CN-121995314-A - Method and device for ONU ranging by utilizing wavelength dispersion difference

Abstract

The disclosure relates to the technical field of optical communication low-delay, in particular to a method and a device for ONU ranging by utilizing wavelength dispersion difference. And calculating the proportional coefficient beta λ1 λ2 by the signal transmission time difference delta t3 caused by the dispersion of the ONU on the initial line and the distance L measured by the PON standard ranging flow, and calculating the distance of the ONU on the subsequent line by the proportional coefficient beta λ1 λ2 and the signal transmission time difference delta t3 caused by the dispersion of the ONU on the subsequent line. The method and the device fully utilize the characteristics of different downlink wavelength differences of different international PONs, such that the dispersion difference is large, and the downlink data arrival time difference is caused, so as to realize ranging of ONU and avoid the silence window of TDM PON.

Inventors

• LIU XINFENG
• LI TAO
• SHEN QIONGXIA
• CHANG YUGUANG
• QIN YUPENG

Assignees

• 烽火通信科技股份有限公司

Dates

Publication Date

20260508

Application Date

20241104

Claims (15)

1. 1. A method for ONU ranging using wavelength dispersion difference, the method comprising: Calculating a proportionality coefficient beta λ1λ2 through a signal transmission time difference delta t3 caused by the dispersion of the ONU which is initially on line and a distance L measured by a PON standard ranging flow; And the distance between the ONU on the subsequent line is calculated by the ONU on the subsequent line through the proportionality coefficient beta λ1λ2 and the signal transmission time difference delta t3 caused by the chromatic dispersion.
2. 2. The method for ONU ranging using wavelength dispersion difference according to claim 1, wherein, Calculating a proportionality coefficient beta λ1λ2 by a signal transmission time difference delta t3 caused by the dispersion of the ONU which is initially on line and a distance L measured by a PON standard ranging flow, wherein the method comprises the following steps: When the first ONU is on line, calculating L and delta t3 through a standard ranging flow, and then correcting a beta λ1λ2 parameter value according to calculation, wherein beta λ1λ2 =L/delta t3; The Δt3 calculation includes: The ONU detects the synchronization code of wavelength 1, and then enters the presynchronization state, confirms and acquires the frame boundary time of wavelength 1 through the frame boundary of wavelength 1, acquires the frame boundary time of wavelength 2 by referring to the operation of wavelength 1, calculates the frame boundary time difference delta t2 between the wavelength 1 and the wavelength 2 to enter the dispersion ranging state, calculates delta t2 = t dA Collecting and recovering -t 50Gd Collecting and recovering according to the frame header received by 50Gd and the frame header received by dA, extracts delta t1 and beta λ1λ2 parameters from the data frame payload broadcast by the OLT, and calculates delta t3 = delta t 2-delta t1 generated by different speeds of light in the optical fiber due to chromatic dispersion.
3. 3. The method for ONU ranging using wavelength dispersion difference according to claim 1, wherein, The distance of the ONU on the subsequent line is calculated by the ONU on the subsequent line through the proportionality coefficient beta λ1λ2 and the signal transmission time difference delta t3 caused by the chromatic dispersion, and the method comprises the following steps: The ONU monitors the data frame of the OLT, the frame header sent by 50Gd and the frame header sent by dA reach wavelength 1 firstly and then reach wavelength 2, the ONU searches the wavelength 1 synchronous code, and enters a presynchronization state after the frame synchronous code of the wavelength 1 is found, the wavelength 1 frame boundary time is confirmed and obtained through the wavelength 1 frame boundary, the wavelength 2 frame boundary time is obtained by referring to the wavelength 1 operation, the frame boundary time difference delta t2 between the wavelength 1 and the wavelength 2 enters a dispersion ranging state, the ONU MAC calculates delta t2 = t dA Collecting and recovering -t 50Gd Collecting and recovering according to the frame header received by 50Gd and the frame header received by dA, and extracts delta t1 and beta λ1λ2 parameters in the data frame payload broadcast by the OLT, and the ONU calculates delta t3 = delta t 2-delta t1 which are generated by different light speeds in the optical fibers due to chromatic dispersion; And the ONU sets the burst data sending parameter through the distance L to finish the ranging without the silence window.
4. 4. The method for ONU ranging using wavelength dispersion difference according to claim 1, wherein, A signal transmission time difference caused by dispersion of an ONU, comprising: In the 50G PON ONU, the optical module increases the reception of the wavelength λ dA for ranging, and the wavelength λ dA for ranging may receive only XG (S) -PON frame header for timing calculation.
5. 5. The method for ONU ranging using wavelength dispersion difference according to claim 1, wherein, A signal transmission time difference caused by dispersion of an ONU, comprising: In the 50G PON ONU, the optical module increases transmission and reception of wavelength λ dA for ranging, and wavelength λ dA is used for performing dispersion ranging timing and receiving data.
6. 6. The method for ONU ranging using wavelength dispersion difference according to claim 1, wherein, A signal transmission time difference caused by dispersion of an ONU, comprising: In a 50G PON ONU, an optical module increases transmission and reception of a wavelength λ dA for ranging, receives a pulse of a wavelength λ dA , and transmits the pulse to a MAC of the 50G-PON ONU for timing calculation.
7. 7. The method for ONU ranging using wavelength dispersion difference according to claim 1, wherein, A signal transmission time difference caused by dispersion of an ONU, comprising: In the 50G PON ONU, the optical module increases the transmission and reception of wavelength λ dA for ranging, and simultaneously receives 1342nm data and wavelength λ dA data, which are the same, and corrects the data of two different channels.
8. 8. A transmission method for ONU ranging using a wavelength dispersion difference, characterized in that a method for ONU ranging using a wavelength dispersion difference according to any one of claims 1 to 7 is employed, the method comprising: In the 50G PON OLT, a MAC module processes a data frame and a protocol, an optical module transmits and receives a physical layer, a transmission lambda 50Gd is a downlink transmission wavelength 1342nm of 50G, and the optical module receives a lambda 50Gd of 1342 nm; the optical module adds a new transceiver of wavelength lambda dA for ranging.
9. 9. The transmission method for ONU ranging using wavelength dispersion difference according to claim 8, wherein, Further comprises: OLT MAC calculates Δt1=t dA Hair brush -t 50Gd Hair brush from the 50 Gd-transmitted frame header and the dA-transmitted frame header time and broadcasts the Δt1 and β λ1λ2 parameters in the data frame payload.
10. 10. The transmission method for ONU ranging using wavelength dispersion difference according to claim 8, wherein, The optical module adds a new transceiver of wavelength lambda dA for ranging, comprising: The wavelength is selected to 1577nm, the downlink wavelength of XG (S) -PON is reused, the MAC of XG (S) -PON is reused by the data transmission frame processing corresponding to the MAC of lambda dA in the 50G PON OLT, the lambda dA transmits the XG (S) -PON data existing in the current network, and the XG (S) -PON frame head is used for timing calculation of ranging.
11. 11. The transmission method for ONU ranging using wavelength dispersion difference according to claim 8, wherein, The optical module adds a new transceiver of wavelength lambda dA for ranging, comprising: And the MAC in the 50G PON OLT is additionally provided with a lambda dA data transmission channel, and lambda dA transmits the downlink data of the 50G-PON.
12. 12. The transmission method for ONU ranging using wavelength dispersion difference according to claim 8, wherein, The optical module adds a new transceiver of wavelength lambda dA for ranging, comprising: Lambda dA in 50G PON OLT transmits a synchronous pulse through MAC of 50G-PON at the same time of transmitting frame synchronization of wavelength 1342nm, lambda dA only transmits pulse and does not transmit data.
13. 13. The transmission method for ONU ranging using wavelength dispersion difference according to claim 8, wherein, The optical module adds a new transceiver of wavelength lambda dA for ranging, comprising: the wavelength selects the downlink wavelength which is normally transmitted at 50Gbps and is not used by the system; The data transmission frame corresponding to the MAC of lambda dA in the 50G PON OLT shares the MAC of the wavelength 1342nm of the 50G-PON, and the transmission data of lambda dA is identical with the data of 1342 nm.
14. 14. An apparatus for ONU ranging using a wavelength dispersion difference, wherein the ONU ranging method using a wavelength dispersion difference according to any one of claims 1 to 7 comprises an initial unit and a ranging unit; The initial unit is used for calculating a proportionality coefficient beta λ1λ2 through a signal transmission time difference delta t3 caused by the dispersion of the ONU which is initially on line and a distance L measured by a PON standard ranging flow; and the ranging unit is used for calculating the distance of the ONU on the subsequent line through the proportionality coefficient beta λ1λ2 and the signal transmission time difference delta t3 caused by the chromatic dispersion.
15. 15. A transmitting apparatus for ONU ranging using wavelength dispersion difference, characterized in that, a transmitting method for ONU ranging using wavelength dispersion difference according to any of claims 8-13 is employed, In the 50G PON OLT, a MAC module processes a data frame and a protocol, an optical module transmits and receives a physical layer, a transmission lambda 50Gd is a downlink transmission wavelength 1342nm of 50G, and the optical module receives a lambda 50Gd of 1342 nm; the optical module adds a new transceiver of wavelength lambda dA for ranging.

Description

Method and device for ONU ranging by utilizing wavelength dispersion difference Technical Field The disclosure relates to the technical field of optical communication low-delay, in particular to a method and a device for ONU ranging by utilizing wavelength dispersion difference. Background The passive optical network PON technology is a point-to-multipoint optical fiber access technology, and is composed of an OLT at a office side, ONUs at a user side, and ODNs. The traditional TDM PON system adopts a broadcasting technology for downlink data flow and a TDMA technology for uplink data flow so as to solve the multiplexing problem of signals of each direction of multiple users. In the TDM PON system, when a new Optical network unit (OpticalNetworkUnit, ONU) is added to the network, an activation and ranging process is required in order to be able to be discovered and managed by an Optical line terminal (Optical LINE TERMINAL, OLT). If no special processing is performed, the activation and ranging process has a certain probability of possibly generating collision and collision with uplink normal data transmission. In order to avoid collision, the conventional processing method is that the OLT suspends bandwidth allocation to the ONUs, and the ONUs will internally buffer data to be transmitted in a period of time, not transmit the data, but leave the period of time for the newly added ONUs to activate and ranging, and transmit the buffered data after the period of time, which is called a silence window. According to the protocol standard ITU g.984 analysis, silence windows typically result in delays and jitter in network transmissions exceeding 250 microseconds. The emerging services such as industrial PON, immersive interactive XR, etc. put new requirements on network delay jitter, in order to reduce the delay and jitter of the network, a special activation wavelength is put forward in the ITU g.9804.2 standard to eliminate the silence window, and the OLT performs the activation and ranging process by adding a new uplink wavelength or using the uplink wavelength of the previous-generation PON, so as to avoid the silence window in the uplink traffic. The extra wavelength requires the ONU to add an extra burst LD, which has some drawbacks in terms of cost, power consumption, etc. In view of the foregoing, a technical solution for avoiding the PON silence window without increasing the cost or power consumption is needed. Disclosure of Invention In view of the above problems, the present disclosure provides a method and apparatus for performing ONU ranging using a wavelength dispersion difference, which implement ONU ranging by using a characteristic of a downstream data arrival time difference caused by a downstream wavelength dispersion difference, thereby performing PON silence window avoidance. In a first aspect, a method for ONU ranging using wavelength dispersion difference, the method comprising: Calculating a proportionality coefficient beta λ1λ2 through a signal transmission time difference delta t3 caused by the dispersion of the ONU which is initially on line and a distance L measured by a PON standard ranging flow; And the distance between the ONU on the subsequent line is calculated by the ONU on the subsequent line through the proportionality coefficient beta λ1λ2 and the signal transmission time difference delta t3 caused by the chromatic dispersion. Further, calculating the proportionality coefficient β λ1λ2 by the signal transmission time difference Δt3 caused by the dispersion of the ONU initially on line and the distance L measured by the PON standard ranging procedure includes: When the first ONU is on line, calculating L and delta t3 through a standard ranging flow, and then correcting a beta λ1λ2 parameter value according to calculation, wherein beta λ1λ2 =L/delta t3; The Δt3 calculation includes: The ONU detects the synchronization code of wavelength 1, and then enters the presynchronization state, confirms and acquires the frame boundary time of wavelength 1 through the frame boundary of wavelength 1, acquires the frame boundary time of wavelength 2 by referring to the operation of wavelength 1, calculates the frame boundary time difference delta t2 between the wavelength 1 and the wavelength 2 to enter the dispersion ranging state, calculates delta t2 = t dA Collecting and recovering -t50Gd Collecting and recovering according to the frame header received by 50Gd and the frame header received by dA, extracts delta t1 and beta λ1λ2 parameters from the data frame payload broadcast by the OLT, and calculates delta t3 = delta t 2-delta t1 generated by different speeds of light in the optical fiber due to chromatic dispersion. Further, the calculating the distance between the ONU on the subsequent line according to the proportionality coefficient β λ1λ2 and the signal transmission time difference Δt3 caused by the chromatic dispersion includes: The ONU monitors the data frame of the OLT, the fr