Duality between channel capacity and rate distortion with two-sided state information

We show that the duality between channel capacity and data compression is retained when state information is available to the sender, to the receiver, to both, or to neither. We present a unified theory for eight special cases of channel capacity and rate distortion with state information, which also extends existing results to arbitrary pairs of independent and identically distributed (i.i.d.) correlated state information (S₁, S₂) available at the sender and at the receiver, respectively. In particular, the resulting general formula for channel capacity C = max_p(u,x|s₁) [I(U; S₂, Y) I(U; S₁)] assumes the same form as the generalized Wyner-Ziv (1976) rate distortion function R(D) = min_p(u|x, s₁)p(x&capped;|u, s₂) [I(U; S ₁, X) 1(U; S₂)]