基于城市道路实时信息的VANET动态路由协议

文章提出动态路由算法DRDC(基于城市道路实时信息的VANET动态路由算法),该路由算法利用实时车流信息来动态创建基于道路的路径,并采用动态路由更新策略和基于下一跳速度矢量选择最优路径来降低端到端时延。仿真结果表明,与现有的VANET路由算法相比,该算法能有效改善分组的传输效率,降低端到端的传输时延。     

城市场景下基于速度信息的VANET路由协议的改进

车载自组网络(Vehicular Ad Hoc Networks,VANET)是指道路上由车辆搭载的无线通信装置构成的一种特殊的多跳无线移动自组织网络。VANET在实现多种智能交通方面应用的同时,还能满足用户在乘车时的娱乐等舒适性的需求,近些年来已成为无线自组网络研究的新热点。总结了近些年来出现的主要VANET路由协议的核心路由机制及其优缺点,并分析了各种技术对路由协议性能的影响。其后给出了一种基于速度信息的VANET路由协议改进方法,并通过实验验证了将改进方法与GPSR协议结合可以提高路由路径的稳定性,减少了端到端的平均时延,降低了VANET网络中拓扑的高动态性对路由协议性能的影响。     

车载自组织网络路由协议研究进展与比较

车载自组织网络( VANET)是一种新型移动自组织网络。作为移动无线网络的热点研究领域,车载自组织网络的间歇连通性使路由设计充满挑战。首先阐述了车载自组织网络的主要特征和应用;在对车载网络路由协议进行分类的基础上,详细描述了一批有代表性的路由协议;对比和总结了各类路由协议的特点,并提出相关研究建议,可为车载网络路由协议研究提供一定的参考价值。     

车载自组织网络路由协议研究进展与比较

车载自组织网络（VANET）是一种新型移动自组织网络。作为移动无线网络的热点研究领域,车载自组织网络的间歇连通性使路由设计充满挑战。首先阐述了车载自组织网络的主要特征和应用;在对车载网络路由协议进行分类的基础上,详细描述了一批有代表性的路由协议;对比和总结了各类路由协议的特点,并提出相关研究建议,可为车载网络路由协议研究提供一定的参考价值。     

高速预警信息传输下的VANET路由协议研究

针对当前高速公路信息预警的需求及传统信息传输路由协议存在的传输时延大、网络性能差等问题,提出一种基于实时丢包率估计与最短时延优先的车联网(Vehicular Ad Hoc Network,VANET)路由协议。提出实时丢包率估计算法,从而提高网络传输的准确率;在方向性广播转发路由技术的基础上,从后方行驶的车辆中选择传输时延为最小的节点作为网络信息传输的转播节点,从而协议在保证危险区域内都能够接收到预警信息的前提下减少节点转播的数量。通过NS-3仿真结果表明,该算法可降低传输时延,并提高信息传输的准确率。     

一种基于实时车流密度信息的VANET路由协议

在车载自组网中,路由协议很大程度上决定了整个网络的性能。如何有效的利用车流信息提高传输质量是改善路由性能的一个关键问题。本文基于速度-密度线性模型,提出了一种实时车流密度的路由协议RVDR(Real-time Vehicle Density Routing)。该协议通过与邻居节点交换的速度信息,对相关道路车流密度进行预测,并给出基于车流密度信息的路径选择方法。仿真结果表明,与现有协议相比,RVDR协议在实时性和高效性等性能方面得到改进。     

一种无线自组织网络动态路由协议

介绍了一种基于稀疏树的无线自组织网络动态路由协议,该协议采用了稀疏树路径生成算法来减少路由更新的数据量并减少网络链路的冗余,采用增量更新来降低路由协议开销并降低对传输带宽的占用,支持单向信道,采用快速路径查找算法消除网络拓扑动态变化过程中的环路与无穷计数问题。仿真结果显示它具有收敛快,开销小等特性,能够较好地适应窄带无线通信环境的需要。     

一种基于区域广播的VANET机会路由协议

对VANET网络中现有的路由协议进行了系统的分析和研究,提出了一种基于区域广播的VANET机会路由协议。基于安全消息在网络割裂情况下的传播需求,新协议结合地理信息和机会转发算法,提出了不同于点对点的新的基于区域广播的消息传播模式,以实现安全消息在稀疏车辆环境下的有效传播。理论分析和仿真实验表明,该协议相比传统路由协议具有更优异的网络性能和可靠性。     

车载自组织网络路由协议研究

文章对VANET的研究必要性以及VANET的特性进行分析后,从消息内容、节点属性和拓扑构造三个角度对VANET进行了分析并对三方面的最新研究进行了描述,分析了车载自组织网络路由协议中常使用的实时信息及现有路由协议存在的问题,并给出了VANET进一步的研究方向。     

基于OFDM认知无线电网络的最优路径算法

针对基于正交频分复用的分布式认知无线电网络,在考虑频谱移动特性的同时,为保证认知用户数据传输的可靠性,提出一种最优路径的基于OFDM认知无线电网络路由算法.该算法首先通过建立认知无线电网络的模型计算信道的期望传输时间和信道干扰,结合类似于按需路由的基本流程得到所有可能的路径.最后,根据最小累积期望传输时间和路径平均吞吐量的指标来选择最优路径.仿真的结果表明,OROCR算法可以明显地减少平均端到端时延,大大地提高平均端到端吞吐量.     

ACAR: Adaptive Connectivity Aware Routing for Vehicular Ad Hoc Networks in City Scenarios

Multi-hop vehicle-to-vehicle communication is useful for supporting many vehicular applications that provide drivers with safety and convenience. Developing multi-hop communication in vehicular ad hoc networks (VANET) is a challenging problem due to the rapidly changing topology and frequent network disconnections, which cause failure or inefficiency in traditional ad hoc routing protocols. We propose an adaptive connectivity aware routing (ACAR) protocol that addresses these problems by adaptively selecting an optimal route with the best network transmission quality based on statistical and real-time density data that are gathered through an on-the-fly density collection process. The protocol consists of two parts: 1) select an optimal route, consisting of road segments, with the best estimated transmission quality, and 2) in each road segment of the chosen route, select the most efficient multi-hop path that will improve the delivery ratio and throughput. The optimal route is selected using our transmission quality model that takes into account vehicle densities and traffic light periods to estimate the probability of network connectivity and data delivery ratio for transmitting packets. Our simulation results show that the proposed ACAR protocol outperforms existing VANET routing protocols in terms of data delivery ratio, throughput and data packet delay. Since the proposed model is not constrained by network densities, the ACAR protocol is suitable for both daytime and nighttime city VANET scenarios.     

State-of-Art and Open Issues of Cross-Layer Design and QOS Routing in Internet of Vehicles

VANET (Vehicular Ad Hoc Network) is a significant term in ITS (intelligent transportation systems). VANETs are also mentioned as ITN (intelligent transportation Networks), which are used to enhance road safety in growing technology. The connectivity of nodes is a challenging one because of its high mobility and the sparse network connectivity must be handled properly during its initial deployment of a VANET for avoiding accidents. Quality of service (QoS) in VANET becomes a significant term because of its increasing dare about unique features, like poor link quality, high mobility, and inadequate transporting distance. Routing is the foremost issue in the wireless ad hoc network, which is used to transmit data packets significantly. This paper provides a crucial review of the classification of existing QoS routing protocols, cross-layer design approach and classification, and various performance parameters used in QoS routing protocols. The corresponding cross-layer protocols are overviewed, followed by the major techniques in cross-layer protocol design. Moreover, VANET is presented with many exclusive networking research challenges in precise areas such as security, QoS, mobility, effective channel utilization, and scalability. Finally, the paper concluded by various comparison discussion, issues, and challenges of several routing protocols for VANET. No. of publications over the period from 2010 to 2019 in various scientific sources also showed in this review. This survey provided the technical direction for researchers on routing protocols for VANET using QoS.

     

Road Oriented Traffic Information System for Vehicular Ad hoc Networks

Over the last few years, vehicular ad hoc networks (VANETs) have gained popularity for their interesting applications. To make efficient routing decisions, VANET routing protocols require road traffic density information for which they use density estimation schemes. This paper presents a distributed mechanism for road vehicular density estimation that considers multiple road factors, such as road length and junctions. Extensive simulations are carried out to analyze the effectiveness of the proposed technique. Simulation results suggested that, the proposed technique is more accurate compared to the existing technique. Moreover, it facilitate VANET routing protocols to increase packet delivery ratio and reduce end-to-end delay.     

SDR: A Stable Direction-Based Routing for Vehicular Ad Hoc Networks

A stable and reliable routing mechanism for vehicular ad hoc networks (VANETs) is an important step toward the provision of long data transmission applications, such as file sharing and music download. Traditional mobile ad hoc network (MANET) routing protocols are not suitable for VANET because the mobility model and environment of VANET are different from those of traditional MANET. To solve this problem, we proposed a new stable routing algorithm, called stable directional forward routing. The novelty of the proposed routing protocol is its combining direction broadcast and path duration prediction into ad hoc on-demand distance vector routing protocols, which including: (1) Nodes in VANET are grouped based on the position, only nodes in a given direction range participating in the route discovery process to reduce the frequency of flood requests, (2) Route selection is based on the link duration while not the hops or other metrics to increase the path duration, (3) Route discovery is executed before the path expiration in order to decrease the end to end delay. The performance of the new scheme is evaluated through extensive simulations with Qualnet. Simulation results indicate the benefits of the proposed routing strategy in terms of decreasing routing control packet, reducing the number of link-breakage events, improving the packet delivery ratio and decreasing the end-to-end delay.     

基于局部梯度场的VANET路由研究

车载自组织网络(VANET,Vehicular Ad hoc Network)近几年受到高度关注,同时多跳安全消息路由成为VANET应用的核心问题之一。试图借助梯度场的方法,研究VANET网络安全消息的定向、受限空间及拓扑动态变化条件的传播机制,以达到快速准确地传播安全消息的目的。提出了一种局部梯度场的路由协议(LGFR,Local Gradient Field Routing),并与城市场景下的贪婪边界无状态路由(GPSR,Greedy Perimeter Stateless Routing)和无线自组网按需平面距离矢量路由(AODV,Ad hoc On-DemandDistance Vector Routing)进行了对比。仿真结果表明,LGFR在数据包丢包率、数据包端到端平均时延和全局数据吞吐量方面具有较好的性能。     

基于城市道路的稳定车载网分簇路由策略

由于车载自组网具有节点高速运动、网络拓扑变化快、链路有效时间短等特点,使得传统移动自组网分簇路由协议在车载网中不再适用。基于此,提出了一种新的稳定的分簇路由策略,引入辅簇头的设计理念,并设计了一种高效的岔路口路由策略,通过岔路口二次选择,有效解决岔路口路由冗余问题。通过NS2模拟仿真表明,新的路由策略可有效避免簇结构变化导致的丢包率上升问题,能够以更少的跳数、更低的延时成功传递数据包,具有较好的性能。     

城市环境VANETS下的基于beacon控制的路由方案

车载网络(Vehicular ad hoc networks,VANETs)是一种特殊形式的网络,具有节点高速移动、拓扑频繁的变化的特性。这些特性为消息的传播带来挑战。路由机制是实现消息传递的关键因素。地理位置路由被广泛地应用于VANETS,要求节点周期广播beacon消息。然而,节点周期地广播beacon消息,降低了路由性能,特别是在城市区域,由于节点密集,每个节点均广播beacon消息,恶化了路由性能。为此,针对城市环境,提出基于beacon控制的路由协议RPBC(Routing protocol with beacon control)。在RPBC中,并非每个节点广播beacon消息,而设置有效的机制选择部分节点广播,从而降低了beacon冗余,同时,采用最短路径算法,减少数据传输跳数。仿真结果表明,提出的RBPC在分组投递率、端到端传输时延以及路由开销方面均有较好的性能。     

Routing in Sparse Vehicular Ad Hoc Wireless Networks

A vehicular ad hoc network (VANET) may exhibit a bipolar behavior, i.e., the network can either be fully connected or sparsely connected depending on the time of day or on the market penetration rate of the wireless communication devices. In this paper, we use empirical vehicle traffic data measured on 1-80 freeway in California to develop a comprehensive analytical framework to study the disconnected network phenomenon and its network characteristics. These characteristics shed light on the key routing performance metrics of interest in disconnected VANETs, such as the average time taken to propagate a packet to disconnected nodes (i.e., the re-healing time). Our results show that, depending on the sparsity of vehicles or the market penetration rate of cars using Dedicated Short Range Communication (DSRC) technology, the network re-healing time can vary from a few seconds to several minutes. This suggests that, for vehicular safety applications, a new ad hoc routing protocol will be needed as the conventional ad hoc routing protocols such as Dynamic Source Routing (DSR) and Ad Hoc On-Demand Distance Vector Routing (AODV) will not work with such long re-healing times. In addition, the developed analytical framework and its predictions provide valuable insights into the VANET routing performance in the disconnected network regime.     

Collaboration of Trusted Node and QoS Based Energy Multi Path Routing Protocol for Vehicular Ad Hoc Networks

In the recent past information transmission through the vehicular ad hoc network (VANET) playing a vital role due to increase in accident statistics. There are numerous networking and VANET protocols helpful to control the trust while transmitting the data from source to destination nodes in traffic environment. In spite of many existing protocols for analyzing the trust in the network, the challenge of routing overhead, high energy consumption and malicious attacks issues still continue in the communication. This research introduces the trust collaboration nodes and Quality of Service (QoS) with energy multipath routing protocol for transmitting the information through VANET. Initially, the trusted nodes have been collected for analyzing the neighbouring nodes and the information are transmitted using the proposed QoS based energy efficient multipath routing protocol. During this transmission, the multi path protocol eliminates the intermediate attacks effectively when compared with the other existing protocols. The Proposed protocol maintains the QoS while routing the information from source to destination and further the efficiency has been analyzed through simulation experiments and Montgomery multiplier based Elliptic Curve Cryptography (ECC) will be used in future for better security and privacy.     

Link efficiency and quality of experience aware routing protocol to improve video streaming in urban VANETs

In a vehicular ad‐hoc network (VANET), vehicles can play an essential role in monitoring areas of a smart city by transmitting data or multimedia content of environmental circumstances like disasters or road conditions. Multimedia content communication with quality of experience (QoE) guarantees is a challenging undertaking in an environment such as that of a VANET. Indeed, a VANET is characterized by numerous varying conditions, significantly impacting its topology, quality of communication channels, and paths with respect to bandwidth, loss, and delay. This paper introduces a link efficiency and quality of experience aware routing protocol (LEQRV) to improve video streaming provisioning in urban vehicular ad‐hoc networks. LEQRV uses an enhanced greedy forwarding‐based approach to create and maintain stable high quality routes for video streaming delivery. It improves the performance of the quality of experience by increasing the achieved QoE scores and reducing the forwarding end‐to‐end delay and frame loss.