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EP-4025007-B1 - COMMUNICATION METHOD AND COMMUNICATION APPARATUS

EP4025007B1EP 4025007 B1EP4025007 B1EP 4025007B1EP-4025007-B1

Inventors

  • GENG, Tingting
  • WU, Yedan
  • YAN, LE

Dates

Publication Date
20260513
Application Date
20190929

Claims (15)

  1. A communication method, comprising: sending (S201), by a first access network device, a first message to a terminal device, wherein the first message is used to indicate the terminal device to enter an inactive state; and sending (S202), by the first access network device, a second message to a core network device, wherein the second message carries context information and a first security verification parameter of the terminal device, and the first security verification parameter is used to perform security verification on the terminal device; and after sending the first message and the second message, the method further comprises: receiving (S205), by the first access network device, a third message from a second access network device, wherein the third message is used to request the context information of the terminal device; and sending (S207), by the first access network device, a fourth message to the second access network device, wherein the fourth message is used to indicate the first access network device determines not to provide the second access network device with the context information.
  2. The communication method according to claim 1, wherein the fourth message is further used to indicate identification information of the core network device.
  3. The communication method according to claim 1 or 2, wherein the first access network device stores the context information of the terminal device, and the communication method further comprises: performing, by the first access network device, security verification on the terminal device based on the first security verification parameter; and the sending, by the first access network device, a fourth message to the second access network device based on the third message comprises: when the security verification succeeds, if the first access network device determines not to provide the second access network device with the context information, sending, by the first access network device, the fourth message to the second access network device.
  4. The communication method according to any one of claims 1 to 3, wherein the third message carries a second security verification parameter of the terminal device, the second security verification parameter is used to perform security verification on the terminal device, and the communication method further comprises: sending, by the first access network device, a fifth message to the core network device, wherein the fifth message carries the second security verification parameter, to update a security verification parameter stored in the core network device.
  5. The communication method according to any one of claims 1 to 4, wherein after the sending, by the first access network device, a second message to a core network device, the communication method further comprises: deleting, by the first access network device, the context information of the terminal device.
  6. The communication method according to claim 1, further comprising: receiving, by the core network device, the second message from the first access network device; and storing, by the core network device, the context information and the first security verification parameter.
  7. The communication method according to claim 6, wherein the communication method further comprises: receiving, by the core network device, a sixth message from the second access network device, wherein the sixth message is used to request the context information of the terminal device; performing, by the core network device, security verification on the terminal device based on the first security verification parameter; and when the security verification succeeds, sending, by the core network device, a seventh message to the second access network device, wherein the seventh message carries the context information, or the seventh message is used to indicate the core network device determines not to provide the second access network device with the context information.
  8. The communication method according to claim 7, wherein the sixth message carries a second security verification parameter of the terminal device, the second security verification parameter is used to perform security verification on the terminal device, and the communication method further comprises: updating, by the core network device, a security verification parameter from the first security verification parameter to the second security verification parameter.
  9. The communication method according to claim 1, further comprising: receiving, by the second access network device, an eighth message from the terminal device, wherein the eighth message is used to request to resume a connection; sending, by the second access network device, a sixth message to a core network device, wherein the sixth message is used to request the context information of the terminal device; and receiving, by the second access network device, a seventh message from the core network device, wherein the seventh message carries the context information, or the seventh message is used to indicate the core network device determines not to provide the second access network device with the context information.
  10. The communication method according to claim 9, wherein before the sending, by the second access network device, a sixth message to a core network device, the communication method further comprises: sending, by the second access network device, the third message to the first access network device based on the eighth message; and receiving, by the second access network device, the fourth message from the first access network device, wherein the fourth message is further used to indicate identification information of the core network device; and the sending, by the second access network device, a sixth message to the core network device comprises: sending, by the second access network device, the sixth message to the core network device based on the identification information of the core network device.
  11. The communication method according to claim 9 or 10, wherein the sixth message carries a second security verification parameter of the terminal device, to enable the core network device to update a security verification parameter from a first security verification parameter to the second security verification parameter, and the second security verification parameter is used to perform security verification on the terminal device.
  12. A communication system comprising a first access network device, comprising units for performing the corresponding steps according to any one of claims 1 to 11.
  13. The communication system according to claim 12 further comprising a core network device, comprising units for performing the corresponding steps according to any one of claims 1 to 11.
  14. The communication system further comprising a second access network device, comprising units for performing the corresponding steps according to any one of claims 1 to 11.
  15. A computer program product, wherein the computer program product comprises a first set of instructions, which when run by a first access network device causes the first access network device to perform the corresponding steps according to any one of claims 1 to 11.

Description

TECHNICAL FIELD This application relates to the communication field, and in particular, to a communication method and a communication apparatus in the communication field. BACKGROUND A radio resource control (radio resource control, RRC) status of a terminal device includes a connected state (RRC_CONNECTED), an inactive state (RRC_INACTIVE), and an idle state (RRC_IDLE). When a terminal device is in the connected state, the terminal device has established links with an access network device and a core network device. When data arrives at a network, the core network device and the access network device may directly transmit the data to the terminal device. When a terminal device is in the inactive state, it indicates that the terminal device has previously established links with an access network device and a core network device, but the link between the terminal device and the access network device is released. Although the link is released, the access network device needs to store a context of the terminal device. When data needs to be transmitted, the access network device may quickly resume the released link based on the context of the terminal device. When a terminal device is in the idle state, there is no link between the terminal device and an access network device or between the terminal device and a core network device. When data needs to be transmitted, a link between the terminal device and the access network device and a link between the terminal device and the core network device need to be established. It can be learned from the foregoing that, the inactive state can change by using an RRC connection release message only when a terminal device is in the connected state. When the terminal device is released from the connected state to the inactive state, an access network device (which may be referred to as an anchor access network device or a source access network device) that serves the terminal device stores a context of the terminal device, and allocates an identifier to the terminal device, to identify the stored context of the terminal device. When subsequently initiating an RRC connection resume procedure, the terminal device needs to carry the identifier and send the identifier to an access network device (which may be referred to as a target access network device) that currently serves the terminal device, to obtain the context of the terminal device. Because the terminal device has mobility, the target access network device and the anchor access network device are usually different devices, and the target access network device needs to obtain the context of the terminal device from the anchor access network device based on the identifier. It is considered that in some scenarios (for example, a non-terrestrial network (non-terrestrial network, NTN)), a movement speed of the access network device is fast. For example, the terminal device needs to change a serving cell (in other words, change the target access network device) every 1 minute to 2 minutes. However, the context of the terminal device is stored only in the anchor access network device. If the terminal device in the inactive state requests to resume an RRC connection, it is difficult for the target access network device to find the anchor access network device to obtain the context information of the terminal device from the anchor access network device. Therefore, how to ensure running of a connection resume mechanism of the terminal device becomes an urgent problem to be resolved. WO2018121218A1 relates to service request processing method and associated apparatus. WO2019158026A1 relates to communication method and apparatus. SUMMARY This application provides a communication method and a communication system, to ensure running of a connection resume mechanism of a terminal device, and reduce impact of mobility of an access network device on a connection resume procedure of the terminal device, thereby improving system performance. The invention has been defined in the independent claims. Further specific technical features have been defined in the dependent claims. According to a first aspect, a communication method is provided, and includes: A first access network device sends a first message to a terminal device, where the first message is used to indicate the terminal device to enter an inactive state. The first access network device sends a second message to a core network device, where the second message carries context information and a first security verification parameter of the terminal device, and the first security verification parameter is used to perform security verification on the terminal device. After sending the first message and the second message, the method further includes the following. The first access network device receives a third message from a second access network device, where the third message is used to request the context information of the terminal device. The first access network device s