Opportunistic ARQ With Bidirectional Overhearing for Reliable Multihop Underwater Networking
Source: Institute for Infocomm Research
As reliable data delivery over a long-range single-hop underwater acoustic link is considerably challenging due to severe channel impairments, multi-hop data transmission schemes over one or more relay nodes have been proposed. In this paper, the authors propose a data delivery scheme using a fully-opportunistic ARQ that employs bidirectional overhearing, whereby nodes leverage on the broadcast nature of acoustic channels and their spatial and temporal variance to overhear data packets from all upstream (nearer to source) nodes to speed up data delivery and data & acknowledgement packets from all downstream (nearer to sink) nodes as implicit acknowledgements. The cross-layer scheme uses implicit acknowledgements to purge duplicates at both data-link and network layer.