Emergency message dissemination (EMD) in vehicular ad hoc network (VANET) becomes a hot topic due to the ever increasing concern on the road safety. When encountering unusual situations, emergency messages should be disseminated quickly to as many vehicles as possible in order to avoid any potential accidents. For this application, two basic requirements are low latency and high reliability [23]. In urban area, EMD application can be applied with roadside devices (e.g. using a base station to broadcast). But in the areas that infrastructures are difficult to be deployed and maintained, multi-hop broadcast is the main technique used in this application. However, multi-hop broadcast scheme leads to broadcast storm problem in dense traffic. Several approaches have been proposed to solve this problem. They can be classified as distanced-based, cluster-based, and probability-based approaches. In distance-based approaches, vehicles that farther from the source vehicle are selected as relay nodes in order to achieve a better cover area. In cluster-based approaches, each cluster has a cluster head which is used as the relay node. The cluster is self-organized and the cluster head is selected according to information such as vehicle's speed, direction, location, and antenna height. Both distance-based and cluster-based approaches require the maintenance of the network topology. For probability-based approaches, vehicles don't care about the network topology or their neighbors’ information. A vehicle decides its probability to broadcast based on the information contained in the received packet. This thesis analyzes the existing protocols and points out the issues of the existing approaches. For the issues, we present a novel probability-based broadcast scheme that can inhibit broadcast storm, decrease the end-to-end delay, and guarantee that the emergency messages are delivered to most of the vehicles. The rest of the thesis is structured as follows. In chapter 1 we introduce the concept of VANET and remaining issues of the existing methods for EMD. The research problem in this work is defined and several related works are reviewed. In chapter 2, we analyze the probability-based protocol and proposed our protocol in detail. The typical probability-based protocol [13] uses a linear function to determine whether or not a vehicle should broadcast. However, it doesn't perform well in dense traffic in term of end-to-end delay. Our protocol uses an exponent function instead of the linear function in probability-based approaches. The simulation results show that our protocol can shorten the end-to-end delay in dense traffic without impacting the reliability. In chapter 3, we present the network model and simulation results, including the tools used for the simulation. Especially, key parameters of the proposed protocol are discussed. The simulation results as well as network performance analysis are presented in chapter 4. In chapter 5, we conclude this work. The remaining problems and future work of the proposed protocol are summarized in this chapter. / A Thesis submitted to the Department of Electrical and Computer Engineering in partial fulfillment of the requirements for the degree of Master of Science. / Summer Semester 2016. / May 18, 2016. / Emergency Message Dissemination, Probabiliy, VANET / Includes bibliographical references. / Ming Yu, Professor Directing Thesis; Bruce A. Harvey, Committee Member; Bing W. Kwan, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_366145 |
| Contributors | Zhang, Chenqi (authoraut), Yu, Ming (professor directing thesis), Harvey, Bruce A., 1961- (committee member), Kwan, Bing Woon, 1953- (committee member), Florida State University (degree granting institution), College of Arts and Sciences (degree granting college), Department of Electrical and Computer Engineering (degree granting department) |
| Publisher | Florida State University, Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource (67 pages), computer, application/pdf |
| Rights | This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them. |
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