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EP-4040746-B1 - PASSIVE OPTICAL NETWORK-BASED COMMUNICATION METHOD, RELATED DEVICE, AND SYSTEM

EP4040746B1EP 4040746 B1EP4040746 B1EP 4040746B1EP-4040746-B1

Inventors

  • WU, Xuming
  • LIU, DEKUN
  • NIE, SHIWEI

Dates

Publication Date
20260506
Application Date
20200825

Claims (13)

  1. A communication method based on a passive optical network, wherein the passive optical network comprises an optical line terminal, OLT, and a plurality of optical network units, ONUs, the OLT and the ONU communicate with each other by using at least one downstream wavelength path and a plurality of upstream wavelength paths, the plurality of ONUs comprise an activated ONU, and the method comprises: sending (301), by the OLT, a first downstream frame to the activated ONU by using the at least one downstream wavelength path, wherein the first downstream frame comprises a first path identifier used to identify a first upstream wavelength path, and the first upstream wavelength path is one of the plurality of upstream wavelength paths; and receiving (304), by the OLT, upstream service data from the activated ONU by using the first upstream wavelength path; wherein the plurality of ONUs further comprise a to-be-activated ONU, and the method further comprises: sending (401), by the OLT, a second downstream frame to the to-be-activated ONU by using the at least one downstream wavelength path, wherein the second downstream frame comprises a second path identifier used to identify a second upstream wavelength path, and the first upstream wavelength path and the second upstream wavelength path in the plurality of upstream wavelength paths do not interfere with each other; receiving (404), by the OLT, a registration request message from the to-be-activated ONU by using the second upstream wavelength path; and completing (405), by the OLT, ranging and registration on the to-be-activated ONU based on the registration request message.
  2. The method according to claim 1, wherein that the first upstream wavelength path and the second upstream wavelength path in the plurality of upstream wavelength paths do not interfere with each other is specifically that: if the first upstream wavelength path and the second upstream wavelength path are located in a same fiber, a wavelength corresponding to the first upstream wavelength path and a wavelength corresponding to the second upstream wavelength path are different from each other; or the first upstream wavelength path and the second upstream wavelength path are located in different fibers.
  3. The method according to claim 1 or 2, wherein the second upstream wavelength path corresponds to at least one registration period and at least one service period, and the sending, by the OLT, a second downstream frame to the to-be-activated ONU by using the at least one downstream wavelength path comprises: sending, by the OLT, the second downstream frame to the to-be-activated ONU within duration of the registration period by using the at least one downstream wavelength path; and the method further comprises: sending, by the OLT, a third downstream frame to an activated ONU in the service period by using the at least one downstream wavelength path, wherein the third downstream frame comprises the second path identifier, and the second upstream wavelength path is used to transmit upstream service data from the activated ONU.
  4. The method according to any one of claims 1 to 3, wherein an allocation structure of a downstream frame comprises an allocation identifier field and a path identifier field.
  5. The method according to claim 4, wherein if the downstream frame is the first downstream frame, the allocation identifier field is used to carry first instruction information, the first instruction information is used to instruct the activated ONU to send the upstream service data to the OLT, and the path identifier field is used to carry the first path identifier.
  6. The method according to claim 4, wherein if the downstream frame is the second downstream frame, the allocation identifier field is used to carry second instruction information, the second instruction information is used to instruct the to-be-activated ONU to be registered at the OLT, and the path identifier field is used to carry the second path identifier.
  7. The method according to claim 4, wherein if the downstream frame is the third downstream frame, the allocation identifier field is used to carry first instruction information, the first instruction information is used to instruct the activated ONU to send the upstream service data to the OLT, and the path identifier field is used to carry the second path identifier.
  8. The method according to any one of claims 4 to 7, wherein the allocation structure of the downstream frame further comprises a start time field and a grant size field, a bit length of the allocation structure of the downstream frame is 64 bits, bit lengths of the start time field and the grant size field each are 14 bits, and a bit length of the path identifier field is 4 bits; or the bit length of the allocation structure of the downstream frame is greater than 64 bits, and the bit lengths of the start time field and the grant size field each are 16 bits.
  9. A communication method based on a passive optical network, wherein the passive optical network comprises an optical line terminal, OLT, and a plurality of optical network units, ONUs, the OLT and the ONU communicate with each other by using at least one downstream wavelength path and a plurality of upstream wavelength paths, and if the ONU is an activated ONU, the method comprises: receiving (302), by the ONU, a first downstream frame from the OLT by using the at least one downstream wavelength path, wherein the first downstream frame comprises a first path identifier used to identify a first upstream wavelength path, and the first upstream wavelength path is one of the plurality of upstream wavelength paths; determining, by the ONU, the first upstream wavelength path based on the first path identifier; and sending (303), by the ONU, upstream service data to the OLT by using the first upstream wavelength path; wherein if the ONU is a to-be-activated ONU, the method further comprises: receiving (402), by the ONU, a second downstream frame from the OLT by using the at least one downstream wavelength path, wherein the second downstream frame comprises a second path identifier used to identify a second upstream wavelength path, and the first upstream wavelength path and the second upstream wavelength path in the plurality of upstream wavelength paths do not interfere with each other; and sending (403), by the ONU, a registration request message to the OLT by using the second upstream wavelength path.
  10. The method according to claim 9, wherein that the first upstream wavelength path and the second upstream wavelength path in the plurality of upstream wavelength paths do not interfere with each other is specifically that: if the first upstream wavelength path and the second upstream wavelength path are located in a same fiber, a wavelength corresponding to the first upstream wavelength path and a wavelength corresponding to the second upstream wavelength path are different from each other; or the first upstream wavelength path and the second upstream wavelength path are located in different fibers.
  11. An optical line terminal OLT (1100), wherein the OLT comprises: a sending unit (1101), configured to send a first downstream frame to an activated optical network unit, ONU, by using at least one downstream wavelength path, wherein the OLT and the activated ONU communicate with each other by using the at least one downstream wavelength path and a plurality of upstream wavelength paths, the first downstream frame comprises a first path identifier used to identify a first upstream wavelength path, and the first upstream wavelength path is one of the plurality of upstream wavelength paths; and a receiving unit (1102), configured to receive upstream service data from the activated ONU by using the first upstream wavelength path; wherein the sending unit is further configured to send a second downstream frame to a to-be-activated ONU by using the at least one downstream wavelength path, wherein the second downstream frame comprises a second path identifier used to identify a second upstream wavelength path, and the first upstream wavelength path and the second upstream wavelength path in the plurality of upstream wavelength paths do not interfere with each other; the receiving unit is further configured to receive a registration request message from the to-be-activated ONU by using the second upstream wavelength path; and the OLT further comprises a processing unit, wherein the processing unit is configured to complete ranging and registration on the to-be-activated ONU based on the registration request message.
  12. An optical network unit ONU (1200), wherein the ONU comprises: a receiving unit (1201), configured to receive a first downstream frame from an OLT by using at least one downstream wavelength path, wherein the OLT and the ONU communicate with each other by using the at least one downstream wavelength path and a plurality of upstream wavelength paths, the ONU is an activated ONU, the first downstream frame comprises a first path identifier used to identify a first upstream wavelength path, and the first upstream wavelength path is one of the plurality of upstream wavelength paths; a processing unit (1202), configured to determine the first upstream wavelength path based on the first path identifier; and a sending unit (1203), configured to send upstream service data to the OLT by using the first upstream wavelength path; wherein if the ONU is a to-be-activated ONU, the receiving unit is further configured to receive a second downstream frame from the OLT by using the at least one downstream wavelength path, wherein the second downstream frame comprises a second path identifier used to identify a second upstream wavelength path, and the first upstream wavelength path and the second upstream wavelength path in the plurality of upstream wavelength paths do not interfere with each other; and the sending unit is further configured to send a registration request message to the OLT by using the second upstream wavelength path.
  13. A passive optical network system, comprising an optical line terminal, OLT, and a plurality of optical network units, ONUs, wherein the OLT and the ONU communicate with each other by using at least one downstream wavelength path and a plurality of upstream wavelength paths, the OLT is according to claim 11, and the ONU is according to claim 12.

Description

TECHNICAL FIELD This application relates to the field of optical communications technologies, and specifically, to a communication method based on a passive optical network, a related device, and a system. BACKGROUND A passive optical network (Passive Optical Network, PON) technology is a point-to-multipoint optical fiber access technology. Because an access network is sensitive to costs, a low-cost access technology is a main development direction. A method for increasing a rate of a PON system by using a single wavelength increases costs of an optical component. Therefore, in the conventional technology, a solution in which there are a plurality of upstream wavelength paths between an optical line terminal (optical line terminal, OLT) and an optical network unit (optical network unit, ONU) is proposed. A binding relationship between a downstream wavelength path and an upstream wavelength path is pre-stored on both an OLT side and an ONU side. When the OLT sends downstream service data to the ONU by using a downstream wavelength path, the ONU determines a corresponding upstream wavelength path based on the downstream wavelength path. The ONU may send upstream service data based on the upstream wavelength path. It may be learned that in the solution provided in the conventional technology, the upstream wavelength path and the downstream wavelength path need to be bound in advance, and the OLT cannot flexibly indicate, to the ONU, the upstream wavelength path used to send the upstream service data. EP3537628A1 relates to passive optical network system, optical line terminal and optical network unit. Based on a registration status of the ONU, when the ONU is in the registered state, the ONU sends the upstream service data to the OLT on the first upstream channel, to perform service communication with the OLT; and when the ONU is in the unregistered state, the ONU sends the registration response packet to the OLT on the second upstream channel, to complete registration with the OLT. US 2015/050024 A1 discloses embodiments for identifying a traffic-bearing entity. Specifically, the OLT may provide a transmission allocation for each traffic-bearing entity. The ONU1 may be designed to transmit registration messages on a specified registration wavelength and the ONU1 may process the transmission allocation. Based on the transmission allocation, the ONU1 may determine what wavelengths it is to receive and transmit signals at. The paper "An Evolutionary WDM Upgrade for EPONs" Michael P Mcgarry ET AL published Jauary, 1, 2005, proposes a method for providing an evolutionary upgrade to WDM in EPONs. It specifically outlines an extension to the MultiPoint Control Protocol (MPCP) defined by the IEEE 802.3ah committee to allow for the evolutionary upgrade to WDM within an EPON. It also looks at some methods for the Optical Line Terminal (OLT) to manage the bandwidth allocation in the now 2 dimensions (time and wavelength). EP 3 349 479 A1 enables a port on an ONU to independently complete registration with an OLT, so as to increase a supported bandwidth and a quantity of supported wavelength channels of the ONU when the ONU needs a relatively large bandwidth. SUMMARY This application provides a communication method based on a passive optical network, a related device, and a system. In a scenario in which the PON supports a plurality of wavelength paths, an upstream wavelength path used to send upstream service data is flexibly indicated to an ONU to improve bandwidth utilization of the PON. The invention has been defined in the independent claims. Further specific technical features have been defined in the dependent claims. A first aspect of the implementations of this application provides a communication method based on a passive optical network, where the passive optical network includes an optical line terminal (OLT) and a plurality of optical network units (ONUs), the OLT and the ONU communicate with each other by using at least one downstream wavelength path and a plurality of upstream wavelength paths, the plurality of ONUs include an activated ONU, and the method includes: The OLT sends a first downstream frame to the activated ONU by using the at least one downstream wavelength path, where the first downstream frame includes a first path identifier used to identify a first upstream wavelength path, and the first upstream wavelength path is one of the plurality of upstream wavelength paths. The OLT receives upstream service data from the activated ONU by using the first upstream wavelength path. In the method in this aspect, when the activated ONU supports a plurality of upstream wavelength paths, the OLT may send the first downstream frame to the activated ONU by using any one or more downstream wavelength paths, and the first upstream wavelength path indicated by the first downstream frame is any one of the plurality of upstream wavelength paths supported by the activated ONU. No binding relationship between an