A multi-hop broadcast protocol design for emergency warning notification in highway VANETs

Abstract

Multi-hop broadcast transmission is used in vehicular ad hoc networks (VANETs) to alert all vehicles within a geographical area of an emergency situation. However, the successful dissemination of multi-hop warning messages beyond the transmission range of a vehicle faces three major issues: (i) the broadcast storm, (ii) the severe interference with the existing periodic single-hop safety messages, and (iii) the hidden nodes. In this paper, we propose an efficient time-slotted multi-hop broadcast protocol that significantly reduces the number of required transmissions, while ensuring a timely and successful delivery of the warning messages. To alleviate the broadcast storm problem, we select only a subset of vehicles on the road to serve as the potential relay nodes. Each of these 'segment leaders' is responsible for forwarding the warning messages arrived in its own road segment. To avoid interfering with the safety messages transmitted periodically, we propose to allocate separate time slots for the warning messages. We also devise a signaling mechanism that ensures the reliable delivery of these multi-hop messages. Simulation results confirm that the developed protocol substantially outperforms existing schemes in terms of the number of required multi-hop transmissions and the dissemination delay. At the same time, the proposed solution maintains a high reception rate and low end-to-end delay for the single-hop safety messages.

Survey on Simulation for Mobile Ad-Hoc Communication for Disaster Scenarios

“…Recently, a time-slotted multi-hop protocol for disseminating warning messages in VANETs is proposed in [94]. In order to reduce broadcast storm, the protocol selects one vehicle on each road segment to serve as a message forwarder.…”

Collecting road traffic information using vehicular ad hoc networks

“…EDB uses only the distance from the current broadcast node to compute the waiting delay. The combined technique of UMB and SB is proposed in time-slotted multi-hop transmission (TSM) [11]. In TSM, a road segment is divided into sectors and each sector selects the leader node by using information from periodic beacon messages.…”

“…For the number of messages transmitted per hop, a majority of the protocols uses a single broadcast message, with IVG [9] and DRG [10] detecting rebroadcast by overhearing. Two messages per hop consisting of a broadcast message and a unicast reply are used by [16,17], three messages per hop with periodic beacons are used in [11], and four messages per hop are used in [4,5] but all of them are broadcast. Interestingly, all works except [4,6,11,17] evaluate the performance only in a single query session and in a small network environment.…”

Limited area broadcast for warning message delivery over vehicular ad-hoc networks

“…Depending on the method used to choose a broadcast relay, each scheme can be classified into categories such as probabilistic-based broadcast, counter-based broadcast, density-based broadcast, and distance-based broadcast. To learn about other interesting issues related to broadcast forwarding and routing, readers can refer to [21][22][23][24][25][26].…”