Aligned Image Sets and the Generalized Degrees of Freedom of Symmetric MIMO Interference Channel With Partial CSIT

The generalized degrees of freedom of the two-user symmetric multiple input multiple output interference channel are characterized as a function of the channel strength levels and the level of channel state information at the transmitters. In this symmetric setting, each transmitter is equipped with M antennas, each receiver is equipped with N antennas, and both cross links have the same strength parameter alpha and the same channel uncertainty parameter beta. The main challenge resides in the proof of the outer bound which is accomplished by a generalization of the aligned image sets approach.