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US-12628049-B2 - Method for coordination of control plane traffic management during device reconfigurations and related apparatus

US12628049B2US 12628049 B2US12628049 B2US 12628049B2US-12628049-B2

Abstract

The present disclosure relates generally to communications, and more particularly to communication methods and related devices and nodes for control plane traffic management. Among other things, the disclosure presents a method performed by a central unit (CU) of a network node for coordination of control plane traffic management during a communication device reconfiguration in a telecommunications network. The method may, e.g., comprise receiving information from a distributed unit (DU) of the network node alerting the CU to reset a packet data convergence protocol (PDCP) sequence number of control plane traffic signaled from the communication device as a consequence of an event in the telecommunications network; and responsive to receiving the information, resetting the PDCP sequence number of the control plane traffic signaled from the communication device.

Inventors

  • Angelo Centonza
  • Thomas Walldeen
  • Fredrik Hultin
  • Ioanna Pappa

Assignees

  • TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

Dates

Publication Date
20260512
Application Date
20201028

Claims (20)

  1. 1 . A method performed by a central unit (“CU”) of a source network node for coordination of control plane traffic management during a communication device reconfiguration in a telecommunications network, the method comprising: receiving information from a distributed unit (“DU”) of the source network node alerting the CU to reset a packet data convergence protocol (“PDCP”) sequence number of control plane traffic signaled from the communication device as a consequence of an event in the telecommunications network; and responsive to receiving the information, resetting the PDCP sequence number of the control plane traffic signaled from the communication device, wherein receiving the information comprises receiving from the DU an uplink message from a target cell and an indicator that the uplink message is a first message sent from the target cell.
  2. 2 . The method of claim 1 , wherein the uplink message comprises a radio resource control (“RRC”) message from the target cell.
  3. 3 . The method of claim 1 , wherein the indicator comprises a flag indicating that the uplink message is the first message sent from the target cell.
  4. 4 . The method of claim 3 , wherein the flag comprises a re-established signaling radio bearer (“SRB”) flag indicating that the RRC message is the first message on a re-established SRB flow.
  5. 5 . The method of claim 1 , wherein the uplink message is received from the DU over an F1 interface.
  6. 6 . The method of claim 1 , wherein the uplink message comprises an uplink RRC message transfer message.
  7. 7 . The method of claim 1 , further comprising: receiving from the DU an other message comprising an indication that the DU supports sending one or more messages that include the indicator; and responsive to receiving the other message, waiting to reset the PDCP sequence number of the control plane traffic signaled from the UE until the CU receives the uplink message including the indicator.
  8. 8 . A source network node in a telecommunications network, the source network node configured to provide a central unit (“CU”), the source network node comprising: processing circuitry; and memory coupled to the processing circuitry and having instructions stored therein that are executable by the processing circuitry to cause the CU to perform operations comprising: receiving information from a distributed unit (“DU”) of the source network node alerting the CU to reset a packet data convergence protocol (“PDCP”) sequence number of control plane traffic signaled from the communication device as a consequence of an event in the telecommunications network; and responsive to receiving the information, resetting the PDCP sequence number of the control plane traffic signaled from the communication device, wherein receiving the information comprises receiving from the DU an uplink message from a target cell and an indicator that the uplink message is a first message sent from the target cell.
  9. 9 . The source network node of claim 8 , wherein the uplink message comprises a radio resource control (“RRC”) message from the target cell.
  10. 10 . The source network node of claim 8 , wherein the indicator comprises a flag indicating that the uplink message is the first message sent from the target cell.
  11. 11 . The source network node of claim 10 , wherein the flag comprises a re-established signaling radio bearer (“SRB”) flag indicating that the RRC message is the first message on a re-established SRB flow.
  12. 12 . A method performed by a distributed unit (“DU”) of a source network node for coordination of control plane traffic management during a communication device reconfiguration in a telecommunications network, the method comprising: signaling a message to a central unit (“CU”) of the source network node comprising an indicator of timing of a packet data convergence protocol (“PDCP”) sequence number for control plane traffic signaled from the communication device for an event in the telecommunications network, wherein signaling the message to the CU comprises signaling an uplink message from a target cell and the indicator that the uplink message is a first message sent from the target cell.
  13. 13 . The method of claim 12 , wherein the uplink message comprises a radio resource control (“RRC”) message from the target cell.
  14. 14 . The method of claim 12 , wherein the indicator comprises a flag indicating that the uplink message is the first message sent from the target cell.
  15. 15 . The method of claim 14 , wherein the flag comprises a re-established signaling radio bearer (“SRB”) flag indicating that the RRC message is the first message on a re-established SRB flow.
  16. 16 . The method of claim 12 , wherein the message is signaled by the DU to the CU over an F1 interface.
  17. 17 . The method of claim 12 , wherein the message comprises an uplink RRC message transfer message.
  18. 18 . A source network node of a telecommunications network, the source network node configured to provide a distributed unit (“DU”), the source network node comprising: processing circuitry; and memory coupled to the processing circuitry and having instructions stored therein that are executable by the processing circuitry to cause the DU to perform operations comprising: signaling a message to a central unit (“CU”) of the source network node comprising an indicator of timing of a packet data convergence protocol (“PDCP”) sequence number for control plane traffic signaled from the communication device for an event in the telecommunications network, wherein signaling the message to the CU comprises signaling an uplink message from a target cell and the indicator that the uplink message is a first message sent from the target cell.
  19. 19 . The source network node of claim 18 , wherein the indicator comprises a flag indicating that the uplink message is the first message sent from the target cell.
  20. 20 . The DU source network node of claim 19 , wherein the flag comprises a re-established signaling radio bearer (“SRB”) flag indicating that the RRC message is the first message on a re-established RB flow.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a 35 U.S.C. § 371 national stage application of PCT International Application No. PCT/SE2020/051042 filed on Oct. 28, 2020, which claims the benefit of U.S. Provisional Patent Application Ser. No. 62/933,335, filed on Nov. 8, 2019, the disclosures and content of which are incorporated by reference herein in their entireties. TECHNICAL FIELD The present disclosure relates generally to communications, and more particularly to communication methods and related devices and nodes for control plane traffic management. BACKGROUND The current 5G Radio Access Network (RAN) is described in 3GPP Technical Specification (TS) 38.401 v15.6.0. FIG. 1 illustrates the overall architecture of current 5G Radio Access Network (RAN) architecture described in TS38.401 v15.6.0 as follows: The NG-RAN includes a set of g NodeBs (gNBs) connected to the 5G Core Network (5GC) through the NG. A gNB can support Frequency Division Duplex (FDD) mode, Time Division Duplex (TDD) mode or dual mode operation.gNBs can be interconnected through the Xn.A gNB may include a gNB-Central Unit (CU) and gNB-Distributed Units (DUs).A gNB-CU and a gNB-DU are connected via F1 logical interface.One gNB-DU is connected to only one gNB-CU. NG, Xn and F1 are logical interfaces. For NG-RAN, the NG and Xn-C interfaces for a gNB including a gNB-CU and gNB-DUs, terminate in the gNB-CU. For EN-DC, the S1-U and X2-C interfaces for a gNB including of a gNB-CU and gNB-DUs, terminate in the gNB-CU. The gNB-CU and connected gNB-DUs are only visible to other gNBs and the 5GC as a gNB. The NG-RAN is layered into a Radio Network Layer (RNL) and a Transport Network Layer (TNL). The NG-RAN architecture, described above (the NG-RAN logical nodes and interfaces between them) is defined as part of the RNL. For each NG-RAN interface (NG, Xn, F1), the related TNL protocol and the functionality are specified. The TNL provides services for user plane transport and signaling transport. In NG-Flex configuration, each gNB is connected to all access management function (AMF) nodes within an AMF Region. The AMF Region is defined in 3GPP TS 23.501. In a split gNB architecture the event of a handover is managed by F1AP procedures that: modify the User Equipment (UE) context, support signaling of radio resource control (RRC) messages to and from the UE to allow opportune UE reconfigurations aimed at letting the UE properly handover to the target cell, such as the F1: UE Context Modification Procedure; and/or purely allow the transfer of RRC messages between gNB-CU-control plane (CP) and gNB-DU, such as the RRC Message Transfer procedures. SUMMARY It is in view of the above considerations and others that the various embodiments of the present invention have been made. It is therefore a general object of embodiments described herein to allow for an improved coordination of control plane traffic management during a communication device reconfiguration in a telecommunications network. This general object has been addressed by the appended independent claims. Advantageous embodiments have been described in the appended dependent claims. In a first of its aspects, the present disclosure presents a method performed by a central unit (CU) of a network node for coordination of control plane traffic management during a communication device reconfiguration in a telecommunications network. The method comprises: receiving information from a distributed unit (DU) of the network node alerting the CU to reset a packet data convergence protocol (PDCP) sequence number of control plane traffic signaled from the communication device as a consequence of an event in the telecommunications network; and responsive to receiving the information, resetting the PDCP sequence number of the control plane traffic signaled from the communication device. In some embodiments, the information from the DU of the network node alerting the CU to reset a PDCP sequence number of control plane traffic signaled from the communication device comprises receiving from the DU a first message comprising an uplink message from a target cell and an indicator that the uplink message is the first message sent from the target cell. In some embodiments, the uplink message comprises a radio resource control (RRC) message from the target cell. In some embodiments, the indicator comprises a flag indicating that the RRC message is a first message sent from the target cell. In some embodiments, the flag comprises a re-established signaling radio bearer (SRB) flag indicating that the RRC message is the first message on a re-established SRB flow. In some embodiments, wherein the first message is received from the DU over an F1 interface. In some embodiments, the first message comprises an uplink RRC message transfer message. In some embodiments, the method further comprises: receiving from the DU a second message comprising an indication that the DU supports sending a message that includ