A sequential transmission scheme for unifilar
finite-state channels with feedback based on
Electrical Engineering and Computer Science Department
University of Michigan
Ann Arbor, MI, 48109-2122
The capacity of unifilar finite-state channels with feedback has been recently derived in the form
of a single-letter expression and it has been evaluated analytically for a number of channels of interest,
such as the trapdoor channel and the Ising channel with feedback. In this paper, we investigate capacity-
achieving transmission schemes for this class of channels. These schemes are inspired by the posterior
matching scheme (PMS) introduced for memoryless channels with feedback. The transmission scheme
is proven to achieve the channel capacity.
Communication in the presence of feedback has been a long studied problem which dates back
to Shannon's early work , showing that feedback cannot increase the capacity of memoryless
channels. For channels with memory, however, feedback may increase the capacity.