  We consider the problem of stabilizing an unstable plant driven by bounded
noise over a digital noisy communication link, a scenario at the heart of
networked control. To stabilize such a plant, one needs real-time encoding and
decoding with an error probability profile that decays exponentially with the
decoding delay. The works of Schulman and Sahai over the past two decades have
developed the notions of tree codes and anytime capacity, and provided the
theoretical framework for studying such problems. Nonetheless, there has been
little practical progress in this area due to the absence of explicit
constructions of tree codes with efficient encoding and decoding algorithms.
Recently, linear time-invariant tree codes were proposed to achieve the desired
result under maximum-likelihood decoding. In this work, we take one more step
towards practicality, by showing that these codes can be efficiently decoded
using sequential decoding algorithms, up to some loss in performance (and with
some practical complexity caveats). We supplement our theoretical results with
numerical simulations that demonstrate the effectiveness of the decoder in a
control system setting.
