WO-2026092374-A1 - COMMUNICATION METHOD AND APPARATUS

Abstract

A communication method and apparatus, relating to the technical field of wireless communications. The method comprises: a terminal device receives first indication information, wherein the first indication information indicates that the terminal device changes from a radio resource control (RRC) connected state to a first state; and entering the first state on the basis of the first indication information, wherein context information stored by the terminal device in the first state includes part of context information among context information stored by the terminal device in the RRC connected state, and the part of context information includes security configuration information.

Inventors

• LI, Chenwan
• LI, Ruijie

Assignees

• 华为技术有限公司

Dates

Publication Date

20260507

Application Date

20251027

Priority Date

20241101

Claims (20)

1. A communication method, characterized in that it is applied to a terminal device and includes: Receive a first indication information, the first indication information instructing the terminal device to change from the Radio Resource Control (RRC) connected state to a first state; Entering the first state according to the first instruction information, in the first state, the context information saved by the terminal device in the first state includes part of the context information saved by the terminal device in the RRC connection state, and the part of the context information includes security configuration information.
2. The method as described in claim 1, characterized in that, in the first state, the terminal device stops measuring the periodic reference signal; or In the first state, the terminal device measures the periodic reference signal, and the length of the measurement period is greater than the length of the measurement period when measuring the periodic reference signal in the RRC connected state or the RRC inactive state; or In the first state, the terminal device measures the periodic reference signal, and the length of the measurement period is equal to the length of the measurement period when measuring the periodic reference signal in the RRC connected state or the RRC inactive state.
3. The method as described in any one of claims 1-2, characterized in that, after receiving the first indication information, it further includes: Release or suspend one or more of the following context information of the terminal device in RRC connection state: air interface context information related to data transmission, periodic measurement configuration information.
4. The method according to any one of claims 1-3, characterized in that, before receiving the first indication information, it further includes: Send a first request, which is used to request entry into the first state.
5. The method as described in claim 4, wherein sending the first request comprises: Based on the quality and/or service information of the serving cell, determine the change from RRC connected state to the first state, and send the first request; or Based on measurements of the downlink signal, a change from RRC connected state to the first state is determined, and the first request is sent; or Based on the measurement of the downlink signal and the statistics of the transmitted data volume, it is determined that the connection state has changed from the RRC connection state to the first state, and the first request is sent.
6. The method according to any one of claims 1-5, wherein the terminal device, in the first state, further includes: Receive a second indication information, the second indication information being used to instruct the terminal device to change from the first state to the RRC connection state; Upon entering the RRC connection state according to the second instruction information, the terminal device restores the context information of the RRC connection state and resumes the measurement of the reference signal for the period under the RRC connection.
7. The method according to any one of claims 1-5, wherein when the terminal device is in the first state, it further includes: Receive a third indication message, the third indication message being used to instruct the terminal device to change from the first state to the RRC inactive state; Enter the RRC inactive state according to the third instruction information.
8. The method as described in claim 7, wherein when the terminal device is in the RRC inactive state, it further includes: Receive a fourth indication message, the fourth indication message being used to instruct the terminal device to change from the RRC inactive state to the first state; Enter the first state according to the fourth instruction information.
9. The method as described in any one of claims 1-8 is characterized in that the first state includes a first mode and/or a second mode, wherein the terminal device performs data transmission in the first mode and does not perform data transmission in the second mode.
10. The method as described in claim 9, characterized in that, when the terminal device is in the first mode, it further includes: performing data transmission; receiving fifth indication information, and changing from the first mode to the second mode according to the fifth indication information, wherein the fifth indication information is used to indicate that the terminal device has changed from the first mode to the second mode, or to indicate that data transmission is complete; or When the terminal device is in the second mode, it further includes: receiving sixth instruction information; and changing from the second mode to the first mode according to the sixth instruction information.
11. The method as described in claim 9, characterized in that it further comprises: Upon receiving signaling for data transmission scheduling, a timer is started, and during the operation of the timer, the terminal device is in the first mode; When the timer expires, the system switches from the first mode to the second mode.
12. The method according to any one of claims 1-11, wherein when the terminal device is in the first state, it further includes: When switching or changing from a source cell to a target cell, the source cell and the target cell belong to the same area; An access request or update indication is sent to the target cell. The access request and the update indication are used to trigger the target cell to send a UE change cell indication to the source cell. The UE change cell indication is used to trigger the source cell to send the saved context information of the terminal device to the target cell.
13. A communication method, characterized in that it is applied to a network device and includes: Send a first indication message, the first indication message instructing the terminal device to change from the Radio Resource Control (RRC) connected state to a first state; in the first state, the terminal device stops measuring the periodic reference signal, and the context information stored by the terminal device in the first state includes a portion of the context information stored by the terminal device in the RRC connected state, the portion of the context information including security configuration information; Release or suspend a portion of the context information of the terminal device in the RRC connection state stored by the network device.
14. The method as described in claim 13, wherein, in the first state, the terminal device stops measuring the periodic reference signal; or In the first state, the terminal device measures the periodic reference signal, and the length of the measurement period is greater than the length of the measurement period when measuring the periodic reference signal in the RRC connected state or the RRC inactive state; or In the first state, the terminal device measures the periodic reference signal, and the length of the measurement period is equal to the length of the measurement period when measuring the periodic reference signal in the RRC connected state or the RRC inactive state.
15. The method as described in any one of claims 13-14, characterized in that, releasing or suspending a portion of the context information of the terminal device in the RRC connection state stored by the network device includes: Release or suspend one or more of the following context information of the terminal device in RRC connection state stored by the network device: air interface context information related to data transmission, periodic measurement configuration information.
16. The method as described in any one of claims 13-15, characterized in that, before sending the first indication information, it further includes: Receive a first request, which is used to request to enter the first state; The sending of the first indication information includes: Send the first instruction information according to the first request.
17. The method according to any one of claims 13-16, wherein the terminal device, in the first state, further includes: Send a second indication message, the second indication message being used to instruct the terminal device to change from the first state to the RRC connection state; Restore the context information of the terminal device in the RRC connection state saved by the network device.
18. The method according to any one of claims 13-16, wherein when the terminal device is in the first state, it further includes: Send a third indication message, which is used to instruct the terminal device to change from the first state to the RRC inactive state.
19. The method as described in claim 18, wherein when the terminal device is in the RRC inactive state, it further includes: Send a fourth indication message, which is used to instruct the terminal device to change from the RRC inactive state to the first state.
20. The method as described in any one of claims 13-19 is characterized in that the first state includes a first mode and/or a second mode, wherein the terminal device performs data transmission in the first mode and does not perform data transmission in the second mode.

Description

A communication method and apparatus Cross-reference of related applications This application claims priority to Chinese Patent Application No. 202411562437.4, filed on November 1, 2024, entitled "A Communication Method and Apparatus", the entire contents of which are incorporated herein by reference. Technical Field This application relates to the field of wireless communication technology, and in particular to a communication method and apparatus. Background Technology In Long Term Evolution (LTE) systems, the Radio Resource Control (RRC) state of a terminal device includes RRC Connected State and RRC Idle State. In RRC Connected State, there is a signaling connection between the terminal device and the base station, allowing data transmission between them; alternatively, there may be no data transmission but only RRC signaling. In RRC Idle State, there is no signaling connection between the terminal device and the base station, and there is neither data transmission nor RRC signaling. When a terminal device is in RRC Idle State, the core network can page the terminal device within the area corresponding to its Tracking Area Identity (TAI) list, using one or more base stations within that area. When a terminal device moves out of the area corresponding to the TAI list, a core network registration process can be initiated to perform a non-access stratum (NAS) registration update. The core network registers the location of the terminal device and updates the terminal device registration area, that is, it reassigns a TAI list containing the tracking area (TA) of the cell to which the terminal device is currently located to the terminal device. In 5G systems, an RRC inactive state is introduced in addition to the RRC connected and RRC idle states. In the RRC connected state, an RRC connection is established between the terminal device and the base station, and both the terminal device and the base station maintain the terminal device's context information. In the RRC idle state, no RRC connection exists between the terminal device and the base station, and neither the terminal device nor the base station needs to maintain the terminal device's context information. In the RRC inactive state, the terminal device suspends data processing, but the terminal device and the base station still maintain some of the terminal device's context information, allowing the terminal device to quickly return to the RRC connected state. Because RRC inactive terminal devices suspend data processing, they can maintain a power consumption level similar to that of the RRC idle state. Meanwhile, since the base station still maintains the context information of the terminal devices in the RRC inactive state, the terminal devices remain in the connection management connected (CM-connected) state. This means that the terminal devices still have a signaling connection with the access and mobility management function (AMF). Therefore, when there is a data transmission requirement to migrate the terminal device from the RRC inactive state to the RRC connected state, compared to migrating from the RRC idle state to the RRC connected state, there is no need to carry out establishment and authentication processes, thus allowing for a faster resumption of the terminal device's services. Regarding data transmission, in RRC connected mode, when data transmission is needed, the terminal device can immediately perform data transmission based on the RRC connection, achieving a rapid transition from non-connected transmission to data transmission. In RRC inactive mode, for downlink data transmission, the terminal device needs to receive a paging message during paging and access the network based on the paging message before it can receive data. For uplink transmission, the terminal device needs to restore the RRC connection based on the saved context information before it can send data. Compared to RRC connected mode, the transition time from non-connected transmission to data transmission is slower. In RRC idle mode, since the terminal device does not save context information, it takes longer to establish an RRC connection with the network side compared to restoring the RRC connection with the network side in RRC inactive mode. Therefore, the transition time from non-connected transmission to data transmission is even slower. Regarding energy saving, in RRC connected mode, the terminal device needs to perform channel measurements on periodic reference signals, such as measuring the channel state information reference signal (CSI-RS) with a period of 20 milliseconds, in order to select appropriate bandwidth resources for data transmission with the network side. This results in higher power consumption and poor energy saving. In RRC disconnected mode, the terminal device does not need to perform channel measurements on the reference signal, resulting in lower power consumption and better energy saving. In RRC idle mode, the terminal device achieves