Truncate-and-Forward: A New Coding Strategy for the General Relay Channel

In this work we focus on the general relay channel. We present a new coding strategy that yields a rate increase over the point-to-point rate for any channel conditions without the use of auxiliary random variables. Specifically, even when Cover & El-Gamal’s decode-and-forward or estimate-and-forward strategies do not exceed the point-to-point rate, our method results in a rate to the destination that is greater than that rate. We then consider the cooperative broadcast scenario with a single common message and show how the new relaying strategy can be used to derive a multi-step conference that achieves the full cooperation rate bound for conference capacities which are less than the Slepian-Wolf condition. This simple method can be extended to other network scenarios to improve results for the case where the relay is very noisy.