Method, terminal device and network device for network selection

Abstract

A network selection method, a terminal device and a network device are provided, which are beneficial to selecting a suitable PLMN, thereby ensuring stable transmission of services of the terminal device. The method comprises: the terminal device performing PLMN selection according to priority ranking of public land mobile networks (PLMNs) and / or channel quality information of the PLMNs.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the field of communications, and in particular to a network selection method, a terminal device, and a network device. BACKGROUND

[0002] In a New Radio (NR) system, a terminal performs network selection (i.e., Public Land Mobile Network (PLMN) selection) based on a priority order of PLMNs in a Non-Access Stratum (NAS) layer. The priority order of the PLMNs is that a Registered PLMN (RPLMN) is higher than a Home PLMN (HPLMN) or a first EHPLMN.

[0003] However, for a terminal in an unstable network state (e.g., a roaming terminal), using the above network selection mechanism can cause the terminal to camp on an RPLMN or periodically return to the RPLMN, resulting in unstable data transmission of the terminal. Therefore, how to implement high-quality network selection is an urgent problem to be solved. SUMMARY

[0004] The present application provides a network selection method, a terminal device, and a network device, which are beneficial to selecting a suitable PLMN, thereby ensuring stable transmission of services of the terminal device.

[0005] In a first aspect, a network selection method is provided, which includes: performing, by a terminal device, Public Land Mobile Network (PLMN) selection according to a priority order of the PLMNs and / or channel quality information of the PLMNs.

[0006] In a second aspect, a network selection method is provided, which includes: sending, by a network device, indication information to a terminal device, the indication information being used to indicate a manner of PLMN selection of the terminal device.

[0007] In a third aspect, a terminal device is provided, which is configured to perform the method in the first aspect or any implementation manner thereof.

[0008] Specifically, the terminal device includes function modules configured to perform the method in the first aspect or any implementation manner thereof.

[0009] In a fourth aspect, a network device is provided, which is configured to perform the method in the second aspect or any implementation manner thereof.

[0010] Specifically, the network device includes function modules configured to perform the method in the second aspect or any implementation manner thereof.

[0011] In a fifth aspect, a terminal device is provided, comprising a processor and a memory. The memory is configured to store a computer program, and the processor is configured to invoke and run the computer program stored in the memory to execute the method in the first aspect or each implementation manner thereof.

[0012] In a sixth aspect, a network device is provided, comprising a processor and a memory. The memory is configured to store a computer program, and the processor is configured to invoke and run the computer program stored in the memory to execute the method in the second aspect or each implementation manner thereof.

[0013] In a seventh aspect, a chip is provided, configured to implement the method in any one of the first aspect to the second aspect or each implementation manner thereof.

[0014] In particular, the chip comprises a processor configured to invoke and run a computer program from a memory, so that a device installed with the chip executes the method in any one of the first aspect to the second aspect or each implementation manner thereof.

[0015] In an eighth aspect, a computer readable storage medium is provided, configured to store a computer program, which causes a computer to execute the method in any one of the first aspect to the second aspect or each implementation manner thereof.

[0016] In a ninth aspect, a computer program product is provided, comprising computer program instructions, which cause a computer to execute the method in any one of the first aspect to the second aspect or each implementation manner thereof.

[0017] In a tenth aspect, a computer program is provided, which, when running on a computer, causes the computer to execute the method in any one of the first aspect to the second aspect or each implementation manner thereof.

[0018] Through the above technical solution, the terminal device selects a PLMN according to the priority ranking of the public land mobile network (PLMN) and / or the channel quality information of the PLMN, which is conducive to selecting a suitable PLMN, thereby ensuring stable transmission of subsequent services of the terminal device. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a schematic diagram of a communication system architecture provided by an embodiment of the present application.

[0020] Figure 2 is a schematic flow chart of a network selection method according to an embodiment of the present application.

[0021] Figure 3is a schematic flowchart of another method of network selection provided by an embodiment of the present application.

[0022] Figure 4 is a schematic block diagram of a terminal device provided by an embodiment of the present application.

[0023] Figure 5 is a schematic block diagram of a network device provided by an embodiment of the present application.

[0024] Figure 6 is a schematic block diagram of a communication device provided by an embodiment of the present application.

[0025] Figure 7 is a schematic block diagram of a chip provided by an embodiment of the present application.

[0026] Figure 8 is a schematic block diagram of a communication system provided by an embodiment of the present application. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art without creative effort based on the embodiments in the present application are within the scope of protection of the present application.

[0028] The technical solutions of the embodiments of the present application can be applied to various communication systems, for example: Global System of Mobile communication (GSM) system, Code Division Multiple Access (CDMA) system, Wideband Code Division Multiple Access (WCDMA) system, General Packet Radio Service (GPRS), Long Term Evolution (LTE) system, Advanced long term evolution (LTE-A) system, New Radio (NR) system, evolved system of NR system, LTE-based access to unlicensed spectrum (LTE-U) system, NR-based access to unlicensed spectrum (NR-U) system, Non-Terrestrial Networks (NTN) system, Universal Mobile Telecommunication System (UMTS), Wireless Local Area Networks (WLAN), Wireless Fidelity (WiFi), 5th-Generation (5G) system or other communication systems, etc.

[0029] Generally, the traditional communication system supports a limited number of connections, which is easy to implement. However, with the development of communication technology, the mobile communication system will not only support the traditional communication, but also support, for example, Device to Device (D2D) communication, Machine to Machine (M2M) communication, Machine Type Communication (MTC), Vehicle to Vehicle (V2V) communication, or Vehicle to everything (V2X) communication, etc. The embodiments of the present application can also be applied to these communication systems.

[0030] Optionally, the communication system in the embodiments of the present application can be applied to a carrier aggregation (CA) scenario, can also be applied to a dual connectivity (DC) scenario, and can also be applied to a standalone (SA) network deployment scenario.

[0031] Optionally, the communication system in the embodiments of the present application can be applied to an unlicensed spectrum, which can also be regarded as a shared spectrum, or can be applied to a licensed spectrum, which can also be regarded as a non-shared spectrum.

[0032] The embodiments of the present application combine network devices and terminal devices, wherein the terminal device can also be referred to as a user equipment (UE), an access terminal, a user unit, a user station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent or a user device, etc.

[0033] The terminal device can be a station (STATION, ST) in a WLAN, can be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA) device, a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a next-generation communication system such as an NR network, or a terminal device in a future evolved public land mobile network (PLMN) network, etc.

[0034] In the embodiments of the present application, the terminal device can be deployed on land, including indoor or outdoor, handheld, wearable or vehicle-mounted; can also be deployed on the water surface (such as ships, etc.); can also be deployed in the air (such as airplanes, balloons and satellites, etc.).

[0035] In the embodiments of the present application, the terminal device can be a mobile phone, a tablet computer, a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal device in industrial control, a wireless terminal device in self driving, a wireless terminal device in remote medical treatment, a wireless terminal device in smart grid, a wireless terminal device in transportation safety, a wireless terminal device in smart city, or a wireless terminal device in smart home, etc.

[0036] By way of example and not limitation, in the embodiments of the present application, the terminal device can also be a wearable device. The wearable device can also be referred to as a wearable smart device, which is a general term for devices that are designed and developed by applying wearable technology to daily wear, such as glasses, gloves, watches, clothing, and shoes, etc. The wearable device is a portable device that is directly worn on the body or integrated into the clothes or accessories of the user. The wearable device is not only a hardware device, but also has powerful functions through software support and data interaction and cloud interaction. The general wearable smart device includes devices with full functions, large size, and the ability to realize complete or partial functions without relying on a smart phone, such as smart watches or smart glasses, etc., and devices that focus on a certain type of application function and need to be used in cooperation with other devices, such as smart phones, such as various smart wristbands and smart jewelry for monitoring vital signs, etc.

[0037] In the embodiments of the present application, the network device can be a device for communicating with the mobile device. The network device can be an access point (AP) in a WLAN, a base transceiver station (BTS) in GSM or CDMA, a base station (NodeB, NB) in WCDMA, an evolved Node B (eNB or eNodeB) in LTE, or a relay station or an access point, or a vehicle-mounted device, a wearable device, and a network device in an NR network, or a network device in a future evolved PLMN network, or a network device in an NTN network, etc.

[0038] By way of example and not limitation, in this embodiment, the network device may have mobility characteristics; for example, the network device may be a mobile device. Optionally, the network device may be a satellite or a balloon station. For example, the satellite may be a low Earth orbit (LEO) satellite, a medium Earth orbit (MEO) satellite, a geostationary earth orbit (GEO) satellite, a high elliptical orbit (HEO) satellite, etc. Optionally, the network device may also be a base station located on land, water, or other similar locations.

[0039] In this embodiment, the network device can provide services to a cell. The terminal device communicates with the network device through the transmission resources (e.g., frequency domain resources, or spectrum resources) used by the cell. The cell can be the cell corresponding to the network device (e.g., a base station). The cell can belong to a macro base station or to a base station corresponding to a small cell. The small cell can include: metro cell, micro cell, pico cell, femto cell, etc. These small cells have the characteristics of small coverage area and low transmission power, and are suitable for providing high-speed data transmission services.

[0040] For example, the communication system 100 used in the embodiments of this application is as follows: Figure 1 As shown. The communication system 100 may include a network device 110, which may be a device that communicates with a terminal device 120 (or a communication terminal, terminal). The network device 110 can provide communication coverage for a specific geographical area and can communicate with terminal devices located within that coverage area.

[0041] Figure 1 An exemplary embodiment shows a network device and two terminal devices. Optionally, the communication system 100 may include multiple network devices and each network device may include other numbers of terminal devices within its coverage area. This application embodiment does not limit this.

[0042] Optionally, the communication system 100 may also include other network entities such as a network controller and a mobility management entity, which is not limited in this embodiment.

[0043] It should be understood that devices with communication functions in the network / system of this application embodiment can be referred to as communication devices. Figure 1The communication system 100 shown is an example, and the communication device can include network devices 110 and terminal devices 120 having communication functions, and the network devices 110 and the terminal devices 120 can be the specific devices described above, which are not described again here. The communication device can also include other devices in the communication system 100, such as network controllers, mobile management entities, and other network entities, which are not limited in the embodiments of the present application.

[0044] It should be understood that the terms "system" and "network" are often used interchangeably herein. The term "and / or" herein is only a description of the associated relationship between the objects. For example, A and / or B can represent three cases: A alone, A and B together, and B alone. In addition, the character " / " generally represents an "or" relationship between the associated objects.

[0045] It should be understood that the "indication" mentioned in the embodiments of the present application can be direct indication, indirect indication, or can represent an associated relationship. For example, A indicates B, which can mean that B can be obtained by A; or A indirectly indicates B, for example, A indicates C, and B can be obtained by C; or A and B have an associated relationship.

[0046] In the description of the embodiments of the present application, the term "corresponding" can represent a direct or indirect relationship between the two, or can represent an associated relationship between the two, or can represent an indication and being indicated, configuration and being configured, etc.

[0047] In the embodiments of the present application, "predefined" can be realized by pre-saving corresponding codes, tables or other means for indicating related information in devices (such as terminal devices and network devices), and the specific implementation manner is not limited in the present application. For example, predefinition can refer to definition in a protocol.

[0048] In the embodiments of the present application, the "protocol" can refer to a standard protocol in the communication field, which can include LTE protocol, NR protocol and related protocols applied to future communication systems, and the present application is not limited to this.

[0049] In order to facilitate understanding of the technical solutions of the embodiments of the present application, the technical solutions of the present application are described in detail below through specific embodiments. The following related technologies can be combined with the technical solutions of the embodiments of the present application as optional schemes, which all belong to the protection scope of the embodiments of the present application. The embodiments of the present application include at least part of the following contents.

[0050] To meet the requirements of vertical industries in terms of latency, mobility, reliability, location accuracy, etc., the 5G system needs to enhance how to support vertical services in the access network. One possible scenario is to support the transmission of Internet of Things (IOT) services. The transmission characteristics of IoT services are usually as follows:

[0051] 1. IoT services are stationary.

[0052] 2. IoT services can be located in remote locations with limited coverage.

[0053] 3. IoT services require stable data connections as part of measurement and control networks.

[0054] 4. IoT devices can be permanently roaming, such as IoT devices whose modules are installed abroad, or intentionally to provide users with the best coverage in any situation.

[0055] When the UE enters the coverage area of the system, the UE performs a cell search procedure. Regardless of the state of the UE (e.g., connected, idle, inactive), the UE will perform a cell search when moving in the system to achieve mobility.

[0056] In related technologies, the Non-Access Stratum (NAS) of the UE performs network selection (i.e., PLMN selection) based on the priority ordering of the PLMN. Generally, the priority ordering of the PLMN is that the Registered PLMN (RPLMN) is higher than the Home PLMN (HPLMN) or the first EHPLMN.

[0057] In some scenarios, for UEs with unstable network states (such as roaming UEs), the above network selection method has some problems. This is because the current network selection mechanism / roaming steering mechanism makes the UE need to perform network selection according to the PLMN priority even if there are other conditions that are better (such as better channel quality conditions), so that the UE prefers to stay in the RPLMN network or needs to return to the RPLMN network periodically, resulting in poor connection quality of the UE, and ultimately causing problems such as unstable UE transmission. Therefore, how to achieve high-quality network selection is an urgent problem to be solved.

[0058] Figure 2 is a schematic flowchart of a network selection method 200 according to an embodiment of the present application, which can be performed by a terminal device in Figure 1 . As shown in FIG. 2, the method 200 can include the following steps.Figure 2 As shown, the method 200 at least includes the following parts:

[0059] S210, the terminal device performs PLMN selection according to a priority ranking of the public land mobile network (PLMN) and / or channel quality information of the PLMN.

[0060] In some embodiments of the present application, for a specific terminal, the terminal device performs PLMN selection according to a priority ranking of the PLMN and / or channel quality information of the PLMN.

[0061] In some other embodiments of the present application, for a specific service of the terminal device, the terminal device performs PLMN selection according to a priority ranking of the PLMN and / or channel quality information of the PLMN. Here, the terminal device can be any terminal.

[0062] In some other embodiments of the present application, for a specific service of the terminal device, the terminal device performs PLMN selection according to a priority ranking of the PLMN and / or channel quality information of the PLMN. Here, the terminal device can be any terminal.

[0063] In some embodiments, the specific terminal can be, for example, a specific type of terminal, such as a terminal supporting IOT service, or a specific mode of terminal, for example, the aforementioned permanently roaming terminal.

[0064] In some embodiments, the specific service can include, but is not limited to, at least one of the following: a service represented by a logical channel (LCH), a logical channel group (LCH group), a quality of service flow (QoS flow), a data radio bearer (DRB), a protocol data unit (PDU) session, and the like.

[0065] As an example, the specific service can include, for example, IOT service.

[0066] In some embodiments of the present application, the priority ranking of the PLMN can be a first PLMN priority ranking, which is different from a predefined second PLMN priority ranking.

[0067] For example, the second PLMN priority ranking can be RPLMN higher than HPLMN / the first EHPLMN.

[0068] For example, the second PLMN priority ranking can be an existing PLMN priority ranking.

[0069] In some embodiments, the first PLMN priority corresponds to a specific terminal, such as an IOT terminal.

[0070] In other words, for the specific terminal, the terminal device can perform PLMN selection according to the first PLMN priority.

[0071] In some embodiments, the first PLMN priority corresponds to a specific service.

[0072] In other words, for the specific service of any terminal, the terminal device can perform PLMN selection according to the first PLMN priority.

[0073] In some embodiments, the first PLMN priority corresponds to a specific service of a specific terminal, such as an IOT terminal, and the specific service can be the service in the foregoing examples.

[0074] For example, for the specific service of the IOT terminal, the terminal device can perform PLMN selection according to the first PLMN priority.

[0075] In some embodiments of the present application, the first PLMN priority can be indicated by the network device or can be predefined.

[0076] For example, the network device can indicate the first PLMN priority through dedicated signaling, such as Radio Resource Control (RRC) signaling or Non-Access Stratum (NAS) signaling, or can indicate the first PLMN priority through a System Information Block (SIB), and the present application is not limited thereto.

[0077] In some embodiments, the network device can determine which terminal devices to set the first PLMN priority in according to the device deployment of the UE, or the UE type, or the supported service type, or the UE location, or the channel quality of the network, so that these terminal devices can perform PLMN selection based on the specific PLMN priority, which is conducive to selecting into a suitable PLMN and ensuring the stability of subsequent service transmission.

[0078] For example, the first PLMN priority can be set in an IOT terminal or in a terminal supporting an IOT service.

[0079] In some embodiments, the network device can indicate the first PLMN priority ranking to the terminal device according to a device type of the UE, a device deployment of the UE, a location of the UE, or a type of the UE, or a type of service supported by the UE, or information about a channel quality of the network, and the like.

[0080] For example, the first PLMN priority ranking can be indicated to an IOT terminal or a terminal supporting IOT service.

[0081] In some embodiments, the network device can indicate the first PLMN priority ranking to only a specific terminal, and other terminals can use a predefined second PLMN priority ranking for PLMN selection.

[0082] In some embodiments of the present application, the terminal device can perform PLMN selection according to the first PLMN priority ranking in a case that the terminal device is a specific terminal.

[0083] In some embodiments of the present application, the terminal device can perform PLMN selection according to the first PLMN priority ranking in a case that a service to be transmitted by the terminal device is a specific service.

[0084] In some embodiments of the present application, the terminal device can perform PLMN selection according to the first PLMN priority ranking in a case that the terminal device is a specific terminal and a service to be transmitted by the terminal device is a specific service.

[0085] That is, the terminal device can perform PLMN selection according to the first PLMN priority ranking without being based on the indication of the network device.

[0086] In some embodiments of the present application, the terminal device can perform PLMN selection according to the first PLMN priority ranking based on the indication of the network device.

[0087] For example, the terminal device can receive the first indication information sent by the network device, and perform PLMN selection according to the first PLMN priority ranking if the first indication information indicates that PLMN selection is based on the first PLMN priority ranking.

[0088] In some embodiments, the first indication information corresponds to a specific terminal, or the first indication information corresponds to a specific service, or the first indication information corresponds to a specific service of a specific terminal. The specific implementation of the specific terminal and the specific service is described above, and is not repeated here for brevity.

[0089] That is, the network device can indicate that PLMN selection is based on the first PLMN priority ranking for a specific terminal and / or a specific service.

[0090] In some embodiments, the first indication information is transmitted through system information or dedicated signaling. For example, the dedicated signaling can be NAS signaling or RRC signaling, and the present application is not limited thereto.

[0091] In some embodiments, the network device can indicate whether a specific terminal and / or a specific service performs PLMN selection based on the first PLMN priority ranking. Optionally, the first PLMN priority ranking can be further indicated, or the first PLMN priority ranking is predefined.

[0092] For example, the network device can indicate that a specific terminal and / or a specific service performs PLMN selection based on the first PLMN priority ranking, and other terminals and / or services perform PLMN selection based on a second PLMN priority ranking.

[0093] In some embodiments of the present application, the access layer (Access Stratum, AS) of the terminal device can search and / or measure the PLMN to obtain the search result of the PLMN and / or the channel quality information of the PLMN.

[0094] In some embodiments, the channel quality information of the PLMN can include, but is not limited to, at least one of the following:

[0095] Reference Signal Receiving Power (RSRP), Reference Signal Receiving Quality (RSRQ), Signal to Interference plus Noise Ratio (SINR), Channel Quantity Indicator (CQI), and Signal to Noise Ratio (SNR).

[0096] Further, the AS of the terminal device can report first information to the NAS of the terminal device, and the first information can include part or all of the search result of the PLMN and / or the channel quality information of the PLMN.

[0097] Optionally, the search result of the PLMN can be a PLMN identifier.

[0098] In some embodiments, the first information can include the PLMN whose channel quality satisfies the first condition and / or the channel quality information of the PLMN.

[0099] Optionally, the channel quality satisfying the first condition can include at least one of the following:

[0100] the channel quality satisfies the high quality condition, the channel quality does not satisfy the high quality condition, the channel quality is indicated as high quality.

[0101] As an example, the first information can comprise at least one of:

[0102] a. a PLMN whose channel quality satisfies the high quality condition;

[0103] b. a PLMN whose channel quality does not satisfy the high quality condition;

[0104] c. channel quality information of the PLMN;

[0105] d. a threshold corresponding to the high quality condition.

[0106] Optionally, for the PLMN in information a, one high quality indication can be configured to indicate that the PLMN has high quality, in this case, the channel quality information of the PLMN can not be reported. That is, the channel quality information of the PLMN in information a can not be included in information c.

[0107] In some embodiments, the PLMN whose channel quality satisfies the high quality condition can comprise at least one of:

[0108] a PLMN whose channel quality is greater than -110dbm;

[0109] a PLMN whose channel quality is greater than a third channel quality threshold.

[0110] In some embodiments, the third channel quality threshold can be greater than -110dbm.

[0111] In some embodiments, the PLMN whose channel quality does not satisfy the high quality condition can comprise at least one of:

[0112] a PLMN whose channel quality is less than -110dbm;

[0113] a PLMN whose channel quality is less than a third channel quality threshold;

[0114] a PLMN whose channel quality is greater than -110dbm and less than or equal to a third channel quality threshold.

[0115] In some embodiments, the third channel quality threshold corresponds to a specific terminal or a specific service.

[0116] That is, for a specific terminal, or a terminal supporting a specific service, or a specific service of the terminal, the reporting of the first information can be performed according to the third channel quality threshold.

[0117] In some embodiments, the information c can include the channel quality information of the PLMNs in the information b, or can also include the channel quality information of all the PLMNs searched by the terminal device, or can also only include the channel quality information of the PLMNs in the information a.

[0118] In some embodiments, the information d can include the third channel quality threshold, or -110dbm.

[0119] In some embodiments of the present application, the channel quality being indicated as high quality can be understood as the channel quality being higher than or equal to the third channel quality threshold, or higher than or equal to -110dbm.

[0120] Optionally, in some embodiments, the AS of the terminal device can send the first information to the NAS of the terminal device based on the indication of the NAS layer of the terminal device, for example, in the case of receiving the fourth indication information sent by the NAS of the terminal device.

[0121] Optionally, in some embodiments, the AS of the terminal device can send the channel quality information of a specific PLMN and / or the third channel quality threshold to the NAS of the terminal device based on the indication of the NAS layer of the terminal device, for example, in the case of receiving the third indication information sent by the NAS of the terminal device, wherein the third indication information is used to indicate the reporting of the channel quality information of the specific PLMN and / or the third channel quality threshold.

[0122] That is, the NAS of the terminal device can indicate to the AS of the terminal device which channel quality information of the PLMN needs to be reported.

[0123] In some embodiments, the specific PLMN includes at least one of the following cases:

[0124] All the PLMNs searched by the terminal device;

[0125] The PLMNs in the all PLMNs whose channel quality is higher than the third channel quality threshold;

[0126] The PLMNs in all the PLMNs whose channel quality is higher than -110dbm.

[0127] In some embodiments, the first information can only include the aforementioned information a, that is, the terminal device can only report the PLMNs with high quality indication, and relative to the consideration of the channel quality, location, deployment, etc. of the terminal device, further, the NAS of the terminal device is beneficial to select to the appropriate PLMN when selecting the PLMN according to the first information.

[0128] In some embodiments of the present application, the NAS of the terminal device can perform PLMN selection according to the first information reported by the AS of the terminal device and the first PLMN priority ranking.

[0129] For example, the PLMN with the highest priority among the PLMNs reported by the AS of the terminal device can be determined as the target PLMN.

[0130] For another example, the PLMN with a priority higher than the first priority threshold among the PLMNs reported by the AS of the terminal device can be determined as the target PLMN.

[0131] Optionally, if there are multiple PLMNs with the highest priority or a priority higher than the first priority threshold among the reported PLMNs, the terminal device can further select in combination with the channel quality of the multiple PLMNs, for example, select the PLMN with the best channel quality among the multiple PLMNs, or the PLMN with a channel quality higher than a specific channel threshold as the target PLMN.

[0132] In some embodiments, the first priority threshold is predefined or indicated by the network device.

[0133] In some embodiments, the first priority threshold is indicated by system information or dedicated signaling, for example, indicated by NAS signaling or RRC signaling.

[0134] In summary, for a specific terminal or a specific service, the terminal device performs PLMN selection based on a specific PLMN priority ranking (i.e., the first PLMN priority ranking), which is equivalent to considering the device deployment situation, location, and other information of the terminal device, which is beneficial for the terminal device to select a suitable PLMN and further ensure stable transmission of subsequent services.

[0135] In yet some embodiments of the present application, the terminal device performs PLMN selection according to the priority ranking of the PLMNs and the channel quality information of the PLMNs.

[0136] Optionally, the priority ranking of the PLMNs can be the first PLMN priority ranking or the second PLMN priority ranking, which is not limited in the present application.

[0137] In some embodiments of the present application, the terminal device performs PLMN selection according to the priority ranking of the PLMNs and the channel quality information of the PLMNs based on the indication of the network device.

[0138] For example, the terminal device can receive second indication information sent by the network device, the second indication information indicating that the terminal device performs PLMN selection according to the priority ranking of the PLMNs and the channel quality information of the PLMNs.

[0139] In some embodiments, the second indication information corresponds to a specific terminal, or the second indication information corresponds to a specific service, or the second indication information corresponds to a specific service of a specific terminal. The specific implementation of the specific terminal and the specific service is described above, and is not repeated here for brevity.

[0140] In some embodiments, the second indication information is sent through system information or dedicated signaling. For example, the dedicated signaling can be NAS signaling or RRC signaling, and the present application is not limited thereto.

[0141] In some embodiments, for a specific terminal, the terminal device can perform PLMN selection according to the priority ranking of the PLMNs and the channel quality information of the PLMNs.

[0142] That is, in the case of a specific terminal, the terminal device performs PLMN selection according to the priority ranking of the PLMNs and the channel quality information of the PLMNs.

[0143] In other embodiments, for a specific service of the terminal device, the terminal device can perform PLMN selection according to the priority ranking of the PLMNs and the channel quality information of the PLMNs.

[0144] That is, in the case of a specific service to be transmitted by the terminal device, the terminal device performs PLMN selection according to the priority ranking of the PLMNs and the channel quality information of the PLMNs.

[0145] In yet other embodiments, for a specific service of a specific terminal, the terminal device can perform PLMN selection according to the priority ranking of the PLMNs and the channel quality information of the PLMNs.

[0146] That is, in the case of a specific terminal and a specific service to be transmitted by the terminal device, the terminal device performs PLMN selection according to the priority ranking of the PLMNs and the channel quality information of the PLMNs. For example, for IOT services corresponding to IOT terminals, the terminal device can perform PLMN selection according to the priority ranking of the PLMNs and the channel quality information of the PLMNs.

[0147] In summary, the PLMN selection can be predefined for a specific terminal, or a specific service, or a specific service of a specific terminal according to the PLMN priority ranking and the channel quality information of the PLMN, in which case, the indication of the network device can not be required, for example, the PLMN selection manner can be set in the terminal device.

[0148] In some embodiments, the network device can indicate whether the specific terminal and / or the specific service is based on the PLMN priority ranking and the channel quality information of the PLMN for the PLMN selection.

[0149] For example, the network device can indicate that the specific terminal and / or the specific service is based on the PLMN priority ranking and the channel quality information of the PLMN for the PLMN selection, wherein the PLMN priority ranking can be the first PLMN priority ranking or the second PLMN priority ranking, and other terminals and / or services are based on the second PLMN priority ranking for the PLMN selection.

[0150] In some embodiments, the network device can determine, according to the device deployment of the UE, the UE location or the channel quality of the network, etc., in which terminal devices the manner of the PLMN selection according to the PLMN priority ranking and the channel quality of the PLMN is set, so that these terminal devices can be based on the PLMN priority ranking and the channel quality of the PLMN for the PLMN selection, which is conducive to selecting into a suitable PLMN and ensuring the stability of subsequent service transmission.

[0151] In other embodiments, the network device can indicate to the terminal device, according to the device type of the terminal, the device deployment of the UE, the UE location or the channel quality of the network, etc., that the PLMN selection is based on the PLMN priority ranking and the channel quality of the PLMN.

[0152] In some embodiments, the network device can only indicate to the specific terminal that the PLMN selection is based on the PLMN priority ranking and the channel quality of the PLMN, and other terminals can use the predefined second PLMN priority ranking for the PLMN selection.

[0153] In some embodiments of the present application, the AS of the terminal device can search and / or measure the PLMN to obtain the search result of the PLMN and / or the channel quality information of the PLMN.

[0154] In some embodiments, the channel quality information of the PLMN can include at least one of the following:

[0155] RSRP, RSRQ, SINR, CQI, SNR.

[0156] Further, the AS of the terminal device can report the first information to the NAS of the terminal device, and the first information can include part or all of the search result of the PLMN and / or the channel quality information of the PLMN.

[0157] In some embodiments, the first information can include the PLMN whose channel quality satisfies the first condition and / or the channel quality information of the PLMN.

[0158] Optionally, the channel quality satisfying the first condition can include at least one of the following:

[0159] The channel quality satisfies a high-quality condition, the channel quality does not satisfy the high-quality condition, and the channel quality is indicated as high quality.

[0160] As an example, the first information can include at least one of the following:

[0161] a. the PLMN whose channel quality satisfies the high-quality condition;

[0162] b. the PLMN whose channel quality does not satisfy the high-quality condition;

[0163] c. the channel quality information of the PLMN;

[0164] d. the threshold corresponding to the high-quality condition.

[0165] Optionally, for the PLMN in information a, one high-quality indication can be configured to indicate that the PLMN has high quality, and in this case, the channel quality information of the PLMN can not be reported. That is, the channel quality information of the PLMN in information a can not be included in information c.

[0166] In some embodiments, the PLMN whose channel quality satisfies the high-quality condition can include at least one of the following:

[0167] The PLMN whose channel quality is greater than -110dbm;

[0168] The PLMN whose channel quality is greater than a third channel quality threshold.

[0169] In some embodiments, the third channel quality threshold can be greater than -110dbm.

[0170] In some embodiments, the PLMN whose channel quality does not satisfy the high-quality condition can include at least one of the following:

[0171] The PLMN whose channel quality is less than -110dbm;

[0172] The PLMN whose channel quality is less than a third channel quality threshold.

[0173] the PLMNs whose channel quality is greater than -110dbm and less than or equal to the third channel quality threshold.

[0174] In some embodiments, the third channel quality threshold corresponds to a specific terminal or a specific service.

[0175] That is, for a specific terminal or a specific service of the terminal, the reporting of the first information can be based on the third channel quality threshold.

[0176] In some embodiments, the information c can include the channel quality information of the PLMNs in the information b, or can include the channel quality information of all the PLMNs searched by the terminal device, or can only include the channel quality information of the PLMNs in the information a.

[0177] In some embodiments, the information d can include the third channel quality threshold or -110dbm.

[0178] Optionally, in some embodiments, the AS of the terminal device can send the channel quality information of a specific PLMN and / or the third channel quality threshold to the NAS of the terminal device based on the indication of the NAS layer of the terminal device, for example, in the case of receiving the third indication information sent by the NAS of the terminal device, wherein the third indication information is used to indicate the reporting of the channel quality information of the specific PLMN and / or the third channel quality threshold.

[0179] That is, the NAS of the terminal device can indicate to the AS of the terminal device which channel quality information of the PLMN needs to be reported.

[0180] In some embodiments, the specific PLMN includes at least one of the following cases:

[0181] all the PLMNs searched by the terminal device;

[0182] the PLMNs whose channel quality is higher than the third channel quality threshold among the all the PLMNs;

[0183] the PLMNs whose channel quality is higher than -110dbm among the all the PLMNs.

[0184] In some embodiments, the first information can only include the aforementioned information a, that is, the terminal device can only report the PLMNs with high quality indication, and further, the NAS of the terminal device is beneficial to select a suitable PLMN when selecting the PLMNs based on the first information, considering the channel quality, location, deployment, etc. of the terminal device.

[0185] In some embodiments of the present application, the terminal device performs PLMN selection according to the first information in combination with PLMN priority ranking and channel quality information of the PLMN.

[0186] Option 1:

[0187] The terminal device performs PLMN selection according to the first information in combination with PLMN priority ranking and channel quality information of the PLMN, including:

[0188] determining a first PLMN set according to the PLMN priority ranking and the search result of the PLMN;

[0189] determining a target PLMN according to channel quality information of the PLMN in the first PLMN set.

[0190] When performing PLMN selection based on PLMN priority ranking and channel quality information of the PLMN, a first PLMN set can be determined according to the PLMN priority ranking first, and a target PLMN can be determined in combination with channel quality information of the PLMN.

[0191] It should be understood that in the embodiments of the present application, when performing PLMN selection in combination with channel quality information of the PLMN, the channel quality information of the PLMN can be a measurement result of the PLMN, such as RSRP, or it can also be channel quality information obtained by adjusting the measurement result of the PLMN, for example, the measurement result of the PLMN can be added with a specific adjustment amount to determine the channel quality information of the PLMN, and the specific adjustment amount can be determined according to the priority ranking of the PLMN. For example, if the PLMN is of high priority, the corresponding adjustment amount can be a positive adjustment amount, or if the PLMN is of low priority, the corresponding adjustment amount can be 0 or a negative adjustment amount.

[0192] In some embodiments, the first PLMN set includes at least one of the following PLMNs:

[0193] a PLMN with the highest priority in the search result of the PLMN in the PLMN priority ranking;

[0194] a PLMN with a priority higher than a second priority threshold in the search result of the PLMN in the PLMN priority ranking.

[0195] That is, when determining the first PLMN set according to the PLMN priority ranking, the PLMN with the highest priority can be selected, or the PLMN with a priority higher than a second priority threshold can also be selected to constitute the first PLMN set.

[0196] In some embodiments, the second priority threshold is indicated by a network device or predefined.

[0197] In some embodiments, the second priority threshold is indicated by system information or dedicated signaling, for example, by NAS signaling or RRC signaling.

[0198] In some embodiments, the second priority threshold corresponds to a specific terminal or a specific service.

[0199] In some embodiments, the target PLMN includes at least one of:

[0200] a PLMN with the highest channel quality in the first PLMN set;

[0201] a PLMN with channel quality higher than a first channel quality threshold in the first PLMN set;

[0202] a PLMN with channel quality indicated as high quality in the first PLMN set;

[0203] a PLMN with channel quality satisfying a high quality condition in the channel quality information of the PLMN;

[0204] a PLMN with channel quality not satisfying a high quality condition in the channel quality information of the PLMN.

[0205] In an implementation, the terminal device can sort the PLMNs in the search result of the PLMN in order of priority from high to low, select a PLMN with priority within a certain range (for example, higher than the second priority threshold), if the number of PLMNs satisfying the condition is one, the terminal device can select the one PLMN as the target PLMN, or if the number of PLMNs satisfying the condition is multiple, the terminal device can further select a PLMN from the multiple PLMNs according to the channel quality of the multiple PLMNs, for example, sort the channel quality of the multiple PLMNs in order from high to low, in an implementation, the terminal device can select a PLMN with the highest channel quality.

[0206] For example, if the channel quality of the PLMN with the highest priority in the first PLMN set is X1, the corresponding adjustment amount is delta1, the target channel quality of the PLMN is X1+delta1, the channel quality of the PLMN with the second highest priority is X2, the corresponding adjustment amount is delta2, the target channel quality of the PLMN is X2+delta2, if X1+delta1 is greater than X2+delta2, the terminal device can select the PLMN with the highest priority as the target PLMN, otherwise, the terminal device can select the PLMN with the second highest priority as the target PLMN.

[0207] In some embodiments, the channel quality being indicated as high quality can include the channel quality being higher than -110dbm, or the channel quality being higher than a third channel quality threshold.

[0208] For the PLMNs with the channel quality being higher than -110dbm, or the channel quality being higher than the third channel quality threshold, a high quality indication can be configured, and when performing the PLMN selection, the PLMN with the high quality indication can be preferred.

[0209] In some embodiments, the channel quality satisfying the high quality condition can include the channel quality being greater than -110dbm, or the channel quality being higher than the third channel quality threshold.

[0210] Optionally, in some embodiments, the first channel quality threshold is indicated by the network device or predefined. Optionally, the network device can indicate the first channel quality threshold when indicating the terminal device to perform the PLMN selection according to the priority of the PLMN and the channel quality information of the PLMN. That is, the first channel quality threshold and the second indication information are indicated by the same message.

[0211] Optionally, in some embodiments, the first channel quality threshold is indicated by system information or dedicated signaling, such as NAS signaling or RRC signaling, and the application is not limited thereto.

[0212] Optionally, in some embodiments, the first channel quality threshold is indicated by system information or dedicated signaling, such as NAS signaling or RRC signaling, and the application is not limited thereto.

[0213] The terminal device performs the PLMN selection according to the first information, in combination with the priority ranking of the PLMN and the channel quality information of the PLMN, including:

[0214] According to the channel quality information of the PLMN reported by the AS of the terminal device, a second PLMN set is determined;

[0215] According to the priority ranking of the PLMN, a target PLMN is determined in the second PLMN set.

[0216] When performing the PLMN selection based on the priority ranking of the PLMN and the channel quality information of the PLMN, the second PLMN set can be first determined according to the channel quality information of the PLMN, and then the target PLMN is determined in combination with the priority ranking of the PLMN.

[0217] In some embodiments, the second PLMN set includes at least one of the following PLMNs:

[0218] The PLMN with the highest channel quality in the channel quality information of the PLMN;

[0219] The PLMN with the channel quality higher than the second channel quality threshold in the channel quality information of the PLMN;

[0220] the PLMN whose channel quality is indicated as high quality in the channel quality information reported by the AS of the terminal device;

[0221] the PLMN whose channel quality satisfies the high quality condition in the channel quality information of the PLMN;

[0222] the PLMN whose channel quality does not satisfy the high quality condition in the channel quality information of the PLMN.

[0223] In the specific description of the PLMN whose channel quality is indicated as high quality and the PLMN whose channel quality satisfies the high quality condition, reference can be made to the related description in the manner 1, which will not be repeated here.

[0224] In an implementation manner, the terminal device can sort the PLMNs in the search result of the PLMN in descending order of channel quality, select the PLMNs whose channel quality is within a certain range (for example, higher than the second channel quality threshold), if the number of the PLMNs satisfying the condition is one, the terminal device can select the one PLMN as the target PLMN, or if the number of the PLMNs satisfying the condition is multiple, the terminal device can further select the PLMN according to the priority of the multiple PLMNs, for example, sort the priority of the multiple PLMNs in descending order, and in an implementation manner, the terminal device can select the PLMN with the highest priority.

[0225] In some embodiments, the second channel quality threshold is indicated by the network device or predefined.

[0226] In some embodiments, the second channel quality threshold is indicated by system information or dedicated signaling.

[0227] In some embodiments, the second channel quality threshold corresponds to a specific terminal or a specific service.

[0228] In some embodiments, the target PLMN includes at least one of the following:

[0229] the PLMN with the highest priority in the PLMN priority ranking in the second PLMN set;

[0230] the PLMN with a priority higher than the third priority threshold in the PLMN priority ranking in the second PLMN set.

[0231] In some embodiments, the third priority threshold is indicated by the network device or predefined.

[0232] In some embodiments, the third priority threshold is indicated by system information or dedicated signaling.

[0233] In some embodiments, the third channel quality threshold corresponds to a specific terminal or a specific service.

[0234] Optionally, in some embodiments, the first channel quality threshold, the second channel quality threshold and the third channel quality threshold can be the same or different.

[0235] Optionally, in some embodiments, the first priority threshold, the second priority threshold and the third priority threshold can be the same or different.

[0236] In summary, for a specific terminal or a specific service, the terminal device performs PLMN selection based on the PLMN priority ranking and the channel quality information of the PLMN, which is equivalent to considering the device deployment situation, location, channel quality and other information of the terminal device, and is conducive to the terminal device selecting a suitable PLMN, thereby ensuring stable transmission of services.

[0237] In the following, specific implementation processes of the terminal device performing PLMN selection are described in combination with specific embodiments.

[0238] Embodiment 1

[0239] Step 1: The AS of the terminal device searches and / or measures the PLMN to obtain the search result of the PLMN and / or the channel quality information of the PLMN.

[0240] Optionally, the terminal device can also obtain the system information of the cell.

[0241] Optionally, the system information can include first indication information, which is used to instruct the terminal device to perform PLMN selection according to the first PLMN priority ranking.

[0242] Optionally, the first indication information corresponds to a specific terminal, such as an IOT terminal, or a specific service, such as an IOT service.

[0243] Optionally, the AS of the terminal device can instruct the NAS of the terminal device to perform PLMN selection according to the first PLMN priority ranking.

[0244] Optionally, the first PLMN priority ranking can also correspond to a specific terminal or a specific service, in which case, it can not be necessary to perform PLMN selection according to the first PLMN priority ranking based on the indication of the network device.

[0245] Optionally, the first PLMN priority ranking can be indicated by the network device, for example, indicated by the network device through system information or dedicated signaling, or predefined, for example, agreed by the protocol, or set in the terminal device.

[0246] It should be understood that the terminal device performs PLMN selection based on the first PLMN priority ranking, which can be based on the indication of the network device, or can also be determined according to the type of the terminal device or the type of the service to be transmitted.

[0247] Step 2: The AS layer of the terminal device reports the first information to the NAS layer of the terminal device.

[0248] Optionally, the first information can include at least one of the following:

[0249] a. A PLMN with a channel quality higher than -110dbm, which corresponds to a high-quality indication;

[0250] b. A PLMN with a channel quality lower than -110dbm;

[0251] c. Channel quality information corresponding to the PLMN.

[0252] Optionally, the channel quality information corresponding to the PLMN in information c can be the channel quality corresponding to the PLMN in channel b, and the NAS of the terminal device can not necessarily report the channel quality of the PLMN with a high-quality indication.

[0253] Step 3: The NAS of the terminal device performs PLMN selection according to the first PLMN priority ranking.

[0254] For example, the highest priority PLMN among the reported PLMNs is selected as the target PLMN.

[0255] For another example, the PLMN with the highest priority and a high-quality indication among the reported PLMNs is selected as the target PLMN.

[0256] Step 4: The AS of the terminal device acquires the target PLMN selected by the NAS of the terminal device, and further performs cell selection or camping, etc.

[0257] In summary, for a specific terminal or a specific service, the terminal device performs PLMN selection based on a specific PLMN priority ranking (i.e., the first PLMN priority ranking), which takes into account the device deployment, location, channel quality, etc. of the terminal device, and is beneficial for the terminal device to select a suitable PLMN and further ensure continuous transmission of the service.

[0258] Embodiment 2

[0259] Step 1: The AS of the terminal device searches and / or measures the PLMN, and acquires the search result of the PLMN and / or the channel quality information of the PLMN.

[0260] Optionally, the terminal device can also acquire the system information of the cell.

[0261] Optionally, the system information can include second indication information, which is used to indicate that the terminal device performs PLMN selection according to the PLMN priority ranking and the channel quality information of the PLMN.

[0262] Optionally, the second indication information corresponds to a specific terminal, such as an IOT terminal, or a specific service, such as an IOT service.

[0263] Optionally, the above-mentioned PLMN selection manner corresponds to a specific terminal or a specific service, in which case, the terminal device can not necessarily perform PLMN selection according to the PLMN priority ranking and the channel quality information of the PLMN based on the indication of the network device.

[0264] That is, the terminal device can perform PLMN selection based on the PLMN priority ranking and the channel quality information of the PLMN based on the indication of the network device, or can be determined according to the type of the terminal device or the type of the service to be transmitted.

[0265] Optionally, the AS of the terminal device can instruct the NAS of the terminal device to perform PLMN selection according to the PLMN priority ranking and the channel quality information of the PLMN.

[0266] Step 2: The AS of the terminal device reports first information to the NAS of the terminal device.

[0267] Optionally, the first information can include at least one of the following:

[0268] a. The PLMN with channel quality higher than -110dbm, which corresponds to a high-quality indication;

[0269] b. The PLMN with channel quality lower than -110dbm;

[0270] c. The channel quality information corresponding to the PLMN.

[0271] Optionally, the channel quality information corresponding to the PLMN in information c can include the channel quality corresponding to the PLMN in channel b, and the NAS can not necessarily report the channel quality of the PLMN with a high-quality indication.

[0272] Optionally, the channel quality information corresponding to the PLMN in information c can include the channel quality corresponding to all the PLMNs searched by the terminal device.

[0273] Optionally, the AS of the terminal device can report the channel quality information corresponding to all the PLMNs based on the indication of the NAS of the terminal device.

[0274] That is, the NAS of the terminal device can indicate to the AS of the terminal device which channel quality information of which PLMN needs to be reported.

[0275] Step 3: The NAS of the terminal device performs PLMN selection according to the PLMN priority ranking and the channel quality information of the PLMNs.

[0276] Method 1: The NAS of the terminal device first performs PLMN selection according to the priority of the PLMNs, and then performs PLMN selection according to the channel quality of the PLMNs.

[0277] For example, the searched PLMNs are ranked in descending order of priority, at least one PLMN with a priority within a certain range is selected, if the number of the at least one PLMN is one, the one PLMN can be determined as the target PLMN. If the at least one PLMN is a plurality of PLMNs, the plurality of PLMNs can be ranked in descending order of channel quality, and the PLMN with the highest channel quality is selected as the target PLMN.

[0278] Method 2: The NAS of the terminal device first performs PLMN selection according to the channel quality of the PLMNs, and then performs PLMN selection according to the priority of the PLMNs.

[0279] For example, the searched PLMNs are ranked in descending order of channel quality, at least one PLMN with a channel quality within a certain range is selected, if the number of the at least one PLMN is one, the one PLMN can be determined as the target PLMN. If the at least one PLMN is a plurality of PLMNs, the plurality of PLMNs can be ranked in descending order of priority, and the PLMN with the highest priority is selected as the target PLMN.

[0280] Method 3: The NAS of the terminal device considers both the channel quality of the PLMNs and the priority of the PLMNs to perform PLMN selection.

[0281] For example, if the channel quality of the PLMN with the highest priority among the searched PLMNs is X1, the corresponding adjustment amount is delta1, the target channel quality is X1+delta1, the channel quality of the PLMN with the second highest priority is X2, the corresponding adjustment amount is delta2, the target channel quality is X2+delta2, if X1+delta1 is greater than X2+delta2, the PLMN with the highest priority can be selected as the target PLMN, otherwise the PLMN with the second highest priority is selected as the target PLMN. Step 4: The AS of the terminal device acquires the target PLMN selected by the NAS of the terminal device, and further performs cell selection or camping, etc.

[0282] In summary, for a specific terminal or a specific service, the terminal device performs PLMN selection based on the PLMN priority ranking and the channel quality information of the PLMN, which is equivalent to considering the device deployment situation, position, channel quality and other information of the terminal device, and is beneficial to the terminal device to select a suitable PLMN, thereby ensuring continuous transmission of the service.

[0283] Embodiment 3

[0284] Step 1: The AS of the terminal device searches and / or measures the PLMN to obtain the search result of the PLMN and / or the channel quality information of the PLMN.

[0285] Optionally, the terminal device can also obtain the system information of the cell.

[0286] Optionally, the system information can include second indication information, which is used to instruct the terminal device to perform PLMN selection according to the PLMN priority ranking and the first channel quality threshold, or the second indication information is used to instruct the terminal device to perform PLMN selection according to the PLMN priority ranking, the channel quality of the PLMN and the first channel quality threshold.

[0287] Optionally, the second indication information corresponds to a specific terminal, such as an IOT terminal, or a specific service, such as an IOT service.

[0288] Optionally, the above PLMN selection manner corresponds to a specific terminal or a specific service, in which case, it can not be necessary to perform PLMN selection based on the indication of the network device according to the PLMN priority ranking and the channel quality information of the PLMN.

[0289] That is, the terminal device can use the above PLMN selection manner based on the indication of the network device, or can be determined according to the type of the terminal device or the type of the service to be transmitted.

[0290] Optionally, the first channel quality threshold can be notified by the NAS of the terminal device to the AS of the terminal device.

[0291] Optionally, the AS of the terminal device can instruct the NAS of the terminal device to perform PLMN selection according to the PLMN priority ranking and the first channel quality threshold, or according to the PLMN priority ranking, the channel quality of the PLMN and the first channel quality threshold.

[0292] Optionally, the first channel quality threshold corresponds to a specific terminal or a specific service.

[0293] As an example, different services can correspond to different first channel quality thresholds.

[0294] As an example, when the first channel quality threshold corresponds to a specific terminal, the first channel quality threshold can correspond to a specific service of the specific terminal, or can also correspond to all services of the specific terminal.

[0295] Optionally, the first channel quality threshold can be greater than -110dbm.

[0296] Step 2: The AS layer of the terminal device reports the first information to the NAS layer of the terminal device.

[0297] Optionally, the first information can include at least one of the following:

[0298] a. The PLMN whose channel quality is higher than the first channel quality threshold, and such PLMN corresponds to a high quality indication;

[0299] b. The PLMN whose channel quality is lower than the first channel quality threshold, or the PLMN whose channel quality is lower than or equal to the first channel quality threshold and greater than -110dbm;

[0300] c. The channel quality information corresponding to the PLMN;

[0301] d. The first channel quality threshold.

[0302] Optionally, the channel quality information corresponding to the PLMN in information c can be the channel quality corresponding to the PLMN in channel b, and the NAS can not necessarily report the channel quality of the PLMN with a high quality indication.

[0303] Optionally, the channel quality information corresponding to the PLMN in information c can include the channel quality corresponding to all the PLMNs searched by the terminal device.

[0304] Optionally, the channel quality information corresponding to the PLMN in information c can include the channel quality information of the PLMN whose channel quality is higher than the first channel quality threshold among the PLMNs searched by the terminal device.

[0305] Optionally, the AS of the terminal device can report the channel quality information corresponding to all the PLMNs or the channel quality information of the PLMN whose channel quality is higher than the first channel quality threshold based on the indication of the NAS of the terminal device.

[0306] That is, the NAS of the terminal device can indicate to the AS of the terminal device which channel quality information of the PLMN needs to be reported.

[0307] Optionally, in this step 2, the first information can only include the PLMNs whose channel quality is higher than the first channel quality threshold, i.e., only report the PLMNs with high quality indication, which can reduce the signaling overhead and facilitate the assisted NAS selection to the PLMN with better channel quality.

[0308] It should be understood that in some embodiments of the present application, if the terminal device searches for no PLMN whose channel quality is higher than the first channel quality threshold, the terminal device AS can fall back to the legacy network selection manner, e.g., perform PLMN selection according to the second PLMN priority. Alternatively, fall back to the legacy network selection manner after indicating to the terminal device NAS, or instruct the terminal device NAS to perform subsequent PLMN selection according to the instruction of the terminal device AS.

[0309] Step 3: The terminal device NAS performs PLMN selection according to the PLMN priority ranking and the first channel quality threshold.

[0310] Method 1: The terminal device NAS first performs PLMN selection according to the priority of the PLMNs, and then performs PLMN selection according to the channel quality of the PLMNs and the first channel quality threshold.

[0311] For example, first rank the searched PLMNs according to the priority from high to low, select at least one PLMN whose priority is within a certain range, if the number of the at least one PLMN is one, the one PLMN can be determined as the target PLMN. If the at least one PLMN is a plurality of PLMNs, the plurality of PLMNs can be ranked according to the channel quality from high to low, and the PLMN whose channel quality is higher than the first channel quality threshold (i.e., the PLMN with high quality indication) is selected as the target PLMN.

[0312] Method 2: The terminal device NAS first performs PLMN selection according to the channel quality of the PLMNs and the first channel quality threshold, and then performs PLMN selection according to the priority of the PLMNs.

[0313] For example, first rank the searched PLMNs according to the channel quality from high to low, select at least one PLMN whose channel quality is higher than the first channel quality threshold (i.e., the PLMN with high quality indication), if the number of the at least one PLMN is one, the one PLMN can be determined as the target PLMN. If the at least one PLMN is a plurality of PLMNs, the plurality of PLMNs can be ranked according to the priority from high to low, and the PLMN with the highest priority is selected as the target PLMN.

[0314] Step 4: The AS of the terminal device acquires the target PLMN selected by the NAS of the terminal device, and further performs cell selection or camping, etc.

[0315] In summary, for a specific terminal or a specific service, the terminal device performs PLMN selection based on the PLMN priority ranking and the channel quality information of the PLMN, which is equivalent to considering the device deployment situation, location, channel quality, and other information of the terminal device, and is beneficial to the terminal device to select a suitable PLMN, thereby ensuring the continuous transmission of the service.

[0316] The above describes the method of network selection according to an embodiment of the present application from the perspective of a terminal device, and the following describes the method of network selection according to another embodiment of the present application from the perspective of a network device. Figure 2 The above describes the method of network selection according to an embodiment of the present application from the perspective of a terminal device, and the following describes the method of network selection according to another embodiment of the present application from the perspective of a network device. Figure 3 The above describes the method of network selection according to an embodiment of the present application from the perspective of a terminal device, and the following describes the method of network selection according to another embodiment of the present application from the perspective of a network device.

[0317] Figure 3 FIG. 3 is a schematic flowchart of a method 300 of network selection according to another embodiment of the present application, which can be performed by a network device in the communication system shown in FIG. 1, and the method 300 includes the following steps. Figure 1 The method 300 includes the following steps. Figure 3 The method 300 includes the following steps.

[0318] S310: The network device sends indication information to the terminal device, where the indication information is used to indicate the manner of public land mobile network (PLMN) selection performed by the terminal device.

[0319] In some embodiments of the present application, the network device can send the indication information to the terminal device according to the device type of the terminal, the device deployment of the UE, the location of the UE, or the channel quality of the network, etc.

[0320] In some embodiments of the present application, the indication information is used to indicate that the terminal device performs PLMN selection based on a first PLMN priority ranking, and the first PLMN priority ranking is different from a predefined second PLMN priority ranking.

[0321] In some embodiments of the present application, the network device can indicate the first PLMN priority ranking to the terminal device according to the device type of the terminal, the device deployment of the UE, the location of the UE, or the channel quality of the network, etc.

[0322] In some embodiments of the present application, the first PLMN priority ranking corresponds to a specific terminal or a specific service.

[0323] In some embodiments of the present application, the indication information is used to instruct the terminal device to perform PLMN selection according to a PLMN priority and channel quality information of the PLMN; or

[0324] The indication information is used to instruct the terminal device to perform PLMN selection according to a PLMN priority and a first channel quality threshold; or

[0325] The indication information is used to instruct the terminal device to perform PLMN selection according to a PLMN priority, a first channel quality threshold and channel quality information of the PLMN.

[0326] In some embodiments of the present application, the indication information corresponds to a specific terminal or a specific service.

[0327] In some embodiments of the present application, the indication information is sent through a system message or dedicated signaling.

[0328] It should be understood that the indication information in the method 300 can correspond to the first indication information and the second indication information in the method 200, and specific implementation can refer to the related implementation of the first indication information and the second indication information in the method 200. For the sake of brevity, it will not be repeated here.

[0329] The method embodiments of the present application are described in detail above in combination with Figure 2 to Figure 3 The device embodiments of the present application are described in detail below in combination with Figure 4 to Figure 7 It should be understood that the device embodiments correspond to the method embodiments, and similar descriptions can refer to the method embodiments.

[0330] Figure 4 A schematic block diagram of a terminal device 400 according to an embodiment of the present application is shown. As Figure 4 shown, the terminal device 400 includes:

[0331] A processing unit 410 is configured to perform PLMN selection according to a priority ordering of a public land mobile network (PLMN) and / or channel quality information of the PLMN.

[0332] In some embodiments, the processing unit 410 is specifically configured to:

[0333] The terminal device performs PLMN selection according to a first PLMN priority ordering, wherein the first PLMN priority ordering is different from a predefined second PLMN priority ordering.

[0334] In some embodiments, the first PLMN priority ordering corresponds to a specific terminal, or the first PLMN priority ordering corresponds to a specific service, or the first PLMN priority ordering corresponds to a specific service of the terminal device.

[0335] In some embodiments, the first PLMN priority ranking is indicated by a network device or predefined.

[0336] In some embodiments, the processing unit 410 is further configured to:

[0337] In a case that the first indication information of the network device is received, performing PLMN selection according to the first PLMN priority ranking, wherein the first indication information is used to instruct the terminal device to perform PLMN selection based on the first PLMN priority ranking.

[0338] In some embodiments, the first indication information corresponds to a specific terminal or a specific service.

[0339] In some embodiments, the first indication information is sent through system information or dedicated signaling.

[0340] In some embodiments, the processing unit 410 is further configured to:

[0341] performing PLMN selection according to the first information and the first PLMN priority, wherein the first information comprises search results of the PLMNs and / or channel quality information of the PLMNs reported by an access stratum (AS) of the terminal device to a non-access stratum (NAS) of the terminal device.

[0342] In some embodiments, the processing unit 410 is further configured to:

[0343] determining, as a target PLMN, a PLMN with the highest priority in the search results of the PLMNs or a PLMN with a priority higher than a first priority threshold.

[0344] In some embodiments, the first priority threshold is predefined or indicated by a network device.

[0345] In some embodiments, the first priority threshold is indicated through system information or dedicated signaling.

[0346] In some embodiments, the processing unit 410 is further configured to:

[0347] performing PLMN selection according to the first information in combination with the PLMN priority ranking and the channel quality information of the PLMNs, wherein the first information comprises search results of the PLMNs and / or channel quality information of the PLMNs reported by an AS of the terminal device to a NAS of the terminal device.

[0348] In some embodiments, the processing unit 410 is further configured to:

[0349] In a case that the second indication information of the network device is received, the first information is used for performing PLMN selection in combination with the PLMN priority ranking and the channel quality information of the PLMNs.

[0350] In some embodiments, the second indication information corresponds to a specific terminal, or the second indication information corresponds to a specific service, or the second indication information corresponds to a specific service of the terminal device.

[0351] In some embodiments, the second indication information is sent through system information or dedicated signaling.

[0352] In some embodiments, the processing unit 410 is further configured to:

[0353] determine a first PLMN set according to the search result of the PLMNs and the PLMN priority ranking;

[0354] determine a target PLMN according to the channel quality information of the PLMNs in the first PLMN set.

[0355] In some embodiments, the first PLMN set includes at least one of the following PLMNs:

[0356] a PLMN with the highest priority in the search result of the PLMNs in the PLMN priority ranking;

[0357] a PLMN with a priority higher than a second priority threshold in the search result of the PLMNs in the PLMN priority ranking.

[0358] In some embodiments, the second priority threshold is indicated by the network device or predefined.

[0359] In some embodiments, the second priority threshold is indicated through system information or dedicated signaling.

[0360] In some embodiments, the target PLMN includes at least one of the following:

[0361] a PLMN with the highest channel quality in the first PLMN set;

[0362] a PLMN with a channel quality higher than a first channel quality threshold in the first PLMN set;

[0363] a PLMN with an indicated high quality channel in the first PLMN set;

[0364] a PLMN whose channel quality in the channel quality information of the PLMN meets a high quality condition.

[0365] In some embodiments, the first channel quality threshold is indicated by a network device or predefined.

[0366] In some embodiments, the first channel quality threshold is indicated by system information or dedicated signaling.

[0367] In some embodiments, the processing unit 410 is further configured to:

[0368] determine a second PLMN set according to the channel quality information of the PLMNs reported by the AS of the terminal device;

[0369] determine a target PLMN in the second PLMN set according to the PLMN priority ranking.

[0370] In some embodiments, the second PLMN set includes at least one of the following PLMNs:

[0371] a PLMN whose channel quality in the channel quality information of the PLMN is the highest;

[0372] a PLMN whose channel quality in the channel quality information of the PLMN is higher than a second channel quality threshold;

[0373] a PLMN whose channel quality in the channel quality information of the PLMN is indicated as high quality by the AS of the terminal device;

[0374] a PLMN whose channel quality in the channel quality information of the PLMN meets a high quality condition.

[0375] In some embodiments, the second channel quality threshold is indicated by a network device or predefined.

[0376] In some embodiments, the second channel quality threshold is indicated by system information or dedicated signaling.

[0377] In some embodiments, the target PLMN includes at least one of the following:

[0378] a PLMN in the second PLMN set whose priority in the PLMN priority ranking is the highest;

[0379] a PLMN in the second PLMN set whose priority in the PLMN priority ranking is higher than a third priority threshold.

[0380] In some embodiments, the third priority threshold is indicated by a network device or predefined.

[0381] In some embodiments, the third priority threshold is indicated by system information or dedicated signaling.

[0382] In some embodiments, the first information comprises at least one of:

[0383] a PLMN whose channel quality satisfies a first condition;

[0384] channel quality information of the PLMN whose channel quality satisfies the first condition;

[0385] channel quality information of all the PLMNs searched by the terminal device.

[0386] In some embodiments, the target PLMN whose channel quality satisfies the first condition comprises at least one of:

[0387] a PLMN whose channel quality satisfies a high quality condition;

[0388] a PLMN indicated as high quality;

[0389] a PLMN whose channel quality does not satisfy the high quality condition.

[0390] In some embodiments, the PLMN whose channel quality satisfies the high quality condition comprises at least one of:

[0391] a PLMN whose channel quality is greater than -110dbm;

[0392] a PLMN whose channel quality is greater than a third channel quality threshold.

[0393] In some embodiments, the PLMN whose channel quality does not satisfy the high quality condition comprises at least one of:

[0394] a PLMN whose channel quality is less than -110dbm;

[0395] a PLMN whose channel quality is less than the third channel quality threshold;

[0396] a PLMN whose channel quality is greater than -110dbm and less than or equal to the third channel quality threshold.

[0397] In some embodiments, the first information further comprises the third channel quality threshold.

[0398] In some embodiments, the processing unit 410 is further configured to:

[0399] In a case where the third indication information is received by the terminal device, the AS sends channel quality information of a specific PLMN and / or the third channel quality threshold to the NAS, where the third indication information is used to indicate reporting of the channel quality information of the specific PLMN and / or the third channel quality threshold.

[0400] In some embodiments, the specific PLMN includes at least one of the following cases:

[0401] All PLMNs searched by the terminal device;

[0402] The PLMN in the all PLMNs whose channel quality is higher than the third channel quality threshold.

[0403] Optionally, in some embodiments, the communication unit can be a communication interface or a transceiver, or an input / output interface of a communication chip or a system on chip. The processing unit can be one or more processors.

[0404] It should be understood that the terminal device 400 according to the embodiments of the present application can correspond to the terminal device in the method embodiments of the present application, and the above and other operations and / or functions of each unit in the terminal device 400 are respectively used to implement the corresponding process of the terminal device in the method 200 shown in FIG. 2. Figure 2 The above and other operations and / or functions of each unit in the terminal device 400 are respectively used to implement the corresponding process of the terminal device in the method 200 shown in FIG. 2. For brevity, they will not be described here.

[0405] Figure 5 is a schematic block diagram of a network device according to an embodiment of the present application. Figure 5 The network device 500 includes:

[0406] The communication unit 510 is configured to send indication information to the terminal device, where the indication information is used to indicate a manner of performing public land mobile network (PLMN) selection by the terminal device.

[0407] In some embodiments, the indication information is used to instruct the terminal device to perform PLMN selection based on a first PLMN priority ranking, where the first PLMN priority ranking is different from a predefined second PLMN priority ranking.

[0408] In some embodiments, the first PLMN priority ranking corresponds to a specific terminal or a specific service.

[0409] In some embodiments, the indication information is used to instruct the terminal device to perform PLMN selection according to a PLMN priority and channel quality information of a PLMN; or

[0410] The indication information is used to instruct the terminal device to perform PLMN selection according to a PLMN priority and a first channel quality threshold; or

[0411] The indication information is used to instruct the terminal device to perform PLMN selection according to a PLMN priority, a first channel quality threshold, and channel quality information of the PLMN.

[0412] In some embodiments, the indication information corresponds to a specific terminal or a specific service.

[0413] In some embodiments, the indication information is sent through a system message or dedicated signaling.

[0414] Optionally, in some embodiments, the communication unit can be a communication interface or a transceiver, or an input / output interface of a communication chip or a system on chip. The processing unit can be one or more processors.

[0415] It should be understood that the network device 500 according to the embodiments of the present application can correspond to the network device in the method embodiments of the present application, and the above and other operations and / or functions of each unit in the network device 500 are respectively used to implement the corresponding process of the network device in the method 300 shown in the embodiments of the present application, which will not be repeated here for brevity. Figure 3 The network device in the method 300 shown in the embodiments of the present application, which will not be repeated here for brevity.

[0416] Figure 6 Fig. 6 is a schematic structural diagram of a communication device 600 according to an embodiment of the present application. Figure 6 The communication device 600 shown in the figure includes a processor 610, which can call and run a computer program from a memory to implement the method in the embodiments of the present application.

[0417] Optionally, as shown in the figure, the communication device 600 can further include a memory 620. The processor 610 can call and run a computer program from the memory 620 to implement the method in the embodiments of the present application. Figure 6 The memory 620 can be a separate device independent of the processor 610, or can be integrated in the processor 610.

[0418] Optionally, as shown in the figure, the communication device 600 can further include a transceiver 630, and the processor 610 can control the transceiver 630 to communicate with other devices, specifically, to send information or data to other devices, or receive information or data sent by other devices.

[0419] Figure 6 The transceiver 630 can include a transmitter and a receiver. The transceiver 630 can further include an antenna, and the number of antennas can be one or more.

[0420] The transceiver 630 can include a transmitter and a receiver. The transceiver 630 can further include an antenna, and the number of antennas can be one or more.

[0421] ​Optionally, the communication device 600 can be specifically a network device of the embodiments of the present application, and the communication device 600 can implement the corresponding processes in the various methods of the embodiments of the present application implemented by the network device. For the sake of brevity, details are not described herein.

[0422] Optionally, the communication device 600 can be specifically a mobile terminal / terminal device of the embodiments of the present application, and the communication device 600 can implement the corresponding processes in the various methods of the embodiments of the present application implemented by the mobile terminal / terminal device. For the sake of brevity, details are not described herein.

[0423] Figure 7 is a schematic structural diagram of a chip of the embodiments of the present application. Figure 7 The chip 700 shown includes a processor 710, which can call and run a computer program from a memory to implement the method in the embodiments of the present application.

[0424] Optionally, as shown in Figure 7 The chip 700 can also include a memory 720. The processor 710 can call and run a computer program from the memory 720 to implement the method in the embodiments of the present application.

[0425] The memory 720 can be a separate device independent of the processor 710, or can be integrated in the processor 710.

[0426] Optionally, the chip 700 can also include an input interface 730. The processor 710 can control the input interface 730 to communicate with other devices or chips, and specifically, can obtain information or data sent by other devices or chips.

[0427] Optionally, the chip 700 can also include an output interface 740. The processor 710 can control the output interface 740 to communicate with other devices or chips, and specifically, can output information or data to other devices or chips.

[0428] Optionally, the chip can be applied to the network device in the embodiments of the present application, and the chip can implement the corresponding processes in the various methods of the embodiments of the present application implemented by the network device. For the sake of brevity, details are not described herein.

[0429] Optionally, the chip can be applied to the mobile terminal / terminal device in the embodiments of the present application, and the chip can implement the corresponding processes in the various methods of the embodiments of the present application implemented by the mobile terminal / terminal device. For the sake of brevity, details are not described herein.

[0430] It should be understood that the chip mentioned in the embodiments of the present application can also be referred to as a system-level chip, a system chip, a chip system, or a system-on-chip chip, etc.

[0431] Figure 8 is a schematic block diagram of a communication system 900 provided by an embodiment of the present application. As shown in the figure, the communication system 900 includes a terminal device 910 and a network device 920. Figure 8

[0432] The terminal device 910 can be configured to implement the corresponding functions of the terminal device in the above method, and the network device 920 can be configured to implement the corresponding functions of the network device in the above method. For brevity, details are not repeated here.

[0433] It should be understood that the processor of the embodiments of the present application can be an integrated circuit chip with processing capability of signals. In the implementation process, each step of the above method embodiments can be completed by integrated logic circuits or instructions in the form of software in the processor. The processor mentioned above can be a general processor, a digital signal processor (Digital Signal Processor, DSP), an application specific integrated circuit (Application Specific Integrated Circuit, ASIC), a field programmable gate array (Field Programmable Gate Array, FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component. The disclosed methods, steps and logic block diagrams in the embodiments of the present application can be implemented or executed. The general processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in conjunction with the embodiments of the present application can be directly embodied as a hardware code processor for execution, or a combination of hardware and software modules in the code processor for execution. The software module can be located in a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register or other mature storage medium in the art. The storage medium is located in the memory, and the processor reads the information in the memory, and combines the hardware to complete the steps of the above method.

[0434] ​It is to be understood that the memory in the embodiments of the present application can be a volatile memory or a nonvolatile memory, or can include both volatile and nonvolatile memory. Among them, the nonvolatile memory can be a read-only memory (Read-Only Memory, ROM), a programmable read-only memory (Programmable ROM, PROM), an erasable programmable read-only memory (Erasable PROM, EPROM), an electrically erasable programmable read-only memory (Electrically EPROM, EEPROM) or a flash memory. The volatile memory can be a random access memory (Random Access Memory, RAM) used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (Static RAM, SRAM), dynamic random access memory (Dynamic RAM, DRAM), synchronous dynamic random access memory (Synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (Double Data Rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (Enhanced SDRAM, ESDRAM), synchronous link dynamic random access memory (Synchlink DRAM, SLDRAM) and direct memory bus random access memory (Direct Rambus RAM, DR RAM). It should be noted that the memory of the system and method described herein is intended to include, but not limited to, these and any other suitable types of memory.

[0435] It should be understood that the above-mentioned memory is exemplary but not limiting, for example, the memory in the embodiments of the present application can also be static random access memory (static RAM, SRAM), dynamic random access memory (dynamic RAM, DRAM), synchronous dynamic random access memory (synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (double data rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (enhanced SDRAM, ESDRAM), synchronous link dynamic random access memory (synch link DRAM, SLDRAM) and direct memory bus random access memory (Direct Rambus RAM, DR RAM) and the like. That is, the memory in the embodiments of the present application is intended to include, but not limited to, these and any other suitable types of memory.

[0436] The embodiment of the present application further provides a computer readable storage medium for storing the computer program.

[0437] Optionally, the computer readable storage medium can be applied to the network device in the embodiment of the present application, and the computer program makes the computer execute the corresponding process realized by the network device in the various methods of the embodiment of the present application, which will not be repeated here for the sake of brevity.

[0438] Optionally, the computer readable storage medium can be applied to the mobile terminal / terminal device in the embodiment of the present application, and the computer program makes the computer execute the corresponding process realized by the mobile terminal / terminal device in the various methods of the embodiment of the present application, which will not be repeated here for the sake of brevity.

[0439] The embodiment of the present application further provides a computer program product comprising computer program instructions.

[0440] Optionally, the computer program product can be applied to the network device in the embodiment of the present application, and the computer program instructions make the computer execute the corresponding process realized by the network device in the various methods of the embodiment of the present application, which will not be repeated here for the sake of brevity.

[0441] Optionally, the computer program product can be applied to the mobile terminal / terminal device in the embodiment of the present application, and the computer program instructions make the computer execute the corresponding process realized by the mobile terminal / terminal device in the various methods of the embodiment of the present application, which will not be repeated here for the sake of brevity.

[0442] The embodiment of the present application further provides a computer program.

[0443] Optionally, the computer program can be applied to the network device in the embodiment of the present application, and when the computer program runs on the computer, makes the computer execute the corresponding process realized by the network device in the various methods of the embodiment of the present application, which will not be repeated here for the sake of brevity.

[0444] Optionally, the computer program can be applied to the mobile terminal / terminal device in the embodiment of the present application, and when the computer program runs on the computer, makes the computer execute the corresponding process realized by the mobile terminal / terminal device in the various methods of the embodiment of the present application, which will not be repeated here for the sake of brevity.

[0445] Those skilled in the art can clearly understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0446] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

[0447] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the above-described device embodiments are only schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms.

[0448] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0449] In addition, each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically independently, or two or more units can be integrated into one unit.

[0450] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application essentially or the parts that contribute to the prior art or parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (Read-Only Memory, ROM), a random access memory (Random Access Memory, RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0451] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for network selection, characterized in that, include: The terminal equipment selects a PLMN based on its priority ranking within the Public Land Mobile Network (PLMN), including: The terminal device selects a PLMN based on a first PLMN priority order, wherein the first PLMN priority order is different from a predefined second PLMN priority order, wherein the second PLMN priority order is RPLMN higher than HPLMN / the first EHPLMN. Wherein, the first PLMN priority ranking corresponds to a specific terminal, or the first PLMN priority ranking corresponds to a specific service, or the first PLMN priority ranking corresponds to a specific service of a specific terminal. The terminal device selects a PLMN based on the first PLMN priority ranking, including: Upon receiving the first indication information from the network device, the terminal device selects a PLMN based on the first PLMN priority order. The first indication information is used to instruct the terminal device to select a PLMN based on the first PLMN priority order, and the first indication information corresponds to a specific terminal or a specific service.

2. The method according to claim 1, characterized in that, The first PLMN priority order is indicated by the network device or is predefined.

3. The method according to claim 1, characterized in that, The first indication information is sent via system information or dedicated signaling.

4. The method according to claim 1, characterized in that, The terminal device selects a PLMN based on the priority of the first PLMN, and also includes: The terminal device selects a PLMN based on the first information and the first PLMN priority, wherein the first information includes the PLMN search results and / or PLMN channel quality information reported by the terminal device's access layer AS to the terminal device's non-access layer NAS.

5. The method according to claim 4, characterized in that, The terminal device selects a PLMN based on the first information and the first PLMN priority, including: The PLMN with the highest priority in the search results of the PLMN, or the PLMN with a priority higher than the first priority threshold, is identified as the target PLMN.

6. The method according to claim 5, characterized in that, The first priority threshold is predefined or indicated by the network device.

7. The method according to claim 5, characterized in that, The first priority threshold is indicated by system information or dedicated signaling.

8. The method according to claim 1, characterized in that, The terminal device selects a PLMN based on the priority ranking of the Public Land Mobile Network (PLMN), and also includes: The terminal device selects a PLMN based on the first information, combined with the PLMN priority ranking and the PLMN channel quality information. The first information includes the PLMN search results and / or the PLMN channel quality information reported by the AS of the terminal device to the NAS of the terminal device.

9. The method according to claim 8, characterized in that, The terminal device selects a PLMN based on the first information, combined with the PLMN priority ranking and the PLMN channel quality information, including: Upon receiving the second instruction information from the network device, the terminal device selects a PLMN based on the first information, combined with the PLMN priority ranking and the PLMN channel quality information. The second instruction information is used to instruct the terminal device to select a PLMN based on the PLMN priority and the PLMN channel quality information.

10. The method according to claim 9, characterized in that, The second indication information corresponds to a specific terminal, or the second indication information corresponds to a specific service, or the second indication information corresponds to a specific service of a specific terminal.

11. The method according to claim 9, characterized in that, The second instruction information is sent via system information or dedicated signaling.

12. The method according to any one of claims 8-11, characterized in that, The terminal device selects a PLMN based on the first information, combined with the PLMN priority ranking and the PLMN channel quality information, including: The first PLMN set is determined based on the search results of the PLMN and the PLMN priority sorting. The target PLMN is determined based on the channel quality information of the PLMNs in the first PLMN set.

13. The method according to claim 12, characterized in that, The first set of PLMNs includes at least one of the following PLMNs: The PLMN with the highest priority in the PLMN priority ranking search results. The search results for the PLMN include PLMNs with a priority higher than the second priority threshold in the PLMN priority ranking.

14. The method according to claim 13, characterized in that, The second priority threshold is indicated by the network device or is predefined.

15. The method according to claim 14, characterized in that, The second priority threshold is indicated by system information or dedicated signaling.

16. The method according to claim 12, characterized in that, The target PLMN includes at least one of the following: The PLMN with the highest channel quality in the first set of PLMNs; The first set of PLMNs contains PLMNs whose channel quality is higher than the first channel quality threshold; The channel quality of the first set of PLMNs is indicated as high quality. The channel quality information of the PLMN refers to PLMNs whose channel quality meets the high-quality condition.

17. The method according to claim 16, characterized in that, The first channel quality threshold is indicated by the network device or is predefined.

18. The method according to claim 17, characterized in that, The first channel quality threshold is indicated by system information or dedicated signaling.

19. The method according to any one of claims 8-11, characterized in that, The terminal device selects a PLMN based on the first information, combined with the PLMN priority ranking and the PLMN channel quality information, including: The second PLMN set is determined based on the channel quality information of the PLMN reported by the AS of the terminal device. Based on the PLMN priority sorting, the target PLMN is determined in the second PLMN set.

20. The method according to claim 19, characterized in that, The second set of PLMNs includes at least one of the following PLMNs: The PLMN with the highest channel quality among the channel quality information of the PLMN; Among the channel quality information of the PLMN, those PLMNs are higher than the second channel quality threshold; The channel quality in the PLMN reported by the AS of the terminal device is indicated as a high-quality PLMN. The channel quality information of the PLMN refers to PLMNs whose channel quality meets the high-quality condition.

21. The method according to claim 20, characterized in that, The second channel quality threshold is indicated by the network device or is predefined.

22. The method according to claim 21, characterized in that, The second channel quality threshold is indicated by system information or dedicated signaling.

23. The method according to claim 19, characterized in that, The target PLMN includes at least one of the following: The PLMN with the highest priority in the PLMN priority sorting in the second PLMN set; The second set of PLMNs includes PLMNs whose priority is higher than the third priority threshold in the PLMN priority sorting.

24. The method according to claim 23, characterized in that, The third priority threshold is indicated by the network device or is predefined.

25. The method according to claim 24, characterized in that, The third priority threshold is indicated by system information or dedicated signaling.

26. The method according to any one of claims 4-11, characterized in that, The first information includes at least one of the following: PLMN whose channel quality satisfies the first condition; The channel quality information of the PLMN whose channel quality satisfies the first condition; The terminal device searches for channel quality information for all PLMNs.

27. The method according to claim 26, characterized in that, The target PLMN whose channel quality satisfies the first condition includes at least one of the following: A PLMN whose channel quality meets the high-quality conditions; Indicated as a high-quality PLMN; PLMN whose channel quality does not meet the high-quality conditions.

28. The method according to claim 27, characterized in that, The PLMN whose channel quality meets the high-quality condition includes at least one of the following: PLMN with channel quality greater than -110dBm; PLMN with channel quality greater than the third channel quality threshold.

29. The method according to claim 27, characterized in that, The PLMN whose channel quality does not meet the high-quality condition includes at least one of the following: PLMNs with channel quality less than -110dBm; PLMN with channel quality less than the third channel quality threshold; PLMN with channel quality greater than -110dBm and less than or equal to the third channel quality threshold.

30. The method according to claim 28, characterized in that, The first information also includes the third channel quality threshold.

31. The method according to claim 28, characterized in that, The method further includes: Upon receiving third indication information from the NAS of the terminal device, the AS of the terminal device sends channel quality information of a specific PLMN and / or the third channel quality threshold to the NAS of the terminal device, wherein the third indication information is used to indicate the reporting of channel quality information of the specific PLMN and / or the third channel quality threshold.

32. The method according to claim 31, characterized in that, The specific PLMN includes at least one of the following: All PLMNs searched by the terminal device; Among all PLMNs, the PLMN with channel quality higher than the third channel quality threshold.

33. A method for network selection, characterized in that, include: The network device sends an instruction message to the terminal device, the instruction message being used to instruct the terminal device on how to select a Public Land Mobile Network (PLMN); The indication information is used to instruct the terminal device to select a PLMN based on a first PLMN priority order, which is different from a predefined second PLMN priority order, wherein the second PLMN priority order is that RPLMN is higher than HPLMN / the first EHPLMN. Wherein, the first PLMN priority ranking corresponds to a specific terminal, or the first PLMN priority ranking corresponds to a specific service, or the first PLMN priority ranking corresponds to a specific service of a specific terminal. The indication information corresponds to a specific terminal or a specific service.

34. The method according to claim 33, characterized in that, The indication information is also used to instruct the terminal device to select a PLMN based on the PLMN priority and the PLMN's channel quality information; or The indication information is also used to instruct the terminal device to select a PLMN based on the PLMN priority and a first channel quality threshold; or The indication information is also used to instruct the terminal device to select a PLMN based on the PLMN priority, the first channel quality threshold, and the PLMN's channel quality information.

35. The method according to any one of claims 33-34, characterized in that, The instruction information is sent via system message or dedicated signaling.

36. A terminal device, characterized in that, include: The processing unit is used to select a PLMN based on the priority ranking of the Public Land Mobile Network (PLMN). The processing unit is specifically used to select a PLMN based on a first PLMN priority order, wherein the first PLMN priority order is different from a predefined second PLMN priority order, wherein the second PLMN priority order is that RPLMN is higher than HPLMN / the first EHPLMN. Wherein, the first PLMN priority ranking corresponds to a specific terminal, or the first PLMN priority ranking corresponds to a specific service, or the first PLMN priority ranking corresponds to a specific service of a specific terminal. The processing unit selects a PLMN based on the priority of the first PLMN, specifically including: Upon receiving the first indication information from the network device, the terminal device selects a PLMN based on the first PLMN priority order. The first indication information is used to instruct the terminal device to select a PLMN based on the first PLMN priority order, and the first indication information corresponds to a specific terminal or a specific service.

37. A network device, characterized in that, include: A communication unit is used to send instruction information to a terminal device, the instruction information being used to instruct the terminal device on how to select a Public Land Mobile Network (PLMN). The indication information is used to instruct the terminal device to select a PLMN based on a first PLMN priority order, which is different from a predefined second PLMN priority order, wherein the second PLMN priority order is that RPLMN is higher than HPLMN / the first EHPLMN. Wherein, the first PLMN priority ranking corresponds to a specific terminal, or the first PLMN priority ranking corresponds to a specific service, or the first PLMN priority ranking corresponds to a specific service of a specific terminal. The indication information corresponds to a specific terminal or a specific service.

38. A terminal device, characterized in that, include: A processor and a memory for storing a computer program, the processor for calling and running the computer program stored in the memory to perform the method as described in any one of claims 1 to 32.

39. A chip, characterized in that, include: A processor for retrieving and running a computer program from memory, causing a device on which the chip is mounted to perform the method as described in any one of claims 1 to 32.

40. A computer-readable storage medium, characterized in that, Used to store a computer program that causes a computer to perform the method as described in any one of claims 1 to 32.

41. A computer program product, characterized in that, It includes computer program instructions that cause a computer to perform the method as described in any one of claims 1 to 32.

42. A network device, characterized in that, include: A processor and a memory for storing a computer program, the processor for calling and running the computer program stored in the memory to perform the method as described in any one of claims 33 to 35.

43. A chip, characterized in that, include: A processor for retrieving and running a computer program from memory, causing a device on which the chip is mounted to perform the method as described in any one of claims 33 to 35.

44. A computer-readable storage medium, characterized in that, Used to store a computer program that causes a computer to perform the method as described in any one of claims 33 to 35.

45. A computer program product, characterized in that, It includes computer program instructions that cause a computer to perform the method as described in any one of claims 33 to 35.

Images