# US 2020/0099444 A1 · Delay measurement method and station > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0099444 A1 - Document ID: US20200099444A1 - Status: Published application - Kind: A1 - Application number: 16/696,755 - Filed: 2019-11-26 - Published: 2020-03-26 - Earliest claimed: 2017-05-31 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: Bangxu LI - Web page: https://patentgrep.com/patent/US20200099444A1 ## CPC - H04B 10/077: using a supervisory or additional signal - H04B 10/0775: {Performance monitoring and measurement of transmission parameters} - H04B 10/0795: {Performance monitoring; Measurement of transmission parameters} - H04Q 11/0005: {Switch and router aspects} - H04Q 11/0062: {Network aspects} - H04Q 2011/0045: {Synchronisation} - H04Q 2011/0073: {Provisions for forwarding or routing, e.g. lookup tables} - H04Q 2213/13172: Supervisory signals - H04B: TRANSMISSION - H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W) ## Abstract Methods and stations for transmission delay measurements are disclosed. The method includes controlling, by a first station, an optical path selector to work in a first state, and selecting, by the first station, a first fiber to send a first OSC signal to a second station, where the first OSC signal includes a first time stamp. The method further includes controlling, by the first station, the optical path selector to work in a second state, and selecting, by the first station, the first fiber to receive a second OSC signal from the second station at a second receiving moment, where the second OSC signal includes a second time stamp. The method further includes calculating, by the first station, a unidirectional transmission delay between the first station and the second station based on a first sending moment, a first receiving moment, a second sending moment, and the second receiving moment. ## Claims ### Claim 1 A method of measuring a transmission delay between stations, comprising: controlling, by a first station, an optical path selector to work in a first state, selecting, by the first station, a first fiber to send a first optical supervisory channel (OSC) signal to a second station, wherein the first OSC signal comprises a first time stamp, and the first time stamp indicates a first sending moment at which the first station sends the first OSC signal; controlling, by the first station, the optical path selector to work in a second state, selecting, by the first station, the first fiber to receive a second OSC signal from the second station at a second receiving moment, wherein the second OSC signal comprises a second time stamp, the second time stamp indicates a first receiving moment at which the second station receives the first OSC signal and a second sending moment at which the second station sends the second OSC signal, and a difference between a value of a wavelength used by the first OSC signal and a value of a wavelength used by the second OSC signal is less than a preset value; and calculating, by the first station, a unidirectional transmission delay between the first station and the second station based on the first sending moment, the first receiving moment, the second sending moment, and the second receiving moment. ### Claim 2 (depends on 1) The method according to claim 1, wherein the difference between the value of the wavelength used by the first OSC signal and the value of the wavelength used by the second OSC signal is 0. ### Claim 3 (depends on 1) The method according to claim 1, wherein the unidirectional transmission delay is a half of a difference between a first operation value and a second operation value, the first operation value is a difference between the second receiving moment and the first sending moment, and the second operation value is a difference between the second sending moment and the first receiving moment. ### Claim 4 (depends on 1) The method according to claim 1, further comprising: after calculating the unidirectional transmission delay between the first station and the second station based on the first sending moment, the first receiving moment, the second sending moment, and the second receiving moment, sending, by the first station, the unidirectional transmission delay to the second station. ### Claim 5 (depends on 1) The method according to claim 1, further comprising: after selecting the first fiber to send the first OSC signal to the second station, receiving, by the first station, an acknowledgement message from the second station, wherein the acknowledgement message is used to indicate that the second station has received the first OSC signal. ### Claim 6 (depends on 1) The method according to claim 1, wherein the optical path selector is a 2×2 optical switch. ### Claim 7 A method of measuring a transmission delay between stations, comprising: controlling, by a second station, an optical path selector to work in a first state, selecting, by the second station, a first fiber to receive a first optical supervisory channel (OSC) signal from a first station, wherein the first OSC signal comprises a first time stamp, and the first time stamp indicates a first sending moment at which the first station sends the first OSC signal; and controlling, by the second station, the optical path selector to work in a second state, selecting, by the second station, the first fiber to send a second OSC signal to the first station, wherein the second OSC signal comprises a second time stamp, the second time stamp indicates a first receiving moment at which the second station receives the first OSC signal and a second sending moment at which the second station sends the second OSC signal, and a difference between a value of a wavelength used by the first OSC signal and a value of a wavelength used by the second OSC signal is less than a preset value. ### Claim 8 (depends on 7) The method according to claim 7, wherein the difference between the value of the wavelength used by the first OSC signal and the value of the wavelength used by the second OSC signal is 0. ### Claim 9 (depends on 7) The method according to claim 7, wherein a unidirectional transmission delay is a half of a difference between a first operation value and a second operation value, the first operation value is a difference between a second receiving moment at which the first station receives the second OSC signal and the first sending moment, and the second operation value is a difference between the second sending moment and the first receiving moment. ### Claim 10 (depends on 7) The method according to claim 7, further comprising: after selecting the first fiber to send the second OSC signal to the first station, receiving, by the second station, the unidirectional transmission delay sent by the first station. ### Claim 11 (depends on 10) The method according to claim 10, further comprising: after receiving, by the second station, the unidirectional transmission delay sent by the first station, synchronizing, by the second station, a time of the second station with a time of the first station based on the unidirectional transmission delay and the time of the first station. ### Claim 12 (depends on 7) The method according to claim 7, wherein controlling, by the second station, the optical path selector to work in the second state comprises: controlling, by the second station based on a change of an optical power on the first fiber, the optical path selector to work in the second state. ### Claim 13 (depends on 7) The method according to claim 7, further comprising: after selecting the first fiber to receive the first OSC signal from the first station, sending, by the second station, an acknowledgement message to the first station, wherein the acknowledgement message is used to indicate that the second station has received the first OSC signal. ### Claim 14 (depends on 7) The method according to claim 7, wherein the optical path selector is a 2×2 optical switch. ### Claim 15 A first station, comprising: a controller; an optical path selector connected to the controller; and a fiber interface unit connected to the optical path selector; wherein the controller is configured to control the optical path selector to work in a first state, the fiber interface unit is configured to select a first fiber to send a first optical supervisory channel (OSC) signal to a second station, wherein the first OSC signal comprises a first time stamp, and the first time stamp indicates a first sending moment at which the first station sends the first OSC signal, wherein the controller is further configured to control the optical path selector to work in a second state, the fiber interface unit is configured to select the first fiber to receive a second OSC signal from the second station at a second receiving moment, wherein the second OSC signal comprises a second time stamp, the second time stamp indicates a first receiving moment at which the second station receives the first OSC signal and a second sending moment at which the second station sends the second OSC signal, and a difference between a value of a wavelength used by the first OSC signal and a value of a wavelength used by the second OSC signal is less than a preset value, and wherein the controller is further configured to calculate a unidirectional transmission delay between the first station and the second station based on the first sending moment, the first receiving moment, the second sending moment, and the second receiving moment. ### Claim 16 (depends on 15) The first station according to claim 15, wherein the difference between the value of the wavelength used by the first OSC signal and the value of the wavelength used by the second OSC signal is 0. ### Claim 17 (depends on 15) The first station according to claim 15, wherein the unidirectional transmission delay is a half of a difference between a first operation value and a second operation value, the first operation value is a difference between the second receiving moment and the first sending moment, and the second operation value is a difference between the second sending moment and the first receiving moment. ### Claim 18 A second station, comprising: a controller; an optical path selector connected to the controller; and a fiber interface unit connected to the optical path selector; wherein the controller is configured to control the optical path selector to work in a first state, the fiber interface unit is configured to select a first fiber to receive a first optical supervisory channel (OSC) signal from a first station, wherein the first OSC signal comprises a first time stamp, and the first time stamp indicates a first sending moment at which the first station sends the first OSC signal, and wherein the controller is further configured to control the optical path selector to work in a second state, the fiber interface unit is configured to select the first fiber to send a second OSC signal to the first station, wherein the second OSC signal comprises a second time stamp, the second time stamp indicates a first receiving moment at which the second station receives the first OSC signal and a second sending moment at which the second station sends the second OSC signal, and a difference between a value of a wavelength used by the first OSC signal and a value of a wavelength used by the second OSC signal is less than a preset value. ### Claim 19 (depends on 18) The second station according to claim 18, wherein the difference between the value of the wavelength used by the first OSC signal and the value of the wavelength used by the second OSC signal is 0. ### Claim 20 (depends on 18) The second station according to claim 18, wherein the unidirectional transmission delay is a half of a difference between a first operation value and a second operation value, the first operation value is a difference between a second receiving moment at which the first station receives the second OSC signal and the first sending moment, and the second operation value is a difference between the second sending moment and the first receiving moment.