Data transmission method, and apparatus

Abstract

The present application provides a data transmission method, and an apparatus. The method is applied to a source base station during terminal device handover. The method comprises: sending a first handover request, the first handover request comprising quality of service (QoS) parameters of a protocol data unit (PDU) set of a terminal device; receiving first indication information, the first indication information being used for indicating processing capacity of a target base station for the PDU set during terminal device handover; and, on the basis of the first indication information, performing a handover operation. Thus, during inter-station handover, resource waste caused by capacity mismatch between base stations during cache data forwarding can be avoided, thus improving forwarding efficiency.

Description

Data transmission method and device

[0001] This application claims priority to the Chinese patent application with application number 202311015533.2 filed with the State Intellectual Property Office of China on August 10, 2023, and priority to the Chinese patent application with the invention name “Data Transmission Method and Device”, all contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communications, and more particularly, to a data transmission method and apparatus. Background Art

[0003] With the continuous development of communication technology, extended reality (XR) is one of the 5G multimedia applications that is currently being considered in the industrial field.

[0004] The 5G system forwards and processes data based on the granularity of quality of service flow (QoS flow) and guarantees its quality of service (QoS). The 5G core network (5GC) in the 5G system indicates the QoS requirements of different QoS flows to the radio access network (RAN) through the QoS profile (QoS profile). For ordinary services in the 5G system, QoS guarantees are only required at the granularity of protocol data unit (PDU), but for XR services, QoS guarantees are usually expected to be required at the granularity of PDU set (PDU set). For XR services, the base station is usually required to have the ability to process PDU set. Therefore, the base station will report its own processing capabilities for PDU set to the core network.

[0005] When inter-station handover occurs in a terminal device, how to avoid resource waste caused by capability mismatch between the source and target base stations during the handover process has become an urgent problem to be solved.

[0006] Summary of the Invention

[0007] The present application provides a data transmission method and apparatus, which can avoid resource waste caused by capability mismatch between base stations when forwarding cached data during inter-station switching, thereby improving forwarding efficiency.

[0008] In a first aspect, a data transmission method is provided, the method being applied to a source base station during a handover of a terminal device. The method comprises: sending a first handover request, the first handover request including quality of service (QoS) parameters for a protocol data unit (PDU) set of the terminal device; receiving first indication information, the first indication information being used to indicate a processing capability of a target base station for the PDU set during the handover of the terminal device; and performing a handover operation based on the first indication information.

[0009] In the above technical solution, the source base station fully considers the processing capability of the target base station for the PDU set and makes a reasonable switching decision, thereby avoiding the waste of link resources and even data decoding errors caused by the mismatch between the processing capabilities of the two base stations for the PDU set.

[0010] In combination with the first aspect, in some implementations of the first aspect, the QoS parameters include one or more of a protocol data unit set delay budget PSDB, a protocol data unit set error rate PSER, and a protocol data unit set integrity information PSIHI.

[0011] In combination with the first aspect, in certain implementations of the first aspect, performing a switching operation according to the first indication information includes: when the first indication information indicates that the target base station has the processing capability of the PDU set, sending a first cache data packet, the first cache data packet including relevant information of the PDU set.

[0012] In the above technical solution, when the first indication information indicates that the target base station has the PDU set processing capability, the source base station directly forwards the cached data to be forwarded to the target base station. Compared with the source base station directly forwarding the cached data to the target base station when the capability of the target base station is unknown, the solution of the present application can ensure that there is no waste of link resources when forwarding the cached data.

[0013] In combination with the first aspect, in certain implementations of the first aspect, performing a switching operation according to the first indication information includes: when the first indication information indicates that the target base station does not have the processing capability of the PDU set, sending a second cached data packet, the second cached data packet does not include relevant information of the PDU set; or, determining a new target base station; or, sending a second switching request to the target base station, the second switching request does not include QoS parameters of the PDU set.

[0014] In the above technical solution, when the first indication information indicates that the target base station does not have the PDU set processing capability, the source base station can reduce the packet header size of the forwarded data while ensuring that the inter-station switching process between the source base station and the target base station remains unchanged by removing the relevant information of the PDU set in the data packet of the cached data to be forwarded, thereby reducing the consumption of forwarding link resources. Alternatively, when the first indication information indicates that the target base station does not have the PDU set processing capability, by finding a more suitable new target base station, the capabilities of the two base stations for inter-station switching can be matched, ensuring the QoS guarantee based on PDU set, which is more suitable for the data transmission process based on PDU set. Alternatively, when the first indication information indicates that the target base station does not have the PDU set processing capability, the inter-station switching between the source base station and the target base station can continue to be implemented, thereby avoiding problems such as the terminal being unable to switch in time and causing service interruption. At the same time, the packet header size of the forwarded data is also reduced, thereby reducing the consumption of forwarding link resources.

[0015] In a second aspect, a data transmission method is provided, the method being applied to a source base station where a terminal device is located, the method comprising: sending a first capability query message, the first capability query message being used to query the processing capability of at least one candidate base station for a set of protocol data units (PDUs), the at least one candidate base station to be used in a handover process of the terminal device; receiving second indication information, the second indication information being used to indicate the processing capability of the at least one candidate base station for the set of PDUs; and performing a handover operation based on the second indication information.

[0016] In combination with the second aspect, in certain implementations of the second aspect, performing a switching operation according to the second indication information includes: determining the candidate base station with the processing capability of the PDU set indicated by the second indication information as the target base station in the terminal device switching process.

[0017] In the above technical solution, by understanding the processing capability of at least one candidate base station for PDU set, the candidate base station with PDU set processing capability is used as the target base station during the inter-station switching process, thereby ensuring the QoS requirements of the terminal device based on PDU set.

[0018] In combination with the second aspect, in certain implementations of the second aspect, performing a switching operation according to the second indication information includes: when one of at least one candidate base station is determined as the target base station in the terminal device switching process, if the target base station does not have the processing capability of the PDU set, sending third cache data, and the third cache data does not include relevant information of the PDU set.

[0019] In the above technical solution, even if there is no candidate base station around the source base station that has the processing capability for PDU set, a suitable inter-base station handover strategy can be determined in advance, thereby improving data forwarding efficiency and avoiding resource waste.

[0020] In a third aspect, a data transmission method is provided, the method being applied to a source base station during a handover of a terminal device, the method comprising: sending a fourth handover request, the fourth handover request including a Quality of Service (QoS) parameter of a PDU set; receiving a second feedback message; determining, based on the second feedback message, that a target base station during the handover of the terminal device is a legacy base station, the legacy base station not having processing capabilities for the Protocol Data Unit (PDU) set; and performing a second operation.

[0021] It should be understood that the legacy base station may be the old base station described below.

[0022] In the above technical solution, since the second feedback message does not include indication information of the target base station's processing capability for the PDU set, it can be determined that the target base station is an old base station, that is, an old version base station. Thus, during the inter-station switching process, a data transmission strategy that is more suitable for the old base station is determined, thereby improving data forwarding efficiency and avoiding waste of resources.

[0023] In combination with the third aspect, in some implementations of the third aspect, the QoS parameters include one or more of a protocol data unit set delay budget PSDB, a protocol data unit set error rate PSER, and a protocol data unit set integrity information PSIHI.

[0024] In combination with the third aspect, in certain implementations of the third aspect, performing the second operation includes: sending a fourth cached data packet, the fourth cached data packet does not include relevant information of the PDU set; or, determining a new target base station; or, sending a fifth switching request to the target base station, the fifth switching request does not include QoS parameters of the PDU set.

[0025] In the above technical solution, if the target base station is an older, unupgraded base station (i.e., a legacy base station), inter-station handover can continue to be implemented between the source base station and the older base station, thus avoiding issues such as service interruption caused by delayed terminal handover. This also reduces the size of the forwarded data header, thereby reducing the consumption of forwarding link resources.

[0026] In a fourth aspect, a data transmission method is provided, applied to a first base station, comprising: determining third indication information, the third indication information being used to indicate capability information of the first base station for a low latency, low loss, and scalable throughput (L4S) mechanism. When a trigger condition is met, sending the third indication information to a core network.

[0027] In the above technical solution, the first base station can promptly notify the core network of its L4S support, enabling the core network to understand the first base station's capabilities and select the appropriate method when L4S is required. This helps to promptly adjust the service transmission rate and improve the user experience. For example, if the first base station only supports ECN marking but not congestion reporting, the core network can instruct the first base station to perform ECN marking. If the first base station only supports congestion reporting but not ECN marking, the core network can instruct the first base station to perform congestion reporting and take over the ECN marking work, thus ensuring the normal operation of L4S.

[0028] In combination with the fourth aspect, in some implementations of the fourth aspect, the third indication information is used to indicate whether the first base station has both the explicit congestion notification (ECN) marking capability and the congestion information reporting capability.

[0029] In combination with the fourth aspect, in some implementations of the fourth aspect, the third indication information is used to indicate whether the first base station has ECN marking capability and congestion information reporting capability respectively.

[0030] In combination with the fourth aspect, in some implementations of the fourth aspect, the third indication information is used to indicate whether the first base station has an ECN marking capability or a congestion information reporting capability.

[0031] In conjunction with the fourth aspect, in certain implementations of the fourth aspect, before determining the third indication information, the method further includes: receiving a first capability reporting request, the first capability reporting request being used to request capability information of the first base station for the L4S mechanism. When a trigger condition is met, sending the third indication information includes: sending the third indication information in response to the first capability reporting request.

[0032] In the above technical solution, triggering the third indication information through the capability reporting request allows the core network to obtain the base station's capabilities for the L4S mechanism in a timely manner when needed, thereby helping to determine a more reasonable data transmission strategy.

[0033] In conjunction with the fourth aspect, in certain implementations of the fourth aspect, before determining the third indication information, the method further includes: receiving a first start message, the first start message being used to instruct the first base station to mark an ECN and / or initiate a congestion information reporting operation. When a trigger condition is met, sending the third indication information includes: sending the third indication information when the first base station has or does not have an ECN marking capability and / or a congestion information reporting capability.

[0034] In the above technical solution, triggering the base station to report the third indication information to the core network through a startup message allows the core network to obtain the capabilities of the first base station through less information interaction when determining that the first base station needs to have the capability for the L4S mechanism.

[0035] In conjunction with the fourth aspect, in certain implementations of the fourth aspect, before determining the third indication information, the method further includes: receiving first data, where the first data includes a Quality of Service (QoS) flow for an L4S mechanism. When a trigger condition is met, sending the third indication information includes: sending the third indication information after receiving the first data.

[0036] In the above technical solution, by including the QoS flow for the L4S mechanism in the data, the base station is triggered to actively report the third indication information, so that the core network can obtain the capabilities of the first base station through less information interaction.

[0037] In conjunction with the fourth aspect, in certain implementations of the fourth aspect, before determining the third indication information, the method further includes: receiving a second start message, the second start message being used to instruct the first base station to mark an ECN and / or initiate a congestion information reporting operation. When a trigger condition is met, sending the third indication information includes: sending the third indication information in response to the second start message.

[0038] In some implementations, the second startup information instructs the first base station to mark the uplink data flow or downlink data flow of the first QoS flow or the first DRB in the terminal device with ECN and / or to start a congestion information reporting operation.

[0039] It should be understood that the first QoS flow is any QoS flow in the terminal device, and the first DRB is any DRB in the terminal device.

[0040] In some implementations, the second startup information is used to indicate that the second base station has marked or is marking ECN and / or performing congestion information reporting operations for the uplink data flow or downlink data flow of the second QoS flow or the second DRB in the terminal device.

[0041] It should be understood that the second QoS flow is any QoS flow in the terminal device, and the second DRB is any DRB in the terminal device.

[0042] In some implementations, the second startup information is carried in a third switching request, and the third switching request is used to request the terminal device to switch from the second base station to the first base station.

[0043] In the above technical solution, when switching between stations, triggering the first base station to report the capability for the L4S mechanism helps ensure that when switching from the second base station to the first base station, the data transmission of the terminal device can continue to be transmitted in the manner of the L4S mechanism.

[0044] In certain implementations, the second startup information is carried in a first response message, the first response message being a response to a terminal device context query request message sent by the first base station to the second base station, the first response message being used to indicate the context of the terminal device to the first base station. It should be understood that, before receiving the first response message, the first base station sent a terminal device context query request message to the second base station, the context query request message being used to query the context of the terminal device.

[0045] In combination with the fourth aspect, in certain implementations of the fourth aspect, the method further includes: within the first time period, no third indication information is sent, and the starting moment of the first time period is when the third indication information is sent each time.

[0046] In the above technical solution, by limiting the sending frequency of the third indication information through a preset time length, the two extreme sending methods of frequently sending the third indication information and sending the third indication information once can be avoided, thereby reducing the frequency of capability reporting and ensuring the timeliness and accuracy of capability reporting.

[0047] In a fifth aspect, a data transmission device is provided, comprising a transceiver unit and a processing unit: the transceiver unit is configured to send a first switching request, the first switching request including quality of service (QoS) parameters of a protocol data unit (PDU) set of a terminal device. The transceiver unit is configured to receive first indication information, the first indication information being configured to indicate the processing capability of a target base station for the PDU set during a switching process of the terminal device. The processing unit is configured to perform a switching operation based on the first indication information.

[0048] It should be understood that the beneficial effects corresponding to the scheme of the fifth aspect are similar to those of the first aspect and will not be elaborated here.

[0049] In combination with the fifth aspect, in some implementations of the fifth aspect, the QoS parameters include one or more of a protocol data unit set delay budget PSDB, a protocol data unit set error rate PSER, and a protocol data unit set integrity information PSIHI.

[0050] In combination with the fifth aspect, in certain implementations of the fifth aspect, the processing unit is specifically used to: when the first indication information indicates that the target base station has the processing capability of the PDU set, control the transceiver unit to send a first cache data packet, and the first data cache packet includes relevant information of the PDU set.

[0051] In combination with the fifth aspect, in certain implementations of the fifth aspect, the processing unit is specifically used to: when the first indication information indicates that the target base station does not have the processing capability of the PDU set, control the transceiver unit to send a second cached data packet, and the second cached data packet does not include relevant information of the PDU set; or, determine a new target base station; or, control the transceiver unit to send a second switching request to the target base station, and the second switching request does not include the QoS parameters of the PDU set.

[0052] In a sixth aspect, a data transmission device is provided, comprising a transceiver unit and a processing unit: the transceiver unit is configured to send a first capability query message, the first capability query message being used to query the processing capability of at least one candidate base station for a protocol data unit (PDU) set, and the at least one candidate base station will be used for a terminal device switching process. The transceiver unit is configured to receive second indication information, the second indication information being used to indicate the processing capability of at least one candidate base station for the PDU set. The processing unit is configured to perform a switching operation based on the second indication information.

[0053] It should be understood that the beneficial effects corresponding to the scheme of the sixth aspect are similar to those of the second aspect and will not be elaborated here.

[0054] In combination with the sixth aspect, in certain implementations of the sixth aspect, the processing unit is specifically used to: determine the candidate base station with the processing capability of the PDU set indicated by the second indication information as the target base station in the terminal device switching process.

[0055] In combination with the sixth aspect, in certain implementations of the sixth aspect, the processing unit is specifically used to include: when one of at least one candidate base stations is determined as the target base station in the terminal device switching process, if the target base station does not have the processing capability of the PDU set, controlling the transceiver unit to send third cache data, and the third cache data does not include relevant information of the PDU set.

[0056] In a seventh aspect, a data transmission device is provided, comprising a transceiver unit and a processing unit, wherein the transceiver unit is configured to send a fourth handover request, wherein the fourth handover request includes a quality of service (QoS) parameter of a PDU set. The transceiver unit is configured to receive a second feedback message. The processing unit is configured to determine, based on the second feedback message, that a target base station in a terminal device handover process is an old base station, and that the old base station does not have processing capabilities for a protocol data unit (PDU) set. The processing unit is configured to perform a second operation.

[0057] It should be understood that the beneficial effects corresponding to the solution of the seventh aspect are similar to those of the third aspect and will not be elaborated here.

[0058] In combination with the seventh aspect, in certain implementations of the seventh aspect, the QoS parameters include one or more of a protocol data unit set delay budget PSDB, a protocol data unit set error rate PSER, and a protocol data unit set integrity information PSIHI.

[0059] In combination with the seventh aspect, in certain implementations of the seventh aspect, the processing unit is specifically used to: control the transceiver unit to send a fourth cached data packet, the fourth cached data packet does not include relevant information of the PDU set; or, determine a new target base station; or, control the transceiver unit to send a fifth switching request to the target base station, the fifth switching request does not include the QoS parameters of the PDU set.

[0060] In an eighth aspect, a data transmission device is provided, comprising a processing unit and a transceiver unit. The processing unit is configured to determine third indication information, where the third indication information is configured to indicate capability information of a first base station for a low latency, low loss, and scalable throughput (L4S) mechanism. The transceiver unit is configured to send the third indication information to a core network when a trigger condition is met.

[0061] It should be understood that the beneficial effects corresponding to the scheme of the eighth aspect are similar to those of the fourth aspect and will not be elaborated here.

[0062] In combination with the eighth aspect, in certain implementations of the eighth aspect, the third indication information is used to indicate whether the first base station has both the explicit congestion notification (ECN) marking capability and the congestion information reporting capability.

[0063] In combination with the eighth aspect, in certain implementations of the eighth aspect, the third indication information is used to indicate whether the first base station has ECN marking capability and congestion information reporting capability respectively.

[0064] In combination with the eighth aspect, in certain implementations of the eighth aspect, the third indication information is used to indicate whether the first base station has an ECN marking capability or a congestion information reporting capability.

[0065] In conjunction with the eighth aspect, in certain implementations of the eighth aspect, before the processing unit is configured to determine the third indication information, the transceiver unit is further configured to: receive a first capability reporting request, where the first capability reporting request is used to request capability information of the first base station for the L4S mechanism. The transceiver unit is specifically configured to: send the third indication information in response to the first capability reporting request.

[0066] In conjunction with the eighth aspect, in certain implementations of the eighth aspect, before the processing unit is configured to determine the third indication information, the transceiver unit is further configured to: receive a first startup message, where the first startup message is configured to instruct the first base station to mark an ECN and / or initiate a congestion information reporting operation. The transceiver unit is specifically configured to: send the third indication information when the first base station has or does not have an ECN marking capability and / or a congestion information reporting capability.

[0067] In conjunction with the eighth aspect, in certain implementations of the eighth aspect, before the processing unit is configured to determine the third indication information, the transceiver unit is further configured to: receive first data, where the first data includes a quality of service (QoS) flow for the L4S mechanism. The processing unit is specifically configured to: after receiving the first data, control the transceiver unit to send the third indication information.

[0068] In conjunction with the eighth aspect, in certain implementations of the eighth aspect, before the processing unit determines the third indication information, the transceiver unit is further configured to: receive a second start message, where the second start message is configured to instruct the first base station to mark an ECN and / or initiate a congestion information reporting operation. The transceiver unit is specifically configured to: send the third indication information in response to the second start message.

[0069] In some implementations, the second startup information instructs the first base station to mark the uplink data flow or downlink data flow of the first QoS flow or the first DRB in the terminal device with ECN and / or to start a congestion information reporting operation.

[0070] It should be understood that the first QoS flow is any QoS flow in the terminal device, and the first DRB is any DRB in the terminal device.

[0071] In some implementations, the second startup information is used to indicate that the second base station has marked or is marking ECN and / or performing congestion information reporting operations for the uplink data flow or downlink data flow of the second QoS flow or the second DRB in the terminal device.

[0072] It should be understood that the second QoS flow is any QoS flow in the terminal device, and the second DRB is any DRB in the terminal device.

[0073] In some implementations, the second startup information is carried in a third switching request, and the third switching request is used to request the terminal device to switch from the second base station to the first base station.

[0074] In certain implementations, the second startup information is carried in a first response message, the first response message being a response to a terminal device context query request message sent by the first base station to the second base station, the first response message being used to indicate the context of the terminal device to the first base station. It should be understood that, before receiving the first response message, the first base station sent a terminal device context query request message to the second base station, the context query request message being used to query the context of the terminal device.

[0075] In combination with the eighth aspect, in certain implementations of the eighth aspect, the method further includes: within the first time period, no third indication information is sent, and the starting moment of the first time period is when the third indication information is sent each time.

[0076] In the ninth aspect, a data transmission device is provided, which includes: a memory for storing programs; a processor for executing computer programs or instructions stored in the memory, and when the computer program or instructions stored in the memory are executed, the processor is used to execute the method provided in any one of the implementations of the first or fifth aspects above.

[0077] In one implementation, the apparatus is a source base station during a terminal device switching process.

[0078] In another implementation, the device is a chip, chip system or circuit in a source base station during the terminal device switching process.

[0079] In the tenth aspect, the present application provides a processor for executing the method provided by any one of the implementation methods of the first to fourth aspects above. In the process of executing these methods, the process of sending the above information and obtaining / receiving the above information in the above method can be understood as the process of the processor outputting the above information, and the process of the processor receiving the input above information. When outputting the above information, the processor outputs the above information to the interface and transmits it through the interface. After being output by the processor, the above information may also need to undergo other processing before reaching the interface. Similarly, when the processor receives the input above information, the interface obtains / receives the above information and inputs it into the processor. Furthermore, after the interface receives the above information, the above information may need to undergo other processing before being input into the processor.

[0080] For the operations involved, such as transmission, sending, and acquisition / reception, unless otherwise specified, or if they do not conflict with their actual functions or internal logic in the relevant descriptions, they can be understood as output and reception, input and other operations, and can also be understood as transmission, sending and receiving operations performed by radio frequency circuits and antennas. This application does not limit this.

[0081] During implementation, the processor may be a processor specifically configured to execute the methods, or may be a processor that executes computer programs or instructions in a memory to execute the methods, such as a general-purpose processor. The memory may be a non-transitory memory, such as a read-only memory (ROM), which may be integrated with the processor on the same chip or disposed on separate chips. The embodiments of the present application do not limit the type of memory or the configuration of the memory and the processor.

[0082] In the eleventh aspect, a computer-readable storage medium is provided, which stores a program code for execution by a device, and the program code includes a method for executing any one of the implementation methods of the first to fourth aspects above.

[0083] In a twelfth aspect, a computer program product comprising instructions is provided, which, when run on a computer, enables the computer to execute the method provided in any one of the implementations of the first to fourth aspects above.

[0084] In the thirteenth aspect, a chip is provided, which includes a processor and a communication interface. The processor reads instructions stored in the memory through the communication interface and executes the method provided in any one of the implementation methods of the first to fourth aspects above.

[0085] Optionally, as an implementation method, the chip may also include a memory, in which a computer program or instruction is stored, and the processor is used to execute the computer program or instruction stored in the memory. When the computer program or instruction is executed, the processor is used to execute the method provided in any one of the implementation methods of the first to fourth aspects above. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] FIG1 is a schematic diagram of a communication system provided in an embodiment of the present application;

[0087] FIG2 is a schematic diagram of a 5G system based on a QoS architecture provided in an embodiment of the present application;

[0088] FIG3 is a schematic diagram of a flow chart of an inter-station handover process provided by an embodiment of the present application;

[0089] FIG4 is a schematic diagram of a process for inter-station handover of an XR service provided in an embodiment of the present application;

[0090] FIG5 is a flow chart of a data transmission method provided in an embodiment of the present application;

[0091] FIG6 is a flow chart of another data transmission method provided in an embodiment of the present application;

[0092] FIG7 is a flow chart of another data transmission method provided in an embodiment of the present application;

[0093] FIG8 is a schematic diagram of a behavior flow of a target base station provided in an embodiment of the present application;

[0094] FIG9 is a schematic diagram of a behavior flow of a source base station provided in an embodiment of the present application;

[0095] FIG10 is a flow chart of another data transmission method provided in an embodiment of the present application;

[0096] FIG11 is a flow chart of another data transmission method provided in an embodiment of the present application;

[0097] FIG12 is a schematic diagram of the operation mode of the L4S mechanism provided in an embodiment of the present application;

[0098] FIG13 is a flow chart of another data transmission method provided in an embodiment of the present application;

[0099] FIG14 is a schematic diagram of a data transmission device 1400 provided in an embodiment of the present application;

[0100] FIG15 is a schematic structural diagram of a data transmission device 1500 provided in an embodiment of the present application;

[0101] FIG16 is a schematic diagram of a chip system 1600 provided in an embodiment of the present application. DETAILED DESCRIPTION

[0102] The technical solution in this application will be described below with reference to the accompanying drawings.

[0103] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: Global System of Mobile communication (GSM) system, Code Division Multiple Access (CDMA) system, Wideband Code Division Multiple Access (WCDMA) system, General Packet Radio Service (GPRS), Long Term Evolution (LTE) system, LTE Frequency Division Duplex (FDD) system, LTE Time Division Duplex (TDD), Universal Mobile Telecommunication System (UMTS), Worldwide Interoperability for Microwave Access (WiMAX) communication system, Fifth Generation (5G) system or New Radio (NR), and future evolved communication systems.

[0104] FIG1 is a schematic diagram of a communication system provided in an embodiment of the present application.

[0105] As shown in Figure 1, a communication system using the solution of an embodiment of the present application may include an access network device, a terminal device, and a core network. The communication system can be used for information exchange between an access network device and a core network, or for information exchange between access network devices. For example, as shown in Figure 1, both access network device #1 and access network device #2 can communicate with the core network via an NG interface. Access network device #1 and access network device #2 can communicate directly via an Xn interface, or access network device #1 and access network device #2 can communicate indirectly via the core network via the NG interface.

[0106] Terminal equipment, also known as user equipment (UE), mobile station (MS), mobile terminal (MT), etc., refers to a device that provides voice and / or data connectivity to users. For example, a terminal device can be a mobile phone, a tablet computer (Pad), a computer with wireless transceiver function, a mobile internet device (MID), a wearable device, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, a drone, a drone controller, etc. The embodiments of the present application do not limit the application scenarios. Terminal devices also include devices capable of sidelink communication, such as vehicle-mounted terminals, or handheld terminals capable of V2X (vehicle-to-everything) communication.

[0107] Access network equipment refers to a radio access network (RAN) node (or device) that connects a terminal to a wireless network, and can also be called a base station. For example, it can be an NR gNB, or various types of base stations such as an LTE eNB. For ease of description, the embodiments of this application uniformly refer to "access network equipment" as "base station". Among them, the NR gNB can adopt an architecture with a centralized unit (CU) and a distributed unit (DU) separated, such as base station #1 shown in Figure 1, where the CU and DU are connected via the F1 interface for message transmission; or the architecture with no separation of CU and DU can be adopted, such as base station #2 shown in Figure 1, which is not limited in this embodiment of the application. In the separate deployment scenario where the access network equipment includes a CU and a DU, the CU supports protocols such as radio resource control (RRC), packet data convergence protocol (PDCP), and service data adaptation protocol (SDAP); the DU mainly supports radio link control layer (RLC), media access control layer (MAC), and physical layer protocols. Normally, a terminal device maintains a data connection with only one base station at a time. In a dual connectivity (DC) scenario, a terminal device can be connected to two base stations simultaneously, one of which serves as a control anchor point, providing both control and user plane connections for the terminal, known as a primary base station, and the other, which only provides user plane connections for the terminal, known as a secondary base station. This application may or may not be applied to DC scenarios.

[0108] Core network equipment refers to the equipment in the core network (CN) that provides service support for the terminal. At present, some examples of core network equipment are: access and mobility management function (AMF) entity, session management function (SMF) entity, user plane function (UPF) entity, etc., which are not listed here one by one. Among them, the AMF entity can be responsible for the access management and mobility management of the terminal; the SMF entity can be responsible for session management, such as user session establishment, etc.; the UPF entity can be a functional entity of the user plane, mainly responsible for connecting to the external network. It should be noted that the entity in this application can also be referred to as a network element or a functional entity. For example, the AMF entity can also be referred to as an AMF network element or an AMF functional entity. For another example, the SMF entity can also be referred to as an SMF network element or an SMF functional entity, etc.

[0109] In order to facilitate understanding of the solutions of the embodiments of the present application, the technical terms involved in the embodiments of the present application will be described in detail below.

[0110] 1.PDU set

[0111] A collection of multiple data packets at the transport layer corresponds to the minimum granularity of data processing at the application layer. In some scenarios, the application layer can only correctly parse the corresponding data unit after correctly receiving all packets in a PDU set. In other scenarios, the application layer can only parse the corresponding data unit after correctly receiving a certain percentage of packets in the PDU set.

[0112] 2.XR business

[0113] Extended Reality (XR) refers to a variety of environments that combine real and virtual reality, as well as human-machine interactions, generated by computing technologies and wearable devices. XR specifically includes the following typical forms: AR, VR, and Mixed Reality (MR).

[0114] The 3rd Generation Partnership Project (3GPP) Rel-17 modeled and analyzed XR service characteristics. XR services typically generate data frames periodically at a certain frame rate. For example, an AR service with a 60fps (frames per second) frame generates 60 frames per second, or approximately every 16.67ms. A single video frame may be transmitted across multiple data packets, which may be grouped into one or more PDU sets.

[0115] 3. Quality of Service (QoS)

[0116] Quality of Service (QoS) refers to a technology used to address network latency and congestion. When network congestion occurs, data may be discarded. To meet user requirements for different QoS levels for different applications, the network must be able to allocate and schedule resources based on user needs, providing different QoS levels for different data types.

[0117] 4. QoS flow

[0118] The 5G system forwards and processes data based on the granularity of QoS flows and guarantees its QoS.

[0119] The 5G core network establishes one or more protocol data unit sessions (PDU sessions) for a UE. A QoS flow is a data flow with the same source and destination addresses and the same QoS requirements within a PDU session. Figure 2 is a schematic diagram of a 5G system based on a QoS architecture provided by an embodiment of the present application. As shown in Figure 2, a PDU session is established between the UE and the UPF, a radio bearer is established between the UE and the NB, and a core network tunnel is established between the NB and the UPF. The PDU session includes multiple QoS flows, including a first QoS flow, a second QoS flow, and the like.

[0120] For downlink, 5GC identifies the characteristics of the data packet, including the source Internet Protocol (IP) address, destination IP address, source port number, destination port number, and transport layer protocol number, and maps data packets with the same characteristics to the same QoS flow. It also carries a QoS flow identifier (QFI) in the packet header to identify which QoS flow the packet belongs to. For uplink, 5GC can explicitly or implicitly configure the mapping relationship between the above data packet characteristics and QoS flows to the UE, and the UE will map the uplink data to be transmitted to different QoS flows.

[0121] Data from different QoS flows is transmitted independently within the 5G system. For each QoS flow, the 5GC sends its QoS profile to the radio access network (RAN). This profile indicates its QoS requirements, such as the packet delay budget (PDB) and packet error rate (PER). This profile represents the expected quality of service for data transmitted within the 5G system. The PDB represents the upper limit of the transmission delay between the core network and the UE. Packets that fail to transmit correctly within the PDB are considered timed out. The PER represents the upper limit of the packet error rate during QoS flow transmission—the percentage of packets processed by the sender but not correctly received by the receiver. Specifically, the core network and the UE can be understood as, for downlink traffic, traffic from the core network's UPF to the UE; for uplink traffic, traffic from the UE to the core network's UPF.

[0122] For a PDU session, the RAN establishes one or more data radio bearers (DRBs) and maps each QoS flow to these DRBs for air interface transmission. Multiple QoS flows can be mapped to a single DRB, but a single QoS flow cannot be mapped to multiple DRBs. QoS flows with the same or similar QoS requirements are typically mapped to the same DRB, providing the same QoS guarantees over the air interface.

[0123] 5. QoS parameters of PDU

[0124] The 5GC uses QoS profiles to indicate the QoS requirements of different QoS flows to the RAN. These requirements are reflected in various QoS parameters. For example, common QoS parameters include PDB and PER. The transport network should strive to ensure that service QoS requirements are met to enhance user experience.

[0125] 6. QoS parameters for PDU set

[0126] XR services typically require QoS guarantees at the PDU set level, which is determined by the encoding method used for XR services. Because a PDU set corresponds to the smallest unit of application-layer data processing, such as a video frame, for many applications, the receiving end can only successfully decode the video frame if all packets in the PDU set are correctly received. Therefore, XR services require the transmission network to provide overall QoS guarantees for the PDU set to prevent partial packet timeouts or errors within the PDU set from causing decoding failures of the entire video frame.

[0127] 3GPP R18 (Release-18) designed new QoS parameters for XR services, called PDU set QoS parameters, including PDU set delay budget (PSDB), PDU set error rate (PSER), and PDU set integrated information (PSIHI). PSDB and PSER correspond to the traditional PDB and PER, respectively. PSDB represents the upper limit of the delay from the transmission of the first data packet in the PDU set between the core network and the UE to the completion of the transmission of the last data packet in the PDU set between the core network and the UE, that is, the upper limit of the transmission delay of the PDU set between the core network and the UE. A PDU set that is not correctly transmitted in full within the PSDB is considered to have timed out. PSER represents the upper limit of the percentage of PDU sets that are not correctly transmitted during the transmission of the QoS flow, that is, the upper limit of the percentage of PDU sets that are processed by the sender but not correctly received by the receiver. PSIHI describes whether a QoS flow requires PDU set integrity. It indicates whether the application layer, when processing a PDU set, requires the receiving side to correctly receive all packets within the PDU set. This depends on the specific implementation of the application.

[0128] In one implementation, an application can only correctly decode a PDU set after correctly receiving all packets within it. In this case, the transmission network should strive to ensure that all packets within the PDU set are correctly transmitted within the delay budget. If a packet times out or is lost, the receiving application layer will not be able to process the PDU set in a timely manner, resulting in a poor user experience. If it is determined that a packet in the PDU set cannot be transmitted correctly and in a timely manner, the sender can abandon transmission of the remaining packets. Even if the remaining packets are correctly transmitted, the application cannot process them, and proactively abandoning transmission can save network resources. In another implementation, an application does not need to correctly receive all packets within a PDU set to decode the set. For example, when a PDU set has been redundantly encoded at the sender, the receiver can fully recover the PDU set data by receiving only a certain number or proportion of packets. In this case, even if some packets within the PDU set have timed out or been lost, the sender should continue to transmit the remaining packets, as they are still useful to the application layer.

[0129] Through PDU set QoS parameters, the core network requires the RAN to provide PDU set-granular QoS guarantees for PDU set-based QoS flows (such as XR services), thereby improving XR user satisfaction.

[0130] 7. Handover

[0131] In mobile communication systems, when a UE obtains service from a 5G network, it may need to change its serving cell due to a change in location. The process of a connected UE changing its serving cell is called a handover. The handover process is controlled by the base station, which sends a handover message to instruct the UE when and which cell to switch to. The base station typically determines whether to switch and to which cell based on the signal quality of each cell.

[0132] When the source cell (i.e., the cell where the UE originally resides) and the target cell (i.e., the cell to which the UE is switching) are located in different base stations, this type of handover is called an inter-base station handover. Depending on the type of interface between the source and target base stations, this type of handover can be categorized as either Xn or NG.

[0133] FIG3 is a schematic diagram of a flow chart of an inter-station handover process provided in an embodiment of the present application.

[0134] As shown in FIG3( a ), when an Xn interface exists between the source base station and the target base station, handover based on the Xn interface can be performed.

[0135] S311, the source base station sends a handover request (HANDOVER REQUEST) #1 to the target base station.

[0136] Handover Request #1 indicates that the UE wishes to handover to the target cell. The Handover Request carries the UE's configuration requirements, such as the PDU session and QoS flows established by the UE, as well as the QoS requirements of these QoS flows.

[0137] S312: The target base station performs admission control based on the cell load, capability, etc., and determines the handover request feedback message #1.

[0138] The handover request feedback message #1 is used to indicate whether to accept the handover UE and which PDU sessions or QoS flows of the UE are accepted.

[0139] It should be understood that when the target base station agrees to handover request #1, the type of handover request feedback message #1 is a handover request acknowledgment message (HANDOVER REQUEST ACKNOWLEDGE). When the target base station disagrees with handover request #1, the type of handover request feedback message #1 is a handover preparation failure message (HANDOVER PREPARATION FAILURE).

[0140] S313: The target base station sends a handover request feedback message #1 to the source base station.

[0141] S314: If the target base station accepts the handover of the UE, the source base station sends a handover command #1 to the UE, wherein the handover command #1 is used to instruct the UE to access the target cell.

[0142] S315: The source base station stops transmitting data with the UE and sends the buffered data #1 to the target base station.

[0143] The cached data #1 is the data that is already in the source base station cache and should be sent to the UE.

[0144] S316: After receiving the instruction, the UE performs handover and successfully accesses the target cell.

[0145] S317, the terminal device and the target base station complete access to the target cell.

[0146] That is, the terminal device continues to transmit data in the target cell, that is, the core network sends subsequent downlink data to the UE through the target base station, and the UE's uplink data is also sent to the core network through the target base station.

[0147] As shown in (b) of Figure 3, when there is no Xn interface between the source base station and the target base station, the base stations cannot directly transmit the switching request and confirmation messages. At this time, a switching based on the NG interface is required to forward the above messages through the core network.

[0148] S321a, the source base station sends a handover request #2 to the core network. S321b, the core network sends a handover request #3 to the target base station.

[0149] Among them, the functions and effects of switching request #2, switching request #3 and switching request #1 are similar and will not be described in detail here.

[0150] S322: The target base station performs admission control based on the cell load, capability, etc., and determines a handover request feedback message #2.

[0151] Among them, the handover request feedback message #2 has similar functions to the handover request feedback message #1, and will not be described in detail here.

[0152] S323, the target base station sends a handover request feedback message #2 to the core network.

[0153] S324a, when the target base station accepts the handover UE, the core network sends a handover command #2 to the source base station. S324b, the source base station sends a handover command #3 to the terminal device.

[0154] The handover command #2 is used to instruct the source base station to continue the handover operation, and the handover command #3 is used to instruct the UE to handover to the target cell.

[0155] S325a: The source base station stops transmitting data to the UE and sends the buffered data #2 to the core network. S325b: The core network sends the buffered data #2 to the target base station.

[0156] The cached data #2 is data that is already in the source base station cache and should be sent to the UE.

[0157] S326: After receiving the instruction, the UE performs handover and successfully accesses the target cell.

[0158] S327, the terminal device and the target base station complete access to the target cell.

[0159] That is, the terminal device continues to transmit data in the target cell, that is, the core network sends subsequent downlink data to the UE through the target base station, and the UE's uplink data is also sent to the core network through the target base station.

[0160] It should be understood that the information transmission method between the source base station and the target base station can be to realize direct communication between the source base station and the target base station through the Xn interface, or to realize indirect communication between the source base station and the target base station through the NG interface and forwarding through the core network.

[0161] At present, since XR services require QoS guarantee based on the granularity of PDU set, the corresponding base stations need to support data processing and forwarding based on PDU set. Furthermore, during downlink transmission, when the QoS flow requires QoS guarantee based on PDU set and the base station supports PDU set processing, the core network will add relevant information of PDU set to the header of each data packet when transmitting the data packet to the base station. The relevant information can be a parameter used to identify the PDU set or reflect the attributes of the PDU set. For example, the PDU set sequence number, the sequence number of the PDU in the PDU set, the PDU set size, the PDU set importance, etc., so that the base station can distinguish which PDU set different data packets belong to. If the base station does not support PDU set processing, the core network does not need to add this information. Therefore, the core network needs to know the capability information of whether the base station supports PDU set processing.

[0162] Specifically, if the base station receives a QoS profile of a QoS flow containing QoS parameters of a PDU set, the base station reports to the core network whether it supports processing the PDU set.

[0163] FIG4 is a flow chart of an inter-station handover of an XR service provided by an embodiment of the present application. Assume that the source base station in FIG4 supports processing PDU sets, and the target base station does not support processing PDU sets. The terminal device is running an XR service (for example, receiving XR video from an XR server) and expects that the data of the XR service can obtain QoS guarantees based on PDU sets. Among them, the source base station and the target base station shown in FIG4 can communicate directly through the Xn interface.

[0164] S401: The core network sends a QoS guarantee requirement of a PDU set to a source base station.

[0165] The QoS guarantee requirement may include a QoS profile of the QoS parameters of the PDU set.

[0166] S402: The source base station sends capability indication information to the core network according to the QoS configuration file. The capability indication information is used to indicate that the source base station has the capability to process PDU sets.

[0167] S403: The core network sends first XR data to the source base station, where the first XR data includes relevant information of the PDU set.

[0168] The relevant information of the PDU set may be carried in the header of the data packet in the QoS flow where the first XR data is located. The relevant information of the PDU set may include, for example, the PDU set sequence number, the sequence number of the PDU within the PDU set, the PDU set end identifier, the data burst end identifier, the PDU set size, the PDU set importance, etc.

[0169] S404: The source base station processes the first XR data according to the relevant information of the PDU set.

[0170] It should be understood that the source base station identifies the relevant information of the PDU set in the first XR data to determine which PDU set the first XR data corresponds to, and provides scheduling processing based on the PDU set to ensure its PDU set QoS requirements. The relevant information of the PDU set has been described in detail above and will not be repeated here.

[0171] S405: The source base station sends the processed first XR data to the terminal device.

[0172] The terminal device is currently in the source cell of the source base station. Assuming that the terminal device moves, the terminal device expects to switch to the target cell of the target base station.

[0173] S406 : The source base station sends a handover request # 3 to the target base station. The handover request # 3 includes a QoS profile of the QoS flow where the first XR data is located, including QoS parameters of a PDU set.

[0174] S407: When the target base station does not support processing the PDU set, the target base station sends capability indication information to the core network. The capability indication information is used to indicate that the target base station does not support processing the PDU set.

[0175] It should be understood that the core network device's knowledge of the capability indication information of the target base station helps the core network to send data to the target base station in a more targeted manner.

[0176] S408: The target base station performs admission control based on the cell load, capability, etc., and determines the handover request feedback message #3.

[0177] Among them, the handover request feedback message #3 and the handover request feedback message #1 have similar functions and are not described in detail here.

[0178] S409: The source base station sends a handover command #3 to the UE, wherein the handover command #3 is used to instruct the UE to access the target cell.

[0179] S410: The source base station stops transmitting data with the UE and sends the buffered data #3 to the target base station.

[0180] The buffered data #3 is the first XR data that has been buffered in the source base station. Therefore, the data packet header of the buffered data #3 carries relevant information of the PDU set.

[0181] S411, the terminal device and the target base station complete access to the target cell.

[0182] S412: The target base station sends a handover completion message to the core network.

[0183] S413: The core network sends second XR data to the target base station. The second XR data does not include relevant information of the PDU set.

[0184] It should be understood that since the target base station does not support processing PDU sets, the data transmission between the core network and the target base station falls back to the traditional PDU-based transmission mode. In other words, the second XR data includes information related to the PDU, rather than information related to the PDU set.

[0185] S414: The target base station processes the second XR data according to the relevant information of the PDU.

[0186] S415: The target base station sends the processed second XR data to the terminal device.

[0187] The variability in base station support for PDU set processing is primarily due to variations in base station capabilities and upgrade status in real-world networks. While the aforementioned solution takes into account the potential differences in base station support for PDU set processing and incorporates a mechanism for base stations to notify the core network of this capability, enabling the core network to rationally decide whether to provide PDU set-based QoS guarantees for a QoS flow and whether to add PDU set information to packets within the QoS flow, before data can be transmitted between the target base station and the terminal device, the data originally buffered at the source base station must be forwarded to the target base station. This can lead to a mismatch between the buffered data and the target base station's capabilities, as shown in Figure 4. Consequently, the PDU set information carried in the buffered data's packet header may be useless to the target base station, while consuming forwarding link resources (e.g., Xn or NG links), resulting in wasted resources. Furthermore, the target base station may not understand the meaning of this information, leading to confusion or misunderstanding, resulting in unexpected errors.

[0188] To address the above issues, embodiments of the present application provide a data transmission method and apparatus, which will be described in detail below with reference to FIG5 to FIG15.

[0189] Figure 5 is a flow chart of a data transmission method provided in an embodiment of the present application, which is applied to a source base station during a handover of a terminal device.

[0190] S510: The source base station sends a first handover request, where the first handover request includes QoS parameters of a PDU set.

[0191] The QoS parameters include one or more of the following: protocol data unit set delay budget (PSDB), protocol data unit set error rate (PSER), and protocol data unit set integrity information (PSIHI). It should be understood that the specific meanings of these parameters have been given above and will not be repeated here.

[0192] As a possible implementation manner, the source base station directly sends the first switching request to the target base station in the terminal device switching process through the Xn interface.

[0193] As a possible implementation method, the source base station sends a first switching request to the core network through the NG interface. The core network can send the first switching request to the target base station through the NG interface, or the core network can send the processed first switching request to the target base station through the NG interface.

[0194] S520, the source base station receives first indication information, where the first indication information is used to indicate the processing capability of the target base station for the PDU set during the terminal device switching process.

[0195] As a possible implementation manner, the source base station may directly receive the first indication information from the target base station through an Xn interface.

[0196] As a possible implementation manner, the target base station may send the first indication information to the core network through the NG interface, and the core network sends the first indication information to the source base station through the NG interface.

[0197] It should be understood that the first indication information can be in an independent message or carried in a first feedback message in response to the first handover request. This embodiment of the present application does not limit this, and the details will be described in detail in FIG6 .

[0198] S530: The source base station performs a handover operation according to the first instruction information.

[0199] As a possible implementation manner, when the first indication information indicates that the target base station has the processing capability of the PDU set, the source base station sends a first buffered data packet, where the first buffered data packet includes relevant information of the PDU set.

[0200] It should be understood that the relevant information of the PDU set has been described in detail in the above content and will not be repeated here.

[0201] As a possible implementation method, when the first indication information indicates that the target base station does not have the processing capability of the PDU set, a second cached data packet is sent, and the second cached data packet does not include relevant information of the PDU set; or, a new target base station is determined; or, a second switching request is sent to the target base station, and the second switching request does not include the QoS parameters of the PDU set.

[0202] In the above technical solution, the source base station fully considers the processing capability of the target base station for PDU set and makes reasonable switching decisions, thereby avoiding the waste of link resources and even data decoding errors caused by the mismatch between the processing capabilities of the two base stations for PDU set. For example, if the target base station does not support PDU set processing, and there are other optional switching base stations in the surrounding area, in order for the terminal device to continue to enjoy the QoS guarantee based on PDU set, the source base station can try to switch to other base stations. Even if the terminal device has no other choice but to switch to the current target base station, the source base station can also optimize the forwarded data packets during subsequent cache data forwarding, remove the PDU set information carried in its packet header, thereby reducing resource consumption on the forwarding link and improving forwarding efficiency.

[0203] A more specific implementation manner in which the source base station learns whether other base stations have the PDU set processing capability will be described in detail below with reference to FIG. 6 to FIG. 11 .

[0204] Figure 6 is a flow chart of another data transmission method provided by an embodiment of the present application. The interaction diagram shown in Figure 6 takes the source base station and the target base station in the terminal device switching process as the execution subject of the interaction diagram as an example to illustrate the corresponding method, but the present application does not limit the execution subject of the interaction diagram. For example, the source base station in Figure 6 may also be a chip, a chip system or a processor that supports the source base station to implement the corresponding method, or a logic module or software that can implement all or part of the functions of the source base station. The target base station in Figure 6 may also be a chip, a chip system or a processor that supports the target base station to implement the corresponding method, or a logic module or software that can implement all or part of the functions of the target base station.

[0205] S601: A source base station sends a first handover request to a target base station, where the first handover request includes QoS parameters of a PDU set.

[0206] The first handover request is used to request the terminal device to handover from the source base station to the target base station. It should be understood that the terminal device requires QoS guarantee based on PDU set.

[0207] It should be understood that the specific content of the QoS parameters of the PDU set has been described in detail above. The QoS parameters of the PDU set may include one or more of the PDU set delay budget PSDB, the PDU set error rate PSER, and the PDU set integrity information PSIHI.

[0208] S602: The target base station performs admission control in response to the first handover request.

[0209] It should be understood that after admission control, the target base station has confirmed the information related to the first handover request.

[0210] The information related to the first handover request may include at least one of the following information: whether the first handover request is approved, whether the QoS flow is accepted, and whether the processing capability of the PDU set is available.

[0211] The QoS flow is a QoS flow with a QoS requirement of a PDU set.

[0212] It should be understood that when determining whether to approve the first handover request and / or whether to accept the QoS flow, the target base station may not consider the target base station's processing capability for the PDU set. For example, only the target base station's current load and / or current resource usage may be considered. Alternatively, the target base station may also consider its processing capability for the PDU set when determining whether to approve the first handover request and / or whether to accept the QoS flow.

[0213] Method 1: The target base station sends the indication information of whether it has the processing capability of the PDU set through a separate message.

[0214] S603a-1. The target base station sends first indication information to the source base station. The first indication information is used to indicate the processing capability of the target base station for the PDU set.

[0215] In other words, the first indication information is used to indicate whether the target base station has the processing capability of the PDU set.

[0216] S603a-2: The target base station sends a first feedback message to the source base station, where the first feedback message indicates whether the first handover request is approved. Optionally, the first feedback message may also indicate whether the QoS flow is accepted.

[0217] The QoS flow is a QoS flow with a QoS requirement of a PDU set.

[0218] As a possible implementation, when the message type of the first feedback message is a handover request confirmation message, the first feedback message is used to indicate approval of the first handover request. When the message type of the first feedback message is a handover preparation failure message, the first feedback message is used to indicate disapproval of the first handover request.

[0219] It should be understood that the embodiments of the present application do not limit the execution order of S603a-1 and S603a-2. For example, S603a-1 may be executed first, and then S603a-2. For another example, S603a-2 may be executed first, and then S603a-1. In this example, the target base station may first execute S603a-2 based on factors other than the PDU set processing capability. For example, the current load or currently available resources of the target base station determine the indication information of the first feedback message, for example, determine whether the first feedback message agrees with the first switching request. Then, when the first feedback message indicates agreement with the first switching request or disagreement with the first switching request, S603a-1 is executed.

[0220] Method 2: The target base station carries indication information of whether it has the processing capability of the PDU set in the first feedback message.

[0221] S603b: The target base station sends a first feedback message to the source base station. The first feedback message includes first indication information. The first indication information is used to indicate whether the target base station has the processing capability of the PDU set.

[0222] Optionally, for other specific information indicated in the first feedback message, reference may be made to S603a-2, which will not be elaborated here.

[0223] As a possible implementation, the first indication information is used to indicate that the target base station has the capability to process the PDU set, i.e., the target base station supports PDU set processing. The first feedback message is used to indicate that the target base station agrees to the first handover request. Optionally, the first feedback message is also used to indicate that the target base station accepts the QoS flow.

[0224] For example, the first indication information may include an indication field. When the indication field is a first value, the first indication information is used to indicate that the target base station has the processing capability of the PDU set. The embodiment of the present application does not impose any restrictions on the specific value of the first value. The source base station and the target base station have the same meaning for the value of the first value.

[0225] As a possible implementation, the first indication information is used to indicate that the target base station does not have the processing capability of the PDU set, that is, the target base station does not support PDU set processing. The first feedback message is used to indicate that the target base station agrees to the first handover request. Optionally, the first feedback message is also used to indicate that the target base station accepts the QoS flow.

[0226] As a possible implementation, the first indication information is used to indicate that the target base station does not have the processing capability of the PDU set, that is, the target base station does not support PDU set processing. The first feedback message is used to indicate that the target base station agrees to the first handover request. Optionally, the first feedback message is also used to indicate that the target base station does not accept the QoS flow.

[0227] Exemplarily, the first indication information is used to indicate that the target base station does not have the processing capability of the PDU set, that is, the target base station does not support PDU set processing. The first feedback message is used to indicate that the target base station agrees to the first handover request. The first feedback message is also used to indicate that the target base station does not accept the QoS flow.

[0228] The reason why the target base station does not accept the QoS flow is that the target base station does not support PDU set processing.

[0229] For example, the first indication information may include an indication field. When the indication field is a second value, the first indication information is used to indicate that the target base station does not have the processing capability of the PDU set. The embodiment of the present application does not impose any restrictions on the specific value of the second value, and the meaning corresponding to the value of the second value taken by the source base station and the target base station is consistent.

[0230] For another example, the first feedback message may include a QoS flow not admitted list, and the QoS flow not admitted list may include a quality of service flow identity (QFI) corresponding to the QoS flow not admitted. The QoS flow not admitted list may also include a first cause field, and the first cause field may be a first indication information. When the first cause field is a third value, the first cause field is used to indicate that the target base station does not have the processing capability of the PDU set. In this case, the first indication information is carried in the first feedback message, and the cause field is a possible specific form of expression of the first indication information. It should also be understood that the embodiment of the present application does not impose any restrictions on the value of the third value, and the corresponding meanings of the value of the third value for the source base station and the target base station are consistent.

[0231] In the case where the target base station agrees to the first handover request, the first feedback message may also be referred to as a first handover request confirmation message, that is, the type of the first feedback message is a handover request confirmation message.

[0232] In one possible implementation, the first indication information is used to indicate that the target base station does not have the processing capability of the PDU set, that is, the target base station does not support PDU set processing. The first feedback message is used to indicate that the target base station does not agree to the first handover request. Optionally, the first feedback message is also used to indicate that the target base station does not accept the QoS flow.

[0233] In the case that the target base station does not agree to the first handover request, the first feedback message may also be referred to as a first handover preparation failure message. That is, the type of the first feedback message is a handover preparation failure message.

[0234] For example, the first handover preparation failure message includes a second cause field, and the second cause field can be the first indication information. When the second cause field is the fourth value, the second cause field is used to indicate that the target base station does not have the processing capability of the PDU set. In this case, the first indication information is carried in the first feedback message, and the cause field is a possible specific form of expression of the first indication information. It should also be understood that the embodiment of the present application does not impose any restrictions on the value of the fourth value, and the meaning corresponding to the value of the fourth value of the source base station and the target base station is consistent.

[0235] For another example, the first indication information may include an indication field. When the indication field is a second value, the first indication information is used to indicate that the target base station does not have the processing capability of the PDU set.

[0236] It should be understood that in the above S603a-1, S603a-2 or S603b, part or all of the information related to the first handover request is made known to the source base station.

[0237] It should also be understood that the above S603a-1, S603a-2, or S603b is based on the example of communication between the source base station and the target base station via the Xn interface. The target base station can also transmit the information in S603a-1, S603a-2, or S603b to the source base station via the core network via the NG interface. This implementation is not shown in the accompanying drawings. For specific interaction methods, please refer to Figure 3 (b).

[0238] S604: The source base station performs a first operation according to the first instruction information.

[0239] The first operation can be understood as a handover operation related to inter-station handover. S604a to S604d are four possible first operations.

[0240] As a possible implementation manner, when the first indication information indicates that the target base station has the processing capability of the PDU set, S604a may be executed.

[0241] As a possible implementation manner, when the first indication information indicates that the target base station does not have the processing capability of the PDU set, S604b, S604c or S604d may be executed.

[0242] In the above technical solution, the source base station fully considers the processing capability of the target base station for the PDU set, thereby avoiding the waste of link resources and even data decoding errors caused by the mismatch between the processing capabilities of the two base stations for the PDU set.

[0243] First operation #1: S604a, the source base station sends first buffered data to the target base station, where the first buffered data includes relevant information of the PDU set.

[0244] For example, the execution condition of the first operation #1 may be that the first indication information indicates that the target base station has the PDU set processing capability. Alternatively, the execution condition may also be that the first indication information indicates that the target base station has the PDU set processing capability, the first feedback message indicates that the target base station agrees to the first handover request, and the first feedback message is also used to indicate the acceptance of the QoS flow.

[0245] In this way, when the first indication information indicates that the target base station has the PDU set processing capability, the source base station directly forwards the cached data to be forwarded to the target base station. Compared with the source base station directly forwarding the cached data to the target base station when the capability of the target base station is unknown, the solution of the present application can ensure that there is no waste of link resources when forwarding the cached data.

[0246] First operation #2: S604b, the source base station sends second buffered data to the target base station, where the second buffered data does not include relevant information of the PDU set.

[0247] Before sending the second buffered data, the source base station removes the PDU set related information from the data packet header of the buffered data to be forwarded. The PDU set related information has been described in detail above and will not be repeated here.

[0248] For example, the execution condition of the first operation #2 may be that the first indication information indicates that the target base station does not have the PDU set processing capability. Alternatively, the execution condition may also be that the first indication information indicates that the target base station does not have the PDU set processing capability, and the first feedback message is used to indicate approval of the first switching request.

[0249] In this way, when the first indication information indicates that the target base station does not have the PDU set processing capability, the source base station can reduce the packet header size of the forwarded data while ensuring that the inter-station switching process between the source base station and the target base station remains unchanged by removing the relevant information of the PDU set in the data packet of the cached data to be forwarded, thereby reducing the consumption of forwarding link resources.

[0250] First operation #3: S604c, the source base station determines a new target base station.

[0251] That is, the source base station may abandon subsequent handover steps and try to find another base station that supports PDU set processing to re-initiate handover.

[0252] For example, the execution condition of the first operation #3 may be case one: the first indication information indicates that the target base station does not have the PDU set processing capability. Alternatively, the execution condition may also be case two: the first indication information indicates that the target base station does not have the PDU set processing capability, the first feedback message is used to indicate the approval of the first switching request, and the first feedback message is also used to indicate the acceptance of the QoS flow. Alternatively, the execution condition may also be case three: the first indication information indicates that the target base station does not have the PDU set processing capability, the first feedback message is used to indicate the approval of the first switching request, and the first feedback message is also used to indicate the non-acceptance of the QoS flow. Alternatively, the execution condition may also be case four: the first indication information indicates that the target base station does not have the PDU set processing capability, and the first feedback message is used to indicate the disapproval of the first switching request.

[0253] In this way, when the first indication information indicates that the target base station does not have the PDU set processing capability, by finding a more suitable new target base station, the capabilities of the two base stations for inter-station switching can be matched, ensuring the QoS guarantee based on PDU set, which is more suitable for the data transmission process based on PDU set.

[0254] First operation #4: S604d, the source base station sends a second handover request to the target base station, where the second handover request does not include the QoS parameter of the PDU set.

[0255] In other words, the source base station continues to send a second handover request to the target base station. The difference between the second handover request and the first handover request is that the second handover request does not include the QoS parameters of the PDU set. In other words, the source base station removes the QoS parameters of the PDU set from the QoS profile of the QoS flow requiring the PDU set, and then reverts the QoS flow to a normal QoS flow based on PDU granularity QoS requirements before sending the handover request to the target base station.

[0256] Optionally, when the target base station indicates to the source base station that it agrees to the second handover request, the relevant information of the PDU set in the buffered data to be forwarded is removed before forwarding.

[0257] For example, the execution condition of the first operation #4 may be that the first indication information indicates that the target base station does not have the PDU set processing capability. Alternatively, the execution condition may be that the first indication information indicates that the target base station does not have the PDU set processing capability, the first feedback message is used to indicate that the first handover request is approved, and the first feedback message is also used to indicate that the QoS flow is not accepted. Alternatively, the execution condition may be that the first indication information indicates that the target base station does not have the PDU set processing capability, and the first feedback message is used to indicate that the first handover request is not approved.

[0258] This allows for inter-station handover between the source and target base stations even when the first indication indicates that the target base station does not have the PDU set processing capability. This prevents service interruptions caused by the terminal's inability to switch in a timely manner. This also reduces the size of the forwarded data header, thereby minimizing the consumption of forwarding link resources.

[0259] It should be understood that the above S604a, S604b, or S604d is based on the example of communication between the source base station and the target via the Xn interface. The source base station can also perform the above S604a, S604b, or S604d via the NG interface through the core network and the target base station. This implementation is not shown in the drawings. For specific interaction methods, please refer to Figure 3 (b).

[0260] Figure 7 is a flow chart of another data transmission method provided by an embodiment of the present application. The interaction diagram of Figure 7 also uses the source base station and the target base station as the execution subjects of the interaction diagram during the switching process of the terminal device to illustrate the corresponding method, but the present application does not limit the execution subjects of the interaction diagram. For example, the source base station in Figure 7 can also be a chip, chip system or processor that supports the source base station to implement the corresponding method, or a logic module or software that can implement all or part of the functions of the source base station. The target base station in Figure 7 can also be a chip, chip system or processor that supports the target base station to implement the corresponding method, or a logic module or software that can implement all or part of the functions of the target base station.

[0261] It should be understood that since PDU set technology was introduced in 3GPP Release 18, some base stations in the actual network may not have been upgraded to Release 18. The target base station in Figure 7 is a non-upgraded base station, also known as an old base station. The source base station in Figure 7 is an upgraded base station, also known as a new base station.

[0262] S701: The source base station sends a fourth handover request to the target base station, where the fourth handover request includes QoS parameters of a PDU set.

[0263] It should be understood that the function of the fourth handover request and the QoS parameters for the PDU set included therein are similar to those of the first handover request, and are not described in detail here. Please refer to FIG. 6 .

[0264] S702: The target base station performs admission control in response to the fourth handover request.

[0265] It should be understood that since the target base station is an old base station that has not been upgraded, the target base station cannot identify the meaning of the parameters for the PDU set in the fourth handover request.

[0266] After admission control, the target base station determines a second feedback message.

[0267] It should be understood that since the target base station is an old base station, when determining the second feedback message, the target base station considers factors related to its own capabilities, such as the current load and available resources of the target base station.

[0268] The type of the second feedback message may be a handover request confirmation message or a handover preparation failure message.

[0269] S703, the target base station sends a second feedback message to the source base station, the second feedback message is used to indicate whether the target base station agrees to the fourth switching request, optionally, the second feedback message is also used to indicate whether to accept the QoS flow, wherein the QoS flow is a QoS flow with QoS requirements of PDU set.

[0270] It should be understood that the second feedback message in Figure 7 may include similar content to that in S603a-2 in Figure 6. For details, please refer to S603a-2 and will not be described in detail here.

[0271] That is, if the target base station is an old base station, the second feedback message does not include indication information of whether the target base station has the processing capability for the PDU set.

[0272] As a possible implementation, the second feedback message is used to indicate that the target base station agrees to the fourth handover request. Optionally, the second feedback message is further used to indicate that the QoS flow is accepted.

[0273] As a possible implementation, the second feedback message is used to indicate that the target base station agrees with the fourth handover request. Optionally, the second feedback message is further used to indicate that the target base station does not accept the QoS flow.

[0274] For example, the second feedback message may include a list of rejected QoS flows, which may include the QFIs corresponding to the rejected QoS flows. The rejected QoS flow list may also include a third reason field, which may include a specific reason or other reasons. The specific reason corresponding to the third reason field may be the capability status of the target base station, such as the current overload of the target base station or the lack of available resources.

[0275] As a possible implementation, the second feedback message is used to indicate that the target base station does not agree to the fourth handover request. The second feedback message may also include a fourth reason field, which may be a specific reason or other reasons. The specific reason corresponding to the fourth reason field may be the capability of the target base station, for example, the target base station is currently overloaded or has no available resources.

[0276] S704: The source base station determines whether the target base station is an old base station according to the second feedback message.

[0277] It should be understood that the source base station is unaware of whether the target base station has been upgraded. The source base station can determine that the target base station is an old base station because the second feedback message does not include feedback information indicating the processing capability for the PDU set, that is, it determines that the old base station does not have the processing capability for the PDU set.

[0278] S705: Execute the second operation.

[0279] The second operation can be understood as a handover operation related to inter-station handover. S705a to S705c are three possible second operations.

[0280] Second operation #1: S705a, the source base station sends fourth buffered data to the target base station, where the fourth buffered data does not include relevant information of the PDU set.

[0281] For example, the execution condition of the second operation #1 may be that the second feedback message is used to indicate that the fourth handover request is approved. Alternatively, the second feedback message may be used to indicate that the fourth handover request is approved and the QoS flow is admitted.

[0282] In this way, when the target base station is an old base station, the source base station can reduce the packet header size of the forwarded data while ensuring that the inter-station switching process between the source base station and the old base station that has not been upgraded remains unchanged, thereby reducing the consumption of forwarding link resources.

[0283] Second operation #2: S705b, the source base station determines a new target base station.

[0284] It should be understood that if the target base station is determined to be an old base station in S704 and the old base station does not have the processing capability for the PDU set, then the source base station may determine a new target base station.

[0285] As a possible implementation manner, the source base station may abandon subsequent handover steps and try to find another base station that supports PDU set processing to re-initiate handover.

[0286] For example, in this implementation, the execution condition of the second operation #2 can be Case 1: the second feedback message can be used to indicate the approval of the fourth handover request and the acceptance of the QoS flow. Case 2: the second feedback message can be used to indicate the approval of the fourth handover request, and the second feedback message is also used to indicate the non-acceptance of the QoS flow, wherein the list of non-accepted QoS flows included in the second feedback message can also include a third reason field, and the third reason field is used to indicate other reasons. That is, the second feedback message indicates that the target base station does not accept the QoS flow, but does not feedback the specific reason why the target base station does not accept the QoS flow. Case 3: the second feedback message can be used to indicate the disapproval of the fourth handover request, wherein the second feedback message can also include a fourth reason field, and the fourth reason field is used to indicate other reasons. That is, the second feedback message indicates that the target base station does not agree to the handover request, but does not feedback the specific reason why the target base station does not agree to the handover request.

[0287] As a possible implementation manner, the source base station may abandon the subsequent handover steps and determine a new target base station according to the reason for not agreeing to the fourth handover request or not accepting the QoS flow.

[0288] For example, in this implementation, the execution condition of the second operation #2 may be: the second feedback message is used to indicate that the fourth switching request is not agreed to and / or the QoS flow is not accepted, wherein the second feedback message may also include a third reason field or a fourth reason field, and the third reason field or the fourth reason field is used to indicate a reason related to the capabilities of the target base station, for example, the target base station is currently overloaded or has no available resources.

[0289] In this implementation, the determined new target base station may be a new target base station with a light load, or a new target base station with sufficient available resources.

[0290] Second operation #3: S705c, the source base station sends a fifth handover request to the target base station, where the fifth handover request does not include the QoS parameter of the PDU set.

[0291] It should be understood that the fifth handover request in S705c is similar to the second handover request in FIG6 , and will not be described in detail here.

[0292] For example, the execution condition of the second operation #3 may be that the second feedback message is used to indicate that the fourth switching request is not approved and / or the QoS flow is not admitted.

[0293] This allows for continued handover between the source and legacy base stations when the target base station is an older, unupgraded one, thus avoiding issues such as service interruption caused by delayed terminal handover. This also reduces the size of forwarded data headers, minimizing the consumption of forwarding link resources.

[0294] It should be understood that the above steps S701, S703, S705a, S705b, and S705c are based on the example of communication between the source base station and the target via the Xn interface. The source base station can also perform the above steps S701, S703, S705a, S705b, and S705c between the source base station and the target base station via the core network via the NG interface. This implementation is not shown in the accompanying drawings. For specific interaction methods, please refer to Figure 3 (b).

[0295] 8 and 9 respectively, from the perspective of the target base station, illustrate the possible process of determining the feedback message in response to the handover request during the admission control process, and from the perspective of the source base station, illustrate the possible process of determining the handover operation.

[0296] Figure 8 is a schematic diagram of a target base station behavior flow provided by an embodiment of the present application. It should be understood that Figure 8 is a comprehensive description of whether the target base station is a new base station or an old base station.

[0297] S801: Determine whether the target base station is a new base station.

[0298] If the target base station is an old base station, S802 , the target base station determines whether the second feedback message is used to indicate whether to approve the fourth handover request and / or whether to accept the QoS flow.

[0299] The second feedback message does not include the first indication information, that is, it does not include feedback information on whether the old base station has the processing capability for the PDU set.

[0300] If the target base station is a new base station, S803 determines whether the target base station accepts the QoS flow.

[0301] If the target base station accepts the QoS flow, S804 determines whether the target base station has the processing capability of the PDU set.

[0302] If the target base station has the capability to process the PDU set, in S805 , the target base station determines first indication information to indicate support for processing the PDU set.

[0303] If the target base station does not have the capability to process the PDU set, in S806 , the target base station determines first indication information to indicate that the processing of the PDU set is not supported.

[0304] At this time, the first feedback message may be used to indicate approval of the first switching request and acceptance of the QoS flow.

[0305] It should be understood that there is no restriction on the order of determination of S803 and S804, and FIG. 8 is only an exemplary description.

[0306] If the target base station does not accept the QoS flow, S807 determines whether the target base station rejects the QoS flow due to a lack of processing capability for the PDU set.

[0307] Optionally, the target base station can also determine whether to agree to the first switching request. The factors considered in the first switching request may be the processing capability of the target base station for the PDU set, or other capabilities of the target base station, such as the load condition of the target base station and the available resources of the target base station.

[0308] If the reason for the target base station to reject the QoS flow is that the target base station does not have the processing capability for the PDU set, S808 , the first indication information determined by the target base station indicates that the processing of the PDU set is not supported.

[0309] At this time, the first feedback message may be used to indicate that the first switching request is approved and that the QoS flow is not admitted. Alternatively, the first feedback message may also be used to indicate that the first switching request is not approved.

[0310] If the target base station rejects the QoS flow due to a reason other than the target base station's inability to process the PDU set, in step S809, the target base station determines a first feedback message to indicate another reason. Alternatively, in addition to determining the first feedback message, the target base station may also determine first indication information to indicate whether the PDU set cannot be processed.

[0311] At this time, the first feedback message may also be used to indicate that the target base station agrees to the first handover request and does not accept the QoS flow. Alternatively, the first feedback message may also be used to indicate that the target base station does not agree to the first handover request.

[0312] The first feedback message determined by the target base station in S803 to S809 may include the first indication information or may not include the first indication information. It should be understood that the specific situation can be referred to FIG6 .

[0313] Figure 9 is a schematic diagram of a behavior flow of a source base station provided in an embodiment of the present application. It should be understood that Figure 9 is a comprehensive description of the switching operation after the source base station receives different feedback messages.

[0314] S901: The source base station determines whether first indication information is received.

[0315] The first indication information is used to indicate whether the target base station has the processing capability for the PDU set.

[0316] If the source base station determines that the first indication information is received, S902 : Determine whether the target base station supports PDU set processing according to the first indication information.

[0317] If the first indication information is used to indicate that the target base station supports PDU set processing, S903 , execute the first operation #1.

[0318] If the first indication information is used to indicate that the target base station does not support PDU set processing, S904 : Determine whether the target base station agrees to the first handover request according to the first feedback message.

[0319] If the first feedback message is used to indicate approval of the first switching request, S905 , perform the first operation # 3 or the first operation # 2.

[0320] If the first feedback message is used to indicate that the first switching request is not approved, S906 , perform the first operation # 3 or the first operation # 4.

[0321] It should be understood that the aforementioned first operations #1, #2, #3, and #4 can be referred to in Figure 6 and will not be described in detail here. Furthermore, the conditions for triggering the execution of these operations can be specifically referred to in the description of Figure 6. Furthermore, there is no specific order in which S902, S903, and S904 are determined; Figure 9 is merely an example.

[0322] If the source base station determines that the first indication information is not received, the source base station determines that the target base station is an old base station. In step S902 , the source base station determines whether the target base station agrees to the fourth handover request based on the second feedback message.

[0323] If the second feedback message is used to indicate approval of the fourth switching request, S908 : perform the second operation #1 or the second operation #2.

[0324] If the second feedback message is used to indicate that the fourth switching request is not approved, S909 , perform the second operation #3 or the second operation #2.

[0325] It should be understood that the above second operation #1, second operation #2 and second operation #3 can refer to FIG7 and are not described in detail here. In addition, the execution conditions for triggering these operations can be specifically referred to the description in FIG7.

[0326] If the first operation #4 or the second operation #3 in the switching operation of Figure 6, Figure 7 or Figure 9 is performed, the QoS parameters for the PDU set have been removed from the switching request sent by the source base station to the target base station, and the target base station does not know that the service data of the terminal device requires QoS protection based on the PDU set. Therefore, the QoS configuration file saved by the current target base station does not include the QoS parameters for the PDU set. When the terminal device needs to switch from the current target base station to the next target base station during the switching process, the switching request at this time will not include the QoS parameters for the PDU set. If the next target base station has the processing capability for the PDU set, at this time, the next target base station will not feedback to the core network that it has the processing capability for the PDU set. Therefore, the core network will not add relevant information about the PDU set to the data packet, resulting in the terminal device no longer being able to return to the QoS guarantee based on the PDU set.

[0327] Therefore, the embodiments of the present application propose further improvement solutions to the above problems.

[0328] FIG10 is a flow chart of another data transmission method provided in an embodiment of the present application.

[0329] S1001: The core network sends a QoS configuration file to the base station where the terminal device is located. The QoS configuration file includes QoS parameters for PDU set.

[0330] As a possible implementation method, the core network periodically sends the QoS configuration file to the base station where the terminal device is located until a new base station accepts the new QoS configuration file.

[0331] It should be understood that the base station where the terminal device is located may also resend the QoS configuration file to the target base station each time the terminal device switches to the target base station.

[0332] In this way, since the core network side always saves the complete QoS configuration file, which includes the QoS parameters for PDU set, through this refresh method, even if the QoS configuration file on the base station side loses the PDU set QoS parameters, it can be obtained again from the core network, thereby re-enabling the relevant processing for PDU set.

[0333] Optionally, before S1001, S1002, after the terminal device switching process occurs, the source base station sends a first notification message to the core network, and the first notification message is used to indicate that the QoS parameters for the PDU set in the QoS configuration file in the source base station have been deleted.

[0334] The execution condition of S1002 may be that the source base station executes the first operation #4 or the second operation #3.

[0335] In this way, not only can the service data based on PDU set QoS protection in the terminal device be guaranteed not to be downgraded to PDU-based QoS protection due to cell switching, but the signaling interaction between the core network and the base station can also be reduced.

[0336] This method allows the source base station to learn about the target base station's processing capabilities for PDU sets during an inter-base handover. Before an inter-base handover occurs, the source base station can also learn about the processing capabilities of surrounding base stations for PDU sets.

[0337] Figure 11 is a flow chart of another data transmission method provided by an embodiment of the present application. The interaction diagram shown in Figure 11 takes the source base station, candidate base station B and core network as the execution subjects of the interaction diagram as an example to illustrate the corresponding method, but the present application does not limit the execution subjects of the interaction diagram. For example, the source base station in Figure 11 can also be a chip, chip system or processor that supports the source base station to implement the corresponding method, or a logic module or software that can implement all or part of the functions of the source base station. The candidate base station B in Figure 11 can also be a chip, chip system or processor that supports the candidate base station B to implement the corresponding method, or a logic module or software that can implement all or part of the functions of the candidate base station B. The core network in Figure 11 can be a chip, chip system or processor that supports the core network to implement the corresponding method, or a logic module or software that can implement all or part of the functions of the core network.

[0338] S1101: A source base station sends a first capability query message to a core network. The first capability query message is used to query a processing capability of at least one candidate base station for a PDU set.

[0339] For example, the at least one candidate base station may include candidate base station A and candidate base station B as shown in FIG11 .

[0340] Specifically, the first capability query message includes an identification list of at least one candidate base station.

[0341] S1102: The core network sends second indication information to the source base station, where the second indication information is used to indicate a processing capability of at least one candidate base station for a PDU set.

[0342] Optionally, the core network determines the second indication information.

[0343] It should be understood that the core network is likely to have information about each base station's processing capabilities for PDU sets. This is because whenever a terminal device wants to perform a QoS-guaranteed service based on a PDU set (such as an XR service), the core network will request feedback from the base station where the terminal device is located regarding its processing capabilities when establishing a PDU session or QoS flow for that service. Since this is base station capability information, once a base station has provided feedback to the core network, the core network will have a complete understanding of the base station's situation.

[0344] As a possible implementation manner, if the core network knows the processing capability of at least one candidate base station for the PDU set, the second indication information is used to indicate whether the at least one candidate base station supports processing the PDU set.

[0345] As a possible implementation method, if the core network has not obtained the processing capability of a certain base station in at least one candidate base station for the PDU set, the second indication information is used to indicate that the processing capability of a certain base station for the PDU set is unknown or non-existent, and whether other base stations in at least one candidate base station support processing the PDU set.

[0346] If the core network has not obtained the processing capability of at least one of the candidate base stations for the PDU set, for example, the core network is unknown to the core network the processing capability of the candidate base station B for the PDU set.

[0347] Optionally, in S1103 , the core network sends a second capability query message to the candidate base station B, where the second capability query message is used to query the processing capability of the candidate base station B for the PDU set.

[0348] Optionally, in S1104 , the candidate base station B sends a first capability report to the core network, where the first capability report is used to indicate whether the candidate base station B supports processing PDU set.

[0349] It should be understood that the first capability query message sent by the source base station to the core network may also be further forwarded within the core network. For example, the source base station sends the message to the AMF, and the AMF forwards the message to the SMF. Similarly, the first capability report of candidate base station B may also go through the above forwarding process. Correspondingly, the second capability query message sent by the core network may also be sent by the SMF to the AMF, and then forwarded by the AMF to candidate base station B.

[0350] Optionally, in S1107 , within the second time period, candidate base station B no longer reports the first capability.

[0351] Specifically, the second duration can be implemented using a first timer. For example, after executing S1104, candidate base station B starts the first timer, and during the second duration, candidate base station B no longer sends the first capability report to the core network. The second duration can be pre-defined by the protocol, pre-configured by the core network to candidate base station B, or determined by candidate base station B itself.

[0352] The source base station may perform the third operation according to the second indication information.

[0353] Optionally, S1105, during the terminal device switching process, determine the target base station according to the second indication information.

[0354] Specifically, the source base station determines the candidate base station with the processing capability of the PDU set among the at least one candidate base station as the target base station in the terminal device switching process according to the processing capability of the at least one candidate base station for the PDU set indicated in the second indication information.

[0355] For example, when selecting a target base station for handover, the source base station can take the acquired base station capability information into consideration. When there are two candidate base stations and the terminal device's reference signal quality is comparable (e.g., the amplitude difference is no more than 1dB), the source base station preferentially selects the base station that supports PDU set processing as the target base station for inter-base station handover.

[0356] In the above technical solution, by understanding the processing capability of at least one candidate base station for PDU set, the candidate base station with PDU set processing capability is used as the target base station during the inter-station switching process, thereby ensuring the QoS requirements of the terminal device based on PDU set.

[0357] Optionally, S1106, during the switching process of the terminal device, one of the at least one candidate base stations is used as the target base station, the target base station does not support processing PDU set, and the switching request sent to the target base station includes or does not include QoS parameters for the PDU set. When the target base station agrees to the switching request, the source base station sends third cached data to the target base station. The third cached data belongs to a QoS flow with QoS requirements of the PDU set, and the third cached data does not include relevant information of the PDU set.

[0358] In the above technical solution, even if there is no candidate base station around the source base station that has the processing capability for PDU set, a suitable inter-base station handover strategy can be determined in advance, thereby improving data forwarding efficiency and avoiding resource waste.

[0359] In the solution shown in Figure 11, the source base station sends a first capability query message to the core network. Optionally, the source base station can also directly send capability query messages to surrounding base stations to inquire whether they have the processing capability for the PDU set. After receiving the capability query message, the surrounding base stations provide feedback on their own capabilities to the source base station. Alternatively, the source base station directly obtains the processing capability of surrounding base stations for the PDU set from a network administrator (such as an operator's network management system).

[0360] For XR services, the higher the data transmission rate, the better. The transmission rate is the rate at which the application server sends data to the transmission network, that is, the rate at which the application server generates data, not the actual transmission rate of the application data in the network.

[0361] Taking video as an example, with a fixed frame rate, a higher transmission rate (or bit rate) means higher definition for each frame. However, due to limited network bandwidth, a higher transmission rate does not necessarily mean a higher transmission rate. When the transmission rate exceeds the available network bandwidth, packet loss and other phenomena may occur, which in turn degrades the user experience.

[0362] For example, consider a video service with a transmission rate of 50 Mbps for 1080p and 200 Mbps for 4K, while the network bandwidth is limited to 100 Mbps. When the resolution is 1080p, the available network bandwidth exceeds the video transmission rate, allowing the network to support the transmission of all video data and users to watch the video normally. However, if the resolution is adjusted to 4K, the available network bandwidth will be less than the video transmission rate, inevitably preventing some video data from being transmitted in a timely manner. This may result in incomplete or even undecoded video frames, leading to black screens, black edges, and lags during video playback, severely degrading the user experience.

[0363] Therefore, the sending rate of XR services should be adjusted according to the network status. For example, when the network is congested and the available bandwidth becomes smaller, the application should reduce the sending rate of XR services to avoid problems such as service lag, which affects the user experience.

[0364] To achieve the above objectives in 5G systems, 3GPP has designed a 5G low-latency, low-loss, and scalable throughput (L4S) mechanism to enable applications to perceive the status of the 5G transmission network. For 5G networks, the bottleneck of speed lies in the air interface transmission part, so the congestion state of the 5G network can also be understood as the congestion state of the air interface. Figure 12 is a schematic diagram of the operation mode of the L4S mechanism provided in an embodiment of the present application.

[0365] As shown in Figure 12, the L4S mechanism of the 5G system operates in the following ways: in the first way, the core network decides to add an explicit congestion notification (ECN) flag, or a Congestion Experienced (CE) flag, to the IP header of the data packet through the 5G base station. The 5G base station receives the data packet from the application server and adds the ECN flag to some of the data packets based on the network congestion status. In the second way, the core network decides to add the ECN flag to the IP header of the data packet. In this case, the core network needs to obtain the congestion information of the air interface from the 5G base station and determine the data packet to add the ECN flag based on the congestion information. When the terminal device receives a data packet carrying the ECN flag, the application of the terminal device can judge the network congestion status based on the proportion of data packets carrying the ECN flag in the received data packets, and trigger the application server to adjust the data packet sending rate. Figure 12 shows the downlink data transmission method. The uplink data transmission method is similar and is not shown in the figure.

[0366] Currently, 3GPP only requires base stations to report to the core network whether they have the ability to process a specific PDU set. Different base stations may have different capabilities for the L4S mechanism, and the core network cannot determine whether or how a base station should implement the L4S mechanism based on its PDU set processing capabilities. Therefore, how to inform the core network of a base station's L4S mechanism so that it can make appropriate data transmission decisions is an urgent issue.

[0367] Figure 13 is a flow chart of another data transmission method provided by an embodiment of the present application. The interaction diagram shown in Figure 13 takes the first base station, the second base station and the core network as the execution subjects of the interaction diagram as an example to illustrate the corresponding method, but the present application does not limit the execution subjects of the interaction diagram. For example, the first base station in Figure 13 can also be a chip, a chip system or a processor that supports the first base station to implement the corresponding method, or it can be a logic module or software that can implement all or part of the functions of the first base station. The second base station in Figure 13 can also be a chip, a chip system or a processor that supports the second base station to implement the corresponding method, or it can be a logic module or software that can implement all or part of the functions of the second base station. The core network in Figure 13 can be a chip, a chip system or a processor that supports the core network to implement the corresponding method, or it can be a logic module or software that can implement all or part of the functions of the core network.

[0368] S1301. The first base station determines third indication information, where the third indication information is used to indicate capability information of the first base station for an L4S mechanism.

[0369] As a possible implementation manner, the third indication information is used to indicate whether the first base station has both ECN marking capability and congestion information reporting capability.

[0370] When the third indication information is used to indicate that the first base station has capability information for the L4S mechanism, the first base station has ECN marking capability and congestion information reporting capability. When the third indication information is used to indicate that the first base station does not have capability information for the L4S mechanism, the first base station does not have ECN marking capability and congestion information reporting capability.

[0371] For example, one bit is used to represent the third indication information. When the value of the bit is the fifth value, for example, the bit value is "1," the third indication information is used to indicate that the first base station has the ECN marking capability and the congestion information reporting capability. When the value of the bit is the sixth value, for example, the bit value is "0," the third indication information is used to indicate that the first base station does not have the ECN marking capability and the congestion information reporting capability.

[0372] For another example, the third indication information is represented by an enumeration type. When the enumeration value indicates support, the third indication information is used to indicate that the first base station has the ECN marking capability and the congestion information reporting capability. When the enumeration value indicates not support, the third indication information is used to indicate that the first base station does not have the ECN marking capability and the congestion information reporting capability.

[0373] As a possible implementation manner, the third indication information is used to indicate whether the first base station has ECN marking capability and congestion information reporting capability respectively.

[0374] In other words, the first base station may indicate the ECN marking capability and the congestion information reporting capability respectively through the third indication information.

[0375] For example, two bits are used to represent the third indication information. The first bit is used to indicate whether the first base station supports ECN marking. A value of "1" indicates support, while a value of "0" indicates non-support. The second bit is used to indicate whether the first base station supports congestion information reporting. A value of "1" indicates support, while a value of "0" indicates non-support. It should be understood that the specific bit values ​​corresponding to the third indication information are for illustrative purposes only and are not limited in this embodiment of the present application.

[0376] It should be understood that in this implementation, the third indication information may be in one message, for example, one message includes two bits of the third indication information. Alternatively, the third indication information may be in two messages, for example, two messages each include two bits of the third indication information, that is, one message includes one bit of the third indication information, and the other message includes the other bit of the third indication information.

[0377] As a possible implementation manner, the third indication information is used to indicate whether the first base station has an ECN marking capability or a congestion information reporting capability.

[0378] For example, one bit is used to represent the third indication information. When the value of this bit is "1," the third indication information indicates that the first base station has ECN marking capability. When the value of this bit is "0," the third indication information indicates that the first base station does not have ECN marking capability. It should be understood that the specific bit values ​​corresponding to the third indication information are merely illustrative and are not limiting in this embodiment of the present application.

[0379] For another example, one bit is used to represent the third indication information. When the value of this bit is "1," the third indication information indicates that the first base station has the capability to report congestion information. When the value of this bit is "0," the third indication information indicates that the first base station does not have the capability to report congestion information. It should be understood that the specific bit values ​​corresponding to the third indication information are merely illustrative and are not limited in this embodiment of the present application.

[0380] S1302. When a trigger condition is met, the first base station sends third indication information to the core network.

[0381] As a possible implementation method, after the trigger condition is met, the first base station sends a third indication information to the core network when the first base station has both the ECN marking capability and the congestion information reporting capability in the L4S mechanism, or has the ECN marking capability, or has the congestion information reporting capability.

[0382] At this time, when the first base station does not send the third indication information to the core network, it means that the first base station does not have the ECN marking capability and congestion information reporting capability in the L4S mechanism, or does not have the ECN marking capability, or does not have the congestion information reporting capability.

[0383] As a possible implementation method, after the trigger condition is met, the first base station sends a third indication information to the core network when the first base station does not have the ECN marking capability and congestion information reporting capability in the L4S mechanism, or does not have the ECN marking capability, or does not have the congestion information reporting capability.

[0384] At this time, when the first base station does not send the third indication information to the core network, it means that the first base station has both the ECN marking capability and the congestion information reporting capability in the L4S mechanism, or has the ECN marking capability, or has the congestion information reporting capability.

[0385] In the above technical solution, the first base station can promptly notify the core network of its L4S support, enabling the core network to understand the first base station's capabilities and select the appropriate method when L4S is required. This helps to promptly adjust the service transmission rate and improve the user experience. For example, if the first base station only supports ECN marking but not congestion reporting, the core network can instruct the first base station to perform ECN marking. If the first base station only supports congestion reporting but not ECN marking, the core network can instruct the first base station to perform congestion reporting and take over the ECN marking work, thus ensuring the normal operation of L4S.

[0386] It should be understood that before S1301 , there are several possible implementations of the trigger condition.

[0387] S1302a: The core network sends a first capability reporting request to the first base station, where the first capability reporting request is used to request capability information of the first base station for the L4S mechanism.

[0388] As a possible implementation method, the first capability reporting request is used to request the first base station for the ECN marking capability and congestion information reporting capability in the L4S mechanism; or, the first capability reporting request is used to request the ECN marking capability of the first base station, or, the first capability reporting request is used to request the congestion information reporting capability.

[0389] That is, the ECN marking capability and the congestion information reporting capability in the L4S mechanism can be included in one capability reporting request or in two capability reporting requests.

[0390] Specifically, satisfying the trigger condition may be sending third indication information in response to the first capability reporting request.

[0391] It should be understood that the embodiment of the present application does not limit whether the first base station sends the third indication information when it has capability information for the L4S mechanism or sends the third indication information when it does not have capability information for the L4S mechanism after the trigger condition is met.

[0392] S1302b: The core network sends a first start message to the first base station, where the first start message is used to instruct the first base station to mark ECN and / or start a congestion information reporting operation.

[0393] As a possible implementation, the core network sends a first start message for any QoS flow or DRB. It should be understood that the first start message may be for a specific QoS flow or DRB.

[0394] Specifically, the trigger condition may be that the first base station has the ECN marking capability and / or the congestion information reporting capability, and sends the third indication information. Alternatively, the trigger condition may be that the first base station does not have the ECN marking capability and / or the congestion information reporting capability, and sends the third indication information.

[0395] S1302c: The first base station determines that the first data includes a QoS flow for the L4S mechanism.

[0396] As a possible implementation method, when establishing a QoS flow, the core network indicates to the first base station through the first data that the QoS flow supports the L4S function (for example, a specific QFI is used), and the first base station determines that it may be necessary to enable the function for the L4S mechanism subsequently.

[0397] Specifically, satisfying the trigger condition may be sending the third indication information after receiving the first data.

[0398] It should be understood that the embodiment of the present application does not limit whether the first base station sends the third indication information when it has capability information for the L4S mechanism or sends the third indication information when it does not have capability information for the L4S mechanism after the trigger condition is met.

[0399] S1302d: The first base station receives a second start message from the second base station, where the second start message is used to instruct the first base station to mark ECN and / or start a congestion information reporting operation.

[0400] As a possible implementation method, the second startup information instructs the first base station to mark the uplink data flow or downlink data flow of the first QoS flow or the first DRB in the terminal device with ECN and / or start a congestion information reporting operation.

[0401] It should be understood that the first QoS flow is any QoS flow in the terminal device, and the first DRB is any DRB in the terminal device.

[0402] As a possible implementation method, the second startup information is used to indicate that the second base station has or is marking ECN and / or performing congestion information reporting operations for the uplink data flow or downlink data flow of the second QoS flow or the second DRB in the terminal device.

[0403] It should be understood that the second QoS flow is any QoS flow in the terminal device, and the second DRB is any DRB in the terminal device.

[0404] As a possible implementation manner, the second startup information is carried in a third switching request, and the third switching request is used to request the terminal device to switch from the second base station to the first base station.

[0405] As a possible implementation, the second startup information is carried in a first response message. The first response message is a response to a terminal device context query request message sent by the first base station to the second base station. The first response message is used to indicate the context of the terminal device to the first base station. It should be understood that before receiving the first response message, the first base station sends a terminal device context query request message to the second base station. The context query request message is used to query the context of the terminal device.

[0406] Specifically, satisfying the trigger condition may be sending third indication information in response to the second start message.

[0407] It should be understood that the embodiment of the present application does not limit whether the first base station sends the third indication information when it has capability information for the L4S mechanism or sends the third indication information when it does not have capability information for the L4S mechanism after the trigger condition is met.

[0408] Optionally, the first base station sends a third feedback message to the second base station.

[0409] As a possible implementation, when the type of the third feedback message is a handover request confirmation message and the first base station refuses to accept the QoS flow, the reason for refusing to accept the QoS flow is added to the third feedback message. For example, the first base station does not have the ECN marking capability and congestion information reporting capability in the L4S mechanism, or the first base station does not have the ECN marking capability, or the first base station does not have the congestion information reporting capability.

[0410] As a possible implementation, when the type of the third feedback message is a handover preparation failure message and the first base station does not agree to the third handover request, a reason for rejecting the third handover request is added to the third feedback message. For example, the first base station does not have the ECN marking capability and congestion information reporting capability in the L4S mechanism, or the first base station does not have the ECN marking capability, or the first base station does not have the congestion information reporting capability.

[0411] It should be understood that the embodiment of the present application does not limit the number of times the third indication information is reported when the trigger condition is met. Once the first base station meets the above trigger condition, the third indication information can be sent to the core network.

[0412] Alternatively, the first base station sends the third indication information to the core network only once.

[0413] In this way, once the first base station reports the third indication information once, it will never report the same third indication information again. This is because the capability of the first base station will not change easily. After receiving it once, the core network can understand the capability of the first base station, which can reduce the frequency of information interaction and thus reduce resource consumption.

[0414] Optionally, in S1303, the first base station no longer sends the third indication information within the first time period, and the starting moment of the first time period is when the third indication information is sent each time.

[0415] For example, the first base station starts the second timer each time after sending the third indication information. During the timer running, the first base station no longer sends the third indication information to the core network.

[0416] The first duration may be pre-defined by a protocol, or configured to the first base station by the core network, or determined by the first base station itself.

[0417] In the above technical solution, by limiting the sending frequency of the third indication information through a preset time length, the two extreme sending methods of frequently sending the third indication information and sending the third indication information once can be avoided, thereby reducing the frequency of capability reporting and ensuring the timeliness and accuracy of capability reporting.

[0418] Optionally, in S1304, the core network determines the behavior of the first base station with respect to the L4S mechanism based on the third indication information.

[0419] Specifically, when the core network decides to enable the L4S function for the terminal device, the core network may instruct the first base station to perform ECN marking for a specific QoS flow or a specific DRB of the terminal device through the fourth indication information. Furthermore, the core network may instruct the first base station to perform ECN marking for the uplink data flow or downlink data flow of the specific QoS flow or DRB.

[0420] Alternatively, if the core network sends fifth indication information to the first base station instructing the first base station to report congestion information for the uplink data flow or downlink data flow of a specific QoS flow or a specific DRB, the first base station sends sixth indication information to the core network, and the sixth indication information indicates the congestion status of the uplink data flow or downlink data flow of the specific QoS flow or specific DRB of the terminal device, for example, using a percentage to express the degree of congestion. The core network performs ECN marking for the specific QoS flow or specific DRB of the terminal device based on the congestion information.

[0421] Alternatively, if the core network sends the seventh indication information to the first base station instructing the first base station to perform ECN marking on the uplink data flow or downlink data flow of the specific QoS flow or specific DRB of the terminal device and report congestion information, the first base station sends the eighth indication information to the core network, and the eighth indication information is used to indicate the congestion status of the uplink data flow or downlink data flow of the specific QoS flow or specific DRB of the terminal device, and the first base station performs ECN marking on the uplink data flow or downlink data flow of the specific QoS flow or specific DRB of the terminal device.

[0422] Optionally, when the first base station is in a CU-DU separation scenario, after the CU of the first base station receives the fourth indication information, the fifth indication information, or the seventh indication information, it further instructs the DU to transmit the fourth indication information, the fifth indication information, or the seventh indication information. Messages between the CU and the DU can be transmitted through the F1 interface.

[0423] Specifically, when the first base station is in a CU-DU separation scenario, the first base station receives the fourth indication information or the seventh indication information, instructing the first base station to perform ECN marking on the uplink data flow or downlink data flow of a specific QoS flow or DRB, and the DU can send congestion information to the CU. Based on the congestion information, the CU performs an ECN marking operation at the packet data convergence protocol (PDCP) layer. When the first base station is in a CU-DU separation scenario, the first base station receives the fifth indication information or the seventh indication information, instructing the first base station to report congestion information. The CU of the first base station sends the fifth indication information or the seventh indication information to the DU, and the DU reports the congestion information to the CU. Messages between the CU and the DU can be transmitted through the F1 interface. For example, the DU can carry congestion information in a data packet sent to the CU.

[0424] It should be understood that the DU has a better understanding of the air interface congestion status, so the CU needs the DU to provide auxiliary information to determine which data packets to add the ECN mark to.

[0425] Optionally, when the first base station is a primary base station in a dual connectivity (DC) scenario, after receiving the fourth indication information, the fifth indication information, or the seventh indication information, the first base station further indicates the fourth indication information, the fifth indication information, or the seventh indication information to the secondary base station. Messages between the first base station and the secondary base station can be transmitted over an Xn interface. For example, the secondary base station can carry congestion information in a data packet sent to the first base station.

[0426] Specifically, when the first base station is the main base station in the DC scenario, when the first base station receives the fourth indication information or the seventh indication information, instructing the first base station to perform ECN marking for the uplink data flow or downlink data flow of a specific QoS flow or DRB, the secondary base station can send congestion information to the first base station. The first base station performs an ECN marking operation based on the congestion information. When the first base station is the main base station in the DC scenario, the first base station receives the fifth indication information or the seventh indication information, instructing the first base station to report congestion information. The first base station sends the fifth indication information or the seventh indication information to the secondary base station, and the secondary base station reports the congestion information to the first base station. Messages between the first base station and the secondary base station can be transmitted through the Xn interface. For example, the secondary base station can carry congestion information in a data packet sent to the first base station.

[0427] It should be understood that the secondary base station has a better understanding of the congestion situation, so the first base station needs the secondary base station to provide congestion information to determine which data packets to add ECN marks to.

[0428] Optionally, the message received by the core network from the first base station, or the message sent by the core network to the first base station, can be transmitted through one or more of AMF, SMF and UPF.

[0429] For example, the third indication information received by the core network from the first base station can first be received by the AMF of the core network, and then sent to the SMF of the core network. The message between the AMF and the base station can be transmitted through the NG interface.

[0430] For example, the first capability reporting request sent by the core network to the first base station can be sent to the AMF of the core network through the SMF of the core network, and then sent to the first base station through the AMF of the core network. The message between the AMF and the base station can be transmitted through the NG interface.

[0431] For example, the fourth indication information, the fifth indication information, or the seventh indication information sent by the core network to the first base station can be sent to the AMF of the core network through the SMF of the core network, and then sent to the first base station through the AMF of the core network. Messages between the AMF and the base station can be transmitted through the NG interface.

[0432] For another example, the sixth indication information or the eighth indication information sent by the first base station to the core network can be sent to the UPF of the core network through the NG interface. Specifically, the above message can be carried in the header of the data packet sent by the first base station to the UPF.

[0433] Optionally, when the first base station is in a CU-DU separation scenario, before the first base station sends the sixth indication information or the eighth indication information to the core network, the DU may send congestion information to the CU. This is because the DU has a better understanding of the air interface congestion status. The DU may send congestion information to the CU via the F1 interface. For example, the DU may carry the congestion message in the data packet sent to the CU.

[0434] Optionally, when the first base station is a primary base station in a DC scenario, before the first base station sends the sixth indication information or the eighth indication information to the core network, the secondary base station may send congestion information to the first base station. Messages between the first base station and the secondary base station may be transmitted via an Xn interface. For example, the secondary base station may carry congestion information in a data packet sent to the first base station.

[0435] The data transmission method provided by the embodiment of the present application is described in detail above with reference to Figures 5 to 13. It is understood that in order to implement the above functions, it includes hardware structures and / or software modules corresponding to executing each function.

[0436] Those skilled in the art should be aware that, in combination with the units and algorithm steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is performed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for specific applications, but such implementation should not be considered to be beyond the scope of this application.

[0437] The data transmission device provided in the embodiment of the present application is described in detail below with reference to Figures 14 to 16. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment. Therefore, for matters not described in detail, reference can be made to the method embodiment above. For the sake of brevity, some contents are not repeated here.

[0438] Figure 14 is a schematic diagram of a data transmission device 1400 provided in an embodiment of the present application. The device 1400 may include a processing unit 1420, which is used to perform data processing. The device 1400 may also include a transceiver unit 1410, which may implement corresponding communication functions. The transceiver unit 1410 may also be referred to as a communication interface or a communication unit or an interface unit. It should be understood that for the operations such as sending and receiving involved in this application, if there is no special explanation, or if it does not conflict with its actual function or internal logic in the relevant description, it can be more generally understood as operations such as output and input, rather than sending and receiving operations directly performed by the radio frequency circuit and antenna.

[0439] Optionally, the device 1400 may further include a storage unit, which may be used to store instructions and / or data. The processing unit 1420 may read the instructions and / or data in the storage unit so that the device implements the aforementioned method embodiment.

[0440] The device 1400 can be used to execute the actions performed by the source base station in the above method embodiment. In this case, the device 1400 can be a communication device or a component that can be configured in a communication device. The transceiver unit 1410 is used to execute the transceiver-related operations on the communication device side in the above method embodiment, and the processing unit 1420 is used to execute the processing-related operations of the source base station in the above method embodiment.

[0441] As a design, the apparatus 1400 is used to execute the actions performed by the source base station during the terminal device handover process in the method embodiments shown in FIG. 5 or FIG. 6 . The execution subject can be a chip, chip system, or processor that supports the source base station in implementing the corresponding method, or a logic module or software that can implement all or part of the functions of the source base station.

[0442] Specifically, the transceiver unit 1410 is configured to send a first handover request, where the first handover request includes a quality of service (QoS) parameter of a protocol data unit (PDU) set of the terminal device, and receive first indication information, where the first indication information is used to indicate a processing capability of a target base station for the PDU set during a handover of the terminal device.

[0443] The processing unit 1420 is configured to perform a switching operation according to the first indication information.

[0444] For details not described in detail, please refer to the above method embodiment.

[0445] As a design, the data transmission device 1400 is used to perform the actions performed by the source base station in the method embodiment shown in Figure 7 above. The execution subject can be a chip, chip system, or processor that supports the source base station in implementing the corresponding method, or it can be a logic module or software that can implement all or part of the functions of the source base station.

[0446] Specifically, the transceiver unit 1410 is configured to send a first capability query message, the first capability query message being used to query the processing capability of at least one candidate base station for a set of protocol data units (PDUs), where the at least one candidate base station will be used in a terminal device handover process. The transceiver unit 1410 is configured to receive second indication information, the second indication information being used to indicate the processing capability of the at least one candidate base station for the set of PDUs. The processing unit 1420 is configured to perform a handover operation based on the second indication information.

[0447] For details not described in detail, please refer to the above method embodiment.

[0448] As a design, the data transmission device 1400 is used to perform the actions performed by the source base station in the method embodiment shown in Figure 11 above. The execution subject can be a chip, chip system or processor that supports the source base station to implement the corresponding method, or it can be a logic module or software that can implement all or part of the functions of the source base station.

[0449] Specifically, transceiver unit 1410 is configured to send a fourth handover request, where the first handover request includes quality of service (QoS) parameters for the PDU set. Transceiver unit 1410 is configured to receive a second feedback message. Processing unit 1420 is configured to determine, based on the first feedback message, that the target base station during the handover of the terminal device is an old base station, and that the old base station does not have the processing capability for the protocol data unit (PDU) set. Processing unit 1420 is configured to perform a second operation.

[0450] For details not described in detail, please refer to the above method embodiment.

[0451] As a design, the data transmission device 1400 is used to execute the actions performed by the first base station in the method embodiment shown in Figure 13 above. The execution entity can be a chip, chip system, or processor that supports the first base station in implementing the corresponding method, or a logic module or software that can implement all or part of the functions of the first base station.

[0452] Specifically, the processing unit 1420 is used to determine the third indication information, which is used to indicate the capability information of the first base station for the low latency, low loss and scalable throughput L4S mechanism. The transceiver unit 1410 is used to send the third indication information to the core network when the trigger condition is met.

[0453] For details not described in detail, please refer to the above method embodiment.

[0454] It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

[0455] The processing unit 1420 in the above embodiment may be implemented by at least one processor or processor-related circuits. The transceiver unit 1410 may be implemented by a transceiver or transceiver-related circuits. The storage unit may be implemented by at least one memory.

[0456] FIG15 is a schematic structural diagram of a data transmission device 1500 provided in an embodiment of the present application.

[0457] As shown in Figure 15, an embodiment of the present application further provides a data transmission device 1500. The device 1500 includes a processor 1510, which is coupled to a memory 1520. The memory 1520 is used to store computer programs or instructions and / or data. The processor 1510 is used to execute the computer programs or instructions and / or data stored in the memory 1520, so that the method in the above method embodiment is executed.

[0458] Optionally, the device 1500 includes one or more processors 1510.

[0459] Optionally, as shown in FIG15 , the device 1500 may further include a memory 1520 .

[0460] Optionally, the device 1500 may include one or more memories 1520 .

[0461] Optionally, the memory 1520 may be integrated with the processor 1510 or provided separately.

[0462] Optionally, as shown in Figure 15, the apparatus 1500 may further include a transceiver 1530, which is configured to receive and / or transmit signals. For example, the processor 1510 is configured to control the transceiver 1530 to receive and / or transmit signals.

[0463] As a solution, the device 1500 is used to implement the operations performed by the source base station, the target base station, the first base station, the second base station or the core network in the above method embodiment.

[0464] For example, the processor 1510 is used to implement the processing-related operations performed by the source base station, target base station, first base station, second base station or core network in the above method embodiments, and the transceiver 1530 is used to implement the transceiver-related operations performed by the source base station, target base station, first base station, second base station or core network in the above method embodiments.

[0465] Figure 16 is a schematic diagram of a chip system 1600 provided in an embodiment of the present application, as shown in Figure 16. The chip system 1600 (or it can also be called a processing system) includes a logic circuit 1610 and an input / output interface (input / output interface) 1620. The logic circuit is used to couple with the input interface and transmit data parameters through the input / output interface to execute the method in the above method embodiment. The device installed with the chip system 1600 can implement the method and function of the embodiment of the present application. For example, the logic circuit 1610 can be a processing circuit in the chip system 1600, which realizes the control of the device installed with the chip system 1600, and can also be coupled to a storage unit to call the instructions in the storage unit so that the device can implement the method and function of the embodiment of the present application. The input / output interface 1620 can be an input and output circuit in the chip system 1600, which outputs the information processed by the chip system 1600, or inputs the data or signaling information to be processed into the chip system 1600 for processing.

[0466] As a solution, the chip system 1600 is used to implement the operations performed by the data transmission device (such as the source base station, the target base station, the first base station, the second base station or the core network) in the above method embodiment.

[0467] For example, the logic circuit 1610 is used to implement the processing-related operations performed by the source base station, target base station, first base station, second base station or core network in the above method embodiments, and the input / output interface 1620 is used to implement the sending and receiving-related operations performed by the source base station, target base station, first base station, second base station or core network in the above method embodiments.

[0468] An embodiment of the present application also provides a computer-readable storage medium on which computer instructions are stored for implementing the method executed by a data transmission device (such as a source base station, a target base station, a first base station, a second base station or a core network) in the above method embodiment.

[0469] For example, when the computer program is executed by a computer, the computer can implement the method performed by the data transmission device (such as the source base station, target base station, first base station, second base station or core network) in the above method embodiment.

[0470] An embodiment of the present application also provides a computer program product comprising instructions, which, when executed by a computer, enables the computer to implement the method performed by a data transmission device (such as a source base station, a target base station, a first base station, a second base station or a core network) in the above method embodiment.

[0471] The explanation of the relevant contents and beneficial effects of any of the above-mentioned devices can be referred to the corresponding method embodiments provided above, which will not be repeated here.

[0472] It should be understood that the processor mentioned in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0473] It should also be understood that the memory mentioned in the embodiments of the present application may be a volatile memory and / or a non-volatile memory. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM). For example, RAM can be used as an external cache. By way of example and not limitation, RAM may include the following forms: 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 rambus RAM (DR RAM).

[0474] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, the memory (storage module) can be integrated into the processor.

[0475] It should also be noted that the memory described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0476] Those skilled in the art will appreciate that the units and 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 performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel may use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of protection of this application.

[0477] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0478] Units described as separate components may or may not be physically separate, and 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 these units may be selected to implement the solutions provided in this application based on actual needs.

[0479] In addition, each functional unit in each embodiment of the present application may be integrated into one unit, each unit may exist physically separately, or two or more units may be integrated into one unit.

[0480] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When software is used for implementation, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function according to the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. For example, the computer can be a personal computer, a server, or a network device, etc. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website, computer, server or data center to another website, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state disk (SSD)). For example, the aforementioned available medium may include, but is not limited to, various media that can store program code, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0481] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A data transmission method, characterized in that: The method is applied to a source base station during a terminal device switching process, and includes: Sending a first switching request, where the first switching request includes a quality of service (QoS) parameter of a protocol data unit (PDU) set of the terminal device; Receiving first indication information, where the first indication information is used to indicate a processing capability of a target base station for the PDU set during a handover of the terminal device; Perform a switching operation according to the first indication information.

2. The method according to claim 1, characterized in that The QoS parameters include one or more of a protocol data unit set delay budget PSDB, a protocol data unit set error rate PSER, and a protocol data unit set integrity information PSIHI.

3. The method according to claim 1 or 2, characterized in that: The performing the switching operation according to the first indication information includes: When the first indication information indicates that the target base station has the processing capability of the PDU set, a first cache data packet is sent, where the first cache data packet includes relevant information of the PDU set.

4. The method according to claim 1 or 2, characterized in that: The performing the switching operation according to the first indication information includes: When the first indication information indicates that the target base station does not have the processing capability of the PDU set, a second cached data packet is sent, and the second cached data packet does not include relevant information of the PDU set; or, a new target base station is determined; or, a second switching request is sent to the target base station, and the second switching request does not include QoS parameters of the PDU set.

5. A data transmission method, characterized in that: The method is applied to a source base station where a terminal device is located, and includes: Sending a first capability query message, where the first capability query message is used to query the processing capability of at least one candidate base station for a protocol data unit PDU set, and the at least one candidate base station will be used for the terminal device switching process; receiving second indication information, where the second indication information is used to indicate a processing capability of the at least one candidate base station for the PDU set; Perform a switching operation according to the second indication information.

6. The method according to claim 5, characterized in that The performing the switching operation according to the second indication information includes: The candidate base station indicated by the second indication information and having the processing capability of the PDU set is determined as the target base station in the terminal device switching process.

7. The method according to claim 5, characterized in that The performing the switching operation according to the second indication information includes: When one of the at least one candidate base stations is determined as the target base station in the terminal device switching process, if the target base station does not have the processing capability of the PDU set, third cache data is sent, and the third cache data does not include relevant information of the PDU set.

8. A data transmission method, characterized in that: The method is applied to a first base station, comprising: Determine third indication information, where the third indication information is used to indicate capability information of the first base station for a low latency, low loss and scalable throughput L4S mechanism; When the trigger condition is met, the third indication information is sent to the core network.

9. The method according to claim 8, characterized in that The third indication information is used to indicate whether the first base station has both an explicit congestion notification (ECN) marking capability and a congestion information reporting capability.

10. The method according to claim 8, characterized in that The third indication information is used to indicate whether the first base station has ECN marking capability and congestion information reporting capability respectively.

11. The method according to claim 8, characterized in that The third indication information is used to indicate whether the first base station has an ECN marking capability or a congestion information reporting capability.

12. The method according to any one of claims 8 to 11, characterized in that Before determining the third indication information, the method further includes: receiving a first capability reporting request, where the first capability reporting request is used to request capability information of the first base station for the L4S mechanism; When the trigger condition is met, sending the third indication information includes: In response to the first capability reporting request, the third indication information is sent.

13. The method according to any one of claims 8 to 11, characterized in that Before determining the third indication information, the method further includes: receiving a first start message, where the first start message is used to instruct the first base station to mark an ECN and / or start a congestion information reporting operation; When the trigger condition is met, sending the third indication information includes: When the first base station has or does not have the ECN marking capability and / or the congestion information reporting capability, the third indication information is sent.

14. A data transmission device, characterized in that: The device comprises a transceiver unit and a processing unit: The transceiver unit is used to send a first switching request, where the first switching request includes a quality of service QoS parameter of a protocol data unit PDU set of the terminal device; The transceiver unit is used to receive first indication information, where the first indication information is used to indicate the processing capability of the target base station for the PDU set during the switching process of the terminal device; The processing unit is used for performing a switching operation according to the first indication information.

15. The device according to claim 14, characterized in that The QoS parameters include one or more of a protocol data unit set delay budget PSDB, a protocol data unit set error rate PSER, and a protocol data unit set integrity information PSIHI.

16. The device according to claim 14 or 15, characterized in that The processing unit is specifically used for: When the first indication information indicates that the target base station has the processing capability of the PDU set, the transceiver unit is controlled to send a first cache data packet, where the first data cache packet includes relevant information of the PDU set.

17. The device according to claim 14 or 15, characterized in that The processing unit is specifically used for: When the first indication information indicates that the target base station does not have the processing capability of the PDU set, controlling the transceiver unit to send a second cache data packet, wherein the second cache data packet does not include relevant information of the PDU set; Alternatively, a new target base station is determined; or alternatively, the transceiver unit is controlled to send a second switching request to the target base station, wherein the second switching request does not include the QoS parameters of the PDU set.

18. A data transmission device, characterized in that: The device comprises a transceiver unit and a processing unit: The transceiver unit is used to send a first capability query message, where the first capability query message is used to query the processing capability of at least one candidate base station for a protocol data unit PDU set, and the at least one candidate base station will be used for the terminal device switching process; The transceiver unit is used to receive second indication information, where the second indication information is used to indicate the processing capability of the at least one candidate base station for the PDU set; The processing unit is configured to perform a switching operation according to the second indication information.

19. The device according to claim 18, characterized in that The processing unit is specifically used for: The candidate base station indicated by the second indication information and having the processing capability of the PDU set is determined as the target base station in the terminal device switching process.

20. The device according to claim 18, characterized in that The processing unit is specifically configured to include: When one of the at least one candidate base stations is determined as the target base station in the terminal device switching process, if the target base station does not have the processing capability of the PDU set, the transceiver unit is controlled to send third cache data, and the third cache data does not include relevant information of the PDU set.

21. A data transmission device, characterized in that: The device comprises a processing unit and a transceiver unit: The processing unit is used to determine third indication information, where the third indication information is used to indicate capability information of the first base station for a low latency, low loss and scalable throughput L4S mechanism; The transceiver unit is used to send the third indication information to the core network when a trigger condition is met.

22. The device according to claim 21, characterized in that The third indication information is used to indicate whether the first base station has both an explicit congestion notification (ECN) marking capability and a congestion information reporting capability.

23. The device according to claim 21, characterized in that The third indication information is used to indicate whether the first base station has ECN marking capability and congestion information reporting capability respectively.

24. The device according to claim 21, characterized in that The third indication information is used to indicate whether the first base station has an ECN marking capability or a congestion information reporting capability.

25. The device according to any one of claims 21 to 24, characterized in that Before the processing unit is used to determine the third indication information, the transceiver unit is further used to: receiving a first capability reporting request, where the first capability reporting request is used to request capability information of the first base station for the L4S mechanism; The transceiver unit is specifically configured to send the third indication information in response to the first capability reporting request.

26. The device according to any one of claims 21 to 24, characterized in that Before the processing unit is used to determine the third indication information, the transceiver unit is further used to: receiving a first start message, where the first start message is used to instruct the first base station to mark an ECN and / or start a congestion information reporting operation; The transceiver unit is specifically configured to send the third indication information when the first base station has or does not have the ECN marking capability and / or the congestion information reporting capability.

27. A data transmission device, characterized in that: The device comprises a processor, the processor is coupled to a memory, the memory is used to store a computer program or instruction, and the processor is used to execute the computer program or instruction in the memory, so that the device performs the method according to any one of claims 1 to 13.

28. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program or instructions, and when the computer program or instructions are executed on a computer, the computer is caused to execute the method according to any one of claims 1 to 13.

29. A chip, characterized in that: The chip is coupled to a memory and is used to read and execute program instructions stored in the memory to implement the method according to any one of claims 1 to 13.

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