Network search method and apparatus

Abstract

The present application relates to the technical field of communications, and in particular to a network search method and apparatus, in order to improve the network search efficiency of terminal devices, reduce the power consumption of the terminal devices, and improve the user experience. The method comprises: receiving access technology information supported or not supported by a first PLMN; and on the basis of a current second location of a terminal device, a previous first location of the terminal device, and the access technology information supported or not supported by the first PLMN, performing cell selection or searching for the first PLMN, the first location being the location of the terminal device when the terminal device receives the access technology information supported or not supported by the first PLMN.

Description

A method and apparatus for searching a network

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410987354.3, filed on July 22, 2024, entitled "A Method and Apparatus for Searching Nets", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of communication technology, and in particular to a network searching method and apparatus. Background Technology

[0004] After a terminal device powers on or loses network access, it needs to perform a network search (also known as cell selection or network selection). This search involves two parts: Public Land Mobile Network (PLMN) selection and access technology selection. PLMN selection follows a specific order, such as Registered PLMN (RPLMN), Equivalent PLMN (EPLMN), Equivalent Home PLMN (EHPLMN), Home PLMN (HPLMN), User-Controlled PLMN Selector with Access Technology (UPLMN), Operator-Controlled PLMN Selector with Access Technology (OPLMN), other high-quality PLMNs, and other low-quality PLMNs. Once a PLMN is selected, if no access technology is specified for that PLMN, the terminal device's non-access stratum (NAS) only provides the PLMN to the access stratum (AS) for cell selection. The AS layer needs to try all access technologies under the PLMN in descending order of priority, from 5G, 4G, 3G, to 2G. In future communication networks, it may be necessary to try even more access technologies until a suitable cell is found to initiate registration. Alternatively, when the AS layer searches for a given PLMN, it may also try all access technologies under that PLMN in descending order of priority, from 5G, 4G, 3G, to 2G.

[0005] However, PLMN support for access technologies may vary across different geographical areas. If a terminal device tries different access technologies sequentially after powering on or losing network connectivity, searching for frequencies, the entire network search process may be time-consuming, wasting terminal device resources and impacting user experience. For example, in areas where operators have not deployed 5G networks, if a terminal device tries different access technologies from that operator's PLMN sequentially after powering on or losing network connectivity, it will still attempt to search for a 5G network, wasting terminal device resources and lengthening the entire network search process, thus affecting user experience. Summary of the Invention

[0006] This application provides a network searching method and apparatus to improve the network searching efficiency of terminal devices, save power consumption of terminal devices, and enhance user experience.

[0007] Firstly, embodiments of this application provide a network search method. This method can be executed by a terminal device. The terminal device can refer to the terminal device itself, a processor, module, chip, or chip system implementing the method within the terminal device, or a logical node, logical module, or software capable of implementing all or part of the terminal device's functions. The method includes: receiving first access technology information (whether supported or not supported by a first PLMN); and performing cell selection or searching for a first PLMN based on the terminal device's current second location, its previous first location, and the first access technology information. The first location is the terminal device's location when the first access technology information was received.

[0008] Using the above method, the network side (such as the access network side or the core network side) can provide the terminal device with information on whether the first PLMN supports or does not support the first access technology. This allows the terminal device to prioritize searching for access technologies supported by the first PLMN based on its location, which helps improve the success rate of network search, reduce unnecessary attempts, and thus improve the efficiency of network search for the terminal device, save power consumption of the terminal device, and enhance the user experience.

[0009] In one possible design, cell selection or searching for a first PLMN is performed based on the terminal device's current second location, the terminal device's previous first location, and first access technology information, including: if the distance between the second location and the first location is less than or equal to a first value, cell selection or searching for a first PLMN is performed based on the first access technology information.

[0010] Through the above design, when the distance between the second location and the first location is less than or equal to a first value, the terminal device can perform cell selection or search for the first PLMN based on the first access technology information supported or not supported by the first PLMN. This can reduce the problem that the access technology information supported or not supported by the first PLMN at the current second location of the terminal device may be inconsistent with the first access technology information obtained by the terminal device at the previous first location due to the large movement distance of the terminal device, thus affecting the terminal device's network search.

[0011] In one possible design, the method further includes: receiving information on whether a second access technology is supported or not supported by a first PLMN, wherein the effective areas of the first access technology information and the second access technology information are different; and performing cell selection or searching for a first PLMN based on a second location, a third location prior to the terminal device, and the second access technology information, wherein the third location is the location of the terminal device when the second access technology information is received.

[0012] The above design enables terminal devices to receive access technology information applicable to different regions. Based on this information, they can perform cell selection or search for the first PLMN, which helps improve the efficiency and success rate of network search for terminal devices.

[0013] In one possible design, cell selection or searching for a first PLMN is performed based on a second location, a third location prior to the terminal device, and second access technology information, including: if the distance between the second location and the third location is less than or equal to a second value, cell selection or searching for a first PLMN is performed based on the second access technology information.

[0014] Through the above design, when the distance between the second and third locations is less than or equal to the second value, the terminal device can perform cell selection or search for the first PLMN based on the second access technology information supported or not supported by the first PLMN. This can reduce the problem that the access technology information supported or not supported by the first PLMN at the current second location of the terminal device may be inconsistent with the second access technology information obtained by the terminal device at the previous third location due to the excessive movement distance of the terminal device, thus affecting the terminal device's network search.

[0015] In one possible design, the first access technology information comes from the access network equipment; or, the first access technology information comes from the core network equipment.

[0016] The above design enables access network devices (such as access network devices in the first PLMN cell or the cell of the equivalent PLMN of the first PLMN) to send information about whether the first PLMN supports or does not support the first access technology through broadcasting or other means, which can reduce the signaling overhead caused by sending the first access technology information; it also enables core network devices to provide information about whether the first PLMN supports or does not support the first access technology to terminal devices, so that the core network can control the network search behavior of terminal devices.

[0017] In one possible design, the second access technology information comes from the access network equipment; or, the second access technology information comes from the core network equipment.

[0018] The above design allows access network devices (such as those in the first PLMN cell or an equivalent PLMN cell) to broadcast information about whether the first PLMN supports or does not support a second access technology, thereby reducing signaling overhead. It also allows core network devices to provide terminal devices with information about whether the first PLMN supports or does not support a second access technology, enabling the core network to control the network search behavior of the terminal devices.

[0019] In one possible design, the first value is determined based on a first region, which is a neighboring cell, tracking area (TA), or registration area (RA) corresponding to the terminal device. Similarly, the second value is determined based on a second region, which is a neighboring cell, TA, or RA corresponding to the terminal device, and the second region is different from the first region.

[0020] Through the above design, the terminal device can determine the first value (or second value) based on the effective area of ​​the first access technology information (or second access technology information) supported or not supported by the first PLMN. This avoids the terminal device from still searching for the network based on the previously obtained first access technology information (or second access technology information) after moving out of the effective area of ​​the first access technology information (or second access technology information) supported or not supported by the first PLMN, which would affect the reliability of the terminal device's network search.

[0021] In one possible design, if the first access technology information is valid in a neighboring cell, the first value is a first threshold for the corresponding neighboring cell; if the first access technology information is valid in a TA, the first value is a second threshold for the corresponding TA; if the first access technology information is valid in an RA, the first value is a third threshold for the corresponding RA. Similarly, if the second access technology information is valid in a neighboring cell, the second value is a first threshold for the corresponding neighboring cell; if the second access technology information is valid in a TA, the second value is a second threshold for the corresponding TA; if the second access technology information is valid in an RA, the second value is a third threshold for the corresponding RA.

[0022] Through the above design, the corresponding threshold can be determined based on the effective area of ​​access technology information supported or not supported by the first PLMN, clarifying the application conditions of access technology information supported or not supported by the first PLMN, and improving the reliability of network search by terminal equipment.

[0023] In one possible design, the method further includes: receiving a first value from an access network device; or receiving a first value from a core network device.

[0024] In one possible design, the method further includes: receiving a second value from an access network device; or receiving a second value from a core network device.

[0025] The above design allows access network devices or core network devices to configure a first value or a second value for terminal devices, thereby controlling the network search behavior of terminal devices.

[0026] In one possible design, cell selection or searching for a first PLMN is performed based on the first access technology information, including: when performing cell selection, prioritizing the search for cells with access technologies supported by the first PLMN based on the first access technology information; or, when searching for a first PLMN, prioritizing the search for access technologies supported by the first PLMN based on the first access technology information.

[0027] The above design allows terminal devices to prioritize searching for access technologies supported by the first PLMN (or cells supported by the first PLMN), which helps improve the efficiency of terminal devices when performing cell selection or searching for the first PLMN.

[0028] In one possible design, the first PLMN is the registered PLMN of the terminal device and / or an equivalent PLMN of the registered PLMN.

[0029] Through the above design, the first PLMN can be the registered PLMN and / or the equivalent PLMN of the registered PLMN for the terminal device. By providing the terminal device with information on the access technologies supported or not supported by the registered PLMN and / or the equivalent PLMN, unnecessary attempts by the terminal device when performing cell selection or searching for available PLMNs can be reduced, thereby improving the network search efficiency of the terminal device.

[0030] Secondly, embodiments of this application provide a network search method. This method can be executed by a first device, which can refer to an access network device or a core network device, or a processor, module, chip, or chip system within the access network device or core network device that implements the method. It can also be a logical node, logical module, or software capable of implementing all or part of the functions of the access network device or core network device. The method includes: obtaining information on whether a first access technology is supported or not supported by a first PLMN; the first access technology information is used by the terminal device to perform cell selection or search for the first PLMN; and sending the first access technology information.

[0031] In one possible design, information on whether a second access technology is supported or not by the first PLMN is obtained. This second access technology information is used by the terminal device to perform cell selection or search for the first PLMN. The effective areas of the second access technology information and the first access technology information are different. The second access technology information is then sent.

[0032] In one possible design, the first device includes an access network device and / or a core network device, and transmits second access technology information, including: the access network device transmitting the second access technology information; or, the core network device transmitting the second access technology information.

[0033] In one possible design, the first device includes an access network device and / or a core network device, and sends first access technology information, including: the access network device sending the first access technology information; or, the core network device sending the first access technology information.

[0034] In one possible design, the method further includes: sending a first value, which is used by the terminal device to determine whether to perform cell selection or search for a first PLMN based on the first access technology information, depending on whether the current second location is less than or equal to the previous first location. The first location is the location of the terminal device when receiving the first access technology information.

[0035] In one possible design, the first value is determined based on a first region, which is the neighboring cell, TA, or RA corresponding to the terminal device.

[0036] In one possible design, if the first access technology information is valid in a neighboring cell, the first value is the first threshold of the corresponding neighboring cell; if the first access technology information is valid in a TA, the first value is the second threshold of the corresponding TA; if the first access technology information is valid in an RA, the first value is the third threshold of the corresponding RA.

[0037] In one possible design, the method further includes: sending a second value, which is used by the terminal device to determine whether to perform cell selection or search for a second PLMN based on the second access technology information, depending on whether the current second location is less than or equal to the previous third location. The third location is the location of the terminal device when receiving the second access technology information.

[0038] In one possible design, the second value is determined based on a second region, which is the neighboring cell, TA, or RA corresponding to the terminal device.

[0039] In one possible design, if the second access technology information is valid in a neighboring cell, the second value is the first threshold of the corresponding neighboring cell; if the second access technology information is valid in a TA, the second value is the second threshold of the corresponding TA; if the second access technology information is valid in an RA, the second value is the third threshold of the corresponding RA.

[0040] In one possible design, the first PLMN is the registered PLMN of the terminal device and / or an equivalent PLMN of the registered PLMN.

[0041] Thirdly, embodiments of this application provide a communication device that has the function of implementing the methods described in the first or second aspect above. This function can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions, such as an interface unit and a processing unit.

[0042] In one possible design, the device can be a chip or an integrated circuit.

[0043] In one possible design, the device includes a memory and a processor, the memory for storing instructions executed by the processor, and when the instructions are executed by the processor, the device can perform the method of the first aspect or the second aspect.

[0044] Fourthly, embodiments of this application provide a communication device, which includes an interface circuit and a processor, with the processor and the interface circuit coupled to each other. The interface circuit is used for inputting and / or outputting signals, and the processor uses logic circuits or executing instructions to implement the methods of the first or second aspect described above. It is understood that the interface circuit can be a transceiver, a transceiver device, or an input / output interface.

[0045] Optionally, the communication device may also include a memory for storing instructions executed by the processor, or storing input data required by the processor to execute instructions, or storing data generated after the processor executes instructions. The memory may be a physically independent unit, or it may be coupled to the processor, or the processor may include the memory (i.e., the processor and the memory are integrated together).

[0046] In one possible implementation, the communication device is a chip.

[0047] Fifthly, embodiments of this application provide a communication system, which includes a terminal device and a first device. The terminal device is used to implement the method described in the first aspect; the first device is used to implement the method described in the second aspect.

[0048] In a sixth aspect, embodiments of this application provide a computer-readable storage medium storing a computer program or instructions, which, when executed by a processor, can implement the methods described in the first or second aspect.

[0049] In a seventh aspect, embodiments of this application also provide a computer program product, including a computer program or instructions, which, when executed by a processor, can implement the methods described in the first or second aspect.

[0050] Eighthly, embodiments of this application also provide a chip system including a processor, the processor being coupled to a memory, the memory being used to store programs or instructions, and when the program or instructions are executed by the processor, the methods of the first or second aspect described above can be implemented.

[0051] The technical effects achievable by aspects two through eight above are similar to those achievable by aspect one above, and will not be repeated here. Attached Figure Description

[0052] Figure 1A is a schematic diagram of the architecture of the communication system provided in an embodiment of this application;

[0053] Figure 1B is a schematic diagram of the chip of the terminal device provided in the embodiment of this application;

[0054] Figures 2, 4, 5, 6, 7, and 8 are schematic diagrams of the net-searching method provided in the embodiments of this application;

[0055] Figures 3A, 3B, and 3C are schematic diagrams of the neighboring cell range provided in the embodiments of this application;

[0056] Figures 9 and 10 are schematic diagrams of the communication device provided in the embodiments of this application. Detailed Implementation

[0057] This application provides a method and apparatus for searching a network. The method and apparatus are based on the same inventive concept. Since the principles by which the method and apparatus solve the problem are similar, their implementations can be mutually referenced, and repeated details will not be repeated.

[0058] Figure 1A illustrates a possible, non-limiting architecture of a communication system to which this application applies. The communication system includes: terminal equipment (user equipment (UE) in Figure 1A as an example), an operator network, and a data network (DN). The operator network may include one or more of the following network elements (or devices): radio access network (RAN) devices, user plane function (UPF) network elements, access and mobility management function (AMF) network elements, session management function (SMF) network elements, policy control function (PCF) network elements, application function (AF) network elements, network slice selection function (NSSF) network elements, authentication server function (AUSF) network elements, user data management (UDM) network elements, network slice admission control function (NSACF) network elements, and network slice-specific authentication and authorization function (NSSAAF) network elements. In the aforementioned operator networks, network elements or devices other than (R)AN devices can be referred to as core network (CN) network elements or CN devices.

[0059] Terminal devices, also known as terminals, user interfaces (UEs), mobile stations, or mobile terminals, can be devices used to provide voice or data connectivity to users, or they can be Internet of Things (IoT) devices. Terminal devices can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), the Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, and smart cities. Terminal devices can be: mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices (such as smartwatches, smart bracelets, pedometers, smart glasses, etc.), in-vehicle equipment (such as cars, bicycles, electric vehicles, airplanes, ships, trains, high-speed trains, etc.), satellite terminals, virtual reality (VR) devices, augmented reality (AR) devices, smart point of sale (POS) machines, customer-premises equipment (CPE), light user equipment (UE), reduced capability user equipment (REDCAP UE), wireless terminals in industrial control, smart home devices (such as refrigerators, televisions, air conditioners, electricity meters, etc.), smart robots, robotic arms, workshop equipment, wireless terminals in autonomous driving, wireless terminals in telemedicine, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, or wireless terminals in smart homes, and flying equipment (such as smart robots, hot air balloons, drones, airplanes), etc. The terminal device can also be a vehicle device, such as a complete vehicle device, an in-vehicle module, an in-vehicle chip, an on-board unit (OBU), or a telematics box (T-BOX). The terminal device can also be other devices with terminal functions; for example, it can be a device that performs terminal functions in D2D communication. The embodiments of this application do not limit the device form of the terminal device.

[0060] Figure 1B is a schematic diagram of a chip for a terminal device provided in an embodiment of this application. This chip can also be called a communication chip. As shown in Figure 1B, the chip may include at least one of the following: a baseband subsystem, a radio frequency (RF) subsystem, a power supply subsystem, or peripherals. The baseband subsystem may implement one or more functions such as application layer processing, external interface, and layer 3 (L3) / layer 2 (L2) / layer 1 (L1) communication protocol processing. The RF subsystem may include an RF front-end and an antenna, mainly implementing one or more functions such as conversion of spatial electromagnetic waves to electrical signals, signal amplification, and signal filtering. The RF subsystem may also be connected to the baseband subsystem to realize frequency conversion of analog signals and correction of nonlinear distortion. The power supply subsystem, also called a power management subsystem, can realize power management functions. For example, the power supply subsystem may be connected to the baseband subsystem and the RF subsystem to manage the power supply of the baseband subsystem and the RF subsystem. Peripherals may include memory and / or external interfaces to realize communication between the chip and external devices.

[0061] (R)AN equipment, also known as access network equipment, RAN node, access network node, network equipment, etc., is part of a communication network used to help terminal devices achieve wireless access. In one possible scenario, (R)AN equipment can be a base station, an evolved NodeB (eNodeB), an access point (AP), a transmission reception point (TRP), a next-generation NodeB (gNB), or a base station in a future mobile communication network. (R)AN equipment can be a macro base station, a micro base station or indoor station, a relay node or donor node, or a radio controller in a cloud radio access network (CRAN) scenario. Optionally, (R)AN equipment can also be a server, wearable device, vehicle or in-vehicle equipment, etc. For example, the access network equipment in vehicle to everything (V2X) technology can be a roadside unit (RSU). All or part of the functionality of the (R)AN) device in this application can also be implemented through software functions running on hardware, or through virtualization functions instantiated on a platform (e.g., a cloud platform). The (R)AN) device in this application can also be a logical node, logical module, or software capable of implementing all or part of the (R)AN) device functionality.

[0062] In another possible scenario, multiple (R)AN devices collaborate to assist terminal devices in achieving wireless access, with each (R)AN device performing a portion of the base station's functions. For example, (R)AN devices can be central units (CUs), distributed units (DUs), CU-control plane (CPs), CU-user plane (UPs), or radio units (RUs), etc. CUs and DUs can be set up separately or included in the same network element, such as a baseband unit (BBU). RUs can be included in radio equipment or radio units, such as remote radio units (RRUs), active antenna units (AAUs), or remote radio heads (RRHs).

[0063] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an open access network (open RAN, O-RAN, or ORAN) system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software modules and hardware modules.

[0064] The AMF (Access Controller Function) is primarily responsible for user mobility management, access authentication / authorization, and signaling processing in mobile communication systems. For example, AMF functions may include: access control, UE location update, UE registration and deregistration, attach and detach, SMF selection, NAS layer signaling security termination, UE mobility management, N1 / N2 interface signaling transmission, access authentication and authorization, etc. Furthermore, the AMF is also responsible for transmitting user policies between the UE and the PCF (Programmable Controller Function).

[0065] The SMF (Service Provider Function) network element, or SMF for short, is primarily responsible for session management in mobile communication systems, such as session establishment, modification, and release. Specifically, SMF functions include: UPF selection, UPF redirection, Internet Protocol (IP) address allocation, bearer establishment, modification, and release, and Quality of Service (QoS) control.

[0066] UPF (User PF) network element: This element is responsible for forwarding and receiving user data in terminal devices. It can receive user data from the data network and transmit it to the terminal device through the access network equipment. The UPF network element can also receive user data from the terminal device through the access network equipment and forward it to the data network. The transmission resources and scheduling functions that provide services to the terminal device within the UPF network element are managed and controlled by the SMF (Simplified Management PF) network element.

[0067] The PCF network element, or PCF for short, is mainly responsible for providing a unified policy framework to control network behavior, providing policy rules to other control plane network elements, and obtaining user subscription information related to the policy.

[0068] The AUSF network element, which can be abbreviated as AUSF, is mainly responsible for providing authentication functions and supporting authentication for 3rd generation partnership project (3GPP) access and non-3GPP access.

[0069] UDM network elements, or UDM for short, are mainly responsible for storing and managing UE subscription data, user access authorization, user service network element registration management, and user identification processing (such as storing and managing user permanent identity identifiers).

[0070] The NSSF network element, which can be abbreviated as NSSF, is mainly responsible for selecting network slices.

[0071] An AF (Active Front-End) network element, often abbreviated as AF, primarily transmits the application's requests to the network side. It supports interaction with other network elements in the core network to provide services, such as influencing data routing decisions, policy control functions, or providing third-party services to the network side. An AF network element can be a third-party functional entity or an application server deployed by the operator.

[0072] The NSSAAF network element, which can be abbreviated as NSSAAF, mainly supports authentication and authorization for network slices.

[0073] The NSACF network element, which can be abbreviated as NSACF, mainly monitors and controls the number of UEs registered on each network slice and monitors and controls the number of protocol data unit (PDU) sessions established on each network slice.

[0074] In Figure 1A, N1, N2, N3, N4, N5, N6, N7, N8, N9, N10, N11, N12, N13, N14, N15, N22, N58, N59, N80, and N81 are interface sequence numbers. For example, the meaning of these interface sequence numbers can be found in the definitions in the 3GPP standard protocol.

[0075] It should be understood that the network elements mentioned above in CN can be network components implemented on dedicated hardware, software instances running on dedicated hardware, or instances of virtualized functions on a virtualization platform (such as a cloud platform). This application does not limit the distribution of the network elements in the communication system. Optionally, the network elements can be deployed in different physical devices, or multiple network elements can be integrated into the same physical device.

[0076] It should be noted that the communication system shown in Figure 1A does not constitute a limitation on the communication systems to which the embodiments of this application can be applied. The network search method provided in the embodiments of this application can be applied to various communication systems (or access technologies), such as: Long Term Evolution (LTE) communication system, 5G communication system, Future Communication System, and communication systems that integrate two or more of the above.

[0077] The embodiments of this application do not limit the names of each network element in the communication system. For example, in communication systems of different standards (or access technologies), each network element may have other names; for another example, when multiple network elements are integrated into the same physical device, the physical device may also have other names.

[0078] To facilitate understanding by those skilled in the art, some terms used in the embodiments of this application are explained below.

[0079] 1) Network loss: Network loss refers to the loss of network connection, interruption of network connection and inability to access the Internet, or failure to register on a cell. For example, if a terminal device was previously registered on a cell, but later moved, cell reselection failed and a suitable cell could not be found to register on.

[0080] 2) A PLMN is a public mobile network established and operated by a specific operator in a country or region for the purpose of providing terrestrial mobile communication services to the public. This network can interconnect with other communication networks such as the Public Switched Telephone Network (PSTN) to form a nationwide or regional communication network. The PLMN's network identifier (which can be simply called the PLMN identifier (ID)) consists of a mobile country code (MCC) and a mobile network code (MNC).

[0081] Different types of PLMNs have different priorities. When selecting a PLMN, the terminal device can select the PLMN in a certain order, such as RPLMN, EPLMN, EHPLMN / HPLMN, UPLMN, OPLMN, other high-quality signal PLMNs, and other low-quality signal PLMNs.

[0082] 3) Wireless access technology, also known as network standard, can include the following types of technology: 5G, 4G, 3G, 2G, etc. With the development of wireless access technology, other wireless technologies may also exist in future networks, such as 6G and 7G.

[0083] 4) Location Target (TA): TA is a concept introduced for location management of terminal devices. TA is a cell-level configuration; multiple cells can be configured with the same TA (i.e., belong to the same TA), and a cell can only belong to one TA.

[0084] 5) RA: An RA includes a set of TAs (or a list of tracing area identities (TAIs) corresponding to a set of TAs). This set of TAs is assigned to terminal devices by the network (such as the core network) for mobility management. When a terminal device leaves the RA in idle mode, it needs to register; when the terminal device is in idle mode, the network needs to page the terminal device, paging it from the TA list included in the RA.

[0085] 6) Sending / receiving information. In this application, "sending information" can be understood as one device sending information to another device, or it can also be understood as one logic module within a device sending information to another logic module. For example, "device A sending information" can be understood as device A sending information to another device (device B), or it can be understood as logic module 1 in device A sending information to logic module 2 in device A.

[0086] In this application, "receiving information" can be understood as one device receiving information from another device, or it can also be understood as a logical module within a device receiving information from another logical module. For example, "device A receives information" can be understood as device A receiving information from another device (such as device B), or it can be understood as logical module 1 in device A receiving information from logical module 2 in device A.

[0087] In this application, the phrase "sending information to... (e.g., device B)" or the related illustrations in the accompanying drawings can be understood as the destination of the information being device B. This can include sending information directly or indirectly to device B. Similarly, the phrase "receiving information from... (e.g., device A)," "receiving information from... (e.g., device A)," or "receiving information sent by (e.g., device A)," or the related illustrations in the accompanying drawings, can be understood as the source of the information being device A. This can include receiving information directly or indirectly from device A. Information may undergo necessary processing between the source and destination, such as format changes, but the destination can understand the valid information from the source. Similar expressions in this application can be interpreted similarly, and will not be elaborated further here.

[0088] Currently, after a terminal device powers on or loses network access, it needs to perform a network search (also known as cell selection or network selection). This search involves two parts: PLMN selection and access technology selection. Once a PLMN is selected, if no specific access technology is specified for that PLMN, the terminal device's NAS only provides the PLMN (without PLMN access technology) to the AS for cell selection. The AS layer needs to try all access technologies under that PLMN in descending order of priority (5G, 4G, 3G, 2G). In future networks, even more access technologies may need to be tried until a suitable cell is found and registration is initiated.

[0089] However, PLMN support for access technologies may vary across different geographical areas. If a terminal device tries different access technologies sequentially after powering on or losing network connectivity, searching for frequencies, the entire network search process may be time-consuming, wasting terminal device resources and impacting user experience. For example, in areas where operators haven't deployed 5G networks, a terminal device, after powering on or losing network connectivity, will still attempt to search for 5G networks by trying different access technologies from that operator's PLMN, wasting terminal device resources and lengthening the search process, thus affecting user experience. Similarly, if operators discontinue or withdraw from the market using low-level access technologies like 2G and 3G in certain areas, even if no suitable cells or available frequencies are available for the 5G or 4G networks of that operator's PLMN, the terminal device will still try the 3G and 2G networks, wasting terminal device resources and lengthening the search process, thus affecting user experience.

[0090] Based on this, embodiments of this application provide a network searching method and apparatus to improve the network searching efficiency of terminal devices, save power consumption of terminal devices, and enhance user experience. The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0091] Additionally, it should be understood that the ordinal numbers such as "first" and "second" mentioned in the embodiments of this application are used to distinguish multiple objects, and are not used to limit the size, content, order, timing, priority, or importance of multiple objects. For example, the first threshold and the second threshold do not indicate a difference in priority or importance corresponding to these two thresholds.

[0092] In this application embodiment, the number of nouns, unless otherwise specified, refers to "singular nouns or plural nouns," that is, "one or more." "At least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after are in an "or" relationship. For example, A / B means: A or B. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c means: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

[0093] Figure 2 is a schematic diagram of one of the network search methods provided in the embodiments of this application. Figure 2 illustrates the method using a terminal device and a first device as the execution entities in the interactive illustration. The terminal device can be a module applied to the terminal device, such as a circuit, chip, chip system, or processor; it can also be a logical node, logical module, or software capable of implementing all or part of the terminal device's functions. The first device can be an access network device (such as a base station) or a core network device (such as an AMF); it can also be a module applied to the access network device (or core network device), such as a circuit, chip, chip system, or processor; or it can be a logical node, logical module, or software capable of implementing all or part of the access network device (or core network device)'s functions. The method includes:

[0094] S201: The first device sends information about whether the first PLMN supports or does not support a first access technology, and the terminal device receives the information about whether the first PLMN supports or does not support a first access technology.

[0095] In this embodiment, the first device can be an access network device, a core network device, etc. The first device can obtain information about the first access technology supported or not supported by the first PLMN, and send the first access technology information to the terminal device. The first PLMN can be the PLMN where the first device is located and / or a PLMN equivalent to the PLMN where the first device is located.

[0096] Taking the first device as an access network device as an example, the access network device can obtain information on the first access technology that the first PLMN supports or does not support through at least one of the following methods, and send the first access technology information to the terminal device.

[0097] Method A1: The access network device can obtain information about the first access technology supported or not supported by the first PLMN in neighboring cells, and send the first access technology information to the terminal device. The neighboring cells can be determined based on the location of the access network device, or based on the location of the cells included by the access network device. The cells included by the access network device can also be understood as cells that the access network device provides services to, or cells that the access network device provides coverage for, etc.

[0098] Taking the determination of neighboring cells based on the location of the access network device as an example, as shown in Figure 3A, a circular area with the location of the access network device as the center and a radius of R can be used as a neighboring cell, or a rectangular area with the location of the access network device as the center and a side length of 2R can be used as a neighboring cell.

[0099] Referring to Figure 3B, the three hexagonal coverage areas surrounding the location of the access network device can be considered as neighboring cells.

[0100] Referring to Figure 3C, the hexagonal coverage area where the access network device is located can be taken as the center, and the hexagonal coverage area and the other 6 hexagonal coverage areas around the hexagonal coverage area can be regarded as neighboring cells.

[0101] Of course, neighboring cells can also be determined based on the location of the cells included in the access network equipment (taking cell 1 as an example). For example, a circular area with radius R centered on the center of cell 1 can be considered as a neighboring cell; the three hexagonal coverage areas surrounding the center of cell 1 can also be considered as neighboring cells; or the hexagonal coverage area centered on the center of cell 1, along with the other six hexagonal coverage areas surrounding it, can be considered as neighboring cells, and so on.

[0102] It should be understood that the above are only some examples of neighbor cell division. This application does not limit the method of neighbor cell division. For example, the area consisting of the cell included in the access network device (taking cell 1 as an example) and the neighboring cells of that cell can also be regarded as a neighbor cell; one or more cells included in the access network device can be regarded as a neighbor cell, and so on. In the embodiments of this application, the coverage area of ​​the neighbor cell can be the same as or different from the coverage area of ​​the neighboring cells of the cell included in the access network device. This application does not limit this.

[0103] Method A2: The access network device can obtain information about the first access technology (TA) that the first PLMN supports or does not support. The TA can be determined based on the location of the access network device or the location of the cells included in the access network device.

[0104] As an example: an access network device can obtain information about the first access technology that the first PLMN supports or does not support at the TA it is located in, based on its own TA.

[0105] It should be understood that the above-mentioned methods A1 and A2 are only possible examples of access network devices obtaining information on whether the first access technology is supported or not supported by the first PLMN. This application does not limit the methods by which access network devices obtain information on whether the first access technology is supported or not supported by the first PLMN.

[0106] For example, the access network device can also obtain information on whether the first access technology is supported or not supported by the first PLMN in the administrative or management area where the access network device is located, based on the administrative or management area division of the first PLMN (such as the street, county, city, etc.), and send it to the terminal device.

[0107] Additionally, it should be noted that after obtaining information on whether the first access technology is supported or not supported by the first PLMN, the access network device can send this information to the terminal device via broadcast, multicast, or other means within the cells included by the access network device.

[0108] As an example: the access network equipment includes cell 1. The access network equipment can send broadcast messages in cell 1 via broadcast. After the terminal equipment is camped in cell 1, it can receive the broadcast message, read the access technology information carried in the broadcast message (whether the first PLMN supports or does not support it), and store it. The broadcast message can be a system information block (SIB), etc.

[0109] Taking the first device as a core network device as an example, the core network device can obtain information on whether the first PLMN supports or does not support the first access technology through at least one of the following methods, and send the information on whether the first PLMN supports or does not support the first access technology to the terminal device.

[0110] Method B1: The core network equipment can obtain the first access technology information that the first PLMN supports or does not support in the TA corresponding to the terminal equipment, and send the first access technology information that the first PLMN supports or does not support in the TA to the terminal equipment.

[0111] As an example: After a terminal device initiates registration with the core network in the cell where it is camped, the core network device can determine the TA (i.e., the TA where the camped cell is located) corresponding to the terminal device based on the cell where the terminal device is camped, obtain the first access technology information that the first PLMN supports or does not support in the TA corresponding to the terminal device, and send the first access technology information that the first PLMN supports or does not support in the TA to the terminal device.

[0112] Method B2: The core network equipment can obtain the first access technology information that the first PLMN supports or does not support in the RA corresponding to the terminal equipment, and send the first access technology information that the first PLMN supports or does not support in the RA to the terminal equipment.

[0113] As an example: After the terminal device initiates registration with the core network in the cell where it is camped, the core network device can determine the RA (i.e., the RA where the camped cell is located) corresponding to the terminal device based on the cell where the terminal device is camped, obtain the first access technology information that the first PLMN supports or does not support in the RA corresponding to the terminal device, and send the first access technology information that the first PLMN supports or does not support in the RA to the terminal device.

[0114] It should be understood that the above-mentioned methods B1 and B2 are only possible examples of how the core network equipment obtains information on whether the first access technology is supported or not supported by the first PLMN. This application does not limit the methods by which the core network equipment obtains information on whether the first access technology is supported or not supported by the first PLMN.

[0115] For example, the core network equipment can also obtain information on whether the first access technology is supported or not supported by the first PLMN in the administrative or management area where the terminal equipment is stationed, based on the administrative or management area division of the first PLMN (such as the street, county, city, etc.), and send it to the terminal equipment.

[0116] For example, the core network device can send information about the first access technology supported or not supported by the first PLMN to the terminal device through NAS messages (such as registration acceptance messages or configuration update command (CUC) messages). The terminal device can receive and store the information about the first access technology supported or not supported by the first PLMN.

[0117] In some implementations, when a terminal device receives information about whether a first access technology is supported or not supported by a first PLMN from a first device, it can also obtain the first location of the terminal device at the time of receiving the information about whether a first access technology is supported or not supported by a first PLMN from a first device.

[0118] As an example: When a terminal device receives information about a first access technology that is supported or not supported by the first PLMN from the first device, it can read its own first location through the Global Navigation Satellite System (GNSS) module set in the terminal device, or it can determine its own first location based on interaction with access network devices, etc., through positioning technologies such as Time of Arrival (TOA) positioning technology and Time Difference of Arrival (TDOA) positioning technology.

[0119] S202: The terminal device performs cell selection or searches for the first PLMN based on the terminal device's current second location, the terminal device's previous first location, and the first access technology information.

[0120] The first location refers to the location of the terminal device when receiving access technology information supported or unsupported by the first PLMN. Regarding the second location, the terminal device can read its own second location through a GNSS module, or it can determine its second location through positioning technologies such as TOA and TDOA based on interaction with access network devices. This application embodiment does not limit the method by which the terminal device obtains its second location.

[0121] In one possible implementation, after receiving information about whether the first access technology is supported or not by the first PLMN, the terminal device can perform cell selection or search for the first PLMN in situations such as when the terminal device loses network access due to movement, or when it needs to perform cell selection or search for the first PLMN after powering off.

[0122] As an example: When a terminal device is camped on cell 1 of the access network equipment, it receives information broadcast by the access network equipment in cell 1 that the first PLMN supports 5G and 4G in neighboring cells. After the terminal device loses network access due to mobility, it can perform cell selection according to the information broadcast by the access network equipment in cell 1 that the first PLMN supports 5G and 4G in neighboring cells, in the order of first trying the first PLMN 5G network and then the first PLMN 4G network. If an available cell is found, the terminal device initiates registration based on the found available cell.

[0123] In another possible implementation, the terminal device may, based on the received information about whether the first PLMN supports or does not support the first access technology, prioritize searching for cells with access technologies supported by the first PLMN when performing cell selection; or, prioritize searching for access technologies supported by the first PLMN when searching for the first PLMN.

[0124] As an example: When a terminal device is camped in cell 1 of an access network device, it receives information broadcast by the access network device in cell 1 that the first PLMN does not support 2G or 3G in neighboring cells. After the terminal device loses network access, it can determine that the first PLMN supports 5G and 4G in neighboring cells based on this information. It can then search for the first PLMN in the order of first trying the 5G network, then trying the 4G network. Because the first PLMN supports 5G and 4G but not 2G and 3G, if the terminal device cannot find a suitable cell or available frequency point to camp on in either the 5G or 4G network of the first PLMN, it can stop trying the 3G and 2G networks of the first PLMN and instead search for other PLMNs to improve network search efficiency.

[0125] For example, if the terminal device fails to find a cell or available frequency point to camp on in either the first PLMN 5G network or the 4G network, it can select other PLMNs according to the configured PLMN selection order. After selecting a PLMN, it can try all access technologies under that PLMN in descending order of priority, such as 5G, 4G, 3G, and 2G.

[0126] In one possible implementation, to avoid discrepancies between the access technology information supported or not supported by the first PLMN at the terminal device's current second location and the first access technology information obtained by the terminal device at its previous first location due to the large distance the terminal device has moved, thus affecting the accuracy of the terminal device's network search, the terminal device may determine that the distance between the second location and the first location is less than or equal to a first value before performing cell selection or searching for the first PLMN based on the first access technology information supported or not supported by the first PLMN.

[0127] The first value can be sent from the first device to the terminal device, or it can be pre-configured in the terminal device, or it can be determined by the terminal device based on the first access technology information supported or not supported by the received first PLMN, which is valid for the first area. This application does not limit the method of determining the first value. The first area can be at least one of the following: the neighboring cell, TA, or RA corresponding to the terminal device.

[0128] It is understandable that the first value can correspond to different values ​​depending on whether the first PLMN received by the terminal device supports or does not support the first access technology information and the effective first region.

[0129] For example: If the terminal device receives information from the first device about whether the first PLMN supports or does not support the first access technology in the neighboring cell, that is, the information about whether the first PLMN supports or does not support the first access technology is valid in the neighboring cell, the first value can be the first threshold of the corresponding neighboring cell. The first threshold can be sent by the first device to the terminal device, or it can be pre-configured in the terminal device, or it can be determined by the terminal device according to the neighboring cell (such as the radius of the coverage area of ​​the neighboring cell).

[0130] If the terminal device receives information from the first device about whether the first PLMN supports or does not support the first access technology in the TA, that is, the information about whether the first PLMN supports or does not support the first access technology is valid in the TA, the first value can be the second threshold corresponding to the TA. The second threshold can be sent by the first device to the terminal device, or it can be pre-configured in the terminal device, or it can be determined by the terminal device according to the TA (such as the radius of the TA coverage area).

[0131] If the terminal device receives information from the first device about whether the first PLMN supports or does not support the first access technology in the RA, that is, the information about whether the first PLMN supports or does not support the first access technology is valid in the RA, the first value can be the third threshold of the corresponding RA. The third threshold can be sent by the first device to the terminal device, or it can be pre-configured in the terminal device, or it can be determined by the terminal device according to the RA (such as the radius of the RA coverage area).

[0132] In some implementations, the first device may also send to the terminal device information on whether the first PLMN supports or does not support access technologies (such as second access technology information) in other areas (such as the second area) different from the first area. The terminal device may perform cell selection or search for the first PLMN based on the first access technology information that the first PLMN supports or does not support in the first area, and the first PLMN supports or does not support access technologies (such as second access technology information) in other areas (such as the second area).

[0133] It is understandable that if a terminal device receives multiple access technology information with different effective areas (or applicable areas), the terminal device can select cells or search for the first PLMN in order of increasing effective area to improve network search efficiency; of course, it can also select cells or search for the first PLMN in other orders, and this application does not limit this.

[0134] For example: If the terminal device receives information from the first device about whether the first PLMN supports or does not support a first access technology in a neighboring cell, and information about whether the first PLMN supports or does not support a second access technology in the RA, the terminal device may perform cell selection or search for the first PLMN in the following order: first, based on the information about whether the first PLMN supports or does not support a first access technology in a neighboring cell, and second, based on the information about whether the first PLMN supports or does not support a second access technology in the RA.

[0135] If the terminal device receives information from the first device about whether the first PLMN supports or does not support a first access technology in the TA and whether the first PLMN supports or does not support a second access technology in the RA, the terminal device may perform cell selection or search for the first PLMN in the following order: first, based on the information about whether the first PLMN supports or does not support a first access technology in the TA, and second, based on the information about whether the first PLMN supports or does not support a second access technology in the RA.

[0136] If the terminal device receives information from the first device about whether the first PLMN supports or does not support a first access technology in a neighboring cell, and information about whether the first PLMN supports or does not support a second access technology in a TA, the terminal device may perform cell selection or search for the first PLMN in the following order: first, based on the information about whether the first PLMN supports or does not support a first access technology in a neighboring cell, and second, based on the information about whether the first PLMN supports or does not support a second access technology in a TA.

[0137] In some implementations, before performing cell selection or searching for the first PLMN based on the second access technology information, the terminal device can also determine that the distance between the terminal device's current second location and the terminal device's third location when receiving the second access technology information is less than or equal to a second value. This second value can be determined based on a second region, which is the effective or applicable region of the second access technology information. The second region can be the neighboring cell, TA, or RA corresponding to the terminal device. The implementation of the terminal device obtaining the second value can refer to the implementation of obtaining the first value, and will not be elaborated further.

[0138] The embodiments in Figure 2 above will be described below, taking the first device as including access network equipment, AMF (AMF is core network equipment), or access network equipment and AMF as examples, in conjunction with the specific embodiments in Figures 4, 5, 6, 7 and 8.

[0139] Figure 4 is a second schematic diagram of the network search method provided in the embodiments of this application. In the embodiment shown in Figure 4, taking the first device as an access network device as an example, the method includes the following steps:

[0140] S401: The access network device sends information about whether the first PLMN supports or does not support a first access technology in a neighboring cell or TA, and correspondingly, the terminal device receives information about whether the first PLMN supports or does not support a first access technology in a neighboring cell or TA.

[0141] As an example: an access network device can broadcast a message in its cell. The broadcast message may include information about the first access technology that the first PLMN supports or does not support in neighboring cells or TAs. After the terminal device is camped in the cell of the access network device, it can monitor the broadcast message, obtain and store the information about the first access technology that the first PLMN supports or does not support in neighboring cells or TAs, and record the first location of the terminal device when it obtains the first access technology information. The first location can be read from the GNSS module of the terminal device.

[0142] When a terminal device loses network access due to movement, or is powered on after being powered off, and needs to perform cell selection or PLMN search, the terminal device can execute step S402.

[0143] S402: The terminal device performs cell selection or searches for the first PLMN based on the current second location, the previous first location, and the first access technology information of whether the first PLMN supports or does not support the first access technology in the neighboring cell or TA.

[0144] The terminal device can read its own second location through the GNSS module set in the terminal device, or it can determine its own second location through positioning technologies such as TOA positioning technology and TDOA positioning technology based on interaction with access network devices. In this embodiment of the application, the method by which the terminal device obtains its second location is not limited.

[0145] Taking the first access technology information included in the broadcast message as information on whether the first PLMN supports or does not support access technologies in neighboring cells as an example, the first value can be the first threshold of the corresponding neighboring cell. If a terminal device loses network access due to movement, or after being powered off and then powered on, and if the distance between the terminal device's current second location and its first location is less than or equal to the first threshold of the corresponding neighboring cell, the terminal device can perform cell selection or search for the first PLMN based on the first access technology information. This first threshold can be sent to the terminal device by the access network device, pre-configured in the terminal device, or determined by the terminal device based on neighboring cells (such as the radius of the neighboring cell's coverage area).

[0146] If the distance between the second location and the first location is greater than the first threshold of the corresponding neighboring cells, the terminal device can perform cell selection or search for the first PLMN without referring to the first access technology information. For example, the terminal device can select a PLMN according to the configured PLMN selection order, and after selecting a PLMN, try all access technologies under that PLMN in descending order of priority (5G, 4G, 3G, 2G), etc.

[0147] Taking the first access technology information included in the broadcast message as information about whether the first PLMN supports or does not support access technologies in the TA, the first value can be the second threshold corresponding to the TA. If the terminal device loses network access due to movement, or after being powered off and then powered on, if the distance between the terminal device's current second location and its first location is less than or equal to the second threshold corresponding to the TA, the terminal device can perform cell selection or search for the first PLMN based on the first access technology information. This second threshold can be sent to the terminal device by the access network equipment, pre-configured in the terminal device, or determined by the terminal device based on the TA (such as the radius of the TA's coverage area).

[0148] If the distance between the second location and the first location is greater than the second threshold of the corresponding TA, the terminal device can perform cell selection or search for the first PLMN without referring to the first access technology information. For example, the terminal device can select a PLMN according to the configured PLMN selection order, and after selecting a PLMN, try all access technologies under that PLMN in descending order of priority (5G, 4G, 3G, 2G), etc.

[0149] Figure 5 is a schematic diagram of the third embodiment of the network search method provided in this application. In the embodiment shown in Figure 5, taking AMF as the first device as an example, the method includes the following steps:

[0150] S501: The AMF sends information about whether the first PLMN supports or does not support a first access technology in the TA or RA, and the terminal device receives the information about whether the first PLMN supports or does not support a first access technology in the TA or RA.

[0151] As an example: After the terminal device initiates registration with the core network in the cell where it is camped, the core network device can send the first access technology information, including whether the first PLMN supports or does not support it in the TA or RA, to the terminal device through NAS messages, etc. The terminal device can obtain and store the first access technology information, including whether the first PLMN supports or does not support it in the neighboring cell or TA, etc., and at the same time record the first location of the terminal device when it obtains the first access technology information. The first location can be read from the GNSS module of the terminal device.

[0152] When a terminal device loses network access due to movement, or is powered on after being powered off, and needs to perform cell selection or PLMN search, the terminal device can execute step S502.

[0153] S502: The terminal device performs cell selection or searches for the first PLMN based on the current second location, the previous first location, and the first access technology information (whether the first PLMN supports or does not support the TA or RA).

[0154] Taking the first access technology information included in the NAS message as information about whether the first PLMN supports or does not support access technologies in the TA, the first value can be the second threshold corresponding to the TA. If a terminal device loses network access due to movement, or after being powered off and then powered on, if the distance between the terminal device's current second location and its first location is less than or equal to the second threshold corresponding to the TA, the terminal device can perform cell selection or search for the first PLMN based on the first access technology information. This second threshold can be sent to the terminal device by the AMF, pre-configured in the terminal device, or determined by the terminal device based on the TA (such as the radius of the TA's coverage area).

[0155] If the distance between the second location and the first location is greater than the second threshold of the corresponding TA, the terminal device can perform cell selection or search for the first PLMN without referring to the first access technology information. For example, the terminal device can select a PLMN according to the configured PLMN selection order, and after selecting a PLMN, try all access technologies under that PLMN in descending order of priority (5G, 4G, 3G, 2G), etc.

[0156] Taking the first access technology information included in the NAS message as information about whether the first PLMN supports or does not support access technologies in the RA, the first value can be the third threshold of the corresponding RA. If the terminal device loses network access due to movement, or after being powered off and then powered on, if the distance between the terminal device's current second location and its first location is less than or equal to the third threshold of the corresponding RA, the terminal device can perform cell selection or search for the first PLMN based on the first access technology information. This third threshold can be sent to the terminal device by the AMF, pre-configured in the terminal device, or determined by the terminal device based on the RA (such as the radius of the RA's coverage area).

[0157] If the distance between the second location and the first location is greater than the third threshold of the corresponding RA, the terminal device can perform cell selection or search for the first PLMN without referring to the first access technology information. For example, the terminal device can select a PLMN according to the configured PLMN selection order, and after selecting a PLMN, try all access technologies under that PLMN in descending order of priority (5G, 4G, 3G, 2G), etc.

[0158] Figure 6 is a schematic diagram of the fourth network search method provided in the embodiments of this application. In the embodiment shown in Figure 6, taking an access network device and an AMF as an example, the method includes the following steps:

[0159] S601: The access network device sends information about whether the first PLMN supports or does not support a first access technology in a neighboring cell, and correspondingly, the terminal device receives information about whether the first PLMN supports or does not support a first access technology in a neighboring cell.

[0160] As an example: an access network device can broadcast a message in its cell that includes information about whether the first PLMN supports or does not support the first access technology in neighboring cells. After a terminal device is camped in the cell of the access network device, it can monitor the broadcast message, obtain and store the information about whether the first PLMN supports or does not support the first access technology in neighboring cells included in the broadcast message, and at the same time record the first location of the terminal device when obtaining the first access technology information. The first location can be read from the GNSS module of the terminal device.

[0161] S602: The AMF sends information about whether the first PLMN supports or does not support a second access technology in the RA, and the terminal device receives the information about whether the first PLMN supports or does not support a second access technology in the RA.

[0162] As an example: After the terminal device registers with the core network in the cell where it is camped, the core network device can send information about the second access technology, including whether the first PLMN supports or does not support the RA, to the terminal device through NAS messages, etc. The terminal device can obtain and store the information about the second access technology, including whether the first PLMN supports or does not support the RA, carried in the NAS messages, and at the same time record the third location of the terminal device when it obtains the second access technology information. The third location information can be read from the GNSS module of the terminal device.

[0163] It should be understood that the order of steps S601 and S602 is not limited in the embodiments of this application. Step S601 can occur before step S602, after step S602, or simultaneously with step S602.

[0164] When a terminal device loses network access due to movement, or is powered on after being powered off, and needs to perform cell selection or PLMN search, the terminal device can execute step S603.

[0165] S603: The terminal device performs cell selection or searches for the first PLMN in the following order: first, based on the first access technology information (whether the first PLMN supports or does not support it in the neighboring cell); second, based on the second access technology information (whether the first PLMN supports or does not support it in the RA).

[0166] As an example: If a terminal device loses network access due to movement, or after being powered off and then powered on, and the distance between the terminal device's current second location and its first location is less than or equal to a first threshold of the corresponding neighboring cells, the terminal device can perform cell selection or search for the first PLMN based on the first access technology information (whether the first PLMN supports or does not support it in the neighboring cells). If a suitable cell is found, the terminal device can initiate access to that cell and stop performing cell selection or searching for the first PLMN. This first threshold can be sent to the terminal device by the access network device, pre-configured in the terminal device, or determined by the terminal device based on neighboring cells (such as the radius of the neighboring cell's coverage area).

[0167] If the terminal device fails to find a suitable cell to camp on based on the first access technology information (whether the first PLMN supports or does not support it in neighboring cells), or if the distance between the terminal device's current second location and its first location is greater than the first threshold of the corresponding neighboring cell, and the distance between the terminal device's current second location and its third location is less than or equal to the third threshold of the corresponding RA, the terminal device can perform cell selection or search for the first PLMN based on the second access technology information (whether the first PLMN supports or does not support it in the RA). If a suitable cell to camp on is found, the terminal device can initiate access to that cell and stop performing cell selection or searching for the first PLMN. This third threshold can be sent to the terminal device by the AMF, pre-configured in the terminal device, or determined by the terminal device based on the RA (such as the radius of the RA's coverage area).

[0168] If the terminal device fails to find a suitable cell to camp on based on the second access technology information supported or not supported by the first PLMN in the RA, or if the distance between the terminal device's current second location and third location is greater than the third threshold of the corresponding RA, the terminal device can search for other PLMNs. For example, it can select other PLMNs according to the configured PLMN selection order, and after selecting a PLMN, it can try all access technologies under that PLMN in descending order of priority (5G, 4G, 3G, 2G), etc.

[0169] Figure 7 is a fifth schematic diagram of the network search method provided in the embodiments of this application. In the embodiment shown in Figure 7, taking an access network device and an AMF as an example, the method includes the following steps:

[0170] S701: The access network device sends information about whether the first PLMN supports or does not support the first access technology in the TA, and correspondingly, the terminal device receives information about whether the first PLMN supports or does not support the first access technology in the TA.

[0171] As an example: an access network device can broadcast a message in its cell that includes information about whether the first PLMN supports or does not support the first access technology in the TA. After the terminal device is camped in the cell of the access network device, it can monitor the broadcast message, obtain and store the information about whether the first PLMN supports or does not support the TA in the broadcast message, and record the first location of the terminal device when it obtains the first access technology information. The first location can be read from the GNSS module of the terminal device.

[0172] S702: The AMF sends information on whether the first PLMN supports or does not support a second access technology in the RA. Accordingly, the terminal device receives information on whether the first PLMN supports or does not support a second access technology in the RA.

[0173] As an example: After the terminal device registers with the core network in the cell where it is camped, the core network device can send information about the second access technology, including whether the first PLMN supports or does not support it in the RA, to the terminal device through NAS messages, etc. The terminal device can obtain and store the information about the second access technology, including whether the first PLMN supports or does not support it in the RA, carried in the NAS messages, and at the same time record the third location of the terminal device when it obtains the second access technology information. The third location can be read from the GNSS module of the terminal device.

[0174] It should be understood that the order of steps S701 and S702 is not limited in the embodiments of this application. Step S701 may occur before step S702, after step S702, or simultaneously with step S702.

[0175] When a terminal device loses network access due to movement, or is powered on after being powered off, and needs to perform cell selection or PLMN search, the terminal device can execute step S703.

[0176] S703: The terminal device performs cell selection or searches for the first PLMN in the following order: first, based on the first access technology information (whether the first PLMN supports or does not support it in the TA), and second, based on the second access technology information (whether the first PLMN supports or does not support it in the RA).

[0177] As an example: If a terminal device loses network access due to movement, or after being powered off and then powered on, and the distance between the terminal device's current second location and its first location is less than or equal to the second threshold of the corresponding TA (Target Access Mode), the terminal device can perform cell selection or search for the first PLMN based on the first access technology information (whether the first PLMN supports or does not support the TA). If a suitable cell is found, the terminal device can initiate access to that cell and stop performing cell selection or searching for the first PLMN. This second threshold can be sent to the terminal device by the access network equipment, pre-configured in the terminal device, or determined by the terminal device based on the TA (such as the radius of the TA's coverage area).

[0178] If the terminal device fails to find a suitable cell to camp on based on the first access technology information (whether the first PLMN supports or does not support the first TA), or if the distance between the terminal device's current second location and its first location is greater than the second threshold of the corresponding TA, and the distance between the terminal device's current second location and its third location is less than or equal to the third threshold of the corresponding RA, the terminal device can perform cell selection or search for the first PLMN based on the second access technology information (whether the first PLMN supports or does not support the first RA). If a suitable cell is found, the terminal device can initiate access to that cell and stop performing cell selection or searching for the first PLMN. This third threshold can be sent to the terminal device by the AMF, pre-configured in the terminal device, or determined by the terminal device based on the RA (such as the radius of the RA's coverage area).

[0179] If the terminal device fails to find a suitable cell to camp on based on the second access technology information supported or not supported by the first PLMN in the RA, or if the distance between the terminal device's current second location and third location is greater than the third threshold of the corresponding RA, the terminal device can search for other PLMNs. For example, it can select other PLMNs according to the configured PLMN selection order, and after selecting a PLMN, it can try all access technologies under that PLMN in descending order of priority (5G, 4G, 3G, 2G), etc.

[0180] Figure 8 is a schematic diagram of the network search method provided in the embodiments of this application, specifically the sixth one. In the embodiment shown in Figure 8, taking an access network device as an example, the method includes the following steps:

[0181] S801: The access network device sends information about whether the first PLMN supports or does not support a first access technology in a neighboring cell, and correspondingly, the terminal device receives information about whether the first PLMN supports or does not support a first access technology in a neighboring cell.

[0182] As an example: an access network device can broadcast a message in its cell that includes information about whether the first PLMN supports or does not support the first access technology in neighboring cells. After a terminal device is camped in the cell of the access network device, it can monitor the broadcast message, obtain and store the information about whether the first PLMN supports or does not support the first access technology in neighboring cells included in the broadcast message, and at the same time record the first location of the terminal device when it obtains the first access technology information. The first location can be read from the GNSS module of the terminal device.

[0183] S802: The access network device sends information about whether the first PLMN supports or does not support the second access technology in the TA, and correspondingly, the terminal device receives information about whether the first PLMN supports or does not support the second access technology in the TA.

[0184] As an example: an access network device can broadcast a message in its cell that includes information about the second access technology, whether the first PLMN supports or does not support the TA. After the terminal device is camped in the cell of the access network device, it can monitor the broadcast message, obtain and store the information about the second access technology, whether the first PLMN supports or does not support the TA, and record the third location of the terminal device when it obtains the second access technology information. The third location can be read from the GNSS module of the terminal device.

[0185] It should be understood that the order of steps S801 and S802 is not limited in the embodiments of this application. Step S801 can occur before step S802, after step S802, or simultaneously with step S802.

[0186] If steps S801 and S802 occur simultaneously, the aforementioned first access technology information and second access technology information can be sent to the terminal device via two separate messages or via the same message; this application does not limit this. For example, the first access technology information (whether the first PLMN supports or does not support it in a neighboring cell) and the second access technology information (whether the first PLMN supports or does not support it in a TA) can be sent to the terminal device via the same broadcast message, meaning steps S801 and S802 can occur simultaneously. In this case, the first position the terminal device is in when obtaining the first access technology information is the same as the third position it is in when obtaining the second technology information.

[0187] When a terminal device loses network access due to movement, or is powered on after being powered off, and needs to perform cell selection or PLMN search, the terminal device can execute step S803.

[0188] S803: The terminal device performs cell selection or searches for the first PLMN in the following order: first, based on the first access technology information (whether the first PLMN supports or does not support it in the neighboring cell); second, based on the second access technology information (whether the first PLMN supports or does not support it in the TA).

[0189] As an example: If a terminal device loses network access due to movement, or after being powered off and then powered on, and the distance between the terminal device's current second location and its first location is less than or equal to a first threshold of the corresponding neighboring cells, the terminal device can perform cell selection or search for the first PLMN based on the first access technology information (whether the first PLMN supports or does not support it in the neighboring cells). If a suitable cell is found, the terminal device can initiate access to that cell and stop performing cell selection or searching for the first PLMN. This first threshold can be sent to the terminal device by the access network device, pre-configured in the terminal device, or determined by the terminal device based on neighboring cells (such as the radius of the neighboring cell's coverage area).

[0190] If the terminal device fails to find a suitable cell to camp on based on the first access technology information (whether the first PLMN supports or does not support it in neighboring cells), or if the distance between the terminal device's current second location and its first location is greater than the first threshold of the corresponding neighboring cell, and the distance between the terminal device's current second location and its third location is less than or equal to the second threshold of the corresponding TA, the terminal device can perform cell selection or search for the first PLMN based on the second access technology information (whether the first PLMN supports or does not support it in the TA). If a suitable cell to camp on is found, the terminal device can initiate access to that cell and stop performing cell selection or searching for the first PLMN. This second threshold can be sent to the terminal device by the access network device, pre-configured in the terminal device, or determined by the terminal device based on the TA (such as the radius of the TA's coverage area).

[0191] If the terminal device fails to find a suitable cell to camp on based on the second access technology information supported or not supported by the first PLMN in the TA, or if the distance between the terminal device's current second location and third location is greater than the second threshold of the corresponding TA, the terminal device can search for other PLMNs. For example, it can select other PLMNs according to the configured PLMN selection order, and after selecting a PLMN, it can try all access technologies under that PLMN in descending order of priority (5G, 4G, 3G, 2G), etc.

[0192] The communication device provided in the embodiments of this application is described below. Please refer to FIG9, which is a structural schematic diagram of the communication device in the embodiments of this application. The communication device may include units or modules corresponding to all or part of the steps in the above method embodiments, and can be used to execute the steps executed by the terminal device or the first device in the above embodiments. For details, please refer to the relevant descriptions in the above method embodiments.

[0193] As shown in Figure 9, the communication device 900 includes a processing unit 910 and an interface unit 920. The processing unit 910 can be a processor or a processing circuit, and the interface unit 920 can be a transceiver unit or an input / output interface. The communication device 900 can be used to implement the steps executed by the terminal device or the first device in the above embodiments.

[0194] When the communication device 900 is used to implement the steps performed by the terminal device in the above embodiments:

[0195] Interface unit 920 is used to receive information about whether the first PLMN supports or does not support the first access technology;

[0196] The processing unit 910 is used to perform cell selection or search for a first PLMN based on the current second location of the terminal device, the previous first location of the terminal device, and the first access technology information, wherein the first location is the location of the terminal device when receiving the first access technology information.

[0197] In one possible design, when the processing unit 910 performs cell selection or searches for the first PLMN based on the current second location of the terminal device, the previous first location of the terminal device, and the first access technology information, it is specifically used to perform cell selection or searches for the first PLMN based on the first access technology information if the distance between the second location and the first location is less than or equal to a first value.

[0198] In one possible design, the interface unit 920 is further configured to receive information on whether the first PLMN supports or does not support a second access technology, wherein the effective area of ​​the second access technology information is different from that of the first access technology information; the processing unit 910 is further configured to perform cell selection or search for the first PLMN based on the second location, the third location prior to the terminal device, and the second access technology information, wherein the third location is the location of the terminal device when receiving the second access technology information.

[0199] In one possible design, when the processing unit 910 performs cell selection or searches for the first PLMN based on the current second location of the terminal device, the previous third location of the terminal device, and the second access technology information, it is specifically used to perform cell selection or searches for the first PLMN based on the second access technology information if the distance between the second location and the third location is less than or equal to a second value.

[0200] In one possible design, the second access technology information comes from the access network equipment; or, the second access technology information comes from the core network equipment.

[0201] In one possible design, the first access technology information comes from the access network equipment; or, the first access technology information comes from the core network equipment.

[0202] In one possible design, the first value is determined based on a first region, which is: the neighboring cell, TA, or RA corresponding to the terminal device.

[0203] In one possible design, if the first access technology information is valid in a neighboring cell, the first value is the first threshold of the corresponding neighboring cell; if the first access technology information is valid in a TA, the first value is the second threshold of the corresponding TA; if the first access technology information is valid in an RA, the first value is the third threshold of the corresponding RA.

[0204] In one possible design, the interface unit 920 is also used to receive a first value from the access network device; or, to receive a first value from the core network device.

[0205] In one possible design, when the processing unit 910 performs cell selection or searches for the first PLMN based on the first access technology information, it is specifically used to prioritize searching for cells with access technologies supported by the first PLMN when performing cell selection; or, when searching for the first PLMN, prioritize searching for access technologies supported by the first PLMN based on the first access technology information.

[0206] In one possible design, the first PLMN is the registered PLMN of the terminal device and / or an equivalent PLMN of the registered PLMN.

[0207] When the communication device 900 is used to implement the steps performed by the first device in the above embodiments:

[0208] The processing unit 910 is used to obtain information on whether the first PLMN supports or does not support the first access technology. The first access technology information is used by the terminal device to perform cell selection or search for the first PLMN. The interface unit 920 is used to send the first access technology information.

[0209] In one possible design, the processing unit 910 is further configured to acquire information on whether the first PLMN supports or does not support a second access technology. The second access technology information is used by the terminal device to perform cell selection or search for the first PLMN. The effective areas of the second access technology information and the first access technology information are different. The interface unit 920 is further configured to send the second access technology information.

[0210] In one possible design, the first device includes access network equipment and / or core network equipment.

[0211] In one possible design, the interface unit 920 is also used to send a first value, which is used by the terminal device to determine whether to perform cell selection or search for the first PLMN based on the first access technology information, depending on whether the current second position is less than or equal to the previous first position. The first position is the position of the terminal device when receiving the first access technology information.

[0212] In one possible design, the interface unit 920 is also used to send a second value, which is used by the terminal device to determine whether to perform cell selection or search for the first PLMN based on the second access technology information, depending on whether the current second position is less than or equal to the previous third position. The third position is the position of the terminal device when receiving the second access technology information.

[0213] In one possible design, the first value is determined based on a first region, which is the neighboring cell, TA, or RA corresponding to the terminal device.

[0214] In one possible design, if the first access technology information is valid in a neighboring cell, the first value is a first threshold for the corresponding neighboring cell; if the first access technology information is valid in a TA, the first value is a second threshold for the corresponding TA; if the first access technology information is valid in an RA, the first value is a third threshold for the corresponding RA.

[0215] In one possible design, the first PLMN is the registered PLMN of the terminal device and / or an equivalent PLMN of the registered PLMN.

[0216] As shown in Figure 10, this application also provides a communication device 1000, including a processor 1010 and a communication interface 1020. The processor 1010 and the communication interface 1020 are coupled to each other. It is understood that the communication interface 1020 can be a transceiver, an input / output interface, an input interface, an output interface, an interface circuit, etc. Optionally, the communication device 1000 may further include a memory 1030 for storing instructions executed by the processor 1010, or storing input data required by the processor 1010 to execute instructions, or storing data generated after the processor 1010 executes instructions. The memory 1030 can be a physically independent unit, or it can be coupled to the processor 1010, or the processor 1010 may include the memory 1030.

[0217] When the communication device 1000 is used to implement the steps executed by the terminal device or the first device in the above embodiments, the processor 1010 can be used to implement the function of the processing unit 910, and the communication interface 1020 can be used to implement the function of the interface unit 920.

[0218] In this embodiment, the processor (e.g., processor 1010) can be one or more central processing units (CPUs). If the processor is a CPU, it can be a single-core CPU or a multi-core CPU. The processor can also be one or a combination of several of the following: CPU, general-purpose processor, application-specific integrated circuit (ASIC), digital signal processor (DSP), microprocessor unit (MPU), microcontroller unit (MCU), graphics processing unit (GPU), field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, artificial intelligence processor (AI processor), or neural processing unit (NPU). The processor can implement or execute the methods, steps, and logic block diagrams disclosed in this embodiment. The steps of the methods disclosed in this embodiment can be directly manifested as being executed by a hardware processor, or executed by a combination of hardware and software modules within the processor.

[0219] In this embodiment, the memory (e.g., memory 1030) may include, but is not limited to, cache, read-only memory (ROM), random access memory (RAM), synchronous dynamic random access memory (SDRAM), hard disk drive (HDD) or solid-state drive (SSD), erasable programmable read-only memory (EPROM), or compact disc read-only memory (CD-ROM), etc. Memory is any other medium capable of carrying or storing desired program code having an instruction or data structure form and accessible by a computer, but is not limited thereto. The memory in this embodiment may also be a circuit or any other device capable of implementing storage functions for storing computer programs or instructions, and / or data.

[0220] It is understood that the method steps in the embodiments of this application can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium well known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Additionally, the ASIC can reside in a network device or a terminal device. Alternatively, the processor and storage medium can exist as discrete components in the network device or terminal device.

[0221] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are performed entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user equipment, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions can be transferred from one network device, terminal, computer, server, or data center to another network device, terminal, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video optical disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both types of storage media.

[0222] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0223] In the embodiments of this application, the term "exemplary" is used to indicate that it is an example, illustration, or description. Any embodiment or design that is described as "exemplary" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Rather, the use of the term "exemplary" is intended to present the concept in a specific manner.

[0224] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply the order of execution; the execution order of each process should be determined by its function and internal logic.

Claims

1. A network search method, characterized by, The method comprises: receiving first access technology information supported or not supported by a first public land mobile network (PLMN); performing cell selection or searching for the first PLMN according to a current second location of the terminal device, a previous first location of the terminal device, and the first access technology information, the first location being the location of the terminal device when the first access technology information is received.

2. The method of claim 1, wherein, The performing cell selection or searching for the first PLMN according to the current second location of the terminal device, the previous first location of the terminal device, and the first access technology information comprises: if a distance between the second location and the first location is less than or equal to a first value, performing cell selection or searching for the first PLMN according to the first access technology information.

3. The method of claim 1 or 2, wherein, The method further comprises: receiving second access technology information supported or not supported by the first PLMN, the second access technology information being different from the first access technology information in terms of a valid area; performing the cell selection or searching for the first PLMN according to the second location, a previous third location of the terminal device, and the second access technology information, the third location being the location of the terminal device when the second access technology information is received.

4. The method of claim 3, wherein, The performing the cell selection or searching for the first PLMN according to the second location, the previous third location of the terminal device, and the second access technology information comprises: if a distance between the second location and the third location is less than or equal to a second value, performing the cell selection or searching for the first PLMN according to the second access technology information.

5. The method of claim 3 or 4, wherein, The second access technology information is from an access network device; or the second access technology information is from a core network device.

6. The method of any one of claims 1-5, wherein, The first access technology information is from an access network device; or the first access technology information is from a core network device.

7. The method of claim 2, wherein, The first value is determined based on a first area, the first area being: a neighbor cell, a tracking area (TA), or a registration area (RA) corresponding to the terminal device; 8. The method of claim 7, wherein, if the first access technology information is valid in the neighbor cell, the first value being a first threshold value corresponding to the neighbor cell; if the first access technology information is valid in the TA, the first value being a second threshold value corresponding to the TA; if the first access technology information is valid in the RA, the first value being a third threshold value corresponding to the RA.

9. The method of claim 2, 7, or 8, wherein, The method further comprises: receiving the first value from an access network device; or receiving the first value from a core network device.

10. The method of any one of claims 1-9, wherein, The performing cell selection or searching for the first PLMN according to the first access technology information comprises: when performing the cell selection, preferentially searching for a cell of an access technology supported by the first PLMN according to the first access technology information; or when searching for the first PLMN, preferentially searching for an access technology supported by the first PLMN according to the first access technology information.

11. The method of any one of claims 1-10, wherein, The first PLMN is a registration PLMN of the terminal device and / or an equivalent PLMN of the registration PLMN.

12. A network search method, characterized by, The method is applied to a first device and comprises: obtaining first access technology information supported or not supported by a first public land mobile network (PLMN), the first access technology information being used by a terminal device to perform cell selection or search for the first PLMN; sending the first access technology information.

13. The method of claim 12, wherein, The method further comprises: obtaining second access technology information supported or not supported by the first PLMN, the second access technology information being used by the terminal device to perform cell selection or search for the first PLMN, and the second access technology information being different from the first access technology information in terms of a valid area; sending the second access technology information.

14. The method of claim 13, wherein, The first device comprises an access network device and / or a core network device, and the sending of the second access technology information comprises: the access network device sending the second access technology information; or the core network device sending the second access technology information.

15. The method of any one of claims 12-14, wherein, The first device comprises an access network device and / or a core network device, and the sending of the first access technology information comprises: the access network device sending the first access technology information; or the core network device sending the first access technology information.

16. The method of any one of claims 12-15, wherein, The method further comprises: sending a first value, the first value being used by the terminal device to determine whether to perform cell selection or search for the first PLMN according to the first access technology information, according to whether a current second location is less than or equal to the first value compared with a previous first location, the first location being a location of the terminal device when the first access technology information is received.

17. The method of claim 16, wherein, The first value is determined based on a first area, the first area being: a neighboring cell, a tracking area (TA), or a registration area (RA) corresponding to the terminal device.

18. The method of claim 17, wherein, If the first access technology information is valid in the neighboring cell, the first value is a first threshold value corresponding to the neighboring cell. If the first access technology information is valid in the TA, the first value is a second threshold value corresponding to the TA. If the first access technology information is valid in the RA, the first value is a third threshold value corresponding to the RA.

19. The method of any one of claims 12-18, wherein, The first PLMN is a registration PLMN of the terminal device and / or an equivalent PLMN of the registration PLMN.

20. A communications device, characterized by comprise a module or unit for performing the method according to any one of claims 1-11; or comprise a module or unit for performing the method according to any one of claims 12-19.

21. A communications device, characterized by comprise a processor and an interface circuit for inputting and / or outputting signals, the processor being configured to implement the method according to any one of claims 1-11 by means of a logic circuit or by executing instructions; or implement the method according to any one of claims 12-19.

22. A computer program product, characterised in that, comprise a computer program or instructions, which, when executed by a processor, cause the method according to any one of claims 1-11 to be implemented; or cause the method according to any one of claims 12-19 to be implemented.

23. A chip system, characterized by The chip system comprises a processor configured to be coupled with a memory configured to store a computer program or instructions, which, when executed by the processor, implement the method of any one of claims 1-11, or implement the method of any one of claims 12-19.

24. A computer-readable storage medium, characterized in that, The storage medium stores a computer program or instructions, which, when executed by a processor, cause the method of any one of claims 1-11 to be implemented, or cause the method of any one of claims 12-19 to be implemented.

Images