Block-encoded transmissions of a multi-antenna terminal unit are effectively detected in the presence of co-channel interfering transmissions when the base station has a plurality of antennas, and interference cancellation is combined with maximum likelihood decoding. More specifically, the signals received at the base station antennas are combined in a linear combination that relates to the channel coefficients between the various transmitting terminal units and the base antennas. By selecting proper coefficients for the linear combination and choosing probable transmitted signals that minimize a minimum mean squared error function, the signals of the various terminal units are canceled when detecting the signal of a particular unit. In another embodiment of the invention, the basic approach is used to obtain an initial estimate of the signals transmitted by one terminal unit, and the contribution of those signals is removed from the received signals prior to detecting the signals of other terminal units. In still another embodiment, the decoding process is repeated at least twice by detecting the signals of the terminal units in a different order, and selecting the detections that produce the lowest uncertainty measure. The disclosed techniques are viable for any number K of terminal units transmitting concurrently over a given channel, where each terminal unit is using a space-time block code with N transmit antennas, and a base station has at least K receive antennas.