Delay Model of Single-Relay Cooperative ARQ Protocols in Slotted Radio Networks with Non-Instantaneous Feedback and Poisson Frame Arrivals

In cooperative ARQ protocols, data frame retransmissions may be performed by a neighboring node (the relay) that has successfully overheard the source´s frame transmission. One advantage is the diversity provided by the relay. The three-way (source, destination, relay) frame exchange sequence required in the cooperative ARQ protocols may however introduce extra latency when compared to non-cooperative ARQ protocols. To take advantage of cooperative ARQ protocols, it is then necessary to resort to selective repeat solutions. The focus of the paper is to derive a delay model for cooperative selective repeat ARQ protocols in slotted radio networks. The derived analytical model quantifies, with closed formulas, the queueing and transmission delay experienced by Poisson arriving data frames, whose retransmissions are performed by a single relay.