On the optimality of zero-forcing and treating interference as noise for K-user MIMO interference channels

In this work, we first establish that for the class of interference channels identified by Geng et al. where treating interference as noise (TIN) is optimal from the generalized degrees-of-freedom (GDoF) perspective, if the number of antennas at each node is scaled by a common constant factor, then the GDoF region scales by the same factor almost surely, and the TIN scheme remains optimal for the entire GDoF region. Next, we demonstrate that for K-user MIMO interference channels with different antenna numbers for transmitters and receivers, there exist non-trivial parameter regimes where a simple scheme of zero-forcing strong interference and treating the others as noise achieves the sum GDoF.