A method, system and related device for controlling outbound transmission in a satellite communication system

Abstract

A method, system and related apparatus for controlling outbound transmission in a satellite communication system. In this method, the Beidou network device splits the application layer message into multiple MDCP PDUs at the MDCP layer. The Beidou network device sequentially sends the MDCP PDUs to the SLC layer as the SLC SDUs of the SLC layer, and splits the SLC SDUs into N SLC PDUs at the SLC layer. The PHY layer obtains the SLC PDUs of one or more users from the SLC layer. The PHY will splice the SLC PDUs of multiple users or one user together to form outbound data of a physical time slot of a fixed length. Ultimately, the Beidou network device sends the outbound data to one or more terminals. By implementing the technical solution provided in this application, the Beidou network device can realize multi-frame transmission, meet the outbound data requirements of different business types, optimize the outbound resource configuration, and improve the outbound resource utilization.

Description

Technical Field

[0001] The present application relates to the field of satellite communication technology, and in particular to an outbound transmission control method, system and related devices in a satellite communication system. Background Art

[0002] The Beidou satellite navigation system is a major infrastructure integrating positioning, timing, and communications. Beidou's short message communication service is a key feature that distinguishes it from other global navigation systems, including the US GPS, Russia's GLONASS, and Europe's GALILEO. It is particularly suitable for communication in areas such as oceans, deserts, grasslands, and uninhabited areas where mobile communications are not available, cannot be reached, or where communications systems are disrupted. The Beidou-3 satellite communication system features an upgraded short message technology architecture. To address the specific needs of civilian services and equipment, a communication protocol designed specifically for the Beidou communication system is required.

[0003] Due to the limited civilian resources available in the BeiDou communication system, the current transmission capabilities of BeiDou equipment are also limited, resulting in low outbound data capacity in the BeiDou communication system. Therefore, how to achieve reliable and efficient transmission of outbound services within the constraints of low outbound data capacity is an urgent problem to be solved. Summary of the Invention

[0004] The present application provides an outbound transmission control method, system and related devices in a satellite communication system. Through the method provided in the embodiments of the present application, reliable and effective transmission of outbound services can be achieved under the limitation of low outbound data capacity.

[0005] In a first aspect, the present application provides an outbound transmission control method in a satellite communication system, which may include: a Beidou network device generates a first user frame sent to a first terminal and a second user frame sent to a second terminal at the satellite link control SLC layer; wherein the frame header information of the first user frame includes a first user ID field and a first frame type field; the first user ID field is used to indicate the terminal receiving the first user frame; the first user ID field contains the ID information of the first terminal; the first frame type field is used to indicate the frame type of the first user frame; the frame header information of the second user frame includes a second user ID field and a second frame type field; the second user ID field is used to indicate the terminal receiving the second user frame; the second user ID field contains the ID information of the second terminal; the second frame type field is used to indicate the frame type of the second user frame; the Beidou network device generates a first physical frame based on the first user frame and the second user frame at the physical PHY layer; and the Beidou network device sends the first physical frame.

[0006] The first user frame includes a satellite link control layer protocol data unit (SLC PDU), an acknowledgment character (ACK) frame, and an application layer receipt frame. The SLC PDU can be used to transmit data, and the acknowledgment character (ACK) frame can be used to indicate whether the Beidou network device has successfully received the terminal's SLC PDU. The application layer receipt frame is used to indicate whether the Beidou network device has successfully parsed the received application layer message.

[0007] This allows BeiDou network equipment to simultaneously transmit user frames for multiple end users, enabling reliable and efficient transmission of outbound services within the constraints of low outbound data capacity. Furthermore, BeiDou network equipment can also transmit different types of user frames, thus meeting the needs of different outbound services.

[0008] In combination with the first aspect, in a possible implementation method, the first user frame is the first satellite link control layer protocol data unit SLC PDU in the first satellite link control layer service data unit SLC SDU, and the frame header information of the first user frame also includes an acknowledgment mode enable AM ​​enable field, a total number of frames field, and a frame sequence number field; wherein the AM enable field is used to indicate whether the first terminal replies ACK or not; the total number of frames field is used to indicate the number of SLC PDUs sent by the Beidou network device to the first terminal; and the frame sequence number field is used to indicate the sequence number of the SLC PDU sent by the Beidou network device.

[0009] The AM enable field of the first SLC PDU has a first value, which is used to indicate that the first terminal does not reply with an ACK. The AM enable field of the first SLC PDU has a second value, which is used to indicate that the first terminal replies with an ACK.

[0010] In this way, the device receiving the first SLC PDU can know whether an ACK reply is required through the frame header information, and does not need to know whether an ACK reply is required through a separate signaling interaction.

[0011] In combination with the first aspect, in a possible implementation method, the first user frame is the first SLC PDU. After the Beidou network device sends the first physical frame, the method also includes: the Beidou network device continues to send one or more SLC PDUs in the first SLC SDU; after the Beidou network device sends all SLC PDUs in the first SLC SDU, the Beidou network device receives a first ACK sent by the first terminal, and the first ACK is used to indicate that the first terminal successfully receives all SLC PDUs in the first SLC SDU.

[0012] In this way, the Beidou network device can know that the first terminal has successfully received the SLC SDU through the ACK replied by the first terminal. In this way, the Beidou network device continues to send the next SLC SDU.

[0013] In conjunction with the first aspect, in one possible implementation, the first user frame is a first SLC PDU. After the Beidou network device sends the first physical frame, the method further includes: after the Beidou network device completes sending the first SLC PDU, the Beidou network device receives a second ACK sent by the first terminal, the second ACK being used to indicate that the first terminal failed to successfully receive the first SLC PDU; and the Beidou network device allocates resources of one or more SLC PDUs in the first SLC SDU to one or more SLC PDUs in a second SDU sent to the second terminal. In this way, resources of the Beidou network device can be conserved and resource recycling can be achieved.

[0014] In combination with the first aspect, in a possible implementation method, the first user frame is the first SLC PDU. After the Beidou network device sends the first physical frame, the method also includes: the Beidou network device continues to send one or more SLC PDUs in the first SLC SDU; after the Beidou network device sends all SLC PDUs in the first SLC SDU, the Beidou network device receives a third ACK sent by the first terminal, and the third ACK indicates that the first terminal failed to successfully receive all SLC PDUs in the first SLC SDU.

[0015] In this way, the Beidou network device can determine the next operation based on the ACK replied by the first terminal, for example, end the current transmission.

[0016] In combination with the first aspect, in one possible implementation, the frame header information of the first physical frame includes a rate indication field or a version number field; wherein the rate indication field is used to indicate the transmission rate of the first physical frame; and the version number field is used to indicate the current version information of the first physical frame.

[0017] In this way, the device receiving the physical frame can learn the rate and version information of the physical frame.

[0018] In combination with the first aspect, in a possible implementation method, the first user frame is the first SLC PDU, and before the Beidou network device generates the first user frame sent to the first terminal and the second user frame sent to the second terminal at the satellite link control layer SLC, the method also includes: the Beidou network device obtains the message data aggregation MDCP layer of the Beidou network device at the satellite link control SLC layer, and multiple satellite link control layer service data units SLC SDUs are sent, wherein the multiple SLC SDUs include the first SLC SDU; the Beidou network device splits the first SLC SDU into N SLC PDUs at the SLC layer.

[0019] In combination with the first aspect, in a possible implementation method, before the Beidou network device obtains multiple SLC SDUs sent down by the MDCP layer of the Beidou network device at the SLC layer, the method also includes: the Beidou network device obtains the application layer message sent down by the application layer of the Beidou network device at the MDCP layer; the Beidou network device uses the application layer message as the MDCP SDU at the MDCP layer, and after adding padding data and a redundant length indication field to the MDCP SDU, splits it into multiple MDCP PDUs; wherein the redundant length indication field is used to indicate the data length of the padding data, the multiple MDCP PDUs include a first MDCP PDU, the header information of the first MDCP PDU includes a subsequent indication field, and the subsequent indication field is used to indicate the order of the first MDCP PDU in the multiple MDCP PDUs; the Beidou network device sends the multiple MDCP PDUs from the MDCP layer to the SLC layer as multiple SLC SDUs of the SLC layer.

[0020] In combination with the first aspect, in a possible implementation method, before the Beidou network device obtains the application layer message sent by the application layer of the Beidou network device at the MDCP layer, the method also includes: the Beidou network device obtains the original data; the Beidou network device compresses the original data at the application layer to obtain compressed data; the Beidou network device encrypts the compressed data at the application layer to obtain encrypted data; the Beidou network device adds message header information to the encrypted data header to obtain an application layer message; wherein the message header information includes a compression indication field and an encryption indication field, the compression indication field is used to indicate the compression algorithm used when compressing the original data, and the encryption indication field is used to indicate the encryption algorithm used when encrypting the compressed data.

[0021] In combination with the first aspect, in a possible implementation method, the Beidou network device splits the first SLC SDU into N SLC PDUs at the SLC layer, specifically including: the Beidou network device sends the first SLC PDU and the second SLC PDU among the N SLC PDUs to the PHY layer; the Beidou network device generates a first physical frame for the first SLC PDU and generates a second physical frame for the second SLC PDU at the PHY layer; the Beidou network device sends the first physical frame and the second physical frame.

[0022] In combination with the first aspect, in a possible implementation method, the Beidou network device sends the first physical frame, including: the Beidou network device adds first check bit information at the end of the first physical frame at the PHY layer, and encodes the first physical frame and the first check bit information to obtain first coded data; the Beidou network device modulates the first coded data and the first reserved field of the first coded data at the PHY layer to obtain first modulated data; the Beidou network device spreads the first modulated data at the PHY layer to obtain first spread spectrum modulated data; the Beidou network device sends the first spread spectrum modulated data and the first pilot information of the first spread spectrum modulated data at the PHY layer.

[0023] In combination with the first aspect, in a possible implementation, the method may also include: the Beidou network device determines the starting time of the ACK reception time window based on the time when the Beidou network device sends the last SLC PDU in the first SLC SDU, the processing delay from the first terminal receiving the last SLC PDU in the first SLC SDU to sending ACK, and the air interface propagation delay; the Beidou network device starts to receive ACK at the starting time of the ACK reception time window.

[0024] In this way, the Beidou network device can determine the starting time of receiving ACK.

[0025] In combination with the first aspect, in a possible implementation, the method may also include: the Beidou network device determines the end time of the ACK reception time window based on the time when the Beidou network device sends the last SLC PDU in the first SLC SDU, the processing delay from the first terminal receiving the last SLC PDU in the first SLC SDU to sending ACK, the time length of the ACK sent by the first terminal, and the air interface propagation delay; the Beidou network device stops receiving ACK at the end time of the ACK reception time window.

[0026] In this way, the Beidou network device can determine the end time of receiving ACK.

[0027] In a second aspect, a method for controlling outbound transmission in a satellite communication system is provided, which may include: a first terminal receiving a first physical frame sent by a Beidou network device; the first physical frame includes a first user frame sent to the first terminal and a second user frame sent to the second terminal, wherein the frame header information of the first user frame includes a first user ID field and a first frame type field; the first user ID field is used to indicate the terminal receiving the first user frame; the first user ID field includes the ID information of the first terminal; the first terminal parses the first user frame from the first physical frame and discards the second user frame.

[0028] The first user frame includes a satellite link control layer protocol data unit (SLC PDU), an acknowledgment character (ACK) frame, and an application layer receipt frame. The SLC PDU can be used to transmit data, and the acknowledgment character (ACK) frame can be used to indicate whether the Beidou network device has successfully received the terminal's SLC PDU. The application layer receipt frame is used to indicate whether the Beidou network device has successfully parsed the received application layer message.

[0029] In this way, Beidou network devices can simultaneously transmit user frames for multiple terminal users, enabling reliable and efficient transmission of outbound services within the constraints of low outbound data capacity. Furthermore, Beidou network devices can also transmit different types of user frames. This eliminates the need to meet the needs of different outbound services. The first terminal can also receive different types of user frames.

[0030] In combination with the second aspect, in a possible implementation method, the first user frame is the first satellite link control layer protocol data unit SLC PDU in the first satellite link control layer service data unit SLC SDU, and the frame header information of the first user frame also includes an acknowledgment mode enable AM ​​enable field, a total number of frames field, and a frame sequence number field; wherein, the AM enable field is used to indicate whether the first terminal replies ACK or not; the total number of frames field is used to indicate the number of SLC PDUs sent by the Beidou network device to the first terminal; and the frame sequence number field is used to indicate the sequence number of the SLC PDU sent by the Beidou network device.

[0031] The AM enable field of the first SLC PDU has a first value, which is used to indicate that the first terminal does not reply with an ACK. The AM enable field of the first SLC PDU has a second value, which is used to indicate that the first terminal replies with an ACK.

[0032] In this way, the first terminal receiving the first SLC PDU can know whether an ACK reply is required through the frame header information, and does not need to know whether an ACK reply is required through a separate signaling interaction.

[0033] In combination with the second aspect, in a possible implementation, the first user frame is the first SLC PDU, the first terminal parses the first user frame from the first physical frame, and after discarding the second user frame, the method also includes: the first terminal receives one or more SLC PDUs in the first SLC SDU; when the first terminal receives all SLC PDUs in the first SLC SDU, the first terminal sends a first ACK to the Beidou network device, and the first ACK is used to indicate that the first terminal has successfully received all SLC PDUs in the first SLC SDU.

[0034] The value of the first ACK can be 1.

[0035] In combination with the second aspect, in a possible implementation, the first user frame is the first SLC PDU in the first SLC SDU, and the first terminal parses the first user frame from the first physical frame. After discarding the second user frame, the method also includes: when the first SLC PDU parsed by the first terminal is not the first SLC PDU in the first SLC SDU; the first terminal sends a second ACK to the Beidou network device and stops receiving the second SLC PDU in the first SLC SDU, and the second ACK is used to indicate that the first terminal failed to successfully receive the first SLC PDU.

[0036] In combination with the second aspect, in a possible implementation, the first user frame is the first SLC PDU in the first SLC SDU, and the first terminal parses the first user frame from the first physical frame, and after discarding the second user frame, the method also includes: the first terminal receives one or more SLC PDUs in the first SLC SDU; when the first terminal fails to receive all SLC PDUs in the first SLC SDU within the SLC PDU receiving time window, the first terminal sends a third ACK to the Beidou network device, and the third ACK is used to indicate that the first terminal has not successfully received all SLC PDUs in the first SLC SDU.

[0037] The values ​​of the second ACK and the third ACK can be 0.

[0038] In combination with the second aspect, in a possible implementation, the first user frame is the first SLC PDU in the first SLC SDU, and the first terminal parses the first user frame from the first physical frame and discards the second user frame, including: the first terminal obtains the first spread spectrum modulated data sent by the terminal at the PHY layer; the first terminal despreads the first spread spectrum modulated data at the PHY layer to obtain first modulated data and a first modulation synchronization header; the first terminal demodulates the first modulated data and the first modulation synchronization header at the PHY layer to obtain first pilot data and a first synchronization header; the first terminal removes the pilot information in the first pilot data at the PHY layer to obtain first coded data; the Beidou network device decodes the first coded data at the PHY layer to obtain a first coded block physical frame and first verification information; the first terminal verifies the first coded block based on the first verification information at the PHY layer, and after the verification is successful, presents the first user frame whose ID field in the first coded block is the same as the first terminal ID as the first SLC PDU in the first SLC SDU in the SLC layer of the first terminal from the PHY layer to the SLC layer of the first terminal.

[0039] In combination with the second aspect, in a possible implementation, the first terminal verifies the first coding block based on the first verification information at the PHY layer, and after the verification is successful, the first user frame in the first coding block whose ID field is the same as the first terminal ID is presented from the PHY layer to the SLC layer of the first terminal as the first SLC PDU in the first SLC SDU in the SLC layer of the first terminal. The method also includes: the first terminal splices the M received SLC PDUs into a first SLC SDU at the SLC layer, and reports the first SLC SDU as the first MDCP PDU of the MDCP layer from the SLC layer of the first terminal to the MDCP layer of the first terminal. The header information of the first MDCP PDU includes a successor indication field, and the successor indication field is used to indicate the order of the first MDCP PDU in the multiple MDCP PDUs sent by the Beidou network device.

[0040] In combination with the second aspect, in a possible implementation, the method also includes: the first terminal obtains a second MDCP PDU reported from the SLC layer of the first terminal at the MDCP layer; when the successor indication field in the second MDCP PDU indicates that the second MDCP PDU is the last one of multiple MDCP PDUs sent by the Beidou network device, the first terminal splices the first MDCP PDU and the second MDCP PDU into an MDCP SDU at the MDCP layer, and reports the MDCP SDU as an application layer message from the MDCP layer to the application layer.

[0041] In combination with the second aspect, in a possible implementation, the application layer message includes message header information and encrypted data, the message header information includes an encryption indication field and a compression indication field, the compression indication field is used to indicate the compression algorithm used by the terminal when compressing the original data into compressed data, and the encryption indication field is used to indicate the encryption algorithm used by the terminal when encrypting the compressed data into encrypted data; the method also includes: the first terminal decrypts the encrypted data in the application layer message at the application layer through the encryption algorithm indicated by the encryption indication field in the application layer message to obtain compressed data; the first terminal decompresses the compressed data at the application layer through the compression algorithm indicated by the compression indication field in the application layer message to obtain the original data.

[0042] In combination with the second aspect, in a possible implementation, the method also includes: the first terminal determines the time length of the SLC PDU receiving window in the first terminal based on the frame sequence number of the received SLC PDU, the time length of the SLC PDU sent by the Beidou network device, the total number of SLC PDU frames in an SLCSDU sent by the Beidou network device, and the sending interval between SLC PDUs.

[0043] In combination with the second aspect, in a possible implementation, the method also includes: the first terminal determines the time point when the first terminal sends the ACK based on the time length of the SLC PDU receiving window, the reception time of the first SLC PDU, the signal processing delay of the first terminal, and the time length of the ACK sent by the first terminal.

[0044] In a third aspect, a Beidou communication system is provided, including a Beidou network device and a first terminal, wherein:

[0045] The Beidou network device is used to generate a first user frame sent to a first terminal and a second user frame sent to a second terminal in a satellite link control layer SLC; wherein the frame header information of the first user frame includes a first user ID field and a first frame type field; the first user ID field is used to indicate a terminal receiving the first user frame; the first user ID field contains ID information of the first terminal; the first frame type field is used to indicate a frame type of the first user frame; the frame header information of the second user frame includes a second user ID field and a second frame type field; the second user ID field is used to indicate a terminal receiving the second user frame; the second user ID field contains ID information of the second terminal; and the second frame type field is used to indicate a frame type of the second user frame;

[0046] The Beidou network device is configured to generate a first physical frame based on the first user frame and the second user frame at a physical PHY layer;

[0047] The Beidou network device is used to send the first physical frame;

[0048] The first terminal is used to receive a first physical frame sent by a Beidou network device; parse the first user frame from the first physical frame, and discard the second user frame.

[0049] This allows BeiDou network equipment to simultaneously transmit user frames for multiple end users, enabling reliable and efficient transmission of outbound services within the constraints of low outbound data capacity. Furthermore, BeiDou network equipment can also transmit different types of user frames, thus meeting the needs of different outbound services.

[0050] In combination with the third aspect, in a possible implementation, the Beidou communication system may further include a second terminal, wherein the second terminal is used to receive a first physical frame sent by the Beidou network device; and parse the second user frame from the first physical frame.

[0051] In a possible implementation, the Beidou network device may also execute the method in any possible implementation of the first aspect above.

[0052] In a possible implementation manner, the terminal may also execute the method in any possible implementation manner of the second aspect above.

[0053] In a fourth aspect, the present application provides a communication device comprising one or more processors, one or more memories, and a transceiver. The transceiver and the one or more memories are coupled to the one or more processors, the one or more memories being configured to store computer program code, the computer program code comprising computer instructions. When the one or more processors execute the computer instructions, the communication device performs the method of any possible implementation of the first aspect described above.

[0054] The communication device may be a Beidou network device, or any network element or a combination of multiple network elements in the Beidou network device.

[0055] In a fifth aspect, the present application provides a communication device comprising one or more processors, one or more memories, and a transceiver. The transceiver and the one or more memories are coupled to the one or more processors, the one or more memories being configured to store computer program code, the computer program code comprising computer instructions. When the one or more processors execute the computer instructions, the communication device performs the method of any possible implementation of the second aspect described above.

[0056] The communication device may be a terminal or other product-type equipment.

[0057] In a sixth aspect, the present application provides a computer storage medium comprising computer instructions, which, when executed on a computer, enable the computer to execute the method in any possible implementation of the first aspect.

[0058] In a seventh aspect, the present application provides a computer storage medium comprising computer instructions, which, when executed on a computer, enable the computer to execute the method in any possible implementation of the second aspect.

[0059] In an eighth aspect, the present application provides a computer program product, which, when executed on a computer, enables the computer to execute the method in any possible implementation of the first aspect.

[0060] In a ninth aspect, the present application provides a computer program product, which, when executed on a computer, enables the computer to execute the method in any possible implementation of the second aspect.

[0061] In the tenth aspect, the present application provides a chip or chip system, which is applied to a terminal, including a processing circuit and an interface circuit, the interface circuit is used to receive code instructions and transmit them to the processing circuit, and the processing circuit is used to run the code instructions to execute the method in any possible implementation of the above-mentioned second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 1 is a schematic diagram of the architecture of a Beidou communication system 10 provided in an embodiment of the present application;

[0063] Figure 2 This is a schematic diagram of the data outbound transmission process in a Beidou communication system provided by an embodiment of the present application;

[0064] Figure 3 1 is a schematic diagram of a protocol encapsulation architecture for outbound data of a Beidou communication system 10 provided in an embodiment of the present application;

[0065] Figure 4 1 is a schematic diagram of a protocol parsing architecture for outbound data of a Beidou communication system 10 provided in an embodiment of the present application;

[0066] Figure 5 This is a schematic diagram of the data format of outbound data provided by an embodiment of the present application;

[0067] Figure 6 This is a schematic diagram of another data format of outbound data provided by an embodiment of the present application;

[0068] Figure 7A 1 is a schematic diagram of a frame format of an SLC frame provided in an embodiment of the present application;

[0069] Figure 7B 2 is a schematic diagram of another SLC frame format provided in an embodiment of the present application;

[0070] Figure 7C This is a schematic diagram of another SLC frame format provided in an embodiment of the present application;

[0071] Figure 7D This is a schematic diagram of another SLC frame format provided in an embodiment of the present application;

[0072] Figure 8A This is a schematic diagram of a successful transmission scenario of a transmission mechanism 1 of the SLC layer when data is outbound provided by an embodiment of the present application;

[0073] Figure 8B This is a schematic diagram of a transmission failure scenario of a first transmission mechanism of the SLC layer when data is outbound provided by an embodiment of the present application;

[0074] Figure 9A A schematic diagram of a successful transmission scenario of a second transmission mechanism of the SLC layer when data is outbound provided in an embodiment of the present application;

[0075] Figure 9B A schematic diagram of a transmission failure scenario of a second transmission mechanism of the SLC layer when data is outbound provided in an embodiment of the present application;

[0076] Figure 10AA schematic diagram of a successful transmission scenario of a third transmission mechanism of the SLC layer when data is outbound provided in an embodiment of the present application;

[0077] Figure 10B Schematic diagram of another successful transmission scenario of the SLC layer transmission mechanism 3 when data is outbound provided by an embodiment of the present application;

[0078] Figure 10C A schematic diagram of a transmission failure scenario of a third transmission mechanism of the SLC layer when data is outbound provided in an embodiment of the present application;

[0079] Figure 11A A schematic diagram of a transmission failure scenario of a fourth transmission mechanism of the SLC layer when data is outbound provided in an embodiment of the present application;

[0080] Figure 11B This is a flow chart of a method for controlling outbound transmission in a satellite communication system provided by an embodiment of the present application;

[0081] Figure 12 1 is a schematic structural diagram of the terminal 100 provided in an embodiment of the present application;

[0082] Figure 13 A schematic diagram of the structure of a communication device provided in an embodiment of the present application;

[0083] Figure 14 A schematic structural diagram of another communication device provided in an embodiment of the present application;

[0084] Figure 15 A schematic structural diagram of another communication device provided in an embodiment of the present application;

[0085] Figure 16 A schematic diagram of the structure of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0086] The terms used in the following examples of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. As used in the specification and appended claims of the present application, the singular expressions "a," "an," "said," "above," "the," and "this" are intended to include plural expressions as well, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used in the present application refers to and encompasses any or all possible combinations of one or more of the listed items.

[0087] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood to imply or suggest relative importance or implicitly indicate the number of the technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of this application, unless otherwise specified, "plurality" means two or more.

[0088] The following introduces a Beidou communication system 10 provided in an embodiment of the present application.

[0089] Figure 1 A schematic diagram of the architecture of a Beidou communication system 10 provided in an embodiment of the present application is shown.

[0090] As above Figure 1 As shown, the Beidou communication system 10 may include a terminal 100, a Beidou short message satellite 21, a Beidou network device 200, a short message center 25, and a terminal 300. Optionally, the Beidou communication system 10 may further include a national emergency rescue platform 26 and a national emergency rescue center 27.

[0091] Terminal 100 can send short messages to BeiDou short message satellites 21. BeiDou short message satellites 21 only relay the short messages sent by terminal 100 and directly forward them to BeiDou network devices 200 on the ground. BeiDou network devices 200 can parse the short messages forwarded by the satellites according to the BeiDou communication protocol and forward the general message content parsed from the short messages to a short message service center (SMSC) 25. The SMSC 25 can forward the message content to terminal 300 via a traditional cellular communication network. BeiDou network devices 200 can also transmit emergency messages sent by terminal 100 to the National Emergency Rescue Center 27 via the National Emergency Rescue Platform 26.

[0092] The terminal 300 can also send a short message to the short message center 25 through a traditional cellular communication network. The short message center 25 can forward the short message of the terminal 300 to the Beidou network device 200. The Beidou network device 200 can relay the short message of the terminal 300 to the terminal 100 via the Beidou short message satellite 21.

[0093] Among them, the above-mentioned Beidou network equipment 200 may include a Beidou ground transceiver station 22, a Beidou central station 23 and a Beidou short message fusion communication platform 24. Among them, the Beidou ground transceiver station 22 may include one or more devices with a sending function and one or more devices with a receiving function, or may include one or more devices with a sending function and a receiving function, which is not limited here. The Beidou ground transceiver station 22 can be used for the Beidou network equipment 200 to process data at the physical layer (physical layer protocol, PHY). The Beidou central station 23 can be used for the Beidou network equipment 200 to process data at the satellite link control layer (satellite link control protocol, SLC) layer and the message convergence layer (message data convergence protocol, MDCP). The Beidou short message fusion communication platform 24 can be used for the data processing function at the application layer (application layer protocol, APP).

[0094] Because the BeiDou communication system 10 communicates via satellite links, its main characteristics are long latency (approximately 270ms one-way) and high link loss. Currently, the BeiDou communication system 10 primarily supports short message bursts and does not support link state management, mobility management, or broadcast control information.

[0095] The working mode of the Beidou network device 200 may be a duplex mode, which allows data to be sent and received simultaneously.

[0096] The BeiDou network device 200 can send data to the terminal 100 via the BeiDou short message satellite 21. However, due to the current transmission capability of the BeiDou network device 200, the outbound service packet of the BeiDou network device 200 needs to be divided into multiple physical layer frames for transmission. In addition, since the civilian terminal (e.g., Figure 1 There are many types of services (e.g., short messages, large amounts of text information, picture information, voice information, etc.) sent by the terminal 300 in the Beidou network device to the terminal 100. Different service types have different requirements for the packet transmission mode of the underlying Beidou network device.

[0097] Therefore, an embodiment of the present application provides an outbound transmission control method in a satellite communication system, wherein the Beidou network device 200 can split the application layer message into multiple protocol data units (PDUs) at the MDCP layer, which can be referred to as MDCP PDUs. The MDCP PDU can include a successor indication field, wherein the successor indication field can be used to determine whether the current MDCP PDU is the starting MDCP PDU, the intermediate MDCP PDU, or the last MDCP PDU of multiple MDCP PDUs sent continuously; or an MDCP PDU sent separately. The Beidou network device 200 can sequentially send the MDCP PDU to the SLC layer as the service data unit (SDU) of the SLC layer, which can be referred to as an SLC SDU, and split the SLC SDU into N SLC PDUs at the SLC layer. Among them, SLC PDUs in multiple formats are provided to meet different business needs. The PHY layer can obtain the SLC PDUs of one or more users from the SLC layer. The PHY will splice the SLC PDUs of multiple users or one user together to form outbound data of a fixed-length physical time slot. Finally, the Beidou network device 200 can send the outbound data to one or more terminals.

[0098] In this way, the Beidou network device 200 can realize multi-frame transmission (a physical time slot can contain multiple user frames), can meet the outbound data needs of different business types, and can optimize the outbound resource configuration and improve the outbound resource utilization.

[0099] Figure 2 The embodiment of the present application provides a data outbound transmission process in a Beidou communication system.

[0100] like Figure 2 As described above, data outbound may refer to the Beidou network device 200 sending data to the terminal 100. For example, the Beidou short message fusion communication platform 24 in the Beidou network device 200 may send outbound data to the Beidou central station 23; the Beidou central station 23 may then send the outbound data to the Beidou ground transceiver station 22, which is relayed by the Beidou short message satellite 21 and then sent to the terminal 100. Upon receiving the data, the terminal 100 may return an SLC layer acknowledgment character (ACK) to the Beidou central station 23. The ACK may be used to confirm whether the terminal 100 has successfully received the outbound data sent by the Beidou network device 200.

[0101] The following describes a protocol encapsulation architecture for outbound data of a Beidou communication system 10 provided in an embodiment of the present application.

[0102] Figure 3A schematic diagram of a protocol encapsulation architecture for outbound data of a Beidou communication system 10 provided in an embodiment of the present application is shown.

[0103] like Figure 3 As shown, the BeiDou short message transmission protocol layer in the BeiDou network device 200 can be an application layer protocol, a message data convergence protocol (MDCP), a satellite link control protocol (SLC), and a physical layer protocol (PHY). Among them, the BeiDou network device 200 can include a BeiDou ground transceiver station 22, a BeiDou central station 23, and a BeiDou short message fusion communication platform 24. The BeiDou ground transceiver station 22 can be used to be responsible for the protocol processing of the PHY layer. The BeiDou central station 23 can be used to be responsible for the protocol processing of the SLC layer and the MDCP layer. The BeiDou short message fusion communication platform 24 can be used to be responsible for the protocol processing of the APP layer.

[0104] When the Beidou network device 200 sends data to the terminal 100, the workflow of the Beidou short message transmission protocol in the Beidou network device 200 may be as follows:

[0105] At the APP layer, the Beidou network device 200 may compress the original data into compressed data using a compression algorithm and add a compression indicator field to the front of the compressed data. The compression indicator field may be used to indicate the compression algorithm type used for the compressed data. The Beidou network device 200 may then encrypt the compressed data to obtain encrypted data and add an encryption algorithm field to the header of the encrypted data. The encryption algorithm field indicates the encryption algorithm type used for the encrypted data. The Beidou network device 200 may encapsulate the encrypted data, the compression indicator field, and the encryption indicator field into an application layer message and send it to the MDCP layer. The application layer message may include a message header and message data. The message header may include a compression indicator field and an encryption indicator field, among other fields. The message data includes the encrypted data.

[0106] Optionally, the Beidou network device 200 may also encrypt the compression indication field and the compressed data together to obtain encrypted data.

[0107] At the MDCP layer, the Beidou network device 200 can obtain the application layer message sent by the APP layer through the inter-layer interface and use the application layer message as an MDCP SDU. At the MDCP layer, the Beidou network device 200 can split an MDCP SDU into one or more fixed-length MDCP segment data (M_segement) and add a successor indication field to the header of each MDCP segment data to obtain an MDCP PDU. That is, the MDCP PDU includes an M_segement and a successor indication field. The successor indication field can be used to indicate whether the current MDCP PDU is the starting MDCP PDU, an intermediate MDCP PDU, or the last MDCP PDU of multiple MDCP PDUs sent continuously; or a single MDCP PDU sent separately.

[0108] At the SLC layer, the BeiDou network device 200 can obtain the MDCP PDU sent by the MDCP layer through the inter-layer interface as an SLC SDU. At the SLC layer, the BeiDou network device 200 can segment the SLC SDU into one or more (up to 4) fixed-length SLC segments (S_segement) and add frame header information to the header of each S_segement to obtain an SLC PDU.

[0109] It is understandable that the SLC layer needs to segment the data to accommodate the physical layer frame length. However, the SLC layer design allows one SLC SDU to be divided into a maximum of four SLC PDUs, so the MDCP layer also needs to segment the data.

[0110] At the PHY layer, the Beidou network device 200 can obtain the SLC PDU sent by the SLC layer through the inter-layer interface. The Beidou network device 200 can obtain the SLC PDU of one or more users from the SLC layer. The Beidou network device 200 can splice the SLC PDUs of multiple users together, add the frame header of the physical frame (such as the version number) as the code block of the PHY layer, and add a check bit (such as a cyclic redundancy check (CRC) code) at the end of the code block, and encode the code block and CRC code (such as polar coding). The encoded physical frame plus the reserved segment can form the coded data of the message branch (S2C_d branch) of a fixed-length physical time slot. Among them, the Beidou network device 200 can put multiple SLC PDUs of a user into different physical frames respectively. Then, the Beidou network device 200 combines the coded data of the S2C_d branch and the pilot information of the pilot branch (S2C_p branch) to form pilot coded data, that is, outbound data. The Beidou network device 200 can send outbound data to the Beidou short message satellite 21, which is then relayed to the terminal 100 via the Beidou short message satellite 21.

[0111] It is understood that the pilot information of the S2C_p branch is related to the satellite beam. When the satellite beam number is known, the pilot information of the S2C_p branch is also known and does not need to be decoded. However, the coded data of the S2C_d branch needs to be decoded.

[0112] The following describes a protocol parsing architecture for outbound data of a Beidou communication system 10 provided in an embodiment of the present application.

[0113] Figure 4 A schematic diagram of a protocol parsing architecture for outbound data of a Beidou communication system 10 provided in an embodiment of the present application is shown.

[0114] like Figure 4 As shown, the Beidou short message transmission protocol layer of the terminal 100 can be divided into an application layer (application layer protocol), a message data convergence protocol (MDCP), a satellite link control protocol (SLC) and a physical layer (PHY).

[0115] When the terminal 100 receives data sent by the Beidou network device, the workflow of the Beidou short message transmission protocol layer of the terminal 100 can be as follows:

[0116] At the PHY layer, the terminal 100 can obtain the pilot coded data after modulation and spread spectrum sent by the Beidou network device 200. The terminal 100 can despread the received spread spectrum modulated data (spread+modulated data) to obtain modulated data (modulated data). Then, the terminal 100 can demodulate the modulated data to obtain pilot coded data (pilot+data). Then, the terminal 100 can remove the pilot information in the pilot coded data to obtain coded data (code data). Then, the terminal 100 can decode the coded data and verify the integrity of the code block (code block) through the check data in the check bit field. If complete, the terminal 100 can extract the code block (code block) and present it to the SLC layer through the inter-layer interface as the SLC PDU of the SLC layer.

[0117] Here, the pilot coded data is the outbound data sent by the Beidou network device 200, and the outbound data consists of the coded data of the S2C_d branch and the pilot information of the pilot branch (S2C_p branch).

[0118] At the SLC layer, the terminal 100 can concatenate SLC PDUs belonging to the same SLC SDU into one SLC SDU based on the frame header information of the SLC PDU. The terminal 100 can present the SLC SDU to the MDCP layer through the inter-layer interface as an MDCP PDU of the MDCP layer.

[0119] At the MDCP layer, the terminal 100 may concatenate all MDCP PDUs belonging to the same MDCP SDU into one MDCP SDU. The terminal 100 may present the MDCP SDU to the APP layer via an inter-layer interface as an application layer message received by the APP layer.

[0120] At the APP layer, the terminal 100 may decrypt and decompress the application layer message based on the message header of the application layer message to obtain the original data.

[0121] In the embodiments of the present application, the above-mentioned protocol processing process is only an example, and the present application does not limit the specific operations of the protocol processing.

[0122] Next, the data format of the outbound data in the embodiment of the present application is introduced in detail.

[0123] Figure 5 The data format of outbound data provided by an embodiment of the present application is shown.

[0124] like Figure 5As shown, the outbound data is pilot-coded data at the physical layer. This pilot-coded data may include pilot data for the S2C_p branch (pilot branch) and data for the S2C_d branch (message branch). The pilot data for the S2C_p branch is used to assist the terminal in parsing user frames in the message branch. The S2C_d branch may contain data (user frames) sent by the station to multiple terminals, as well as a reserved field, a rate indication field, and a CRC checksum field.

[0125] Terminal 100 can obtain data sent to it by the base station from the S2C_d branch. Simply put, terminal 100 searches for the S2C_p branch and then demodulates the S2C_d branch via the S2C_p branch. After receiving outbound data, terminal 100 can parse the user frame data in the S2C_d branch into SLC PDUs (also known as SLC frames or user frames) at the SLC layer.

[0126] like Figure 5 As shown in FIG, the SLC PDU may include a user frame header field and a user information field. The user frame header field may include a start identifier field, a frame length field, and a user ID field. The user information field may include a user frame type field and a user message field.

[0127] The Start Identifier field is used to identify the beginning of the user frame and can be 8 bits long. The Frame Length field is used to identify the length of the user frame and can be 8 or 9 bits long. The User ID field is used to indicate the terminal device receiving the user frame and can be 44 bits long. It should be understood that the embodiments of the present application do not limit the lengths of the Start Identifier field, Frame Length field, and User ID field.

[0128] If the user ID field in the SLC PDU parsed by the SLC layer of terminal 100 from the user frame data in the S2C_d branch is the same as the user ID of terminal 100, terminal 100 can combine one or more SLC PDUs into an SLC SDU packet at the SLC layer and then transmit it to the MDCP layer for parsing. If the user ID field in the SLC PDU parsed by terminal 100 from the user frame data in the S2C_d branch is different from the user ID of the terminal, terminal 100 can discard the SLC PDU.

[0129] The User Message field may contain specific content sent by the station to the terminal. This content may include the terminal's mailbox profile, a mail message, an ACK frame, a NACK frame, and so on, without limitation. The User Frame Type field may be used to indicate the type of user frame. The User Frame Type field may be 2 bits long. It should be understood that the embodiments of this application do not impose any restrictions on the length of the User Frame Type field. The service type indicated by the User Frame Type field may be as shown in Table 1 below.

[0130] Table 1

[0131] User Frame Type field type illustrate 00 Generic Data Frame Message information transmission (including mailbox overview) 01 ACK frame Acknowledgement frame for inbound data 10 Receipt frame Reliable Receive Receipt Frame 11 RSV

[0132] As shown in Table 1, when the User Frame Type field of a user frame is "00", it indicates that the user frame is a general data frame; when the User Frame Type field of a user frame is "01", it indicates that the user frame is an ACK frame; when the User Frame Type field of a user frame is "10", it indicates that the user frame is a receipt frame. The User Frame Type field "11" is a reserved field.

[0133] Because terminal 100 can perform blind decoding on received physical frames, there is no need to design a rate indication field, saving bits in this field. As outbound data protocols continue to evolve, a field is needed to indicate different protocol versions. Therefore, an alternative data format for outbound data is provided.

[0134] Figure 6 Another data format of outbound data provided by an embodiment of the present application is shown.

[0135] like Figure 6 As shown, the outbound data is pilot-coded data of the physical layer. The pilot-coded data may include pilot data of the S2C_p branch (pilot branch) and data of the S2C_d branch (data branch). The pilot data of the S2C_p branch is used to assist the terminal in parsing the user frames in the data branch. The S2C_d branch may contain data (user frames) sent by the station side to multiple terminals, as well as a reserved field, a version number field, and a CRC check code field. The version number field may be 3 bits, and the embodiment of the present application does not limit the length of the version number field.

[0136] Terminal 100 can obtain data sent to it by the base station from the S2C_d branch. Simply put, terminal 100 searches for the S2C_p branch and then demodulates the S2C_d branch via the S2C_p branch. After receiving outbound data, terminal 100 can parse the user frame data in the S2C_d branch into SLC PDUs (also known as SLC frames or user frames) at the SLC layer.

[0137] like Figure 6As shown, the SLC PDU may include a user frame header field and a user information field. In the embodiment of the present application, four types of SLC PDU frame formats are provided. When the SLC frame type is different, the frame format of the SLC frame is also different. For details, please refer to the description below and will not be repeated here.

[0138] Figure 7A The figure shows a frame format of an SLC frame provided by an embodiment of the present application.

[0139] like Figure 7A As shown, the SLC frame can be a general data frame with a 2K rate. This general data frame with a 2K rate can be used for mailbox profile query and letter message sending. For example, when the terminal 100 sends a mailbox profile query request to the Beidou network device 200, the SLC frame that the Beidou network device 200 replies to the terminal 100 can be a general data frame with a 2K rate.

[0140] like Figure 7A As shown, the 2K rate general data may include a single user frame header and user information. The single user frame header of the user frame may include a frame type field, an acknowledge mode enable (AM enable) field, a frame length field, a user ID field, a total number of frames field, and a frame sequence number field.

[0141] The frame type field may be used to indicate the type of the SLC frame. The length of the frame type field may be 2 bits. The embodiment of the present application does not limit the length of the frame type field.

[0142] The AM enable field indicates whether the terminal receiving the SLC frame needs to reply an ACK to the Beidou network device 200. The length of the AM enable field can be 1 bit. If the value in the AM enable field is a first value (for example, 1), it indicates that the terminal 100 needs to reply an ACK to the Beidou network device 200 after receiving the user frame. If the value in the AM enable field is a second value (for example, 0), it indicates that the terminal 100 does not need to reply an ACK to the Beidou network device 200 after receiving the SLC frame. The embodiment of the present application does not limit the length of the AM enable field or the specific value of the AM enable field.

[0143] It is understood that in the embodiment of the present application, if the value in the AM enable field is the first value, that is, the mode in which the terminal 100 needs to reply ACK to the Beidou network device 200 after receiving the user frame, it can be called acknowledge mode (AM mode for short). If the value in the AM enable field is the second value, that is, the mode in which the terminal does not need to reply ACK to the Beidou network device 200 after receiving the SLC frame, it can be called unacknowledge mode (UM mode for short).

[0144] The frame length field is used to identify the length of the SLC frame, and the length of the frame length field can be 8 bits. The embodiment of the present application does not limit the length of the frame length field.

[0145] The User ID field may indicate that the SLC frame is sent by the Beidou network device 200 to the first terminal, and the ID of the first terminal is the same as the ID shown in the User ID field. The length of the User ID field may be 44 bits. The embodiment of the present application does not limit the length of the User ID field.

[0146] The total number of frames field is used to indicate the number of SLC frames sent by the Beidou network device 200 to a single user's terminal. The length of the total number of frames field can be 2 bits. The embodiment of the present application does not limit the length of the total number of frames field.

[0147] The Frame Sequence Number field is used to indicate that the SLC frame is the Nth frame among all SLC frames sent by Beidou network device 200 to a single user's terminal. The value of N corresponds to the value described in the Frame Sequence Number field. The Frame Sequence Number field can be 2 bits long. This embodiment of the application does not limit the length of the User ID field.

[0148] It is understandable that Figure 7A The format of the single user frame header in the SLC frame is only an example. The embodiment of the present application does not limit the order of arrangement of the fields in the single user frame header and the number of fields included in the single user frame header.

[0149] Figure 7B The figure shows the frame format of another type of SLC frame provided by an embodiment of the present application.

[0150] like Figure 7B As shown, the SLC frame is a universal data frame at a 4K rate. The universal data frame at a 4K rate may include a single user frame header and user information. The single user frame header of the user frame may include a frame type field, an AMenable (AM mode enabled) field, a frame length field, a user ID field, a total number of frames field, and a frame sequence number field.

[0151] The frame type field may be used to indicate the type of the user frame. The length of the frame type field may be 2 bits.

[0152] The AM enable field indicates whether the terminal receiving the SLC frame needs to reply an ACK to the Beidou network device 200. The length of the AM enable field can be 1 bit. If the value in the AM enable field is D1 (for example, a binary value of 1), it indicates that the terminal needs to reply an ACK to the Beidou network device 200 after receiving the user frame. If the value in the AM enable field is D2 (for example, a binary value of 0), it indicates that the terminal does not need to reply an ACK to the Beidou network device 200 after receiving the SLC frame. The embodiments of the present application do not limit the length of the AM enable field or the specific value of the AM enable field.

[0153] The frame length field is used to identify the length of the SLC frame. The length of the frame length field is determined by the physical layer decoding parameters (i.e., the decoding rate). For example, the length of the frame length field can be 9 bits. The embodiment of the present application does not limit the length of the frame length field.

[0154] The User ID field may indicate that the SLC frame is sent by the Beidou network device 200 to the first terminal, and the ID of the first terminal is the same as the ID shown in the User ID field. The length of the User ID field may be 44 bits. The embodiment of the present application does not limit the length of the User ID field.

[0155] The total number of frames field is used to indicate the number of SLC frames sent to a single user terminal by the Beidou network device 200. The length of the total number of frames field can be 2 bits. The embodiment of the present application does not limit the length of the total number of frames field.

[0156] The Frame Sequence Number field is used to indicate that the SLC frame is the Nth frame among all user frames sent by Beidou network device 200 to terminal 100. The value of N is the value described in the specific content of the Frame Sequence Number field. The length of the Frame Sequence Number field can be 2 bits. The embodiment of the present application does not limit the length of the User ID field.

[0157] It is understandable that Figure 7B The format of a single user frame header in an SLC frame is shown for illustrative purposes only. The present embodiment does not limit the order of the fields in the single user frame header or the number of fields included in the single user frame header. For example, the first field in the single user frame header can be any one of the frame type field, the AM enable field, the frame length field, the user ID field, the total number of frames field, and the frame sequence number field.

[0158] Here, in one possible implementation, the terminal may perform blind decoding on the received SLC frame. That is, the terminal may parse the SLC frame at each rate that the terminal can parse. If the terminal can parse the SLC frame at a first rate, the rate of the SLC frame is the first rate. The terminal may then determine the length of the frame header information in the SLC frame based on the rate.

[0159] Figure 7C The figure shows the frame format of another type of SLC frame provided by an embodiment of the present application.

[0160] like Figure 7C As shown, the SLC frame is an ACK frame, which is used only at the SLC layer. The ACK frame may include a single user frame header and user information. The length of the single user frame header may be 36 bits, and the length of the user information may be 4 bits. This embodiment of the application does not limit the length of the single user frame or the length of the user information.

[0161] The single user frame header may include a frame type field and a user ID field. The frame type field may be used to indicate the type of the SLC frame. The length of the frame type field may be 2 bits. The embodiment of the present application does not limit the length of the frame type field.

[0162] The User ID field may indicate that the SLC frame is sent by the Beidou network device 200 to the first terminal, and the ID of the first terminal is the same as the ID shown in the User ID field. The length of the User ID field may be 44 bits. The embodiment of the present application does not limit the length of the User ID field.

[0163] The user information may include an ACK bitmap, which is used to indicate whether the Beidou network device 200 has successfully received the SLC frame sent by the terminal 100 to the Beidou network device 200.

[0164] Furthermore, in one possible implementation, the length of the ACK bitmap in the ACK frame sent by Beidou network device 200 to terminal 100 can be determined based on the maximum number of SLC PDUs into which the SLC SDU sent by terminal 100 to Beidou network device 200 can be segmented. Since the maximum number of SLC PDUs into which an SLC SDU can be segmented is fixed, the length of the ACK bitmap is also fixed. For example, if the SLC SDU sent by terminal 100 to Beidou network device 200 can be segmented into a maximum of four SLC PDUs, the length of the ACK bitmap can be 4 bits.

[0165] Furthermore, in a possible implementation, the Nth bit in the ACK bitmap is the value D3 (eg, binary value 1), indicating that the Beidou network device 200 has successfully received the Nth frame sent by the terminal 100 to the Beidou network device 100 .

[0166] For example, if Beidou network device 200 successfully receives four SLC frames sent by terminal 100, the user information of the SLC frame that Beidou network device 200 replies to terminal 100 may be an ACK bitmap of "1111". If terminal 100 sends four SLC frames to Beidou network device 200, and Beidou network device 200 only successfully receives the first SLC frame of the user's current SLC SDU, and fails to successfully receive the subsequent three inbound SLC frames, the user information of the SLC frame that Beidou network device 200 replies to terminal 100 may be an ACK bitmap of "1000".

[0167] It is understandable that the user information in the ACK frame can be designed as an ACK bitmap with a fixed length and very short content, so the ACK does not need to distinguish the rate.

[0168] Figure 7D The frame format of another type of SLC frame provided by an embodiment of the present application is shown.

[0169] like Figure 7D As shown, the SLC frame can be an application layer receipt frame, which is translated into information 1 (for example, all 1 indication) at the SLC layer and continues to be parsed at the application layer. The application layer receipt frame may include a single user frame header and user information. After the terminal 100 receives the application layer receipt frame sent by the Beidou network device 200, the terminal 100 can parse the single user frame header of the application layer receipt frame at the SLC layer. The user information in the application layer receipt frame can be parsed by the application layer. The length of the single user frame header can be 36 bits, and the length of the user information can be 4 bits. The embodiment of the present application does not limit the length of the single user frame and the length of the user information.

[0170] A single user frame header may include a frame type field and a user ID field. The frame type field may be used to indicate the type of the user frame. The frame type field may be 2 bits long. The embodiment of the present application does not limit the length of the frame type field.

[0171] The User ID field may indicate that the SLC frame is sent by the Beidou network device 200 to the first terminal, and the ID of the first terminal is the same as the ID shown in the User ID field. The length of the User ID field may be 44 bits. The embodiment of the present application does not limit the length of the User ID field.

[0172] The user information may be an error code field, which may be parsed by the application layer. The length of the error code field may be 4 bits. The embodiment of the present application does not limit the length of the error code field.

[0173] The following describes the transmission mechanism of the SLC layer when data is outbound in the Beidou communication system 10 provided in an embodiment of the present application.

[0174] 1. Transmission Mechanism 1

[0175] The BeiDou network device 200 does not have the function of reclaiming and reallocating outbound resources. That is, the BeiDou network device 200 reclaims the resources allocated to each SLC PDU in an SLC SDU and reallocates them to the SLC SDUs sent by the BeiDou network device 200 to other users.

[0176] The Beidou network device 200 sends an SLC PDU in an SLC SDU to the terminal 100. When the terminal 100 receives the first SLC PDU, it begins calculating the maximum waiting time for the terminal 100 to receive the SLC PDU in the SLC SDU, i.e., the length of the time window for the terminal 100 to receive the SLC PDU. After the Beidou network device 200 has transmitted the last SLC PDU in an SLC SDU, it can calculate the maximum waiting time for the Beidou network device 200 to receive the terminal's reply ACK, i.e., the length of the time window for the Beidou network device 200 to receive the ACK. When the terminal 100 successfully receives the SLC SDU sent by the Beidou network device 200, it can send an ACK to the Beidou network device 200. If the terminal 100 fails to successfully receive the SLC SDU sent by the Beidou network device 200, it does not send a NACK to the Beidou network device 200.

[0177] In the embodiment of the present application, the terminal 100 successfully receiving the SLC SDU sent by the Beidou network device 200 may mean that the terminal 100 receives all SLC PDUs in the SLC SDU sent by the Beidou network device 200 and can correctly parse all SLC PDUs in the SLC SDU.

[0178] In the embodiment of the present application, the terminal 100 fails to successfully receive the SLC SDU sent by the Beidou network device 200, which may mean that the terminal 100 fails to receive all SLC PDUs in the SLC SDU sent by the Beidou network device 200, or fails to correctly parse all SLC PDUs in the SLC SDU.

[0179] It can be understood that when the terminal 100 successfully receives the SLC SDU sent by the Beidou network device 200, the character replied by the terminal 100 can be simply referred to as ACK. When the terminal 100 fails to successfully receive the SLC SDU sent by the Beidou network device 200, that is, the reception fails, the character replied by the terminal can be simply referred to as NACK.

[0180] It is understandable that if the SLC PDU of the SLC SDU sent by the Beidou network device 200 to the terminal 100 is in UM mode, then after the terminal 100 receives the SLC SDU from the Beidou network device 200, regardless of whether the reception is successful or failed, it is not necessary to reply ACK or NACK to the Beidou network device 200.

[0181] 1.1 Transfer successful

[0182] Figure 8A A schematic diagram of a successful transmission scenario of an SLC layer transmission mechanism when data is outbound provided in an embodiment of the present application is shown.

[0183] like Figure 8A As shown, the communication interaction process of the Beidou communication system 10 at the SLC layer can be as follows:

[0184] (1) The BeiDou network device 200 may send N SLC PDUs in the SLC SDU at equal intervals in ascending order of frame sequence numbers, where N≤M, and M is the maximum number of segments of the SLC SDU. In the embodiment of the present application, M is equal to 4 for illustrative purposes.

[0185] (2) After receiving the first SLC PDU sent by the Beidou network device 200, the terminal 100 starts the SLC layer receiving session at time t0, calculates the maximum waiting time (tUeRevWindow) of the terminal 100 receiving the outbound SLC SDU receiving window, and feeds back ACK to the Beidou network device 200 after the SLC SDU receiving window ends.

[0186] Optionally, the data portion of the ACK may occupy 1 bit. Since the BeiDou network device 200 does not have a retransmission function, the terminal 100 does not need to notify the BeiDou network device 200 which SLC PDU is not received. The terminal 100 only needs to notify the BeiDou network 200 of a successful or failed reception.

[0187] Optionally, the data portion of the ACK may be character C1 or character C2. Character C1 may be used to indicate that the terminal 100 successfully receives an SLC SDU sent by the Beidou network device 200. Character C2 may be used to indicate that the terminal 100 fails to successfully receive an SLC SDU sent by the Beidou network device 200. For example, character C1 may be character 1, and character C2 may be character 0.

[0188] (3) After sending the Nth SLC PDU, the Beidou network device 200 receives the ACK fed back by the terminal 100 within the ACK receiving window.

[0189] Next, we will introduce the above Figure 8A The parameters shown in and their meanings.

[0190] (1) tUeProcess: refers to the processing delay from the terminal 100 receiving the SLC PDU sent by the Beidou network device 200 to sending the ACK. According to experimental data, the typical value of tUeProcess can be 60ms.

[0191] (2) tPropagate: refers to the air interface propagation delay between the terminal 100 and the BeiDou network device 200. According to experimental data, the typical value of tPropagate is 270ms.

[0192] (3) tStationStartRcvAck: refers to the starting time when the Beidou network device 200 receives ACK.

[0193] (4) tStationEndRcvAck: refers to the end time when the Beidou network device 200 receives ACK.

[0194] (5) tStationRevAckWindow: refers to the duration window length of the Beidou network device 200 receiving ACK.

[0195] (6) tUeRevWindow: refers to the time window length for the terminal 100 to receive the SLC PDU, also known as the SLC PDU receiving window.

[0196] (7) nUeRevFrameSN: refers to the frame sequence number of the SLC PDU currently received by the terminal 100. In this embodiment of the present application, since the SLC SDU can include a maximum of 4 SLC PDU frames, 0≤nStationRevFrameSN≤3, and nStationRevFrameSN is an integer.

[0197] (8) tStationFrameLen: refers to the length of the SLC PDU sent by the Beidou network device 200. In the embodiment of the present application, the value of tStationFrameLen can be 125ms.

[0198] (9) nStationTotalFrameNum: refers to the total number of frames into which the Beidou network device 200 segments the SLC SDU, that is, the total number of frames including the SLC PDU in one SLC SDU.

[0199] (10) tStationTxInterval: refers to the time interval for the Beidou network device 200 to send SLC PDUs. The SLC PDU transmission interval (tStationTxInterval) can refer to the interval between the start transmission times of two adjacent SLC PDUs. tStationTxInterval is a preset value, where, for example, a typical value of tStationTxInterval can be 2s.

[0200] (11) tUeSendAck: refers to the time when the terminal 100 sends ACK to the Beidou network device 200.

[0201] (12) tStationTxEnd: refers to the time when the Beidou network device 200 sends the last SLC PDU.

[0202] (13) tUeUlFrameLen: refers to the duration of the ACK sent by the terminal 100. 128ms≤tUeUlFrameLen≤512ms.

[0203] (14) δ: refers to the time alignment deviation of the outbound physical frame transmission on the Beidou network device 200. The Beidou network device 200 may not complete signal processing and scheduling at the time of the outbound physical frame transmission. It needs to wait for the next outbound physical frame transmission time before transmitting the physical frame. Where 0 < δ ≤ 125ms.

[0204] Next, it is specifically introduced how the terminal 100 determines the SLC PDU receiving window length and how the Beidou network device 200 determines the start time of the ACK receiving window and the end time of the ACK window in the embodiment of the present application.

[0205] (1) The terminal 100 starts the session by receiving the first frame of the SLC SDU. The terminal 100 can determine the duration of the SLC PDU receiving window on the terminal 100 based on the frame sequence number of the currently received SLC PDU, the duration of the SLC PDU transmission by the Beidou network device 200, the total number of SLC PDU frames in the current SLC SDU session, and the SLC PDU transmission interval.

[0206] The terminal 100 can determine the time length of the SLC PDU receiving window by the following formula (1):

[0207]

[0208] In the above formula (1), tUeRevWindow is the time window length for the terminal 100 to receive the SLC PDU.

[0209] nStationTotalFrameNum is the total number of SLC PDU frames in the current SLC SDU session. nStationRevFrameSN is the frame sequence number of the SLC PDU currently received by the terminal 100. tStationTxInterval is the SLC PDU transmission interval on the Beidou network device 200. The above nRevFrameSN = {0, 1, ..., nStationTotalFrameNum-1}. Generally, nStationTotalFrameNum can be 4, then nRevFrameSN = {0, 1, 2, 3}. tStationFrameLen is the length of the SLC PDU sent by the Beidou network device 200. The length of tStationFrameLen is variable. In the embodiment of the present application, the value of tStationFrameLen can be 125ms. δ is the transmission time alignment deviation of the outbound physical frame on the Beidou network device 200. The value of δ can be 125ms.

[0210] (2) After the receiving window for receiving the SLC PDU ends, the terminal 100 performs information processing and constructs the Ack_Bit information. Finally, the terminal 100 carries the Ack_Bit information in an ACK frame and sends it to the Beidou network device 200. The terminal 100 can determine the time point for sending the ACK based on the length of the SLC PDU receiving window and the processing delay from the terminal 100 receiving the SLC PDU sent by the Beidou network device 200 to sending the ACK.

[0211] The terminal 100 can determine the time point for returning the ACK by using the following formula (2):

[0212] tUeSendAck = tUeRevWindow + tUeProcess Formula (2)

[0213] Wherein, in the above Formula (2), tUeSendAck is the time when the terminal 100 sends an ACK to the Beidou network device 200. tUeRevWindow is the length of the time window for the terminal 100 to receive the SLC PDU. tUeProcess represents the processing delay of the terminal 100 from receiving the SLC PDU sent by the Beidou network device 200 to sending an ACK.

[0214] (3) The Beidou network device 200 can determine the starting time for the Beidou network device 200 to receive an ACK based on the moment when the Beidou network device 200 sends the last SLC PDU in the SLC SDU, the processing delay of the terminal 100 from receiving the SLC PDU sent by the Beidou network device 200 to sending an ACK, and the radio propagation delay between the terminal 100 and the Beidou network device 200.

[0215] Wherein, the Beidou network device 200 can determine the starting time for receiving an ACK through the following Formula (3):

[0216] tStationTxEnd < tStationStartRcvAck < tStationTxEnd + 2 * tPropagate + tUeProcess Formula (3)

[0217] Wherein, in the above Formula (3), tStationStartRcvAck is the starting time for the Beidou network device 200 to receive an ACK, tStationTxEnd is the moment when the Beidou network device 200 sends the last SLC PDU. tUeProcess is the processing delay of the terminal 100 from receiving the SLC PDU sent by the Beidou network device 200 to sending an ACK. tPropagate is the radio propagation delay between the terminal 100 and the Beidou network device 200.

[0218] In the above Formula (3), tUeProcess takes the minimum value of the processing delay of the terminal 100 from receiving the SLC PDU sent by the Beidou network device 200 to sending an ACK.

[0219] The Beidou network device 200 can determine the moment when the Beidou network device 200 sends the last SLC PDU based on the total number of frames into which the Beidou network device 200 segments the SLC SDU and the time interval for the Beidou network device 200 to send the SLC PDU.

[0220] The BeiDou network device can determine the time when the BeiDou network device 200 sends the last SLC PDU by using the following formula (4):

[0221] tStationTxEnd=(nStationTotalFrameNum-1)*(tStationTxInterval+tStationFrameLen)+δ formula (4)

[0222] In the above formula (4), tStationTxEnd is the time when the Beidou network device 200 sends the last SLC PDU. nStationTotalFrameNum is the total number of frames that the Beidou network device 200 segments the SLC SDU. tStationTxInterval is the time interval at which the Beidou network device 200 sends the SLC PDU. tStationFrameLen is the length of the SLC PDU sent by the Beidou network device 200. The length of tStationFrameLen is variable. In the embodiment of the present application, the value of tStationFrameLen can be 125ms. δ is the transmission time alignment deviation of the outbound physical frame on the Beidou network device 200. The value of δ can be 125ms.

[0223] (4) The Beidou network device 200 can determine the end time of receiving the ACK by the Beidou network device 200 based on the time when the Beidou network device 200 sends the last SLC PDU, the air interface propagation delay between the terminal 100 and the Beidou network device 200, the processing delay from the terminal 100 receiving the SLC PDU sent by the Beidou network device 200 to sending the ACK, and the time length of the ACK sent by the terminal 100.

[0224] The Beidou network device 200 can determine the end time of receiving the ACK by the Beidou network device 200 using the following formula (5):

[0225] tStationEndRcvAck=tStationTxEnd+2*tPropagate+tUeProcess+tUeUlFrameLen formula (5)

[0226] In formula (5), tStationEndRcvAck is the time when Beidou network device 200 ends receiving the ACK. tStationTxEnd is the time when Beidou network device 200 sends the last SLC PDU. tUeProcess is the processing delay from the time terminal 100 receives the SLC PDU sent by Beidou network device 200 to the time it sends the ACK. tPropagate is the air interface propagation delay between terminal 100 and Beidou network device 200. tUeUlFrameLen is the duration of the ACK sent by terminal 100.

[0227] In the above formula (5), tUeProcess takes the maximum value of the processing delay from the terminal 100 receiving the SLCPDU sent by the Beidou network device 200 to sending the ACK.

[0228] 1.2 Transmission Failure

[0229] In one possible implementation, terminal 100 does not receive all SLC PDUs in an SLC SDU sent by Beidou network device 200. Terminal 100 does not send back ACK information to Beidou network device 200. If Beidou network device 200 does not receive an ACK from terminal 100 after the ACK receive window times out (if it has not received an ACK after tStationEndRcvAck is reached), Beidou network device 200 ends transmission of this SLC SDU.

[0230] Figure 8B A schematic diagram of a transmission failure scenario in an SLC layer transmission mechanism when data is outbound provided in an embodiment of the present application is shown.

[0231] like Figure 8B As shown, the terminal 100 does not receive the last SLC SDU in the SLC SDU sent by the Beidou network device 200. The terminal 100 does not reply ACK to the Beidou network device 200. The Beidou network device 200 does not receive the ACK feedback from the terminal 100 within the ACK receiving window, and the Beidou network device 200 ends the transmission of this SLC SDU.

[0232] 2. Transmission Mechanism 2

[0233] Beidou network devices do not have the function of reclaiming or reallocating outbound resources. When Beidou network device 200 sends an SLC SDU to terminal 100, terminal 100 calculates the receiving window for the SLC SDU based on the maximum transmission time interval. If terminal 100 successfully receives the SLC SDU within the receiving window, it is not necessary to send an ACK to Beidou network device 200. If terminal 100 fails to successfully receive the SLC SDU within the receiving window, it is not necessary to send a NACK to Beidou network device 200.

[0234] 2.1 Transfer Successful

[0235] Figure 9A A schematic diagram of a successful transmission scenario in a second transmission mechanism of the SLC layer when data is outbound provided in an embodiment of the present application is shown.

[0236] like Figure 9A As shown, the Beidou network device 200 can send the four SLC PDUs in the SLC SDU at equal intervals in ascending order of frame sequence numbers. After receiving the first SLC PDU sent by the Beidou network device 200, the terminal 100 starts the SLC layer receive session at time t0 and calculates the maximum waiting time (tUeRevWindow) of the terminal 100's receive window for receiving outbound SLC SDUs. After the terminal 100 successfully receives all SLC PDUs in the SLC SDU within the time window tUeRevWindow, it does not reply ACK to the Beidou network device 200.

[0237] 2.2 Transmission Failure

[0238] Figure 9B A schematic diagram of a transmission failure scenario in a second transmission mechanism of the SLC layer when data is outbound provided in an embodiment of the present application is shown.

[0239] like Figure 9B As shown, the Beidou network device 200 sends the four SLC PDUs in the SLC SDU at equal intervals in ascending order of frame sequence number. After receiving the first SLC PDU sent by the Beidou network device 200, the terminal 100 starts the SLC layer receive session at time t0 and calculates the maximum waiting time (tUeRevWindow) of the terminal 100's receive window for receiving outbound SLC SDUs. The terminal 100 does not receive the last SLC PDU in an SLC SDU sent by the Beidou network device 200. The terminal 100 does not need to reply a NACK to the Beidou network device 200.

[0240] 3. Transmission Mechanism 3

[0241] Beidou network devices have the ability to reclaim and reallocate outbound resources. When Beidou network device 200 sends an SLC SDU to terminal 100, terminal 100 calculates the receiving window for the SLC SDU based on the maximum transmission time interval. If terminal 100 successfully receives an SLC SDU within the receiving window, it can respond with an ACK to Beidou network device 200. If the first frame received by terminal 100 is not the first SLC PDU in the SLC SDU sent by Beidou network device 200, terminal 100 immediately responds with a NACK to Beidou network device 200 and ends the reception process.

[0242] 3.1 Transmission Success

[0243] Figure 10A It shows a schematic diagram of the transmission success scenario in Transmission Mechanism 3 of the SLC layer when data is outbound in an embodiment of the present application.

[0244] As Figure 10A shown, when the Beidou network device 100 starts to send the first SLC PDU in the SLC SDU, it starts to calculate the reception window of the ACK fed back by the receiving terminal 100. The Beidou network device 200 can send 4 SLC PDUs in the SLC SDU at equal intervals in the order of the frame sequence numbers from small to large. After receiving the first SLC PDU sent by the Beidou network device 200, the terminal 100 starts an SLC layer reception session at time t0 and calculates the maximum waiting time (tUeRevWindow) of the reception window of the SLC SDU received by the terminal 100 for outbound. After successfully receiving all the SLC PDUs in the SLC SDU within the time window tUeRevWindow, the terminal 100 replies ACK to the Beidou network device 200.

[0245] As Figure 10A shown, optionally, in a possible implementation manner, the Beidou network device 200 can determine the starting moment for the Beidou network device 200 to receive ACK according to the moment when the Beidou network device 200 starts to send the first SLC PDU in an SLC SDU, the moment when the Beidou network device 200 finishes sending the last SLC PDU in the SLC SDU, the processing delay from when the terminal 100 receives the SLC PDU sent by the Beidou network device 200 to when it sends ACK, and the radio propagation delay between the terminal 100 and the Beidou network device 200.

[0246] Among them, the Beidou network device 200 can determine the starting moment for receiving ACK through the following formula (6):

[0247] tStationTxStart < tStationStartRcvAck < tStationTxEnd + 2 * tPropagate + tUeProcess Formula (6)

[0248] In formula (6), tStationStartRcvAck is the time when Beidou network device 200 starts receiving the ACK, tStationTxStart is the time when Beidou network device 200 starts sending the first SLC PDU in an SLC SDU, tStationTxEnd is the time when Beidou network device 200 sends the last SLC PDU, tUeProcess is the processing delay from the time terminal 100 receives the SLC PDU sent by Beidou network device 200 to the time it sends the ACK, and tPropagate is the air interface propagation delay between terminal 100 and Beidou network device 200.

[0249] It is understandable that when the terminal 100 successfully receives the last SLC PDU in the SLC SDU sent by the Beidou network device 200, the ACK replied by the terminal 100 to the Beidou network device 200 may be the first character, such as the character "1".

[0250] Figure 10B A schematic diagram of another successful transmission scenario in the third transmission mechanism of the SLC layer when data is outbound provided in an embodiment of the present application is shown.

[0251] like Figure 10B As shown, after sending the first SLC PDU in the SLC SDU, the Beidou network device 100 starts calculating the receiving window for receiving the ACK fed back by the terminal 100. The Beidou network device 200 can send the four SLC PDUs in the SLC SDU at equal intervals in order of frame sequence number from small to large. After receiving the first SLC PDU sent by the Beidou network device 200, the terminal 100 starts the SLC layer receiving session (session) at time t0 and calculates the maximum waiting time (tUeRevWindow) of the receiving window for the terminal 100 to receive the outbound SLC SDU. After successfully receiving all SLC PDUs in the SLC SDU within the time window tUeRevWindow, the terminal 100 replies ACK to the Beidou network device 200.

[0252] like Figure 10B As shown, optionally, in one possible implementation, the Beidou network device 200 can determine the starting time when the Beidou network device 200 receives the ACK based on the time when the Beidou network device 200 starts to send the first SLC PDU in an SLC SDU, the outbound frame length sent by the Beidou network device 200, the time when the Beidou network device 200 completes sending the last SLC PDU in the SLC SDU, the processing delay of the terminal 100 from receiving the SLC PDU sent by the Beidou network device 200 to sending the ACK, and the air interface propagation delay between the terminal 100 and the Beidou network device 200.

[0253] The Beidou network device 200 can determine the starting time of receiving ACK by the following formula (6):

[0254]

[0255] In the above formula (7), tStationStartRcvAck is the starting time when the Beidou network device 200 receives the ACK, tStationTxStart is the time when the Beidou network device 200 starts to send the first SLC PDU in an SLC SDU. tStationTxEnd is the time when the Beidou network device 200 sends the last SLC PDU. tUeProcess is the processing delay from the terminal 100 receiving the SLC PDU sent by the Beidou network device 200 to sending the ACK. tPropagate is the air interface propagation delay between the terminal 100 and the Beidou network device 200. tStationFrameLen is the length of the SLC PDU sent by the Beidou network device 200. Generally, tStationFrameLen is 125ms.

[0256] 3.2 Transmission Failure

[0257] Figure 10C A schematic diagram of a transmission failure scenario in a third transmission mechanism of the SLC layer when data is outbound provided in an embodiment of the present application is shown.

[0258] like Figure 10C As shown, after sending the first SLC PDU in the SLC SDU, the BeiDou network device 100 starts to calculate the receiving window for the ACK fed back by the receiving terminal 100. The BeiDou network device 200 can send the four SLC PDUs in the SLC SDU at equal intervals in the order of the frame sequence numbers from small to large. The BeiDou network device 200 has sent the first SLC PDU (i.e. Figure 10C The SLC PDU with sequence number 0) and the second SLC PDU (i.e. Figure 10C1 in the SLC PDU). After receiving the first SLC PDU sent by the Beidou network device 200, the terminal 100 starts the SLC layer receiving session (session) at time t0 and calculates the maximum waiting time (tUeRevWindow) of the receiving window for the terminal 100 to receive the outbound SLC SDU. The terminal 100 has received the first SLC PDU sent by the Beidou network device 200. However, the first frame parsed by the terminal 100 is not the first SLC PDU in an SLC SDU sent by the Beidou network device 200. The terminal 100 directly replies with a NACK to the Beidou network device. The NACK can be used to indicate that the first frame parsed by the terminal 100 is not the first SLC PDU in an SLC SDU sent by the Beidou network device 200.

[0259] After receiving NACK, the BeiDou network device 200 may no longer send the SLC PDU that has not been sent in the SLC SDU. The BeiDou network device 200 may close the ACK receiving time window of the SLC SDU. The BeiDou network device 200 has not yet sent the third SLC PDU (i.e. Figure 10C The SLC PDU with sequence number 2) and the fourth SLC PDU (i.e. Figure 10C The BeiDou network device 200 can allocate the resources of the unsent SLC PDUs in the SLC SDU to be sent to other users. That is, the BeiDou network device 200 can allocate the resources of the unsent SLC PDUs in the SLC SDU to be sent to other users. Figure 10C The SLC PDU with sequence number 2) and the fourth SLC PDU (i.e. Figure 10C The resources of the SLC PDU (sequence number 3 in the SLC SDU) are allocated to the Beidou network device 200 for use in the SLC SDU to be sent to other users. This can improve the utilization rate of the outbound resources of the Beidou network device 200. The terminal 100 can also enter the low-power process as soon as possible without waiting for other SLC PDUs in the SLC SDU.

[0260] 4. Transmission Mechanism 4

[0261] Beidou network devices have the ability to reclaim and reallocate outbound resources. When Beidou network device 200 sends an SLC SDU to terminal 100, terminal 100 calculates the receive window for the SLC SDU based on the maximum transmission time interval. If terminal 100 successfully receives the SLC SDU within the receive window, it can respond with an ACK to Beidou network device 200.

[0262] Terminal 100 did not receive the last SLC PDU in an SLC SDU sent by Beidou network device 200. Furthermore, the first SLC PDU received, as parsed by terminal 100, was not the first SLC PDU in an SLC SDU sent by Beidou network device 200. Terminal 100 assesses the low likelihood of Beidou network device 200 resource recovery based on the number of received SLC PDUs and does not respond with a NACK. If Beidou network device 200 does not receive a NACK from terminal 100 after the ACK receive window times out (no NACK information is received after tStationEndRcvAck is reached), Beidou network device 200 determines that the SLC SDU transmission has failed and terminates the transmission of this SLC SDU.

[0263] 4.1 Transfer Successful

[0264] The scenario of successful transmission in the fourth transmission mechanism can be the same as the scenario of successful transmission in the third transmission mechanism. The scenario of successful transmission in the fourth transmission mechanism can refer to the above description of the successful transmission scenario. Figure 10A and Figure 10B The description is not repeated here.

[0265] 4.2 Transmission Failure

[0266] Figure 11A A schematic diagram of a transmission failure scenario in a fourth transmission mechanism of the SLC layer when data is outbound provided in an embodiment of the present application is shown.

[0267] like Figure 11A As shown, after sending the first SLC PDU in the SLC SDU, the BeiDou network device 100 starts to calculate the receiving window for the ACK fed back by the receiving terminal 100. The BeiDou network device 200 can send the four SLC PDUs in the SLC SDU at equal intervals in the order of the frame sequence numbers from small to large. The BeiDou network device 200 has sent the first SLC PDU (i.e. Figure 10C The SLC PDU with sequence number 0) and the second SLC PDU (i.e. Figure 10C The SLC PDU with sequence number 1) and the third SLC PDU (i.e. Figure 10C After receiving the first SLC PDU sent by the BeiDou network device 200, the terminal 100 starts an SLC layer receiving session at time t0 and calculates the maximum waiting time (tUeRevWindow) of the receiving window for the terminal 100 to receive the outbound SLC SDU.

[0268] Terminal 100 has received the first SLC PDU sent by Beidou network device 200. However, the first frame parsed by terminal 100 is not the first SLC PDU in an SLC SDU sent by Beidou network device 200. Because Beidou network device 200 has already sent three SLC PDUs in an SLC SDU, the terminal assesses that the likelihood of Beidou network card device 200 reclaiming resources is low. Terminal 100 may not respond with a NACK to the Beidou network device. Beidou network device 200 does not receive a NACK within the ACK receive window and terminates this SLC SDU transmission.

[0269] The following describes an outbound transmission control method in a satellite communication system provided in an embodiment of the present application.

[0270] Figure 11B A flow chart of an outbound transmission control method in a satellite communication system provided in an embodiment of the present application is shown.

[0271] like Figure 11B As shown, the outbound transmission control method in the Beidou communication system includes the following steps:

[0272] S1101. The Beidou network device 200 generates a first user frame to be sent to a first terminal and a second user frame to be sent to a second terminal in a satellite link control layer SLC.

[0273] Among them, the frame header information of the first user frame includes a first user ID field and a first frame type field; the first user ID field is used to indicate the terminal receiving the first user frame; the first user ID field contains the ID information of the first terminal; the first frame type field is used to indicate the frame type of the first user frame; the frame header information of the second user frame includes a second user ID field and a second frame type field; the second user ID field is used to indicate the terminal receiving the second user frame; the second user ID field contains the ID information of the second terminal; the second frame type field is used to indicate the frame type of the second user frame.

[0274] The first user frame includes a satellite link control layer protocol data unit (SLC PDU), an acknowledgment character (ACK) frame, and an application layer receipt frame. The SLC PDU can be used to transmit data, and the acknowledgment character (ACK) frame can be used to indicate whether the Beidou network device has successfully received the terminal's SLC PDU. The application layer receipt frame is used to indicate whether the Beidou network device has successfully parsed the received application layer message.

[0275] S1102 : The Beidou network device 200 generates a first physical frame based on the first user frame and the second user frame at the physical PHY layer.

[0276] S1103 . The Beidou network device 200 sends a first physical frame to the terminal 100 .

[0277] S1104. Terminal 100 receives the first physical frame.

[0278] S1105. The terminal 100 parses the first physical frame to obtain a first user frame.

[0279] The following introduces some possible implementations of the Beidou network device 200.

[0280] In one possible implementation, the first user frame is the first satellite link control layer protocol data unit SLC PDU in the first satellite link control layer service data unit SLCSDU, and the frame header information of the first user frame also includes an acknowledgment mode enable AM ​​enable field, a total number of frames field, and a frame sequence number field; wherein the AM enable field is used to indicate whether the first terminal replies ACK or not; the total number of frames field is used to indicate the number of SLC PDUs sent by the Beidou network device to the first terminal; and the frame sequence number field is used to indicate the sequence number of the SLC PDU sent by the Beidou network device 200.

[0281] The AM enable field of the first SLC PDU has a first value, which is used to indicate that the first terminal does not reply with an ACK. The AM enable field of the first SLC PDU has a second value, which is used to indicate that the first terminal replies with an ACK.

[0282] In this way, the device receiving the first SLC PDU can know whether an ACK reply is required through the frame header information, and does not need to know whether an ACK reply is required through a separate signaling interaction.

[0283] In one possible implementation, the first user frame is the first SLC PDU. After the Beidou network device 200 sends the first physical frame, the method also includes: the Beidou network device 200 continues to send one or more SLC PDUs in the first SLC SDU; after the Beidou network device 200 sends all SLC PDUs in the first SLC SDU, the Beidou network device 200 receives a first ACK sent by the first terminal, and the first ACK is used to indicate that the first terminal successfully receives all SLC PDUs in the first SLC SDU.

[0284] In this way, the Beidou network device 200 can know that the first terminal has successfully received the SLC SDU through the ACK replied by the first terminal. In this way, the Beidou network device 200 continues to send the next SLC SDU.

[0285] In one possible implementation, the first user frame is a first SLC PDU. After the Beidou network device 200 sends the first physical frame, the method further includes: after the Beidou network device 200 sends the first SLC PDU, the Beidou network device 200 receives a second ACK sent by the first terminal, the second ACK being used to indicate that the first terminal did not successfully receive the first SLC PDU; and the Beidou network device 200 allocates resources of one or more SLC PDUs in the first SLC SDU to one or more SLC PDUs in a second SDU sent to the second terminal. In this way, resources of the Beidou network device 200 can be conserved and resource recycling can be achieved.

[0286] In one possible implementation, the first user frame is the first SLC PDU. After the Beidou network device 200 sends the first physical frame, the method also includes: the Beidou network device 200 continues to send one or more SLCPDUs in the first SLC SDU; after the Beidou network device 200 sends all SLC PDUs in the first SLC SDU, the Beidou network device 200 receives a third ACK sent by the first terminal, and the third ACK indicates that the first terminal failed to successfully receive all SLCPDUs in the first SLC SDU.

[0287] In this way, the Beidou network device 200 can determine the next operation based on the ACK replied by the first terminal, for example, end the current transmission.

[0288] In one possible implementation, the frame header information of the first physical frame includes a rate indication field or a version number field; wherein the rate indication field is used to indicate the transmission rate of the first physical frame; and the version number field is used to indicate the current version information of the first physical frame.

[0289] In this way, the device receiving the physical frame can learn the rate and version information of the physical frame.

[0290] In one possible implementation, the first user frame is the first SLC PDU. Before the Beidou network device 200 generates the first user frame to be sent to the first terminal and the second user frame to be sent to the second terminal at the satellite link control layer SLC, the method also includes: the Beidou network device 200 obtains the message data aggregation MDCP layer of the Beidou network device 200 at the satellite link control SLC layer, and multiple satellite link control layer service data units SLC SDUs are sent down, wherein the multiple SLC SDUs include the first SLC SDU; the Beidou network device 200 splits the first SLC SDU into N SLC PDUs at the SLC layer.

[0291] In one possible implementation, before the Beidou network device 200 obtains multiple SLC SDUs sent by the MDCP layer of the Beidou network device 200 at the SLC layer, the method also includes: the Beidou network device 200 obtains the application layer message sent by the application layer of the Beidou network device 200 at the MDCP layer; the Beidou network device 200 uses the application layer message as the MDCP SDU at the MDCP layer, and after adding padding data and a redundant length indication field to the MDCP SDU, splits it into multiple MDCP PDUs; wherein the redundant length indication field is used to indicate the data length of the padding data, the multiple MDCP PDUs include a first MDCP PDU, the header information of the first MDCP PDU includes a subsequent indication field, and the subsequent indication field is used to indicate the order of the first MDCP PDU in the multiple MDCP PDUs; the Beidou network device 200 sends the multiple MDCP PDUs from the MDCP layer to the SLC layer as multiple SLC SDUs of the SLC layer.

[0292] In one possible implementation, before the Beidou network device 200 obtains the application layer message sent by the application layer of the Beidou network device 200 at the MDCP layer, the method also includes: the Beidou network device 200 obtains the original data; the Beidou network device 200 compresses the original data at the application layer to obtain compressed data; the Beidou network device 200 encrypts the compressed data at the application layer to obtain encrypted data; the Beidou network device 200 adds message header information to the encrypted data header to obtain an application layer message; wherein the message header information includes a compression indication field and an encryption indication field, the compression indication field is used to indicate the compression algorithm used when compressing the original data, and the encryption indication field is used to indicate the encryption algorithm used when encrypting the compressed data.

[0293] In one possible implementation, the Beidou network device 200 splits the first SLC SDU into N SLC PDUs at the SLC layer, specifically including: the Beidou network device 200 sends the first SLC PDU and the second SLC PDU among the N SLC PDUs to the PHY layer; the Beidou network device 200 generates a first physical frame from the first SLC PDU and generates a second physical frame from the second SLC PDU at the PHY layer; the Beidou network device 200 sends the first physical frame and the second physical frame.

[0294] In one possible implementation, the Beidou network device 200 sends the first physical frame, including: the Beidou network device 200 adds first check bit information at the end of the first physical frame at the PHY layer, and encodes the first physical frame and the first check bit information to obtain first coded data; the Beidou network device 200 modulates the first coded data and the first reserved field of the first coded data at the PHY layer to obtain first modulated data; the Beidou network device 200 spreads the first modulated data at the PHY layer to obtain first spread spectrum modulated data; the Beidou network device 200 sends the first spread spectrum modulated data and the first pilot information of the first spread spectrum modulated data at the PHY layer.

[0295] In one possible implementation, the method may further include: the Beidou network device 200 determines the starting time of the ACK reception time window based on the time when the Beidou network device 200 sends the last SLC PDU in the first SLC SDU, the processing delay of the first terminal from receiving the last SLC PDU in the first SLC SDU to sending ACK, and the air interface propagation delay; the Beidou network device 200 starts receiving ACK at the starting time of the ACK reception time window.

[0296] In this way, the Beidou network device 200 can determine the starting time of receiving ACK.

[0297] In one possible implementation, the method may further include: the Beidou network device 200 determines the end time of the ACK reception time window based on the time when the Beidou network device 200 sends the last SLC PDU in the first SLC SDU, the processing delay of the first terminal from receiving the last SLC PDU in the first SLC SDU to sending ACK, the time length of the ACK sent by the first terminal, and the air interface propagation delay; the Beidou network device 200 stops receiving ACK at the end time of the ACK reception time window.

[0298] In this way, the Beidou network device 200 can determine the end time of receiving ACK.

[0299] Here, how the Beidou network device specifically determines the start time and end time of receiving ACK can be found in the description above and will not be repeated here.

[0300] Some possible implementations performed by the terminal 100 are described below.

[0301] In one possible implementation, the first user frame is the first satellite link control layer protocol data unit SLC PDU in the first satellite link control layer service data unit SLCSDU, and the frame header information of the first user frame also includes an acknowledgment mode enable AM ​​enable field, a total number of frames field, and a frame sequence number field; wherein the AM enable field is used to indicate whether the terminal 100 replies ACK or not; the total number of frames field is used to indicate the number of SLC PDUs sent by the Beidou network device to the terminal 100; and the frame sequence number field is used to indicate the sequence number of the SLC PDU sent by the Beidou network device.

[0302] The AM enable field of the first SLC PDU has a first value, which is used to instruct the terminal 100 not to reply ACK. The AM enable field of the first SLC PDU has a second value, which is used to instruct the terminal 100 to reply ACK.

[0303] In this way, the terminal 100 receiving the first SLC PDU can know whether it needs to reply ACK through the frame header information, and does not need to know whether it needs to reply ACK through separate signaling interaction.

[0304] In one possible implementation, the first user frame is the first SLC PDU, and the terminal 100 parses the first user frame from the first physical frame. After discarding the second user frame, the method also includes: the terminal 100 receives one or more SLC PDUs in the first SLC SDU; when the terminal 100 receives all SLC PDUs in the first SLC SDU, the terminal 100 sends a first ACK to the Beidou network device, and the first ACK is used to indicate that the terminal 100 successfully receives all SLC PDUs in the first SLC SDU.

[0305] The value of the first ACK can be 1.

[0306] In one possible implementation, the first user frame is the first SLC PDU in the first SLC SDU. The terminal 100 parses the first user frame from the first physical frame, and after discarding the second user frame, the method also includes: when the first SLC PDU parsed by the terminal 100 is not the first SLC PDU in the first SLC SDU; the terminal 100 sends a second ACK to the Beidou network device and stops receiving the second SLC PDU in the first SLC SDU, and the second ACK is used to indicate that the terminal 100 failed to successfully receive the first SLC PDU.

[0307] In one possible implementation, the first user frame is the first SLC PDU in the first SLC SDU. The terminal 100 parses the first user frame from the first physical frame, and after discarding the second user frame, the method also includes: the terminal 100 receives one or more SLC PDUs in the first SLC SDU; when the terminal 100 fails to receive all SLC PDUs in the first SLC SDU within the SLC PDU receiving time window, the terminal 100 sends a third ACK to the Beidou network device, and the third ACK is used to indicate that the terminal 100 has not successfully received all SLC PDUs in the first SLC SDU.

[0308] The values ​​of the second ACK and the third ACK can be 0.

[0309] In one possible implementation, the first user frame is the first SLC PDU in the first SLC SDU, and the terminal 100 parses the first user frame from the first physical frame and discards the second user frame, including: the terminal 100 obtains the first spread spectrum modulated data sent by the terminal at the PHY layer; the terminal 100 despreads the first spread spectrum modulated data at the PHY layer to obtain the first modulated data and the first modulation synchronization header; the terminal 100 demodulates the first modulated data and the first modulation synchronization header at the PHY layer to obtain the first pilot data and the first synchronization header; the terminal 100 removes the pilot information in the first pilot data at the PHY layer to obtain the first coded data; the Beidou network device decodes the first coded data at the PHY layer to obtain the first coded block physical frame and the first verification information; the terminal 100 verifies the first coded block based on the first verification information at the PHY layer, and after the verification is successful, uses the first user frame whose ID field in the first coded block is the same as the ID of the terminal 100 as the first SLC in the first SLC SDU in the SLC layer of the terminal 100. The PDU is presented from the PHY layer to the SLC layer of the terminal 100 .

[0310] In one possible implementation, the terminal 100 verifies the first coding block based on the first verification information at the PHY layer, and after the verification is successful, presents the first user frame in the first coding block whose ID field is the same as the ID of the terminal 100 as the first SLC PDU in the first SLC SDU in the SLC layer of the terminal 100 from the PHY layer to the SLC layer of the terminal 100. The method also includes: the terminal 100 splices the M received SLC PDUs into a first SLC SDU at the SLC layer, and reports the first SLC SDU as the first MDCP PDU of the MDCP layer from the SLC layer of the terminal 100 to the MDCP layer of the terminal 100. The header information of the first MDCP PDU includes a successor indication field, and the successor indication field is used to indicate the order of the first MDCP PDU in multiple MDCP PDUs sent by the Beidou network device.

[0311] In one possible implementation, the method further includes: the terminal 100 obtains, at the MDCP layer, a second MDCP PDU reported from the terminal 100 SLC layer; when the successor indication field in the second MDCP PDU indicates that the second MDCP PDU is the last of multiple MDCP PDUs sent by the Beidou network device, the terminal 100 splices the first MDCP PDU and the second MDCP PDU into an MDCP SDU at the MDCP layer, and reports the MDCP SDU as an application layer message from the MDCP layer to the application layer.

[0312] In one possible implementation, the application layer message includes message header information and encrypted data, the message header information includes an encryption indication field and a compression indication field, the compression indication field is used to indicate the compression algorithm used by the terminal when compressing the original data into compressed data, and the encryption indication field is used to indicate the encryption algorithm used by the terminal when encrypting the compressed data into encrypted data; the method also includes: the terminal 100 decrypts the encrypted data in the application layer message at the application layer through the encryption algorithm indicated by the encryption indication field in the application layer message to obtain compressed data; the terminal 100 decompresses the compressed data at the application layer through the compression algorithm indicated by the compression indication field in the application layer message to obtain the original data.

[0313] In one possible implementation, the method also includes: the terminal 100 determines the time length of the SLC PDU receiving window in the terminal 100 based on the frame sequence number of the received SLC PDU, the time length of the SLC PDU sent by the Beidou network device, the total number of SLC PDU frames in an SLC SDU sent by the Beidou network device, and the sending interval between SLC PDUs.

[0314] In one possible implementation, the method also includes: the terminal 100 determines the time point when the terminal 100 sends the ACK based on the time length of the SLC PDU receiving window, the reception time of the first SLC PDU, the signal processing delay of the terminal 100, and the time length of the ACK sent by the terminal 100.

[0315] The terminal 100 can determine the time length of the SLC PDU receiving window and the time point of sending ACK by referring to the above description, which will not be repeated here.

[0316] After receiving N SLC PDUs in an SLC SDU sent by Beidou network device 200, terminal 100 can determine that Beidou network device 200 requests an ACK based on the AM enable field, total number of frames field, and frame sequence number field in the frame header information of the received SLC PDU, and then respond with an ACK using the parallel acknowledgment mode. Therefore, after the SLC PDU receive window expires, terminal 100 generates an ACK based on the reception results of the N SLC PDUs and returns the ACK to Beidou network device 200. Since the Beidou short message service communication system does not support data retransmission, the ACK sent by terminal 100 does not need to indicate the frame sequence numbers of incomplete SLC PDUs. It only needs to inform Beidou network device 200 whether all N SLC PDUs have been received or not. Therefore, the bitmap portion of the ACK can be 1 bit in length, which is used to indicate whether terminal 100 has received all N SLC PDUs of the current SLC SDU.

[0317] Optionally, in a later evolution version of the BeiDou short message service communication system, the BeiDou network device 200 may also support data retransmission, and the ACK sent by the terminal 100 may also notify the BeiDou network device 200 of the frame sequence numbers that were not received. Therefore, the length of the bitmap portion of the ACK may be N bits, and the N bits are used to indicate whether the terminal 100 has not received the frame sequence numbers of the N SLC PDUs in the current SLC SDU.

[0318] Among them, the terminal 100 can start the SLC SDU session after receiving the first SLC SDU in the SLC SDU. The terminal 100 can determine the remaining time length (tUeRevWindow) of the SLC PDU receiving window on the terminal 100 based on the frame sequence number (nStationRevFrameSN) of the most recently received SLC PDU, the time when the most recently received SLC PDU was received (tUeRevRctSP), the total number of SLC PDU frames in the SLC SDU (nStationTotalFrameNum), the interval (tStationTxInterval) at which the Beidou network device 200 sends the SLC PDU, and the time length (tStationDlFrameLen) of the physical frame sent by the Beidou network device 200.

[0319] The terminal 100 may determine the remaining time length (tUeRevWindow) of the SLC PDU receiving window by the following formula:

[0320] tUeRevWindow=(nStationTotalFrameNum-nStationRevFrameSN-1)*(tStationTxInterval+tStationDlFrameLen)

[0321] In the above formula, the value of tStationTxInterval is preset on the terminal 100. In the above nStationRevFrameSN={0, 1, ..., nStationTotalFrameNum-1}, the value of δ may be 125ms.

[0322] After the SLC PDU reception window ends, the terminal 100 generates an ACK based on the reception results of the N SLC PDUs and returns the ACK to the Beidou network device 200. The terminal 100 can determine the time point (tUeSendAck) at which the terminal 100 sends the ACK based on the air interface propagation delay (tPropagate), the terminal 100's signal processing scheduling delay (tUeProcess), the switching time from the terminal 100's receiving state to the transmitting state (tRx2TxSwitch), and the reception time of the most recent SLC PDU received by the terminal 100 (tUeRevRctSP).

[0323] The terminal 100 may determine the time point (tUeSendAck) at which the terminal 100 sends an ACK by using the following formula:

[0324] tUeSendAck=tUeRevRctSP+tUeRevWindow+tUeProcess+tRx2TxSwitch+Δ

[0325] In the formula, Δ is the physical frame transmission time alignment deviation of the terminal 100.

[0326] The Beidou network device 200 can determine the start time (tStationStartRcvAck) of the ACK receive window (tStationRevAckWindow) and the end time (tStationEndRcvAck) of the ACK receive window based on the time (tStationTxEnd) when the Beidou network device 200 sends the last SLC PDU in the SLC SDU, the air interface propagation delay (tPropagate), the switching time from the receiving state to the sending state of the terminal 100 (tRx2TxSwitch), and the signal processing scheduling delay (tUeProcess) of the terminal 100.

[0327] The Beidou network device 200 can determine the start time (tStationStartRcvAck) of the ACK receiving window (tStationRevAckWindow) by the following formula:

[0328] tStationTxEnd<tStationStartRcvAck<tStationTxEnd+tRx2TxSwitch+2*tPropagate+tUeProcess

[0329] In the above formula, tUeProcess takes the minimum value t_MinUeProc.

[0330] The Beidou network device 200 can determine the end time (tStationEndRcvAck) of the ACK receiving window (tStationRevAckWindow) by the following formula:

[0331] tStationEndRcvAck=tStationTxENd+tUeProcess+tRx2TxSwitch+2*tPropagate+tUeUlFrameLen+Δ

[0332] In the above formula, tUeProcess can take the maximum value t_MaxUeProc.

[0333] The following first introduces the exemplary terminal 100 provided in the embodiment of the present application.

[0334] Figure 12 It is a structural diagram of the terminal 100 provided in an embodiment of the present application.

[0335] The following embodiments are described in detail using terminal 100 as an example. It should be understood that terminal 100 may have more or fewer components than shown in the figure, may combine two or more components, or may have a different component configuration. The various components shown in the figure may be implemented in hardware, including one or more signal processing and / or application-specific integrated circuits, software, or a combination of hardware and software.

[0336] The terminal 100 may include: a processor 110, an external memory interface 120, an internal memory 121, a universal serial bus (USB) interface 130, a charging management module 140, a power management module 141, a battery 142, an antenna 1, an antenna 2, a mobile communication module 150, a wireless communication module 160, an audio module 170, a speaker 170A, a receiver 170B, a microphone 170C, an earphone interface 170D, a sensor module 180, a button 190, a motor 191, an indicator 192, a camera 193, a display screen 194, and a subscriber identification module (SIM) card interface 195, etc. The sensor module 180 may include a pressure sensor 180A, a gyroscope sensor 180B, an air pressure sensor 180C, a magnetic sensor 180D, an acceleration sensor 180E, a distance sensor 180F, a proximity light sensor 180G, a fingerprint sensor 180H, a temperature sensor 180J, a touch sensor 180K, an ambient light sensor 180L, a bone conduction sensor 180M, etc.

[0337] It should be understood that the structure illustrated in the embodiments of the present invention does not constitute a specific limitation on terminal 100. In other embodiments of the present application, terminal 100 may include more or fewer components than shown, or may combine or separate certain components, or arrange the components differently. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0338] The processor 110 may include one or more processing units. For example, the processor 110 may include an application processor (AP), a modem processor, a graphics processing unit (GPU), an image signal processor (ISP), a controller, a memory, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural-network processing unit (NPU). The different processing units may be independent devices or integrated into one or more processors.

[0339] The controller may be the nerve center and command center of the terminal 100. The controller may generate an operation control signal according to the instruction operation code and the timing signal to complete the control of fetching and executing instructions.

[0340] Processor 110 may also include a memory for storing instructions and data. In some embodiments, the memory in processor 110 is a cache memory. This memory can store instructions or data that have just been used or are being recycled by processor 110. If processor 110 needs to use the same instruction or data again, it can directly access the memory. This avoids duplicate accesses, reduces processor 110 latency, and thus improves system efficiency.

[0341] In some embodiments, the processor 110 may include one or more interfaces. The interfaces may include an inter-integrated circuit (I2C) interface, an inter-integrated circuit sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a mobile industry processor interface (MIPI), a general-purpose input / output (GPIO) interface, a subscriber identity module (SIM) interface, and / or a universal serial bus (USB) interface.

[0342] The I2C interface is a bidirectional synchronous serial bus that includes a serial data line (SDA) and a serial clock line (SLC). In some embodiments, the processor 110 may include multiple I2C busses. The processor 110 may be coupled to the touch sensor 180K, the charger, the flash, the camera 193, and the like via different I2C bus interfaces. For example, the processor 110 may be coupled to the touch sensor 180K via the I2C interface, enabling communication between the processor 110 and the touch sensor 180K via the I2C bus interface, thereby implementing the touch function of the terminal 100.

[0343] The I2S interface can be used for audio communication. In some embodiments, the processor 110 can include multiple I2S buses. The processor 110 can be coupled to the audio module 170 via the I2S bus to enable communication between the processor 110 and the audio module 170. In some embodiments, the audio module 170 can transmit audio signals to the wireless communication module 160 via the I2S interface, enabling the function of answering calls through a Bluetooth headset.

[0344] The PCM interface can also be used for audio communication, sampling, quantizing, and encoding analog signals. In some embodiments, the audio module 170 and the wireless communication module 160 can be coupled via a PCM bus interface. In some embodiments, the audio module 170 can also transmit audio signals to the wireless communication module 160 via the PCM interface, enabling the function of answering calls via a Bluetooth headset. Both the I2S interface and the PCM interface can be used for audio communication.

[0345] The UART interface is a universal serial data bus used for asynchronous communication. This bus can be a bidirectional communication bus. It converts the data to be transmitted between serial communication and parallel communication. In some embodiments, the UART interface is typically used to connect the processor 110 and the wireless communication module 160. For example, the processor 110 communicates with the Bluetooth module in the wireless communication module 160 via the UART interface to implement Bluetooth functionality. In some embodiments, the audio module 170 can transmit audio signals to the wireless communication module 160 via the UART interface, enabling the function of playing music through Bluetooth headphones.

[0346] The MIPI interface can be used to connect the processor 110 to peripheral devices such as the display 194 and the camera 193. MIPI interfaces include the camera serial interface (CSI) and the display serial interface (DSI). In some embodiments, the processor 110 and the camera 193 communicate via the CSI interface to implement the camera function of the terminal 100. The processor 110 and the display 194 communicate via the DSI interface to implement the display function of the terminal 100.

[0347] The GPIO interface can be configured via software. The GPIO interface can be configured as either a control signal or a data signal. In some embodiments, the GPIO interface can be used to connect the processor 110 to the camera 193, display 194, wireless communication module 160, audio module 170, sensor module 180, etc. The GPIO interface can also be configured as an I2C interface, an I2S interface, a UART interface, a MIPI interface, etc.

[0348] The SIM interface can be used to communicate with the SIM card interface 195 to implement the function of transmitting data to the SIM card or reading data in the SIM card.

[0349] The USB interface 130 is an interface that complies with USB standards and may be a Mini USB interface, a Micro USB interface, a USB Type-C interface, or the like. The USB interface 130 can be used to connect a charger to charge the terminal 100 and to transfer data between the terminal 100 and peripheral devices. It can also be used to connect headphones to play audio. This interface can also be used to connect other electronic devices, such as augmented reality devices.

[0350] It is understood that the interface connection relationship between the modules illustrated in the embodiment of the present invention is merely an illustrative description and does not constitute a structural limitation on the terminal 100. In other embodiments of the present application, the terminal 100 may also adopt a different interface connection method from the above embodiment, or a combination of multiple interface connection methods.

[0351] The charging management module 140 is configured to receive charging input from a charger, which may be a wireless charger or a wired charger.

[0352] The power management module 141 is used to connect the battery 142, the charging management module 140, and the processor 110. The power management module 141 receives input from the battery 142 and / or the charging management module 140 to provide power to the processor 110, the internal memory 121, the external memory, the display 194, the camera 193, and the wireless communication module 160.

[0353] The wireless communication function of the terminal 100 can be implemented through the antenna 1, the antenna 2, the mobile communication module 150, the wireless communication module 160, the modem processor and the baseband processor.

[0354] Antenna 1 and Antenna 2 are used to transmit and receive electromagnetic wave signals. Each antenna in terminal 100 can be used to cover a single or multiple communication frequency bands. Different antennas can also be reused to improve antenna utilization. For example, antenna 1 can be reused as a diversity antenna for a wireless local area network. In other embodiments, the antennas can be used in conjunction with a tuning switch.

[0355] The mobile communication module 150 can provide solutions for wireless communications including 2G / 3G / 4G / 5G applied on the terminal 100. The mobile communication module 150 may include at least one filter, a switch, a power amplifier, a low noise amplifier (LNA), etc. The mobile communication module 150 can receive electromagnetic waves from the antenna 1, and filter, amplify, and process the received electromagnetic waves, and transmit them to the modulation and demodulation processor for demodulation. The mobile communication module 150 can also amplify the signal modulated by the modulation and demodulation processor, and convert it into electromagnetic waves for radiation through the antenna 1. In some embodiments, at least some of the functional modules of the mobile communication module 150 can be set in the processor 110. In some embodiments, at least some of the functional modules of the mobile communication module 150 can be set in the same device as at least some of the modules of the processor 110.

[0356] The modem processor may include a modulator and a demodulator. The modulator is used to modulate the low-frequency baseband signal to be transmitted into a medium-high frequency signal. The demodulator is used to demodulate the received electromagnetic wave signal into a low-frequency baseband signal. The demodulator then transmits the demodulated low-frequency baseband signal to the baseband processor for processing. After being processed by the baseband processor, the low-frequency baseband signal is passed to the application processor. The application processor outputs a sound signal through an audio device (not limited to the speaker 170A, the receiver 170B, etc.) or displays an image or video through the display screen 194. In some embodiments, the modem processor may be an independent device. In other embodiments, the modem processor may be independent of the processor 110 and be set in the same device as the mobile communication module 150 or other functional modules.

[0357] The wireless communication module 160 can provide wireless communication solutions applied on the terminal 100, including wireless local area networks (WLAN) (such as wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), infrared technology (IR), Beidou communication, etc. The wireless communication module 160 can be one or more devices integrating at least one communication processing module. The wireless communication module 160 receives electromagnetic waves via the antenna 2, frequency modulates and filters the electromagnetic wave signals, and sends the processed signals to the processor 110. The wireless communication module 160 can also receive the signal to be sent from the processor 110, frequency modulate it, amplify it, and convert it into electromagnetic waves for radiation through the antenna 2.

[0358] In some embodiments, the antenna 1 of the terminal 100 is coupled to the mobile communication module 150, and the antenna 2 is coupled to the wireless communication module 160, so that the terminal 100 can communicate with the network and other devices through wireless communication technology. The wireless communication technology may include global system for mobile communications (GSM), general packet radio service (GPRS), code division multiple access (CDMA), wideband code division multiple access (WCDMA), time-division code division multiple access (TD-SCDMA), long term evolution (LTE), BT, GNSS, WLAN, NFC, FM, and / or IR technology, and Beidou communication technology. The GNSS may include a global positioning system (GPS), a global navigation satellite system (GLONASS), a Beidou navigation satellite system (BDS), a quasi-zenith satellite system (QZSS) and / or a satellite based augmentation system (SBAS).

[0359] The terminal 100 can communicate with the Beidou network device 200 via the Beidou communication technology. Optionally, the Beidou communication technology can exist in an independent chip or can be integrated into the wireless communication module 160.

[0360] Terminal 100 implements display functions through a GPU, display screen 194, and an application processor. The GPU is a microprocessor for image processing that connects display screen 194 and the application processor. The GPU is used to perform mathematical and geometric calculations for graphics rendering. Processor 110 may include one or more GPUs that execute program instructions to generate or modify display information.

[0361] Display screen 194 is used to display images, videos, and the like. Display screen 194 includes a display panel. The display panel can be a liquid crystal display (LCD), an organic light-emitting diode (OLED), an active-matrix organic light-emitting diode (AMOLED), a flexible light-emitting diode (FLED), a MiniLED, a MicroLED, a Micro-oLed, or a quantum dot light-emitting diode (QLED). In some embodiments, terminal 100 may include one or N display screens 194, where N is a positive integer greater than one.

[0362] The terminal 100 can realize the shooting function through the ISP, camera 193, video codec, GPU, display screen 194 and application processor.

[0363] The ISP processes data fed back by camera 193. For example, when taking a photo, the shutter is opened, and light is transmitted through the lens to the camera's photosensitive element. The light signal is converted into an electrical signal, which is then passed to the ISP for processing and converted into a visible image. The ISP can also perform algorithmic optimization on image noise, brightness, and skin tone. It can also optimize parameters such as exposure and color temperature of the captured scene. In some embodiments, the ISP can be located within camera 193.

[0364] The camera 193 is used to capture still images or videos. The object generates an optical image through the lens and projects it onto the photosensitive element. The photosensitive element can be a charge coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) phototransistor. The photosensitive element converts the light signal into an electrical signal, and then passes the electrical signal to the ISP for conversion into a digital image signal. The ISP outputs the digital image signal to the DSP for processing. The DSP converts the digital image signal into an image signal in a standard RGB, YUV or other format. In some embodiments, the terminal 100 may include 1 or N cameras 193, where N is a positive integer greater than 1.

[0365] The digital signal processor is used to process digital signals. In addition to processing digital image signals, it can also process other digital signals. For example, when the terminal 100 selects a frequency point, the digital signal processor is used to perform Fourier transform on the frequency point energy.

[0366] Video codecs are used to compress or decompress digital video. Terminal 100 may support one or more video codecs. This allows terminal 100 to play or record videos in various encoding formats, such as Moving Picture Experts Group (MPEG) 1, MPEG2, MPEG3, and MPEG4.

[0367] The NPU is a neural network (NN) computing processor. Drawing on the structure of biological neural networks, such as the transmission patterns between neurons in the human brain, it rapidly processes input information and can continuously self-learn. The NPU enables intelligent cognitive applications in the terminal 100, such as image recognition, face recognition, speech recognition, and text comprehension.

[0368] The internal memory 121 may include one or more random access memories (RAM) and one or more non-volatile memories (NVM).

[0369] Random access memory may include static random-access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM, for example, the fifth generation of DDR SDRAM is generally referred to as DDR5 SDRAM), etc.

[0370] Non-volatile memory may include disk storage devices and flash memory.

[0371] Flash memory can be divided into NOR FLASH, NAND FLASH, 3D NAND FLASH according to the operating principle, single-level cell (SLC), multi-level cell (MLC), triple-level cell (TLC), quad-level cell (QLC) according to the potential level of the storage cell, and universal flash storage (UFS) and embedded multi-media card (eMMC) according to the storage specification.

[0372] The random access memory can be directly read and written by the processor 110, and can be used to store executable programs (such as machine instructions) of the operating system or other running programs, and can also be used to store user and application data.

[0373] The non-volatile memory may also store executable programs and user and application data, etc., and may be loaded into the random access memory in advance for direct reading and writing by the processor 110 .

[0374] The terminal 100 can implement audio functions such as music playback and recording through the audio module 170, the speaker 170A, the receiver 170B, the microphone 170C, the headphone jack 170D, and the application processor.

[0375] The audio module 170 is used to convert digital audio information into analog audio signal output, and is also used to convert analog audio input into digital audio signals. The audio module 170 can also be used to encode and decode audio signals. In some embodiments, the audio module 170 can be provided in the processor 110, or some functional modules of the audio module 170 can be provided in the processor 110.

[0376] The speaker 170A, also called a "speaker", is used to convert audio electrical signals into sound signals. The terminal 100 can listen to music or listen to hands-free calls through the speaker 170A.

[0377] The receiver 170B, also called a "handset", is used to convert audio electrical signals into sound signals. When the terminal 100 receives a call or voice message, the voice can be heard by placing the receiver 170B close to the ear.

[0378] Microphone 170C, also known as "microphone" or "microphone", is used to convert sound signals into electrical signals. When making a call or sending a voice message, the user can speak by putting their mouth close to the microphone 170C to input the sound signal into the microphone 170C. The terminal 100 can be provided with at least one microphone 170C. In other embodiments, the terminal 100 can be provided with two microphones 170C, which can not only collect sound signals but also realize noise reduction function. In other embodiments, the terminal 100 can also be provided with three, four or more microphones 170C to realize sound signal collection, noise reduction, and identification of sound sources, and realize directional recording function, etc.

[0379] The headphone jack 170D is used to connect a wired headphone and can be the USB interface 130 or a 3.5mm open mobile terminal platform (OMTP) standard interface or a cellular telecommunications industry association of the USA (CTIA) standard interface.

[0380] Pressure sensor 180A is used to sense pressure signals and convert them into electrical signals. In some embodiments, pressure sensor 180A can be located on display screen 194. There are many types of pressure sensors 180A, such as resistive, inductive, and capacitive. A capacitive pressure sensor can include at least two parallel plates made of conductive material. When force is applied to pressure sensor 180A, the capacitance between the electrodes changes. Terminal 100 determines the intensity of the pressure based on this change in capacitance. When a touch operation is applied to display screen 194, terminal 100 detects the touch intensity based on pressure sensor 180A. Terminal 100 can also calculate the touch location based on the detection signal from pressure sensor 180A. In some embodiments, touch operations applied to the same touch location but with different touch intensities can correspond to different operation instructions. For example, when a touch operation with an intensity less than a first pressure threshold is applied to a short message application icon, a command to view short messages is executed. When a touch operation with an intensity greater than or equal to the first pressure threshold is applied to a short message application icon, a command to create a new short message is executed.

[0381] The gyroscope sensor 180B can be used to determine the motion posture of the terminal 100. In some embodiments, the angular velocity of the terminal 100 around three axes (i.e., x, y, and z axes) can be determined by the gyroscope sensor 180B. The gyroscope sensor 180B can be used for anti-shake shooting. For example, when the shutter is pressed, the gyroscope sensor 180B detects the angle of the terminal 100 shaking, calculates the distance that the lens module needs to compensate based on the angle, and allows the lens to offset the shaking of the terminal 100 through reverse movement to achieve anti-shake. The gyroscope sensor 180B can also be used for navigation and somatosensory game scenes.

[0382] The air pressure sensor 180C is used to measure air pressure. In some embodiments, the terminal 100 calculates the altitude using the air pressure value measured by the air pressure sensor 180C to assist in positioning and navigation.

[0383] The magnetic sensor 180D includes a Hall sensor. The terminal 100 can use the magnetic sensor 180D to detect the opening and closing of the flip case. In some embodiments, when the terminal 100 is a flip phone, the terminal 100 can detect the opening and closing of the flip cover based on the magnetic sensor 180D. Furthermore, based on the detected opening and closing status of the case or flip cover, features such as automatic unlocking of the flip cover can be configured.

[0384] Accelerometer 180E can detect the magnitude of acceleration of terminal 100 in all directions (generally three axes). When terminal 100 is stationary, it can detect the magnitude and direction of gravity. It can also be used to identify the electronic device's posture, enabling applications such as switching between landscape and portrait modes and pedometers.

[0385] The distance sensor 180F is used to measure distance. The terminal 100 can measure distance using infrared or laser. In some embodiments, when shooting a scene, the terminal 100 can use the distance sensor 180F to measure distance to achieve fast focusing.

[0386] The proximity light sensor 180G may include, for example, a light emitting diode (LED) and a light detector, such as a photodiode. The light emitting diode may be an infrared light emitting diode. The terminal 100 emits infrared light outward through the light emitting diode. The terminal 100 uses the photodiode to detect infrared reflected light from nearby objects. When sufficient reflected light is detected, it can be determined that there is an object near the terminal 100. When insufficient reflected light is detected, the terminal 100 can determine that there is no object near the terminal 100. The terminal 100 can use the proximity light sensor 180G to detect when the user holds the terminal 100 close to the ear to talk, so as to automatically turn off the screen to save power. The proximity light sensor 180G can also be used in leather case mode and pocket mode to automatically unlock and lock the screen.

[0387] Ambient light sensor 180L is used to sense ambient light brightness. Terminal 100 can adaptively adjust the brightness of display screen 194 based on the perceived ambient light brightness. Ambient light sensor 180L can also be used to automatically adjust white balance when taking photos. Ambient light sensor 180L can also work with proximity light sensor 180G to detect whether terminal 100 is in a pocket to prevent accidental touches.

[0388] The fingerprint sensor 180H is used to collect fingerprints. The terminal 100 can use the collected fingerprint characteristics to implement fingerprint unlocking, access application locks, fingerprint photography, fingerprint call answering, etc.

[0389] Temperature sensor 180J is used to detect temperature. In some embodiments, terminal 100 uses the temperature detected by temperature sensor 180J to implement a temperature handling strategy. For example, when the temperature reported by temperature sensor 180J exceeds a threshold, terminal 100 reduces the performance of a processor located near temperature sensor 180J to reduce power consumption and implement thermal protection. In other embodiments, when the temperature falls below another threshold, terminal 100 heats battery 142 to prevent abnormal shutdown of terminal 100 due to low temperature. In other embodiments, when the temperature falls below yet another threshold, terminal 100 boosts the output voltage of battery 142 to prevent abnormal shutdown due to low temperature.

[0390] The touch sensor 180K is also called a "touch panel." The touch sensor 180K can be disposed on the display screen 194. The touch sensor 180K and the display screen 194 form a touch screen, also called a "touch screen." The touch sensor 180K is used to detect touch operations applied thereto or in the vicinity thereof. The touch sensor can transmit the detected touch operations to the application processor to determine the type of touch event. Visual output related to the touch operations can be provided via the display screen 194. In other embodiments, the touch sensor 180K can also be disposed on the surface of the terminal 100, in a location different from that of the display screen 194.

[0391] Keys 190 include a power button, a volume button, etc. Keys 190 may be mechanical keys or touch keys. Terminal 100 may receive key inputs and generate key signal inputs related to user settings and function control of terminal 100.

[0392] Motor 191 can generate vibration prompts. Motor 191 can be used for incoming call vibration prompts, and can also be used for touch vibration feedback. For example, touch operations acting on different applications (such as taking pictures, audio playback, etc.) can correspond to different vibration feedback effects. For touch operations acting on different areas of the display screen 194, motor 191 can also correspond to different vibration feedback effects. Different application scenarios (for example: time reminders, receiving messages, alarm clocks, games, etc.) can also correspond to different vibration feedback effects. The touch vibration feedback effect can also support customization.

[0393] The indicator 192 may be an indicator light, which may be used to indicate the charging status, power level changes, messages, missed calls, notifications, etc.

[0394] The SIM card interface 195 is used to connect a SIM card. The SIM card can be connected to and disconnected from the terminal 100 by inserting or removing it from the SIM card interface 195. The terminal 100 can support one or N SIM card interfaces, where N is a positive integer greater than one. The SIM card interface 195 can support Nano SIM cards, Micro SIM cards, SIM cards, and the like. Multiple cards can be inserted into the same SIM card interface 195 at the same time. The multiple cards can be of the same or different types. The SIM card interface 195 is also compatible with different types of SIM cards. The SIM card interface 195 is also compatible with external memory cards. The terminal 100 interacts with the network through the SIM card to implement functions such as calls and data communications.

[0395] The above content elaborates on the method provided by the present application. In order to facilitate better implementation of the above scheme of the embodiment of the present application, the embodiment of the present application also provides corresponding devices or equipment.

[0396] In the embodiment of the present application, the terminal 100 and the Beidou network device 200 can be divided into functional modules according to the above method example. For example, each functional module can be divided corresponding to each function, or two or more functions can be integrated into one processing module. The above-mentioned integrated modules can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical functional division. There may be other division methods in actual implementation.

[0397] The following will be combined Figures 13 to 16 The communication device according to the embodiment of the present application is described in detail.

[0398] In the case of integrated units, see Figure 13 , Figure 131 is a schematic diagram of the structure of the communication device 1300 provided in the embodiment of the present application. The communication device 1300 may be the terminal 100 in the above embodiment. Optionally, the communication device 1300 may be a chip / chip system, for example, a Beidou communication chip. Figure 13 As shown, the communication device 1300 may include a transceiver unit 1310 and a processing unit 1320 .

[0399] In one design, the transceiver unit 1310 can be used to receive a first physical frame sent by the Beidou network device 200; the first physical frame includes a first user frame sent to the terminal 100 and a second user frame sent to the second terminal, wherein the frame header information of the first user frame includes a first user ID field and a first frame type field; the first user ID field is used to indicate the terminal receiving the first user frame; the first user ID field includes the ID information of the terminal 100; the first user frame is parsed from the first physical frame, and the second user frame is discarded.

[0400] The processing unit 1320 can be used to send a first ACK to the Beidou network device after the terminal 100 receives all SLC PDUs in the first SLC SDU. The first ACK is used to indicate that the terminal 100 successfully receives all SLC PDUs in the first SLC SDU.

[0401] The processing unit 1320 can also be used to, when the first SLC PDU parsed by the terminal 100 is not the first SLC PDU in the first SLC SDU; the terminal 100 sends a second ACK to the Beidou network device and stops receiving the second SLC PDU in the first SLC SDU, and the second ACK is used to indicate that the terminal 100 has not successfully received the first SLC PDU.

[0402] The processing unit 1320 can also be used to send a third ACK to the Beidou network device when the terminal 100 fails to receive all SLC PDUs in the first SLC SDU within the SLC PDU receiving time window. The third ACK is used to indicate that the terminal 100 has not successfully received all SLC PDUs in the first SLC SDU.

[0403] Optionally, the transceiver unit 1310 may also be used to perform the above Figure 11B The terminal 100 in the illustrated method embodiment performs the functional steps related to sending and receiving.

[0404] Optionally, the processing unit 1320 may also be configured to execute the functional steps of protocol parsing and encapsulation and calculation determination performed by the terminal 100 in the method embodiment shown in the above figure.

[0405] It should be understood that the communication device 1300 in this design can execute the method steps executed by the terminal 100 in the aforementioned embodiment. For the sake of brevity, they will not be repeated here.

[0406] In the case of integrated units, see Figure 14 , Figure 14 1 is a structural diagram of the communication device 1400 provided in an embodiment of the present application. The communication device 1400 may be the BeiDou network device 200 in the above embodiment. Optionally, the communication device 1400 may be a specific network element in the BeiDou network device 200, for example, a network element or a combination of multiple network elements in the BeiDou ground transceiver station 22, the BeiDou central station 23, and the BeiDou short message fusion communication platform 24. Figure 14 As shown, the communication device 1400 may include a transceiver unit 1410 and a processing unit 1420 .

[0407] In one design, the transceiver unit 1410 may be configured to generate a first user frame to be sent to the terminal 100 and a second user frame to be sent to the second terminal at the satellite link control layer SLC; generate a first physical frame based on the first user frame and the second user frame at the physical PHY layer; and send the first physical frame.

[0408] Among them, the frame header information of the first user frame includes a first user ID field and a first frame type field; the first user ID field is used to indicate the terminal receiving the first user frame; the first user ID field contains the ID information of the terminal 100; the first frame type field is used to indicate the frame type of the first user frame; the frame header information of the second user frame includes a second user ID field and a second frame type field; the second user ID field is used to indicate the terminal receiving the second user frame; the second user ID field contains the ID information of the second terminal; the second frame type field is used to indicate the frame type of the second user frame.

[0409] Processing unit 1420 can be used to, after the Beidou network device sends the first SLC PDU, receive the second ACK sent by terminal 100, the second ACK is used to indicate that terminal 100 failed to successfully receive the first SLC PDU; the Beidou network device allocates the resources of one or more SLC PDUs in the first SLC SDU to one or more SLC PDUs in the second SDU sent to the second terminal.

[0410] Optionally, the transceiver unit 1410 may also be used to perform the above Figure 11B The Beidou network device 200 in the illustrated method embodiment performs the functional steps related to sending and receiving.

[0411] Optionally, the processing unit 1420 may also be configured to execute the above Figure 11BThe method embodiment shown includes the functional steps of protocol parsing and encapsulation and calculation determination performed by the Beidou network device 200.

[0412] It should be understood that the communication device 1400 in this design can execute the method steps executed by the Beidou network device 200 in the aforementioned embodiment. For the sake of brevity, they will not be repeated here.

[0413] The above describes the terminal 100 and BeiDou network device 200 of the embodiment of the present application. It should be understood that any device having the above Figure 12 Any product having the functions of the terminal 100 as described above Figure 13 Any product that implements the functions of the Beidou network device 200 falls within the protection scope of the embodiments of the present application.

[0414] As a possible product form, the terminal 100 described in the embodiment of the present application can be implemented by a general bus architecture.

[0415] See also Figure 15 , Figure 15 1 is a schematic diagram of the structure of the communication device 1500 provided in an embodiment of the present application. The communication device 1500 may be the terminal 100, or a device therein. Figure 15 As shown, the communication device 1500 includes a processor 1501 and a transceiver 1502 connected to the internal communication of the processor. The processor 1501 can be a general-purpose processor or a dedicated processor. For example, it can be a baseband processor or a central processing unit for satellite communication. The baseband processor for satellite communication can be used to process satellite communication protocols and satellite communication data, and the central processing unit can be used to control the communication device (such as a baseband chip, terminal, terminal chip, etc.), execute computer programs, and process computer program data. The transceiver 1502 can be called a transceiver unit, a transceiver, or a transceiver circuit, etc., and is used to implement transceiver functions. The transceiver 1502 can include a receiver and a transmitter. The receiver can be called a receiver or a receiving circuit, etc., and is used to implement the receiving function; the transmitter can be called a transmitter or a transmitting circuit, etc., and is used to implement the transmitting function. Optionally, the communication device 1500 can also include an antenna 1503 and / or a radio frequency unit (not shown). The antenna 1503 and / or the radio frequency unit may be located inside the communication device 1500 or may be separated from the communication device 1400 , that is, the antenna 1403 and / or the radio frequency unit may be remotely or distributedly deployed.

[0416] Optionally, the communication device 1500 may include one or more memories 1504, on which instructions may be stored. The instructions may be computer programs. The computer programs may be executed on the communication device 1500 to enable the communication device 1500 to perform the methods described in the above method embodiments. Optionally, the memories 1504 may also store data. The communication device 1500 and the memories 1504 may be provided separately or integrated together.

[0417] The processor 1501 , the transceiver 1502 , and the memory 1504 may be connected via a communication bus.

[0418] In one design, the communication device 1500 may be configured to perform the functions of the terminal 100 in the aforementioned embodiment: the processor 1501 may be configured to perform the aforementioned Figure 11B In the embodiment shown, the terminal 100 performs the protocol parsing and encapsulation and the functional steps determined by the operation and / or other processes used in the technology described herein; the transceiver 1502 can be used to perform the above Figure 11B The terminal 100 in the illustrated embodiment performs functional steps related to protocol parsing and encapsulation and computational determination and / or other processes for the technology described herein.

[0419] In any of the above designs, processor 1501 may include a transceiver for implementing receiving and transmitting functions. For example, the transceiver may be a transceiver circuit, an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit for implementing the receiving and transmitting functions may be separate or integrated. The transceiver circuit, interface, or interface circuit may be used for reading and writing code / data, or the transceiver circuit, interface, or interface circuit may be used for transmitting or delivering signals.

[0420] In any of the above designs, processor 1501 may store instructions, which may be computer programs. The computer programs, when executed on processor 1501, may cause communication device 1500 to execute the method steps performed by terminal 100 in the above method embodiments. The computer programs may be embedded in processor 1500, in which case processor 1501 may be implemented by hardware.

[0421] In one implementation, the communication device 1500 may include a circuit that can implement the functions of sending, receiving, or communicating in the aforementioned method embodiments. The processor and transceiver described in this application can be implemented on an integrated circuit (IC), an analog IC, a radio frequency integrated circuit RFIC, a mixed signal IC, an application specific integrated circuit (ASIC), a printed circuit board (PCB), an electronic device, etc. The processor and transceiver can also be manufactured using various IC process technologies, such as complementary metal oxide semiconductor (CMOS), N-type metal oxide semiconductor (nMetal-oxide-semiconductor, NMOS), P-type metal oxide semiconductor (positive channel metal oxide semiconductor, PMOS), bipolar junction transistor (bipolar junction transistor, BJT), bipolar CMOS (BiCMOS), silicon germanium (SiGe), gallium arsenide (GaAs), etc.

[0422] The scope of the communication device described in this application is not limited thereto, and the structure of the communication device may not be limited thereto. Figure 15 The communication device 1500 may be a standalone device or may be part of a larger device. For example, the communication device 1500 may be:

[0423] (1) An independent integrated circuit (IC), or chip, or chip system or subsystem;

[0424] (2) a collection of one or more ICs, optionally including a storage component for storing data and computer programs;

[0425] (3) ASIC, such as modem;

[0426] (4) Modules that can be embedded in other devices;

[0427] (5) Receivers, terminals, smart terminals, cellular phones, wireless devices, handheld devices, mobile units, vehicle-mounted devices, network devices, cloud devices, artificial intelligence devices, etc.;

[0428] (6)Others, etc.

[0429] As a possible product form, any network element in the Beidou network device 200 described in the embodiment of the present application (for example, the Beidou ground transceiver station 22, the Beidou central station 23, the Beidou short message fusion communication platform 24) can be implemented by a general bus architecture.

[0430] See also Figure 16 , Figure 16 1 is a schematic diagram of the structure of the communication device 1600 provided in the embodiment of the present application. The communication device 1600 may be the Beidou network device 200, or a device therein. Figure 16 As shown, the communication device 1600 includes a processor 1601 and a transceiver 1602 connected to the internal communication of the processor. The processor 1601 is a general-purpose processor or a dedicated processor. For example, it can be a baseband processor or a central processing unit for satellite communication. The baseband processor for satellite communication can be used to process satellite communication protocols and satellite communication data, and the central processing unit can be used to control the communication device (such as a baseband chip, etc.), execute computer programs, and process computer program data. The transceiver 1602 can be called a transceiver unit, a transceiver, or a transceiver circuit, etc., for implementing transceiver functions. The transceiver 1602 can include a receiver and a transmitter. The receiver can be called a receiver or a receiving circuit, etc., for implementing a receiving function; the transmitter can be called a transmitter or a transmitting circuit, etc., for implementing a transmitting function. Optionally, the communication device 1600 can also include an antenna 1603 and / or a radio frequency unit (not shown). The antenna 1603 and / or the radio frequency unit may be located inside the communication device 1600 or may be separated from the communication device 1600 , that is, the antenna 1603 and / or the radio frequency unit may be remotely or distributedly deployed.

[0431] Optionally, the communication device 1600 may include one or more memories 1604, on which instructions may be stored. The instructions may be computer programs. The computer programs may be executed on the communication device 1600 to enable the communication device 1600 to perform the methods described in the above method embodiments. Optionally, the memories 1604 may also store data. The communication device 1600 and the memories 1604 may be provided separately or integrated together.

[0432] The processor 1601 , the transceiver 1602 , and the memory 1604 may be connected via a communication bus.

[0433] In one design, the communication device 1600 can be used to perform the functions of the Beidou network device 200 in the above embodiment: the processor 1601 can be used to perform the above Figure 11BIn the embodiment shown, the Beidou network device 200 performs the protocol parsing and encapsulation and the functional steps determined by the operation and / or other processes used in the technology described herein; the transceiver 1602 can be used to perform the above Figure 11B The Beidou network device 200 in the illustrated embodiment performs functional steps related to protocol parsing and encapsulation and computational determination and / or other processes for the technology described herein.

[0434] In any of the above designs, processor 1601 may include a transceiver for implementing receiving and transmitting functions. For example, the transceiver may be a transceiver circuit, an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit for implementing the receiving and transmitting functions may be separate or integrated. The transceiver circuit, interface, or interface circuit may be used for reading and writing code / data, or the transceiver circuit, interface, or interface circuit may be used for transmitting or delivering signals.

[0435] In any of the above designs, processor 1601 may store instructions, which may be computer programs. The computer programs, when executed on processor 1601, may cause communication device 1600 to execute the method steps performed by terminal 100 in the above method embodiments. The computer programs may be fixed in processor 1600, in which case processor 1601 may be implemented by hardware.

[0436] An embodiment of the present application further provides a computer-readable storage medium, in which a computer program code is stored. When the processor executes the computer program code, the communication device executes the method in any of the aforementioned embodiments.

[0437] An embodiment of the present application further provides a computer program product, which, when executed on a computer, enables the computer to execute the method in any of the aforementioned embodiments.

[0438] An embodiment of the present application also provides a communication device, which can exist in the form of a chip product. The structure of the device includes a processor and an interface circuit. The processor is used to communicate with other devices through a receiving circuit, so that the device executes the method in any of the aforementioned embodiments.

[0439] An embodiment of the present application further provides a Beidou communication system, including a terminal 100 and a Beidou network device 200. The terminal 100 and the Beidou network device 200 can execute the method in any of the aforementioned embodiments.

[0440] This application describes the short message communication function of the Beidou communication system. It is understood that other satellite systems may also support short message communication functions. Therefore, the method described in this application is not limited to the Beidou communication system. If other satellite systems also support short message communication functions, the method described in this application is also applicable to communications in other satellite systems.

[0441] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0442] As used in the above embodiments, the term “when…” may be interpreted to mean “if…” or “after…” or “in response to determining…” or “in response to detecting…”, depending on the context. Similarly, the phrases “upon determining…” or “if (stated condition or event) is detected” may be interpreted to mean “if determining…” or “in response to determining…” or “upon detecting (stated condition or event)” or “in response to detecting (stated condition or event)”, depending on the context.

[0443] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state hard disk).

[0444] Those skilled in the art will appreciate that all or part of the process steps in the above-described method embodiments can be implemented by a computer program instructing the relevant hardware. The program can be stored in a computer-readable storage medium, and when executed, the program can include the process steps in the above-described method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM or random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A method for controlling outbound transmission in a satellite communication system, characterized in that: include: A satellite network device generates a first user frame to be sent to a first terminal and a second user frame to be sent to a second terminal at a satellite link control (SLC) layer; wherein the frame header information of the first user frame includes a first user ID field and a first frame type field; the first user ID field is used to indicate a terminal receiving the first user frame; the first user ID field contains ID information of the first terminal; the first frame type field is used to indicate a frame type of the first user frame; the first user frame includes a satellite link control layer protocol data unit (SLC) PDU, an acknowledgment character (ACK) frame, and an application layer receipt frame; the application layer receipt frame is used to indicate whether the satellite network device has successfully parsed a received application layer message; the frame header information of the second user frame includes a second user ID field and a second frame type field; the second user ID field is used to indicate a terminal receiving the second user frame; the second user ID field contains ID information of the second terminal; and the second frame type field is used to indicate a frame type of the second user frame. The satellite network device generates a first physical frame based on the first user frame and the second user frame at a physical PHY layer; The satellite network device sends the first physical frame.

2. The method according to claim 1, characterized in that The first user frame is the first satellite link control layer protocol data unit SLC PDU in the first satellite link control layer service data unit SLC SDU, and the frame header information of the first user frame also includes an acknowledgment mode enable AM ​​enable field, a total number of frames field, and a frame sequence number field; wherein the AMenable field is used to indicate whether the first terminal replies ACK or not; the total number of frames field is used to indicate the number of SLC PDUs sent by the satellite network device to the first terminal; and the frame sequence number field is used to indicate the sequence number of the SLC PDU sent by the satellite network device.

3. The method according to claim 2, characterized in that The AM enable field of the first SLC PDU is a first value, and the first value is used to indicate that the first terminal does not reply to ACK.

4. The method according to claim 2, characterized in that The AM enable field of the first SLC PDU is a second value, and the second value is used to instruct the first terminal to reply with ACK.

5. The method according to claim 4, characterized in that The first user frame is the first SLC PDU. After the satellite network device sends the first physical frame, the method further includes: The satellite network device continues to send one or more SLC PDUs in the first SLC SDU; After the satellite network device sends all SLC PDUs in the first SLC SDU, the satellite network device receives a first ACK sent by the first terminal, where the first ACK is used to indicate that the first terminal successfully receives all SLC PDUs in the first SLC SDU.

6. The method according to claim 4, characterized in that The first user frame is the first SLC PDU. After the satellite network device sends the first physical frame, the method further includes: After the satellite network device completes sending the first SLC PDU, the satellite network device receives a second ACK sent by the first terminal, where the second ACK is used to indicate that the first terminal has not successfully received the first SLC PDU; The satellite network device allocates resources of one or more SLC PDUs in the first SLC SDU to one or more SLC PDUs in a second SDU sent to the second terminal.

7. The method according to claim 4, characterized in that The first user frame is the first SLC PDU. After the satellite network device sends the first physical frame, the method further includes: The satellite network device continues to send one or more SLC PDUs in the first SLC SDU; After the satellite network device sends all SLC PDUs in the first SLC SDU, the satellite network device receives a third ACK sent by the first terminal, where the third ACK indicates that the first terminal has not successfully received all SLC PDUs in the first SLC SDU.

8. The method according to any one of claims 1 to 7, characterized in that The frame header information of the first physical frame includes a rate indication field or a version number field; wherein the rate indication field is used to indicate the transmission rate of the first physical frame; and the version number field is used to indicate the current version information of the first physical frame.

9. The method according to claim 2, characterized in that The first user frame is the first SLC PDU. Before the satellite network device generates, in a satellite link control layer SLC, a first user frame to be sent to the first terminal and a second user frame to be sent to the second terminal, the method further includes: The satellite network device obtains, at a satellite link control SLC layer, a plurality of satellite link control layer service data units (SLC SDUs) issued by a message data convergence MDCP layer of the satellite network device, wherein the plurality of SLC SDUs includes the first SLC SDU; The satellite network device splits the first SLC SDU into N SLC PDUs at the SLC layer.

10. The method according to claim 9, characterized in that Before the satellite network device obtains, at the SLC layer, a plurality of SLC SDUs issued by the MDCP layer of the satellite network device, the method further includes: The satellite network device obtains, at the MDCP layer, an application layer message sent by the application layer of the satellite network device; The satellite network device uses the application layer message as an MDCP SDU at the MDCP layer, and after adding padding data and a redundant length indication field to the MDCP SDU, splits the message into multiple MDCP PDUs; wherein the redundant length indication field is used to indicate a data length of the padding data, the multiple MDCP PDUs include a first MDCP PDU, and the header information of the first MDCP PDU includes a subsequent indication field, and the subsequent indication field is used to indicate an order of the first MDCP PDU in the multiple MDCP PDUs; The satellite network device sends the multiple MDCP PDUs from the MDCP layer to the SLC layer as the multiple SLC SDUs of the SLC layer.

11. The method according to claim 10, characterized in that Before the satellite network device obtains, at the MDCP layer, an application layer message sent by the application layer of the satellite network device, the method further includes: The satellite network device acquires raw data; The satellite network device compresses the original data at the application layer to obtain compressed data; The satellite network device encrypts the compressed data at the application layer to obtain encrypted data; The satellite network device adds message header information to the encrypted data header to obtain the application layer message; wherein the message header information includes a compression indication field and an encryption indication field, the compression indication field is used to indicate the compression algorithm used when compressing the original data, and the encryption indication field is used to indicate the encryption algorithm used when encrypting the compressed data.

12. The method according to claim 11, characterized in that The satellite network device splits the first SLC SDU into N SLC PDUs at the SLC layer, specifically including: The satellite network device sends the first SLC PDU and the second SLC PDU of the N SLC PDUs to the PHY layer; The satellite network device generates a first physical frame from the first SLC PDU and generates a second physical frame from the second SLC PDU at the PHY layer; The satellite network device sends the first physical frame and the second physical frame.

13. The method according to claim 12, characterized in that The satellite network device sending the first physical frame includes: The satellite network device adds first check bit information to the end of the first physical frame at the PHY layer, and encodes the first physical frame and the first check bit information to obtain first encoded data; The satellite network device modulates the first coded data and the first reserved field of the first coded data at the PHY layer to obtain first modulated data; The satellite network device performs spectrum spreading on the first modulated data at the PHY layer to obtain first spread spectrum modulated data; The satellite network device transmits the first spread spectrum modulated data and first pilot information of the first spread spectrum modulated data at the PHY layer.

14. The method according to claim 2, characterized in that The method may further comprise: The satellite network device determines, based on the time when the satellite network device completes sending the last SLC PDU in the first SLC SDU, a processing scheduling delay from the first terminal completing receiving the last SLC PDU in the first SLC SDU to sending an ACK, a switching time length from a receiving state to a sending state of the first terminal, and an air interface propagation delay, a starting time of the ACK receiving time window; The satellite network device starts receiving ACK at the start time of the ACK reception time window.

15. The method according to any one of claims 9 to 14, characterized in that: The method may further comprise: The satellite network device determines, based on a time point at which the satellite network device completes sending the last SLC PDU in the first SLC SDU, a processing delay from when the first terminal completes receiving the last SLC PDU in the first SLC SDU to when it sends an ACK, a time length of the ACK sent by the first terminal, a switching time length from a receiving state to a sending state of the first terminal, and an air interface propagation delay, an end time point of the ACK receiving time window; The satellite network device stops receiving ACK at the end of the ACK reception time window.

16. A method for controlling outbound transmission in a satellite communication system, characterized in that: include: The first terminal receives a first physical frame sent by the satellite network device; The first physical frame includes a first user frame sent to the first terminal and a second user frame sent to the second terminal, wherein frame header information of the first user frame includes a first user ID field and a first frame type field; the first user ID field is used to indicate a terminal receiving the first user frame; the first user ID field includes ID information of the first terminal; the first user frame includes a satellite link control layer protocol data unit (SLC PDU), an acknowledgment character (ACK) frame, and an application layer receipt frame, wherein the application layer receipt frame is used to indicate whether the satellite network device successfully parses the received application layer message; The first terminal parses the first user frame from the first physical frame and discards the second user frame.

17. The method according to claim 16, characterized in that The first user frame is the first satellite link control layer protocol data unit SLC PDU in the first satellite link control layer service data unit SLC SDU, and the frame header information of the first user frame also includes an acknowledgment mode enable AM ​​enable field, a total number of frames field, and a frame sequence number field; wherein the AMenable field is used to indicate whether the first terminal replies ACK or not; the total number of frames field is used to indicate the number of SLC PDUs sent by the satellite network device to the first terminal; and the frame sequence number field is used to indicate the sequence number of the SLC PDU sent by the satellite network device.

18. The method according to claim 17, characterized in that The AM enable field of the first SLC PDU is a first value, and the first value is used to indicate that the first terminal does not reply to ACK.

19. The method according to claim 17, wherein The AM enable field of the first SLC PDU is a second value, and the second value is used to instruct the first terminal to reply with ACK.

20. The method according to any one of claims 16 to 19, characterized in that: The first user frame is a first SLCPDU, the first terminal parses the first user frame from the first physical frame, and after discarding the second user frame, the method further includes: The first terminal receives one or more SLC PDUs in the first SLC SDU; After the first terminal receives all the SLC PDUs in the first SLC SDU, the first terminal sends a first ACK to the satellite network device, where the first ACK is used to indicate that the first terminal successfully receives all the SLC PDUs in the first SLC SDU.

21. The method according to any one of claims 16 to 19, characterized in that: The first user frame is a first SLC PDU in a first SLC SDU, the first terminal parses the first user frame from the first physical frame, and after discarding the second user frame, the method further includes: When the first SLC PDU parsed by the first terminal is not the first SLC PDU in the first SLC SDU; the first terminal sends a second ACK to the satellite network device and stops receiving the second SLC PDU in the first SLC SDU, and the second ACK is used to indicate that the first terminal has not successfully received the first SLC PDU.

22. The method according to any one of claims 16 to 19, characterized in that: The first user frame is a first SLC PDU in a first SLC SDU, the first terminal parses the first user frame from the first physical frame, and after discarding the second user frame, the method further includes: The first terminal receives one or more SLC PDUs in the first SLC SDU; When the first terminal fails to receive all SLC PDUs in the first SLC SDU within the SLC PDU receiving time window, the first terminal sends a third ACK to the satellite network device, where the third ACK is used to indicate that the first terminal has failed to successfully receive all SLC PDUs in the first SLC SDU.

23. The method according to claim 16, wherein The first user frame is a first SLC PDU in a first SLC SDU, and the first terminal parses the first user frame from the first physical frame and discards the second user frame, including: The first terminal obtains, at a physical PHY layer, first spread spectrum modulated data sent by the terminal; The first terminal despreads the first spread spectrum modulated data at the PHY layer to obtain first modulated data and a first modulation synchronization header; The first terminal demodulates the first modulated data and the first modulated synchronization header at the PHY layer to obtain first pilot data and a first synchronization header; The first terminal removes pilot information from the first pilot data at the PHY layer to obtain first coded data; The satellite network device decodes the first coded data at the PHY layer to obtain a first coded block physical frame and first check information; The first terminal verifies the first coding block based on the first verification information at the PHY layer, and after the verification is successful, presents the first user frame in the first coding block whose ID field is the same as the first terminal ID as the first SLC PDU in the first SLC SDU in the SLC layer of the first terminal from the PHY layer to the SLC layer of the first terminal.

24. The method according to claim 23, wherein The first terminal verifies the first coding block based on the first verification information at the PHY layer, and after the verification succeeds, presents the first user frame in the first coding block whose ID field is the same as the first terminal ID as the first SLC PDU in the first SLC SDU in the SLC layer of the first terminal from the PHY layer to the SLC layer of the first terminal, the method further comprising: The first terminal splices the M received SLC PDUs into the first SLC SDU at the SLC layer, and reports the first SLC SDU as the first MDCP PDU of the MDCP layer from the SLC layer of the first terminal to the MDCP layer of the first terminal, where the header information of the first MDCP PDU includes a successor indication field, and the successor indication field is used to indicate the order of the first MDCP PDU in multiple MDCP PDUs sent by the satellite network device.

25. The method according to claim 24, characterized in that The method further comprises: The first terminal obtains, at the MDCP layer, a second MDCP PDU reported from the SLC layer of the first terminal; When the successor indication field in the second MDCP PDU indicates that the second MDCP PDU is the last one of multiple MDCP PDUs sent by the satellite network device, the first terminal splices the first MDCP PDU and the second MDCP PDU into an MDCP SDU at the MDCP layer, and reports the MDCP SDU from the MDCP layer to the application layer as an application layer message.

26. The method according to claim 25, characterized in that The application layer message includes message header information and encrypted data, the message header information includes an encryption indication field and a compression indication field, the compression indication field is used to indicate the compression algorithm used by the terminal when compressing original data into compressed data, and the encryption indication field is used to indicate the encryption algorithm used by the terminal when encrypting the compressed data into encrypted data; The method further comprises: The first terminal decrypts the encrypted data in the application layer message at the application layer using an encryption algorithm indicated by an encryption indication field in the application layer message to obtain the compressed data; The first terminal decompresses the compressed data at the application layer using a compression algorithm indicated by a compression indication field in the application layer message to obtain the original data.

27. The method according to any one of claims 23 to 26, characterized in that The method further comprises: The first terminal determines the remaining time length of the SLC PDU receiving window in the first terminal based on the frame sequence number of the currently received SLC PDU, the time of the currently received SLC PDU, the time length of the physical frame sent by the satellite network device, the total number of SLC PDU frames in an SLC SDU sent by the satellite network device, and the sending interval between SLC PDUs.

28. The method according to claim 27, characterized in that The method further comprises: The first terminal determines the time point when the first terminal sends the ACK based on the time length of the SLC PDU receiving window, the reception time of the first SLC PDU, the signal processing delay of the first terminal, and the time length of the ACK sent by the first terminal.

29. A satellite communication system, characterized in that: It includes a first terminal and a satellite network device; wherein, The satellite network device is used to generate a first user frame sent to a first terminal and a second user frame sent to a second terminal at a satellite link control layer (SLC); wherein the frame header information of the first user frame includes a first user ID field and a first frame type field; the first user ID field is used to indicate a terminal receiving the first user frame; the first user ID field contains ID information of the first terminal; the first frame type field is used to indicate a frame type of the first user frame; the frame header information of the second user frame includes a second user ID field and a second frame type field; the second user ID field is used to indicate a terminal receiving the second user frame; the second user ID field contains ID information of the second terminal; and the second frame type field is used to indicate a frame type of the second user frame; The satellite network device is configured to generate a first physical frame based on the first user frame and the second user frame at a physical PHY layer; The satellite network device is used to send the first physical frame; The first terminal is used to receive a first physical frame sent by a satellite network device; parse the first user frame from the first physical frame, and discard the second user frame.

30. A communication device, characterized in that: The communication device comprises one or more processors, one or more memories and a transceiver; wherein the transceiver and the one or more memories are coupled to the one or more processors, the one or more memories are used to store computer program code, and the computer program code includes computer instructions. When the one or more processors execute the computer instructions, the communication device executes the method according to any one of claims 1 to 15.

31. The communication device according to claim 30, wherein: The communication device is a satellite network device.

32. A communication device, characterized in that: The communication device comprises one or more processors, one or more memories, and a transceiver; wherein the transceiver and the one or more memories are coupled to the one or more processors, the one or more memories are used to store computer program code, and the computer program code includes computer instructions. When the one or more processors execute the computer instructions, the communication device executes the method according to any one of claims 16 to 28.

33. The communication device according to claim 32, wherein: The communication device is a terminal.

34. A computer-readable storage medium, wherein instructions are stored in the computer-readable storage medium, and when the instructions are executed on a computer, the computer is caused to execute the method according to any one of claims 1 to 15.

35. A computer-readable storage medium, wherein instructions are stored in the computer-readable storage medium. When the instructions are executed on a computer, the computer is caused to execute the method according to any one of claims 16 to 28.

36. A chip system, applied to a terminal, characterized in that: The method comprises a processing circuit and an interface circuit, wherein the interface circuit is used to receive code instructions and transmit the code instructions to the processing circuit, and the processing circuit is used to run the code instructions to execute the method according to any one of claims 16 to 28.

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