Nara Institute of Science and Technology
Computer networks and traffic systems have, in fact, a lot in common. For example, the method used for traffic jam analysis can also be used to analyze network congestions.
One of these technologies is a network technology applied to traffic systems: ITS, Intelligent Transport Systems (also known as Intelligent Transportation Systems). The ITS consists of everything related to transportation (such as automobiles, railways, ships, and airplanes) that uses information technology, including traffic light control, car navigation systems, ETC (Electronic Toll Collection), automatic ticket gates, automated driving, autopilot, etc.
Among ITS, the ones used in automobiles, particularly, have been increasingly adopting IPv6. In this article, we will take a look at the latest trends in Internet-enabled ITS technology.
Trials for Internet-enabled automobiles have been performed since around 1996. Various applications of the Internet have been evaluated, developed, and field-tested, from simple uses, such as receiving e-mails and checking web pages, to various kinds of systems. A couple examples include a probe-car system that collects data from sensors the automobile has and generates information on traffic jams as well as rainfall, and a system that detects when the car in front of you slips, and operates the accelerator and brake to avoid any dangers.
However, people often ask questions such as “why the Internet?” and “why IPv6?”
Figure 1 shows the communication service architecture for automobiles, which is being evaluated at ISO TC204 WG16. This is shown in a document called ISO/CD 21217 and is called the CALM (Communications, Air Interface, Long and Medium Range) Architecture. In the center of this figure is IPv6, which is the fundamental technology for the Internet. Using IPv6 makes it possible to manage various communication medias, including wireless LAN, cell phones, DSRC (Dedicated Short Range Communication, wireless communication technology used in ETC and such), and to implement applied services, in other words, applications, on the shared communications infrastructure. In the past, for ITS, each service has been building separate communication systems. However, by using the Internet, the communications infrastructure can be shared, and by doing so the cost of implementing services can be lowered.
By the way, in the ISO/CD 21217 document, it is clearly stated that IPv6 is to be used as the Internet protocol. Considering the fact that there are about 80 million cars in Japan and more than 800 million cars in the whole world, there is no predisposition towards IPv4. Due to the fact that IPv4 does not have enough IP addresses for those cars, they naturally decided to use IPv6. At the same time, a technology called Network Mobility (NEMO) Basic Support (RFC 3963) that requires IPv6 has appeared and this is another reason why IPv6 must be used.
There are multiple computers set up inside the car and it is necessary to treat it as a mobile network, not as a mobile node. NEMO is a technology, developed as an extension to Mobile IPv6 (RFC 3775), that supports mobile networks. Mobile IP is a mechanism that associates fixed IP addresses, which identify nodes, and changing IP addresses, which show the location of the nodes, in relation to each other. Since IP addresses that indicated the location each time the device moved had to be discarded after being used, it was difficult to practically implement this technology using IPv4 due to the limitation in the IPv4 address space. Thus, Mobile IP finally became a reality with the appearance of Mobile IPv6. Since NEMO is an extension of this, it has become a technology that requires IPv6. The combination of automobiles and IPv6 was inevitable, which means it was a natural implementation.
In the CALM Architecture in Figure 1, two modules, CME and NME, are provided. These are abstracts of the features that are necessary to implement services in a mobile environment, such as automobiles.
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Figure 1: CALM Architecture
CME stands for CALM Management Entity; one of its features is to receive and manage requests from service applications that operate in mobile systems. For example, this module receives requests such as “secure communications required”, “wide communication band range required”, or “urgent communication”, and passes them onto the network. NME (Network Management Entity) is a module that controls the communication media responding to the requests from CME; it provides features such as managing the availability of communication medias and selecting a media when one is needed, and providing communication connections. In reality, the function shown in Figure 1 is not implemented on one computer; it is built as a mobile network that consists of multiple computers as stated earlier. Thus, the communication protocol used among modules is discussed also in ISO and they are working on standardizing it. This kind of mechanism is being standardized as the ISO/CD 21210 CALM (Communication Air-interface Long and Medium range) Networking Protocols.
Because of this, various research and development activities as well as field trials have been conducted. Especially at the Internet ITS Consortium, field trials focused on business use are being carried out. For example, they are developing a system that detects when a car “slips” and lets the cars behind it know the area of the road that is frozen and dangerous, while at the same time collecting information on the condition of the ABS, information from the horizontal G-sensor, information on the difference of the spinning angle for each of the four wheels, etc. There are also various other deployments being examined, researched and developed, including experiments on collecting information on traffic jams on non-major roads using probe-cars, and collecting driving status information in order to use it for maintenance and insurance services.
Also, they are developing a system that connects ambulances to the Internet in order to let the doctors at the emergency hospitals that are going to admit the patients know their condition.
Connecting cars to the Internet creates more potential for various services and people are working to put it to practical use. ITS start requiring IPv6. It may play an important role as a driver of IPv6 propagation.
Website for Internet ITS Consortium:
http://www.internetits.org/en/top.html
