Performance comparison of retransmission mechanisms for multi-hop relay networks

Relay networking is an appealing option for operators to solve coverage issues and to improve performance without a need to deploy more complex macro sites. In this paper we look at several options for re-transmission mechanisms that are already adopted in wireless standards, such as 3GPP LTE-Advanced and IEEE 802.16. In particular, we consider a hop-by-hop HARQ operation without any ARQ on top of it, and also with ARQ working in the end-to-end and hop-by-hop modes. We run extensive simulations for the aforementioned configurations and present our results indicating that HARQ should be ideally complemented by the ARQ mechanism. As for the exact ARQ mode, the hop-by-hop ARQ provides better performance that however comes at its own implementation cost.