att_abstract={{In this paper, we study the impact of different channel output feedback
architectures on the capacity of the two-user interference
channel. For a two-user interference channel, a feedback link can
exist between receivers and transmitters in 9 canonical architectures
(see Fig.~
ef{fig:allcombs}), ranging from only one feedback link to
four feedback links. We derive the exact capacity region for the
symmetric deterministic interference channel and the constant-gap
capacity region for the symmetric Gaussian interference channel for
all of the 9 architectures. We show that for a linear deterministic
symmetric interference channel, in the weak interference regime, all
models of feedback, except the one, which has only one of the receivers feeding back to
its own transmitter, have the identical capacity region. When only one of the receivers feeds back to its own transmitter, the capacity region is a strict subset of the capacity region of the rest of the feedback models in
the weak interference regime. However, the
sum-capacity of emph{all} feedback models is identical in the weak
interference regime. Moreover, in the strong interference regime all
models of feedback with at least one of the receivers feeding back to
its own transmitter have the identical sum-capacity. For the Gaussian
interference channel, the results of the linear deterministic model
follow, where capacity is replaced with approximate capacity.}},
	att_copyright_notice={{This version of the work is reprinted here with permission of IEEE for your personal use. Not for redistribution. The definitive version was published in 2013 {, Volume 59}}{{, Issue 11}}{{, 2013-11-01}}
	author={Vaneet Aggarwal and Achaleshwar Sahai and Melda Yuksel and Ashutosh Sabharwal},
	institution={{IEEE Trans. Inf. Th.}},
	title={{Capacity of All Nine Models of Channel Output Feedback for the Two-user Interference Channel}},