US 11,750,358 B2
Time transmission device and transmission method
Masahiro Nakagawa, Musashino (JP); Kaoru Arai, Musashino (JP); Hiroki Sakuma, Musashino (JP); and Shunichi Tsuboi, Musashino (JP)
Assigned to Nippon Telegraph and Telephone Corporation, Tokyo (JP)
Appl. No. 17/431,576
Filed by Nippon Telegraph and Telephone Corporation, Tokyo (JP)
PCT Filed Feb. 13, 2020, PCT No. PCT/JP2020/005637
§ 371(c)(1), (2) Date Aug. 17, 2021,
PCT Pub. No. WO2020/170947, PCT Pub. Date Aug. 27, 2020.
Claims priority of application No. 2019-029897 (JP), filed on Feb. 21, 2019.
Prior Publication US 2022/0140991 A1, May 5, 2022
Int. Cl. H04B 10/07 (2013.01); H04L 7/00 (2006.01); H04B 10/077 (2013.01)
CPC H04L 7/0075 (2013.01) [H04B 10/0775 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A time transmission device including an optical transmission unit connected to any node position on a transmission path in which bidirectional optical communication in downstream and upstream directions is possible, and a time synchronization unit configured to transmit, between a plurality of nodes, time information for correcting a time deviation between the plurality of nodes, the time transmission device comprising:
a delay measurement signal generation unit configured to simultaneously transmit a plurality of signals having different wavelengths as delay measurement signals to the transmission path;
a delay management unit configured to determine a delay value reflecting a propagation delay calculated based on an arrival time difference between a plurality of wavelengths in the delay measurement signals received from another node of the plurality of nodes via the transmission path, and determine a waiting time amount based on the delay value and the propagation delay;
a delay value notification unit configured to notify the other node of the plurality of nodes of the delay value;
a variable delay unit configured to output signals received from the other node of the plurality of nodes via the transmission path with a delay of the waiting time amount;
an intermittent signal generation unit configured to: (i) generate an optical intermittent signal obtained by periodically selecting and multiplexing at least any of the time information, the delay measurement signal, and desired communication information using one or more of a plurality of wavelengths and (ii) reflect a difference in priority by the plurality of signals to be transmitted and buffer and multiplex a plurality of types of input signals; and
a signal identification unit configured to extract a desired multiplexed signal from the optical intermittent signals included in a received signal.