Data transmission method, network device and computer readable storage medium

Abstract

The present application relates to the field of communication technology, and aims to solve the problem that the frequent transmission of small data packets leads to large signaling overhead of network devices, and provides a data transmission method, a network device and a computer-readable storage medium. Among them, the data transmission method is applied to the network device, and when the network device is an anchor base station, the data transmission method includes: obtaining downlink data or signaling for the user device from the core network. Among them, the user equipment is in an RRC inactive state, and the downlink data or signaling carries first configuration information, and the first configuration information is used to determine whether to perform user equipment context migration. Determine whether to perform user equipment context migration according to the first configuration information. If it is determined to perform user equipment context migration, the user equipment context is migrated to the serving base station, and downlink data or signaling is sent to the serving base station.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a data transmission method, a network device, and a computer-readable storage medium. Background Art

[0002] In the fifth-generation (5th-Generation, 5G) New Radio (NR) network, in order to improve the efficiency of frequent transmission of small data packets, a Radio Resource Control (RRC) state is introduced: RRC Inactive state. When the network device sends an RRC Release message carrying a Suspend configuration to a User Equipment (UE) in the RRC Connected state, the UE will be instructed to enter the RRC Inactive state. When the UE is in the RRC Inactive state, the UE context (UE Context) is suspended on both the UE side and the network device side. In this way, when the UE needs to send data / signaling, it can first send an RRC Resume Request message to the network device, so that the UE switches from the RRC Inactive state to the RRC Connected state, and then the UE can send data / signaling to the network device. If data / signaling is transmitted frequently, the user equipment will frequently switch states, resulting in a large proportion of signaling overhead. Summary of the invention

[0003] The embodiments of the present application provide a data transmission method, a network device, and a computer-readable storage medium to reduce the signaling overhead caused by the state switching of a user device and improve the data transmission efficiency.

[0004] The first aspect of the present application provides a data transmission method, which is applied to an anchor base station, and the data transmission method includes: obtaining downlink data or signaling for a user equipment from a core network. The user equipment is in an RRC inactive state, and the downlink data or signaling carries first configuration information, and the first configuration information is used to determine whether to perform user equipment context migration. Determine whether to perform user equipment context migration according to the first configuration information. If it is determined to perform user equipment context migration, migrate the user equipment context to a serving base station, and send downlink data or signaling to the serving base station.

[0005] By adopting this technical solution, when the anchor base station receives downlink data or signaling from the core network, it determines whether to perform user equipment context migration according to the first configuration information carried by the downlink data or signaling, which can save signaling resources and avoid wasting signaling resources by performing user equipment context migration when it is not necessary. When it is determined to perform user equipment context migration, the anchor base station migrates the user equipment context and sends downlink data or signaling to the serving base station, which can transmit downlink data or signaling during the period when the user equipment is in the RRC inactive state without switching the user equipment from the RRC inactive state to the RRC connected state, thereby reducing the signaling overhead caused by the state switching of the user equipment, reducing service delays, and improving data transmission efficiency.

[0006] In one implementation manner, sending downlink data or signaling to the serving base station includes: sending downlink data or signaling to the serving base station in a mobile terminated small data packet transmission (MT-SDT) manner.

[0007] By adopting this technical solution, when small data packets are frequently received from the core network, the anchor base station transmits downlink data or signaling via the MT-SDT mode, and can directly transmit small data packets when the user equipment is in the RRC inactive state without frequently switching the RRC state of the user equipment, thereby reducing the signaling overhead caused by the state switching of the user equipment, reducing service delays, and improving data transmission efficiency.

[0008] In another embodiment, the first configuration information includes at least one of the following information: auxiliary information, radio bearer, and data packet size. The auxiliary information is used to indicate the small data packet transmission SDT for the data to be transmitted, and the auxiliary information includes at least one of the following information: user equipment's contract data, capabilities, data transmission statistics, data or signaling service characteristics, and first indication information related to SDT. The first indication information is used to indicate the triggering of mobile termination of small data packet transmission.

[0009] By adopting this technical solution, before transmitting downlink data or signaling, the anchor base station determines whether to perform user equipment context migration based on at least one of the auxiliary information, wireless bearer and data packet size, which can save signaling resources and avoid wasting signaling resources by performing user equipment context migration when it is not necessary.

[0010] In another embodiment, before migrating the user equipment context to the serving base station, the data transmission method further includes: receiving a user equipment context retrieval request message from the serving base station, the retrieval user equipment context request message is used to request the user equipment context. Migrating the user equipment context to the serving base station includes: sending a user equipment context retrieval response message to the serving base station, the retrieval user equipment context response message carries the user equipment context. After migrating the user equipment context to the serving base station, the data transmission method further includes: receiving a user equipment context release message from the serving base station, and releasing the stored user equipment context, the user equipment context release message is used to indicate the release of the stored user equipment context.

[0011] With this technical solution, when the anchor base station determines to perform user equipment context migration, the user equipment context migration is passively triggered, that is, after receiving a user equipment context retrieval request message from the serving base station, the user equipment context is sent to the serving base station.

[0012] In another implementation, the UE context retrieval response message further carries at least one of the following information: a data packet size and frequency allowed to be transmitted, and auxiliary information, where the auxiliary information is used to perform SDT indication on the data to be transmitted.

[0013] In another embodiment, before migrating the user equipment context to the serving base station, the data transmission method further includes: sending a paging message to the serving base station, the paging message carrying first indication information. The first indication information is used to indicate triggering MT-SDT. After migrating the user equipment context to the serving base station, the data transmission method further includes: receiving a user equipment context release message from the serving base station, and releasing the stored user equipment context. The user equipment context release message is used to indicate the release of the stored user equipment context.

[0014] With this technical solution, when the anchor base station determines to perform user equipment context migration, it actively triggers the user equipment context migration, that is, directly sends the user equipment context to the serving base station.

[0015] In another embodiment, the data transmission method further includes: if it is determined that the user equipment context migration is not to be performed, receiving a user equipment context retrieval request message from the serving base station, and sending a user equipment context retrieval failure message and downlink data or signaling to the serving base station. The user equipment context retrieval request message is used to request the user equipment context, and the user equipment context retrieval failure message is used to notify the serving base station that all user equipment contexts have not been obtained.

[0016] With this technical solution, when it is determined not to perform user equipment context migration, the anchor base station sends a user equipment context retrieval failure message to the serving base station to notify that all user equipment contexts will not be migrated, thereby enabling fast transmission of downlink data or signaling.

[0017] In another embodiment, the data transmission method further includes: if it is determined that the user equipment context migration is not to be performed, sending a user equipment partial context setting request message to the serving base station, the user equipment partial context setting request message carries second configuration information, and the second configuration information is used to configure the data transmission mode in the scenario where the user equipment context migration is not performed. Send part of the user equipment context and downlink data or signaling to the serving base station according to the second configuration information.

[0018] By adopting this technical solution, when it is determined that no context migration is to be performed, the anchor base station sends a user equipment partial context setting request message to the serving base station, and sends a partial user equipment context according to the second configuration information carried in the user equipment partial context setting request message to meet the data transmission requirements of the network.

[0019] In another implementation, the data transmission mode includes MT-SDT or SDT.

[0020] In another embodiment, the second configuration information includes a paging message, a part of the user equipment context and a protocol data unit of a packet data convergence protocol layer. The paging message carries second indication information, and the second indication information is used to indicate that MT-SDT is not triggered. The protocol data unit of the packet data convergence protocol layer is used to store downlink data or signaling.

[0021] By adopting this technical solution, the anchor base station sends part of the user equipment context and the protocol data unit of the packet data convergence protocol layer together with the paging message, which can not only meet the data transmission requirements of the network, but also reduce the signaling overhead.

[0022] The second aspect of the present application provides a data transmission method, which is applied to a serving base station, and the data transmission method includes: obtaining downlink data or signaling for a user equipment from an anchor base station. The user equipment is in an RRC inactive state, and the downlink data or signaling carries first configuration information, and the first configuration information is used to determine whether to perform user equipment context migration. If the anchor base station determines to perform user equipment context migration, the user equipment context is received from the anchor base station, and downlink data or signaling is sent to the user equipment.

[0023] By adopting this technical solution, when the serving base station receives downlink data or signaling from the anchor base station, it determines whether the anchor base station performs user equipment context migration according to the first configuration information carried by the downlink data or signaling, which can save signaling resources and avoid wasting signaling resources by performing user equipment context migration when it is not necessary. When the anchor base station determines to perform user equipment context migration, it receives the user equipment context and downlink data or signaling from the anchor base station, and sends downlink data or signaling to the user equipment. It can transmit downlink data or signaling during the period when the user equipment is in the RRC inactive state without switching the user equipment from the RRC inactive state to the RRC connected state, thereby reducing the signaling overhead caused by the state switching of the user equipment, reducing service delays, and improving data transmission efficiency.

[0024] In one embodiment, after sending downlink data or signaling to the user equipment, the data transmission method further includes: sending an RRC release message to the user equipment, the RRC release message is used to indicate that the user equipment enters an RRC inactive state or an idle state. Alternatively, sending an RRC recovery message to the user equipment, the RRC recovery message is used to indicate that the user equipment enters an RRC connected state.

[0025] With this technical solution, when downlink data or signaling transmission is completed, the serving base station can send an RRC release message or an RRC recovery message to the user equipment according to actual needs, thereby instructing the user equipment to enter a corresponding state.

[0026] It can be understood that the data transmission method provided in the second aspect of the present application is applied to the service base station, which is roughly the same as the data transmission method provided in the first aspect of the present application.

[0027] A third aspect of the present application provides a network device, which includes a memory and a processor, and the processor calls a computer program or code stored in the memory to execute the data transmission method of an embodiment of the present application.

[0028] It can be understood that the network device can be an anchor base station or a serving base station. When the network device is an anchor base station, the data transmission method provided in the first aspect of the present application can be executed. When the network device is a serving base station, the data transmission method provided in the second aspect of the present application can be executed.

[0029] A fourth aspect of the present application provides a computer-readable storage medium for storing a computer program or instruction. When the computer program or instruction is executed by a processor, the data transmission method of the embodiment of the present application is implemented.

[0030] It can be understood that the specific implementation methods and technical effects of the network device provided in the third aspect of the present application and the computer-readable storage medium provided in the fourth aspect of the present application can refer to the data transmission methods provided in the first and second aspects of the present application, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the 5G network architecture.

[0032] Figure 2 The present invention is a schematic diagram of an information interaction scenario in which a user equipment migrates from an RRC inactive state to an RRC connected state in an example.

[0033] Figure 3 This is a schematic diagram of an information interaction scenario in another example in which a user equipment migrates from an RRC inactive state to an RRC connected state.

[0034] Figure 4a It is a schematic diagram of an information interaction scenario of a data transmission method in a scenario where an anchor base station performs user equipment context migration.

[0035] Figure 4b It is a schematic diagram of an information interaction scenario of a data transmission method in a scenario where an anchor base station does not perform user equipment context migration.

[0036] Figure 5 It is a schematic diagram of an information interaction scenario of another data transmission method in a scenario where an anchor base station performs user equipment context migration.

[0037] Figure 6 It is a schematic diagram of an information interaction scenario of another data transmission method in a scenario where an anchor base station performs user equipment context migration.

[0038] Figure 7 It is a schematic diagram of an information interaction scenario of another data transmission method in a scenario where an anchor base station performs user equipment context migration.

[0039] Figure 8 It is a schematic diagram of an information interaction scenario of another data transmission method in a scenario where an anchor base station performs user equipment context migration.

[0040] Fig. 9 It is a schematic diagram of an information interaction scenario of another data transmission method in a scenario where an anchor base station performs user equipment context migration.

[0041] Fig.10 It is a schematic diagram of an information interaction scenario of another data transmission method in a scenario where an anchor base station performs user equipment context migration.

[0042] Fig.11It is a schematic diagram of an information interaction scenario of another data transmission method in a scenario where an anchor base station does not perform user equipment context migration.

[0043] Fig.12 It is a schematic diagram of an information interaction scenario of another data transmission method in a scenario where an anchor base station does not perform user equipment context migration.

[0044] Fig.13 It is a schematic diagram of an information interaction scenario of another data transmission method in a scenario where an anchor base station does not perform user equipment context migration.

[0045] Fig.14 It is a schematic diagram of the structure of a network device according to one embodiment of the present application.

[0046] Fig.15 It is a schematic diagram of the structure of a network device according to another embodiment of the present application.

[0047] Fig.16 It is a structural diagram of a user equipment according to one embodiment of the present application. DETAILED DESCRIPTION

[0048] It should be noted that in the embodiments of the present application, "at least one" refers to one or more, and "more than one" refers to two or more than two. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The terms "first", "second", "third", "fourth", etc. (if any) in the specification, claims and drawings of this application are used to distinguish similar objects, rather than to describe a specific order or sequence.

[0049] It should also be noted that the method disclosed in the embodiments of the present application or the method shown in the flowchart includes one or more steps for implementing the method. Without departing from the scope of the claims, the execution order of multiple steps can be interchangeable with each other, and some of the steps can also be deleted.

[0050] Some of the terms used in the embodiments of the present application are explained below to facilitate understanding by those skilled in the art.

[0051] 1. User Equipment (UE)

[0052] User equipment may also be referred to as a mobile terminal (Mobile Terminal), mobile user equipment, etc., and may communicate with one or more core networks via a radio access network (Radio Access Network, RAN).

[0053] 2. Network equipment

[0054] Network equipment refers to equipment deployed in a wireless access network to provide wireless communication functions for user equipment. Network equipment may include base stations, and base stations may include macro base stations, micro base stations, relay stations, access point base station controllers, or transmission reception points (TRP), etc. In different networks, the specific names of base stations are different. For example, in the Long Term Evolution (LTE) network, it is called an evolved Node B (eNB), and in subsequent evolution systems, it may also be called a new radio Node B (gNB). In this article, a base station may act as a serving base station (Serving gNB) and / or an anchor base station (Anchor gNB). Among them, a serving base station refers to a base station that currently serves a user equipment, and an anchor base station refers to a base station that served the user equipment last time.

[0055] 3. RAN based Notification Area (RNA)

[0056] The notification area based on the radio access network is also called the radio access network notification area (RNA), which may include one or more cells. If the RNA includes multiple cells, the multiple cells may be cells controlled by one or more base stations (e.g., eNB and / or gNB).

[0057] 4. Core Network (CN)

[0058] The user equipment transmits data with the core network through the network equipment, for example, transmits data with the access and mobility management function (AMF) or user plane function (UPF) of the core network.

[0059] 5. Radio Resource Control (RRC) Status

[0060] Figure 1 Taking the network service architecture of the 5G system as an example, the interaction between network functions and entities and the corresponding interfaces are demonstrated.

[0061] See also Figure 1In the 5G network architecture (service-based architecture, SBA), network functions and entities mainly include: user equipment (UE), access network (access network, AN) or radio access network (RAN), user plane function (UPF), data network (data network, DN), access management function (AMF), session management function (session management function, SMF), authentication server function (authentication server function, AUSF), policy control function (policy control function, PCF), application function (application function, AF), network slice selection function (network slice selection function, NSSF), unified data management (unified data management, UDM), network exposure function (network exposure function, NEF) and network storage function (network repository function, NRF).

[0062] A network function can be implemented as a network element running on dedicated hardware, as a software instance running on dedicated hardware, or as a virtual function instantiated on a suitable platform, such as a cloud infrastructure.

[0063] The following is a detailed introduction to the main functions of some network elements.

[0064] AN / RAN: AN / RAN may include various forms of network equipment. AN / RAN is mainly responsible for radio resource management on the air interface side, uplink and downlink data classification, quality of service (QoS) management, data compression and encryption, signaling processing with control plane network elements or data forwarding with user plane function network elements. The specific form and structure of AN / RAN are not limited in the embodiments of the present application.

[0065] UPF: Mainly responsible for packet routing and forwarding, as well as QoS processing or billing information statistics of user plane data. The transmission resources and scheduling functions that provide services to UEs in UPF are managed and controlled by SMF.

[0066] DN: DN is a network used to transmit data. For example, DN can be a carrier service network, Internet access, or a third-party service network.

[0067] exist Figure 1In the 5G network shown, the user equipment has three RRC states: RRC connected state, RRC idle state and RRC inactive state. The three RRC states can be converted to each other. In this article, the conversion between the three RRC states can also be referred to as "state switching" or "state migration".

[0068] RRC connected state, also referred to as connected state. In this document, "connected state" and "RRC connected state" are the same concept. When the user equipment is in the connected state, the user equipment has established an RRC connection with the network and data transmission can be performed.

[0069] RRC Idle state, also referred to as idle state. In this article, "idle state" and "RRC idle state" are the same concept. When the user equipment is in idle state, the user equipment has not established an RRC connection with the network, and the base station has not stored the context of the user equipment. If the user equipment needs to enter the RRC connected state from the RRC idle state, it needs to initiate the RRC connection establishment process.

[0070] RRC inactive state, also referred to as inactive state for short. In this article, "inactive state" and "RRC inactive state" are the same concept. When the user equipment is in the inactive state, the user equipment previously entered the RRC connected state at the anchor base station, and then the anchor base station released the RRC connection, but the anchor base station saved the context of the user equipment. If the user equipment needs to enter the RRC connected state again from the RRC inactive state, it is necessary to initiate the RRC connection recovery process, or the RRC connection re-establishment process, at the serving base station. Because the user equipment may be moving, the serving base station and the anchor base station may be the same base station or different base stations.

[0071] 6. Small Data Transmission (SDT)

[0072] In an embodiment of the present application, a data packet whose data volume is less than a preset data volume threshold may be referred to as a small data packet. In a traditional communication network, a user device in an idle state or an inactive state needs to first transmit multiple control signalings with a base station before entering a connected state, and then transmit data or signaling with the base station. In a communication network such as machine type communication (MTC), a user device will frequently send some small data packets to a base station, which will cause a user device in an idle state or an inactive state to frequently switch to a connected state, resulting in a large amount of signaling overhead and increasing the power consumption of the base station.

[0073] In response to this situation, there is currently a method in which the user equipment can transmit data without entering a connected state, namely, a small data packet transmission (SDT) method. The small data packet transmission method means that after the user equipment determines that the data packet to be transmitted is a small data packet, the small data packet is integrated into some control signaling, and then the small data packet is transmitted to the base station through these control signaling. Alternatively, the user equipment uses its stored context to transmit the small data packet to the base station. The small data packet transmission method may include an Early Data Transmission (EDT) method, a two-step random access or a Pre-Configured Uplink Resource (PUR) method, etc.

[0074] 7. Mobile Terminated (MT)

[0075] Mobile termination, also known as mobile termination, involves mobile messages routed from core network equipment (such as AMF) or network equipment (such as base stations) and sent to user equipment. Mobile termination also refers to voice calls terminated to user equipment from another mobile user, the Public Switch Telephone Network (PSTN) or other networks.

[0076] The term "termination" means that the message delivery is terminated at the user equipment. This term also describes the communication between the Short Message Service Center (SMSC) and the user equipment, and between the Mobile Switching Center (MSC) and the user equipment.

[0077] 8. Mobile Terminated-Small Data Transmission (MT-SDT)

[0078] MT-SDT refers to a small data packet transmission method that terminates at the user equipment, also known as mobile called small data packet transmission. When the user equipment receives downlink data and / or signaling from the network equipment through the MT-SDT method, it can reduce signaling overhead and UE power consumption by not switching to the RRC connection state, and reduce latency by allowing fast transmission of small data packets (such as small data packets used for positioning).

[0079] Corresponding to MT-SDT is Mobile Originating-Small Data Transmission (MO-SDT), also known as Mobile Originating Small Data Transmission. MO-SDT refers to the small data packet transmission initiated by the user equipment. When the user equipment sends uplink data and / or signaling to the network equipment through MO-SDT, the small data packet can be transmitted in the RRC inactive state, thereby reducing signaling overhead and UE power consumption.

[0080] 9. User Equipment Context (UE Context)

[0081] During the communication process between the user equipment and the network device, the network device creates a record for the user equipment, which is called a user equipment context (UE Context).

[0082] The UE context is used to store the device information of the UE, such as the mobile phone number, device number, IP address, Quality of Service (QoS) parameters, etc. The UE context is used to maintain communication with the UE and process services for the UE during the communication process. In this article, "UE context" is referred to as "Context".

[0083] 10. Radio Bearer (RB)

[0084] Radio bearers include data radio bearers (DRB) and signaling radio bearers (SRB). DRB types include DRB1, DRB2, etc., and SRB types include SRB1, SRB2, etc.

[0085] 11. RAN-based Paging

[0086] Radio access network-based paging means that the network equipment initiates paging within the radio access network notification area (RNA) to determine the cell where the user equipment is located. When the network equipment receives downlink data / signaling from the core network, the radio access network paging (RAN Paging) message is triggered. In this article, "RAN-based Paging", "RAN Paging" and "Paging" are the same concept.

[0087] 12. Xn interface

[0088] The Xn interface refers to the interface for data transmission between two base stations, for example, data transmission between a serving base station and an anchor base station is performed via the Xn interface. The Xn interface may include, but is not limited to, a user plane interface Xn-U, a control plane interface Xn-C, etc. Among them, the user plane interface Xn-U mainly provides data forwarding functions and flow control functions. The control plane interface Xn-C mainly provides functions such as Xn interface management, UE mobility management, and dual connection implementation.

[0089] 13. NG interface

[0090] The NG interface refers to the interface for data transmission between the radio access network and the core network. The NG interface may include, but is not limited to, the user plane interface NG-U, the control plane interface NG-C, etc. Among them, the user plane interface NG-U is the interface between the radio access network and the user plane function (UPF) of the core network. The control plane interface NG-C is the interface between the radio access network and the control plane function (AMF) of the core network.

[0091] It can be understood that the 5G New Radio (NR) network includes RRC connected state and RRC idle state. In order to improve the efficiency of frequent transmission of small data packets, the 5G NR network introduces the RRC inactive state.

[0092] For example, the base station sends an RRC release message carrying a suspend configuration to a user equipment (UE) in the RRC connected state to instruct the UE to enter the RRC inactive state. When the UE is in the RRC inactive state, the UE's context is suspended on both the terminal side and the base station side. When data / signaling needs to be sent, the UE will trigger the RRC resume request process to switch the UE from the RRC inactive state to the RRC connected state, and then the UE can send data / signaling.

[0093] For example, Figure 2 It is a schematic diagram of an information interaction scenario in which a UE migrates from an RRC inactive state to an RRC connected state when data and / or signaling needs to be sent.

[0094] like Figure 2 As shown, it can be understood that when the UE is in the RRC inactive state, if the UE needs to send data / signaling, the user equipment (UE) sends an RRC resume request (RRC Resume Request) message to the serving base station (see S201) to request switching to the RRC connected state.

[0095] The serving base station sends a Retrieve UE Context Request message to the anchor base station (see S202 ) to obtain the user equipment context (UE Context).

[0096] In response to the retrieve UE context request message, the anchor base station sends a retrieve UE context response message to the serving base station (see S203 ), and the retrieve UE context response message carries the UE context (UE Context).

[0097] After acquiring the context, the serving base station sends an RRC resume (RRC Resume) message to the user equipment (see S204) to notify the user equipment to switch to the RRC connected state.

[0098] After the user equipment switches from the RRC inactive state to the RRC connected state, it sends an RRC resume complete (RRC ResumeComplete) message to the serving base station (see S205) to notify the serving base station that the user equipment has switched to the RRC connected state.

[0099] The serving base station sends an Xn-U interface address indication message to the anchor base station (see S206), and the Xn-U interface address indication message carries the data forwarding address. The serving base station provides the data forwarding address to the anchor base station to prevent the loss of downlink data cached by the anchor base station during data transmission.

[0100] The serving base station sends a path switch request (Path Switch Request) message to the core network (eg, AMF) (see S207) to request that the downlink termination point of the NG interface transmission bearer be switched to a new termination point.

[0101] In response to the path switch request, the core network sends a path switch response (Path Switch Response) message to the serving base station (see S208) to notify the serving base station that the downlink of the NG interface transmission bearer has been switched to a new termination point.

[0102] The serving base station sends a UE Context Release message to the anchor base station (see S209 ) to instruct the anchor base station to release its cached context.

[0103] For another example, see Figure 3 , Figure 3It is a schematic diagram of another information interaction scenario in which the UE migrates from the RRC inactive state to the RRC connected state when there is data and / or signaling to be sent.

[0104] like Figure 3 As shown, it can be understood that when the UE is in an RRC inactive state, if the anchor base station receives downlink data / signaling from the core network, the anchor base station pages the user equipment in the radio access network notification area (RAN-based Notification Area, RNA), and can directly send a paging message to the user equipment, or forward the paging message to the user equipment through the serving base station. For example, the anchor base station sends a radio access network paging (RAN Paging) message to the serving base station (see S301) to notify the serving base station to page the user equipment in the radio access network notification area (RNA).

[0105] The serving base station sends a radio access network paging message to the user equipment (see S302). It can be understood that the radio access network paging message may include an inactive radio network temporary identity (Inactive Radio Network Temporary Identity, I-RNTI). The serving base station can page the user equipment (Paging UE) over the air interface through the I-RNTI. Among them, the I-RNTI is used to identify the UE to indicate paging for a specific UE.

[0106] When the user equipment is successfully paged, the user equipment triggers the RRC recovery request process (see S303, i.e. Figure 2 Steps S201 to S209 in the figure), switching from the RRC inactive state to the RRC connected state (Resume from RRC Inactive State), and then receiving downlink data / signaling (not shown in the figure).

[0107] After the user equipment successfully receives the downlink data / signaling, the serving base station sends a release context message to the user equipment, and the user equipment migrates from the RRC connected state to the RRC inactive state again.

[0108] like Figure 2 and Figure 3 As shown, if data / signaling is frequently transmitted, the user equipment will frequently perform state transitions, resulting in a large proportion of signaling overhead.

[0109] In addition, for the Mobile Termination (MT) scenario, there is currently no solution on how to trigger the transmission of small data packets in the downlink.

[0110] Based on this, the present application provides a data transmission method, a network device and a computer storage medium, which are intended to trigger the MT-SDT mechanism for UE in an RRC inactive state, that is, to trigger MT-SDT when the UE is in an RRC inactive state to receive a small data packet of the initial downlink, and to transmit a small data packet of the subsequent uplink or downlink. In a mobile terminating (MT) scenario, a small data packet transmission (SDT) of the downlink is triggered to notify the user equipment to receive data / signaling in an RRC inactive state, thereby reducing the signaling overhead caused by the state migration of the user equipment, reducing the number of signaling between the interfaces of the serving base station and the anchor base station, and reducing service delay.

[0111] It should be noted that when the user equipment (UE) switches from the RRC connected state to the RRC inactive state under the service of the anchor gNB, the anchor gNB will save the user equipment context (UE Context), which is the same as the user equipment context in the RRC connected state or is part of the user equipment context in the RRC connected state. Subsequently, the user equipment in the RRC inactive state moves within the notification area (RNA) based on the radio access network, and there are the following two scenarios.

[0112] Scenario 1: The user equipment enters the service range of the serving base station (Serving gNB), the user equipment receives the broadcast signal of the serving base station, and transmits data with the core network through the serving base station. When the anchor base station receives downlink data / signaling from the core network, the anchor base station triggers a radio access network paging (RAN Paging) message. When the paging message broadcast by the anchor base station within its service range does not receive a response from the user equipment, the paging message is sent to the serving base station, and the serving base station continues to broadcast the paging message. When the serving base station receives the response message from the user equipment, it can be determined that the user equipment is currently within the service range of the serving base station. In this way, the anchor base station needs to forward the downlink data / signaling to the user equipment through the serving base station.

[0113] Scenario 2: The user equipment is still in the service range of the anchor gNB. The user equipment continues to receive the broadcast signal of the anchor gNB and transmits data with the core network through the anchor gNB. In other words, the anchor gNB and the serving gNB are the same gNB. When the anchor gNB receives downlink data / signaling from the core network, the anchor gNB triggers a RAN Paging message. When the anchor gNB receives a response message from the user equipment, it can be determined that the user equipment is currently in the service range of the anchor gNB. At this point, the anchor gNB can directly send downlink data / signaling to the user equipment.

[0114] It can be understood that the difference between scenario 1 and scenario 2 is that in scenario 1, the anchor base station needs to forward downlink data / signaling to the user equipment through the serving base station. In scenario 2, the anchor base station and the serving base station are the same base station, so the anchor base station can directly send downlink data / signaling to the user equipment.

[0115] It can be understood that for the convenience of description, the following will take scenario one as an example, combined with the drawings in the embodiments of the present application, to clearly and completely describe the technical solution in the embodiments of the present application.

[0116] Specifically, Figure 4a As shown, Figure 4a The present invention is a schematic diagram of an information interaction scenario of a data transmission method in a scenario where an anchor base station performs user equipment context migration. When a user equipment in an RRC inactive state enters the service range of a serving base station, the data transmission method may include the following steps:

[0117] S401a, the anchor base station obtains downlink data / signaling (Downlink Signaling or Data) from the core network.

[0118] It should be noted that in the embodiments of the present application, the transmission mode of downlink data / signaling from the core network is the MT-SDT mode.

[0119] The downlink data / signaling may carry first configuration information, and the first configuration information is used to determine whether to perform user equipment context (UE Context) migration. The first configuration information may include auxiliary information, radio bearer (RadioBearer, RB) information and data packet size.

[0120] The auxiliary information is used to perform SDT indication on the data to be transmitted, so as to instruct the anchor base station to perform SDT. The auxiliary information may include the UE's subscription data, capabilities, data transmission statistics, data / signaling service characteristics and first indication information related to SDT.

[0121] Data service characteristics may include the frequency of single data packets / multiple data packets, the duration of a session, and the amount of data that lasts for a session.

[0122] Signaling service characteristics may include the frequency of signaling and the size of signaling data packets.

[0123] The first indication information is used to indicate triggering of MT-SDT.

[0124] The radio bearer information may include bearer information configured with at least one of the following capabilities: MT-SDT capability, MO-SDT capability, SDT capability.

[0125] The data packet size may be the size of all data packets included in the downlink data / signaling, or may be the size of a single data packet included in the downlink data / signaling.

[0126] S402a, the anchor base station determines whether to perform user equipment context (UE Context) migration.

[0127] It should be noted that Figure 4a The illustrated embodiment is described by taking user equipment context migration as an example.

[0128] It can be understood that the anchor base station can determine whether to perform user equipment context migration according to one or more parameters in the first configuration information.

[0129] In some embodiments, when at least one of the following conditions is met, the anchor base station determines to perform user equipment context migration.

[0130] Condition 1: executing the first implementation algorithm of the anchor base station, and performing user equipment context migration based on the first implementation algorithm.

[0131] The first implementation algorithm is used to indicate the migration of the user equipment context.

[0132] Condition 2: obtaining second indication information from the core network, where the second indication information is used to instruct to perform user equipment context migration.

[0133] Condition three: satisfying the first attribute requirement of service delay, and performing user equipment context migration based on the first attribute requirement of service delay.

[0134] The first attribute requirement is used to indicate the migration of the user equipment context. The attribute of the service delay refers to the maximum delay allowed for scheduling downlink data / signaling. When the maximum delay is greater than or equal to the delay threshold, the user equipment context migration is required. The delay threshold refers to the minimum delay that triggers the user equipment context migration.

[0135] In some other embodiments, when at least one of the following conditions is met, the anchor base station determines not to perform user equipment context migration.

[0136] Condition 1: executing the second implementation algorithm of the anchor base station, and not performing user equipment context migration based on the second implementation algorithm.

[0137] The second implementation algorithm is used to indicate not to migrate the user equipment context.

[0138] Condition 2: Obtain third indication information from the core network, where the third indication information is used to indicate not to perform user equipment context migration.

[0139] Condition three: satisfying the second attribute requirement of service delay, and not performing user equipment context migration based on the second attribute requirement of service delay.

[0140] The second attribute requirement is used to indicate that the user equipment context is not to be migrated. It can be understood that when the maximum delay allowed for scheduling downlink data / signaling is less than the delay threshold, the user equipment context does not need to be migrated.

[0141] For example, in the face of burst traffic, in order to reduce service delay, it is necessary to quickly send downlink data / signaling to the user equipment without performing user equipment context migration.

[0142] Condition 4: Obtain data transmission statistics information of the SDT service, where the data transmission statistics information is used to indicate that user equipment context migration is not performed.

[0143] For example, the data transmission statistical information includes traffic characteristics (Traffic Arrtribute), and based on the traffic characteristics, downlink data / signaling needs to be sent to the user equipment quickly without performing user equipment context migration.

[0144] S403, the anchor base station sends the user equipment context (UE Context) and downlink data / signaling to the serving base station in MT-SDT mode.

[0145] In this embodiment, when it is determined to perform user equipment context migration, the anchor base station executes step S403.

[0146] In some embodiments, when it is determined to perform user equipment context migration, the anchor base station may migrate the user equipment context (UE Context) within a radio access network valid area (RNA) and transmit downlink data / signaling to the serving base station.

[0147] In other embodiments, when it is determined to perform user equipment context migration, the anchor base station may wait to obtain a retrieve user equipment context request (Retrieve UE Context Request) message from the serving base station. After receiving the retrieve user equipment context request message, the anchor base station migrates the user equipment context (UE Context) within the radio access network effective area (RNA) and transmits downlink data / signaling to the serving base station.

[0148] S404, the serving base station saves the user equipment context (UE Context), and sends downlink data / signaling to the user equipment in MT-SDT mode.

[0149] In some embodiments, after receiving the user equipment context (UE Context) and downlink data / signaling, the serving base station performs path switching with the core network to switch the downlink carried by the NG interface transmission to a new termination point, for example, switching the downlink to the serving base station.

[0150] S405, the serving base station sends a user equipment context release (UE Context Release) message to the anchor base station in MT-SDT mode, to instruct the anchor base station to release its cached user equipment context (UE Context).

[0151] It can be understood that in this embodiment, the UE in the RRC inactive state moves within the radio access network notification area (RNA). When the UE is called, that is, there is downlink data / signaling that needs to be transmitted to the UE, the anchor base station first receives the downlink data / signaling from the core network, triggers the transmission of small data packets in the downlink, that is, transmits the downlink data / signaling in MT-SDT mode. Then, the anchor base station determines whether to perform user equipment context (UE Context) migration. When it is determined to perform user equipment context migration, the anchor base station sends the user equipment context and downlink data / signaling to the serving base station in MT-SDT mode. The serving base station saves the user equipment context and sends downlink data / signaling to the user equipment in MT-SDT mode. In this way, the downlink data / signaling from the core network is transmitted in MT-SDT mode. In the scenario of mobile called, the anchor base station can send downlink data / signaling to the serving base station during the UE is in the RRC inactive state, and then forward the downlink data / signaling to the UE through the serving base station, without the UE switching from the RRC inactive state to the RRC connected state. In this way, the number of signaling between the interfaces of the serving base station and the anchor base station can be reduced, and the signaling overhead caused by the state migration of the UE can be reduced, thereby reducing the service delay.

[0152] like Figure 4b As shown, Figure 4b This is a schematic diagram of an information interaction scenario of a data transmission method in a scenario where the anchor base station does not perform user equipment context migration. Figure 4b , the data transmission method may include the following steps:

[0153] S401b, the anchor base station obtains downlink data / signaling (Downlink Signaling or Data) from the core network.

[0154] The downlink data / signaling carries the first configuration information.

[0155] It can be understood that when the UE is called, the downlink data / signaling sent by the core network needs to be transmitted to the UE. At this time, the anchor base station first obtains the downlink data / signaling sent by the core network.

[0156] S402b, the anchor base station determines whether to perform user equipment context (UE Context) migration.

[0157] It should be noted that Figure 4b The illustrated embodiment is described by taking the case where no user equipment context migration is performed as an example.

[0158] In this embodiment, when receiving downlink data / signaling from the core network, the anchor base station can determine whether to perform user equipment context migration according to the first configuration information carried by the downlink data / signaling. Compared with the solution of performing user equipment context migration by default, this embodiment can be determined according to actual needs, which can save signaling resources and avoid wasting signaling resources by performing user equipment context migration when it is not necessary.

[0159] Understandably, Figure 4b Steps S401b to S402b in Figure 4a The same is true in steps S401a to S402a.

[0160] S406, the anchor base station obtains a Retrieve UEContext Request message from the serving base station.

[0161] In this embodiment, when it is determined that the user equipment context migration is not to be performed, the anchor base station executes step S406.

[0162] The user equipment context retrieval request message is used to request the user equipment context.

[0163] S407, the anchor base station responds to the Retrieve UE Context Request message by sending a Retrieve UE Context Failure message and downlink data or signaling to the serving base station in MT-SDT mode.

[0164] In this embodiment, since it is determined that user equipment context migration will not be performed, when receiving a user equipment context retrieval request message from the serving base station, the anchor base station will not send all user equipment contexts, but will instead feed back a user equipment context retrieval failure message to the serving base station to notify the serving base station that it has failed to obtain all user equipment contexts.

[0165] S408, the serving base station sends downlink data / signaling to the user equipment in MT-SDT mode.

[0166] In other embodiments, the anchor base station responds to the user equipment context retrieval request message and sends a user equipment context retrieval failure message and encrypted downlink data / signaling (Encrypted Downlink Data or Signaling) to the serving base station in MT-SDT mode. The serving base station decrypts the encrypted downlink data / signaling (Encrypted Downlink Data or Signaling) to obtain downlink data / signaling (Downlink Data or Signaling), and sends the downlink data / signaling to the user equipment in MT-SDT mode.

[0167] Among them, the anchor base station can encrypt the downlink data / signaling (Downlink Data or Signaling) from the core network through the encryption algorithm to obtain the encrypted downlink data / signaling (Encrypted Downlink Data or Signaling). The serving base station can decrypt the encrypted downlink data / signaling (Encrypted Downlink Data or Signaling) using the key corresponding to the encryption algorithm to obtain the downlink data / signaling (Downlink Data or Signaling) sent by the core network.

[0168] In some embodiments, after obtaining the downlink data or signaling (Downlink Data or Signaling) of this time, the serving base station performs path switching with the core network to switch the downlink to the serving base station.

[0169] In some other embodiments, the anchor base station may migrate a partial user equipment context (Partial UE Context) within the effective area (RNA) of the radio access network, and transmit downlink data / signaling to the serving base station.

[0170] It can be understood that in this embodiment, a UE in an RRC inactive state moves within a radio access network notification area (RNA). When the UE is called, that is, there is downlink data / signaling that needs to be transmitted to the UE, the anchor base station first receives the downlink data / signaling from the core network, triggering the transmission of small data packets in the downlink, that is, transmitting the downlink data / signaling in MT-SDT mode. Then, the anchor base station determines whether to perform user equipment context (UE Context) migration. When it is determined that the user equipment context migration is not to be performed, if the anchor base station receives a Retrieve UE Context Request message from the serving base station, the downlink data / signaling is sent to the serving base station in MT-SDT mode. The serving base station sends downlink data / signaling to the user equipment in MT-SDT mode. In this way, the downlink data / signaling from the core network is transmitted in MT-SDT mode. In the scenario of mobile called, the anchor base station can send downlink data / signaling to the serving base station during the period when the UE is in the RRC inactive state, and then forward the downlink data / signaling to the UE through the serving base station, without the need for the UE to switch from the RRC inactive state to the RRC connected state. In this way, the number of signaling between the interfaces of the serving base station and the anchor base station can be reduced, and the signaling overhead caused by the state migration of the UE can be reduced, thereby reducing service latency.

[0171] The data transmission method provided by the present application is described in detail below through specific embodiments.

[0172] Example 1

[0173] Figure 5 This is a schematic diagram of information interaction of a data transmission method in the scenario where the anchor base station performs user equipment context migration. Figure 5 , the data transmission method may include the following steps:

[0174] S501, the anchor base station obtains downlink data / signaling (Downlink Signaling or Data) from the core network.

[0175] The downlink data / signaling carries the first configuration information.

[0176] It can be understood that when the UE is called, the downlink data / signaling sent by the core network needs to be transmitted to the UE. At this time, the anchor base station first obtains the downlink data / signaling sent by the core network.

[0177] S502: The anchor base station determines whether to perform user equipment context (UE Context) migration.

[0178] It should be noted that Figure 5The illustrated embodiment is described by taking user equipment context migration as an example.

[0179] In this embodiment, when receiving downlink data / signaling from the core network, the anchor base station can determine whether to perform user equipment context migration according to the first configuration information carried by the downlink data / signaling. Compared with the solution of performing user equipment context migration by default, this embodiment can be determined according to actual needs, which can save signaling resources and avoid wasting signaling resources by performing user equipment context migration when it is not necessary.

[0180] S503: The anchor base station sends a paging message to the serving base station, where the paging message carries first indication information.

[0181] The first indication information is used to indicate triggering of MT-SDT. The first indication information may include a cause value (eg, MT-SDT or SDT), a bearer type, and priority information.

[0182] For example, the cause value MT-SDT is used to indicate that downlink data or signaling is transmitted in MT-SDT mode, and the cause value SDT is used to indicate that downlink data or signaling is transmitted in SDT mode.

[0183] The bearer type is used to indicate which type of radio bearer (Radio Bearer, RB) the downlink data or signaling (Downlink Data or Signaling) belongs to, for example, which type of data radio bearer (Data Radio Bearer, DRB) it belongs to (for example, DRB1 or DRB2), or which type of signaling radio bearer (Signaling Radio Bearer, SRB) it belongs to (for example, SRB1 or SRB2).

[0184] The priority information is used to indicate the priority of a paging message. For example, it may indicate that the paging message has a high priority.

[0185] S504, the serving base station sends a paging message to the user equipment.

[0186] S505, after receiving the paging message, the user equipment sends an RRC resume request (RRC Resume Request) message to the serving base station, where the RRC resume request message carries the first indication information.

[0187] It can be understood that the RRC recovery request message is used to request the establishment of an MT-SDT session, and the MT-SDT session can be used for data transmission of MT-SDT services. After the UE is successfully paged, the UE triggers MT-SDT according to the first indication information carried in the paging message to request the transmission of downlink data / signaling via MT-SDT.

[0188] In this embodiment, the purpose of the RRC recovery request message carrying the first indication information is to request transmission of downlink data / signaling in MT-SDT mode.

[0189] S506, after receiving the RRC recovery request message, the serving base station sends a retrieve UE context request message to the anchor base station, where the retrieve UE context request message carries the first indication information and a downlink address.

[0190] The downlink address may include a GPRS Tunnelling Protocol (GTP) address and a port number.

[0191] It can be understood that the retrieve user equipment context request message is used to request to obtain the user equipment context from the anchor base station to manage the RRC state of the UE.

[0192] S507, after receiving the retrieve UE context request message, the anchor base station sends a retrieve UE context response (Retrieve UE Context Response) message and downlink data / signaling (Downlink Data or Signaling) to the serving base station.

[0193] The retrieve user equipment context response message carries the user equipment context, and may also carry at least one of the following information: the size and frequency of data packets allowed to be transmitted, and auxiliary information.

[0194] It can be understood that after receiving the retrieval user equipment context request message, the anchor base station triggers MT-SDT according to the first indication information, and transmits the retrieval user equipment context response message and downlink data / signaling to the serving base station in MT-SDT mode via the downlink address.

[0195] S508, the serving base station sends a path switch request (Path Switch Request) message to the core network to switch the downlink to the serving base station.

[0196] S509, the core network sends a path switch response (Path Switch Response) message to the serving base station to notify the serving base station that the downlink has been switched.

[0197] S510, the serving base station sends downlink data / signaling to the user equipment.

[0198] The serving base station can schedule downlink data / signaling according to the base station implementation algorithm, the auxiliary information or the first indication information in the auxiliary information. The base station implementation algorithm includes various algorithms for implementing base station functions, such as algorithms for implementing load balancing, positioning and data encryption / decryption.

[0199] S511, the core network sends subsequent downlink data / signaling (Subsequent Downlink Data or Signaling) to the user equipment.

[0200] It can be understood that after the path switching is completed, subsequent downlink data / signaling from the core network can be directly forwarded by the serving base station to the user equipment.

[0201] S512, the serving base station sends a user equipment context release (UE Context Release) message to the anchor base station to instruct the anchor base station to release its cached user equipment context (UE Context).

[0202] S513, the serving base station sends an RRC Release message to the user equipment to instruct the user equipment to enter an RRC inactive state or an idle state.

[0203] It can be understood that the RRC release message is used to indicate the termination of the MT-SDT session. The serving base station can indicate the termination of the MT-SDT session based on certain judgment conditions. For example, when the duration of the MT-SDT service ends, or the data transmission of the MT-SDT service is completed, the serving base station can indicate the termination of the MT-SDT session.

[0204] In this embodiment, in a mobile called (MT) scenario, when the anchor base station determines to perform user equipment context (UEContext) migration, if the UE is called, that is, the anchor base station receives downlink data / signaling (Downlink Data or Signaling) from the core network, a paging (Paging) message carrying the first indication information is triggered in the notification area of ​​the wireless access network. After the user equipment receives the paging message, an RRC resume request (RRC Resume Request) message is triggered to instruct the serving base station to resume the suspended bearer. After the serving base station receives the RRC resume request message, a retrieve user equipment context request (Retrieve UE Context Request) message is triggered. After the anchor base station receives the restore user equipment context request message, a retrieve user equipment context response (Retrieve UE Context Response) message is triggered, and downlink data / signaling is sent to the serving base station. After the serving base station performs path switching between the core network and the core network, the core network can directly schedule subsequent downlink data / signaling (Subsequent Downlink Data or Signaling) to the user equipment. The serving base station triggers a UE Context Release message to the anchor base station to instruct the anchor base station to release its cached UE Context; and sends an RRC Release message to the user equipment to instruct the user equipment to enter an RRC inactive state or an idle state.

[0205] Example 2

[0206] The difference between Embodiment 2 and Embodiment 1 is that after step S512 in Embodiment 1, the serving base station triggers an RRC resume (RRC Resume) message to instruct the user equipment to enter the RRC connected state.

[0207] Figure 6 This is a schematic diagram of information interaction of another data transmission method in the scenario where the anchor base station performs user equipment context migration. Figure 6 , the data transmission method may include the following steps:

[0208] S601, the anchor base station obtains downlink data / signaling (Downlink Signaling or Data) from the core network.

[0209] S602: The anchor base station determines whether to perform user equipment context (UE Context) migration.

[0210] S603: The anchor base station sends a paging message to the serving base station, where the paging message carries first indication information.

[0211] S604, the serving base station sends a paging message to the user equipment.

[0212] S605, after receiving the paging message, the user equipment sends an RRC resume request (RRC Resume Request) message to the serving base station, where the RRC resume request message carries the first indication information.

[0213] S606, after receiving the RRC recovery request message, the serving base station sends a retrieve UE context request message to the anchor base station, where the retrieve UE context request message carries the first indication information and a downlink address.

[0214] S607, after receiving the retrieve UE context request message, the anchor base station sends a retrieve UE context response (Retrieve UE Context Response) message and downlink data / signaling (Downlink Data or Signaling) to the serving base station.

[0215] S608, the serving base station sends a path switch request (Path Switch Request) message to the core network to switch the downlink to the serving base station.

[0216] S609, the core network sends a path switch response (Path Switch Response) message to the serving base station to notify the serving base station that the downlink has been switched.

[0217] S610, the serving base station sends downlink data or signaling to the user equipment.

[0218] S611, the core network sends subsequent downlink data / signaling (Subsequent Downlink Data or Signaling) to the user equipment.

[0219] S612, the serving base station sends a user equipment context release (UE Context Release) message to the anchor base station to instruct the anchor base station to release its cached user equipment context (UE Context).

[0220] It can be understood that the above steps S601 to S612 are the same as steps S501 to S512 in Example 1, and will not be repeated here.

[0221] S613: The serving base station determines whether to instruct the user equipment to switch to the RRC connected state.

[0222] It should be noted that Figure 6 The illustrated embodiment is described by taking the example of instructing the user equipment to switch to the RRC connected state.

[0223] When at least one of the following conditions is met, the serving base station determines to instruct the user equipment to switch to the RRC connected state.

[0224] Condition 1: Update security context information: When downlink data / signaling needs to be encrypted and integrity protected for security reasons, the serving base station updates the security context information.

[0225] Condition 2: Acquire downlink data of a non-MT-SDT bearer, wherein a non-MT-SDT bearer refers to a bearer that does not support the MT-SDT function.

[0226] Condition 3: The size of the data packet is greater than the first preset threshold. The size of the data packet may be the size of a single data packet or the size of the total amount of data. The size of the total amount of data refers to the total amount of data allowed to be transmitted during the mobile terminated small data packet transmission (MT-SDT). The size of the total amount of data may be the size of the downlink and / or uplink data.

[0227] Condition 4: The number of data packets is greater than a second preset threshold, wherein the number of data packets refers to the number of downlink data packets sent and / or uplink data packets received during a small data packet transmission (SDT) period.

[0228] It can be understood that the value of the first preset threshold / the second preset threshold is related to factors such as transmission bandwidth, transmission rate and transmission quality, and the base station can set the first preset threshold / the second preset threshold according to the data transmission situation.

[0229] S614, the serving base station sends an RRC resume (RRC Resume) message to the user equipment to instruct the user equipment to enter the RRC connected state.

[0230] S615, after entering the RRC connected state, the user equipment sends an RRC resume complete message to the serving base station.

[0231] The RRC recovery completion message is used to notify the serving base station that the user equipment has entered the RRC connected state.

[0232] It can be understood that in this embodiment, in the mobile called (MT) scenario, the anchor base station determines to perform user equipment context (UE Context) migration, and after the serving base station sends a user equipment context release (UE Context Release) message to the anchor base station, it determines whether to instruct the user equipment to switch to the RRC connected state. When it is determined to instruct the user equipment to switch to the RRC connected state, the serving base station triggers an RRC resume (RRC Resume) message to instruct the user equipment to enter the RRC connected state. When the user equipment enters the RRC connected state, an RRC resume complete (RRC Resume Complete) message is triggered. Before switching to the RRC connected state, the user equipment can receive downlink data / signaling (Downlink Data or Signaling) during the RRC inactive state.

[0233] Example 3

[0234] The difference between Embodiment 3 and Embodiment 1 is that after step S507 in Embodiment 1, the serving base station triggers an RRC Release message to instruct the user equipment to enter an RRC inactive state or an idle state.

[0235] Figure 7 It is an information interaction diagram of another data transmission method in the scenario where the anchor base station performs user equipment context migration.

[0236] See also Figure 7 , the data transmission method may include the following steps:

[0237] S701, the anchor base station obtains downlink data / signaling (Downlink Signaling or Data) from the core network.

[0238] S702: The anchor base station determines whether to perform user equipment context (UE Context) migration.

[0239] S703: The anchor base station sends a paging message to the serving base station, where the paging message carries first indication information.

[0240] S704, the serving base station sends a paging message to the user equipment.

[0241] S705, after receiving the paging message, the user equipment sends an RRC resume request (RRC Resume Request) message to the serving base station, where the RRC resume request message carries the first indication information.

[0242] S706, after receiving the RRC recovery request message, the serving base station sends a retrieve UE context request message to the anchor base station, where the retrieve UE context request message carries the first indication information and a downlink address.

[0243] S707, after receiving the retrieve UE context request message, the anchor base station sends a retrieve UE context response (Retrieve UE Context Response) message and downlink data / signaling (Downlink Data or Signaling) to the serving base station.

[0244] It can be understood that the above steps S701 to S707 are the same as steps S501 to S507 in Example 1, and will not be repeated here.

[0245] S708: The serving base station determines whether to instruct the user equipment to enter an RRC inactive state or an idle state.

[0246] It should be noted that Figure 7 The illustrated embodiment is described by taking the example of instructing the user equipment to enter the RRC inactive state or the idle state.

[0247] When at least one of the following conditions is met, the serving base station determines to instruct the user equipment to enter an RRC inactive state or an idle state.

[0248] Condition 1: Execute the base station implementation algorithm and configure the user equipment to enter the RRC inactive state or idle state based on the algorithm implementation.

[0249] Condition 2: Acquire auxiliary information, where the auxiliary information is used to perform SDT indication on the data to be transmitted, so as to instruct the serving base station to perform SDT.

[0250] Condition three: obtaining first indication information, where the first indication information is used to instruct the serving base station to trigger MT-SDT.

[0251] S709, the serving base station sends an RRC Release message to the user equipment to instruct the user equipment to enter an RRC inactive state or an idle state, and sends downlink data / signaling to the user equipment.

[0252] In this embodiment, the serving base station transmits downlink data / signaling together when triggering the RRC release message, which can reduce the number of signaling between the serving base station and the user equipment, thereby reducing the MT-SDT service delay.

[0253] S710, the serving base station sends a path switch request (Path Switch Request) message to the core network to switch the downlink to the serving base station.

[0254] S711, the core network sends a path switch response (Path Switch Response) message to the serving base station to notify the serving base station that the downlink switching has been completed.

[0255] It can be understood that steps S710 to S711 are the same as steps S508 to S509 in Example 1, and are not described in detail here.

[0256] S712, the serving base station sends a user equipment context release (UE Context Release) message to the anchor base station to instruct the anchor base station to release its cached user equipment context (UE Context).

[0257] It can be understood that in this embodiment, in the mobile called (MT) scenario, the anchor base station determines to perform user equipment context (UE Context) migration. After the anchor base station sends a retrieve user equipment context response (Retrieve UE Context Response) message and downlink data / signaling (Downlink Data or Signaling) to the serving base station, the serving base station determines whether to instruct the user equipment to enter the RRC inactive state or idle state. When it is determined to instruct the user equipment to enter the RRC inactive state or idle state, the serving base station triggers an RRC release (RRC Release) message and sends downlink data / signaling (Downlink Data or Signaling) to the user equipment. After the serving base station performs a path switch between the core network, it triggers a user equipment context release (UE Context Release) message to instruct the anchor base station to release its cached user equipment context (UE Context).

[0258] Example 4

[0259] The difference between Embodiment 4 and Embodiment 1 is that after step S507 in Embodiment 1, the serving base station triggers an RRC resume (RRC Resume) message to instruct the user equipment to enter the RRC connected state.

[0260] Figure 8 It is an information interaction diagram of another data transmission method in the scenario where the anchor base station performs user equipment context migration.

[0261] See also Figure 8 , the data transmission method may include the following steps:

[0262] S801, the anchor base station obtains downlink data / signaling (Downlink Signaling or Data) from the core network.

[0263] S802: The anchor base station determines whether to perform user equipment context (UE Context) migration.

[0264] S803, the anchor base station sends a paging message to the serving base station, where the paging message carries first indication information.

[0265] S804, the serving base station sends a paging message to the user equipment.

[0266] S805, after receiving the paging message, the user equipment sends an RRC resume request (RRC Resume Request) message to the serving base station, where the RRC resume request message carries the first indication information.

[0267] S806, after receiving the RRC recovery request message, the serving base station sends a retrieve UE context request message to the anchor base station, where the retrieve UE context request message carries the first indication information and a downlink address.

[0268] S807, after receiving the retrieve UE context request message, the anchor base station sends a retrieve UE context response (Retrieve UE Context Response) message and downlink data / signaling (Downlink Data or Signaling) to the serving base station.

[0269] It can be understood that the above steps S801 to S807 are the same as steps S501 to S507 in Example 1, and will not be repeated here.

[0270] S808: The serving base station determines whether to instruct the user equipment to switch to the RRC connected state.

[0271] It should be noted that Figure 8 The illustrated embodiment is described by taking the example of instructing the user equipment to switch to the RRC connected state.

[0272] It can be understood that step S808 is the same as step S613 in embodiment 2, and will not be described in detail here.

[0273] S809, the serving base station sends an RRC resume (RRC Resume) message to the user equipment to instruct the user equipment to enter the RRC connection state, and sends downlink data / signaling (Downlink Data or Signaling) to the user equipment.

[0274] In this embodiment, the serving base station transmits downlink data / signaling together when triggering the RRC recovery message, which can reduce the number of signaling between the serving base station and the user equipment, thereby reducing the MT-SDT service delay.

[0275] S810, after entering the RRC connected state, the user equipment sends an RRC resume complete message to the serving base station.

[0276] The RRC recovery completion message is used to notify the serving base station that the user equipment has entered the RRC connected state.

[0277] It can be understood that in other embodiments, the RRC recovery completion message may not be sent.

[0278] S811, the serving base station sends a path switch request (Path Switch Request) message to the core network to switch the downlink to the serving base station.

[0279] S812, the core network sends a path switch response (Path Switch Response) message to the serving base station to notify the serving base station that the downlink has been switched.

[0280] It can be understood that the above steps S811 to S812 are the same as steps S508 to S509 in Example 1, and will not be repeated here.

[0281] S813, the serving base station sends a user equipment context release (UE Context Release) message to the anchor base station to instruct the anchor base station to release its cached user equipment context (UE Context).

[0282] It can be understood that in this embodiment, in the mobile called (MT) scenario, the anchor base station determines to perform user equipment context (UE Context) migration. After the anchor base station sends a Retrieve UE Context Response message and downlink data / signaling (Downlink Data or Signaling) to the serving base station, the serving base station determines whether to instruct the user equipment to switch to the RRC connected state. When it is determined to instruct the user equipment to switch to the RRC connected state, the serving base station triggers an RRC Resume (RRC Resume) message to instruct the user equipment to enter the RRC connected state and sends downlink data / signaling (Downlink Data or Signaling) to the user equipment. After the serving base station performs a path switch between the core network, it triggers a user equipment context release (UE Context Release) message to instruct the anchor base station to release its cached user equipment context (UE Context).

[0283] Example 5

[0284] The difference between Example 5 and Example 1 is that when the anchor base station determines to perform user equipment context (UEContext) migration, the anchor base station triggers a paging message and sends the user equipment context (UE Context) and downlink data / signaling (Downlink Data or Signaling) to the serving base station.

[0285] Fig. 9 It is an information interaction diagram of another data transmission method in the scenario where the anchor base station performs user equipment context migration.

[0286] See also Fig. 9 , the data transmission method may include the following steps:

[0287] S901, the anchor base station obtains downlink data / signaling (Downlink Signaling or Data) from the core network.

[0288] S902: The anchor base station determines whether to perform user equipment context (UE Context) migration.

[0289] It can be understood that the above steps S901 to S902 are the same as steps S601 to S602 in Example 1, and will not be repeated here.

[0290] S903, the anchor base station sends a paging message, a user equipment context (UE Context) and downlink data / signaling (Downlink Data or Signaling) to the serving base station, and the paging message carries the first indication information.

[0291] The address at which the serving base station receives downlink data / signaling is a default configuration address, or an address negotiated between the serving base station and the anchor base station when the Xn interface is established.

[0292] In this embodiment, the anchor base station transmits the user equipment context and downlink data / signaling together when triggering the paging message, which can reduce the number of signaling between the anchor base station and the serving base station, thereby reducing the MT-SDT service delay.

[0293] S904, the serving base station sends a paging message to the user equipment.

[0294] S905, after receiving the paging message, the user equipment sends an RRC resume request (RRC Resume Request) message to the serving base station, where the RRC resume request message carries the first indication information.

[0295] The RRC recovery request message is used to request the establishment of an MT-SDT session, and the MT-SDT session is used to transmit downlink data / signaling of the MT-SDT service.

[0296] S906, the serving base station sends downlink data / signaling to the user equipment.

[0297] It can be understood that after establishing the MT-SDT session, the serving base station transmits downlink data / signaling in the MT-SDT manner.

[0298] S907, the serving base station sends a path switch request (Path Switch Request) message to the core network to switch the downlink to the serving base station.

[0299] S908, the core network sends a path switch response (Path Switch Response) message to the serving base station to notify the serving base station that the downlink has been switched.

[0300] It can be understood that the above steps S907 to S908 are the same as steps S508 to S509 in Example 1, and will not be repeated here.

[0301] S909, the core network sends subsequent downlink data / signaling (Subsequent Downlink Data or Signaling) to the user equipment.

[0302] It can be understood that after the path switching is completed, subsequent downlink data / signaling from the core network can be directly forwarded by the serving base station to the user equipment.

[0303] S910, the serving base station sends a user equipment context release (UE Context Release) message to the anchor base station to instruct the anchor base station to release the cached user equipment context (UE Context) thereof.

[0304] S911, the serving base station sends an RRC Release message to the user equipment to instruct the user equipment to enter an RRC inactive state or an idle state.

[0305] The RRC release message is used to indicate the termination of the MT-SDT session.

[0306] It can be understood that in this embodiment, in the mobile called (MT) scenario, when the anchor base station determines to perform user equipment context migration, the anchor base station sends a paging (Paging) message, a user equipment context (UE Context) and downlink data / signaling (Downlink Data or Signaling) to the serving base station. After the user equipment receives the paging message, it triggers an RRC resume request (RRC Resume Request) message to instruct the serving base station to resume the suspended bearer. After receiving the RRC resume request message, the serving base station sends downlink data / signaling (Downlink Data or Signaling) to the user equipment. After the serving base station performs path switching between the serving base station and the core network, the core network can directly schedule subsequent downlink data / signaling (Subsequent Downlink Data or Signaling) to the user equipment. The serving base station triggers a user equipment context release (UE Context Release) message to the anchor base station to instruct the anchor base station to release its cached user equipment context (UE Context); and sends an RRC release (RRC Release) message to the user equipment to instruct the user equipment to enter the RRC inactive state or idle state.

[0307] Example 6

[0308] The difference between Example 6 and Example 5 is that after step S905 in Example 5, the serving base station triggers an RRC resume (RRC Resume) message and sends downlink data / signaling (Downlink Data or Signaling) to the user equipment.

[0309] Fig.10It is an information interaction diagram of another data transmission method in the scenario where the anchor base station performs user equipment context migration.

[0310] See also Fig.10 , the data transmission method may include the following steps:

[0311] S1001, the anchor base station obtains downlink data / signaling (Downlink Signaling or Data) from the core network.

[0312] S1002: The anchor base station determines whether to perform user equipment context (UE Context) migration.

[0313] S1003, the anchor base station sends a paging message, a user equipment context (UE Context) and downlink data / signaling (Downlink Data or Signaling) to the serving base station, and the paging message carries the first indication information.

[0314] S1004, the serving base station sends a paging message to the user equipment.

[0315] S1005, after receiving the paging message, the user equipment sends an RRC resume request (RRC Resume Request) message to the serving base station, where the RRC resume request message carries the first indication information.

[0316] It can be understood that the above steps S1001 to S1005 are the same as steps S901 to S905 in Example 5, and will not be repeated here.

[0317] S1006: The serving base station determines whether to instruct the user equipment to switch to the RRC connected state.

[0318] It should be noted that Fig.10 The illustrated embodiment is described by taking the example of instructing the user equipment to switch to the RRC connected state.

[0319] It can be understood that the specific implementation of step S1006 is the same as step S613 in Example 2, and will not be repeated here.

[0320] S1007, the serving base station sends an RRC resume (RRC Resume) message to the user equipment to instruct the user equipment to enter the RRC connection state, and sends downlink data / signaling (Downlink Data or Signaling) to the user equipment.

[0321] In this embodiment, the serving base station transmits downlink data / signaling together when triggering the RRC recovery message, which can reduce the number of signaling between the serving base station and the user equipment, thereby reducing the MT-SDT service delay.

[0322] S1008, after entering the RRC connected state, the user equipment sends an RRC resume complete (RRC Resume Complete) message to the serving base station.

[0323] S1009, the serving base station sends a path switch request (Path Switch Request) message to the core network to switch the downlink to the serving base station.

[0324] S1010, the core network sends a path switch response (Path Switch Response) message to the serving base station to notify the serving base station that the downlink has been switched.

[0325] It can be understood that the above steps S1009 to S1010 are the same as steps S907 to S908 in Example 5, and will not be repeated here.

[0326] S1011, the serving base station sends a user equipment context release (UE Context Release) message to the anchor base station to instruct the anchor base station to release its cached user equipment context (UE Context).

[0327] It can be understood that in this embodiment, in the mobile called (MT) scenario, the anchor base station determines to perform user equipment context (UE Context) migration, and when the user equipment triggers the RRC resume request (RRC Resume Request) message, the serving base station determines whether to instruct the user equipment to switch to the RRC connected state. When it is determined to instruct the user equipment to switch to the RRC connected state, the serving base station sends an RRC resume (RRC Resume) message to the user equipment to instruct the user equipment to enter the RRC connected state, and sends downlink data / signaling (Downlink Data or Signaling) to the user equipment. When the user equipment enters the RRC connected state, the RRC resume complete (RRC Resume Complete) message is triggered. After the serving base station performs a path switch between the core network, the user equipment context release (UE Context Release) message is triggered to instruct the anchor base station to release its cached user equipment context (UE Context). Before the user equipment enters the RRC connected state, it can receive downlink data / signaling (Downlink Data or Signaling) during the RRC inactive state.

[0328] Example 7

[0329] Fig.11 It is an information interaction diagram of a data transmission method in a scenario where an anchor base station does not perform user equipment context migration.

[0330] See also Fig.11 , the data transmission method may include the following steps:

[0331] S1101, the anchor base station obtains downlink data / signaling (Downlink Signaling or Data) from the core network.

[0332] S1102: The anchor base station determines whether to perform user equipment context (UE Context) migration.

[0333] It should be noted that Fig.11 The illustrated embodiment is described by taking the case where no user equipment context migration is performed as an example.

[0334] S1103, the anchor base station sends a user equipment partial context setup request (UE Partial Context SetupRequest) message to the serving base station.

[0335] The user equipment partial context setting request message is used to request the transmission of a partial user equipment context. The user equipment partial context setting request message carries second configuration information, and the second configuration information is used to configure a data transmission mode (such as MT-SDT or SDT, etc.) in a scenario where user equipment context migration is not performed.

[0336] It should be noted that the anchor base station does not perform user equipment context migration, which means not migrating all contexts. For some user equipment contexts required for information transmission between the serving base station and the user equipment, the anchor base station still needs to transmit the part of the user equipment context to the serving base station.

[0337] The second configuration information may include a paging message, a partial UE context, a protocol data unit (PDU) of the packet data convergence protocol (PDCP) layer of downlink data / signaling, and an address of the anchor base station for receiving uplink data (eg, a GTP tunnel address and port number).

[0338] The paging message carries first indication information, and the first indication information is used to indicate triggering of MT-SDT.

[0339] The partial user equipment context (Partial UE Context) may include a context (Context) of a radio link control (Radio Link Control, RLC) layer and a context (Context) of a media access control (Media Access Control, MAC) layer.

[0340] The protocol data unit (PDCP PDU) of the packet data convergence protocol layer of downlink data / signaling stores downlink data / signaling. The protocol data unit (PDCP PDU) of the packet data convergence protocol layer includes data PDU and control PDU. The data PDU is used to transmit downlink data of the user plane and the control plane and generate a digital signature for integrity protection. The control PDU is used to transmit the status report of the PDCP layer and decompress the feedback message.

[0341] S1104, the serving base station sends a paging message to the user equipment, where the paging message carries first indication information.

[0342] S1105, after receiving the paging message, the user equipment sends an RRC resume request (RRC Resume Request) message to the serving base station, where the RRC resume request message carries the first indication information.

[0343] In this embodiment, the purpose of the RRC recovery request message carrying the first indication information is to request to establish an MT-SDT session, so as to transmit downlink data / signaling in MT-SDT mode.

[0344] S1106, after receiving the RRC recovery request message, the serving base station sends downlink data / signaling (Downlink Data or Signaling) to the user equipment.

[0345] It is understood that in other embodiments, before executing step S1106, the serving base station may send a path switching request message to the core network to switch the downlink to the serving base station. After receiving the path switching response message from the core network, the serving base station sends downlink data / signaling to the user equipment.

[0346] S1107, the serving base station sends a user equipment partial context setup response (UE Partial Context SetupResponse) message to the anchor base station.

[0347] The user equipment partial context setting response message is used to notify the anchor base station that the partial user equipment context has been transmitted. The user equipment partial context setting response message may carry the address of the serving base station for receiving downlink data, such as the GTP address and port number.

[0348] S1108, after receiving the partial context setting response message of the user equipment, the anchor base station sends subsequent data / signaling to the user equipment.

[0349] It can be understood that after receiving the partial context setting response message of the user equipment, the anchor base station transmits subsequent data / signaling to the serving base station through the address of the serving base station receiving downlink data, and the serving base station then forwards the subsequent data / signaling to the user equipment.

[0350] S1109, the anchor base station sends an RRC Release message to the user equipment to instruct the user equipment to enter an RRC inactive state or an idle state.

[0351] It can be understood that after the subsequent data / signaling transmission is completed, the anchor base station transmits an RRC release message to the serving base station through the address of the serving base station receiving downlink data, and the serving base station then forwards the RRC release message to the user equipment, thereby terminating the MT-SDT session.

[0352] In this embodiment, in a mobile called (MT) scenario, when the anchor base station determines not to perform user equipment context (UE Context) migration, a user equipment partial context setup request (UE Partial Context Setup Request) message is triggered, and the user equipment partial context setup request message carries the second configuration information. After the serving base station receives the user equipment partial context setup request message, it sends a paging message in the second configuration information to the user equipment. After the user equipment receives the paging message, it sends an RRC resume request (RRC Resume Request) message to the serving base station to instruct the serving base station to resume the suspended bearer. After receiving the RRC resume request message, the serving base station sends downlink data / signaling (Downlink Data or Signaling) to the user equipment and triggers a user equipment partial context setup response (UE Partial Context Setup Response) message. Then, the anchor base station can directly send subsequent data / signaling (Subsequent Data or Signaling) to the user equipment, and can trigger an RRC release (RRC Release) message to instruct the user equipment to enter an RRC inactive state or an idle state.

[0353] Example 8

[0354] The difference between Example 8 and Example 7 is that when the anchor base station determines not to perform user equipment context (UEContext) migration, the anchor base station does not trigger a user equipment partial context setup request (UE Partial ContextSetup Request) message, but after receiving a retrieval user equipment context request (Retrieve UE Context Request) message from a serving base station, it triggers a retrieval user equipment context failure (Retrieve UEContext Failure) message and sends encrypted downlink data / signaling (Encrypted Downlink Data orSignaling) to the serving base station.

[0355] Fig.12 This is an information interaction diagram of another data transmission method in the scenario where the anchor base station does not perform user equipment context migration. Fig.12 , the data transmission method may include the following steps:

[0356] S1201, the anchor base station obtains downlink data / signaling (Downlink Signaling or Data) from the core network.

[0357] S1202: The anchor base station determines whether to perform user equipment context (UE Context) migration.

[0358] It should be noted that Fig.12 The illustrated embodiment is described by taking the case where no user equipment context migration is performed as an example.

[0359] S1203: The anchor base station sends a paging message to the serving base station, where the paging message carries first indication information.

[0360] The first indication information is used to indicate triggering of MT-SDT.

[0361] S1204: The serving base station sends a paging message to the user equipment.

[0362] S1205, after receiving the paging message, the user equipment sends an RRC resume request (RRC Resume Request) message to the serving base station, where the RRC resume request message carries the first indication information.

[0363] In this embodiment, the purpose of the RRC recovery request message carrying the first indication information is to request transmission of downlink data / signaling in MT-SDT mode.

[0364] S1206, after receiving the RRC recovery request message, the serving base station sends a retrieve UE context request message to the anchor base station, where the retrieve UE context request message carries the first indication information and a downlink address.

[0365] It can be understood that the retrieve user equipment context request message is used to request to obtain the user equipment context from the anchor base station to manage the RRC state of the UE.

[0366] S1207, the anchor base station sends a Retrieve UE Context Failure message and encrypted downlink data or signaling to the serving base station.

[0367] The user equipment context retrieval failure message is used to notify the serving base station that all user equipment contexts cannot be obtained. The user equipment context retrieval failure message may carry the address of the anchor base station for receiving uplink data, such as the GTP address and port number.

[0368] The anchor base station can encrypt the downlink data / signaling (Downlink Data or Signaling) from the core network through an encryption algorithm to obtain encrypted downlink data / signaling (Encrypted Downlink Data or Signaling).

[0369] It is understandable that in other embodiments, the anchor base station may not encrypt the downlink data / signaling and directly send the downlink data / signaling to the serving base station.

[0370] S1208, the serving base station decrypts the encrypted downlink data / signaling to obtain the downlink data / signaling, and sends the decrypted downlink data / signaling to the user equipment.

[0371] It can be understood that the serving base station can use the key corresponding to the encryption algorithm to decrypt the encrypted downlink data / signaling (Encrypted Downlink Data or Signaling) to obtain the downlink data / signaling (Downlink Data or Signaling) sent by the core network.

[0372] In other embodiments, before sending downlink data / signaling, the serving base station may send a path switching request message to the core network to switch the downlink to the serving base station. After receiving the path switching response message from the core network, the serving base station sends the downlink data / signaling to the user equipment.

[0373] S1209, the core network sends subsequent data / signaling (Subsequent Data or Signaling) to the user equipment.

[0374] It can be understood that after sending downlink data / signaling to the user equipment for the first time, the core network can forward subsequent data / signaling to the user equipment in sequence through the anchor base station and the serving base station.

[0375] In other embodiments, the core network may also directly forward subsequent data / signaling to the user equipment through the serving base station.

[0376] S1210, the anchor base station sends a user equipment context release (UE Context Release) message to the serving base station, where the user equipment context release message carries an RRC release (RRC Release) message.

[0377] It can be understood that after the MT-SDT service data transmission is completed, the anchor base station can instruct the serving base station to release part of its cached user equipment context and instruct to terminate the MT-SDT session. The serving base station does not need to continue to cache part of the user equipment context, which can save the storage space of the serving base station and improve the flexibility of resource scheduling. The MT-SDT service data includes all data sent by the core network during the mobile call (MT), including the downlink data / signaling transmitted for the first time in step S1208 and the subsequent data / signaling in step S1209.

[0378] The user equipment context release message is used to instruct the serving base station to release part of the user equipment context cached by it. The RRC release message is used to instruct the termination of the MT-SDT session.

[0379] In this embodiment, the anchor base station triggers the RRC release message when triggering the user equipment context release message, which can reduce the number of signaling between the anchor base station and the serving base station, thereby reducing the MT-SDT service delay.

[0380] S1211, after receiving the user equipment context release message, the serving base station sends an RRC Release message to the user equipment to instruct the user equipment to enter an RRC inactive state or an idle state.

[0381] In this embodiment, the serving base station first releases part of its cached user equipment context according to the user equipment context release message, and then instructs the user equipment to enter the RRC inactive state or idle state according to the RRC release message carried in the user equipment context release message, thereby terminating the MT-SDT session.

[0382] S1212, the serving base station sends a UE Context Release Complete message to the anchor base station to notify the anchor base station that the user equipment has entered an RRC inactive state or an idle state.

[0383] In other embodiments, the serving base station may not trigger a user equipment context release complete (UE Context Release Complete) message.

[0384] It can be understood that in this embodiment, in the mobile called (MT) scenario, when the anchor base station determines not to perform user equipment context (UE Context) migration, after the serving base station triggers the retrieval of user equipment context request (Retrieve UEContext Request) message, the anchor base station triggers the retrieval of user equipment context failure (Retrieve UE ContextFailure) message, and sends the encrypted downlink data / signaling (Encrypted Downlink Data or Signaling) to the serving base station. When the serving base station receives the encrypted downlink data / signaling, it decrypts the encrypted downlink data / signaling to obtain the downlink data / signaling (Downlink Data or Signaling), and sends the downlink data / signaling to the user equipment. Then, the core network sends subsequent data / signaling (Subsequent Data or Signaling) to the user equipment. The anchor base station triggers a user equipment context release (UE Context Release) message, and the user equipment context release message carries an RRC release (RRC Release) message. When the serving base station obtains the RRC release message from the user equipment context release message, it triggers the RRC release message to indicate that the user equipment enters the RRC inactive state or idle state. After triggering the RRC release message, the serving base station may trigger the UE Context Release Complete message to notify the anchor base station that the user equipment has entered the RRC inactive state or idle state.

[0385] Example 9

[0386] The difference between Example 9 and Example 8 is that after step S1206 in Example 8, the anchor base station triggers a Retrieve UE Context Failure message and sends encrypted downlink data / signaling to the serving base station. The Retrieve UE Context Failure message carries an RRC Release message.

[0387] Fig.13 This is an information interaction diagram of another data transmission method in the scenario where the anchor base station does not perform user equipment context migration. Fig.13 , the data transmission method may include the following steps:

[0388] S1301, the anchor base station obtains downlink data / signaling (Downlink Signaling or Data) from the core network.

[0389] S1302: The anchor base station determines whether to perform user equipment context (UE Context) migration.

[0390] It should be noted that Fig.13 The illustrated embodiment is described by taking the case where no user equipment context migration is performed as an example.

[0391] S1303: The serving base station sends a paging message to the user equipment, where the paging message carries first indication information.

[0392] S1304: The serving base station sends a paging message to the user equipment.

[0393] S1305, after receiving the paging message, the user equipment sends an RRC resume request (RRC Resume Request) message to the serving base station, where the RRC resume request message carries the first indication information.

[0394] S1306, after receiving the RRC recovery request message, the serving base station sends a retrieve UE context request message to the anchor base station, where the retrieve UE context request message carries the first indication information and a downlink address.

[0395] It can be understood that the above steps S1301 to S1306 are the same as steps S1201 to S1206 in Example 8, and will not be repeated here.

[0396] S1307, the anchor base station sends a Retrieve UE Context Failure message and encrypted downlink data / signaling to the serving base station, and the Retrieve UE Context Failure message carries an RRC Release message.

[0397] It can be understood that when notifying the serving base station that all user equipment contexts cannot be acquired, the anchor base station can also instruct to terminate the MT-SDT session.

[0398] The UE context retrieval failure message is used to notify the serving base station that all UE contexts cannot be obtained. The RRC release message is used to indicate the termination of the MT-SDT session.

[0399] In this embodiment, the anchor base station triggers an RRC release message when triggering the failure to retrieve the user equipment context, which can reduce the number of signaling between the anchor base station and the serving base station, thereby reducing the MT-SDT service delay.

[0400] S1308, the serving base station decrypts the encrypted downlink data / signaling to obtain the downlink data / signaling, and sends the downlink data / signaling to the user equipment.

[0401] It can be understood that step S1308 is the same as step S1208 in Example 8 and will not be described in detail here.

[0402] S1309, the serving base station sends an RRC Release message to the user equipment to instruct the user equipment to enter an RRC inactive state or an idle state.

[0403] In this embodiment, after transmitting downlink data / signaling to the user equipment, the serving base station instructs the user equipment to enter an RRC inactive state or an idle state according to the RRC release message, thereby terminating the MT-SDT session.

[0404] S1310, the serving base station sends a UE Context Release Complete message to the anchor base station to notify the anchor base station that the user equipment has entered an RRC inactive state or an idle state.

[0405] In other embodiments, the serving base station may not trigger the user equipment context release completion message.

[0406] It can be understood that in this embodiment, in the mobile called (MT) scenario, when the anchor base station determines not to perform user equipment context (UE Context) migration, after the serving base station triggers the retrieval user equipment context request (Retrieve UEContext Request) message, the anchor base station triggers the retrieval user equipment context failure (Retrieve UE ContextFailure) message, and sends the encrypted downlink data / signaling (Encrypted Downlink Data or Signaling) to the serving base station, and the retrieval user equipment context failure message carries the RRC release (RRC Release) message. When the serving base station receives the encrypted downlink data / signaling, it decrypts the encrypted downlink data / signaling to obtain the downlink data / signaling (Downlink Data or Signaling), and sends the downlink data / signaling to the user equipment. After the serving base station obtains the RRC release message from the retrieval user equipment context failure message, it triggers the RRC release (RRC Release) message to instruct the user equipment to enter the RRC inactive state or idle state. After triggering the RRC release message, the serving base station may trigger a UE context release complete (UE Context Release Complete) message to notify the anchor base station that the user equipment has entered the RRC inactive state or idle state.

[0407] It should be noted that in scenario two, the anchor base station and the service base station are the same base station. The "service base station" and "anchor base station" in all the method steps of the above embodiment of scenario one can be replaced with "network equipment" or "base station" to implement the data transmission method in scenario two.

[0408] It can be understood that the embodiments of the present application can also be used in other business scenarios, such as the Quality of Service (QoS) requirements of services such as Extended Reality (XR) and Ultra Reliable Low Latency Communication (URLLC). The network device can quickly restore the downlink connection and transmit the downlink data / signaling to the user device in a timely manner by notifying the user device to receive downlink data / signaling during the RRC inactive state.

[0409] Fig.14 It is a schematic diagram of the structure of a network device 100 according to an embodiment of the present application.

[0410] The network device 100 may be a serving base station, see Fig.14The network device 100 may include a first memory 110 and a first processor 120. The first memory 110 is used to store computer programs or instructions. The first processor 120 can call the computer programs or instructions stored in the first memory 110 to execute all method steps of the service base station side method embodiment in the embodiment of the present application.

[0411] Fig.15 It is a schematic diagram of the structure of a network device 200 according to an embodiment of the present application.

[0412] The network device 200 may be an anchor base station, see Fig.15 The network device 200 may include a second memory 210 and a second processor 220. The second memory 210 is used to store computer programs or instructions. The second processor 220 can call the computer program or instructions stored in the second memory 210 to execute all method steps of the anchor base station side method embodiment in the embodiment of the present application.

[0413] Fig.16 It is a structural diagram of a user equipment according to one embodiment of the present application.

[0414] In some embodiments, the structure of the user equipment (UE) may be as follows: Fig.16 As shown, the UE may include: a processor 1610, an external memory interface 1620, an internal memory 1621, a universal serial bus (USB) interface 1630, a charging management module 1640, a power management module 1641, a battery 1642, an antenna 1, an antenna 2, a mobile communication module 1650, a wireless communication module 1660, an audio module 1670, a speaker 1670A, a receiver 1670B, a microphone 1670C, an earphone interface 1670D, a sensor module 1680, a button 1690, a motor 1691, an indicator 1692, a camera 1693, a display screen 1694, and a subscriber identification module (SIM) card interface 1695, etc. The sensor module 1680 may include a pressure sensor 1680A, a gyroscope sensor 1680B, an air pressure sensor 1680C, a magnetic sensor 1680D, an acceleration sensor 1680E, a distance sensor 1680F, a proximity light sensor 1680G, a fingerprint sensor 1680H, a temperature sensor 1680J, a touch sensor 1680K, an ambient light sensor 1680L, a bone conduction sensor 1680M, and the like.

[0415] It is to be understood that the structure illustrated in this embodiment does not constitute a specific limitation on the UE. In other embodiments, the UE may include more or fewer components than shown in the figure, or combine certain components, or split certain components, or arrange the components differently. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0416] The processor 1610 may include one or more processing units, for example, the processor 1610 may include an application processor (AP), a modem, a graphics processing unit (GPU), an image signal processor (ISP), a controller, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural-network processing unit (NPU), etc. Different processing units may be independent devices or integrated into one or more processors.

[0417] The charging management module 1640 is used to receive charging input from a charger, where the charger can be a wireless charger or a wired charger.

[0418] The power management module 1641 is used to connect the battery 1642, the charging management module 1640 and the processor 1610. The power management module 1641 receives input from the battery 1642 and / or the charging management module 1640 to power the processor 1610, the internal memory 1671, the display screen 1694, the camera 1693, and the wireless communication module 1660.

[0419] The wireless communication function of the UE can be implemented through antenna 1, antenna 2, mobile communication module 1650, wireless communication module 1660, modem and baseband processor.

[0420] Antenna 1 and antenna 2 are used to transmit and receive electromagnetic wave signals. Each antenna in the UE can be used to cover a single or multiple communication frequency bands. Different antennas can also be reused to improve antenna utilization.

[0421] The mobile communication module 1650 can provide wireless communication solutions including 2G / 3G / 4G / 5G applied on the UE.

[0422] The wireless communication module 1660 can provide wireless communication solutions including wireless local area networks (WLAN) (such as wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), infrared (IR), etc., which are applied to the UE. The wireless communication module 1660 can be one or more devices integrating at least one communication processing module. The wireless communication module 1660 receives electromagnetic waves via antenna 2, modulates and filters the electromagnetic wave signals, and sends the processed signals to the processor 1610. The wireless communication module 1660 can also receive the signal to be sent from the processor 1610, modulate the frequency, amplify it, and convert it into electromagnetic waves for radiation through antenna 2.

[0423] In an embodiment of the present application, the wireless communication module 1660 may be used for the UE to send a request to a network node to restore an RRC connection, and to receive a response message from the network node.

[0424] The UE implements the display function through the GPU, the display screen 1694, and the application processor, etc. The GPU is a microprocessor for image processing, which is connected to the display screen 1694 and the application processor.

[0425] The display screen 1694 is used to display images, videos, etc. A series of graphical user interfaces (GUIs) may be displayed on the display screen 1694 of the UE.

[0426] The UE may implement a shooting function through an ISP, a camera 1693, a video codec, a GPU, a display screen 1694, and an application processor.

[0427] Camera 1693 is used to capture still images or videos.

[0428] The external memory interface 1620 may be used to connect an external memory card, such as a Micro SD card, to expand the storage capacity of the UE.

[0429] The internal memory 1621 may be used to store computer executable program codes, where the executable program codes include instructions. The processor 1610 executes various functional applications and data processing of the UE by running the instructions stored in the internal memory 1621 .

[0430] The UE may implement audio functions through an audio module 1670, a speaker 1670A, a receiver 1670B, a microphone 1670C, an earphone interface 1670D, and an application processor, etc. For example, music playback, recording, etc. The UE may also include a pressure sensor 1680A, an air pressure sensor 1680C, a gyroscope sensor 1680B, a magnetic sensor 1680D, an acceleration sensor 1680E, a distance sensor 1680F, a proximity light sensor 1680G, an ambient light sensor 1680L, a fingerprint sensor 1680H, a temperature sensor 1680J, a touch sensor 1680K, a bone conduction sensor 1680M, a button 1690, a motor 1691, an indicator 1692, etc.

[0431] The SIM card interface 1695 is used to connect a SIM card. The SIM card can be connected to or disconnected from the UE by inserting the SIM card interface 1695 or removing the SIM card from the SIM card interface 1695. The UE can support 1 or N SIM card interfaces, where N is a positive integer greater than 1. The SIM card interface 1695 can support Nano SIM cards, Micro SIM cards, SIM cards, and the like. Multiple cards can be inserted into the same SIM card interface 1695 at the same time. The SIM card interface 1695 is also compatible with external memory cards. The UE interacts with the network through the SIM card to implement functions such as calls and data communications.

[0432] In addition, an operating system, such as Hongmeng operating system, IOS operating system, Android operating system, Windows operating system, etc., is running on the above components. Applications can be installed and run on the operating system. In other embodiments, there may be multiple operating systems running in the UE.

[0433] It should be understood that Fig.16 The hardware modules included in the UE shown are only illustrative descriptions and do not limit the specific structure of the UE. In fact, the UE provided in the embodiment of the present application may also include other hardware modules that have an interactive relationship with the hardware modules illustrated in the figure, which are not specifically limited here. For example, the UE may also include a flashlight, a micro-projection device, etc. For another example, if the UE is a PC, then the UE may also include components such as a keyboard and a mouse.

[0434] Understandably, Fig.16 The user equipment shown can implement all method steps of the user equipment side method embodiment in the embodiment of the present application.

[0435] The embodiment of the present application also provides a computer-readable storage medium for storing a computer program or instruction. When the computer program or instruction is executed by a processor, the data transmission method of the embodiment of the present application is implemented. The same method steps and beneficial effects are not repeated here.

[0436] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present application.

Claims

1. A data transmission method, applied to an anchor base station, characterized in that: The method comprises: Acquire downlink data or signaling for a user equipment from a core network, wherein the user equipment is in a radio resource control RRC inactive state, the downlink data or signaling carries first configuration information, and the first configuration information is used to determine whether to perform user equipment context migration; the first configuration information includes auxiliary information, and the auxiliary information is used to perform a small data packet transmission SDT indication for data to be transmitted, and the auxiliary information includes at least one of the following information: subscription data, capabilities, data transmission statistics, data or signaling service characteristics and first indication information related to the SDT of the user equipment; the first indication information is used to indicate triggering mobile terminated small data packet transmission MT-SDT; Determining whether to perform the user equipment context migration according to the first configuration information; If it is determined to perform the user equipment context migration, the user equipment context is migrated to the serving base station, and the downlink data or signaling is sent to the serving base station.

2. The data transmission method according to claim 1, characterized in that: The sending the downlink data or signaling to the serving base station includes: The downlink data or signaling is sent to the serving base station in a mobile terminated small data packet transmission (MT-SDT) mode.

3. The data transmission method according to claim 1 or 2, characterized in that: The first configuration information also includes at least one of the following information: radio bearer and data packet size.

4. The data transmission method according to claim 1 or 2, characterized in that: Before migrating the user equipment context to the serving base station, the method further includes: receiving a user equipment context retrieval request message from the serving base station, where the user equipment context retrieval request message is used to request a user equipment context; The migrating the user equipment context to the serving base station includes: Sending a user equipment context retrieval response message to the serving base station, where the user equipment context retrieval response message carries the user equipment context; After migrating the user equipment context to the serving base station, the method further includes: A user equipment context release message is received from the serving base station, and the stored user equipment context is released, wherein the user equipment context release message is used to indicate the release of the stored user equipment context.

5. The data transmission method according to claim 4, characterized in that: The retrieve user equipment context response message also carries at least one of the following information: a data packet size and frequency allowed to be transmitted, and auxiliary information, wherein the auxiliary information is used to perform SDT indication on data to be transmitted.

6. The data transmission method according to claim 1 or 2, characterized in that: Before migrating the user equipment context to the serving base station, the method further includes: Sending a paging message to the serving base station, where the paging message carries first indication information; wherein the first indication information is used to indicate triggering the MT-SDT; After migrating the user equipment context to the serving base station, the method further includes: A user equipment context release message is received from the serving base station, and the stored user equipment context is released, wherein the user equipment context release message is used to indicate the release of the stored user equipment context.

7. The data transmission method according to claim 1, characterized in that: The method further comprises: If it is determined not to perform the user equipment context migration, receiving a user equipment context retrieval request message from the serving base station, and sending a user equipment context retrieval failure message and the downlink data or signaling to the serving base station; The user equipment context retrieval request message is used to request a user equipment context, and the user equipment context retrieval failure message is used to notify the serving base station that all user equipment contexts cannot be acquired.

8. The data transmission method according to claim 1, characterized in that: The method further comprises: If it is determined that the user equipment context migration is not to be performed, sending a user equipment partial context setting request message to the serving base station, wherein the user equipment partial context setting request message carries second configuration information, and the second configuration information is used to configure a data transmission mode in a scenario where the user equipment context migration is not performed; Send part of the user equipment context and the downlink data or signaling to the serving base station according to the second configuration information.

9. The data transmission method according to claim 8, characterized in that: The data transmission mode includes MT-SDT or SDT.

10. The data transmission method according to claim 8, characterized in that: The second configuration information includes a paging message, the partial user equipment context and a protocol data unit of a packet data convergence protocol layer; The paging message carries second indication information, where the second indication information is used to indicate not triggering MT-SDT; The protocol data unit of the packet data convergence protocol layer is used to store the downlink data or signaling.

11. A data transmission method, applied to a serving base station, characterized in that: The method comprises: Acquire downlink data or signaling for a user equipment from an anchor base station, wherein the user equipment is in a radio resource control RRC inactive state, the downlink data or signaling carries first configuration information, and the first configuration information is used to determine whether to perform user equipment context migration; the first configuration information includes auxiliary information, and the auxiliary information is used to perform a small data packet transmission SDT indication for data to be transmitted, and the auxiliary information includes at least one of the following information: subscription data, capabilities, data transmission statistics, data or signaling service characteristics and first indication information related to the SDT of the user equipment; the first indication information is used to indicate triggering mobile terminated small data packet transmission MT-SDT; If the anchor base station determines to perform the user equipment context migration, the user equipment context is received from the anchor base station, and the downlink data or signaling is sent to the user equipment.

12. The data transmission method according to claim 11, characterized in that: The sending the downlink data or signaling to the user equipment includes: The downlink data or signaling is sent to the user equipment in MT-SDT mode.

13. The data transmission method according to claim 11 or 12, characterized in that: The first configuration information also includes at least one of the following information: radio bearer and data packet size.

14. The data transmission method according to claim 11 or 12, characterized in that: Before receiving the user equipment context from the anchor base station, the method further includes: Sending a user equipment context retrieval request message to the anchor base station, where the user equipment context retrieval request message is used to request the user equipment context; The receiving a user equipment context from the anchor base station comprises: receiving a user equipment context retrieval response message from the anchor base station, wherein the user equipment context retrieval response message carries the user equipment context; After receiving the user equipment context from the anchor base station, the method further includes: A user equipment context release message is sent to the anchor base station, where the user equipment context release message is used to indicate the release of the stored user equipment context.

15. The data transmission method according to claim 14, characterized in that: The retrieve user equipment context response message also carries at least one of the following information: a data packet size and frequency allowed to be transmitted, and auxiliary information, wherein the auxiliary information is used to perform SDT indication on data to be transmitted.

16. The data transmission method according to claim 11 or 12, characterized in that: Before receiving the user equipment context from the anchor base station, the method further includes: receiving a paging message from the anchor base station, where the paging message carries first indication information, wherein the first indication information is used to indicate triggering of MT-SDT; After receiving the user equipment context from the anchor base station, the method further includes: A user equipment context release message is sent to the anchor base station, where the user equipment context release message is used to indicate the release of the stored user equipment context.

17. The data transmission method according to claim 11, characterized in that: The method further comprises: If the anchor base station determines not to perform the user equipment context migration, sending a user equipment context retrieval request message to the anchor base station, and receiving a user equipment context retrieval failure message and the downlink data or signaling from the anchor base station; The user equipment context retrieval request message is used to request the user equipment context, and the user equipment context retrieval failure message is used to notify the serving base station that all user equipment contexts cannot be acquired.

18. The data transmission method according to claim 11, characterized in that: The method further comprises: If the anchor base station determines not to perform the user equipment context migration, receiving a user equipment partial context setting request message from the anchor base station, wherein the user equipment partial context setting request message carries second configuration information, and the second configuration information is used to configure a data transmission mode in a scenario where the user equipment context migration is not performed; Receive part of the user equipment context and the downlink data or signaling from the anchor base station according to the second configuration information, and send the downlink data or signaling to the user equipment.

19. The data transmission method according to claim 18, characterized in that: The data transmission mode includes MT-SDT or SDT.

20. The data transmission method according to claim 18, characterized in that: The second configuration information includes a paging message, the partial user equipment context and a protocol data unit of a packet data convergence protocol layer; The paging message carries second indication information, where the second indication information is used to indicate not triggering MT-SDT; The protocol data unit of the packet data convergence protocol layer is used to store the downlink data or signaling.

21. The data transmission method according to claim 11 or 12, characterized in that: After sending the downlink data or signaling to the user equipment, the method further includes: Sending an RRC release message to the user equipment, where the RRC release message is used to instruct the user equipment to enter an RRC inactive state or an idle state; or, An RRC recovery message is sent to the user equipment, where the RRC recovery message is used to instruct the user equipment to enter an RRC connected state.

22. A network device, characterized in that: The network device includes a memory and a processor, and the processor calls a computer program or code stored in the memory to execute the data transmission method according to any one of claims 1 to 21.

23. A computer-readable storage medium for storing a computer program or instruction, characterized in that: When the computer program or instruction is executed by a processor, the data transmission method according to any one of claims 1 to 21 is implemented.

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