On the Capacity and Degrees of Freedom Regions of MIMO Interference Channels with Limited Receiver Cooperation

TL;DR

This paper characterizes the approximate capacity and degrees of freedom regions of two-user MIMO interference channels with limited receiver cooperation, revealing how cooperation impacts capacity and degrees of freedom.

Contribution

It provides the first approximate capacity region for MIMO interference channels with limited receiver cooperation, including generalized degrees of freedom analysis.

Findings

Capacity gap depends on total receive antennas, not channel specifics.

Receiver cooperation enhances degrees of freedom up to a certain backhaul capacity.

Generalized degrees of freedom improve from a 'W' to a 'V' curve with increased cooperation.

Abstract

This paper gives the approximate capacity region of a two-user MIMO interference channel with limited receiver cooperation, where the gap between the inner and outer bounds is in terms of the total number of receive antennas at the two receivers and is independent of the actual channel values. The approximate capacity region is then used to find the degrees of freedom region. For the special case of symmetric interference channels, we also find the amount of receiver cooperation in terms of the backhaul capacity beyond which the degrees of freedom do not improve. Further, the generalized degrees of freedom are found for MIMO interference channels with equal number of antennas at all nodes. It is shown that the generalized degrees of freedom improve gradually from a "W" curve to a "V" curve with increase in cooperation in terms of the backhaul capacity.