Dual-Hop Adaptive Packet Transmission with Regenerative Relaying for Wireless TDD Systems

We consider the design and performance analysis of adaptive modulation and coding (AMC) applied to regenerative dual-hop transmission systems, where a source node communicates with a corresponding destination node only indirectly via an intermediate relay station operating in the well-known decode-and-forward mode. Specifically, we consider the general case where the AMC over both hops is performed independently of each other. As such, a buffer is required at the relay station to buffer certain data packets received from the source node before they can be forwarded to the actual destination. The proposed scheme is especially suitable for systems operating in time division duplex (TDD) mode, where channel state information is readily available at the transmitter-side. We analyze the performance of our approach based on a finite-state Markov chain model of our system and we derive exact analytical closed-form expressions for a variety of different performance measures, which are illustrated for various cases by means of selected numerical results.