Reliable Multicasting Based on Air Caching for Flat Hierarchy Networks

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The evolution of satellite networks in the commercial and military world has pushed the research community towards the solution of important problems related to this kind of network, which are characterized from the lack of physical hierarchy. One of those important problems is how to design an efficient reliable multicasting protocol for one-hop (flat) networks where the link may present characteristics like high propagation delay and high BER. The existing reliable multicasting protocols are inefficient when applied to flat networks, since those are based on intermediate receivers and local recovery techniques.

We introduce the Air Cache, which serves as a fast access memory that is realized on the air and contains packets for the recovery of corrupted or erroneous data packets at the receivers.

In this thesis we present two classes of reliable multicasting protocols, which are based on the combination of FEC and ARQ with air caching. The non-adaptive class of protocols (UDPAC, RDPAC, PPAC) is characterized by the static nature of the Air Cache in term of size and content and the second class of protocols (ACDAC, ASPAC, HADAC) is characterized by the dynamic nature of the Air Cache. The objective is to achieve better performance than the existing reliable multicasting protocols in flat hierarchy networks.

We evaluate the proposed protocols in terms of the delay, robustness, scalability and the hardware requirements that they pose. The results that we collected prove the effectiveness of air caching when it is combined with traditional techniques like FEC and ARQ.