WO2022160315A1

WO2022160315A1 - Communication method and apparatus

Info

Publication number: WO2022160315A1
Application number: PCT/CN2021/074556
Authority: WO
Inventors: 陈磊; 李秉肇
Original assignee: 华为技术有限公司
Priority date: 2021-01-30
Filing date: 2021-01-30
Publication date: 2022-08-04

Abstract

The present application provides a communication method and apparatus, being able to solve the problem that a terminal device performs cell reselection after sending a radio resource control (RRC) message and releases from an inactive state to an idle state, thereby effectively reducing a data transmission delay, and improving data transmission efficiency and reliability. The invention is applicable to a 4G or 5G communication system, such as LTE and NR. Said method comprises: sending a first RRC message to a first network device (S401), and reselecting a cell of a second network device from a cell of a first network device (S402), wherein the terminal device remains in an inactive state.

Description

Communication method and device

technical field

The present application relates to the field of communication, and in particular, to a communication method and device.

Background technique

In the 5th generation (5G) communication system, there are three radio resource control (RRC) states for terminal equipment, which are RRC-connected state and RRC-idle state. state and RRC inactive state.

Among them, the terminal device in the connected state can perform data transmission with network devices, such as with a base station (basic station, BS), while the terminal device in the non-active state wants to perform data transmission with the network device. Enter connected state. That is to say, the terminal device in the inactive state needs to enter the connection state first, and then perform data transmission with the network device. In this way, unnecessary power consumption and signaling overhead will be caused. Therefore, in the 5G communication system, a data transmission method called "data early transmission" or "data forward transmission" is introduced, that is, the terminal device can perform data transmission with the network device without entering the connection state, which can effectively improve the Data transmission efficiency, reducing the energy consumption of terminal equipment.

SUMMARY OF THE INVENTION

The embodiments of the present application provide a communication method and device, which can effectively reduce data transmission delay and improve data transmission efficiency and reliability.

To achieve the above object, the application adopts the following technical solutions:

In a first aspect, a communication method is provided. The method includes sending a first radio resource control RRC message to a first network device, and reselection from a cell of the first network device to a cell of the second network device. Wherein, the terminal device remains in an inactive state.

Based on the method described in the first aspect, since the terminal device performs cell reselection after sending the first RRC message to the first network device, it can still remain in the inactive state, and will not be released to the idle state. As a result, the data transmission is interrupted and the data transmission delay increases, so that the terminal device can still directly use the inactive state to transmit data after cell reselection, so as to effectively reduce the data transmission delay and improve the data transmission efficiency and reliability.

In a possible design solution, the method described in the first aspect may further include: sending a second RRC message to the second network device. Wherein, the second RRC message may include: the first inactive wireless network temporary identifier I-RNTI. The first I-RNTI may be allocated by the third network device to the terminal device. The third network device may be an anchor network device of the terminal device. Wherein, the second RRC message may further include: the first truncated integrity message authentication code MAC-I. The first truncated MAC-I may be determined according to a cell configuration parameter of the third network device and the first key. The first key may be determined by calculating the NCC according to the first next-hop chain. The first NCC is allocated by the third network device to the terminal device.

It should be understood that since the anchor network device after the terminal device performs cell reselection is still the third network device, the resource overhead caused by switching the anchor network device can be avoided, and the communication efficiency can be further improved.

In another possible design solution, the method described in the first aspect may further include: before performing cell reselection, receiving the first information from the first network device. Wherein, the first information may include: the second I-RNTI and the second NCC. The second I-RNTI may be allocated by the first network device or the third network device for the terminal device. The second NCC may be allocated to the terminal device by the first network device or by the third network device. The third network device is the anchor network device of the terminal device.

Optionally, the method described in the first aspect may further include: sending a second RRC message to the second network device. The second RRC message may carry the second I-RNTI and the second truncated MAC-I. The second truncated MAC-I may be determined according to a cell configuration parameter of the first network device and the second key. The second key is determined according to the second NCC.

According to the process predefined in the protocol, if the terminal device does not perform cell reselection after sending the first RRC message, the first network device may send the first RRC message to the terminal device after the first RRC message, for example, after the data transmission ends or the connection state is restored. Send an RRC release message to indicate the end of data transmission or the end of data transmission in the connected state, and re-release the terminal device to the idle state or inactive state, such as releasing the terminal device to the inactive state, the I-RNTI and NCC. The difference is that in this application, the first information is sent to the terminal device before the RRC release message indicating the end of data transmission or the end of connection state data transmission is sent, and the second I-RNTI and the second NCC are sent by prepending. The terminal device is instructed to remain in the inactive state, so that the terminal device can continue to transmit data according to the pre-obtained second I-RNTI and the second NCC before and after cell reselection, so as to effectively improve the data transmission efficiency.

Optionally, the method of the first aspect may further include: receiving a third RRC message from the second network device. The third RRC message may be an RRC release message, where the third RRC message may include: a third I-RNTI and a third NCC. The third I-RNTI and the third NCC may be allocated by the second network device to the terminal device. The third I-RNTI may be different from the second I-RNTI, and/or the third NCC may be different from the second NCC. Alternatively, the third RRC message may further instruct the terminal device to use the second I-RNTI and the second NCC. In this way, the terminal device can be flexibly instructed to update or continue to use the original I-RNTI and/or NCC according to the actual application scenario. For example, if communication security needs to be guaranteed, the terminal device is instructed to use the updated I-RNTI and NCC. For another example, if the resource overhead needs to be reduced, the terminal device is instructed to use the original I-RNTI and NCC to avoid the resource overhead caused by updating the I-RNTI and/or NCC.

In a possible design solution, the method described in the first aspect may further include: sending a Packet Data Convergence Protocol PDCP status report to the second network device, so that the second network device can send the terminal device to the terminal device according to the PDCP status report. Data not received by the device. Wherein, when sending the RRC message, the terminal device can package and send the PDCP status report with the RRC message, thereby reducing signaling overhead and further improving communication efficiency.

It should be noted that the method described in the first aspect may be executed by a terminal device, a chip (system) or other components or components provided in the terminal device, and may also be executed by an apparatus including a terminal device. This is not limited.

In a second aspect, a communication method is provided. The method includes receiving a first RRC message from a terminal device. Wherein, if the terminal device performs cell reselection after sending the RRC message, the terminal device remains in an inactive state.

In a possible design solution, the terminal device is reselected from the cell of the first network device to the cell of the second network device, the method described in the second aspect may further include: sending the first data of the terminal device to the second network device .

In another possible design solution, the terminal device is reselected from the cell of the first network device to the cell of the second network device, the method described in the second aspect may further include: sending the first network device of the terminal device to the third network device. data. The third network device is an anchor network device of the terminal device. In this way, the third network device can forward the first data to the terminal device, thereby avoiding data loss of the terminal device, and further improving the reliability of communication.

In a possible design solution, the method described in the second aspect may further include: sending the first information to the terminal device. Wherein, the first information may include: the second I-RNTI and the second NCC. The second I-RNTI is allocated by the first network device or the third network device to the terminal device, the second NCC is allocated by the first network device or the third network device for the terminal device, the third The network device is the anchor network device of the terminal device.

Optionally, before sending the first information to the terminal device, the method described in the second aspect may further include: sending a context recovery request message to a third network device, and receiving a context recovery response message from the third network device. Wherein, the third network device may be: an anchor network device of the terminal device. The context restoration response message may include the first information. In this way, by multiplexing the context recovery response message to send the first information, the resource overhead is further reduced, and the communication efficiency is further improved.

In a possible design solution, the method described in the second aspect may further include: receiving a PDCP status report from the terminal device.

It should be noted that the method described in the second aspect may be executed by the first network device, or may be executed by a chip (system) or other components or components provided in the first network device, or may be executed by the first network device including the first network device. This is not limited in this application.

In addition, for the technical effect of the method described in the second aspect, reference may be made to the technical effect of the method described in the first aspect, which will not be repeated here.

In a third aspect, a communication method is provided. The method is applied to the second network device or a chip in the second network device. The method includes: sending the second information to the third network device, thereby receiving the first data from the first network device, so as to send the first data to the terminal device. Wherein, the second information is used to request the first data of the terminal device. The third network device may be an anchor network device of the terminal device. The first network device may reselection for the terminal device to a device corresponding to a cell in which the cell of the second network device resided before.

Based on the method described in the third aspect, by sending the second information to the third network device, the third network device can instruct the first network device to send the legacy first data to the second network device, so that the terminal device can finally obtain the the first data, thereby avoiding data loss caused by the terminal equipment due to cell reselection, thereby improving the reliability of communication.

In a possible design solution, the method described in the third aspect may further include: receiving a second RRC message from the terminal device. Wherein, the second RRC message may include: the first I-RNTI. The first I-RNTI may be allocated by the third network device to the terminal device. And, the second RRC message may further include: the first truncated MAC-I. The first truncated MAC-I may be determined according to the cell configuration parameters of the third network device and the first key, the first key may be determined according to the first NCC, and the first NCC may be the third network The device is assigned to the terminal device. Alternatively, the second RRC message may include: the second I-RNTI. The second I-RNTI may be allocated by the first network device or the third network device for the terminal device. And, the second RRC message may further include: a second truncated MAC-I. The second truncated MAC-I may be determined according to a cell configuration parameter of the first network device and a second key, the second key may be determined according to a second NCC, and the second NCC may be the first network The device or the third network device is allocated for the terminal device. The third network device may be an anchor network device of the terminal device.

In a possible design solution, the method described in the third aspect may further include: receiving a PDCP status report from the terminal device, and sending the PDCP status report to the third network device, so that the third network device can, according to the PDCP status report, Send data to a terminal device that the terminal device has not received. In this way, not only data loss can be avoided, but also redundant data can be avoided to further improve communication efficiency.

Optionally, sending the PDCP status report to the third network device may include: sending a context recovery request message to the third network device. Wherein, the context recovery request message may include a PDCP status report. In this way, the PDCP status report is sent by multiplexing the context recovery request message, which further reduces resource overhead and further improves communication efficiency.

It should be noted that the method described in the third aspect may be executed by the second network device, or may be executed by a chip (system) or other components or components provided in the second network device, or may be executed by the second network device including the second network device. This is not limited in this application.

In addition, for the technical effect of the method described in the third aspect, reference may be made to the technical effect of the method described in the first aspect and the second aspect, which will not be repeated here.

In a fourth aspect, a communication device is provided. The device includes: a transceiver module and a processing module. The transceiver module is configured to send the first radio resource control RRC message to the first network device. The processing module is used for the communication apparatus to perform reselection from the cell of the first network device to the cell of the second network device. Wherein, the communication device remains in an inactive state.

In a possible design solution, the transceiver module is further configured to send the second RRC message to the second network device. Wherein, the second RRC message may include: the first I-RNTI. The first I-RNTI may be allocated by the third network device to the communication apparatus. The third network device may be an anchor network device of the communication apparatus. Wherein, the second RRC message may further include: the first truncated MAC-I. The first truncated MAC-I may be determined according to a cell configuration parameter of the third network device and the first key. The first key may be determined according to the first NCC. The first NCC is allocated to the communication apparatus by the third network device.

In another possible design solution, before the processing module performs cell reselection, the transceiver module is further configured to receive the first information from the first network device. Wherein, the first information may include: the second I-RNTI and the second NCC. The second I-RNTI may be allocated by the first network device or the third network device for the communication apparatus. The second NCC may be allocated to the communication apparatus by the first network device or the third network device. The third network device may be an anchor network device of the communication apparatus.

Optionally, the transceiver module is further configured to send the second RRC message to the second network device. The second RRC message may carry the second I-RNTI and the second truncated MAC-I. The second truncated MAC-I may be determined according to a cell configuration parameter of the first network device and the second key. The second key may be determined according to the second NCC.

Optionally, the transceiver module is further configured to receive a third RRC message from the second network device. Wherein, the third RRC message may include: the third I-RNTI and the third NCC. The third I-RNTI and the third NCC may be allocated by the second network device for the communication apparatus. The third I-RNTI may be different from the second I-RNTI, and/or the third NCC may be different from the second NCC; alternatively, the third RRC message instructs the communication apparatus to use the second I-RNTI and the second NCC.

In a possible design solution, the transceiver module is further configured to send a packet data convergence protocol PDCP status report to the second network device.

Optionally, the transceiver module may include a receiving module and a sending module. Wherein, the receiving module is configured to implement the receiving function of the apparatus described in the fourth aspect. The sending module is configured to implement the sending function of the apparatus described in the fourth aspect.

Optionally, the apparatus according to the fourth aspect may further include a storage module, where the storage module stores programs or instructions. When the processing module executes the program or instruction, the apparatus can execute the communication method described in the first aspect.

It should be noted that the device described in the fourth aspect may be a terminal device, a chip (system) or other components or components that can be set in the terminal device, or a device including a terminal device. Not limited.

In addition, for the technical effect of the communication described in the fourth aspect, reference may be made to the technical effect of the method described in the first aspect, which will not be repeated here.

In a fifth aspect, a communication device is provided. The device includes: a receiving module. The receiving module is configured to receive the first RRC message from the terminal device. Wherein, if the terminal device performs cell reselection after sending the RRC message, the terminal device remains in an inactive state.

In a possible design solution, the terminal equipment is reselected from the cell of the communication apparatus to the cell of the second network equipment, and the apparatus according to the fifth aspect may further include: a sending module. The sending module is configured to send the first data of the terminal device to the second network device.

In another possible design solution, the terminal equipment is reselected from the cell of the communication apparatus to the cell of the second network equipment, and the apparatus according to the fifth aspect may further include: a sending module. The sending module is configured to send the first data of the terminal device to the third network device. The third network device may be an anchor network device of the terminal device.

In a possible design solution, the apparatus described in the fifth aspect may further include: a sending module. The sending module is configured to send the first information to the terminal device. Wherein, the first information may include: the second I-RNTI and the second NCC. The second I-RNTI may be allocated to the terminal device by the communication apparatus or the third network device. The second NCC may be allocated to the terminal device by the communication apparatus or the third network device. The third network device may be an anchor network device of the terminal device.

Optionally, before the sending module sends the first information to the terminal device, the sending module is further configured to send a context recovery request message to the third network device, and the receiving module is further configured to receive a context recovery response from the third network device. information. The third network device may be an anchor network device of the terminal device. The context restoration response message may include the first information.

In a possible design solution, the receiving module is further configured to receive the PDCP status report from the terminal device.

Optionally, the sending module and the receiving module can also be integrated into one module, such as a transceiver module. Wherein, the transceiver module is used to realize the sending function and the receiving function of the device.

Optionally, the apparatus of the fifth aspect may further include a processing module. Wherein, the processing module is used to realize the processing function of the device.

Optionally, the apparatus of the fifth aspect may further include a storage module, where the storage module stores programs or instructions. When the processing module executes the program or instruction, the apparatus can execute the method described in the second aspect.

It should be noted that the device described in the fifth aspect may be a network device, a chip (system) or other components or components that can be arranged in the network device, or a device including a network device. Not limited.

In addition, for the technical effect of the apparatus described in the fifth aspect, reference may be made to the technical effect of the method described in the second aspect, which will not be repeated here.

In a sixth aspect, a communication device is provided. The device includes: a receiving module and a sending module. The sending module is configured to send the second information to the third network device. The receiving module is configured to receive the first data from the first network device, so that the sending module sends the first data to the terminal device. Wherein, the second information is used to request the first data of the terminal device. The third network device may be an anchor network device of the terminal device. The first network device may be a device corresponding to a cell in which the terminal device reselection to the cell of the communication apparatus resides before.

In a possible design solution, the receiving module is further configured to receive the second RRC message from the terminal device. Wherein, the second RRC message may include: the first I-RNTI. The first I-RNTI may be allocated by the third network device to the terminal device. And, the second RRC message may further include: the first truncated MAC-I. The first truncated MAC-I may be determined according to a cell configuration parameter of the third network device and a first key, and the first key may be determined according to the first NCC. The first NCC may be allocated by the third network device to the terminal device. Alternatively, the second RRC message may include: the second I-RNTI. The second I-RNTI may be allocated by the first network device or the third network device for the terminal device. And, the second RRC message may further include: a second truncated MAC-I. The second truncated MAC-I may be determined according to a cell configuration parameter of the first network device and a second key, and the second key may be determined according to the second NCC. The second NCC may be allocated to the terminal device by the first network device or by the third network device. The third network device may be an anchor network device of the terminal device.

In a possible design solution, the receiving module is further configured to receive the PDCP status report from the terminal device. The sending module is further configured to send the PDCP status report to the third network device, so that the third network device can send data that the terminal device has not received to the terminal device according to the PDCP status report.

Optionally, the sending module is further configured to send a context recovery request message to the third network device. Wherein, the context recovery request message may include a PDCP status report.

Optionally, the apparatus of the sixth aspect may further include a processing module. Wherein, the processing module is used to realize the processing function of the device.

Optionally, the apparatus of the sixth aspect may further include a storage module, where the storage module stores programs or instructions. When the processing module executes the program or instruction, the apparatus can execute the method described in the third aspect.

It should be noted that the device described in the sixth aspect may be a network device, a chip (system) or other components or components that can be arranged in a network device, or a device including a network device. Not limited.

In addition, for the technical effect of the apparatus described in the sixth aspect, reference may be made to the technical effect of the method described in the third aspect, which will not be repeated here.

In a seventh aspect, a communication device is provided. The apparatus may comprise means for performing the method as described in the first aspect.

It should be understood that the communication apparatus described in the seventh aspect includes corresponding modules, units, or means for implementing the method described in the first aspect, and the modules, units, or means may be implemented by hardware, software, or by The hardware executes the corresponding software implementation. The hardware or software includes one or more modules or units for performing the functions involved in the above communication method.

In addition, for the technical effect of the communication apparatus described in the seventh aspect, reference may be made to the technical effect of the method described in the first aspect, which will not be repeated here.

In an eighth aspect, a communication device is provided. The apparatus may comprise means for performing the method as described in the second aspect or the third aspect.

It should be understood that the communication device described in the eighth aspect includes corresponding modules, units, or means for implementing the methods described in the second aspect or the third aspect, and the modules, units, or means may be implemented by hardware, and software Realize, or execute corresponding software through hardware. The hardware or software includes one or more modules or units for performing the functions involved in the above communication method.

In addition, for the technical effect of the communication apparatus described in the eighth aspect, reference may be made to the technical effect of the method described in the second aspect or the third aspect, which will not be repeated here.

In a ninth aspect, a communication device is provided. The apparatus may include: a processor and a memory, the processor and the memory are coupled, and the processor is configured to control the apparatus to implement the method as described in the first aspect.

Optionally, the apparatus of the ninth aspect may further include: a receiver and a transmitter. The receiver is used to implement the receiving function of the device, and the transmitter is used to implement the transmitting function of the device. Optionally, the transmitter and receiver can also be integrated into one device, such as a transceiver. Wherein, the transceiver is used to realize the sending function and the receiving function of the device.

It should be noted that the device described in the ninth aspect may be a terminal device, a chip (system) or other components or components that can be provided in the terminal device, or a device including a terminal device, which is not covered in this application. Do limit.

In addition, for the technical effect of the apparatus described in the ninth aspect, reference may be made to the technical effect of the method described in the first aspect, which will not be repeated here.

A tenth aspect provides a communication device. The apparatus may comprise: a processor and a memory, the processor and the memory being coupled, and the processor is configured to control the apparatus to implement the method as described in the second aspect or the third aspect.

Optionally, the apparatus of the tenth aspect may further include: a receiver and a transmitter. The receiver is used to implement the receiving function of the device, and the transmitter is used to implement the transmitting function of the device. Optionally, the transmitter and receiver can also be integrated into one device, such as a transceiver. Wherein, the transceiver is used to realize the sending function and the receiving function of the device.

It should be noted that the device described in the tenth aspect may be a network device, a chip (system) or other components or components that can be provided in a network device, or a device including a network device, which is not covered in this application. Do limit.

In addition, for the technical effect of the apparatus described in the tenth aspect, reference may be made to the technical effect of the method described in the second aspect or the third aspect, which will not be repeated here.

In an eleventh aspect, a communication device is provided. The apparatus may comprise: a processor and an interface circuit for receiving signals from other communication apparatuses other than the communication apparatus and transmitting to the processor or sending signals from the processor to other communication apparatuses than the communication apparatus An apparatus, a processor, is used to implement the method according to the first aspect by means of logic circuits or executing code instructions.

Optionally, the apparatus of the eleventh aspect may further include: a receiver and a transmitter. The receiver is used to implement the receiving function of the device, and the transmitter is used to implement the transmitting function of the device. Optionally, the transmitter and receiver can also be integrated into one device, such as a transceiver. Wherein, the transceiver is used to realize the sending function and the receiving function of the device.

Optionally, the apparatus of the eleventh aspect may further include a memory, where the memory stores programs or instructions. When the processor described in the eleventh aspect executes the program or the instruction, the apparatus can execute the method described in the first aspect.

It should be noted that the device described in the eleventh aspect may be a terminal device, a chip (system) or other components or components that can be provided in the terminal device, or a device including a terminal device. Not limited.

In addition, for the technical effect of the apparatus described in the eleventh aspect, reference may be made to the technical effect of the method described in the first aspect, which will not be repeated here.

A twelfth aspect provides a communication device. The apparatus may comprise: a processor and an interface circuit for receiving signals from other communication apparatuses other than the communication apparatus and transmitting to the processor or sending signals from the processor to other communication apparatuses than the communication apparatus An apparatus, a processor, is used to implement the method according to the second aspect or the third aspect by means of a logic circuit or executing code instructions.

Optionally, the apparatus of the twelfth aspect may further include: a receiver and a transmitter. The receiver is used to implement the receiving function of the device, and the transmitter is used to implement the transmitting function of the device. Optionally, the transmitter and receiver can also be integrated into one device, such as a transceiver. Wherein, the transceiver is used to realize the sending function and the receiving function of the device.

Optionally, the apparatus of the twelfth aspect may further include a memory, where the memory stores programs or instructions. When the processor of the twelfth aspect executes the program or the instruction, the apparatus can execute the method of the second aspect or the third aspect.

It should be noted that the device described in the twelfth aspect may be a network device, a chip (system) or other components or components that can be provided in a network device, or a device including a network device. Not limited.

In addition, for the technical effect of the apparatus described in the twelfth aspect, reference may be made to the technical effect of the method described in the second aspect or the third aspect, which will not be repeated here.

A thirteenth aspect provides a computer-readable storage medium. The computer-readable storage medium may include a computer program or instructions that, when run on a computer, cause the computer to perform the method as described in the first, second or third aspects.

A fourteenth aspect provides a computer program product. The computer program product may comprise a computer program or instructions which, when run on a computer, cause the computer to perform the method of the first, second or third aspect.

Description of drawings

FIG. 1 is a schematic diagram of state transition of a terminal device according to an embodiment of the present application;

FIG. 2 is a schematic flowchart of a deduction process of a key in an embodiment of the present application;

FIG. 3 is a schematic structural diagram of a communication system provided by an embodiment of the present application;

FIG. 4 is a schematic flowchart of a communication method provided by an embodiment of the present application;

5 is a schematic flowchart of a communication method provided by an embodiment of the present application in a first application scenario;

6 is a schematic flowchart of a communication method provided by an embodiment of the present application in a second application scenario;

FIG. 7 is a schematic structural diagram 1 of a communication device provided by an embodiment of the present application;

FIG. 8 is a second schematic structural diagram of a communication device according to an embodiment of the present application;

FIG. 9 is a third schematic structural diagram of a communication apparatus according to an embodiment of the present application.

Detailed ways

With reference to FIG. 1 , the technical terms involved in the technical solution of the present application are first introduced below.

1. Idle state

The idle state may be the state in which the terminal device is not connected to the network device. The idle state referred to in this application generally refers to the RRC idle state without special description.

Exemplarily, in the idle state, the terminal device may perform procedures such as public land mobile network (public land mobile network, PLMN) selection, cell selection, cell reselection, and system message broadcasting. Moreover, in the idle state, because the terminal device is not connected to the network device, does not access the network, does not occupy the service resources of the network device, and does not obtain the context and key of the terminal device, so the service data cannot be transmitted.

2. Connection state

The connected state may be the state in which the terminal device completes the connection with the network device. The connected state referred to in this application generally refers to the radio resource control RRC connected state unless otherwise specified.

Exemplarily, in the connected state, the terminal device may obtain the context and the key from the network device, so as to transmit service data by using the context and the key.

Optionally, the terminal device can enter the connected state from the idle state. For example, in the idle state, the terminal device can establish a connection with the network device by sending an RRC message, such as an RRC connection establishment request (RRC concept establish request) message, to the network device. The RRC is connected to enter the connected state. Or, optionally, the terminal device can also enter the connected state from the inactive state. For example, in the inactive state, the terminal device can send an RRC message to the network device, such as an RRC resume request (RRC Resume request) message, to resume and RRC connection between network devices, thus entering the connected state. In addition, in the connected state, the terminal device can also be released to the idle state or inactive state according to the RRC message sent by the network device, such as the RRC release message, thereby reducing resource overhead, reducing power consumption, and improving the terminal device. of endurance.

3. Inactive state

The inactive state may be an intermediate state between the connected state and the idle state. The inactive state referred to in this application generally refers to the RRC inactive state without special description, and may also be referred to as the "third state". ".

Exemplarily, after the terminal device is released from the connected state to the inactive state, the key can be deleted, but the context is retained, so that it can be quickly restored to the connected state subsequently. In the inactive state, the terminal device can perform cell reselection, and can also send an RRC message, such as an RRC recovery request message, to perform early data transmission, so as to reduce resource overhead and improve communication efficiency. In addition, in the inactive state, the terminal device can enter the idle state and delete the context after sending an RRC recovery request message, such as receiving an RRC release message.

4. Key deduction

In the inactive state or the connected state, in order to ensure safe data transmission between the terminal device and the network device. Both terminal equipment and network equipment need to perform key derivation to ensure that the key used for data encryption can be continuously updated to ensure the security of data transmission.

Specifically, with reference to FIG. 2 , and taking a terminal device as an example, the key derivation process is described in detail.

According to the flow shown in FIG. 2 , the terminal device can perform key deduction by using the algorithm in the context of the terminal device. For example, the terminal device may obtain the key K _AMF from the core network in advance, use the key K _AMF to deduce the initial key K _gNB for key deduction, and use the key K _AMF and the initial key K _gNB to deduce Show the next hop parameter (NH) used for key derivation, referred to here as NH1. Further, the terminal device may associate a preset next hop chaining count (NCC) 0 with a value of 0 with the initial keys K _gNB and NH1 respectively. In this way, after receiving the NCC from the network device, the terminal device can determine whether the value of the NCC and the above-mentioned NCC0 are the same. If the same, the terminal device performs horizontal deduction according to the initial key K _gNB associated with NCC0, otherwise, performs vertical deduction according to NH1 associated with NCC0, thereby determining the latest key. The following describes the process of horizontal deduction and vertical deduction respectively.

Horizontal deduction:

If the terminal device receives the above NCC0 from the network device, it can perform horizontal deduction, that is, according to the initial key K _gNB (the initial key K _gNB can be considered as K _gNB1 ), the physical cell identity of the cell where the terminal device currently resides (physical cell identifier, PCI) and carrier frequency, deduce the key K _gNB2 . In this way, the pair of K _gNB and NH saved by the terminal device can be updated from the initial keys K _gNB and NH1 to the keys K _gNB2 and NH1, and the association relationship of NCC0 can be updated as: NCC0 is associated with the keys K _gNB2 and NH1 respectively . Then, the terminal device can deduce the key K_RRCint, the key K_RRCenc, the key K_UPenc and the key K_UPint according to the key K _gNB2 . Among them, the key K_Upint and the key K_RRCint can be used for data integrity protection, and the key K_RRCenc and the key K_UPenc can be used for data encryption.

Afterwards, if the terminal device receives the above-mentioned NCC0 from the network device again, it can continue to perform horizontal deduction, that is, deduce the key K _gNB3 according to the key K _gNB2 , the PCI and carrier frequency of the cell where the terminal device currently resides. In this way, the pair of K _gNB and NH saved by the terminal device can be updated from the keys K _gNB2 and NH1 to the keys K _gNB3 and NH1, and the association relationship of NCC0 can also be updated as: NCC0 is associated with the keys K _gNB3 and NH1 respectively. . Then, the terminal device can deduce the key K_RRCint, the key K_RRCenc, the key K_UPenc and the key K_UPint according to the key K _gNB3 , and delete the key K_RRCint, the key K_RRCenc, the key K_UPenc and the key K_UPint derived last time , and so on.

Vertical play:

If the terminal device receives the NCC2 from the network device, and the value of the NCC2 is 2, which is different from the value of the NCC0 of 0, the vertical deduction can be performed, that is, the NH2 can be deduced according to the keys _KAMF and NH1. And according to the key NH1, the PCI and carrier frequency of the cell where the terminal device currently resides, the key K _{gNB4 is deduced} . In this way, the pair of K _gNB and NH stored by the terminal device can be updated from the initial keys K _gNB and NH1 to the keys K _gNB4 and NH4, and the association relationship can also be updated so that NCC2 is associated with the keys K _gNB4 and NH2 respectively. Then, the terminal device can deduce the key K_RRCint, the key K_RRCenc, the key K_UPenc and the key K_UPint according to the key K _gNB4 .

After that, if the terminal device receives NCC3 from the network device again, and the value of NCC3 is 3, which is different from the value of NCC2 of 2, it can continue to perform vertical deduction, that is, it can be deduced according to the keys K _AMF and NH2. Perform NH3, and deduce the performance key K _gNB7 according to NH2, the PCI and carrier frequency of the cell where the terminal device currently resides. In this way, a pair of K _gNB and NH saved by the terminal device can be updated from K _gNB4 and NH2 to keys K _gNB7 and NH3, and the association relationship can also be updated so that NCC3 is associated with keys K _gNB7 and NH3 respectively. Then, the terminal device can deduce the key K_RRCint, the key K_RRCenc, the key K_UPenc and the key K_UPint according to the key K _gNB7 , and delete the key K_RRCint, the key K_RRCenc, the key K_UPenc and the key that were previously derived K_UPint, and so on.

All in all, since each NCC can be associated with a pair of NH and K _gNB , for example, NCC0 can associate the initial key K _gNB and NH1 or associate K _gNB2 and NH1, NCC2 can associate K _gNB4 and NH2 or associate K _gNB5 and NH2, NCC3 can be associated with K _gNB7 and NH3 or associated with K _gNB8 and NH3. In this way, the terminal device can quickly perform horizontal deduction or vertical deduction according to a pair of NH and K _gNB associated with NCC to ensure the deduction efficiency of the key.

5. Cell reselection

As mentioned above, in the inactive state or the idle state, the terminal device can reselect to another cell from the cell it is currently camping on, such as reselecting to a cell with better signal and completing the camping in the reselected cell. The cell reselection may include intra-site reselection and inter-site reselection. Intra-site reselection refers to terminal equipment reselection from one cell of the same base station to another cell, while inter-site reselection refers to terminal equipment reselection from a cell of one base station to a cell of another base station.

Further, if the terminal device is in the inactive state and performs cell reselection after sending the RRC message, the terminal device will be released from the inactive state to the idle state, thereby causing data transmission in the inactive state to be interrupted, thereby affecting data transmission. Efficiency and reliability. After the data transmission is interrupted, since the terminal device can only retransmit when it enters the connected state next time, the data transmission delay will also be increased.

The technical solutions in the present application will be described below with reference to the accompanying drawings.

The technical solutions of the embodiments of the present application can be applied to various communication systems, such as a wireless fidelity (WiFi) system, a vehicle-to-everything (V2X) communication system, and a device-todevie (D2D) communication system. Communication systems, Internet of Vehicles communication systems, 4th generation (4G) mobile communication systems, such as long term evolution (LTE) systems, worldwide interoperability for microwave access (WiMAX) communication systems, 5th generation (5G) mobile communication systems, such as new radio (NR) systems, and future communication systems, such as 6th generation (6G) mobile communication systems.

This application will present various aspects, embodiments, or features around a system that may include a plurality of devices, components, modules, and the like. It is to be understood and appreciated that the various systems may include additional devices, components, modules, etc., and/or may not include all of the devices, components, modules, etc. discussed in connection with the figures. In addition, combinations of these schemes can also be used.

In addition, in the embodiments of the present application, words such as "exemplarily" and "for example" are used to represent examples, illustrations or illustrations. Any embodiment or design described in this application as "exemplary" should not be construed as preferred or advantageous over other embodiments or designs. Rather, the use of the word example is intended to present a concept in a concrete way.

In the embodiments of the present application, "information", "signal", "message", "channel", and "signaling" may sometimes be used interchangeably. It should be noted that, When not emphasizing their differences, their intended meanings are the same. "of", "corresponding, relevant" and "corresponding" can sometimes be used interchangeably. It should be pointed out that when the difference is not emphasized, the meanings they intend to express are the same.

In the embodiments of the present application, sometimes _a subscript such as W1 may be mistakenly written in a non-subscript form such as W1. When the difference is not emphasized, the meaning to be expressed is the same.

The network architecture and service scenarios described in the embodiments of the present application are for the purpose of illustrating the technical solutions of the embodiments of the present application more clearly, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. The evolution of the architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

To facilitate understanding of the embodiments of the present application, firstly, a communication system applicable to the embodiments of the present application is described in detail by taking the communication system shown in FIG. 3 as an example. Exemplarily, FIG. 3 is a schematic structural diagram of a communication system to which the communication method provided by the embodiment of the present application is applied.

As shown in FIG. 3 , the communication system may include: at least one network device, such as a first network device, a second network device and a third network device, and at least one terminal device.

Wherein, the above-mentioned first network device, second network device and third network device may be collectively referred to as network device, and the network device is located on the network side of the above-mentioned communication system and has a wireless transceiver function or a chip that can be installed in the device. or system-on-chip. The network devices include but are not limited to: access points (APs) in wireless fidelity (WiFi) systems, such as home gateways, routers, servers, switches, bridges, etc., evolved Node B (evolved Node B (eNB), Radio Network Controller (RNC), Node B (Node B, NB), Base Station Controller (BSC), Base Transceiver Station (BTS), Home Base station (for example, home evolved NodeB, or home Node B, HNB), baseband unit (BBU), wireless relay node, wireless backhaul node, transmission point (transmission and reception point, TRP or transmission point, TP) etc., it can also be 5G, such as a gNB in a new radio (NR) system, or a transmission point (TRP or TP), one or a group (including multiple antenna panels) antennas of a base station in a 5G system The panel, alternatively, can also be a network node that constitutes a gNB or a transmission point, such as a baseband unit (BBU), or a distributed unit (DU), a roadside unit (RSU) with base station functions, etc. .

The above-mentioned terminal equipment is a terminal that is connected to the above-mentioned communication system and has a wireless transceiver function, or a chip or a chip system that can be provided in the terminal. The terminal equipment may also be referred to as user equipment (UE), access terminal, subscriber unit, subscriber station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, User Agent or User Device. The terminal device in the embodiment of the present application may be a mobile phone, a tablet computer, a computer with a wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless device in industrial control Terminal, wireless terminal in unmanned driving, wireless terminal in telemedicine, wireless terminal in smart grid, wireless terminal in transportation safety, wireless terminal in smart city, wireless terminal in smart home, in-vehicle terminal, terminal with terminal Functional RSU et al. The terminal device of the present application may also be an on-board module, on-board module, on-board component, on-board chip or on-board unit built into the vehicle as one or more components or units. The vehicle-mounted component, the vehicle-mounted chip or the vehicle-mounted unit can implement the communication method provided in this application.

It should be noted that the communication method provided by the embodiment of the present application can be applied between any two, three or four nodes shown in FIG. 3 , such as between a terminal device and a first network device, and the specific implementation can refer to The following method embodiments will not be repeated here.

It should be noted that the solutions in the embodiments of the present application may also be applied to other communication systems, and the corresponding names may also be replaced by the names of corresponding functions in other communication systems.

It should be understood that FIG. 3 is only a simplified schematic diagram for easy understanding, and the communication system may further include other network devices and/or other terminal devices, which are not shown in FIG. 3 .

The communication method provided by the embodiment of the present application will be described in detail below with reference to FIG. 4 to FIG. 6 .

Exemplarily, FIG. 4 is a schematic flowchart of a communication method provided by an embodiment of the present application. The method may be performed by a terminal device, a chip (system) or other components or components in the terminal device, or an apparatus including the terminal device, the first network device, a chip (system) or other components or components in the first network device, or An apparatus including the first network device, a second network device (not shown in FIG. 3 ), a chip (system) or other component or component in the second network device, or an apparatus including the second network device, and a third network The device (not shown in FIG. 3 ), the chip (system) or other components or components in the third network device, or the apparatus including the third network device cooperate and execute, so as to realize the connection between any number of nodes shown in FIG. 3 Communication.

For ease of description, "terminal equipment, chips (systems) or other components or components in terminal equipment, or devices including terminal equipment" are collectively referred to as "terminal equipment" hereinafter, and "the first network equipment, the first network equipment in the first network equipment" are collectively referred to as "terminal equipment". The chip (system) or other components or components of the second network device, or the device including the first network device” are collectively referred to as “the first network device”, and the “second network device, the chip (system) or other components in the second network device or components, or devices including the second network equipment” are collectively referred to as “second network equipment”, and “third network equipment, chips (systems) or other components or components in third network equipment, or including third network equipment” "devices" are collectively referred to as "third network equipment".

Further, as shown in Figure 4, the communication method may include the following steps:

S401, a terminal device sends a first radio resource control RRC message to a first network device, and the first network device receives the first RRC message from the terminal device.

Exemplarily, the first RRC message may be an RRC resume request message (RRC resume request message). Wherein, the first RRC message may be used for the terminal device to transmit the second data in an inactive state. The second data may be data used by the terminal device for early transmission.

In a possible implementation manner, the terminal device may package the first RRC message and the second data to generate a protocol data unit (protocol data unit, PDU) of the media access control sublayer protocol (media access control, MAC) layer, Then, it is sent to the first network device through the physical layer, so as to realize early data transmission. Or, in another possible implementation manner, the second data may be included in the first RRC message. It should be understood that the first RRC message may not only be used for the above-mentioned data transmission, but also may be used for the terminal device to request to restore from the inactive state to the connected state. For example, the terminal device may send the first RRC message alone without carrying the second data, so as to request to restore from the inactive state to the connected state.

Wherein, the first RRC message may include: a first inactive wireless network temporary identifier (inactive-radio network temporary identifier, I-RNTI), and a third truncated (short) integrity message authentication code (message authentication code for integrity, MAC-I).

The first I-RNTI may be allocated by the third network device for the terminal device, which corresponds to the context of the terminal device and indicates that the context is stored in the third network device. The third network device may be a different network device from the first network device, and is the anchor network device of the terminal device, that is, the terminal device is released to the inactive state by the third network device, or the third network device is a terminal device The network device to which the last cell before entering the inactive state belongs. The third truncated MAC-I can be used for security verification. It is calculated by the terminal device using the integrity protection algorithm in the stored security context, the third key and the first related parameters, and the length can be 16 bits. .

The above-mentioned third key may be K_RRCint ₁ . The above-mentioned first related parameters may include: a radio network temporary identifier (cell radio network temporary identifier, C-RNTI) used by the terminal device when camping on the cell of the third network device, the PCI of the cell of the third network device, the first network The cell identity document (cell-ID) of the cell of the device. The cell of the first network device is the cell where the terminal device currently resides.

Exemplarily, before sending the first RRC message, the terminal device may also camp on or enter the connected state in the cell of the third network device. In this way, the third network device may send a fourth RRC message to the terminal device, such as sending an RRC release message. The fourth RRC message may carry the first I-RNTI and the first NCC allocated by the third network device to the terminal device.

Wherein, if the terminal device receives the fourth RRC message from the third network device in the connected state, it is released from the connected state to the inactive state, and deletes K_RRCenc1, K_UPenc1, and K_Upint1 deduced last time, but retains the terminal device context and the key K_RRCint1 (third key) derived last time, so as to be used when the first RRC message is sent subsequently. Alternatively, if the terminal device receives the fourth RRC message in the inactive state, it continues to remain in the inactive state. In addition, the terminal device may also determine whether the first NCC in the fourth RRC message is associated with a pair of NH and KgNB saved by the terminal device. If associated, the terminal device may retain the KgNB1 for subsequent execution of the horizontal deduction; otherwise, the terminal device may delete the KgNB1 for subsequent execution of the vertical deduction.

Further, if the terminal device reselects from the cell of the third network device to the cell of the first network device, it remains in the inactive state. On this basis, the terminal device may send the above-mentioned first RRC message to the first network device. Wherein, after sending the first RRC message, the terminal device may start a timer (timer) with a predetermined duration, so that the terminal device can determine whether the data transmission ends or whether to return to the connected state. For example, if the terminal device receives a response message from the first network device before the timing ends, or the terminal device does not receive the response message after the timing ends, it is determined that the data transmission ends or the connection state is restored. The response message may be an RRC release message. In addition, the terminal device can also use the algorithm in the context of the terminal device and the first NCC to perform horizontal deduction or vertical deduction, so as to obtain the latest key K _gNB2 to derive K_RRCint ₂ (the first key K gNB2 ) according to the key K _gNB2 ), the key K_RRCenc ₂ , the key K_UPenc ₂ , and the key K_UPint ₂ , and delete the key K_RRCint ₁ (the third key) derived last time.

It should be understood that after deriving K _gNB2 , the terminal device may continue to retain the first NCC, so that the first NCC can be used in subsequent horizontal deduction.

Further, if the first network device receives the first RRC message, it can determine that the anchor network device is the third network device according to the first I-RNTI in the first RRC message, so as to send the context recovery to the third network device. A request (retrieve UE context rquest) message, for example, a context recovery request message may be sent to the third network device through the Xn interface. The context recovery request message may carry the first I-RNTI, the third truncated MAC-I, and the PCI of the cell of the first network device. Correspondingly, the third network device can determine whether there is a context corresponding to the first I-RNTI (the context of the terminal device) according to the context recovery request message, and determine the third truncated MAC-I and the fourth truncated MAC-I Whether the MAC-I is consistent. Wherein, the fourth truncated MAC-I may be determined by the third network device according to the above-mentioned first relevant parameter and the above-mentioned third key.

If the third network device determines that there is no context corresponding to the first I-RNTI, and/or the third truncated MAC-I is inconsistent with the fourth truncated MAC-I, it means that the verification fails, and the process of the method ends . If the third network device determines that there is a context corresponding to the first I-RNTI, and the third truncated MAC-I is consistent with the fourth truncated MAC-I, it indicates that the verification is passed. In this way, the third network device can use the algorithm in the context and the first NCC to perform horizontal deduction or vertical deduction to obtain a key corresponding to the first key, and send a context recovery response (retrieve UE) to the first network device context response) message.

The key corresponding to the first key may be K _gNB2 , or may also be the key K_RRCint ₂ (the first key), the key K_RRCenc2 , the key K_UPenc2 and the key K_UPint derived from the K _gNB2 ₂ . Wherein, if the key corresponding to the first key is K _gNB2 , the first network device can use the K _{gNB2 to} deduce the key K_RRCint ₂ , the key K_RRCenc ₂ , the key K_UPenc ₂ , and the key K_UPint ₂ again. The context recovery response message may carry the corresponding key, the first NCC and the context of the terminal device, so that the first network device can communicate with the terminal device according to the corresponding key, the first NCC and the context of the terminal device.

In addition, if the third network device stores the first data of the terminal device, after the verification is passed, the third network device can send the first data to the first network device, so that the first network device can forward the first data to the terminal device. data. The first data may be service data of the terminal device received by the third network device from a core network element, such as a user plane function (user plane function, UPF) network element.

Further, if the first network device receives the context recovery response message from the third network device, then the context of the terminal device in the context recovery response message can be returned to the access and mobility management function (access and mobility management function, AMF) according to the context of the terminal device in the context recovery response message. ) network element (not shown in FIG. 4 ) sends a path switch request message. In this way, the AMF network element can modify the bearer (breaer) on the UPF network element (not shown in FIG. 4 ) according to the path switching request message, for example, the bearer can be changed from “terminal device→third network device→UPF network element” ” is modified to “terminal device→first network device→UPF network element”, so that the first network device can receive the first data from the terminal device of the core network and forward it to the terminal device. Then, the AFM network element may send a path switch request acknowledgment (path switch request ACK) message to the first network device to inform the first network device that the path switch is completed. Wherein, since the first network device obtains the context of the terminal device, it can be considered that the anchor network device of the terminal device is changed from the third network device to the first network device.

Further, if the first network device receives the path switching request confirmation message from the AMF network element, and the terminal device is still resident in the cell of the first network device, it can send (UE context rlease message) to the third network device, So that the third network device releases the context of the terminal device and the first I-RNTI to save resources; otherwise, it is not necessary to send the terminal device context release message to the third network device, so that the terminal device can be reselected to the second network device (specifically Please refer to the following cell in S402, step 1), the second network device can find the third network device according to the first I-RNTI, and obtain the context of the terminal device from the third network device. In addition, if the first network device receives the above-mentioned second data, it may send the second data to the UPF network element (not shown in FIG. 4 ) after receiving the path switching request confirmation message.

It should be understood that the above content is introduced by taking the inter-site cell reselection as an example, that is, the first network device and the third network device are different network devices, but this is not a limitation. For example, if the terminal device performs cell reselection in the station of the third network device, the third network device may receive the above-mentioned first RRC message from the terminal device, and use the above-mentioned first key and the pre-stored context of the terminal device , communicate with the terminal device normally.

S402, the terminal device reselects from the cell of the first network device to the cell of the second network device.

Exemplarily, if the terminal device performs cell reselection, such as reselection from the cell of the first network device to the cell of the second network device, before the data transmission ends or is restored to the connected state, the terminal device remains in the inactive state instead of will be released to idle state. The second network device and the first network device may be different network devices.

The specific implementation of the terminal device performing cell reselection before the data transmission ends or before returning to the connected state and remains in the inactive state may refer to the following related content in the second implementation scenario.

Optionally, in the first implementation scenario of the embodiment shown in FIG. 4 , after S402, the method may further include: Step 1, the terminal device sends a second RRC message to the second network device, and the second network device sends a second RRC message to the second network device. A second RRC message from the terminal device is received.

Wherein, the second RRC message may be an RRC recovery request message, including: the above-mentioned first I-RNTI and the first truncated MAC-I. The first truncated MAC-I can be used for security verification, and is determined by the terminal device according to the second related parameter and the above-mentioned first key, and the length can also be 16 bits.

The above-mentioned second related parameters may include: C-RNTI used by the terminal device when camping on the cell of the first network device, PCI of the cell of the first network device, and cell-ID of the cell of the second network device. The cell of the second network device is the cell where the terminal device currently resides.

The second RRC message may be used by the terminal device to transmit third data in an inactive state. The third data may be data used by the terminal device for early transmission, and may be the same as or different from the second data.

In a possible implementation manner, the terminal device may package the second RRC message and the third data to generate a PDU of the MAC layer, and then send it to the PDU through the physical layer, thereby realizing early data transmission. Or, in another possible implementation manner, the third data may also be included in the second RRC message. It should be understood that the second RRC message may not only be used for the above-mentioned data transmission, but also may be used for the terminal device to request to restore from the inactive state to the connected state. For example, the terminal device may send the second RRC message alone without carrying the third data, so as to request to restore from the inactive state to the connected state.

In addition, after the terminal device sends the second RRC message, it can also use the algorithm in the context of the terminal device and the pre-reserved first NCC to perform horizontal deduction, so as to obtain the key Kg _NB3 , which can be deduced according to the key Kg _NB3 K_RRCint ₃ , key K_RRCenc ₃ , key K_UPenc ₃ , and key K_UPint ₃ , and delete key K_RRCint ₂ (first key), key K_RRCenc ₂ , key K_UPenc ₂ , and key K_UPint ₂ from the last derivation .

Further, if the second network device receives the second RRC message, it can determine that the anchor network device is the third network device according to the first I-RNTI in the second RRC message, so as to send the context recovery to the third network device. For the request message, for example, a context recovery request message may be sent to the third network device through the Xn interface. The context recovery request message may carry the first I-RNTI, the first truncated MAC-I, and the PCI of the cell of the second network device. In this way, the third network device can determine whether there is a context corresponding to the first I-RNTI (the context of the terminal device) according to the context recovery request message, and determine the first truncated MAC-I and the fifth truncated MAC-I Is I consistent. The fifth truncated MAC-I may be determined by the third network device according to the second related parameter and the first key.

If the third network device determines that the first truncated MAC-I is inconsistent with the fifth truncated MAC-I, it indicates that the verification fails, and the process of the method ends. If the third network device determines that the first truncated MAC-I is consistent with the fifth truncated MAC-I, it indicates that the verification is passed. In this way, the third network device can use the algorithm in the context and the first NCC to perform horizontal deduction to obtain a key corresponding to K_RRCint ₃ , and send a context recovery response message to the second network device. The corresponding key may be Kg _NB3 , or may also be the key K_RRCint ₃ , the key K_RRCenc ₃ , the key K_UPenc ₃ , and the key K_UPint ₃ derived by using the Kg _NB3 . Wherein, if the corresponding key is KgNB ₃ , the second network device can use the KgNB ₃ to deduce the key K_RRCint ₃ , the key K_RRCenc ₃ , the key K_UPenc ₃ and the key K_UPint ₃ again. In addition, the context recovery response message may carry the corresponding key, the first NCC and the context of the terminal device, so that the second network device can communicate with the terminal device according to the corresponding key, the first NCC and the context of the terminal device.

It should be understood that in the above step 1, since the anchor network device after the terminal device performs cell reselection is still the third network device, the resource overhead caused by switching the anchor network device can be avoided, and the communication efficiency can be further improved.

Optionally, in the first implementation scenario of the embodiment shown in FIG. 4 , after step 1, the method may further include: step 2, the second network device sends second information to the third network device, and the third The network device receives the second information from the second network device.

Wherein, the second information can be used to request the first data of the terminal device, and can be carried in an address indication (address indication) message, including one or more of the following: the identification of the terminal device, the first address or the second address. Wherein, according to the relevant introduction in S401 above, it can be known that the first data may be data obtained by the first network device from the third network device and/or from the core network. The first address may be an address allocated by the second network device for a quality of service (quality of service, QoS) flow of the terminal device, and the second address may be a data radio bearer (data radio bearer) mapped by the second network device for the QoS flow, DRB) assigned address.

Wherein, after receiving the context recovery response message from the terminal device, the second network device may send the second information to the third network device according to the context in the context recovery response message, for example, may send the second information to the third network device through the Xn interface An address indication message carrying the second information. In this way, the third network device may instruct the first network device to send the first data to the second network device according to the second information.

In a possible implementation manner, after receiving the second information, the third network device may forward the second information to the second network device, such as forwarding the address indication carrying the second information to the second network device through the Xn interface. information. In this way, after receiving the second information, the second network device can find the corresponding first data according to the identifier of the terminal device in the second information. Correspondingly, the first network device may send the data corresponding to the QoS flow in the first data to the second network device according to the first address, and/or send the data corresponding to the DRB in the first data to the second network device according to the second address .

In another possible implementation manner, after receiving the second information, the third network device may send the address of the third network device and the identifier of the terminal device to the second network device. Wherein, the address of the third network device may be an internet protocol (internet protocol, IP) address, the address and the identifier may be carried in an address indication message, and the address indication message may be sent to the first network device through the Xn interface. Correspondingly, after receiving the address and the identifier, the second network device can find the corresponding first data according to the identifier, and send the first data to the third network device according to the address. In this way, the third network can send the data corresponding to the QoS flow in the first data to the sending second network device according to the first address in the second information, and/or, according to the second address in the second indication information, Send the data corresponding to the DRB in the first data to the sending second network device.

Finally, the second network device receives the first data from the first network device, and sends the first data to the terminal device to implement data retransmission, thereby avoiding data loss.

Optionally, in the second implementation scenario of the embodiment shown in FIG. 4 , after S401 and before S402, the method may further include: Step 3, the first network device sends the first information to the terminal device, and the terminal The device receives the first information from the first network device.

Exemplarily, the first information may include: the second I-RNTI and the second NCC.

The second I-RNTI may be allocated by the first network device or the third network device for the terminal device, corresponds to the context of the terminal device and indicates that the context is stored in the first network device, and is the same as the above-mentioned first I-RNTI or different. The second NCC may be used for key derivation, is allocated by the first network device or the third network device for the terminal device, and is the same as or different from the above-mentioned first NCC.

After receiving the first information, if the terminal device performs cell reselection before data transmission ends or before returning to the connected state, the terminal device remains in the inactive state.

Optionally, the first information is carried in the RRC release message, and at this time, the first information may further include: indication information. The indication information may be a field, such as a field with a length of one bit, used to instruct the terminal device to store the second I-RNTI and the second NCC after receiving the RRC release message, without terminating the current RRC connection and continuing the current data transfer process.

Exemplarily, the first information may be generated in two ways, which may be generated by a third network device, or may also be generated by a first network device. They are introduced separately below.

a. The first network device generates

In this embodiment of the present application, if the first network device receives the first RRC message from the terminal device, it may generate a first message carrying the first information, and send the first message to the terminal device, so as to send the first message to the terminal device. Send the first message. Wherein, the first message can be any of the following: RRC message, such as RRC release message, media access control address control element (media access control address control element, MAC CE) message or downlink control information (downlink control information) , DCI) message.

b. The third network device generates

With reference to the relevant introduction in the above S401, after verifying the passage of the first I-RNTI and the first truncated MAC-I, the third network device may generate the first information, and send the first information to the first network device carrying the first information The context recovery response message. The first information may be directly carried in the context recovery response message, or the first information may be carried in a fifth RRC message, such as an RRC release message, and the fifth RRC message may be further encapsulated in the context recovery response message . Correspondingly, the context recovery response message received by the first network device may include the first information or include a fifth RRC message carrying the first information. In this way, by parsing the context recovery response message, the first network device can not only obtain the deduced key and the context of the terminal device, but also directly obtain the first information or the fifth RRC message carrying the first information, further reducing resource overhead and further improve communication efficiency.

Further, if the first network device directly obtains the above-mentioned fifth RRC message from the context recovery response message, it can directly forward the fifth RRC message to the terminal device. If the first network device directly obtains the above-mentioned first information from the context recovery response message, it may generate a second message carrying the first information, and send the second message to the terminal device. Wherein, the second message and the first message may be the same or different messages, and the second message may also be any of the following: an RRC message, such as an RRC release message, a MAC CE message, or a DCI message.

In this way, the terminal device can continue to remain in the inactive state after reselection to the cell of the second network device.

It should be noted that, according to the existing protocol flow, if the terminal device does not perform cell reselection after sending the first RRC message, the first network device may, after the first RRC message, for example, end data transmission or return to the connected state. Afterwards, an RRC release message is sent to the terminal device, so as to indicate the end of data transmission or return to the connected state through the I-RNTI and NCC carried in the RRC release message. The difference is that in this application, the first network device sends the first information to the terminal device before the data transmission ends or returns to the connected state, and instructs the terminal device by sending the second I-RNTI and the second NCC in advance. Remaining in the inactive state, so that the terminal device can continue to transmit data according to the second I-RNTI and the second NCC obtained in advance before and after performing cell reselection, so as to effectively improve the data transmission efficiency. Of course, after sending the first information, if the terminal device does not perform cell reselection, the first network device may still send an RRC release message to the terminal device according to the existing protocol flow after data transmission ends or after the data transmission is restored to the connected state, so as to Indicates that the data transfer is over or the connection state has been restored.

In addition, the above implementation manner in which the terminal device is kept in the inactive state is based on the message indication as an example, but it is not limited. For example, the terminal device can also be automatically kept in the inactive state in a way predefined by the protocol, without the need for a network device. give instructions.

Optionally, in the second implementation scenario of the embodiment shown in FIG. 4 , after S402, the method may further include: Step 4, the terminal device sends a second RRC message to the second network device, and the second network device A second RRC message from the terminal device is received.

Exemplarily, the second RRC message may include: the above-mentioned second I-RNTI and the second truncated MAC-I. The second truncated MAC-I may be determined by the terminal device according to the above-mentioned second related parameters and the second key, and the length may be 16 bits.

The second key may be determined by the terminal device according to the second NCC in the first information and the algorithm in the context of the terminal device. For example, the terminal device may use the algorithm in the context of the terminal device and the second NCC to execute the level of or vertical deduction, so as to obtain the key Kg _NB4 to deduce K_RRCint ₄ (the second key), the key K_RRCenc ₄ , the key K_UPenc ₄ and the key K_UPint ₄ according to the key Kg _NB4 , and delete the last deduction key K_RRCint ₂ (first key), key K_RRCenc ₂ , key K_UPenc ₂ and key K_UPint ₂ .

In addition, after the terminal device sends the second RRC message, it can also perform horizontal deduction by using the context of the terminal device and the second NCC, so as to obtain the key Kg _NB5 , so as to _deduce K_RRCint ₅ , the key K_RRCenc 5 , the key K_RRCenc ₅ , key K_UPenc ₅ and key K_UPint ₅ , and delete K_RRCint ₄ (second key), key K_RRCenc ₄ , key K_UPenc ₄ and key K_UPint ₄ .

Further, if the second network device receives the second RRC message from the terminal device, it may determine that the anchor network device is the first network device according to the second I-RNTI in the second RRC message. In this way, the first network device may send a context recovery request message to the first network device, such as sending a context recovery request message to the first network device through the Xn interface. The context recovery request message may carry the second I-RNTI, the second truncated MAC-I, and the PCI of the cell of the second network device. Correspondingly, the first network device can determine whether there is a context corresponding to the second I-RNTI (the context of the terminal device) according to the context recovery request message, and determine the second truncated MAC-I and the sixth truncated MAC-I Is I consistent. The sixth truncated MAC-I may be determined by the first network device according to the above-mentioned second related parameters and the second key, and the second key may be determined by the first network device according to the algorithm in the context of the terminal device and the second key. 2. NCC determined.

If the first network device determines that there is no context corresponding to the second I-RNTI, and/or the second truncated MAC-I is inconsistent with the sixth truncated MAC-I, it means that the verification fails, and the process of the method ends. . If the first network device determines that there is a context corresponding to the second I-RNTI, and the second truncated MAC-I is consistent with the sixth truncated MAC-I, it indicates that the verification is passed. In this way, the first network device may also perform horizontal deduction by using the context and the second NCC to obtain a key corresponding to K_RRCint ₅ , and send a context recovery response message to the second network device. The key corresponding to K_RRCint ₅ may be K _gNB5 , or the key K_RRCint ₅ , the key K_RRCenc ₅ , the key K_UPenc ₅ , and the key K_UPint ₅ derived by using the K _gNB5 . Wherein, if the first network device deduces K _gNB5 , the second network device can use the K _{gNB5 to} deduce the key K_RRCint ₅ , the key K_RRCenc ₅ , the key K_UPenc ₅ and the key K_UPint ₅ again. The context recovery response message may carry the corresponding key, the second NCC and the context of the terminal device, so that the second network device can communicate with the terminal device according to the corresponding key, the second NCC and the context of the terminal device. In addition, if the first network device stores the fourth data of the terminal device, after the verification is passed, the first network device can send the fourth data to the second network device, so that the second network device can forward the fourth data to the terminal device. data. The fourth data may be service data of the terminal device received by the first network device from a core network element, such as a UPF network element, and may be the same or different data from the above-mentioned first data.

Further, if the second network device receives the context recovery response message from the third network device, it can send a path switching request message to the AMF network element according to the context of the terminal device in the context recovery response message. In this way, the AMF network element can modify the bearer on the UPF network element according to the path switching request message. For example, the bearer is changed from "terminal device→first network device→UPF network element" to "terminal device→second network device" →UPF network element", so that the second network device can receive the fourth data from the terminal device of the core network and forward it to the terminal device. Then, the AMF network element may send a path switching request confirmation message to the second network device to inform the second network device that the path switching is completed. Wherein, since the second network device obtains the context of the terminal device, it can be considered that the anchor network device of the terminal device is changed from the first network device to the second network device.

Further, if the second network device receives the path switching request confirmation message from the AMF network element, it can send the terminal device context release message to the first network device, so that the first network device releases the context of the terminal device and the second I- RNTI to save resources and reduce overhead. In addition, if the second network device receives the above-mentioned third data, the second network device may send the third data to the UPF network element after receiving the confirmation of the path switching request.

It should be noted that the content in step 4 is introduced by taking the inter-site cell reselection as an example, that is, the first network device and the second network device are different network devices, but this is not a limitation. For example, if the terminal device performs cell reselection in the station of the first network device, the first network device may receive the above-mentioned second RRC message from the terminal device, and use the above-mentioned key and the pre-stored context of the terminal device and the terminal device Normal communication without requesting the context of the end device from other network devices.

Optionally, in the second implementation scenario of the embodiment shown in FIG. 4 , after step 4, the method may further include: step 5, the second network device sends a third RRC message to the terminal device, and the terminal device receives the third RRC message. A third RRC message from the second network device.

Wherein, the third RRC message may be an RRC release message, which is used to indicate the end of data transmission or the connection state has been restored, and also used to indicate which pair of I-RNTI and NCC the terminal device uses.

Specifically, the third RRC message may include: the third I-RNTI and the third NCC. Both the third I-RNTI and the third NCC may be allocated by the second network device to the terminal device. Wherein, if the third I-RNTI is the same as the second I-RNTI, the terminal device may be instructed to use the second I-RNTI; or, if the third I-RNTI is different from the second I-RNTI, the terminal device may be instructed to use the second I-RNTI Third I-RNTI. Wherein, if the third NCC is the same as the second NCC, the terminal device may be instructed to use the second NCC; or, if the third NCC is different from the second NCC, the terminal device may be instructed to use the third NCC. In this way, the terminal device can be flexibly instructed to update or continue to use the original I-RNTI and/or NCC according to the actual application scenario. For example, if communication security needs to be guaranteed, the terminal device is instructed to use the updated I-RNTI and NCC. For another example, if the resource overhead needs to be reduced, the terminal device is instructed to use the original I-RNTI and NCC to avoid the resource overhead caused by updating the I-RNTI and/or NCC.

Optionally, in the third implementation scenario of the embodiment shown in FIG. 4 , the method may further include: Step 6, the terminal device sends a packet data convergence protocol (packet data convergence protocol, PDCP) to the second network device. Status report, the second network device receives the PDCP status report from the terminal device.

Wherein, the PDCP status report records data that the terminal device has not received. The terminal device can package and send the RRC message, such as the second RRC message, with the PDCP status report, thereby reducing signaling overhead and further improving communication efficiency. Alternatively, the terminal device can also send the PDCP status report to the second network device independently, so as to realize more flexible sending.

Further, according to the above-mentioned first and second implementation scenarios, it can be known that in different implementation scenarios, the data received by the terminal device corresponds to different. Therefore, the following describes how the second network device processes the PDCP status report in combination with the first and second implementation scenarios described above.

In combination with the above-mentioned first implementation scenario, after receiving the PDCP status report from the terminal device, the second network device may forward the PDCP status report to the third network device. For example, the second network device may send a context recovery request message including the PDCP status report to the third network device, or may send an address indication message including the PDCP status report to the third network device to implement signaling multiplexing , further reducing resource overhead and further improving communication efficiency. In addition, the second network device may also send the PDCP status report to the third network device independently, so as to realize more flexible sending.

In a possible implementation manner, after receiving the PDCP status report from the second network device, the third network device may continue to forward the PDCP status report to the first network device, so that the first network device can, according to the PDCP status report, For example, according to the FMC field and the bitmap (Bitmap) field in the PDCP status report, the data that is not received by the terminal device in the first data is sent to the second network device or the third network device.

Further, if the first network device sends the unreceived data to the second network device, the second network device may directly forward the unreceived data to the terminal device. If the first network device sends the unreceived data to the third network device, the third network device may first forward the unreceived data to the second network device, so that the second network device can then forward the unreceived data to the terminal device data.

In another possible implementation manner, after receiving the PDCP status report from the second network device, the third network device may save the PDCP status report, so that the third network device can save the PDCP status report after receiving the first network device from the first network device. After the data is received, the unreceived data can be directly sent to the terminal device according to the PDCP status report.

In combination with the second implementation scenario above, after receiving the PDCP status report, the second network device may send, according to the PDCP status report, data that is not received by the terminal device in the fourth data to the terminal device. The above-mentioned fourth data may be data obtained by the second network device from the first network device and/or from the core network.

The principle of the communication method provided by the present application has been introduced above with reference to FIG. 4 , and the application of the method in practical scenarios will be described in detail below with reference to FIG. 5 and FIG. 6 .

Please refer to FIG. 5 , which shows a schematic flowchart of a communication method in a first application scenario. In FIG. 5 , the UE is the above-mentioned terminal equipment, the first gNB is the above-mentioned first network equipment, the second gNB is the above-mentioned second network equipment, and the second gNB is the above-mentioned third network equipment. In addition, as shown in FIG. 5 , the equipment suitable for the first application scenario may also include one or more of the following: a UPF network element, an AMF network element, and a policy control function (PCF) network element (Fig. 5), a session management function (SMF) network element (not shown in Figure 5), a unified data repository (unified data repository, UDR) network element (not shown in Figure 5), Unified data management (unified data management, UDM) network element (not shown in FIG. 5 ), etc. The AMF network element may also be correspondingly replaced with a mobility management entity (mobility management entity, MME) network element and the UPF network element may also be correspondingly replaced with a serving gateway (serving gateway, S-GW) network element, which is not limited.

As shown in FIG. 5 , in the first application scenario, the communication method may include:

S501, the third gNB sends a first RRC release message to the UE, and the third gNB receives the first RRC release message from the UE.

The first RRC release message may carry the above-mentioned first I-RNTI and the first NCC, and the third gNB is the anchor network device of the terminal device.

S502, the UE is released from the connected state to the inactive state.

Wherein, after the UE is released to the inactive state, the UE can retain its own context and key K_RRCint1.

S503, the UE reselects from the cell of the third gNB to the cell of the first gNB.

The UE remains in the inactive state after reselecting to the cell of the first gNB.

S504, the UE sends a first RRC recovery request message to the first gNB, and the first gNB receives the first RRC recovery request message from the UE.

The first RRC recovery request message may carry the first I-RNTI and the third truncated MAC-I. The third truncated MAC-I may be determined by the UE according to the cell configuration parameters of the third gNB and the key K_RRCint1.

S505, the UE determines the key K_RRCint2.

S506, the first gNB sends a first context recovery request message to the third gNB, and the third gNB receives the first context recovery request message from the first gNB.

The first context recovery request message may carry the first I-RNTI, the third truncated MAC-I, and the PCI of the cell of the first gNB. The execution order of S505 and S506 is not limited.

S507, the third gNB determines the key corresponding to the UE.

The specific implementation of determining the corresponding key by the third gNB may refer to the relevant content in the above S401, which will not be repeated here.

S508, the third gNB sends a first context recovery response message to the first gNB, and the first gNB receives the first context recovery response message from the third gNB.

The first context recovery response message may carry the context of the UE and the key determined in S507.

S509, the first gNB sends a first address indication message to the third gNB, and the third gNB receives the first address indication message from the first gNB.

S510, the third gNB sends the first downlink data to the first gNB, and the first gNB receives the first downlink data from the third gNB.

S511, the first gNB sends the first downlink data to the UE.

Among them, S510-S511 are optional steps. If the third gNB obtains the first downlink data in advance, such as receiving the first downlink data from the core network in advance, S510-S511 may be performed, otherwise, S510-S511 may not be performed.

S512, the first gNB sends a first path switching request message to the AMF network element.

S513, the AMF network element modifies the bearer of the UE on the UPF network element.

The bearer of the UE on the UPF network element may be changed from "UE→third gNB→UPF network element" to "UE→first gNB→UPF network element".

S514, the first gNB receives the first path switching request confirmation message sent from the AMF network element.

S515, the first gNB sends the first uplink data to the UPF network element.

Wherein, S515 is an optional step. If the UE multiplexes the first RRC recovery request message to send the first uplink data to the first gNB in S504, the first gNB can perform S515; otherwise, it is not necessary to perform S515.

S516, the first gNB receives the second downlink data from the UPF network element.

S517, the first gNB sends the second downlink data to the UE.

Among them, S516-S517 are optional steps. If the UPF network element receives the second downlink data from the core network, S516-S517 may be executed, otherwise, S516-S517 may not be executed. In addition, the execution order of S509-S511 and S512-S517 is not limited, and the execution order of S515 and S516 is also not limited.

It should be noted that, for the specific implementation of S501-S517, reference may be made to the relevant content in the foregoing S401, and for the specific implementation of S509, reference may also be made to the relevant content in the foregoing step 2, which will not be repeated here.

S518, the UE reselects from the cell of the first gNB to the cell of the second gNB.

The UE may remain in the inactive state after reselection to the cell of the second gNB according to the procedure predefined in the protocol. In addition, the execution order of S518 and S505-S517 is not limited. In addition, if the UE executes S518 after S511 and/or S517, the first gNB may execute S511 and/or S517; if the UE executes S518 before S511 and/or S517, because the UE is no longer in the first gNB A cell of a gNB camps on, so the first gNB cannot perform S511 and/or S517.

S519, the UE sends a second RRC recovery request message to the second gNB, and the second gNB receives the second RRC recovery request message from the UE.

The second RRC recovery request message may carry the first I-RNTI and the first truncated MAC-I. The first truncated MAC-I may be determined by the UE according to the cell configuration parameters of the first gNB and the key K_RRCint2.

S520, the UE sends a PDCP status report to the second gNB, and the second gNB receives the PDCP status report from the UE.

Wherein, S520 is an optional step. For example, if the amount of data needs to be reduced to ensure communication efficiency, S520 may be executed. For another example, if data loss needs to be avoided to ensure communication reliability, S520 may not be performed.

S521, the UE determines the key K_RRCint3.

S522, the second gNB sends a second context recovery request message to the third gNB, and the third gNB receives the second context recovery request message from the second gNB.

The second context recovery request message may carry the first I-RNTI, the first truncated MAC-I and the PCI of the cell of the second gNB. The execution order of S521 and S522 is not limited.

S523, the second gNB sends a PDCP status report to the third gNB, and the third gNB receives the PDCP status report from the second gNB.

Wherein, S523 is an optional step. According to the above S520, if the UE executes S520, the second gNB correspondingly executes S523; otherwise, the second gNB may not execute S523.

S524, the third gNB determines the key corresponding to the UE.

Wherein, for the specific implementation of determining the corresponding key by the third gNB, reference may be made to the relevant content in the foregoing step 1, and details are not repeated here.

S525, the third gNB sends a second context recovery response message to the second gNB, and the second gNB receives the second context recovery response message from the third gNB.

The second context recovery response message may carry the context of the UE and the key determined in S523.

S526, the second gNB sends the second address indication message to the third gNB, and the third gNB receives the second address indication message from the second gNB.

The second address indication message may carry the identifier of the UE, the above-mentioned first address and the above-mentioned second address.

It should be noted that the specific implementation of S519, S521, S522, S524 and S525 can refer to the above step 1, and the specific implementation of S520, S523 and S526 can refer to the relevant content in the above step 6, which will not be repeated here.

Further, according to the relevant content in the above step 6, it can be known that the first downlink data and the second downlink data on the first gNB can be sent by the first gNB to the second gNB, or can also be sent by the third gNB to the second gNB. The second gNB sends. They are introduced separately below.

On the one hand, the specific process for the first gNB to send downlink data to the second gNB may include the following S527-S529:

S527, the third gNB sends the second address indication message to the first gNB, and the second gNB receives the second address indication message from the third gNB.

S528, the third gNB sends a PDCP status report to the first gNB, and the first gNB receives the PDCP status report from the third gNB.

Wherein, S528 is an optional step. According to the above S523, if the second gNB executes S523, the third gNB correspondingly executes S528; otherwise, the third gNB may not execute S528.

S529, the first gNB sends the first downlink data and the second downlink data to the second gNB, or sends the third downlink data that is not received by the terminal device in the first downlink data and the second downlink data; the second gNB receives the The first downlink data and the second downlink data of the first gNB, or receive the third downlink data.

Wherein, if the first gNB obtains the PDCP status report, the first gNB can send the third downlink data to the second gNB; otherwise, the first gNB sends the first downlink data and the second downlink data to the second gNB.

For the specific implementation of S527-S529, reference may be made to the relevant content in the foregoing step 6, which will not be repeated here.

Wherein, the specific process of the third gNB sending downlink data to the second gNB may include the following S530-S533:

S530, the third gNB sends a third address indication message to the first gNB, and the first gNB receives the third address indication message from the third gNB.

The third address indication message may carry the identity of the UE and the address of the third gNB.

S531, the third gNB sends a PDCP status report to the first gNB, and the first gNB receives the PDCP status report from the third gNB.

Wherein, S531 is an optional step. For example, if the amount of data needs to be reduced to ensure communication efficiency, S531 may be executed. For another example, if data loss needs to be avoided to ensure communication reliability, S531 may not be performed.

S532, the first gNB sends the first downlink data and the second downlink data to the third gNB, or sends the third downlink data; the third gNB receives the first downlink data and the second downlink data from the first gNB, Or, the above-mentioned third downlink data is received.

Wherein, if the third gNB executes S531, the third gNB can directly receive the third downlink data; otherwise, the third gNB receives the first downlink data and the second downlink data.

S533, the third gNB sends the first downlink data and the second downlink data to the second gNB, or sends the third downlink data; the second gNB receives the first downlink data and the second downlink data from the third gNB, Or, the above-mentioned third downlink data is received.

Wherein, if the third gNB directly receives the above-mentioned third downlink data, or the third gNB saves the above-mentioned PDCP status report, the third gNB can send the above-mentioned third downlink data to the second gNB, otherwise, the third gNB sends the above-mentioned third downlink data to the second gNB. The gNB sends the above-mentioned first downlink data and second downlink data.

On the other hand, for the specific implementation of S530-S533, reference may be made to the relevant content in the foregoing step 6, and details are not repeated here.

S534, the second gNB sends the first downlink data and the second downlink data to the UE, or sends the third downlink data; the UE receives the first downlink data and the second downlink data from the second gNB, or receives the above-mentioned third downlink data; The third downstream data.

Wherein, if the UE executes S520, so that the second gNB obtains the PDCP status report, the second gNB can send the third downlink data to the UE, otherwise, the second gNB sends the first downlink data and the second downlink data to the UE .

S535, the second gNB sends a second path switching request message to the AMF network element.

S536, the AMF network element modifies the bearer of the UE on the UPF network element.

The bearer of the UE on the UPF network element may be modified from "UE→first gNB→UPF network element" to "UE→second gNB→UPF network element".

S537, the second gNB receives the second path switching request confirmation message sent from the AMF network element.

S538, the second gNB sends an RRC release message to the UE, and the UE receives the RRC release message from the second gNB.

The execution order of S534 and S535-S537 is not limited. For the specific implementation of S534, reference may be made to the relevant content in the foregoing step 6, and for the specific implementation of the S535-S538, reference may be made to the foregoing S401 and the relevant content in the step 5, which will not be repeated here.

Please refer to FIG. 6, which shows a schematic flowchart of the communication method in the second application scenario. In FIG. 6 , the UE is the above-mentioned terminal equipment, the first gNB is the above-mentioned first network equipment, the second gNB is the above-mentioned second network equipment, and the second gNB is the above-mentioned third network equipment. In addition, as shown in FIG. 6 , the equipment suitable for the first application scenario may also include one or more of the following: AMF network element, UPF network element, UPF network element, and AMF network element (not shown in FIG. 6 ) ), PCF network element (not shown in Figure 6), SMF network element (not shown in Figure 6), UDR network element (not shown in Figure 6), UDM network element (not shown in Figure 6), etc. .

Exemplarily, in the second application scenario, the flow of the communication method may include:

S601, the third gNB sends a first RRC release message to the UE, and the third gNB receives the first RRC release message from the UE.

S602, the UE is released from the connected state to the inactive state.

S603, the UE reselects from the cell of the third gNB to the cell of the first gNB.

S604, the UE sends a first RRC recovery request message to the first gNB, and the first gNB receives the first RRC recovery request message from the UE.

S605, the UE determines the key K_RRCint2.

S606, the first gNB sends the first context recovery request message to the third gNB, and the third gNB receives the first context recovery request message from the first gNB.

S607, the third gNB determines the key corresponding to the UE.

The first context recovery request message may carry the first I-RNTI, the third truncated MAC-I, and the PCI of the cell of the first gNB. In addition, the execution order of S605 and S606 is not limited. For the specific implementation of S601-S607, reference may be made to the relevant content in the above-mentioned S401, which will not be repeated here.

Further, according to the relevant content in the above step 3, it can be known that the above-mentioned first information can be generated in two ways, which can be generated by the third gNB, or can also be generated by the first gNB. They are introduced separately below.

On the one hand, the specific process of generating the above-mentioned first information by the first gNB may include the following S608-S609:

S608, the third gNB generates the above-mentioned first information.

The execution order of S607 and S608 is not limited.

S609, the third gNB sends a first context recovery response message to the first gNB, and the first gNB receives the first context recovery response message from the third gNB.

The first context recovery response message may carry the context of the UE, the first information determined in S608, and the key determined in S607. In addition, for the specific implementation of S608-S609, reference may be made to the relevant content in the foregoing step 3, which will not be repeated here.

On the one hand, the specific process of generating the above-mentioned first information by the second gNB may include the following S610-S611:

S610, the first gNB generates the above-mentioned first information.

The above-mentioned first information may include the second I-RNTI and the second NCC. The execution order of S610 and S607 is not limited.

S611, the third gNB sends a first context recovery response message to the first gNB, and the first gNB receives the first context recovery response message from the third gNB.

The first context recovery response message may carry the context of the UE and the key determined in S607. In addition, for the specific implementation of S610-S611, reference may be made to the relevant content in the foregoing step 3, which will not be repeated here.

S612, the first gNB sends a first RRC release message to the UE.

The first RRC release message may carry the first information. For the specific implementation of S612, reference may be made to the relevant content in the foregoing step 3, which will not be repeated here.

S613, the first gNB sends the first address indication message to the third gNB, and the third gNB receives the first address indication message from the first gNB.

S614, the third gNB sends the first downlink data to the first gNB, and the first gNB receives the first downlink data from the third gNB.

Wherein, S614 is an optional step. If the third gNB obtains the first downlink data in advance, such as receiving the first downlink data from the core network in advance, S614 may be performed, otherwise, S614 may not be performed.

S615, the first gNB sends a first path switching request message to the AMF network element.

S616, the AMF network element modifies the bearer of the UE on the UPF network element.

S617, the first gNB receives the first path switching request confirmation message sent from the AMF network element.

S618, the first gNB sends a second RRC release message to the third gNB, and the third gNB receives the second RRC release message from the first gNB.

S619, the first gNB receives the second downlink data from the UPF network element.

The execution order of S612 and S613-S619 is not limited, and the execution order of S613-S614 and S615-S619 is also not limited.

S620, the first gNB sends the first uplink data to the UPF network element.

The execution order of S619 and S620 is not limited. S619 is an optional step. If the UPF network element receives the second downlink data from the core network, S619 may be executed, otherwise, S619 may not be executed. S620 is also an optional step. If the UE multiplexes the first RRC recovery request message in S604 to send the first uplink data to the first gNB, the first gNB can perform S620; otherwise, it is unnecessary to perform S620. In addition, for the specific implementation of S613-S620, reference may be made to the relevant content in the above-mentioned S401, which will not be repeated here.

S621, the UE reselects from the cell of the first gNB to the cell of the second gNB.

The UE may, according to the indication of the first information, remain in the inactive state after reselecting to the cell of the second gNB.

S622, the UE sends a second RRC recovery request message to the second gNB, and the second gNB receives the second RRC recovery request message from the UE.

The second RRC recovery request message may carry the above-mentioned second I-RNTI and the second truncated MAC-I. The second truncated MAC-I may be determined by the UE according to the cell configuration parameters of the second gNB and the key K_RRCint4.

S623, the UE sends a PDCP status report to the second gNB, and the second gNB receives the PDCP status report from the UE.

Wherein, S623 is an optional step. For example, if the amount of data needs to be reduced to ensure communication efficiency, S623 may be executed. For another example, if data loss needs to be avoided to ensure communication reliability, S623 may not be performed.

S624, the UE determines the key K_RRCint5.

S625, the second gNB sends a second context recovery request message to the first gNB, and the first gNB receives the second context recovery request message from the second gNB.

The second context recovery request message may carry the second I-RNTI, the second truncated MAC-I, and the PCI of the cell of the second gNB. The execution order of S624 and S625 is not limited.

S626, the second gNB sends a PDCP status report to the first gNB, and the first gNB receives the PDCP status report from the second gNB.

Among them, S626 is an optional step. According to the above S623, if the UE executes S623, the second gNB correspondingly executes S626; otherwise, the second gNB may not execute S626.

S627, the first gNB determines the key corresponding to the UE.

Wherein, for the specific implementation of determining the corresponding key by the first gNB, reference may be made to the relevant content in the foregoing step 4, and details are not described herein again.

S628, the first gNB sends a second context recovery response message to the second gNB, and the second gNB receives the second context recovery response message from the first gNB.

The second context recovery response message may carry the context of the UE and the key determined in S627.

S629, the second gNB sends a second address indication message to the first gNB, and the first gNB receives the first address indication message from the second gNB.

S630, the first gNB sends the first downlink data and/or the second downlink data to the second gNB, or sends the third downlink data in the first downlink data and the second downlink data that is not received by the terminal device; the first gNB Receive the first downlink data and the second downlink data from the second NB, or receive the third downlink data.

S631, the second gNB sends the first downlink data and the second downlink data to the UE, or sends the third downlink data; the UE receives the first downlink data and the second downlink data from the second NB, or receives the first downlink data and the second downlink data from the second NB. Three downlink data.

Among them, S630-S631 are optional steps. If S614 and/or S619 are executed as described above, then S630-S631 may continue to be executed, otherwise, S630-S631 may not be executed. In addition, the specific implementation of S623, S626, and S629-S631 can refer to the relevant content in the above-mentioned step 6, and the specific implementation of S622, S624, S625, S627, and S628 can refer to the relevant content in the above-mentioned step 4, which is not repeated here. Repeat.

S632, the second gNB sends a second path switching request message to the AMF network element.

S633, the AMF network element modifies the bearer of the UE on the UPF network element.

S634, the second gNB receives the second path switching request confirmation message sent from the AMF network element.

S635, the second gNB sends a second RRC release message to the first gNB, and the first gNB receives the second RRC release message from the second gNB.

S636, the second gNB sends a third RRC release message to the UE, and the UE receives the second RRC release message from the third gNB.

The execution order of S629-S631 and S632-S635 is not limited. For the specific implementation of S632-S635, reference may be made to the relevant content in the foregoing step 4, and for the specific implementation of S636, reference may be made to the relevant content in the foregoing step 5, which will not be repeated here.

Based on the communication method shown in any one of FIG. 4 to FIG. 6 , since the terminal device performs cell reselection after sending the first RRC message to the first network device, it can still remain in the inactive state, so that the terminal device is in the cell After reselection, data can still be directly transmitted in the inactive state, so as to improve the efficiency and reliability of data transmission.

The communication method provided by the embodiment of the present application has been described in detail above with reference to FIG. 4 to FIG. 6 . A communication apparatus for executing the communication method provided by the embodiments of the present application will be described in detail below with reference to FIGS. 7 to 8 .

Exemplarily, FIG. 7 is a first structural schematic diagram of a communication apparatus provided by an embodiment of the present application. As shown in FIG. 7 , the communication apparatus 700 may include: a processing module 701 and a transceiver module 702 . For the convenience of description, FIG. 7 only shows the main components of the communication device 700 .

Exemplarily, the communication apparatus 700 can be applied to the communication system shown in FIG. 2 to perform the functions of the terminal device in the communication method shown in FIG. 4 , or to perform the functions shown in FIGS. 5-6 . The function of the UE in the communication method.

The transceiver module 702 is configured to send the first radio resource control RRC message to the first network device. The processing module 701 is used for the communication apparatus to perform reselection from the cell of the first network device to the cell of the second network device. Wherein, the communication device remains in an inactive state.

In a possible design solution, the transceiver module 702 is further configured to send the second RRC message to the second network device. Wherein, the second RRC message may include: the first I-RNTI. The first I-RNTI may be allocated by the third network device to the communication apparatus. The third network device may be an anchor network device of the communication apparatus. Wherein, the second RRC message may further include: the first truncated MAC-I. The first truncated MAC-I may be determined according to a cell configuration parameter of the third network device and the first key. The first key may be determined according to the first NCC. The first NCC is allocated to the communication apparatus by the third network device.

In another possible design solution, before the processing module 701 performs cell reselection, the transceiver module 702 is further configured to receive the first information from the first network device. Wherein, the first information may include: the second I-RNTI and the second NCC. The second I-RNTI may be allocated by the first network device or the third network device for the communication apparatus. The second NCC may be allocated to the communication apparatus by the first network device or the third network device. The third network device may be an anchor network device of the communication apparatus.

Optionally, the transceiver module 702 is further configured to send the second RRC message to the second network device. The second RRC message may carry the second I-RNTI and the second truncated MAC-I. The second truncated MAC-I may be determined according to a cell configuration parameter of the first network device and the second key. The second key may be determined according to the second NCC.

Optionally, the transceiver module 702 is further configured to receive a third RRC message from the second network device. Wherein, the third RRC message may include: the third I-RNTI and the third NCC. The third I-RNTI and the third NCC may be allocated by the second network device for the communication apparatus. The third I-RNTI may be different from the second I-RNTI, and/or the third NCC may be different from the second NCC; alternatively, the third RRC message instructs the communication apparatus to use the second I-RNTI and the second NCC.

In a possible design solution, the transceiver module 702 is further configured to send a PDCP status report to the second network device.

Optionally, the transceiver module 702 may include a receiving module and a transmitting module (not shown in FIG. 7 ). The receiving module is used to implement the receiving function of the communication device 700 , and the transmitting module is used to implement the transmitting function of the communication device 700 .

Optionally, the communication apparatus 700 may further include a storage module (not shown in FIG. 7 ), where the storage module stores programs or instructions. When the processing module 701 executes the program or instruction, the communication apparatus 700 can perform the function of the terminal device in the communication method shown in FIG. 4 and the function of the UE in the communication method shown in FIG. 5 to FIG. 6 .

It should be understood that the processing module 701 involved in the communication device 700 may be implemented by a processor or a processor-related circuit component, and may be a processor or a processing unit; the transceiver module 702 may be implemented by a transceiver or a transceiver-related circuit component, and may be a transceiver module Receiver or Transceiver Unit.

It should be noted that the communication device 700 may be a terminal device, a chip (system) or other components or components that can be provided in the terminal device, or a device including a terminal device, which is not limited in this application.

In addition, for the technical effect of the communication apparatus 700, reference may be made to the technical effect of the communication method shown in any one of FIG. 4 to FIG. 6 , which will not be repeated here.

Exemplarily, FIG. 8 is a second schematic structural diagram of a communication apparatus provided by an embodiment of the present application. As shown in FIG. 8 , the communication apparatus 800 may include: a receiving module 801 and a sending module 802 . For the convenience of description, FIG. 8 only shows the main components of the communication device 800 .

In some embodiments, the communication apparatus 800 may be applied to the communication system shown in FIG. 2 to perform the function of the first network device in the communication method shown in FIG. The function of gNB1 in the communication method shown.

The receiving module 801 is configured to receive the first RRC message from the terminal device. Wherein, if the terminal device performs cell reselection after sending the RRC message, the terminal device remains in an inactive state.

In a possible design solution, the terminal device is reselected from the cell of the communication apparatus to the cell of the second network device, and the sending module 802 is configured to send the first data of the terminal device to the second network device.

In another possible design solution, the terminal device is reselected from the cell of the communication apparatus to the cell of the second network device, and the sending module 802 is configured to send the first data of the terminal device to the third network device. The third network device may be an anchor network device of the terminal device.

In a possible design solution, the sending module 802 is configured to send the first information to the terminal device. Wherein, the first information may include: the second I-RNTI and the second NCC. The second I-RNTI may be allocated to the terminal device by the communication apparatus or the third network device. The second NCC may be allocated to the terminal device by the communication apparatus or the third network device. The third network device may be an anchor network device of the terminal device.

Optionally, before the sending module 802 sends the first information to the terminal device, the sending module 802 is further configured to send a context recovery request message to the third network device, and the sending module 801 is further configured to receive a message from the third network device. Context recovery response message. The third network device may be an anchor network device of the terminal device. The context restoration response message may include the first information.

In a possible design solution, the receiving module 801 is further configured to receive the PDCP status report from the terminal device.

Optionally, the receiving module 801 and the sending module 802 may also be integrated into one module, such as a transceiver module (not shown in FIG. 8 ). The transceiver module is used to implement the sending function and the receiving function of the communication device 800 .

Optionally, the communication apparatus 800 may further include a processing module 803 (shown with a dashed box in FIG. 8 ). The processing module 803 is used to implement the processing function of the communication device 800 .

Optionally, the communication apparatus 800 may further include a storage module (not shown in FIG. 8 ), where the storage module stores programs or instructions. When the receiving module 801 executes the program or instruction, the communication apparatus 800 can perform the function of the first network device in the communication method shown in FIG. 4 and the function of gNB1 in the communication method shown in FIG. 5-FIG. 6 . .

It should be understood that the processing module 803 involved in the communication apparatus 800 may be implemented by a processor or a processor-related circuit component, and may be a processor or a processing unit; the transceiver module may be implemented by a transceiver or a transceiver-related circuit component, and may be a transceiver or transceiver unit.

It should be noted that the communication device 800 may be a network device, a chip (system) or other components or components that can be provided in the network device, or a device including a network device, which is not limited in this application.

In addition, for the technical effect of the communication apparatus 800, reference may be made to the technical effect of the communication method shown in any one of FIG. 4 to FIG. 6 , which will not be repeated here.

In other embodiments, the communication apparatus 800 may be applied to the communication system shown in FIG. 2 to perform the function of the second network device in the communication method shown in FIG. 4 , or to perform the functions of the second network device in the communication method shown in FIG. The functions of gNB2 in the communication method shown.

The sending module 802 is configured to send the second information to the third network device. The receiving module 801 is configured to receive the first data from the first network device, so that the sending module 802 sends the first data to the terminal device. Wherein, the second information is used to request the first data of the terminal device. The third network device may be an anchor network device of the terminal device. The first network device may be a device corresponding to a cell in which the terminal device reselection to the cell of the communication apparatus resides before.

In a possible design solution, the receiving module 801 is further configured to receive the second RRC message from the terminal device. Wherein, the second RRC message may include: the first I-RNTI. The first I-RNTI may be allocated by the third network device to the terminal device. And, the second RRC message may further include: the first truncated MAC-I. The first truncated MAC-I may be determined according to a cell configuration parameter of the third network device and a first key, and the first key may be determined according to the first NCC. The first NCC may be allocated by the third network device to the terminal device. Alternatively, the second RRC message may include: the second I-RNTI. The second I-RNTI may be allocated by the first network device or the third network device for the terminal device. And, the second RRC message may further include: a second truncated MAC-I. The second truncated MAC-I may be determined according to a cell configuration parameter of the first network device and a second key, and the second key may be determined according to the second NCC. The second NCC may be allocated to the terminal device by the first network device or by the third network device. The third network device may be an anchor network device of the terminal device.

In a possible design solution, the receiving module 801 is further configured to receive the PDCP status report from the terminal device. The sending module is further configured to send the PDCP status report to the third network device, so that the third network device can send data that the terminal device has not received to the terminal device according to the PDCP status report.

Optionally, the sending module 802 is further configured to send a context recovery request message to the third network device. Wherein, the context recovery request message may include a PDCP status report.

Optionally, the communication apparatus 800 may further include a storage module (not shown in FIG. 8 ), where the storage module stores programs or instructions. When the receiving module 801 executes the program or instruction, the communication apparatus 800 can perform the function of the second network device in the communication method shown in FIG. 4 and the function of gNB2 in the communication method shown in FIG. 5-FIG. 6 .

Exemplarily, FIG. 9 is a schematic structural diagram of a communication apparatus provided by an embodiment of the present application. The communication device may be a terminal device or a network device, or may be a chip (system) or other components or assemblies that can be provided in the terminal device or the network device. As shown in FIG. 9 , the communication apparatus 900 may include a processor 901 . Optionally, the communication device 900 may further include a memory 902 and/or a transceiver 903 . Wherein, the processor 901 is coupled with the memory 902 and the transceiver 903, such as can be connected through a communication bus.

Each component of the communication device 900 will be described in detail below with reference to FIG. 9 :

The processor 901 is the control center of the communication device 900, which may be one processor or a general term for multiple processing elements. For example, the processor 901 is one or more central processing units (central processing units, CPUs), may also be a specific integrated circuit (application specific integrated circuit, ASIC), or is configured to implement one or more of the embodiments of the present application An integrated circuit, such as: one or more microprocessors (digital signal processor, DSP), or, one or more field programmable gate array (field programmable gate array, FPGA).

Optionally, the processor 901 may execute various functions of the communication device 900 by running or executing software programs stored in the memory 902 and calling data stored in the memory 902 .

In a specific implementation, as an embodiment, the processor 901 may include one or more CPUs, such as CPU0 and CPU1 shown in FIG. 9 .

In a specific implementation, as an embodiment, the communication apparatus 900 may also include multiple processors, for example, the processor 901 and the processor 904 shown in FIG. 9 . Each of these processors can be a single-core processor (single-CPU) or a multi-core processor (multi-CPU). A processor herein may refer to one or more devices, circuits, and/or processing cores for processing data (eg, computer program instructions).

The memory 902 is used to store the software program for executing the solution of the present application, and is controlled and executed by the processor 901. For the specific implementation, reference may be made to the above method embodiments, which will not be repeated here.

Alternatively, memory 902 may be read-only memory (ROM) or other types of static storage devices that can store static information and instructions, random access memory (RAM), or other types of static storage devices that can store information and instructions. Other types of dynamic storage devices for instructions, which may also be electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM), or other optical disks storage, optical disc storage (including compact disc, laser disc, optical disc, digital versatile disc, blu-ray disc, etc.), magnetic disk storage medium or other magnetic storage device, or capable of carrying or storing desired program code in the form of instructions or data structures and any other medium that can be accessed by a computer, but is not limited thereto. The memory 902 may be integrated with the processor 901, or may exist independently, and be coupled to the processor 901 through an interface circuit (not shown in FIG. 9) of the communication device 900, which is not specifically limited in this embodiment of the present application.

The transceiver 903 is used for communication with other communication devices. For example, the communication apparatus 900 is a terminal device, and the transceiver 903 may be used to communicate with a network device or communicate with another terminal device. For another example, the data communication apparatus 900 is a network device, and the transceiver 903 can be used to communicate with a terminal device or communicate with another network device.

Optionally, transceiver 903 may include a receiver and a transmitter (not shown separately in FIG. 9). Among them, the receiver is used to realize the receiving function, and the transmitter is used to realize the sending function.

Optionally, the transceiver 903 may be integrated with the processor 901, or may exist independently, and be coupled to the processor 901 through an interface circuit (not shown in FIG. 9 ) of the communication device 900, which is not made in this embodiment of the present application Specific restrictions.

It should be noted that the structure of the communication device 900 shown in FIG. 9 does not constitute a limitation on the communication device, and an actual communication device may include more or less components than those shown in the figure, or combine some components, or Different component arrangements.

In addition, for the technical effect of the communication apparatus 900, reference may be made to the technical effect of the communication method described in the above method embodiments, which will not be repeated here.

An embodiment of the present application further provides a chip system, which may include: a processor, where the processor is coupled with a memory, and the memory is used for storing a program or an instruction, and when the program or instruction is executed by the processor, the processor causes the The chip system implements the method in any of the above method embodiments.

Optionally, the number of processors in the chip system may be one or more. The processor can be implemented by hardware or by software. When implemented in hardware, the processor may be a logic circuit, an integrated circuit, or the like. When implemented in software, the processor may be a general-purpose processor implemented by reading software codes stored in memory.

Optionally, there may also be one or more memories in the chip system. The memory may be integrated with the processor, or may be provided separately from the processor, which is not limited in this application. Exemplarily, the memory can be a non-transitory processor, such as a read-only memory ROM, which can be integrated with the processor on the same chip, or can be provided on different chips. The setting method of the processor is not particularly limited.

Exemplarily, the system-on-chip may be a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or a system on chip (SoC), It can also be a central processing unit (CPU), a network processor (NP), a digital signal processing circuit (DSP), or a microcontroller (microcontroller). controller unit, MCU), it can also be a programmable logic device (PLD) or other integrated chips.

Embodiments of the present application provide a communication system. The communication system may include one or more terminal devices described above, and one or more network devices.

It should be understood that the processor in this embodiment of the present application may be a central processing unit (central processing unit, CPU), and the processor may also be other general-purpose processors, digital signal processors (digital signal processors, DSP), special integrated Circuit (application specific integrated circuit, ASIC), off-the-shelf programmable gate array (field programmable gate array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

It should also be understood that the memory in the embodiments of the present application may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically programmable Erase programmable read-only memory (electrically EPROM, EEPROM) or flash memory. Volatile memory may be random access memory (RAM), which acts as an external cache. By way of example and not limitation, many forms of random access memory (RAM) are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (DRAM) Access memory (synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (double data rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (enhanced SDRAM, ESDRAM), synchronous connection dynamic random access memory Fetch memory (synchlink DRAM, SLDRAM) and direct memory bus random access memory (direct rambus RAM, DR RAM).

The above embodiments may be implemented in whole or in part by software, hardware (eg, circuits), firmware, or any other combination. When implemented in software, the above-described embodiments may be implemented in whole or in part in the form of a computer program product. The computer program product may comprise one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer may be a general purpose computer, special purpose computer, computer network, or other programmable device. The computer instructions may be stored in or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be downloaded from a website site, computer, server, or data center Transmission to another website site, computer, server or data center by wire (eg, infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, a data center, or the like that contains one or more sets of available media. The usable media may be magnetic media (eg, floppy disks, hard disks, magnetic tapes), optical media (eg, DVDs), or semiconductor media. The semiconductor medium may be a solid state drive.

It should be understood that the term "and/or" in this document is only an association relationship to describe associated objects, indicating that there can be three kinds of relationships, for example, A and/or B, which can mean that A exists alone, and A and B exist at the same time , there are three cases of B alone, where A and B can be singular or plural. In addition, the character "/" in this document generally indicates that the related objects before and after are an "or" relationship, but may also indicate an "and/or" relationship, which can be understood with reference to the context.

In this application, "at least one" means one or more, and "plurality" means two or more. "At least one item(s) below" or its similar expressions refers to any combination of these items, which may include any combination of single item(s) or plural items(s). For example, at least one item (a) of a, b, or c can represent: a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, c may be single or multiple .

It should be understood that, in various embodiments of the present application, the size of the sequence numbers of the above-mentioned processes does not mean the sequence of execution, and the execution sequence of each process should be determined by its functions and internal logic, and should not be dealt with in the embodiments of the present application. implementation constitutes any limitation.

Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of this application.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described systems, devices and units may refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not implemented. On the other hand, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as independent products, may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be embodied in the form of a software product in essence, or the part that contributes to the prior art or the part of the technical solution. The computer software product is stored in a storage medium, which can Several instructions are included to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium may include: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk or CD, etc. that can store program codes. medium.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited to this. should be covered within the scope of protection of this application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

A communication method, wherein the method is applied to a terminal device or a chip in the terminal device, comprising:

sending a first radio resource control RRC message to the first network device;

Reselection from the cell of the first network device to the cell of the second network device, wherein the terminal device remains in an inactive state.
The method according to claim 1, wherein the method further comprises:

sending a second RRC message to the second network device;

The second RRC message includes: a first inactive wireless network temporary identifier I-RNTI, the first I-RNTI is allocated by a third network device for the terminal device, and the third network device is the anchor network device of the terminal device;

The second RRC message further includes: a first truncated integrity message authentication code MAC-I, where the first truncated MAC-I is based on the cell configuration parameters of the third network device and the first truncated MAC-I. The key is determined, the first key is determined by calculating the NCC according to the first next-hop chain, and the first NCC is allocated by the third network device to the terminal device.
The method according to claim 1, wherein the method further comprises:

before performing cell reselection, receiving first information from the first network device;

The first information includes: a second I-RNTI and a second NCC, the second I-RNTI is allocated by the first network device or the third network device for the terminal device, and the second The NCC is allocated by the first network device or the third network device for the terminal device, and the third network device is an anchor network device of the terminal device.
The method according to claim 3, wherein the method further comprises:

sending a second RRC message to the second network device;

The second RRC message carries the second I-RNTI and a second truncated MAC-I, and the second truncated MAC-I is based on the cell configuration parameters of the first network device and the first truncated MAC-I. The second key is determined according to the second NCC.
The method according to claim 3 or 4, wherein the method further comprises:

receiving a third RRC message from the second network device;

The third RRC message includes: a third I-RNTI and a third NCC, the third I-RNTI and the third NCC are allocated by the second network device for the terminal device, the The third I-RNTI is different from the second I-RNTI, and/or the third NCC is different from the second NCC; or,

The third RRC message instructs the terminal device to use the second I-RNTI and the second NCC.
The method according to any one of claims 1-5, wherein the method further comprises:

Send a Packet Data Convergence Protocol PDCP status report to the second network device.
A communication method, characterized in that the method is applied to a first network device or a chip in the first network device, and the method includes:

Receive the first RRC message from the terminal device, wherein if the terminal device performs cell reselection after sending the RRC message, the terminal device remains in an inactive state.
The method according to claim 7, wherein the terminal equipment is reselected from the cell of the first network device to the cell of the second network device, the method further comprising:

Send the first data of the terminal device to the second network device.
The method according to claim 7, wherein the terminal device is reselected from the cell of the first network device to the cell of the second network device, the method further comprising:

The first data of the terminal device is sent to a third network device, where the third network device is an anchor point network device of the terminal device.
The method according to claim 7, wherein the method further comprises:

Send first information to the terminal device, where the first information includes: a second I-RNTI and a second NCC, the second I-RNTI is the first network device or the third network device is the The second NCC is allocated by the first network device or the third network device is allocated for the terminal device, and the third network device is the anchor network device of the terminal device.
The method according to claim 10, wherein before the sending the first information to the terminal device, the method further comprises:

sending a context recovery request message to a third network device, where the third network device is: an anchor network device of the terminal device;

A context recovery response message is received from the third network device, wherein the context recovery response message includes the first information.
The method according to any one of claims 7-11, wherein the method further comprises:

A PDCP status report is received from the terminal device.
A communication device is characterized by comprising: a transceiver module and a processing module, wherein,

the transceiver module, configured to send the first radio resource control RRC message to the first network device;

The processing module is used for the communication apparatus to perform reselection from the cell of the first network equipment to the cell of the second network equipment, wherein the communication apparatus remains in an inactive state.
The device of claim 13, wherein:

The transceiver module is further configured to send a second RRC message to the second network device;

The second RRC message includes: a first I-RNTI, the first I-RNTI is allocated by a third network device for a terminal device, and the third network device is an anchor network device of the terminal device ;

Wherein, the second RRC message further includes: a first truncated MAC-I, where the first truncated MAC-I is determined according to the cell configuration parameter of the third network device and the first key, The first key is determined according to the first NCC, and the first NCC is allocated by the third network device to the terminal device.
The device of claim 13, wherein:

Before the processing module performs cell reselection, the transceiver module is further configured to receive first information from the first network device;

The first information includes: a second I-RNTI and a second NCC, the second I-RNTI is allocated by the first network device or the third network device for a terminal device, and the second NCC is The first network device or the third network device is allocated by the terminal device, and the third network device is an anchor network device of the terminal device.
The apparatus of claim 15, wherein:

The transceiver module is further configured to send a second RRC message to the second network device;

The second RRC message carries the second I-RNTI and a second truncated MAC-I, and the second truncated MAC-I is based on the cell configuration parameters of the first network device and the first truncated MAC-I. The second key is determined according to the second NCC.
The device according to claim 15 or 16, characterized in that,

The transceiver module is further configured to receive a third RRC message from the second network device;

The third RRC message includes: a third I-RNTI and a third NCC, the third I-RNTI and the third NCC are allocated by the second network device for the terminal device, the The third I-RNTI is different from the second I-RNTI, and/or the third NCC is different from the second NCC; or, the third RRC message instructs the terminal device to use the second NCC I-RNTI and the second NCC.
The device according to any one of claims 13-17, characterized in that,

The transceiver module is further configured to send a packet data convergence protocol PDCP status report to the second network device.
A communication device, comprising: a receiving module, wherein,

The receiving module is configured to receive the first RRC message from the terminal device, wherein if the terminal device performs cell reselection after sending the RRC message, the terminal device remains in an inactive state.
The apparatus according to claim 19, wherein the terminal equipment is reselected from the cell of the first network equipment to the cell of the second network equipment, the apparatus further comprising: a sending module, wherein:

The sending module is configured to send the first data of the terminal device to the second network device.
The apparatus according to claim 19, wherein the terminal equipment is reselected from the cell of the first network equipment to the cell of the second network equipment, the apparatus further comprising: a sending module, wherein:

The sending module is configured to send the first data of the terminal device to a third network device, wherein the third network device is an anchor network device of the terminal device.
The apparatus according to claim 19, wherein the apparatus further comprises: a sending module, wherein:

The sending module is configured to send first information to the terminal device, wherein the first information includes: a second I-RNTI and a second NCC, and the second I-RNTI is a first network device or a second NCC. Three network devices are allocated to the terminal device, the second NCC is allocated to the terminal device by the first network device or a third network device, and the third network device is the anchor network device of the terminal device .
The apparatus according to claim 22, wherein before the sending module sends the first information to the terminal device, the sending module is further configured to send a context recovery request message to a third network device, and, The receiving module is further configured to receive a context recovery response message from the third network device, wherein the third network device is an anchor network device of the terminal device, and the context recovery response message includes the first information.
The device according to any one of claims 19-23, characterized in that,

The receiving module is further configured to receive a PDCP status report from the terminal device.
A communication device, comprising: a module for executing the method according to any one of claims 1 to 6.
A communication device, comprising: a module for executing the method according to any one of claims 7 to 12.
A communication device, comprising: a processor and a memory, the processor and the memory are coupled, and the processor is configured to control the device to implement the method according to any one of claims 1 to 6 .
A communication device, comprising: a processor and a memory, the processor and the memory are coupled, and the processor is configured to control the device to implement the method according to any one of claims 7 to 12 .
A communication device, characterized by comprising: a processor and an interface circuit, the interface circuit is configured to receive signals from other communication devices other than the communication device and transmit to the processor or transfer signals from the processor The signal of the processor is sent to other communication devices other than the communication device, and the processor is used for implementing the method according to any one of claims 1 to 6 through logic circuits or executing code instructions.
A communication device, characterized by comprising: a processor and an interface circuit, the interface circuit is configured to receive signals from other communication devices other than the communication device and transmit to the processor or transfer signals from the processor The signal of the processor is sent to other communication devices than the communication device, and the processor is used for implementing the method as claimed in any one of claims 7 to 12 through logic circuits or executing code instructions.
A computer-readable storage medium, characterized in that, the computer-readable storage medium comprises: a computer program or instruction, when the computer program or instruction is executed on a computer, the computer is made to perform the execution of claims 1-12 The communication method described in any one of.
A computer program product, characterized in that the computer program product comprises: a computer program or instruction, when the computer program or instruction is run on a computer, the computer is made to execute any one of claims 1-12 the described communication method.