Downlink channel quality reporting method for satellite mobile communication

Abstract

The invention provides a satellite mobile communication downlink channel quality reporting method. In a low-orbit narrowband satellite mobile communication system, when the number of data verification failures in the process of analyzing a downlink data packet by a terminal side reaches a preset threshold value, the terminal side reports downlink channel quality to a network side, and active reporting of the downlink channel quality is realized; and when the terminal side receives the downlink data packet sent by the network side, obtaining the reporting indication from the header information of the downlink data packet, and reporting the downlink channel quality to the network side by the terminal side, thereby realizing passive reporting of the downlink channel quality.

Description

Technical Field

[0001] This application relates to the field of communications, and more particularly to a method for reporting downlink channel quality in satellite mobile communications. Background Technology

[0002] In low-Earth orbit narrowband satellite mobile communication, a frequency division full-duplex (FDM) mode is used. Uplink and downlink each have allocated bandwidth, and these frequency resources are further divided into N carriers, which are independent of each other. The network side can allocate one or more carriers to a terminal based on its rate requirements, and each carrier can transmit independent data packets. For data services with lower rate requirements, a single carrier resource can be configured for the terminal. However, for data services with higher rate requirements, the network side needs to configure multiple carrier resources for the terminal, a process known as carrier aggregation. The allocated carrier resources are not necessarily contiguous in the frequency domain and may be distributed across the entire bandwidth. This necessitates measuring the downlink channel quality for each downlink carrier and reporting it to the network side via the uplink channel.

[0003] In the current low-Earth orbit narrowband satellite mobile communication protocol, in the context of data services, there is no definition on how to trigger the reporting of downlink channel quality. Only a MAC CE for reporting downlink channel quality is defined. However, this MAC CE cannot distinguish between different carriers, and in the case of multi-carrier aggregation, it is not possible to report downlink channel quality for each downlink carrier. Summary of the Invention

[0004] The following is an overview of the topics described in detail in this article.

[0005] The purpose of this application is to at least partially solve one of the technical problems existing in the related technologies. The embodiments of this application provide a method for reporting downlink channel quality in satellite mobile communication.

[0006] An embodiment of this application discloses a downlink channel quality reporting method for satellite mobile communication, applied to low-Earth orbit narrowband satellite mobile communication. The method includes: When the number of data verification failures during the parsing of downlink data packets by the terminal reaches a preset threshold, the terminal actively reports the downlink channel quality to the network. When the terminal receives a downlink data packet sent by the network side, it obtains a reporting instruction from the header information of the downlink data packet and passively reports the downlink channel quality to the network side.

[0007] According to certain embodiments of this application, the downlink channel quality reporting information includes carrier indication information for distinguishing different downlink carriers.

[0008] According to certain embodiments of this application, before the terminal actively reports downlink channel quality to the network side, the method includes: The terminal receives downlink data packets from the downlink carrier. The terminal parses and verifies the downlink data packets to obtain a data verification result, which includes data verification success and data verification failure. The terminal side calculates the downlink carrier block error rate by statistically analyzing the data verification results. The terminal determines whether to trigger the reporting of the downlink channel quality of the corresponding downlink carrier to the network side based on the block bit error rate of the downlink carrier.

[0009] According to certain embodiments of this application, the block error rate is expressed as: BLER(n) = factor(n) * BLER(n-1) + (1 - factor(n)) * CRC(n); where BLER(n) is the estimated block error rate when the nth downlink data packet is received; CRC(n) is the data verification result value of the nth downlink data packet, where the data verification result value is 0 when the data verification is successful and 1 when the data verification fails; factor(n) is the forgetting factor when the nth downlink data packet is received, and factor(n) is expressed as: factor(n) = , This is the stable value of the forgetting factor.

[0010] According to certain embodiments of this application, the reporting instruction is stored in the command field of the MAC PDU header information of the downlink data packet, and the command field is configured from the reserved fields in the header information of the downlink data packet.

[0011] According to certain embodiments of this application, when the network side requests the terminal side to report downlink channel quality, the command field of the header information of the downlink data packet is configured to 1.

[0012] According to certain embodiments of this application, before the terminal passively reports downlink channel quality to the network side, the method includes: The terminal receives downlink data packets from the downlink carrier. The terminal reads the command field from the header information of the downlink data packet; The terminal side determines whether to trigger the reporting of the downlink channel quality of the corresponding downlink carrier to the network side based on the command field.

[0013] According to certain embodiments of this application, the downlink channel quality reporting information is in MAC CE format, and the reserved fields in the MAC CE format are configured as carrier indication fields, and the carrier indication information is stored in the carrier indication field.

[0014] According to certain embodiments of this application, the downlink carrier number is calculated from the carrier indication field, and the downlink carrier number is expressed as: Band id = (T%M)* max_BIDX_num + BIDX; where Band id is the downlink carrier number; T is the current system frame number; M is the minimum number of frames required to complete all channel quality reports, M=ceil(N / max_BIDX_num), ceil is the rounding up calculation, N is the number of downlink carriers, max_BIDX_num is the upper limit of the number of downlink carriers represented by the carrier indication field, and BIDX is the value of the carrier indication field.

[0015] According to certain embodiments of this application, the value range of the carrier indication field is 0 to 3.

[0016] The above scheme has at least the following beneficial effects: In the low-orbit narrowband satellite mobile communication system, when the number of data verification failures during the parsing of downlink data packets by the terminal side reaches a preset threshold, the terminal side reports the downlink channel quality to the network side, realizing active reporting of downlink channel quality; when the terminal side receives downlink data packets sent by the network side, obtains the reporting indication from the header information of the downlink data packets, and reports the downlink channel quality to the network side, realizing passive reporting of downlink channel quality; by configuring carrier indication information in the downlink channel quality reporting information to distinguish different downlink carriers, downlink channel quality reporting can be performed for each downlink carrier in multi-carrier aggregation scenarios. Attached Figure Description

[0017] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0018] Figure 1 This is a step diagram of the satellite mobile communication downlink channel quality reporting method; Figure 2 This is a flowchart illustrating the steps of the proactive reporting process; Figure 3 This is a flowchart of the passive reporting process; Figure 4 This is a flowchart of the terminal actively reporting downlink channel quality; Figure 5 This is a flowchart of the terminal side passively reporting downlink channel quality; Figure 6 This is a structural diagram of the original multiplexed downlink data MAC packet format; Figure 7 This is a structural diagram of the multiplexed downlink data MAC packet format according to an embodiment of this application; Figure 8This is a structural diagram of the original MAC CE format for reporting uplink and downlink channel quality; Figure 9 This is a structural diagram of the MAC CE format for reporting downlink channel quality according to an embodiment of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0020] It should be noted that although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first," "second," etc., in the specification, claims, or the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0021] In low-Earth orbit narrowband satellite mobile communication, a frequency division full-duplex (FDM) mode is used. Uplink and downlink each have allocated bandwidth, and these frequency resources are further divided into N carriers, which are independent of each other. The network side can allocate one or more carriers to a terminal based on its rate requirements, and each carrier can transmit independent data packets. For data services with lower rate requirements, a single carrier resource can be configured for the terminal. However, for data services with higher rate requirements, the network side needs to configure multiple carrier resources for the terminal, a process known as carrier aggregation. The allocated carrier resources are not necessarily contiguous in the frequency domain and may be distributed across the entire bandwidth. This necessitates measuring the downlink channel quality for each downlink carrier and reporting it to the network side via the uplink channel.

[0022] In the current protocol architecture, in the context of data services, there is no definition on how to trigger the reporting of downlink channel quality. Only a MAC CE for reporting downlink channel quality is defined. However, this MAC CE cannot distinguish between different carriers, and in the case of multi-carrier aggregation, it is not possible to report downlink channel quality for each downlink carrier.

[0023] In current low-Earth orbit narrowband mobile communication protocols, there is no scheme to trigger downlink channel quality reporting. Defining the triggering procedure for terminal-side downlink channel quality reporting and the reporting logic for different downlink carrier channels under multi-carrier aggregation service channels, and implementing a terminal downlink channel quality reporting mechanism in data service scenarios, has become an urgent problem to be solved.

[0024] To address the above issues, embodiments of this application provide a method for reporting downlink channel quality in satellite mobile communication, applicable to low-Earth orbit narrowband satellite mobile communication.

[0025] The embodiments of this application will be further described below with reference to the accompanying drawings.

[0026] Reference Figure 1 A method for reporting downlink channel quality in satellite mobile communication includes the following steps: Step S100: When the number of data verification failures during the parsing of downlink data packets by the terminal side reaches a preset threshold, the terminal side actively reports the downlink channel quality to the network side. In step S200, when the terminal receives the downlink data packet sent by the network side, it obtains the reporting instruction from the header information of the downlink data packet and passively reports the downlink channel quality to the network side.

[0027] The triggering process for terminal-side reporting downlink channel quality includes an active reporting process and a passive reporting process.

[0028] The proactive reporting process is as follows: when the number of data verification failures during the parsing of downlink data packets by the terminal reaches a preset threshold, the terminal proactively reports the downlink channel quality to the network side.

[0029] The passive reporting process is as follows: when the terminal receives the downlink data packet sent by the network side, it obtains the reporting instruction from the header information of the downlink data packet, and the terminal passively reports the downlink channel quality to the network side.

[0030] The following is a detailed description of the proactive reporting process.

[0031] Reference Figure 2 The proactive reporting process includes the following steps: Step S110: The terminal receives downlink data packets from the downlink carrier; Step S120: The terminal side parses and verifies the downlink data packet to obtain the data verification result; the data verification result includes data verification success and data verification failure. Step S130: The terminal side statistically verifies the results to obtain the block bit error rate of the downlink carrier; Step S140: The terminal side determines whether to trigger reporting of the downlink channel quality of the corresponding downlink carrier to the network side based on the block bit error rate of the downlink carrier. In step S150, when the block bit error rate of the downlink carrier reaches a preset threshold, the terminal actively reports the downlink channel quality to the network side.

[0032] Reference Figure 4For example, the network side sends downlink data packets to the terminal side via downlink carriers, and the terminal side receives downlink data packets from each downlink carrier. The terminal side parses the downlink data packets from each downlink carrier. The terminal side performs data verification on the downlink data packets from the downlink carriers, such as CRC (Cyclic Redundancy Check).

[0033] CRC check is a core error detection technology in the field of data communication. It generates a check code through polynomial modulo 2 division and verifies it at the receiving end. It can efficiently detect single-bit and burst errors in data transmission and is a key link in ensuring the integrity of downlink data in low-orbit narrowband satellite mobile communication.

[0034] Both communicating parties agree on a unified generator polynomial, whose most significant and least significant bits must be 1. The network side appends 0s to the highest power number of the generator polynomial to the end of the original data. It then performs a modulo-2 division (without borrowing, only XOR operation) with the generator polynomial, and the remainder is the CRC checksum (one less bit than the generator polynomial). This checksum is appended to the original data to form a new transmission frame, which is then sent as a downlink data packet. The terminal side repeats the modulo-2 division operation on the entire frame. If the remainder is 0, the data is complete; otherwise, it is considered corrupted, triggering a retransmission or data discard mechanism.

[0035] The terminal performs CRC checks on downlink data packets to obtain the data verification result. The data verification result includes data verification success and data verification failure. Data verification success is recorded as ACK, and data verification failure is recorded as NACK.

[0036] The forgetting factor filtering algorithm module is invoked to estimate the bit error rate (BLER) of each downlink carrier based on the data verification results.

[0037] The forgetting factor filtering algorithm is as follows. The block error rate is expressed as: BLER(n) = factor(n) * BLER(n-1) + (1-factor(n)) * CRC(n); where BLER(n) is the estimated block error rate when the nth downlink data packet is received; CRC(n) is the data verification result value of the nth downlink data packet, where the data verification result value is 0 when the data verification is successful and 1 when the data verification fails; factor(n) is the forgetting factor when the nth downlink data packet is received, expressed as: factor(n) = , This is the stable value of the forgetting factor, which is a constant value.

[0038] The bit error rate (BER) reflects the number of data verification failures. The system checks if the BER is greater than or equal to a preset threshold, `bler_threshhold`, which indicates that the number of data verification failures has reached the preset threshold. If the BER is greater than or equal to `bler_threshhold`, downlink channel quality reporting for the corresponding downlink carrier is triggered, while downlink data reception continues; if the BER is less than `bler_threshhold`, downlink data reception continues.

[0039] The process of passively reporting downlink channel quality by the terminal side, initiated by the network side, is mainly used during the initial establishment of data services.

[0040] Reference Figure 3 The passive reporting process includes the following steps: Step S210: The terminal receives downlink data packets from the downlink carrier. Step S220: The terminal reads the command field from the header information of the downlink data packet; Step S230: The terminal side determines whether to trigger the reporting of the downlink channel quality of the corresponding downlink carrier to the network side based on the command field; In step S240, when the terminal side determines the reporting instruction from the command field of the header information of the downlink data packet, the terminal side passively reports the downlink channel quality to the network side.

[0041] Reference Figure 5 For example, the reporting instruction is stored in the command field of the MAC PDU header information of the downlink data packet, and the command field is configured by the reserved fields in the header information of the downlink data packet.

[0042] Reference Figure 6 In the original multiplexed downlink data MAC packet format, the first byte includes the SRNTI field and the MCS_1 field, the second byte includes the MCS_2 field, the L field, the EI field, the R field and the Payload_1 field, and the third to nth fields are the Payload_2 field.

[0043] In this satellite mobile communication downlink channel quality reporting method, a 1-bit reserved field (R field) in the header information of the downlink data MAC packet is reused and configured as a command field (C field).

[0044] Reference Figure 7 In the multiplexed downlink data MAC packet format of the satellite mobile communication downlink channel quality reporting method, the first byte includes the SRNTI field and the MCS_1 field, the second byte includes the MCS_2 field, the L field, the EI field, the C field and the Payload_1 field, and the third to nth fields are the Payload_2 field.

[0045] When the network side requests the terminal side to report downlink channel quality, the command field of the downlink data packet header is configured to 1.

[0046] The terminal receives downlink data packets from the downlink carrier; the terminal reads the command field from the header information of the downlink data packet; the terminal determines whether to trigger the reporting of the downlink channel quality of the corresponding downlink carrier to the network side based on the command field. When the command field is 1, the terminal determines the reporting indication, and the terminal passively reports all downlink channel quality to the network side.

[0047] The problem of distinguishing between different downlink channels in the reported MAC CE is solved by setting carrier indication information to differentiate between different downlink carriers in the downlink channel quality reporting information.

[0048] Reference Figure 8 The original MAC CE format for reporting uplink and downlink channel quality in the low-orbit narrowband satellite mobile communication protocol is as follows: the first byte includes a 2-bit R field, a 1-bit E field, and a 5-bit LCID field, and the second byte includes the channel quality value.

[0049] As can be seen from this MAC CE, there is no field indicating downlink carrier information, and the network side cannot distinguish which downlink carrier's channel quality report is being reported based on this MAC CE.

[0050] Reference Figure 9 In this satellite mobile communication downlink channel quality reporting method, the 2-bit reserved field that was not used in the original MAC CE format is configured as the BIDX field, which stands for band index and is a carrier indicator.

[0051] Therefore, the MAC CE format for reporting downlink channel quality using this satellite mobile communication downlink channel quality reporting method is as follows: the first byte includes a 2-bit BIDX field, a 1-bit E field, and a 5-bit LCID field, and the second byte includes the channel quality value.

[0052] The carrier indication field, combined with the system frame number, is used to indicate the downlink carrier as follows: When configuring downlink service channels for terminals, the network side configures the number of downlink carriers as band_num, with the initial value of the configured carrier numbers starting from 0. For example, when configuring downlink N-carrier aggregation, the band_num carrier numbers are 0, 1, 2, ..., N-1 respectively; The current system frame number is T; The number of bits in the BIDX field is bits_num, and the upper limit of the number of carriers that the BIDX field can distinguish is: max_BIDX_num = When bits_num is 2 bits, max_BIDX_num = 4; The minimum number of frames required to complete all channel quality reports is M = ceil(N / max_BIDX_num), which means that the value of M is the number of downlink carrier channels divided by BIDX_num and rounded up. The formula for calculating the downlink carrier number (band id) indicated by the MAC CE is as follows: Band id = (T%M)* max_BIDX_num + BIDX.

[0053] Understandably, the downlink carrier number is represented as: Band id = (T%M)* max_BIDX_num +BIDX; where Band id is the downlink carrier number; T is the current system frame number; M is the minimum number of frames required to complete all channel quality reports, M=ceil(N / max_BIDX_num), ceil is the rounding up calculation, N is the number of downlink carriers, max_BIDX_num is the upper limit of the number of downlink carriers represented by the carrier indication field, and BIDX is the value of the carrier indication field.

[0054] This indication method enables channel quality indication for each downlink channel under multi-carrier aggregation, completing the channel quality indication for all downlink channels within M frames. For example, in a 16-carrier aggregation scenario of low-Earth orbit narrowband mobile communication, the downlink channel quality of all 16 carriers can be reported within 4 frames.

[0055] The embodiments of this application provide a low-Earth orbit narrowband satellite communication system that applies the satellite mobile communication downlink channel quality reporting method described above.

[0056] When the number of data verification failures during the parsing of downlink data packets reaches a preset threshold, the terminal reports the downlink channel quality to the network side, realizing active reporting of downlink channel quality. When the terminal receives downlink data packets sent by the network side and obtains a reporting instruction from the header information of the downlink data packets, the terminal reports the downlink channel quality to the network side, realizing passive reporting of downlink channel quality. By configuring carrier indication information in the downlink channel quality reporting information to distinguish different downlink carriers, downlink channel quality reporting can be performed for each downlink carrier in multi-carrier aggregation scenarios.

[0057] Low Earth Orbit (LEO) narrowband satellite communication systems are narrowband satellite constellations operating in low Earth orbit, with UHF / VHF, L, and S frequency bands as their core operating frequencies. The system mainly consists of three parts: a space segment, a ground segment, and a user segment. It features low power consumption, low cost, and wide coverage, and is widely used in scenarios such as the Internet of Things (IoT), emergency communications, and data transmission in remote areas.

[0058] For the space segment (i.e., the network side), the core is a low-Earth orbit (LEO) narrowband satellite constellation, consisting of dozens to hundreds of LEO satellites, achieving global coverage through constellation networking. Data transmission is achieved through FDMA (Fixed-DMA Multiple Access) technology. Each satellite carries a narrowband communication payload and an inter-satellite link module, enabling data reception, forwarding, and basic onboard processing.

[0059] The ground segment includes ground gateway stations, telemetry, tracking, and command (TT&C) centers, and operations support platforms. Gateway stations are responsible for enabling interconnection between the satellite and the ground network, and for completing data protocol conversion and distribution; the TT&C center monitors and adjusts the satellite's orbit and attitude; and the operations support platform manages user terminals, billing, and service scheduling.

[0060] For the user segment (i.e., the terminal side), the focus is on low-power, miniaturized narrowband terminals, including IoT sensors, satellite phones, and emergency terminals. These terminals support short message transmission, positioning, and other functions, and are compatible with consumer products such as mobile phones and wearable devices, as well as various industrial applications.

[0061] Low-Earth orbit (LEO) narrowband satellite communication systems operate in narrowband frequencies, primarily UHF / VHF and L / S bands, with bandwidth typically within 10MHz and transmission rates around 1.6Mbps. They are primarily designed for small data transmissions, providing services such as voice, SMS, and low-speed data services, while also balancing low power consumption and wide coverage. Operating at altitudes of 200-2000km, compared to high-Earth orbit (HEO) satellites, they offer transmission latency of only 20 to 100 milliseconds and lower link loss, allowing for miniaturization of terminal devices and even integration into mobile phone chips. Commonly used narrowband multiple access technologies include FDMA, TDMA, and CDMA, adapting to the access needs of massive numbers of IoT terminals and enabling direct satellite connection for voice, SMS, and low-speed data services.

[0062] Embodiments of this application provide a computer storage medium. The computer storage medium stores computer-executable instructions for executing the satellite mobile communication downlink channel quality reporting method described above.

[0063] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, it is well known to those skilled in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium. In the foregoing description of this specification, references to terms such as "one embodiment," "another embodiment," or "some embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0064] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0065] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0066] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0067] 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 this application, 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 multiple 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 of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0068] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed between each other may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms. Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

[0069] The above is a detailed description of the preferred embodiments of this application, but this application is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this application, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A method for reporting downlink channel quality in satellite mobile communication, characterized in that, The method, applied to low-Earth orbit narrowband satellite mobile communications, includes: When the number of data verification failures during the parsing of downlink data packets by the terminal reaches a preset threshold, the terminal actively reports the downlink channel quality to the network. When the terminal receives a downlink data packet sent by the network side, it obtains a reporting instruction from the header information of the downlink data packet and passively reports the downlink channel quality to the network side.

2. The satellite mobile communication downlink channel quality reporting method according to claim 1, characterized in that, The downlink channel quality reporting information includes carrier indication information used to distinguish different downlink carriers.

3. The satellite mobile communication downlink channel quality reporting method according to claim 1, characterized in that, Before the terminal actively reports the downlink channel quality to the network, the method includes: The terminal receives downlink data packets from the downlink carrier. The terminal parses and verifies the downlink data packets to obtain a data verification result, which includes data verification success and data verification failure. The terminal side calculates the downlink carrier block error rate by statistically analyzing the data verification results. The terminal determines whether to trigger the reporting of the downlink channel quality of the corresponding downlink carrier to the network side based on the block bit error rate of the downlink carrier.

4. The satellite mobile communication downlink channel quality reporting method according to claim 3, characterized in that, The block error rate is expressed as: BLER(n) = factor(n) * BLER(n-1) + (1 - factor(n)) * CRC(n); where BLER(n) is the estimated block error rate when the nth downlink data packet is received; CRC(n) is the data verification result value of the nth downlink data packet. A successful verification result is 0, and a failed verification result is 1. factor(n) is the forgetting factor when the nth downlink data packet is received, expressed as: factor(n) = , This is the stable value of the forgetting factor.

5. The satellite mobile communication downlink channel quality reporting method according to claim 1, characterized in that, The reporting instruction is stored in the command field of the MAC PDU header information of the downlink data packet, and the command field is configured by the reserved fields in the header information of the downlink data packet.

6. The satellite mobile communication downlink channel quality reporting method according to claim 5, characterized in that, When the network side requests the terminal side to report downlink channel quality, the command field of the header information of the downlink data packet is configured to 1.

7. The satellite mobile communication downlink channel quality reporting method according to claim 6, characterized in that, Before the terminal passively reports downlink channel quality to the network, the method includes: The terminal receives downlink data packets from the downlink carrier. The terminal reads the command field from the header information of the downlink data packet; The terminal side determines whether to trigger the reporting of the downlink channel quality of the corresponding downlink carrier to the network side based on the command field.

8. The satellite mobile communication downlink channel quality reporting method according to claim 2, characterized in that, The downlink channel quality reporting information is in MAC CE format, and the reserved fields in the MAC CE format are configured as carrier indication fields, and the carrier indication information is stored in the carrier indication field.

9. The satellite mobile communication downlink channel quality reporting method according to claim 8, characterized in that, The downlink carrier number is calculated from the carrier indication field. The downlink carrier number is represented as: Band id = (T%M)* max_BIDX_num + BIDX; where Band id is the downlink carrier number; T is the current system frame number; M is the minimum number of frames required to complete all channel quality reports, M=ceil(N / max_BIDX_num), ceil is the rounding up calculation, N is the number of downlink carriers, max_BIDX_num is the upper limit of the number of downlink carriers represented by the carrier indication field, and BIDX is the value of the carrier indication field.

10. The satellite mobile communication downlink channel quality reporting method according to claim 9, characterized in that, The value range of the carrier indication field is 0 to 3.

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