BEAM-HW: Bandwidth Efficient Acknowledgement based Multicast Protocol for High_Way: A Novel Protocol for Emergency Warning in VANET

Objective: The main objective of this paper is to design a highway road accident prevention system to proactively alert vehicles about a possible accident with an Emergency Warning Message (EWM). Methods/Analysis: A Bandwidth Efficient Acknowledgement based Multicast protocol for High-Way (BEAM-HW) scenario is proposed in this paper. The BEAM-HW protocol attempts to multicast EWM only to the vehicles that are endangered or intended to receive and it has an acknowledgement mechanism to ensure reception. Network Simulator-2 is used to compare and validate the performance of BEAM-HW protocol with Bandwidth Efficient Acknowledgement based Multicast (BEAM) protocol, which is developed for sub-urban scenario in Vehicular Adhoc Network (VANET). Findings: In BEAM-HW, once an emergency situation is predicted, the Road Side Unit (RSU) performs the following tasks, 1. Forms a multicast group, 2. Generates a EWM, 3. Multicasts the EWM to the vehicles in the multicast group and 4. Ensures the EWM reception using acknowledgement mechanism. It is evident from the simulation experiment that BEAM-HW protocol outperforms BEAM in EWM notification and end-to-end delay. During simulation the following observations are made: BEAM-HW notifies EWM to 95.625 percent of vehicles and this is 8.25 percent higher than BEAM. The end-to-end delay in BEAM-HW for a vehicle density of 160 vehicles is 47 ms, which is comparatively better than BEAM. The performance of BEAM-HW and BEAM are closer in in-network message transaction, reception rate and network processing overhead. Novelty/Improvement: The BEAM-HW helps to reduce: 1. Number of highway road traffic accidents, 2. Death and injury rate, 3. In-network message transactions. It also assures EWM delivery and uses the bandwidth efficiently.