Skip to Main Content
We propose two novel communication protocols for the quasi-static coherent fading relay channel and analyze them under the diversity-multiplexing tradeoff framework. Both these protocols satisfy the half-duplex constraint and fall under the class of decode and forward (DF) protocols, wherein the relay node attempts to decode the source signal and if successful transmits the re-encoded signal. Our first protocol is a static DF protocol where the relay waits for a fixed (channel independent) duration before attempting to decode. We show that it achieves a tradeoff curve that uniformly improves upon those of the previous best known static half-duplex protocols, which are the NAF protocol and the STC3 protocol. Our second protocol is a dynamic DF protocol where the relay waits for a dynamic (channel dependent) duration before attempting to decode and it is shown to achieve a tradeoff curve that uniformly improves upon those of all previously proposed half-duplex protocols, including the dynamic DF protocol.