Method for detecting synchronization deviation between communication stations

Patent metadata

Field	Value
Publication number	US-10945223-B2
Application number	US-201716076716-A
Country	US
Kind code	B2
Filing date	Jan 18, 2017
Priority date	Feb 10, 2016
Publication date	Mar 9, 2021
Grant date	Mar 9, 2021

Abstract

The time of transmission and reception between stations A and B is exchanged, and any deviation in time is calculated in a corresponding manner in the stations. Using the transmission time TXA from station A to B, the transmission time TYB from station B to A, the time TXB of a clock at station B in a transmission from station A to station B, and the clock time TYA at station A in a transmission from station B to A, the following are measured in sequence: 1) station A records the time TXA at which TXA and TYA were transmitted, 2) station B measures the time TXB at which TXA and TYA were received, 3) station B records the time TYB at which TXB and TYB were transmitted, and 4) station A measures the time TYA at which TXB and TYB were received, the transfer time between stations A and B being derived at each station on the basis of the average of the increase ΔTXB-A from TXA to TXB and the increase ΔTYA-B from TYB to TYA, or the deviation in time for a transfer between stations A and B being determined by subtracting the increase ΔTXB-A from the transfer time. The transmission time TXA from station A to B may also be measured using a reflection signal from a transmission terminal.

First claim

The invention claimed is:

1. A method for detecting a synchronization deviation between communication stations, the method being a method for detecting, in first and second communication stations selected from among two or more communication stations that are connected to each other via a communication method to be capable of communicating with each other, a deviation in time between first time information that is transmitted from a transmitter (X) of the first communication station (A) and received by the first communication station and by the second communication station (B) and second time information that is transmitted from a transmitter (Y) of the second communication station and received by the first communication station and by the second communication station, the communication stations each clocking time in a corresponding manner, wherein the first time information contains first integrated phase information or first phase time information, and the second time information contains second integrated phase information or second phase time information, and
transmitting predetermined empty information in a case of transmission of undetermined time information among transmission time information (TXA) from the first communication station to the second communication station, transmission time information (TYB) from the second communication station to the first communication station, reception time (TXB) of a clock at the second communication station in a transmission from the first communication station to the second communication station, and reception time (TYA) of a clock at the first communication station in a transmission from the second communication station to the first communication station, wherein TXA is a first phase time, TXB is a second phase time, TYA is a third phase time and TYB is a fourth phase time, the method comprising, in a process including:
(1) a step in which the first communication station transmits T 1 XA and T 1 YA from among a set containing T 1 XA, T 1 XB and T 1 YA and records the transmission time T 2 XA,
(2) a step in which the second communication station receives T 1 XA and T 1 YA and measures and records the reception time T 2 XB,
(3) a step in which the second communication station transmits T 2 XB and T 1 YB and records the transmission time T 2 YB,
(4) a step in which the first communication station receives T 2 XB and T 1 YB and measures and records the reception time T 2 YA, for a set of input values of T 1 XA, T 1 XB, T 1 YA, and T 1 YB, and for a set containing T 2 XA, T 2 XB and T 2 YA, and:
deriving, at the first communication station, a transfer time of signal between the first communication station and the second communication station on the basis of an arithmetic mean of an increase (ΔTXB-A) from T 1 XA to T 1 XB and an increase (ΔTYA-B) from T 1 YB to T 1 YA; or
determining the deviation in time between the first communication station and the second communication station by subtracting the increase (ΔTXB-A) from the transfer time or by subtracting the transfer time from the increase (ΔTYA-B).

2. The method for detecting a synchronization deviation between communication stations according to claim 1 , wherein, in the first communication station or the second communication station, by using an offset phase difference generated from each reception point to a phase-difference measurement point, the received phase difference is corrected.

3. The method for detecting a synchronization deviation between communication stations according to claim 1 , wherein communication between the first communication station and the second communication station is wireless communication, and the first communication station signal or the second communication station signal is a carrier wave that has been modulated by using information containing the phase difference ΦXB or ΦYA.

4. The method for detecting a synchronization deviation between communication stations according to claim 3 , wherein the wireless communication between the first communication station and the second communication station is performed by using a common frequency channel in a time shared manner.

5. The method for detecting a synchronization deviation between communication stations according to claim 3 , wherein, in the wireless communication between the first communication station and the second communication station, a frequency channel in downstream communication from the first communication station to the second communication station and a frequency channel in upstream communication from the second communication station to the first communication station are different, and the downstream communication and the upstream communication are performed in time slots that are partially overlapped with each other.

6. The method for detecting a synchronization deviation between communication stations according to claim 1 , wherein,
the detection of a synchronization deviation between two or more communication stations includes categorizing the second communication station, for which time synchronization with the predetermined first communication station has been completed, into a first communication station group together with the predetermined first communication station, and categorizing a communication station group, for which time synchronization is yet to be completed, into a second communication station group, and
sequentially performing time synchronization between communication stations for a pair of the first communication station and the second communication station according to an order,
the order being feasible by a method for determining the order of time synchronization by performing the following operation until there is no communication station categorized into the second communication station group, if a communication station selected from the second communication station group
(1) is capable of communicating with a communication station belonging to the first communication station group, the category of the selected communication station is transferred from the second communication station group to the first communication station group, or
(2) is not capable of communicating with a communication station belonging to the first communication station group, a new second communication station is selected from the second communication station group, and the process returns to (1).

7. The method for detecting a synchronization deviation between communication stations according to claim 1 , wherein,
the detection of a synchronization deviation between two or more communication stations includes
categorizing a communication station that is determined as being capable of communicating with the predetermined first communication station into a candidate first communication station group together with the first communication station and categorizing a communication station that is not determined as being capable of communicating into a candidate second communication station group,
selecting one of orders that are feasible by a method for determining the order of a pair of communication stations for applying the method for detecting a synchronization deviation between communication stations by performing the following operation until there is no communication station categorized into the candidate second communication station group,
for a new communication station selected from the candidate second communication station group,
(1) if communication with a communication station belonging to the candidate first communication station group is possible, the category of the selected communication station is transferred from the candidate second communication station group to the candidate first communication station group, or
(2) if communication with a communication station belong

Assignees

• Nat Inst Inf & Comm Tech

Inventors

• Shiga Nobuyasu
• Inoue Masugi
• Yasuda Satoshi
• KIDO Kohta

Classifications

• G04G7/00

  Synchronisation (radio-controlled time-pieces G04R) · CPC title

• H04L7/00

  Arrangements for synchronising receiver with transmitter {(synchronisation of generators of electric oscillations or pulses H03L7/00)} · CPC title

• H04W56/001 Primary

  Synchronization between nodes · CPC title

• G04G7/02

  by radio · CPC title

• H04W84/20

  Leader-follower arrangements · CPC title