Reliable multicast for flat hierarchy networks based on adaptive air caching

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. One of those important problems is how to design an efficient reliable multicast protocol in a network where there is no hierarchy involved, and the link presents characteristics like high propagation delay and high BER. The existing reliable multicast protocols cannot be applied in the case of flat hierarchy networks, since those are based on intermediate receivers and local recovery techniques. So, we introduce the air caching technique, 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 paper we present some of the protocols that we designed and are based on air caching combined with FEC and ARQ. In the past we have presented protocols that are based on those techniques but the characteristics of the air cache were constant. In this paper we propose RM protocols, which are based on adaptive air caching, where the size and/or content of the air cache change dynamically based on feedback information. Our goal is to improve the delay and/or bandwidth usage characteristics of the nonadaptive air cache RM protocols.