Mobile terminal device and satellite communication method, apparatus and storage medium thereof

Abstract

This invention provides a mobile terminal device and its satellite communication method, apparatus, and storage medium. The mobile terminal device includes a main processor, a satellite communication module, a SIM card management circuit, and an antenna system. The SIM card management circuit includes a first SIM card switching circuit and a second SIM card switching circuit, the second SIM card switching circuit being used to switch between a cellular SIM card and the satellite communication module. The satellite communication method includes: detecting the cellular network signal status and waking up the satellite communication module when there is no coverage; controlling the second SIM card switching circuit to enable the satellite communication module to read the satellite-specific SIM card to obtain an authentication key; generating and sending an attach request message; processing the SMS content and encapsulating it for transmission to the satellite. This invention achieves intelligent management of cellular and satellite communication authentication through a dual SIM card switching circuit design, eliminating the need for manual SIM card insertion and removal.

Description

Technical Field

[0001] This invention relates to the field of data processing technology, and in particular to a mobile terminal device and its satellite communication method, apparatus and storage medium. Background Technology

[0002] With the increasing global demand for communication, especially in remote areas, oceans, deserts, polar regions, and scenarios where natural disasters paralyze terrestrial communication infrastructure, satellite communication has become a crucial means of ensuring emergency communication. Existing mobile terminals with integrated satellite communication functions typically use separate SIM card slots to manage authentication information for cellular and satellite communications. Users need to manually insert and switch between a regular cellular SIM card and a dedicated satellite SIM card, a cumbersome process that also increases the risk of losing the cards.

[0003] Furthermore, existing technologies typically lack a unified SIM card resource sharing mechanism between the satellite communication module and the main processor, requiring the terminal to be configured with multiple physical SIM card slots to support cellular and satellite communication functions respectively. This not only increases hardware costs and device size but also reduces the ease with which users can quickly switch to satellite communication mode in emergency scenarios, affecting the practicality and user experience of satellite communication functions in mobile terminal devices. Summary of the Invention

[0004] The main objective of this invention is to solve the technical problem that existing mobile terminal devices require manual insertion and removal of cellular communication SIM cards and satellite communication SIM cards, making intelligent management impossible. This invention provides a mobile terminal device, characterized in that the mobile terminal device comprises: The main processor has a first SIM interface and a second SIM interface, used to process cellular communication protocols and satellite communication control commands; The satellite communication module is connected to the main processor via a control link and is used to establish a communication link with the satellite and perform data transmission and reception. A SIM card management circuit is used to manage the SIM card switching of the mobile terminal device. The SIM card management circuit includes a first SIM card switching circuit and a second SIM card switching circuit. The input terminal of the first SIM card switching circuit is connected to the first SIM card slot and the eSIM chip respectively, and the output terminal is connected to the first SIM interface of the main processor, which is used to switch between the physical SIM card and the embedded SIM. The first input terminal of the second SIM card switching circuit is connected to the second SIM card slot, the second input terminal is connected to the SIM interface of the satellite communication module, and the output terminal is connected to the second SIM interface of the main processor, which is used to switch between the cellular SIM card and the satellite communication module; The antenna system, connected to the main processor and satellite communication module, is used to transmit and receive radio frequency signals.

[0005] The present invention also provides a satellite communication method for the mobile terminal device, characterized in that the satellite communication method includes: The main processor detects the signal status of the cellular network and determines whether there is cellular network coverage based on the signal status. When the determination result is that there is no cellular network coverage, the main processor sends a wake-up command to the satellite communication module. The main processor controls the second SIM card switching circuit to switch to the second input terminal, so that the SIM interface of the satellite communication module is connected to the second SIM interface of the main processor. The satellite communication module reads the satellite-specific SIM card in the second SIM card slot through the second SIM card switching circuit to obtain the authentication key. The satellite communication module generates an attach request message based on the authentication key, and sends the attach request message to the satellite through the antenna system to obtain an attach accept message from the satellite. The main processor counts and processes the original SMS content input by the user to obtain the SMS to be sent, and sends the SMS to be sent to the satellite communication module through the control link. The satellite communication module encapsulates the SMS to be sent to obtain a data packet, and sends the data packet to the satellite through the antenna system.

[0006] The present invention also provides a satellite communication device for the aforementioned mobile terminal device, characterized in that the satellite communication device comprises: The main processor detects the signal status of the cellular network and determines whether there is cellular network coverage based on the signal status. When the determination result is that there is no cellular network coverage, the main processor sends a wake-up command to the satellite communication module. The main processor controls the second SIM card switching circuit to switch to the second input terminal, so that the SIM interface of the satellite communication module is connected to the second SIM interface of the main processor. The satellite communication module reads the satellite-specific SIM card in the second SIM card slot through the second SIM card switching circuit to obtain the authentication key. The satellite communication module generates an attach request message based on the authentication key, and sends the attach request message to the satellite through the antenna system to obtain an attach accept message from the satellite. The main processor counts and processes the original SMS content input by the user to obtain the SMS to be sent, and sends the SMS to be sent to the satellite communication module through the control link. The satellite communication module encapsulates the SMS to be sent to obtain a data packet, and sends the data packet to the satellite through the antenna system.

[0007] The present invention also provides a computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to perform the steps of the satellite communication method of the mobile terminal device described above.

[0008] The aforementioned mobile terminal device and its satellite communication method, apparatus, and storage medium include a main processor, a satellite communication module, a SIM card management circuit, and an antenna system. The SIM card management circuit includes a first SIM card switching circuit and a second SIM card switching circuit, the second SIM card switching circuit being used to switch between a cellular SIM card and the satellite communication module. The satellite communication method includes: detecting the cellular network signal status and waking up the satellite communication module when there is no coverage; controlling the second SIM card switching circuit to enable the satellite communication module to read the satellite-specific SIM card to obtain the authentication key; generating and sending an attach request message; processing the SMS content and encapsulating it for transmission to the satellite. This invention achieves intelligent management of cellular and satellite communication authentication through a dual SIM card switching circuit design, eliminating the need for manual SIM card insertion and removal.

[0009] Beneficial Effects: This invention, by setting up a second SIM card switching circuit, with its first input terminal connected to the second SIM card slot, its second input terminal connected to the SIM interface of the satellite communication module, and its output terminal connected to the second SIM interface of the main processor, enables satellite-dedicated SIM cards in the same physical SIM card slot to be read by the main processor for cellular communication, and also read by the satellite communication module for satellite network authentication via the switching circuit, thus achieving dynamic sharing of SIM card resources. This hardware architecture avoids the necessity of adding an additional independent SIM card slot for satellite communication functions. Without increasing device size and hardware costs, it achieves identity authentication information management for cellular and satellite communication through circuit switching, solving the problem of manually inserting and removing SIM cards in existing technologies, reducing user operational complexity, and improving the availability of satellite communication functions in emergency scenarios.

[0010] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained in accordance with the structures particularly pointed out in the description, claims and drawings.

[0011] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of one embodiment of the mobile terminal device in this invention; Figure 2 This is a schematic diagram of the first embodiment of the satellite communication method for a mobile terminal device in this invention; Figure 3 This is a schematic diagram of a second embodiment of the satellite communication method for a mobile terminal device according to the present invention; Figure 4 This is a schematic diagram of an embodiment of the satellite communication device of a mobile terminal device according to an embodiment of the present invention. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] The terms "comprising" and "having," and any variations thereof, used in the embodiments of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include other steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0015] To facilitate understanding of this embodiment, a mobile terminal device disclosed in this embodiment of the invention will first be described in detail. For example... Figure 1 As shown, the mobile terminal device includes The mobile terminal device provided in this embodiment includes a main processor 101, a satellite communication module 102, a SIM card management circuit 103, and an antenna system 104. The main processor 101 is provided with a first SIM interface and a second SIM interface for processing cellular communication protocols and satellite communication control commands. The satellite communication module 102 is connected to the main processor 101 through a control link for establishing a communication link with the satellite and transmitting and receiving data.

[0016] Specifically, the main processor 101 in this invention can be understood as a mobile communication processor that supports multiple SIM cards and can simultaneously manage the communication functions of multiple SIM card interfaces. The control link can use a UART interface or other serial communication interfaces to transmit control commands and status information.

[0017] In this embodiment, by configuring the main processor 101 with a dual-interface configuration having a first SIM interface and a second SIM interface, the mobile terminal device can simultaneously support cellular communication and satellite communication functions. The main processor 101 manages authentication for regular cellular communication through the first SIM interface and achieves SIM card resource sharing with the satellite communication module 102 through the second SIM interface. This dual-interface architecture avoids configuring completely independent processors and interface systems for different communication modes, reducing hardware complexity and cost while ensuring functional integrity.

[0018] In one embodiment, such as Figure 1 As shown, the SIM card management circuit 103 includes a first SIM card switching circuit and a second SIM card switching circuit. The input terminals of the first SIM card switching circuit are connected to the first SIM card slot and the eSIM chip, respectively, and the output terminal is connected to the first SIM interface of the main processor 101, used for switching between a physical SIM card and an embedded SIM. The first input terminal of the second SIM card switching circuit is connected to the second SIM card slot, the second input terminal is connected to the SIM interface of the satellite communication module 102, and the output terminal is connected to the second SIM interface of the main processor 101, used for switching between a cellular SIM card and the satellite communication module 102.

[0019] In this embodiment, a second SIM card switching circuit is configured to allow the satellite-dedicated SIM card in the second SIM card slot to dynamically switch between the main processor 101 and the satellite communication module 102. When the main processor 101 detects normal cellular network coverage, the second SIM card switching circuit connects the second SIM card slot to the main processor 101, enabling it to be used as a second cellular SIM card. When the main processor 101 detects no cellular network coverage, the second SIM card switching circuit switches to the second input terminal, allowing the satellite communication module 102 to directly read the authentication key and subscription information from the satellite-dedicated SIM card, completing registration and attachment in the satellite network. This switching mechanism achieves dynamic sharing of SIM card resources, avoiding the need for an additional independent SIM card slot for satellite communication functions. This saves internal space in the mobile terminal device and eliminates the need for users to manually insert and remove SIM cards, improving the convenience for users to quickly switch to satellite communication mode in emergency scenarios.

[0020] In one embodiment, both the first SIM card switching circuit and the second SIM card switching circuit can be implemented using analog switching chips or multiplexers, and the main processor 101 controls the switching via GPIO control signals. A first state is defined as the state where the second SIM card switching circuit is connected to the first input terminal, and a second state is defined as the state where the second SIM card switching circuit is connected to the second input terminal. The main processor 101 switches between the first state and the second state according to the current network coverage status.

[0021] In this embodiment, the SIM card switching circuit is implemented using an analog switch chip or multiplexer, enabling rapid switching while ensuring signal integrity. The switching time is typically on the order of microseconds, without affecting normal communication processes. The main processor 101 can complete the switching operation through simple GPIO level control, eliminating the need for complex external control circuits and reducing system complexity. When the main processor 101 determines through RSSI detection that the cellular network signal is continuously below a preset threshold, it automatically switches the second SIM card switching circuit from the first state to the second state, allowing the satellite communication module 102 to immediately read the satellite-specific SIM card information. This shortens the time interval from no cellular network detection to satellite communication establishment, improving the response speed of emergency communication.

[0022] In one embodiment, the satellite communication module 102 uses a chip supporting the NB-IoT NTN protocol, and integrates a radio frequency transceiver, a baseband processor, and a power amplifier. The satellite communication module 102 operates in either the L-band or S-band, enabling it to establish a communication link with GEO satellites. Upon receiving a wake-up command from the main processor 101, the satellite communication module 102 enters the working state from its sleep state and reads the authentication key from the satellite-specific SIM card via a second SIM card switching circuit.

[0023] In this embodiment, by employing a satellite communication module 102 supporting the NB-IoT NTN protocol, it is compatible with non-terrestrial network communication protocols defined by the 3GPP standard, enabling standardized communication with GEO satellites. The protocol stack inside the satellite communication module 102 is optimized for the long round-trip latency (approximately 240ms to 500ms) and Doppler frequency offset of GEO satellites, including extending the random access response window and implementing a frequency offset compensation algorithm. When the satellite communication module 102 is woken up from its sleep state, the power consumption increases from the milliwatt level in standby to the hundreds of milliwatts to several watts in the operating state. By waking up the satellite communication module 102 only when there is no cellular network coverage, the battery life of the mobile terminal device can be effectively extended, avoiding the satellite communication module 102 from being in a high-power operating state for extended periods.

[0024] In one embodiment, the antenna system 104 includes a cellular communication antenna and a satellite communication antenna. The cellular communication antenna is connected to the main processor 101 and is used to transmit and receive radio frequency signals in the cellular band. The satellite communication antenna is connected to the satellite communication module 102 and is used to transmit and receive radio frequency signals in the satellite band. The satellite communication antenna is designed with the circular polarization characteristics of GEO satellites in mind, optimizing its radiation pattern to achieve maximum gain in the top direction of the mobile terminal device.

[0025] In this embodiment, by separating the cellular communication antenna and the satellite communication antenna, radio frequency interference between the two communication modes is avoided, ensuring the communication quality of each. The satellite communication antenna adopts a circular polarization design, enabling it to receive circularly polarized signals from GEO satellites. Compared to linearly polarized antennas, it has higher receiving gain and stronger resistance to multipath interference. By optimizing the radiation pattern of the satellite communication antenna so that its main lobe points towards the top of the mobile terminal device, optimal signal reception can be achieved when the user holds the device with the top facing the sky. This reduces signal attenuation caused by human body and ground reflections, improving the reliability of the satellite communication link.

[0026] In one embodiment, the mobile terminal device further includes an audio switch 105 and a microphone 106. A first input terminal of the audio switch 105 is connected to the audio output terminal of the main processor 101, a second input terminal of the audio switch 105 is connected to the audio output terminal of the satellite communication module 102, and the output terminal of the audio switch 105 is connected to the microphone 106. The audio switch 105 is controlled by the main processor 101. When the mobile terminal device is operating in cellular communication mode, it switches the microphone 106 to communicate with the main processor 101; when the mobile terminal device is operating in satellite communication mode, it switches the microphone 106 to communicate with the satellite communication module 102.

[0027] In this embodiment, by setting an audio switching switch 105, the signal routing of the microphone 106 is switched between different communication modes. In scenarios such as cellular calls or voice assistants, the main processor 101 controls the audio switching switch 105 to connect the microphone 106 to its own audio codec, utilizing the built-in audio processing unit of the main processor 101 for audio processing such as echo cancellation and noise suppression, fully leveraging the powerful computing capabilities of the main processor 101. In satellite voice call scenarios, the main processor 101 controls the audio switching switch 105 to connect the microphone 106 to the audio output of the satellite communication module 102, allowing the audio signal collected by the microphone 106 to directly enter the audio processor inside the satellite communication module 102. This avoids the latency and bandwidth consumption that may occur when audio data is transmitted between the main processor 101 and the satellite communication module 102 via a digital bus, optimizing the real-time performance and audio quality of satellite calls.

[0028] In one embodiment, the mobile terminal device further includes a proximity sensor 107 and a power management unit 108. The detection output of the proximity sensor 107 is connected to the power management unit 108 or the main processor 101, and is used to detect the distance between the mobile terminal device and a human body. When the proximity sensor 107 detects that the mobile terminal device is close to a human body, it triggers a power back-off mechanism, and the power management unit 108 reduces the transmission power of the satellite communication module 102 to ensure that the specific absorption rate (SAR) of the product meets the radio frequency radiation safety standards.

[0029] In this embodiment, adaptive power control based on distance detection is achieved by setting a proximity sensor 107 and a power management unit 108. The proximity sensor 107 can be an infrared sensor, a capacitive sensor, or an ultrasonic sensor, capable of detecting the distance between the surface of the mobile terminal device and the human body in real time. When the detected distance is less than a preset threshold, it indicates that the mobile terminal device is being used close to the human body. At this time, the power management unit 108 receives a trigger signal from the proximity sensor 107 and immediately reduces the transmission power of the satellite communication module 102, for example, from 23dBm in normal mode to 20dBm in derating mode. This power back-off mechanism ensures that the SAR value of the mobile terminal device is below the international safety standard limit under various usage postures, protecting the health and safety of users, and also meeting the stringent requirements of international certification bodies such as FCC and CE for radio frequency radiation.

[0030] The mobile terminal device provided in this embodiment manages different SIM card resources through the first SIM card switching circuit and the second SIM card switching circuit, enabling the mobile terminal device to flexibly call the corresponding identity authentication information during the switching between cellular and satellite communication modes. This effectively realizes dynamic sharing of SIM card resources, avoids the manual insertion and removal of SIM cards, and improves response speed in emergency scenarios. The dual-input design of the second SIM card switching circuit reduces the complexity of hardware configuration and saves internal space and cost for the mobile terminal device. Simultaneously, the audio switching switch 105 automatically switches the signal path of the microphone 106 according to the communication mode, allowing the mobile terminal device to utilize the powerful audio processing capabilities of the main processor 101 during cellular calls and directly connect to the satellite communication module 102 for audio processing during satellite calls. This avoids the delay caused by the transmission of audio signals between different processors, thereby optimizing call quality, improving system resource utilization, and reducing echo and noise problems caused by improper audio routing.

[0031] Please see Figure 2 One embodiment of the satellite communication method for mobile terminal devices in this application includes: 201. The main processor detects the signal status of the cellular network and determines whether there is cellular network coverage based on the signal status. When the determination result is that there is no cellular network coverage, the main processor sends a wake-up command to the satellite communication module. In this embodiment, the step of detecting the signal status of the cellular network through the main processor and determining whether cellular network coverage exists based on the signal status includes: reading the Received Signal Strength Indicator (RSSI) value of the cellular network through the main processor; comparing the RSSI value with a preset threshold and recording the duration for which the RSSI value is lower than the preset threshold to obtain the duration of signal weakening; when the duration of signal weakening exceeds the preset duration, it is determined that there is no cellular network coverage.

[0032] Specifically, the main processor 101 periodically reads the Received Signal Strength Indicator (RSSI) value of the currently accessed cellular network through its internal radio frequency module. The RSSI value is a physical quantity that characterizes the wireless signal strength, usually measured in dBm; a higher value indicates a stronger signal. Under normal operating conditions, the main processor 101 continuously monitors changes in this RSSI value to determine the cellular network coverage status of the terminal device's location.

[0033] It's important to note that a single drop in RSSI value does not automatically indicate a lack of cellular network coverage. Mobile devices experience brief signal fluctuations during use, such as when entering an elevator, passing through a tunnel, or being in an area obstructed by buildings. In such cases, the RSSI value may briefly drop but then return to normal. Determining no network coverage and activating the satellite communication module based solely on a single detection result would lead to frequent mode switching, increasing power consumption and degrading the user experience.

[0034] In this embodiment, the main processor 101 employs a duration determination mechanism to avoid the aforementioned problems. Specifically, the main processor 101 compares the read RSSI value with a preset threshold. This preset threshold can be configured according to different cellular network standards. For example, for LTE networks, the preset threshold can be set to a value within the range of -110dBm to -120dBm. When the detected RSSI value is lower than the preset threshold, the main processor 101 does not immediately determine that there is no network coverage, but instead starts a timer to record the duration of the signal weakening state.

[0035] During the timing process, the main processor 101 continuously monitors changes in the RSSI value. If the RSSI value recovers to above the preset threshold during the timing period, it indicates that the signal fluctuation is temporary, and the main processor 101 will stop timing and reset the timer to maintain the current cellular communication mode. If the RSSI value remains below the preset threshold, the duration of signal weakening accumulated by the timer will continue to increase.

[0036] When the signal weakening lasts for a duration exceeding a preset time, the main processor 101 determines that there is indeed no effective cellular network coverage at the current location. This preset time can be configured according to the actual application scenario, and is usually set between 30 and 60 seconds, which can both filter out brief signal fluctuations and respond promptly when truly entering an area without coverage. After the determination is completed, the main processor 101 sends a wake-up command to the satellite communication module 102 through the control link. This command can be a specific AT command or a GPIO level signal, triggering the satellite communication module 102 to enter the working state from a low-power sleep state.

[0037] In one specific embodiment, the main processor 101 can also combine other auxiliary information to improve the accuracy of the judgment. For example, the main processor 101 can simultaneously detect whether the terminal device can search for any cellular network cell signal. Even if the signal strength is weak, if cell broadcast information is still present, it indicates that the terminal device is in the edge area of ​​cellular network coverage rather than a completely uncovered area. In addition, the main processor 101 can also detect the availability of Wi-Fi networks. When both no cellular network coverage and no available Wi-Fi network are detected simultaneously, it can more accurately determine that the terminal device is in a communication isolated state, in which case the necessity of activating satellite communication function is stronger.

[0038] After receiving the wake-up command, the power management unit inside the satellite communication module 102 will gradually turn on the power supply to the radio frequency transceiver, baseband processor and other functional modules, and complete the transition from sleep state to working state.

[0039] 202. The main processor controls the second SIM card switching circuit to switch to the second input terminal, so that the SIM interface of the satellite communication module is connected to the second SIM interface of the main processor. The satellite communication module reads the satellite-specific SIM card in the second SIM card slot through the second SIM card switching circuit to obtain the authentication key. In this embodiment, after confirming that the satellite communication module 102 has been woken up and entered the ready state, the main processor 101 needs to control the second SIM card switching circuit to perform a physical path switch, so that the satellite communication module 102 can access the satellite-specific SIM card in the second SIM card slot. The core of this switching process is to change the electrical connection relationship of the SIM card, rerouting the signal line originally connected to the second SIM interface of the main processor 101 to the SIM interface of the satellite communication module 102.

[0040] Specifically, the second SIM card switching circuit can be implemented using an analog switch chip, which contains multiple controllable signal paths. Initially, the second SIM card switching circuit is in the first input state, meaning the SIM card in the second SIM card slot is connected to the second SIM interface of the main processor 101 and can be used as a regular cellular SIM card. When satellite communication is required, the main processor 101 changes the conduction state of the analog switch chip via GPIO control signals, switching the second SIM card switching circuit to the second input state.

[0041] It should be noted that the physical interface of a SIM card includes multiple signal lines, including power line VCC, ground line GND, clock line CLK, reset line RST, and data line DATA. The second SIM card switching circuit needs to synchronously switch these signal lines to ensure that after the switch is completed, the satellite communication module 102 can communicate with the SIM card via the standard ISO 7816 protocol. During the switching process, the main processor 101 temporarily disconnects the power supply to the second SIM card slot to prevent voltage fluctuations during the switch from damaging the SIM card chip. After the switch is completed, power is restored so that the satellite communication module 102 can correctly recognize the SIM card.

[0042] In one specific embodiment, the switching time of the second SIM card switching circuit is typically in the microsecond range. However, considering the SIM card's power-on reset process, the entire switching process can take anywhere from tens to hundreds of milliseconds. After issuing the switching command, the main processor 101 waits for a preset stabilization time to ensure that the circuit switching is completely stable before notifying the satellite communication module 102 to begin reading the SIM card information.

[0043] After receiving the SIM card ready notification from the main processor 101, the satellite communication module 102 sends a reset signal to the SIM card through its SIM interface. Upon receiving the reset signal, the SIM card returns ATR data, which contains basic parameter information of the SIM card. After parsing the ATR data, the satellite communication module 102 confirms the SIM card type and communication protocol, and then accesses the SIM card's file system according to the standard APDU command sequence.

[0044] The satellite-dedicated SIM card stores various types of information, the most crucial of which is the authentication key Ki. This key is a symmetric key pre-written into the SIM card and used for authentication during network access. The satellite communication module 102 selects the file path where the authentication key is stored in the SIM card by sending a SELECT command, and then reads the file content using a READ BINARY command. It should be noted that the authentication key Ki is usually protected by security and cannot be read directly in plaintext, but it can be used by calling the authentication algorithm A3 and encryption algorithm A8 internal to the SIM card.

[0045] During the reading process, the satellite communication module 102 also acquires other necessary subscription information, including the International Mobile Subscriber Identity (IMSI), Mobile Country Code (MCC), and Mobile Network Code (MNC). This information collectively constitutes the identity credentials required for satellite network access. The satellite communication module 102 caches the read information in its internal memory, awaiting use in subsequent attach request message generation steps.

[0046] In another embodiment, if the second SIM card slot contains a regular cellular SIM card instead of a satellite-dedicated SIM card, the satellite communication module 102 will find a file structure mismatch or missing necessary satellite network subscription information when attempting to read the authentication key. In this case, the satellite communication module 102 will report a SIM card type error to the main processor 101. The main processor 101 can then prompt the user to replace the SIM card with the correct satellite-dedicated SIM card via a user interface, or directly disable the satellite communication function to avoid invalid network access attempts.

[0047] After the satellite communication module 102 successfully obtains the authentication key and related subscription information, it will send feedback to the main processor 101 indicating that the SIM card reading is complete. This feedback can be transmitted via the control link. Upon receiving this feedback, the main processor 101 can proceed to the next step of generating the attachment request message. Throughout the entire SIM card reading process, the second SIM card switching circuit remains connected at the second input terminal until the satellite communication ends and it is necessary to switch back to cellular communication mode. Only then will the main processor 101 control the switching circuit to switch back to the first input terminal.

[0048] 203. The satellite communication module generates an attach request message based on the authentication key, and sends the attach request message to the satellite through the antenna system to obtain an attach accept message from the satellite; The step of generating an attach request message using the satellite communication module based on the authentication key includes: calculating the distance between the satellite and the terminal using the satellite communication module based on the orbital altitude of the GEO satellite and the terminal position; calculating the signal propagation delay based on the distance and the electromagnetic wave propagation speed to obtain an initial timing advance; receiving a synchronization signal from the satellite using the satellite communication module; measuring the actual signal round-trip delay; comparing the actual signal round-trip delay with the theoretical signal propagation delay to obtain a delay deviation value; adjusting the initial timing advance based on the delay deviation value to obtain an adjusted timing advance value; and encapsulating the timing advance value into the attach request message.

[0049] Specifically, in terrestrial cellular networks, base stations calculate signal propagation delay based on the distance between the terminal and the base station, and instruct the terminal to send uplink signals in advance using timing lead. This ensures that uplink signals from terminals at different distances arrive at the base station at the same time, avoiding mutual interference. This mechanism also applies to satellite communications, but due to the vast distances between satellites and the complex signal propagation paths, the calculation of timing lead requires more precise processing.

[0050] When generating the attach request message, the satellite communication module 102 calculates an initial timing advance as a reference for adjusting the uplink signal transmission time. This calculation is based on geometric relationships. The satellite communication module 102 reads the orbital altitude parameters of the GEO satellite from its internal memory. These parameters are typically updated through ephemeris information broadcast by the satellite or using nominal values. Simultaneously, the satellite communication module 102 obtains the terminal's current geographic coordinates, including longitude, latitude, and altitude, through the GNSS module.

[0051] Based on spherical geometry, a three-dimensional coordinate system with the Earth's center as the origin can be established. The terminal position and the satellite position correspond to two spatial points in this coordinate system, and the straight-line distance between the two points is the length of the signal propagation path. It should be noted that although GEO satellites remain stationary relative to the ground, their positions are not absolutely fixed and exhibit east-west and north-south drift. Therefore, in actual calculations, the real-time position of the satellite, rather than the ideal nadir position, needs to be considered. The satellite communication module 102 obtains the satellite's three-dimensional coordinates in the geocentric coordinate system by analyzing the ephemeris parameters broadcast by the satellite, and then calculates the accurate distance between the satellite and the terminal using the spatial distance formula.

[0052] Once the distance is obtained, and considering the speed of electromagnetic wave propagation in a vacuum, the one-way delay required for the signal to travel from the terminal to the satellite can be calculated. Multiplying this one-way delay by two gives the theoretical round-trip delay. Timing advance essentially compensates for the signal propagation delay, ensuring that the terminal's uplink transmission time is earlier than the theoretical transmission time, guaranteeing that the uplink signal arrives within the satellite's desired time window. The initial timing advance is the adjustment calculated based on the theoretical propagation delay, and is typically equal to the one-way propagation delay.

[0053] However, theoretical calculations contain certain errors. The speed of signal propagation in the atmosphere deviates from the speed of light in a vacuum due to refraction effects from the ionosphere and troposphere, especially at low elevation angles where the thickness of the atmosphere traversed by the signal path increases, making the refraction effect more pronounced. Furthermore, satellite position drift, terminal positioning errors, and clock synchronization deviations can all cause differences between the actual propagation delay and the theoretically calculated value. Directly using the initial timing advance without correction may cause the uplink signal to arrive at the satellite at a time deviating from the expected value, affecting signal reception quality.

[0054] In this embodiment, the satellite communication module 102 uses a measured correction method to improve the accuracy of the timing advance. The satellite periodically broadcasts a synchronization signal, which contains the timestamp information of the satellite's launch time. After receiving the synchronization signal, the satellite communication module 102 records the local reception time and extracts the satellite launch time from the signal. The difference between the two is the actual propagation delay of the downlink signal. Since the uplink and downlink paths of the GEO satellite communication link are basically symmetrical, the uplink propagation delay can be considered to be approximately equal to the downlink propagation delay. Therefore, twice the measured downlink delay is the actual round-trip time of the signal.

[0055] The satellite communication module 102 compares the measured actual round-trip time with the theoretically calculated signal propagation time; the difference between the two is the time delay deviation. This deviation reflects the difference between the theoretical model and the actual propagation environment. If the time delay deviation is positive, it indicates that the actual propagation delay is greater than the theoretical value, possibly due to atmospheric refraction delay or satellite position offset. If the time delay deviation is negative, it indicates that the actual propagation delay is less than the theoretical value; this situation is relatively rare and may be related to clock synchronization errors.

[0056] Based on the delay deviation value, the satellite communication module 102 adjusts the initial timing advance. The direction of adjustment is consistent with the sign of the deviation value, and the magnitude of the adjustment is proportional to the size of the deviation value. The adjusted timing advance can more accurately reflect the actual signal propagation delay, enabling the terminal's uplink transmission time to receive more precise advance compensation. This adjusted timing advance is encapsulated in the attach request message and sent to the satellite as a field of the message along with other parameters.

[0057] It should be noted that the timing advance adjustment is not completed all at once. After the attach request message is sent, the network equipment on the satellite side, upon receiving the message, will assess the accuracy of the timing advance configured by the terminal based on the actual received uplink signal time. If further deviations exist, the satellite will include a timing advance correction instruction in the attach receive message, guiding the terminal to make a secondary adjustment. This closed-loop adjustment mechanism can continuously optimize time synchronization accuracy in dynamically changing channel environments.

[0058] In another embodiment, if the satellite communication module 102 detects that the delay deviation value exceeds a preset threshold range, it indicates that there is a significant difference between the theoretical calculation and the actual measurement, which may be caused by outdated satellite ephemeris information, inaccurate terminal positioning, or abnormal channel environment. At this time, the satellite communication module 102 can trigger measures such as reacquiring satellite ephemeris information, repositioning the terminal location, or waiting for channel conditions to improve, to avoid using unreliable timing lead parameters for attachment attempts.

[0059] Furthermore, after receiving the attach acceptance message from the satellite, the method further includes: sending a link test data packet to the satellite via the satellite communication module and recording the sending time to obtain a first timestamp; receiving a link test response data packet from the satellite and recording the receiving time to obtain a second timestamp; calculating the actual round-trip time delay (RTD) based on the first and second timestamps and comparing it with the theoretical round-trip time delay calculated based on the orbital altitude of the GEO satellite to obtain a delay deviation value; when the delay deviation value exceeds a preset deviation threshold, recalculating the extended random access response window parameters and frequency compensation parameters based on the delay deviation value to obtain updated communication parameters; and applying the updated communication parameters to subsequent data transmission via the satellite communication module.

[0060] Specifically, after successfully receiving the attach accept message, the satellite communication module 102 will execute a link quality verification process. The completion of the attach process only indicates that a control-level connection has been established between the terminal and the satellite, but the communication parameters used in the attach process are based on theoretical models and preliminary measurements, and there may be estimation errors.

[0061] The satellite communication module 102 actively probes the actual status of the current link by sending link test data packets. These test data packets can be specially designed probe messages or Ping packets conforming to protocol standards, with a small data size to reduce transmission time. At the instant the test data packet is sent, the satellite communication module 102 reads the current time from the local clock and records it as the first timestamp.

[0062] The test data packet is transmitted to the satellite via antenna system 104. After receiving it, the satellite generates a corresponding link test response data packet and returns it to the terminal. When the satellite communication module 102 receives the response data packet, it immediately reads the reception time and records it as a second timestamp. The complete round-trip time (RTD) can be calculated using the time difference between the second timestamp and the first timestamp. This RTD includes uplink propagation delay, satellite-side processing delay, and downlink propagation delay. The satellite processing delay is usually small and stable and can be deducted as a fixed quantity.

[0063] The satellite communication module 102 compares the measured actual round-trip time (RTD) with the theoretical RTD previously calculated based on the GEO satellite orbital altitude and terminal position. The difference between the two is the delay deviation value. The delay deviation value is caused by factors such as ionospheric and tropospheric refraction delay, satellite position drift, and terminal positioning errors.

[0064] The satellite communication module 102 compares the delay deviation value with a preset deviation threshold. If the delay deviation value is less than the threshold, it indicates that the current parameters are basically accurate, and the data transmission phase can proceed directly. If the delay deviation value exceeds the preset deviation threshold, the communication parameters need to be updated.

[0065] The satellite communication module 102 recalculates the extended random access response window parameters based on the measured delay deviation value, using the measured round-trip time delay instead of the theoretically calculated value. The updated window parameters can more accurately match the actual signal propagation delay. Simultaneously, through the transmission and reception process of link test data packets, the satellite communication module 102 can further analyze the spectral characteristics of the received signal, extract more accurate Doppler frequency offset information, and thus optimize the frequency compensation parameters.

[0066] The updated communication parameters are stored in the configuration register of the satellite communication module 102 and applied to subsequent data transmission. When the terminal sends uplink data, it adjusts the transmit carrier frequency using the updated frequency compensation parameters; when waiting to receive downlink data, it configures the receive timing according to the updated window parameters.

[0067] In one specific embodiment, if the delay deviation values ​​measured multiple times consecutively exceed the threshold and show a continuous increasing trend, it may indicate that the terminal is moving rapidly or that the channel environment is undergoing drastic changes. At this time, the satellite communication module 102 can report the abnormal state to the main processor 101, which will then decide whether to re-perform the attachment process or switch back to cellular communication mode.

[0068] 204. The main processor performs character count and processing on the original SMS content input by the user to obtain the SMS to be sent, and sends the SMS to be sent to the satellite communication module through the control link. The satellite communication module encapsulates the SMS to be sent to obtain a data packet, and sends the data packet to the satellite through the antenna system.

[0069] In this embodiment, after the data packet is sent to the satellite via the antenna system, the method further includes: when a user initiates a satellite voice call request, the main processor controls the audio switching switch to switch to the second input terminal, so that the microphone is connected to the audio output terminal of the satellite communication module; the microphone collects audio signals and inputs them to the satellite communication module for audio processing to obtain processed audio data; the satellite communication module encapsulates the processed audio data into a voice data packet, and the voice data packet is sent to the satellite via the antenna system.

[0070] In this embodiment, the main processor 101 detects the cellular network coverage status through a duration determination mechanism, avoiding misjudgments caused by brief signal fluctuations. This allows the mobile terminal device to respond promptly and activate the satellite communication module 102 when it actually enters an area without coverage, improving the response speed of emergency communication. Under the control of the main processor 101, the second SIM card switching circuit dynamically switches the satellite-dedicated SIM card between the main processor 101 and the satellite communication module 102. This allows different modules to share the resources of the same physical SIM card slot, avoiding the need for manual SIM card insertion and removal, and reducing the operational complexity for users in emergency scenarios. Simultaneously, by calculating the initial timing advance based on the GEO satellite orbital altitude and terminal position, and correcting the timing advance using measured synchronization signals, the satellite communication module 102 can generate more accurate attach request message parameters, improving the success rate of random access and reducing the number of retransmissions due to inaccurate parameters. After attachment is completed, link testing and verification are performed, and communication parameters are dynamically updated based on the measured delay deviation. This ensures that the random access response window parameters and frequency compensation parameters used in subsequent data transmission can accurately match the actual channel conditions, thereby optimizing the transmission success rate and reducing communication interruption caused by changes in the channel environment.

[0071] Please see Figure 3 Another embodiment of the satellite communication method for mobile terminal devices in this application includes: 301. The main processor detects the signal status of the cellular network and determines whether there is cellular network coverage based on the signal status. When the determination result is that there is no cellular network coverage, the main processor sends a wake-up command to the satellite communication module. 302. The main processor controls the second SIM card switching circuit to switch to the second input terminal, so that the SIM interface of the satellite communication module is connected to the second SIM interface of the main processor. The satellite communication module reads the satellite-specific SIM card in the second SIM card slot through the second SIM card switching circuit to obtain the authentication key. In this embodiment, steps 301-302 are similar to steps 201-202 in the second embodiment, and will not be described again here.

[0072] 303. The satellite communication module calculates the round-trip time of the signal based on the orbital altitude of the GEO satellite, and expands the random access response window based on the round-trip time of the signal to obtain the expanded random access response window; In this embodiment, the satellite communication module 102 reads the nominal orbital altitude parameters of the GEO satellite from its internal memory. The GEO satellite operates in a geostationary orbit, and its orbital altitude is relatively stable. These parameters can be pre-written into the satellite communication module 102 using configuration information provided by the satellite operator, or obtained by parsing system information broadcast by the satellite.

[0073] The minimum signal propagation distance can be estimated based on the orbital altitude and the terminal's geographical location. For a terminal located directly below the satellite's nadir, the signal propagation distance is approximately equal to the orbital altitude; for a terminal deviating from the nadir, the propagation distance increases due to the viewing angle. The satellite communication module 102 uses a simplified geometric model for rapid estimation, multiplying the orbital altitude by a correction factor related to the terminal's location to obtain an approximate signal propagation distance. This correction factor can be obtained by looking up the terminal's latitude information in a table, avoiding complex spherical trigonometry calculations.

[0074] After obtaining the signal propagation distance, dividing it by the speed of electromagnetic wave propagation in free space yields the one-way propagation delay. Multiplying the one-way delay by two gives an estimate of the round-trip delay. Although this estimate does not consider details such as atmospheric refraction, it is sufficient as a reference value for window expansion.

[0075] The expansion process of the random access response window is based on the standard window configuration of terrestrial cellular networks. In the standard configuration, the window start time is set after a fixed delay following the transmission of the random access preamble, and the window duration is also predetermined. These parameters are designed for the coverage radius of terrestrial networks and cannot adapt to the long latency characteristics of satellite communications.

[0076] The satellite communication module 102 delays the start time of the window based on the calculated round-trip time. The delay is equal to the difference between the satellite round-trip time and the standard delay of the ground network. Simultaneously, considering the uncertainty of the satellite signal propagation path and delay jitter, the window duration also needs to be increased accordingly to cover possible delay fluctuations. The extended random access response window parameters include a new start time offset and a new duration, both of which are recorded for later use.

[0077] It should be noted that the window expansion is not unlimited. An excessively long window will cause the terminal receiver to remain in listening mode for an extended period, increasing power consumption and reducing its ability to suppress interference signals. The satellite communication module 102 sets an upper limit when expanding the window to ensure that the window length is within a reasonable range.

[0078] 304. The received signal is frequency offset estimated by the satellite communication module to obtain the Doppler frequency offset value, and the frequency of the transmitted signal is compensated according to the Doppler frequency offset value to obtain the frequency compensation parameter; In this embodiment, the satellite communication module 102 estimates the frequency offset by analyzing the received satellite downlink signal. The satellite periodically broadcasts synchronization signals or pilot signals, which contain known frequency components. The receiver of the satellite communication module 102 performs spectrum analysis on the downlink signal, extracts the pilot carrier or synchronization sequence, and measures its actual received frequency.

[0079] The actual received frequency is compared with the nominal frequency specified in the protocol; the difference between the two is the downlink signal frequency offset. This frequency offset includes the combined effects of several factors: the frequency error of the satellite local oscillator, the frequency error of the terminal local oscillator, and the frequency shift caused by the Doppler effect. Among these, the local oscillator frequency error can be controlled within a small range through crystal oscillator calibration, while the main source of frequency offset is the Doppler effect.

[0080] Although GEO satellites remain relatively stationary relative to the ground, their orbits are not entirely stationary, exhibiting slight east-west and north-south drift. Furthermore, satellite orbit-maintaining maneuvers generate brief velocity components. The movement of the terminal itself also produces the Doppler effect, particularly in vehicle-mounted or airborne applications. These relative movements cause frequency shifts in the received signal.

[0081] The satellite communication module 102 identifies the measured frequency offset value as the Doppler frequency offset value. Due to the symmetry of the Doppler effect, the frequency offset of the downlink signal is numerically similar to that of the uplink signal but in opposite directions. If the downlink signal frequency is higher than the nominal value, it indicates a tendency for the satellite and the terminal to move closer together, and the uplink signal will also generate a positive frequency offset when received by the satellite.

[0082] To compensate for the impact of uplink Doppler frequency offset on satellite reception, the satellite communication module 102 needs to pre-compensate the transmitted signal. The compensation principle is to adjust the frequency of the uplink signal transmitted by the terminal in the opposite direction to the nominal value, so that after the Doppler effect, the frequency of the signal received by the satellite is as close as possible to the nominal value. Specifically, if a positive downlink frequency offset is detected, the uplink transmission frequency should be reduced by a corresponding amount; if a negative downlink frequency offset is detected, the uplink transmission frequency should be increased.

[0083] The frequency compensation parameter is the adjustment amount for this pre-compensation, usually expressed in Hz or ppm. The satellite communication module 102 applies this parameter to the local oscillator frequency synthesizer to adjust the actual frequency of the uplink transmit carrier. The compensated transmit frequency ensures that the uplink signal can be accurately demodulated by the satellite receiver, avoiding demodulation failure due to excessive frequency offset.

[0084] In one specific embodiment, the satellite communication module 102 further filters the frequency offset estimation result to reduce the impact of instantaneous measurement noise. By averaging multiple consecutive measurements or using a low-pass filtering algorithm, a more stable frequency offset estimate can be obtained, making the frequency compensation parameters more reliable.

[0085] 305. The authentication key, the extended random access response window parameters, and the frequency compensation parameters are encapsulated by the satellite communication module to obtain the attach request message; In this embodiment, the satellite communication module 102 integrates and encapsulates the parameters acquired and calculated in the aforementioned steps. The encapsulation of the attach request message follows the message format defined by the NB-IoT NTN protocol, with different parameters placed in the corresponding fields of the message.

[0086] The encapsulation of authentication key-related information must adhere to security requirements. The authentication key Ki itself will not appear in plaintext in the message; instead, it will be processed using a cryptographic algorithm to generate an authentication response value. The satellite communication module 102 obtains a random number RAND from the system information broadcast by the satellite and calculates the authentication response value SRES using the A3 algorithm in the SIM card and the authentication key Ki. This SRES value is filled into the authentication field of the attach request message to prove to the network that the terminal holds a valid subscription certificate. Simultaneously, the message must also include the terminal's identification identifier, such as the International Mobile Subscriber Identity (IMSI) or the Temporary Mobile Subscriber Identity (TMSI).

[0087] The extended random access response window parameters are encoded as a timing configuration field in the message. This field indicates the start time and duration of the receive window that the terminal will use, enabling the satellite-side network equipment to understand the terminal's receive timing arrangements. Although this parameter is primarily used for receive control on the terminal side, in some protocol implementations, the network side also needs to know the terminal's window configuration in order to reasonably schedule the transmission time of the response message.

[0088] Frequency compensation parameters also need to be reflected in the message. This parameter can be directly entered into a dedicated field as a frequency offset, or it can be indicated to the network-side terminal via a capability indicator that frequency pre-compensation has been performed. In the latter case, the network device will consider the compensation already performed by the terminal when receiving uplink signals and adjust the receiver's frequency tracking strategy accordingly.

[0089] In addition to the core parameters mentioned above, the attach request message also contains other auxiliary information, such as the terminal's capability level, a list of supported frequency bands, and the type of service requested. This information helps the network side understand the terminal's functional characteristics in order to allocate resources and configure parameters appropriately.

[0090] Satellite communication module 102 fills the parameters into the message structure sequentially according to the field order and encoding rules specified in the protocol. The message header contains the message type identifier and length information, the message body contains the parameter fields, and the message tail may contain a checksum for error detection. The encapsulated attach request message forms a complete data packet, ready for transmission.

[0091] The data packet is sent to the protocol stack of the satellite communication module 102 for layer-by-layer processing. At the physical layer, the data packet undergoes channel coding to increase redundancy and improve anti-interference capability; it is then modulated and mapped to physical symbols; and the transmission power is adjusted by power control. At the radio frequency layer, the baseband signal is up-converted to the satellite communication frequency band, amplified by a power amplifier, and fed into the antenna system 104, ultimately radiating into space in the form of electromagnetic waves and propagating to the GEO satellite.

[0092] 306. The main processor performs character counting and processing on the original SMS content input by the user to obtain an SMS to be sent, and sends the SMS to be sent to the satellite communication module through the control link. The satellite communication module encapsulates the SMS to be sent to obtain a data packet, and sends the data packet to the satellite through the antenna system.

[0093] In this embodiment, the satellite communication module is activated when there is no cellular network signal coverage by detecting the cellular network signal status; the second SIM card switching circuit is controlled to enable the satellite communication module to read the satellite-specific SIM card and obtain the authentication key; an attach request message is generated and sent; the SMS content is processed, encapsulated, and sent to the satellite. This invention achieves intelligent management of cellular and satellite communication authentication through a dual SIM card switching circuit design, eliminating the need for manual SIM card insertion and removal.

[0094] The satellite communication method for mobile terminal devices in this embodiment of the invention has been described above. The server component quality inspection device in this embodiment of the invention is described below. Please refer to [link to relevant documentation] for details regarding this server component quality inspection device. Figure 4One embodiment of the server component quality inspection device in this invention includes: The signal detection module 401 is used to detect the signal status of the cellular network through the main processor, determine whether there is cellular network coverage based on the signal status, and when the determination result is that there is no cellular network coverage, the main processor sends a wake-up command to the satellite communication module. The card slot switching module 402 is used to control the second SIM card switching circuit to switch to the second input terminal through the main processor, so that the SIM interface of the satellite communication module is connected to the second SIM interface of the main processor. The satellite communication module reads the satellite-specific SIM card in the second SIM card slot through the second SIM card switching circuit to obtain the authentication key. The attach request module 403 is used to generate an attach request message based on the authentication key through the satellite communication module, send the attach request message to the satellite through the antenna system, and obtain an attach accept message from the satellite. The SMS sending module 404 is used to count and process the character count of the original SMS content input by the user through the main processor to obtain the SMS to be sent, and send the SMS to be sent to the satellite communication module through the control link. The satellite communication module encapsulates the SMS to be sent to obtain a data packet, and sends the data packet to the satellite through the antenna system.

[0095] In this embodiment of the invention, the server component quality inspection device operates the satellite communication method of the aforementioned mobile terminal device. The device obtains multiple sets of performance test data by performing tiered benchmark tests on the AI ​​server to be tested. Based on each set of performance test data, it calculates the cumulative distribution to obtain multiple test cumulative distribution curves. It then calculates the distribution distance between the test cumulative distribution curves and the preset baseline cumulative distribution curve to obtain multiple distribution distance values. Finally, it determines whether the server is qualified by comparing the distribution distance values ​​with a preset threshold. This invention uses cumulative distribution curves to characterize the overall distribution characteristics of performance data and quantifies the deviation of test results from the baseline through distribution distance. This effectively identifies problematic devices with large performance fluctuations and poor stability, improving the accuracy and reliability of AI server quality inspection.

[0096] The present invention also provides a computer-readable storage medium, which can be a non-volatile computer-readable storage medium or a volatile computer-readable storage medium, wherein the computer-readable storage medium stores instructions that, when executed on a computer, cause the computer to perform the steps of the satellite communication method of the mobile terminal device.

[0097] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the system, device, or unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0098] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0099] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A mobile terminal device, characterized in that, The mobile terminal device includes: The main processor has a first SIM interface and a second SIM interface, used to process cellular communication protocols and satellite communication control commands; The satellite communication module is connected to the main processor via a control link and is used to establish a communication link with the satellite and perform data transmission and reception. A SIM card management circuit is used to manage the SIM card switching of the mobile terminal device. The SIM card management circuit includes a first SIM card switching circuit and a second SIM card switching circuit. The input terminal of the first SIM card switching circuit is connected to the first SIM card slot and the eSIM chip respectively, and the output terminal is connected to the first SIM interface of the main processor, which is used to switch between the physical SIM card and the embedded SIM. The first input terminal of the second SIM card switching circuit is connected to the second SIM card slot, the second input terminal is connected to the SIM interface of the satellite communication module, and the output terminal is connected to the second SIM interface of the main processor, which is used to switch between the cellular SIM card and the satellite communication module; The antenna system, connected to the main processor and satellite communication module, is used to transmit and receive radio frequency signals.

2. The mobile terminal device according to claim 1, characterized in that, The mobile terminal device also includes an audio switch, the first input of which is connected to the audio output of the main processor, the second input of which is connected to the audio output of the satellite communication module, and the output is connected to a microphone.

3. A satellite communication method applied to a mobile terminal device as described in claim 1 or 2, characterized in that, The satellite communication method includes: The main processor detects the signal status of the cellular network and determines whether there is cellular network coverage based on the signal status. When the determination result is that there is no cellular network coverage, the main processor sends a wake-up command to the satellite communication module. The main processor controls the second SIM card switching circuit to switch to the second input terminal, so that the SIM interface of the satellite communication module is connected to the second SIM interface of the main processor. The satellite communication module reads the satellite-specific SIM card in the second SIM card slot through the second SIM card switching circuit to obtain the authentication key. The satellite communication module generates an attach request message based on the authentication key, and sends the attach request message to the satellite through the antenna system to obtain an attach accept message from the satellite. The main processor counts and processes the original SMS content input by the user to obtain the SMS to be sent, and sends the SMS to be sent to the satellite communication module through the control link. The satellite communication module encapsulates the SMS to be sent to obtain a data packet, and sends the data packet to the satellite through the antenna system.

4. The satellite communication method for a mobile terminal device according to claim 3, characterized in that, After transmitting the data packet to the satellite via the antenna system, the method further includes: When a user initiates a satellite voice call request, the main processor controls the audio switch to switch to the second input terminal, so that the microphone is connected to the audio output terminal of the satellite communication module. The microphone collects audio signals and inputs them into the satellite communication module for audio processing to obtain processed audio data. The processed audio data is encapsulated into voice data packets by the satellite communication module, and then transmitted to the satellite via the antenna system.

5. The satellite communication method for a mobile terminal device according to claim 3, characterized in that, The step of detecting the signal status of the cellular network through the main processor and determining whether cellular network coverage exists based on the signal status includes: The main processor reads the Received Signal Strength Indicator (RSSI) value of the cellular network. The received signal strength indicator (RSSI) value is compared with a preset threshold, and the duration of the RSSI value being lower than the preset threshold is recorded to obtain the duration of signal weakening. When the duration of signal weakening exceeds a preset duration, it is determined that there is no cellular network coverage.

6. The satellite communication method for a mobile terminal device according to claim 3, characterized in that, The step of generating an attach request message via the satellite communication module based on the authentication key includes: The satellite communication module calculates the round-trip time of the signal based on the orbital altitude of the GEO satellite, and expands the random access response window based on the round-trip time of the signal to obtain the expanded random access response window; The satellite communication module estimates the frequency offset of the received signal to obtain the Doppler frequency offset value, and compensates the frequency of the transmitted signal based on the Doppler frequency offset value to obtain the frequency compensation parameter. The satellite communication module encapsulates the authentication key, the extended random access response window parameters, and the frequency compensation parameters to obtain the attach request message.

7. The satellite communication method for a mobile terminal device according to claim 6, characterized in that, The step of generating the attach request message based on the authentication key via the satellite communication module further includes: The satellite communication module calculates the distance between the satellite and the terminal based on the orbital altitude of the GEO satellite and the terminal position, and calculates the signal propagation delay based on the distance and the electromagnetic wave propagation speed to obtain the initial timing advance. The satellite communication module receives the synchronization signal from the satellite, measures the actual round-trip time delay, compares the actual round-trip time delay with the theoretical signal propagation delay, and obtains the delay deviation value. The initial timing advance is adjusted based on the delay deviation value to obtain the adjusted timing advance, and the timing advance is encapsulated in the attach request message.

8. The satellite communication method for a mobile terminal device according to claim 3, characterized in that, After receiving the attachment acceptance message from the satellite, the process also includes: The satellite communication module sends a link test data packet to the satellite and records the sending time to obtain the first timestamp; Receive the link test response data packet from the satellite and record the reception time to obtain the second timestamp; The actual round-trip time delay (RTD) is calculated based on the first timestamp and the second timestamp, and compared with the theoretical round-trip time delay calculated based on the orbital altitude of the GEO satellite to obtain the delay deviation value. When the delay deviation value exceeds the preset deviation threshold, the extended random access response window parameters and frequency compensation parameters are recalculated based on the delay deviation value to obtain the updated communication parameters. The updated communication parameters are applied to subsequent data transmissions via the satellite communication module.

9. A satellite communication device applied to a mobile terminal device as described in claim 1 or 2, characterized in that, The satellite communication device includes: The signal detection module is used to detect the signal status of the cellular network through the main processor, determine whether there is cellular network coverage based on the signal status, and when the determination result is that there is no cellular network coverage, the main processor sends a wake-up command to the satellite communication module. The card slot switching module is used to control the second SIM card switching circuit to switch to the second input terminal through the main processor, so that the SIM interface of the satellite communication module is connected to the second SIM interface of the main processor. The satellite communication module reads the satellite-specific SIM card in the second SIM card slot through the second SIM card switching circuit to obtain the authentication key. An attach request module is used to generate an attach request message based on the authentication key through the satellite communication module, send the attach request message to the satellite through the antenna system, and obtain an attach accept message from the satellite. The SMS sending module is used to count and process the character count of the original SMS content input by the user through the main processor to obtain the SMS to be sent, and to send the SMS to be sent to the satellite communication module through the control link. The satellite communication module encapsulates the SMS to be sent to obtain a data packet, and sends the data packet to the satellite through the antenna system.

10. A computer-readable storage medium storing instructions thereon, characterized in that, When the instruction is executed by the processor, it implements the steps of the satellite communication method of the mobile terminal device as described in any one of claims 3-8.

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