LVAP: Lightweight V2I authentication protocol using group communication in VANETs

The authentication protocol is vital for the security of the wireless sensor network to resist the known threats, such as eavesdropping, replay attack, man‐in‐the‐middle attack, etc. In this paper, a lightweight authentication protocol for vehicular ad hoc networks is proposed using the symmetric encryption, the group communication method, and the proactive authentication technique, which not only achieves the desired security goals but also guarantees the practical anonymity and the accountability. The analysis demonstrates that the proposed protocol works properly in the high‐density and the low‐density traffic environment.     

车联网数据聚集研究综述

当今,车联网是实现智能交通应用的平台。车联网有着特殊的网络特征,使得其上的数据聚集算法不同现有的无线传感器网络数据聚集。数据聚集可以有效地降低传输过程中的数据量,但同时亦会引起数据时延的增加和数据精度的降低。因此聚集算法往往考虑聚集数据的时延和精度。本文对现有的车联网聚集算法进行综述分析。     

Routing using reinforcement learning in vehicular ad hoc networks

In vehicular ad hoc networks (VANETs), the frequent change in vehicle mobility creates dynamic changes in communication link and topology of the network. Hence, the key challenge is to address and resolve longer transmission delays and reduced transmission stability. During the establishment of routing path, the focus of entire research is on traffic detection and road selection with high traffic density for increased packet transmission. This reduces the transmission delays and avoids carry-and-forward scenarios; however, these techniques fail in obtaining accurate traffic density in real-time scenario due to rapid change in traffic density. Thus, it is necessary to create a model that efficiently monitors the traffic density and assist VANETs in route selection in an automated way with increased accuracy. In this article, a novel machine learning architecture using deep reinforcement learning (DRL) model is proposed to monitor and estimate the data essential for the routing protocol. In this model, the roadside unit maintains the traffic information on roads using DRL. The DRL predicts the movement of the vehicle and makes a suitable routing path for transmitting the packets with improved transmission capacity. It further uses predicted transmission delays and the destination location to choose the forwarding directions between two road safety units (RSUs). The application of DRL over VANETs yields increased network performance, which provides on-demand routing information. The simulation results show that the DRL-based routing is effective in routing the data packets between the source and destination vehicles than other existing method.     

A geographic routing protocol based on trunk line in VANETs

A Trunk Line Based Geographic Routing(TLBGR) protocol in Vehicular Ad-hoc Networks (VANETs) is proposed in this paper to solve the problem of data acquisition in the traditional trunk coordinated control system. Because of the characteristics of short communication time and high packet loss among vehicles, the vehicles entering the trunk lines can not transmit their information to the trunk coordinated control system stably. To resolve this problem, the proposed protocol uses the trunk lines’ traffic flow and the surrounding road network to provide a real-time data transmission routing scheme. It takes into account the data congestion problem caused by the large traffic flow of the main roads, which leads to the corresponding increase of the information flow of the section and the package loss, and the link partition problem caused by the insufficient traffic flow, which makes the vehicles have to carry and relay information thus increasing the transmission delay. The proposed TLBGR protocol can be divided into two stages: the next-intersection selection, and the next-hop selection in the chosen path between the current and next intersections. Simulation results show that, compared with other IoT routing protocols including Greedy Perimeter Stateless Routing (GPSR), Ad-hoc On Demand Vector (AODV), and Q-AODV, the TLBGR protocol has better performance in aspects of end-to-end delay, delivery rate, and routing cost under the scenario of urban traffic trunk lines. The TLBGR protocol can effectively avoid data congestion and local optimum problems, increase the delivery rate of data packets, and is therefore suitable for the routing requirements in this application scenario.     

一种基于局部连通性的增强型车载网多跳广播协议

在车载网中,许多应用都依赖于可靠高效的消息广播。由于无线信道共享介质的特性,消息广播不得不面临广播风暴问题。概率广播是一类能抑制广播风暴的简单有效的方法,然而车载网中除DV-CAST以外的概率广播协议均未考虑稀疏节点场景下的网络分割问题。在分析和验证DV-CAST协议固有缺点的基础上,借鉴其利用局部连通性进行转发决策的思想,提出了一种基于局部连通性的增强型多跳广播协议。实验表明,提出的协议能在稠密节点及稀疏节点场景中均取得较好的可靠性并具有较低开销。     

NLOS环境下的车辆位置信息协作式获取和验证方法

车载网VANETs中网络服务和应用需不断交互车辆的位置信息,而节点之间的障碍物使两车间产生非视线距离NLOS(nonline of sight),同时也阻碍位置信息的交互.针对如何获取车辆可靠的位置信息,提出了一种位置信息协作式获取方法.首先在假设条件成立的情况下,建立车辆协作式位置信息获取模型,同时基于三角算法获取车辆位置信息;其次,设计协议算法对所获得的信息结合距离计算进行二次完整性验证;最后用仿真软件对所提出的位置信息获取和验证的算法分析,从感知率、信道利用率、发送成功率和响应时间等指标对算法进行了评价.仿真结果表明,NLOS环境下的车辆位置信息协作式获取和验证方法有利于维护NLOS环境下定位服务准确性,能够对所获取的信息进行正确性判断,有一定的借鉴价值.     

基于路径中断概率的VANETs连接模型及性能分析

车载网VANETs（Vehicular Ad hoc Networks）在道路安全、车流量管理和娱乐应用具有广阔的前景,而这些应用依赖数据有效的传输。为此,VANETs的数据传输技术成为研究的焦点。然而,VANETs的拓扑动态变化、车辆快速移动加速了车间通信链路的断裂,降低了链路的可靠性,为数据有效传输提出了挑战。据此,分析了VANETs的多跳通信连接特性。通过研究端到端中断概率,提出多跳连接的分析模型。通过模型,可得出在一定的平均端到端中断概率所需的最小发射功率以及最大传输跳数。通过仿真,验证理论模型的正确性。仿真进一步表明,通过合适的功率控制算法有利于改善数据传输路径。     

Dynamic Event-Triggered Scheduling and Platooning Control Co-Design for Automated Vehicles Over Vehicular Ad-Hoc Networks

This paper deals with the co-design problem of event-triggered communication scheduling and platooning control over vehicular ad-hoc networks (VANETs) subject to finite communication resource. First, a unified model is presented to describe the coordinated platoon behavior of leader-follower vehicles in the simultaneous presence of unknown external disturbances and an unknown leader control input. Under such a platoon model, the central aim is to achieve robust platoon formation tracking with desired inter-vehicle spacing and same velocities and accelerations guided by the leader, while attaining improved communication efficiency. Toward this aim, a novel bandwidth-aware dynamic event-triggered scheduling mechanism is developed. One salient feature of the scheduling mechanism is that the threshold parameter in the triggering law is dynamically adjusted over time based on both vehicular state variations and bandwidth status. Then, a sufficient condition for platoon control system stability and performance analysis as well as a co-design criterion of the admissible event-triggered platooning control law and the desired scheduling mechanism are derived. Finally, simulation results are provided to substantiate the effectiveness and merits of the proposed co-design approach for guaranteeing a trade-off between robust platooning control performance and communication efficiency.      

Adaptive Handover Decision Inspired By Biological Mechanism in Vehicle Ad-hoc Networks

In vehicle ad-hoc networks (VANETs), the proliferation of wireless communication will give rise to the heterogeneous access environment where network selection becomes significant. Motivated by the self-adaptive paradigm of cellular attractors, this paper regards an individual communication as a cell, so that we can apply the revised attractor selection model to induce each connected vehicle. Aiming at improving the Quality of Service (QoS), we presented the bio-inspired handover decision-making mechanism. In addition, we employ the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) for any vehicle to choose an access network. This paper proposes a novel framework where the bio-inspired mechanism is combined with TOPSIS. In a dynamic and random mobility environment, our method achieves the coordination of performance of heterogeneous networks by guaranteeing the efficient utilization and fair distribution of network resources in a global sense. The experimental results confirm that the proposed method performs better when compared with conventional schemes.     

Mobility aware and dual phase AODV protocol with adaptive hello messages over vehicular ad hoc networks

Establishing stable routes over high mobility networks is a challenging field and consequently brought the attention of a lot of current researchers. In this article, a new reactive routing protocol has been proposed which is considered as a major extension of both Ad-hoc On-demand Distance Vector (AODV) and Mobility and Direction Aware AODV (MDA-AODV) prior routing protocols. It is named as Mobility Aware and Dual Phase Ad-hoc On-demand Distance Vector with Adaptive Hello Messages (MA-DP-AODV-AHM). It primarily concentrates on building routes considering vehicles’ speeds and direction of motion with respect to source vehicles, thereby establishing more stable routes and reducing the route breakages. Not only to this extent, but rather, we proposed an adaptive control packet announcement mechanism, which is directly connected to the periodic hello messages approach, with vehicles’ speeds, yielding a significant reduction in the amount of control overhead and congestion over the network. Moreover, the new protocol is proposed to alternate working among two phases, for the reason of guaranteeing the generation of efficient routes on a timely basis, which include MA-DP-AODV-AHM and AODV protocols. Our protocol has been evaluated in terms of control overhead, end-to-end delay, and energy consumption using QualNet simulator version 7.1 in which enormous simulations have been conducted under the base of vehicle density, packet rate, and constant bit rate connections. Simulation results summarize that MA-DP-AODV-AHM contributes efficiently in mitigating the network instability through generating effective stable routes and reducing link failures. Furthermore, it has proved its superiority over AODV and MDA-AODV.