Communication method and device, and storage medium

Abstract

The embodiments of the present application provide a communication method and apparatus, as well as a storage medium. The method is used to page a terminal device participating in a multicast service using a paging message, so that the terminal device attempts to enter an RRC connected state to receive data of the multicast service. In the present application, the terminal device receives a first paging message and initiates a radio resource control RRC connection resumption when a first condition is met. The first condition includes that the first paging message includes an identifier of the first multicast service and does not include an identifier of the terminal device, or that the first paging message includes an identifier of the first multicast service and a first identifier of the terminal device, where the first identifier is associated with RAN paging. Since the first paging message may carry an identifier of the first multicast service, the terminal device corresponding to the first multicast service may be paged using the first paging message, so that the terminal device attempts to enter an RRC connected state based on the first paging message to receive data of the first multicast service.

Description

[Technical Field]

[0001] The present application relates to the field of communications, and in particular to communications methods and devices, and storage media. [Background technology]

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to Chinese Patent Application No. 202111236108.7, entitled "COMMUNICATION METHOD AND APPARATUS, AND STORAGE MEDIUM," filed with the State Intellectual Property Office of the People's Republic of China on October 22, 2021, the entirety of which is incorporated herein by reference.

[0003] In a wireless communication system, a network device may page a terminal device in an RRC idle state or an RRC inactive state by sending a paging message. Alternatively, the network device may send a short message service to inform a terminal device in an RRC idle state, an RRC inactive state, or an RRC connected state of a system information change, an earthquake and tsunami warning system (ETWS) notification, or a commercial mobile alert system (CMAS) notification. A terminal device in an RRC idle state or an RRC inactive state may enter an RRC connected state after receiving the paging message.

[0004] In order to effectively utilize mobile communication network resources, multicast broadcast service (MBS) is introduced by 3GPP. Multicast broadcast service provides a point-to-multipoint service in which a data source transmits data to multiple users in a mobile communication network, thereby implementing network resource sharing and improving resource utilization, especially for air interface resources.

[0005] Currently, in MBS, after a multicast service is deactivated, the terminal device may be in an RRC connected state, or alternatively, may be in an RRC idle state or an RRC inactive state. After a multicast service is activated, a terminal device in an RRC idle state or an RRC inactive state cannot successfully or immediately receive data of the multicast service. Summary of the Invention

[0006] The embodiments of the present application provide a communication method and apparatus, and a storage medium, which are used to page a terminal device participating in a multicast service using a paging message, so that the terminal device attempts to enter an RRC connected state to receive data of the multicast service.

[0007] According to a first aspect, an embodiment of the present application provides a communication method, in which a terminal device receives a first paging message and initiates a radio resource control (RRC) connection resumption when a first condition is met. The first condition includes: the first paging message includes an identifier of a first multicast service but does not include an identifier of the terminal device; or the first paging message includes an identifier of the first multicast service and a first identifier of the terminal device. The first identifier is associated with RAN paging.

[0008] Since the first paging message may carry an identifier of the first multicast service, a terminal device corresponding to the first multicast service may be paged using the first paging message, whereby the terminal device attempts to enter an RRC connected state based on the first paging message. The terminal device that has entered the RRC connected state may receive data of the first multicast service. It can be understood that according to the solution provided in the embodiments of the present application, a terminal device in an RRC inactive state is enabled to enter the RRC connected state. A solution is provided for a terminal device in an RRC inactive state that cannot successfully or immediately receive data of the first multicast service.

[0009] In a possible implementation, the terminal device initiating the RRC connection resumption may specifically include the terminal device transmitting a first message. The first message is used to request the RRC connection to be resumed. For example, the terminal device may transmit the RRC connection resumption to the network device, and the network device may resume the RRC connection based on the stored context of the terminal device, thereby allowing the terminal device to enter the RRC connected state more quickly.

[0010] In a possible implementation, when the terminal device determines to initiate RRC connection resumption, the terminal device may further determine an RRC connection resumption cause. There are several determination methods. For example, when the first paging message includes an identifier of the first multicast service and a first identifier of the terminal device, the terminal device may determine the first RRC connection resumption cause according to a first policy. The first policy includes at least one of an access identification, an RRC connection resumption cause corresponding to unicast, and a rule for determining the RRC connection resumption cause corresponding to unicast.

[0011] In another example, the terminal device may alternatively determine the first RRC connection resumption cause according to a second policy, the second policy including at least one of an access identification corresponding to multicast, an RRC connection resumption cause corresponding to multicast, and a rule for determining the RRC connection resumption cause corresponding to multicast.

[0012] In another example, the terminal device may alternatively determine the first RRC connection resumption cause according to a third policy, the third policy including at least one of an access identification, an RRC connection resumption cause corresponding to unicast and multicast, and a rule for determining the RRC connection resumption cause corresponding to unicast and multicast.

[0013] In another example, the terminal device may alternatively determine the first RRC connection resumption cause according to a first policy and a second policy. For example, the terminal device may determine the second RRC connection resumption cause according to the first policy. The terminal device may determine the third RRC connection resumption cause according to the second policy. The terminal device may determine one of the second RRC connection resumption cause and the third RRC connection resumption cause as the first RRC connection resumption cause. For example, the RRC connection resumption cause with the highest priority may be selected as the first RRC connection resumption cause from the second RRC connection resumption cause and the third RRC connection resumption cause.

[0014] When the first paging message includes an identifier of the first multicast service but does not include an identifier of the terminal device, the terminal device may determine a first RRC connection resumption cause according to a second policy.

[0015] In a possible implementation, after the terminal device receives a first paging message, the terminal device enters the RRC idle state when a second condition is met. The second condition includes that the first paging message includes an identifier of the first multicast service and a second identifier of the terminal device, where the second identifier is associated with CN paging, or that the first paging message includes the second identifier of the terminal device. In this way, when the second condition is met, the terminal device in the RRC inactive state can enter the RRC connected state from the RRC idle state. For example, after the terminal device enters the RRC idle state, the terminal device can send a second message. The second message is used to request setting up an RRC connection. In this way, the terminal device in the RRC inactive state can select a manner of entering the RRC connected state based on the content carried in the received first paging message. In addition, when the second condition is met, entering the RRC idle state can better match the manner of entering the RRC connected state by the terminal device in the unicast case.

[0016] In a possible implementation, the identifier of the first multicast service includes an identifier of the first multicast service in which the terminal device will participate. For example, the terminal device may pre-subscribe to the first multicast service. In this way, the terminal device may determine whether to respond to the first paging message based on the identifier of the first multicast service in the first paging message.

[0017] According to a second aspect, an embodiment of the present application provides a communication method, the method including: a first network device receiving a second paging message; the second paging message including a third identifier of a second multicast service; and the first network device performing one or more of the following:

[0018] The first network device triggers RAN paging, or the first network device pages the terminal device, and the terminal device is in an RRC inactive state and associated with the second multicast service, or the first network device sends a third paging message to the second network device, and the third paging message indicates to the second network device to page the terminal device.

[0019] Since the second paging message may trigger the first network device to start RAN paging, the first network device may not only page terminal devices that correspond to the second multicast service and are in an RRC idle state based on the second paging message, but also page terminal devices that are in an RRC inactive state, thereby reducing the delay when terminal devices in an RRC inactive state enter an RRC connected state.

[0020] In another case, the first network device pages the terminal device in the RRC inactive state after receiving the second paging message, thereby reducing the delay when the terminal device in the RRC inactive state enters the RRC connected state.

[0021] In yet another case, the first network device indicates to the second network device to page the terminal device in the RRC inactive state after receiving the second paging message, so that the delay when the terminal device in the RRC inactive state enters the RRC connected state can be reduced.

[0022] In a possible implementation, the first network device paging the terminal device may specifically include the first network device transmitting first control information and a fourth paging message. The first control information is used to schedule the fourth paging message, and the fourth paging message includes a third identifier of the second multicast service and / or an identifier of the terminal device, or the fourth paging message includes a fourth identifier of the second multicast service and / or an identifier of the terminal device. For example, the first network device may calculate a first paging occasion for the terminal device in an RRC inactive state and transmit the first control information on the first paging occasion, whereby the terminal device receives the fourth paging message based on the first control information.

[0023] In a possible implementation, the network device side is R NA Since the first network device does not need to be notified of the movement of the terminal device in the cell corresponding to RNA, the first network device paging the terminal device may particularly include the first network device paging the terminal device in the cell corresponding to RNA. In this way, the efficiency of paging the terminal device can be improved.

[0024] In a possible implementation, the first network device sends a third paging message to the second network device, where the third paging message includes one of: an identifier of the terminal device; an identifier of the terminal device and a DRX period of the terminal device; an identifier of the terminal device, a DRX period of the terminal device and a third identifier of the second multicast service, a fourth identifier of the second multicast service, or a fifth identifier of the second multicast service; or a third identifier of the second multicast service, a fourth identifier of the second multicast service, or a fifth identifier of the second multicast service.

[0025] In a possible implementation, the first network device is the last serving node of the terminal device. In this way, the efficiency of paging the terminal device can be improved.

[0026] In a possible implementation, the second network device is located in the RNA corresponding to the terminal device. In this way, the first network device indicates to the second network device in the RNA to page the terminal device, thereby improving the efficiency of paging the terminal device.

[0027] In a possible implementation, after receiving the second paging message, the first network device may further determine terminal devices based on a third identifier of the second multicast service. Specifically, terminal devices in an RRC idle state and terminal devices in an RRC inactive state may be determined. Based on this, terminal devices in an RRC idle state and terminal devices in an RRC inactive state may be paged.

[0028] Corresponding to any of the communication methods according to the first and second aspects, the present application further provides a communication device. The communication device may be any transmitting device or any receiving device that transmits data wirelessly, such as a communication chip, a terminal device, or a first network device (the first network device may be an access network device, a core network device, etc.). In the communication process, the transmitting device and the receiving device are relative to each other. In some communication processes, the communication device may be used as the first network device or a communication chip that can be used in the first network device. In some communication processes, the communication device may be used as the terminal device or a communication chip that can be used in the terminal device.

[0029] According to a third aspect, there is provided a communication device. The communication device includes a transceiver unit and a processing unit for performing any implementation of any communication method according to the first and second aspects. The transceiver unit is configured to perform functions related to transmission and reception. Optionally, the transceiver unit includes a receiving unit and a transmitting unit. In a design, the communication device is a communication chip, and the transceiver unit can be an input / output circuit or port of the communication chip.

[0030] In another design, the transceiver unit is a transmitter and a receiver. obtain .

[0031] Optionally, the communication device further comprises a module that may be configured to perform any implementation of any of the communication methods according to the first and second aspects.

[0032] According to a fourth aspect, there is provided a communication device, which is the aforementioned terminal device or first network device. The communication device comprises a processor and a memory. Optionally, the communication device further comprises a transceiver. The memory is configured to store a computer program or instruction. The processor is configured to retrieve the computer program or instruction from the memory and execute the computer program or instruction. When the processor executes the computer program or instruction in the memory, the communication device is enabled to perform any implementation of any communication method according to the first aspect and the second aspect.

[0033] Optionally, there are one or more processors and one or more memories.

[0034] Optionally, the memory may be integrated with the processor, or the memory may be located separately from the processor.

[0035] Optionally, the transceiver may comprise a transmitting machine (transmitter) and a receiving machine (receiver).

[0036] According to a fifth aspect, there is provided a communication device comprising a processor. The processor may be coupled to a memory and configured to perform a method according to either the first aspect or the second aspect and any one of possible implementations of the first aspect and the second aspect. Optionally, the communication device further comprises the memory. Optionally, the communication device further comprises a communication interface, the processor being coupled to the communication interface.

[0037] In an implementation, the communication device is a terminal device. When the communication device is a terminal device, the communication interface may be a transceiver or an input / output interface. Optionally, the transceiver may be a transceiver circuit. Optionally, the input / output interface may be an input / output circuit.

[0038] In another implementation, the communication device is a first network device. When the communication device is a first network device, the communication interface may be a transceiver or an input / output interface. Optionally, the transceiver may be a transceiver circuit. Optionally, the input / output interface may be an input / output circuit.

[0039] In yet another implementation, the communication device is a chip or chip system. When the communication device is a chip or chip system, the communication interface may be an input / output interface, an interface circuit, an output circuit, an input circuit, a pin, associated circuitry, etc. on the chip or chip system. The processor may alternatively be a processing circuit or a logic circuit.

[0040] According to a sixth aspect, there is provided a system, the system including the terminal device and a first network device.

[0041] According to a seventh aspect, there is provided 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 a method according to any possible implementation of the first aspect, or enables a computer to perform a method according to any implementation of the first and second aspects.

[0042] According to an eighth aspect, there is provided a computer-readable storage medium, which stores a computer program (which may also be referred to as code or instructions), which, when executed on a computer, enables the computer to perform a method according to any possible implementation of the first aspect, or to perform a method according to any implementation of the first and second aspects.

[0043] According to a ninth aspect, a chip system is provided. The chip system may include a processor. The processor may be coupled to a memory and configured to perform a method according to either the first aspect or the second aspect, or any one of possible implementations of the first aspect and the second aspect. Optionally, the chip system further includes a memory. The memory is configured to store a computer program (which may also be referred to as code or instructions). The processor is configured to call the computer program from the memory and execute the computer program, thereby causing a device on which the chip system is installed to perform a method according to either the first aspect or the second aspect, or any one of possible implementations of the first aspect and the second aspect.

[0044] According to a tenth aspect, there is provided a processing device comprising an input circuit, an output circuit and a processing circuit, the processing circuit being configured to receive a signal using the input circuit and to transmit a signal using the output circuit, thereby implementing a method according to either the first aspect or the second aspect and any one of the possible implementations of the first aspect and the second aspect.

[0045] In a specific implementation process, the processing device may be a chip, the input circuit may be an input pin, the output circuit may be an output pin, and the processing circuit may be a transistor, a gate circuit, a trigger, any logic circuit, etc. The input signal received by the input circuit may be, for example, but not limited to, received and input by a receiver, and the signal output by the output circuit may be, for example, but not limited to, output to a transmitter and transmitted by the transmitter, and the input circuit and the output circuit may be the same circuit, which is used as an input circuit and an output circuit at different times. The specific implementation of the processor and various circuits is not limited in the embodiments of the present application. [Brief explanation of the drawings]

[0046] [Figure 1] 1 is a schematic diagram of a possible system architecture to which embodiments of the present application are applicable; [Figure 2] FIG. 2 is a schematic diagram of another possible system architecture to which embodiments of the present application are applicable. [Figure 3a] 1 is a schematic flowchart of a communication method according to an embodiment of the present application; [Figure 3b] 1 is a schematic flowchart of a communication method according to an embodiment of the present application; [Figure 4] 1 is a schematic flowchart of a communication method according to an embodiment of the present application; [Figure 5] 1 is a schematic diagram of the structure of a communication device according to an embodiment of the present application; [Figure 6] FIG. 10 is a schematic diagram of the structure of another communication device according to an embodiment of the present application; [Figure 7] FIG. 10 is a schematic diagram of the structure of another communication device according to an embodiment of the present application; DETAILED DESCRIPTION OF THE INVENTION

[0047] 1 is a schematic diagram of an example of a system architecture according to an embodiment of the present application. As shown in FIG. 1, the system architecture includes a terminal device 11 and network devices 12 The terminal device includes a network device. 12 When a first condition is met, the terminal device may receive a first paging message from the terminal device.

[0048] The first condition includes one of: the first paging message includes an identifier of the first multicast service and does not include an identifier of the terminal device; and the first paging message includes an identifier of the first multicast service and a first identifier of the terminal device, wherein the first identifier of the terminal device is associated with radio access network (RAN) paging.

[0049] Since the first paging message may carry an identifier of the first multicast service, a terminal device corresponding to the first multicast service may be paged using the first paging message, whereby the terminal device attempts to enter an RRC connected state based on the first paging message. The terminal device that has entered the RRC connected state may receive data of the first multicast service. It can be seen that according to the solution provided in the embodiments of the present application, a terminal device in an RRC inactive state is enabled to enter the RRC connected state. A solution is provided for a terminal device in an RRC inactive state that cannot successfully or immediately receive data of the first multicast service.

[0050] Furthermore, when the first paging message carries an identifier of the first multicast service but does not carry an identifier of the first terminal device, or when the first paging message includes an identifier of the first multicast service and a first identifier of the first terminal device, the first identifier is an identifier associated with RAN paging. In this way, the terminal device can initiate an RRC connection resumption to attempt to enter an RRC connected state, thereby reducing the delay when the first terminal device enters an RRC connected state.

[0051] As shown in Figure 2, the communication method provided in the embodiments of the present application may be used in a wireless communication system, which may include a terminal device and a network device. The terminal device 11 in Figure 1 may be any terminal device in Figure 2 (e.g., the terminal device 111, the terminal device 112, or the terminal device 113 shown in Figure 2). The network device 12 in Figure 1 may be an access network device in Figure 2 (e.g., the base station 121 or the base station 122 in Figure 2), or alternatively, may be a core network device in Figure 2 (e.g., the core network device 123 or the core network device 124 in Figure 2). Hereinafter, a wireless communication system to which the embodiments of the present application are applicable will be described with reference to Figure 2.

[0052] It should be understood that the aforementioned wireless communication system is applicable to both low frequency scenarios (below 6G) and high frequency scenarios (above 6G). Application scenarios of the wireless communication system include, but are not limited to, long term evolution (LTE) systems, fifth generation systems, new radio (NR) communication systems, future evolved public land mobile network (PLMN) systems, etc. Application scenarios of the wireless communication system may also include a centralized unit (CU)-distributed unit (DU) architecture.

[0053] The terminal device shown above (e.g., terminal device 111, terminal device 112, or terminal device 113 shown in FIG. 2) may be a user equipment (UE), terminal, access terminal, terminal unit, terminal station, mobile station (MS), remote station, remote terminal, mobile terminal, wireless communication device, terminal agent, terminal device, etc. The terminal device may have wireless transceiver functionality and may communicate with (e.g., implement wireless communications with) one or more network devices in one or more communication systems and may receive network services provided by the network devices. The network device in this specification includes, but is not limited to, the network devices shown in FIG. 2 (e.g., base station 121, base station 122, core network device 123, or core network device 124 in FIG. 2).

[0054] The terminal device may be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA) device, a handheld device with wireless communication capabilities, a computing device, another processing device connected to a wireless modem, an in-vehicle device, a wearable device, a terminal device in a future 5G network, a terminal device in a future evolved PLMN network, etc.

[0055] In addition, the terminal device may be deployed on land, including indoor or outdoor deployment, or handheld or vehicle-mounted deployment. Alternatively, the terminal device may be deployed on water (e.g., on a ship), or in the air (e.g., on an aircraft, balloon, or satellite). Specifically, the terminal device may be a mobile phone, a tablet computer (pad), a computer with wireless transceiver functionality, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in telemedicine, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, etc. Alternatively, the terminal device may be a communication chip with a communication module, a vehicle with communication functionality, an in-vehicle device (e.g., an in-vehicle communication device or an in-vehicle communication chip), etc.

[0056] In the embodiment of the present application, the network device may be an access network device (also called an access network site) or a core network device, the descriptions of which are provided separately below.

[0057] In the first case, the network device may be an access network device (also called an access network site).

[0058] When the network device is an access network device, the network device may be further connected to a core network (CN) device. The access network device is a device providing network access functionality, such as a radio access network (RAN) or a base station. The network device may specifically include a base station (BS) (e.g., a RAN base station), or may include a base station and a radio resource management device configured to control the base station. The network device may further include a relay station (relay device), an access point, a base station in a future 5G network, a base station in a future evolved PLMN network, an NR base station, etc. The network device may be a wearable device or an in-vehicle device. Alternatively, the network device may be a communication chip having a communication module.

[0059] For example, a network device may be, but is not limited to, a next generation NodeB (gNodeB, gNB) in 5G, an evolved NodeB (eNB) in a long term evolution (LTE) system, a radio network controller (RNC), a radio controller in a cloud radio access network (CRAN) system, a base station controller (BSC), a home base station (e.g., a home evolved NodeB or home NodeB, HNB), a baseband unit (BBU), a transmission reception point (TRP), a transmission point (TP), a mobile switching center, a base transceiver station (BTS) in a global system for mobile communications (GSM) or code division multiple access (CDMA) network, a node base station (BTS) in a wideband code division multiple access (WCDMA) network, a base station (BSC) in a wideband code division multiple access (WCDMA) network, a base station (BSC) in a mobile radio access network (MCN) system, a base station (BSC) in a mobile radio access network (MCN), ... This includes a base station (NB), an evolved NB (eNB or eNodeB) in LTE, a base station device in a future 5G network, an access network device in a future evolved PLMN network, a wearable device, or an in-vehicle device.

[0060] In the second case, the network device may be a core network device.

[0061] A core network device may be configured to provide core network services for terminal devices accessing the network device. A core network device may correspond to different devices in different systems. For example, in 3G, a core network device may correspond to a serving general packet radio service (GPRS) support node (SGSN) and / or a gateway GPRS support node (GGSN). In 4G, a core network device may correspond to a mobility management entity (MME) and / or a serving gateway (S-GW). In 5G, a core network device may correspond to an access and mobility management function (AMF), a session management function (SMF), or a user plane function (UPF).

[0062] The system architecture shown in Figure 2 will be described using a 5G network as an example. As shown in Figure 2, an access network device (the access network device may also be referred to as a next generation radio access network (NG-RAN) node) may include a gNB and an ng-eNB. The gNB may be, for example, base station 121 in Figure 2, and the ng-eNB may be, for example, base station 122 in Figure 2. The gNB is connected to the ng-eNB through an Xn interface.

[0063] An access network device may be connected to a core network device through an NG interface. For example, an access network device may be connected to an AMF through an NG-C interface and to a UPF through an NG-U interface. The NG-C interface may also be referred to as a control plane interface between the NG-RAN and the 5GC. The NG-U interface may also be referred to as a user plane interface between the NG-RAN and the 5GC.

[0064] In the following, nouns and terms in the embodiments of the present application are explained and described.

[0065] 1. Paging

[0066] The purpose of paging is to Enabling the network to contact UEs in RRC_IDLE and RRC_INACTIVE states using paging messages; and notifying UEs in RRC_IDLE, RRC_INACTIVE, and RRC_CONNECTED states of system information changes and ETWS or CMAS indications using short message service; Paging messages may be transmitted on the PDSCH, and short message service may be transmitted directly on the PDCCH (ie, DCI).

[0067] RRC_ IDLE A UE in the CN state can receive paging control channel (PCH) triggered paging from the CN. ,PA UE in RRC_INACTIVE state monitors the RRC control channel (CCH) for RAN-triggered paging, and a UE in RRC_INACTIVE state also monitors the paging control channel for RAN-triggered paging. When the UE receives a RAN-initiated paging, it initiates the RRC connection resumption process and determines the resumption cause based on the value of the AI ​​(Access Identification) configured by higher layers. When a UE in RRC_INACTIVE state receives a CN-initiated paging, it changes to RRC_IDLE and notifies the NAS layer. This is sometimes called unicast associated paging.

[0068] For example, RAN paging may be understood as paging initiated by the RAN.

[0069] For example, CN paging may be understood as paging initiated by the CN.

[0070] A paging occasion in an embodiment of the present application may include, but is not limited to, one or more radio frames, subframes, slots, etc.

[0071] The time domain resource in the embodiment of the present application may be an interval, such as, but not limited to, a radio frame, a subframe, a slot, a symbol, or a mini-slot.

[0072] One DRX cycle may have one or more PFs, and each PF may have one or more paging occasions (POs).

[0073] From the perspective of monitoring paging by a terminal device, if discontinuous reception (DRX) is currently configured for a terminal device in an RRC idle or inactive state, the terminal device monitors one PO in each DRX cycle to save energy. One PO may include a group of PDCCH monitoring occasions. One paging frame (PF) may be a radio frame and may include one or more POs or the start of one or more POs.

[0074] Generally, for a terminal device in an RRC idle state or an RRC inactive state, the terminal device wakes up (i.e., monitors paging) once in the PO corresponding to the terminal device during each paging period and listens for paging messages and short message service (short message) scheduling information.

[0075] The downlink control information (DCI) corresponding to the paging message is scrambled using a paging radio network temporary identifier (P-RNTI).

[0076] Currently, the time domain location of a PO can be determined by the terminal device identifier (UE ID).

[0077] For example, PF can be obtained according to the following formula: (SFN+PF_offset)mod T =(T div N)*(UE_ID mod N)

[0078] The index (index(i_s)) of the PO is obtained according to the following formula: i_s = floor(UE_ID / N)mod Ns

[0079] i_s: The UE uses i_s to determine the PO of the PF corresponding to the UE.

[0080] T indicates the DRX period of the UE.

[0081] N indicates the number of paging frames in a DRX cycle.

[0082] Ns indicates the number of POs in a paging frame.

[0083] UE_ID is 5G-S-TMSI mod 1024, where mod indicates modulo operation. If the UE does not have 5G-S-TMSI, for example, when the UE is not registered in the network, the UE should use UE_ID=0.

[0084] The values ​​of N, Ns, and PF_offset may be broadcast by the network in the system information SIB 1.

[0085] T is the DRX period and may be determined according to the following rule: A terminal device in an RRC idle state and a terminal device in an RRC inactive state may use the shortest DRX period available.

[0086] A UE in RRC_IDLE state uses the shorter DRX cycle of (1) or (2), A UE in the RRC_INACTIVE state uses the shortest DRX cycle among (1), (2), and (3). (1) Default DRX period broadcast in system information (SIB 1) (2) A UE-specific DRX cycle negotiated between the UE and the core network. (3) A UE-specific DRX cycle transmitted to the UE by the network (e.g., radio access network).

[0087] 2. RRC connected state, RRC inactive state, or RRC idle state

[0088] There are three RRC connection states: RRC_connected, RRC_inactive, and RRC_idle.

[0089] When a terminal device accesses a network and sets up an RRC connection to a serving base station, the terminal device is in an RRC connected state, in which case the terminal device can successfully exchange data and signaling with the serving base station.

[0090] For a terminal device in an RRC idle state, the serving base station releases the context information of the terminal device, and it takes a long time for the terminal device to enter an RRC connected state from an RRC idle state.

[0091] The RRC inactive state is a state between the RRC connected state and the RRC idle state.

[0092] A terminal device in an RRC inactive state may initiate an RRC connection resumption (e.g., send an RRC connection resumption request message) to attempt to enter the RRC connected state. Lower latency may be implemented when a terminal device enters the RRC connected state from an RRC inactive state compared to the process of a terminal device entering the RRC connected state from an RRC idle state.

[0093] 3. Radio Access Network-based Notification Area (RAN-based notification area, RNA)

[0094] When a terminal device is switched from an RRC connected state to an RRC inactive state, the serving base station may configure an RNA for the terminal device, and the terminal device may move within the RNA without notifying the serving base station.

[0095] When the terminal device moves out of the RNA, an RNA update process is initiated. When the network has data to be sent to the terminal device, a paging process can be initiated in the RNA, which causes the terminal device to enter the RRC connected state from the RRC inactive state.

[0096] 4. Multicast and Unicast

[0097] The multicast service referred to in the embodiments of this application may be a multimedia broadcast multicast service (MBMS) in LTE or a multicast broadcast service (MBS) in new radio (NR) systems. MBS is introduced by 3GPP to effectively utilize mobile communication network resources. MBS provides a point-to-multipoint service in which a data source transmits data to multiple users in a mobile communication network, thereby implementing network resource sharing and improving resource utilization, especially for air interface resources. NR MBS supports multicast and broadcast.

[0098] In an embodiment of the present application, "multicast" may alternatively be the term "groupcast," for example. Correspondingly, a multicast service may alternatively be a groupcast service, and an identifier of a multicast service may alternatively be an identifier of a groupcast service.

[0099] It should be noted that the same service and / or the same content data may be provided simultaneously to all terminal devices within a geographic area, and a broadcast may be directed to all terminal devices within the area.

[0100] Through multicasting, the same service and / or the same content data may be provided simultaneously to a group of dedicated terminal devices (in other words, not all terminal devices within coverage are authorized to receive the data).

[0101] The multicast may be directed to a specific group of terminal devices, which may need to perform a "group joining process."

[0102] Correspondingly, unicasting can be understood as providing the same service and / or content data to one terminal device simultaneously, and when one piece of data needs to be transmitted to multiple devices, unicasting can be understood as the need to transmit this data separately to each device.

[0103] It should be noted that in this application, an identifier may include information, alternatively may be information, or may be understood as information, and is not necessarily limited to an identifier.

[0104] It should be noted that in this application, multicast service activation may include, alternatively be, or may be understood as, multicast session activation or MBS session activation.

[0105] It should be noted that in this application, a multicast service may include, or alternatively may be, or may be understood as, a multicast session, an MBS session, or an MBS service.

[0106] For example, unicast-related paging or unicast paging may include RAN paging and / or CN paging.

[0107] In the prior art, a multicast service has a corresponding multicast session. The multicast session has an activated state and a deactivated state. For a terminal device that has joined the multicast session, when the multicast session is deactivated and the terminal device does not have a unicast service, the terminal device may enter an RRC idle state or an RRC inactive state. When a multicast session is activated, the network device needs to send a multicast session activation notification to indicate to the terminal device to enter a connected state and receive data of the multicast service.

[0108] Currently, a network device may send a multicast activation notification (e.g., sometimes referred to as a multicast-related paging) by sending a paging message, and the paging message may include an identifier of the multicast service (the identifier of the multicast service may also be referred to as an identifier (ID) of the MBS). After the terminal device receives the paging message, the RRC Idle or inactiveA terminal device in the RRC idle state may initiate RRC connection resumption and enter the RRC connected state. In addition, control information corresponding to the paging message used to notify the multicast activation notification is also transmitted at the location of the UE's existing PO (e.g., the calculation-related content of the PO may be referred to as a unicast PO). This creates a new case, namely, a case in which one paging message may include both unicast-related paging and multicast-related paging for one terminal device. In this case, the processing performed by the terminal device after receiving the unicast-related paging may differ from the processing performed by the terminal device after receiving the multicast-related paging, so there is currently no effective method for determining the processing performed by the terminal device. For example, a terminal device enters the RRC idle state after receiving a CN paging, and the terminal device initiates RRC connection resumption after receiving a multicast-related paging. Because the processing performed by a terminal device that receives a CN paging differs from the processing performed by a terminal device that receives a multicast-related paging, the terminal device needs to determine the processing to be performed. For example, the terminal device initiates RRC connection resumption after receiving RAN paging, and the terminal device initiates RRC connection resumption after receiving multicast-related paging. If the terminal device's reception of the RAN paging corresponds to the terminal device's reception of the multicast-related paging and the RRC connection resumption cause determined by the terminal device is different, the terminal device needs to determine the processing to be performed.

[0109] In view of this, the embodiments of the present application provide a communication method to solve this problem.The following describes the solution provided in the present application based on the above content.

[0110] Based on the foregoing, Fig. 3a is a schematic flowchart example of a communication method according to an embodiment of the present application. The communication method shown in Fig. 3a may be applicable to the system architecture shown in Fig. 1 and / or Fig. 2. For example, the solution performed by the first terminal device in Fig. 3a may be performed by the terminal device 11 in Fig. 1, alternatively by a module or chip of the terminal device 11, alternatively by a terminal device (e.g., terminal device 111, terminal device 112, or terminal device 113) in Fig. 2, or alternatively by a module or chip of the terminal device (e.g., terminal device 111, terminal device 112, or terminal device 113) in Fig. 2. In another example, the solution performed by the fourth network device in FIG. 3a may be performed by network device 12 in FIG. 1, or alternatively, by a module or chip of network device 12, or alternatively, by a network device in FIG. 2 (e.g., access network device 121, access network device 122, core network device 123, or core network device 124), or alternatively, by a module or chip of a network device in FIG. 2 (e.g., access network device 121, access network device 122, core network device 123, or core network device 124).

[0111] It should be noted that the solutions in the present application are described using terminal devices and network devices as examples, but are not limited to being applicable only to terminal devices and network devices, and the solutions may alternatively be applicable to devices to which the solutions in the present application can be applied, and the terminal device may alternatively be a device, and the network device may alternatively be a device.

[0112] As shown in FIG. 3a, the method includes the following steps:

[0113] S301: A first terminal device receives a first paging message.

[0114] For example, in S301, the first terminal device may receive a first paging message from the fourth network device.

[0115] For example, the fourth network device may be an access network device.

[0116] In this embodiment of the present application, when a network device needs to page a first terminal device due to unicast, the network device may send a paging message to the first terminal device. In this case, the paging message needs to carry an identifier of the first terminal device. When a network device needs to page a first terminal device due to multicast (e.g., a first multicast service), the network device also needs to send a paging message to the first terminal device. In this case, the paging message may carry an identifier of the first multicast service. When a network device needs to page a first terminal device due to unicast and multicast (e.g., a first multicast service), the paging message sent by the network device to the first terminal device may carry both the identifier of the first terminal device and the identifier of the first multicast service.

[0117] In possible implementations, the first paging message may be used for any one or more of the following: to notify that a first multicast service is activated; to notify that a first multicast session is activated; to page a terminal device for the first multicast service; to page the first terminal device for the first multicast service; to page a terminal device (e.g., the first terminal device).

[0118] For example, at S301, the first terminal device may be in an RRC inactive state.

[0119] After step S301, the first terminal device may perform the following step S302 or S303.

[0120] S302: The first terminal device initiates an RRC connection resumption.

[0121] S303: The first terminal device enters an RRC idle state.

[0122] When the first condition is met, the first terminal device may perform step S302.

[0123] When the second condition is met, the first terminal device may perform step S303.

[0124] Based on the solution shown in FIG. 3a, after receiving the first paging message, the first terminal device may attempt to enter the RRC connected state in different manners under different conditions, thereby reducing the delay when the first terminal device enters the RRC connected state. For example, when the first paging message includes an identifier of the first multicast service and a second identifier of the first terminal device (condition 4), if the first terminal device first initiates RRC connection resumption after receiving the first paging message, and if the network device cannot acquire, confirm, or verify the UE context of the first terminal device, the first terminal device needs to fall back to RRC connection setup. However, the processing in this embodiment of the present application can enable the first terminal device to enter the RRC idle state after receiving the first paging message and attempt to enter the RRC connected state through RRC connection setup, thereby allowing the first terminal device to enter the RRC connected state more quickly. In addition, it should be noted that the "network device being unable to obtain or confirm the UE context of the first terminal device" may involve interaction between the network device and the terminal device, which may also take some time and result in delays.

[0125] In S302, "the first terminal device initiates an RRC connection resumption" may include, alternatively may be, or may be understood as, the first terminal device initiating an RRC connection resumption process.

[0126] For details regarding RRC connection resumption, please refer to section 5.3.13 (5.3.13 RRC connection resume) of "NR; Radio Resource Control (RRC); Protocol specification" in 3GPP TS 38.331. Details will not be described again here. Note that this application does not limit whether "the first terminal device initiates RRC connection resumption" is the same as RRC connection resumption in the prior art.

[0127] "The first terminal device enters the RRC idle state" may include, alternatively may be, or may be understood as, the first terminal device performing an action to enter the RRC idle state, or performing an action after the first terminal device has entered the RRC idle state.

[0128] For the content related to "the first terminal device performing an action upon entering an RRC idle state or performing an action after the first terminal device has entered an RRC idle state," please refer to section 5.3.11 (5.3.11 UE actions upon going to RRC_IDLE) of "NR; Radio Resource Control (RRC); Protocol specification" in 3GPP TS 38.331. Details will not be described again here. Please note that whether "the first terminal device has entered an RRC idle state" is the same as the action of the UE after entering an RRC idle state in the prior art.

[0129] Optionally, for step 303, the present application further includes that the release cause is "other."

[0130] In a possible implementation, the first condition may include any one of condition 1, condition 2, and condition 3.

[0131] Condition 1: The first paging message includes an identifier of the first multicast service, and the first paging message does not include an identifier of the first terminal device.

[0132] In this embodiment of the present application, the first paging message including the identifier of the first multicast service may mean that the identifier of the multicast service carried in the first paging message matches the identifier of the first multicast service.

[0133] In this embodiment of the present application, the first paging message not including the first identifier of the first terminal device may mean that the identifiers of all terminal devices carried in the first paging message do not match the first identifier of the first terminal device.

[0134] Condition 2: The first paging message includes an identifier of the first multicast service and a first identifier of the first terminal device.

[0135] In this embodiment of the present application, the first paging message including the first identifier of the first terminal device may mean that the identifier of the terminal device carried in the first paging message matches the first identifier of the first terminal device.

[0136] Condition 3: The first paging message includes a first identifier of the first terminal device, and the first paging message does not include an identifier of the first multicast service.

[0137] In this embodiment of the present application, the first paging message not including the identifier of the first multicast service may mean that the identifiers of all multicast services carried in the first paging message do not match the identifier of the first multicast service.

[0138] For example, when the first paging message includes the first identifier of the first terminal device but does not include the identifier of the first multicast service, this means that the network device pages the first terminal device due to unicast. In this case, if the identifier of the terminal device included in the first paging message matches the first identifier of the first terminal device, this indicates that the paging is RAN paging, and the first terminal device may perform S302.

[0139] In this implementation, the first paging message is Multicast When the first paging message carries an identifier of the service but not an identifier of the terminal device, or when the first paging message includes an identifier of the first multicast service and the first identifier, or when the first paging message carries only the first identifier, the first identifier is an identifier associated with RAN paging. In this case, the terminal device may initiate RRC connection resumption to attempt to enter an RRC connected state, which can accelerate the entering of the RRC connected state by the terminal device and can reduce delay in resuming the RRC connected state by the terminal device.

[0140] In addition, when the first paging message includes an identifier of the first multicast service and the first identifier, this indicates that the network device pages the first terminal device due to unicast and multicast. In this case, the terminal device may initiate RRC connection resumption to attempt to enter an RRC connected state. Therefore, for a scenario in which the network device pages the first terminal device due to unicast and multicast, a terminal device-side processing solution is provided, which can accelerate the terminal device's entry into the RRC connected state and reduce the delay in resuming the RRC connected state by the terminal device.

[0141] In a possible implementation, the second condition may include condition 4 or condition 5.

[0142] Condition 4: The first paging message includes an identifier of the first multicast service and a second identifier of the first terminal device.

[0143] Condition 5: The first paging message includes a second identifier of the first terminal device.

[0144] For example, when a first paging message includes an identifier of a first terminal device and the identifier of the first terminal device is a second identifier, this may indicate that the paging is a CN paging, or the paging may be understood as paging initiated by the CN.

[0145] When the first paging message includes the second identifier of the first terminal device but does not include the identifier of the first multicast service, this indicates that the network device pages the first terminal device by unicast rather than multicast. In this case, if the identifier of the terminal device included in the first paging message matches the second identifier of the first terminal device, this indicates that the paging is CN paging, and the first terminal device may perform S303.

[0146] Since the first paging message includes the identifier of the first multicast service and the second identifier of the first terminal device, it indicates that the network device pages the first terminal device due to unicast and multicast. In this case, how to determine by the first terminal device becomes an urgent problem to be solved, especially for special scenarios.

[0147] In a possible implementation, when the first paging message includes an identifier of the first multicast service, the first terminal device is required to initiate an RRC connection resumption after receiving the first paging message. When the first paging message includes a second identifier of the first terminal device, the first terminal device is required to enter an RRC idle state.

[0148] In the above-mentioned special scenario, the first paging message includes an identifier of the first multicast service and a second identifier of the first terminal device, so the first terminal device cannot respond to the first paging message.

[0149] However, the solution provided in the embodiment of the present application can further solve the problem in the above-mentioned special scenario. In this embodiment of the present application, when the first paging message includes the identifier of the first multicast service and the second identifier of the first terminal device, the first terminal device performs S303. Therefore, the problem that the first terminal device cannot respond to the first paging message can be solved.

[0150] In another aspect, when a second condition is met, a terminal device in an RRC inactive state may enter an RRC connected state from an RRC idle state. For example, after the terminal device enters the RRC idle state, the terminal device may transmit a second message. The second message is used to request an RRC connection to be set up. In this way, the terminal device in an RRC inactive state may select a manner of entering the RRC connected state based on the content carried in the received first paging message. In addition, entering the RRC idle state when the second condition is met may better match the manner of entering the RRC connected state by the terminal device in the unicast case. This reduces the delay in entering the RRC connected state by the terminal device in this case.

[0151] An identifier of the first multicast service is associated with the first multicast service.

[0152] For example, when the first terminal device determines that the multicast service identified by the multicast service identifier carried in the first paging message is a multicast service that the first terminal device will join (e.g., the first terminal device may subscribe to a multicast service), or when the first terminal device determines that the multicast service identified by the multicast service identifier carried in the first paging message is a service that the first terminal device is interested in and / or receiving, the first terminal device may perform S302 (in yet another possible implementation, the first terminal device may perform S303).

[0153] The first multicast service may include a multicast service that the first terminal device joins. It may be understood that the first multicast service may include one or more multicast services.

[0154] For example, the identifier of the multicast service may include any one or more of the following: a temporary mobile group identity (TMGI), an MBS service ID, a multicast service identifier, a wireless network temporary identifier used to schedule the MBS service or the multicast service (e.g., a group radio network temporary identifier (G-RNTI) and G-CS-RNTI), a multicast session identifier, an MBS session ID, a protocol data unit (PDU) session ID used to transmit the multicast service, etc.

[0155] It should be noted that the identifier of the first multicast service may include, or alternatively may be, or may be understood as, information about the first multicast service.

[0156] It should be noted that a multicast service may include, or alternatively may be, or may be understood as, a multicast session, an MBS session, or an MBS service.

[0157] It should be noted that multicast may include, or alternatively may be, or may be understood as, MBS, broadcast, or groupcast.

[0158] For example, the identifier of the first terminal device may include a first identifier of the first terminal device and a second identifier of the first terminal device.

[0159] For example, a first identifier of a first terminal device is associated with RAN paging.

[0160] For example, when the first paging message includes an identifier of the first terminal device and the identifier of the first terminal device is the first identifier, it may indicate that the paging is RAN paging, or that the paging may be understood as paging initiated by the RAN.

[0161] For example, the third message sent by the fifth network device to the first terminal device may include information about a first identifier of the first terminal device.

[0162] The information about the first identifier of the first terminal device may include some or all of the information about the first identifier of the first terminal device. For example, the information about the first identifier of the first terminal device may be some bits of the first identifier of the first terminal device or all bits of the first identifier of the first terminal device.

[0163] The third message indicates or commands the release of the RRC connection or the suspension (eg, suspension) of the RRC connection.

[0164] For example, the third message may be a RRCRelease message.

[0165] For example, the fourth message sent by the first terminal device to the sixth network device may include information about a first identifier of the first terminal device.

[0166] The fourth message requests that an interrupted (eg, suspended) RRC connection be resumed or that an RNA update be performed.

[0167] For example, the fourth message may be a RRCResumeRequest1 message.

[0168] It should be noted that any one or more of the fourth network device, the fifth network device, and the sixth network device may be the same network device or different network devices.

[0169] For example, the fifth network device is an access network device.

[0170] For example, the sixth network device is an access network device.

[0171] For example, the size of the first identifier of the first terminal device may be 40 bits.

[0172] For example, the first identifier of the first terminal device is used to identify a suspended (e.g., suspended) UE context of the first terminal device, or is used to identify a UE context of the first terminal device.

[0173] For example, the first identifier of the first terminal device may include any one or more of the following: a complete I-RNTI, a complete I-RNTI of the first terminal device, a complete I-RNTI stored in the first terminal device, an I-RNTI (inactive RNTI), an I-RNTI of the first terminal device, and an I-RNTI stored in the first terminal device.

[0174] For example, the second identifier of the first terminal device is associated with the CN paging.

[0175] For example, the second identifier of the first terminal device may be provided or assigned by an upper layer of the first terminal device (e.g., a NAS layer of the first terminal device). Alternatively, the second identifier of the first terminal device may be provided or assigned to the first terminal device (e.g., an AS layer of the first terminal device) by an upper layer of the first terminal device (e.g., a NAS layer of the first terminal device).

[0176] For example, the second identifier of the first terminal device may be provided to the first terminal device by the core network device. Note that the second identifier of the first terminal device may be transmitted to the first terminal device by the core network device, or may be transmitted to the first terminal device by the core network device using the access network device. This is not limited in the present application.

[0177] For example, the second identifier of the first terminal device may be used to identify (eg, uniquely identify) the first terminal device in a tracking area.

[0178] For example, the fifth message sent by the first terminal device to the seventh network device may include information about a second identifier of the first terminal device.

[0179] The information about the second identifier of the first terminal device may include some or all of the information about the second identifier of the first terminal device. For example, the information about the second identifier of the first terminal device may be some bits of the second identifier of the first terminal device or all bits of the second identifier of the first terminal device.

[0180] The fifth message is used to request to set up an RRC connection.

[0181] For example, the fifth message may be an RRCSetupRequest message.

[0182] For example, the sixth message sent by the first terminal device to the seventh network device may include information about a second identifier of the first terminal device.

[0183] The sixth message is used to confirm that the RRC connection setup has been completed successfully.

[0184] For example, the sixth message may be an RRCSetupComplete message.

[0185] For example, the second identifier of the first terminal device may include any one or more of the following: a 5G S-temporary mobile subscription identifier (5G-S-TMSI), a system architecture evolution temporary mobile station identifier (S-TMSI), an international mobile subscriber identity (IMSI), and an ng-5G-S-TMSI.

[0186] For example, condition 1 may include, or alternatively may be, or may be understood as, that the first paging message includes an identifier of the first multicast service and that the first paging message does not include a first identifier of the first terminal device and a second identifier of the first terminal device.

[0187] For example, condition 2 may include, or alternatively may be, or may be understood as, that the first paging message includes an identifier of the first multicast service and a first identifier of the first terminal device, and that the first paging message does not include a second identifier of the first terminal device.

[0188] For example, condition 3 may include, or alternatively may be, or may be understood as, that the first paging message includes a first identifier of the first terminal device and that the first paging message does not include an identifier of the first multicast service and a second identifier of the first terminal device.

[0189] For example, condition 4 may include, or alternatively may be, or may be understood as, that the first paging message includes an identifier of the first multicast service and a second identifier of the first terminal device, and that the first paging message does not include the first identifier of the first terminal device.

[0190] For example, condition 5 may include, or alternatively may be, or may be understood as, that the first paging message includes a second identifier of the first terminal device and that the first paging message does not include an identifier of the first multicast service and a first identifier of the first terminal device.

[0191] For example, "the first condition is met" may include, alternatively be, or be understood as, that the third condition is not met and the first paging message includes an identifier of the first multicast service.

[0192] The third condition includes that the first paging message includes a second identifier of the first terminal device.

[0193] For example, the third condition may include, or alternatively may be, or may be understood as, that the first paging message includes a second identifier of the first terminal device and that the first paging message does not include a first identifier of the first terminal device.

[0194] It should be noted that in this embodiment of the present application, with respect to "the first paging message includes an identifier of the first multicast service," the first paging message may further include an identifier of another multicast service, or the first paging message may not include an identifier of another multicast service, which is not limited in the present application.

[0195] In this embodiment of the present application, with regard to "the first paging message does not include an identifier of the first multicast service," it should be noted that the first paging message may include an identifier of another multicast service, or the first paging message may not include an identifier of another multicast service. This is not limited in the present application. In possible cases, "the first paging message does not include an identifier of the first multicast service" may include, alternatively mean, or be understood as, that the first paging message does not include an identifier of a multicast service, or that the first paging message does not include an identifier of any multicast service.

[0196] In this embodiment of the present application, with regard to "the first paging message does not include an identifier of the first terminal device," it should be noted that the first paging message may include an identifier of another terminal device, or the first paging message may not include an identifier of another terminal device. This is not limited in the present application. In possible cases, "the first paging message does not include an identifier of the first terminal device" may include, alternatively, or be understood as, the first paging message not including an identifier of a terminal device, or the first paging message not including any identifier of any terminal device.

[0197] Optionally, after step S302, the first terminal device may perform the following step S304. Alternatively, optionally, "the first terminal device initiates RRC connection resumption" may include the first terminal device sending a first message.

[0198] S304: The first terminal device sends a first message.

[0199] For example, a first terminal device sends a first message to a network device.

[0200] The first message is used to request that the RRC connection be resumed.

[0201] For example, the first message may be an RRC message, such as an RRCResumeRequest message or an RRCResumeRequest1 message.

[0202] It should be noted that after initiating the RRC connection resumption, the first terminal device may or may not send the first message, which is not limited in the present application.

[0203] It should be noted that the order of step S302 and step S304 is not limited in the present application.

[0204] For example, the first message may include information about a first identifier of the first terminal device.

[0205] It should be noted that the first message and the fourth message may be the same message or may be different, which is not a limitation in this application.

[0206] Optionally, after step S303, the first terminal device may perform the following step S305. Alternatively, optionally, "the first terminal device enters an RRC idle state" may include the first terminal device sending a second message.

[0207] S305: The first terminal device sends a second message.

[0208] The second message is used to request to set up an RRC connection.

[0209] For example, the second message may be an RRC message, such as an RRCSetupRequest message.

[0210] It should be noted that after entering the RRC idle state, the first terminal device may or may not send the second message, which is not limited in this application.

[0211] It should be noted that the order of step S303 and step S305 is not limited in this application.

[0212] For example, the second message may include information about a second identifier of the first terminal device.

[0213] Optionally, the application further includes the first terminal device notifying an upper layer of the first terminal device (for example, the upper layer is a NAS layer).

[0214] The first terminal device notifying the upper layer of the first terminal device may include any one or more of the following:

[0215] When the first paging message includes a second identifier of the first terminal device, the first terminal device forwards the second identifier of the first terminal device included in the first paging message to an upper layer of the first terminal device; If the first paging message includes an access type, the first terminal device forwards the access type to an upper layer, and forwards the access type (if any) to an upper layer of the first terminal device; and If the first paging message includes an identifier of the first multicast service, the first terminal device forwards the identifier of the first multicast service to an upper layer of the first terminal device.

[0216] Optionally, the application further includes: the first terminal device performs the following step S306.

[0217] S306: The first terminal device determines a first RRC connection resumption cause.

[0218] It should be noted that step S306 may be performed before step S304. The order is not limited in this application. In this manner, the first RRC connection resumption cause may be carried in the first message for transmission, or the first RRC connection resumption cause and the first message may be transmitted separately. In yet another possible implementation, step S306 may alternatively be performed after S304. In this manner, the first RRC connection resumption cause and the first message may be transmitted separately. In FIG. 3a, S306 is shown before S304.

[0219] The first terminal device determining the first RRC connection resumption cause may include, alternatively may be, or may be understood as, the first terminal device setting the first RRC connection resumption cause.

[0220] For example, the first message may include a first RRC connection resumption cause.

[0221] The first terminal device's determining the first RRC connection resumption cause includes any one or more of solution d1, solution d2, solution d3, and solution d4.

[0222] Solution d1: The first terminal device determines a first RRC connection resumption cause according to a first policy.

[0223] In a possible implementation, the first policy may include first configuration information.

[0224] The first configuration information includes an RRC connection resumption cause corresponding to unicast, an access identity (AI), or an access identity and an RRC connection resumption cause corresponding to unicast.

[0225] In solution d1, the access identification may include, or alternatively may be, or may be understood as, an access identification corresponding to a unicast.

[0226] The access identification may alternatively be referred to as an access identifier.

[0227] In another possible implementation, the first policy may include a rule for determining or setting an RRC connection resumption cause corresponding to unicast.

[0228] In another possible implementation, the first policy may include first configuration information and a rule for determining or setting an RRC connection resumption cause corresponding to unicast.

[0229] For example, the first policy may include RRC connection resumption causes corresponding to unicast, and the first terminal device may select one of the RRC connection resumption causes corresponding to unicast included in the first policy as the first RRC connection resumption cause.

[0230] In another example, the first policy includes an access identification, or the first policy includes an access identification and an RRC connection resumption cause corresponding to unicast, and the first terminal device may determine one RRC connection resumption cause as the first RRC connection resumption cause based on the access identification included in the first policy.

[0231] In another example, the first policy includes an access identification, or the first policy includes an access identification and an RRC connection resumption cause corresponding to unicast. The first terminal device may determine a target access identification based on the access identification included in the first policy, and then use the RRC connection resumption cause corresponding to the target access identification as the first RRC connection resumption cause according to the correspondence between the access identification and the RRC connection resumption cause.

[0232] In another example, the first policy includes a rule for determining or setting an RRC connection resumption cause corresponding to unicast, and the rule for determining or setting an RRC connection resumption cause corresponding to unicast includes a correspondence relationship between an access identification and an RRC connection resumption cause. The first terminal device determines a target access identification, and then uses the RRC connection resumption cause corresponding to the target access identification as the first RRC connection resumption cause according to the correspondence relationship between the access identification and the RRC connection resumption cause included in the first policy.

[0233] The RRC connection resumption cause corresponding to unicast may be understood as follows: The RRC connection resumption cause corresponding to unicast is applicable when the first paging message includes a first identifier of the first terminal device but does not include an identifier of the first multicast service. Specifically, when the first paging message includes a first identifier of the first terminal device but does not include an identifier of the first multicast service, the first terminal device may alternatively determine the RRC connection resumption cause based on the RRC connection resumption causes corresponding to unicast, in other words, may determine one of the RRC connection resumption causes corresponding to unicast as the RRC connection resumption cause.

[0234] However, in this embodiment of the present application, in a possible implementation, when the first paging message includes a first identifier of the first terminal device and an identifier of the first multicast service, the first terminal device may alternatively determine the RRC connection resumption cause according to the first policy, in other words, may determine one of the RRC connection resumption causes corresponding to unicast included in the first policy as the first RRC connection resumption cause. It may be understood that when the first paging message includes an identifier of the first multicast service and the first identifier of the first terminal device, the first terminal device may reuse or use an RRC connection resumption cause corresponding to unicast to determine the first RRC connection resumption cause.

[0235] The RRC connection resumption cause for unicast is multimedia priority service (multimedia priority service, mps )-PriorityAccess(PriorityAccess), mission critical service(mission critical service, mcs )-PriorityAccess, highPriorityAccess(highPriorityAccess), or mobile terminated(mobile terminated, mt )-Access.

[0236] Optionally, in a possible understanding, the priorities of mps-PriorityAccess, mcs-PriorityAccess, highPriorityAccess, and mt-Access are in descending order.

[0237] In a possible implementation, the RRC connection resumption cause corresponding to unicast may be specified in the protocol or may be pre-configured or configured for the first terminal device by the network device.

[0238] In a possible implementation, in solution d1, the first terminal device may determine the first RRC connection resumption cause based on the access identification.

[0239] In a possible implementation, the access identification may be specified in the protocol or may be pre-configured or configured for the first terminal device by the network device.

[0240] For example, the access identification may include, or alternatively may be, or may be understood as, an access identification configured by an upper layer of the first terminal device.

[0241] The upper layer of the first terminal device may include, alternatively be, or be understood as, the NAS layer of the first terminal device.

[0242] "The first terminal device may determine the RRC connection resumption cause based on the access identification" may include, alternatively may be, or may be understood as, the first terminal device (e.g., the AS layer of the first terminal device) may determine the RRC connection resumption cause based on the access identification configured by a higher layer of the first terminal device.

[0243] The rule for determining or setting an RRC connection resumption cause corresponding to unicast may be understood as follows: The rule for determining or setting an RRC connection resumption cause corresponding to unicast is applicable when the first paging message includes a first identifier of the first terminal device but does not include an identifier of the first multicast service. Specifically, when the first paging message includes a first identifier of the first terminal device but does not include an identifier of the first multicast service, the first terminal device may alternatively determine the RRC connection resumption cause based on the rule for determining or setting an RRC connection resumption cause corresponding to unicast.

[0244] However, in this embodiment of the present application, in a possible implementation, when the first paging information includes a first identifier of the first terminal device and an identifier of the first multicast service, the first terminal device may alternatively determine the RRC connection resumption cause according to the first policy. It may be understood that when the first paging message includes an identifier of the first multicast service and a first identifier of the first terminal device, the first terminal device may determine the first RRC connection resumption cause by reusing or using the rule for determining or setting the RRC connection resumption cause corresponding to unicast.

[0245] It should be noted that the rules for determining or setting the RRC connection resumption cause corresponding to unicast may be specified in a protocol, or may be pre-configured or configured for the first terminal device by the network device. The specific rules are not limited in this application.

[0246] In a possible implementation, the first terminal device determining a first RRC connection resumption cause according to the first policy comprises: (1) when Access Identification 1 is configured by an upper layer of the first terminal device, setting a first RRC connection resumption cause to mps-PriorityAccess; (2) setting the first RRC connection resumption cause to mcs-PriorityAccess when access identification 1 is not configured by the upper layer of the first terminal device and access identification 2 is configured by the upper layer of the first terminal device; (3) setting the first RRC connection resumption cause to highPriorityAccess when Access Identification 1 and Access Identification 2 are not configured by the upper layer of the first terminal device and one or more of Access Identification 11 to Access Identification 15 are configured by the upper layer of the first terminal device; or (4) Setting the first RRC connection resumption cause to mt-Access when access identification 1, access identification 2, and access identification 11 to access identification 15 are not configured by the upper layer of the first terminal device. may include any one or more of:

[0247] In yet another possible implementation, the first policy may include multiple RRC connection resumption causes, and the first terminal device may select the RRC connection resumption cause with the highest priority from the multiple RRC connection resumption causes as the RRC connection resumption cause. For example, the multiple RRC connection resumption causes included in the first policy may include mps-PriorityAccess and mps-PriorityAccess, and mps-PriorityAccess has the highest priority. When the first paging message includes an identifier of the first multicast service and a first identifier of the first terminal device, the first terminal device may set the RRC connection resumption cause to mps-PriorityAccess.

[0248] In yet another possible implementation, when the first paging message includes an identifier of the first multicast service and a first identifier of the first terminal device, the first terminal device sets the RRC connection resumption cause to mt-Access, where mt-Access is the RRC connection resumption cause of the first policy.

[0249] It should be noted that how to determine the first RRC connection resumption cause according to the first policy is not limited in this application.

[0250] Solution d2: The first terminal device determines the first RRC connection resumption cause according to the second policy.

[0251] In a possible implementation, the second policy may include second configuration information.

[0252] The second configuration information includes an RRC connection resumption cause corresponding to multicast, an access identity (AI), or an access identity and an RRC connection resumption cause corresponding to multicast.

[0253] In solution d2, the access identification may include, or alternatively may be, or may be understood as, an access identification corresponding to multicast.

[0254] In another possible implementation, the second policy may include rules for determining or setting an RRC connection resumption cause corresponding to multicast.

[0255] In another possible implementation, the second policy may include second configuration information and rules for determining or setting an RRC connection resumption cause corresponding to multicast.

[0256] For example, the second policy may include RRC connection resumption causes corresponding to multicast, and the first terminal device may select one of the RRC connection resumption causes corresponding to multicast included in the second policy as the first RRC connection resumption cause.

[0257] In another example, the second policy includes an access identification corresponding to multicast, or the second policy includes an access identification corresponding to multicast and an RRC connection resumption cause corresponding to multicast, and the first terminal device may determine one RRC connection resumption cause as the first RRC connection resumption cause based on the access identification included in the second policy.

[0258] In another example, the second policy includes an access identification corresponding to multicast, or the second policy includes an access identification corresponding to multicast and an RRC connection resumption cause corresponding to multicast. The first terminal device may determine a target access identification based on the access identification included in the second policy, and then use the RRC connection resumption cause corresponding to the target access identification as the first RRC connection resumption cause according to the correspondence between the access identification and the RRC connection resumption cause.

[0259] In another example, the second policy includes a rule for determining or setting an RRC connection resumption cause corresponding to multicast, and the rule for determining or setting an RRC connection resumption cause corresponding to multicast includes a correspondence relationship between an access identification and an RRC connection resumption cause. The first terminal device determines a target access identification, and then uses the RRC connection resumption cause corresponding to the target access identification as the first RRC connection resumption cause according to the correspondence relationship between the access identification and the RRC connection resumption cause included in the second policy.

[0260] In a possible implementation, the first terminal device may determine the RRC connection resumption cause based on an access identification corresponding to multicast.

[0261] In a possible implementation, the access identification corresponding to the multicast may be specified in the protocol or may be pre-configured or configured for the first terminal device by the network device.

[0262] For example, an access identification corresponding to a multicast may include, or alternatively may be, or may be understood as, an access identification corresponding to a multicast configured by an upper layer of the first terminal device.

[0263] The upper layer of the first terminal device may include, alternatively be, or be understood as, the NAS layer of the first terminal device.

[0264] "The first terminal device may determine the RRC connection resumption cause based on an access identification corresponding to the multicast" may include, alternatively may be, or may be understood as, the first terminal device (e.g., the AS layer of the first terminal device) may determine the RRC connection resumption cause based on an access identification corresponding to the multicast configured by a higher layer of the first terminal device.

[0265] The rule for determining or setting an RRC connection resumption cause corresponding to multicast may be understood as follows: The rule for determining or setting an RRC connection resumption cause corresponding to multicast is applicable when the first paging information includes an identifier of the first multicast service but does not include an identifier of the first terminal device. Specifically, when the first paging information includes an identifier of the first multicast service but does not include an identifier of the first terminal device, the first terminal device may alternatively determine an RRC connection resumption cause based on the rule for determining or setting an RRC connection resumption cause corresponding to multicast.

[0266] However, in this embodiment of the present application, in a possible implementation, when the first paging information includes a first identifier of the first terminal device and an identifier of the first multicast service, the first terminal device may alternatively determine the RRC connection resumption cause according to the second policy. It may also be understood that when the first paging message includes an identifier of the first multicast service and a first identifier of the first terminal device, the first terminal device may determine the first RRC connection resumption cause by reusing or using the rule for determining or setting the RRC connection resumption cause corresponding to multicast.

[0267] It should be noted that the rules for determining or setting the RRC connection resumption cause corresponding to multicast may be specified in a protocol, or may be pre-configured or configured for the first terminal device by the network device. The specific rules are not limited in this application.

[0268] The RRC connection resumption causes corresponding to multicast may include any one or more of mps-PriorityAccess, mcs-PriorityAccess, highPriorityAccess, mt-Access, or MBS access (or multicast access).

[0269] For example, the RRC connection resumption cause corresponding to multicast includes mt-Access. For example, when the first paging information includes an identifier of the first multicast service and a first identifier of the first terminal device, the first terminal device sets the first RRC connection resumption cause to mt-Access.

[0270] Optionally, in a possible understanding, the priorities of mps-PriorityAccess, mcs-PriorityAccess, highPriorityAccess, multicastAccess, and mt-Access are in descending order.

[0271] In a possible implementation, the RRC connection resumption cause corresponding to multicast may be specified in the protocol or may be pre-configured or configured for the first terminal device by the network device.

[0272] In a possible implementation, the first terminal device determining the first RRC connection resumption cause according to the second policy includes: (1) when Access Identification 1 is configured by an upper layer of the first terminal device, setting a first RRC connection resumption cause to mps-PriorityAccess; (2) setting the first RRC connection resumption cause to mcs-PriorityAccess when access identification 1 is not configured by the upper layer of the first terminal device and access identification 2 is configured by the upper layer of the first terminal device; (3) setting the first RRC connection resumption cause to highPriorityAccess when Access Identification 1 and Access Identification 2 are not configured by the upper layer of the first terminal device and one or more of Access Identification 11 to Access Identification 15 are configured by the upper layer of the first terminal device; or (4) setting the first RRC connection resumption cause to multicast access when access identification 1, access identification 2, and access identification 11 to access identification 15 are not configured by an upper layer of the first terminal device; may include any one or more of:

[0273] In yet another possible implementation, the second policy may include multiple RRC connection resumption causes, and the first terminal device may select the RRC connection resumption cause with the highest priority from the multiple RRC connection resumption causes as the RRC connection resumption cause. For example, the multiple RRC connection resumption causes included in the second policy may include mps-PriorityAccess and mps-PriorityAccess, and mps-PriorityAccess has the highest priority. When the first paging message includes an identifier of the first multicast service and a first identifier of the first terminal device, the first terminal device may set the RRC connection resumption cause to mps-PriorityAccess.

[0274] In yet another possible implementation, when the first paging message includes an identifier of the first multicast service and a first identifier of the first terminal device, the first terminal device sets the RRC connection resumption cause to mt-Access, where mt-Access is the RRC connection resumption cause of the second policy.

[0275] In yet another possible implementation, the second policy may include multiple RRC connection resumption causes, and the first terminal device may select the RRC connection resumption cause with the highest priority from the multiple RRC connection resumption causes as the RRC connection resumption cause. For example, the multiple RRC connection resumption causes included in the second policy may include mps-PriorityAccess and mps-PriorityAccess, and mps-PriorityAccess has the highest priority. When the first paging message includes an identifier of the first multicast service and a first identifier of the first terminal device, the first terminal device may set the RRC connection resumption cause to mps-PriorityAccess.

[0276] It should be noted that in a possible implementation, the first policy and the second policy may be different.

[0277] It should be noted that the rules for determining or setting an RRC connection resumption cause corresponding to unicast may be different or the same as the rules for determining or setting an RRC connection resumption cause corresponding to multicast, which is not a limitation in this application.

[0278] It should be noted that the RRC connection resumption cause corresponding to unicast may be different or the same as the RRC connection resumption cause corresponding to multicast, which is not a limitation in this application.

[0279] It should be noted that the access identification may be different or the same as the access identification corresponding to the multicast, which is not a limitation in this application.

[0280] It should be noted that how to determine the first RRC connection resumption cause according to the second policy is not limited in this application.

[0281] Solution d3: The first terminal device determines a first RRC connection resumption cause according to the first policy and the second policy.

[0282] In a possible implementation, the first terminal device determines a second RRC connection resumption cause according to a first policy, the first terminal device determines a third RRC connection resumption cause according to a second policy, and the first terminal device determines one of the second RRC connection resumption cause and the third RRC connection resumption cause as the first RRC connection resumption cause.

[0283] For example, the first terminal device may determine the RRC connection resumption cause with the highest priority from the second RRC connection resumption cause and the third RRC connection resumption cause as the first RRC connection resumption cause. Note that how to select either the second RRC connection resumption cause or the third RRC connection resumption cause as the first RRC connection resumption cause is not limited in this application.

[0284] For content related to "The first terminal device determines the second RRC connection resumption cause according to the first policy," please refer to content related to "The first terminal device determines the first RRC connection resumption cause according to the first policy." Details will not be described again here.

[0285] For details related to "The first terminal device determines the third RRC connection resumption cause according to the second policy," please refer to details related to "The first terminal device determines the first RRC connection resumption cause according to the second policy." Details will not be described again here.

[0286] For solution d3, it can be understood that one RRC connection resumption cause needs to be determined based on solution d1, another RRC connection resumption cause also needs to be determined based on solution d2, and one of the two RRC connection resumption causes is determined as the first RRC connection resumption cause.

[0287] Solution d4: The first terminal device determines the first RRC connection resumption cause according to the third policy.

[0288] In a possible implementation, the third policy may include third configuration information.

[0289] The third configuration information includes an RRC connection resumption cause and access identification corresponding to unicast and multicast, or an RRC connection resumption cause and access identification corresponding to unicast and multicast.

[0290] In solution d4, the access identification may include, or alternatively may be, or may be understood as, an access identification corresponding to unicast and multicast.

[0291] In another possible implementation, the third policy may include rules for determining or setting RRC connection resumption causes corresponding to unicast and multicast.

[0292] In another possible implementation, the first policy may include third configuration information and rules for determining or setting RRC connection resumption causes corresponding to unicast and multicast.

[0293] For example, the third policy includes RRC connection resumption causes corresponding to unicast and multicast, and the first terminal device may select one of the RRC connection resumption causes corresponding to unicast and multicast included in the third policy as the first RRC connection resumption cause.

[0294] In another example, the third policy includes access identities corresponding to unicast and multicast. The first terminal device may determine a target access identity based on the access identities included in the third policy, and then use the RRC connection resumption cause corresponding to the target access identity as the first RRC connection resumption cause according to the correspondence between the access identities and the RRC connection resumption causes.

[0295] In another example, the third policy includes rules for determining or setting RRC connection resumption causes corresponding to unicast and multicast, and the rules for determining or setting RRC connection resumption causes corresponding to unicast and multicast include a correspondence relationship between access identification and RRC connection resumption causes. The first terminal device determines a target access identification, and then uses the RRC connection resumption cause corresponding to the target access identification as the first RRC connection resumption cause according to the correspondence relationship between the access identification and the RRC connection resumption cause included in the third policy.

[0296] The RRC connection resumption cause corresponding to unicast and multicast may be understood as follows: The RRC connection resumption cause corresponding to unicast and multicast is applicable when the first paging message includes a first identifier of the first terminal device and an identifier of the first multicast service. Specifically, when the first paging message includes a first identifier of the first terminal device and an identifier of the first multicast service, the first terminal device may alternatively determine the RRC connection resumption cause based on the RRC connection resumption causes corresponding to unicast and multicast, in other words, may determine one of the RRC connection resumption causes corresponding to unicast and multicast as the RRC connection resumption cause.

[0297] However, in this embodiment of the present application, in a possible implementation, when the first paging information includes a first identifier of the first terminal device and an identifier of the first multicast service, the first terminal device may alternatively determine the RRC connection resumption cause according to the third policy, in other words, may determine one of the RRC connection resumption causes corresponding to unicast and multicast included in the third policy as the first RRC connection resumption cause.

[0298] The RRC connection resumption causes corresponding to unicast and multicast may include any one or more of mps-PriorityAccess, mcs-PriorityAccess, highPriorityAccess, mt-Access, or unicast and multicast access.

[0299] Optionally, in a possible understanding, the priorities of mps-PriorityAccess, mcs-PriorityAccess, highPriorityAccess, unicast and multicast access, and mt-Access are in descending order.

[0300] In a possible implementation, the RRC connection resumption causes corresponding to unicast and multicast may be specified in the protocol or may be pre-configured or configured for the first terminal device by the network device.

[0301] In a possible implementation, in solution d4, the first terminal device may determine the RRC connection resumption cause based on the access identification.

[0302] In a possible implementation, the access identification may be specified in the protocol or may be pre-configured or configured for the first terminal device by the network device.

[0303] For example, the access identification may include, or alternatively may be, or may be understood as, an access identification configured by an upper layer of the first terminal device.

[0304] The upper layer of the first terminal device may include, alternatively be, or be understood as, the NAS layer of the first terminal device.

[0305] "The first terminal device may determine the RRC connection resumption cause based on the access identification" may include, or alternatively may be, or may be understood as follows: The first terminal device (e.g., the AS layer of the first terminal device) may determine the RRC connection resumption cause based on the access identification configured by a higher layer of the first terminal device.

[0306] The rule for determining or setting an RRC connection resumption cause corresponding to unicast and multicast may be understood as follows: The rule for determining or setting an RRC connection resumption cause corresponding to unicast and multicast is applicable when the first paging message includes a first identifier of the first terminal device and an identifier of the first multicast service. Specifically, when the first paging message includes a first identifier of the first terminal device and an identifier of the first multicast service, the first terminal device may alternatively determine the RRC connection resumption cause based on the rule for determining or setting an RRC connection resumption cause corresponding to unicast and multicast.

[0307] It should be noted that the rules for determining or setting the RRC connection resumption cause corresponding to unicast and multicast may be specified in a protocol, or may be pre-configured or configured for the first terminal device by the network device. The specific rules are not limited in this application.

[0308] In a possible implementation, the first terminal device determining the first RRC connection resumption cause according to the third policy includes: (1) when Access Identification 1 is configured by an upper layer of the first terminal device, setting a first RRC connection resumption cause to mps-PriorityAccess; (2) setting the first RRC connection resumption cause to mcs-PriorityAccess when access identification 1 is not configured by the upper layer of the first terminal device and access identification 2 is configured by the upper layer of the first terminal device; (3) setting the first RRC connection resumption cause to highPriorityAccess when Access Identification 1 and Access Identification 2 are not configured by the upper layer of the first terminal device and one or more of Access Identification 11 to Access Identification 15 are configured by the upper layer of the first terminal device; or (4) Setting the first RRC connection resumption cause to unicast and multicast access when access identification 1, access identification 2, and access identification 11 to access identification 15 are not configured by an upper layer of the first terminal device. may include any one or more of:

[0309] In yet another possible implementation, the third policy may include multiple RRC connection resumption causes, and the first terminal device may select the RRC connection resumption cause with the highest priority from the multiple RRC connection resumption causes as the RRC connection resumption cause. For example, the multiple RRC connection resumption causes included in the third policy include mps-PriorityAccess and mps-PriorityAccess, and mps-PriorityAccess has the highest priority. When the first paging message includes an identifier of the first multicast service and a first identifier of the first terminal device, the first terminal device sets the RRC connection resumption cause to mps-PriorityAccess.

[0310] In yet another possible implementation, when the first paging message includes an identifier of the first multicast service and a first identifier of the first terminal device, the first terminal device sets the RRC connection resumption cause to unicast and multicast, and unicast and multicast are the RRC connection resumption causes of the third policy.

[0311] In solution d4, an RRC connection resumption cause that is applicable when the first paging message includes an identifier of the first terminal device and an identifier of the first multicast service may be defined, added, or configured.

[0312] It should be noted that in a possible implementation, the third policy and the first policy may be different.

[0313] Note that in a possible implementation, the third policy and the second policy may be different.

[0314] It should be noted that the third configuration information may be different or the same as the first configuration information or the second configuration information. This is not limited in the present application. Whether it is different or the same is not limited in the present application.

[0315] It should be noted that the rules for determining or setting the RRC connection resumption cause corresponding to unicast and multicast may be different or the same as the rules for determining or setting the RRC connection resumption cause corresponding to unicast or the rules for determining or setting the RRC connection resumption cause corresponding to multicast. This is not limited in this application. Whether it is different or the same is not limited in this application.

[0316] It should be noted that the RRC connection resumption cause corresponding to unicast and multicast may be different or the same as the RRC connection resumption cause corresponding to unicast or the RRC connection resumption cause corresponding to multicast, which is not limited in this application.

[0317] It should be noted that the access identity of solution d4 may be different or the same as the access identity of solution d1 or the access identity corresponding to the multicast of solution d2, which is not limited in this application.

[0318] For one of the cases corresponding to condition 1, condition 2, and condition 3, the first terminal device may implement one of solution d1, solution d2, solution d3, or solution d4.

[0319] Optionally, if condition 1 is met, the first terminal device implements solution d2.

[0320] Optionally, if condition 2 is met, the first terminal device implements one of solution d1, solution d2, solution d3, or solution d4.

[0321] Optionally, if condition 3 is met, the first terminal device implements solution d1.

[0322] It should be noted that step S306 may alternatively be used as an independent embodiment and is not dependent on steps S302 to S305, for example, S301 and S306 may be used as separate embodiments.

[0323] It should be noted that in the embodiment of the present application, the above content is described using a first terminal device as an example. The first paging message may further include an identifier (first identifier or second identifier) ​​of another terminal device, or may not include an identifier (first identifier or second identifier) ​​of another terminal device. This is not limited in the embodiment of the present application. In the embodiment of the present application, the above content is described using a first multicast service as an example. The first paging message may further include identifiers of one or more other multicast services, or may not include an identifier of another multicast service. This is not limited in the embodiment of the present application.

[0324] Based on the foregoing, FIG. 3b is a schematic flowchart example of yet another possible communication method according to an embodiment of the present application, as shown in FIG. 3b.

[0325] As shown in FIG. 3b, the method includes the following steps:

[0326] S301A: A first terminal device receives a first paging message.

[0327] After step S301A, the first terminal device may perform the following step S302A or S303A.

[0328] For step S301A, please refer to S301 above, and the details will not be described again here.

[0329] S302A: The first terminal device initiates RRC connection resumption. For step S302A, please refer to S302 above. The details will not be described again here.

[0330] S303A: The first terminal device enters an RRC idle state. For step S303A, please refer to S303 above. The details will not be described again here.

[0331] When the fourth condition is met, the first terminal device may perform step S302A.

[0332] When the fifth condition is met, the first terminal device may perform step S303A.

[0333] The fourth condition includes any one of the first condition, the second condition, the third condition, and the fourth condition.

[0334] The fifth condition includes the fifth condition.

[0335] Optionally, after step S302A, the first terminal device may perform the following step S304A. Alternatively, optionally, "the first terminal device initiates an RRC connection resumption" may include: the first terminal device sends a first message. For the relevant content of the first message, please refer to the above description. The details will not be described again.

[0336] S304A: The first terminal device sends a first message.

[0337] For step S304A, please refer to S304 above, and the details will not be described again here.

[0338] Optionally, after step S303A, the first terminal device may perform the following step S305A. Alternatively, optionally, "the first terminal device enters an RRC idle state" may include: the first terminal device sends a second message. For the relevant content of the second message, please refer to the above description. The details will not be described again.

[0339] It should be noted that the order of step S302A and step S304A is not limited in the present application.

[0340] S305A: The first terminal device sends a second message.

[0341] For step S305A, please refer to S305 above, and the details will not be described again here.

[0342] It should be noted that the order of step S303A and step S305A is not limited in the present application.

[0343] Optionally, the application further includes: the first terminal device performing the following step S306A.

[0344] S306A: The first terminal device determines a first RRC connection resumption cause.

[0345] For step S306A, please refer to S306 above, and the details will not be described again here.

[0346] In a possible implementation, the first RRC connection resumption cause may be carried in the first message, in which case S306A may be performed before S304A (FIG. 3b is shown with this example).

[0347] Optionally, if condition 1 is met, the first terminal device implements solution d2.

[0348] Optionally, if condition 2 or condition 4 is met, the first terminal device implements one of solution d1, solution d2, solution d3, or solution d4.

[0349] Optionally, if condition 3 is met, the first terminal device implements solution d1.

[0350] It should be noted that step S306A may alternatively be used as an independent embodiment and is not dependent on steps S302A to S305A, for example, S301A and S306A may be used as separate embodiments.

[0351] It should be noted that the order of steps S302A to S304A may be consistent with or different from that shown in Figure 3b. For example, S306A may be performed before S302A and S304A. The order is not limited in this application.

[0352] For the content or description of the method of Fig. 3b, please refer to the description of the method of Fig. 3a, and the details will not be described again here.

[0353] Based on the solution shown in FIG. 3b, after receiving the first paging message, the first terminal device may attempt to enter the RRC connected state in different manners under different conditions, thereby reducing the delay in the first terminal device entering the RRC connected state. For example, when the first paging message includes an identifier of the first multicast service and a second identifier of the first terminal device (Condition 4), if the first terminal device initiates RRC connection resumption after receiving the first paging message, and if the network device can acquire, confirm, or verify the UE context of the first terminal device, the first terminal device may enter the RRC connected state. Compared with the first terminal device entering the RRC idle state after receiving the first paging message and attempting to enter the RRC connected state via RRC connection setup, the first terminal device can enter the connected state more quickly by initiating RRC connection resumption after receiving the first paging message.

[0354] To more specifically describe the embodiments of the present application, the following describes some specific examples based on FIG. 3a and the above-described solution for determining the first RRC connection resumption cause.

[0355] Example 1: A first terminal device receives a first paging message from a fourth network device, where the first paging message includes an identifier of a first multicast service and a complete I-RNTI of the first terminal device. The first terminal device initiates an RRC connection resumption and selects a first RRC connection resumption cause as multicast access (in an actual application, another connection resumption cause may be selected based on the above). The first terminal device sends an RRC connection resumption request and adds indication information to the RRC connection resumption request indicating that the first RRC connection resumption cause is multicast access.

[0356] Example 2: A first terminal device receives a first paging message from a fourth network device, the first paging message including an identifier of a first multicast service and a 5G-S-TMSI of the first terminal device. The first terminal device enters an RRC idle state and sends an RRC connection setup request to set up an RRC connection.

[0357] Based on the foregoing, Figure 4 is a schematic flowchart example of another communication method according to an embodiment of the present application. The communication method shown in Figure 4 may be applicable to the system architecture shown in Figure 1 and / or Figure 2. For example, the solution performed on the terminal device side (e.g., the second terminal device or the third terminal device) of Figure 4 may be performed by the terminal device 11 of Figure 1, alternatively, by a module or chip of the terminal device 11, alternatively, by the terminal device (e.g., the terminal device 111, the terminal device 112, or the terminal device 113) of Figure 2, or alternatively, by a module or chip of the terminal device (e.g., the terminal device 111, the terminal device 112, or the terminal device 113) of Figure 2.

[0358] In another example, the solution performed by the first network device or the second network device of FIG. 4 may be performed by the network device 12 of FIG. 1, or alternatively, may be performed by a module or chip of the network device 12, or alternatively, may be performed by an access network device (e.g., access network device 121 or access network device 122) of FIG. 2, or alternatively, may be performed by a module or chip of the access network device (e.g., access network device 121 or access network device 122) of FIG. 2.

[0359] In another example, the solution performed by the third network device of FIG. 4 may be performed by network device 12 of FIG. 1, or alternatively, may be performed by a module or chip of network device 12, or alternatively, may be performed by a core network device of FIG. 2 (e.g., core network device 123 or core network device 124), or alternatively, may be performed by a module or chip of a core network device of FIG. 2 (e.g., core network device 123 or core network device 124).

[0360] The solution provided in FIG. 4 can alternatively be implemented in combination with the solution of FIG. 3a or FIG. 3b.

[0361] For example, the first terminal device in Figure 3a or 3b may be the second terminal device in Figure 4. The fourth network device in Figure 3a or 3b may be the first network device in Figure 4. In the solutions shown in Figures 3a and 3b, the first paging message received by the terminal device of S301 may be the fourth paging message sent by the first network device in Figure 4. The identifier of the first multicast service carried in the first paging message may be the third identifier or the fourth identifier of the second multicast service carried in the fourth paging message.

[0362] In another example, the first terminal device in Figure 3a or 3b may be the second terminal device in Figure 4. The fourth network device in Figure 3a or 3b may be the second network device in Figure 4. In the solution shown in Figures 3a and 3b, the first paging message received by the terminal device of S301 may be a paging message sent by the second network device in Figure 4 and used to page the second terminal device. The identifier of the first multicast service carried in the first paging message may be an identifier of the second multicast service carried in a paging message sent by the second network device and used to page the second terminal device.

[0363] In another example, the first terminal device in Figure 3a or 3b may be the third terminal device in Figure 4. The fourth network device in Figure 3a or 3b may be the first network device in Figure 4. In the solution shown in Figures 3a and 3b, the first paging message received by the terminal device of S301 may be a paging message sent by the first network device in Figure 4 and used to page the third terminal device. The identifier of the first multicast service carried in the first paging message may be a third identifier of the second multicast service.

[0364] The solution provided in Figure 4 and the solution in Figure 3a may be implemented separately. The solution provided in Figure 4 and the solution in Figure 3b may be implemented separately. Specifically, the first paging message received by the terminal device at S301 in Figure 3a may alternatively be another paging message other than the fourth paging message. For example, at S301, the terminal device may receive a paging message sent by another network device (a network device other than the first network device and the second network device).

[0365] Before the solution of Figure 4 is described, paging by the access network device of the embodiment of the present application will be described first. For ease of understanding, in some parts of the embodiment of the present application, access network paging will be referred to as RAN paging.

[0366] Currently, events that trigger an access network device to initiate RAN paging for a terminal device in an RRC inactive state may include the following events e1, e2, and e3: In other words, when any one of the following events e1, e2, or e3 is met, the terminal device's last serving access network device (e.g., serving gNB) pages the terminal device in a cell corresponding to the RNA or sends a paging message (e.g., XnAP RAN paging) to a neighboring access network device (if the RNA includes a neighboring access network device).

[0367] Event e1: When the last serving access network device receives downlink data for the terminal device from a core network device (e.g., UPF) or receives downlink UE-related signaling (other than a UE Context Release Command message) from a core network device (e.g., AMF).

[0368] Event e2: The last serving access network device receives a UE Context Release Command message.

[0369] Event e3: The last serving access network device receives an NG RESET message.

[0370] Currently, multicast paging has the following problems:

[0371] After the first network device (access network device) receives a second paging message from a third network device (core network device), the second paging message includes a third identifier of the multicast service. According to the prior art, the first network device pages a terminal device that supports the multicast service and is in an RRC idle state. After the terminal device in the RRC idle state enters an RRC connected state, the core network device transmits data of the multicast service to the first network device. The first network device triggers RAN paging only after receiving the data of the multicast service, and the first network device pages the terminal device in an RRC inactive state, so that the terminal device in the RRC inactive state enters a connected state.

[0372] It can be understood from the aforementioned scenario of the present application that paging is initiated for a terminal device in an RRC inactive state after a terminal device in an RRC idle state enters an RRC connected state and the first network device receives data of a multicast service from a core network device. As a result, a terminal device in an RRC inactive state enters a connected state later (in other words, a terminal device in an RRC inactive state associated with a multicast service enters a connected state later than a terminal device in an RRC idle state). The cause of this problem is that the core network device does not detect the terminal device in an RRC inactive state. Therefore, the second paging message initiated by the core network is to page the terminal device in an RRC idle state. However, the first network device triggers the first network device to page the terminal device in an RRC inactive state only when the aforementioned scenario e1 (downlink data is received) is met. The solution provided in FIG. 4 of an embodiment of the present application can solve this problem so that a terminal device associated with a multicast service in an RRC inactive state enters an RRC connected state earlier. A detailed description is provided below with reference to the accompanying drawings.

[0373] As shown in FIG. 4, the method includes the following steps:

[0374] S401: A first network device receives a second paging message.

[0375] At S401, the first network device may receive a second paging message from a third network device.

[0376] For example, the third network device may be a core network device, for example, the third network device may be an AMF.

[0377] For example, the first network device may be an access network device.

[0378] For example, the first network device is a network device that supports MBS or multicast.

[0379] "Supporting MBS or multicast" may include, be understood as, or be replaced with having MBS or multicast functionality.

[0380] The second paging message is associated with the multicast.

[0381] In a possible implementation, the second paging message is used to notify that a second multicast service has been activated, is used to notify that a second multicast session has been activated, indicates to the first network device to page a terminal device associated with the second multicast service, or indicates to the first network device to page a third terminal device associated with the second multicast service.

[0382] In a possible implementation, after receiving the second paging information, the first network device pages a terminal device associated with the second multicast service, or the first network device pages a third terminal device.

[0383] For example, the second paging message includes a third identifier of the second multicast service.

[0384] A third identifier of the second multicast service is associated with the second multicast service.

[0385] For example, the identifier of the multicast service, or the third identifier of the second multicast service, may include any one or more of the following: a TMGI, an MBS service identifier, a multicast service identifier, an MBS session identifier, a PDU session ID used to transmit the multicast service, etc.

[0386] Please note that the third identifier of the second multicast service may include, or alternatively may be, or may be understood as, information about the second multicast service or third information of the second multicast service.

[0387] It should be noted that a multicast service may include, or alternatively may be, or may be understood as, a multicast session, an MBS session, or an MBS service.

[0388] It should be noted that multicast may include, or alternatively may be, or may be understood as, MBS, broadcast, or groupcast.

[0389] It should be noted that the second paging message may include information about one or more multicast services, which is not a limitation in this application, and the second multicast service is used as an example for explanation in this application.

[0390] Optionally, the second paging message may further include an identifier of the third terminal device, or an identifier of the third terminal device and a DRX configuration of the third terminal device.

[0391] A third terminal device is associated with the second multicast service.

[0392] The third terminal device is in an RRC idle state.

[0393] It should be noted that the identifier of the third terminal device may include, or alternatively may be, or may be understood as, information about the third terminal device.

[0394] It should be noted that the third terminal device may include one or more terminal devices, which is not limited in this application.

[0395] For example, the identifier of the third terminal device may be the second identifier of the third terminal device.

[0396] For example, the second identifier of the third terminal device is associated with the CN paging.

[0397] For example, the second identifier of the third terminal device may be provided or assigned by an upper layer of the third terminal device (e.g., a NAS layer of the third terminal device). Alternatively, the second identifier of the third terminal device may be provided or assigned to the third terminal device (e.g., an AS layer of the third terminal device) by an upper layer of the third terminal device (e.g., a NAS layer of the third terminal device).

[0398] For example, the second identifier of the third terminal device may be provided by a core network device (e.g., a third network device) of the third terminal device. Note that the second identifier of the third terminal device may be transmitted to the third terminal device by the core network device, or may be transmitted to the third terminal device by the core network device using an access network device. This is not limited in the present application.

[0399] For example, the second identifier of the third terminal device may be used to identify (eg, uniquely identify) the third terminal device in a tracking area.

[0400] For example, the second identifier of the third terminal device may include any one or more of the following: 5G-S-TMSI, S-TMSI, IMSI, and ng-5G-S-TMSI.

[0401] Please note that the second identifier of the third terminal device may include, or alternatively may be, or may be understood as, information about the third terminal device or second information of the third terminal device.

[0402] For example, the DRX configuration of the third terminal device may include a first DRX cycle of the third terminal device.

[0403] If possible, the first DRX cycle of the third terminal device is negotiated by the third terminal device and the core network (e.g., the third network device). Alternatively, the first DRX cycle of the third terminal device is configured or confirmed by the core network (e.g., the third network device) of the third terminal device.

[0404] For example, the first DRX cycle of the third terminal device is a DRX cycle specific to the third terminal device.

[0405] After step S401, the first network device may perform any one or more of steps S402, S403, S404, S404A, S405, and S406.

[0406] S402: The first network device determines a second terminal device.

[0407] The second terminal device is associated with the second multicast service, for example, the second terminal device includes a terminal device that participates in the second multicast service.

[0408] For example, the second terminal device is in an RRC inactive state.

[0409] It should be noted that the second terminal device being in an RRC inactive state includes the following: the first network device determines, recognizes, or considers the second terminal device to be in an RRC inactive state. It can be understood that a state deviation may occur between the terminal device and the network device. Therefore, the requirement that the second terminal device be in an RRC inactive state is not limited in this application.

[0410] For example, the second terminal device includes a terminal device that joins the second multicast service and is in an RRC inactive state.

[0411] It should be noted that the second terminal device may include one or more terminal devices.

[0412] Optionally, the first network device determining the second terminal device may include: the first network device determining whether the second terminal device exists.

[0413] At S402, the first network device may determine a second terminal device based on a third identifier of the second multicast service.

[0414] S402 may be an optional step and is not required.

[0415] The "first network device determining the second terminal device" may include any one or more of the following: (1) the first network device determines an identifier of the second terminal device; and (2) The first network device determines a first DRX period of the second terminal device and / or a second DRX period of the second terminal device.

[0416] For example, the identifier of the second terminal device may include a first identifier of the second terminal device and / or a second identifier of the second terminal device.

[0417] For example, the first identifier of the second terminal device is associated with RAN paging.

[0418] For example, the seventh message sent by the network device (e.g., the first network device) to the second terminal device may include information (some or all of the information) about the first identifier of the second terminal device.

[0419] The seventh message indicates or commands the release of the RRC connection or the suspension (eg, suspension) of the RRC connection.

[0420] For example, the seventh message may be an RRCRelease message.

[0421] For example, the eighth message sent by the second terminal device to a network device (e.g., the first network device or another network device) may include information (some or all of the information) about the first identifier of the second terminal device.

[0422] The eighth message requests that an interrupted (eg, suspended) RRC connection be resumed or that an RNA update be performed.

[0423] For example, the eighth message may be a RRCResumeRequest1 message.

[0424] For example, the size of the first identifier of the second terminal device may be 40 bits.

[0425] For example, the first identifier of the second terminal device is used to identify a suspended (e.g., suspended) UE context of the second terminal device, or is used to identify a UE context of the second terminal device.

[0426] For example, the first identifier of the second terminal device may include any one or more of the following: a complete I-RNTI, a complete I-RNTI of the second terminal device, a complete I-RNTI stored in the second terminal device, an I-RNTI (inactive RNTI), an I-RNTI of the second terminal device, and an I-RNTI stored in the second terminal device.

[0427] For example, a second identifier of a second terminal device is associated with the CN paging.

[0428] For example, the second identifier of the second terminal device may be provided or assigned by an upper layer of the second terminal device (e.g., a NAS layer of the second terminal device). Alternatively, the second identifier of the second terminal device may be provided or assigned to the second terminal device (e.g., an AS layer of the second terminal device) by an upper layer of the second terminal device (e.g., a NAS layer of the second terminal device).

[0429] For example, the second identifier of the second terminal device may be provided by a core network device (e.g., a third network device) of the second terminal device. Note that the second identifier of the second terminal device may be transmitted to the second terminal device by the core network device, or may be transmitted to the second terminal device by the core network device using an access network device. This is not limited in the present application.

[0430] For example, the second identifier of the second terminal device may be used to identify (eg, uniquely identify) the second terminal device in a tracking area.

[0431] For example, the second identifier of the terminal device or the second identifier of the second terminal device may include any one or more of the following: 5G-S-TMSI, S-TMSI, IMSI, and ng-5G-S-TMSI.

[0432] When possible, the first DRX cycle of the second terminal device is negotiated by the second terminal device and the core network (e.g., the third network device). Alternatively, the first DRX cycle of the second terminal device is configured or confirmed by the core network (e.g., the third network device) of the second terminal device.

[0433] For example, the first DRX cycle of the second terminal device is a DRX cycle specific to the second terminal device.

[0434] When possible, the second DRX cycle of the second terminal device is transmitted by the network device (e.g., the first network device) to the second terminal device. For example, the ninth message transmitted by the network device (e.g., the first network device) to the second terminal device includes the second DRX cycle of the second terminal device.

[0435] The ninth message indicates or commands the release of the RRC connection or the suspension (eg, suspension) of the RRC connection.

[0436] For example, the ninth message may be an RRCRelease message.

[0437] It should be noted that the seventh message and the ninth message may be the same message or different messages, which is not a limitation in this application.

[0438] Optionally, the first network device may be a last serving network device of the second terminal device. For example, the last serving network device may include a last serving gNB.

[0439] S403: The first network device calculates or determines a first paging occasion (PO).

[0440] The first PO is associated with a second terminal device.

[0441] The first network device calculating or determining a first paging occasion (PO) includes the first network device calculating or determining an index of the first paging occasion.

[0442] In a possible implementation, the first PO may be calculated or determined based on any one or more of the following: (1) a second identifier of the second terminal device; (2) the DRX period of the second terminal device; (3) the number of PFs in the DRX period of the second terminal device; and (4) The quantity of POs in the PF.

[0443] The DRX period of the second terminal device may be the smallest value in the first DRX period set.

[0444] The first DRX cycle set includes any one or more of the first DRX cycle of the second terminal device, the second DRX cycle of the second terminal device, and the default DRX cycle.

[0445] The default DRX period may be broadcast by the first network device, for example, the default DRX period may be included in system information (e.g., SIB 1) transmitted by the first network device.

[0446] It should be noted that the DRX period of the second terminal device determined by the first network device may be different from the DRX period of the second terminal device determined by the second terminal device, which is not limited in this application.

[0447] Note that the first PO may include multiple POs.

[0448] Optionally, step 403 further includes the first network device calculating or determining a first PF.

[0449] The first PF is associated with the second terminal device. In a possible implementation, the first PF may be calculated or determined based on any one or more of the following: (1) a second identifier of the second terminal device; (2) the DRX period of the second terminal device; (3) the number of PFs during the DRX period of the second terminal device; and (4) The offset value used to determine the PF.

[0450] Note that the first PF may include multiple PFs.

[0451] It should be noted that the method of "calculating or determining the first PO" in the present application may be the same as or different from that in the prior art (see the description of the prior art for details), which is not limited in the present application.

[0452] It should be noted that the method of "calculating or determining the first PF" in the present application may be the same as or different from that in the prior art (see the description of the prior art for details), which is not limited in the present application.

[0453] It should be noted that in a possible implementation, when the PO of a third terminal device includes the PO of a second terminal device (e.g., there is an overlap), paging (e.g., the DCI of the paging message) may be transmitted in the PO of the third terminal device (e.g., the overlapping PO).

[0454] It should be noted that in a possible implementation, when the PO of the second terminal device and the PO of the third terminal device do not overlap, the paging (e.g., the DCI of the paging message) needs to be sent separately in the PO of the second terminal device and the PO of the third terminal device.

[0455] S403 may be an optional step and is not required.

[0456] S404: The first network device triggers RAN paging.

[0457] For example, the first network device triggering RAN paging includes the first network device triggering RAN paging to the second terminal device and / or to the second multicast service.

[0458] Optionally, the application further includes the first network device triggering RAN paging when a sixth condition is met.

[0459] The sixth condition includes the first network device determining that a second terminal device is present.

[0460] Optionally, the first network device triggering RAN paging may include, or may be, or may be understood as, the first network device deciding to initiate RAN paging. In Figure 4, S404A is shown with a dashed line and is explicitly set forth within the step block of S404 to indicate that S404 may include, or alternatively may be, or may be understood as S404A.

[0461] S404A: The first network device determines to trigger RAN paging.

[0462] RAN paging may be understood to be triggered when a first event is met.

[0463] The first event includes the first network device receiving a second paging message.

[0464] In this application, an event may include, or alternatively may be, or may be understood as, a cause or a condition.

[0465] Optionally, RAN paging is triggered when the first event is met and a sixth condition is met.

[0466] The first event includes the first network device receiving a second paging message, the second paging message including a third identifier of the second multicast service.

[0467] In this application, an event may include, or alternatively may be, or may be understood as, a cause or a condition.

[0468] Optionally, the application further includes triggering RAN paging when the first event is met and a sixth condition is met.

[0469] For example, the solution provided in S402A of this embodiment of the present application can be understood as adding event e4, where event e4 includes the first network device receiving a second paging message from a third network device, where the second paging message includes a third identifier of the second multicast service.

[0470] For example, the solution provided in S402A of this embodiment of the present application can be understood as adding event e5. Event e5 includes the first network device receiving a second paging message from a third network device, the second paging message including a third identifier of the second multicast service, and a second terminal device being present. Alternatively, the solution provided in S402A of this embodiment of the present application can be understood as adding event e5. Event e5 includes the first network device receiving a second paging message from a third network device, the second paging message including a third identifier of the second multicast service, and the first network device determining that a second terminal device being present.

[0471] In a possible implementation, when scenario e4 is met, the first network device is triggered to initiate RAN paging to the second terminal device in an RRC inactive state.

[0472] In yet another possible implementation, at S402, when scenario e4 is met, the last serving access network device (e.g., serving gNB) of the second terminal device pages the second terminal device in the cell corresponding to the RNA configured for the second terminal device, or sends a paging message (e.g., XnAP RAN paging) to a neighboring access network device (if the RNA includes a neighboring access network device).

[0473] S405: The first network device pages the second terminal device.

[0474] In a possible implementation, the first network device may page the second terminal device in the cell corresponding to the RNA.

[0475] In a possible implementation, the first network device paging the second terminal device may include: the first network device sending first control information and a fourth paging message, where the first control information is used to schedule the fourth paging message, or the first control information includes scheduling information for the fourth paging message.

[0476] For example, a first network device transmits first control information regarding a first paging occasion and transmits a fourth paging message on a resource indicated by the first control information.

[0477] In another example, a first network device transmits first control information regarding a first paging occasion in a cell corresponding to an RNA corresponding to a second terminal device.

[0478] The fourth paging message includes a third identifier of the second multicast service and / or an identifier of the second terminal device (e.g., a first identifier of the second terminal device or a second identifier of the second terminal device). Alternatively, the fourth paging message includes a fourth identifier of the second multicast service and / or an identifier of the second terminal device (e.g., a first identifier of the second terminal device or a second identifier of the second terminal device).

[0479] For example, the fourth paging message may be used to notify that a second multicast service has been activated, to notify that a second multicast session has been activated, or to page a second terminal device.

[0480] A fourth identifier of the second multicast service is associated with the second multicast service.

[0481] For example, the identifier of the multicast service or the fourth identifier of the second multicast service may include any one or more of the following: a TMGI, an MBS service identifier, and a wireless network temporary identifier (e.g., a G-RNTI and a G-CS-RNTI) used to schedule the MBS service or the multicast service, a multicast service identifier, an MBS session identifier, a PDU session ID used to transmit the multicast service, etc.

[0482] Please note that the fourth identifier of the second multicast service may include, or alternatively may be, or may be understood as, information about the second multicast service or fourth information of the second multicast service.

[0483] It should be noted that the third identifier of the second multicast service may be the same as or different from the fourth identifier of the second multicast service, which is not limited in this application.

[0484] For example, the first control information may be transmitted on a physical downlink control channel (PDCCH), e.g., the first control information is a first DCI.

[0485] For example, the fourth paging message may be transmitted on a physical downlink shared channel (PDSCH).

[0486] In a possible implementation, the first DCI may include a short message service indication field (short message service indicator). The short message service indication field indicates whether the first DCI includes scheduling information for a fourth paging message, indicates whether a PDSCH (e.g., the fourth paging message) is scheduled by the first DCI, or indicates whether a short message service is included. When the short message service indication field indicates that the first DCI schedules the fourth paging message, the second terminal device receives the fourth paging message based on the first control information.

[0487] S406: The first network device sends a third paging message to the second network device, where the third paging message indicates to the second network device to page the second terminal device.

[0488] The RNA corresponding to the second terminal device includes the second network device, or the RNA includes the second network device.

[0489] The second network device may be a network device that supports MBS or multicast or does not support MBS or multicast, which is not limited in this application.

[0490] The third paging message includes one of the following: (a) an identifier of the second terminal device; (b) an identifier of the second terminal device and a DRX period of the second terminal device; (c) an identifier of a second terminal device, a DRX period of the second terminal device, and an identifier of a second multicast service; or (d) an identifier of a second multicast service;

[0491] The identifier of the second multicast service may include a third identifier of the second multicast service, a fourth identifier of the second multicast service, or a fifth identifier of the second multicast service.

[0492] For example, the identifier of the second terminal device may include a first identifier of the second terminal device and / or a second identifier of the second terminal device.

[0493] A fifth identifier of the second multicast service is associated with the second multicast service.

[0494] For example, the identifier of the multicast service, or the fifth identifier of the second multicast service, may include any one or more of the following: a temporary mobile group identity (TMGI), an MBS service ID, a multicast service identifier, an MBS session ID, a protocol data unit (PDU) session ID used to transmit the multicast service, etc.

[0495] Please note that the fifth identifier of the second multicast service may include, or alternatively may be, or may be understood as, information about the second multicast service or fifth information of the second multicast service.

[0496] It should be noted that the fifth identifier of the second multicast service may be the same as or different from the third identifier of the second multicast service or the fourth identifier of the second multicast service, which is not limited in this application.

[0497] In possible implementations, the second paging message is used to notify that a second multicast service has been activated, is used to notify that a second multicast session has been activated, indicates to the first network device to page a terminal device associated with the second multicast service, indicates to the second network device to page a second terminal device associated with the second multicast service, or indicates to the second network device to page the second terminal device.

[0498] In a possible implementation, after receiving the third paging information, the second network device pages the terminal device associated with the second multicast service, or the second network device pages the second terminal device.

[0499] In an optional implementation, the second network device is a network device that supports MBS or multicast, and the third paging message includes any one of (a), (b), (c), and (d).

[0500] In another optional implementation, the second network device is a network device that does not support MBS or multicast, and the third paging message includes any one of (a) and (b).

[0501] It may be understood that the second network device may initiate paging to the second terminal device based on the third paging message and by using the content carried in the third paging message.

[0502] Optionally, the third paging message may further include one or more of the following contents: paging priority, auxiliary information, radio capabilities of the second terminal device, etc.

[0503] S402, S403, S404A, S404, S405, and S406 may be performed separately or together, which is not a limitation in this application.

[0504] For example, the first network device may perform S405 and S406. In this case, the first network device may page the first terminal device or may indicate to the second network device to page the first terminal device.

[0505] In another example, the first network device may perform S404 and S405. In this case, the first network device may trigger RAN paging and page the first terminal device.

[0506] In another example, the first network device may perform S404 and S406. In this case, the first network device may trigger RAN paging and indicate to the second network device to page the first terminal device.

[0507] In another example, the first network device may perform S404, S405, and S406. In this case, the first network device may trigger RAN paging, page the first terminal device, and indicate to the second network device to page the first terminal device.

[0508] It should be noted that Figure 4 only shows a possible execution order of the method steps, and other orders are possible between the steps of Figure 4. This is not limited in the present application. For example, S402 and S403 may be performed after S404. In another example, S406 may be performed before S405.

[0509] In a possible implementation, in an embodiment of the present application, the second paging message may include a third identifier of the second multicast service, but not an identifier of the second terminal device (e.g., not including the second identifier and the first identifier of the second terminal device).

[0510] In yet another possible implementation, the second paging message includes a third identifier of the second multicast service and an identifier of another terminal device associated with the second multicast service (e.g., includes a second identifier of the third terminal device). Note, however, that the identifier of the other terminal device associated with the second multicast service included in the second paging message is an identifier of a terminal device associated with the second multicast service and in an RRC idle state, and an identifier of a terminal device associated with the second multicast service and in an RRC inactive state is not included in the second paging message. Because the RRC inactive state is not sensed by the core network device, the core network device cannot distinguish a terminal device in an RRC inactive state from a terminal device in an RRC connected state.

[0511] However, in an embodiment of the present application, after receiving the second paging message, the first network device may calculate a paging occasion for the third terminal device in the RRC idle state or may calculate a paging occasion for the second terminal device in the RRC inactive state, and initiate paging for the third terminal device in the RRC idle state and the second terminal device in the RRC inactive state before receiving data of the second multicast service. Compared with a solution in which paging is initiated for the second terminal device in the RRC inactive state after data of the second multicast service is received, this implementation can reduce the delay in entering the RRC connected state by the second terminal device in the RRC inactive state after the multicast session is activated.

[0512] In a possible implementation, in response to the identifier of the third terminal device carried in the second paging message, the first paging message may further carry identifiers of one or more tracking areas (TAs) corresponding to the third terminal device and / or a DRX period. After receiving the first paging message, the first network device may page the third terminal device in the one or more tracking areas indicated in the first paging message. For each cell in the tracking area, the access network node may generate one page over the wireless air interface. The first paging message may further include a DRX period for use in the NG-RAN. The DRX configuration may be negotiated by the third terminal device with the core network device using a NAS message before the core network device sends the DRX configuration to the access network device.

[0513] It should be noted that in an embodiment of the present application, after receiving a paging message, the second terminal device in the RRC inactive state may initiate an RRC connection resumption in the RRC inactive state or enter the RRC idle state. The solution shown in FIG. 4 does not impose any restrictions on the solution of the second terminal device. In other words, in the solution shown in FIG. 4, the second terminal device side may implement the solution related to the terminal device side shown in FIG. 3a or 3b. Alternatively, the solution related to the terminal device side shown in FIG. 3a or 3b may not be referenced. Similarly, the solution shown in FIG. 3a or 3b does not impose any restrictions on the solution of the network device. In other words, in the solution shown in FIG. 3a or 3b, the network device may implement the solution related to the first network device shown in FIG. 4, or may not implement the solution related to the first network device shown in FIG. 3a or 3b. For example, the network device of FIG. 3a or 3b may implement the solution of the second network device. It should be noted that in paging initiated by a core network device (CN paging), the paging message may be sent to the terminal device via one or more other network elements, for example, via an access network device.

[0514] It should be understood that the prior art may change as technical solutions evolve, and the technical solutions provided in this application are not limited to the prior art provided.

[0515] It should be noted that different embodiments of the present application, or some steps of different embodiments, may be combined with each other.

[0516] To implement the functions in the above-described embodiments, the communication device can be understood to include corresponding hardware structures and / or software modules for implementing each function. Those skilled in the art can easily recognize that the present application can be implemented using hardware or a combination of hardware and computer software with respect to the combination of units and method steps in the examples described in the embodiments disclosed in the present application. Whether the functions are implemented using hardware or by hardware driven by computer software depends on the specific application scenario and the design constraints of the technical solution.

[0517] 5, 6, and 7 are schematic diagrams of possible communication device structures according to embodiments of the present application. The communication device may be configured to implement the functions of the terminal device in the aforementioned method embodiments, and thus may also implement the beneficial effects of the aforementioned method embodiments. Alternatively, the communication device may be configured to implement the functions of the first network device in the aforementioned method embodiments, and thus may also implement the beneficial effects of the aforementioned method embodiments. In embodiments of the present application, the communication device may be a terminal device, for example, the terminal device of FIG. 1 or 2, the first terminal device of FIG. 3A or 3B, or the second or third terminal device of FIG. 4, or alternatively, a module (e.g., a chip) used in the terminal device. In embodiments of the present application, the communication device may alternatively be a network device, for example, the network device of FIG. 1 or 2, the fourth network device of FIG. 3A or 3B, or the first network device of FIG. 4, or alternatively, a module (e.g., a chip) used in the network device.

[0518] 5, the communication apparatus 1300 includes a processing unit 1310 and a transceiver unit 1320. The communication apparatus 1300 is configured to implement the functions of the terminal device in the method embodiments shown in FIGS. 3a and 3b, for example, may implement the functions of the first terminal device in FIG. 3a or 3b.

[0519] The processing unit 1310 is configured to receive a first paging message using the transceiver unit 1320. The terminal device initiates radio resource control (RRC) connection resumption when a first condition is met. For related content of the first condition, please refer to the description in the preceding method embodiment. The details will not be described again here.

[0520] The processing unit 1310 is further configured to transmit a first message using the transceiver unit 1320. The first message is used to request to resume the RRC connection.

[0521] When the communication apparatus 1300 is configured to implement the functionality of a first terminal device in the method embodiment shown in FIGS. 3a and 3b, the processing unit 1310 is further configured to perform, using the transceiver unit 1320, one of the following: determining, by the terminal device, a first RRC connection resumption cause according to a first policy, the first policy including at least one of an access identification, an RRC connection resumption cause corresponding to unicast, and a rule for determining the RRC connection resumption cause corresponding to unicast; determining, by the terminal device, a first RRC connection resumption cause according to a second policy, the second policy including at least one of an access identification corresponding to multicast, an RRC connection resumption cause corresponding to multicast, and a rule for determining an RRC connection resumption cause corresponding to multicast; determining, by the terminal device, the first RRC connection resumption cause according to the first policy and the second policy; or determining, by the terminal device, the first RRC connection resumption cause according to a third policy, the third policy including at least one of an access identification, an RRC connection resumption cause corresponding to unicast and multicast, or a rule for determining an RRC connection resumption cause corresponding to unicast and multicast.

[0522] The processing unit 1310 is further configured to use the transceiver unit 1320 to implement: the terminal device determining a second RRC connection resumption cause according to the first policy; the terminal device determining a third RRC connection resumption cause according to the second policy; and the terminal device determining one of the second RRC connection resumption cause and the third RRC connection resumption cause as the first RRC connection resumption cause.

[0523] The processing unit 1310 is further configured to determine, using the transceiver unit 1320, that the terminal device determines the first RRC connection resumption cause according to a second policy, where the second policy includes at least one of an access identification corresponding to multicast, an RRC connection resumption cause corresponding to multicast, or a rule for determining an RRC connection resumption cause corresponding to multicast.

[0524] The processing unit 1310 is further configured to, using the transceiver unit 1320, enforce that the terminal device enters an RRC idle state when a second condition is met. The second condition includes: the first paging message includes an identifier of the first multicast service and a second identifier of the terminal device, and the second identifier of the terminal device is associated with core network CN paging; or the first paging message includes the second identifier of the terminal device.

[0525] The processing unit 1310 is further configured to transmit a second message using the transceiver unit 1320. The second message is used to request to set up an RRC connection.

[0526] 5, the communication apparatus 1300 includes a processing unit 1310 and a transceiver unit 1320. The communication apparatus 1300 is configured to implement the functionality of the network device in the method embodiment shown in FIG. 4, e.g., to implement the functionality of a first network device.

[0527] The processing unit 1310 is configured to implement, by using the transceiver unit 1320, that the first network device receives a second paging message, where the second paging message includes a third identifier of the second multicast service. The first network device implements one or more of the following: the first network device triggers RAN paging; the first network device pages the terminal device, where the terminal device is in an RRC inactive state and the terminal device is associated with the second multicast service; or the first network device sends a third paging message to the second network device, where the third paging message indicates to the second network device to page the terminal device.

[0528] The processing unit 1310 is further configured to perform, using the transceiver unit 1320, the first network device transmitting first control information and a fourth paging message. The first control information is used to schedule the fourth paging message, and the fourth paging message includes a third identifier of the second multicast service and / or an identifier of the terminal device, or the fourth paging message includes a fourth identifier of the second multicast service and / or an identifier of the terminal device.

[0529] The processing unit 1310 is specifically configured to use the transceiver unit 1320 to implement, by the first network device, transmitting first control information at the first paging occasion.

[0530] The processing unit 1310 is specifically configured to use the transceiver unit 1320 to perform the first network device paging a terminal device in a cell corresponding to a radio access network notification area.

[0531] For a more detailed description of the processing unit 1310 and the transceiver unit 1320, please directly refer to Figures 3a and 3b or the relevant description of the method embodiment shown in Figure 4. Details will not be described here.

[0532] 6, the communication device 1400 includes a processing circuit 1410 and an interface circuit 1420. The processing circuit 1410 and the interface circuit 1420 are coupled to each other. The interface circuit 1420 may be understood to be a transceiver or an input / output interface. Optionally, the communication device 1400 may further include a memory configured to store instructions to be executed by the processing circuit, to store input data required for the processing circuit 1410 to execute the instructions, or to store data generated after the processing circuit 1410 executes the instructions.

[0533] When the communication device 1400 is configured to implement the method shown in Figures 3a and 3b or 4, the processing circuit 1410 is configured to perform the functions of the processing unit 1310, and the interface circuit 1420 is configured to perform the functions of the transceiver unit 1320.

[0534] 7, the communication device 1500 includes a processor 1510 and a communication interface 1520. The processor 1510 and the communication interface 1520 are coupled to each other. The communication interface 1520 may be understood to be a transceiver or an input / output interface. Optionally, the communication device 1500 may further include a memory 1530 configured to store instructions to be executed by the processor 1510, to store input data required for the processor 1510 to execute the instructions, or to store data generated after the processor 1510 executes the instructions.

[0535] When the communication device 1500 is configured to implement the method shown in Figures 3a and 3b or 4, the processor 1510 is configured to perform the functions of the processing unit 1310, and the communication interface 1520 is configured to perform the functions of the transceiver unit 1320.

[0536] 3a and 3b, the processor 1510 is configured to receive a first paging message via the communication interface 1520. The terminal device initiates radio resource control (RRC) connection resumption when a first condition is met. For details regarding the first condition, please refer to the description in the preceding method embodiment. The details will not be described again here.

[0537] 4, the processor 1510 is configured to perform the following: the first network device receives, via the communication interface 1520, a second paging message, the second paging message including a third identifier of the second multicast service. The first network device performs one or more of the following: the first network device triggers RAN paging; the first network device pages the terminal device, the terminal device is in an RRC inactive state, and the terminal device is associated with the second multicast service; or the first network device sends a third paging message to the second network device, the third paging message indicating that the second network device pages the terminal device.

[0538] When the communication device is a chip used in the communication device, the chip in the communication device implements the functions of the communication device in the above-mentioned method embodiments. The chip in the communication device receives information from another module (e.g., a radio frequency module or an antenna) in the communication device, and this information is transmitted to the communication device by the network device. Alternatively, the chip in the communication device transmits information to another module (e.g., a radio frequency module or an antenna) in the communication device, and this information is transmitted to the network device by the communication device.

[0539] It should be understood that the processor referred to in the embodiments of this application may be a central processing unit (CPU), or may be another 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 transistor logic device, a hardware component, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0540] According to the method provided in the embodiments of the present application, the present application further provides a computer program product, which includes a computer program or instructions, which, when executed by a computer, enables the computer to perform any one of the methods of the embodiments shown in Figure 3a, Figure 3b, or Figure 4.

[0541] According to the method provided in the embodiment of the present application, the present application further provides a computer-readable storage medium, which stores a program or instruction, and when the program or instruction is executed by a computer, the computer is enabled to perform any one of the methods of the embodiments shown in Figure 3a, Figure 3b, or Figure 4.

[0542] According to the method provided in the embodiments of the present application, the present application further provides a chip system. The chip system may include a processor. The processor may be coupled to a memory and configured to perform the method of any one of the embodiments shown in FIG. 3A, FIG. 3B, or FIG. 4. Optionally, the chip system further includes a memory. The memory is configured to store a computer program (also referred to as code or instructions). The processor is configured to call the computer program from the memory and execute the computer program so that a device in which the chip system is installed performs the method of any one of the embodiments shown in FIG. 3A, FIG. 3B, or FIG. 4.

[0543] Based on the method provided in the embodiment of the present application, the present application further provides a system including the aforementioned terminal device and a first network device.

[0544] The method steps in the embodiments of the present application may be implemented by hardware or by a processor executing software instructions. The software instructions may include corresponding software modules. The software modules may be stored in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory (EPROM), registers, a hard disk, a solid-state drive (SSD), a removable hard disk, a compact disc read-only memory (CD-ROM), or any other form of storage medium well known in the art. For example, a storage medium may be coupled to the processor, thereby enabling the processor to read information from or write information to the storage medium. Indeed, the storage medium may be a component of the processor. The processor and the storage medium may be located in an ASIC. In addition, the ASIC may be located in a communication device. Of course, the processor and the storage medium may reside as discrete components in a communications device.

[0545] All or part of the above-described embodiments may be implemented using software, hardware, firmware, or any combination thereof. When software is used to implement an embodiment, all or part of the embodiment may be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, all or part of the procedures or functions of the embodiments of the present application are performed. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or another programmable apparatus. The computer program or 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 program or instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center via a wired or wireless method. 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, that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital video disks), or semiconductor media (e.g., solid-state disks). The computer-readable storage media may be volatile or nonvolatile storage media, or may include both types of storage media: volatile and nonvolatile storage media.

[0546] In the embodiments of the present application, unless otherwise specified or there is no logical contradiction, the terms and / or descriptions are consistent among different embodiments and may be cross-referenced, and the technical features in different embodiments may be combined based on their internal logical relationships to form new embodiments.

[0547] In the embodiments of the present application, "comprises" may be alternatively replaced with "exists," "holds," "matches in protocol," etc. In the embodiments of the present application, "does not include" may be alternatively replaced with "does not exist," "does not hold," "does not match in protocol," etc.

[0548] In this application, "plurality" refers to two or more. "And / or" describes an association relationship between related objects and indicates that three relationships may exist. For example, A and / or B indicates the following: only A is present, both A and B are present, and only B is present, where A and B may be singular or plural. In textual descriptions in this application, the character " / " indicates an "or" relationship between related objects. In mathematical formulas in this application, the character " / " indicates a "divide by" relationship between related objects. "Comprising at least one of A, B, or C" may indicate including A, including B, including C, including A and B, including A and C, including B and C, or including A, B, and C.

[0549] It can be understood that various numbers in the embodiments of the present application are used merely for distinction to facilitate description, and are not used to limit the scope of the embodiments of the present application. The order numbers of the above processes do not mean the order of execution, and the order of execution of the processes is determined based on the functions and internal logic of the processes.

Claims

1. A communication method for a terminal device, comprising: receiving a first paging message; initiating a radio resource control (RRC) connection resumption if the first paging message includes an identifier of a first multicast service and does not include a second identifier of the terminal device; Including, 1. The method of claim 1, wherein the second identifier of the terminal device is provided by a Non-Access Stratum (NAS) layer of the terminal device, and the second identifier of the terminal device includes any one or more of a 5G S-Temporary Mobile Subscription Identifier (5G-S-TMSI), a System Architecture Evolution Temporary Mobile Station Identifier (S-TMSI), an International Mobile Subscriber Identity (IMSI), or an ng-5G-S-TMSI.

2. The method of claim 1 , further comprising: determining a first RRC connection resumption cause according to an Access Identification (AI).

3. The step of determining a first RRC connection resumption cause according to access identification includes: if Access Identification 1 is configured by an upper layer of the terminal device, setting the first RRC connection resumption cause to Multimedia Priority Service-Priority Access mps-PriorityAccess; if the access identification 1 is not configured by the upper layer of the terminal device and the access identification 2 is configured by the upper layer of the terminal device, setting the first RRC connection resumption cause to mission critical services-priority access mcs-PriorityAccess; if Access Identification 1 and Access Identification 2 are not configured by the higher layer of the terminal device and one or more of Access Identification 11 to Access Identification 15 are configured by the higher layer of the terminal device, setting the first RRC connection resumption cause to highPriorityAccess; or setting the first RRC connection resumption cause to mobile terminated access mt-Access if the access identification 1, the access identification 2, and the access identification 11 to the access identification 15 are not configured by the higher layer of the terminal device; The method of claim 2 , comprising:

4. After the step of receiving a first paging message, the method further comprises: The method of claim 1 , further comprising: determining that the terminal device enters an RRC idle state when the first paging message includes the second identifier of the terminal device.

5. The method of claim 4 further comprising the step of determining that the release cause is "other."

6. The method of claim 1 , wherein the multicast service includes a multicast service in which the terminal device participates.

7. The method of claim 1 , wherein the terminal device is in an RRC inactive state.

8. The method of claim 1 , wherein the identifier of the first multicast service is a Temporary Mobile Group Identity (TMGI).

9. 2. The method of claim 1, further comprising: if the first paging message includes the identifier of the first multicast service, transmitting the identifier of the first multicast service to the NAS layer of the terminal device.

10. The step of initiating an RRC connection resumption comprises:

2. The method of claim 1, comprising: transmitting a first message, the first message being used to request a resumption of an RRC connection.

11. The method of claim 10 , wherein the first message is an RRCResumeRequest message or an RRCResumeRequest1 message.

12. 11. The method of claim 10, wherein the first message includes information of a first identifier of a first terminal device, and the first identifier of the first terminal device is used to identify a suspended UE context of the first terminal device or is used to identify the UE context of the first terminal device.

13. 13. The method of claim 12, wherein the first identifier of the first terminal device comprises one or more of a complete I-RNTI, a complete I-RNTI of the first terminal device, a complete I-RNTI stored on the first terminal device, an I-RNTI, an I-RNTI of the first terminal device, or an I-RNTI stored on the first terminal device.

14. A communication apparatus for a terminal device comprising a processing unit and a transceiver unit, The transceiver unit is configured to receive a first paging message, The processing unit is configured to start radio resource control (RRC) connection re-establishment when the first paging message includes an identifier of a first multicast service and does not include a second identifier of the terminal device, The second identifier of the terminal device is provided by a non-access stratum (NAS) layer of the terminal device, and the second identifier of the terminal device includes any one or more of a 5G S-temporary mobile subscription identifier (5G-S-TMSI), a system architecture evolution temporary mobile station identifier (S-TMSI), an international mobile subscriber identifier (IMSI), or an ng-5G-S-TMSI, a communication device.

15. The communication device according to claim 14, wherein the processing unit is further configured to determine a first RRC connection re-establishment cause according to an access identifier (AI).

16. The processing unit, when access identifier 1 is configured by an upper layer of the terminal device, set the first RRC connection re-establishment cause to multimedia priority service - priority access mps-PriorityAccess, when access identifier 1 is not configured by the upper layer of the terminal device and access identifier 2 is configured by the upper layer of the terminal device, set the first RRC connection re-establishment cause to mission critical service - priority access mcs-PriorityAccess, when neither access identifier 1 nor access identifier 2 is configured by the upper layer of the terminal device and one or more of access identifiers 11 to 15 are configured by the upper layer of the terminal device, set the first RRC connection re-establishment cause to high priority access highPriorityAccess, or when access identifier 1, access identifier 2, and access identifiers 11 to 15 are not configured by the upper layer of the terminal device, set the first RRC connection re-establishment cause to mobile terminal access mt-Access The communication device according to claim 14, which is further configured as follows.

17. The communications apparatus of claim 14 , wherein the processing unit is further configured to determine that the terminal device enters an RRC idle state when the first paging message includes the second identifier of the terminal device.

18. The communication device of claim 14 , wherein the processing unit is further configured to determine that the release cause is “other.”

19. The communication apparatus of claim 14 , wherein the multicast service includes a multicast service in which the terminal device participates.

20. The communications apparatus of claim 14 , wherein the terminal device is in an RRC inactive state.

21. The communications device of claim 14 , wherein the identifier of the first multicast service is a Temporary Mobile Group Identity (TMGI).

22. 15. The communications apparatus of claim 14, wherein the transceiver unit is further configured to, when the first paging message includes the identifier of the first multicast service, transmit the identifier of the first multicast service to the NAS layer of the terminal device.

23. The communications device of claim 14 , wherein the transceiver unit is further configured to transmit a first message, the first message being used to request a resumption of an RRC connection.

24. The communications device of claim 23 , wherein the first message is an RRCResumeRequest message or an RRCResumeRequest1 message.

25. 24. The communication apparatus according to claim 23, wherein the first message includes information of a first identifier of a first terminal device, and the first identifier of the first terminal device is used to identify a suspended UE context of the first terminal device or is used to identify the UE context of the first terminal device.

26. 26. The communications apparatus of claim 25, wherein the first identifier of the first terminal device comprises one or more of a complete I-RNTI, a complete I-RNTI of the first terminal device, a complete I-RNTI stored on the first terminal device, an I-RNTI, an I-RNTI of the first terminal device, or an I-RNTI stored on the first terminal device.

27. 14. A communication device comprising a processing circuit and an interface circuit, the interface circuit configured to receive a signal from another communication device other than the communication device and transmit the signal to a processor, or to transmit a signal from the processor to another communication device other than the communication device, and the processing circuit configured to implement a method according to any one of claims 1 to 13.

28. 14. A communications device comprising a processor and a storage medium storing instructions for execution by the processor, the instructions, when executed, being configured to cause the communications device to perform a method according to any one of claims 1 to 13.

29. 14. A computer-readable storage medium, the storage medium storing a computer program or instructions, the computer program or the instructions implementing the method of any one of claims 1 to 13 when executed by a communication device.

30. A computer program comprising instructions which, when executed by a computer, cause the computer to carry out the method of any one of claims 1 to 13.

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