Efficient alert messages dissemination in vanets using single-hop distributed protocols

Large efforts are being performed globally by governments, industries and academic institutions for the reduction of high speed road traffic accidents. Alert messages dissemination protocols based on vehicular ad hoc networks (VANETs) have strong potential in the reduction of high speed road traffic accidents. Alert messages can convey early warning messages to the vehicles about an emergency situation ahead. While designing alert messaging protocols in VANETs, it is crucial to satisfy reliable messages reception, high messages reach-ability and low end-to-end communication delays. A number of research work proposed alert messages dissemination protocols using multi-hop propagation with help of intermediate relay nodes. In most works, symmetric range of communication between vehicles is assumed which is not true due to vehicles high mobility, adverse channel effects and radio obstacles. In addition, protocols' performance is evaluated while considering nonrealistic wireless channel conditions and mobility models. This research proposes a novel alert messages dissemination protocol for warning possible endangered vehicles while taking into account asymmetric and adverse radio channel communication scenario. For that, real-time single-hop neighboring nodes information is utilized for computing the next most suitable relay node(s). High messages reception reliability and reach-ability are expected to be achieved while keeping end-to-end communication delays, data traffic redundancy and bandwidth utilization at acceptable levels. With this proposed protocol, the reduction of chain traffic accidents will also be investigated by providing a simulated evaluation of chain crash scenarios. A second protocol is proposed for selection of the node that will perform initial alert messages disseminating in case of multiple cars collision. Performance of the second protocol will be compared with a random initial node selection, where both techniques will be evaluated w.r.t. their effects in improving overall reliability, reach-ability and timeliness of an alert messaging system.

I Introduction

Some of the immediate effects that take place in road traffic accidents include properties damage, injuries and deaths. Due to road accidents, over 1.2 million people die per year, i.e. more than 3000 per day, and as high as 50 million others suffer non-fatal injuries [1]. Road traffic injuries are one of the leading causes of death around the world ranked as the top ninth cause of death in year 2004, and if no immediate action is taken, it is predicted that road traffic injuries would become the top fifth cause of death by 2030 [1], [2]. Road accidents have significant impacts on the economics of many countries, especially at low and middle-income countries. An estimated global loss is US$518 billion and costs governments from 1 % to 3% of their gross national product [3]. According to the Decade of Action for Road Safety 2011–2020, a global plan is drawn for the reduction of road traffic injuries and deaths. If the defined ambitious goals are achieved, approximately 5 million lives, 50 million serious injuries and an amount of US$ 5 trillion could saved over this decade [4].