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 α and the same channel uncertainty parameter β. The main challenge resides in the proof of the outer bound which is accomplished by a generalization of the aligned image sets approach.