenna case it is necessary to use cyclostationary signals or higher order statistics to identify the magnitude and phase of the channel, the present authors circumvent such a requirement by exploiting certain multichannel features of the array. They show that if multiple users are present, the nonminimum phase channels associated with each user can still be identified from the second-order statistics, provided additional spatial structure exists.