Communication method and communication device

Abstract

The embodiments of the present application provide a communication method and a communication device. The method includes: an access network device sends first information, the first information is used to trigger a core network element to buffer downlink data of a terminal in an inactive state, and the access network device sends second information, the second information instructs the terminal to enter an inactive state. According to the method provided in the present application, the core network side can help the access network side to buffer downlink data of the terminal in an inactive state, so that the storage load of data buffering on the access network side can be reduced.

Description

[Technical Field]

[0001] TECHNICAL FIELD Embodiments of the present application relate to the field of communications, and more particularly to communication methods and devices. [Background technology]

[0002] Massive machine type communication (mMTC) is one of the key application scenarios for 5th generation (5G) networks, and is primarily aimed at various Internet of Things (IoT) service applications based on cellular networks. To meet the low power consumption requirements of IoT terminals, extended discontinuous reception (eDRX) power-saving technology has been introduced, which significantly reduces terminal power consumption and extends battery life. In each eDRX cycle, the terminal can only receive downlink data within a specified paging time window. At other times, the terminal is in a sleep state and does not receive downlink data.

[0003] In the prior art, a radio access network (RAN) device sets an eDRX cycle for a terminal in an inactive state, allowing the terminal to sleep in the inactive state. When a downlink arrives at the core network, the core network transmits downlink data to the RAN. The RAN then pages the terminal within the paging time window of the eDRX cycle, and transmits the buffered downlink data to the terminal after the paging is successful, i.e., after the terminal enters the connected state from the inactive state. In this case, long-term data buffering increases the storage load of the RAN. Summary of the Invention

[0004] The present application provides a communication method and a communication device, in which a core network side can help an access network side buffer downlink data of a terminal in an inactive state, so that the storage load of data buffering on the access network side can be reduced.

[0005] According to a first aspect, a communication method is provided. The method may be performed by an access network device, or may be performed by a component (e.g., a chip or a circuit) of the access network device. This is not limited. For ease of description, the following uses an example in which the method is performed by an access network device for explanation.

[0006] The method may include: the access network device transmitting first information, the first information being used to trigger buffering of downlink data of the terminal in an inactive state in a core network element; and the access network device transmitting second information to the terminal, the second information instructing the terminal to enter the inactive state.

[0007] For example, the core network element here may be a session management function network element or a user plane function network element.

[0008] In the above technical solution, the access network device sends the first information, which can ensure that the core network recognizes the state change of the UE, that is, the core network element recognizes that the UE enters the inactive state from the connected state, and can help the access network side buffer downlink data in the inactive state, so that the storage load of data buffering on the access network side can be reduced.

[0009] With reference to the first aspect, in some implementations of the first aspect, the first information includes eDRX parameters, which are used by the terminal to sleep in an inactive state, and the eDRX parameters include an eDRX cycle; or the first information includes a first duration, which is a time determined by the access network device to buffer downlink data of the terminal in an inactive state in a core network element.

[0010] With reference to the first aspect, in some implementations of the first aspect, transmitting the first information by the access network device includes transmitting the first information by the access network device when the eDRX cycle is equal to or greater than a first cycle threshold, for example, the first cycle threshold is 10.24 seconds.

[0011] With reference to the first aspect, in some implementations of the first aspect, the access network device transmitting the first information includes the access network device transmitting the first information to an access and mobility management function network element, and the first information is used to trigger the access and mobility management function network element to decide to buffer downlink data of the terminal in an inactive state in a core network element.

[0012] With reference to the first aspect, in some implementations of the first aspect, the method further includes, when the terminal enters a connected state, the access network device sending first indication information, wherein the first indication information indicates that the terminal is in the connected state.

[0013] With reference to the first aspect, in some implementations of the first aspect, the method further includes the access network device receiving second indication information, the second indication information indicating that downlink data of the terminal is buffered in a core network element, and the access network device paging the terminal based on the second indication information.

[0014] According to a second aspect, a communication method is provided. The method may be performed by an access and mobility management function network element, or may be performed by a component (e.g., a chip or a circuit) of the access and mobility management function network element. This is not limited. For ease of description, the following uses an example in which the method is performed by the access and mobility management function network element for explanation.

[0015] The method may include: an access and mobility management function network element receiving first information from an access network device, the first information being used to trigger buffering of downlink data of the terminal in an inactive state in a core network element; and the access and mobility management function network element sending third instruction information to a session management function network element based on the first information, the third instruction information instructing buffering of downlink data of the terminal in an inactive state in the core network element.

[0016] For example, the core network element here may be a session management function network element or a user plane function network element.

[0017] For the advantageous effects of the second aspect, please refer to the description of the first aspect, and the details will not be described again here.

[0018] With reference to the second aspect, in some implementations of the second aspect, the first information includes eDRX parameters, which are used by the terminal to sleep in an inactive state, and the eDRX parameters include an eDRX cycle; or the first information includes a first duration, which is a time determined by the access network device to buffer downlink data of the terminal in an inactive state in a core network element.

[0019] With reference to the second aspect, in some implementations of the second aspect, the method further includes the access and mobility management function network element sending a second duration to the session management function network element, where the second duration is used to determine a third duration, where the third duration is a duration determined by the session management function network element for buffering downlink data of the terminal in an inactive state in the core network element, and the second duration is a duration determined by the access and mobility management function network element for buffering downlink data of the terminal in an inactive state in the core network element.

[0020] With reference to the second aspect, in some implementations of the second aspect, the method further includes the access and mobility management function network element determining a second lifetime based on the first information.

[0021] With reference to the second aspect, in some implementations of the second aspect, the method further includes: the access and mobility management function network element sending first query information to the session management function network element, where the first query information is used to query whether the core network element supports buffering of downlink data of the terminal in an inactive state; and the access and mobility management function network element receiving indication information from the session management function network element, where the fourth indication information is used to confirm that the core network element supports buffering of downlink data of the terminal in an inactive state.

[0022] According to a third aspect, a communication method is provided. The method may be performed by a core network element, or may be performed by a component (e.g., a chip or a circuit) of the core network element. For ease of description, the following uses an example in which the method is performed by the core network element for illustration.

[0023] The method may include: a core network element receiving third instruction information, the third instruction information instructing the core network element to buffer downlink data of the terminal in an inactive state; and the core network element buffering the downlink data of the terminal in an inactive state in the core network element based on the third instruction information.

[0024] For example, the core network element is a session management function network element or a user plane function network element.

[0025] The following technical solutions are based on the core network element receives the third indication information, thereby ensuring that the core network recognizes the state change of the UE, i.e., the core network element recognizes that the UE enters an inactive state from a connected state, and can help the access network device buffer downlink data in the inactive state. In this way, the storage load of data buffering in the access network device can be reduced.

[0026] With reference to the third aspect, in some implementations of the third aspect, the method further includes: a core network element receiving first indication information, the first indication information indicating that the terminal is in a connected state; and the core network element transmitting downlink data of the terminal buffered in the core network element to the access network device based on the first indication information.

[0027] With reference to the third aspect, in some implementations of the third aspect, the method further includes, when downlink data of the terminal arrives at the core network element, the core network element sending fifth indication information, wherein the fifth indication information indicates that the downlink data of the terminal has arrived at the core network element and that the core network element has started buffering the downlink data of the terminal.

[0028] With reference to the third aspect, in some implementations of the third aspect, the method further includes, when a buffering time of the downlink data of the terminal in an inactive state in the core network element exceeds a third duration, the core network element directly delivering or discarding the buffered downlink data of the terminal, where the third duration is a duration determined by the session management function network element for buffering the downlink data of the terminal in an inactive state in the core network element.

[0029] With reference to the third aspect, in some implementations of the third aspect, the core network element is a session management function network element, and the method further includes: the core network element receiving first query information from the access and mobility management function network element, where the first query information is used to query whether the core network element supports buffering of downlink data of the terminal; and the core network element sending fourth indication information to the access and mobility management function network element, where the fourth indication information is used to confirm that the core network element supports buffering of downlink data of the terminal in an inactive state.

[0030] According to a fourth aspect, there is provided a communication device configured to perform the method provided in the first, second or third aspect. Specifically, the device may include units and / or modules, such as a processing unit and / or a communication unit, configured to perform the method of any one of the first, second or third aspects and possible implementations of the first, second or third aspects.

[0031] In implementation, the apparatus is a device or a network element. When the apparatus is a device or a network element, the communication unit may be a transceiver or an input / output interface, and the processing unit may be at least one processor. Optionally, the transceiver may be a transceiver circuit. Optionally, the input / output interface may be an input / output circuit.

[0032] In other implementations, the apparatus is a chip, chip system, or circuit used in a device or network. When the apparatus is a chip, chip system, or circuit used in a terminal device, the communication unit may be an input / output interface, interface circuit, output circuit, input circuit, pin, associated circuit, etc. on the chip, chip system, or circuit, and the processing unit may be at least one processor, processing circuit, logic circuit, etc.

[0033] According to a fifth aspect, there is provided a communications apparatus, the apparatus including at least one processor, the at least one processor coupled to at least one memory, the at least one memory configured to store computer programs or instructions, the at least one processor configured to retrieve the computer programs or instructions from the at least one memory and execute the computer programs or instructions so that the communications apparatus performs a method of any one of the first aspect, the second aspect or the third aspect and possible implementations of the first aspect, the second aspect or the third aspect.

[0034] In implementations, the apparatus is a device or a network element.

[0035] In other implementations, the apparatus is a chip, chip system, or circuit used in a device or network element.

[0036] According to a sixth aspect, the present application provides a processor configured to perform the method provided in the above aspect.

[0037] Operations such as transmitting and acquiring / receiving associated with a processor may be understood as operations such as outputting and receiving or inputting of the processor, or operations such as transmitting and receiving performed by radio frequency circuits and antennas, unless otherwise specified or provided that such operations do not contradict the actual functionality or internal logic of the operations in the relevant description.

[0038] According to a seventh aspect, the present application provides a computer-readable medium. The computer-readable medium stores a computer program (which may also be referred to as code or instructions). When the computer program is executed on a computer, the computer can perform the method of the above aspect.

[0039] According to an eighth aspect, the present application provides a computer program product, which includes a computer program (which may also be referred to as code or instructions), which, when executed, enables a computer to perform the method of the above aspect.

[0040] According to a ninth aspect, the present application provides a communication system including the above-mentioned access network device, an access and mobility management function network element, a session management function network element, and a user plane function network element, or including the above-mentioned access network device, access and mobility management function network element, and session management function network element. [Brief explanation of the drawings]

[0041] [Figure 1] 1 is a schematic diagram of a network architecture applicable to embodiments of the present application; [Figure 2] 1 is a simplified flowchart of a communication method according to the present application. [Figure 3] 4 is a schematic flow chart of another communication method according to the present application. [Figure 4] 4 is a schematic flowchart of another communication method according to the present application. [Figure 5] 4 is a schematic flowchart of another communication method according to the present application. [Figure 6] 1 is a block diagram of a communication device 1100 according to an embodiment of the present application. [Figure 7] 12 is a block diagram of a communication device 1200 according to an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0042] The following describes the technical solution of the present application with reference to the accompanying drawings.

[0043] The technical solutions in the embodiments of the present application may be applied to various communication systems, such as a long term evolution (LTE) system, an LTE frequency division duplex (FDD) system, an LTE time division duplex (TDD) system, a universal mobile telecommunications system (UMTS), a worldwide interoperability for microwave access (WiMAX) communication system, a fifth generation (5G) system, a new radio (NR) system, or a future network. The 5G mobile communication system described in the present application includes a non-standalone (NSA) 5G mobile communication system or a standalone (SA) 5G mobile communication system. The technical solutions provided in the present application may also be applied to future communication systems, such as a sixth generation mobile communication system. Alternatively, the communication system may be a public land mobile network (PLMN), a device-to-device (D2D) communication system, a machine-to-machine (M2M) communication system, an internet of things (IoT) communication system, or other communication system.

[0044] FIG. 1 is a schematic diagram of a network architecture applicable to embodiments of the present application.

[0045] As shown in Figure 1, a 5G system (5th generation system, 5GS) is used as an example of a network architecture. The network architecture may include, but is not limited to, a network slice selection function (NSSF), an authentication server function (AUSF), a unified data management (UDM), a network exposure function (NEF), a network repository function (NRF), a policy control function (PCF), an application function (AF), an access and mobility management function (AMF), a session management function (SMF), a user equipment (UE), a radio access network device, a user plane function (UPF), and a data network (DN).

[0046] The DN may be the Internet. The NSSF, AUSF, UDM, NEF, NRF, PCF, AF, AMF, SMF, and UPF are network elements in the core network. Since the 5G system is used as an example in Figure 1, the core network elements may be called a 5G core network (5GC or 5GCN).

[0047] The following is a brief description of the network elements shown in FIG.

[0048] 1. User equipment (UE) may include various portable devices with wireless communication capabilities, in-vehicle devices connected to a wireless modem, wearable devices, computing devices or other processing devices, and various forms of terminals, mobile stations (MS), terminals, or soft terminals, such as water meters, electricity meters, and sensors.

[0049] For example, the user equipment in the embodiments of the present application may be an access terminal, a subscriber unit, a subscriber station, a mobile station, a relay station, a remote station, a remote terminal, a mobile device, a user terminal, terminal equipment, a wireless communication device, a user agent, or user equipment. The user equipment may alternatively be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop station, a personal digital assistant (PDA), a mobile device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a wearable device, a user equipment in a 5G network, a user equipment in a future public land mobile network (PLMN), a user equipment in a future Internet of Vehicles, etc. This is not a limitation of the embodiments of the present application.

[0050] By way of example, and not limitation, in embodiments of the present application, a wearable device, which may also be referred to as a wearable intelligent device, is a general term for wearable devices, such as glasses, gloves, watches, clothes, and shoes, that are intelligently designed and arranged for everyday wear by using wearable technology. A wearable device is a portable device that is worn directly on a user's body or integrated into the user's clothing or accessories. A wearable device is not only hardware, but also implements powerful functions through software support, data exchange, and cloud interaction. Generalized wearable intelligent devices include full-featured large devices that can implement full or partial functions without relying on a smartphone, such as smart watches or smart glasses, and devices that focus on only one type of application function and need to cooperate with other devices such as smartphones, such as various smart bands or smart jewelry for monitoring body signs.

[0051] Furthermore, in the embodiments of the present application, the user device may alternatively be a user device in an Internet of Things system. IoT is an important part of the future development of information technology. The main technical feature of IoT is that items are connected to a network by using communication technology to implement interconnections between people and machines and between things. In the embodiments of the present application, IoT technology can achieve massive connectivity, wide coverage, and terminal power saving by using narrow band (NB) technology, for example. Furthermore, in the embodiments of the present application, the user device may alternatively include a sensor such as an intelligent printer, a train detector, or a gas station. The main functions include collecting data (some user devices), receiving control information and downlink data from access network devices, transmitting electromagnetic waves, and transmitting uplink data to access network devices.

[0052] 2. A (radio) access network ((R)AN) is configured to provide network access functionality to authenticated user devices within a specific area and can use transmission tunnels with different qualities based on user device level, service requirements, etc.

[0053] The (R)AN manages radio resources and provides access services to user equipment for transferring control signals and user equipment data between the user equipment and the core network. The (R)AN can also be understood as a base station in a conventional network.

[0054] For example, the access network device in the embodiments of the present application may be any communication device with radio transmission and reception capabilities for communicating with user equipment, such as an evolved NodeB (eNB), a radio network controller (RNC), a NodeB (NodeB, NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (home evolved NodeB, HeNB, or home NodeB, HNB), a baseband unit (BBU), or an access point (AP), a wireless relay node, a wireless backhaul node, a transmission point (TP), a transmission and reception point (TP), or a wireless fidelity (Wi-Fi) system. Alternatively, it may be a gNB or a transmission point (TRP or TP) in a 5G system such as an NR system, or one antenna panel or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system, or it may be a network node forming a gNB or a transmission point, for example, a baseband unit (BBU) or a distributed unit (DU).

[0055] In some configurations, a gNB may include a central unit (CU) and a DU. The gNB may further include an active antenna unit (AAU). The CU implements some of the functions of the gNB, and the DU implements some of the functions of the gNB. For example, the CU is responsible for processing non-real-time protocols and services and implements functions of the radio resource control (RRC) layer and packet data convergence protocol (PDCP) layer. The DU is responsible for processing physical layer protocols and real-time services and implementing functions of the radio link control (RLC) layer, media access control (MAC) layer, and physical (PHY) layer. The AAU implements some physical layer processing functions, radio frequency processing, and active antenna-related functions. Information at the RRC layer is ultimately converted to or from information at the PHY layer. Therefore, in this architecture, higher layer signaling such as RRC layer signaling may be considered to be transmitted by the DU or by the DU and AAU. It may be understood that an access network device may be a device including one or more of a CU node, a DU node, and an AAU node. Furthermore, a CU may be classified as an access network device in an access network (radio access network, RAN), or a CU may be classified as an access network device in a core network (CN). This is not a limitation in the present application.

[0056] 3. AMF is primarily used for functions such as access control, mobility management, registration, and deregistration.

[0057] 4. The SMF is mainly used for user plane network element selection, user plane network element redirection, internet protocol (IP) address allocation for terminal devices, session establishment, modification, and release, and QoS control.

[0058] 5. The UPF is mainly used for receiving and forwarding user plane data. For example, the UPF may receive user plane data from the DN and send the user plane data to the terminal device via the AN device. The UPF may also receive user plane data from the terminal device via the AN device and forward the user plane data to the DN.

[0059] 6. NEF is primarily configured to securely expose the services, capabilities, etc. provided by 3GPP network functions to the outside world.

[0060] 7. The PCF is primarily configured to derive a unified policy framework for network operation and provide policy rule information, etc. to control plane network elements (e.g., AMF or SMF).

[0061] 8. The AF is primarily configured to interact with the PCF to provide services for the 3GPP network, for example to perform policy control.

[0062] 9. The network slice selection function (NSSF) is mainly used for network slice selection.

[0063] 10. UDM is mainly used for managing UE subscription data, including storing and managing UE identifiers, UE access authentication, etc.

[0064] 11. DN is mainly used for operator networks that provide data services to UEs, such as the Internet, third-party service networks, and IP multimedia service (IMS) networks.

[0065] 12.AUSF is primarily used for user authentication etc.

[0066] 13. The NRF is primarily configured to store network functions, description information of services provided by network function entities, etc.

[0067] In the network architecture, the N1 interface is the reference point between the terminal and the AMF entity, the N2 interface is the reference point between the (R)AN and the AMF entity and is used to transmit non-access stratum (NAS) messages, etc., the N3 interface is the reference point between the (R)AN and the UPF entity and is used to transmit user plane data, etc., the N4 interface is the reference point between the SMF entity and the UPF entity and is used to transmit information such as tunnel identifier information, data buffering indication information, and downlink data notification messages for the N3 connection, and the N6 interface is the reference point between the UPF entity and the DN and is used to transmit user plane data, etc.

[0068] It should be understood that the names of the network elements and communication interfaces between the network elements in FIG. 1 are basically described simply by using those specified in current protocols as examples. However, the embodiments of the present application are not limited to application to currently known communication systems. Therefore, when current protocols are used as examples for description, all standard names that appear are functional descriptions. Specific names such as network elements, interface signaling, etc. are not limited in the present application and only indicate the functions of the network elements, interfaces, or signaling, and may be extended to other systems accordingly.

[0069] It should be further understood that the above network architecture applicable to the embodiments of the present application in Figure 1 is merely an example for describing the network architecture applicable to the embodiments of the present application, and the network architecture applicable to the embodiments of the present application is not limited thereto. Any network architecture that can implement the functions of the above network elements is applicable to the embodiments of the present application.

[0070] It should be further understood that functions or network elements such as the AMF, SMF, UPF, PCF, UDM, NSSF, and AUSF shown in Figure 1 may be understood as network elements configured to implement different functions, and may, for example, be combined into network slices as needed. These network elements may be independent devices, or may be integrated into the same device to implement different functions, or may be network components within a hardware device, or may be software functions running on dedicated hardware, or may be virtualized functions instantiated on a platform (e.g., a cloud platform). The specific form of the network elements is not limited by this application.

[0071] It should be further understood that the above names are defined merely to distinguish between different functions and should not constitute any limitation on the present application. The present application does not exclude the possibility that other names may be used in 6G networks and other future networks. For example, in a 6G network, some or all of the above network elements may still use 5G terminology or may use other names.

[0072] To better understand the embodiments of the present application, the following will first describe the concepts in the embodiments of the present application.

[0073] 1. UE connection management (CM) states include an idle state (CM-IDLE), a connected state including an inactive state (CM-CONNECTED including RRC_INACTIVE), and a connected state (CM-CONNECTED). LTE originally had two states: idle and connected. The inactive state was introduced to reduce signaling and power consumption. The main factor affecting mobile phone power consumption is network connectivity. 5G is oriented toward the Internet of Everything, and network connectivity is critical for power consumption when rate demands are high. Furthermore, when a large number of devices transmit small amounts of data sporadically, excessive signaling overhead is caused. To balance power consumption with immediate access and reduce signaling overhead, the inactive state was introduced. In the inactive state, some RRC and NAC contexts are still retained in the UE, base station, and core network. In this case, the UE's state is almost the same as the idle state. Furthermore, the UE can instantly switch from an inactive state to a connected state, thereby reducing signaling overhead.

[0074] It should be understood that the CM state can be regarded as the RRC state of the UE recognized by the core network side. The following briefly describes the three RRC states:

[0075] (1) RRC_IDLE (Idle Mode): The RAN has no context for the UE, and there is no signaling connection between the UE and the RAN. In this state, the UE can receive system messages and paging messages and perform cell selection and reselection. When the UE needs to establish a connection to the network for a specific purpose (service request, location update, paging, etc.), the UE triggers RRC connection establishment. After the RRC connection is established, the UE enters the RRC connected state.

[0076] (2) RRC_INACTIVE (inactive mode): The connection between the RAN and the core network is maintained and no resources are allocated to the air interface, allowing for immediate service recovery and improving the experience of latency-sensitive applications. Furthermore, the power saving effect for users in the inactive state is close to that in the idle state, which can extend the battery life of mobile phones.

[0077] (3) RRC_CONNECTED (connected mode): The RAN has a context for the UE, and a signaling connection exists between the UE and the RAN. The UE can receive messages to control the UE to perform data transmission and handover, and to notify the UE of related scheduling information and system messages delivered by the RAN. The RAN can receive channel quality information fed back by the UE.

[0078] It should be noted that in the connected state, a connection is maintained between the UE and the RAN, and a connection is also maintained between the RAN and the core network. In the inactive state, the UE is detached from the RAN, but a connection is maintained between the RAN and the core network. Therefore, when the UE enters the inactive state from the connected state, the RAN recognizes that the UE is detached from the RAN, but a connection is still maintained between the RAN and the core network. In other words, the RAN can recognize that the UE is in the inactive state, but the core network can only recognize that the core network and the RAN are still in the connected state. Therefore, the core network cannot recognize that the UE is in the inactive state and considers the UE to be still in the connected state.

[0079] 2. Discontinuous Reception (DRX): For Internet of Things services, where data transmission is infrequent, data transmission is usually bursty. When no data is transmitted, the UE's receiving circuitry can be turned off to reduce power consumption, thereby extending battery life. During each DRX cycle, the terminal detects whether a downlink service is arriving. One DRX cycle is equal to the sum of the UE wake-up time and the UE sleep time. The UE wake-up time is the time during which the UE monitors the paging channel. During this time, the UE is in the awake state. The UE sleep time is the time during which the UE is asleep and does not monitor the paging channel to save power. During this time, the UE is in the sleep state. Because the DRX cycle is short, for example, the cycle can be 1.28 s, 2.56 s, 5.12 s, or 10.24 s, the downlink service can be considered to be reachable at any time. Therefore, DRX is applicable to services with high latency requirements but high power consumption.

[0080] 3. eDRX: eDRX has the same function as DRX. In both eDRX and DRX, the UE periodically enters a sleep state for some time to reduce battery consumption. In IoT systems, low-rate and low-frequency services require the UE to have extremely low power consumption. To further reduce the energy consumption of the UE and meet the requirements of IoT devices for extremely low power consumption, eDRX is introduced to accommodate the service functions of IoT devices. eDRX is an enhanced version of DRX that supports a longer sleep time, greatly reducing the UE's power consumption. Each eDRX cycle includes several DRX cycles, which form a paging time window (PTW). The value of the paging time window determines the window size and the number of paging attempts. The UE monitors the paging channel based on the DRX cycle within the PTW (DRX is short, and the terminal does not sleep and can be considered always reachable). For the remaining time within the eDRX cycle, the UE is in a sleep state and does not receive downlink data. Currently, an eDRX cycle in an inactive state typically does not exceed 10.24 seconds.

[0081] Please refer to Figure 2, which is a schematic flowchart of a communication method according to the present application. For ease of description, the network architecture shown in Figure 1 is used as an example for description in this embodiment of the present application.

[0082] S201: RAN sends first information, where the first information is used to trigger a core network element to buffer downlink data of a UE in an inactive state. For ease of understanding, an example in which the RAN sends the first information to an AMF is used for description in this step.

[0083] Accordingly, the AMF receives first information from the RAN. Optionally, the AMF determines to buffer downlink data of the UE in a core network element based on the first information.

[0084] For example, there may be two implementations in which the first information is used to trigger buffering of downlink data of the UE in an inactive state in a core network element.

[0085] First implementation: The RAN explicitly notifies the AMF to buffer downlink data of the UE in an inactive state in a core network element by using first information. For example, the first information is indication information A, which instructs the AMF to buffer downlink data of the UE in an inactive state in a core network element.

[0086] Second implementation: The RAN implicitly notifies the AMF to buffer the downlink data of the UE in an inactive state in a core network element by using parameters included in the first information. The following provides examples of two ways of implicitly indicating the first information.

[0087] (1) The first information includes eDRX parameters in an inactive state, the eDRX parameters including an eDRX cycle, the eDRX parameters being used by the terminal to sleep in the inactive state, and the eDRX parameters being used to trigger buffering of downlink data of the UE in the inactive state in a core network element.

[0088] The use of eDRX parameters by the terminal to sleep in an inactive state can be understood as the terminal sleeping in an inactive state based on the eDRX parameters. Specifically, in each eDRX cycle, the terminal receives downlink data only within the paging time window of the eDRX cycle. At other times, the terminal is in a sleep state and does not receive downlink data.

[0089] In a specific implementation, the method further includes the RAN determining eDRX parameters in the inactive state. For example, the terminal completes negotiation of eDRX parameters in the idle state with the AMF during the registration procedure. The AMF then delivers the eDRX parameters in the idle state to the RAN side, and the RAN side determines eDRX parameters in the inactive state based on the eDRX parameters in the idle state. The eDRX parameters in the idle state indicate the eDRX parameters used in the idle state, and the eDRX parameters in the inactive state indicate the eDRX parameters used in the inactive state. For example, the RAN knows that the eDRX cycle in the idle state is 10.24 s, and determines that the eDRX cycle in the inactive state is less than or equal to 10.24 s. For example, the RAN determines that the eDRX cycle in the inactive state is 5.12 s.

[0090] (2) The first information includes a first duration, and the first duration is a time for buffering downlink data of the UE in an inactive state in a core network element. The first duration is used to trigger buffering of the downlink data of the UE in an inactive state in a core network element. Optionally, the method further includes the RAN determining the first duration.

[0091] Optionally, the RAN determines the first duration based on the eDRX cycle in the inactive state. For example, when the RAN determines to buffer data in the core network based on the capability of the RAN, the RAN may estimate the first duration based on the eDRX parameters of the UE in the inactive state. For example, the first duration is equal to or greater than the eDRX cycle in the inactive state.

[0092] Optionally, the core network element that buffers the downlink data of the UE in the inactive state may be an SMF or a UPF, which is not specifically limited in this application.

[0093] Optionally, when the eDRX cycle in the inactive state is greater than or equal to a first cycle threshold, the RAN sends the first information to the AMF.

[0094] Optionally, the first cycle threshold may be set locally by the system, or may be specified in a protocol, or may be from another network element or a third party, and this is not a limitation of this application. For example, the first cycle threshold may be 10.24 seconds.

[0095] S202: The RAN sends second information to the UE, where the second information instructs the UE to enter an inactive state.

[0096] Optionally, S202 may be executed after S201, because: if the core network side agrees to perform buffering, the downlink data of the UE will be buffered in the core network; if the core network side does not agree to perform buffering, the core network still delivers the received data of the UE to the RAN side, and whether the UE enters the inactive state will not be affected.

[0097] Optionally, S202 may alternatively be executed after the RAN receives a feedback message indicating whether the core network element determines to perform buffering. For example, before S202, the method further includes: the RAN receiving a feedback message from the AMF, the feedback message indicating whether the core network supports buffering of downlink data of the UE in an inactive state; and the RAN determining second information based on the feedback message.

[0098] S203: The AMF sends third indication information to the core network element based on the first information, the third indication information instructing the core network element to buffer downlink data of the UE in an inactive state. Correspondingly, the core network element receives the third indication information from the AMF.

[0099] It can be understood that if the core network element is an SMF, the SMF can receive the third indication information from the AMF, or if the core network element is a UPF, the UPF can receive the third indication information from the AMF via the SMF.

[0100] The AMF sending third indication information to the core network element based on the first information includes the AMF determining, based on the first information, that the core network element supports buffering of downlink data for the UE in an inactive state, and then the AMF sending the third indication information to the core network element.

[0101] Optionally, if the first information includes eDRX parameters, the AMF may determine to buffer downlink data of the UE in an inactive state on the core network side based on the eDRX parameters.

[0102] Optionally, when the first information includes an eDRX parameter, the AMF may determine to buffer downlink data of the UE in an inactive state on the core network side based on both the eDRX parameter and another parameter, for example, the other parameter being one or more of information such as service capabilities of the UE and capabilities of the RAN.

[0103] Optionally, the AMF entity may be a reference point between the AMF and the SMF, and before determining to buffer the data in the core network element based on the first information, the AMF may further negotiate with the SMF to determine whether to buffer the data in the core network. Specifically, the method further includes S2031 to S2033. In this case, the core network element corresponding to S2031 to S2033 in Figure 2 is the SMF.

[0104] S2031: The AMF sends first query information to the SMF, where the first query information is used to query whether the core network element supports buffering of downlink data of the UE in an inactive state. Correspondingly, the SMF receives the first query information from the AMF.

[0105] S2032: The SMF determines whether downlink data of the UE in an inactive state should be buffered in the core network according to a local policy and the buffering capability of the SMF or UPF.

[0106] The local policy is a policy set by the operator on the network element side and is used to provide guidance for the SMF to perform some operations. In this scenario, the local policy may be a policy to determine whether buffering is possible in the core network for a UE in the current PLMN. The buffering capability is a capability that indicates whether the network element supports data buffering.

[0107] S2033: The SMF sends fourth indication information to the AMF, where the fourth indication information is used to check whether the core network element supports buffering of downlink data of the UE in an inactive state. Correspondingly, the AMF receives the fourth indication information from the SMF.

[0108] Optionally, the AMF may determine the second duration based on the first information. The second duration is a duration determined by the AMF for buffering downlink data of the UE in an inactive state in a core network element, or a duration required by the UE to enter a reachable state (a reachable state means a duration required to page the UE). For example, if the first information includes eDRX parameters, the AMF determines the second duration based on the eDRX parameters, or if the first information includes the first duration, the AMF determines the second duration based on the first duration. Optionally, the second duration is the same as the first duration.

[0109] Optionally, the AMF further transmits the second duration to the SMF, and the SMF determines a third duration based on the second duration. The third duration is a duration determined by the SMF for buffering downlink data of the UE in an inactive state in a core network element.

[0110] It can be understood that when the SMF performs buffering, the SMF determines a third duration based on the second duration, where the third duration is specifically a duration for buffering downlink data of the UE by the SMF.When the UPF performs buffering, the SMF determines a third duration based on the second duration, where the third duration is a duration for buffering downlink data of the UE by the UPF.

[0111] S204: The core network element buffers downlink data of the UE in an inactive state according to the third indication information.

[0112] It should be understood that the core network element here is a network element that receives the third indication information and actually buffers the data. In other words, if the core network element in step S203 is an SMF, the core network element in step S204 is an SMF, or if the core network element in step S203 is a UPF, the core network element in step S204 is a UPF.

[0113] In the above technical solution, through information exchange between the RAN and the AMF, the core network can recognize the CM state change of the UE, that is, the core network element can recognize that the UE enters the inactive state from the connected state, and can share the data buffering burden on the access network side. Furthermore, after a UE in the inactive state leaves the current cell, if there is no Xn interface between the original base station buffering the data and the target base station, according to the solution of the present application, the downlink data of the UE in the eDRX state is buffered in the core network, and the core network delivers the buffered data to the target base station to which the UE moves, thereby improving data transmission continuity and reducing signaling exchange in UE movement scenarios.

[0114] Optionally, after the core network buffers the downlink data of the UE, the solution further includes the core network delivering the buffered data to the UE. Still referring to Figure 2, the following describes a procedure by which a core network element delivers the buffered downlink data of the UE.

[0115] S205: When the UE enters a connected state, the RAN sends first indication information, where the first indication information indicates that the UE is in a connected state. Here, an example is used in which the RAN sends the first indication information to a core network element via AMF.

[0116] Accordingly, the core network element receives first indication information via the AMF, where the first indication information indicates that the UE is in a connected state.

[0117] It can be understood that if the core network element is an SMF, the RAN may send the first indication information to the SMF via the AMF. If the core network element is a UPF, the RAN may first send the first indication information to the SMF via the AMF, and then the SMF sends the first indication information to the UPF.

[0118] Optionally, the UE enters the actively connected state due to reasons such as a RAN notification area update (RNAU) or uplink data triggering.

[0119] Optionally, the UE enters the passively connected state upon paging by the RAN.

[0120] In implementation, if the UE enters a passively connected state, before S205, the method further includes S2051 to S2053.

[0121] S2051: The core network element sends fifth indication information when downlink data of the UE arrives at the core network element, and the fifth indication information indicates that the downlink data of the UE arrives at the core network element. element , indicating that the core network element has started buffering the downlink data of the UE. For ease of description, an example in which the core network element sends the fifth indication information to the AMF is used here for explanation.

[0122] It can be understood that if the core network element is an SMF, the SMF detects that the downlink data of the UE has arrived, starts buffering the downlink data, and sends the fifth indication information to the AMF. If the core network element is a UPF, the UPF detects that the downlink data of the UE has arrived, starts buffering the downlink data, and sends a downlink data arrival notification to the SMF, and the SMF sends the fifth indication information to the AMF.

[0123] S2052: The AMF sends second indication information to the RAN, where the second indication information indicates that the UE's downlink data is buffered in the core network element. Correspondingly, the RAN receives the second indication information from the AMF.

[0124] It can be understood that the second indication information is determined based on the fifth indication information.

[0125] S2053: The RAN pages the UE based on the second indication information.

[0126] Specifically, the RAN determines based on the second indication information that the core network has buffered downlink data for the UE to be transmitted, and the corresponding UE needs to be paged. Then, the RAN calculates a paging slot based on the eDRX parameters in the inactive state and broadcasts a paging message in the corresponding paging slot. The UE monitors the paging message in the paging slot within the corresponding paging time window and enters a connected state based on the paging message.

[0127] S206: The core network element transmits, based on the first indication information, downlink data of the UE in an inactive state buffered in the core network element to the RAN.

[0128] Correspondingly, the RAN receives the downlink data of the UE buffered in the core network element and forwards the downlink data to the UE.

[0129] It should be understood that after the core network element receives the first indication information, the core network element stops buffering the downlink data of the UE, and if the downlink data of the UE arrives at this time, the core network element directly forwards the downlink data to the RAN.

[0130] Optionally, if the core network element does not receive the first indication information and the buffering time of the UE's downlink data in the core network element exceeds a third duration, the core network element directly delivers or discards the buffered data. For example, when the UPF receives the UE's downlink data #1 at a first moment, the third duration begins to take effect. If the UPF does not receive the indication information to deliver the buffered data within the third duration starting from the first moment, the UPF directly delivers or discards the downlink data #1.

[0131] In the above technical solution, when the downlink data of the UE is buffered in the core network element, the buffered downlink data is delivered to the UE by triggering a paging procedure on the RAN side or by determining that the terminal has entered a connected state. In this way, the core network element buffers the downlink data, and the data buffering load of the RAN is reduced.

[0132] The following provides possible specific implementation procedures of S201 to S204 with reference to FIG.

[0133] S301: The RAN determines eDRX parameters for a UE in an inactive state, where the eDRX parameters include an eDRX cycle.

[0134] Optionally, the RAN determines the eDRX parameters in the inactive state based on the eDRX parameters of the UE in the idle state and the downlink data transmission traffic of the UE.

[0135] S302: Before the RAN prepares to drive the UE to enter the inactive state, the RAN determines whether to perform a subsequent procedure based on the value relationship between the eDRX cycle in the inactive state and the first cycle threshold.

[0136] In implementation, when the eDRX cycle is greater than the first cycle threshold, S303 is executed.

[0137] In other implementations, when the eDRX cycle is less than the first cycle threshold, the subsequent procedure does not need to be executed and the existing procedure may be executed.

[0138] Optionally, when the eDRX cycle is equal to the first cycle threshold, S303 may be executed, or an existing procedure may be executed, which is not specifically limited in this application.

[0139] S303: The RAN sends information #1 to the AMF network element. Correspondingly, the AMF network element receives information #1 from the RAN.

[0140] Information #1 is the same as the first information in S201. For details, please refer to the description of the first information. The details will not be described again here.

[0141] S304: The AMF network element determines, based on information #1, whether the UE's downlink data should be buffered in the core network element.

[0142] Optionally, if information #1 includes eDRX parameters, the AMF may determine whether to buffer data in a core network element based on the eDRX parameters and the UE's downlink data transmission traffic.

[0143] If the AMF determines based on information #1 that the UE's downlink data cannot be buffered in the core network element, the AMF sends indication information #1 to the RA, where indication information #1 indicates that the UE's downlink data cannot be buffered in the core network element.

[0144] If the AMF determines based on information #1 to buffer the UE's downlink data in the core network element, S305 is executed.

[0145] Optionally, before determining whether to perform buffering in the core network element based on information #1, the AMF may further negotiate with the SMF. In this case, the method further includes the following steps:

[0146] S3041: The AMF sends query information #1 to the SMF, where the query information #1 is used to query whether the core network element supports buffering. Correspondingly, the SMF receives the query information #1 sent by the AMF.

[0147] S3042: The SMF determines whether buffering in the core network element is supported and notifies the AMF of the result regarding whether buffering is supported.

[0148] Optionally, the SMF decides whether to perform buffering in the core network according to local policies and the buffering capabilities of the SMF or UPF / NEF.

[0149] S305: The AMF sends instruction information #2 to the SMF, which instructs the core network element to buffer the downlink data of the terminal in the inactive state. Correspondingly, the SMF receives instruction information #2 sent by the AMF.

[0150] Optionally, the AMF may further send a second duration to the SMF, which is used by the SMF to determine a third duration, which is a duration for buffering the terminal's downlink data in the core network element, and which is a duration determined by the AMF based on the eDRX parameters or the first duration for buffering the terminal's downlink data in the core network element, or a duration required by the UE to enter a network reachable state.

[0151] It can be understood that before receiving indication information #2, the SMF can consider the UE to be in a connected state, and after receiving indication information #2, the SMF can consider the UE to be in an inactive state.

[0152] It should be noted that after receiving indication information #2, the SMF further needs to determine whether the buffering is specifically performed in the SMF, UPF, or NEF.

[0153] S306: The SMF sends indication information #3 to the RAN via the AMF, and the indication information #3 is used to confirm that the UE's downlink data is buffered in the core network element.

[0154] Optionally, the SMF may further inform the RAN whether the buffering is specifically performed in the SMF or the UPF, which is not specifically limited in this application.

[0155] Optionally, when the SMF determines to perform buffering in the SMF, the SMF determines a third duration based on the second duration, where the third duration is specifically a duration for which the SMF buffers downlink data of the UE in an inactive state.

[0156] Optionally, when the SMF decides to perform buffering in the UPF, the method further includes the following steps:

[0157] S307: The SMF sends instruction information #4 to the UPF, which instructs the UPF to buffer the downlink data of the UE in the inactive state.

[0158] Accordingly, the UPF receives the indication information #4 sent by the SMF and buffers the downlink data of the UE.

[0159] It can be understood that before receiving instruction information #4, the UPF can consider the UE to be in a connected state, and after receiving instruction information #4, the UPF can consider the UE to be in an inactive state.

[0160] In a specific implementation, a new trigger condition tag (Tag) is added to a buffering action rule (BAR) in a packet detection rule (PDR), and the value of the tag indicates whether the BAR is enabled. For example, if the tag is 1 (i.e., an example of indication information #4), the UE is considered to be in an inactive state, the BAR is enabled, and the UPF buffers the UE's downlink data in the inactive state to the UPF according to the BAR. If the tag is 0, the UE is considered to be in a connected state, the BAR is disabled, and the UPF stops buffering and delivers the UE's buffered downlink data.

[0161] In another specific implementation, the eDRX sleep of the UE in the inactive state is performed at a fixed period, so the UPF may buffer and deliver downlink data of the UE based on the fixed period. For example, the SMF notifies the UPF to disable BAR within a paging time window at a fixed period and enable BAR at other times at the fixed period. In this case, the UPF buffers the downlink data of the UE within a BAR validity period corresponding to the fixed period and delivers the buffered downlink data of the UE within a BAR invalidity period corresponding to the fixed period, thereby reducing signaling overhead.

[0162] S308: The UPF sends an indication #5 to the RA, which indicates that the UE's downlink data is buffered in the UPF.

[0163] In a specific implementation, the UPF adds indication information #5 to the user plane data packet on the RAN side, or generates a null data packet and adds indication information #5 to it, and then sends the data packet to the RAN. Correspondingly, if the data packet is a null data packet, the RAN directly discards the null data packet.

[0164] Optionally, if buffering is performed in the UPF, only one of the indication information #5 and the indication information #3 may be sent.

[0165] Optionally, if the SMF determines to perform buffering in the UPF, the SMF determines a third duration based on the second duration and sends the third duration to the UPF, where the third duration is specifically a duration for buffering the downlink data of the UE in the UPF.

[0166] S309: The RAN instructs the UE to enter an inactive state.

[0167] Optionally, the RAN may instruct the UE to enter the inactive state before or after transmitting information #1, or when transmitting information #1. For reasons, please refer to the description of S202. The details will not be described again here.

[0168] Optionally, if the AMF determines at S304 that the UE's downlink data cannot be buffered in the core network element, the RAN may instruct the UE to enter an inactive state after receiving indication information #1.

[0169] Optionally, if the AMF determines at S304 to buffer the UE's downlink data in a core network element, the RAN may instruct the UE to enter an inactive state after receiving indication information #3 or indication information #5.

[0170] In the above technical solution, through information exchange between the RAN, the core network, and the AMF, the core network element can recognize the CM state change of the UE, i.e., the core network element can recognize that the UE has entered the inactive state from the connected state, and can help the access network side buffer downlink data in the inactive state. In this way, the storage load of data buffering on the access network side can be reduced.

[0171] Figure 3 specifically describes a procedure in which the RAN negotiates with a core network element to buffer the downlink data of the UE. After buffering the downlink data of the UE, the core network element can distribute the buffered data of the UE in two ways: active distribution and passive distribution. The following specifically describes specific procedures corresponding to the two distribution methods with reference to Figures 4 and 5.

[0172] Method 1: Active distribution

[0173] Please refer to Figure 4. Figure 4 is a schematic flowchart of another communication method according to the present application. For example, this embodiment will be described by using an example in which the UPF buffers downlink data of the UE.

[0174] S401: The RAN and the AMF complete negotiation to buffer the UE's downlink data in the UPF, and drive the UE to perform eDRX sleep in an inactive state. For specific procedures, please refer to the corresponding procedures in Figure 3. The details will not be described again here.

[0175] S402: When the UE downlink data arrives at the UPF side, the UPF sends indication information #6 to the SMF, indicating that the UE downlink data has arrived. Correspondingly, the SMF receives indication information #6 sent by the UPF.

[0176] Indication information #6 can also be understood as UE downlink data arriving and starting to be buffered on the UPF side.

[0177] S403: The SMF sends indication information #7 to the AMF, which indicates that the UE's downlink data is buffered in the core network element.

[0178] Accordingly, the AMF receives indication information #7 sent by the SMF.

[0179] Optionally, the SMF further sends query information #2 to the AMF, which is used to query the current SM state of the UE. Specifically, the SMF queries the AMF whether the UE is still in an inactive state at this moment, or when the UE in an inactive state is reachable. A UE in an inactive state being reachable means that the RAN can page the UE to enter a connected state.

[0180] S404: The AMF sends indication information #8 to the RAN, where the indication information #8 indicates that the UE's downlink data is buffered in the core network element.

[0181] Accordingly, the RAN receives the indication information #8 sent by the AMF and determines that the core network side has buffered data for the UE to be transmitted.

[0182] S405: After a certain period of time, when the UE is within a paging time window, the RAN broadcasts a paging message in a corresponding paging slot, and the paging message is used to page the UE to enter a connected state.

[0183] S406: The UE monitors a paging message in a paging slot within a corresponding paging time window, and enters a connected state based on the paging message.

[0184] S407: The RAN sends indication information #9 to the AMF, which indicates that the UE is in a connected state or that the UE has entered the connected state from an inactive state. Correspondingly, the AMF receives indication information #9 sent by the RAN.

[0185] S408: The AMF sends indication information #10 to the SMF, which is used to notify that the UE is in a connected state or that the UE has entered a connected state from an inactive state. Correspondingly, the SMF receives indication information #10 sent by the AMF.

[0186] It can be understood that before receiving the indication information #10, the SMF considers the UE to be in an inactive state, and after receiving the indication information #10, the SMF considers the UE to be in a connected state.

[0187] Optionally, indication #8 of S404 may alternatively instruct the RAN to check whether the UE is in a reachable state. Then, when the UE is in a reachable state, the RAN executes S407 and S408. Indication #9 and indication #10 both indicate that the UE in an inactive state is in a reachable state.

[0188] S409: The SMF sends instruction information #11 to the UPF, which instructs the UPF to send first data to the RAN, and the first data is the UE's downlink data buffered in the UPF.

[0189] It can be understood that before receiving the instruction information #11, the UPF considers the UE to be in an inactive state, and after receiving the instruction information #11, the UPF considers the UE to be in a connected state, or that the UE has entered the connected state from the inactive state, or that the UE in the inactive state is in a reachable state.

[0190] In a specific implementation, the SMF changes the trigger condition tag newly added to the BAR in S307 to 0 (i.e., an example of indication information #11) to indicate that the BAR is disabled, and the UPF executes the corresponding forwarding action rule (FAR) to forward the first data to the RAN. It can be understood that the corresponding tag being 0 indicates that the buffering action rule is disabled. Therefore, before the buffering action rule is enabled, the UPF stops buffering the UE's downlink data. When the UE's downlink data arrives, the UPF directly forwards the downlink data to the RAN.

[0191] S410: The UPF sends the first data to the RAN.

[0192] Accordingly, the RAN receives the first data, and then the RAN forwards the first data to the UE.

[0193] Optionally, if the UPF does not receive the indication information #11 and the buffering time of the first data in the core network element exceeds the third duration, the UPF directly delivers or discards the downlink first data.

[0194] In the above technical solution, when buffering data, the UPF notifies the RAN that the core network side has buffered downlink data of the UE to be transmitted, ensuring that the paging procedure on the RAN side is triggered when the UE is reachable, and ensuring that the buffered downlink data can be delivered to the UE in a timely manner.

[0195] Method 2: Passive Distribution

[0196] Please refer to Figure 5. Figure 5 is a schematic flowchart of a communication method according to the present application. For example, this embodiment will also be described by using an example in which the UPF buffers downlink data of the UE.

[0197] S501: The RAN and the AMF complete negotiation to buffer the UE's downlink data in the UPF, and drive the UE to perform eDRX sleep in an inactive state. For specific procedures, please refer to the corresponding procedures in Figure 3. The details will not be described again here.

[0198] S502: The RAN recognizes that the UE has actively entered a connected state, and the RAN sends indication information #9 to the AMF, which indicates that the UE is in a connected state.

[0199] Optionally, the UE enters the actively connected state due to reasons such as RAN notification area update (RNAU) and uplink data triggering.

[0200] S503: The AMF sends indication information #10 to the SMF, which is used to notify that the UE is in a connected state or that the UE has entered the connected state from an inactive state.

[0201] S504: The SMF sends instruction information #11 to the UPF, which instructs the UFP to send the first data to the RAN. Then, the UPF executes S507 based on the instruction information #11.

[0202] For a specific description of S503 and S504, please refer to the description of S408 and S409, and the details will not be described again here.

[0203] Optionally, in the method, S502 to S504 may not be performed, but S505 and S506 may be performed.

[0204] S505: The RAN sends an uplink data packet from the RAN to the UPF.

[0205] S506: The UPF determines that the UE is in a connected state based on the uplink data packet from the RAN, and then performs S507 for buffering in the UPF.

[0206] Optionally, the uplink data here may be an uplink data packet sent by the UE, or may be a null data packet configured and sent by the RAN to notify the UPF that the UE has entered a connected state by using the user plane. If the uplink data is a null data packet, the UPF will directly discard the null data packet.

[0207] S507: The UPF sends first data to the RAN, where the first data is downlink data of the UE buffered in the UPF.

[0208] Accordingly, the RAN receives the first data, and then the RAN forwards the first data to the UE.

[0209] In a specific implementation, the UPF determines that the UE has entered a connected state from an inactive state based on the user plane uplink data, and the UPF changes the trigger condition tag newly added to the BAR in S307 to 0 to indicate that the BAR is disabled, and then the UPF executes the corresponding FAR to forward the first data to the RAN.

[0210] In the above technical solution, the RAN notifies the core network side of the state change of the UE in a timely manner. If the core network side buffers downlink data of the UE in an inactive state, when the UE enters a connected state, the core network element will send the buffered data to the RAN to ensure that the buffered downlink data can be delivered to the UE in a timely manner.

[0211] It should be noted that the embodiment of the present application provides a specific procedure for buffering downlink data of a UE when the SMF and UPF are inactive. However, in practice, the core network element configured to buffer downlink data of a UE may alternatively be an NEF, which is not specifically limited in the present application.

[0212] It should be further noted that in the embodiment of the present application, network element #2 is used as an intermediate network element between network element #1 and network element #3, and network element #2 needs to forward the indication information A sent by network element #1 to network element #3. After network element #2 receives the indication information A sent by network element #1, the information sent to network element #3 may not actually be the previous indication information A, but may be indication information B. However, indication information B and indication information A have the same meaning. In this case, the present application can be described as follows: network element #1 sends indication information A to network element #3 via network element #2. Alternatively, network element #1 sends indication information A to network element #2, and network element #2 sends indication information A to network element #3. Alternatively, there may be other equivalent descriptions.

[0213] The method provided in the embodiment of the present application has been described in detail above with reference to Figures 2 to 5. The communication device provided in the embodiment of the present application will be described in detail below with reference to Figures 6 and 7. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment. Therefore, for the contents not described in detail, please refer to the above method embodiment. For the sake of brevity, the details will not be described again here.

[0214] In the embodiments of the present application, a sending end device or a receiving end device may be divided into functional modules according to the above-mentioned method examples. For example, each functional module may be obtained by division based on its corresponding function, or two or more functions may be integrated into one processing module. The integrated module may be implemented in the form of hardware or in the form of a software functional module. It should be noted that the division into modules in the embodiments of the present application is an example and is merely a logical division of functions. In actual implementation, there may be other division methods. An example in which each functional module is obtained by division based on its corresponding function is used below for explanation.

[0215] 6 is a block diagram of a communication device 1100 according to an embodiment of the present application. As shown, the communication device 1100 may include a transceiver unit 1110 and a processing unit 1120.

[0216] In a possible design, the communication device 1100 may be an access network device in the above method embodiments, or may be a chip configured to implement the functions of the access network device in the above method embodiments.

[0217] It should be understood that the communication device 1100 may correspond to the access network device of the method in the embodiment corresponding to Figures 2 to 5 of the present application. The communication device 1100 may include a unit configured to perform the method performed by the access network device of the method in the embodiment corresponding to Figures 2 to 5. Furthermore, the units in the communication device 1100 and other operations and / or functions described above may be used separately to implement corresponding procedures of the method in the embodiment corresponding to Figures 2 to 5. It should be understood that the specific processes by which the units perform the corresponding steps described above are described in detail in the method embodiment above. For the sake of brevity, the details will not be described here.

[0218] In another possible design, the communication device 1100 may be an AMF network element in the above method embodiment, or may be a chip configured to implement the functionality of the AMF network element in the above method embodiment.

[0219] It should be understood that the communication device 1100 may correspond to an AMF network element of the method in the embodiment corresponding to Figures 2 to 5 of the present application. The communication device 1100 may include a unit configured to perform the method performed by the AMF network element of the method in the embodiment corresponding to Figures 2 to 5. Furthermore, the units in the communication device 1100 and other operations and / or functions described above may be used separately to implement corresponding procedures of the method in the embodiment corresponding to Figures 2 to 5. It should be understood that the specific processes by which the units perform the corresponding steps described above are described in detail in the method embodiments above. For the sake of brevity, the details will not be described here.

[0220] In another possible design, the communication device 1100 may be an SMF network element in the above method embodiment, or may be a chip configured to implement the functionality of the SMF network element in the above method embodiment.

[0221] It should be understood that the communication device 1100 may correspond to an SMF network element of the method in the embodiment corresponding to Figures 2 to 5 of the present application. The communication device 1100 may include a unit configured to perform the method performed by the SMF network element of the method in the embodiment corresponding to Figures 2 to 5. Furthermore, the units in the communication device 1100 and other operations and / or functions described above may be used separately to implement corresponding procedures of the method in the embodiment corresponding to Figures 2 to 5. It should be understood that the specific processes by which the units perform the corresponding steps described above are described in detail in the method embodiment above. For the sake of brevity, the details will not be described here.

[0222] In another possible design, the communication device 1100 may be a UPF network element in the above method embodiment, or may be a chip configured to implement the functionality of the UPF network element in the above method embodiment.

[0223] It should be understood that the communication device 1100 may correspond to a UPF network element of the method in the embodiment corresponding to Figures 2 to 5 of the present application. The communication device 1100 may include a unit configured to perform the method performed by the UPF network element of the method in the embodiment corresponding to Figures 2 to 5. Furthermore, the units in the communication device 1100 and other operations and / or functions described above may be used separately to implement corresponding procedures of the method in the embodiment corresponding to Figures 2 to 5. It should be understood that the specific processes by which the units perform the corresponding steps described above are described in detail in the method embodiment above. For the sake of brevity, the details will not be described here.

[0224] It should be further understood that the transceiver unit 1110 of the communication device 1100 may correspond to the transceiver 1220 of the communication device 1200 shown in FIG. 7, and the processing unit 1120 of the communication device 1100 may correspond to the processor 1210 of the communication device 1200 shown in FIG. 7.

[0225] When the communication device 1100 is a chip, the chip includes a transceiver unit and a processing unit. The transceiver unit may be an input / output circuit or a communication interface. The processing unit may be a processor, a microprocessor, or an integrated circuit integrated on the chip. The transceiver unit 1110 is configured to perform signal reception and transmission operations of the communication device 1100, and the processing unit 1120 is configured to perform signal processing operations of the communication device 1100.

[0226] Optionally, the communication device 1100 further includes a storage unit 1130, which is configured to store instructions.

[0227] 7 is a block diagram of a communications device 1200 according to an embodiment of the present application. As shown, the communications device 1200 includes at least one processor 1210 and a transceiver 1220. The processor 1210 is coupled to a memory and configured to execute instructions stored in the memory to control the transceiver 1220 to transmit signals and / or receive signals.

[0228] Optionally, the communications device 1200 further includes a memory 1230 configured to store instructions.

[0229] It should be understood that the processor 1210 and the memory 1230 may be integrated into one processing unit, and the processor 1210 is configured to execute program code stored in the memory 1230 to implement the above-described functions. During specific implementations, the memory 1230 may be integrated into the processor 1210 or may be separate from the processor 1210.

[0230] The transceiver 1220 may include a receiver (also called a receiver) and a transmitter (also called a transmitter). The transceiver 1220 may further include one or more antennas. The transceiver 1220 may be a communication interface or interface circuit.

[0231] When the communication device 1200 is a chip, the chip includes a transceiver unit and a processing unit. The transceiver unit may be an input / output circuit or a communication interface. The processing unit may be a processor, a microprocessor, or an integrated circuit integrated on the chip.

[0232] An embodiment of the present application further provides a processing device including a processor and an interface, wherein the processor may be configured to perform the method in the above method embodiments.

[0233] It should be understood that the processing device may be a chip, for example, a field programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a system on a chip (SoC), a central processing unit (CPU), a network processor (NP), a digital signal processor (DSP), a microcontroller unit (MCU), a programmable logic device (PLD), or other integrated chip.

[0234] In the implementation process, the steps of the above method can be implemented by using a hardware integrated logic circuit in a processor or by using instructions in the form of software. The steps of the method disclosed with reference to the embodiments of the present application can be directly executed by a hardware processor, or can be executed by a combination of hardware and software modules in a processor. The software modules can be located in a storage medium mature in the art, such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, an electrically erasable programmable memory, or a register. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with the hardware of the processor. To avoid repetition, the details will not be described again here.

[0235] It should be noted that the processor in the embodiments of the present application may be an integrated circuit chip and have signal processing capabilities. In the implementation process, the steps in the above-described method embodiments may be implemented by using hardware integrated logic circuitry in the processor or by using instructions in the form of software. The processor may be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete-gate or transistor logic device, or a discrete hardware component. The processor may implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor may be a microprocessor, or the processor may be any conventional processor, etc. The steps of the methods described with reference to the embodiments of the present application may be directly executed by a hardware decoding processor or by a combination of hardware and software modules in the decoding processor. The software modules may be located in a storage medium established in the art, such as a random-access memory, a flash memory, a read-only memory, a programmable read-only memory, an electrically erasable programmable memory, or a register. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with the processor's hardware.

[0236] It will be understood that the memory in the embodiments of the present application may be volatile memory or nonvolatile memory, or may include both volatile and nonvolatile memory. Nonvolatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory may be random access memory (RAM) used as an external cache. By way of example, and not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchlink dynamic random access memory (SLDRAM), and direct rambus random access memory (DR RAM). It should be noted that memory for the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0237] According to the method provided in the embodiment of the present application, the present application further provides a computer program product, which includes computer program code, which, when executed on a computer, enables the computer to perform any of the methods in the embodiments shown in Figures 5 to 10.

[0238] According to the method provided in the embodiment of the present application, the present application further provides a computer-readable medium, which stores program code, which, when executed by a computer, can cause the computer to perform any of the methods in the embodiments shown in Figures 5 to 10.

[0239] According to the method provided in the embodiment of the present application, the present application further provides a system including the above-mentioned access network device, an AMF network element, an SMF network element, and a UPF network element.

[0240] According to the method provided in the embodiment of the present application, the present application further provides a system including the above-mentioned access network device, an AMF network element, and an SMF network element.

[0241] All or part of the above embodiments may be implemented by software, hardware, firmware, or any combination thereof. When software is used to implement the embodiments, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded into a computer and executed, the procedures or functions according to the embodiments of the present application are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from a computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, optical fiber, or digital subscriber line (DSL)) or wireless (e.g., infrared, radio wave, or microwave) transmission. The computer-readable storage medium may be any available medium accessible by a computer, or a data storage device such as a server or data center incorporating one or more available media. The usable media may be magnetic media (e.g., floppy disks, hard disks, or magnetic tapes), optical media (e.g., digital video discs (DVDs)), semiconductor media (e.g., solid state disks (SSDs)), etc.

[0242] The network side device and the terminal device in the apparatus embodiments correspond to the network side device or the terminal device in the method embodiments. Corresponding modules or units perform corresponding steps. For example, a communication unit (transceiver) performs the receiving step or the transmitting step in the method embodiments, and steps other than the transmitting step and the receiving step can be performed by a processing unit (processor). For the functions of specific units, please refer to the corresponding method embodiments. There may be one or more processors.

[0243] As used herein, terms such as "component," "module," and "system" are used to refer to computer-related entities, hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component may be, but is not limited to, a processor-executed process, a processor, an object, an executable, a thread of execution, a program, and / or a computer. As represented using the figures, both computing devices and applications running on computing devices may be components. One or more components may reside within a process and / or thread of execution, and a component may be located on one computer and / or distributed among two or more components. Furthermore, these components may execute from various computer-readable media that store various data structures. For example, components may communicate using local and / or remote processes based on signals with one or more data packets (e.g., data from two components interacting with other components in a local or distributed system and / or across a network such as the Internet that interacts with other systems using signals).

[0244] Those skilled in the art may realize that, in combination with the examples described in the embodiments disclosed herein, the units and algorithm steps may be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether a function is implemented by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but it should not be considered that the implementation goes beyond the scope of the present application.

[0245] For convenience and conciseness of description, it can be clearly understood by those skilled in the art that for the specific operating processes of the above systems, devices, and units, please refer to the corresponding processes in the above method embodiments, and the details will not be described again here.

[0246] It should be understood that in some embodiments provided herein, the disclosed systems, devices, and methods may be implemented in other ways. For example, the described device embodiments are merely examples. For example, the division into units is merely a logical division of function. During actual implementation, other division methods may exist. For example, multiple units or components may be combined or integrated into other systems, or some features may be ignored or not implemented. Furthermore, the shown or discussed interconnections or direct couplings or communication connections may be implemented through some interface, and indirect couplings or communication connections between devices or units may be implemented in electrical, mechanical, or other forms.

[0247] The units described as separate parts may or may not be physically separated, and the parts shown as units may or may not be physical units, and may be located in one place or distributed across multiple network units. Some or all of the units may be selected according to actual requirements to achieve the objectives of the solutions in the embodiments.

[0248] Furthermore, the functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit.

[0249] When a function is implemented in the form of a software functional unit and sold or used as an independent product, the function may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application may essentially be implemented in the form of a software product, or a portion of the technical solution, or a portion of the technical solution. A computer software product is stored in a storage medium and includes several instructions that instruct a computer device (which may be a personal computer, a server, or a network device) to perform all or some of the program steps described in the embodiments of the present application. The above storage medium includes any medium that can store program code, such as a USB flash drive, a removable hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0250] The above description is merely a specific implementation of the present application. However, the scope of protection of the present application is not limited thereto. Any modifications or replacements that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should fall within the scope of protection of the present application. Therefore, the scope of protection of the present application should be governed by the scope of protection of the claims.

Claims

1. 1. A communication method comprising: Sending first information to an access and mobility management function network element by an access network device, wherein the first information is used by the access and mobility management function network element to determine to buffer downlink data of a terminal in an inactive state in a core network element; receiving, by the access network device, a feedback message indicating that the core network element supports buffering of the downlink data for the terminal in the inactive state; sending, by the access network device, second information to the terminal based on the feedback message, the second information instructing the terminal to enter the inactive state; A method having the following.

2. The first information includes eDRX parameters, and the eDRX parameters include an eDRX cycle set by the access network device for the terminal in the inactive state; or The first information includes a first duration, and the first duration is a time determined by the access network device to buffer the downlink data of the terminal in the inactive state in the core network element. The method of claim 1.

3. The step of transmitting the first information by the access network device includes: transmitting, by the access network device, the first information when an eDRX cycle of the terminal in the inactive state is equal to or greater than a first cycle threshold.

3. The method according to claim 1 or 2.

4. The method comprises: and further comprising: when the terminal enters a connected state, sending, by the access network device, first indication information to the core network element, the first indication information indicating that the terminal is in the connected state.

3. The method according to claim 1 or 2.

5. The method comprises: receiving second indication information by the access network device, the second indication information indicating that the downlink data of the terminal is buffered in the core network element; and paging the terminal by the access network device based on the second indication information; Further comprising:

3. The method according to claim 1 or 2.

6. 1. A communication method comprising: receiving first information from an access network device by an access and mobility management function network element, wherein the first information is used by the access and mobility management function network to determine to buffer downlink data of a terminal in an inactive state in a core network element; determining, by the access and mobility management function network element, that the core network element supports buffering of the downlink data of the terminal in the inactive state, and sending a feedback message indicating the result of the determination to the access network device, wherein the feedback message is used by the access network device to instruct the terminal to enter the inactive state; sending, by the access and mobility management function network element, third indication information to a session management function network element based on the first information, the third indication information instructing the core network element to buffer the downlink data of the terminal in the inactive state; A method having the following.

7. The first information includes eDRX parameters, and the eDRX parameters include an eDRX cycle set by the access network device for the terminal in the inactive state; or The first information includes a first duration, and the first duration is a time determined by the access network device to buffer the downlink data of the terminal in the inactive state in the core network element. The method of claim 6.

8. The method comprises: further comprising transmitting a second duration by the access and mobility management function network element to the session management function network element, wherein the second duration is used to determine a third duration, the third duration being a duration determined by the session management function network element for buffering the downlink data of the terminal in the inactive state in the core network element, and the second duration being a duration determined by the access and mobility management function network element for buffering the downlink data of the terminal in the inactive state in the core network element.

8. The method according to claim 6 or 7.

9. The determination that the core network element supports buffering of the downlink data for the terminal in the inactive state, comprising: sending first query information by the access and mobility management function network element to the session management function network element, the first query information being used to query whether the core network element supports buffering of the downlink data of the terminal in the inactive state; receiving fourth indication information from the session management function network element by the access and mobility management function network element, the fourth indication information being used to confirm that the core network element supports buffering of the downlink data of the terminal in the inactive state; having 8. The method according to claim 6 or 7.

10. 1. A communication method comprising: receiving, by a core network element, first query information from an access and mobility management function network element, the first query information being used to query whether the core network element supports buffering of downlink data of a terminal in an inactive state; sending fourth indication information by the core network element to the access and mobility management function network element, the fourth indication information being used to confirm that the core network element supports buffering of the downlink data of the terminal in the inactive state; receiving third indication information from the access and mobility management function network by the core network element, the third indication information instructing the core network element to buffer the downlink data of the terminal in the inactive state; buffering, by the core network element, the downlink data of the terminal in the inactive state based on the third indication information; A method having the following.

11. The method comprises: receiving first indication information by the core network element, the first indication information indicating that the terminal is in a connected state; and transmitting, by the core network element, the downlink data of the terminal buffered in the core network element to an access network device based on the first indication information; Further comprising: The method of claim 10.

12. The method comprises: and further comprising: sending, by the core network element, fifth indication information to an access and mobility management function network element when the downlink data of the terminal arrives at the core network element, the fifth indication information indicating that the downlink data of the terminal has arrived at the core network element and that the core network element has started buffering the downlink data of the terminal.

12. The method according to claim 10 or 11.

13. The method comprises: and further comprising: when a buffering time of the downlink data of the terminal in the inactive state in the core network element exceeds a third duration, directly delivering or discarding the buffered downlink data of the terminal, the third duration being a duration determined by a session management function network element for buffering the downlink data of the terminal in the inactive state in the core network element.

12. The method according to claim 10 or 11.

14. The core network element is a session management function network element or a user plane function network element; 12. The method according to claim 10 or 11.

15. A communication device, a communication device having at least one processor coupled to at least one memory, the at least one processor configured to execute computer programs or instructions stored in the at least one memory such that the communication device performs the method of claim 1 or 2; Communication equipment.

16. A communication device, a communication device having at least one processor coupled to at least one memory, the at least one processor configured to execute computer programs or instructions stored in the at least one memory such that the communication device performs the method of claim 6 or 7; Communication equipment.

17. A communication device, comprising: a communication device having at least one processor coupled to at least one memory, the at least one processor configured to execute computer programs or instructions stored in the at least one memory such that the communication device performs the method of claim 10 or 11; Communication equipment.

18. A computer-readable storage medium storing computer instructions, comprising: The computer instructions, when executed on a computer, perform the method of claim 1 or 2. A computer-readable storage medium.

19. A computer-readable storage medium storing computer instructions, comprising: The computer instructions, when executed on a computer, perform the method according to claim 6 or 7. A computer-readable storage medium.

20. A computer-readable storage medium storing computer instructions, comprising: The computer instructions, when executed on a computer, perform the method according to claim 10 or 11. A computer-readable storage medium.

21. 1. A computer program comprising computer program code, The computer program code, when executed on a computer, performs the method according to claim 1 or 2. Computer program.

22. A computer program comprising computer program code, The computer program code, when executed on a computer, performs the method according to claim 6 or 7. Computer program.

23. A computer program comprising computer program code, The computer program code, when executed on a computer, performs the method according to claim 10 or 11. Computer program.

24. The network includes an access network device, an access and mobility management function network element, and a core network element, The access network device is configured to perform the method according to claim 1 or 2, The Access and Mobility Management Function network element is configured to perform the method of claim 6 or 7, The core network element is configured to perform the method according to claim 10 or 11. Communication system.

25. transmitting, by the access network device, first information used by the access and mobility management function network element to determine to buffer downlink data of the terminal in an inactive state in a core network element; receiving, by the access network device, a feedback message indicating that the core network element supports buffering of the downlink data for the terminal in the inactive state; transmitting, by the access network device, second information instructing the terminal to enter the inactive state based on the feedback message; receiving the first information from the access network device by the access and mobility management function network element; sending, by the access and mobility management function network element, third instruction information to the session management function network element based on the first information, the third instruction information instructing the core network element to buffer the downlink data of the terminal in the inactive state; receiving the third indication information by the core network element; buffering, by the core network element, the downlink data of the terminal in the inactive state based on the third indication information; A communication method comprising:

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