Relay channel with private messages

The relay channel with private messages (RCPM) is a generalized relay channel model where in addition to the traditional communication from source to destination (assisted by relay), the source has a private message for the relay, and the relay has a private message for the destination. This paper develops coding strategies for this channel based on decode-and-forward and compress-and-forward schemes. Achievable rate regions as well as outer bounds on the capacity region are obtained for the discrete memoryless relay channel with private messages. Then, the Gaussian versions of this channel are studied and achievable rate regions are characterized. Numerical results are provided that give insights into the trade-offs between private messaging and relayed messaging in this hybrid three-node network. Index Terms--Channel capacity, channel coding, relay channels, wireless networks.