An AutoPC for supporting in-vehicle navigation and location-based multimedia services

摘要

With the rapid progress in the development of wireless technology, the bandwidth of wireless local area network (WLAN) is getting higher and its outdoor transmission distance is also getting longer. It becomes feasible to build a regional communication infrastructure in local areas, e.g., in the campus of an institute or a university, using WLAN. Thus, the design of new generation on-board PCs aims not only to provide conventional navigation services in rural or urban areas, but also to deploy integrated multimedia services in regional areas such as campuses. In this paper we present our design of in-vehicle navigation and location-based multimedia applications in an 802.11b wireless environment. It supports mobile communication based on IETF mobile IP standards with route optimization, smooth handoff, and fast handoff. Furthermore, in order to encourage fast deployment and to reduce system costs, we utilized open technologies in designing our prototype system. The developed AutoPC is a real-time embedded system platform on a single-board PC with GPS, featured by a downsized embedded Linux and a bilingual windows system. The platform supports applications such as in-vehicle navigation, real-time traffic information, MP3 player, and MPEG-4 streaming through mobile IPv4. This prototype is evaluated on a campus-wide 802.11b network, where two neighboring access points are placed about 150 meters apart from each other along the roadside such that a road in the campus is fully covered by 802.11b radio signals. Our preliminary experiments show that the low handoff overhead makes it possible for an in-vehicle AutoPC to run video streaming application seamlessly on the road even when the car speed is up to 50 km/hr. Besides, a 486-level platform is powerful enough to support in-vehicle navigation and to play MP3 smoothly, but a more powerful CPU is required to run our RTP-based MPEG-4 video streaming applications.