Hybrid alternative Receiver-Sender approach with a colored DR/BDR mechanism for the broadcast of safety messages in VANETs

Abstract

Multi-hop broadcasting represents the key technique to disseminate warning messages in vehicular networks. Its core problem is how to minimise the number of redundantly received messages while maintaining good latency and reachability that are hard to achieve simultaneously owing to the vehicles mobility and the lossy wireless channel. The proposed Sender-Oriented approaches delay the rebroadcast and cannot ensure reliability. Receiver-oriented ones, which are most suitable for safety applications, have to benefit in an efficient way from the exchanged IEEE802.11P safety beacons. In this paper, we propose an alternative Receiver-Sender approach that combines advantages of the two existing approaches to ensure low latency and high reliability. To overcome the unreliability and broadcast overhead generated by periodic rebroadcasts and multiple relay schemes, we introduce a designated relay (DR)/backup designated relay (BDR) mechanism where the BDR has to replace the DR when detecting its failure in informing concerned vehicles based on exchanged coloured beacons. Simulations show that combining the two approaches with the DR/BDR mechanism has a better performance than using each approach separately.