Low-power V2M communication system with fast network association capability

This paper proposes a low power Vehicular-to-Machine (V2M) communication system consisting of crowd servers, moving vehicles and low-power fixed roadside devices. In order to save energy of roadside devices, it employs an enhanced ZigBee protocol with fast network association and switching capability. The vehicles can collect information from various types of roadside devices and process them for their own, as well as uploading some of them to corresponding servers for public use. In the system, a roadside device, playing role of the ZigBee end device, detects a vehicular station (VS) by hearing its beacon signal that requests necessary types of information. The device then associates the personal area network (PAN) that is formed by the VS and repeats the association and disconnection for different PANs so that it can send information to all requesting VSs. With current ZigBee protocol, however, it is difficult for the devices to handover between PANs passing by at high speed. In order to enable smooth and fast network association, we propose a fast PAN association / handover algorithm that refers to PAN subscription history and receiving power of beacon. It is confirmed via computer simulations that the proposed method enables faster network association and remarkably improves information delivery rate compared with the original ZigBee protocol.