Interference Mitigation and Signal Enhancement for Multiuser MIMO Interference Channels With Redundant Antennas

For a transceiver pair in a multiuser Gaussian interference channel with multiple antennas, if the number of transmit antennas is greater than the number of receive antennas, then in an equivalent virtual channel this transceiver pair has redundant transmit antennas. These redundant antennas do not contribute to the transmission to the intended receiver, however, may generate interference to other receivers. The optimal way to use these redundant antennas to mitigate interference and enhance the useful signal is studied, under the assumption of perfect channel state information, channel distribution information, and imperfect channel state information at the transmitter side, respectively.