CN116420385A

CN116420385A - Cell selection method and device

Info

Publication number: CN116420385A
Application number: CN202080105454.9A
Authority: CN
Inventors: 孙飞; 罗海燕
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-10-15
Filing date: 2020-10-15
Publication date: 2023-07-11
Also published as: WO2022077363A1

Abstract

The embodiment of the application provides a method and a device for selecting a cell, wherein the method comprises the following steps: the terminal equipment determines first network slice information, wherein the first network slice information comprises at least one identifier of a network slice; the terminal equipment receives second network slice information sent by a resident cell, wherein the second network slice information comprises at least one network slice identifier; and the terminal equipment performs cell reselection according to the first network slice information and the second network slice information. By implementing the embodiment of the invention, the efficiency of cell selection can be improved, suitable cells can be selected quickly and effectively, and the time delay and resource expenditure of cell selection are reduced.

Description

Cell selection method and device

Technical Field

The present invention relates to the field of wireless communications, and in particular, to a method and apparatus for cell selection.

Background

With the rapid development of wireless communication technology, the fifth generation (5th Generation,5G) wireless communication technology is a hotspot in the industry. The 5G will support diverse application requirements including access capability supporting higher rate experiences and greater bandwidth, lower latency and highly reliable information interaction, and access and management of larger scale and low cost machine type communication devices, among others. Supporting the ubiquitous demands of various vertical industries and ensuring energy conservation is a key factor in 5G being applied.

For this reason, 5G introduced an important concept of network slicing. One network slice is a combination of network functions and corresponding resource requirements that implement communication traffic and network capabilities, including a Core Network (CN) portion, a radio access network (radio access network, RAN) portion. A network slice forms an end-to-end logical network, thereby meeting the performance requirements of one or more network services of the slice demander. A plurality of network slices are arranged in one CN, so that the requirements of different users and different services are met; one RAN may support multiple network slices. Typically, the network slices supported by cells controlled by one RAN device are a subset of the network slices deployed by the CN, and the network slices supported by cells controlled by different RAN devices may also be different. In other words, different cells have different network slice support capabilities. There may be a case where a terminal device can initiate a service in a first cell but cannot initiate the service in a second cell, because the first cell supports the network slice to which the service belongs, but the second cell does not support the network slice to which the service belongs.

In the prior art, the terminal equipment performs cell selection according to the quality, the priority and the like of the cell link, but the cell selected by the terminal equipment can not support the network slice required by the terminal equipment due to different supporting capability of different cells on the network slice. With consideration of network slicing, there is currently no suitable solution how to effectively select a suitable cell.

Disclosure of Invention

The embodiment of the application provides a cell selection method, which can improve the cell selection efficiency, quickly and effectively select a proper cell and reduce the time delay and resource expense of cell selection.

The present application is described below in terms of various aspects, as will be readily appreciated, the following aspects may be implemented with reference to each other.

In a first aspect, the present application provides a method for cell selection, where the method may be executed by a terminal device, or may be a chip applied in the terminal device. The method comprises the following steps: the terminal equipment determines first network slice information, wherein the first network slice information comprises at least one identifier of a network slice; the terminal equipment receives second network slice information sent by a resident cell, wherein the second network slice information comprises at least one network slice identifier; and the terminal equipment performs cell reselection according to the first network slice information and the second network slice information.

Therefore, the method provided by the embodiment of the application realizes that the terminal equipment in the RRC non-connection state can select to reside in the proper cell supporting the service when the terminal equipment is about to initiate the service, so that the terminal equipment can quickly access the proper cell when the terminal equipment subsequently initiates the service, thereby effectively reducing the time delay of service establishment and signaling overhead.

In one possible implementation, the first network slice information is used to indicate an identity of at least one network slice to which the at least one service to be initiated by the terminal device belongs.

In one possible implementation, the second network slice information includes an identification of at least one network slice supported by the camping cell.

In one possible implementation, the second network slice information includes an identification of at least one network slice supported by the resident cell and an identification of at least one network slice supported by at least one neighbor cell of the resident cell.

In one possible implementation, the cell reselection performed by the terminal device according to the first network slice information and the second network slice information includes: under the condition that the resident cell network slice identifier does not contain the first network slice identifier, the terminal equipment performs cell reselection; wherein the resident cell network slice identity is used to indicate an identity of at least one network slice contained in the second network slice information, and the first network slice identity is used to indicate an identity of at least one network slice contained in the first network slice information.

In one possible implementation, the cell reselection performed by the terminal device according to the first network slice information and the second network slice information includes: the terminal equipment performs cell reselection under the condition that the resident cell network slice identifier does not contain the first network slice identifier and at least one adjacent cell network slice identifier partially or completely contains the first network slice identifier; the resident cell network slice identifier is used for indicating the identifier of at least one network slice supported by the resident cell, the first network slice identifier is used for indicating the identifier of at least one network slice contained in the first network slice information, and the adjacent cell network slice identifier is used for indicating the identifier of at least one network slice supported by one adjacent cell of the resident cell.

In one possible implementation, the cell reselection performed by the terminal device according to the first network slice information and the second network slice information includes: the terminal device performs cell reselection in case the resident cell network slice identification portion comprises a first network slice identification and the number of network slices of the intersection of at least one neighbor cell network slice identification and the first network slice identification is greater than the number of network slices of the intersection of the resident cell network slice identification and the first network slice identification; the resident cell network slice identifier is used for indicating the identifier of at least one network slice supported by the resident cell, the first network slice identifier is used for indicating the identifier of at least one network slice contained in the first network slice information, and the adjacent cell network slice identifier is used for indicating the identifier of at least one network slice supported by at least one adjacent cell of the resident cell.

In one possible implementation, the cell reselection performed by the terminal device according to the first network slice information and the second network slice information includes: the terminal device performs cell reselection when the number of network slices of the intersection of the resident cell network slice identifier and the first network slice identifier is equal to the number of network slices of the intersection of the at least one neighboring cell network slice identifier and the first network slice identifier, and the link quality of the resident cell is lower than the link quality of the at least one neighboring cell; the resident cell network slice identifier is used for indicating the identifier of at least one network slice supported by the resident cell, the first network slice identifier is used for indicating the identifier of at least one network slice contained in the first network slice information, and the adjacent cell network slice identifier is used for indicating the identifier of at least one network slice supported by at least one adjacent cell of the resident cell.

In one possible implementation, the cell reselection performed by the terminal device includes: and the terminal selects the neighbor cell with the largest network slice number of the intersection of the neighbor cell network slice identifier and the first network slice identifier from the at least one neighbor cell to reside.

In one possible implementation, the cell reselection performed by the terminal device includes: under the condition that the number of network slices of the intersection of the network slice identifiers of the plurality of adjacent cells and the first network slice identifier is the largest, the terminal equipment selects the adjacent cell with the highest link quality from the plurality of adjacent cells to reside; or the terminal equipment selects the neighbor cell with the highest priority from the neighbor cells to reside.

In one possible implementation, the cell reselection performed by the terminal device includes: the terminal equipment selects a neighbor cell with the highest link quality from the at least one neighbor cell to reside; or the terminal equipment selects the neighbor cell with the highest priority from the at least one neighbor cell to reside.

In a second aspect, the present application provides a method for PLMN selection, where the method may be performed by a terminal device or may be a chip applied in the terminal device. The method comprises the following steps: the terminal equipment determines third network slice information, wherein the third network slice information comprises at least one identifier of the network slice; and the terminal equipment performs PLMN selection according to the third network slice information.

Therefore, the method provided by the embodiment of the application realizes that the terminal equipment in the RRC non-connection state considers the network slice to which the service possibly initiated subsequently belongs when the PLMN is selected, so that the terminal equipment can select a proper PLMN, and can quickly select the cell for access in the proper PLMN when the terminal equipment initiates the service subsequently, thereby effectively reducing the time delay of service establishment and reducing signaling overhead.

In one possible implementation, the third network slice information is used to indicate an identification of at least one network slice to which the at least one service desired by the terminal device belongs.

In one possible implementation, the terminal device obtains PLMN subscription information, where the PLMN subscription information includes a set of a plurality of subscription PLMN identities of the terminal device and fourth network slice information of each subscription PLMN, where the fourth network slice information is used to indicate an identity of at least one network slice supported by the subscription PLMN.

In one possible implementation, the terminal device obtains network PLMN information comprising an identity of at least one PLMN in the network obtained by the terminal device on at least one RF channel.

In one possible implementation, the terminal device determines a set of potential PLMNs according to the set of subscription PLMN identities and the network PLMN information; the set of potential PLMNs is an intersection of the set of contracted PLMN identities and the network PLMN information.

In one possible implementation, the terminal device determines a set of candidate PLMNs from the set of potential PLMNs according to the third network slice information; the set of candidate PLMNs is an identification of one or more PLMNs in the set of potential PLMNs that support at least one network slice identified by the third network slice information.

In one possible implementation, the terminal device determines that the selected PLMN is the subscribed PLMN having the largest number of network slices of the intersection of the fourth network slice information and the third network slice information in the candidate PLMN set.

In one possible implementation, the terminal device obtains PLMN subscription information, where the PLMN subscription information includes a set of a plurality of subscription PLMN identities of the terminal device, RAT identities of respective subscription PLMNs, and fifth network slice information of respective RATs under respective subscription PLMNs, where the fifth network slice information is used to indicate identities of at least one network slice supported by one RAT under the subscription PLMN.

In one possible implementation, the terminal device determines, from the third network slice information and the fifth network slice information, that the selected PLMN is the contracted PLMN having the largest number of network slices of the intersection of the fifth network slice information and the third network slice information in the candidate PLMN set.

In a third aspect, the present application provides another method for cell selection, where the method may be executed by a terminal device, and may also be a chip applied in the terminal device. The method comprises the following steps: the NAS entity sends a sixth network slice identifier to the AS entity, wherein the sixth network slice identifier comprises an identifier of one network slice; the AS entity listens to the cell broadcast message; and the AS entity performs cell selection according to the sixth network slice identifier.

Therefore, the method provided by the embodiment of the application realizes that the AS entity of the terminal equipment in the RRC non-connection state considers one network slice to which the service possibly initiated subsequently belongs when the cell is selected, so that the AS entity can select a proper cell to reside, the NAS entity can quickly access the proper cell when the service is initiated subsequently, the time delay of service establishment is effectively reduced, and the signaling overhead is reduced.

In one possible implementation, the sixth network slice identifier is used to indicate an identifier of a network slice to which the terminal device subsequently desires to initiate a service.

In one possible implementation, the terminal device may select a cell from a plurality of cells in the selected PLMN for camping according to RSRP, priority or preset criteria of the cell.

In one possible implementation, the terminal device selects a cell for camping from a plurality of cells in one RAT in the selected PLMN according to a priority of the RAT or a preset criterion.

In a fourth aspect, the present application provides another method for cell selection, where the method may be executed by a terminal device, and may also be a chip applied in the terminal device. The method comprises the following steps: the NAS entity sends a seventh network slice identifier to the AS entity, wherein the seventh network slice identifier comprises identifiers of a plurality of network slices; the AS entity listens to the cell broadcast message; and the AS entity performs cell selection according to the sixth network slice identifier.

Therefore, the method provided by the embodiment of the application realizes that the AS entity of the terminal equipment in the RRC non-connection state considers a plurality of network slices to which different services belong when selecting the cells, so that the AS entity can select a proper cell to reside, the NAS entity can quickly access the proper cell when initiating the service subsequently, the time delay of service establishment is effectively reduced, and the signaling overhead is reduced.

In one possible implementation, the seventh network slice identifier is used to indicate an identifier of a plurality of network slices to which the plurality of services that the terminal device is expected to initiate in the following belong.

In one possible implementation, the AS entity may select a cell for camping from a plurality of cells in the selected PLMN according to RSRP, priority or preset criteria of the cell.

In a fifth aspect, the present application provides another method for cell selection, where the method may be executed by a terminal device, and may also be a chip applied in the terminal device. The method comprises the following steps: the NAS entity sends a seventh network slice identifier to the AS entity, wherein the seventh network slice identifier comprises identifiers of a plurality of network slices; the AS entity listens to the cell broadcast message; and the AS entity performs cell selection according to the seventh network slice identifier.

Therefore, the method provided by the embodiment of the application realizes that the AS entity of the terminal equipment in the RRC non-connection state considers the network slice to which one or more services possibly initiated subsequently belong when the cells are selected, so that the AS entity can select a proper cell residence, the NAS entity can quickly access the proper cell when the services are initiated subsequently, the time delay of service establishment is effectively reduced, and the signaling overhead is reduced.

In one possible implementation, the AS entity selects a cell that can support at most a seventh network slice for camping in case the network slice identity supported by each cell obtained by the AS entity from the broadcast message contains the seventh network slice identity to a different extent.

In a sixth aspect, the present application provides a communications apparatus, which may be a terminal device, or an apparatus in a terminal device, or an apparatus that can be used in a matching manner with a terminal device. The communication device may also be a chip system. The communication device is configured to perform the method of the first aspect or any possible implementation of the second aspect or any possible implementation of the third aspect or any possible implementation of the fourth aspect or any possible implementation of the fifth aspect. The functions of the communication device can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more units corresponding to the functions described above. The unit may be software and/or hardware. The operations and advantages performed by the communication device may be referred to the methods and advantages described in the first to fifth aspects, and the repetition is omitted.

In a seventh aspect, the present application provides a communications apparatus comprising a processor, the processor, when invoking a computer program in memory, performing the method of the first aspect or any one of the possible implementations of the second aspect or any one of the possible implementations of the third aspect or any one of the possible implementations of the fourth aspect or any one of the possible implementations of the fifth aspect.

In an eighth aspect, the present application provides a communications apparatus comprising a processor, a memory, and a transceiver for receiving a channel or signal, or transmitting a channel or signal; the memory is used for storing program codes; the processor is configured to invoke the program code from the memory to perform the method of the first aspect or any of the possible implementations of the second aspect or any of the possible implementations of the third aspect or any of the possible implementations of the fourth aspect or any of the possible implementations of the fifth aspect.

In a ninth aspect, the present application provides a communications device comprising a processor and interface circuitry for receiving code instructions and transmitting to the processor; the processor runs the code instructions to perform the method of the first aspect or any one of the possible implementations of the second aspect or any one of the possible implementations of the third aspect or any one of the possible implementations of the fourth aspect or any one of the possible implementations of the fifth aspect.

In a tenth aspect, the present application provides a computer readable storage medium for storing instructions that, when executed, cause the first aspect or any one of the possible implementations of the second aspect or any one of the possible implementations of the third aspect or any one of the possible implementations of the fourth aspect or any one of the possible implementations of the fifth aspect to be implemented.

In an eleventh aspect, the present application provides a computer program product comprising instructions which, when executed, cause the method of the first aspect or any one of the possible implementations of the second aspect or any one of the possible implementations of the third aspect or any one of the possible implementations of the fourth aspect or any one of the possible implementations of the fifth aspect to be implemented.

In a twelfth aspect, the present application provides a chip comprising logic circuitry for communicating with a module external to the chip, and an input-output interface for running a computer program or instructions to implement the method of the first aspect or any one of the possible implementations of the second aspect or any one of the possible implementations of the third aspect or any one of the possible implementations of the fourth aspect or any one of the possible implementations of the fifth aspect.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

Drawings

The drawings that accompany the present application can be briefly described as follows:

fig. 1 is a schematic diagram of a communication system according to an embodiment of the present application;

fig. 2 is a schematic diagram of a protocol stack of a terminal device according to an embodiment of the present application;

fig. 3 is a schematic flow chart of a method for cell reselection according to an embodiment of the present application;

fig. 4 is a flowchart of a method for PLMN selection according to an embodiment of the present application;

fig. 5 is a schematic flow chart of a method for selecting a cell according to an embodiment of the present application;

fig. 6 is a flowchart of another method for cell selection according to an embodiment of the present application;

fig. 7 is a flowchart of a method for further cell selection according to an embodiment of the present application;

fig. 8 is a flowchart of another method for cell selection according to an embodiment of the present application;

fig. 9 is a flowchart of another method for cell reselection according to an embodiment of the present application;

fig. 10 is a flowchart of a method for cell reselection provided in an embodiment of the present application;

fig. 11 is a flowchart of another method for cell reselection according to an embodiment of the present application;

Fig. 12 is a schematic block diagram of a terminal device provided in an embodiment of the present application;

fig. 13 is another schematic block diagram of a terminal device provided in an embodiment of the present application;

fig. 14 is a schematic block diagram of a chip according to an embodiment of the present application.

Detailed Description

Embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

In this application, the term "exemplary" is used to mean "serving as an example, instance, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. The following description is presented to enable any person skilled in the art to make and use the invention. In the following description, details are set forth for purposes of explanation. It will be apparent to one of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well-known structures and processes have not been described in detail so as not to obscure the description of the invention with unnecessary detail. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

The terms "first," "second," "third," "fourth" and the like in the description and in the claims of this application and in the above-described figures, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the present application described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The terms "system" and "network" are often used interchangeably herein.

The technical scheme of the invention is described in detail below by specific examples. The following embodiments may be combined with each other, and some embodiments may not be repeated for the same or similar concepts or processes.

The technical solution of the embodiment of the present application may be applied to various wireless communication systems, for example: a long term evolution (Long Term Evolution, LTE) system, a fifth generation (5th generation,5G) mobile communication system, a New Radio (NR) communication system, a Next Generation (NG) communication system, a future mobile communication system, and the like.

In a wireless communication system, one terminal device is connected to a RAN device through a wireless link, and communication with other terminal devices or access to the wireless internet or the like is achieved via a CN device to which the RAN device is connected. Typically, one terminal device is wirelessly connected to one RAN device to enable communication. Fig. 1 shows a schematic diagram of a wireless communication system 100 according to an embodiment of the present application. Wherein the terminal device 120 establishes a wireless connection with the RAN device 140 through an air interface and accesses the core network 160. In a practical system, in order to meet the coverage of a wireless network, a plurality of RAN apparatuses are typically deployed in one area, and cells controlled by different RAN apparatuses need to provide seamless coverage as much as possible. As shown in fig. 1, RAN device 140 is surrounded by RAN device 142, RAN device 144, and RAN device 146. Different RAN devices may have interfaces that communicate with each other, such as an X2 interface or an Xn interface. In one possible scenario, the RAN devices operate on the same frequency band and are deployed in different geographic locations, with each controlled cell collectively providing seamless coverage, such as with a degree of overlapping coverage between the cell controlled by RAN device 140 and the cell controlled by RAN device 142. The overlapping coverage area can typically be neither too large nor too small, and the determination of the size of the overlapping coverage area requires consideration of the trade-off between interference between co-frequency cells and inter-cell handover performance. In another possible scenario, some RAN devices operate on different frequency bands to form heterogeneous network coverage, e.g., cells controlled by RAN device 140 operate on a lower frequency band and have a larger coverage area, cells controlled by RAN device 142 operate on a higher frequency band and have a smaller coverage area, these RAN devices may be deployed in the same or different geographic locations, the respective controlled cells may have a completely overlapping coverage area, e.g., RAN device 140 operates on a lower frequency band, RAN device 142 operates on a higher frequency band, and the coverage area of the cell controlled by RAN device 140 can completely or mostly cover the coverage area of the cell controlled by RAN device 142.

In a practical system, the RAN device shown in fig. 1 may be a next generation base station, a next generation Node B (next-generation Node B, gNB), a next generation evolved Node B (next-generation evolved Node B, ng-eNB), or the like, or may be an Access Point (AP) in a wireless local area network (Wireless Local Area Networks, WLAN), or an evolved Node B (eNB, eNodeB) in LTE, or a relay station, or an access point, or an in-vehicle device, a wearable device, a transmission and reception point (transmission and reception point, TRP), or the like. It should be appreciated that the terminal device communicates with the RAN device via transmission resources (e.g., frequency domain resources, time domain resources, code domain resources, etc.) used by one or more cells managed by the RAN device, which may belong to a macro cell (macro cell), a super cell (super cell), or a small cell (small cell), where the small cell may include: urban cells (metro cells), micro cells (micro cells), pico cells (pico cells), femto cells (femto cells) and the like, and the small cells have the characteristics of small coverage area and low transmitting power and are suitable for providing high-rate data transmission services. The terminal device in fig. 1 may also be referred to as a User Equipment (UE), an access terminal, a subscriber unit, a subscriber station, a mobile station, a remote terminal, a mobile device, a user terminal, a wireless communication device, a user agent, or a user equipment. The terminal device may be a Station (ST) in a WLAN, may be a cellular telephone, a cordless telephone, a SIP telephone, a wireless local loop (wireless local loop, WLL) station, a personal digital assistant (personal digital assistant, PDA) device, a handheld device with wireless communication functionality, a relay device, a computing device or other processing device coupled to a wireless modem, an in-vehicle device, a wearable device, and a next generation communication system, e.g. a terminal device in a 5G network or a terminal device in a future evolved public land mobile network (public land mobile network, PLMN) network, etc. By way of example, and not limitation, in embodiments of the present application, the terminal device may also be a wearable device. The wearable device can also be called as a wearable intelligent device, and is a generic name for intelligently designing daily wear by applying wearable technology and developing wearable devices, such as glasses, gloves, watches, clothes, shoes and the like. The wearable device is a portable device that is worn directly on the body or integrated into the clothing or accessories of the user. The wearable device is not only a hardware device, but also can realize a powerful function through software support, data interaction and cloud interaction. The generalized wearable intelligent device includes full functionality, large size, and may not rely on the smart phone to implement complete or partial functionality, such as: smart watches or smart glasses, etc., and focus on only certain types of application functions, and need to be used in combination with other devices, such as smart phones, for example, various smart bracelets, smart jewelry, etc. for physical sign monitoring.

To facilitate understanding, concepts involved in the embodiments of the present application are first described. It should be understood that the following conceptual explanations may be limited by the specific case of the embodiments of the present application, but do not represent that the application is limited to this specific case, and that the following conceptual explanations may also differ with the specific case of different embodiments:

1) RRC state: the RRC states generally include three, namely an RRC CONNECTED (rrc_connected) state, an RRC IDLE (rrc_idle) state, and an RRC INACTIVE (rrc_inactive) state. Wherein the RRC idle state and the RRC inactive state may be collectively referred to as an RRC non-connected state. When the terminal equipment is in an RRC connection state, the terminal equipment, the RAN and the CN are all established with communication connection, and when data arrives at the CN, the data can be sent to the terminal equipment through the RAN, or the data of the terminal equipment can be sent to the RAN; when the terminal equipment is in an RRC idle state, the terminal equipment is in communication connection with the RAN and the CN, and when data needs to be transmitted, a communication link between the terminal equipment and the RAN and the CN needs to be established; when the terminal device is in the RRC inactive state, the communication connection between the terminal device and the RAN and the communication connection between the terminal device and the CN are established before the terminal device are indicated, but the communication link between the terminal device and the RAN are released, the RAN stores the context of the terminal device, and when data needs to be transmitted, the RAN can quickly recover the communication link.

2) Non-access stratum (NAS) and Access Stratum (AS): the protocol stack of the terminal device can be divided into a NAS layer and an AS layer according to the difference of the destination end in communication connection with the terminal device. The NAS layer protocol realizes the communication connection between the terminal equipment and the CN side, and the AS layer protocol realizes the communication connection between the terminal equipment and the RAN side. Fig. 2 shows a protocol stack structure of one possible terminal device. Wherein the AS layer comprises a plurality of protocol layers, such AS a radio resource control (radio resource control, RRC) layer, a service data adaptation protocol (service data adaptation protocol, SDAP) layer, a packet data convergence layer protocol (packet data convergence protocol, PDCP) layer, a radio link control (radio link control, RLC) layer, a medium access control (media access control, MAC) layer, and a Physical (PHY) layer; correspondingly, there is also a peer-to-peer protocol layer on the RAN side to enable a communication connection with the terminal device. The NAS layer realizes the communication connection between the terminal equipment and the CN side, and the CN side also has a peer NAS layer. It should be appreciated that the terminal device is not in direct communication with the CN side, and that NAS messages for the terminal device to communicate with the CN are typically encapsulated in AS messages for the terminal device to communicate with the RAN.

3) Network slice identification: in a network, a network slice needs to have corresponding identification information to identify. Currently 3gpp SA2 defines single network slice selection assistance information (single network slice selection assistance information, S-network slice SAI) to identify one network slice. Each S-network slice SAI is composed of a slice/service type (SST) for distinguishing services and a slice distinction (slice differentiator, SD) for distinguishing tenants. One or more S-network slices SI constitute a network slice SAI. Wherein the network slice identity of each network slice may be characterized using at least one of the following parameters:

1. network slice type information, for example, the network slice type information may indicate network slice types such as enhanced Mobile BroadBand service (eMBB), ultra-reliable low latency communication (Ultra-Reliable Low Latency Communications, URLLC), mass machine type communication (massive Machine Type Communication, mctc), or alternatively, the network slice type information may also indicate end-to-end network slice types, including RAN-to-CN network slice types, also referred to as RAN-side network slice types, or CN-side network slice types;

2. The service type information is related to a specific service, for example, the service type information can indicate service characteristics such as video service, internet of vehicles service, voice service and the like or information of the specific service;

3. tenant (Tenant) information indicating customer information, such as Tencent, national grid, etc., that created or rented the network slice;

4. user group information indicating grouping information for grouping users according to a certain characteristic, such as a user level, etc.;

5. slice group information for indicating that according to a certain feature, for example, all network slices that the terminal device can access may be taken as one slice group, or groups of network slices may be divided according to other criteria;

6. network slice instance information for indicating an instance identifier created for the network slice and feature information, for example, an identifier may be allocated to the network slice instance for indicating the network slice instance, a new identifier may be mapped on the basis of the network slice instance identifier, the network slice instance is associated, and the receiver may identify a specific network slice instance indicated by the identifier according to the identifier;

7. a private core network (Dedicated Core Network, DCN) identifier, which is used to uniquely indicate a private core network in an LTE system or an eLTE system, such as a core network that is private to the internet of things, optionally, the DCN identifier may be mapped with a network slice identifier, a network slice identifier may be mapped by the DCN identifier, and a DCN identifier may also be mapped by the network slice identifier.

When the terminal device is switched on, the terminal device performs public land mobile network (public land mobile network, PLMN) selection to select a network serving the terminal device. The NAS entity of the terminal device may notify the AS entity of the selected PLMN for cell selection and cell reselection (reselection) by the AS entity. In addition, the terminal device may also periodically search for PLMNs with higher priority. Alternatively, after the terminal device leaves the coverage of the previously registered PLMN, a new PLMN may be automatically selected, or an indication may be received from the available PLMNs to effect manual selection of PLMNs. Cell selection refers to the terminal device selecting a suitable cell in the selected PLMN to provide available services after completing PLMN selection, and monitoring the control channel of the cell. This process is also referred to as terminal equipment camping on a cell. Camping on a cell allows the terminal device to receive system information of the camping cell, access a control channel of the camping cell to establish or restore an RRC connection, receive a network paging message from the control channel of the camping cell, etc. Cell reselection refers to that after the terminal equipment resides in one cell, a more suitable cell is found according to the cell reselection criteria, and the terminal equipment reselects the more suitable cell and resides in the cell.

In NR, different PLMNs may support different network slices, and different cells may also support different network slices. The inventor finds that in the prior art, when the terminal device performs cell selection (reselection), the network slice supporting condition of the selected cell is not considered, and there is a possibility that the cell selected by the terminal device does not support the network slice required by the terminal device, thereby causing incorrect cell selection and wasting network resources. Further, when the terminal device performs PLMN selection, whether the selected PLMN supports a network slice subscribed by the terminal device or a desired network slice is not considered, which also causes incorrect PLMNU selection and wastes network resources. For this reason, the embodiment of the application provides a technical solution for cell selection, where the terminal device performs cell selection (reselection) based on the required network slice. Further, the embodiment of the application also provides a technical scheme that the terminal equipment performs PLMN selection based on the signed network slice or the expected network slice.

The following embodiments are specifically provided herein, and the technical solutions of the present application are described in detail with reference to fig. 3 to 11 by using specific method embodiments. The following embodiments may be combined with each other, and some embodiments may not be repeated for the same or similar concepts or processes. It should be noted that fig. 3 to 11 are schematic flowcharts of the method embodiments of the present application, and show detailed communication steps or operations of the method, but these steps or operations are only examples, and other operations or variations of the various operations in fig. 3 to 11 may also be performed by the embodiments of the present application. Further, the respective steps in fig. 3 to 11 may be performed in a different order from that presented in fig. 3 to 11, respectively, and it is possible that not all the operations in fig. 3 to 11 are to be performed.

Fig. 3 is a schematic flow chart of a method for cell selection according to an embodiment of the present application. The method 300 is applied to a scenario in which a terminal device residing in one cell selects a new cell to reside when it is about to initiate a service. In this scenario, the resident cell does not support the network slice to which the service to be initiated by the terminal device belongs, and the terminal device needs to select to reside in a new cell to support the network slice to which the service to be initiated by the terminal device belongs; or the resident cell supports a part of network slices to which the service to be initiated by the terminal equipment belongs, and the terminal equipment needs to select to reside in a new cell to support the network slices to which the service to be initiated by the terminal equipment belongs more or completely. This new cell selection is also referred to as cell reselection, i.e. the terminal device reselects from a camping cell to a new cell for camping. The flow described in fig. 3 includes the following steps:

s301, the terminal equipment determines target network slice information.

The terminal device may camp on a cell when in the RRC non-connected state, the cell on which the terminal device camps being referred to as a camping cell. When the terminal equipment is about to initiate a service, the terminal equipment acquires network slice information corresponding to the service (called a target service), and the network slice is called a target network slice. It should be appreciated that the impending initiation of a service by the terminal device may also be referred to as the state of the terminal device going from the RRC non-connected state to the RRC connected state as a result of the service. Typically, the terminal device needs to establish a PDU session with the network to carry the target service, and thus the target network slice is also the network slice associated with the PDU session to which the target service belongs. It should be appreciated that the terminal device may initiate multiple services simultaneously, i.e. the target service contains multiple services, and these services may belong to one PDU session or may belong to multiple PDU sessions. When the services belong to a PDU session, the target network slice corresponds to a network slice associated with the PDU session; when the traffic respectively belongs to a plurality of PDU sessions, the target network slice corresponds to one or more network slices associated with the plurality of PDU sessions. In other words, the target service may be one or more services, and the target network slice may be one or more network slices, and the number of services included in the target service and the number of network slices included in the target network slice are not specifically limited in this application.

Specifically, the terminal device determines the target network slice information by the following manner: firstly, a NAS entity of terminal equipment determines a target service and a target network slice; second, the NAS entity of the terminal device sends the network slice identifier of the target network slice (referred to AS the target network slice identifier) to the AS entity of the terminal device. Thus, the AS entity of the terminal device obtains the target network slice identifier. Optionally, the NAS entity sends the Access Category (AC) and the Access Identity (AI) corresponding to the target service to the AS entity together with the target network slice identifier. It should be appreciated that when the target service contains multiple services, each of the services may have the same or different ACs and AI; the target network slice identification may comprise network slice identifications of one or more network slices.

S302, the resident cell sends network slice information to the terminal equipment. Accordingly, the terminal device receives network slice information from the camping cell.

In this step, the resident cell transmits network slice information to the terminal device resident in the cell by means of cell broadcast.

In one possible implementation, the network slice information is used to indicate network slice information of network slices supported by the camping cell. Illustratively, the network slice information includes network slice identifications of one or more network slices supported by the camping cell.

In another possible implementation, the network slice information is used to indicate network slice information of network slices supported by the camping cell and network slice information of network slices supported by the neighboring cell. Illustratively, the network slice information includes network slice identifications of one or more network slices supported by the camping cell and network slice identifications of one or more network slices supported by the neighboring cell. It should be understood that a neighbor cell corresponds to one or more cells adjacent to the camping cell.

S303, the terminal equipment determines to perform cell reselection.

In this step, the terminal device determines to perform cell reselection based on the information of the target network slice and the information of the network slices of the resident cell and the neighbor cell acquired in the above step S302.

Illustratively, the terminal device determines to perform cell reselection based on the target network slice identification and the identification of the network slice obtained in step S302. Wherein the network slice identity of one or more network slices supported by the camped cell is referred to as a camped cell network slice identity. Accordingly, any one cell in the adjacent cells is defined as a first adjacent cell, and the identification of the network slice supported by the first adjacent cell is called as a first adjacent cell network slice identification. It should be appreciated that the resident cell network slice identity and the first neighbor cell network slice identity may each comprise one or more network slice identities. Corresponding to the two possible implementations of step S302 described above, there are two ways in this step:

Cell reselection mode one:

this approach corresponds to the case where the network slice information sent by the resident cell contains only the resident cell network slice identity.

And when the resident cell network slice identifier does not contain the target network slice identifier, the terminal equipment determines to perform cell reselection. In this case, since the camping cell does not support the target network slice, the terminal device needs to reselect a cell that can support the target network slice for camping.

Cell reselection mode two:

this approach corresponds to the case where the network slice information sent by the camping cell contains a camping cell network slice identity and one or more first neighbor cell network slice identities.

In one possible implementation, the terminal device determines to perform cell reselection when the resident cell network slice identity does not contain the target network slice identity, and there are one or more first neighbor cell network slice identities that contain the target network slice identity. In this case, since the camping cell does not support the target network slice, the terminal device needs to reselect a cell that can support the target network slice for camping.

In another possible implementation, the terminal device determines to perform cell reselection when the resident cell network slice identity does not contain the target network slice identity, and there are one or more first neighbor cell network slice identities containing part of the target network slice identity. In this case, since the camping cell does not support the target network slice, the terminal device needs to reselect a cell supporting as many target network slices as possible for camping. For example, the target network slice is identified as network slice #1, network slice #2, and network slice #3, and the network slices of neighbor #1 are identified as network slice #1, network slice #4, and network slice #5, the network slices of neighbor #3 are identified as network slice #2, network slice #3, and network slice #5, and the network slices of neighbor #5 are identified as network slice #3 and network slice #4, the terminal device may reselect neighbor #3 for residence because neighbor #3 can support the most network slices in the target network slice.

In yet another possible implementation, the terminal device determines to perform cell reselection when the resident cell network slice identity comprises part of the target network slice identity and the presence of one or more first neighbor cell network slice identities also comprises part of the target network slice identity. When the network slice identifiers of the first neighboring cell exist and more network slice identifiers than the network slice identifiers of the resident cell contain more network slice identifiers in the target network slice identifiers, the terminal equipment can reselect a cell supporting as many target network slices as possible to be resident. For example, when there is a first neighbor network slice identifier and the camping cell network slice identifier contains the same number of network slice identifiers in the target network slice identifiers, and the first neighbor has better link quality, the terminal device may reselect a first neighbor that can support the same number of target network slices and has better link quality to camp on. Illustratively, the link quality of a cell may be measured by the terminal receiving the value of the RSRP of the cell, when the larger the RSRP value, the higher the link quality of the cell is indicated; conversely, when the RSRP value is smaller, it indicates that the link quality of the cell is lower.

In yet another possible implementation, while the resident cell network slice identifier includes the target network slice identifier, the first neighbor cell network slice identifier also includes the target network slice identifier, and when the first neighbor cell has a better link quality, the terminal device may reselect to a first neighbor cell that can support the target network slice and has a better link quality for the resident cell.

S304, the terminal equipment performs cell reselection and camps on the target cell.

For the first cell reselection mode, the terminal device searches for the neighbor cell of the resident cell and selects a cell for residence. The terminal device reads network slice identifiers of one or more first neighboring cells of the neighboring cells respectively, and if the network slice identifiers of the first neighboring cells completely or maximally contain the target network slice identifier, the first neighboring cells are called candidate cells. When only one candidate cell exists, the terminal equipment resides in the candidate cell; when a plurality of candidate cells exist, the terminal equipment selects one or a plurality of candidate cells, and selects one cell from the candidate cells to reside. The terminal device may select one of the candidate cells for camping on according to link quality, priority, or other preset criteria. The cell in which the terminal device selects to camp is called a target cell. It should be noted that, for such a cell reselection mode, the terminal device may select the target cell for camping in various manners in the prior art. The present application is not particularly limited thereto.

For the second cell reselection mode, if the first neighboring cell network slice identifier completely or maximally includes the target network slice identifier, the first neighboring cell is referred to as a candidate cell. When only one candidate cell exists, the terminal equipment resides in the candidate cell; when a plurality of candidate cells exist, the terminal equipment selects one or a plurality of candidate cells, and selects one cell from the candidate cells to reside. The terminal device may select one of the candidate cells for camping on according to link quality, priority, or other preset criteria. The cell in which the terminal device selects to camp is called a target cell.

After the terminal equipment completes cell reselection and selects to reside in the target cell, the terminal equipment realizes the synchronization with the downlink signal of the target cell and listens to the control channel of the target cell, thereby residing in the target cell.

In step S302, the camping cell broadcasts the network slice information to the terminal device in the RRC non-connected state. In an actual system, if the resident cell is a serving cell CONNECTED in an rrc_connected state before the terminal device enters the RRC non-CONNECTED state, the serving cell may also send the network slice information to the terminal device in a unicast manner (e.g. through RRC signaling) before the terminal device enters the RRC non-CONNECTED state from the rrc_connected state. In this way, when the terminal device enters the RRC non-connected state and the cell in which it resides is the serving cell, the terminal device may directly determine whether to perform cell reselection according to the network slice information that it previously acquired from the serving cell.

Through the steps in the embodiment, when the terminal equipment in the RRC non-connection state is about to initiate the service, the terminal equipment can select to reside in a proper cell supporting the service, so that the terminal equipment can quickly access the proper cell when the terminal equipment subsequently initiates the service, the time delay of service establishment is effectively reduced, and the signaling overhead is reduced.

Fig. 4 is a flowchart of a method for PLMN selection according to an embodiment of the present application. The method 400 is applied to a scenario in which the terminal device performs PLMN initial selection at power-on or periodically performs PLMN selection after registering the network. In this scenario, the terminal device has subscribed to multiple PLMNs, and different PLMNs may support different network slices. When the terminal device performs PLMN initial selection or period selection, the terminal device does not have service communication with the network, but the terminal device has a desired network slice, i.e. the terminal device may initiate a service belonging to the desired network slice in the following. Thus, the terminal device needs to select a PLMN that can support the desired network slice. The flow described in fig. 4 includes the following steps:

s401, the terminal equipment acquires network slice information supported by the contracted PLMN.

Optionally, if the terminal device has the capability of supporting multiple RAT systems, the terminal device further obtains network slice information supported by each RAT system. In this case, the network slice information supported by the subscribed PLMN acquired by the terminal device further includes network slice information supported by each RAT system supported by the terminal device, where the network slice information supported by the subscribed PLMN may also be referred to as network slice information supported by multiple RATs under the subscribed PLMN.

The terminal device signs up with a plurality of PLMNs. There are many implementations for the terminal device to obtain the network slice information supported by the subscribed PLMN. In one possible implementation, the network slice information supported by the multiple PLMNs subscribed to by the terminal device is pre-configured, e.g., present in a SIM card inserted into the terminal device or pre-stored on the terminal device. Similarly, the network slice information supported by different RAT systems of the terminal device may also be preconfigured in the above manner. In another possible implementation, the network slice information supported by the PLMNs subscribed by the terminal device is stored on the terminal device based on a network-to-terminal device communication interface, and the network may update the network slice information stored on the terminal device through the communication interface. For example, a network management system of an operator stores and updates network slice information supported by PLMNs of the operator in a terminal device through a communication interface with the terminal device. Similarly, the network slice information supported by different RAT systems of the terminal device may also be saved and updated in the above manner.

The terminal device may further obtain the network slice identifier of the one or more network slices supported by each of the different RAT systems (also referred to as the network slice identifier supported by multiple RATs under the subscribed PLMN). It should be appreciated that the network slice identity supported by the subscribed PLMN and the network slice identity supported by the multi-RAT under the subscribed PLMN may each comprise one or more network slice identities.

Illustratively, table 1 gives an illustration of network slice identities supported by a subscribed PLMN of a terminal device.

TABLE 1

PLMN list
>PLMN identification
>Network slice identification list

Wherein, the PLMN list comprises a plurality of PLMN identifications; each PLMN identity corresponds to a network slice identity list comprising network slice identities of one or more network slices, the network slice identity list representing network slices supported by the PLMN.

Illustratively, table 2 presents an illustration of network slice identities supported by multiple RATs under a subscribed PLMN of a terminal device.

TABLE 2

PLMN list
>PLMN identification
>RAT list
>>RAT identification
>>Network slice identification list

Wherein, the PLMN list comprises a plurality of PLMN identifications; each PLMN identifier corresponds to a RAT list; each RAT list contains one or more RAT identities, each RAT identity corresponds to a network slice identity list containing network slice identities of one or more network slices, and the network slice identity list represents network slices supported by the RAT. It should be appreciated that the RAT identification may be a name of the RAT, an index, or other forms of characters or strings that can be used to identify one RAT, etc., as not specifically limited herein.

S402, the terminal equipment determines a desired network slice.

Specifically, the NAS entity of the terminal device determines the desired network slice. Wherein the desired network slice is used to indicate the network slice to which the service that the terminal device may initiate in the following belongs. It should be appreciated that it is contemplated that a network slice may comprise one or more network slices. When one or more services possibly initiated by the terminal equipment subsequently belong to a PDU session, the expected network slice is one network slice associated with the PDU session; when a plurality of services that the terminal device may subsequently initiate belong to a plurality of PDU sessions, respectively, the network slice is expected to be one or more network slices associated with the plurality of PDU sessions.

S403, the terminal equipment performs PLMN selection based on the expected network slice.

Based on the different RAT formats supported by the terminal device, there may be multiple implementations of the terminal device for PLMN selection based on the desired network slice. In one possible implementation, the terminal device supports only one RAT format, for example. In this case, the terminal device scans a Radio Frequency (RF) channel corresponding to the RAT system to find available PLMNs. At each frequency point (carrier), the terminal device searches for the cell with the strongest signal and reads the system information of the cell to find which PLMN or PLMNs the cell belongs to. If the terminal equipment reads one or more PLMN identifications from the cell with the strongest signal, the AS entity reports each read PLMN identification to the NAS entity. Illustratively, when the terminal device measures that the RSRP value of the cell with the strongest signal is greater than or equal to-110 dBm, the AS layer of the terminal device reports one or more PLMN identifications to which the read cell belongs to the NAS layer; and under the condition that the terminal equipment measures that the RSRP value of the cell with the strongest signal is smaller than-110 dBm, the AS entity of the terminal equipment reports the read one or more PLMN identifications of the cell and the corresponding RSRP value to the NAS entity.

After acquiring a plurality of PLMN identifications (called PLMN identification set) reported by an AS, a NAS entity of the terminal equipment performs PLMN selection according to the expected network slice. Specifically, the terminal device performs PLMN selection in combination with the PLMN identifier set acquired by the NAS entity, the network slice identifier supported by the subscribed PLMN acquired in step S401, and the desired network slice.

Illustratively, table 3 shows network slice identities supported by PLMNs subscribed to by the terminal device.

TABLE 3 Table 3

PLMN list
>PLMN#1
>NS#1,NS#2,NS#3
>PLMN#2
>NS#3,NS#5
>PLMN#3
>NS#2,NS#7,NS#8

In this example, the terminal device has subscribed to plmn#1, plmn#2 and plmn#3. Wherein, PLMN#1 subscribed by the terminal equipment supports NS#1, NS#2 and NS#3; PLMN#2 subscribed by the terminal equipment supports NS#3 and NS#5; plmn#3 subscribed to by the terminal equipment supports ns#2, ns#7, and ns#8.

Illustratively, assume that the desired NS determined by the terminal device in step S402 above is ns#3, and that the plurality of PLMN identities acquired by the terminal device scanning the RF channel are plmn#1, plmn#3, plmn#4, and plmn#5. The terminal device may determine the potential PLMN set as { plmn#1, plmn#3}, in this step, in combination with table 3 and the PLMN identities obtained by scanning the RF channels. In this example, the potential PLMN set is an intersection of a PLMN set subscribed to by the terminal device and a PLMN set acquired by the terminal device scanning the RF channel. Further, since the desired network slice is ns#3, and both plmn#1 and plmn#2 in table 3 support ns#3, but plmn#2 does not belong to the potential PLMN set, the PLMN selected by the terminal device is plmn#1.

Illustratively, assume that the desired network slice determined by the terminal device in step S402 above is ns#2, and that the plurality of PLMN identities acquired by the terminal device scanning the RF channels are plmn#1, plmn#3, plmn#4, and plmn#5. The terminal device may determine the potential PLMN set as { plmn#1, plmn#3}, in this step, in combination with table 3 and the PLMN identities obtained by scanning the RF channels. Likewise, in this example, the potential PLMN set is an intersection of the PLMN set subscribed to by the terminal device and the PLMN set acquired by the terminal device scanning the RF channel. Further, since the desired network slice is ns#2 and both plmn#1 and plmn#3 in table 3 support ns#2, the terminal equipment needs to select one of plmn#1 and plmn#3. Wherein the PLMN set { plmn#1, plmn#3} is also referred to as a candidate PLMN set. In this example, the candidate PLMN set is a subset or full set of the potential PLMN set that contains one or more PLMN identities in the potential PLMN set that support the desired network slice. And the terminal equipment performs PLMN selection in the candidate PLMN set. For example, if the terminal device reads plmn#1 and plmn#3 from different cells, the terminal device may select a PLMN according to the RSRP value of each cell, e.g., the RSRP value of the cell read to plmn#1 is smaller than the RSRP value of the cell read to plmn#3, and the PLMN selected by the terminal device is plmn#3; if the terminal device reads plmn#1 and plmn#3 in the same cell, the terminal device may select PLMN according to a preset criterion (such as operator priority), for example, the priority of plmn#1 is higher than that of plmn#3, and the PLMN selected by the terminal device is plmn#1.

When the desired network slice is a plurality of network slices, the terminal device selects a PLMN that can fully support or maximally support the desired network slice. If there are a plurality of PLMNs satisfying the above conditions, the terminal device may select one PLMN according to the RSRP value read to the cell of the corresponding PLMN; or select a PLMN based on a preset criteria such as operator priority.

In another possible implementation, the terminal device supports multiple RAT formats. In this case, the terminal device may sequentially scan RF channels corresponding to each RAT system from top to bottom according to the RAT priority to find available multiple PLMNs; or, the terminal device may sequentially scan RF channels corresponding to each RAT system in order to find available PLMNs; or, the terminal device may scan RF channels corresponding to each RAT system in turn according to a preset rule to find available multiple PLMNs. In the embodiment of the application, the terminal equipment can consider which RAT system or systems supported by the terminal equipment support the expected network slice before performing RF channel scanning, so that the time for RF channel scanning is saved, resources are saved, and the efficiency is improved; the terminal device may also perform RF channel scanning on all RAT systems supported by the terminal device in a conventional manner, and then consider the desired network slice, so that the terminal device has better backward compatibility.

And the terminal equipment performs PLMN selection by combining the PLMN identification set acquired by the NAS entity, the network slice identification supported by the multi-RAT under the contracted PLMN acquired in the step S401 and the expected network slice. The specific implementation can be realized in the following two ways:

PLMN selection mode one:

the terminal equipment firstly screens a candidate RAT set from network slice identifiers supported by multiple RATs under PLMNs subscribed by the terminal equipment according to the expected network slice, then performs RF channel scanning for various RAT modes in the candidate RAT set to find a potential PLMN set, then the terminal equipment finds the candidate PLMN set from the potential PLMN set according to the supporting capacity of the expected network slice indicated by the supported RAT, and then selects one PLMN from the candidate PLMN set.

Illustratively, table 4 shows network slice identities supported by multiple RATs under a PLMN subscribed by the terminal device.

TABLE 4 Table 4

PLMN list
>PLMN#1
>>RAT#1
>>NS#1,NS#2,NS#3
>>RAT#2
>>NS#2,NS#3
>PLMN#2
>>RAT#2
>>NS#1,NS#2,NS#3
>>RAT#3
>>NS#1,NS#3,NS#4
>>RAT#5
>>NS#4,NS#5
>PLMN#3
>>RAT#4
>>NS#1,NS#2,NS#3
>>RAT#6
>>NS#3,NS#4

Table 4 shows that the terminal device has subscribed to plmn#1, plmn#2 and plmn#3 and supports six RAT systems, rat#1, rat#2, rat#3, rat#4, rat#5 and rat#6. Wherein, PLMN#1 subscribed by the terminal equipment supports RAT#1 and RAT#2; RAT #1 supports NS #1, NS #2, and NS #3, and RAT #2 supports NS #2 and NS #3. PLMN#2 subscribed by the terminal equipment supports RAT#2, RAT#3 and RAT#5; wherein RAT#2 supports NS#1, NS#2, and NS#3, RAT#3 supports NS#1, NS#3, and NS#4, and RAT#5 supports NS#4, and NS#5. PLMN#3 subscribed by the terminal equipment supports RAT#4 and RAT#6; where RAT#4 supports NS#1, NS#2, and NS#3, and RAT#6 supports NS#3 and NS#4.

For example, assuming that the desired network slice determined in the above step S402 is ns#4, the terminal device selects a RAT system capable of supporting ns#4 from six RAT systems supported by the terminal device, and obtains rat#3, rat#5, and rat#6. The terminal device may then scan for multiple PLMN identities acquired by RF channels of RAT #3, RAT #5, and RAT #6, respectively. Assuming that the PLMN identities acquired by the terminal device by scanning on the RF channel of RAT #3 are PLMN #1, PLMN #2 and PLMN #3, the PLMN identities acquired by scanning on the RF channel of RAT #5 are PLMN #2, PLMN #4 and PLMN #5, and the PLMN identities acquired by scanning on the RF channel of RAT #6 are PLMN #1, PLMN #2 and PLMN #4, a potential PLMN set { PLMN #1, PLMN #2, PLMN #3, PLMN #4, PLMN #5}. And then, the terminal equipment further selects a candidate PLMN set from the potential PLMN sets according to the supporting capability of the supported RAT system to the desired network slice. For example, for plmn#1, rat#1 and rat#2 are contained, but ns#4 is not supported, so plmn#1 does not belong to the candidate PLMN set; for PLMN #2, RAT #3 and RAT #5 supporting NS #4 are included, so PLMN #2 belongs to the candidate PLMN set; for PLMN#3, containing RAT#6 supporting NS#4, PLMN#3 belongs to the candidate PLMN set; for PLMN #4 and PLMN #5, since the PLMNs subscribed to by the terminal device do not contain PLMN #4 and PLMN #5, neither PLMN #4 nor PLMN #5 belongs to the candidate PLMN set. Thus, the candidate PLMN set is { plmn#2, plmn#3}. Further, if the terminal device reads plmn#2 and plmn#3 from different cells, the terminal device may select a PLMN according to the RSRP value of each cell, for example, the RSRP value of the cell read to plmn#2 is smaller than the RSRP value of the cell read to plmn#3, and the PLMN selected by the terminal device is plmn#3; if the terminal device reads plmn#2 and plmn#3 in the same cell, the terminal device may select PLMN according to a preset criterion (such as operator priority), for example, the priority of plmn#2 is higher than that of plmn#3, and the PLMN selected by the terminal device is plmn#1. It should be understood that, in this example, the terminal device may also scan the RF channels of RAT #3, RAT #5 and RAT #6 in a specific order according to the RAT priority or a preset criterion, or scan only the RF channels of a partial RAT system, which is not specifically limited in this application.

By the PLMN selection method, the terminal equipment considers which RAT system or RAT systems supported by the terminal equipment support the expected network slice, and then performs RF channel scanning, so that the time for RF channel scanning is saved, resources are saved, and the efficiency is improved.

PLMN selection mode II:

the terminal equipment firstly scans RF channels of various RAT systems supported by the terminal equipment according to a traditional mode, finds a potential PLMN set, and then carries out PLMN selection according to a desired network slice.

Illustratively, table 4 is still employed as the network slice identity for multi-RAT support under the PLMN subscribed by the terminal device and it is assumed that the desired network slice determined by the terminal device in step S402 above is still ns#4. First, the terminal device scans the RF channels of the RAT systems (rat#1, rat#2, rat#3, rat#4, rat#5, and rat#6) supported by the terminal device to obtain a plurality of PLMN identities, and a potential PLMN set { plmn#1, plmn#2, plmn#3, plmn#4, plmn#5}. And then, the terminal equipment further selects a candidate PLMN set from the potential PLMN sets according to the supporting capability of the supported RAT system to the desired network slice. For example, for PLMN #1, PLMN #1 does not belong to the candidate PLMN set because neither RAT #1 nor RAT #2 it contains supports NS # 4; for plmn#2, plmn#2 belongs to the candidate PLMN set because both rat#3 and rat#5 it contains support ns#4; for PLMN #3, PLMN #3 belongs to the candidate PLMN set because it contains RAT #6 supporting NS # 4; for PLMN #4 and PLMN #5, since the PLMNs subscribed to by the terminal device do not contain PLMN #4 and PLMN #5, neither PLMN #4 nor PLMN #5 belongs to the candidate PLMN set. Thus, the candidate PLMN set is { plmn#2, plmn#3}. Further, if the terminal device reads plmn#2 and plmn#3 from different cells, the terminal device may select a PLMN according to the RSRP value of each cell, for example, the RSRP value of the cell read to plmn#2 is smaller than the RSRP value of the cell read to plmn#3, and the PLMN selected by the terminal device is plmn#3; if the terminal device reads plmn#2 and plmn#3 in the same cell, the terminal device may select PLMN according to a preset criterion (such as operator priority), for example, the priority of plmn#2 is higher than that of plmn#3, and the PLMN selected by the terminal device is plmn#1. It should be understood that, in this example, the terminal device may also scan the RF channels of RAT #3, RAT #5 and RAT #6 in a specific order according to the RAT priority or a preset criterion, or scan only the RF channels of a partial RAT system, which is not specifically limited in this application.

According to the method, PLMN selection is performed, the terminal equipment firstly scans the RF channels of all RAT systems supported by the terminal equipment according to the traditional method to obtain a potential PLMN set, and then PLMN selection is performed according to the expected network slice, so that better backward compatibility is achieved.

In the above two modes, when the desired network slice is a plurality of network slices, the terminal device selects a PLMN that can fully support or maximally support the desired network slice. If there are a plurality of PLMNs satisfying the above conditions, the terminal device may select one PLMN according to the RSRP value read to the cell of the corresponding PLMN; or select a PLMN based on a preset criteria such as operator priority.

Through the steps in the embodiment, the network slice to which the service possibly initiated by the following is considered when the terminal equipment in the RRC non-connected state selects the PLMN is realized, so that the terminal equipment can select a proper PLMN, and the terminal equipment can quickly select the cell for access in the proper PLMN when the terminal equipment initiates the service subsequently, thereby effectively reducing the time delay of service establishment and reducing signaling overhead.

After the terminal equipment finishes selecting the PLMN, the terminal equipment executes cell selection to select one cell under the PLMN for residence. After finishing PLMN selection, the terminal device performs cell selection and resides in the selected cell. Alternatively, the terminal device periodically searches for a higher priority PLMN and, after selecting a new PLMN, searches for a suitable cell for camping.

Fig. 5 is a flowchart of another method for cell selection according to an embodiment of the present application. The method 500 is applied to a scenario in which, after the terminal device completes selecting a PLMN, the terminal device performs cell selection to select a cell under the PLMN for camping. The flow described in fig. 5 includes the following steps:

s501, the terminal equipment determines a desired network slice.

S502, the terminal equipment performs cell selection according to the expected network slice.

The terminal device completes PLMN selection after the previous fig. 4 embodiment. In this step, the terminal device selects one of the cells in the selected PLMN for camping according to the desired network slice among the one or more cells.

In one possible implementation, when the PLMN selected by the terminal device comprises a plurality of cells, and each cell supports a desired network slice, the terminal device may select one cell for camping from among the cells according to the RSRP, priority or preset criteria. When the terminal device supports multiple RAT systems, the terminal device may also select a suitable cell in one RAT from the priority or the preset grant side of the RAT to camp on.

In another possible implementation, when the PLMN selected by the terminal device includes a plurality of cells and each cell has a different network slice supporting capability, the terminal device selects one cell capable of supporting the desired network slice from the plurality of cells to camp on according to the desired network slice. If there are a plurality of such cells, the terminal device may further select one cell from among the cells for camping according to the cell RSRP, priority or preset criteria. When the terminal device supports multiple RAT systems, the terminal device may also select a suitable cell in one RAT from the priority or the preset grant side of the RAT to camp on.

Through the steps in the embodiment, the network slice to which the service possibly initiated subsequently belongs is considered when the terminal equipment in the RRC non-connected state selects the cell, so that the terminal equipment can select a proper cell to reside, the terminal equipment can quickly access the proper cell when the terminal equipment initiates the service subsequently, the time delay of service establishment is effectively reduced, and the signaling overhead is reduced.

Corresponding to the flow of the cell selection method shown in fig. 5, fig. 6 to 8 respectively provide different ways how the NAS entity and the AS entity inside the terminal device interact to implement cell selection.

Fig. 6 provides a flow chart of yet another cell selection method. The method 600 is applied to a NAS entity of a terminal device to determine a scenario in which a desired network slice is one network slice. The flow described in fig. 6 includes the following steps:

s601, the NAS entity sends a network slice identifier of a desired network slice to the AS entity. Accordingly, the AS entity receives a network slice identification of a desired one of the network slices from the NAS entity.

In this step, the NAS entity sends its determined identity of the desired network slice to the AS entity. Wherein the desired network slice is a network slice, and the desired network slice identity corresponds to a network slice identity.

S602, the AS entity listens to the cell broadcast message.

After completing PLMN selection, in this step the terminal device listens to broadcast messages of each of one or more cells in its selected PLMN. Wherein the broadcast message contains information of the network slice supported by the cell that sent the broadcast message, e.g., network slice identity of one or more network slices supported by the cell.

S603, the AS entity selects a cell according to the expected network slice identifier.

In this step, the AS entity performs cell selection according to the network slice identity of the desired network slice acquired in the above step S601 and the network slice identities supported by the one or more cells acquired in the above step S602.

In one possible implementation, the AS entity obtains that only the network slice identifier supported by one cell contains the desired network slice identifier in step S602, and then the AS entity selects the cell to camp on.

In another possible implementation, the AS entity obtains that the network slice identifiers supported by the cells in step S602 above include the desired network slice identifier, and then the AS entity may select a cell from the cells to camp on according to the RSRP, the priority or a preset criterion of the cell.

Through the steps in the embodiment, the AS entity of the terminal equipment in the RRC non-connection state considers one network slice to which the service possibly initiated subsequently belongs when the cell is selected, so that the AS entity can select a proper cell to reside, the NAS entity can quickly access the proper cell when the service is initiated subsequently, the time delay of service establishment is effectively reduced, and the signaling overhead is reduced.

Fig. 7 provides a flow chart of yet another cell selection method. The method 700 is applied to a scenario in which a NAS entity of a terminal device selects a camping cell for a plurality of network slices. The flow described in fig. 7 includes the following steps:

s701, the NAS entity sends network slice identifiers of the plurality of first network slices to the AS entity. Accordingly, the AS entity receives network slice identifications of a plurality of first network slices from the NAS entity.

In this step, the NAS entity sends a plurality of first network slice identities to the AS entity. The plurality of first network slice identities are determined by the NAS entity, wherein the first network slice identity is an identity of one network slice for which the terminal device is subscribed to the selected PLMN. The NAS entity may send the identity of some or all network slices subscribed by the terminal device with the selected PLMN to the AS layer. Optionally, the plurality of first network slices are desired network slices having a plurality of network slices determined by the NAS entity.

S702, the AS entity listens to the cell broadcast message.

S703, the AS entity selects a cell according to the plurality of first network slice identifiers.

In this step, the AS entity performs cell selection according to the network slice identifiers of the plurality of first network slices acquired in the above step S701 and the network slice identifiers supported by the one or more cells acquired in the above step S702.

In a possible implementation, the AS entity includes the plurality of first network slice identifiers to different extents, where the network slice identifiers supported by each cell acquired in the step S702 include the plurality of first network slice identifiers, and then the AS entity selects one of the cells to camp on. For example, some cells do not support first network slices, some cells support part of first network slices, and some cells support all first network slices. The AS entity selects a cell capable of supporting the most first network slices to reside; or the AS entity selects a specific cell for camping according to a preset criterion, for example, the specific cell is not the first network slice capable of supporting the most, but the RSRP value of the specific cell is the largest.

In another possible implementation, the AS entity includes the plurality of first network slice identifiers to the same extent AS the network slice identifiers supported by the cells acquired in the step S702, and then the AS entity may select one cell from the plurality of cells to camp on according to the RSRP, the priority or a preset criterion of the cell.

Through the steps in the embodiment, the AS entity of the terminal equipment in the RRC non-connection state considers a plurality of network slices to which different services belong when selecting the cells, so that the AS entity can select a proper cell to reside, the NAS entity can quickly access the proper cell when initiating the service subsequently, the time delay of service establishment is effectively reduced, and the signaling overhead is reduced.

Fig. 8 provides a flow chart of yet another cell selection method. The NAS entity of the method 800 applied to the terminal device provides a plurality of network slices, and the AS entity determines a scenario of a desired network slice. The flow described in fig. 8 includes the following steps:

s801, the NAS entity sends network slice identifiers of a plurality of first network slices to the AS entity. Accordingly, the AS entity receives network slice identifications of a plurality of first network slices from the NAS entity.

S802, the AS entity determines the desired network slice.

In this step, the AS entity determines a desired network slice from the plurality of first network slices acquired in step S801 described above. The desired network slice is used to indicate the network slice to which the traffic that the terminal device may subsequently initiate belongs. It should be appreciated that it is contemplated that a network slice may comprise one or more network slices. When one or more services possibly initiated by the terminal equipment subsequently belong to a PDU session, the expected network slice is one network slice associated with the PDU session; when a plurality of services that the terminal device may subsequently initiate belong to a plurality of PDU sessions, respectively, the network slice is expected to be one or more network slices associated with the plurality of PDU sessions.

S803, the AS entity listens to the cell broadcast message.

S804, the AS entity selects a cell according to the expected network slice identifier.

In this step, the AS entity performs cell selection according to the network slice identity of the desired network slice determined in the above step S802 and the network slice identities supported by the one or more cells acquired in the above step S803.

In one possible implementation, when the desired network slice identifier comprises a network slice identifier, the AS entity determines in step S803 that the network slice identifier supported by only one cell comprises the desired network slice identifier, and the AS entity selects the cell to camp on.

In another possible implementation, when the desired network slice identifier includes a network slice identifier, the AS entity obtains that the network slice identifiers supported by the plurality of cells include the desired network slice identifier in step S803, and then the AS entity may select a cell from the plurality of cells to camp on according to the cell RSRP, the priority, or a preset criterion.

In yet another possible implementation, when the desired network slice identifier includes a plurality of network slice identifiers, the AS entity includes the desired network slice identifier to a different extent from the network slice identifiers supported by the respective cells acquired in step S803, and then the AS entity selects one of the cells to camp on. For example, some cells do not support desired network slices, some cells support some desired network slices, and some cells support all desired network slices. The AS entity selects a cell which can support the most expected network slices to reside; or the AS entity selects a specific cell for camping according to a preset criterion, for example, the specific cell is not capable of supporting the most desired network slices, but the RSRP value of the specific cell is the largest.

In yet another possible implementation, when the desired network slice identifier includes a plurality of network slice identifiers, the AS entity includes the desired network slice identifier to the same extent AS the network slice identifiers supported by the respective cells acquired in step S803 above, the AS entity may select one cell from the plurality of cells to camp on according to the cell RSRP, priority, or a preset criterion.

Through the steps in the embodiment, the AS entity of the terminal equipment in the RRC non-connection state considers the network slice to which one or more services possibly initiated later belong when the cells are selected, so that the AS entity can select a proper cell to reside, the NAS entity can quickly access the proper cell when the services are initiated later, the time delay of service establishment is effectively reduced, and the signaling overhead is reduced.

PLMN and cell selection is completed at the terminal device, and resides in one cell. Thereafter, the terminal device may also reselect a new cell for camping on based on the desired network slice for cell reselection. The difference from the scenario of cell reselection described in the embodiment of fig. 3 is that the terminal device is not about to initiate a service at this time, i.e. the terminal device is not to switch from the RRC non-connected state to the RRC connected state, the terminal device will still remain in the RRC non-connected state, but the terminal device may subsequently initiate a service belonging to the desired network slice.

Fig. 9 provides a flow chart of yet another cell selection method. The method 900 is applied to a scenario in which a NAS entity of a terminal device determines that a desired network slice is a network slice, and reselects a new cell to camp on. In this scenario, the camping cell does not support the desired network slice for the terminal device, which needs to camp on a new cell to support the desired network slice. The flow described in fig. 9 includes the following steps:

s901, a NAS entity of the terminal equipment sends a network slice identifier of a desired network slice to an AS entity. Accordingly, the AS entity receives a network slice identification of a desired one of the network slices from the NAS entity.

S902, the resident cell sends AS information to the terminal equipment. Accordingly, the terminal device receives network slice information from the camping cell.

Specifically, the AS entity of the terminal device receives network slice information from the camping cell.

In this step, the resident cell transmits network slice information to the terminal device resident in the cell by means of cell broadcast. In one possible implementation, the network slice information is used to indicate network slice information of network slices supported by the camping cell. Illustratively, the network slice information includes network slice identifications of one or more network slices supported by the camping cell.

S903, the terminal equipment determines to perform cell reselection.

Specifically, the AS entity of the terminal device determines to perform cell reselection according to the desired network slice identifier.

S904, the terminal equipment performs cell reselection and camps on the target cell.

Specifically, the AS entity of the terminal device performs cell reselection according to the desired network slice identifier and camps on the target cell.

Steps S903 and S904 are similar to steps S303 and S304 in the foregoing embodiment, and are not described herein.

In step S902, the camping cell broadcasts network slice information to the terminal device in the RRC non-connected state. In an actual system, if the resident cell is a serving cell connected in an RRC connection state before the terminal device enters the RRC non-connection state, the serving cell may also send the network slice information to the terminal device in a unicast manner (e.g. through RRC signaling) before the terminal device enters the RRC non-connection state from the RRC connection state. In this way, when the terminal device enters the RRC non-connected state and the cell in which it resides is the serving cell, the terminal device may directly determine whether to perform cell reselection according to the network slice information that it previously acquired from the serving cell.

Through the steps in this embodiment, the terminal device realizes that the AS entity can select to reside in a suitable cell supporting a network slice under the condition that the terminal device in the RRC non-connected state may subsequently initiate a service belonging to the network slice, so that the terminal device can quickly access the suitable cell when subsequently initiating the service, thereby effectively reducing the time delay of service establishment and reducing signaling overhead.

Fig. 10 provides a flow chart of yet another cell selection method. The NAS entity of the method 1000 applied to the terminal device reselects a new cell for a plurality of network slices to camp on. In this scenario, the resident cell does not support the plurality of network slices of the terminal device, which needs to reside in a new cell to support the plurality of network slices; or the camping cell portion supports the plurality of network slices for the terminal device, which the terminal device needs to camp on a new cell to support more or all of the plurality of network slices. The flow depicted in diagram 1000 includes the steps of:

s1001, a NAS entity of the terminal equipment sends network slice identifiers of a plurality of first network slices to an AS entity. Accordingly, the AS entity receives network slice identifications of a plurality of first network slices from the NAS entity.

The step S1001 is similar to the step S701 in the previous embodiment, and will not be described herein.

S1002, the resident cell sends AS information to the terminal equipment. Accordingly, the terminal device receives network slice information from the camping cell.

S1003, the terminal equipment determines to perform cell reselection.

Specifically, the AS entity of the terminal equipment determines to perform cell reselection according to the plurality of first network slice identifiers.

S1004, the terminal equipment performs cell reselection and camps on the target cell.

Specifically, the AS entity of the terminal equipment performs cell reselection according to the plurality of first network slice identifiers and resides in the target cell.

Steps S1002 to S1004 are similar to steps S902 to S904, respectively, in the foregoing embodiments, and are not repeated herein.

In step S1002, the camping cell broadcasts the network slice information to the terminal device in the RRC non-connected state. In an actual system, if the resident cell is a serving cell CONNECTED in an rrc_connected state before the terminal device enters the RRC non-CONNECTED state, the serving cell may also send the network slice information to the terminal device in a unicast manner (e.g. through RRC signaling) before the terminal device enters the RRC non-CONNECTED state from the rrc_connected state. In this way, when the terminal device enters the RRC non-connected state and the cell in which the terminal device resides is the serving cell, the terminal device may directly determine whether to perform cell reselection according to the network slice information that it previously acquired from the serving cell.

By the steps of the embodiment, when the terminal equipment supporting a plurality of network slices is in an RRC non-connection state or the terminal equipment in the RRC non-connection state possibly initiates the service belonging to the plurality of network slices, the AS entity can select to reside in a proper cell supporting the plurality of network slices, so that the terminal equipment can quickly access the proper cell when the terminal equipment initiates the service, thereby effectively reducing the time delay of service establishment and signaling overhead.

Fig. 11 provides a flow chart of yet another cell selection method. The NAS entity of the method 1100 applied to the terminal device provides a plurality of network slices, and the AS entity determines a scenario of a desired network slice. In this scenario, the camping cell does not support the desired network slice of the terminal device, which needs to camp on a new cell to support the desired network slice; or the camping cell supports a part of the desired network slice for the terminal device, the terminal device needs to camp on a new cell to support the desired network slice more or completely. The flow shown in fig. 11 includes the following steps:

s1101, the NAS entity of the terminal equipment sends network slice identifiers of a plurality of first network slices to the AS entity. Accordingly, the AS entity receives network slice identifications of a plurality of first network slices from the NAS entity.

S1102, an AS entity of the terminal equipment determines a desired network slice.

Steps S1101 and S1102 are similar to steps S801 and S802, respectively, in the foregoing embodiment, and are not repeated herein.

And S1103, the resident cell sends AS information to the terminal equipment. Accordingly, the terminal device receives network slice information from the camping cell.

The step S1103 is similar to the step S902 of the previous embodiment, and will not be repeated herein.

S1104, the terminal equipment determines to perform cell reselection.

Specifically, the AS entity of the terminal device determines to perform cell reselection.

S1105, the terminal equipment performs cell reselection and camps on the target cell.

Specifically, the AS entity of the terminal device performs cell reselection and camps on the target cell.

Steps S1104 and S1105 are similar to steps S303 and S304, respectively, in the foregoing embodiment, and are not repeated herein.

In step S1103, the camping cell broadcasts the network slice information to the terminal device in the RRC non-connected state. In an actual system, if the resident cell is a serving cell CONNECTED in an rrc_connected state before the terminal device enters the RRC non-CONNECTED state, the serving cell may also send the network slice information to the terminal device in a unicast manner (e.g. through RRC signaling) before the terminal device enters the RRC non-CONNECTED state from the rrc_connected state. In this way, when the terminal device enters the RRC non-connected state and the cell in which it resides is the serving cell, the terminal device may directly determine whether to perform cell reselection according to the network slice information that it previously acquired from the serving cell.

By the steps of the embodiment, when the terminal equipment supporting a plurality of network slices is in an RRC non-connection state and the terminal equipment is likely to initiate the service belonging to one network slice subsequently, the AS entity can select to reside in a proper cell supporting the network slice, so that the terminal equipment can quickly access the proper cell when the terminal equipment subsequently initiates the service, thereby effectively reducing the time delay of service establishment and reducing signaling overhead.

It should be noted that, in the embodiments shown in fig. 9 to 11, although the terminal device is in the RRC non-connected state, the core network side may store the context information of the PDU session performed by the terminal device before entering the RRC non-connected state.

In the case where the core network side holds the context information of one PDU session of the terminal device, in the embodiments shown in fig. 9 to 11, correspondingly, the NAS entity sends the network slice associated with the PDU session AS the desired network slice to the AS, or the AS entity holds the network slice associated with the PDU session and determines AS the desired network slice. The AS entity performs cell reselection based on the desired network slice.

In the case where the core network side stores the context information of multiple PDU sessions of the terminal device, in the embodiments shown in fig. 9 to 11, accordingly, in one possible implementation, the NAS entity stores the network slices associated with the multiple PDU sessions, determines one network slice from the multiple network slices associated with the multiple PDU sessions AS a desired network slice, and sends the desired network slice identifier to the AS entity, where the AS entity performs cell reselection according to the desired network slice identifier. In another possible implementation, the NAS entity stores network slices associated with the plurality of PDU sessions, the NAS entity sends network slice identifiers of the plurality of network slices associated with the plurality of PDU sessions to the AS entity, and the AS entity determines one network slice identifier from the network slice identifiers AS a desired network slice identifier, and performs cell reselection according to the desired network slice identifier. In yet another possible implementation, the NAS entity stores network slices associated with the plurality of PDU sessions, the NAS entity sends network slice identities of the plurality of network slices associated with the plurality of PDU sessions to the AS entity, and the AS entity determines from the cell broadcast message to reselect to a cell that can support the plurality of network slices to a maximum extent. In yet another possible implementation, the AS entity stores network slices associated with the plurality of PDU sessions, the AS entity determines one network slice from the plurality of network slices associated with the plurality of PDU sessions AS a desired network slice, and the AS entity performs cell reselection according to the desired network slice identifier. In yet another possible implementation, the AS entity maintains network slices associated with the plurality of PDU sessions, and the AS entity determines from the cell broadcast message that the reselection resides to a cell that can maximally support the plurality of network slices.

It should be noted that, the terminal device in the RRC non-connected state may move, resulting in the terminal device moving from one registration area to another registration area. In this case, the terminal device needs to initiate a procedure of registration area update to acquire a new registered network slice. The new registered network slice serves as a candidate network slice at the time of the above-mentioned cell reselection, i.e. the target network slice or the desired network slice considered by the terminal device at the time of initiating the cell reselection is one or more of the candidate network slices.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, produces a flow or function in accordance with embodiments of the present application, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in or transmitted from one computer-readable storage medium to another, for example, by wired (e.g., coaxial cable, optical fiber, digital Subscriber Line (DSL)), or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid State Disk (SSD)), etc. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present patent application.

Method embodiments of the present application are described above in detail in connection with fig. 3-11, and apparatus embodiments of the present application are described below in connection with fig. 12-14. It should be understood that apparatus embodiments and method embodiments correspond with each other and that similar descriptions may refer to the method embodiments. It is noted that the device embodiments may be used in conjunction with the methods described above, or may be used alone.

Fig. 12 shows a schematic block diagram of a terminal device 1200 according to an embodiment of the present application, where the terminal device 1200 may correspond (e.g. may be configured or itself be) to a terminal device described in the above method 300, or a terminal device described in the above method 400, or a terminal device described in the above method 500, or a terminal device described in the above method 600, or a terminal device described in the above method 700, or a terminal device described in the above method 800, or a terminal device described in the above method 900, or a terminal device described in the above method 1000, or a terminal device described in the above method 1100, or a terminal device described in other embodiments.

The terminal device 1200 may include a communication unit 1201 and a processing unit 1202. The communication unit 1201 may include a transmission unit for implementing a transmission function and/or a reception unit for implementing a reception function, and the communication unit 1201 may implement the transmission function and/or the reception function. The communication unit may also be described as a transceiver unit. The terminal apparatus 1200 may further include a storage unit 1203 for storing a program or data to be executed by the processing unit 1202 or storing information received and/or transmitted through the communication unit 1201. The terminal device 1200 may be a terminal device, a device in another device, or a device that can be used in cooperation with a terminal device.

The units in the terminal device 1200 are configured to perform the actions or processes performed by the terminal device described in the method 300, the terminal device described in the method 400, the terminal device described in the method 500, the terminal device described in the method 600, the terminal device described in the method 700, the terminal device described in the method 800, the terminal device described in the method 900, the terminal device described in the method 1000, the terminal device described in the method 1100, or the terminal device described in other embodiments, respectively. Here, in order to avoid redundancy, detailed description thereof is omitted.

Fig. 13 shows a schematic block diagram of a terminal device 1300 according to an embodiment of the present application, where the terminal device 1300 may correspond (e.g. may be configured or itself be) to a terminal device described in the above method 300, or a terminal device described in the above method 400, or a terminal device described in the above method 500, or a terminal device described in the above method 600, or a terminal device described in the above method 700, or a terminal device described in the above method 800, or a terminal device described in the above method 900, or a terminal device described in the above method 1000, or a terminal device described in the above method 1100, or a terminal device described in other embodiments.

The terminal device 1300 may include one or more processors 1301. Processor 1301 may be a general purpose processor or a special purpose processor, etc. For example, a baseband processor or a central processing unit. The baseband processor may be used for processing communication protocols and communication data, and the central processor may be used for controlling the terminal device, executing the computer program, and processing data of the computer program.

Terminal device 1300 may also include a transceiver 1302, an antenna 1303. The transceiver 1302 may be referred to as a transceiver unit, a transceiver circuit, etc. for implementing a transceiver function. The transceiver 1302 may include a receiver, which may be referred to as a receiver or a receiving circuit, etc., for implementing a receiving function; the transmitter may be referred to as a transmitter or a transmitting circuit, etc., for implementing a transmitting function.

Optionally, the terminal device 1300 may include one or more memories 1304, on which a computer program 1305 may be stored, which may be executed on the terminal device 1300, so that the terminal device 1300 performs the method described in the above method embodiments. Optionally, the memory 1304 may also have data stored therein. The terminal apparatus 1300 and the memory 1304 may be provided separately or may be integrated.

In one possible implementation, a transceiver for implementing the receive and transmit functions may be included in processor 1301. For example, the transceiver may be a transceiver circuit, or an interface circuit. The transceiver circuitry, interface or interface circuitry for implementing the receive and transmit functions may be separate or may be integrated. The transceiver circuit, interface or interface circuit may be used for reading and writing codes/data, or the transceiver circuit, interface or interface circuit may be used for transmitting or transferring signals.

In a possible implementation, the processor 1301 may store a computer program 1306, where the computer program 1306 runs on the processor 1301, and may cause the terminal device 1300 to perform the method described in the above method embodiment. The computer program 1306 may be solidified in the processor 1301, in which case the processor 1301 may be implemented in hardware.

In one possible implementation, terminal device 1300 may include circuitry that may implement the functions of transmitting or receiving or communicating in the foregoing method embodiments. The processors and transceivers described herein may be implemented on integrated circuits (integrated circuit, ICs), analog ICs, radio frequency integrated circuits RFICs, mixed signal ICs, application specific integrated circuits (application specific integrated circuit, ASIC), printed circuit boards (printed circuit board, PCB), electronic devices, and the like. The processor and transceiver may also be fabricated using a variety of IC process technologies such as complementary metal oxide semiconductor (complementary metal oxide semiconductor, CMOS), N-type metal oxide semiconductor (NMOS), P-type metal oxide semiconductor (positive channel metal oxide semiconductor, PMOS), bipolar junction transistor (bipolar junction transistor, BJT), bipolar CMOS (BiCMOS), silicon germanium (SiGe), gallium arsenide (GaAs), etc.

It is to be appreciated that the processor 1301 may be a central processing unit (central processing unit, CPU), a network processor (network processor, NP), a hardware chip, or any combination thereof. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (programmable logic device, PLD), or a combination thereof. The PLD may be a complex programmable logic device (complex programmable logic device, CPLD), a field-programmable gate array (field-programmable gate array, FPGA), general-purpose array logic (generic array logic, GAL), or any combination thereof. The memory 1304 may be a volatile memory (RAM), such as a random-access memory (RAM); non-volatile memory (non-volatile memory) such as read-only memory (ROM), flash memory (flash memory), hard disk (HDD) or Solid State Drive (SSD); combinations of the above types of memories are also possible.

The processor 1301 and the transceiver 1302 of the terminal device 1300 are configured to perform the actions or processes performed by the terminal device described in the method 300, the terminal device described in the method 400, the terminal device described in the method 500, the terminal device described in the method 600, the terminal device described in the method 700, the terminal device described in the method 800, the terminal device described in the method 900, the terminal device described in the method 1000, the terminal device described in the method 1100, or the terminal device described in other embodiments, respectively. Here, in order to avoid redundancy, detailed description thereof is omitted.

The structure of the terminal apparatus 1300 may not be limited to that of fig. 13. Terminal device 1300 may be a stand-alone device or may be part of a larger device. For example, the terminal device 1300 may be:

(1) A stand-alone integrated circuit IC, or chip, or a system-on-a-chip or subsystem;

(2) A set of one or more ICs, optionally including storage means for storing data, a computer program;

(3) An ASIC, such as a Modem (Modem);

(4) Modules that may be embedded within other devices;

(5) Receivers, terminals, smart terminals, cellular telephones, wireless devices, handsets, mobile units, vehicle devices, network devices, cloud devices, artificial intelligence devices, etc.;

(6) Others, and so on.

For the case where the terminal device 1300 may be a chip or a chip system, reference may be made to the schematic structural diagram of the chip 1400 shown in fig. 14. The chip 1400 shown in fig. 14 comprises a logic circuit 1401 and an input-output interface 1402, the input-output interface 1402 being for communication with a module outside said chip 1400, the logic circuit 1401 being for running a computer program or instructions to implement the functions of any of the method embodiments described above. The number of input/output interfaces 1402 may be plural.

Optionally, the chip 1400 further comprises a memory 1403, the memory 1403 being used for storing necessary computer programs (or instructions) and data.

The logic 1401 and the input-output interface 1402 in the chip 1400 are configured to perform the actions or processes performed by the terminal device described in the method 300, the terminal device described in the method 400, the terminal device described in the method 500, the terminal device described in the method 600, the terminal device described in the method 700, the terminal device described in the method 800, the terminal device described in the method 900, the terminal device described in the method 1000, the terminal device described in the method 1100, or the terminal device described in other embodiments, respectively. Here, in order to avoid redundancy, detailed description thereof is omitted.

In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of elements is merely a logical functional division, and there may be additional divisions of actual implementation, e.g., multiple elements or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling shown or discussed as being coupled or directly coupled or communicatively coupled to each other may be via some interface, device or unit whether indirectly coupled or communicatively coupled, whether electrically, mechanically or otherwise.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer-readable storage medium. Based on such understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of the embodiments of the present application. And the aforementioned storage medium comprises: a U-disk, a removable hard disk, a read-only memory (ROM), a random access memory (random access memory, RAM), a magnetic disk, or an optical disk, or other various media capable of storing program codes.

The foregoing is merely specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope disclosed in the present application, and all changes and substitutions are included in the protection scope of the present application. Therefore, the protection scope of the patent application is subject to the protection scope of the claims.

Claims

A method of cell selection, comprising:

the terminal equipment determines first network slice information, wherein the first network slice information comprises at least one identifier of a network slice;

the terminal equipment receives second network slice information sent by a resident cell, wherein the second network slice information comprises at least one network slice identifier; and

and the terminal equipment performs cell reselection according to the first network slice information and the second network slice information.
The method according to claim 1, wherein the first network slice information is used for indicating an identity of at least one network slice to which at least one service to be initiated by the terminal device belongs.
The method of claim 1, wherein the second network slice information comprises an identification of at least one network slice supported by the camped cell.
The method of claim 1, wherein the second network slice information comprises an identification of at least one network slice supported by the camped cell and an identification of at least one network slice supported by at least one neighbor cell of the camped cell.
A method according to any of claims 1 to 3, wherein the terminal device performs cell reselection based on the first and second network slice information, comprising:

under the condition that the resident cell network slice identifier does not contain the first network slice identifier, the terminal equipment performs cell reselection; wherein the resident cell network slice identifier is used for indicating an identifier of at least one network slice contained in the second network slice information, and the first network slice identifier is used for indicating an identifier of at least one network slice contained in the first network slice information.
The method according to claim 1, 2 or 4, wherein the terminal device performs cell reselection according to the first network slice information and the second network slice information, comprising:

the terminal equipment performs cell reselection under the condition that the resident cell network slice identifier does not contain a first network slice identifier and at least one adjacent cell network slice identifier partially or completely contains the first network slice identifier; the resident cell network slice identifier is used for indicating the identifier of at least one network slice supported by the resident cell, the first network slice identifier is used for indicating the identifier of at least one network slice contained in the first network slice information, and the adjacent cell network slice identifier is used for indicating the identifier of at least one network slice supported by one adjacent cell of the resident cell.
The method according to claim 1, 2 or 4, wherein the terminal device performs cell reselection according to the first network slice information and the second network slice information, comprising:

the terminal device performs cell reselection in case the resident cell network slice identification portion comprises a first network slice identification and the number of network slices of the intersection of at least one neighbor cell network slice identification and the first network slice identification is greater than the number of network slices of the intersection of the resident cell network slice identification and the first network slice identification; the resident cell network slice identifier is used for indicating the identifier of at least one network slice supported by the resident cell, the first network slice identifier is used for indicating the identifier of at least one network slice contained in the first network slice information, and the adjacent cell network slice identifier is used for indicating the identifier of at least one network slice supported by at least one adjacent cell of the resident cell.
The method according to claim 1, 2 or 4, wherein the terminal device performs cell reselection according to the first network slice information and the second network slice information, comprising:

The terminal equipment performs cell reselection when the number of network slices of the intersection of the resident cell network slice identifier and the first network slice identifier is equal to the number of network slices of the intersection of at least one adjacent cell network slice identifier and the first network slice identifier, and the link quality of the resident cell is lower than the link quality of the at least one adjacent cell; the resident cell network slice identifier is used for indicating the identifier of at least one network slice supported by the resident cell, the first network slice identifier is used for indicating the identifier of at least one network slice contained in the first network slice information, and the adjacent cell network slice identifier is used for indicating the identifier of at least one network slice supported by at least one adjacent cell of the resident cell.
The method according to claim 6 or 7, characterized in that the terminal device performs cell reselection, comprising:

and the terminal equipment selects the neighbor cell with the largest network slice number of the intersection of the neighbor cell network slice identifier and the first network slice identifier from the at least one neighbor cell to reside.
The method according to claim 9, wherein the terminal device performs cell reselection, comprising:

In case the number of network slices of the intersection of a plurality of said neighbor network slice identities and said first network slice identity is the largest,

the terminal equipment selects a neighbor cell with the highest link quality from the neighbor cells to reside; or the terminal equipment selects the neighbor cell with the highest priority from the neighbor cells to reside.
The method of claim 8, wherein the terminal device performs cell reselection, comprising:

the terminal equipment selects a neighbor cell with the highest link quality from the at least one neighbor cell to reside; or the terminal equipment selects the adjacent cell with the highest priority from the at least one adjacent cell to reside.
A terminal device comprising a processing unit and a communication unit, wherein,

the processing unit is used for determining first network slice information, and the first network slice information comprises an identification of at least one network slice;

the communication unit is communicatively coupled with the processing unit and is used for receiving second network slice information sent by a resident cell, wherein the second network slice information comprises the identification of at least one network slice;

The processing unit is further configured to perform cell reselection according to the first network slice information and the second network slice information.
The terminal device of claim 12, wherein the first network slice information is used to indicate an identity of at least one network slice to which the at least one service to be initiated by the terminal device belongs.
The terminal device of claim 12, wherein the second network slice information comprises an identification of at least one network slice supported by the camping cell.
The terminal device of claim 12, wherein the second network slice information comprises an identification of at least one network slice supported by the camped cell and an identification of at least one network slice supported by at least one neighbor cell of the camped cell.
The terminal device according to any of the claims 12 to 14, wherein the processing unit performs cell reselection based on the first network slice information and the second network slice information, comprising:

the processing unit performs cell reselection when the resident cell network slice identifier does not contain the first network slice identifier; wherein the resident cell network slice identifier is used for indicating an identifier of at least one network slice contained in the second network slice information, and the first network slice identifier is used for indicating an identifier of at least one network slice contained in the first network slice information.
The terminal device according to claim 12, 13 or 15, wherein the processing unit performs cell reselection according to the first network slice information and the second network slice information, comprising:

the processing unit performs cell reselection in case the resident cell network slice identity does not comprise the first network slice identity and at least one neighboring cell network slice identity comprises the first network slice identity partially or completely; the resident cell network slice identifier is used for indicating the identifier of at least one network slice supported by the resident cell, the first network slice identifier is used for indicating the identifier of at least one network slice contained in the first network slice information, and the adjacent cell network slice identifier is used for indicating the identifier of at least one network slice supported by one adjacent cell of the resident cell.
The terminal device according to claim 12, 13 or 15, wherein the processing unit performs cell reselection according to the first network slice information and the second network slice information, comprising:

the processing unit performs cell reselection in case the resident cell network slice identification portion comprises a first network slice identification and the number of network slices of the intersection of at least one neighbor cell network slice identification with the first network slice identification is greater than the number of network slices of the intersection of the resident cell network slice identification with the first network slice identification; the resident cell network slice identifier is used for indicating the identifier of at least one network slice supported by the resident cell, the first network slice identifier is used for indicating the identifier of at least one network slice contained in the first network slice information, and the adjacent cell network slice identifier is used for indicating the identifier of at least one network slice supported by at least one adjacent cell of the resident cell.
The terminal device according to claim 12, 13 or 15, wherein the processing unit performs cell reselection according to the first network slice information and the second network slice information, comprising:

the processing unit performs cell reselection in case the number of network slices of the intersection of the resident cell network slice identity and the first network slice identity is equal to the number of network slices of the intersection of the at least one neighboring cell network slice identity and the first network slice identity, and the link quality of the resident cell is lower than the link quality of the at least one neighboring cell; the resident cell network slice identifier is used for indicating the identifier of at least one network slice supported by the resident cell, the first network slice identifier is used for indicating the identifier of at least one network slice contained in the first network slice information, and the adjacent cell network slice identifier is used for indicating the identifier of at least one network slice supported by at least one adjacent cell of the resident cell.
The terminal device according to claim 17 or 18, wherein the processing unit performs cell reselection, comprising:

and the processing unit selects the neighbor cell with the largest network slice number of the intersection of the neighbor cell network slice identifier and the first network slice identifier from the at least one neighbor cell to reside.
The terminal device of claim 20, wherein the processing unit performs cell reselection, comprising:

in case the number of network slices of the intersection of a plurality of said neighbor network slice identities and said first network slice identity is the largest,

the processing unit selects a neighboring cell with the highest link quality from the plurality of neighboring cells to reside; or the terminal equipment selects the neighbor cell with the highest priority from the neighbor cells to reside.
The terminal device of claim 19, wherein the processing unit performs cell reselection, comprising:

the processing unit selects a neighbor cell with the highest link quality from the at least one neighbor cell to reside; or the terminal equipment selects the adjacent cell with the highest priority from the at least one adjacent cell to reside.
A communication device, comprising: a processor and a memory communicatively coupled, the memory storing program instructions that when executed by the processor implement a cell selection method as claimed in any one of claims 1 to 11.
A chip comprising logic circuitry for communicating with modules external to the chip and an input-output interface for running a computer program or instructions to implement a method as claimed in any one of claims 1 to 11.
A computer readable storage medium, characterized in that the computer readable storage medium stores a computer program comprising program instructions which, when executed by a communication device, cause the communication device to perform the method of any of claims 1 to 11.