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Performance Evaluation of Dissemination Schemes for Coded Packets in Heterogeneous Sparse Ad Hoc Networks
M. Chuah, P. Yang, S. Roy and Bo Sheng

Mobile nodes in some challenging network scenarios suffer from intermittent connectivity and frequent partitions e.g. battlefield and disaster recovery scenarios. Disruption Tolerant Network (DTN) technologies are designed to enable nodes in such environments to communicate with one another. Recently, network coding schemes for DTN have been proposed. However, these schemes work well only in scenarios with homogeneous mobility models. In this paper, we first describe two dissemination schemes for source coded packets: (a) a network coding with binary spread (NCBS) scheme that allows a node to spread coded packets to any node it encounters, (b) an efficient context-aware network coding (CANCO) scheme that allows a node to spread coded packets to some nodes based on delivery predictability and a friendliness metric. Then, we present analytical models we develop for evaluating the performance of both NCBS and CANCO schemes. Next, we conduct simulation studies to compare the NCBS, CANCO schemes with the erasure coding and a MORE-like scheme designed by other researchers using more realistic mobility models. Our simulation studies show that for DTNs, the CANCO scheme achieves higher delivery ratio than the existing published network coding schemes in networks where nodes move according to non-homogeneous mobility models. Specifically, our CANCO scheme delivers 300% more messages with higher data efficiency than a MORE-like scheme because our scheme does not suffer from the stop-and-wait feature in the MORE-like protocol.

Keywords: Network coding, disruption tolerant networks, performance evaluation

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