Coding for the bidirectional broadcast channel with random states known at the encoder

In this work, coding for a discrete memoryless broadcast channel with random states and two receivers is studied. Each receiver knows one of the two information sources at the sender and wants to know the other one. Since it is assumed that the sender knows the channel state sequence non-causally, an achievable rate region using Gel´fand-Pinsker-coding is derived. Further, a simple outer bound to the capacity region as well as convexity and cardinality properties regarding the input probability distributions are discussed. The problem is motivated by the application of bidirectional communication between two terminals in a cellular system.