ABSTRACT
The adequately working monitoring and intelligent surveillance layer in the hierarchical intelligent trafc system (HITS) system is potentially able directly or indirectly, through other layers, essentially improve wide-area operational efciency and productivity of the whole transportation system. This chapter presents a proposal that collaborative implementations of vehicular telematics working in heterogeneous wireless networks environment are essential enabling technology for the HITS system. Advanced heterogeneous vehicular network (AHVN) architectures and intervehicle (vehicle-to-vehicle [V2V]) communication (IVC) and vehicle-to-infrastructure (V2R) communication tools use multiple access technologies and multiple radios in a collaborative manner. The modern HITS multilayer integrated trafc management, surveillance, and control activities can be essentially improved by real-time intelligent reactions on properly detected trafc incidents. This is a challenging task in the context of the very high complexity of trafc phenomena. The collaborative AHVN-IVC support activities for trafc incident detection, recognition, and diagnosis should establish the challenges and rules in designing the essential functional components of AHVN and the corresponding protocols. The illustrative practical examples of real-time control preference recognition based on AHVN-IVC support creates very attractive practical proposals for HITS system operation. Vehicular platforms with telematics services provide key support for development of integrated intelligent transportation system (ITS) options to achieve safety and productivity in
Introduction ...................................................................................................................................... 47 ITS Hierarchical Multilayer System ................................................................................................48 Application of Vehicle Telematics ...................................................................................................50 Wireless Networks ........................................................................................................................... 53
Security and Privacy Aspects ...................................................................................................... 55 Practical Examples of Cooperative Implementation in ITS Systems .............................................. 55 Conclusions ...................................................................................................................................... 58 References ........................................................................................................................................ 58
transportation. Wireless communications and networking technologies such as IEEE 802.11 (WiFi), IEEE 802.16 (Worldwide Interoperability for Microwave Access [WiMAX]), 3G cellular, and satellite technologies to support data communications for vehicular telematics. ITS applications can be supported by vehicle-to-roadside (V2R) and V2V communications. V2R involves vehicular nodes and roadside base stations. IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), and dedicated short-range communications (DSRC) technologies can be used in this model of communication. In particular, with the DSRC standard, onboard units (OBUs) placed at each vehicle can send/receive data to/from roadside units (RSUs). However, if a vehicle cannot directly send its data to an RSU, it can relay its data to other vehicles until the data reach the RSU using a multihop transmission strategy. It is also possible that OBUs form a group and elect the group leader. In this case, all group member OBUs will send their reports to the leader OBU, which will aggregate them and forward the resulting message(s) to the RSU. There are several applications for this communication model, such as electronic toll collection, infotainment services, safety message dissemination, and Web browsing. The OBUs are typically equipped with an onboard computer, communication interface, and global positioning system (GPS), which provides information on vehicle position in real time, and an event data recorder, which stores relevant data that, in case of an accident, can be used in forensic analysis. RSUs act as base stations or access points (APs) and are connected to application servers. V2V communications with vehicular nodes on a road form a vehicular ad hoc network (VANET), which is mainly used in safety warning systems, trafc information systems, and multimedia services. Collision avoidance, road obstacle warning, intersection collision warning, and lane change assistance are example applications of V2V communications. Most V2V safety applications require low transfer latency since these applications are used in a dynamic and unpredictable trafc environment. Most research tends to nd improvements in such medium access control (MAC) protocols, transmission strategies, and wireless technologies in order to reduce the latency. By denition, emerging vehicular telematic applications will be wireless. In the past, the wireless services for individuals were dedicated to alternative route selection in a more or less independent manner. This chapter provides a HITS dedicated survey on the research issues, challenges, and possible approaches to tackle these challenges for vehicular telematics over heterogeneous wireless networks.
