Bernd Bandemer, Abbas El Gamal, and Young-Han Kim
IEEE Transactions on Information Theory, vol. 61, no. 12, pp. 6536–6549, December 2015.
Preliminary results appeared in Proceedings of the 50th Annual Allerton Conference on Communication, Control, and Computing, pp. 9–16, Monticello, Illinois, October 2012.
The optimal rate region for interference networks is characterized when encoding is restricted to random code ensembles with superposition coding and time sharing. A simple simultaneous nonunique decoding rule, under which each receiver decodes for the intended message as well as the interfering messages, is shown to achieve this optimal rate region regardless of the relative strengths of signal, interference, and noise. This result implies that the Han-Kobayashi bound, the best known inner bound on the capacity region of the two-user pair interference channel, cannot be improved merely by using the optimal maximum likelihood decoder.