Broadcast strategies for the fading relay channel

Broadcast strategy is an encoding technique that enables the reliably decoded rate to adapt to the actual channel state. This can be achieved if the transmitted signal is composed of superimposed information for different fading levels. We apply the broadcast strategy to fading relay channels. The source encodes its information to two levels, the first one is decoded if the channel state is "bad", and, if the channel state is "good", the superimposed information is decoded after the first one. This approach allows the decoding of some partial information at both the relay and the destination, increasing the overall throughput of the system compared to amplify-and-forward (AF) and modified decode-and-forward (MDF), while resulting in two levels of diversity. We also argue that the broadcast approach over the relay channel also results in lower overall distortion when the source is also taken into account.