Cooperative Relaying with State Available at the Relay Only

We consider a full-duplex state-dependent relay channel with state non-causally available at only the relay. In the framework of cooperative wireless networks, some specific terminals can be equipped with cognition capabilities, i.e, the relay in our model. In the discrete memoryless (DM) case, we obtain inner and outer bounds on the capacity. The inner bound is obtained by a coding scheme at the relay that uses codeword splitting, Gel’fand-Pinsker coding, and decode-andforward scheme. The outer bound on the capacity is better than that obtained by assuming the availability of state at the source, the destination, and the relay. For the Gaussian case, we also obtain inner and outer bounds on the capacity. The inner bound, obtained by a coding scheme based on combination of codeword splitting and Generalized dirty paper coding, is tight in several cases if the channel is physically degraded. The outer bound is also better than that obtained by assuming the channel state available at the source, the relay, and the destination.