Cooperative relay cognitive interference channels with causal channel state information

The cooperative relay cognitive interference channel (RCIC) is a four-node network with two source nodes (primary source and cognitive source) and two destination nodes, in which sources try to communicate at certain rates with their corresponding destinations simultaneously through a common medium and each destination can act as a relay to assist the other one. In this paper, we study partially and fully cooperative state-dependent relay cognitive interference channels (RCICs) with perfect causal channel state information (CSI). For each of these channels, we investigate three different cases. For the first case, perfect causal CSI is available at both the source and relay nodes; for the second case, perfect causal CSI is only known to the relay nodes; and for the third case, perfect causal CSI is only available at the cognitive source. We obtain the capacity region of each case, for a degraded version of the channel. Our results include the previously obtained results for the degraded relay, broadcast and relay broadcast channels with perfect causal CSI, as special cases.