Switching method and device, network equipment, storage medium and program product

Abstract

Disclosed are a switching method and apparatus, a network device, a storage medium and a program product, the method comprising: after receiving a switching request message sent by a second control unit, a first control unit sends a UE context establishment request message to a first user unit; the first control unit receives a UE context establishment response message sent by the first user unit, wherein the UE context establishment response message carries a first TNL address; the first TNL address is used for data forward transmission between a second user unit and the first user unit; thus, by carrying the TNL address in the UE context management signaling, the data plane time delay in the switching process is reduced, and the switching success rate is improved.

Description

Technical Field

[0001] This application relates to the field of wireless communication technology, and in particular to a switching method and apparatus, network equipment, computer-readable storage medium and program product. Background Technology

[0002] A crucial process in wireless mobile communication systems is handover, a technical means of mobile communication. To ensure reliable and low-latency handover, the 3rd Generation Partnership Project (3GPP) has discussed various handover enhancement schemes, such as Conditional Handover (CHO), Dual Active Protocol Stack (DAPS), and L1 / L2 Triggered Mobility (LTM) schemes that allow changes to multiple candidate cells (or cell groups) via Layer 1 (L1) or Layer 2 (L2) signaling control terminals. The challenge of mobile wireless networks lies in improving handover performance and success rate while reducing handover failures and reconstruction events. Therefore, an effective handover method is urgently needed to address this issue. Summary of the Invention

[0003] To address the aforementioned technical problems, embodiments of the present invention provide a switching method and apparatus, a network device, a computer-readable storage medium, and a program product.

[0004] Firstly, the switching method provided in the embodiments of this application includes:

[0005] After receiving the handover request message sent by the second control unit, the first control unit sends a UE context establishment request message to the first user unit;

[0006] The first control unit receives a User Equipment (UE) context establishment response message sent by the first user unit. The UE context establishment response message carries a first Transport Network Layer (TNL) address. The first TNL address is used for data fronthaul between the second user unit and the first user unit.

[0007] Secondly, the switching method provided in the embodiments of this application includes:

[0008] After the second control unit sends a handover request message to the first control unit, it receives a handover request confirmation message sent by the first control unit. The handover request confirmation message carries a first TNL address. The first TNL address is used for data forwarding between the second user unit and the first user unit.

[0009] The second control unit sends a UE context modification request message to the second user unit, the UE context modification request message carrying the first TNL address.

[0010] Thirdly, the switching method provided in the embodiments of this application includes:

[0011] After receiving the UE context establishment request message sent by the first control unit, the first user unit sends a UE context establishment response message to the first control unit. The UE context establishment response message carries a first TNL address. The first TNL address is used for data fronthaul between the second user unit and the first user unit.

[0012] Fourthly, the switching method provided in the embodiments of this application includes:

[0013] The second user unit receives a UE context modification request message sent by the second control unit. The UE context modification request message carries a first TNL address. The first TNL address is used for data fronthaul between the second user unit and the first user unit.

[0014] Fifthly, the switching device provided in the embodiments of this application is applied to a first control unit and includes:

[0015] The receiving unit is used to receive the switching request message sent by the second control unit;

[0016] The sending unit is used to send a UE context establishment request message to the first user unit;

[0017] The receiving unit is further configured to receive a UE context establishment response message sent by the first user unit, the UE context establishment response message carrying a first TNL address; the first TNL address is used for data forwarding between the second user unit and the first user unit.

[0018] Sixthly, the switching device provided in the embodiments of this application is applied to a second control unit and includes:

[0019] The sending unit is used to send a handover request message to the first control unit;

[0020] The receiving unit is configured to receive a handover request confirmation message sent by the first control unit, the handover request confirmation message carrying a first TNL address; the first TNL address is used for data forwarding between the second user unit and the first user unit;

[0021] The sending unit is further configured to send a UE context modification request message to the second user unit, the UE context modification request message carrying the first TNL address.

[0022] Seventhly, the switching device provided in the embodiments of this application is applied to a first user unit and includes:

[0023] The receiving unit is used to receive the UE context establishment request message sent by the first control unit;

[0024] The sending unit is configured to send a UE context establishment response message to the first control unit, the UE context establishment response message carrying a first TNL address; the first TNL address is used for data fronthaul between the second user unit and the first user unit.

[0025] Eighthly, the switching device provided in the embodiments of this application is applied to a second user unit and includes:

[0026] The receiving unit is configured to receive a UE context modification request message sent by the second control unit, the UE context modification request message carrying a first TNL address; the first TNL address is used for data fronthaul between the second user unit and the first user unit.

[0027] Ninthly, the network device provided in the embodiments of this application includes: a processor and a memory, the memory being used to store a computer program, and the processor being used to call and run the computer program stored in the memory to execute any of the above-described switching methods.

[0028] In a tenth aspect, the computer-readable storage medium provided in the embodiments of this application is used to store a computer program that causes a computer to execute any of the above-described switching methods.

[0029] Eleventhly, the computer program product provided in the embodiments of this application includes computer program instructions that cause a computer to execute any of the switching methods described above.

[0030] In the technical solution of this application embodiment, after receiving the handover request message sent by the second control unit, the first control unit sends a UE context establishment request message to the first user unit; the first control unit receives the UE context establishment response message sent by the first user unit, the UE context establishment response message carries a first TNL address, the first TNL address is used for data front-pass between the second user unit and the first user unit; thus, by carrying the TNL address in the UE context management signaling, the data plane latency of the handover process is reduced, thereby improving the handover success rate. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a network architecture provided in an embodiment of this application. Figure 1 ;

[0032] Figure 2 This is a schematic diagram of a data format corresponding to a protocol layer provided in an embodiment of this application. Figure 1 ;

[0033] Figure 3 This is a flowchart illustrating a switching method provided in an embodiment of this application. Figure 1 ;

[0034] Figure 4 This is a flowchart illustrating a switching method provided in an embodiment of this application. Figure 2 ;

[0035] Figure 5 This is a schematic diagram of a network architecture provided in an embodiment of this application. Figure 2 ;

[0036] Figure 6 This is a flowchart illustrating a switching method provided in an embodiment of this application. Figure 3 ;

[0037] Figure 7 This is a schematic diagram of data transmission provided in an embodiment of this application;

[0038] Figure 8a This is a schematic diagram of a data format corresponding to a protocol layer provided in an embodiment of this application. Figure 2 ;

[0039] Figure 8b This is a schematic diagram of a data format corresponding to a protocol layer provided in an embodiment of this application. Figure 3 ;

[0040] Figure 9 This is a flowchart illustrating a switching method provided in an embodiment of this application. Figure 4 ;

[0041] Figure 10 This is a flowchart illustrating a switching method provided in an embodiment of this application.Figure 5 ;

[0042] Figure 11 This is a flowchart illustrating a switching method provided in an embodiment of this application. Figure 6 ;

[0043] Figure 12 This is a flowchart illustrating a switching method provided in an embodiment of this application. Figure 7 ;

[0044] Figure 13 This is a schematic diagram of the structural composition of a switching device provided in an embodiment of this application. Figure 1 ;

[0045] Figure 1 This is a schematic diagram of the structural composition of a switching device provided in an embodiment of this application. Figure 1 ;

[0046] Figure 2 This is a schematic diagram of the structural composition of a switching device provided in an embodiment of this application. Figure 1 ;

[0047] Figure 2 This is a schematic diagram of the structural composition of a switching device provided in an embodiment of this application. Figure 3 ;

[0048] Figure 3 This is a schematic structural diagram of a network device provided in an embodiment of this application. Detailed Implementation

[0049] The technical solutions of the embodiments of this application will now be described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0050] Figure 1 This is a schematic diagram of a network architecture according to an embodiment of this application. Figure 4 .like Figure 2As shown, in New Radio (NR), a DU-CU separation architecture is introduced on the network side, separating the Distributed Unit (DU) and the Centralized Unit (CU). In this architecture, the Service Data Adaptation Protocol (SDAP) and Packet Data Convergence Protocol (PDCP) entities reside in the CU, while the Radio Link Control (RLC), Media Access Control (MAC), and Physical (PHY) entities reside in the DU. The Radio Resource Control (RRC) layer resides in the CU. The F1 interface is used to transmit control signaling and user data between the DU and CU. The F1 interface is divided into a control plane (F1-C) and a user plane (F1-U), where F1-C provides control functions between the DU and CU, and F1-U provides user data transmission functions between the DU and CU. An XN control plane interface (XN-C) and a user plane function interface (XN-U) are defined between two logically connected RAN nodes. Control signaling between RAN nodes is transmitted through XN-C, and user plane data between RAN nodes is transmitted through XN-U.

[0051] Figure 5 This is a schematic diagram of the data format corresponding to the protocol layer provided in the embodiments of this application. Figure 2For a protocol layer, the data received from the upper layer is called a Service Data Unit (SDU). The data generated after processing by this protocol layer and adding the corresponding protocol layer header is called a Protocol Data Unit (PDU). The data processing flow from the user plane is as follows: User plane data first arrives at the SDAP layer via QoS streams. The SDAP layer is responsible for mapping data from different QoS streams to different DRBs and adding QoS stream identifiers to the data according to network configuration, generating SDAP Packet Data Units (SDAP PDUs) and submitting them to the PDCP layer. The PDCP layer performs relevant processing on the SDAP PDUs (also known as PDCPSDUs), including header compression, encryption, and integrity protection, and generates PDCP PDUs which are then submitted to the RLC layer. The RLC layer processes RLC SDUs according to the configured RLC mode, such as RLC SDU segmentation and retransmission management. The MAC layer is responsible for multiplexing the data from the logical channel into a MAC PDU (also called a transport block). This MAC PDU can include segments of multiple RLCSDUs or RLC SDUs. A MAC PDU can contain one or more SDUs. One MAC SDU can correspond to a complete RLC SDU or a segment of an RLC SDU. The higher-layer protocol stack primarily handles data processing, ensuring data transmission according to the Quality of Service (QoS) service type. Specifically, the SDAP layer is responsible for mapping between QoS streams and Data Radio Bearers (DRBs). The PDCP layer handles encryption / decryption, integrity protection, header compression, sequence number (SN) generation, reordering, in-order or out-of-order data delivery, SDU discarding, duplicate discarding, reconstruction, and status report-based retransmission. The RLC layer handles RLC SDU packet segmentation and reassembly, error detection, Automatic Repeat-reQuest (ARQ), sequence number (SN) generation, sorting, duplicate detection, SDU discarding, reconstruction, and status report-based retransmission. However, due to the continuous enhancement and backward compatibility of 5G user plane functions, the concept of the user plane protocol stack layer has become increasingly "thick," resulting in a growing overhead in packet headers. The SDAP protocol layer is too simple, and the PDCP and RLC layers have the same and closely related functional mechanisms, both having retransmission and reordering functions. This makes the protocol stack cumbersome and bloated, leading to redundant deployment issues.

[0052] It should be noted that, Figure 5 andFigure 6 This application merely illustrates the system to which this application applies; of course, the methods shown in the embodiments of this application can also be applied to other systems. Furthermore, the terms "system" and "network" are often used interchangeably herein. The term "and / or" in this application merely describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this application generally indicates that the preceding and following related objects have an "or" relationship. It should also be understood that "instruction" mentioned in the embodiments of this application can be a direct instruction, an indirect instruction, or an indication of a related relationship. For example, A instructing B can mean that A directly instructs B, for example, B can be obtained through A; it can also mean that A indirectly instructs B, for example, A instructs C, B can be obtained through C; or it can mean that there is a related relationship between A and B. It should also be understood that "correspondence" mentioned in the embodiments of this application can indicate a direct or indirect correspondence between two things, or an related relationship between two things, or a relationship of instruction and being instructed, configuration and being configured, etc.

[0053] It should be noted that the terms "first," "second," etc., used herein are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0054] To facilitate understanding of the technical solutions of the embodiments of this application, the relevant technologies of the embodiments of this application are described below. The following relevant technologies are optional solutions and can be combined with the technical solutions of the embodiments of this application in any way, and they all fall within the protection scope of the embodiments of this application.

[0055] A crucial process in wireless mobile communication systems is handover, a technical means of mobile communication. To ensure reliable and low-latency handover, 3GPP has discussed various handover enhancement schemes, such as Conditional Handover (CHO), Dual Active Protocol Stack (DAPS), and LTM (L1 / L2 Triggered Mobility). Here, refer to... Figure 6 , Figure 3 This is a flowchart illustrating the switching method provided in the embodiments of this application. Figure 6This indicates a DAPS-based handover process between devices. DAPS handover is a special handover procedure. When a UE receives an RRC handover message, it maintains a connection with the source gNB until it successfully accesses the target gNB and releases the source cell. After receiving the DAPS handover command, the UE continues to maintain downlink (DL) and uplink (UL) user data connections with the source gNB until the target cell successfully completes Random Access Channel (RACH) (UL handover). Upon receiving the uplink handover indication, the PDCP layer will only forward user data to the target path for uplink transmission. Before releasing the source gNB, the UE will continue to receive downlink data from both the source and target nodes simultaneously and send uplink data to both the source and target nodes (but PDCP will not forward user data to lower layers). If the handover fails and the source link is still valid, the UE can directly use the source link to recover without re-establishing a connection. The specific handover procedure is as follows:

[0056] Step 300: AMF provides mobility control information.

[0057] Step 301: UE performs measurement control, UL assignment, and measurement report.

[0058] Step 302: Source gNB switching decision.

[0059] Step 303: The source gNB sends a handover request to the target gNB.

[0060] Here, the source gNB sends a handover request to the target gNB through the Xn interface.

[0061] Step 304: Target gNB Admission Control.

[0062] Here, the target gNB performs admission control and provides RRC configuration in the handover request confirmation.

[0063] Step 305: The target gNB sends a handover request confirmation message to the source gNB.

[0064] Step 306: RAN handover start.

[0065] Here, the source gNB forwards the RRC reconfiguration message to the UE, thereby providing RRC configuration. The source gNB initiates the handover of the Uu interface by sending the RRC reconfiguration message.

[0066] Step 307a: The source gNB sends an early state transition to the target gNB.

[0067] Here, for a DRB configured with DAPS, the source gNB sends an SN early status transmission message.

[0068] Step 307b: The source gNB sends an SN state transition to the target gNB.

[0069] Here, for a DRB that is not configured with DAPS, the source gNB sends an SN status transfer message to the target gNB.

[0070] Step 308: RAN handover completed.

[0071] Step 308a: The target gNB sends a success message to the source gNB.

[0072] Step 308b: The source gNB sends an SN state transition to the target gNB.

[0073] Here, the UE synchronizes with the target cell and completes the RACH and RRC handover process by sending an RRC reconfiguration complete message to the target gNB. During DAPS handover, the target gNB sends a handover success message to the source gNB, informing the UE that it has successfully accessed the target cell.

[0074] Step 309: The target gNB sends a path switching request to the core network.

[0075] Step 310: UPF path selection.

[0076] Step 311: The core network sends a path switching confirmation message to the target gNB.

[0077] Step 312: The target gNB sends a UE context release message to the source gNB.

[0078] Figure 5 This is a flowchart illustrating the switching method provided in the embodiments of this application. Figure 7 This represents the handover process between network elements based on DAPS. The source gNB-side node includes the source DU, source CUUP, and source CUCP; the target gNB-side node includes the target DU, target CUUP, and target CUCP. The specific handover process is as follows:

[0079] Step 401: The source CUCP sends a handover request message to the target CUCP.

[0080] Step 402: The target CUCP sends a bearer content establishment request message to the target CUUP.

[0081] Step 403: The target CUUP sends a bearer content establishment confirmation message to the target CUCP.

[0082] Step 404: UE context establishment process for establishing F1 interface between target DU and target CUCP.

[0083] Step 405: The target CUCP sends a handover request confirmation message to the source CUCP.

[0084] Step 406: UE context modification process for establishing F1 interface between source DU and source CUCP.

[0085] Step 407: The source CUCP sends a bearer content modification request message to the source CUUP.

[0086] Step 408: The source CUUP sends a bearer content modification confirmation message to the source CUCP.

[0087] Step 409: The source CUCP sends an SN early status transmission message or an SN status transmission message to the target CUCP.

[0088] Step 410: The target CUCP sends a bearer content modification request message to the target CUUP.

[0089] Step 411: The target CUUP sends a bearer content modification confirmation message to the target CUCP.

[0090] Step 412a: The target CUCP sends a handover success message to the source CUCP.

[0091] Step 412b: UE context modification procedure between source CUCP and source DU via F1 interface.

[0092] Step 412c: The source CUCP sends a bearer content modification request message to the source CUCP.

[0093] Step 412d: The source CUCP sends a confirmation message to the source CUUP regarding the modification of the bearer content.

[0094] Step 412e: The source CUCP sends an SN status transmission message to the target CUCP.

[0095] Step 412f: The target CUCP sends a bearer content modification request message to the target CUCP.

[0096] Step 412g: The target CUUP sends a bearer content modification confirmation message to the target CUCP.

[0097] Step 413: Path switching process between the target CUCP and the core network.

[0098] Step 414: The core network sends an end marker message to the source CUUP.

[0099] Step 415: The core network sends a new path to the source CUUP.

[0100] Step 416: The target CUCP sends a UE context release message to the source CUCP.

[0101] Step 417: The source CUCP sends a bearer content release message to the source CUUP.

[0102] Step 418: The source CUCP and source CUUP perform the UE context release procedure via the F1 interface.

[0103] Step 419: The source CUUP sends a message to the source CUCP indicating that the bearer content release is complete.

[0104] The challenge of mobile wireless networks lies in improving handover performance and success rate, and reducing handover failures and reconstruction events. Current handover improvement schemes focus on reducing air interface latency or using dual-activation protocol stacks to achieve reliable and low-latency handover, without adequately considering simplifying signaling procedures to improve handover success rate. Therefore, this application proposes the following technical solution.

[0105] To facilitate understanding of the technical solutions of the embodiments of this application, the technical solutions of this application are described in detail below through specific embodiments. The above-mentioned related technologies are optional solutions and can be arbitrarily combined with the technical solutions of the embodiments of this application, all of which fall within the protection scope of the embodiments of this application. The embodiments of this application include at least some of the following contents.

[0106] Figure 7 This is a schematic diagram of the network architecture provided in the embodiments of this application. Figure 8a ,like Figure 8bAs shown in the embodiments of this application, an access network architecture is provided, which includes a DU and a CU. The DU has a first protocol stack, and the CU has a second protocol stack. The first protocol stack includes a Data Plane Processing Layer (DPPL), a Media Access Control Layer (MAC), and a Physical Layer (PHY). The second protocol stack includes a Radio Resource Control Layer (RRC). The DPPL layer is located above the MAC layer, and the MAC layer is located above the PHY layer. The RRC layer is used to control the layers of the first protocol stack of the first node. Specifically, the RRC layer is located in the CU, and the DPPL and MAC layers are located in the DU. An NG user plane interface (NG-U interface) exists between the DU and the core network, allowing the DU to directly receive service data sent by the core network. Only a control interface exists between the DU and the CU. This interface implements control plane functions, including application protocols and signaling bearers for transmitting application protocol messages. This control interface can be called an E1 interface or an F1-C interface, or other names are not limited in this application. In the above scheme, the DPPL entity is a newly defined entity. The DPPL entity has all the capabilities of the PDCP entity, RLC entity, and SDAP entity. The functions of the DPPL entity are a simplification and merging of the functions of the PDCP entity, RLC entity, and SDAP entity. The DPPL entity can be called a data plane processing layer entity. Of course, the DPPL entity can also have other names, which are not limited in this application.

[0107] This application proposes a handover process based on the aforementioned access network architecture. Through parallel design, the handover preparation, handover execution, and handover completion phases are parallelized, reducing handover interruptions and overall handover latency, thus achieving reliable and low-latency handover. Specifically, refer to... Figure 8a , Figure 2 This is a flowchart illustrating the switching method provided in the embodiments of this application. Figure 8a ,like Figure 8b As shown, the switching method includes the following steps:

[0108] Step 601: After receiving the handover request message sent by the second control unit, the first control unit sends a UE context establishment request message to the first user unit.

[0109] In this embodiment, the first control unit can be represented as a first CU, the first user unit can be represented as a first DU, the second control unit can be represented as a second CU, and the second user unit can be represented as a second DU. The control unit can also be called a centralized unit, and the user unit can also be called a distributed unit; the control unit and user unit can also have other names.

[0110] In this embodiment, the first control unit and the first user unit are network nodes on the first cell side, and the second control unit and the second user unit are network nodes on the second cell side. The first cell can be called the source cell or the serving cell, and the second node can be called the target cell or the candidate cell. The first cell and the second cell can also have other names.

[0111] In some implementations, if the second CU determines that an XN connection exists in the first cell, it sends a handover request message (HANDOVER REQUEST) to the first CU. This message carries access network resources and configuration information allocated to the second cell, as well as information such as bearer service configuration.

[0112] In some implementations, after receiving the handover request message, the first CU performs user resource allocation and handover resource allocation strategies based on the configuration information carried in the handover request message. Specifically, the first CU performs user handover-related resource allocation, admission control, and establishment of relevant user contexts on the CU side, and sends a UE context establishment request message to the first DU, triggering the context establishment process between the first CU and the first DU.

[0113] Step 602: The first control unit receives a UE context establishment response message sent by the first user unit. The UE context establishment response message carries a first TNL address. The first TNL address is used for data fronthaul between the second user unit and the first user unit.

[0114] In some implementations, after receiving the UE context establishment request message sent by the first CU, the first DU performs a DU-side context establishment process and determines whether to allocate a first TNL address. The first TNL address is used for data fronthaul between the first DU and the second DU; therefore, the first TNL address can also be called the data fronthaul TNL address. After determining that the first TNL address has been allocated, the first DU sends a UE context establishment response message to the first CU, which carries the first TNL address.

[0115] In some implementations, after receiving the UE context establishment request message from the first CU, the first DU will also perform a resource allocation process. When the first DU sends a UE context establishment response message to the first CU, the message also carries relevant allocated resources. After receiving the relevant allocated resources from the first DU, the first CU generates a handover reconfiguration message based on the resources allocated by the first DU and the resources of the first CU.

[0116] As can be seen from the above, the handover method provided in this application embodiment involves a first control unit sending a UE context establishment request message to a first user unit after receiving a handover request message sent by a second control unit; receiving a UE context establishment response message sent by the first user unit, the UE context establishment response message carrying a first TNL address for data front-passing between the second user unit and the first user unit; thus, by carrying the TNL address in the UE context management signaling, the data plane latency of the handover process is reduced, thereby improving the handover success rate.

[0117] In some implementations, the first control unit sends a handover request confirmation message to the second control unit, the handover request confirmation message carrying a first TNL address; wherein, the handover request confirmation message is used to trigger a UE context modification procedure between the second control unit and the second user unit.

[0118] Here, after executing step 602 above, after the first CU and the first DU complete the UE context establishment process, the first CU generates a handover reconfiguration message based on the resources allocated by the first DU and the resources of the first CU. The first CU combines the generated handover reconfiguration message with the first TNL address information to form a handover request confirmation message HANDOVER REQUEST ACKNOWLEDGE and sends it to the second CU. At the same time, the UE context modification process between the second CU and the second DU is triggered.

[0119] In some implementations, the handover process is executed in parallel while the first CU sends a handover request confirmation message to the second CU. Specifically, the handover request confirmation message triggers a UE context modification process between the second CU and the second DU. After receiving the handover request confirmation message sent by the first CU, the second CU executes the handover process of the second cell.

[0120] Here, the second CU receives a handover request confirmation message from the first CU, which carries the first TNL address and a handover reconfiguration message. The second CU sends a UE context modification request message to the second DU, which carries the first TNL address handover reconfiguration message. The second DU then sends a UE context modification confirmation message to the second CU. Upon receiving the UE context modification request message from the second CU, the second DU stops transmitting data in the original cell. The second DU performs data fronthaul between the first TNL and the first DU, and, triggered by the handover reconfiguration message, transparently transmits a handover command to the UE. Upon receiving the handover command, the UE begins the handover process.

[0121] The handover method provided in this application embodiment executes the following data link establishment process in parallel while performing the step of sending a handover request confirmation message from the first CU to the second CU, specifically:

[0122] The first control unit sends a path switching request message to the core network and receives a path switching request confirmation message from the core network. The path switching request message carries a second TNL address, which is used for downlink data transmission between the core network and the first user unit. The path switching request confirmation message carries a third TNL address, which is used for uplink data transmission between the first user unit and the core network.

[0123] Here, the first CU sends a PATH SWITCH REQUEST message to the core network. This message carries the second TNL address allocated to the first DU. The second TNL address is the downlink data fronthaul TNL address information, used for downlink data transmission between the core network and the first DU. After receiving the PATH SWITCH REQUEST message, the core network triggers the establishment of a link and suspends the data link. Simultaneously, it allocates uplink TNL addresses and other information to the first DU, including a third TNL address for uplink data transmission. The core network then sends a PATHSWITCH REQUEST ACKNOWLEDGE message to the first CU, which also carries the third TNL address.

[0124] In some implementations, the data link establishment process further includes: the first control unit sending a UE context modification request message to the first user unit, the UE context modification request message carrying a third TNL address.

[0125] Here, the first CU receives a PATH SWITCH REQUESTACKNOWLEDGE message from the core network, which carries the third TNL address allocated by the core network, i.e., the uplink TNL address for path switching, and other information. Then, the first CU sends the third TNL address and other information to the first DU through the UE context modification procedure, thereby completing the data transmission link establishment process between the first DU and the core network. Specifically, the first CU sends a UE context modification request message to the first DU, which carries the third TNL address. The first DU receives the UE context modification request message carrying the third TNL address from the first CU and sends a UE context modification confirmation message to the first CU. The first DU can then perform uplink data transmission with the core network based on the third TNL address. Thus, by carrying the TNL address in the UE context management signaling, parallel air interface handover is achieved, reducing data plane latency during the handover process.

[0126] As can be seen from the above, the handover method provided in this application embodiment involves a first control unit sending a path handover request message carrying a second TNL address to the core network and receiving a path handover request confirmation message carrying a third TNL address from the core network. The second TNL address is used for downlink data transmission between the core network and the first user unit, and the third TNL address is used for uplink data transmission between the first user unit and the core network. In this way, the establishment of a handover path in the core network is realized during the handover process, which can technically avoid handover failure caused by the failure to establish a link with the core network during the handover process.

[0127] In some implementations, refer to Figure 8b The DU has an NG user plane interface (NG-U interface) with the core network, allowing the DU to directly receive service data sent by the core network. The first DU can transmit downlink data with the core network using the second TNL address and uplink data using the third TNL address.

[0128] In some implementations, the first control unit has a first interface with the first user unit and / or the second user unit, the first interface being used for exchanging UE context management-related signaling between the first control unit and the first user unit and / or the second user unit.

[0129] Here, refer to Figure 3 , Figure 9 This is a data transmission diagram provided in an embodiment of this application. A control interface exists between the DU and CU. This interface implements control plane functions, including application protocols and signaling bearers for transmitting application protocol messages, such as signaling related to UE context management. This control interface can be a first interface between the first CU and the first DU and / or the second DU. This first interface can also be called the X1 interface, and may have other names; this application does not limit its scope.

[0130] In some implementations, the signaling related to UE context management implemented through the first interface can be the signaling of the UE context establishment process, including a UE context establishment request message, which can be represented as X1 UE Context SetupRequest; a UE context establishment confirmation message, which can be represented as X1 UE Context Setup Response; and a UE context establishment failure message, which can be represented as X1 UE Context Setup Failure.

[0131] In some implementations, the signaling related to UE context management implemented through the first interface can be the signaling of the UE context modification process, including a UE context modification request message, which can be represented as X1 UE ContextModification Required, and a UE context modification confirmation message, which can be represented as X1 UE ContextModification Confirm.

[0132] In some implementations, the signaling related to UE context management implemented through the first interface can be the signaling for the UE context release procedure, including a UE context release command message, which can be represented as X1 UE Context ReleaseCommand, and a UE context release complete message, which can be represented as X1 UE Context Release Complete.

[0133] In some implementations, the second DU performs data forwarding with the first DU based on the first TNL address.

[0134] Here, the second DU assigns a unified SN number to the multiple service data units (SDUs) of the DPPL. Specifically, refer to... Figure 4 and Figure 9 , Figure 7 This is a schematic diagram of the data format corresponding to the protocol layer provided in the embodiments of this application. Figure 8a . Reference Figure 8b Data first reaches the DPPL layer via QoS streams. The DPPL layer is responsible for mapping data from different QoS streams to different DRBs, adding QoS stream identifiers to the data, and then performing DPPL SDU processing, i.e., uniformly assigning SN numbers, ultimately generating a DPPL PDU. (Refer to...) Figure 8a , Figure 2 This is a schematic diagram of the data format corresponding to the protocol layer provided in the embodiments of this application. Figure 8a This DPPL PDU can also be represented as an SDU in the MAC layer. Thus, compared to the data in the 5G protocol stack, the header of the SDU data packet in the fronthaul MAC layer accounts for a smaller proportion of the user data, effectively improving the effective information ratio of air interface data transmission.

[0135] In some implementations, the second DU sends a Sequence Number State Transition Message (SN STATUSTRANSFER) to the first DU. This message carries the forwarding data DPPL SDU (MAC SDU) that the second DU is forwarding to the first DU. The second DU stops forwarding data until it receives a handover success message from the first CU, triggering the UE context release procedure between the second CU and the second DU. That is, before receiving the handover success message from the first CU, the second DU will continue to transmit downlink data packets to the first DU based on the first TNL address.

[0136] Figure 8b This is a flowchart illustrating the switching method provided in the embodiments of this application. Figure 8b ,like Figure 3 As shown, the switching method includes the following steps:

[0137] Step 901: After the second control unit sends a handover request message to the first control unit, it receives a handover request confirmation message sent by the first control unit. The handover request confirmation message carries the first TNL address. The first TNL address is used for data forwarding between the second user unit and the first user unit.

[0138] Here, if the second CU determines that an XN connection exists in the target cell for handover, it sends a handover request message to the first CU. This message carries the access network resources and configuration information allocated by the source cell, as well as information such as the bearer service configuration.

[0139] In some implementations, after receiving the handover request message, the first CU performs user resource allocation and handover resource allocation strategy according to the configuration information carried in the handover request message, and triggers the context establishment process between the first CU and the first DU through the first interface.

[0140] Specifically, after receiving the UE context establishment request message from the first CU, the first DU performs a DU-side context establishment process and resource allocation process, and determines whether to allocate a first TNL address. The first TNL address is used for data fronthaul with the second DU. After determining to allocate the first TNL address, the first DU sends a UE context establishment response message to the first CU, which carries the first TNL address and related allocated resources. After receiving the UE context establishment response message from the first DU, the first CU generates a handover reconfiguration message based on the resources allocated by the first DU and the resources of the first CU. The first CU combines the generated handover reconfiguration message with the first TNL address information to form a handover request confirmation message, and sends it to the second CU.

[0141] In some implementations, the second CU receives a handover request confirmation message sent by the first CU, the handover request confirmation message carrying the first TNL address. The handover request confirmation message triggers a UE context modification procedure between the second CU and the second DU. After receiving the handover request confirmation message sent by the first CU, the second CU executes the handover procedure for the second cell.

[0142] Step 902: The second control unit sends a UE context modification request message to the second user unit. The UE context modification request message carries the first TNL address.

[0143] Here, the second CU receives a handover request confirmation message from the first CU, which carries the first TNL address and a handover reconfiguration message. The second CU sends a UE context modification request message to the second DU, which carries the first TNL address handover reconfiguration message. The second DU then sends a UE context modification confirmation message to the second CU. Upon receiving the UE context modification request message from the second CU, the second DU stops transmitting data in the original cell. The second DU performs data fronthaul between the first TNL and the first DU, and, triggered by the handover reconfiguration message, transparently transmits a handover command to the UE. Upon receiving the handover command, the UE begins the handover process.

[0144] As can be seen from the above, the handover method provided in this application embodiment involves the second control unit sending a handover request message to the first control unit and then receiving a handover request confirmation message carrying a first TNL address from the first control unit; the second control unit then sends a UE context modification request message carrying the first TNL address to the second user unit, where the first TNL address is used for data forwarding between the second user unit and the first user unit; thus, by carrying the TNL address in the UE context management signaling, the data plane latency of the handover process is reduced, thereby improving the handover success rate.

[0145] In some implementations, a second interface is provided between the second control unit and the second user unit, the second interface being used for exchanging UE context management-related signaling between the second control unit and the second user unit.

[0146] Specifically, refer to Figure 10 A control interface exists between the DU and CU. This interface implements control plane functions, including application protocols and signaling bearers for transmitting application protocol messages, such as UE context management-related signaling. This control interface can be a second interface between the second CU and the second DU. This second interface can also be called the X1 interface, and it can have other names as well. This application does not limit the specific names for this interface.

[0147] In some implementations, the signaling related to UE context management implemented through the second interface can be the signaling of the UE context establishment process, including a UE context establishment request message, which can be represented as X1 UE Context SetupRequest; a UE context establishment confirmation message, which can be represented as X1 UE Context Setup Response; and a UE context establishment failure message, which can be represented as X1 UE Context Setup Failure.

[0148] In some implementations, the signaling related to UE context management implemented through the second interface can be the signaling of the UE context modification process, including a UE context modification request message, which can be represented as X1 UE ContextModification Required, and a UE context modification confirmation message, which can be represented as X1 UE ContextModification Confirm.

[0149] In some implementations, the signaling related to UE context management implemented through the second interface can be the signaling for the UE context release procedure, including a UE context release command message, which can be represented as X1 UE Context ReleaseCommand, and a UE context release completion message, which can be represented as X1 UE Context Release Complete.

[0150] In some implementations, the second DU performs data forwarding with the first DU based on the first TNL address.

[0151] Here, the second DU assigns a unified SN number to the multiple service data units (SDUs) of the DPPL. Specifically, refer to... Figure 5 and Figure 10 , Figure 5 This is a schematic diagram of a data format corresponding to a protocol layer provided in an embodiment of this application. Figure 7 . Reference Figure 7 Data first reaches the DPPL layer via QoS streams. The DPPL layer is responsible for mapping data from different QoS streams to different DRBs, adding QoS stream identifiers to the data, and then performing DPPL SDU processing, i.e., uniformly assigning SN numbers, ultimately generating a DPPL PDU. (Refer to...) Figure 8a , Figure 8b This is a schematic diagram of the data format corresponding to the protocol layer provided in the embodiments of this application. Figure 8aThis DPPL PDU can also be represented as an SDU in the MAC layer. Thus, compared to the data in the 5G protocol stack, the header of the SDU data packet in the fronthaul MAC layer accounts for a smaller proportion of the user data, effectively improving the effective information ratio of air interface data transmission.

[0152] In some implementations, the second DU sends an SN STATUS TRANSFER message to the first DU, carrying the forwarding data DPPL SDU (MAC SDU) that the second DU is forwarding to the first DU. The second DU stops forwarding data until it receives a handover success message from the first CU, triggering the UE context release procedure between the second CU and the second DU. That is, before receiving the handover success message from the first CU, the second DU will continue to transmit downlink data packets to the first DU based on the first TNL address.

[0153] In some implementations, the second CU receives a UE context release message from the first CU, indicating that the UE has successfully switched to the first cell. Upon receiving this message, the second CU triggers a UE context release procedure between the second CU and the second DU. Specifically, the second CU sends a UE context release command message to the second DU and receives a UE context release completion message from the second DU. After receiving the UE context release command message from the second CU, the second DU stops transmitting downlink data packets to the first DU and sends a UE context release completion message to the second CU.

[0154] Figure 2 This is a flowchart illustrating the switching method provided in the embodiments of this application. Figure 8a ,like Figure 8b As shown, the switching method includes the following steps:

[0155] Step 1001: After receiving the UE context establishment request message sent by the first control unit, the first user unit sends a UE context establishment response message to the first control unit. The UE context establishment response message carries the first TNL address. The first TNL address is used for data fronthaul between the second user unit and the first user unit.

[0156] In this embodiment, after receiving the UE context establishment request message sent by the first CU, the first DU performs a DU-side context establishment process and determines whether to allocate a first TNL address. The first TNL address is used for data fronthaul between the first DU and the second DU; therefore, the first TNL address can also be called the data fronthaul TNL address. After determining that the first TNL address has been allocated, the first DU sends a UE context establishment response message to the first CU, which carries the first TNL address.

[0157] In some implementations, after receiving the UE context establishment request message from the first CU, the first DU will also perform a resource allocation process. When the first DU sends a UE context establishment response message to the first CU, the message also carries relevant allocated resources. After receiving the relevant allocated resources from the first DU, the first CU generates a handover reconfiguration message based on the resources allocated by the first DU and the resources of the first CU.

[0158] As can be seen from the above, the handover method provided in this application embodiment involves the first user unit receiving a UE context establishment request message sent by the first control unit and then sending a UE context establishment response message carrying a first TNL address to the first control unit. The first TNL address is used for data forwarding between the second user unit and the first user unit. In this way, by carrying the TNL address in the UE context management signaling, the data plane latency of the handover process is reduced, thereby improving the handover success rate.

[0159] The handover method provided in this application embodiment executes the following data link establishment process in parallel while performing the step of sending a handover request confirmation message from the first CU to the second CU, specifically:

[0160] The first CU sends a PATH SWITCH REQUEST message to the core network. This message carries the second TNL address allocated to the first DU. The second TNL address is the downlink data fronthaul TNL address information, used for downlink data transmission between the core network and the first DU. Upon receiving the PATH SWITCH REQUEST message, the core network triggers link establishment and suspends the data link. Simultaneously, it allocates uplink TNL addresses and other information to the first DU, including a third TNL address for uplink data transmission. The core network then sends a PATH SWITCH REQUEST ACKNOWLEDGE message to the first CU, which also carries the third TNL address.

[0161] In some implementations, the data link establishment process further includes: the first user unit receiving a UE context modification request message sent by the first control unit, the UE context modification request message carrying a third TNL address, the third TNL address being used for uplink data transmission between the first user unit and the core network.

[0162] Here, the first CU sends the third TNL address to the first DU through the UE context modification procedure, thereby completing the data transmission link establishment process between the first DU and the core network. Specifically, the first CU sends a UE context modification request message to the first DU, which carries the third TNL address. The first DU receives the UE context modification request message carrying the third TNL address from the first CU and sends a UE context modification confirmation message to the first CU. The first DU can then perform uplink data transmission with the core network based on the third TNL address. In this way, by carrying the TNL address in the UE context management signaling, parallel air interface handover is achieved, reducing the data plane latency during the handover process.

[0163] In some implementations, the first user unit sends a data switching data packet to the core network, which is used to indicate that uplink data transmission is switched from the second user unit to the first user unit.

[0164] Here, refer to Figure 8b The DU and the core network have an NG user plane interface (NG-U interface), allowing the first DU to directly send data handover packets to the core network. Upon receiving the data handover packets, the core network switches the uplink data transmission from the second DU to the first DU.

[0165] Specifically, the data switching data packet is either a data plane control packet or a valid data plane data packet. A valid data plane data packet refers to a data packet transmitted through a third TNL address.

[0166] Here, when the data handover packet is a valid data plane packet, the first DU sends a packet to the core network based on the third TNL address to indicate a switch from the second DU to the first DU for uplink data transmission. When the data handover packet is a data plane control packet, the first DU sends a packet to the core network based on the GTPU tunnel reserved field to indicate a switch from the second DU to the first DU for uplink data transmission. The data handover packet can be a data plane control packet (such as a startendmarker), which can be indicated by the GTPU tunnel reserved field, such as using the GTPU field decimal message type value reserved field as the message indication field. The GTPU tunnel reserved field is part of the GPRS Tunneling Protocol (GTP) header.

[0167] In some implementations, a first interface is provided between the first user unit and the first control unit, and the first interface is used for the first control unit and the first user unit to exchange signaling related to UE context management.

[0168] Specifically, refer toFigure 3 A control interface exists between the DU and CU. This interface implements control plane functions, including application protocols and signaling bearers for transmitting application protocol messages, such as UE context management-related signaling. This control interface can be a first interface between the first CU and the first DU and / or the second DU. This first interface can also be called the X1 interface, and it can have other names as well. This application does not limit the specific names for this interface.

[0169] In some implementations, the signaling related to UE context management implemented through the first interface can be the signaling of the UE context establishment process, including a UE context establishment request message, which can be represented as X1 UE Context SetupRequest; a UE context establishment confirmation message, which can be represented as X1 UE Context Setup Response; and a UE context establishment failure message, which can be represented as X1 UE Context Setup Failure.

[0170] In some implementations, the signaling related to UE context management implemented through the first interface can be the signaling of the UE context modification process, including a UE context modification request message, which can be represented as X1 UE ContextModification Required, and a UE context modification confirmation message, which can be represented as X1 UE ContextModification Confirm.

[0171] In some implementations, the signaling related to UE context management implemented through the first interface can be the signaling for the UE context release procedure, including a UE context release command message, which can be represented as X1 UE Context ReleaseCommand, and a UE context release complete message, which can be represented as X1 UE Context Release Complete.

[0172] In some implementations, a third interface is provided between the first user unit and the second user unit, which is used for data forwarding from the second user unit to the first user unit.

[0173] Here, refer to Figure 11 The network nodes on the first and second cell sides adopt a DU and CU separation architecture. The network nodes on the first cell side include a first CU and a first DU, and the network nodes on the second cell side include a second CU and a second DU. A third interface exists between the two network nodes, between the first DU and the second DU. It should be noted that the third interface can be called a DN interface, and the first interface can have other names; this application does not limit this.

[0174] In some implementations, when a third interface is deployed for inter-base station connectivity, the first DU and the second DU can interact through the third interface to establish a DN Setup procedure or a third interface update procedure to configure neighbor cell information between the first DU and the second DU. The neighbor cell information configuration is used for destination cell selection, message routing, and data forwarding between the handover procedures on the third interface.

[0175] In some implementations, the format of the data transmitted between the first user unit and the second user unit includes a MAC header and a DPPL header, and the transmitted data is a Service Data Unit (SDU) of the MAC layer.

[0176] Here, the second DU assigns a unified SN number to the multiple service data units (SDUs) of the DPPL. Specifically, refer to... Figure 6 and Figure 11 , Figure 8a This is a schematic diagram of a data format corresponding to a protocol layer provided in an embodiment of this application. Figure 8b . Reference Figure 8a Data first reaches the DPPL layer via QoS streams. The DPPL layer is responsible for mapping data from different QoS streams to different DRBs, adding QoS stream identifiers to the data, and then performing DPPL SDU processing, i.e., uniformly assigning SN numbers, ultimately generating a DPPL PDU. (Refer to...) Figure 2 , Figure 8a This is a schematic diagram of the data format corresponding to the protocol layer provided in the embodiments of this application. Figure 8b This DPPL PDU can also be represented as an SDU in the MAC layer. Thus, compared to the data in the 5G protocol stack, the header of the SDU data packet in the fronthaul MAC layer accounts for a smaller proportion of the user data, effectively improving the effective information ratio of air interface data transmission.

[0177] In some implementations, the second DU sends an SN STATUS TRANSFER message to the first DU, carrying the forwarding data DPPL SDU (MAC SDU) that the second DU is forwarding to the first DU. The second DU stops forwarding data until it receives a handover success message from the first CU, triggering the UE context release procedure between the second CU and the second DU. That is, before receiving the handover success message from the first CU, the second DU will continue to transmit downlink data packets to the first DU based on the first TNL address.

[0178] Figure 8b This is a flowchart illustrating the switching method provided in the embodiments of this application. Figure 3 ,like Figure 7As shown, the switching method includes the following steps:

[0179] Step 1101: The second user unit receives a UE context modification request message sent by the second control unit. The UE context modification request message carries a first TNL address. The first TNL address is used for data fronthaul between the second user unit and the first user unit.

[0180] In this embodiment, the second user unit can be represented as a second DU, and the second control unit can be represented as a second CU. The control unit can also be called a centralized unit, and the user unit can also be called a distributed unit; the control unit and user unit can also have other names. The first control unit and the first user unit are network nodes on the first cell side, and the second control unit and the second user unit are network nodes on the second cell side. The first cell can be called a source cell or a serving cell, and the second node can be a target cell or a candidate cell; the first cell and the second cell can also have other names.

[0181] In this embodiment, after receiving the UE context establishment response message from the first DU, the first CU generates a handover reconfiguration message based on the resources allocated by the first DU and the resources of the first CU carried in the message. The first CU combines the generated handover reconfiguration message with the first TNL address information to form a handover request confirmation message. The first CU sends the handover request confirmation message to the second CU, thereby triggering the UE context modification process between the second CU and the second DU. The second CU receives the handover request confirmation message sent by the first CU, which carries the first TNL address. Simultaneously, the handover request confirmation message received by the second CU triggers the second CU to send a UE context modification request message to the second DU, which carries the first TNL address for data fronthaul between the second DU and the first DU.

[0182] In some implementations, the second user unit forwards data to the first user unit based on the first TNL address.

[0183] The format of the data transmitted between the second user unit and the first user unit includes a MAC header and a DPPL header, and the transmitted data is the Service Data Unit (SDU) of the MAC layer.

[0184] Here, the second DU assigns a unified SN number to the multiple service data units (SDUs) of the DPPL. Specifically, refer to... Figure 7 and Figure 12 , Figure 7 This is a schematic diagram of a data format corresponding to a protocol layer provided in an embodiment of this application. Figure 12 . Reference Figure 13Data first reaches the DPPL layer via QoS streams. The DPPL layer is responsible for mapping data from different QoS streams to different DRBs, adding QoS stream identifiers to the data, and then performing DPPL SDU processing, i.e., uniformly assigning SN numbers, ultimately generating a DPPL PDU. (Refer to...) Figure 1 , Figure 13 This is a schematic diagram of the data format corresponding to the protocol layer provided in the embodiments of this application. Figure 13 This DPPL PDU can also be represented as an SDU in the MAC layer. Thus, compared to the data in the 5G protocol stack, the header of the SDU data packet in the fronthaul MAC layer accounts for a smaller proportion of the user data, effectively improving the effective information ratio of air interface data transmission.

[0185] In some implementations, the second DU sends an SN STATUS TRANSFER message to the first DU, carrying the forwarding data DPPL SDU (MAC SDU) that the second DU is forwarding to the first DU. The second DU stops forwarding data until it receives a handover success message from the first CU, triggering the UE context release procedure between the second CU and the second DU. That is, before receiving the handover success message from the first CU, the second DU will continue to transmit downlink data packets to the first DU based on the first TNL address.

[0186] In some implementations, the second CU receives a UE context release message from the first CU, indicating that the UE has successfully switched to the first cell. Upon receiving this message, the second CU triggers a UE context release procedure between the second CU and the second DU. Specifically, the second CU sends a UE context release command message to the second DU and receives a UE context release completion message from the second DU. After receiving the UE context release command message from the second CU, the second DU stops transmitting downlink data packets to the first DU and sends a UE context release completion message to the second CU.

[0187] In some implementations, a second interface is provided between the second user unit and the second control unit, the second interface being used for the second control unit and the second user unit to exchange signaling related to UE context management.

[0188] Specifically, refer to Figure 13 A control interface exists between the DU and CU. This interface implements control plane functions, including application protocols and signaling bearers for transmitting application protocol messages, such as UE context management-related signaling. This control interface can be a second interface between the second CU and the second DU. This second interface can also be called the X1 interface, and it can have other names as well. This application does not limit the specific names for this interface.

[0189] In some implementations, the signaling related to UE context management implemented through the second interface can be the signaling of the UE context establishment process, including a UE context establishment request message, which can be represented as X1 UE Context SetupRequest; a UE context establishment confirmation message, which can be represented as X1 UE Context Setup Response; and a UE context establishment failure message, which can be represented as X1 UE Context Setup Failure.

[0190] In some implementations, the signaling related to UE context management implemented through the second interface can be the signaling of the UE context modification process, including a UE context modification request message, which can be represented as X1 UE ContextModification Required, and a UE context modification confirmation message, which can be represented as X1 UE ContextModification Confirm.

[0191] In some implementations, the signaling related to UE context management implemented through the second interface can be the signaling for the UE context release procedure, including a UE context release command message, which can be represented as X1 UE Context ReleaseCommand, and a UE context release completion message, which can be represented as X1 UE Context Release Complete.

[0192] In some implementations, a third interface is provided between the second user unit and the first user unit, which is used for the second user unit to transmit data to the first user unit.

[0193] Here, refer to Figure 14 The network nodes on the first and second cell sides adopt a DU and CU separation architecture. The network nodes on the first cell side include a first CU and a first DU, and the network nodes on the second cell side include a second CU and a second DU. A third interface exists between the two network nodes, between the first DU and the second DU. It should be noted that the third interface can be called a DN interface, and the first interface can have other names; this application does not limit this.

[0194] In some implementations, when a third interface is deployed for inter-base station connectivity, the first DU and the second DU can exchange neighbor cell information configuration between the DUs through the DNSetup Procedure or DN Configuration Update Procedure. The neighbor cell information configuration is used for destination cell selection, message routing, and data forwarding between the third interfaces during handover procedures.

[0195] Example 1

[0196] Figure 2 This is a flowchart illustrating a switching method provided in an embodiment of this application. Figure 14 ,like Figure 14 As shown, a handover process based on a new simplified architecture is proposed. Through parallel design, the handover preparation, handover execution, and handover completion phases are parallelized, reducing handover interruptions and overall handover latency, thus achieving reliable and low-latency handover. The specific handover steps are as follows:

[0197] Step 1201: The second CU sends a handover request message to the first CU.

[0198] Here, if the second CU determines that there is an XN connection in the target cell for handover, it sends a handover request message to the cell where the first CU is located. This message carries the access network resources and configuration information allocated by the source cell, as well as the bearer service configuration and other information, so that the first CU can perform user resource allocation and handover resource allocation strategies.

[0199] Step 1202: The first CU and the first DU perform a UE context establishment process based on the X1 interface, which carries the first TNL address.

[0200] Here, the first CU performs resource allocation and admission control related to user handover, establishes the relevant user context for the first CU, and sends an X1 UE Context Setup Request message to the first DU, triggering the X1 UE Context Setup Procedure. The T-DU performs DU-side context establishment and resource allocation, determines whether to allocate a data fronthaul TNL address, and sends an X1 UE Context Setup Response message to the T-CU, which carries the downlink data transmission TNL address and related allocated resources.

[0201] The following processes are executed in parallel:

[0202] Step 1203a: The first CU sends a handover request confirmation message to the second CU.

[0203] Here, the first CU generates a handover reconfiguration message based on the resources allocated by the first DU and the resources of the first CU, and together with the first TNL address information, forms a handover request confirmation message and sends it to the second CU to trigger the air interface handover and data forwarding process.

[0204] Data link establishment process:

[0205] Step 1203b: Establishing a path switching process between the first CU and the core network.

[0206] Here, the first CU sends a path switching request message to the core network, carrying information such as the second TNL address allocated by the first DU to the core network. After receiving the message, the core network triggers the core network to establish a link and suspend the data link, and sends a path switching response message to the first CU, carrying information such as the third TNL address.

[0207] Step 1204b: The first CU and the first DU perform a UE context modification procedure based on the X1 interface, which carries the third TNL address.

[0208] Here, the first CU receives a path handover response message from the core network, which carries the third TNL address information allocated by the core network. The first CU then sends the third TNL address and other information for the uplink handover to the first DU through the X1 UE Context Modification Procedure, completing the data transmission link establishment process between the first DU and the core network.

[0209] Switching process

[0210] Step 1204a: The second CU and the second DU perform a UE context modification procedure based on the X1 interface, which carries the first TNL address.

[0211] Here, after the second CU receives the handover request confirmation message, it triggers the X1 UEContext Modification Procedure between the second CU and the second DU. The X1 UE ContextModification Request message sent by the second CU to the second DU carries the first TNL address information and the handover configuration information generated by the destination cell, triggering the RRC air interface handover reconfiguration process and the data forwarding process between the first DU and the second DU.

[0212] Step 1205: The second DU sends an SN status transmission message to the first DU.

[0213] Step 1206: The second DU sends data to the first DU.

[0214] Step 1207: The first DU sends a data plane control packet or a valid data plane data packet to the core network.

[0215] Here, after the RACH handover procedure is successful, the first user unit sends a data handover packet to the core network. This data handover packet indicates that uplink data transmission is being switched from the second user unit to the first user unit. The data handover packet can be a data plane control packet or a valid data plane packet. A valid data plane packet refers to a packet transmitted via the third TNL address.

[0216] Step 1208: The second DU sends an end marker to the first DU.

[0217] Step 1209: The core network sends a new path to the first DU.

[0218] Step 1210: The first CU sends a UE context release message to the second CU.

[0219] Step 1211: UE context release procedure between the second CU and the second DU based on the X1 interface.

[0220] As can be seen from the above, the handover method provided in this application embodiment achieves handover reliability and low latency by reducing data interruptions and latency throughout the handover process, thus simplifying the handover process. Compared with the prior art, firstly, the signaling interaction process, such as steps 401-419, is reduced from 19 steps to 11 steps 1201-1211, that is, the number of handover messages is reduced to less than 60% of the original scheme, while improving the handover success rate. Secondly, the handover process provided in this application embodiment has a shorter data forwarding path compared with the prior art, and the data forwarding occurs at the underlying layer. When some information terminals have received the data while others have not, the protocol stack in the proposed embodiment can correctly identify all data packets that have not been correctly transmitted and forward them to the target base station, resulting in higher accuracy of data forwarding. Thirdly, the handover process provided in this application embodiment has higher data transmission efficiency compared with the prior art. Compared with the data in the 5G protocol stack, the header of the SDU data packet in the forwarded MAC layer accounts for a smaller proportion of the user data, which can effectively improve the effective information ratio of air interface data transmission. Fourthly, the handover process provided in this application embodiment is faster than the prior art in terms of data link handover. By carrying the TNL address in the UE context management signaling, it enables parallel execution of air interface handover and core network handover path establishment, reducing data plane latency during the handover process. Fifthly, establishing the core network handover path during the handover process can technically avoid handover failure caused by the failure to establish a link with the core network during the handover process.

[0221] Figure 14 This is a schematic diagram of the structural composition of the switching device provided in the embodiments of this application. Figure 15 Applied to the first control unit, such as Figure 3 As shown, the switching device 1300 includes:

[0222] The receiving unit 1301 is used to receive the switching request message sent by the second control unit.

[0223] The sending unit 1302 is used to send a UE context establishment request message to the first user unit.

[0224] The receiving unit 1301 is further configured to receive a UE context establishment response message sent by the first user unit, the UE context establishment response message carrying a first TNL address; the first TNL address is used for data forwarding between the second user unit and the first user unit.

[0225] In some embodiments, the sending unit 1302 is further configured to send a handover request confirmation message to the second control unit, the handover request confirmation message carrying the first TNL address; wherein, the handover request confirmation message is used to trigger a UE context modification procedure between the second control unit and the second user unit.

[0226] In some embodiments, the sending unit 1302 is further configured to send a path switching request message to the core network and receive a path switching request confirmation message sent by the core network; the path switching request message carries a second TNL address, which is used for downlink data transmission between the core network and the first user unit; the path switching request confirmation message carries a third TNL address, which is used for uplink data transmission between the first user unit and the core network.

[0227] In some embodiments, the sending unit 1302 is further configured to send a UE context modification request message to the first user unit, the UE context modification request message carrying the third TNL address.

[0228] In some implementations, the first control unit has a first interface with the first user unit and / or the second user unit, the first interface being used for the first control unit to exchange UE context management related signaling with the first user unit and / or the second user unit.

[0229] Those skilled in the art should understand that Figure 15 The functions of each unit in the switching device shown can be understood by referring to the relevant description of the aforementioned method. Figure 15 The functions of each unit in the switching device shown can be implemented by a program running on a processor or by specific logic circuits.

[0230] Figure 15 This is a schematic diagram of the structural composition of the switching device provided in the embodiments of this application. Figure 16 Applied to the second control unit, such as Figure 4 As shown, the switching device 1400 includes:

[0231] The sending unit 1401 is used to send a switching request message to the first control unit.

[0232] The receiving unit 1402 is used to receive a handover request confirmation message sent by the first control unit, the handover request confirmation message carrying a first TNL address; the first TNL address is used for data forwarding between the second user unit and the first user unit.

[0233] The sending unit 1401 is further configured to send a UE context modification request message to the second user unit, the UE context modification request message carrying the first TNL address.

[0234] In some implementations, the second control unit and the second user unit have a second interface, which is used for the second control unit and the second user unit to exchange UE context management related signaling.

[0235] Those skilled in the art should understand that Figure 16 The functions of each unit in the switching device shown can be understood by referring to the relevant description of the aforementioned method. Figure 16 The functions of each unit in the switching device shown can be implemented by a program running on a processor or by specific logic circuits.

[0236] Figure 16 This is a schematic diagram of the structural composition of the switching device provided in the embodiments of this application. Figure 17 Applied to the first user unit, such as Figure 17 As shown, the switching device 1500 includes:

[0237] The receiving unit 1501 is used to receive the UE context establishment request message sent by the first control unit.

[0238] The sending unit 1502 is used to send a UE context establishment response message to the first control unit. The UE context establishment response message carries a first TNL address. The first TNL address is used for data fronthaul between the second user unit and the first user unit.

[0239] In some embodiments, the receiving unit 1501 is further configured to receive a UE context modification request message sent by the first control unit, the UE context modification request message carrying a third TNL address, the third TNL address being used for uplink data transmission between the first user unit and the core network.

[0240] In some implementations, the sending unit 1502 is further configured to send a data switching data packet to the core network, the data switching data packet being used to indicate that uplink data transmission is switched from the second user unit to the first user unit.

[0241] In some implementations, the data switching data packet is a data plane control packet or a valid data plane data packet, wherein the valid data plane data packet refers to a data packet transmitted through the third TNL address.

[0242] In some implementations, the first user unit and the first control unit have a first interface, which is used for the first control unit and the first user unit to exchange UE context management related signaling.

[0243] In some implementations, a third interface is provided between the first user unit and the second user unit, the third interface being used for the second user unit to perform data forwarding to the first user unit.

[0244] In some implementations, the format of the data transmitted between the first user unit and the second user unit includes a MAC header and a DPPL header, and the transmitted data is a MAC SDU.

[0245] Those skilled in the art should understand that Figure 17 The functions of each unit in the switching device shown can be understood by referring to the relevant description of the aforementioned method. Figure 17 The functions of each unit in the switching device shown can be implemented by a program running on a processor or by specific logic circuits.

[0246] ​ This is a schematic diagram of the structural composition of the switching device provided in the embodiments of this application. ​ Applied to the second user unit, such as ​ As shown, the switching device 1600 includes:

[0247] The receiving unit 1601 is used to receive a UE context modification request message sent by the second control unit, the UE context modification request message carrying a first TNL address; the first TNL address is used for data fronthaul between the second user unit and the first user unit.

[0248] In some embodiments, the switching device 1600 further includes a sending unit 1602, which is used to perform data forwarding with the first user unit according to the first TNL address.

[0249] In some implementations, the second user unit and the second control unit have a second interface, which is used for the second control unit and the second user unit to exchange UE context management related signaling.

[0250] In some implementations, a third interface is provided between the second user unit and the first user unit, the third interface being used for the second user unit to perform data forwarding to the first user unit.

[0251] In some implementations, the format of the data transmitted between the second user unit and the first user unit includes a MAC header and a DPPL header, and the transmitted data is a MAC SDU.

[0252] Those skilled in the art should understand that ​ The functions of each unit in the switching device shown can be understood by referring to the relevant description of the aforementioned method. ​ The functions of each unit in the switching device shown can be implemented by a program running on a processor or by specific logic circuits.

[0253] ​ This is a schematic structural diagram of a network device 1700 provided in an embodiment of this application. ​ The network device 1700 shown includes a processor 1710, which can call and run computer programs from memory to implement the methods in the embodiments of this application.

[0254] Optionally, such as ​ As shown, the network device 1700 may further include a memory 1720. The processor 1710 can retrieve and run computer programs from the memory 1770 to implement the methods described in this embodiment.

[0255] The memory 1720 can be a separate device independent of the processor 1710, or it can be integrated into the processor 1710.

[0256] Optionally, such as ​ As shown, the network device 1700 may also include a transceiver 1730, and the processor 1710 may control the transceiver 1730 to communicate with other devices. Specifically, it may send information or data to other devices or receive information or data sent by other devices.

[0257] The transceiver 1730 may include a transmitter and a receiver. The transceiver 1730 may further include an antenna, and the number of antennas may be one or more.

[0258] Optionally, the network device 1700 may specifically be a network device in the embodiments of this application, and the network device 1700 may implement the corresponding processes implemented by the network device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0259] It should be understood that the processor in the embodiments of this application may be an integrated circuit chip with signal processing capabilities. In implementation, the steps of the above method embodiments can be completed by integrated logic circuits in the processor's hardware or by instructions in software form. The processor described above can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method.

[0260] It is understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDR SDRAM), Enhanced Synchronous DRAM (ESDRAM), Synchlink DRAM (SLDRAM), and Direct Rambus RAM (DR RAM). It should be noted that the memory used in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0261] It should be understood that the above-described memory is exemplary and not a limiting description. For example, the memory in the embodiments of this application may also be static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct memory bus RAM (DR RAM), etc. That is to say, the memory in the embodiments of this application is intended to include, but is not limited to, these and any other suitable types of memory.

[0262] This application also provides a computer-readable storage medium for storing computer programs.

[0263] Optionally, the computer-readable storage medium can be applied to the network device in the embodiments of this application, and the computer program causes the computer to execute the corresponding processes implemented by the network device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0264] Optionally, the computer-readable storage medium can be applied to the mobile terminal / terminal device in the embodiments of this application, and the computer program causes the computer to execute the corresponding processes implemented by the mobile terminal / terminal device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0265] This application also provides a computer program product, including computer program instructions.

[0266] Optionally, the computer program product can be applied to the network device in the embodiments of this application, and the computer program instructions cause the computer to execute the corresponding processes implemented by the network device in the various methods of the embodiments of this application. For the sake of brevity, they will not be described in detail here.

[0267] Optionally, the computer program product can be applied to the mobile terminal / terminal device in the embodiments of this application, and the computer program instructions cause the computer to execute the corresponding processes implemented by the mobile terminal / terminal device in the various methods of the embodiments of this application. For the sake of brevity, they will not be described in detail here.

[0268] This application also provides a computer program.

[0269] Optionally, the computer program can be applied to the network device in the embodiments of this application. When the computer program is run on the computer, it causes the computer to execute the corresponding processes implemented by the network device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0270] Optionally, the computer program can be applied to the mobile terminal / terminal device in the embodiments of this application. When the computer program is run on a computer, it causes the computer to execute the corresponding processes implemented by the mobile terminal / terminal device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0271] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0272] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0273] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0274] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0275] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0276] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0277] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A handover method, characterized by, The method comprises: After receiving the switching request message sent by the second control unit, the first control unit sends a UE context establishment request message to the first user unit; The first control unit receives the UE context establishment response message sent by the first user unit, and the UE context establishment response message carries a first TNL address; the first TNL address is used for data forwarding between the second user unit and the first user unit.

2. The method of claim 1, wherein, The method further comprises: The first control unit sends a switching request confirmation message to the second control unit, and the switching request confirmation message carries the first TNL address; wherein the switching request confirmation message is used to trigger a UE context modification process between the second control unit and the second user unit.

3. The method of claim 1, wherein, The method further comprises: The first control unit sends a path switching request message to the core network and receives a path switching request confirmation message sent by the core network; the path switching request message carries a second TNL address, and the second TNL address is used for downlink data transmission between the core network and the first user unit; the path switching request confirmation message carries a third TNL address, and the third TNL address is used for uplink data transmission between the first user unit and the core network.

4. The method of claim 1, wherein, The method further comprises: The first control unit sends a UE context modification request message to the first user unit, and the UE context modification request message carries the third TNL address.

5. The method according to any one of claims 1 to 4, characterized in that, The first control unit has a first interface with the first user unit and / or the second user unit, and the first interface is used for the first control unit to interact with the first user unit and / or the second user unit to exchange UE context management related signaling.

6. A handover method, characterized by, The method comprises: After the second control unit sends a switching request message to the first control unit, the first control unit receives a switching request confirmation message sent by the first control unit, and the switching request confirmation message carries a first TNL address; the first TNL address is used for data forwarding between the second user unit and the first user unit. The second control unit sends a UE context modification request message to the second user unit, and the UE context modification request message carries the first TNL address.

7. The method of claim 6, wherein, The second control unit has a second interface with the second user unit, and the second interface is used for the second control unit to interact with the second user unit to exchange UE context management related signaling.

8. A handover method, characterized by, The method comprises: After receiving the UE context establishment request message sent by the first control unit, the first user unit sends a UE context establishment response message to the first control unit, and the UE context establishment response message carries a first TNL address; the first TNL address is used for data forwarding between the second user unit and the first user unit.

9. The method of claim 8, wherein, The method further comprises: The first user unit receives a UE context modification request message sent by the first control unit, and the UE context modification request message carries a third TNL address, which is used for uplink data transmission between the first user unit and the core network.

10. The method of claim 9, wherein, The method further includes: The first user unit sends a data switching data packet to the core network, and the data switching data packet is used to indicate that uplink data transmission is switched from the second user unit to the first user unit.

11. The method of claim 10, wherein, The data switching data packet is a data plane control packet or an effective data plane data packet, and the effective data plane data packet refers to a data packet transmitted through the third TNL address.

12. The method of claim 8 or 9, wherein, The first user unit and the first control unit have a first interface, and the first interface is used for the first control unit and the first user unit to interact with each other in relation to UE context management signaling.

13. The method of claim 8 or 9, wherein, The first user unit and the second user unit have a third interface, and the third interface is used for the second user unit to forward data to the first user unit.

14. The method of claim 8 or 9, wherein, The format of the data forwarded between the first user unit and the second user unit includes a MAC header and a DPPL header, and the forwarded data is a MAC layer service data unit (SDU).

15. A handover method, characterized by, The method includes: The second user unit receives a UE context modification request message sent by the second control unit, and the UE context modification request message carries a first TNL address; and the first TNL address is used for data forwarding between the second user unit and the first user unit.

16. The method of claim 15, wherein, The method further includes: The second user unit forwards data to the first user unit according to the first TNL address.

17. The method of claim 15, wherein, The second user unit and the second control unit have a second interface, and the second interface is used for the second control unit and the second user unit to interact with each other in relation to UE context management signaling.

18. The method of claim 15 or 16, wherein, The second user unit and the first user unit have a third interface, and the third interface is used for the second user unit to forward data to the first user unit.

19. The method of claim 15 or 16, wherein, The format of the data forwarded between the second user unit and the first user unit includes a MAC header and a DPPL header, and the forwarded data is a MAC SDU.

20. A switching device, characterized by The device applied to the first control unit includes: A receiving unit configured to receive a switching request message sent by the second control unit; A sending unit configured to send a UE context establishment request message to the first user unit; The receiving unit is further configured to receive a UE context establishment response message sent by the first user unit, and the UE context establishment response message carries a first TNL address; and the first TNL address is used for data forwarding between the second user unit and the first user unit.

21. A switching device, characterized by The device applied to the second control unit includes: A sending unit configured to send a switching request message to the first control unit; The receiving unit is configured to receive a switching request acknowledgement message sent by the first control unit, and the switching request acknowledgement message carries a first TNL address; the first TNL address is used for data front transmission between the second user unit and the first user unit. The sending unit is further configured to send a UE context modification request message to the second user unit, and the UE context modification request message carries the first TNL address.

22. A switching device, characterized by The apparatus is applied to a first user unit, and the apparatus comprises: The receiving unit is configured to receive a UE context establishment request message sent by a first control unit. The sending unit is configured to send a UE context establishment response message to the first control unit, and the UE context establishment response message carries a first TNL address; the first TNL address is used for data front transmission between the second user unit and the first user unit.

23. A switching device, characterized by The apparatus is applied to a second user unit, and the apparatus comprises: The receiving unit is configured to receive a UE context modification request message sent by a second control unit, and the UE context modification request message carries a first TNL address; the first TNL address is used for data front transmission between the second user unit and a first user unit.

24. A network device, comprising: The apparatus comprises: A processor and a memory configured to store a computer program; the processor is configured to invoke and run the computer program stored in the memory to execute the method in any one of claims 1 to 19.

25. A computer-readable storage medium, characterized in that, A computer program for storing, which causes a computer to execute the method in any one of claims 1 to 19.

26. A computer program product, characterised in that, Computer program instructions for causing a computer to execute the method in any one of claims 1 to 19.

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