File Distribution Algorithm from Multiple Road Side Units in Vehicular Networks

Abstract

In this paper we propose an algorithm for distributing files among moving vehicles through multiple Road Side Units (RSUs). It is assumed that the RSUs are connected and are under the management of a central administration. Thus all RSUs have all the files. Our approach includes two scheduling algorithms: intra-RSU and inter-RSU. The former handles broadcast scheduling of files inside each RSUs coverage area and the latter handles resumable broadcasts from other RSUs. Therefore, it is possible to resume downloading file(s) from other RSUs when the file(s) can not be downloaded completely from a RSU. Furthermore, all files are encoded by means of Fountain Coding techniques meaning that all packets have the same value and there is no need of receiving packets in-order. Consequently, we are able to distribute files with a low overhead and without need of reliable and ACK-based transport protocols such as TCP. Using extensive simulation study we have evaluated the effect of using fountain coding, vehicles’ speed, file size and number of RSUs on the performance of the proposed algorithm.