  A partially cooperative relay broadcast channel (RBC) is a three-node network
with one source node and two destination nodes (destinations 1 and 2) where
destination 1 can act as a relay to assist destination 2. Inner and outer
bounds on the capacity region of the discrete memoryless partially cooperative
RBC are obtained. When the relay function is disabled, the inner and outer
bounds reduce to new bounds on the capacity region of broadcast channels. Four
classes of RBCs are studied in detail. For the partially cooperative RBC with
degraded message sets, inner and outer bounds are obtained. For the
semideterministic partially cooperative RBC and the orthogonal partially
cooperative RBC, the capacity regions are established. For the parallel
partially cooperative RBC with unmatched degraded subchannels, the capacity
region is established for the case of degraded message sets. The capacity is
also established when the source node has only a private message for
destination 2, i.e., the channel reduces to a parallel relay channel with
unmatched degraded subchannels.
