Adaptive multiuser detection in dispersive channels with array observations

We present a multiuser receiver which is capable of operating in time-variant channels with severe multipath. For each active user, the receiver consists of a multi-input, single-output filter followed by a single-user adaptive equalizer. The array processing filter is chosen to maximize an averaged performance metric which measures reduction in the interference from multiple asynchronous cochannel users and the reduction in intersymbol interference caused by time spreading of the transmitted signal. The single-user adaptive equalizer that follows the array processing filter eliminates the remaining intersymbol interference prior to hard symbol decisions. Receiver performance is demonstrated using data obtained from two acoustic channels where two cochannel users are transmitting in shallow-water at 18 and 30 nautical miles from the receiver array