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1. (WO2018123857) SENSING SYSTEM AND TIME SYNCHRONIZATION METHOD

Pub. No.:    WO/2018/123857    International Application No.:    PCT/JP2017/046111
Publication Date: Fri Jul 06 01:59:59 CEST 2018 International Filing Date: Sat Dec 23 00:59:59 CET 2017
IPC: G08C 15/06
G04G 7/00
H04L 7/00
H04Q 9/00
Applicants: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
日本電信電話株式会社
Inventors: MATSUNAGA,Kenichi
松永 賢一
OSHIMA,Shoichi
大嶋 尚一
MUSA,Ahmed
ムサ アハマド
Title: SENSING SYSTEM AND TIME SYNCHRONIZATION METHOD
Abstract:
In the present invention, when a data collection terminal slave device (2) receives a dummy packet the data collection terminal slave device appends to a return packet a timestamp indicating the reception time of the dummy packet and a timestamp indicating the transmission time of the return packet, and then transmits the return packet to a data collection terminal master device (3). When a time synchronization process is carried out the data collection terminal master device (3) transmits a dummy packet to the data collection terminal slave device (2), and when the return packet is received the data collection terminal master device calculates a synchronization deviation time between the data collection terminal master device (3) and the data collection terminal slave device (2) and a propagation delay time between the data collection terminal master device (3) and the data collection terminal slave device (2), on the basis of the transmission time of the dummy packet and the reception time of the return packet, and the reception time of the dummy packet and transmission time of the return packet, which are obtained from the timestamp of the return packet.