دانلود رایگان ترجمه مقاله طرح انتخاب گره های رله سازگار برای پخش چند هاپ در دانت (نشریه الزویر 2016)

طرح انتخاب گره های رله سازگار با پخش چندهاپی در VANET ها

An adaptive relay nodes selection scheme for multi-hop broadcast in VANETs

Abstract

Vehicular ad hoc networks (VANETs) have potential applications for improving on-road driving experiences including preemptive road safety measures and provision for infotainment services. This paper proposes a Bi-directional Stable Communication (BDSC) relay nodes selection scheme designed for multi-hop broadcasting protocols over a platoon of vehicles. Relay nodes selection is based on quantitative representation of link qualities for single-hop neighboring nodes by using a proposed link quality estimation algorithm. The BDSC scheme aims to improve packet delivery ratio while maintaining low end-to-end communication delays over a densely populated network with nodes distributed over a large coverage area. To achieve this, the proposed scheme attempts to adaptively balance between the estimated link qualities and the distance between the source broadcaster and the potential forwarders when selecting the next hop nodes for relaying the broadcast messages. Our results from extensive simulation analysis reveal that the proposed BDSC scheme outperforms existing multi-hop broadcasting schemes in terms of packet delivery ratio when evaluated over a densely populated VANETs.

1 Introduction

Many academic as well as industrial experts expect vehicular ad hoc networks (VANETs) to become the de-facto enabling technology for communication among vehicles on the road [1–5]. The scale of research projects, road tests and government investments in VANETs has intensified over the past few years [6–10]. This has been fuelled by the fact that VANETs can play a key role in improving traffic safety and efficiency by enhancing drivers’ awareness of immediate and far distant traffic situations [11–13]. In addition, a variety of comfort and infotainment services is plausible to deploy over VANETs to further enhance on-road experience [13–16].

Large physical areas can be covered in a platoon of communication technology-enabled vehicles using a multi-hop propagation scheme, where assistance from intermediate relay nodes is used for forwarding messages to their final destination. In addition, multi-hop propagation provides a controlled broadcasting over a shared wireless medium instead of using a high power long transmission range configurations, which in-turn expands the collision domain of messages [17,18]. A proper selection of relay nodes is crucial in the design of multi-hop broadcast messaging protocols which highly governs the delivery ratio of the broadcasted mes- sages, especially over densely populated networks [12,19–21]. Conversely, a poor selection of relay nodes could lead to the drop of message reception rates, hence significantly limiting the delivery of messages over far distanced nodes. For the case of critical-innature safety alert messages, reliable and timely reception of these messages is a prime design objective when developing VANETsbased multi-hop safety messaging protocols [22,23]. In accordance with the safety messaging design requirements, a proper selection of relay nodes in multi-hop alert messages broadcast is an important aspect that requires in-depth investigation.

This paper introduces a new Bi-Directional Stable Communication (BDSC) relay nodes selection scheme for multi-hop messages broadcasting which can be used for different broadcast based applications in VANETs, such as safety alert messaging, route discovery and on-road information advertisement. The proposed scheme is incorporated with a sender-oriented messaging protocol in which the potential relay nodes are explicitly selected at the sender side. The BDSC scheme takes into consideration the quantitative estimations of link qualities for the forward links between each pair of nodes. The proposed scheme aims to improve multihop packet delivery ratio over densely populated network and at far distanced nodes. To reduce the loss of messages at the relays, the proposed scheme aims to adaptively improve the relay selection process by focusing not only on the distance from source but also on the link quality ratio.

The rest of the paper is organized as follows. Section 2 provides an overview on broadcasting techniques in VANETs and also discusses the relevant research work. Section 3 describes the multi-hop broadcasting scheme using the proposed BDSC scheme along with the link quality estimation and link selection criteria algorithms. Section 4 describes the simulation scenario over a varying speed mobility profile. Section 5 presents and analyzes the obtained simulation results and Section 6 concludes the work alongside with suggestions for further system performance improvement.