Combined Hybrid ARQ and Link Adaptation for Coded Cooperation in Block-Fading Channels
Cooperative Hybrid ARQ (HARQ) protocols have been widely studied in recent years and they were shown to provide higher efficiency than cooperative protocols. This paper proposes a joint design within which the HARQ protocol collaborates with the link adaptation functionality and the cooperative transmission scheme in order to adapt the behavior of the HARQ protocol to the QoS requirements of the supported services. As performance metrics of the HARQ protocol, the authors use the expected number of retransmissions and the expected spectral efficiency. The paper also studies the influence of the protocol parameters upon the performance provided.