  This paper explores the two-user Gaussian interference channel through the
lens of a natural deterministic channel model. The main result is that the
deterministic channel uniformly approximates the Gaussian channel, the capacity
regions differing by a universal constant. The problem of finding the capacity
of the Gaussian channel to within a constant error is therefore reduced to that
of finding the capacity of the far simpler deterministic channel. Thus, the
paper provides an alternative derivation of the recent constant gap capacity
characterization of Etkin, Tse, and Wang. Additionally, the deterministic model
gives significant insight towards the Gaussian channel.
