Proposal of a Route Optimization Method for a Road-to-Vehicle Wireless System

摘要

The authors are making a study of a road-to-vehicle wireless system as a private-operated wireless system for road control, using a 2.4-GHz-band wireless LAN. In the proposed system, access points (AP) are placed consecutively on the highway, and AP-to-vehicle communications and AP-to-AP forwarding transmission are performed by wireless LAN. It has the feature that a less expensive system can be constructed. The spanning-tree protocol (STP) is applied to the bridge placed in each AP, which improves the reliability of the network. In STP, there occur sections in which the communications route is not optimal for vehicle-to-vehicle communications. To deal with this problem, this paper proposes a route optimization method in which route notification messages are exchanged between adjacent bridges and the communications route distance between vehicles is minimized. The performance is evaluated by using a bridge implementing the proposed method and a wireless LAN, and it is verified that communications performance measures such as the delay time and throughput are improved compared to the conventional STP.