A Vehicle-Approach Alert System Based on the Neighbor Discovery Protocol for Pedestrian Safety

This paper proposes a system that alerts a pedestrian about an approaching vehicle to be cautioned based on the neighbor discovery protocol, in which the pedestrian’s device repeatedly broadcasts a specific beacon, called the advertising beacon, triggered by a pedestrian’s action and the moving vehicle in the vicinity sends the response beacon when it receives the advertising beacon. The pedestrian’s device emits an alert, e.g., with sound, as a consequence of receiving the response beacon. The feasibility of the proposed system is demonstrated by a field experiment with the prototype device using IEEE 802.15.4g as the communication standard of the physical layer for the beacon packet. In addition, the current consumption of the prototype pedestrian’s device is measured, and the proposed system is compared to two other types of methods from the viewpoint of the device battery life. The results show that the neighbor discovery protocol contributes to prolonging the battery life of the pedestrian’s device since the receiver can open the receiver window only while it waits for the response beacon, compared to the full-listening method, in which the pedestrian’s device must open the receiver window all the time.