A new outer bound on the capacity region of Gaussian interference channels

The best known outer bound on the capacity region of the two-user Gaussian interference channel is given as the intersection of regions of genie-aided outer bounds, in which a genie provides extra side information to the receivers. In this paper, we present a new outer bound that does not resort to a genie-aided channel but make use of auxiliary random variables. In order to obtain such bound, we introduce a conditional version of the worst additive noise lemma. The new bound is shown to be tighter than genie-aided bounds for certain range of parameters.