Capacity Theorems for Cooperative Relay Broadcast Channels

The partially cooperative relay broadcast channel (RBC) is studied, where a source transmits to two users and one user also acts as a relay node to assist broadcast communication. The source has common information intended for both users and private information for each user. Inner and outer bounds on the capacity region are derived for discrete memoryless partially cooperative RRCs with degraded message sets, semideterministic partially cooperative RRCs and orthogonal partially cooperative RRCs. The inner and outer bound are shown to match for the later two channels, and hence the capacity regions are established. Furthermore, when the relay function is disabled, the inner and outer bounds reduce to potentially new bounds on the capacity region of broadcast channels.