InternetCAR: Internet-Connected Automobiles
Keisuke UEHARA <firstname.lastname@example.org>
Hideki SUNAHARA <email@example.com>
Osamu NAKAMURA <firstname.lastname@example.org>
This paper describes the concept, experiments, and research of the InternetCAR (Connected Automobile) project operated by the WIDE Project. The goal of this project is to connect automobiles to the Internet to provide general Internet connectivity among automobiles and fixed nodes. One of the assumptions is that all of the (several hundred million) automobiles in the world are connected to the Internet. An automobile is a mobile object that provides space for a human being, it has an electric power supply from batteries. The object has various valuable sensor information, such as thermometer and speedometer values. Thus, when an automobile becomes an Internet object, a very large number of mobile sensors exist.
A hardware to retrieve the sensor information -- such as geographic location, velocity, switch status (light, wiper position, air conditioner, brake, cruise control, and so on) was designed and implemented. The design and implementation of a software and communication structure to support stable wireless connectivity to the Internet were also achieved. The prototype system provides general Internet connectivity in an automobile, and allows clients on the Internet to access information from automobiles. A sample application is a rain condition monitoring system by the information retrieved from wiper positions of the Internet connected automobiles together with their locations. This paper discusses the communication architecture, the hardware design, and the evaluations of the prototype systems. The plan for the future experiments also is described.
Automobiles are globally distributed objects that are providing a mobile and ubiquitous environment for human activities. The conventional technologies have been providing information to people in a car via signboards, radio system, mobile phones, and more sophisticated technologies relating to automobile communication. The Internet technologies can integrate these systems into a general digital communication infrastructure.
Once we assume that the automobiles are Internet-accessible, the sensor functions of an automobile can construct a valuable information structure on the Internet. Automobiles on the Internet are not only for people accessing information on the Internet, but also for people on the Internet to monitor the automobile itself, including various environmental information generated from the sensors on the automobile. For example, when the wiper positions of automobiles are monitored, then rain in a certain area can be detected.
The InternetCAR project was started in July 1997. The purpose of the project is to connect automobiles to the Internet in a transparent manner, regardless of their mobility and the wireless connectivity, then achieve the new information structure using the sensor information of the automobiles. Current members of the projects are from automobile industries, wireless communication industries, and computer industries, such as Isuzu Advanced Engineering Center, LTD., Honda R&D CO., LTD., NTT Mobile Communications Network Inc., Nippon Telegraph and Telephone Corp. Wireless Lab., and NTT Central Personal Communications Network Inc. This project is divided into three phases. Phase 1 was started in July 1997 and ended in September 1997 with a modified automobile by Honda which has extra dynamo to supply electric power and car navigation information. Phase 2 was started in October 1997 and will end in March 1998. In this phase, about 20 normal automobiles are used for the experiment. Each automobile loads a computer, a data collection box, a GPS receiver, and a cellular phone to achieve the system which is described in section "Hardware." In April 1998, phase 3 is planned to start, with the redesign of the hardware based on the result of the phase 2, focusing on design toward mass production.
Automobiles have a battery. It is an important matter to use electric equipment. An automobile battery usually has sufficient capacity to operate InternetCAR's equipment. An InternetCAR has the following equipment: a computer, a data collection box, a Global Positioning System (GPS) receiver, and a communication device. The role of each piece of equipment is discussed in the section "Hardware."
The rest of this paper is organized as follows: first, we explain the differences between the aim of related works and the aim of this project. More details, such as problems, are introduced in the next section. Thus, a system overview is shown. The system prototypes are tested. After that, a future plan of this project is described. The last section concludes this paper.
Recently, there have been several related projects. Development and experiment of several types of Intelligent Transport Systems (ITS) are started in several activities.
ITS are designed for providing dynamic information to navigate automobiles such as traffic jam information, map update information, etc. ITS-related systems today are retrieving information from the information center. For example, with traffic jam information, navigation systems can show an optimal route to the driver. However, they are only used to send the information to the automobile.
Some of the car navigation systems have the capability to access Web sites via a cellular phone. Because connection between automobiles and the Internet is restricted (i.e., slow and unstable), these Web sites are specially designed for car navigation systems. Data on these Web sites are designed as lightweight and concentrated for the navigation-related information . For example, the Web sites for this system contain sightseeing information. A driver and passengers on the automobile find the recommended restaurant from this information. This system is also designed for single directional information retrieval.
In order to provide the bi-directional nature of the Internet in an automobile, stable connectivities between an automobile and the Internet have to be achieved. Then, the information model on the global Internet considering the automobile functions has to be designed. Unlike all the efforts to benefit drivers and automobile traffic system, the InternetCAR is trying to achieve the future general information infrastructure on the Internet with the explicit consideration of automobiles, the most typical mobile digital environment.
This section describes the goal of this project and problems in achieving the goal. There are some problems in connecting automobiles to the Internet with current technologies. Some of the problems are caused by particular communication devices. Wireless communication devices are not familiar to the Internet systems. Other problems are owing to usage of automobiles. Current Internet architecture isn't designed for such a special environment.
All current related works aim to use automobiles as a client host. The works can be categorized into two types: information retrieving and emergency call. There are no ideas to provide information from automobiles except geographical location information. The location information is used to point at automobiles in emergency call applications and navigation systems.
This project provides a system to use automobiles as problems not only to use them as client hosts. At this point, it is important to know how to express automobiles in the Internet. We have to consider identifier of automobiles and communication systems.
This project is planning to develop applications to use automobiles as probes in addition to applications of current related works. These applications are familiar to the Internet because of a spirit of cooperation. To develop these applications, we have to design the system of information infrastructure.
An actual example of the applications is rain information. When the wipers of an automobile are working, it may be raining. Another application is traffic information. If an automobile runs slowly, there may be a traffic jam, car accident, or something. Anyway, it is a good idea to avoid the way.
To connect automobiles to the Internet, wireless communication devices are indispensable. There are many wireless digital communication infrastructures such as cellular phones, PHS, wireless LANs, and so on. These wireless communication devices are currently used to connect to the Internet. Wireless LAN devices are designed for LAN environments, needless to say. Cellular phone systems have recently begun shifting to digital systems to be familiar multimedia communications. In fact, digital cellular phone systems and PHS systems can carry various data including IP datagrams by Point-to-Point Protocol (PPP).
However, it is difficult to efficiently use wireless communication devices in the Internet environment. Current wireless communication devices have error collection mechanisms because the wireless communication link is unstable in general. In this situation, instability appears as unsettled delays. On the other hand, Transmission Control Protocol (TCP) uses expansion of the delay as a warning of congestion.
In related works introduced in the section "Related works," automobiles are operated as a client host. It connects to the Internet and browses information using a HTTP client. Therefore automobiles don't need identifiers. Allocating a temporary IP address is sufficient to achieve this purpose.
However, a specific identifier is necessary to develop the applications introduced in the top of this section. To make traffic information, an automobile must be traced by other hosts. Any identifier can be used if it can identify the specific automobile.
Automobiles are not always connected to the Internet. When an automobile is parked, it can't provide power to InternetCAR equipment. If it is necessary to access the automobiles any time, a proxy is required on fixed networks. Another solution is that the application be designed so it doesn't require continuous access.
We developed a prototype of the InternetCAR. This section introduces the system overview. Figure 2 shows an overview of the system.
An InternetCAR has five major devices added to it: a computer, a GPS receiver, a data collection box, a wireless LAN device, and a cellular phone. A computer is used as a router and a probing agent. A Unix operating system (BSDI's BSD/OS 3.0) is installed in the computer. It retrieves sensor data via a data collection box. The box has 26 channels of analog input, 8 channels of digital input, and 2 channels of pulse input. Input terminals are connected to sensors or switches. Currently, the following data can be probed: headlights status, positioning lights status, wiper position, and speed pulse. The computer and the box are connected by an RS-232c interface. The data collection box has one more RS-232c interface for a GPS receiver. A cellular phone is connected to the computer using a modem PC card. The cellular phone has a 28.8K bps pipe.
In this project, some special communication mechanisms are installed in the system. These mechanisms provide stable data transmission.
Mobile-IP is used to provide access transparency to a host in an automobile. In this system, IP address is dynamically allocated by IPCP of PPP or DHCP. Therefore, IP address will be changed every migration. When a correspondent host tries to send data to a mobile host in an automobile, it has to know a new address of the mobile host anyhow. To solve this problem, Mobile-IP is introduced to the system.
On the other hand, we developed Light Weight Protocol (LWP) architecture for a low throughput and long delay link. This protocol is designed as an integration of interface, IP, and TCP layer protocols. LWP architecture can be separated into two functions. LWP is a protocol which is designed to reduce its overhead. TCP/IP has a large header to use in the low throughput link environment. Some fields of the TCP/IP header are omitted as header compression mechanism of PPP. Another function is intercepting TCP connection. A mobile host and a correspondent host are usually connected by TCP. In LWP architecture, an intermediate route, which is located between wired network and wireless network, intercepts the TCP connection and relay using LWP. Figure 3 shows an overview of these mechanisms.
Mobile-IP and LWP are selectable.
Addition, the InternetCAR system has an automatic file transfer mechanism. A user can schedule to retrieve from and upload data to a fixed host as UUCP over TCP. The difference between this mechanism and UUCP is adaptation to an unstable connection. This mechanism watches on network interfaces of a mobile host. When the specified interface is set up, the mechanism starts file transfer by user preference.
Some middleware systems are introduced to provide a mobile computing system.
Dynamic DNS is used with LWP. LWP is not familiar to mobile protocols such as Mobile-IP or VIP. Therefore, when a mobile host uses LWP, a binding a hostname to IP address must be changed. Dynamic DNS can support this mechanism. When a mobile host is connected by LWP, the mobile host register configured IP address by DNS UPDATE message of Dynamic DNS.
Service Location Protocol is installed to look up nearest servers. In some application services or middleware services, any server can provide the same service. DNS is typical of these services.
Remote resource access is important because of limited resources on mobile computers. InternetCAR system has a distributed file system called a Personal File System (PFS). PFS provides capability of a disconnected operation and an asynchronous operation. PFS has three modes of operation: NFS mode, low bandwidth mode, and disconnected mode. In the InternetCAR environment, NFS mode is used in a garage with a wireless LAN device, and low bandwidth mode is used with a cellular phone.
An InternetCAR moves around geographically, needless to say. This means if an InternetCAR can be traced as to its location, users on the Internet can know where their friend is. Also, other various things can be supported. In this system, a Geographical Location Information (GLI) system is introduced for the purpose. GLI system is a kind of distributed database system. It is constructed with a GLI home server, GLI area server, GLI agent, and GLI client. Each GLI agent belongs to a GLI server. GLI client looks up a location of a GLI agent by requesting to the GLI home server. The home server forwards to a GIL area server and it replies to the client. A GLI agent periodically registers to a GLI area server.
InternetCAR Project is aiming to construct a global infrastructure of information exchange. This system can provide information retrieved from an automobile. Applications process the information and visualize it for users.
For example, a rain map can be provided by this system. A client gathers information about a location and wiper status of automobiles and maps it. Another application is a traffic congestion map. Using information about location and speed of automobiles, users can know which streets are congested.
Figure 4 shows a screen dump of an example of InternetCAR applications. This application maps the location of a bus with number of passengers.
In November 1997, five InternetCARs became available. One of them was a modified automobile. A dynamo and a DC-AC inverter were added to supply electric power to a computer and so on. This automobile carries a 19-inch rack to install computers and other equipment. The other automobiles were normal automobiles. Each automobile carries a laptop computer which is supplied by an original dynamo. In January 1998, two more InternetCARs were installed.
Figure 5. A modified automobile
Figure 6. Four normal-type InternetCARs
Primary experiments were held to test the developed systems in November 1997. A GLI system, PFS, and other communication systems were tested. Furthermore, a wireless LAN device was added in the testing. Also, a garage with wireless LAN was prepared. Each automobile started out from the garage, was driven around our campus, and returned to the garage. This testing shows us several problems and was almost successful. Table 1 shows necessary times for the changeover of interfaces. As can be seen, it takes a little long to use for interactive applications.
After the testing, we had changed the GLI system. The problem of the GLI system lies in the structure of the server. It was designed as a central system. To support a large number of automobiles, it is changed to a distributed system as described in the section "System Overview."
The current system contains many problems. For example, we have to type "shutdown -h now" to turn off the system. If a user forgets that operation, a file system will crash. Also, there are problems of developed softwares and the architecture. We used IP addresses to specify an automobile. However, IP address space is too small to specify all automobiles in the world. IPv6 is looked to to solve to the problem. Because it is hard to remember an IP address in a IPv6 environment, we are introducing a new identifier to specify an object in the real world.
Phase 2 of this project will be finished in March 1998. In Phase 2, we test software systems in the small infrastructure. Several software systems have already been modified to solve problems. We have to prepare GLI servers for ordinary testing. The report of phase 2 will be available in the spring of 1998.
Phase 3 will start in April 1998. About a hundred automobiles will join in the testing. In this phase, some sample application will be developed to show usability. Furthermore, embedded systems will be designed. It will be discussed which information is necessary. We have a plan to develop a PC-based system to install in a car, which will include a PC, a data-collection board, and GPS. Also, a cellular phone can be connected to the box. Estimation of costs, which includes production costs and communication costs, is an important task of this phase.
Furthermore, computers for automobiles will be available soon. Microsoft Corp. has announced Auto PC. Lucent Technology Inc. has released the Inferno operating system. It is designed for a kind of PDA. These products can be used for our purpose. Unix has some problems. For example, its file system will crash when a computer is turned off without shutdown. It requires a large-sized storage system and a memory. So we plan to introduce the Inferno system. Also, some communication modules, e.g., LWP, will be developed on the Inferno system.
A seamless and transparent Internet access to sensor functions on automobiles as well as the Internet access from an automobile has been achieved. The system was developed by the integration of a new design of architecture for automobiles on the Internet and special mechanisms such as dynamic device switching, GLI and hardware design, as well as with existing mobile Internet technologies. As a result, robust Internet connectivity in an automobile using a rapid switching mechanism was achieved, sensor information in an automobile became available on the Internet, and a standard way to provide location information of an automobile was provided.
This paper described the design and results of phase 2 of the project. Phase 3 will start in April 1998. More than a hundred automobiles will join in the testing. The focus of the phase is application prototype and larger-scale testbeds. The hardware and the computer would be integrated for use as a commercial product. Investigation into the feasibility in the real society and the market also is included in the tasks of this phase. In the year 2000, the number of automobiles in the world is expected to be 737 million. The InternetCAR system prototype achieves 1) the Internet-available space in an automobile, 2) new mobile sensor information on a possible large scale of numbers throughout the world, and 3) a general prototype of mobile and noncomputer nodes in the Internet.