GDoF region characterization of the weak MIMO IC with No CSIT

Abstract

We characterize the generalized degrees of freedom (GDoF) region of an ergodic fading 2-user interference channel (IC) with multiple antennas at each node (MIMO) under the assumption that the channel realizations are known only at the receivers and not at the transmitters (No CSIT). We consider the weak interference scenario where the ratio — denoted by α — of the signal strength of the interfering links to that of the corresponding direct links in dB scale is assumed to be smaller than half. Assuming that transmitters and receivers have Mi, M 2 and N 1 , N 2 , antennas respectively, except from a small class where (M2 + N2) > min{Mi, Ni} > N2 > M2, we characterize the GDoF region of the weak IC for all other antenna configurations. We derive newer outer bounds to the GDoF which enable us bypass the use of full CSIT GDoF bounds as outer bounds for the No-CSIT scenario and therefore has the potential to be useful for analyzing other networks for which full-CSIT GDoF characterization is not available. The achievability of these upper bounds are then proved specifying explicit coding-decoding schemes.