Method, device and system for mobile terminal to access LTE network

Abstract

The technical scheme provided by the embodiments of the present application is a method, device and system for mobile terminal to access LTE network. In the method, when the number of attachment failures or TAU failures reaches a threshold value, the mobile terminal starts a T3402 timer and disables E-UTRA capability, and after the T3402 timer expires, the mobile terminal reattempts to access the LTE network. The length of the T3402 timer is determined by the moving speed of the mobile terminal, and when the moving speed reaches a first value, the value of the T3402 timer is less than a default length. If the mobile terminal moves at a faster speed, it can enter a good coverage area of the LTE network, and at this time, the mobile terminal can quickly access the LTE network. In this way, the efficiency of the mobile terminal accessing the LTE network can be improved during the movement of the mobile terminal, and a good mobile terminal use experience can be provided for the user.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to methods, apparatus and systems for mobile terminals to access LTE networks. Background Technology

[0002] In mobile communication systems, mobile terminals can access the network through attaching or tracking area update (TAU). Specifically, after powering on, a mobile terminal needs to attach to the network to obtain network-allocated resources and perform mobile services. During movement, the mobile terminal can update its location area via TAU to maintain network connectivity.

[0003] In certain scenarios, such as network congestion or significant interference, mobile terminals may experience consecutive network access failures. According to the definition in TS24.301 of the 3rd Generation Partnership Project (3GPP), when a mobile terminal fails to continuously access a Long Term Evolution (LTE) network, a T3402 timer will be started, and the Evolved Universal Terrestrial Radio Access Network (E-UTRA) capability will be disabled. The default duration of the T3402 timer is 12 minutes. Only after the T3402 timer expires can the mobile terminal retry accessing the LTE network. Summary of the Invention

[0004] This application provides a method, apparatus, and system for a mobile terminal to access an LTE network, which can improve the efficiency of the mobile terminal accessing the LTE network during the mobile terminal's movement and provide users with a better mobile terminal user experience.

[0005] In a first aspect, embodiments of this application provide a method for a mobile terminal to access an LTE network, the method being applied to the mobile terminal. The method may include: the number of times the mobile terminal fails to attach or fails to use a Telematics Unit (TAU) reaches a threshold; in response to the threshold, the mobile terminal starts a T3402 timer and disables E-UTRA capability; the duration of the T3402 timer is determined by the mobile terminal's moving speed, and when the moving speed reaches a first value, the duration of the T3402 timer is less than a first default duration; after the T3402 timer expires, the mobile terminal re-searches for an LTE network and sends an attach request to a first network device.

[0006] By implementing the method provided in the first aspect, after the mobile terminal starts the T3402 timer and disables the E-UTRA capability, it may enter an area with good LTE network coverage if it moves at a relatively fast speed. Since the mobile terminal can re-access the LTE network after its own determined T3402 timer expires, without waiting for the default 12-minute period, it can quickly access the LTE network after entering an area with good network coverage. This improves the efficiency of the mobile terminal accessing the LTE network during movement, providing users with a better mobile terminal experience.

[0007] In conjunction with the first aspect, in some embodiments, the first default duration can be the default duration of T3402, which is 12 minutes, or it can be other preset values. This application embodiment does not impose any restrictions.

[0008] In conjunction with the first aspect, in some embodiments, the threshold can be 5 or other preset values, and the embodiments of this application do not impose any restrictions.

[0009] In conjunction with the first aspect, in some embodiments, the threshold number of times the mobile terminal fails to attach can refer to: the mobile terminal sending n attach requests to the second network device in succession; wherein, after each attachment request is sent, no response message is received from the second network device, or an attach rejection message is received from the second network device; n is equal to the threshold.

[0010] In conjunction with the first aspect, in some embodiments, the threshold number of times the mobile terminal fails to use a TAU request can refer to the following: the mobile terminal sends n TAU requests to the second network device in succession; wherein, after each TAU request is sent, no response message is received from the second network device, or a TAU rejection message is received from the second network device; and n is equal to the threshold.

[0011] In conjunction with the first aspect, the number of attachment failures occurring at the threshold number of times a mobile terminal fails may be for the same cell or for different cells.

[0012] In conjunction with the first aspect, when a mobile terminal experiences a threshold number of attachment failures, the mobile terminal can be in a stationary state or in a moving state.

[0013] In conjunction with the first aspect, in some embodiments, the mobile terminal can determine the duration of the T3402 timer in the following ways:

[0014] (1) When the mobile terminal's moving speed reaches a first value, the duration of the T3402 timer determined by the mobile terminal is less than the default duration of the T3402 timer. Here, the first value can be preset, for example, it can be 200km / h, and this embodiment of the application does not limit it.

[0015] In some embodiments, when the mobile terminal's moving speed equals a first value, the duration of timer T3402 is equal to a first duration; when the mobile terminal's moving speed equals a second value, the duration of timer T3402 is equal to a second duration. The second value is greater than the first value, the second duration is less than the first duration, and both the first and second durations are less than the default duration of timer T3402. In other words, the faster the moving speed, the shorter the duration of timer T3402 determined by the mobile terminal.

[0016] In one implementation, the duration of the T3402 timer determined by the mobile terminal varies depending on the moving speed.

[0017] In another implementation, the duration of the T3402 timer determined by the mobile terminal varies depending on the range of movement speed. When the mobile terminal's movement speed reaches a first value, the duration of the T3402 timer determined by the mobile terminal is the duration corresponding to the current range of movement speed of the mobile terminal.

[0018] In other embodiments, when the mobile terminal's moving speed reaches a first value, regardless of the specific speed, the duration of the T3402 timer is a fixed second default duration. This second default duration is less than the first default duration.

[0019] (2) When the mobile terminal’s moving speed is less than the first value, the duration of the T3402 timer determined by the mobile terminal can remain at the default duration.

[0020] In conjunction with the first aspect, in some embodiments, the mobile terminal can also detect its movement speed before activating the T3402 timer and disabling the E-UTRA capability. Here, the mobile terminal can periodically detect its own movement speed after powering on, or it can start detecting its own movement speed when it detects that the number of attachment or TAU failures has reached a threshold. This application embodiment does not limit this.

[0021] In conjunction with the first aspect, in some embodiments, the mobile terminal detects its own movement speed in the following ways:

[0022] (1) The mobile terminal can obtain the real-time location information of the mobile terminal through GNSS such as GPS, BDS, GLONASS, QZSS or SBAS, and then determine the moving distance between the two time points based on the real-time location information of the mobile terminal at any two time points, and calculate the moving speed.

[0023] (2) The mobile terminal can also use the signals monitored by GNSS to calculate the moving speed through the original Doppler observations or the Doppler observations obtained by carrier phase center difference.

[0024] (3) The mobile terminal can measure the acceleration value and integrate the measured acceleration to obtain the moving speed.

[0025] (4) When the mobile terminal is on public transportation (e.g., high-speed rail, bullet train, airplane), the mobile terminal can establish a short-range communication connection with the public transportation through short-range communication technologies such as BT, Wi-Fi, NFC, light fidelity (LiFi), etc., and then obtain the speed information shared by the public transportation based on the short-range communication connection.

[0026] In conjunction with the first aspect, in some embodiments, disabling the E-UTRA capability of a mobile terminal means that the mobile terminal no longer operates on the 4G frequency band and does not search for any signals on the 4G frequency band. Disabling the E-UTRA capability of a mobile terminal can also be seen as the mobile terminal disabling the LTE network.

[0027] In conjunction with the first aspect, in some embodiments, when a mobile terminal moves rapidly and regains E-UTRA capability and sends an attach request to the first network device, it may have already entered a coverage area with good LTE network conditions. Thus, after the mobile terminal sends the attach request to the first network device, it may receive an attach accept message from the network device 200, meaning the mobile terminal may have successfully accessed the LTE network.

[0028] In conjunction with the first aspect, in some embodiments, the mobile terminal may also display a first user interface, which includes a first area. Specifically, before the mobile terminal receives an attach accept message from the first network device, the first area does not display any content, or the first area displays an identifier of the network currently accessed by the mobile terminal; after the mobile terminal receives the attach accept message from the first network device, the first area displays an identifier of the LTE network. This allows the user to be informed of the current connection status between the mobile terminal and the network through the content displayed in the first area.

[0029] Secondly, embodiments of this application provide a mobile terminal, including one or more processors and one or more memories. The one or more memories are coupled to the one or more processors, and the one or more memories are used to store computer program code, which includes computer instructions. When the one or more processors execute the computer instructions, the terminal performs the method described in the first aspect or any possible implementation thereof.

[0030] Thirdly, embodiments of this application provide a computer storage medium including computer instructions that, when executed on a terminal, cause a communication device to perform the method described in the first aspect or any possible implementation thereof.

[0031] Fourthly, embodiments of this application provide a computer program product that, when run on a computer, causes the computer to execute the method described in the first aspect or any possible implementation thereof.

[0032] Fifthly, embodiments of this application provide a mobile communication system, which includes: a mobile terminal, a first network device, and a second network device; wherein the mobile terminal is the mobile terminal described in the second aspect.

[0033] Implementing the technical solution provided in this application, when the number of attachment failures or TAU failures reaches a threshold, the mobile terminal starts a T3402 timer and disables E-UTRA capability. After the T3402 timer expires, it re-attempts to access the LTE network. The duration of the T3402 timer is determined by the mobile terminal's moving speed. When the moving speed reaches a first value, the value of the T3402 timer is less than the default duration. If the mobile terminal moves at a faster speed, it may enter an area with good LTE network coverage, at which point the mobile terminal can quickly access the LTE network. This improves the efficiency of the mobile terminal accessing the LTE network during movement, providing users with a better mobile terminal experience. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the communication system provided in an embodiment of this application;

[0035] Figure 2A A schematic diagram of the hardware structure of a mobile terminal provided in an embodiment of this application;

[0036] Figure 2B A schematic diagram of the software structure of a mobile terminal provided in an embodiment of this application;

[0037] Figure 3 This is a schematic diagram of the hardware structure of the network device provided in the embodiments of this application;

[0038] Figure 4 This is a schematic diagram of the attachment process of a mobile terminal provided in an embodiment of this application;

[0039] Figure 5 A flowchart illustrating a method for a mobile terminal to access an LTE network, provided in an embodiment of this application;

[0040] Figure 6 This is a schematic diagram of the TAU process of a mobile terminal provided in an embodiment of this application;

[0041] Figure 7 A flowchart illustrating another method for a mobile terminal to access an LTE network, provided in an embodiment of this application;

[0042] Figure 8A and Figure 8B This application provides a set of user interfaces implemented on a mobile terminal. Detailed Implementation

[0043] The technical solutions in the embodiments of this application will be clearly and thoroughly described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B; the word "and / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more than two.

[0044] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.

[0045] The term "user interface (UI)" used in the following embodiments of this application refers to the medium interface through which an application or operating system interacts and exchanges information with the user. It realizes the conversion between the internal form of information and the form that the user can accept. The user interface is source code written in a specific computer language such as Java or Extensible Markup Language (XML). The interface source code is parsed and rendered on the electronic device, ultimately presenting content that the user can recognize. A common form of user interface is the graphical user interface (GUI), which refers to a user interface related to computer operation displayed graphically. It can be visible interface elements such as text, icons, buttons, menus, tabs, text boxes, dialog boxes, status bars, navigation bars, and widgets displayed on the screen of an electronic device.

[0046] According to the definition in 3GPP TS 24.301, when a mobile terminal fails to access the LTE network consecutively, a T3402 timer will be started, and the E-UTRA capability will be disabled. The default duration of the T3402 timer is 12 minutes. Only after the T3402 timer expires can the mobile terminal retry accessing the LTE network. In other words, even if the mobile terminal moves to a coverage area with good network conditions within 12 minutes, it still cannot access the LTE network. This mechanism results in low efficiency for mobile terminals accessing the LTE network.

[0047] To address the current issue of low efficiency in mobile terminal access to LTE networks, this application provides a method, apparatus, and system for mobile terminals to access LTE networks. In this method, the mobile terminal can determine the value of timer T3402 based on its own movement speed, instead of using the default duration. When the movement speed reaches a first value, the mobile terminal determines a timer value of T3402 that is less than the default duration, i.e., the timer value is reduced.

[0048] In this embodiment, the default duration of the T3402 timer can be referred to as the first default duration. This first default duration can be 12 minutes as defined in TS 24.301, or it can be other values; this embodiment does not limit this.

[0049] After a mobile terminal starts the T3402 timer and disables the E-UTRA capability, it may enter an area with good LTE network coverage if it moves at a relatively high speed. In the method provided in this application embodiment, since the mobile terminal can re-access the LTE network after its self-determined T3402 timer expires without waiting for the default duration, the mobile terminal can quickly access the LTE network after entering an area with good network coverage, improving the efficiency of LTE network access and providing users with a better mobile terminal experience.

[0050] In the following embodiments of this application, the scenarios in which a mobile terminal fails to continuously access the LTE network may specifically include: Scenario 1. The mobile terminal fails to attach, and the number of attach attempts reaches a preset value; Scenario 2. The mobile terminal fails to perform a TAU (Trust Access Unlocking) operation, and the number of TAU attempts reaches a preset value. Subsequent method embodiments will describe these two scenarios in detail, and will not be repeated here.

[0051] In the following embodiments of this application, disabling the E-UTRA capability of a mobile terminal means that the mobile terminal no longer operates on the 4G frequency band and does not search for any signals on the 4G frequency band. Disabling the E-UTRA capability of a mobile terminal can also be seen as the mobile terminal disabling the LTE network.

[0052] To better describe the method for a mobile terminal to access an LTE network provided in the embodiments of this application, the mobile communication system provided in the embodiments of this application will be introduced first.

[0053] refer to Figure 1 , Figure 1 The architecture of the mobile communication system 10 provided in this application embodiment is shown.

[0054] like Figure 1 As shown, the mobile communication system 10 is an LTE system. The mobile communication system 10 may include: a mobile terminal 100, and a 4G system (evolved packet system, EPS).

[0055] Mobile terminal 100 may include smartphones (such as mobile phones running Android or iOS), wearable devices (such as smartwatches, smart bracelets), tablets, laptops, PDAs, mobile internet devices (MIDs), or other portable devices. Mobile terminal 100 may also be referred to as user equipment (UE).

[0056] Mobile terminal 100 provides a 4G wireless communication solution. In some embodiments, mobile terminal 100 may also provide solutions including 2G / 3G / 5G wireless communication. That is, mobile terminal 100 supports 4G (i.e., LTE), and can also support 2G, 3G, 5G, and even future mobile communication solutions.

[0057] Mobile terminal 100 stores user information. This user information may include the IMSI and can be stored in the subscriber identity module (SIM) card of mobile terminal 100. Mobile terminal 100 can use this user information as an identifier to connect to network device 200, thereby accessing the LTE network and using the resources allocated by the LTE network for mobile services, such as initiating calls, obtaining video resources, obtaining audio resources, etc., using Voice on Long Term Evolution (VoLTE) based on the Internet Protocol Multimedia Subsystem (IMS).

[0058] Mobile terminal 100 can access the LTE network via attach or TAU. Detailed descriptions of the attach and TAU processes can be found in the subsequent method embodiments.

[0059] In this embodiment, when the mobile terminal 100 fails to access the LTE network consecutively, it can start a T3402 timer and disable the E-UTRA capability. After the T3402 timer expires, the mobile terminal 100 re-attempts to access the LTE network. The value of the T3402 timer is determined by the mobile terminal 100 based on its own movement speed. When the movement speed reaches a first value, the T3402 timer value determined by the mobile terminal is less than the default duration of 12 minutes. This ensures that the mobile terminal 100 can quickly access the LTE network after entering a coverage area with good LTE network conditions, improving the efficiency of LTE network access and providing users with a better mobile terminal user experience.

[0060] EPS may include one or more network devices 200. Network devices 200 are used to allocate network resources to mobile terminal 100 after it accesses the LTE network to support mobile services of mobile terminal 100. Network devices 200 may include, for example, 4G base stations, 4G evolved packet core (EPC) devices, etc. The 4G base stations are connected to the EPC devices. Both the number of 4G base stations and the number of EPC devices can be one or more. Wherein:

[0061] 4G base stations can be evolved Node B (eNodeB), access point (AP), transmit / receive point (TRP), central unit (CU), or other network entities.

[0062] EPC equipment may include the following network elements: Mobility Management Entity (MME), Serving Gateway (SGW), Packet Data Network Gateway (PGW), Home Subscriber Server (HSS), and Application Server, etc. The MME is primarily used to provide access control, mobility management, attach and detach, session management (e.g., bearer establishment, modification, and release) for the mobile terminal 100, etc.

[0063] The signal coverage area of ​​a 4G base station can be divided into multiple tracking areas (TAs), or the signal coverage areas of multiple 4G base stations can form a single TA. Mobile terminal 100 needs to register with one or more TAs for paging management by the EPC device. Specifically, the EPC device can page the terminal within the TA registered to the mobile terminal 100, without needing to search the entire network. If an idle terminal moves out of its currently registered TA during movement, it initiates a TAU procedure to inform the EPC device of its new TA.

[0064] refer to Figure 2A , Figure 2A An exemplary structural diagram of a mobile terminal 100 provided in an embodiment of this application is shown.

[0065] Mobile terminal 100 may include: processor 110, external memory interface 120, internal memory 121, universal serial bus (USB) interface 130, charging management module 140, power management module 141, battery 142, antenna 1, antenna 2, mobile communication module 150, wireless communication module 160, audio module 170, speaker 170A, receiver 170B, microphone 170C, headphone jack 170D, sensor module 180, buttons 190, motor 191, indicator 192, camera 193, display screen 194, and subscriber identification module (SIM) card interface 195, etc. The sensor module 180 may include a pressure sensor 180A, a gyroscope sensor 180B, a barometric pressure sensor 180C, a magnetic sensor 180D, an accelerometer sensor 180E, a distance sensor 180F, a proximity sensor 180G, a fingerprint sensor 180H, a temperature sensor 180J, a touch sensor 180K, an ambient light sensor 180L, a bone conduction sensor 180M, etc.

[0066] It is understood that the structures illustrated in the embodiments of this application do not constitute a specific limitation on the mobile terminal 100. In other embodiments of this application, the mobile terminal 100 may include more or fewer components than illustrated, or combine some components, or split some components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0067] Processor 110 may include one or more processing units, such as: application processor (AP), modem processor, graphics processing unit (GPU), image signal processor (ISP), controller, memory, video codec, digital signal processor (DSP), baseband processor, and / or neural network processing unit (NPU), etc. Different processing units may be independent devices or integrated into one or more processors.

[0068] The controller can serve as the central nervous system and command center of the mobile terminal 100. The controller can generate operation control signals based on the instruction opcode and timing signals to control the fetching and execution of instructions.

[0069] The processor 110 may also include a memory for storing instructions and data. In some embodiments, the memory in the processor 110 is a cache memory. This memory can store instructions or data that the processor 110 has just used or that are used repeatedly. If the processor 110 needs to use the instruction or data again, it can retrieve it directly from the memory. This avoids repeated accesses, reduces the waiting time of the processor 110, and thus improves the efficiency of the system.

[0070] The wireless communication function of the mobile terminal 100 can be implemented through antenna 1, antenna 2, mobile communication module 150, wireless communication module 160, modem processor and baseband processor, etc.

[0071] Antenna 1 and antenna 2 are used to transmit and receive electromagnetic wave signals. Each antenna in mobile terminal 100 can be used to cover one or more communication frequency bands. For example, antenna 1 can cover the 4G communication frequency band, and antenna 2 can cover the 2G / 3G / 5G communication frequency band. Different antennas can also be reused to improve antenna utilization. For example, antenna 1 can be reused as a diversity antenna for a wireless local area network. In some other embodiments, the antennas can be used in conjunction with a tuning switch.

[0072] The mobile communication module 150 provides a 4G wireless communication solution for use on the mobile terminal 100. In some embodiments, the mobile communication module 150 may also provide a 2G / 3G / 5G wireless communication solution for use on the mobile terminal 100. The mobile communication module 150 may include at least one filter, switch, power amplifier, low-noise amplifier (LNA), etc. The mobile communication module 150 may receive electromagnetic waves via the antenna 1, and perform filtering, amplification, and other processing on the received electromagnetic waves before transmitting them to the modem processor for demodulation. The mobile communication module 150 may also amplify the signal modulated by the modem processor and convert it into electromagnetic waves for radiation via the antenna 1. In some embodiments, at least some functional modules of the mobile communication module 150 may be housed in the processor 110. In some embodiments, at least some functional modules of the mobile communication module 150 and at least some modules of the processor 110 may be housed in the same device.

[0073] The modem processor may include a modulator and a demodulator. The modulator modulates the low-frequency baseband signal to be transmitted into a mid-to-high frequency signal. The demodulator demodulates the received electromagnetic wave signal into a low-frequency baseband signal. The demodulator then transmits the demodulated low-frequency baseband signal to the baseband processor for processing. After processing by the baseband processor, the low-frequency baseband signal is transmitted to the application processor. The application processor outputs sound signals through an audio device (not limited to speaker 170A, receiver 170B, etc.) or displays images or videos through the display screen 194. In some embodiments, the modem processor may be a separate device. In other embodiments, the modem processor may be independent of the processor 110 and may be housed in the same device as the mobile communication module 150 or other functional modules.

[0074] The wireless communication module 160 can provide solutions for wireless communication applications on the mobile terminal 100, including wireless local area networks (WLAN) (such as wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), and infrared (IR) technologies. The wireless communication module 160 can be one or more devices integrating at least one communication processing module. The wireless communication module 160 receives electromagnetic waves via antenna 2, demodulates and filters the electromagnetic wave signals, and sends the processed signal to processor 110. The wireless communication module 160 can also receive signals to be transmitted from processor 110, frequency modulate and amplify them, and then convert them into electromagnetic waves for radiation via antenna 2.

[0075] In some embodiments, antenna 1 of mobile terminal 100 is coupled to mobile communication module 150, and antenna 2 is coupled to wireless communication module 160, enabling mobile terminal 100 to communicate with networks and other devices via wireless communication technology. The wireless communication technology may include Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (WCDMA), Time Division Code Division Multiple Access (TD-SCDMA), Long Term Evolution (LTE), BT, GNSS, WLAN, NFC, FM, and / or IR technologies, etc. The GNSS may include the Global Positioning System (GPS), the Global Navigation Satellite System (GLONASS), the BeiDou Navigation Satellite System (BDS), the Quasi-Zenith Satellite System (QZSS), the Galileo Satellite Navigation System, and / or satellite-based augmentation systems (SBAS).

[0076] The mobile terminal 100 implements display functions through a GPU, a display screen 194, and an application processor. The GPU is a microprocessor for image processing, connected to the display screen 194 and the application processor. The GPU is used to perform mathematical and geometric calculations and for graphics rendering. The processor 110 may include one or more GPUs, which execute program instructions to generate or modify display information.

[0077] The display screen 194 is used to display images, videos, etc. The display screen 194 includes a display panel. The display panel can be a liquid crystal display (LCD), an organic light-emitting diode (OLED), an active-matrix organic light-emitting diode (AMOLED), a flexible light-emitting diode (FLED), a miniature LED, a microLED, a quantum dot light-emitting diode (QLED), etc. In some embodiments, the mobile terminal 100 may include one or N displays 194, where N is a positive integer greater than 1.

[0078] Internal memory 121 can be used to store computer executable program code, which includes instructions. Processor 110 executes various functional applications and data processing of mobile terminal 100 by running the instructions stored in internal memory 121. Internal memory 121 may include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function (such as sound playback, image playback, etc.), etc. The data storage area may store data created during the use of mobile terminal 100 (such as audio data, phonebook, etc.). Furthermore, internal memory 121 may include high-speed random access memory and may also include non-volatile memory, such as at least one disk storage device, flash memory device, universal flash storage (UFS), etc.

[0079] Pressure sensor 180A is used to sense pressure signals and convert them into electrical signals. In some embodiments, pressure sensor 180A can be disposed on display screen 194. There are many types of pressure sensors 180A, such as resistive pressure sensors, inductive pressure sensors, and capacitive pressure sensors. A capacitive pressure sensor may include at least two parallel plates with conductive material. When force is applied to pressure sensor 180A, the capacitance between the electrodes changes. Mobile terminal 100 determines the pressure intensity based on the change in capacitance. When a touch operation is applied to display screen 194, mobile terminal 100 detects the intensity of the touch operation based on pressure sensor 180A. Mobile terminal 100 can also calculate the touch position based on the detection signal from pressure sensor 180A. In some embodiments, touch operations applied to the same touch position but with different touch operation intensities can correspond to different operation commands. For example: when a touch operation with an intensity less than a first pressure threshold is applied to the SMS application icon, a command to view an SMS is executed. When a touch operation with an intensity greater than or equal to the first pressure threshold is applied to the SMS application icon, a command to create a new SMS is executed.

[0080] The gyroscope sensor 180B can be used to determine the motion attitude of the mobile terminal 100. In some embodiments, the angular velocity of the mobile terminal 100 about three axes (i.e., the x, y, and z axes) can be determined by the gyroscope sensor 180B.

[0081] The accelerometer 180E can detect the magnitude of acceleration of the mobile terminal 100 in various directions (generally three axes). When the mobile terminal 100 is stationary, it can detect the magnitude and direction of gravity. It can also be used to identify the mobile terminal's posture, and can be applied to applications such as screen orientation switching and pedometers.

[0082] The distance sensor 180F is used to measure distance. The mobile terminal 100 can measure distance via infrared or laser.

[0083] Touch sensor 180K, also known as a "touch panel," can be located on display screen 194. The touch sensor 180K and display screen 194 together form a touchscreen, also known as a "touch screen." Touch sensor 180K detects touch operations applied to or near it. The touch sensor can transmit the detected touch operation to the application processor to determine the type of touch event. Visual output related to the touch operation can be provided through display screen 194. In other embodiments, touch sensor 180K may also be located on the surface of mobile terminal 100, in a different position than display screen 194.

[0084] The SIM card interface 195 is used to connect a SIM card. The SIM card can be inserted into or removed from the SIM card interface 195 to make contact with and detach from the mobile terminal 100. The mobile terminal 100 can support one or N SIM card interfaces, where N is a positive integer greater than 1. The SIM card interface 195 can support Nano SIM cards, Micro SIM cards, and other SIM cards. Multiple cards can be inserted into the same SIM card interface 195 simultaneously.

[0085] In some embodiments of this application, the wireless communication module 160 can be used to obtain the real-time location information of the mobile terminal 100 via GNSS such as GPS, BDS, GLONASS, QZSS, or SBAS. The processor 110 can determine the distance the mobile terminal 100 has traveled between any two points in time based on the real-time location information of the mobile terminal 100 at any two points in time, and calculate the travel speed.

[0086] In some embodiments of this application, the processor 110 may also use the wireless communication module 160 to use signals monitored by GNSS to calculate the moving speed through raw Doppler observations or Doppler observations obtained by carrier phase center differential.

[0087] In some embodiments of this application, the processor 110 may use the measurement value of the accelerometer 180E to integrate the measured acceleration to obtain the moving speed.

[0088] In some embodiments of this application, when the mobile terminal 100 is located on public transportation (e.g., high-speed rail, bullet train, airplane), the wireless communication module 160 can establish a short-range communication connection with the public transportation vehicle through short-range communication technologies such as BitTorrent, Wi-Fi, NFC, and Light Fidelity (LiFi), and then obtain speed information shared by the public transportation vehicle based on this short-range communication connection. The processor 110 can be used to parse the signals received by the wireless communication module 160 based on the short-range communication connection to determine the moving speed of the mobile terminal 100.

[0089] In this embodiment, the processor 201 can be used to determine the value of timer T3402 based on the moving speed of the mobile terminal 100 when the mobile terminal 100 fails to continuously access the LTE network, and start timer T3402. When the moving speed reaches a first value, the value of timer T3402 determined by the processor 201 is less than the default duration of 12 minutes, that is, the value of timer T3402 is reduced.

[0090] In this embodiment, the mobile communication module 150 can be used to disable the E-UTRA capability after the T3402 timer starts. The mobile communication module 150 is also used to restore the E-UTRA capability and retry accessing the LTE network after the T3402 timer expires.

[0091] The software system of mobile terminal 100 can adopt a layered architecture, event-driven architecture, microkernel architecture, microservice architecture, or cloud architecture. This application embodiment uses the layered architecture Android system as an example to exemplify the software structure of mobile terminal 100.

[0092] Figure 2B This is a software structure block diagram of the mobile terminal 100 according to an embodiment of this application.

[0093] A layered architecture divides software into several layers, each with a clear role and function. Layers communicate with each other through software interfaces. In some embodiments, the Android system is divided into four layers, from top to bottom: the application layer, the application framework layer, the Android runtime and system libraries, and the kernel layer.

[0094] The application layer can include a series of application packages.

[0095] like Figure 2B As shown, the application package may include applications such as camera, gallery, calendar, call, map, navigation, WLAN, Bluetooth, music, video, and SMS.

[0096] The application framework layer provides application programming interfaces (APIs) and a programming framework for applications in the application layer. The application framework layer includes some predefined functions.

[0097] like Figure 2B As shown, the application framework layer may include a window manager, content provider, view system, phone manager, resource manager, notification manager, etc.

[0098] The window manager is used to manage windowed applications. It can retrieve screen size, determine the presence of a status bar, lock the screen, and capture screenshots, among other things.

[0099] Content providers store and retrieve data, making that data accessible to applications. This data may include videos, images, audio, made and received phone calls, browsing history and bookmarks, phone books, etc.

[0100] A view system includes visual controls, such as controls for displaying text and controls for displaying images. View systems can be used to build applications. A display interface can consist of one or more views. For example, a display interface including a text notification icon could include views for displaying text and views for displaying images.

[0101] The phone manager is used to provide communication functions for the mobile terminal 100. For example, it manages call status (including connection and hang-up).

[0102] The file explorer provides applications with various resources, such as localized strings, icons, images, layout files, video files, and more.

[0103] The notification manager allows applications to display notifications in the status bar. These notifications can be used to deliver informational messages and can disappear automatically after a short pause, requiring no user interaction. For example, the notification manager can be used to notify users of completed downloads or message alerts. The notification manager can also display notifications as icons or scrolling text in the top status bar, such as notifications from background applications, or as dialog boxes on the screen. Examples include displaying text messages in the status bar, emitting sounds, vibrating the mobile device, and flashing indicator lights.

[0104] The Android Runtime consists of core libraries and a virtual machine. The Android runtime is responsible for the scheduling and management of the Android system.

[0105] The core library consists of two parts: one part is the functionalities that need to be called by the Java language, and the other part is the Android core library.

[0106] The application layer and application framework layer run in a virtual machine. The virtual machine executes the Java files of the application layer and application framework layer as binary files. The virtual machine is used to perform functions such as object lifecycle management, stack management, thread management, security and exception management, and garbage collection.

[0107] System libraries can include multiple functional modules. For example: surface manager, media libraries, 3D graphics processing libraries (e.g., OpenGL ES), 2D graphics engines (e.g., SGL), etc.

[0108] The Surface Manager is used to manage the display subsystem and provides the blending of 2D and 3D layers for multiple applications.

[0109] The media library supports playback and recording of various common audio and video formats, as well as still image files. It supports multiple audio and video encoding formats, such as MPEG4, H.264, MP3, AAC, AMR, JPG, and PNG.

[0110] The 3D graphics processing library is used to implement 3D graphics drawing, image rendering, compositing, and layer processing.

[0111] A 2D graphics engine is a graphics engine for 2D drawing.

[0112] The kernel layer is the layer between hardware and software. The kernel layer contains at least the display driver, camera driver, audio driver, and sensor driver.

[0113] refer to Figure 3 , Figure 3 This is a schematic diagram of the structure of the network device 200 provided in an embodiment of this application. Figure 3 The network device 200 shown can be Figure 1 The MME or eNodeB in the communication system 10 shown is not limited in this embodiment.

[0114] like Figure 3 As shown, network device 200 may include: one or more processors 201, memory 202, communication interface 203, transmitter 205, receiver 206, coupler 207, and antenna 208. These components can be connected via bus 204 or other means. Figure 3 Taking a bus connection as an example:

[0115] The communication interface 203 can be used by the network device 200 to communicate with other communication devices, such as mobile terminals or other network devices. Specifically, the communication interface 203 can be an LTE communication interface. Not limited to wireless communication interfaces, the network device 200 can also be configured with a wired communication interface 203 to support wired communication; for example, the backhaul link between one network device 200 and another network device 200 can be a wired communication connection.

[0116] In some embodiments of this application, transmitter 205 and receiver 206 can be considered as a wireless modem. Transmitter 205 can be used to transmit signals output by processor 201. Receiver 206 can be used to receive signals. In network device 200, the number of transmitters 205 and receivers 206 can be one or more. Antenna 208 can be used to convert electromagnetic energy in a transmission line into electromagnetic waves in free space, or to convert electromagnetic waves in free space into electromagnetic energy in a transmission line. Coupler 207 can be used to split mobile communication signals into multiple paths and distribute them to multiple receivers 206. Understandably, the antenna 208 of the network device can be implemented as a massive MIMO (Massively Multi-Size Antenna Array).

[0117] The memory 202 is coupled to the processor 201 and is used to store various software programs and / or multiple sets of instructions. Specifically, the memory 202 may include high-speed random access memory and may also include non-volatile memory, such as one or more disk storage devices, flash memory devices, or other non-volatile solid-state storage devices.

[0118] The memory 202 may store an operating system (hereinafter referred to as the system), such as uCOS, VxWorks, RTLinux, or other embedded operating systems. The memory 202 may also store a network communication program, which can be used to communicate with one or more additional devices, one or more mobile devices, or one or more network devices.

[0119] In this embodiment, the processor 201 can be used to read and execute computer-readable instructions. Specifically, the processor 201 can be used to call a program stored in the memory 202, such as the implementation program of the method for a mobile terminal to access an LTE network provided in one or more embodiments of this application on the network device 200 side, and execute the instructions contained in the program.

[0120] It needs to be explained that, Figure 3 The network device 200 shown is merely one implementation of the embodiments of this application. In actual applications, the network device 200 may include more or fewer components, which is not limited here.

[0121] The following is combined with Figure 1 The mobile communication system 10 shown Figure 2A and Figure 2B The mobile terminal 100 shown and Figure 3 The network device 200 shown describes in detail the method for a mobile terminal to access an LTE network provided in the embodiments of this application.

[0122] The following two embodiments describe the method for a mobile terminal to access an LTE network provided in this application.

[0123] (I) Example 1

[0124] In Example 1, when the mobile terminal 100 fails to attach and the number of attachment attempts reaches a threshold, it starts a T3402 timer and disables the E-UTRA capability. After the T3402 timer expires, the mobile terminal 100 re-attempts to access the LTE network. The value of the T3402 timer is determined by the mobile terminal 100 based on its own movement speed.

[0125] Before proceeding to Example 1, the attachment process involved in Example 1 will be introduced first.

[0126] Attachment is a process in which mobile terminal 100 registers with EPC to obtain services, EPC assigns an Internet Protocol (IP) address to mobile terminal 100, establishes a connection, establishes a default bearer, and generates a security context. Mobile terminal 100 can initiate attachment after powering on or during roaming. Understandably, the timing and purpose of mobile terminal 100 initiating attachment can be found in the relevant content of TS24.301, and will not be elaborated upon here.

[0127] refer to Figure 4 , Figure 4 The attachment procedure for mobile terminal 100 is shown. This procedure can be referenced from the relevant content defined in 3GPP standard TS24.301 5.5.1. Figure 4 The network device 200 in the middle can be an MME. Figure 4 All messages transmitted between the MME and the mobile terminal 100 are transmitted transparently through the eNodeB.

[0128] like Figure 4 As shown, the mobile terminal 100 first sends an attach request to the network device 200 and simultaneously starts the T3410 timer. The value of the T3402 timer can refer to the specifications in TS24.301, for example, it can be 15 seconds.

[0129] One possible scenario is that after receiving the attach request, the network device 200 sends an attach accept message to the mobile terminal 100; when the mobile terminal 100 receives the attach accept message, it stops the T3410 timer and then replies with an accept complete message, thus successfully attaching.

[0130] Another possible scenario is that after receiving the attach request, the network device 200 sends an attach reject message to the mobile terminal 100; when the mobile terminal 100 receives the attach reject message, it stops the T3410 timer, and the attach fails.

[0131] There may be various reasons why mobile terminal 100 may fail to attach, and this application embodiment does not limit the reasons. For example, it may include network congestion, such as too many devices currently attached to network device 200, poor signal of network device 200, large interference between mobile terminal 100 and network device 200, mobile terminal 100 not supporting the public land mobile network (PLMN) it is currently in, the PLMN where mobile terminal 100 is currently in not supporting EPS service, the service option requested by mobile terminal 100 not being configured in the current PLMN, etc.

[0132] In Example 1, the mobile terminal 100 may determine that the current attachment has failed under any of the following circumstances:

[0133] 1. After sending an attach request, the mobile terminal 100 receives an attach reject message.

[0134] 2. No response message was received from network device 200 during the T3410 timer operation period after mobile terminal 100 sent the attach request.

[0135] refer to Figure 5 , Figure 5 The flowchart of the method for a mobile terminal to access an LTE network provided in Embodiment 1 is shown.

[0136] like Figure 5 As shown, the method may include the following steps:

[0137] S110, Mobile terminal 100 failed to attach, and the number of attach attempts reached the threshold.

[0138] For details regarding mobile terminal 100 attachment failure, please refer to [link / reference]. Figure 4 The relevant description may include, for example, the mobile terminal 100 receiving an attach reject message, or not receiving any response message from the network device 200 during the execution of the T3410 timer after sending an attach request.

[0139] The number of times mobile terminal 100 attempts to attach can be determined by the value of an attach attempt counter. Specifically, mobile terminal 100 can maintain an attach attempt counter. The attach attempt counter indicates the number of times mobile terminal 100 attempts to attach but is rejected. The maximum value of the attach attempt counter is the threshold.

[0140] Understandably, the reset and incrementing of the attachment attempt counter can be found in TS24.301 5.5.1. The reset and incrementing of the attachment attempt counter will be briefly described later, and will not be elaborated upon here.

[0141] The threshold can be preset, for example, it can be 5. This application does not limit the threshold.

[0142] S110 means that the number of times the mobile terminal 100 has failed to attach has reached the threshold.

[0143] In a specific example, S110 could be: Mobile device 100 sends n attach requests sequentially, where during the execution of timer T3410 after each attach request, it either does not receive a response message from network device 200 or receives an attach rejection message from network device 200. Here, n is a threshold value. One possibility is that after sending an attach request, mobile device 100 starts timer T3410. If no response message is received from network device 200 during timer T3410, the RRC connection with network device 200 is released after timer T3410 expires, and then another attach request is sent after a certain period (e.g., 10 seconds). Another possibility is that after sending an attach request, mobile device 100 starts timer T3410. If an attach rejection message is received during timer T3410, the RRC connection with network device 200 is released, and then another attach request is sent after a certain period (e.g., 10 seconds).

[0144] In this embodiment, the number of attachment failures of the mobile terminal 100 in S110 may be for the same cell or for different cells, which is not limited here. The mobile terminal 100 may be in a stationary state or in a moving state in S110, which is not limited here.

[0145] In a specific embodiment, in S110, the mobile terminal 100 may reach a threshold number of times it fails to attach to the same cell while in a stationary state.

[0146] S120, the mobile terminal 100 starts the T3402 timer and disables the E-UTRA capability. The duration of the T3402 timer is determined by the moving speed of the mobile terminal 100.

[0147] Mobile terminal 100 can start timer T3402 and simultaneously disable E-UTRA capability. After timer T3402 expires, i.e., after the duration of timer T3402 has elapsed, mobile terminal 100 restores E-UTRA capability.

[0148] In a specific example, according to the definition in TS24.301 10.2, CAUSE OF START T3402: Atattach failure and the attempt counter is equal to 5, that is, the mobile device starts the T3402 timer when the attachment fails and the number of attachment attempts reaches 5.

[0149] In this embodiment, the duration of timer T3402 is determined by the mobile terminal 100 based on its own moving speed. The mobile terminal 100 can detect its own moving speed after S110, or it can periodically detect its own moving speed after power-on; this embodiment does not impose any limitations on this. In this embodiment, the mobile terminal 100 can detect its own moving speed in the following ways:

[0150] (1) The mobile terminal 100 can obtain the real-time location information of the mobile terminal 100 through GNSS such as GPS, BDS, GLONASS, QZSS or SBAS, and then determine the moving distance of the mobile terminal 100 between the two time points based on the real-time location information of the mobile terminal 100 at any two time points, and calculate the moving speed.

[0151] (2) The mobile terminal 100 can also use the signals monitored by GNSS to calculate the moving speed by using the original Doppler observations or the Doppler observations obtained by carrier phase center difference.

[0152] (3) The mobile terminal 100 can measure the acceleration value and integrate the measured acceleration to obtain the moving speed.

[0153] (4) When the mobile terminal 100 is on a public transportation vehicle (e.g., high-speed rail, bullet train, airplane), the mobile terminal 100 can establish a short-range communication connection with the public transportation vehicle through short-range communication technologies such as BT, Wi-Fi, NFC, light fidelity (LiFi), etc., and then obtain the speed information shared by the public transportation vehicle based on the short-range communication connection.

[0154] In Embodiment 1 of this application, the mobile terminal 100 determines the duration of the T3402 timer based on its own moving speed. The following explains how the mobile terminal 100 determines the duration of the T3402 timer in two different scenarios:

[0155] (1) When the moving speed of the mobile terminal 100 reaches the first value, the duration of the T3402 timer determined by the mobile terminal 100 is less than the default duration of the T3402 timer. Here, the first value can be preset, for example, it can be 200km / h, and this embodiment of the application does not limit it.

[0156] The following describes several methods by which the mobile terminal 100 determines the duration of timer T3402 when the mobile terminal 100's moving speed reaches a first value:

[0157] a) When the moving speed of mobile terminal 100 equals the first value, the duration of timer T3402 is equal to the first duration; when the moving speed of mobile terminal 100 equals the second value, the duration of timer T3402 is equal to the second duration. The second value is greater than the first value, the second duration is less than the first duration, and both the first and second durations are less than the default duration of timer T3402. In other words, the faster the moving speed, the shorter the duration of timer T3402 determined by mobile terminal 100.

[0158] In some embodiments, the duration of the T3402 timer determined by the mobile terminal 100 varies depending on the moving speed.

[0159] In other embodiments, the duration of the T3402 timer determined by the mobile terminal varies depending on the speed range. Specifically, the mobile terminal 100 can divide the speed greater than or equal to a first value into multiple non-overlapping intervals, each interval corresponding to a duration. The higher the speed within an interval, the shorter the corresponding duration. The interval division and the duration of each interval can be preset, and this embodiment does not impose any limitations. For example, the mobile terminal 100 can divide a speed greater than 200 km / h into the following intervals: 200 km / h ≤ speed < 220 km / h, 220 km / h ≤ speed < 250 km / h, and 250 km / h ≤ speed < 300 km / h; the durations corresponding to these intervals can be 10 minutes, 8 minutes, and 6 minutes, respectively. Thus, when the mobile terminal 100's speed reaches the first value, the duration of the T3402 timer determined by the mobile terminal 100 is the duration corresponding to the current speed range of the mobile terminal 100.

[0160] b. When the mobile terminal 100 reaches the first moving speed, regardless of the specific speed, the duration of the T3402 timer will be a fixed second default duration. This second default duration is less than the default duration of the T3402 timer. This second default duration can be preset, for example, to 8 minutes; there is no restriction here.

[0161] (2) When the moving speed of the mobile terminal 100 is less than the first value, the duration of the T3402 timer determined by the mobile terminal 100 can remain at the default duration.

[0162] In this embodiment, disabling the E-UTRA capability of the mobile terminal 100 means that the mobile terminal no longer operates on the 4G frequency band and does not search for any signals on the 4G frequency band. Disabling the E-UTRA capability of the mobile terminal can also be seen as disabling the LTE network.

[0163] Understandably, even after disabling E-UTRA capabilities, mobile terminal 100 can still operate on other frequency bands, search for signals on other frequency bands, and access networks of other standards. For example, mobile terminal 100 can also search for signals on 5G / 3G / 2G frequency bands and access 5G / 3G / 2G networks as well as future networks. In some embodiments, mobile terminal 100 can pre-set priorities and access other network standards in order of priority; for example, mobile terminal 100 can prioritize accessing 5G networks, followed by 3G networks, and finally 2G networks.

[0164] In some embodiments, besides disabling E-UTRA capabilities during timer T3402 in S120, mobile terminal 100 may only disable searching for cells that failed to attach in S110 during timer T3402, but may still search for other cells under the LTE standard. This increases the range of cells that mobile terminal 100 can search, further improving the efficiency of mobile terminal 100 accessing the LTE network. In a specific example, if the threshold number of attach failures in S110 are all for the same cell, mobile terminal 100 may disable searching for that cell during timer T3402.

[0165] S130, after the T3402 timer expires, the mobile terminal 100 searches for the LTE network again and initiates an attach.

[0166] That is, after T3420, the mobile terminal 100 can restore its E-UTRA capability, search for the LTE network again, and initiate an attach to access the LTE network.

[0167] S130 is the process by which mobile terminal 100 searches for an LTE network and initiates an attachment. This process can be divided into the following steps:

[0168] 1. Select a neighborhood.

[0169] Mobile terminal 100 first searches for the PLMN requested by the non-access stratum (NAS), scans all radio frequency (RF) channels in the E-UTRA band (i.e., the 4G band) to find the PLMN, searches for the cell with the strongest signal and reads system information to determine the PLMN. If the cell selection criteria are confirmed to meet the S criterion, then it camps on the selected cell. Mobile terminal 100 camps on the cell, meaning mobile terminal 100 has found the LTE network.

[0170] 2. Register in the community.

[0171] Mobile terminal 100 first performs a random access procedure. After successfully establishing an RRC connection, it initiates an attach request to register. Upon successful registration, it successfully accesses the LTE network and can then use various services provided by the network, such as data services and voice services.

[0172] In short, after the T3402 timer expires, mobile terminal 100 can re-search for LTE networks, specifically searching for 4G signals transmitted by 4G base stations. Once an LTE network is found, it can initiate an attach to the corresponding network device 200. The attachment process for mobile terminal 100 can be found in [reference needed]. Figure 4 The process is illustrated. For example, mobile terminal 100 can send an attach request to network device 200 again.

[0173] Understandably, when the mobile terminal 100 moves rapidly, its position during S110 and S130 may change significantly. Therefore, the network device 200 interacting with the mobile terminal 100 during attachment in S110 and S130 may be the same network device or different network devices. Furthermore, if the mobile terminal 100 attempts to attach several times and fails in S110, the network device interacting with the mobile terminal 100 may be one or multiple; this embodiment does not impose such limitations. In this embodiment, the network device interacting with the mobile terminal 100 during attachment in S110 can be referred to as the second network device, and the network device interacting with the mobile terminal 100 during attachment in S130 can be referred to as the first network device.

[0174] When the mobile terminal 100 moves quickly, it may have entered a coverage area with good LTE network conditions when it executes S130. In this case, after executing S130, the mobile terminal 100 can receive the attach accept message sent by the network device 200 and can reply to the network device 200 with the accept complete message, thus successfully attaching and accessing the LTE network.

[0175] According to the technical solution provided in Example 1, after multiple failed attach attempts, if the mobile terminal 100 moves to a coverage area with good LTE network conditions, it can re-access the LTE network after its own determined T3402 timer expires, without waiting for the default 12-minute period. This means the mobile terminal 100 can quickly access the LTE network, improving the efficiency of LTE network access and providing users with a better mobile terminal experience.

[0176] The following is a brief introduction to resetting the attachment attempt counter and incrementing it by 1.

[0177] Mobile terminal 100 may reset the attach attempt counter to 0 in the following situations:

[0178] 1. Mobile terminal is 100% powered on;

[0179] 2. Insert the Universal Subscriber Identity Module (USIM);

[0180] 3. Attachment successful;

[0181] 4. Enter a new TA;

[0182] 5. T3402 timer timed out;

[0183] 6. Start the T3346 timer;

[0184] 7. A new PLMN was selected;

[0185] 8. Receive an attach reject message with the reason #11, #12, #13, #14, #15, #25 or #35;

[0186] 9. The network side initiates detach, and carries the reason as #11, #12, #13, #14, #15 or #25.

[0187] According to the following content in TS24.301 5.5.1.2.6: For the cases b, c, d, l when the "Extended wait time" is ignored, and la when the "Extended wait time CP data" is ignored, if the attach request is neither for emergency bearer services nor for initiating a PDN connection for emergency bearer services with attach type not set to "EPS emergency attach", the attach attempt counter shall be incremented, unless it was already set to 5.

[0188] b) Lower layer failure or release of the NAS signalling connection without "Extended wait time" and without "Extended wait time CP data" received from lower layers before the ATTACH ACCEPT or ATTACH REJECT message is received

[0189] The attach procedure shall be aborted, and the UE shall proceed as described below.

[0190] c) T3410 timeout

[0191] The UE shall abort the attach procedure and proceed as described below. The NAS signalling connection, if any, shall be released locally.

[0192] d)ATTACH REJECT,other EMM cause values than those treated insubclause 5.5.1.2.5,and cases of EMM cause values#22,#25and#31,if consideredas abnormal cases according to subclause 5.5.1.2.5.

[0193] l)"Extended wait time"from the lower layers

[0194] If the ATTACH REQUEST message contained the low priority indicatorset to"MS is configured for NAS signalling low priority",the UE shall starttimer T3346 with the"Extended wait time"value and reset the attach attemptcounter.

[0195] If the ATTACH REQUEST message did not contain the low priorityindicator set to"MS is configured for NAS signalling low priority",the UE isoperating in NB-S1 mode and the UE is not a UE configured to use AC11–15inselected PLMN,then the UE shall start timer T3346 with the"Extended waittime"value and reset the attach attempt counter.

[0196] In other cases the UE shall ignore the"Extended wait time".

[0197] The UE shall abort the attach procedure, stay in the current serving cell, change the state to EMM-DEREGISTERED.ATTEMPTING-TO-ATTACH and apply the normal cell reselection process.

[0198] The UE shall proceed as described below.

[0199] 1a) "Extended wait time CP data" from the lower layers

[0200] If the UE is operating in NB-S1 mode, the UE shall start the timer T3346 with the "Extended wait time CP data" value and reset the attach attempt counter.

[0201] In other cases the UE shall ignore the "Extended wait time CP data".

[0202] The UE shall abort the attach procedure, stay in the current serving cell, change the state to EMM-DEREGISTERED.ATTEMPTING-TO-ATTACH and apply the normal cell reselection process.

[0203] The UE shall proceed as described below.

[0204] The mobile terminal 100 (i.e., UE) may increment the value of the attach attempt counter by 1 in the following several cases:

[0205] For cases b, c, d, and l, if the "extended wait time" is ignored, and for la, the "extended wait time CP data" is ignored, if the attach request is neither for an emergency bearer service nor for initiating a PDN connection for an emergency bearer service whose attach type is not set to "EPS Emergency Attach", if the attach attempt counter value is less than 5, then the attach attempt counter value is incremented by 1. Where:

[0206] Case b refers to a situation where, in the event of a lower-level failure or release of the NAS signaling connection, the mobile terminal 100 does not receive the "extended waiting time" and "extended waiting time CP data" from the lower layer before receiving the attach accept message or attach reject message; the attach process will be aborted, and the mobile terminal 100 will proceed as described below.

[0207] Case c refers to T3410 timeout. Mobile terminal 100 will abort the attach process and proceed as follows: The NAS signaling connection (if any) should be released locally.

[0208] Case d refers to attachment rejection, other than the cause value of EMM as described in 5.5.1.2.5; if it is considered an anomalous case according to clause 5.5.1.2.5, the EMM case results in #22, #25 and #31.

[0209] Case 1 refers to the lower-level "extended waiting time". If the attach reject message contains a low-priority indicator set to "MS configured for low priority NAS signaling", mobile terminal 100 should initiate T3346 with the "extended waiting time" value and reset the connection attempt counter. If the attach request does not contain a low-priority indicator set to "MS configured for low priority NAS signaling", it indicates that mobile terminal 100 is operating in NB-S1 mode and is not a mobile terminal 100 configured to use AC11-15 in the selected PLMN. In this case, mobile terminal 100 should initiate T3346 with the "extended waiting time" value and reset the connection attempt counter. In other cases, mobile terminal 100 will ignore the "extended waiting time". Mobile terminal 100 will abort the attach process, remain in the current serving cell, change the state to EMM-DEregister.ATTEMPTING-TO-ATTACH, and apply the normal cell reselection process. Mobile terminal 100 will proceed as described below.

[0210] Case 1a refers to "Extended Waiting Time CP Data" from a lower layer. If the mobile terminal 100 is operating in NB-S1 mode, the mobile terminal 100 should start the T3346 with the "Extended Waiting Time CP Data" value and reset the connection attempt counter.

[0211] In other cases, mobile terminal 100 will ignore the "extended waiting time CP data". Mobile terminal 100 will abort the attach process, remain in the current serving cell, change the state to EMM-DEregister.ATTEMPTING-TO-ATTACH, and apply the normal cell reselection process. Mobile terminal 100 will proceed as follows.

[0212] (II) Example 2

[0213] In Example 2, when the mobile terminal 100 fails to perform a TAU and the number of TAU attempts reaches a threshold, it starts a T3402 timer and disables the E-UTRA capability. After the T3402 timer expires, the mobile terminal 100 attempts to access the LTE network. The value of the T3402 timer is determined by the mobile terminal 100 based on its own movement speed.

[0214] Before proceeding to Example 2, the TAU process involved in Example 2 will be introduced first.

[0215] TAU is a process by which mobile terminal 100 registers TA-level location information on the network side, periodically indicates online status, performs network-side load balancing, and updates mobile terminal 100 parameters (such as network capabilities). Mobile terminal 100 can initiate a TAU when a new TA is entered and that TA is not in the TA list stored by mobile terminal 100, when the network side initiates a TAU, or when parameters need to be updated. Understandably, the timing and purpose of mobile terminal 100 initiating a TAU can be found in the relevant content of TS24.301, and will not be elaborated upon here.

[0216] refer to Figure 6 , Figure 6 The TAU procedure for mobile terminal 100 is shown. This procedure can be referenced from the relevant content defined in 3GPP standard TS24.3015.5.3. Figure 6 The network device 200 in the middle can be an MME. Figure 6 All messages transmitted between the MME and the mobile terminal 100 are transmitted transparently through the eNodeB.

[0217] like Figure 6As shown, mobile terminal 100 first sends a TAU (tracking area update request) to network device 200 and simultaneously starts timer T3430. The value of timer T3430 can refer to the specifications in TS24.301, for example, it can be 15 seconds.

[0218] One possible scenario is that after receiving the TAU request, network device 200 sends a TAU acceptance message (tracking area update accept) to mobile terminal 100. Upon receiving the TAU acceptance message, mobile terminal 100 stops the T3430 timer. If mobile terminal 100 is configured with a globally unique temporary UE identity (GUTI), it can reply with a TAU complete message (tracking area update complete), thus successfully attaching.

[0219] Another possible scenario is that after receiving the TAU request, the network device 200 sends a TAU rejection message (tracking area update reject) to the mobile terminal 100; when the mobile terminal 100 receives the TAU rejection message, it stops the T3430 timer, and the TAU fails.

[0220] There may be various reasons why mobile terminal 100TAU fails, and this application embodiment does not limit the reasons. For example, it may include network congestion, such as too many devices currently attached to network device 200, poor signal of network device 200, large interference between mobile terminal 100 and network device 200, mobile terminal 100 not supporting the public land mobile network (PLMN) it is currently in, the PLMN where mobile terminal 100 is currently in not supporting EPS service, the service option requested by mobile terminal 100 not being configured in the current PLMN, etc.

[0221] In Embodiment 2, the mobile terminal 100 may determine that the current TAU ​​has failed under any of the following circumstances:

[0222] 1. After sending a TAU request, mobile terminal 100 receives a TAU rejection message.

[0223] 2. No response message was received from network device 200 during the execution period of the T3430 timer after mobile terminal 100 sent the TAU request.

[0224] refer to Figure 7 , Figure 7 The flowchart of the method for a mobile terminal to access an LTE network provided in Embodiment 2 is shown.

[0225] like Figure 7 As shown, the method may include the following steps:

[0226] S210, Mobile terminal 100TAU failed, and the number of TAU attempts reached the threshold.

[0227] For details regarding the mobile terminal 100TAU failure, please refer to [link / reference]. Figure 6 The relevant description may include, for example, the mobile terminal 100 receiving a TAU rejection message, or not receiving any response message from the network device 200 during the execution of the T3430 timer after sending the TAU request.

[0228] The number of times mobile terminal 100 attempts a TAU can be determined by the value of a TAU attempt counter. Specifically, mobile terminal 100 can maintain a TAU attempt counter. The TAU attempt counter indicates the number of times mobile terminal 100 attempts a TAU but is rejected. The maximum value of the TAU attempt counter is the threshold.

[0229] Understandably, the reset and increment of the attempt counter can be found in TS24.301 5.5.1. The reset and increment of the TAU attempt counter will be briefly introduced later, and will not be elaborated upon here.

[0230] The threshold can be preset, for example, it can be 5. This application does not limit the threshold.

[0231] S210 means that the number of times the mobile terminal 100TAU has failed has reached the threshold.

[0232] In a specific example, S210 could be: Mobile device 100 sends n TAU requests sequentially, where during the execution of timer T3430 after each TAU request, it either does not receive a response message from network device 200 or receives a TAU rejection message from network device 200. Here, n is a threshold value. One possibility is that after sending a TAU request, mobile device 100 starts timer T3430. If no response message is received from network device 200 during timer T3430's execution, the RRC connection with network device 200 is released after timer T3430 expires, and then the next TAU ​​request is sent after a certain period (e.g., 10 seconds). Another possibility is that after sending a TAU request, mobile terminal 100 starts timer T3430. If a TAU rejection message is received during timer T3430's execution, the RRC connection with network device 200 is released, and then the next TAU ​​request is sent after a certain period (e.g., 10 seconds).

[0233] In this embodiment, the TAU failure of the mobile terminal 100 in S210 may be for the same cell or for different cells, which is not limited here. The mobile terminal 100 in S210 may be in a stationary state or in a moving state, which is not limited here.

[0234] In a specific embodiment, in S210, the mobile terminal 100 can reach a threshold number of TAU failures in the same cell while in a stationary state.

[0235] S220, the mobile terminal 100 starts the T3402 timer and disables the E-UTRA capability. The duration of the T3402 timer is determined by the moving speed of the mobile terminal 100.

[0236] Mobile terminal 100 can start timer T3402 and simultaneously disable E-UTRA capability. After timer T3402 expires (i.e., after the duration of timer T3402), mobile terminal 100 restores E-UTRA capability.

[0237] In a specific example, according to the definition in TS24.301 10.2, CAUSE OF START T3402: At tracking area updating failure and the attempt counter is equal to 5, that is, the mobile device starts the T3402 timer when the TAU fails and the number of TAU attempts reaches 5.

[0238] In this embodiment, the method and timing by which the mobile terminal 100 detects its own movement speed are the same as in Embodiment 1. Please refer to the relevant description of S120 in Embodiment 1, which will not be repeated here.

[0239] In Embodiment 2 of this application, the mobile terminal 100 determines the duration of the T3402 timer based on its own moving speed in the same way as in Embodiment 1. Please refer to the relevant description of S120 in Embodiment 1, which will not be repeated here.

[0240] In this embodiment, disabling the E-UTRA capability of the mobile terminal 100 means that the mobile terminal no longer operates on the 4G frequency band and does not search for any signals on the 4G frequency band. Disabling the E-UTRA capability of the mobile terminal can also be seen as disabling the LTE network.

[0241] Understandably, even after disabling E-UTRA capabilities, mobile terminal 100 can still operate on other frequency bands, search for signals on other frequency bands, and access networks of other standards. For example, mobile terminal 100 can also search for signals on 5G / 3G / 2G frequency bands and access 5G / 3G / 2G networks as well as future networks. In some embodiments, mobile terminal 100 can pre-set priorities and access other network standards in order of priority; for example, mobile terminal 100 can prioritize accessing 5G networks, followed by 3G networks, and finally 2G networks.

[0242] In some embodiments, besides disabling E-UTRA capabilities during timer T3402 in S220, mobile terminal 100 may only prohibit searching for cells where TAU failed in S210 during timer T3402, but may still search for other cells under the LTE standard. This increases the range of cells that mobile terminal 100 can search, further improving the efficiency of mobile terminal 100 accessing the LTE network. In a specific example, if the threshold number of TAU failures in S210 are all for the same cell, mobile terminal 100 may prohibit searching for that cell during timer T3402.

[0243] S230, after the duration of timer T3402, mobile terminal 100 re-searches for the LTE network and initiates an attach.

[0244] S230 is the same as S130 in Example 1, and can be referred to the relevant description, which will not be repeated here.

[0245] In short, after the T3402 timer expires, mobile terminal 100 can re-search for LTE networks, specifically searching for 4G signals transmitted by 4G base stations. Once an LTE network is found, it can initiate an attach to the corresponding network device 200. The attachment process for mobile terminal 100 can be found in [reference needed]. Figure 4 The process is illustrated. For example, mobile terminal 100 can send an attach request to network device 200 again.

[0246] Understandably, when the mobile terminal 100 moves rapidly, its position during S210 and S230 may change significantly. Therefore, the network device 200 interacting with the mobile terminal 100 during TAU in S210 and during attach in S230 may be the same network device or different network devices. Furthermore, if the mobile terminal 100 attempts TAU several times and fails in S210, there may be one or multiple network devices interacting with it; this embodiment does not impose any limitations on this. In this embodiment, the network device interacting with the mobile terminal 100 during TAU in S210 can be referred to as the second network device, and the network device interacting with the mobile terminal 100 during attach in S230 can be referred to as the first network device.

[0247] When the mobile terminal 100 moves quickly, it may have entered a coverage area with good LTE network conditions when it executes S230. In this case, after executing S230, the mobile terminal 100 can receive the attach accept message sent by the network device 200 and can reply to the network device 200 with the accept complete message, thus successfully attaching and accessing the LTE network.

[0248] Through the technical solution provided in Embodiment 2, after multiple TAU failures, if the mobile terminal 100 moves to a coverage area with good LTE network conditions, it can re-access the LTE network after its self-determined T3402 timer expires, without waiting for the default 12-minute period. This means the mobile terminal 100 can quickly access the LTE network, improving the efficiency of LTE network access and providing users with a better mobile terminal experience.

[0249] The following is a brief introduction to resetting the TAU attempt counter and incrementing it by 1.

[0250] Mobile terminal 100 can reset the TAU attempt counter to 0 in the following situations:

[0251] 1. Attachment successful;

[0252] 2. TAU successful;

[0253] 3. TAU failed, and the reason given was #11, #12, #13, #14, #15, #25 or #35;

[0254] 4. Mobile terminal 100 selected a new PLMN;

[0255] 5. Mobile terminal 100 is in EMM-REGISTERED.ATTEMPTING-TO-UPDATE state and has entered a new TA;

[0256] 6. Mobile terminal 100 is in EMM-REGISTERED.ATTEMPTING-TO-UPDATE state and has started T3402;

[0257] 7. Mobile terminal 100 is in EMM-REGISTERED.ATTEMPTING-TO-UPDATE state and has started T3346;

[0258] According to the following content in TS24.301 5.5.3:

[0259] [1]"Network failure":The UE shall stop timer T3430 if stillrunning.The tracking area updating attempt counter shall be incremented,unless it was already set to 5.

[0260] [2]For the cases b,c,d,la k when the"Extended wait time"is ignored,and ka whenthe"Extended wait time CP data"is ignored,if the tracking areaupdating request is not for initiating a PDN connection for emergency bearerservices,the tracking area updating attempt counter shall be incremented,unless it was already set to 5.

[0261] [3]Abnormal cases in the UE,SMS services not accepted:The UE shallstop timer T3430 if still running.The tracking area updating attempt countershall be incremented,unless it was already set to 5;

[0262] [4]#17(Network failure):The UE shall stop timer T3430 if stillrunning,and shall enter state MM IDLE.The tracking area updating attemptcounter shall be incremented,unless it was already set to 5.

[0263] [5]if the combined tracking area update was successful for EPSservices only and the TRACKING AREA UPDATE ACCEPT message contained an EMMcause value not treated in subclause 5.5.3.3.4.3or the EMM Cause IE is notincluded in the message,the UE shall proceed as follows:The UE shall stoptimer T3430 if still running,and shall enter state MM IDLE.The tracking areaupdating attempt counter shall be incremented,unless it was already set to 5;

[0264] Mobile terminal 100 may increment the TAU attempt counter by 1 in the following situations:

[0265] 1. "Network Failure": If the value of the TAU attempt counter is less than 5, the value of the TAU attempt counter is incremented by 1.

[0266] 2. For cases b, c, d, la, and k, if the TAU request is not for initiating a PDN connection in an emergency, then ignore k when there is "extended waiting time" and ignore ka bearer service when there is "extended waiting time CP data". If the value of the TAU attempt counter is less than 5, then the value of the TAU attempt counter is incremented by 1.

[0267] In case of an abnormal situation in mobile terminal 100, SMS service will not be accepted: If mobile terminal 100 is still running, it should stop T3410. If the value of the TAU attempt counter is less than 5, the value of the TAU attempt counter will be incremented by 1.

[0268] 3.#17 (Network Failure): If T3410 is still running, it should stop T3410 and enter the MMIDLE state. If the TAU attempt counter value is less than 5, the TAU attempt counter value should be incremented by 1.

[0269] 4. If the combined connection succeeds only for EPS service, and the attach accept message contains an EMM reason value not processed under clause 5.5.1.3.4.3, or the message does not contain an EMM reason IE, then the mobile terminal 100 should proceed as follows: If T3410 is still running, it should stop T3410 and enter the MM IDLE state. If the TAU attempt counter value is less than 5, then the TAU attempt counter value should be incremented by 1.

[0270] refer to Figure 8A and Figure 8B This illustrates a set of user interfaces implemented on a mobile terminal 100 according to an embodiment of this application.

[0271] like Figure 8A and Figure 8B As shown, the user interface of the mobile terminal 100 displays a status bar, which includes a network identifier. The network identifier indicates the network currently accessed by the mobile terminal. The network identifier can be implemented as text, an icon, etc., and this embodiment does not impose any limitations.

[0272] like Figure 8A As shown, during the process of mobile terminal 100 continuously failing to access the LTE network and disabling E-UTRA capability, network identifier 801 can be empty, i.e., no network identifier is displayed. If mobile terminal 100 falls back to a 2G / 3G network or searches for a 5G network during the process of disabling E-UTRA capability, network identifier 801 can display a 2G / 3G / 5G network identifier, such as the text "2G", "3G", or "5G", etc. The scenarios of mobile terminal 100 continuously failing to access the LTE network can be referred to the relevant descriptions in Embodiments 1 and 2.

[0273] like Figure 8B As shown, after the mobile terminal 100 enables E-UTRA capability, if it moves to a coverage area with good LTE network conditions and successfully accesses the LTE network, the network identifier 801 displayed in the user interface can be used to indicate the LTE network, for example, it can be the text "4G".

[0274] In the embodiments of this application, Figure 8A and Figure 8B The user interface shown can be referred to as the first user interface, and the area in the user interface used to display the network identifier can be referred to as the first area.

[0275] The technical solutions described in this application are not limited to the scenarios of mobile terminals accessing LTE networks as described in the above embodiments. They can also be applied to scenarios of mobile terminals accessing other network standards. Other network standards may include, but are not limited to, 2G, 3G, New Radio (NR), and other networks in the future. For example, when the number of attachment failures or TAU failures of a mobile terminal in NR reaches a threshold, a timer can be started, and the NR capability can be disabled. After the timer expires, the mobile terminal 100 re-attempts to access the NR network. The value of the timer is determined by the mobile terminal 100 based on its own movement speed. The specific name of the timer can be referenced in relevant protocols and is not limited here.

[0276] By implementing the technical solutions provided in the embodiments of this application, the efficiency of mobile terminals accessing the network can be improved, providing users with a better mobile terminal user experience.

[0277] The various embodiments of this application can be combined arbitrarily to achieve different technical effects.

[0278] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state drive).

[0279] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM or random access memory (RAM), magnetic disks, or optical disks.

[0280] In summary, the above description is merely an embodiment of the technical solution of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made according to the disclosure of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for a mobile terminal to access an LTE network, characterized in that, The method includes: The number of times the mobile terminal failed to attach or failed TAU reached a threshold; In response to the mobile terminal's attachment failure or TAU failure reaching a threshold number, the mobile terminal starts a T3402 timer. During the operation of the T3402 timer, searching for LTE cells where the mobile terminal's TAU has failed is prohibited, and searching for LTE cells other than those where the mobile terminal's TAU has failed is maintained. The duration of the T3402 timer is determined by the mobile terminal's moving speed. When the mobile terminal's moving speed is less than a first value, the duration of the T3402 timer is equal to a first default duration. When the moving speed is greater than the first value, the duration of the T3402 timer is less than the first default duration, and the greater the mobile terminal's moving speed, the shorter the duration of the T3402 timer. After the T3402 timer expires, the mobile terminal re-searches for the LTE network and sends an attach request to the first network device.

2. The method according to claim 1, characterized in that, The number of times the mobile terminal failed to attach reached a threshold, specifically including: The mobile terminal sends n attach requests to the second network device in succession; wherein, after each attach request is sent, no response message is received from the second network device, or an attach rejection message is received from the second network device; n is equal to the threshold.

3. The method according to claim 1, characterized in that, The number of times the mobile terminal failed TAU reached a threshold, specifically including: The mobile terminal sends n TAU requests to the second network device in succession; wherein, after each TAU request is sent, no response message is received from the second network device, or a TAU rejection message is received from the second network device; n is equal to the threshold.

4. The method according to claim 1, characterized in that, After the mobile terminal sends an attach request to the first network device, the method further includes: The mobile terminal receives the attach accept message sent by the first network device.

5. The method according to claim 4, characterized in that, The method further includes: The mobile terminal displays a first user interface, which includes a first area; Specifically, before the mobile terminal receives the attach accept message sent by the first network device, the first area does not display any content, or the first area displays the identifier of the network currently accessed by the mobile terminal; after the mobile terminal receives the attach accept message sent by the first network device, the first area displays the identifier of the LTE network.

6. The method according to any one of claims 1-5, characterized in that, Before the mobile terminal starts the T3402 timer and disables the E-UTRA capability, the method further includes: The mobile terminal detects the movement speed.

7. The method according to claim 1, characterized in that, The first default duration is 12 minutes.

8. A mobile terminal, characterized in that, The mobile terminal includes: a memory and one or more processors; the memory is coupled to the one or more processors, the memory is used to store computer program code, the computer program code includes computer instructions, and the one or more processors call the computer instructions to cause the mobile terminal to execute: The number of attachment failures or TAU failures has reached a threshold; In response to the mobile terminal's attachment failure or TAU failure reaching a threshold number, a T3402 timer is started. During the operation of the T3402 timer, searching for LTE cells where the mobile terminal's TAU has failed is prohibited, and searching for LTE cells other than those where the mobile terminal's TAU has failed is maintained. The duration of the T3402 timer is determined by the mobile terminal's moving speed. When the mobile terminal's moving speed is less than a first value, the duration of the T3402 timer is equal to a first default duration. When the moving speed is greater than the first value, the duration of the T3402 timer is less than the first default duration, and the greater the mobile terminal's moving speed, the shorter the duration of the T3402 timer. After the T3402 timer expires, the system re-searches for the LTE network and sends an attach request to the first network device.

9. The mobile terminal according to claim 8, characterized in that, The one or more processors are specifically used to invoke the computer instructions to cause the mobile terminal to execute: The system sends n attach requests to the second network device in succession; wherein, after each attach request is sent, no response message is received from the second network device, or an attach rejection message is received from the second network device; n is equal to the threshold.

10. The mobile terminal according to claim 8, characterized in that, The one or more processors are specifically used to invoke the computer instructions to cause the mobile terminal to execute: The system sends n TAU requests to the second network device in succession; wherein, after each TAU request is sent, no response message is received from the second network device, or a TAU rejection message is received from the second network device; n is equal to the threshold.

11. The mobile terminal according to claim 8, characterized in that, The one or more processors are further configured to invoke the computer instructions to cause the mobile terminal to execute: After sending an attach request to the first network device, an attach accept message is received from the first network device.

12. The mobile terminal according to claim 11, characterized in that, The one or more processors are further configured to invoke the computer instructions to cause the mobile terminal to execute: Displaying a first user interface, the first user interface including a first area; Specifically, before the mobile terminal receives the attach accept message sent by the first network device, the first area does not display any content, or the first area displays the identifier of the network currently accessed by the mobile terminal; after the mobile terminal receives the attach accept message sent by the first network device, the first area displays the identifier of the LTE network.

13. The mobile terminal according to any one of claims 8-12, characterized in that, The one or more processors are further configured to invoke the computer instructions to cause the mobile terminal to execute: Detect movement speed before starting the T3402 timer and disabling E-UTRA capability.

14. The mobile terminal according to claim 8, characterized in that, The first default duration is 12 minutes.

15. A computer-readable storage medium comprising instructions, characterized in that, When the instructions are executed on an electronic device, the electronic device causes the electronic device to perform the method as described in any one of claims 1-7.

Images