Vehicular ad hoc network (VANET) is an emerging new technology integrating ad hoc network, wireless LAN (WLAN) and cellular technology to achieve intelligent inter-vehicle communications and improve road traffic safety and efficiency. VANETs are distinguished from other kinds of ad hoc networks by their hybrid network architectures, node movement characteristics, and new application scenarios. Therefore, VANETs pose many unique networking research challenges, and the design of an efficient routing protocol for VANETs is very crucial. In this article, we discuss the research challenge of routing in VANETs and survey recent routing protocols and related mobility models for VANETs.

/pdf/routing-in-vehicular-ad-hoc-networks-a-survey-2fwcriwix4.pdf

Routing in vehicular ad hoc networks: A survey

Vehicular ad hoc networks using WLAN technology have recently received considerable attention. We present a position-based routing scheme called Connectivity-Aware Routing (CAR) designed specifically for inter-vehicle communication in a city and/or highway environment. A distinguishing property of CAR is the ability to not only locate positions of destinations but also to find connected paths between source and destination pairs. These paths are auto-adjusted on the fly, without a new discovery process. "Guards" help to track the current position of a destination, even if it traveled a substantial distance from its initially known location. For the evaluation of the CAR protocol we use realistic mobility traces obtained from a microscopic vehicular traffic simulator that is based on a model of driver behavior and the real road maps of Switzerland.

http://www.lst.ethz.ch/research/publications/INFOCOM_2007/INFOCOM_2007.pdf

Connectivity-Aware Routing (CAR) in Vehicular Ad-hoc Networks

This paper presents a class of routing protocols called road-based using vehicular traffic (RBVT) routing, which outperforms existing routing protocols in city-based vehicular ad hoc networks (VANETs). RBVT protocols leverage real-time vehicular traffic information to create road-based paths consisting of successions of road intersections that have, with high probability, network connectivity among them. Geographical forwarding is used to transfer packets between intersections on the path, reducing the path's sensitivity to individual node movements. For dense networks with high contention, we optimize the forwarding using a distributed receiver-based election of next hops based on a multicriterion prioritization function that takes nonuniform radio propagation into account. We designed and implemented a reactive protocol RBVT-R and a proactive protocol RBVT-P and compared them with protocols representative of mobile ad hoc networks and VANETs. Simulation results in urban settings show that RBVT-R performs best in terms of average delivery rate, with up to a 40% increase compared with some existing protocols. In terms of average delay, RBVT-P performs best, with as much as an 85% decrease compared with the other protocols.

/pdf/vanet-routing-on-city-roads-using-real-time-vehicular-55pimdab06.pdf

VANET Routing on City Roads Using Real-Time Vehicular Traffic Information

As the rapid development of automotive telematics, modern vehicles are expected to be connected through heterogeneous radio access technologies and are able to exchange massive information with their surrounding environment. By significantly expanding the network scale and conducting both real time and long term information processing, the traditional Vehicular Ad- Hoc Networks U+0028 VANETs U+0029 are evolving to the Internet of Vehicles U+0028 IoV U+0029, which promises efficient and intelligent prospect for the future transportation system. On the other hand, vehicles are not only consuming but also generating a huge amount and enormous types of data, which are referred to as Big Data. In this article, we first investigate the relationship between IoV and big data in vehicular environment, mainly on how IoV supports the transmission, storage, computing of the big data, and in return how IoV benefits from big data in terms of IoV characterization, performance evaluation and big data assisted communication protocol design. We then investigate the application of IoV big data for autonomous vehicles. Finally the emerging issues of the big data enabled IoV are discussed.

Internet of vehicles in big data era

The chapter provides a survey of routing protocols in vehicular ad hoc networks. The routing protocols fall into two major categories of topology-based and position-based routing. The chapter discusses the advantages and disadvantages of these routing protocols, explores the motivation behind their design and trace the evolution of these routing protocols. Finally, it concludes the chapter by pointing out some open issues and possible direction of future research related to VANET routing. INTRODUCTION With the sharp increase of vehicles on roads in the recent years, driving has not stopped from being more challenging and dangerous. Roads are saturated, safety distance and reasonable speeds are hardly respected, and drivers often lack enough attention. Without a clear signal of improvement in the near future, leading car manufacturers decided to jointly work with national government agencies to develop solutions aimed at helping drivers on the roads by anticipating hazardous events or avoiding bad traffic areas. One of the outcomes has been a novel type of wireless access called Wireless Access for Vehicular Environment (WAVE) dedicated to vehicle-to-vehicle and vehicle-to-roadside communications. While the major objective has clearly been to improve the overall safety of vehicular traffic, promising traffic management solutions and on-board entertainment applications are also expected by the different bodies (C2CCC, VII, CALM) and projects (VICS (Yamada, 1996), CarTALK 2000 (Reichardt D, 2002), NOW, CarNet (Morris R, 2000), FleetNet (Franz, 2001)) involved in this field. When equipped with WAVE communication devices, cars and roadside units form a highly dynamic network called a Vehicular Ad Hoc Network (VANET), a special kind of Mobile AdHoc Networks (MANETs). While safety applications mostly need local broadcast connectivity, it is expected that some emerging scenarios (Lee, 2009) developed for intelligent transportation systems (ITS) would benefit from unicast communication over a multi-hop connectivity. Moreover, it is conceivable that applications that deliver contents and disseminate useful information can flourish with the support of multi-hop connectivity in VANETs. Although countless numbers of routing protocols (Mauve, 2001; Mehran, 2004) have been developed in MANETs, many do not apply well to VANETs. VANETs represent a particularly challenging class of MANETs. They are distributed, self-organizing communication networks formed by moving vehicles, and are thus characterized by very high node mobility and limited degrees of freedom in mobility patterns. As shown in Figure 1, there are two categories of routing protocols: topology-based and geographic routing. Topology-based routing uses the information about links that exist in the network to perform packet forwarding. Geographic routing uses neighboring location information to perform packet forwarding. Since link information changes in a regular basis, topology-based routing suffers from routing route breaks. Car 2 Car Communication Consortium, http://www.car‐to‐car.org The Vehicle Infrastructure Integration (VII) Initiative, http://www.vehicle‐infrastructure.org Continuous Air Interface for Long and Medium Interface (CALM), http://www.calm.hu Vehicle Information and Communication System Network On Wheels, www.network‐on‐wheels.de Figure 1: Taxonomy of Various Routing Protocols in VANET Despite many surveys already published on routing protocols in MANETs (Mauve, 2001; Mehran, 2004Giordano, 2003; Stojemnovic, 2004), a survey of newly developed routing protocols specific to VANETs has long been overdue. Li et al. (2007) have made an effort to introduce VANET routing protocols, yet there is still deficiency in a thorough and comprehensive treatment on this subject. A discussion of VANET topics and applications is incomplete without detailed coverage of relevant routing protocols and their impact on overall VANET architecture. In this book chapter, we seek to provide the missing building blocks by detailing the advances in VANET routing protocols. Section III describes the VANET architecture and its characteristics. Section IV presents a survey of these protocols experimented on or tailored to VANET and their advantages and disadvantages. It will explore the motivation behind their design and trace the evolution of these routing protocols. Finally, Section V will point out some open issues and possible direction of future research, and then conclude the book chapter.

Survey of Routing Protocols in Vehicular Ad Hoc Networks

One of the major issues that affect the performance of Mobile Ad hoc NETworks (MANET) is routing. Recently, position-based routing for MANET is found to be a very promising routing strategy for inter-vehicular communication systems (IVCS). However, position-based routing for IVCS in a built-up city environment faces greater challenges because of potentially more uneven distribution of vehicular nodes, constrained mobility, and difficult signal reception due to radio obstacles such as high-rise buildings. This paper proposes a new position-based routing scheme called Anchor-based Street and Traffic Aware Routing (A-STAR), designed specifically for IVCS in a city environment. Unique to A-STAR is the usage of information on city bus routes to identify an anchor path with high connectivity for packet delivery. Along with a new recovery strategy for packets routed to a local maximum, the proposed protocol shows significant performance improvement in a comparative simulation study with other similar routing approaches.

/pdf/a-star-a-mobile-ad-hoc-routing-strategy-for-metropolis-5ala8bkx7e.pdf

A-STAR: A Mobile Ad Hoc Routing Strategy for Metropolis Vehicular Communications

One of the major issues that affect the performance of mobile ad hoc networks (MANET) is routing. Recently, position-based routing for MANET is found to be a very promising routing strategy for inter-vehicular communication systems (IVCS). However, position-based routing for IVCS in a built-up city environment faces greater challenges because of potentially more uneven distribution of vehicular nodes, constrained mobility, and difficult signal reception due to radio obstacles such as high-rise buildings. This paper proposes a new position-based routing scheme called Anchor-based Street and Traffic Aware Routing (A-STAR), designed specifically for IVCS in a city environment. Unique to A-STAR is the usage of information on city bus routes to identify an anchor path with high connectivity for packet delivery. Along with a new recovery strategy for packets routed to a local maximum, the proposed protocol shows significant performance improvement in a comparative simulation study with other similar routing approaches.

A Routing Strategy for Metropolis Vehicular Communications

Home networks, interlinking devices like fridges, air conditioners, home theatres, security devices, lighting systems are about to realize the concept of a smart home. Among the competing technologies, Bluetooth, with its low cost, low power consumption and its easily configurable devices has emerged as one of the most suitable wireless standard for home networks. In order to find a large market for any automated home system, it must be user friendly, since most consumers are non-technical users. Hence, plug and play is an important feature that must be incorporated into any home network environment. In this paper we suggest a method for data transfer, through the proposed HomeBT protocol. This protocol provides plug and play feature to appliances, in home networks using the Bluetooth technology. Further, an appliance/spl I.bar/changed/spl I.bar/status command and status change event have been suggested as additions in the Bluetooth HCI specifications.

Protocol for plug and play in Bluetooth based home networks

Prefetching and I/O Parallelism in Multiple Disk Systems.

In a mobile ad hoc network (MANET), packet broadcast is common and frequently used to disseminate information. Broadcast consume large amount of bandwidth resource, which is scarce in MANET environment. The problem is to find the ideal forward node set so as to minimize the bandwidth consumed, which is a NP-Complete problem. In this paper we will investigate three dominant node approximation algorithms: dominant pruning, total dominant pruning and partial dominant pruning algorithm. An extension to the original algorithms, modified termination criteria, is proposed. Simulation results show that the new termination criteria ensure the same coverage using a reduced number of forward nodes.

Keok-Kee Lee

Papers

A-STAR: A Mobile Ad Hoc Routing Strategy for Metropolis Vehicular Communications

A Routing Strategy for Metropolis Vehicular Communications

Protocol for plug and play in Bluetooth based home networks

Prefetching and I/O Parallelism in Multiple Disk Systems.

Performance of New Broadcast Forwarding Criteria in MANET