Shoji Fukuzawa

Enhanced Functions of 802.11 Protocol for Adaptation to Communications between High Speed Vehicles and Infrastructures

There are many researches on the mobile network based on IEEE 802.11 wireless devices. While wireless LAN devices are commonly used, they have been originally designed for office use and have no support for high mobility. Hence, the association establishment (the channel scanning of mobile nodes and the auth/association frame exchange between mobile nodes and access points) and the handoff often fails when we try to utilize the device for the communication between high speed vehicles and infrastructures. We proposed the method that realizes rapid association establishment and optimized handoffs to solve the problems in a compatible form with 802.11 protocol. We realized the proposed method by modifying the standard 802.11 specification of client side. On the evaluation in the actual environment, we showed better thoroughput with the proposed method than the one with the standard 802.11 specification.

Development of Vehicular Communication (WAVE) System for Safety Applications

These years, there has been much research and development activity in safety service for ITS (Intelligent Transports System) globally because fatal accidents have been increasing rapidly according to spread of vehicles. In order to decrease traffic accident, cooperation between vehicle and infrastructure (C2I: Car to Infrastructure) and between cars (C2C: Car to Car) attracts much attention. In this paper, we introduce WAVE (Wireless Access in Vehicular Environment) technology that is under standardization for C2I and C2C communication as IEEE802.11p and IEEE P1609. Then we present developing WAVE device with dual lip wireless device. With dual device, WAVE system is expected to provide stable operation, reliable communication and higher performance. For the purpose of validity of WAVE system, we have developed typical safety application systems of crossroad collision avoidance scenario and front-tail collision avoidance scenario, and show evaluation plan.

Performance measurement of mobile ad hoc network for application to Internet-ITS (intelligent transportation system)

We evaluated the performance of an ad hoc network in a mobile environment in order to access its feasibility as an infrastructure for vehicle-to-Internet communication services. To realize this kind of service. The infrastructure should provide wide range where the service is available. We expected that by using an ad hoc network, spatial service range, connection time to the access point while driving, and amount of data transferred from the access point would be better than in existing public wireless LAN services. In the experiment, three cars acted as mobile nodes, and we measured the connection time to the access point and the amount of data that could be given via the access point. The result confirms the feasibility of using an ad hoc network as an infrastructure for vehicle-to-Internet communication services.