Coding for Channels with Rate-Limited Side Information at the Decoder

In this work coding for channel with partial state information at the decoder is studied. Specifically, the model under consideration assumes that the encoder is provided with full channel state information in a non causal manner, and the decoder is provided with partial state knowledge, quantified by a rate-limit. Coding of side information intended for the channel decoder is a Wyner-Ziv like problem, since the channel output depends statistically on the state, thus serving as side information in retrieving the encoded state. Therefore, coding for such a channel involves the simultaneous solution of a Wyner-Ziv problem and a related Gel´fand-Pinsker problem. A single letter characterization of the capacity of this channel is developed, that involves two rate constraints, in the form of Wyner-Ziv and Gel´fand-Pinsker formulas. Applications to watermarking problems are suggested.