Using zero-rate feedback on binary additive channels with individual noise sequences

Krishnan Eswaran, Anand D. Sarwate, Anant Sahai, Michael Gastpar

Abstract: Recently, Shayevitz and Feeler introduced an individual sequence formulation of channel coding under model uncertainty and an elegant coding strategy that adapts Horstein's scheme to this setting to achieve the empirical capacity of the channel. Their scheme requires both full-rate output feedback and common randomness. We present a strategy in the style of Hybrid ARQ that requires no output feedback by using common randomness and zero-rate active feedback. This strategy still asymptotically achieves the empirical capacity.