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US-20260129534-A1 - COMMUNICATION METHOD AND RELATED DEVICE

US20260129534A1US 20260129534 A1US20260129534 A1US 20260129534A1US-20260129534-A1

Abstract

Embodiments of this application provide a communication method and a related device. According to the communication method, once a UE cannot establish, in a call, an RRC connection with a network device corresponding to a cell currently being camped on, the UE may lower a priority of the cell that the UE is currently camped on, so that the UE may choose another cell other than a problem cell to camp on through cell reselection subsequently, thereby avoiding problems of call drops and silent calls caused by camping on the problem cell for a long time.

Inventors

  • Haibo Li

Assignees

  • HONOR DEVICE CO., LTD.

Dates

Publication Date
20260507
Application Date
20260105
Priority Date
20230712

Claims (20)

  1. 1 . A communication method, applied to a terminal device, the method comprising: camping, by the terminal device, on a first cell; performing, by the terminal device, a call in the first cell; performing, by the terminal device, cell selection when a first network abnormality occurs during the call in the first cell, and choosing to camp on the first cell; starting, by the terminal device, a T 301 timer, and sending a first message to a first network device, wherein the first network device is a network device corresponding to the first cell, and the first message is used to request random access; lowering, by the terminal device, a carrier frequency priority of the first cell when the T 301 timer times out; performing, by the terminal device, cell reselection based on the lowered carrier frequency priority of the first cell, and choosing to camp on a second cell, wherein the second cell is different from the first cell; establishing, by the terminal device, an RRC connection with a second network device, wherein the second network device is a network device corresponding to the second cell; and still performing, by the terminal device, the call on the second cell through the established RRC connection.
  2. 2 . The method according to claim 1 , wherein after the terminal device lowers the carrier frequency priority of the first cell, the performing, by the terminal device, cell reselection specifically comprises: sending, by an RRC layer in the terminal device, a second message to an ML 1 layer in the terminal device, wherein the second message is used to instruct the ML 1 layer to perform accelerated cell reselection; receiving, by the ML 1 layer in the terminal device, the second message; and performing, by the terminal device, the accelerated cell reselection based on the second message; wherein the performing the accelerated cell reselection comprises: a duration for which the terminal device camps on an original cell before performing the cell reselection is less than a first preset duration.
  3. 3 . The method according to claim 2 , wherein the performing the accelerated cell reselection further comprises: a duration for which the terminal device evaluates a target cell during the cell reselection is less than a second preset duration, and the target cell comprises the second cell.
  4. 4 . The method according to claim 3 , wherein a sum of a duration for which the terminal device camps on an original cell and the duration for evaluating the target cell is less than a duration of a T 3411 timer currently used by the terminal device.
  5. 5 . The method according to claim 1 , wherein that the first network abnormality occurs during the call performed by the terminal device in the first cell specifically comprises: during the call performed by the terminal device when camping on the first cell, a failure in reading a system message of the first cell causes a radio link failure (RLF).
  6. 6 . The method according to claim 1 , wherein the first cell is one of at least one neighboring cell of a third cell, and before the performing cell selection, the method further comprises: camping, by the terminal device, on the third cell to perform the call; and performing, by the terminal device, handover on the third cell to camp on the first cell; and the first network abnormality occurs when the terminal device camps on the first cell to perform the call.
  7. 7 . The method according to claim 6 , wherein after the performing, by the terminal device, handover on the third cell to camp on the first cell, the method further comprises: initiating, by the terminal device, a TAU process; after the terminal device sends the first message to the first network device, the method further comprises: starting, by the terminal device, a T 3411 timer after the T 301 timer times out; and the establishing, by a terminal device, an RRC connection with a second network device specifically comprises: re-initiating, by the terminal device, a TAU process when the T 3411 timer times out, and establishing the RRC connection with the second network device.
  8. 8 . The method according to claim 7 , wherein in neighboring cells of the third cell, the first cell has strongest signal strength, and the first cell has a highest carrier frequency priority.
  9. 9 . The method according to claim 7 , wherein the lowered carrier frequency priority corresponding to the first cell is equal to a minimum value of priorities corresponding to several neighboring cells of the third cell.
  10. 10 . A communication method, applied to a terminal device, the method comprising: performing cell reselection when a second network abnormality occurs during a call performed by the terminal device when camping on a first cell, and choosing to camp on the first cell; starting, by the terminal device, a T 300 timer, and sending a first message to a first network device, wherein the first network device is a network device corresponding to the first cell, and the first message is used to request random access; lowering, by the terminal device, a carrier frequency priority of the first cell when the T 300 timer times out; performing, by the terminal device, cell reselection based on the lowered carrier frequency priority of the first cell, and choosing to camp on a second cell, wherein the second cell is different from the first cell; establishing, by the terminal device, an RRC connection with a second network device, wherein the second network device is a network device corresponding to the second cell; and still performing, by the terminal device, the call on the second cell through the established RRC connection.
  11. 11 . The method according to claim 10 , wherein after the terminal device lowers the carrier frequency priority of the first cell, the performing, by the terminal device, cell reselection specifically comprises: sending, by an RRC layer in the terminal device, a second message to an ML 1 layer in the terminal device, wherein the second message is used to instruct the ML 1 layer to perform accelerated cell reselection; receiving, by the ML 1 layer in the terminal device, the second message; and performing, by the terminal device, the accelerated cell reselection based on the second message; wherein the performing the accelerated cell reselection comprises: a duration for which the terminal device camps on an original cell before performing the cell reselection is less than a first preset duration.
  12. 12 . The method according to claim 11 , wherein the performing the accelerated cell reselection further comprises: a duration for which the terminal device evaluates a target cell during the cell reselection is less than a second preset duration, and the target cell comprises the second cell.
  13. 13 . The method according to claim 12 , wherein a sum of a duration for which the terminal device camps on an original cell and the duration for evaluating the target cell is less than a duration of a T 3411 timer currently used by the terminal device.
  14. 14 . The method according to claim 10 , wherein that the second network abnormality occurs during a call performed by the terminal device when camping on the first cell specifically comprises: during the call performed by the terminal device when camping on the first cell, the RRC layer in the terminal device notifies a NAS layer that a lower layer failure has occurred, and determines, based on the notification, that a TAU fails.
  15. 15 . The method according to claim 14 , wherein the first cell is one of at least one neighboring cell of a third cell, and before the performing cell reselection, and choosing to camp on the first cell, the method further comprises: camping, by the terminal device, on the third cell to perform the call; and performing, by the terminal device, handover on the third cell to camp on the first cell; and performing cell selection when a first network abnormality occurs during a call performed by the terminal device when camping on the first cell, and choosing to camp on the second cell; starting, by the terminal device, a T 301 timer, and sending the first message to the first network device; and notifying, by the RRC layer in the terminal device, the NAS layer that the lower layer failure occurs when the T 301 timer times out.
  16. 16 . The method according to claim 15 , wherein after the performing, by the terminal device, handover on the third cell to camp on the first cell, the method further comprises: initiating, by the terminal device, a TAU process; after the starting, by the terminal device, a T 301 timer, and sending the first message to the first network device, the method further comprises: starting, by the terminal device, a T 3411 timer when the T 301 timer times out; and the starting, by the terminal device, a T 300 timer specifically comprises: re-initiating, by the terminal device, a TAU process when the T 3411 timer times out, and starting the T 300 timer.
  17. 17 . The method according to claim 10 , wherein after the starting, by the terminal device, a T 300 timer, and sending the first message to the first network device, the method further comprises: starting, by the terminal device, a T 3411 timer when the T 300 timer times out; and the establishing, by a terminal device, an RRC connection with a second network device specifically comprises: re-initiating, by the terminal device, a TAU process when the T 3411 timer times out, and establishing the RRC connection with the second network device.
  18. 18 . The method according to claim 15 , wherein in neighboring cells of the third cell, the first cell has strongest signal strength, and the first cell has a highest carrier frequency priority.
  19. 19 . The method according to claim 15 , wherein the lowered carrier frequency priority corresponding to the first cell is equal to a minimum value of priorities corresponding to several neighboring cells of the third cell.
  20. 20 . A terminal device, comprising a processor and a memory, wherein the processor is configured to invoke and execute a computer program stored in the memory, so that the terminal device implements the method comprises: camping, by the terminal device, on a first cell; performing, by the terminal device, a call in the first cell; performing, by the terminal device, cell selection when a first network abnormality occurs during the call in the first cell, and choosing to camp on the first cell; starting, by the terminal device, a T 301 timer, and sending a first message to a first network device, wherein the first network device is a network device corresponding to the first cell, and the first message is used to request random access; lowering, by the terminal device, a carrier frequency priority of the first cell when the T 301 timer times out; performing, by the terminal device, cell reselection based on the lowered carrier frequency priority of the first cell, and choosing to camp on a second cell, wherein the second cell is different from the first cell; establishing, by the terminal device, an RRC connection with a second network device, wherein the second network device is a network device corresponding to the second cell; and still performing, by the terminal device, the call on the second cell through the established RRC connection.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of International Application No. PCT/CN2024/082660, filed on March 20, 2024, which claims priority to Chinese Patent Application No. 202310859458.1, filed on July 12, 2023, both of which are incorporated herein by reference in their entireties. TECHNICAL FIELD This application relates to the field of communication technologies, and in particular, to a communication method and a related device. BACKGROUND When a user equipment (UE) is in a call state, the UE originally camps on a cell A. Based on cell selection/cell reselection/cell handover, the UE may change from originally camping on a cell A to camping on a cell B. However, when the cell B is a problem cell, problems such as a Radio Link Failure (RLF) may occur, and the UE performs cell selection. Because the UE originally camps on the cell B, and the cell B has strongest signal strength, the UE still chooses to camp on the cell B. In this case, the UE triggers a radio resource control RRC) connection reestablishment process. Once the RRC connection establishment fails, the UE enters an idle state (namely, an idle state). In this case, the UE performs cell reselection. Because a combination of the signal strength and the priority of the cell B is better than that of another cell, the UE still chooses the cell B and initiates an RRC connection establishment process. Once the RRC connection establishment fails again, the UE enters the idle state again. In this case, the UE performs cell reselection again. Same as the foregoing reason, because the combination of the signal strength and the priority of the cell B is better than that of another cell, the UE still chooses the cell B and initiates the RRC connection establishment process. It may be understood that because the combination of the signal strength and the priority of the cell B is better than that of another cell, the UE most probably always chooses the cell B when performing cell reselection. However, because the cell B is a problem cell, the UE cannot successfully establish the RRC connection with the cell B. This means that a process in which the UE chooses the cell B and the RRC connection cannot be successfully established between the UE and the cell B is cyclically performed. Once the number of times of circulation is excessively large, problems that a call of the UE ends (namely, a call is dropped) and that a call is silent for a long time may be caused. For example, once a time spent by the UE in choosing a cell B and finally successfully establishing the RRC connection with the cell B exceeds a specific threshold (for example, 20 seconds), the UE actively sends a BYE message to the cell B after the UE successfully establishes the RRC connection with the cell B, so that the call of the UE ends. In addition, because the UE is in the call state, the call of the UE cannot be continued if the UE does not successfully establish the RRC connection with the cell B. In other words, the UE may have a problem of silent calls. Therefore, how to avoid the call drops of the UE and the silent calls in a call scenario is problem to be urgently resolved currently. SUMMARY Embodiments of this application provide a communication method and a related device, to avoid call drops of a UE in a call scenario, and/or avoid or optimize problem of silent calls (for example, reducing a silence time of a call) for a long time. According to a first aspect, this application provides a communication method. The method may apply to a terminal device. The method may include: The terminal device camps on a first cell. The terminal device performs a call in the first cell. The terminal device performs cell selection in a case in which a first network abnormality occurs during a call performed by the terminal device when camping on a first cell, and chooses to camp on the first cell. The terminal device starts a T301 timer, and sends a first message to a first network device, where the first network device is a network device corresponding to the first cell, and the first message is used to request random access. The terminal device lowers a carrier frequency priority of the first cell when the T301 timer times out. The terminal device performs cell reselection based on the lowered carrier frequency priority of the first cell, and chooses to camp on a second cell, where the second cell is different from the first cell. The terminal device establishes an RRC connection with a second network device, where the second network device is a network device corresponding to the second cell. The terminal device still performs the call on the second cell through the established RRC connection. In the solution provided in this application, when the first network abnormality occurs during the call performed by the terminal device, the terminal device may perform cell selection. Because a cell originally camped on has strongest signal strength, the terminal device s