A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Communication Methods <s> A primary goal of intelligent transportation systems is to improve road safety. The ability of vehicles to communicate is a promising way to alleviate traffic accidents by reducing the response time associated with human reaction to nearby drivers. Vehicle mobility patterns caused by varying traffic dynamics and travel behavior lead to considerable complexity in the efficiency and reliability of vehicular communication networks. This causes two major routing issues: the broadcast storm problem and the network disconnection problem. In this article we review broadcast communication in vehicular communication networks and mechanisms to alleviate the broadcast storm problem. Moreover, we introduce vehicular safety applications, discuss network design considerations, and characterize broadcast protocols in vehicular networks. <s> BIB001 </s> A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Communication Methods <s> Vehicular ad-hoc networks (VANETs) are a promising communication scenario. Several new applications are envisioned, which will improve traffic management and safety. Nevertheless, those applications have stringent security requirements, as they affect road traffic safety. Moreover, VANETs face several security threats. As VANETs present some unique features (e.g. high mobility of nodes, geographic extension, etc.) traditional security mechanisms are not always suitable. Because of that, a plethora of research contributions have been presented so far. This chapter aims to describe and analyze the most representative VANET security developments. <s> BIB002 </s> A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Communication Methods <s> Diverse applications in vehicular network present specific requirements and challenges on wireless access technology. Although considered as the first standard, IEEE 802.11p shows the obvious drawbacks and is still in the field-trial stage. In this paper, we propose long-term evolution (LTE)-V as a systematic and integrated V2X solution based on time-division LTE (TD-LTE) 4G. LTE-V includes two modes: 1) LTE-V-direct and 2) LTE-V-cell. Comparing to IEEE 802.11p, LTE-V-direct is a new decentralized architecture which modifies TD-LTE physical layer and try to keep commonality as possible to provide short range direct communication, low latency, and high reliability improvements. By leveraging the centralized architecture with native features of TD-LTE, LTE-V-cell optimizes radio resource management for better supporting V2I. LTE-V-direct and LTE-V-cell coordinate with each other to provide an integrated V2X solution. Performance simulations based on sufficient scenarios and the prototype system with typical cases are presented. Finally, future works of LTE-V are envisioned. <s> BIB003 </s> A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Communication Methods <s> As one of the most popular social media platforms today, Twitter provides people with an effective way to communicate and interact with each other. Through these interactions, influence among users gradually emerges and changes people's opinions. Although previous work has studied interpersonal influence as the probability of activating others during information diffusion, they ignore an important fact that information diffusion is the result of influence, while dynamic interactions among users produce influence. In this article, the authors propose a novel temporal influence model to learn users' opinion behaviors regarding a specific topic by exploring how influence emerges during communications. The experiments show that their model performs better than other influence models with different influence assumptions when predicting users' future opinions, especially for the users with high opinion diversity. <s> BIB004 </s> A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Communication Methods <s> Abstract VANET is an emergent technology with promising future as well as great challenges especially in its security. In this paper, we focus on VANET security frameworks presented in three parts. The first presents an extensive overview of VANET security characteristics and challenges as well as requirements. These requirements should be taken into consideration to enable the implementation of secure VANET infrastructure with efficient communication between parties. We give the details of the recent security architectures and the well-known security standards protocols. The second focuses on a novel classification of the different attacks known in the VANET literature and their related solutions. The third is a comparison between some of these solutions based on well-known security criteria in VANET. Then we draw attention to different open issues and technical challenges related to VANET security, which can help researchers for future use. <s> BIB005 </s> A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Communication Methods <s> The C-V2X or LTE-V standard has been designed to support vehicle to everything (V2X) communications. The standard is an evolution of LTE, and it has been published by the 3GPP in Release 14. This new standard introduces the C-V2X or LTE-V Mode 4 that is specifically designed for V2V communications using the PC5 sidelink interface without any cellular infrastructure support. In Mode 4, vehicles autonomously select and manage their radio resources. Mode 4 is highly relevant since V2V safety applications cannot depend on the availability of infrastructure-based cellular coverage. This paper presents the first analytical models of the communication performance of C-V2X or LTE-V Mode 4. In particular, the paper presents analytical models for the average packet delivery ratio (PDR) as a function of the distance between transmitter and receiver, and for the four different types of transmission errors that can be encountered in C-V2X Mode 4. The models are validated for a wide range of transmission parameters and traffic densities. To this aim, this study compares the results obtained with the analytical models to those obtained with a C-V2X Mode 4 simulator implemented over Veins. <s> BIB006
The ITS is consistently focused on providing secure communication to improve the traffic flow, road safety, and also overcome the traffic congestion by utilizing different networking techniques such as MANETs and VANETs. V2X communications play an important role in the ITS to improve the traffic efficiency, traffic safety, and enhance driving experiences by providing real-time and highly reliable information such as collision warning, road bottlenecks information, traffic congestions warning, emergency situations, and other transportation services BIB004 . V2X communication can exchange the information between V2V, V2I, and vehicle to pedestrians (V2P), as shown in Figure 1 . In V2V communication, the transmission medium is characterized by a high transmission rate and short latency BIB005 BIB001 . In the V2V, a vehicle can broadcast useful information such as emergency braking, collision detection, and traffic conditions among each other. The V2I is used to transmit useful information between vehicles and network infrastructures. In this domain, the vehicle developed a connection with RSUs to exchange information with other networks such as the Internet. Furthermore, due to communication with the infrastructure, the V2I require large bandwidth than V2V but is less vulnerable to attacks  . Recently, C-V2X technology was introduced. It is a unified connectivity platform that aims to support V2X communications BIB006 . The C-V2X is developed within the third generation partnership project (3GPP) and regarded as the robust communication technology that can accomplish V2X communications  . It connects each vehicle and enables the cooperative intelligent transport systems (C-ITS) that reduce the traffic congestion and enhance traffic efficiency  . In the year 2016, 3GPP released its first version to support V2X communications, and the standards are referred as LTE-V, long-term evolution (LTE), and C-V2X  . LTE possess robust benefits in V2I communication because of its high data rate, large coverage, and penetration rate BIB003 . However, in V2V communication, LTE faces many challenging issues due to lack of its centralized structure and limited services to support V2V communication BIB003 . The VANET communication is further classified into four categories BIB002 , which are shown below.