  To study the effect of lack of up-to-date channel state information at the
transmitters (CSIT), we consider two-user binary fading interference channels
with Delayed-CSIT. We characterize the capacity region for such channels under
homogeneous assumption where channel gains have identical and independent
distributions across time and space, eliminating the possibility of exploiting
time/space correlation. We introduce and discuss several novel coding
opportunities created by outdated CSIT that can enlarge the achievable rate
region. The capacity-achieving scheme relies on accurate combination,
concatenation, and merging of these opportunities, depending on the channel
statistics. The outer-bounds are based on an extremal inequality we develop for
a binary broadcast channel with Delayed-CSIT. We further extend the results and
characterize the capacity region when output feedback links are available from
the receivers to the transmitters in addition to the delayed knowledge of the
channel state information. We also discuss the extension of our results to the
non-homogeneous setting.
