Modulation and Coding Techniques for Inter-Vehicular Communications

Direct inter-vehicular communications are presumably more difficult to perform than communications within a cellular network or between a moving vehicle and the roadside, where there is a large fixed infrastructure. It is assumed in this chapter that the mobile channel between the two vehicles is so rapidly variable that it is not possible to measure it in real-time. The authors therefore selected and considered only modulation and coding techniques for which the knowledge of the channel state was not necessary at both the transmitter and the receiver, that is, differential and noncoherent communications. To be realistic, only space-time coding communication systems with two transmit antennas were considered. The authors have purposely avoided too much theoretical development, with the intent of making clear that the implementation of all the techniques mentioned in this chapter, it should not be a too difficult task for the electronic technology of today. Future research directions are also suggested to conclude the chapter.

Unpredicted Trajectories of an Automated Guided Vehicle with Chaos

Intelligent Transportation Systems (ITS) are the future of transportation. As a result of emerging standards, vehicles will soon be able to talk to one another as well as their environment. A number of applications will be made available for vehicular networks that improve the overall safety of the transportation infrastructure. This chapter develops a method to impart chaotic motions to an Automated Guided Vehicle (AGV). The chaotic AGV implies a mobile robot with a controller that ensures chaotic motions. This kind of motion is characterized by the topological transitivity and the sensitive dependence on initial conditions. Due the topological transitivity, the mobile robot is guaranteed to scan the whole connected workspace. For scanning motion, the chaotic robot neither requires a map of the workspace nor plans global motions. It only requires the measurement of the workspace boundary when it comes close to it.

Analyzing the Trade-Offs Between Security and Performance in VANETs

Vehicular Ad-hoc NETworks (VANETs) currently provide a prominent field of research, which aims at improving everyday road safety and comfort. To achieve this, the deployment of several potential applications is envisioned, promising to provide extraordinary benefits, but will also represent important security challenges due to the unique characteristics of VANETs. In this chapter, VANET’s security issues are addressed, and the most outstanding security approaches are discussed. As a proof of concept, a PKI -based protocol, able to cope with the interoperability issues among untrusted CA domains is presented, and the trade-offs between security and performance are empirically analyzed and stressed.

Development of Applications for Vehicular Communication Network Environments

Nowadays, modern society faces serious problems with transportation systems. There are more traffic jams, accidents, and fatalities, and CO2 emissions are increasing fast. Thus, improving the safety and efficiency of transportation systems is imperative. Developing a sustainable transportation system requires a better usage of the existing infrastructure, the adoption of emerging technologies (e.g. embedded devices, sensors, and short range radio transmitters), and the development of applications capable of operating in wireless and spontaneous networks. This chapter gives readers a global vision of the issues related to the development of applications for vehicular ad-hoc networks(VANET). It also presents a classification and an overview of the top-level application domain. In addition, it investigates the importance of information in vehicular networks and analyses the requirements for different types of vehicular applications. Finally, the communication schemes that underpin the operation of VANET applications, as well as the security threats they are exposed to, are studied.

Reactive Location-Based Routing Algorithm with Cluster-Based Flooding

Location-Based Routing Algorithm with Cluster-Based Flooding (LORA-CBF) employs two location services: Simple and Reactive. A Simple Location Service has been implemented for neighbors nodes, and for faraway nodes, a Reactive Location Service is employed. In LORA-CBF, the source node includes the location of its destination in each packet. The packet moves hop by hop through the network, forwarded along via cooperating intermediates nodes. At each node, a purely local decision is made to forward the packet to the neighbor that is geographically closest to the destination. However, location information by itself does not guarantee the transmission between neighboring nodes in vehicular ad-hoc networks. Mobility and contention of wireless media may cause loss of packets being transferred, and this is very important aspect to consider in the development of wireless routing algorithms. Here, the authors have addressed this problem by including a predictive algorithm in LORA-CBF.

Experience Developing a Vehicular Network Based on Heterogeneous Communication Technologies

This chapter describes the experiences and findings deploying a vehicular network architecture supporting different communication technologies. This approach has been developed taking into account key issues regarding mobility and security. These two aspects have been provided by means of the NEMO and IKEv2 protocols, respectively. In addition, thanks to the EAP protocol, transported by IKEv2, an extensible authentication method can be used to implement an access control mechanism. This work also focuses on how the terminal is aware of the surrounding environment in order to boost the handoff processes among heterogeneous networks using the IEEE 802.21 protocol. Apart from the description of the on-board system architecture, a WiMAX/WiFi deployment has been set up at the infrastructure side to validate the development of the mobility and security environment designed for vehicular networks.

Cooperative Positioning in Vehicular Networks

This chapter introduces the concept of Cooperative Positioning (CP) for vehicular networks, or more precisely, VANETs (Vehicular Adhoc NETworks), as an application of DSRC (Dedicated Short Range Communication). It includes a comprehensive review of available and hypothetical vehicular positioning technologies. Amongst these, the importance of CP for Location Based Services using DSRC is emphasized, and some important issues are addressed that need to be resolved in order to implement CP successfully with standard DSRC infrastructure. The performance bounds of CP are derived. Ranging between vehicles is identified as the main hurdle to be overcome. Time-based techniques of ranging are introduced, and the bandwidth requirements are investigated. The robustness of CP to inter-node connection failure as well as GPS (Global Positioning System) dropout is demonstrated via simulation. Kalman Filter performance for CP is evaluated, and proven to be efficient under conditions such as the consistency of GPS signal availability ranging between vehicles. CP has, however, shown to increase the positioning accuracy to 1-meter level, even in the deep urban valleys where vehicles frequently become invisible to navigation. Overall, CP is proven to be a viable concept and worthy of development as a DSRC application.

Communication Architectures and Services for Intelligent Transport Systems

Current challenges in mobility and sustainable development are closely related to increasing travel safety, optimizing the use of transport infrastructure, reducing operating and maintenance costs and making public transport more attractive. The proposed solutions to these major challenges depend to a high extent, on political decisions, development of good practices, and also on the innovation and technology introduced through on-going Intelligent Transport Systems (ITS) programs and initiatives. This chapter provides an overview on the communication architectures able to support these ITS programs. In order to do so, this chapter presents the current standardization initiatives in the vehicular environment, a description from the telecom point of view of the different ITS services, and finally, a survey on the radio access technologies capable of dealing with such a demanding scenario.

Evaluation of the LORA-CBF Routing Algorithm with Selective Gateway in an Ad Hoc WiMAX Network

Vehicular Ad-Hoc Networks (VANETs) are characterized by their high mobility, where wireless links between vehicles unpredictably can change. This mobility makes it very challenging to establish and maintain a communication link in vehicular networks; therefore, networking in these kinds of networks has become a very intense area of study. Consequently, research of ad hoc routing and medium access control strategies has become an intensive part of current study. The research community has expressed considerable interest in introducing WiMAX as medium access technology and geographic strategies for routing algorithms. This work presents an evaluation of the LORA-CBF geographic routing algorithm that permits seamless communication in an ad-hoc WiMAX network.

Channel Impairments for V2V Communications in ITS Scenarios

This chapter describes different propagation scenarios in V2V communications based on practical Intelligent Transportation System applications. The intention is the study of propagation impairments for modeling purposes. It is important to consider the environmental characteristics of the scenario in order to choose the proper model to evaluate performance. The intention of this chapter is to explore how well current models fit the scenarios and to identify areas of opportunity for new model design. Many devices including sensors, transponders, and communication radios of different kinds co-exist in a typical urban scene. Interference among these devices and electromagnetic coupling with external waves is possible. Therefore, integration of the various technologies is imperative, and conditions for physical interaction of the radio waves needs to be provided. This is critical for the correct function of automatic systems that control safety sensible information. Very strict standard electromagnetic compatibility restrictions and regulations are applied to vehicles. These emissions and immunity tests need to be reengineered in the near future in order to consider new radio devices for communication among vehicles through sensors and transponders.