CluRMA: A cluster-based RSU-enabled message aggregation scheme for vehicular ad hoc networks

Abstract

The fundamental goal of Vehicular Ad hoc NETworks (VANETs) is to facilitate safe driving by sending safety/warning messages to vehicles as well as to exchange non-safety/infotainment messages among vehicles. Flooding is a common broadcasting technique and it is mainly used for disseminating safety/non-safety messages. However, flooding causes broadcast storm problem which is the most challenging issue in VANETs. In a dense vehicular network, high message generation rate demanding more transmissions could further increases the effects of the broadcast storm problem. In this context, message aggregation schemes could offer a great relief. In this paper, we propose a cluster based RSU enabled message aggregation protocol (CluRMA) which applies two levels of message aggregation — local aggregation at the cluster heads and global aggregation at the Road Side Unit (RSU). Before message aggregation process is performed, we make use of cosine distance for similarity checking between the messages for eliminating the duplicates. Then the syntactic aggregation is accomplished by employing message compression techniques — Adaptive Huffman Compression technique for safety messages, and Arithmetic Coding Technique for non-safety messages. The competence of the proposed scheme has been rigorously analyzed and compared with the existing ones regarding several metrics including delay, packet delivery ratio, collision rate, redundancy rate and overload.