On the capacity of a class of dual-band interference channels

We consider a two-transmitter two-receiver dual-band Gaussian interference channel (GIC) which is motivated by the simultaneous use of both the conventional microwave band and the unconventional millimeter wave (mm-wave) band in future wireless networks where the traditional microwave band is complemented by additional spectrum in the mm-wave band. A key modeling feature of the mm-wave band is that due to severe path loss and relatively small wavelength, it must be used with highly directional antennas, and thus the transmitter is able to transmit to its intended receiver with negligible to no interference to other receivers. For this model, we derive some sufficient conditions on the channel gains under which the capacity of this type of dual-band GIC is determined. Specifically, these conditions are classified as when microwave band channel gains have (a) weak interference, i.e., both the cross channel gains are less than 1 and (b) mixed interference, i.e., only one of the cross channel gains is less than 1, while the channel gains in the dual-band GIC satisfy certain additional conditions in each case.