Infocast: A New Paradigm for Collaborative Content Distribution from Roadside Units to Vehicular Networks Using Rateless Codes

摘要

In this paper, we address the problem of distributing a large amount of bulkdata to a sparse vehicular network from roadside infostations, using efficientvehicle-to-vehicle collaboration. Due to the highly dynamic nature of theunderlying vehicular network topology, we depart from architectures requiringcentralized coordination, reliable MAC scheduling, or global network stateknowledge, and instead adopt a distributed paradigm with simple protocols. Inother words, we investigate the problem of reliable dissemination from multiplesources when each node in the network shares a limited amount of its resourcesfor cooperating with others. By using \emph{rateless} coding at the Road SideUnit (RSU) and using vehicles as data carriers, we describe an efficient way toachieve reliable dissemination to all nodes (even disconnected clusters in thenetwork). In the nutshell, we explore vehicles as mobile storage devices. Wethen develop a method to keep the density of the rateless codes packets as afunction of distance from the RSU at the desired level set for the targetdecoding distance. We investigate various tradeoffs involving buffer size,maximum capacity, and the mobility parameter of the vehicles.