Communication methods, terminal device, access network device, readable storage medium, and chip

Abstract

The present application relates to the technical field of communications, and in particular relates to communication methods, a terminal device, an access network device, a readable storage medium, and a chip. A communication method is applied to a non-access stratum (NAS) of a terminal device, and comprises: sending first indication information to an access stratum (AS) of the terminal device, the first indication information being used for indicating a radio resource control (RRC) state when the AS sends a serving cell identifier of the terminal device to the NAS; and receiving the serving cell identifier from the AS, the serving cell identifier being used for determining whether the terminal device is located within a network slice area of service (NS-AoS) of a first network slice, and the first network slice being a network slice configured for the terminal device. In the present application, the AS of the terminal device reports the serving cell identifier to the NAS according to the RRC state indicated by the NAS, thus helping to reduce the power consumption of the terminal device.

Description

Communication method, terminal device, access network device, readable storage medium and chip

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on November 29, 2023, with application number 202311627149.8 and application name “Communication method, terminal equipment, access network equipment, readable storage medium and chip”, the entire contents of which are incorporated by reference in this application. Technical Field

[0002] The present application relates to the field of communication technology, and in particular to a communication method, terminal equipment, access network equipment, readable storage medium and chip. Background Art

[0003] At present, the fifth generation (5G) communication technology supports the provision of customized services for different businesses through network slicing technology to meet different business needs. In order to facilitate the management of network slices, the network slice service area (NS-AoS) is introduced into the network slicing technology. NS-AoS is indicated by the core network device to the terminal device to indicate the service area of ​​a specific network slice, which includes the identification information of one or more cells that can provide services for the network slice. It can be understood that according to the NS-AoS of the network slice, the terminal device can choose to access the appropriate cell and thus use the network slice.

[0004] Since the registration and protocol data unit (PDU) session management processes are decided by the non-access stratum (NAS) of the terminal device, after the introduction of NS-AoS, the NAS of the terminal device needs to determine the position of the serving cell relative to the NS-AoS based on the received NS-AoS of the specific network slice, and then determine the subsequent behavior of the terminal device for the network slice. Therefore, the access stratum (AS) of the terminal device needs to report the serving cell identity to the NAS of the terminal device.

[0005] Summary of the Invention

[0006] The present application provides a communication method, terminal device, access network device, readable storage medium and chip, which are used for the AS of the terminal device to report the serving cell to the NAS of the terminal device according to a specific mechanism, thereby reducing the power consumption of the terminal device.

[0007] In a first aspect, an embodiment of the present application provides a communication method, applied to a NAS of a terminal device, the method comprising: sending first indication information to an AS of the terminal device, the first indication information being used to indicate a radio resource control (RRC) state when the AS sends a serving cell identifier of the terminal device to the NAS; and receiving a serving cell identifier from the AS. The serving cell identifier is used to determine whether the terminal device is located within an NS-AoS of a first network slice, the first network slice being a network slice configured by the network device for the terminal device.

[0008] Exemplarily, the RRC state includes at least one of an RRC connected state, an RRC idle state, and an RRC inactive state.

[0009] Through the communication method provided in this embodiment, the NAS of the terminal device can instruct the AS to report the serving cell identifier to the NAS according to a specific RRC state, thereby avoiding the situation where the AS frequently reports the serving cell identifier to the NAS, and helping to save power consumption of the terminal device.

[0010] In some embodiments, the first indication information further includes a first timer or a first period. The first timer is used to instruct the AS to send a serving cell identifier to the NAS after the first timer expires; the first period is used to instruct the AS to send a serving cell identifier to the NAS according to the first period. In this embodiment, the NAS of the terminal device can control the timing of the AS reporting the serving cell identifier, for example, controlling the AS to report the serving cell identifier after a period of time, or to report the serving cell identifier periodically.

[0011] In some embodiments, the condition for NAS to send the first indication information to AS includes any one of the following conditions 1 to 3.

[0012] Condition 1: NAS supports NS-AoS capability.

[0013] Condition 2: NAS supports NS-AoS capability and receives NS-AoS information of the first network slice of the terminal device within the registration area.

[0014] Condition 3: NAS supports NS-AoS capability and receives NS-AoS information of the first network slice of the terminal device within the registration area, and NAS determines that a registration request for the first network slice needs to be initiated / determined that the user plane of the PDU session associated with the first network slice needs to be activated.

[0015] In this embodiment, the NAS of the terminal device can instruct the AS to report the service cell identifier when supporting the NS-AoS capability and / or when there is a need to use network slicing, so as to avoid the situation where the AS reports uselessly, that is, to avoid the situation where the service cell identifier reported by the AS is not used by the NAS or cannot be used by the NAS.

[0016] In a second aspect, this embodiment provides a communication method, applied to an AS of a terminal device, the method comprising: receiving first indication information from a NAS of the terminal device, and / or receiving second indication information from an access network device; wherein the first indication information is used to indicate that the NAS supports the NS-AoS capability, and the second indication information is used to instruct the AS to send a serving cell identifier of the terminal device to the NAS; and sending the serving cell identifier to the NAS. The serving cell identifier is used to determine whether the terminal device is located within the NS-AoS of a first network slice, where the first network slice belongs to a network slice configured by the network device for the terminal device.

[0017] Through the communication method provided in this embodiment, the AS of the terminal device can report the serving cell identifier to the AS of the terminal device based on the indication information sent by the NAS and / or the access network device. This method clarifies the mechanism for the AS to report the serving cell identifier to the NAS, which helps to save power consumption of the terminal device.

[0018] In some embodiments, the first indication information includes any one of the following indication methods, or a combination of the following multiple indication methods:

[0019] The first indication information is used to instruct the AS to send the serving cell identifier of the terminal device to the NAS.

[0020] The first indication information includes NS-AoS information of the first network slice.

[0021] The first indication information is further used to indicate the RRC state when the AS sends the serving cell identity to the NAS. Exemplarily, the RRC state includes at least one of an RRC connected state, an RRC idle state, and an RRC inactive state.

[0022] In some embodiments, the second indication information includes any one of the following indication methods, or a combination of the following multiple indication methods:

[0023] The second indication information is used to indicate that the service cell of the terminal device is configured with 0 resources for the second network slice, and the second network slice is a network slice supported by the tracking area where the service cell of the terminal device is located.

[0024] The second indication information is used to indicate the RRC state when the AS sends the serving cell identity to the NAS. Exemplarily, the RRC state includes at least one of an RRC connected state, an RRC idle state, and an RRC inactive state.

[0025] In some embodiments, the first indication information and / or the second indication information also includes a first timer or a first period, wherein the first timer is used to instruct the AS to send a serving cell identifier to the NAS after the first timer expires; and the first period is used to instruct the AS to send a serving cell identifier to the NAS according to the first period.

[0026] In this embodiment, the AS may control the timing of reporting the serving cell identity. For example, the AS may report the serving cell identity after a period of time according to a first timer, or periodically report the serving cell identity according to a first period.

[0027] In some embodiments, when the first indication information and / or the second indication information indicates the RRC state when the AS sends the serving cell identity to the NAS, sending the serving cell identity to the NAS includes: sending the serving cell identity to the NAS when the RRC state is met.

[0028] It should be noted that when the RRC states indicated by the first indication information and the second indication information are different, the AS reports the serving cell identifier to the NAS based on the RRC state in the first indication information. Alternatively, the AS reports the serving cell identifier to the NAS based on the RRC state in the second indication information. Alternatively, the AS may determine which indication information to use as the basis for determining the RRC state when reporting the serving cell identifier based on further instructions from the NAS or the access network device.

[0029] In some embodiments, the AS sends the serving cell identifier to the NAS when the RRC status is satisfied, including: if the terminal device does not meet the first condition, the AS sends the serving cell identifier to the NAS when the RRC status is satisfied.

[0030] In some embodiments, the first condition includes the terminal device being in at least one of a capability-limited state, a low power consumption state, and a frequently moving state.

[0031] In a third aspect, this embodiment provides a communication method, applied to an AS of a terminal device, the method comprising:

[0032] receiving first indication information from the NAS of the terminal device, and / or receiving second indication information from the access network device; wherein the first indication information is used to indicate that the NAS supports the NS-AoS capability, and the second indication information is used to instruct the AS to send the serving cell identifier of the terminal device to the NAS; and

[0033] If the terminal device meets the first condition, the serving cell identifier is not sent to the NAS; or

[0034] When the terminal device meets the first condition, the third indication information is sent to the NAS, where the third indication information is used to indicate to the NAS that the AS does not send the serving cell identifier to the NAS; or

[0035] When the terminal device meets the first condition, the serving cell identifier is reported to the NAS according to the second timer or the second period determined by the AS itself.

[0036] The serving cell identifier is used to determine whether the terminal device is located within the NS-AoS of the first network slice, where the first network slice belongs to the network slice configured by the network device for the terminal device. Exemplarily, the first condition includes the terminal device being in at least one of a capability-limited state, a low power consumption state, and a frequently moving state.

[0037] The communication method provided in this embodiment clarifies the mechanism by which the AS reports or does not report the serving cell identifier to the NAS when the terminal device does not meet the first condition.

[0038] In a fourth aspect, this embodiment provides a communication method, applied to an access network device, the method comprising: sending second indication information to a terminal device, the second indication information being used to instruct an AS of the terminal device to send a serving cell identifier to a NAS. The serving cell identifier is used to determine whether the terminal device is located within an NS-AoS of a first network slice, where the first network slice is a network slice configured for the terminal device by the network device.

[0039] Through the method provided in this embodiment, the access network device can instruct the AS to report the serving cell identifier to the NAS, thereby avoiding the situation where the AS frequently reports the serving cell identifier to the NAS, and helping to save power consumption of the terminal device.

[0040] In some embodiments, the second indication information is used to instruct the AS of the terminal device to send the serving cell identifier to the NAS, including any one of the following methods, or a combination of the following multiple indication methods:

[0041] The second indication information is used to indicate that the serving cell of the terminal device is configured with 0 resources for the second network slice, and the second network slice is a network slice supported by the tracking area where the serving cell is located;

[0042] The second indication information is used to indicate the RRC state when the AS sends the serving cell identifier of the terminal device to the NAS. Exemplarily, the RRC state includes at least one of an RRC connected state, an RRC idle state, and an RRC inactive state.

[0043] In some embodiments, the second indication information further includes a first timer or a first period, wherein:

[0044] The first timer is used to instruct the AS to send a serving cell identifier to the NAS after the first timer expires;

[0045] The first cycle is used to instruct the AS to send the serving cell identifier to the NAS according to the first cycle.

[0046] In this embodiment, the access network device can control the timing of the AS reporting the serving cell identifier to the NAS, for example, controlling the AS to report the serving cell identifier after a period of time, or to report the serving cell identifier periodically.

[0047] In some embodiments, the access network device sends the second indication information to the terminal device, including: if the serving cell does not meet the second condition, sending the second indication information to the terminal device. Exemplarily, the second condition includes that the serving cell supports the terminal device in at least one of a capability-limited state, a low power consumption state, and a frequent mobility state.

[0048] In some embodiments, if the serving cell does not meet the second condition, a second indication message is sent to the terminal device, including: if the serving cell does not meet the second condition and the serving cell is configured with 0 resources for the second network slice, a second indication message is sent to the terminal device; wherein the second network slice is a network slice supported by the tracking area TA where the serving cell is located.

[0049] In a fifth aspect, this embodiment provides a communication method, applied to an access network device, the method comprising:

[0050] If the serving cell of the terminal device meets the second condition, the second indication information is not sent to the terminal device, and the second indication information is used to instruct the access layer AS of the terminal device to send the serving cell identifier to the non-access layer NAS of the terminal device; or

[0051] If the serving cell of the terminal device meets the second condition, fourth indication information is sent to the terminal device, and the fourth indication information is used to instruct the AS of the terminal device not to send the serving cell identifier to the NAS.

[0052] The serving cell identifier is used to determine whether the terminal device is located within the NS-AoS of the first network slice, where the first network slice belongs to the network slice configured by the network device for the terminal device. Exemplarily, the second condition includes the serving cell supporting terminal devices in at least one of a capability-limited state, a low power consumption state, and a frequently moving state.

[0053] In a sixth aspect, this embodiment provides a communication method, applied to an access network device, the method comprising:

[0054] Determining that the serving cell does not meet the second condition, and the serving cell of the terminal device is not configured with 0 resources for the first network slice;

[0055] Not sending the second indication information to the terminal device, where the second information is used to instruct the AS of the terminal device to send the serving cell identifier to the NAS; or

[0056] The fourth indication information is sent to the terminal device, and the fourth indication information user instructs the AS of the terminal device not to send the serving cell identifier to the NAS.

[0057] The serving cell identifier is used to determine whether the terminal device is located within the NS-AoS of the first network slice, where the first network slice belongs to the network slice configured by the network device for the terminal device. Exemplarily, the second condition is that the serving cell supports terminal devices in at least one of a capability-limited state, a low-power state, and a frequently moving state.

[0058] In a seventh aspect, this embodiment provides a terminal device, which includes a NAS and an AS, wherein the NAS is configured to perform the various methods shown in the first aspect, and the AS is configured to execute the various methods shown in the second aspect or the third aspect.

[0059] In an eighth aspect, this embodiment provides an access network device, which is configured to execute the various methods shown in the fourth aspect, fifth aspect or sixth aspect above.

[0060] In a ninth aspect, this embodiment provides a communication device configured to perform the method described in any one of aspects 1 to 6 above. The functions of the communication device can be implemented by hardware, or by hardware executing corresponding software implementations. The hardware or software includes one or more units or modules corresponding to the above functions. The units or modules can be software and / or hardware.

[0061] In a tenth aspect, this embodiment provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the method shown in any one of the first to sixth aspects above.

[0062] In the eleventh aspect, this embodiment provides a chip, which includes a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the method shown in any one of the first to sixth aspects above is implemented.

[0063] In a twelfth aspect, this embodiment provides a computer program product, which includes a computer program. When the computer program is executed by a processor, it implements the method shown in any one of the first to sixth aspects above.

[0064] In a thirteenth aspect, this embodiment further provides a communication system, which includes the terminal device as shown in the seventh aspect above, and the access network device as shown in the eighth aspect above.

[0065] It can be understood that the beneficial effects of the seventh to thirteenth aspects can be found in the relevant descriptions of the first to sixth aspects, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] FIG1 is a schematic block diagram of a 5G communication system architecture provided in an embodiment of the present application;

[0067] FIG2 is a schematic diagram of the distribution of cells within a TA provided in an embodiment of the present application;

[0068] FIG3 is a schematic diagram of NS-AoS provided in an embodiment of the present application;

[0069] FIG4 is a schematic flow chart of a communication method provided by an embodiment of the present application;

[0070] FIG5 is a schematic flow chart of a communication method provided in another embodiment of the present application;

[0071] FIG6 is a schematic structural diagram of a communication device 600 provided in one embodiment of the present application;

[0072] FIG7 is a schematic structural diagram of a communication device 700 provided in another embodiment of the present application;

[0073] FIG8 is a schematic structural diagram of a communication device 800 provided in yet another embodiment of the present application. DETAILED DESCRIPTION

[0074] The technical solutions provided in the embodiments of the present application are described below with reference to the accompanying drawings.

[0075] It should be understood that in the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in this article is merely a way to describe the association relationship of associated objects, indicating that three relationships can exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0076] In this embodiment, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this embodiment, unless otherwise specified, "plurality" means two or more.

[0077] An embodiment of the present application provides a communication method, which is applicable to a fifth-generation (5G) communication system, which may also be referred to as a new radio (NR) communication system, or a sixth-generation (6G) communication system, or other future communication systems, future evolved public land mobile networks (PLMNs), and subsequent communication systems supporting third-generation partnership project (3GPP) protocol versions, etc., and the embodiments of the present application are not limited to this.

[0078] The following uses the 5G communication system as an example to illustrate the communication method provided in the embodiment of the present application.

[0079] Figure 1 is a schematic block diagram of the 5G communication system architecture provided by an embodiment of the present application. As shown in Figure 1 , the 5G communication system includes: terminal equipment and network equipment, wherein the network equipment includes access network equipment, core network equipment, and data network (DN). Each of these is described below.

[0080] Terminal devices can connect to the operator's access network equipment via wireless air interfaces, and then connect to the data network through core network equipment. Terminal devices include the AS and NAS. When a terminal device selects a network to connect to, such as the serving cell to access or the network slice to use, the NAS selects the appropriate network based on specific policies and is the decision maker for network selection. The AS searches for the corresponding network using the radio access technology (RAT) and frequency bands supported by the terminal device and is the executor of network selection.

[0081] In this embodiment, the terminal device includes, but is not limited to, user equipment (UE), access terminal device, user unit, user station, mobile station, mobile station, remote station, remote terminal device, mobile device, user terminal device, user agent, or user device, etc. For another example, the terminal device may be a mobile phone, a tablet computer (Pad), a computer with wireless transceiver function, augmented reality (AR) / virtual reality (VR) equipment, a wireless terminal device in industrial control, a wireless terminal device in unmanned driving, a wireless terminal device in telemedicine, a wireless terminal device in smart grid, a wireless terminal device in transportation safety, a wireless terminal device in smart city, a wireless terminal device in smart home, a wireless terminal device in Internet of Vehicles, or a road side unit (RSU) of a wireless terminal device type, etc.

[0082] The access network equipment is mainly used to implement wireless physical layer functions, resource scheduling and wireless resource management, wireless access control, mobility management, etc. In this embodiment, the access network equipment can be an access network (AN) or a radio access network (RAN) equipment.

[0083] In the embodiment of the present application, the access network device includes but is not limited to: an evolved node B (eNB), a radio network controller (RNC), a node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home network device (for example, a home evolved Node B, or a home Node B, HNB), a baseband unit (BBU), an access point (AP) in a wireless fidelity (WIFI) system, a wireless relay node, a wireless backhaul node, a transmission and reception point (TRP), a transmission point (TP), etc.; it can also be a device used in 5G, 6G and other systems, such as a gNB or a transmission point (TRP or TP) in an NR system, one or a group of antenna panels (including multiple antenna panels) of a network device in a 5G system, or a network node constituting a gNB or a transmission point, such as a baseband unit (BBU), or a distributed unit (distributed unit). unit, DU), or vehicle to everything (V2X) or RSU in smart driving scenarios.

[0084] In some deployments, a gNB may include a centralized unit (CU) and a DU. The gNB may also include a radio unit (RU). The CU implements some gNB functions, while the DU implements some gNB functions. For example, the CU implements the functions of the radio resource control (RRC) and packet data convergence protocol (PDCP) layers, while the DU implements the functions of the radio link control (RLC), media access control (MAC), and physical (PHY) layers. Because RRC layer information ultimately becomes PHY layer information, or is converted from PHY layer information, in this architecture, higher-layer signaling, such as RRC layer signaling, can also be considered to be sent by the DU, or by both the DU and the CU. It is understood that a network device can be a CU node, a DU node, or a device that includes both a CU node and a DU node. In addition, the CU can be divided into a network device in an access network (radio access network, RAN), and the CU can also be divided into a network device in a core network (core network, CN), which is not limited in this application.

[0085] In addition, RAN can also be an open access network (open RAN, O-RAN or ORAN). In the ORAN system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU.

[0086] The core network equipment includes functional units such as access and mobility management function (AMF), session management function (SMF), policy control function (PCF), operation, administration and maintenance (OAM). These functional units can work independently or be combined to implement certain control functions. For example, AMF, SMF and PCF can work together to complete access control and mobility management functions such as access authentication, security encryption, and location registration of terminal devices, as well as session management functions such as establishment, release and change of user plane transmission paths, and analysis of some network slice-related data and terminal device-related data. In this embodiment, the core network equipment can implement the above-mentioned network element functions. This embodiment does not limit the specific network element deployment method in the core network equipment.

[0087] Data networks can correspond to a variety of different business areas, such as IP multimedia subsystem (IMS), the Internet, and business areas related to third-party applications. They are mainly used to provide a variety of data business services to terminal devices, which may include devices such as servers (such as third-party application servers), routers, and gateways.

[0088] It should be noted that Figure 1 is only an exemplary architecture diagram of a 5G communication system. In addition to the functional units shown in Figure 1, the network architecture of the 5G communication system may also include other functional units or functional entities, which is not limited in this embodiment.

[0089] With the development of 5G communication technology, a wide range of new services are constantly emerging, and these services often have significantly different requirements for network functionality, connectivity performance, and security. For example, services such as mobile communications, smart homes, environmental monitoring, smart agriculture, and smart metering require networks to support massive device connections and the frequent transmission of large numbers of small messages. Services such as live streaming, video backhaul, and mobile healthcare place even higher demands on transmission speeds. Services such as the Internet of Vehicles, smart grids, and industrial control require millisecond-level latency and near-100% reliability. Understandably, using a single network to carry these services would be difficult to simultaneously meet the diverse requirements of high bandwidth, low latency, and high reliability. Furthermore, building a separate network for each service would incur significant costs. This requires 5G communication systems to be flexible and scalable while also meeting diverse service needs.

[0090] To meet these demands, network slicing technology has emerged. Through network slicing, operators can flexibly allocate network resources and build on-demand networking, enabling them to build multiple dedicated, virtualized, and isolated logical subnets on a common physical network. This allows them to meet the differentiated network capability requirements of different customers and provide targeted services to users.

[0091] In network slicing technology, different logical subnets are identified and distinguished by single network slice selection assistance information (S-NSSAI). Each S-NSSAI includes the following contents (1) to (2):

[0092] (1) Slice / service type (SST), which is used to indicate the specific characteristics and service types of network slices.

[0093] (2) Slice differentiator (SD), as a supplement to SST, can further distinguish multiple network slice instances that meet the same SST; SD is optional.

[0094] It should be noted that for ease of description, NSSAI is generally used to refer to multiple single network slices. In other words, one NSSAI includes multiple S-NSSAIs.

[0095] Regarding NSSAI, the categories involved in this embodiment include the following (1) to (7):

[0096] (1) Subscribed NSSAI, subscribed NSSAI, belongs to the subscription data of the terminal device.

[0097] (2) Configured NSSAI: Configured NSSAI is the NSSAI that the network device configures for the terminal device to use, informing the terminal device which S-NSSAI(s) are available in the network. The network device will bring the Configured NSSAI to the terminal device in the Configured NSSAI information element (IE) of the Registration Accept message. If the configuration of the terminal device changes after registration, the network device can notify the terminal device to update the Configured NSSAI through the Configuration update command. The terminal device will save the Configured NSSAI configured by each network in the non-volatile storage space.

[0098] (3) Requested NSSAI: Requested NSSAI, that is, the NSSAI carried by the terminal device in the Registration Request message.

[0099] (4) Allowed NSSAI: Allowed NSSAI, i.e., the S-NSSAI(s) that the network device determines from the Requested NSSAI that the terminal device is allowed to use based on the terminal device's request. The network device will carry the Allowed NSSAI in the Registration Accept message to the terminal device to inform the terminal device which S-NSSAI(s) in the requested NSSAI are allowed to be used by the network device. Allowed NSSAI is supported within the terminal device's registration area (RA). An RA includes at least one tracking area (TA).

[0100] (5) Rejected NSSAI: Rejected NSSAI refers to the S-NSSAI(s) in the NSSAI requested by the terminal device that are rejected by the network device. For example, when the core network or access network side does not support these S-NSSAI(s), these S-NSSAI(s) are rejected NSSAI.

[0101] (6) Partially Allowed NSSAI: Partially allowed NSSAI is similar to the concept of Allowed NSSAI, except that these S-NSSAI(s) can only be supported by some TAs in the terminal device RA.

[0102] (7) Partially Rejected NSSAI: Partially rejected NSSAI is similar to the concept of rejected NSSAI, except that these S-NSSAI(s) can only be not supported by some TAs in the terminal device RA.

[0103] In 5G communication systems, network slices are not fixed after deployment. Depending on operator needs, some network slices may be decommissioned, while others may be newly deployed. These changes in network slices will affect the configuration of network devices and terminal devices. The details are as follows.

[0104] Currently, network slices are deployed on access network devices based on the TA. This means that all cells within the same TA support the same network slice. When certain network slices become unavailable or unavailable, the Allowed NSSAI and other parameters of the terminal device may change, and consequently, the RA and TA of the terminal device may also need to be changed.

[0105] For example, as shown in Figure 2, the RA of the terminal device includes TA#1. Among them, the Cells deployed by TA#1 include Cell#1, Cell#2, Cell#3 and Cell#4. Since the network slice is deployed according to TA on the access network device side, Cell#1 to Cell#4 in TA#1 support the same network slice, such as network slice 2 (which can be expressed as Slice#2). Take the example that the network device allows the terminal device to use Slice#2, that is, the Allowed NSSAI of the terminal device is Slice#2. It can be understood that the terminal device can use Slice#2 by accessing any Cell from Cell#1 to Cell#4.

[0106] However, during the Slice#2 service process, due to network deployment changes and other reasons, the resources allocated to Slice#2 by Cell#2 in TA#1 are suddenly restricted. For example, Cell#2 suddenly withdraws any resources configured for Slice#2, resulting in Cell#2 being unable to actually provide Slice#2 services to the terminal device. It can be understood that if the terminal device is connected to Cell#2 in TA#1, then Slice#2 is actually unable to provide services to the terminal device, and the terminal device may experience network connection failures, resulting in a poor user experience. To avoid the above situation, in some implementations, the network device can readjust the deployment of RA and TA, and allocate a new Allowed NSSAI for the terminal device. However, this process is complicated, costly, and not easy to promote and use.

[0107] To this end, 3GPP introduced the concept of NS-AoS. NS-AoS is used to indicate the service area for a specific network slice. NS-AoS includes one or more cell identifiers, such as the NR cell global identifier (NCGI), physical cell identifier (PCI), etc. When a terminal device uses a network slice, it can select a cell that can provide services for the network slice based on the NS-AoS of the network slice to access, avoiding the situation where the network slice cannot be used.

[0108] After the introduction of NS-AoS, as shown in Figure 2, if all cells within TA#1 support Slice#2, then Slice#2's service area within TA#1 includes Cell#1, Cell#2, Cell#3, and Cell#4. If the resources allocated to Slice#2 by Cell#2 within TA#1 are suddenly limited, then, for example, as shown in Figure 3, Slice#2's service area will not include Cell#2, that is, Slice#2's NS-AoS includes Cell#1, Cell#3, and Cell#4. Based on this, when using Slice#2, the terminal device can select a cell that supports Slice#2 for access based on Slice#2's NS-AoS, thereby avoiding the situation where Slice#2 cannot be used.

[0109] NS-AoS is deployed on the RAN side, and the AMF of the network device can obtain the NS-AoS configured for each network slice in the RA of the terminal device through OAM. In addition, when the terminal device indicates that it supports S-NSSAI location availability information (S-NSSAI location availability information), the AMF will send the NS-AoS for Configured NSSAI in the RA to the terminal device through a registration receive message (Registration Accept) or a UE configuration update message (UE Configuration Update). Among them, the terminal device's support for S-NSSAI location availability information can be interpreted as the terminal device being able to parse the S-NSSAI location availability information.

[0110] After the network device configures NS-AoS for a network slice, since NS-AoS may include some cells within the TA or all cells within the TA, the serving cell of the terminal device may be located within or outside the NS-AoS. Depending on the relative position between the terminal device and the NS-AoS, the terminal device and the network device can perform the following operations:

[0111] Operation 1: If the terminal device receives an NS-AoS for a Requested NSSAI, then after the terminal device initiates a registration request for the network slice outside the NS-AoS, the network slice will be determined by the AMF as an Allowed NSSAI or Partially Allowed NSSAI. For example, as shown in Figure 3, if the terminal device initiates a registration request for Slice#2 to the network device while connected to Cell#2, since the terminal device is outside the NS-AoS of Slice#2, that is, the terminal device has a need to use Slice#2, then Slice#2 will be determined by the AMF as an Allowed NSSAI or Partially Allowed NSSAI so that the terminal device can use Slice#2.

[0112] Operation 2: If the terminal device receives an NS-AoS for a Rejected NSSAI or a Partially Rejected NSSAI, the terminal device can only initiate registration requests for these network slices in cells within the NS-AoS range of the above network slices. Taking the NS-AoS for Rejected NSSAI as an example, the terminal device can only initiate registration requests for the network slices corresponding to Cell#5 and Cell#6 when connected to Cell#5 or Cell#6.

[0113] Operation 3: If the terminal device receives an NS-AoS for Allowed NSSAI or Partially Allowed NSSAI, the terminal device can only activate the user plane for the established PDU session within the NS-AoS range of the above network slice.

[0114] Since the registration and PDU session management processes are decided by the NAS of the terminal device, after the introduction of NS-AoS, the NAS of the terminal device needs to determine the position of the serving cell relative to the NS-AoS based on the received NS-AoS of the specific network slice, and then determine the subsequent behavior of the terminal device for the network slice.

[0115] Currently, a terminal device determines its serving cell by having the AS report the serving cell identifier to the NAS. Based on the serving cell identifier, the NAS determines which serving cell the terminal device is located in. Understandably, if the AS of a terminal device frequently and unconditionally reports the serving cell identifier, this will result in significant power consumption for the terminal device. Therefore, a clear triggering mechanism for terminal devices to report the serving cell identifier is needed.

[0116] To this end, an embodiment of the present application provides a communication method, which involves a process in which a terminal device AS reports a service cell identifier according to instructions from the terminal device's NAS and / or access network device, thereby avoiding the terminal device's AS from frequently reporting the service cell identifier to the terminal device's NAS, and reducing the power consumption of the terminal device.

[0117] Figure 4 is a schematic flow chart of a communication method provided by an embodiment of the present application. The method involves a process in which the AS of a terminal device reports a serving cell identity according to an instruction of a NAS. Taking the terminal device as a UE as an example, the method specifically includes the following steps.

[0118] S401: UE NAS determines that it meets the triggering condition.

[0119] In S401, the UE NAS determines that it meets the triggering conditions, which is mainly used to determine whether the UE NAS supports the NS-AoS capability and / or has the need to use network slicing. Based on this, the triggering conditions may include the following situations.

[0120] In some embodiments, the trigger condition is that the NAS determines that it supports the NS-AoS capability. For example, if the UE NAS indicates support for S-NSSAI location availability information in the 5G Mobility Management Core Network Capability (5GMM Core Network Capability) information element of the uplink NAS message, it indicates that the UE supports the NS-AoS capability.

[0121] In some other embodiments, the trigger condition is: the NAS determines that it supports the NS-AoS capability and receives the S-NSSAI location availability information of the first network slice of the UE in the RA. The S-NSSAI location availability information includes the S-NSSAI and its corresponding NS-AoS information.

[0122] In some further embodiments, the trigger condition is: NAS determines that it supports NS-AoS capability, and receives S-NSSAI location availability information of the first network slice of the UE within the RA, and NAS also determines that a registration request for the first network slice needs to be initiated / determined that the user plane of the PDU session associated with the first network slice needs to be activated.

[0123] It should be noted that the first network slice belongs to the Configured NSSAI of the UE. For example, when the UE is in the RRC idle state or the RRC inactive state, the first network slice may be the network slice that the UE requests to use from the network device. Alternatively, when the UE is in the RRC connected state, the first network slice may be the network slice corresponding to the service that the UE is currently performing, or the network slice corresponding to the service that the UE is about to request.

[0124] S402: UE NAS sends first indication information to UE AS.

[0125] In this embodiment, the first indication information is used to indicate that the UE NAS supports the NS-AoS capability, so that the UE AS sends a serving cell identifier to the UE NAS according to the first indication information. Based on the serving cell identifier, the UE NAS can determine whether the UE is located within the NS-AoS of the first network slice, and further determine the subsequent behavior of the UE.

[0126] It should be noted that "indicating that the UE NAS supports the NS-AoS capability" is a function or effect that can be achieved by the first indication information, and this embodiment does not limit the specific indication form of the first indication information.

[0127] In some embodiments, the first indication information directly indicates that the UE NAS supports the NS-AoS capability, for example, the UE NAS sends a related indication field to the UE AS. After receiving the indication field, the UE AS considers that the UE NAS supports the NS-AoS capability.

[0128] In some other embodiments, the first indication information indirectly indicates that the UE NAS supports the NS-AoS capability. For details, see Examples 1 to 4.

[0129] Example 1: The first indication information is used to instruct the UE AS to send the UE's serving cell identifier to the UE NAS.

[0130] Example 2: The first indication information includes NS-AoS information of the first network slice.

[0131] In Example 3, the first indication information is used to indicate the RRC state when the UE AS reports the UE's serving cell identity to the UE NAS, that is, the target RRC state. Exemplarily, the target RRC state can be at least one of an RRC connected state (RRC_CONNECTED), an RRC idle state (RRC_IDLE), and an RRC inactive state (RRC_INACTIVE).

[0132] In Example 4, the first indication information includes a first timer or a first period, where the first timer or the first period is used to control the timing at which the UE AS reports the serving cell identifier to the UE NAS. For example, based on the first timer, the UE AS can be controlled to report the serving cell identifier to the UE NAS after the first timer expires, rather than immediately. For another example, based on the first period, the UE AS can be controlled to report the serving cell identifier to the UE NAS once every period of time, so that the UE NAS can promptly update the serving cell identifier after the UE's serving cell changes.

[0133] It should be noted that the first indication information may also include the above-mentioned direct indication content and one or more of the indirect indication content. For example, the first indication information simultaneously indicates "UE NAS supports NS-AoS capability" and "target RRC state". Alternatively, the first indication information simultaneously indicates "UE NAS supports NS-AoS capability" and "sending the UE's serving cell identifier to the UE NAS". Alternatively, the first indication information simultaneously indicates "UE NAS supports NS-AoS capability", "sending the UE's serving cell identifier to the UE NAS", and "first timer / first period".

[0134] In addition, the first indication information may also include multiple indirect indication contents simultaneously. For example, the first indication information may simultaneously indicate "sending the UE's serving cell identifier to the UE NAS" and "target RRC state." Alternatively, the first indication information may simultaneously indicate "sending the UE's serving cell identifier to the UE NAS" and "a first timer / first period."

[0135] The three RRC states involved in this embodiment are explained below respectively.

[0136] RRC_CONNECTED: This refers to the RRC connected state. If the terminal device has established an RRC connection with the network device, the terminal device is in the RRC connected state. In the RRC connected state, the terminal device can establish a user plane and control plane connection with the network device, and the terminal device can transmit user plane data and control plane signaling with the network device through the first terminal device.

[0137] RRC_IDLE: This refers to the RRC idle state. If the terminal device has not established an RRC connection with the network device, the terminal device is in the RRC idle state. In the RRC idle state, the terminal device can perform operations such as PLMN selection and cell reselection.

[0138] RRC_INACTIVE: that is, RRC inactive state. The terminal device has no need to transmit data with the network device within the preset time period in the RRC connected state. The network device can determine that the terminal device has entered the RRC inactive state. The network device can send an RRC release (RRCRelease with suspend indication) message carrying a suspension indication to the terminal device. After the terminal device receives the RRCRelease with suspend indication message, the terminal device retains its own context and enters the RRC inactive state.

[0139] S403: The UE AS reports the serving cell identifier to the UE NAS.

[0140] After receiving the first indication information, the UE AS may, as shown in S403a, report the serving cell identifier to the UE NAS directly based on the first indication information, regardless of the UE's capabilities and status. Alternatively, as shown in S403b1-S403b2, the UE AS may report the serving cell identifier to the UE NAS based on the UE's capabilities and status, combined with the first indication information. Each of these is described below.

[0141] First, in conjunction with S403a, an exemplary description is given of a process in which the UE AS reports the serving cell identity to the UE NAS according to the instruction of the first indication information without considering the capability and status of the UE itself.

[0142] S403a: The UE AS directly reports the serving cell identity to the UE NAS.

[0143] In this embodiment, the specific process of the UE AS reporting the serving cell identity to the UE NAS is generally different according to the specific content of the first indication information, as shown below.

[0144] For example, if the first indication information is only used to indicate that the UE NAS supports the NS-AoS capability, then after receiving the first indication information, the UE AS immediately reports the serving cell identity to the UE NAS.

[0145] For another example, if the first indication information is used not only to indicate that the UE NAS supports the NS-AoS capability but also to indicate the RRC state when the UE AS reports the serving cell identity to the UE NAS, that is, the target RRC state, then after receiving the first indication information, the UE AS must report the serving cell identity to the UE NAS when the target RRC state is met. For example, if the target RRC state is the RRC connected state, after receiving the first indication information, the UE AS must report the serving cell identity to the UE NAS in the RRC connected state.

[0146] For another example, if the first indication information is used not only to indicate that the UE NAS supports the NS-AoS capability but also to indicate a first timer or a first period, then, after receiving the first indication information, the UE AS reports the serving cell identity to the UE NAS after the first timer expires, or reports the serving cell identity to the UE NAS once every period of time according to the first period.

[0147] For another example, if the first indication information is used to indicate that the UE NAS supports the NS-AoS capability and is used to indicate the target RRC state when the UE AS reports the serving cell identity to the UE NAS, and is also used to indicate the first timer or the first period, then after receiving the first indication information, the UE AS needs to report the serving cell identity to the UE NAS after the first timer expires and when the UE meets the target RRC state; or, report the serving cell identity to the UE NAS once every period of time according to the first period when the UE meets the target RRC state.

[0148] In the following, with reference to S403b1 to S403b2, the process in which the UE AS reports the serving cell identity to the UE NAS according to the capability and status of the UE itself and the instruction of the first indication information is exemplified.

[0149] S403b1, the UE AS determines whether the UE meets the first condition.

[0150] In this embodiment, the first condition includes: the UE is in at least one of a capability-limited state, a low power consumption state, and a frequently moving state. For example, the UE being in a capability-limited state includes: the UE using the capability-limited RedCap technology. The UE being in a low power consumption state includes: the UE enabling energy-saving mode, and / or the UE connecting to the narrowband Internet of Things NB-IoT. The UE being in a frequently moving state includes: the UE accessing a mobile access and backhaul integrated (IAB) cell; or the UE accessing a high-speed dedicated network (HSDN) cell.

[0151] S403b2: When the UE does not meet the first condition, the UE AS reports the serving cell identifier to the UE NAS.

[0152] In other words, when reporting the serving cell ID to the UE NAS, the UE AS needs to consider the UE's own capabilities or the UE's mobility status to avoid wasted power consumption or reporting failures. For example, the UE AS needs to avoid reporting the serving cell ID when the UE is in a low-power state, which would waste UE power consumption; or, the UE AS needs to avoid reporting the serving cell ID when the UE's capabilities are limited, which would cause reporting failures; or, the UE AS needs to avoid frequently reporting the serving cell ID when the UE is moving rapidly, which would waste power consumption.

[0153] It should be noted that, in S403b2, after the UE AS determines to report the serving cell identity to the UE NAS according to the first condition, the specific reporting process can be found in S403a and will not be described again here.

[0154] It is understandable that the UE may also meet the first condition, that is, the UE may be in at least one of a capability-limited state, a low power consumption state, and a frequently moving state.

[0155] When the UE meets the first condition, the UE AS does not report the serving cell identifier to the UE NAS, or the UE AS sends an indication message to the UE NAS, such as a third indication message, and the third indication message is used to indicate to the UE NAS that the UE AS does not report the serving cell identifier to the UE NAS. Alternatively, when the UE meets the first condition, the UE AS still reports the serving cell identifier to the UE NAS, but the reporting time or period can be determined by the UE AS based on its own capabilities. For example, the UE AS reports the serving cell identifier to the UE NAS based on a second timer or a second period. The second period can be determined with reference to the UE's discontinuous reception (DRX) period, for example, the second period is the same as the DRX period. In addition, the UE AS can also notify the UE NAS of the second timer or the second period so that the UE AS and the UE NAS understand synchronization.

[0156] For example, if the UE AS receives the first indication information from the UE NAS when the UE is in a low power state, and because it needs to save power or has entered a sleep state, the UE AS may choose not to report the serving cell identity to the UE NAS to avoid wasting power.

[0157] For another example, if the UE is in a capability-limited state and the UE AS receives the first indication information from the UE NAS, and the UE capability limitation may not support the use of network slicing, the UE AS will not report the service cell identifier to the UE NAS.

[0158] For another example, if the UE is in a frequently moving state, for example, the UE is a vehicle-mounted UE, and the vehicle-mounted UE is connected to a mobile IAB cell, that is, the UE's service cell is a mobile IAB cell. Since the mobile IAB node is set on the vehicle, the vehicle-mounted UE moves with the mobile IAB node, and the vehicle-mounted UE and the service cell are relatively stationary. In this case, although the NCGI of the service cell will be frequently updated due to the mobility of the mobile IAB node, the physical cell to which the vehicle-mounted UE is actually connected has not changed. Therefore, the UE AS does not need to report the service cell identifier to the UE NAS every time the service cell changes the NCGI. Based on this, after receiving the first indication information, the UE AS may not report the service cell identifier; or, the UE AS may decide the reporting strategy on its own, for example, the service cell identifier will no longer be reported after the UE AS reports it once, until the UE gets off the vehicle and changes the service cell.

[0159] Alternatively, when the UE is in a high-mobility state, the UE AS may determine not to report the serving cell identifier temporarily until the mobility state is no longer high-mobility. This is because the UE may frequently perform cell reselection or handover in a high-mobility state, resulting in frequent changes in the serving cell. In this case, if the UE AS reports the serving cell identifier, it will not only increase the UE's power consumption, but even if the UE AS reports the serving cell identifier, the information reported by the UE AS may not be timely due to the high-mobility state, affecting the accuracy of the UE's subsequent behavior.

[0160] In summary, through the communication method provided in this embodiment, the UE AS can report the serving cell identifier to the UE AS according to the instructions of the UE NAS, for example, according to the target RRC state, the first timer, the first period, etc. indicated by the UE NAS, and clarifies the mechanism for the UE AS to report the serving cell identifier to the UE NAS, which helps to save the power consumption of the UE.

[0161] Figure 5 is a schematic flow chart of a communication method provided by another embodiment of the present application. The method involves a process in which an AS of a terminal device reports a serving cell identifier according to an instruction of an access network device. Taking the terminal device as a UE as an example, the method specifically includes the following steps.

[0162] S501: The access network device sends second indication information to the UE AS.

[0163] In this embodiment, the second indication information is used to instruct the UE AS to send a serving cell identifier to the UE NAS, so that the UE NAS determines whether the UE is located in the NS-AoS of the first network slice based on the serving cell identifier. The relevant description of the first network slice can be found in the previous text and will not be repeated here.

[0164] In this embodiment, the access network device may send the second indication information to the UE via broadcast or RRC dedicated signaling. For example, a UE in an RRC idle state or an RRC inactive state may receive the second indication information via broadcast, and a UE in an RRC connected state may receive the second indication information via RRC dedicated information, such as an RRC reconfiguration message.

[0165] It should be noted that "instructing the UE AS to send a serving cell identity to the UE NAS" is an indication function or effect that can be achieved by the second indication information, and this embodiment does not limit the specific form of the second indication information.

[0166] In some embodiments, the second indication information directly instructs the UE AS to send the serving cell identifier to the UE NAS. For example, the access network device sends a related indication field to the UE AS, and after receiving the indication field, the UE AS determines that the access network device instructs the UE AS to send the serving cell identifier to the UE NAS.

[0167] In some other embodiments, the second indication information indirectly instructs the UE AS to send the serving cell identity to the UE NAS. For details, see Examples A to C.

[0168] In Example A, the second indication information is used to indicate that the UE's serving cell is configured with zero resources for the second network slice. The second network slice is a network slice supported by the TA in which the UE's serving cell is located. For example, as shown in Figure 3, when the UE's serving cell is Cell#2, Cell#2 is located in TA#1, and Slice#2 supported by TA#1 is the second network slice. In this case, the second indication information is used to indicate that the UE's serving cell Cell#2 is configured with zero resources for the second network slice Slice#2, or it can be understood that no resources are allocated.

[0169] In example B, the second indication information is used to indicate the RRC state that needs to be satisfied when the UE AS sends the serving cell identity to the UE NAS, that is, the target RRC state. Exemplarily, the target RRC state can be at least one of an RRC connected state, an RRC idle state, and an RRC inactive state.

[0170] In Example C, the second indication information includes a first timer or a first period, wherein the first timer is used to instruct the UE AS to send the serving cell identifier to the UE NAS after the first timer expires, and the first period is used to instruct the UE AS to send the serving cell identifier to the UE NAS according to the first period.

[0171] It should be noted that the second indication information may also include the above-mentioned direct indication content and one or more of the indirect indication content. For example, the second indication information may simultaneously indicate "UE AS sends the serving cell identifier to UE NAS" and "target RRC state." Alternatively, the second indication information may simultaneously indicate "UE AS sends the serving cell identifier to UE NAS" and "first timer / first period." This embodiment is not limited to this.

[0172] In addition, the second indication information may also include multiple indirect indication contents simultaneously. For example, the second indication information may simultaneously indicate "the UE's serving cell is configured with 0 resources for the second network slice" and "the target RRC state." Alternatively, the second indication information may simultaneously indicate "the target RRC state" and "the first timer / first period."

[0173] In S501, the access network device sends the second indication information to the UE AS, which can be implemented in the following manner.

[0174] In some embodiments, the access network device directly sends the second indication information to the UE AS, that is, when sending the second indication information to the UE AS, the access network device does not determine whether the second indication information should be sent to the UE AS.

[0175] In other embodiments, when the UE's serving cell does not meet the second condition, the access network device sends second indication information to the UE AS. The second condition includes: the UE's serving cell supports UEs in at least one of a capability-limited state, a low-power state, and a frequent mobility state. For example, the UE's serving cell is a mobile IAB cell, an NB-IoT cell, or an HSDN cell. The specific details of the capability-limited state, low-power state, and frequent mobility state are described above and are not further described here.

[0176] In some further embodiments, when the UE's serving cell is configured with 0 resources for the second network slice, the access network device sends second indication information to the UE AS. In addition, if the UE's serving cell is not configured with 0 resources for the second network slice, the access network device does not send the second indication information to the UE AS, or the access network device does not perform any related indications, or the access network device may also send indication information to the UE AS, such as fourth indication information, to instruct the UE AS not to send the serving cell identifier to the UE NAS.

[0177] In some other embodiments, when the UE's serving cell does not meet the second condition, the access network device may further determine whether the UE's serving cell is configured with 0 resources for the second network slice. If the UE's serving cell is configured with 0 resources for the second network slice, it means that the UE's serving cell cannot provide the UE with the service of the second network slice. At this time, the access network device sends a second indication message to the UE AS. If the UE's serving cell is not configured with 0 resources for the second network slice, it means that the UE's serving cell can provide the UE with the service of the second network slice. At this time, the access network device does not send the second indication message to the UE AS, or the access network device does not make any relevant indications, or the access network device may also send an indication message to the UE AS to instruct the UE AS not to send the serving cell identifier to the UE NAS, such as the fourth indication message.

[0178] Of course, there may also be cases where the UE meets the second condition. Specifically, when the UE meets the second condition, for example, when the UE's serving cell is a mobile IAB cell, an NB-IoT cell, or an HSDN cell, in order to avoid wasting UE power consumption, the access network device may not send the second indication information to the UE AS, or the access network device may not perform any relevant indications, or the access network device may also send indication information, such as the fourth indication information, to the UE AS, instructing the UE AS not to send the serving cell identifier to the UE NAS.

[0179] In addition, optionally, for a UE in an RRC connected state, the access network device may decide on its own whether to send the second indication information to the UE AS, or may send the second indication information to the UE AS according to the instruction of the core network device. For example, the AMF of the core network device may determine whether the UE is located outside the NS-AoS of the second network slice based on the location of the UE, and then decide whether to instruct the access network device to send the second indication information or the fourth indication information to the UE AS. Among them, the judgment logic of the AMF in deciding whether to instruct the access network device to send the second indication information or the fourth indication information to the UE AS can refer to the judgment logic of the access network device itself in determining whether to send the second indication information or the fourth indication information to the UE AS, and will not be repeated here.

[0180] S502: UE AS reports the serving cell identity to UE NAS.

[0181] After receiving the second indication information, the UE AS may, as shown in S502a, report the serving cell identifier to the UE NAS directly based on the second indication information, regardless of the UE's own capabilities and status. Alternatively, as shown in S502b1 to S502b2, the UE AS may report the serving cell identifier to the UE NAS based on the UE's own capabilities and status, combined with the instructions in the second indication information.

[0182] First, in conjunction with S502a, an exemplary description is given of a process in which the UE AS reports the serving cell identity to the UE NAS according to the instruction of the second indication information without considering the capability and status of the UE itself.

[0183] S502a: The UE AS directly reports the serving cell identity to the UE NAS.

[0184] In this embodiment, the specific process of the UE AS reporting the serving cell identity to the UE NAS is generally different according to the specific content of the second indication information, as shown below.

[0185] For example, if the second indication information is only used to instruct the UE AS to report the serving cell identifier to the UE NAS, then after receiving the second indication information, the UE AS immediately reports the serving cell identifier to the UE NAS.

[0186] For another example, if the second indication information, in addition to instructing the UE AS to report the serving cell identifier to the UE NAS, is also used to instruct the UE AS to use the RRC state (i.e., the target RRC state) when reporting the serving cell identifier to the UE NAS, then, after receiving the second indication information, the UE AS must report the serving cell identifier to the UE NAS if the target RRC state is satisfied. For example, if the target RRC state is the RRC connected state, after receiving the second indication information, the UE AS must report the serving cell identifier to the UE NAS in the RRC connected state.

[0187] For another example, if the second indication information, in addition to instructing the UE AS to report the serving cell identifier to the UE NAS, further includes a first timer or a first period, then, after receiving the first indication information, the UE AS reports the serving cell identifier to the UE NAS after the first timer expires, or reports the serving cell identifier to the UE NAS once every period of time according to the first period.

[0188] For another example, if the second indication information, in addition to being used to instruct the UE AS to report the serving cell identifier to the UE NAS and instructing the UE AS to report the target RRC state when reporting the serving cell identifier to the UE NAS, also includes a first timer or a first period, then after receiving the second indication information, the UE AS needs to report the serving cell identifier to the UE NAS after the first timer expires and when the UE satisfies the target RRC state, or report the serving cell identifier to the UE NAS once at intervals according to the first period when the UE satisfies the target RRC state.

[0189] In the following, with reference to S502b1 to S502b2, the process in which the UE AS reports the serving cell identity to the UE NAS according to the capability and status of the UE itself and the instruction of the second indication information is exemplified.

[0190] S502b1, the UE AS determines whether the UE meets the first condition.

[0191] S502b2: When the UE does not meet the first condition, the UE AS reports the serving cell identifier to the UE NAS.

[0192] It should be noted that, for S502b1 to S502b2, please refer to S403b1 to S403b2 for details, which will not be repeated here.

[0193] In addition, if the UE determines that it meets the first condition, the UE AS does not report the serving cell identifier to the UE NAS. Alternatively, the UE AS sends an indication message, such as third indication message, to the UE NAS, indicating that the UE AS does not report the serving cell identifier to the UE NAS. Alternatively, when the UE meets the first condition, the UE AS still reports the serving cell identifier to the UE NAS, but the reporting time or period may be determined by the UE AS based on its own capabilities. For details, see the above description.

[0194] In summary, through the communication method provided in this embodiment, the UE AS can report the serving cell identifier to the UE AS based on the instruction of the access network device, such as the target RRC state, the first timer, the first period, etc. indicated by the access network device. This method clarifies the mechanism for the UE AS to report the serving cell identifier to the UE NAS, which helps to save UE power consumption.

[0195] It should be noted that because the process of the UE NAS sending the first indication information to the UE AS and the process of the access network device sending the second indication information to the UE AS are independent of each other, the UE AS may receive both the first indication information and the second indication information. Furthermore, the first indication information and the second indication information may indicate the same or different content, or even have opposite indication effects. In this case, the UE AS can use the following method to report the serving cell identity to the UE NAS.

[0196] In some embodiments, the UE AS receives both the first indication information from the UE NAS and the second indication information from the access network device. Then, the UE AS reports the serving cell identifier to the UE NAS according to the second indication information from the access network device.

[0197] For example, the UE AS receives both the first indication information including the first timer (e.g., 2S (seconds)) from the UE NAS and the second indication information including the first timer (e.g., 1S) from the access network device. Then, the terminal device reports the service cell identifier to the UE NAS according to the first timer indicated by the second indication information, e.g., 1S.

[0198] For another example, if the UE AS receives first indication information from the UE NAS instructing it to report the serving cell identifier to the UE NAS in the RRC connected state, and also receives second indication information from the access network device instructing it to report the serving cell identifier to the UE NAS in the RRC connected state and the RRC inactive state, then the UE AS shall report the serving cell identifier to the UE NAS in the RRC connected state and the RRC inactive state based on the second indication information.

[0199] For another example, the UE AS receives both first indication information from the UE NAS instructing it to report the serving cell identifier to the UE NAS and fourth indication information from the access network device instructing it not to report the serving cell identifier to the UE NAS (see above). In this case, the UE AS does not report the serving cell identifier to the UE NAS based on the fourth indication information from the access network device.

[0200] For another example, the UE AS may receive both the third indication information from the UE NAS indicating not to report the serving cell identifier to the UE NAS (see above), and the second indication information from the access network device indicating to report the serving cell identifier to the UE NAS. In this case, the UE AS reports the serving cell identifier to the UE NAS based on the second indication information from the access network device.

[0201] It should be noted that, after the UE AS determines to report the serving cell identity to the UE NAS according to the second indication information, the process shown in step S403 may be referred to, which will not be described in detail here.

[0202] In other embodiments, the UE AS receives both the first indication information from the UE NAS and the second indication information from the access network device. The UE AS then reports the serving cell identifier to the UE NAS based on the first indication information from the UE NAS. The specific process of the UE AS reporting the serving cell identifier to the UE NAS can be found in step S403 and is not further described here.

[0203] In some other embodiments, when the UE NAS sends the first indication information to the UE AS, and / or when the access network device sends the second indication information to the UE AS, the UE AS may further instruct the UE AS which indication information to use when receiving multiple conflicting indication information. For example, when the UE NAS sends the first indication information to the UE AS, it may also send fifth indication information to the UE AS, where the fifth indication information is used to instruct the UE AS to use the indication of the UE NAS or the indication of the access network device as the basis after receiving the conflicting indication information.

[0204] Through the communication method provided in the embodiment of the present application, the UE AS can report the serving cell identifier to the UE AS according to the instructions of the UE NAS and / or the access network device, thereby avoiding the situation where the UE AS frequently and unconditionally reports the serving cell identifier, which helps to save the power consumption of the UE.

[0205] It should be noted that in the above embodiments, the descriptions of each embodiment have their own emphasis. To avoid redundancy, for parts not described in detail in one embodiment, reference can be made to the relevant descriptions of other embodiments. In addition, it should be understood that the order of the sequence numbers of the steps in the above embodiments does not imply a sequence of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0206] Based on the same inventive concept, as an implementation of the above method, this embodiment also provides the following technical solution.

[0207] An embodiment of the present application further provides a terminal device, which includes a NAS and an AS, wherein the NAS and the AS are respectively configured to execute the methods executed by the NAS and the AS correspondingly in the above embodiments.

[0208] This embodiment provides an access network device, which is configured to perform the method performed by the access network device in the above embodiment.

[0209] This embodiment provides a communication device, which is configured to execute the method executed by the NAS, AS or access network device in the above embodiments.

[0210] FIG6 is a schematic diagram of the structure of a communication device provided by an embodiment of the present application. The communication device is applied to a NAS of a terminal device, and specifically includes a sending unit 601 and a receiving unit 602.

[0211] The sending unit 601 is used to send first indication information to the AS of the terminal device, where the first indication information is used to indicate the RRC state when the AS sends the serving cell identifier of the terminal device to the NAS.

[0212] The receiving unit 602 is configured to receive a serving cell identifier from an AS.

[0213] Among them, the service cell identifier is used to determine whether the terminal device is located in the network slice service area NS-AoS of the first network slice, and the first network slice belongs to the configured network slice of the terminal device.

[0214] In some embodiments, the first indication information further includes a first timer or a first period, wherein the first timer is used to instruct the AS to send the serving cell identifier to the NAS after the first timer expires, and the first period is used to instruct the AS to send the serving cell identifier to the NAS according to the first period.

[0215] In some embodiments, the conditions for the NAS to send the first indication information to the AS include:

[0216] NAS supports NS-AoS capability; or,

[0217] The NAS supports the NS-AoS capability and receives the NS-AoS information of the first network slice of the terminal device in the registration area; or,

[0218] NAS supports NS-AoS capability and receives NS-AoS information of the first network slice of the terminal device within the registration area, and NAS determines that a registration request for the first network slice needs to be initiated / determined that the user plane of the PDU session associated with the first network slice needs to be activated.

[0219] FIG7 shows a communication device 700 provided by another embodiment of the present application. The communication device 700 is applied to the access layer AS of a terminal device, and includes a receiving unit 701 and a sending unit 702 .

[0220] The receiving unit 701 is used to receive first indication information from the non-access stratum NAS of the terminal device, and / or receive second indication information from the access network device; wherein the first indication information is used to indicate that the NAS supports the network slice service area NS-AoS capability, and the second indication information is used to indicate that the AS sends the service cell identifier of the terminal device to the NAS.

[0221] The sending unit 702 is configured to send a serving cell identifier to the NAS.

[0222] Among them, the service cell identifier is used to determine whether the terminal device is located in the NS-AoS of the first network slice, and the first network slice belongs to the configured network slice of the terminal device.

[0223] Optionally, the sending unit 702 is further configured to send a serving cell identifier to the NAS when the RRC status is met.

[0224] Optionally, the sending unit 702 is further used to send the serving cell identifier to the NAS if the terminal device does not meet the first condition and the RRC state is met.

[0225] It should be noted that, in the device provided in this embodiment, the specific contents of the first indication information and the second indication information are referred to above and will not be repeated here.

[0226] FIG8 shows a communication device 800 provided by another embodiment of the present application. The communication device 800 is applied to an access network device and includes a receiving and sending unit 801.

[0227] A sending unit 801 is configured to send second indication information to a terminal device, where the second indication information is used to instruct an access stratum (AS) of the terminal device to send a serving cell identifier to a non-access stratum (NAS) of the terminal device. The serving cell identifier is used to determine whether the terminal device is located within a network slice service area (NS-AoS) of a first network slice, where the first network slice belongs to a configured network slice of the terminal device.

[0228] Optionally, the sending unit 801 is further used to send second indication information to the terminal device if the service cell of the terminal device does not meet the second condition.

[0229] Optionally, the sending unit 801 is also used to send a second indication message to the terminal device if the serving cell does not meet the second condition and the serving cell is configured with 0 resources for the second network slice; wherein the second network slice is a network slice supported by the TA where the serving cell is located.

[0230] In this embodiment, the second condition includes: the serving cell supports terminal devices in at least one of a capability-limited state, a low power consumption state, and a frequent movement state.

[0231] It should be noted that the specific content of the second indication information in the device provided in this embodiment is referred to above and will not be repeated here.

[0232] This embodiment provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the method performed by the NAS, AS, or access network device in the above embodiment is implemented.

[0233] An embodiment of the present application further provides a chip, which includes a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the method performed by the NAS, AS or access network device in the above embodiment is implemented.

[0234] An embodiment of the present application further provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the method performed by the NAS, AS or access network device in the above embodiment is implemented.

[0235] An embodiment of the present application further provides a computer program product, which includes a computer program. When the computer program is executed by an electronic device, the electronic device implements the method performed by the NAS, AS or access network device in the above embodiment.

[0236] This embodiment further provides a communication system, which includes the terminal device shown in the above embodiment and the access network device shown in the above embodiment.

[0237] It should be understood that the processor mentioned in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0238] It should also be understood that the memory mentioned in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0239] In the embodiments provided in this application, the division of each framework or module is merely a logical function division. In actual implementation, there may be other division methods, for example, multiple frameworks or modules can be combined or integrated into another system, or some features can be ignored or not executed.

[0240] In addition, the functional modules in the various embodiments of the present application may be integrated into a processing module, or each module may exist physically separately, or two or more modules may be integrated into a single module. The above-mentioned integrated modules may be implemented in the form of hardware or software functional modules.

[0241] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0242] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0243] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A communication method, characterized in that: A non-access layer NAS applied to a terminal device, the method comprising: Sending first indication information to the access layer AS of the terminal device, where the first indication information is used to indicate the radio resource control RRC state when the AS sends the serving cell identifier of the terminal device to the NAS; Receiving the serving cell identifier from the AS; Among them, the service cell identifier is used to determine whether the terminal device is located in the network slice service area NS-AoS of the first network slice, and the first network slice belongs to the configured network slice of the terminal device.

2. The method according to claim 1, characterized in that The first indication information also includes a first timer or a first cycle, The first timer is used to instruct the AS to send the serving cell identifier to the NAS after the first timer expires; The first cycle is used to instruct the AS to send the serving cell identifier to the NAS according to the first cycle.

3. The method according to claim 1 or 2, characterized in that: The condition for the NAS to send the first indication information to the AS includes: The NAS supports NS-AoS capability; or, The NAS supports the NS-AoS capability and receives the NS-AoS information of the first network slice of the terminal device in the registration area; or, The NAS supports NS-AoS capability and receives NS-AoS information of the first network slice of the terminal device within the registration area, and the NAS determines that a registration request for the first network slice needs to be initiated / determined that the user plane of the protocol data unit PDU session associated with the first network slice needs to be activated.

4. A communication method, characterized in that: Applied to the access layer AS of the terminal device, the method comprises: Receive first indication information from a non-access layer NAS of the terminal device, and / or receive second indication information from an access network device; wherein the first indication information is used to indicate that the NAS supports the network slice service area NS-AoS capability, and the second indication information is used to instruct the AS to send a serving cell identifier of the terminal device to the NAS; Sending the serving cell identifier to the NAS; Among them, the service cell identifier is used to determine whether the terminal device is located in the NS-AoS of the first network slice, and the first network slice belongs to the configured network slice of the terminal device.

5. The method according to claim 4, characterized in that The first indication information is used to indicate that the NAS supports the NS-AoS capability, including: The first indication information is used to instruct the AS to send a serving cell identifier of the terminal device to the NAS; or, The first indication information includes NS-AoS information of the first network slice.

6. The method according to claim 4 or 5, characterized in that: The first indication information is further used to indicate the RRC state when the AS sends the serving cell identifier to the NAS.

7. The method according to any one of claims 4 to 6, characterized in that: The second indication information is used to instruct the AS to send the serving cell identifier of the terminal device to the NAS, including: The second indication information is used to indicate that the serving cell is configured with 0 resources for a second network slice, and the second network slice is a network slice supported by the tracking area TA where the serving cell is located.

8. The method according to any one of claims 4 to 7, characterized in that: The second indication information is further used to indicate the RRC state when the AS sends the serving cell identifier to the NAS.

9. The method according to any one of claims 4 to 8, characterized in that: The first indication information and / or the second indication information further includes a first timer or a first period, wherein: The first timer is used to instruct the AS to send the serving cell identifier to the NAS after the first timer expires; The first cycle is used to instruct the AS to send the serving cell identifier to the NAS according to the first cycle.

10. The method according to any one of claims 4 to 9, characterized in that: In a case where the first indication information and / or the second indication information indicates an RRC state when the AS sends the serving cell identifier to the NAS, the sending the serving cell identifier to the NAS includes: When the RRC state is met, the serving cell identifier is sent to the NAS.

11. The method according to claim 10, characterized in that The sending the serving cell identifier to the NAS when the RRC state is satisfied includes: If the terminal device does not meet the first condition, then when the RRC state is met, the serving cell identifier is sent to the NAS.

12. The method according to claim 11, characterized in that The first condition includes that the terminal device is in at least one of a capability-limited state, a low power consumption state, and a frequent movement state.

13. A communication method, characterized in that: The method comprises: Sending second indication information to the terminal device, where the second indication information is used to instruct the access layer AS of the terminal device to send a serving cell identifier to the non-access layer NAS of the terminal device; Among them, the service cell identifier is used to determine whether the terminal device is located in the network slice service area NS-AoS of the first network slice, and the first network slice belongs to the configured network slice of the terminal device.

14. The method according to claim 13, characterized in that The second indication information is used to instruct the access layer AS of the terminal device to send a serving cell identifier to the non-access layer NAS of the terminal device, including: The second indication information is used to indicate that the service cell of the terminal device is configured with 0 resources for the second network slice, and the second network slice is a network slice supported by the tracking area where the service cell is located.

15. The method according to claim 13 or 14, characterized in that The second indication information is also used to indicate the radio resource control RRC state when the AS sends the serving cell identifier of the terminal device to the NAS.

16. The method according to any one of claims 13 to 15, characterized in that: The second indication information also includes a first timer or a first cycle, wherein: The first timer is used to instruct the AS to send the serving cell identifier to the NAS after the first timer expires; The first cycle is used to instruct the AS to send the serving cell identifier to the NAS according to the first cycle.

17. The method according to any one of claims 13 to 16, characterized in that: The sending the second indication information to the terminal device includes: If the serving cell does not satisfy the second condition, the second indication information is sent to the terminal device.

18. The method according to claim 17, characterized in that If the serving cell does not meet the second condition, sending the second indication information to the terminal device includes: If the serving cell does not meet the second condition, and the serving cell is configured with 0 resources for the second network slice, sending the second indication information to the terminal device; Among them, the second network slice is a network slice supported by the tracking area TA where the service cell is located.

19. The method according to claim 17 or 18, characterized in that The second condition includes: The service cell supports terminal devices in at least one of a capability-limited state, a low power consumption state, and a frequent movement state.

20. A terminal device, characterized in that: The method comprises a non-access layer NAS and an access layer AS, wherein the NAS is configured to execute the method according to any one of claims 1 to 3, and the AS is configured to execute the method according to any one of claims 4 to 12.

21. An access network device, characterized in that: The access network device is configured to execute the method according to any one of claims 13 to 19.

22. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 19 is implemented.

23. A chip, characterized in that: The method comprises a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the method according to any one of claims 1 to 19 is implemented.

24. A communication device, characterized in that: A non-access layer NAS applied to a terminal device, the device comprising: A sending unit, configured to send first indication information to an access layer AS of the terminal device, wherein the first indication information is used to indicate a radio resource control RRC state when the AS sends a serving cell identifier of the terminal device to the NAS; A receiving unit, configured to receive the serving cell identifier from the AS; Among them, the service cell identifier is used to determine whether the terminal device is located in the network slice service area NS-AoS of the first network slice, and the first network slice belongs to the configured network slice of the terminal device.

25. The device according to claim 24, characterized in that The first indication information also includes a first timer or a first cycle, The first timer is used to instruct the AS to send the serving cell identifier to the NAS after the first timer expires; The first cycle is used to instruct the AS to send the serving cell identifier to the NAS according to the first cycle.

26. The device according to claim 24 or 25, characterized in that The condition for the NAS to send the first indication information to the AS includes: The NAS supports NS-AoS capability; or, The NAS supports the NS-AoS capability and receives the NS-AoS information of the first network slice of the terminal device in the registration area; or, The NAS supports NS-AoS capability and receives NS-AoS information of the first network slice of the terminal device within the registration area, and the NAS determines that a registration request for the first network slice needs to be initiated / determined that the user plane of the protocol data unit PDU session associated with the first network slice needs to be activated.

27. A communication device, characterized in that: Applied to the access layer AS of the terminal device, the device comprises: A receiving unit, configured to receive first indication information from a non-access layer NAS of the terminal device, and / or receive second indication information from an access network device; wherein the first indication information is used to indicate that the NAS supports the network slice service area NS-AoS capability, and the second indication information is used to instruct the AS to send a serving cell identifier of the terminal device to the NAS; A sending unit, configured to send the serving cell identifier to the NAS; Among them, the service cell identifier is used to determine whether the terminal device is located in the NS-AoS of the first network slice, and the first network slice belongs to the configured network slice of the terminal device.

28. The device according to claim 27, characterized in that The first indication information is used to indicate that the NAS supports the NS-AoS capability, including: The first indication information is used to instruct the AS to send a serving cell identifier of the terminal device to the NAS; or, The first indication information includes NS-AoS information of the first network slice.

29. The device according to claim 27 or 28, characterized in that The first indication information is further used to indicate the RRC state when the AS sends the serving cell identifier to the NAS.

30. The device according to any one of claims 27 to 29, characterized in that: The second indication information is used to instruct the AS to send the serving cell identifier of the terminal device to the NAS, including: The second indication information is used to indicate that the serving cell is configured with 0 resources for a second network slice, and the second network slice is a network slice supported by the tracking area TA where the serving cell is located.

31. The device according to any one of claims 27 to 30, characterized in that The second indication information is further used to indicate the RRC state when the AS sends the serving cell identifier to the NAS.

32. The device according to any one of claims 27 to 31, characterized in that The first indication information and / or the second indication information further includes a first timer or a first period, wherein: The first timer is used to instruct the AS to send the serving cell identifier to the NAS after the first timer expires; The first cycle is used to instruct the AS to send the serving cell identifier to the NAS according to the first cycle.

33. The device according to any one of claims 27 to 32, characterized in that In a case where the first indication information and / or the second indication information indicates an RRC state when the AS sends the serving cell identifier to the NAS, the sending unit, configured to send the serving cell identifier to the NAS, includes: The sending unit is configured to send the serving cell identifier to the NAS when the RRC state is met.

34. The device according to claim 33, characterized in that The sending unit, configured to send the serving cell identifier to the NAS when the RRC state is satisfied, includes: The sending unit is used to send the serving cell identifier to the NAS if the terminal device does not meet the first condition and the RRC state is met.

35. The device according to claim 34, characterized in that The first condition includes that the terminal device is in at least one of a capability-limited state, a low power consumption state, and a frequent movement state.

36. A communication device, characterized in that: include: A sending unit, configured to send second indication information to a terminal device, wherein the second indication information is used to instruct an access layer AS of the terminal device to send a serving cell identifier to a non-access layer NAS of the terminal device; Among them, the service cell identifier is used to determine whether the terminal device is located in the network slice service area NS-AoS of the first network slice, and the first network slice belongs to the configured network slice of the terminal device.

37. The device according to claim 36, characterized in that The second indication information is used to instruct the access layer AS of the terminal device to send a serving cell identifier to the non-access layer NAS of the terminal device, including: The second indication information is used to indicate that the service cell of the terminal device is configured with 0 resources for the second network slice, and the second network slice is a network slice supported by the tracking area where the service cell is located.

38. The device according to claim 36 or 37, characterized in that The second indication information is also used to indicate the radio resource control RRC state when the AS sends the serving cell identifier of the terminal device to the NAS.

39. The device according to any one of claims 36 to 38, characterized in that The second indication information also includes a first timer or a first cycle, wherein: The first timer is used to instruct the AS to send the serving cell identifier to the NAS after the first timer expires; The first cycle is used to instruct the AS to send the serving cell identifier to the NAS according to the first cycle.

40. The device according to any one of claims 37 to 39, characterized in that The sending unit is used to send the second indication information to the terminal device, including: The sending unit is used to send the second indication information to the terminal device if the serving cell does not meet the second condition.

41. The device according to claim 40, characterized in that The sending unit, configured to send the second indication information to the terminal device if the serving cell does not meet the second condition, includes: The sending unit is configured to send the second indication information to the terminal device if the serving cell does not meet the second condition and the serving cell is configured with 0 resources for the second network slice; Among them, the second network slice is a network slice supported by the tracking area TA where the service cell is located.

42. The device according to claim 40 or 41, characterized in that The second condition includes: The service cell supports terminal devices in at least one of a capability-limited state, a low power consumption state, and a frequent movement state.

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