Deploying an Efficient Safety System for VANET
Authors: Ghassan Samara, Mohammad Rasmi
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The rapid development of wireless communication networks in recent years has made vehicle to vehicle (V2V) and vehicle to infrastructure (V2I) communications possible in mobile ad hoc networks (MANETs). It has also led to the development of a new technology called vehicular ad hoc network (VANET), which aims to achieve road safety, infotainment, and a comfortable driving experience. It can support safety systems designed to avoid road accidents in two ways: 1) periodic transmissions (beacon) from all vehicles that inform neighbors about their current status, and 2) dissemination of emergency messages to warn other vehicles to avoid the danger.
The intent of the research is to propose an efficient safety system for VANET by designing communication protocols and techniques to provide the means for successful transmission of safety-related information. Therefore, three protocols based on power control, contention, and position-based mechanisms are proposed to shape data traffic, such that messages are received with high probability and reliability where they are relevant.
First, a method Coded Repetition Neighbor Table (CRNT) is proposed in , which aims to increase the network awareness to enable the network vehicles to know about current network situations and detect other vehicle movements. Second, a method called Particle swarm optimization Contention Based Broadcast (PCBB) is proposed in  for fast and effective dissemination of emergency messages within a geographical area to distribute the emergency message. Third, a method called Particle swarm optimization Beacon Power Control (PBPC) is proposed in , which aims to decrease the packet collision resulting from periodic messages leading to the control of the load on the channel while ensuring a high probability of message reception within the safety distance of the sender vehicle.
Using the latest version of Matlab simulator, the merits of all the approaches, as well as of their synergies are demonstrated. Simulation results show that PBPC is capable of improving the reception rates of beacon messages and increasing the probability of reception of emergency messages over a wide range of distances between sender and receivers. PCBB enhances the delivery of the emergency information to all nodes located in a geographical area by more than 70%. Furthermore, it enables the emergency message to reach greater distances, thus benefiting the incoming vehicles receiving the important information. When PCBB is used in combination with CRNT and PBPC, the dissemination efficiency and delay are considerably improved. Finally, PBPC is capable of improving the channel performance by controlling the channel load resulting from the beacon messages, reducing packet collision by 50%.
Keywords-VANET; Safety System; PBPC; CRNT; PCBB.