Broadcast channels with cooperating receivers: a downlink for the sensor reachback problem

This paper describes the problem of communicating over broadcast channels (BCs) with partially cooperating receivers. In our setup receivers are able to exchange messages over conference links, prior to making their decisions. This problem comes up naturally in a sensor networking application, where a transmitter external to the sensor network wants to download data into the network to, e.g., configure the sensor array. We find the capacity region for the case where the BC is degraded. This region is a strict enlargement of the classical region for the degraded BC without cooperation in [T.M. Cover,(1998)].