CN113747515B

CN113747515B - Communication method and device

Info

Publication number: CN113747515B
Application number: CN202010460755.5A
Authority: CN
Inventors: 王亚鑫; 李岩
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-05-27
Filing date: 2020-05-27
Publication date: 2023-03-21
Anticipated expiration: 2040-05-27
Also published as: WO2021238383A1; CN113747515A

Abstract

A communication method and device, the method includes: the CU-CP of the wireless access network equipment receives control port information from a core network element, when the terminal equipment is switched from a source DU of the wireless access network equipment to a target DU of the wireless access network equipment, the CU-CP acquires downlink tunnel information of the target DU for establishing first F1 user plane connection from the target DU, and the CU-CP sends the downlink tunnel information to the CU-UPF network element through a control port indicated by the control port information, so that the CU-UPF network element establishes the first F1 user plane connection according to the downlink tunnel information and the downlink tunnel information of the CU-UPF network element, and further the problems of service delay and high signaling cost caused by F1 user plane interface reconstruction are solved.

Description

Communication method and device

Technical Field

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

Background

In the third generation partnership project (3) ^rd generation partnership project,3 GPP) of the fifth generation mobile communication technology (the 5 ^th generation, 5G) New Radio (NR) system, a network architecture is proposed. Under the network architecture, the functions of the access network are divided into two units, a Centralized Unit (CU) and a Distributed Unit (DU). The functions of the CU are further divided into a control plane entity (CU-CP) and a user plane entity (CU-UP). Currently, one CU-CP and multiple CU-UP may be included in the entire access network.

Currently, a CU and a sinking User Plane Function (UPF) network element are usually deployed in the same physical machine room, and for the considerations of reducing data plane transmission hops, saving cost, setting data plane security nodes in a core network, and the like, it is very likely that the UPF network element and the CU-UP are combined into one network element, that is, the CU-UP is combined with the sinking UPF network element and is marked as the CU-UPF network element, and the CU-UPF network element is uniformly scheduled and managed by a Session Management Function (SMF) network element. Under the combined framework, when the access network device accessed by the terminal device is switched, the F1 user plane interface is rebuilt, the user plane context of the F1 interface needs to be regenerated because the F1 user plane interface is rebuilt, and the generation process of the user plane context of the F1 interface needs to involve in a core network element, so that the signaling flow is too long, and the time delay requirement of terminal switching cannot be met.

Disclosure of Invention

The application provides a communication method and a communication device, which are used for solving the problems of large service delay and large signaling overhead caused by F1 user interface reconstruction.

In a first aspect, an embodiment of the present application provides a communication method, where a scenario in which a terminal device is switched from a source DU of a RAN to a target DU of the RAN within a range served by a CU of the same RAN is provided, and a CU and the DU of the RAN in a network architecture to which the method is applied are separated, and a UPF network element and a CU-UP are combined to form one network element. The method may be performed by the CU-CP or an internal chip of the CU-CP, the method comprising: and the CU-CP receives control port information from the core network element, wherein the control port indicated by the control port information corresponds to the PDU session and is the control port of the CU-UPF network element. When the terminal equipment is switched from a source DU of the wireless access network equipment to a target DU of the wireless access network equipment, a CU-CP acquires downlink tunnel information of the target DU for establishing first F1 user plane connection from the target DU, and the CU-CP sends the downlink tunnel information to a CU-UPF network element through a control port indicated by the control port information, so that the CU-UPF network element establishes the first F1 user plane connection according to the downlink tunnel information and the downlink tunnel information of the CU-UPF network element, namely the downlink user plane connection between the target DU and the CU-UPF network element is established.

In the embodiment of the application, when a DU of a RAN accessed by a terminal device is switched, a CU-CP may communicate with a CU-UPF network element based on a control port acquired from a core network element in advance, and the CU-UPF network element may complete updating of a user plane context between a target DU accessed by the terminal device after switching and the CU-UPF network element based on downlink tunnel information of the target DU acquired by the control port from a CU-UP, so that the reconstruction of an F1 user plane interface between the target DU and the CU-UPF network element may be avoided, thereby reducing a switching delay, and improving problems of large service delay and large signaling overhead caused by the reconstruction of the F1 interface.

In one possible design, the method may further include: the CU-CP acquires the uplink tunnel information of the CU-UPF network element from the CU-UPF network element through the control port, the CU-CP sends the uplink tunnel information of the CU-UPF network element to the target DU, and the target DU establishes uplink user plane connection between the target DU and the CU-UPF network element according to the uplink tunnel information of the CU-UPF network element and the uplink tunnel information of the target DU, so that the target DU can receive uplink data from the terminal equipment through the uplink user plane connection.

In one possible implementation, the method may further include: and the CU-CP also sends verification information to the CU-UPF network element through the control port, the CU-UPF network element determines whether the CU-CP has the authority of acquiring the uplink tunnel information according to the verification information, when the CU-UPF network element determines that the CU-CP has the authority of acquiring the uplink tunnel information, the uplink tunnel information of the CU-UPF network element is sent to the CU-UPF network element, otherwise, the uplink tunnel information is not sent.

In a second aspect, an embodiment of the present application provides a communication method, where a scenario in which a terminal device is switched from a source DU of a RAN to a target DU of the RAN within a range served by a CU of the same RAN is provided. The method can be executed by a CU-UPF network element or an internal chip of the CU-UPF network element, and comprises the following steps: when the terminal equipment is switched from a source DU of the wireless access network equipment to a target DU of the wireless access network equipment, the CU-UPF network element receives a second message from a CU-CP of the wireless access network equipment through a control port, a control port indicated by the control port information corresponds to a PDU session and is the control port of the CU-UPF network element, and because the second message comprises the downlink tunnel information of the target DU, the CU-UPF network element establishes a first F1 user plane connection according to the downlink tunnel information and the downlink tunnel information of the CU-UPF network element.

In one possible design, the CU-UPF network element receives a request message from the CU-CP through the control port, because the request message is used to request uplink tunnel information of a second F1 user plane connection between the CU-UPF network element and the source DU; and the CU-UPF network element sends the uplink tunnel information to the CU-CP through the control port, wherein the uplink tunnel information is used for establishing uplink user plane connection between the target DU and the CU-UPF network element, so that the target DU receives uplink data from the terminal equipment through the uplink user plane connection.

In one possible design, the CU-UPF network element receives verification information from the CU-CP through the control port, the CU-UPF network element determines whether the CU-CP has the authority to acquire the uplink tunnel information according to the verification information, when the CU-UPF network element determines that the CU-CP has the authority to acquire the uplink tunnel information, the uplink tunnel information of the CU-UPF network element is sent to the CU-UPF network element, and otherwise, the uplink tunnel information is not sent.

In one possible design, the CU-UPF network element sends the downlink tunnel information of the target DU, and the uplink tunnel information and the downlink tunnel information of the CU-UPF network element to the core network element, so that the core network element updates the context information in time.

In a third aspect, an embodiment of the present application provides a communication method, where a scenario applicable to the method is that a terminal device switches from a source DU of a RAN to a target DU of the RAN within a range of a CU service of the same RAN, and a CU and the DU of the RAN in a network architecture applicable to the method are separated, and a UPF network element and a CU-UP network element are combined to form one network element. The method can be executed by a target DU network element or an internal chip of a target DU, and includes: a target DU of the wireless access network equipment receives first information from a core network element through a CU-CP of the wireless access network equipment, and when the terminal equipment is switched from a source DU of the wireless access network equipment to the target DU, the target DU sends a user plane data packet carrying downlink tunnel information of the target DU to the CU-UPF network element according to the first information, wherein the downlink tunnel information is used for establishing downlink user plane connection between the target DU and the CU-UPF network element.

In the embodiment of the application, when a DU of a RAN accessed by a terminal device is switched, a CU-CP may authorize a user plane data packet of a target DU to which the terminal device needs to switch to have a right to send control plane data, so that downlink tunnel information may be sent to a CU-UPF network element by using the user plane data packet, thereby completing updating of a user plane context between the target DU and the CU-UPF network element accessed after the terminal device is switched, which may avoid performing reconstruction of an F1 user plane context between the target DU and the CU-UPF network element, thereby reducing a switching delay, and improving problems of large service delay and large signaling overhead caused by reconstruction of an F1 interface.

In one possible design, the method may further include: the target DU acquires the uplink tunnel information of the CU-UPF network element from the CU-UPF network element through the CU-CP, and the target DU establishes uplink user plane connection between the target DU and the CU-UPF network element according to the uplink tunnel information of the CU-UPF network element and the uplink tunnel information of the target DU, so that the target DU can receive uplink data from the terminal equipment through the uplink user plane connection.

In one possible implementation, the method may further include: the target DU can also send verification information to the CU-UPF network element through the user plane data packet, the CU-UPF network element determines whether the target DU has the authority of acquiring the uplink tunnel information according to the verification information, when the CU-UPF network element determines that the target DU has the authority of acquiring the uplink tunnel information, the uplink tunnel information of the CU-UPF network element is sent to the target DU, otherwise, the uplink tunnel information is not sent.

In a fourth aspect, an embodiment of the present application provides a communication method, where a scenario in which a terminal device switches from a source DU of a RAN to a target DU of the RAN within a same RAN CU service range is provided, and a network architecture to which the method is applied includes that the CU and the DU of the RAN are separated, and a UPF network element and a CU-UP network element are combined to form one network element. The method may be performed by a CU-UPF network element or an internal chip of the CU-UPF network element, the method comprising: when the terminal equipment is switched from a source DU to a target DU of the wireless access network equipment, the CU-UPF network element receives a user plane data packet from the target DU, and because the user plane data packet carries downlink tunnel information of the target DU, the CU-UPF network element establishes a first F1 user plane connection according to the downlink tunnel information and the downlink tunnel information of the CU-UPF network element, namely the first F1 user plane connection is established as the downlink user plane connection between the target DU and the CU-UPF network element.

In one possible design, the method further includes: the CU-UPF network element also sends uplink tunnel information to the target DU through the CU-CP, and the target DU establishes uplink user plane connection between the target DU and the CU-UPF network element according to the uplink tunnel information of the CU-UPF network element and the uplink tunnel information of the target DU, so that the target DU receives uplink data from the terminal equipment through the uplink user plane connection.

In a fifth aspect, an embodiment of the present application provides a communication method, where a scenario in which a terminal device switches from a source DU of a source RAN to a target DU of a target RAN in different RAN services is provided, and a network architecture in which the method is applied is that a CU and the DU of the RAN are separated, and a UPF network element and a CU-UP are combined to form one network element. The method may be performed by the target CU-CP or an internal chip of the target CU-CP, the method comprising: a target control plane entity CU-CP of target wireless access network equipment receives control port information from a core network element through a source CU-CP of source wireless access network equipment, a control port indicated by the control port information corresponds to a protocol data unit PDU session and is a control port of a CU-UPF network element, and when terminal equipment is switched from a source DU of the source wireless access network equipment to a target DU of the target wireless access network equipment, the target CU-CP acquires downlink tunnel information of the target DU for establishing first F1 user plane connection from the target DU; wherein, the first F1 user interface connection is a downlink user interface connection between the target DU and the CU-UPF network element; and the target CU-CP sends the downlink tunnel information to the CU-UPF network element through the control port so as to facilitate the CU-UPF network element to establish the first F1 user plane connection.

In the embodiment of the application, when a terminal device switches from a source DU of a source RAN to a target DU of a target RAN within different RAN services, a target CU-CP of the target RAN may communicate with a CU-UPF network element based on a control port acquired from a core network element in advance, and the CU-UPF network element may acquire downlink tunnel information of the target DU from a target CU-UP based on the control port, thereby completing establishment of downlink user plane connection between the target DU and the CU-UPF network element accessed after the terminal device is switched, so that it is possible to avoid performing reconstruction of an F1 user plane interface between the target DU and the CU-UPF network element, thereby reducing switching delay, and improving problems of large service delay and large signaling overhead caused by reconstruction of the F1 interface.

In one possible implementation, the method may further include: the target CU-CP of the target RAN acquires uplink tunnel information of the CU-UPF network element from the CU-UPF network element through the control port, the target CU-CP sends the uplink tunnel information of the CU-UPF network element to the target DU, and the target DU establishes uplink user plane connection between the target DU and the CU-UPF network element according to the uplink tunnel information of the CU-UPF network element and the uplink tunnel information of the target DU, so that the target DU can receive uplink data from the terminal equipment through the uplink user plane connection.

In one possible implementation, the method may further include: and the target CU-CP also sends verification information to the CU-UPF network element through the control port, the CU-UPF network element determines whether the target CU-CP has the authority of acquiring the uplink tunnel information according to the verification information, when the CU-UPF network element determines that the target CU-CP has the authority of acquiring the uplink tunnel information, the uplink tunnel information of the CU-UPF network element is sent to the target CU-UPF network element, and otherwise, the uplink tunnel information is not sent.

In one possible implementation, the target CU-CP updates context information of the terminal device, and the target CU-CP sends the updated context information of the terminal device to a core network element, where the context information of the terminal device includes information of a target radio access network device serving the terminal device, so that the core network element updates the context information of the terminal device in time.

In a sixth aspect, an embodiment of the present application provides a communication method, where the method is applied to a scenario in which a terminal device switches from a source DU of a source RAN to a target DU of a target RAN in a range of different RAN services, and a CU and a DU of the RAN in a network architecture to which the method is applied are separated, and a UPF network element and a CU-UP network element are combined to form one network element. The method may be performed by a CU-UPF network element or an internal chip of the CU-UPF network element, the method comprising: when the terminal equipment is switched from a source DU of the source wireless access network equipment to a target DU of the target access network equipment, the CU-UPF network element receives a second message of a target CU-CP from the target wireless access network equipment through the control port; wherein, the second message includes the downlink tunnel information of the target DU, and the control port is the control port of the CU-UPF network element which is allocated by the core network element for the CU-UPF network element and corresponds to the protocol data unit PDU session; and the CU-UPF network element establishes the first F1 user plane connection according to the downlink tunnel information of the target DU and the downlink tunnel information of the CU _ UPF network element, namely, the downlink user plane connection between the target DU and the CU-UPF network element.

In one possible implementation, the method may further include: the CU-UPF network element also receives a request message from the CU-CP through the control port, wherein the request message is used for requesting uplink tunnel information, and the uplink tunnel information is the uplink tunnel information connected with a second F1 user plane between the CU-UPF network element and the source DU; the CU-UPF network element sends uplink tunnel information to the target CU-CP through the control port, wherein the uplink tunnel information is used for establishing uplink user plane connection between the target DU and the CU-UPF network element; so that the target DU receives uplink data from the terminal device via the uplink user plane connection.

In a seventh aspect, an embodiment of the present application provides a communication method, where a scenario in which a terminal device switches from a source DU of a source RAN to a target DU of a target RAN in different RAN services is provided, and a CU and a DU of the RAN in a network architecture to which the method is applied are separated, and a UPF network element and a CU-UP are combined to form one network element. The method can be executed by a target DU network element or an internal chip of a target DU, and comprises the following steps: a target DU of the target wireless access network equipment receives first information from a source CU-CP of the source wireless access network equipment through the target CU-CP of the target wireless access network equipment; when the terminal equipment is switched from a source DU of the source wireless access network equipment to a connection target DU, the target DU sends a user plane data packet carrying downlink tunnel information of the target DU to the CU-UPF network element according to the first information, wherein the downlink tunnel information is used for establishing downlink user plane connection between the target DU and the CU-UPF network element.

In the embodiment of the application, when a DU of a RAN accessed by a terminal device is switched, a target CU-CP may authorize a user plane data packet of the target DU to which the terminal device needs to switch to have a right to send control plane data, so that downlink tunnel information may be sent to a CU-UPF network element by using the user plane data packet, thereby completing updating of a user plane context between the target DU and the CU-UPF network element accessed after the terminal device is switched, which may avoid performing reconstruction of an F1 user plane context between the target DU and the CU-UPF network element, thereby reducing a switching delay, and improving problems of large service delay and large signaling overhead caused by reconstruction of an F1 interface.

In one possible design, a target DU acquires uplink tunnel information from a source CU-CP through the target CU-CP, wherein the uplink tunnel information is uplink tunnel information connected with a second F1 user plane between a CU-UPF network element and the source DU; the target DU establishes uplink user plane connection between the target DU and the CU-UPF network element according to the uplink tunnel information and the uplink tunnel information of the target DU; so that the target DU receives uplink data from the terminal device via the uplink user plane connection.

In one possible implementation, the method may further include: the target DU can also send verification information to the CU-UPF network element through a user plane data packet, the CU-UPF network element determines whether the target DU has the right to acquire the uplink tunnel information according to the verification information, when the CU-UPF network element determines that the target DU has the right to acquire the uplink tunnel information, the uplink tunnel information of the CU-UPF network element is sent to the target DU, otherwise, the uplink tunnel information is not sent.

In an eighth aspect, an embodiment of the present application provides a communication method, where a scenario in which a terminal device switches from a source DU of a source RAN to a target DU of a target RAN in different RAN services is provided, and a network architecture in which the method is applied is that a CU and the DU of the RAN are separated, and a UPF network element and a CU-UP are combined to form one network element. The method may be performed by a CU-UPF network element or an internal chip of the CU-UPF network element, the method comprising: when a terminal device is switched from a source DU of a source wireless access network device to a target DU of a target wireless access network device, a CU-UPF network element receives a user plane data packet of the target DU from the target wireless access network device, wherein the user plane data packet carries downlink tunnel information of the target DU, and the CU-UPF network element consists of a user plane entity CU-UP corresponding to a centralized unit CU of the target wireless access network device and a user plane function UPF network element; and the CU-UPF network element establishes a first F1 user plane connection according to the downlink tunnel information and the downlink tunnel information of the CU-UPF network element, namely the downlink user plane connection between the target DU and the CU-UPF network element is established.

In one possible design, a CU-UPF network element sends uplink tunnel information to a target DU through a target CU-CP; the uplink tunnel information is uplink tunnel information of a second F1 user plane connection between the CU-UPF network element and the source DU, where the uplink tunnel information and the downlink tunnel information include at least one of an internet protocol IP address and a tunnel endpoint identifier. The target DU establishes uplink user plane connection between the target DU and the CU-UPF network element according to the uplink tunnel information and the uplink tunnel information of the target DU; so that the target DU receives uplink data from the terminal device via the uplink user plane connection.

In a ninth aspect, the present application provides a communication device, which may be a CU-CP or a chip disposed inside the CU-CP. The communication device has a function implemented by the CU-CP or a chip disposed inside the CU-CP, for example, the communication device includes a module or a unit or a means (means) corresponding to the step of performing the first aspect or the fifth aspect, and the function or the unit or the means may be implemented by software, or implemented by hardware executing corresponding software.

In one possible design, the communication device includes a processing unit, a communication unit, where the communication unit may be configured to send and receive signals to and from the communication device to enable communication between the communication device and other devices, for example, the communication unit is configured to receive a first message from the relay UE; the processing unit may be adapted to perform some internal operations of the communication device. The functions performed by the processing unit, the communication unit may correspond to the steps referred to in the above aspects of the CU-CP.

In one possible design, the communication device includes a processor, and may further include a transceiver for transceiving signals, the processor executing program instructions to implement the method in any possible design or implementation of the above aspects. Wherein the communications apparatus can further include one or more memories for coupling with the processor. The one or more memories may be integrated with the processor or separate from the processor, which is not limited in this application. The memory may hold the necessary computer programs or instructions to implement the functions involved in the aspects described above. The processor may execute computer programs or instructions stored by the memory that, when executed, cause the communication device to implement the method in any possible design or implementation referred to by the aspects CU-CP described above.

In one possible design, the communication device comprises a processor and a memory, which may hold the necessary computer programs or instructions to implement the functionality referred to in the first aspect above. The processor may execute computer programs or instructions stored by the memory that, when executed, cause the communication device to implement the methods in any possible design or implementation referred to by the above aspects of CU-CP.

In one possible design, the communication device includes at least one processor and an interface circuit, where the at least one processor is configured to communicate with other devices through the interface circuit and to perform the method performed by the CU-CP in any possible design or implementation of the above aspects.

In a tenth aspect, the present application provides a communication device, which may be a CU-UPF network element or a chip disposed inside the CU-UPF network element. The communication device has functions implemented by the CU-UPF network element or a chip disposed inside the CU-UPF network element, for example, the communication device includes modules or units or means (means) corresponding to the steps for implementing the second aspect, the fourth aspect, the sixth aspect, and the eighth aspect, and the functions or units or means may be implemented by software, hardware, or hardware.

In one possible design, the communication device includes a processing unit, a communication unit, where the communication unit may be configured to send and receive signals to and from the communication device to enable communication between the communication device and other devices, for example, the communication unit is configured to receive a first message from the relay UE; the processing unit may be adapted to perform some internal operations of the communication device. The functions performed by the processing unit, the communication unit may correspond to the steps involved in the above-described aspects of the CU-UPF network element.

In one possible design, the communication device includes a processor, and may further include a transceiver for transceiving signals, the processor executing program instructions to perform the method in any possible design or implementation of the above aspects. Wherein the communications apparatus can further comprise one or more memories for coupling with the processor. The one or more memories may be integrated with the processor or separate from the processor, which is not limited in this application. The memory may hold the necessary computer programs or instructions to implement the functions involved in the aspects described above. The processor may execute computer programs or instructions stored by the memory that, when executed, cause the communication device to implement the methods in any possible design or implementation referred to by the above aspects of the CU-UPF network element.

In one possible design, the communication device comprises a processor and a memory, which may hold the necessary computer programs or instructions to implement the functionality referred to in the first aspect above. The processor may execute computer programs or instructions stored by the memory that, when executed, cause the communication device to implement the methods in any possible design or implementation referred to by the above aspects of the CU-UPF network element.

In one possible design, the communication device includes at least one processor and an interface circuit, where the at least one processor is configured to communicate with other devices through the interface circuit and to perform the method performed by the CU-UPF network element in any possible design or implementation of the above aspects.

In an eleventh aspect, the present application provides a communication apparatus, which may be a target DU or a chip disposed inside the target DU. The communication device has a function implemented by the target DU or a chip disposed inside the target DU, for example, the communication device includes a module or a unit or means (means) corresponding to the step of executing the third aspect, the seventh aspect, or the sixth aspect, and the function or the unit or the means may be implemented by software, or implemented by hardware executing corresponding software.

In one possible design, the communication device includes a processing unit, a communication unit, where the communication unit may be configured to send and receive signals to and from the communication device to enable communication between the communication device and other devices, for example, the communication unit is configured to receive a first message from the relay UE; the processing unit may be adapted to perform some internal operations of the communication device. The functions performed by the processing unit and the communication unit may correspond to the steps involved in the above-described aspects of the target DU.

In one possible design, the communication device includes a processor, and may further include a transceiver for transceiving signals, the processor executing program instructions to perform the method in any possible design or implementation of the above aspects. Wherein the communications apparatus can further include one or more memories for coupling with the processor. The one or more memories may be integrated with the processor or separate from the processor, which is not limited in this application. The memory may hold the necessary computer programs or instructions to implement the functions involved in the aspects described above. The processor may execute computer programs or instructions stored by the memory that, when executed, cause the communication device to implement the methods of any possible design or implementation to which the above aspects of the target DU pertain.

In one possible design, the communication device comprises a processor and a memory, which may hold the necessary computer programs or instructions to implement the functionality referred to in the first aspect above. The processor may execute computer programs or instructions stored by the memory that, when executed, cause the communication device to implement the methods of any possible design or implementation to which the above aspects of the target DU pertain.

In one possible design, the communication device includes at least one processor and an interface circuit, where the at least one processor is configured to communicate with other devices via the interface circuit and to perform the method performed by the target DU in any of the possible designs or implementations of the aspects described above.

In a twelfth aspect, the present application provides a computer-readable storage medium having computer-readable instructions stored thereon that, when read and executed by a computer, cause the computer to perform the method of any one of the possible designs of the above aspects.

In a thirteenth aspect, the present application provides a computer program product which, when read and executed by a computer, causes the computer to perform the method of any one of the possible designs of the various aspects described above.

In a fourteenth aspect, an embodiment of the present application provides a communication system, where the communication system includes CU-CP and CU-UPF network elements, where:

the CU-CP may be adapted to perform any one of the methods of the first aspect or the first aspect described above.

The CU-UPF network element may be adapted to perform the second aspect or any of the methods of the second aspect.

In a fifteenth aspect, an embodiment of the present application provides a communication system, where the communication system includes a target DU and a CU-UPF network element, where:

the target DU may be adapted to perform any one of the methods of the third aspect or the third aspect described above.

The CU-UPF network element may be adapted to perform any one of the methods of the fourth aspect or the fourth aspect described above.

In a sixteenth aspect, an embodiment of the present application provides a communication system, where the communication system includes a target CU-CP and CU-UPF network element of a target radio access network device, where:

the target CU-CP of the target radio access network device may be adapted to perform any one of the methods of the fifth or fifth aspects above.

The CU-UPF network element may be adapted to perform any one of the methods of the sixth aspect or the sixth aspect described above.

In a seventeenth aspect, an embodiment of the present application provides a communication system, where the communication system includes a target DU and CU-UPF network element of a target radio access network device, where:

the target DU of the target radio access network device may be configured to perform any one of the methods in the seventh aspect or the seventh aspect.

The CU-UPF network element may be adapted to perform any one of the methods of the eighth aspect or the eighth aspect described above.

In an eighteenth aspect, the present application provides a chip comprising a processor coupled to a memory for reading and executing a software program stored in the memory to implement the method in any one of the possible designs of the various aspects described above.

Drawings

Fig. 1 is a schematic diagram of a communication system according to an embodiment of the present application;

fig. 2A to fig. 2C are schematic diagrams illustrating a separated architecture of a radio access network device according to an embodiment of the present application;

fig. 3 is a schematic diagram of a RAN handover procedure of a terminal device in the prior art;

fig. 4A is a schematic diagram of a communication system suitable for use in embodiments of the present application;

fig. 4B to fig. 4C are schematic diagrams of a user plane protocol and a control plane protocol provided by an embodiment of the present application;

fig. 5A and 5B are schematic diagrams of a switching scenario applicable to the embodiment of the present application;

fig. 6 is a schematic diagram of a first communication method according to an embodiment of the present application;

fig. 7A and fig. 7B are schematic diagrams of a communication method in a handover scenario according to an embodiment of the present application;

fig. 8 is a schematic diagram of a second communication method according to an embodiment of the present application;

fig. 9A and fig. 9B are schematic diagrams of a communication method in a handover scenario according to an embodiment of the present application;

fig. 10 is a schematic diagram of a second communication method according to an embodiment of the present application;

fig. 11A and fig. 11B are schematic diagrams of a communication method in a handover scenario according to an embodiment of the present application;

fig. 12 is a schematic diagram of a third communication method according to an embodiment of the present application;

fig. 13A and fig. 13B are schematic diagrams of a communication method in a handover scenario according to an embodiment of the present application;

fig. 14 is a schematic structural diagram of a communication device according to an embodiment of the present application;

fig. 15 is a schematic structural diagram of a communication device according to an embodiment of the present application;

fig. 16 is a schematic structural diagram of a communication device according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more clear, the present application will be further described in detail with reference to the accompanying drawings.

First, a communication system to which the technical solution provided in the present application is applicable will be described.

The technical solution provided by the present application is applicable to various communication systems, such as a Long Term Evolution (LTE) system, a fifth generation (5 g) communication system, and other similar communication systems. Fig. 1 illustrates a network architecture diagram of a 5G communication system. Wherein:

terminal equipment, which may include handheld devices, in-vehicle devices, wearable devices, computing devices or other processing devices connected to wireless modems having wireless communication capabilities, as well as various forms of User Equipment (UE), mobile Stations (MS), terminal equipment (terminal equipment), and the like.

A (radio access network (R) AN device may be used to implement functions such as a radio physical layer function, radio resource management, radio access control, and mobility management. The RAN device may include a base station, for example, an access Node (AP), a next generation Node B (gNB), a next generation evolved Node B (ng-eNB, gNB), a Transmission Receive Point (TRP), a Transmission Point (TP), or some other access Node in a 5G system. It is to be understood that, in the following description, the (R) AN devices are collectively referred to as RAN devices for convenience of description.

A User Plane Function (UPF) network element, which is a functional network element of a user plane and can be connected to an external data network, and the main functions include: routing and transmission of data packets, packet detection, service usage reporting, qoS processing, lawful interception, uplink packet detection, downlink data packet storage and other user plane related functions.

The AMF network element comprises the following main functions: connection management, mobility management, registration management, access authentication and authorization, reachability management, security context management, and other access and mobility related functions.

The SMF network element has the main functions of: session management (e.g., session establishment, modification, and release, including tunnel maintenance between the UPF and the RAN), selection and control of the UPF, service and Session Continuity (SSC) mode selection, roaming, and other session-related functions.

PCF network elements, whose main functions include: and unifying policy making, providing policy control, obtaining subscription information related to policy decision and other policy related functions.

An Application Function (AF) network element may be an application control platform of a third party or an equipment deployed by an operator, and its main function includes providing application-related information and providing services for a plurality of application servers.

A Data Network (DN) has a main function of providing specific data services, such as operator services, internet access or third party services.

As shown in fig. 2A, CU/DU separation is an important characteristic in 5G, and by splitting the RAN into a centralized processing node (CU) and a distributed processing node (DU), the base station network can be flexibly adjusted, and good gains are obtained for load balancing and resource maximum utilization. In addition, under the framework, better support is provided for solving the tidal effect, deploying double connections, calculating edges, shunting services and intelligently operating and maintaining.

Therein, the radio access network device may be divided into a CU and at least one DU. The CU may be configured to manage or control at least one DU, and may also be referred to as a CU connected to at least one DU. This structure can separate the protocol layers of the radio access network equipment in the communication system, wherein part of the protocol layers are centrally controlled by the CU, and the rest or all of the functions of the protocol layers are distributed in the DU, and the DU is centrally controlled by the CU. Taking radio access network equipment as an example of a gNB, a protocol layer of the gNB includes a Radio Resource Control (RRC) layer, a Service Data Adaptation Protocol (SDAP) layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, a media access control sublayer (MAC) layer, and a physical layer. For example, the CU may be configured to implement the functions of the RRC layer, the SDAP layer, and the PDCP layer, and the DU may be configured to implement the functions of the RLC layer, the MAC layer, and the physical layer. The embodiment of the present application does not specifically limit the protocol stacks included in the CU and the DU.

The centralized processing node may be further divided into a control plane entity (CU-CP) of the centralized processing node and a user plane entity (CU-user plane, CU-UP) of the centralized processing node according to different functions. Wherein, the CU-CP can be used for control plane management, and the CU-UP can be used for user plane data transmission. The interface between the CU-CP and the CU-UP may be an E1 interface. The interface between the CU-CP and the DU may be F1-C for transport of control plane signaling. The interface between CU-UP and DU can be F1-U for user plane data transmission. And the CU-UP can be connected through an Xn-U port to carry out user plane data transmission. In other words, taking the gNB as an example, as shown in FIG. 2B, under the CU/DU split architecture, the gNB is broken down into gNB-CU-CP, gNB-CU-UP and gNB-DU. The interface between the gNB-CU-CP and the gNB-DU may be F1-C, and the interface between the gNB-CU-UP and the gNB-DU may be F1-U. For another example, as shown in fig. 2C, taking the gNB as an example, under the CU/DU separation architecture, the gNB-CU-CP of the gNB controls the gNB-CU-UP through the E1 interface, and the SMF network element controls the UPF network element through the N4 interface.

In the related art, under the above-mentioned CU/DU separation architecture of RAN, a UPF network element and a CU-UP are independently deployed, a RAN handover procedure of a terminal device is shown in fig. 3, and in fig. 3, taking a gNB as an example, a schematic flow diagram illustrating a UE handover procedure from a source gNB-DU to a target gNB-DU is exemplarily shown, where an interaction procedure between each network element or device includes:

in step 301, the ue sends a measurement report to the source gNB-DU of the gNB.

The source gNB-DU forwards the measurement report to the gNB-CU-CP via an RRC message, step 302.

For example, the source gNB-DU forwards the measurement report to the gNB-CU-CP via an uplink RRC TRANSFER MESSAGE (UL RRC MESSAGE TRANSFER).

In step 303, the gNB-CU-CP determines that the UE needs to be switched from the source gNB-DU to the target gNB-DU of the gNB based on the received measurement report, and sends a UE context setup request to the gNB-CU-UP, the UE context setup request requesting uplink tunnel information of the gNB-CU-UP in the user plane context of the F1-U interface between the gNB-CU-UP and the source gNB-DU.

Step 304, the gNB-CU-UP sends a UE context setup response to the gNB-CU-CP, the UE context setup response including uplink tunnel information for the gNB-CU-UP in the user plane context of the F1-U interface between the gNB-CU-UP and the source gNB-DU.

Step 305, when the gNB-CU-CP determines that the UE needs to be switched from the source gNB-DU to the target gNB-DU, the gNB-CU-CP sends a UE context establishment request to the target gNB-DU, wherein the UE context establishment request comprises uplink tunnel information of the gNB-CU-UP, and meanwhile, the UE context establishment request is used for requesting F1-U downlink tunnel port information of the target gNB-DU.

And step 306, the target gNB-DU sends a UE context establishment response to the gNB-CU-CP, wherein the UE context establishment response comprises the F1-U downlink tunnel port information of the target gNB-DU.

In step 307, the gNB-CU-CP sends a UE context modification request to the source gNB-DU, wherein the UE context modification request comprises an RRC Reconfiguration (RRC Reconfiguration) message for instructing the UE to end the connection with the source gNB-DU and establish the connection with the target gNB-DU through the random access procedure.

In step 308, the source gNB-DU forwards the RRC Reconfiguration (RRC Reconfiguration) message to the UE.

In step 309, the source gNB-DU sends a downlink data transmission status (downlink data transmission status) to the gNB-CU-CP, where the downlink data transmission status is used to instruct the gNB-CU-CP to stop sending downlink data to the UE.

In step 310, the source gNB-DU sends a UE context modification response to the gNB-CU-CP. The UE context modification response includes the source gNB-DU disconnecting from the UE.

In step 311, the gNB-CU-CP sends a F1 interface user plane context modification request to the gNB-CU-UP, where the modification request includes F1-U downlink tunnel port information of the target gNB-DU for requesting to establish an F1 interface downlink user plane connection between the gNB-CU-UP and the target gNB-DU side.

And step 312, the gNB-CU-UP modifies and updates the generated F1 interface user plane context according to the F1-U downlink tunnel port information of the target gNB-DU and the F1-U downlink tunnel port information of the gNB-CU-UP, establishes F1 interface downlink user plane connection, and sends an F1 interface user plane context modification response to the gNB-CU-CP.

Step 313, the UE disconnects from the source gNB-DU and establishes a connection with the target gNB-DU through a random access procedure.

And step 314, the target gNB-DU sends downlink data sending status information to the gNB-CU-CP, and the information is used for instructing the gNB-CU-CP to send downlink data to the target gNB-DU.

In step 315, the UE switches to the target gNB-DU and sends the RRC reconfiguration complete message to the target gNB-DU.

In step 316, the target gNB-DU forwards the RRC reconfiguration complete message to the gNB-CU-CP.

In step 317, the gNB-CU-CP instructs the source gNB-DU to delete the relevant UE context and to release the relevant resources occupied by the context.

In step 318, the source gNB-DU sends a UE context release complete message to the gNB-CU-CP.

Step 319, the gNB-CU-CP sends a request to the gNB-CU-UP to release the F1-U interface user plane context between the gNB-CU-UP and the source gNB-DU.

Step 320, the gNB-CU-UP releases the F1-U interface user plane context between the gNB-CU-UP and the source gNB-DU and sends a release complete message to the gNB-CU-CP.

Currently, a CU and a sinking User Plane Function (UPF) network element are usually deployed in the same physical machine room, and for the considerations of reducing data plane transmission hops, saving cost, setting data plane security nodes in a core network, and the like, it is very likely that the UPF network element and the CU-UP are combined into one network element, that is, the CU-UP is combined with the sinking UPF network element and is marked as the CU-UPF network element, and the CU-UPF network element is uniformly scheduled and managed by a Session Management Function (SMF) network element. During PDU session transmission, CU-UP can directly communicate with UPF network elements which are combined together, transmission distance is short, communication speed is high, and resource utilization rate is improved. In a closed setting scenario, fig. 4A illustrates a network architecture diagram of a 5G communication system. The interface between the gNB-CU-CP and the gNB-DU can be F1-C, the interface between the gNB-DU and the CU-UPF network element can be F1-U, the interface between the gNB-CU-CP and the CU-UPF network element can be E1, and the SMF network element controls the CU-UPF network element through an N4 interface.

It should be noted that, in the embodiment of the present application, the F1 interface is an interface between functional entities inside a RAN, for example, under the above-mentioned CU/DU separation architecture of the RAN, the F1 interface may be an interface between a DU inside the RAN and a CU inside the RAN. The F1 interface may also be referred to as a F1 interface, and for convenience of description, in the embodiments of the present application, the F1 interface may be referred to as the F1 interface, but the name is not limited.

The F1 interface according to the embodiment of the present application supports a user plane protocol and a control plane protocol. For example, as shown in fig. 4B, a schematic diagram of a protocol stack of a control plane protocol provided in an embodiment of the present application is shown.

In fig. 4B, the peer-to-peer protocol between the terminal device and the CU-CP of the RAN includes a Radio Resource Control (RRC) layer and a PDCP layer. The protocol for peering between the end devices and the DUs of the RAN includes an RLC layer, a MAC layer, and a PHY layer.

The peer-to-peer protocol includes an F1 application protocol (F1 AP) layer, a Stream Control Transport Protocol (SCTP) layer, and an IP layer. Optionally, the control plane protocol layer of the F1 interface further includes one or more of a PDCP layer, an IPsec layer, and a data packet transport layer security (DTLS) layer. In one possible implementation, the IPsec layer, PDCP layer, or DTLS layer is located above the IP layer and below the F1AP layer.

For example, as shown in fig. 4C, a schematic diagram of a protocol stack of a user plane protocol provided in the embodiment of the present application is shown. In fig. 4C, the link between the terminal device and the CU-CP includes the terminal device, the CU _ UPF network element, and the CU-CP.

In fig. 4C, the peer Protocol layers between the terminal device and the CU-UP include a Service Data Attachment Protocol (SDAP) layer and a Packet Data Convergence Protocol (PDCP) layer. The protocol for peer-to-peer between the terminal device and the DU includes a Radio Link Control (RLC) layer, a Medium Access Control (MAC) layer, and a Physical (PHY) layer.

The peer-to-peer Protocol includes a General Packet Radio Service (GPRS) tunneling Protocol User Plane (GTP-U) layer, a User Datagram Protocol (UDP) layer, and an Internet Protocol (IP) layer between the DUs of the CU-UPF network element and the RAN. Optionally, the user plane protocol layer of the F1 interface further includes a PDCP layer and/or an IP Security (IPsec) layer. In one possible implementation, the IPsec layer or the PDCP layer is located above the IP layer and below the GTP-U layer.

It is to be understood that the protocol stack architecture shown in fig. 4B to 4C in the embodiment of the present application is merely an example, and the method provided in the embodiment of the present application is not dependent on the example, but makes the method provided in the embodiment of the present application easier to understand through the example.

Considering that, under the architecture that the UPF network element and the CU-UP are combined as one network element, since the control of the qnb-CU-CP on the CU-UPF network element is already cancelled, the PDCP and SDAP configuration (SDAP Config) messages related to security and quality of service Flow (QoS Flow) control need to be issued to the CU-UPF network element through the path of CU-CP- > AMF- > SMF- > CU-UPF at the control plane. When the terminal equipment is switched over from the RAN, the interface of the CU-UPF needs to be changed, at this time, the context modification message of the user plane/the control plane of the F1 interface needs to be forwarded through the path of the gNB-CU-CP- > AMF- > SMF- > CU-UPF, the signaling flow is too long, and the time delay requirement of terminal switching can not be met.

In order to solve the above problem, an embodiment of the present application provides a communication method and apparatus, in the method, control port information is pre-sent in a PDU session establishment procedure through an SMF, and when a gbb-CU-CP is instructed to perform a gbb-DU handover at a terminal device, a preset control port is used to control a PDU session to quickly complete the gbb-DU handover, or a SMF network element authorizes a user plane data packet to control the PDU session to quickly complete the gbb-DU handover.

It should be understood that a scenario in which a DU of a RAN is switched in this embodiment is not limited to a scenario in which a terminal device switches between RAN devices, and may also be another scenario in which a Radio Bearer (Radio Bearer) may be switched between RAN devices. For example, when the terminal device is restored from a Radio Resource Control (RRC) inactive state (inactive) to an RRC connected state (connected), handover of a Radio Bearer (Radio Bearer) between RAN devices may also occur. For another example, in a scenario of dual connection (dual connection) in which the terminal device establishes a PDU session with the master RAN device and the slave RAN device, a Radio Bearer (Radio Bearer) may also be handed over from the master RAN device to the slave RAN device, or from the slave RAN device to the master RAN device. These scenarios are also applicable to the embodiments of the present application.

The network architecture and the service scenario described in the embodiment of the present application are for more clearly illustrating the technical solution of the embodiment of the present application, and do not form a limitation on the technical solution provided in the embodiment of the present application, and it can be known by a person of ordinary skill in the art that the technical solution provided in the embodiment of the present application is also applicable to similar technical problems with the evolution of the network architecture and the occurrence of a new service scenario.

The communication method provided by the present application is described in detail below with reference to specific embodiments. It is to be understood that the terms first, second, etc. used herein are used for descriptive purposes only and are not to be construed as indicating or implying relative importance, nor order, etc. For example, in the following description, a source RAN corresponding to a terminal device before handover is also referred to as a first RAN, and a target RAN corresponding to the terminal device after handover is also referred to as a second RAN; the corresponding source DU before the terminal device is switched is also referred to as a first DU, and the corresponding target DU after the terminal device is switched is also referred to as a second DU; the corresponding source CU-CP before the terminal equipment is switched is also called as a first CU-CP, and the corresponding target CU-CP after the terminal equipment is switched is also called as a second CU-CP.

The following description will be made by dividing into a scenario one in which the terminal device switches from a first DU of the RAN to a second DU of the RAN within the range of the CU service of the same RAN, and a scenario two to the communication method provided by the embodiment of the present application. Illustratively, as shown in fig. 5A, taking RAN as the gNB for example, the UE is connected to a first gNB-DU of the gNB before handover, and the UE is connected to a second gNB-DU of the gNB after handover. In scenario two, the terminal device switches from the DU of the first RAN to the DU of the second RAN within the scope of different RAN services. Illustratively, as shown in fig. 5B, taking RAN as the gNB for example, the UE is connected to a first gNB-DU of a first gNB before handover, and the UE is connected to a second gNB-DU of a second gNB after handover.

Scene one

In the first embodiment, with reference to the description of the first scenario, as shown in fig. 6, a flowchart of a first communication method provided in the embodiment of the present application is shown. Referring to fig. 6, the method includes the following steps.

In step 601, the CU-CP of the ran receives control port information from the SMF network element.

The control port information may also be referred to as a temporary E1 port, and the control port indicated by the control port information is a control port of the CU-UPF network element and is a control port corresponding to the PDU session of the terminal device. That is, the control ports are one-to-one corresponding to sessions.

In a possible implementation, the control port information may be carried in an N2 message, and the SMF network element may send the control port information to the CU-CP of the RAN through the AMF network element.

In step 602, when the CU-CP of the ran determines that the terminal device needs to switch from the first DU to the second DU, the CU-CP acquires the downlink tunnel information of the second DU from the second DU.

Specifically, the terminal device may send a measurement report to the CU-CP of the RAN through the first DU that is currently accessed, and the CU-CP of the RAN determines that the terminal device needs to be switched to the second DU according to the measurement report from the terminal device. The measurement report may include information such as the received signal power of the DU of the surrounding RAN measured by the UE.

The first DU is a source DU accessed before the terminal device is switched, the second DU is a target DU accessed after the terminal device is switched, and the downlink tunnel information of the second DU may include at least one of an IP address and a GTP Tunnel Endpoint Identifier (TEID). Illustratively, the downlink tunnel information of the second DU may include a first IP address, where the first IP address is an IP address used when the second DU communicates with the CU-UPF network element.

In a possible implementation, a specific way for the CU-CP to obtain the downlink tunnel information of the second DU from the second DU may be: when the CU-CP determines that the terminal device needs to be switched to the second DU, the CU-CP may first send a request message to the second DU, where the request message is used to request downlink tunnel information of the second DU, and the second DU sends a response message to the CU-CP after receiving the request message, where the response message carries the downlink tunnel information.

Step 603, in the process that the terminal device switches from the first DU to the second DU, the CU-CP sends the downlink tunnel information to the CU-UPF network element through the control port.

And step 604, the CU-UPF network element establishes the F1 downlink user plane connection between the CU-UPF network element and the second DU according to the downlink tunnel information of the second DU and the downlink tunnel information of the CU-UPF network element.

The F1 downlink user plane connection between the CU-UPF network element and the second DU is hereinafter also referred to as the first F1 user plane connection. And the downlink tunnel information of the CU-UPF network element is the downlink tunnel information of the second F1 user interface connection between the CU-UPF network element and the first DU.

The downlink tunnel information of the CU-UPF network element may include at least one of an IP address and a GTP Tunnel Endpoint Identifier (TEID). Illustratively, the downlink tunnel information of the CU-UPF network element may include a second IP address, where the second IP address is an IP address used by the CU-UPF network element when communicating with the CU-UPF network element through the first DU.

In one possible implementation, the method may further include: the CU-CP acquires the uplink tunnel information of the CU-UPF network element from the CU-UPF network element through the control port, the CU-CP sends the uplink tunnel information of the CU-UPF network element to the target DU, and the second DU establishes uplink user plane connection between the second DU and the CU-UPF network element according to the uplink tunnel information of the CU-UPF network element and the uplink tunnel information of the target DU, so that the second DU can receive uplink data from the terminal equipment through the uplink user plane connection.

The verification information in the embodiment of the application may be certificate information, and the authority is verified according to the certificate information; it may also be an indication information indicating the associated rights.

In addition, the verification information is also used to determine whether the CU-CP has the right to modify the upstream tunnel information.

In the embodiment of the application, when a DU of a RAN accessed by a terminal device is switched, a CU-CP may communicate with a CU-UPF network element based on a control port acquired from a core network element in advance, and the CU-UPF network element may complete updating of a user plane context between a second DU and a CU-UPF network element accessed after the terminal device is switched based on downlink tunnel information of the second DU acquired from a CU-UP by the control port, so that the re-establishment of an F1 user plane interface between the second DU and the CU-UPF network element may be avoided, thereby reducing a switching delay, and improving problems of large service delay and large signaling overhead caused by the re-establishment of the F1 interface.

In fig. 7A, the embodiment of the present application further exemplifies the above communication method by taking a UE switching from a first gNB-DU connected to a gNB to a second gNB-DU of the gNB.

Step 700, in the PDU session establishment process, the SMF network element sends CU-UPF network element side control port information corresponding to the PDU session to the gNB-CU-CP of the gNB through the AMF network element.

In other words, the SMF network element issues CU-UPF network element side control port information to the gNB-CU-CP when the PDU session is established, so that the gNB-CU-CP can establish communication with the CU-UPF network element through the control port indicated by the control port information, and thus the gNB-CU-CP of the gNB can send control plane data to the CU-UPF network element. Equivalently, the SMF network element authorizes the gNB-CU-CP to have the right to modify the user plane context of the CU-UPF network element.

In a possible embodiment, the first message may further include authentication information, for example, the authentication information is a Token (Token). Alternatively, the SMF network element sends the authentication information to the gNB-CU-CP through other messages. The verification information is used for the CU-UPF network element to determine the authority of the gNB-CU-CP, for example, used for the CU-UPF network element to determine whether the gNB-CU-CP has the authority of acquiring the uplink tunnel information of the CU-UPF network element, or used for the CU-UPF network element to determine whether the gNB-CU-CP has the authority of modifying the user plane context of the CU-UPF network element, or used for the CU-UPF network element to determine whether the gNB-CU-UPCP has the authority of modifying the F1 interface of the CU-UPF network element.

In step 701 and step 702, the UE sends a measurement report to the gNB-CU-CP through the first gNB-DU.

The first gNB-DU is a source gNB-DU connected before the UE is switched, the measurement report can comprise information such as received signal power of surrounding gNB-DUs measured by the UE, the UE sends the measurement report to the gNB-CU-CP, and the gNB-CU-CP determines whether the UE needs to switch the gNB-DU.

And step 703, when the gNB-CU-CP determines that the UE needs to switch the gNB-DU, the gNB-CU-CP requests the upstream tunnel information of the CU-UPF network element from the CU-UPF network element through the control port.

The uplink tunnel information of the CU-UPF network element refers to uplink tunnel information of the CU-UPF network element in the F1 user plane connection between the CU-UPF network element and the first gNB-DU, and for example, the uplink tunnel information of the CU-UPF network element may include an IP address and a GTP tunnel endpoint identifier.

In a possible embodiment, in this step 703, the gNB-CU-CP may further send authentication information to the CU-UPF network element through the control port, for example, the gNB-CU-CP may further send a BEARER CONTEXT MODIFICATION REQUEST (BEARER CONTEXT MODIFICATION REQUEST) to the CU-UPF network element through the control port, where the BEARER CONTEXT MODIFICATION REQUEST carries the Token (Token). When included in step 703, the method embodiment may further include step 704 as follows.

And step 704, the CU-UPF network element verifies the gNB-CU-CP authority according to the verification information. For example, the CU-UPF network element determines whether the gNB-CU-CP has the authority to acquire the uplink tunnel information according to the Token (Token). If so, the CU-UPF network element performs step 705, otherwise, step 705 is not performed.

And step 705, the CU-UPF network element sends the uplink tunnel information of the CU-UPF network element to the gNB-CU-CP.

And 706, forwarding the uplink tunnel information of the CU-UPF network element to the second gNB-DU by the gNB-CU-CP, and additionally sending a request to the second gNB-DU, wherein the request is used for requesting the downlink tunnel information of the second gNB-DU.

And step 707, after the second gNB-DU receives the uplink tunnel information of the CU-UPF network element, establishing an F1 uplink user plane connection between the second gNB-DU and the CU-UPF network element according to the uplink tunnel information of the CU-UPF network element and the uplink tunnel information of the second gNB-DU, so that the second gNB-DU receives the uplink data of the terminal device. And in addition, the second gNB-DU also sends the downlink tunnel information of the second gNB-DU to the gNB-CU-CP.

In step 708 and step 709, the gNB-CU-CP sends a handover command to the first gNB-DU instructing the UE to switch from connecting the first gNB-DU to connecting the second gNB-DU.

For example, the Handover Command may be a UE CONTEXT MODIFICATION REQUEST (UE CONTEXT MODIFICATION REQUEST) message, where the UE CONTEXT MODIFICATION REQUEST message may include an RRC Reconfiguration Handover Command (Reconfiguration Handover Command) for instructing the UE to perform Handover, and after receiving the RRC Reconfiguration Handover Command, the UE needs to disconnect the radio connection with the first gbb-DU and attempt to access the second gbb-DU through a random access procedure.

Step 710, after the first gNB-DU sends the RRC reconfiguration signaling to the UE, the first gNB-DU stops sending downlink data to the UE.

Optionally, the first gNB-DU may further send a downlink data transmission status message to the CU-UPF network element, so as to notify the CU-UPF of the transmission condition of the downlink data packet (for example, notify which downlink data packets with SN numbers have been successfully transmitted, and mainly used to synchronize the SN numbers of the PDCP data packets).

In step 711, the first gNB-DU transmits a handover result to the gNB-CU-CP, the handover result indicating that the first gNB-DU has interrupted the radio connection with the UE and indicating that the gNB-CU-CP stops transmitting data thereto.

For example, the handover result may be carried in a UE CONTEXT MODIFICATION RESPONSE (UE CONTEXT MODIFICATION RESPONSE) message, which may include an RRC reconfiguration complete message.

And step 712, the gNB-CU-CP sends a second message to the CU-UPF network element, for example, the second message is a BEARER CONTEXT MODIFICATION REQUEST (BEARER CONTEXT MODIFICATION REQUEST) message, and the second message carries the downlink tunnel information of the second gNB-DU.

It should be noted that the second message is used to modify the user plane context of the CU-UPF network element. At this time, the uplink and downlink connection between the CU-UPF and the F1 interface of the second gNB-DU is already established, and no data interaction of the user plane exists between the CU-UPF and the first gNB-DU.

And 713, the CU-UPF network element establishes F1 downlink user plane connection between the second gNB-DU and the CU-UPF network element according to the downlink tunnel information of the second gNB-DU and the downlink tunnel information of the CU-UPF network element stored by the CU-UPF network element, generates F1 user plane context information between the second gNB-DU and the CU-UPF network element, and reports the modified F1 user plane context information to the SMF network element, wherein the F1 user plane context information comprises the downlink tunnel information of the gNB-DU, and the uplink tunnel information and the downlink tunnel information of the CU-UPF network element.

In step 714, the smf network element feeds back a BEARER CONTEXT MODIFICATION RESPONSE (BEARER CONTEXT MODIFICATION RESPONSE) to the CU-UPF network element through the N4 message, where the BEARER CONTEXT MODIFICATION RESPONSE includes completion of MODIFICATION of the F1 user plane CONTEXT information.

In step 715, the CU-UPF network element sends a RESPONSE message to the gNB-CU-CP, for example, the RESPONSE message is a port CONTEXT MODIFICATION RESPONSE (BEARER CONTEXT MODIFICATION RESPONSE) message, which is used to inform the gNB-CU-CP that the CU-UPF and the F1 interface of the second gNB-DU are connected in the uplink and downlink direction and the CU-UPF and the F1 interface of the second gNB-DU are modified in the user plane.

In step 716, the ue establishes a radio connection with the second gNB-DU through a random access procedure.

In steps 717 and 718, the ue transmits an RRC Reconfiguration Complete message for reporting that the radio connection with the second gNB-DU has been established to the gNB-CU-CP through the second gNB-DU.

And step 719, after the second gNB-DU establishes a successful radio connection with the UE, the second gNB-DU sends a downlink data sending status to the CU-UPF network element, where the downlink data sending status is used to instruct the CU-UPF network element to start sending downlink data to the second gNB-DU.

Steps 715 to 719 can be performed in parallel with step 714, i.e. the CU-UPF network element can perform steps 715 to 719 without waiting for a response message from the SMF.

In step 720 and step 721, the gNB-CU-CP instructs the first gNB-DU to release the context information of the UE, and the first gNB-DU feeds back a context release completion message of the UE to the gNB-CU-CP.

Referring to fig. 7B, in the embodiment of the present application, the SMF network element issues the CU-UPF control port information and the verification information to the gNB-CU-CP when a session is established, so as to authorize the gNB-CU-CP to modify the downlink user plane connection between the CU-UPF network element and the second gNB-DU in the gNB-DU handover flow, and finally report the modified user plane context to the SMF network element for synchronization, thereby ensuring fast handover of the gNB-DU. It should be noted that the control connection in fig. 7B is different from the conventional E1 interface, and is a temporary connection similar to the user plane connection, and is not a device-level connection of the E1 interface, and is only associated with the session service, and there is no device-level association, and the upgrade adjustment of the CU-UPF, etc., and does not affect the setting of the gNB-CU-CP.

In the embodiment of the application, when a DU of a base station connected with UE is switched, a CU-UPF acquires downlink tunnel information of a second DU by using a control port, and completes updating of a context of a downlink user plane of an F1 interface between the CU-UPF and a target DU based on the downlink tunnel information of the second DU and the downlink tunnel information of the CU-UPF, thereby avoiding service delay and signaling overhead caused by executing reconstruction of the F1 interface. Therefore, after the UE is switched, the second DU and the CU-UPF network element can carry out user plane communication of the F1 interface, so that the UE can carry out uplink and downlink data transmission as soon as possible after the switching is finished, and the influence on the service delay of the terminal is reduced.

In a second embodiment, with reference to the description of the first scenario, as shown in fig. 8, a flowchart of a second communication method provided in the embodiment of the present application is shown. The method comprises the following steps.

In step 801, a second DU of the RAN receives first information from a CU-CP of the RAN.

Wherein, the first information is used to authorize the user plane data packet sent by the second DU to have the right to transmit the control plane data. The first information may be carried in the N2 message, for example, the first message is a UE context Modification/reconstruction request (UE context Modification/Establishment request) message.

Step 802, in the process that the terminal device switches from the first DU to the second DU, the second DU sends a user plane data packet carrying downlink tunnel information of the second DU to the CU-UPF network element.

Wherein, the downlink tunnel information of the second DU may include at least one of an IP address and a GTP Tunnel Endpoint Identifier (TEID). Illustratively, the downlink tunnel information of the second DU may include a first IP address, where the first IP address is an IP address used when the second DU communicates with the CU-UPF network element.

In a possible embodiment, the CU-CP of the RAN may further obtain authentication information from the SMF network element, and the CU-CP of the RAN may send the authentication information to the second DU, so that the user plane packet sent by the second DU to the CU-UPF network element may also carry the authentication information, so that the CU-UPF network element may confirm whether the second DU has the right to request to establish the first F1 user plane connection.

And step 803, the CU-UPF network element establishes the first F1 user plane connection between the CU-UPF network element and the second DU according to the downlink tunnel information of the second DU side and the downlink tunnel information of the CU-UPF network element.

And the uplink tunnel information is the uplink tunnel information of the F1 user plane connection between the CU-UPF network element and the first DU.

The downlink tunnel information of the CU-UPF network element may include at least one of an IP address and a GTP Tunnel Endpoint Identifier (TEID). Illustratively, the downlink tunnel information of the CU-UPF network element may include a second IP address, where the second IP address is an IP address used by the CU-UPF network element side when performing communication with the CU-UPF network element through the first DU.

In one possible implementation, the method may further include: and the second DU acquires the uplink tunnel information of the CU-UPF network element from the CU-UPF network element through the CU-CP, and establishes uplink user plane connection between the second DU and the CU-UPF network element according to the uplink tunnel information of the CU-UPF network element and the uplink tunnel information of the target DU, so that the second DU can receive uplink data from the terminal equipment through the uplink user plane connection.

In one possible implementation, the method may further include: the second DU may also send verification information to the CU-UPF network element through the user plane data packet, and the CU-UPF network element determines whether the second DU has the right to acquire the uplink tunnel information according to the verification information, and sends the uplink tunnel information of the CU-UPF network element to the second DU when the CU-UPF network element determines that the second DU has the right to acquire the uplink tunnel information, otherwise, the uplink tunnel information is not sent.

In the embodiment of the application, when a DU of a RAN accessed by a terminal device is switched, a CU-CP may authorize a user plane data packet of a second DU to which the terminal device needs to be switched to have a right to send control plane data, so that downlink tunnel information may be sent to a CU-UPF network element by using the user plane data packet, thereby completing updating of a user plane context between the second DU and the CU-UPF network element accessed after the terminal device is switched, and thus, performing reestablishment of an F1 user plane context between the second DU and the CU-UPF network element may be avoided, thereby reducing a switching delay, and improving problems of large service delay and large signaling overhead caused by reestablishment of an F1 interface.

In fig. 9A, the present embodiment further exemplifies the above communication method by taking the UE switching from a first gNB-DU connected to a gNB to a second gNB-DU of the gNB.

Optionally, in step 900, during the PDU session establishment process, the SMF network element sends, to the gNB-CU-CP of the gNB through the AMF network element, verification information, where the verification information may include a Token (Token), and the verification information is used by the CU-UPF network element to determine an authority of the second gNB-DU, for example, to determine whether the second gNB-DU has an authority to acquire uplink tunnel information of the CU-UPF network element, or to determine whether the second gNB-DU has an authority to modify a user plane context of the CU-UPF network element, or to determine whether the second gNB-DU has an authority to modify an F1 interface of the CU-UPF network element, by the CU-UPF network element.

In steps 901 to 902, the ue sends a measurement report to the gNB-CU-CP via the first gNB-DU to trigger the handover procedure.

The measurement report may include information such as received signal power of surrounding gNB-DUs measured by the UE, and the UE sends the measurement report to the gNB-CU-CP, and the gNB-CU-CP determines whether the UE needs to switch the gNB-DUs.

And step 903, when the gNB-CU-CP determines that the UE needs to be switched to a second gNB-DU, the gNB-CU-CP forwards the uplink tunnel information of the CU-UPF network element to the second gNB-DU, and in addition, sends a request to the second gNB-DU, wherein the request is used for requesting to establish the F1 uplink user plane connection.

The downlink tunnel information of the second gNB-DU is used to establish an F1 downlink user plane connection between the CU-UPF network element and the second gNB-DU, where the downlink tunnel information of the second gNB-DU may include an IP address and a GTP tunnel endpoint identifier.

And 904, after the second gNB-DU receives the uplink tunnel information of the CU-UPF network element, establishing F1 uplink user plane connection between the second gNB-DU and the CU-UPF network element according to the uplink tunnel information of the CU-UPF network element and the uplink tunnel information of the second gNB-DU, so that the second gNB-DU can receive uplink data of the terminal equipment. And in addition, the second gNB-DU sends a response to the gNB-CU-CP, wherein the response comprises the completion of the establishment of the F1 uplink user plane connection.

Step 905, the gNB-CU-CP sends a handover command to the first gNB-DU, the handover command instructing the UE to switch from connecting the first gNB-DU to connecting the second gNB-DU.

Step 906, after the first gNB-DU sends the RRC reconfiguration signaling to the UE, the first gNB-DU stops sending downlink data to the UE.

And step 907, the first gNB-DU sends a Downlink Data Delivery Status message to the CU-UPF network element, and the message is used for reporting the Data transmission condition and instructing the CU-UPF to stop sending Downlink Data to the CU-UPF network element.

And 908, the first gNB-DU sends a switching result to the gNB-CU-CP, wherein the switching result is used for indicating that the first gNB-DU interrupts the wireless connection with the UE and indicating that the gNB-CU-CP stops sending data to the first gNB-DU.

In step 909, the ue establishes a radio connection with the second gNB-DU through a random access procedure.

In step 910, the second gNB-DU sends a user plane Data packet, such as a user plane Data packet, carrying Downlink tunnel information, to the CU-UPF network element, such as a Downlink Data Delivery Status (Downlink Data Delivery Status) message, where the user plane Data packet includes the Downlink tunnel information of the second gNB-DU.

In a possible embodiment, the user plane packet may further include authentication information, and when the authentication information is included in step 910, the method embodiment may further include step 911 as follows.

And 911, the CU-UPF network element carries out verification according to the verification information and the second gNB-CU authority. For example, the CU-UPF network element determines from the Token (Token) whether the second gNB-CU has the right to modify the F1 user plane connection. If so, the CU-UPF network element performs step 912, otherwise, step 912 is not performed.

And step 912, after the CU-UPF network element passes the verification, sending downlink data of the UE to the second gNB-DU.

And step 913, the CU-UPF network element modifies the F1 user plane context information between the second gNB-DU and the CU-UPF network element, and reports the modified F1 user plane context information to the SMF network element.

In step 914, the smf network element feeds back a BEARER CONTEXT MODIFICATION RESPONSE (BEARER CONTEXT MODIFICATION RESPONSE) to the CU-UPF network element via the N4 message, where the BEARER CONTEXT MODIFICATION RESPONSE includes completion of the MODIFICATION of the F1 user plane CONTEXT information.

In steps 915 and 916, the ue transmits an RRC Reconfiguration Complete message for reporting that the radio connection with the second gNB-DU has been established to the gNB-CU-CP through the second gNB-DU.

In step 917 and step 918, the gNB-CU-CP instructs the first gNB-DU to release the context information of the UE, and the first gNB-DU feeds back a context release completion message of the UE to the gNB-CU-CP.

Step 918, the smf network element feeds back a UE context modification response message to the gNB-CU-CP through the AMF network element, where the UE context modification response message includes the updated information of the F1 user plane context.

Referring to fig. 9B, in this embodiment, a core network element may enable a user plane data packet sent by a second DU to a CU-UPF network element to carry downlink tunnel information of the second DU by authorizing user plane data, so that in a gNB-DU handover process, a downlink user plane connection between the CU-UPF network element and the second gNB-DU is modified first, and finally, a modified user plane context is reported to an SMF network element for synchronization, thereby ensuring fast handover of the gNB-DU.

In the embodiment of the application, when DUs of a base station connected with UE are switched, a second DU sends downlink tunnel information to a CU-UPF network element by using a user plane data packet, and the CU-UPF network element completes updating of the user plane context of an F1 interface between the CU-UPF and a target DU based on the downlink tunnel information of the second DU and the uplink tunnel information of the CU-UPF, so that service delay and signaling overhead caused by executing reconstruction of the F1 interface are avoided. Therefore, after the UE is switched, the second DU and the CU-UPF network element can carry out user plane communication of the F1 interface, so that the UE can carry out uplink and downlink data transmission as soon as possible after the switching is finished, and the influence on the service delay of the terminal is reduced.

Scene two

EXAMPLE III

With reference to the description of the scenario two, as shown in fig. 10, a flow diagram of a third communication method provided in the embodiment of the present application is shown. Referring to fig. 10, the method includes the following steps.

The second CU-CP of the second RAN receives control port information from the SMF network element via the first CU-CP of the first RAN, step 1001.

The control port indicated by the control port information may also be referred to as a temporary E1 port, and the control port indicated by the control port information is a control port of the CU-UPF network element and is a control port corresponding to the PDU session of the terminal device. That is, the control ports are one-to-one corresponding to sessions.

In one possible implementation, the control port information may be carried in an N2 message.

Step 1002, when the terminal device switches from a first DU of a first RAN to a second DU of a second RAN, a second CU-CP acquires downlink tunnel information of the second DU for establishing a first F1 user plane connection from the second DU.

Specifically, the terminal device may send a measurement report to the CU-CP of the first RAN through the currently accessed first DU, the CU-CP of the first RAN forwards the measurement report to the CU-CP of the second RAN, and the CU-CP of the second RAN determines that the terminal device needs to be switched to the second DU according to the measurement report from the terminal device. The measurement report may include information such as the received signal power of the DU of the surrounding RAN measured by the UE.

In a possible implementation, the specific manner in which the CU-CP obtains the downlink tunnel information of the second DU from the second DU may be referred to as step 602, and details are not repeated here.

Step 1003, in the process that the terminal device switches from the first DU to the second DU, the second CU-CP sends the downlink tunnel information to the CU-UPF network element through the control port.

And step 1004, the CU-UPF network element establishes the F1 downlink user plane connection between the CU-UPF network element and the second DU according to the downlink tunnel information of the second DU and the downlink tunnel information of the CU _ UPF network element.

The F1 downlink user plane connection between the CU-UPF network element and the second DU is also referred to herein as a first F1 user plane connection. And the downlink tunnel information of the CU-UPF network element is the downlink tunnel information of the second F1 user interface connection between the CU-UPF network element and the first DU. The downlink tunnel information of the CU-UPF network element may include at least one of an IP address and a GTP Tunnel Endpoint Identifier (TEID).

In one possible implementation, the method may further include: and a second CU-CP of the second RAN acquires the uplink tunnel information of the CU-UPF network element from the CU-UPF network element through the control port, the second CU-CP sends the uplink tunnel information of the CU-UPF network element to a second DU, and the second DU establishes uplink user plane connection between the second DU and the CU-UPF network element according to the uplink tunnel information of the CU-UPF network element and the uplink tunnel information of the target DU, so that the second DU receives uplink data from the terminal equipment through the uplink user plane connection.

In one possible implementation, the method may further include: and the second CU-CP also sends verification information to the CU-UPF network element through the control port, the CU-UPF network element determines whether the second CU-CP has the right to acquire the uplink tunnel information according to the verification information, when the CU-UPF network element determines that the second CU-CP has the right to acquire the uplink tunnel information, the uplink tunnel information of the CU-UPF network element is sent to the second CU-UPF network element, and otherwise, the uplink tunnel information is not sent.

In one possible implementation, the CU-UPF network element sends the downlink tunnel information of the second DU, and the uplink tunnel information and the downlink tunnel information of the CU-UPF network element to the core network element.

In the embodiment of the present application, in a range where a terminal device is served by different RANs, a first DU of a first RAN is switched to a second DU of a second RAN, a second CU-CP of the second RAN may communicate with a CU-UPF network element based on a control port acquired from a core network element in advance, and the CU-UPF network element may complete establishment of a downlink user plane connection between the second DU and the CU-UPF network element accessed after the terminal device is switched based on downlink tunnel information of the second DU acquired from a second CU-UP by the control port, so that execution of reconstruction of an F1 user plane interface between the second DU and the CU-UPF network element may be avoided, thereby reducing a switching delay, and improving problems of large service delay and large signaling overhead caused by reconstruction of the F1 interface.

In fig. 11A, the embodiment of the present application further exemplifies the above communication method by taking the UE switching from a first gNB-DU connected to a first gNB to a second gNB-DU of a second gNB. It should be noted that the first gNB is a source gNB accessed before the terminal is switched, the second gNB is a target gNB accessed after the terminal is switched, the first gNB-DU is a distributed unit of the source gNB, the second gNB-DU is a distributed unit of the target gNB, the first gNB-CU-CP is a control plane entity of the source gNB, and the second gNB-CU-CP is a control plane entity of the target gNB.

Step 1100, in the PDU session establishment process, the SMF network element sends the control port information of the CU-UPF network element corresponding to the PDU session to the first gNB-CU-CP of the first gNB through the AMF network element, and the first gNB-CU-CP of the first gNB forwards the control port information to the second gNB-CU-CP of the second gNB.

In other words, the SMF network element issues the CU-UPF network element side control port information to the second gNB-CU-CP when the PDU session is established, so that the second gNB-CU-CP can establish communication with the CU-UPF network element through the control port indicated by the control port information, and thus the second gNB-CU-CP of the second gNB can send control plane data to the CU-UPF network element. Equivalently, the SMF network element authorizes the second gNB-CU-CP to have the right to modify the user plane context of the CU-UPF network element.

In a possible embodiment, the first message may further include authentication information, for example, the authentication information is a Token (Token). Alternatively, the SMF network element sends the authentication information to the second gNB-CU-CP via another message. The verification information is used for the CU-UPF network element to determine the authority of the gNB-CU-CP, for example, used for the CU-UPF network element to determine whether the second gNB-CU-CP has the authority of acquiring the uplink tunnel information of the CU-UPF network element, or used for the CU-UPF network element to determine whether the second gNB-CU-CP has the authority of modifying the user plane context of the CU-UPF network element, or used for the CU-UPF network element to determine whether the second gNB-CU-CP has the authority of modifying the F1 interface of the CU-UPF network element.

In step 1101 and step 1102, the UE sends a measurement report to the gNB-CU-CP of the first gNB via the gNB-DU of the first gNB.

The first gNB-DU is a source gNB-DU connected before UE switching, the measurement report can comprise information such as the received signal power of surrounding gNB-DUs measured by the UE, the UE sends the measurement report to the first gNB-CU-CP, and the gNB-CU-CP determines whether the UE needs to switch the gNB-DU.

And step 1103, when the first gNB-CU-CP determines that the UE needs to switch the gNB-DU according to the measurement report, the first gNB-CU-CP sends a switching request to the second gNB-CU-CP, and the switching request is used for requesting the terminal equipment to switch to the second gNB-DU of the second gNB-CU-CP.

And step 1104, the second gNB-CU-CP requests the uplink tunnel information of the CU-UPF network element from the CU-UPF network element through the control port.

The uplink tunnel information of the CU-UPF network element refers to uplink tunnel information of the CU-UPF network element in the F1 user plane connection between the CU-UPF network element and the first gNB-DU, for example, the uplink tunnel information of the CU-UPF network element may include an IP address and a GTP tunnel endpoint identifier.

In a possible embodiment, in this step 1104, the second gNB-CU-CP may further send verification information to the CU-UPF network element through the control port, for example, the second gNB-CU-CP may further send a BEARER CONTEXT MODIFICATION REQUEST (BEARER CONTEXT MODIFICATION REQUEST) to the CU-UPF network element through the control port, where the BEARER CONTEXT MODIFICATION REQUEST carries the Token (Token). When the verification information is included in step 1104, the method embodiment may further include step 1105 as follows.

And step 1105, the CU-UPF network element verifies the second gNB-CU-CP right according to the verification information. For example, the CU-UPF network element determines whether the second gNB-CU-CP has the right to acquire the uplink tunnel information according to the Token (Token). If so, the CU-UPF network element performs step 1106, otherwise, step 1106 is not performed.

And step 1106, the CU-UPF network element sends the uplink tunnel information of the CU-UPF network element to the second gNB-CU-CP.

In step 1107, the second gNB-CU-CP forwards the uplink tunnel information of the CU-UPF network element to the second gNB-DU, and additionally sends a request to the second gNB-DU, where the request is used to request the downlink tunnel information of the second gNB-DU.

And step 1108, after the second gNB-DU receives the uplink tunnel information of the CU-UPF network element, establishing F1 uplink user plane connection between the second gNB-DU and the CU-UPF network element according to the uplink tunnel information of the CU-UPF network element and the uplink tunnel information of the second gNB-DU, so that the second gNB-DU receives the uplink data of the terminal equipment. And in addition, the second gNB-DU also sends the downlink tunnel information of the second gNB-DU to the gNB-CU-CP.

And step 1109, the second gNB-CU-CP sends a switching request response to the first gNB-CU-CP, wherein the switching request response comprises indication information used for indicating the UE to switch from connecting the first gNB-DU to connecting the second gNB-DU.

In steps 1110 and 1111, the first gNB-CU-CP sends a handover command to the first gNB-DU, the handover command instructing the UE to switch from connecting the first gNB-DU to connecting the second gNB-DU.

Step 1112, after the first gNB-DU sends the RRC reconfiguration signaling to the UE, the first gNB-DU stops sending downlink data to the UE.

And step 1113, the first gNB-DU sends a switching result to the first gNB-CU-CP, wherein the switching result is used for indicating that the first gNB-DU interrupts the wireless connection with the UE and indicating that the first gNB-CU-CP stops sending data to the first gNB-CU-CP.

In step 1114, the second gNB-CU-CP sends a second message to the CU-UPF network element, for example, the second message is a BEARER CONTEXT MODIFICATION REQUEST (BEARER CONTEXT MODIFICATION REQUEST) message, and the message carries the downlink tunnel information of the second gNB-DU.

And 1115, the CU-UPF network element establishes F1 downlink user plane connection between the second gNB-DU and the CU-UPF network element according to the downlink tunnel information of the second gNB-DU and the downlink tunnel information of the CU-UPF network element stored by the CU-UPF network element, generates F1 user plane context information between the second gNB-DU and the CU-UPF network element, and reports the modified F1 user plane context information to the SMF network element, wherein the F1 user plane context information comprises the downlink tunnel information of the gNB-DU, and the uplink tunnel information and the downlink tunnel information of the CU-UPF network element.

In step 1116, the smf network element feeds back a BEARER CONTEXT MODIFICATION RESPONSE (BEARER CONTEXT MODIFICATION RESPONSE) to the CU-UPF network element through the N4 message, where the BEARER CONTEXT MODIFICATION RESPONSE includes completion of MODIFICATION of the F1 user plane CONTEXT information.

In step 1117, the CU-UPF network element sends a RESPONSE message to the second gNB-CU-CP, for example, the RESPONSE message is a port CONTEXT MODIFICATION RESPONSE (BEARER CONTEXT MODIFICATION RESPONSE) message, which is used to inform the gNB-CU-CP that the CU-UPF and the second gNB-DU have completed the uplink and downlink connection of the F1 interface and the F1 interface of the CU-UPF and the second gNB-DU and the user plane CONTEXT MODIFICATION of the F1 interface.

In step 1118, the UE disconnects the first gbb-DU and establishes a connection with the second gbb-DU through a random access procedure.

In step 1119 and step 1120, the UE transmits an RRC Reconfiguration Complete message for reporting that the radio connection with the second gNB-DU has been established to the second gNB-CU-CP through the second gNB-DU.

And step 1121, after the second gbb-DU establishes a successful wireless connection with the UE, the second gbb-DU sends a downlink data sending status to the CU-UPF network element, where the downlink data sending status is used to instruct the CU-UPF network element to start sending downlink data to the second gbb-DU.

The steps 1117 to 1121 may be performed in parallel with the step 1116, that is, the CU-UPF network element may perform the steps 1117 to 1121 without waiting for the SMF response message.

In step 1122, the second gNB-CU-CP instructs the first gNB-CU-CP to release the context information of the UE.

And step 1123 and step 1124, the first gNB-CU-CP instructs the first gNB-DU to release the context information of the UE, and the first gNB-DU feeds back a context release completion message of the UE to the first gNB-CU-CP.

In step 1125, the second gNB-CU-CP reports the updated context information of the UE to the AMF network element, where the updated context information of the UE includes information of the second gNB-CU-CP serving the UE.

Referring to fig. 11B, in the embodiment of the present application, when a session is established, an SMF network element issues control port information and verification information of a CU-UPF to a target gNB-CU-CP through a source gNB-CU-CP, so that the target gNB-CU-CP is authorized to modify a downlink user plane connection between the CU-UPF network element and a second gNB-DU in a gNB-DU handover procedure, and finally, the modified user plane context is reported to the SMF network element for synchronization, thereby ensuring fast handover of the gNB-DU. It should be noted that the control connection in fig. 11B is different from the conventional E1 interface, and is a temporary connection similar to the user plane connection, and is not a device-level connection of the E1 interface, and is only associated with the session service, and there is no device-level association, and the upgrade adjustment of the CU-UPF, etc., and does not affect the setting of the target gNB-CU-CP.

In the embodiment of the application, when UE (user equipment) performs DU switching across RAN (radio access network), a CU-UPF (CU-UPF) acquires downlink tunnel information of a second DU by using a control port, and completes updating of a context of a downlink user plane of an F1 interface between the CU-UPF and a target DU on the basis of the downlink tunnel information of the second DU and the downlink tunnel information of the CU-UPF, so that service delay and signaling overhead caused by executing reestablishment of the F1 interface are avoided. Therefore, after the UE is switched, the second DU and the CU-UPF network element can carry out user plane communication of the F1 interface, so that the UE can carry out uplink and downlink data transmission as soon as possible after the switching is finished, and the influence on the service delay of the terminal is reduced.

With reference to the description of the scenario two, as shown in fig. 12, the fourth embodiment is a flowchart of a fourth communication method provided in the embodiment of the present application. Referring to fig. 12, the method includes the following steps.

In step 1201, the second DU of the second RAN receives first information from the first CU-CP of the first RAN via the second CU-CP of the second RAN, the first information being obtained by the first CU-CP of the first RAN from the SMF network element.

Step 1202, in the process that the terminal device switches from the first DU to the second DU, the second DU sends a user plane data packet carrying downlink tunnel information of the second DU to the CU-UPF network element.

Wherein the downlink tunnel information of the second DU may include at least one of an IP address and a GTP Tunnel Endpoint Identifier (TEID). Illustratively, the downlink tunnel information of the second DU may include a first IP address, where the first IP address is an IP address used when the second DU communicates with the CU-UPF network element.

In a possible embodiment, the second CU-CP of the second RAN may further obtain authentication information from the SMF network element, and the second CU-CP of the second RAN may send the authentication information to the second DU, so that the user plane packet sent by the second DU to the CU-UPF network element may also carry the authentication information, so that the CU-UPF network element may confirm whether the second DU has the right to request to establish the first F1 user plane connection.

And step 1203, the CU-UPF network element establishes a first F1 user plane connection between the CU-UPF network element and the second DU according to the downlink tunnel information of the second DU side and the downlink tunnel information of the CU-UPF network element.

The downlink tunnel information of the CU-UPF network element may include at least one of an IP address and a GTP Tunnel Endpoint Identifier (TEID). Illustratively, the downlink tunnel information of the CU-UPF network element may include a second IP address, where the second IP address is an IP address used when the CU-UPF network element side communicates with the CU-UPF network element through the first DU.

In one possible implementation, the method may further include: and the second DU acquires the uplink tunnel information of the CU-UPF network element from the CU-UPF network element through the second CU-CP, and establishes uplink user plane connection between the second DU and the CU-UPF network element according to the uplink tunnel information of the CU-UPF network element and the uplink tunnel information of the target DU, so that the second DU can receive uplink data from the terminal equipment through the uplink user plane connection.

In the embodiment of the present application, when a DU of a RAN to which a terminal device is accessed is switched, a second CU-CP may authorize a user plane data packet of the second DU to which the terminal device needs to be switched to have a right to send control plane data, so that downlink tunnel information may be sent to a CU-UPF network element by using the user plane data packet, thereby completing updating of a user plane context between the second DU and the CU-UPF network element that are accessed after the terminal device is switched, which may avoid performing reconstruction of an F1 user plane context between the second DU and the CU-UPF network element, thereby reducing a switching delay, and improving problems of large service delay and large signaling overhead caused by reconstruction of an F1 interface.

In fig. 13A, the embodiment of the present application further exemplifies the above communication method by taking a UE switching from a first gNB-DU connected to a first gNB to a second gNB-DU of a second gNB. It should be noted that the first gbb is a source gbb accessed before the terminal is switched, the second gbb is a target gbb accessed after the terminal is switched, the first gbb-DU is a distributed unit of the source gbb, the second gbb-DU is a distributed unit of the target gbb, the first gbb-CU-CP is a control plane entity of the source gbb, and the second gbb-CU-CP is a control plane entity of the target gbb.

Optionally, in step 1300, during the PDU session establishment process, the SMF network element sends, to the gNB-CU-CP of the gNB through the AMF network element, verification information, where the verification information may include a Token (Token), and the verification information is used by the CU-UPF network element to determine an authority of the second gNB-DU, for example, to determine whether the second gNB-DU has an authority to acquire uplink tunnel information of the CU-UPF network element, or to determine whether the second gNB-DU has an authority to modify a user plane context of the CU-UPF network element, or to determine whether the second gNB-DU has an authority to modify an F1 interface of the CU-UPF network element, by the CU-UPF network element.

From step 1301 to step 1302, the UE sends a measurement report to the gNB-CU-CP of the first gNB via the gNB-DU of the first gNB.

The first gNB-DU is a source gNB-DU connected before the UE is switched, the measurement report can comprise information such as received signal power of surrounding gNB-DUs measured by the UE, the UE sends the measurement report to the first gNB-CU-CP, and the gNB-CU-CP determines whether the UE needs to switch the gNB-DU.

And a step 1303, when the first gNB-CU-CP determines that the UE needs to switch the gNB-DU according to the measurement report, the first gNB-CU-CP sends a switching request to the second gNB-CU-CP, and the switching request is used for requesting the terminal equipment to switch to the second gNB-DU of the second gNB-CU-CP.

And step 1304, when the second gNB-CU-CP determines that the UE needs to be switched to a second gNB-DU, the second gNB-CU-CP sends the uplink tunnel information of the CU-UPF network element to the second gNB-DU, and in addition, sends a request to the second gNB-DU, wherein the request is used for requesting the downlink tunnel information of the second gNB-DU, and the downlink tunnel information of the second gNB-DU is used for establishing F1 downlink user plane connection.

And step 1305, after the second gNB-DU receives the uplink tunnel information of the CU-UPF network element, establishing F1 uplink user plane connection between the second gNB-DU and the CU-UPF network element according to the uplink tunnel information of the CU-UPF network element and the uplink tunnel information of the second gNB-DU, so that the second gNB-DU can receive the uplink data of the terminal equipment. And in addition, the second gNB-DU sends a response to the second gNB-CU-CP, and the response comprises the completion of the establishment of the F1 uplink user plane connection.

In step 1306, the second gNB-CU-CP sends a handover command to the first gNB-DU, wherein the handover command is used for instructing the UE to switch from connecting with the first gNB-DU to connecting with the second gNB-DU.

In step 1307 and step 1308, the first gNB-CU-CP sends a handover command to the first gNB-DU, wherein the handover command is used for instructing the UE to switch from connecting the first gNB-DU to connecting the second gNB-DU.

Step 1309, the first gNB-DU sends a Downlink Data Delivery Status message to the CU-UPF network element, which is used to report the Data transmission situation and instruct the CU-UPF to stop sending Downlink Data to the CU-UPF network element.

In step 1310, the first gNB-DU transmits a handover result to the first gNB-CU-CP, wherein the handover result is used for indicating that the first gNB-DU has interrupted the radio connection with the UE and indicating that the first gNB-CU-CP stops transmitting data to the first gNB-CU-CP.

And step 1311, the UE disconnects with the first gNB-DU, and establishes connection with the second gNB-DU through the random access process.

Step 1312, the second gNB-DU sends a user plane Data packet carrying the Downlink tunnel information, such as a user plane Data packet, e.g., a Downlink Data Delivery Status message, to the CU-UPF network element, where the user plane Data packet includes the Downlink tunnel information of the second gNB-DU.

In a possible embodiment, the user plane packet may further include authentication information, and when the authentication information is included in step 1312, the method embodiment may further include the following step 1313.

In step 1313, the CU-UPF network element verifies the second gNB-CU right according to the verification information. For example, the CU-UPF network element determines from the Token (Token) whether the second gNB-CU has the right to modify the F1 user plane connection. If so, the CU-UPF network element performs step 1314, otherwise, step 1314 is not performed.

And step 1314, the CU-UPF network element sends the downlink data of the UE to the second gNB-CU after the verification is passed.

And 1315, the CU-UPF network element modifies the F1 user plane context information between the second gNB-DU and the CU-UPF network element, and reports the modified F1 user plane context information to the SMF network element.

In step 1316, the smf network element feeds back a BEARER CONTEXT MODIFICATION RESPONSE (BEARER CONTEXT MODIFICATION RESPONSE) to the CU-UPF network element through the N4 message, where the BEARER CONTEXT MODIFICATION RESPONSE includes completion of MODIFICATION of the F1 user plane CONTEXT information.

In step 1317 and step 1318, the ue transmits an RRC Reconfiguration Complete message for reporting that the radio connection with the second gNB-DU has been established to the gNB-CU-CP through the second gNB-DU.

In step 1319, the second gNB-CU-CP instructs the first gNB-CU-CP to release the context information of the UE.

Step 1320 and step 1321, the first gNB-CU-CP instructs the first gNB-DU to release the context information of the UE, and the first gNB-DU feeds back a context release completion message of the UE to the first gNB-CU-CP.

And step 1322, the second gNB-CU-CP reports the updated context information of the UE to the AMF network element, wherein the updated context information of the UE comprises the information of the second gNB-CU-CP serving the UE.

Referring to fig. 13B, in this embodiment, a core network element may enable a user plane data packet sent by a second DU to a CU-UPF network element to carry downlink tunnel information of the second DU by authorizing user plane data, so that in a gNB-DU handover process, a downlink user plane connection between the CU-UPF network element and the second gNB-DU is modified first, and finally, a modified user plane context is reported to an SMF network element for synchronization, thereby ensuring fast handover of the gNB-DU.

For the first to fourth embodiments, it should be noted that: (1) The first embodiment and the fourth embodiment may be implemented separately in different scenarios, or may be implemented in the same scenario in combination, or different schemes involved in different embodiments may be implemented in combination (for example, some or all of the schemes involved in the first embodiment may be implemented in combination with the third embodiment), which is not limited specifically.

(2) The step number of each flowchart described in this embodiment of the present application is only one example of an execution flow, and does not limit the execution sequence of the steps, and there is no strict execution sequence between steps that have no time sequence dependency relationship between them in this embodiment of the present application.

The above-mentioned scheme provided by the embodiment of the present application is introduced mainly from the perspective of interaction between a network device and a terminal device. It is understood that, in order to implement the above functions, the network device or the terminal device may include a corresponding hardware structure and/or software module for performing each function. Those of skill in the art will readily appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as hardware or combinations of hardware and computer software. Whether a function is performed as hardware or computer software drives hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the embodiment of the present application, the terminal device and the network device may be divided into the functional units according to the above method examples, for example, each functional unit may be divided corresponding to each function, or two or more functions may be integrated into one unit. The integrated unit may be implemented in the form of hardware, or may also be implemented in the form of a software functional unit.

In case of integrated units, fig. 14 shows a possible exemplary block diagram of the apparatus involved in the embodiments of the present application. As shown in fig. 14, the apparatus 1400 may include: a processing unit 1402 and a communication unit 1403. The processing unit 1402 is used for controlling and managing operations of the apparatus 1400. A communication unit 1403 is used to support the apparatus 1400 in communication with other devices. Optionally, the communication unit 1403 is also referred to as a transceiving unit and may comprise a receiving unit and/or a transmitting unit for performing receiving and transmitting operations, respectively. The apparatus 1400 may also include a storage unit 1401 for storing program code and/or data for the apparatus 1400.

The apparatus 1400 may be a radio access network device (such as a control plane entity or a distributed unit of the RAN) in any of the above embodiments, or may also be a chip disposed in the radio access network device. Processing unit 1402 may enable apparatus 1400 to perform the actions of the radio access network device in the above various method examples. Alternatively, the processing unit 1402 mainly performs internal actions of the radio access network device in the method example, and the communication unit 1403 may support communication between the apparatus 1400 and the radio access network device.

The apparatus 1400 may be a CU-UPF network element in any of the above embodiments, or may also be a chip configured in the CU-UPF network element. The processing unit 1402 may enable the apparatus 1400 to perform the actions of the CU-UPF network element in the above various method examples. Alternatively, the processing unit 1402 essentially performs the internal actions of the CU-UPF network element in the method example, and the communication unit 1403 may support communication between the device 1400 and the CU-UPF network element. For example, processing unit 1402 may be used to perform internal actions of the CU-UPF network element in the method example; the communication unit 1403 may be used to perform the transceiving actions of the CU-UPF network element in the method example.

It should be understood that the division of the units in the above apparatus is only a division of logical functions, and the actual implementation may be wholly or partially integrated into one physical entity or may be physically separated. And the units in the device can be realized in the form of software called by the processing element; or may be implemented entirely in hardware; part of the units can also be realized in the form of software called by a processing element, and part of the units can be realized in the form of hardware. For example, each unit may be a processing element separately set up, or may be implemented by being integrated into a chip of the apparatus, or may be stored in a memory in the form of a program, and a function of the unit may be called and executed by a processing element of the apparatus. In addition, all or part of the units can be integrated together or can be independently realized. The processing element described herein may in turn be a processor, which may be an integrated circuit having signal processing capabilities. In implementation, each step of the above method or each unit above may be implemented by an integrated logic circuit of hardware in a processor element or in a form called by software through the processor element.

In one example, the units in any of the above apparatuses may be one or more integrated circuits configured to implement the above methods, such as: one or more Application Specific Integrated Circuits (ASICs), or one or more microprocessors (DSPs), or one or more Field Programmable Gate Arrays (FPGAs), or a combination of at least two of these Integrated Circuit formats. For another example, when a unit in a device may be implemented in the form of a processing element scheduler, the processing element may be a processor, such as a Central Processing Unit (CPU), or other processor capable of invoking a program. As another example, these units may be integrated together and implemented in the form of a system-on-a-chip (SOC).

The above unit for receiving is an interface circuit of the apparatus for receiving signals from other apparatuses. For example, when the device is implemented in the form of a chip, the receiving unit is an interface circuit for the chip to receive signals from other chips or devices. The above unit for transmitting is an interface circuit of the apparatus for transmitting a signal to other apparatuses. For example, when the device is implemented in the form of a chip, the transmitting unit is an interface circuit for the chip to transmit signals to other chips or devices.

Please refer to fig. 15, which is a schematic structural diagram of a radio access network device according to an embodiment of the present application. It may be the terminal device in the above embodiment, for implementing the operation of the terminal device in the above embodiment. As shown in fig. 15, the radio access network device includes: an antenna 1510, a radio frequency part 1520, a signal processing part 1530. The antenna 1510 is connected to the radio frequency section 1520. In the downlink direction, the radio frequency part 1520 receives information transmitted from the radio access network device through the antenna 1510, and transmits the information transmitted from the radio access network device to the signal processing part 1530 for processing. In the uplink direction, the signal processing part 1530 processes the information of the terminal device and sends the information to the radio frequency part 1520, and the radio frequency part 1520 processes the information of the terminal device and then sends the information to the core network device through the antenna 1510.

The signal processing part 1530 may include a modem subsystem for implementing processing of each communication protocol layer of data; the system also comprises a central processing subsystem used for realizing the processing of the operating system and the application layer of the terminal equipment.

The modem subsystem may include one or more processing elements 1531, including, for example, a main control CPU and other integrated circuits. The modem subsystem may also include a memory element 1532 and an interface circuit 1533. The storage element 1532 is used to store data and programs, but the programs for executing the methods executed by the terminal device in the above methods may not be stored in the storage element 1532, but stored in a memory outside the modem subsystem, and the modem subsystem is loaded for use when in use. The interface circuit 1533 is used to communicate with other subsystems.

The modem subsystem may be implemented by a chip comprising at least one processing element for performing the steps of any of the methods performed by the above radio access network apparatus and interface circuitry for communicating with other devices. In one implementation, the unit of the radio access network device for implementing the steps in the above method may be implemented in the form of a processing element scheduler, for example, an apparatus for the radio access network device includes a processing element and a storage element, and the processing element calls a program stored in the storage element to execute the method executed by the terminal device in the above method embodiment. The memory elements may be memory elements with the processing elements on the same chip, i.e. on-chip memory elements.

In another implementation, the program for performing the method performed by the radio access network device of the above methods may be a memory element on a different chip than the processing element, i.e. an off-chip memory element. At this time, the processing element calls or loads a program from the off-chip storage element onto the on-chip storage element to call and execute the method performed by the radio access network device in the above method embodiment.

In yet another implementation, the unit of the radio access network device implementing the steps of the above method may be configured as one or more processing elements disposed on the modem subsystem, where the processing elements may be integrated circuits, for example: one or more ASICs, or one or more DSPs, or one or more FPGAs, or a combination of these types of integrated circuits. These integrated circuits may be integrated together to form a chip.

The units of the radio access network device for implementing the steps of the above method can be integrated together and implemented in the form of an SOC chip for implementing the above method. At least one processing element and a storage element can be integrated in the chip, and the processing element calls the stored program of the storage element to realize the method executed by the wireless access network equipment; alternatively, at least one integrated circuit may be integrated in the chip, for implementing the method performed by the above radio access network device; alternatively, the above implementation modes may be combined, the functions of the partial units are implemented in the form of a processing element calling program, and the functions of the partial units are implemented in the form of an integrated circuit.

It can be seen that the above apparatus for a radio access network device may comprise at least one processing element and interface circuitry, wherein the at least one processing element is configured to perform the method performed by any one of the radio access network devices provided by the above method embodiments. The processing element may: namely, the method calls the program stored in the memory element to execute part or all of the steps executed by the wireless access network equipment; it is also possible to: that is, some or all of the steps performed by the terminal device are performed by integrated logic circuits of hardware in the processor element in combination with the instructions; of course, some or all of the steps performed by the terminal device may be performed in combination with the first manner and the second manner.

The processing elements herein, like those described above, may be implemented by a processor, and the functions of the processing elements may be the same as those of the processing unit described in fig. 14. Illustratively, the processing element may be a general-purpose processor, such as a CPU, and may also be one or more integrated circuits configured to implement the above methods, such as: one or more ASICs, or one or more microprocessors DSP, or one or more FPGAs, etc., or a combination of at least two of these integrated circuit forms. The memory elements may be implemented by memory, and the function of the memory elements may be the same as that of the memory cells described in fig. 14. The memory elements may be implemented by memory, and the function of the memory elements may be the same as that of the memory cells described in fig. 14. The storage element may be a single memory or a combination of memories.

The radio access network device shown in fig. 15 can implement the processes related to the radio access network device in the method embodiments illustrated in fig. 6, 7A, 8, 9A, 10, 11A, 12 and 13A. The operations and/or functions of the respective modules in the radio access network device shown in fig. 15 are respectively for implementing the corresponding flows in the above-described method embodiments. Specifically, reference may be made to the description of the above method embodiments, and the detailed description is appropriately omitted herein to avoid redundancy.

Please refer to fig. 16, which is a schematic structural diagram of a CU-UPF network element according to an embodiment of the present application. For implementing the operations of the CU-UPF network elements in the above embodiments. As shown in fig. 16, the CU-UPF network element includes: an antenna 1601, a radio frequency device 1602, a baseband device 1603. The antenna 1601 is connected to the radio frequency device 1602. In the uplink direction, the radio frequency device 1602 receives information transmitted by the radio access network device via the antenna 1601, and transmits the information transmitted by the radio access network device to the baseband device 1603 for processing. In the downlink direction, the baseband device 1603 processes the information of the radio access network equipment and transmits the information to the radio frequency device 1602, and the radio frequency device 1602 processes the information of the radio access network equipment and transmits the information to the radio access network equipment through the antenna 1601.

The baseband device 1603 may include one or more processing elements 16031, for example, including a master CPU and other integrated circuits. In addition, the baseband device 1603 may further include a storage component 16032 and an interface 16033, the storage component 16032 is used for storing programs and data; the interface 16033 is used for exchanging information with the radio frequency device 1602, and is, for example, a Common Public Radio Interface (CPRI). The above means for the CU-UPF network element may be located on the baseband device 1603, for example, the above means for the CU-UPF network element may be a chip on the baseband device 1603, the chip comprising at least one processing element for performing the respective steps of any one of the methods performed by the above CU-UPF network element and interface circuitry for communicating with other devices. In one implementation, the unit for implementing each step in the above method by the CU-UPF network element may be implemented in the form of a processing element scheduler, for example, an apparatus for the CU-UPF network element includes a processing element and a storage element, and the processing element calls the program stored in the storage element to execute the method executed by the CU-UPF network element in the above method embodiment. The memory elements may be memory elements on the same chip as the processing element, i.e. on-chip memory elements, or may be memory elements on a different chip than the processing element, i.e. off-chip memory elements.

In another implementation, the unit of the CU-UPF network element implementing the steps of the above method may be configured as one or more processing elements disposed on the baseband device, where the processing elements may be integrated circuits, such as: one or more ASICs, or one or more DSPs, or one or more FPGAs, or a combination of these types of integrated circuits. These integrated circuits may be integrated together to form a chip.

The units of the CU-UPF network element implementing the steps of the above method may be integrated together and implemented in the form of a system-on-a-chip (SOC), for example, a baseband device including the SOC chip for implementing the above method. At least one processing element and a storage element can be integrated in the chip, and the processing element calls the stored program of the storage element to realize the method executed by the CU-UPF network element; or, at least one integrated circuit can be integrated in the chip for implementing the method executed by the CU-UPF network element; alternatively, the above implementation modes may be combined, the functions of the partial units are implemented in the form of a processing element calling program, and the functions of the partial units are implemented in the form of an integrated circuit.

It can be seen that the above apparatus for a CU-UPF network element may comprise at least one processing element and an interface circuit, wherein the at least one processing element is configured to perform any one of the methods performed by the CU-UPF network element provided by the above method embodiments. The processing element may: namely, calling a program stored in a storage element to execute part or all of the steps executed by the CU-UPF network element; it is also possible to: that is, some or all of the steps performed by the CU-UPF network element are performed by integrated logic circuits of hardware in the processor element in combination with instructions; of course, some or all of the steps performed by the above CU-UPF network element may also be performed in combination with the first and second ways.

The CU-UPF network element shown in fig. 16 is capable of implementing the various processes involving the CU-UPF network element in the above-described method embodiments. The operations and/or functions of the respective modules in the CU-UPF network element shown in fig. 16 are respectively for implementing the corresponding flows in the above-described method embodiments. Specifically, reference may be made to the description of the above method embodiments, and the detailed description is appropriately omitted herein to avoid redundancy.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

Claims

1. A method of communication, the method comprising:

a control plane entity CU-CP of the radio access network equipment receives control port information from a core network element, a control port indicated by the control port information corresponds to a protocol data unit PDU session and is a control port of a CU-UPF network element, and the CU-UPF network element consists of a user plane entity CU-UP corresponding to a centralized unit CU of the radio access network equipment and a user plane function UPF network element;

when a terminal device is switched from a source Distributed Unit (DU) of the wireless access network device to a target DU of the wireless access network device, the CU-CP acquires downlink tunnel information of the target DU for establishing a first F1 user plane connection from the target DU; wherein the first F1 user plane connection is a downlink user plane connection between the target DU and the CU-UPF network element;

the CU-CP sends the downlink tunnel information to the CU-UPF network element through the control port;

wherein the downlink tunnel information is used for establishing the first F1 user plane connection.

2. The method of claim 1, further comprising:

the CU-CP acquires uplink tunnel information from the CU-UPF network element through the control port, wherein the uplink tunnel information is the uplink tunnel information connected with a second F1 user plane between the CU-UPF network element and the source DU;

the CU-CP sends the uplink tunnel information to the target DU, wherein the uplink tunnel information is used for establishing uplink user plane connection between the target DU and the CU-UPF network element;

wherein the uplink tunnel information and the downlink tunnel information include at least one of an internet protocol, IP, address and a tunnel endpoint identification.

3. The method of claim 2, further comprising:

the CU-CP receives verification information from the core network element;

the CU-CP sends the verification information to the CU-UPF network element through the control port;

the verification information is used for determining the authority of the CU-CP for acquiring the uplink tunnel information.

4. A method of communication, comprising:

when a terminal device is switched from a source Distributed Unit (DU) of a wireless access network device to a target DU of the wireless access network device, a CU-UPF network element receives a second message from a control plane entity CU-CP of the wireless access network device through a control port; wherein, the second message includes downlink tunnel information of the target DU, the CU-UPF element is composed of a user plane entity CU-UP and a user plane function UPF element corresponding to a centralized unit CU of the radio access network device, and the control port is a control port of the CU-UPF element that is allocated by a core network element to the CU-UPF element and corresponds to a protocol data unit PDU session;

the CU-UPF network element establishes a first F1 user plane connection according to the downlink tunnel information and the downlink tunnel information of the CU-UPF network element;

wherein the first F1 user plane connection is a downlink user plane connection between the target DU and the CU-UPF network element.

5. The method of claim 4, further comprising:

the CU-UPF network element receives a request message from the CU-CP through the control port, wherein the request message is used for requesting uplink tunnel information, and the uplink tunnel information is the uplink tunnel information connected with a second F1 user plane between the CU-UPF network element and the source DU;

the CU-UPF network element sends the uplink tunnel information to the CU-CP through the control port, wherein the uplink tunnel information is used for establishing uplink user plane connection between the target DU and the CU-UPF network element;

wherein the uplink tunnel information and the downlink tunnel information include at least one of an internet protocol IP address and a tunnel endpoint identification.

6. The method of claim 5, further comprising:

the CU-UPF network element receives verification information from the CU-CP through the control port;

and the CU-UPF network element determines the authority of the CU-CP for acquiring the uplink tunnel information according to the verification information.

7. The method of claim 5 or 6, further comprising:

and the CU-UPF network element sends the downlink tunnel information of the target DU, and the uplink tunnel information and the downlink tunnel information of the CU-UPF network element to the core network element.

8. A method of communication, comprising:

a target distributed unit DU of a wireless access network device receives first information from a core network element through a control plane entity CU-CP of the wireless access network device;

when a terminal device is switched from a source DU to a target DU of the wireless access network device, the target DU sends a user plane data packet carrying downlink tunnel information of the target DU to a CU-UPF network element according to the first information, wherein the downlink tunnel information is used for establishing a first F1 user plane connection;

wherein the first F1 user plane connection is a downlink user plane connection between the target DU and the CU-UPF network element, and the CU-UPF network element is composed of a user plane entity CU-UP corresponding to a centralized unit CU of the radio access network device and a user plane function UPF network element.

9. The method of claim 8, further comprising:

the target DU receives uplink tunnel information from a CU-UPF network element through the CU-CP, wherein the uplink tunnel information is uplink tunnel information connected with a second F1 user plane between the CU-UPF network element and the source DU;

the target DU establishes uplink user plane connection between the target DU and the CU-UPF network element according to the uplink tunnel information and the uplink tunnel information of the target DU;

10. The method of claim 9, wherein the user plane packet further comprises authentication information; the verification information is used for determining the authority of the target DU to acquire the uplink tunnel information.

11. A method of communication, comprising:

when a terminal device is switched from a source Distributed Unit (DU) of a wireless access network device to a target DU of the wireless access network device, a CU-UPF network element receives a user plane data packet from the target DU, wherein the user plane data packet carries downlink tunnel information of the target DU, and the CU-UPF network element consists of a user plane entity CU-UP and a user plane function UPF network element, wherein the user plane entity CU-UP corresponds to a centralized unit CU of the wireless access network device;

12. The method of claim 11, further comprising:

the CU-UPF network element sends uplink tunnel information to the target DU through the CU-CP;

wherein the uplink tunnel information is uplink tunnel information of a second F1 user plane connection between the CU-UPF network element and the source DU, and the uplink tunnel information is used for establishing an uplink user plane connection between the target DU and the CU-UPF network element; the uplink tunnel information and the downlink tunnel information include at least one of an internet protocol, IP, address and a tunnel endpoint identification.

13. The method of claim 12, further comprising:

the CU-UPF network element receives verification information from the target DU;

the verification information is used for determining the authority of the target DU to acquire the uplink tunnel information.

14. A method of communication, the method comprising:

a target control plane entity CU-CP of the target radio access network equipment receives control port information from a core network element through a source CU-CP of the source radio access network equipment, a control port indicated by the control port information corresponds to a protocol data unit PDU session and is a control port of a CU-UPF network element, and the CU-UPF network element consists of a user plane entity CU-UP corresponding to a centralized unit CU of the target radio access network equipment and a user plane function UPF network element;

when terminal equipment is switched from a source DU of the source wireless access network equipment to a target DU of the target wireless access network equipment, the target CU-CP acquires downlink tunnel information of the target DU for establishing first F1 user plane connection from the target DU; wherein the first F1 user plane connection is a downlink user plane connection between the target DU and the CU-UPF network element;

the target CU-CP sends the downlink tunnel information to the CU-UPF network element through the control port;

15. The method of claim 14, further comprising:

the target CU-CP acquires uplink tunnel information from the CU-UPF network element through the control port; the uplink tunnel information is the uplink tunnel information of the second F1 user plane connection between the CU-UPF network element and the source DU;

the target CU-CP sends the uplink tunnel information to the target DU, and the uplink tunnel information is used for establishing uplink user plane connection between the target DU and the CU-UPF network element;

16. The method of claim 15, further comprising:

the target CU-CP receives verification information from the core network element;

the target CU-CP sends the verification information to the CU-UPF network element through the control port;

wherein the verification information is used for determining the authority of the target CU-CP to acquire the uplink tunnel information.

17. The method according to any one of claims 14 to 16, comprising:

the target CU-CP updating the context information of the terminal equipment, wherein the context information of the terminal equipment comprises the information of the target wireless access network equipment serving the terminal equipment;

and the target CU-CP sends the updated context information of the terminal equipment to the network element of the core network.

18. A method of communication, the method comprising:

when the terminal equipment is switched from a source distributed unit DU of source wireless access network equipment to a target DU of target access network equipment, a CU-UPF network element receives a second message of a target CU-CP from the target wireless access network equipment through a control port; the second message comprises downlink tunnel information of the target DU, the CU-UPF network element consists of a user plane entity CU-UP and a user plane function UPF network element which correspond to a centralized unit CU of the target radio access network equipment, and the control port is a control port of the CU-UPF network element which is allocated by the core network element for the CU-UPF network element and corresponds to a protocol data unit PDU session;

the CU-UPF network element establishes a first F1 user plane connection according to the downlink tunnel information of the target DU and the downlink tunnel information of the CU-UPF network element;

19. The method of claim 18, further comprising:

the CU-UPF network element receives a request message from the CU-CP through the control port, wherein the request message is used for requesting uplink tunnel information, and the uplink tunnel information is uplink tunnel information connected with a second F1 user plane between the CU-UPF network element and the source DU;

the CU-UPF network element sends the uplink tunnel information to the target CU-CP through the control port, wherein the uplink tunnel information is used for establishing uplink user plane connection between the target DU and the CU-UPF network element;

20. The method of claim 19, further comprising:

the CU-UPF network element receives verification information from the target CU-CP through the control port:

and the CU-UPF network element determines the authority of the target CU-CP for acquiring the uplink tunnel information according to the verification information.

21. The method of claim 19 or 20, further comprising:

22. A method of communication, the method comprising:

a target distributed unit DU of a target wireless access network device receives first information from a source CU-CP of a source wireless access network device through a target CU-CP of the target wireless access network device;

when a terminal device is switched from a source DU of the source wireless access network device to be connected with the target DU, the target DU sends a user plane data packet carrying downlink tunnel information of the target DU to a CU-UPF network element according to the first information, wherein the downlink tunnel information is used for establishing a first F1 user plane connection;

wherein the first F1 user plane connection is a downlink user plane connection between the target DU and the CU-UPF network element, and the CU-UPF network element is composed of a user plane entity CU-UP and a user plane function UPF network element corresponding to a centralized unit CU of the target radio access network device.

23. The method of claim 22, further comprising:

the target DU acquires uplink tunnel information from the CU-UPF through the target CU-CP, wherein the uplink tunnel information is uplink tunnel information connected with a second F1 user plane between the CU-UPF network element and the source DU;

24. The method of claim 23, wherein the user plane packet further comprises authentication information; the verification information is used for determining the authority of the target DU to acquire the uplink tunnel information.

25. A method of communication, comprising:

when a terminal device is switched from a source distributed unit DU of a source wireless access network device to a target DU of a target wireless access network device, a CU-UPF network element receives a user plane data packet of the target DU from the target wireless access network device, wherein the user plane data packet carries downlink tunnel information of the target DU, and the CU-UPF network element consists of a user plane entity CU-UP corresponding to a centralized unit CU of the target wireless access network device and a user plane function UPF network element;

26. The method of claim 25, further comprising:

the CU-UPF network element sends uplink tunnel information to the target DU through the target CU-CP;

the uplink tunnel information is uplink tunnel information of a second F1 user plane connection between the CU-UPF network element and the source DU, the uplink tunnel information is used for establishing an uplink user plane connection between the target DU and the CU-UPF network element, and the uplink tunnel information and the downlink tunnel information include at least one of an internet protocol IP address and a tunnel endpoint identifier.

27. The method of claim 26, further comprising:

28. A communication system comprising a target distributed unit, DU, of a radio access network device and a CU-UPF network element consisting of a user plane entity, CU-UP, and a user plane function, UPF, network element corresponding to a centralized unit, CU, of said radio access network device;

the target DU is used for receiving first information from a core network element through a control plane entity CU-CP of the radio access network equipment; when the terminal equipment is switched from a source Distributed Unit (DU) of the wireless access network equipment to a target DU of the wireless access network equipment, sending a user plane data packet carrying downlink tunnel information of the target DU to a CU-UPF network element according to the first information;

the CU-UPF network element is used for receiving the user plane data packet and establishing a first F1 user plane connection according to the downlink tunnel information and the downlink tunnel information of the CU-UPF network element;

29. The system according to claim 28, wherein said CU-UPF network element is further configured to send uplink tunnel information to said target DU through said CU-CP;

the target DU is further configured to receive the uplink tunnel information, and establish an uplink user plane connection between the target DU and the CU-UPF network element according to the uplink tunnel information and the uplink tunnel information of the target DU;

the uplink tunnel information is uplink tunnel information of a second F1 user plane connection between the CU-UPF network element and the source DU, and the uplink tunnel information and the downlink tunnel information include at least one of an internet protocol IP address and a tunnel endpoint identifier.

30. The system according to claim 29, wherein said CU-UPF network element is further configured to receive authentication information from said target DU;

31. A communications device comprising at least one processor coupled to a memory, the at least one processor configured to read and execute a program stored in the memory to cause the device to perform the method of any of claims 1-3 or 14-17.

32. A communications apparatus comprising at least one processor coupled to a memory, the at least one processor configured to read and execute a program stored in the memory to cause the apparatus to perform the method of any of claims 4-7, 11-13, 18-21 or 25-27.

33. A communications device comprising at least one processor coupled to a memory, the at least one processor configured to read and execute a program stored in the memory to cause the device to perform the method of any of claims 8-10, 22-24.

34. A chip coupled to a memory for reading and executing program instructions stored in the memory to implement the method of any one of claims 1-27.

35. A communication system, comprising: a control plane entity CU-CP of a radio access network device performing the method according to any of claims 1 to 3 and a CU-UPF network element performing the method according to any of claims 4 to 7.

36. A communication system, comprising: a target distributed unit, DU, of a radio access network device performing the method according to any of claims 8-10 and a CU-UPF network element performing the method according to any of claims 11-13.

37. A communication system, comprising: a target radio access network device target control plane entity CU-CP performing the method of any of claims 14-17 and a CU-UPF network element performing the method of any of claims 18-21.

38. A communication system, comprising: a target distributed unit, DU, of a target radio access network device performing the method according to any of claims 22-24 and a CU-UPF network element performing the method according to any of claims 25-27.

39. A computer-readable storage medium having stored thereon computer instructions which, when executed on a computer, cause the computer to perform the method of any one of claims 1-27.