  An inner bound to the capacity region of a class of deterministic
interference channels with three user pairs is presented. The key idea is to
simultaneously decode the combined interference signal and the intended message
at each receiver. It is shown that this interference-decoding inner bound is
tight under certain strong interference conditions. The inner bound is also
shown to strictly contain the inner bound obtained by treating interference as
noise, which includes interference alignment for deterministic channels. The
gain comes from judicious analysis of the number of combined interference
sequences in different regimes of input distributions and message rates.
Finally, the inner bound is generalized to the case where each channel output
is observed through a noisy channel.
