Multicast channel communication with interactive receiver cooperation over orthogonal links

We consider the multicast channel (MC), in which a transmitter broadcasts only a common message to two receivers. In our previous work, we have derived information-theoretic upper and lower bounds and showed that the two-round receiver cooperation (2RC) scheme, in which the receivers interactively perform compress-forward and then decode-forward, improves the MC achievable rate over different schemes from the literature, in the general case of full-duplex bi-directional non-orthogonal cooperation links. In this paper, we concentrate on the orthogonal cooperation to identify the properties of this interactive cooperation. We show that the full-duplexing between the cooperation links is not essential to take advantage of most of the gain offered by the 2RC full-duplex scheme, while the full-duplexing between the MC and the cooperation links brings most of the gain.