Data transmission control method and system in Beidou communication system and related device

Abstract

The invention discloses a data transmission control method and system in a Beidou communication system and a related device. In the method, a terminal can split an MDCP SDU of an MDCP layer into one or more MDCP segment data with a fixed length, and add a subsequent indication field to the head of each MDCP segment data to obtain an MDCP PDU, the subsequent indication field can be used for representing that the current MDCP PDU is a start frame, a middle frame or a last frame in continuously sent frames; or a frame sent separately. A terminal may send one or more MDCP PDUs to a Beidou network device. The Beidou network device can combine a plurality of MDCP PDUs into one MDCP SDU according to the subsequent indication field in the MDCP PDUs. By implementing the method, the terminal can reliably transmit data to the Beidou network equipment under the constraint of a Beidou communication system and a limited rate.

Description

[0001] This application is a divisional application. The application number of the original application is 202110877288.0, and the original application date is July 31, 2021. The entire contents of the original application are incorporated into this application by reference. Technical Field

[0002] The present application relates to the field of satellite communications, and in particular to a data transmission control method, system and related devices in a Beidou communication system. Background Art

[0003] The BeiDou satellite navigation system is a major infrastructure independently developed by my country that integrates positioning, timing and communication. The BeiDou short message communication service is one of the characteristics of the BeiDou satellite navigation system that distinguishes it from other global navigation systems such as the US GPS, Russia's GLONASS, and Europe's GALILEO. The BeiDou short message communication service is particularly suitable for communication in areas such as oceans, deserts, grasslands, and uninhabited areas where mobile communications are not covered, or cannot be covered, or where the communication system is damaged. The short message system of the BeiDou-3 satellite has upgraded the short message technology system and achieved the separation of military and civilian signals. On the premise of ensuring that military needs are fully met, the state has opened some necessary resources of the BeiDou short message system to civilian use. In view of the characteristics of civilian services and equipment, it is necessary to design communication protocols based on the characteristics of the BeiDou short message system.

[0004] Since the communication system of Beidou short message service communicates through satellite link, its main characteristics are: 1. Long delay; 2. Large link loss; 3. The supported services are mainly burst short message services; 4. Link state management, mobility management and broadcast control information are not supported. The current wireless communication protocol cannot be applied to the communication system of Beidou short message service. The reason is that due to the long propagation distance of satellite communication, the communication system of Beidou short message service requires high terminal transmission power. In addition, the limitation of radio frequency capability of civil terminals causes the inbound rate to be much lower than that of dedicated terminals. Therefore, it is necessary to design a data transmission process in detail to reduce signaling overhead and invalid transmission under the constraints of Beidou communication system and rate limitation, so as to achieve reliable and orderly data transmission. Summary of the invention

[0005] The present application provides a data transmission control method, system and related devices in a Beidou communication system. Through the method provided by the present application, under the constraints of the Beidou communication system and rate limitation, the terminal can reduce signaling overhead and reduce invalid transmission, thereby achieving reliable and orderly data transmission.

[0006] In a first aspect, the present application provides a data transmission control method in a Beidou communication system, which may include: after the terminal adds padding data and a redundant length indication field to the first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer, it is divided into M data convergence layer service protocol data units MDCP PDU, where M is a positive integer; wherein the redundant length indication field is used to indicate the data length of the padding data, the M 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 M MDCP PDUs; the terminal sends the first MDCP PDU to a Beidou network device.

[0007] In this way, under the constraints of the Beidou communication system and rate limitations, the terminal can also reliably transmit data to the Beidou network equipment.

[0008] Among them, in one possible implementation, M is greater than 1, the successor indication field of the first MDCP PDU is a first value, and the first value is used to indicate that the first MDCP PDU is the first MDCP PDU among M MDCP PDUs; M is greater than 1, the successor indication field of the first MDCP PDU is a second value, and the second value is used to indicate that the first MDCP PDU is the middle MDCP PDU among the M MDCP PDUs; M is greater than 1, the successor indication field of the first MDCP PDU is a third value, and the third value is used to indicate that the first MDCP PDU is the last MDCP PDU among the M MDCP PDUs.

[0009] In a possible implementation manner, M is 1, and the successor indication field of the first MDCP PDU is a fourth value, and the fourth value is used to indicate that the first MDCP PDU is a separate MDCP PDU.

[0010] In this way, the terminal divides the data packet at the MDCP layer, and can still effectively transmit data under the constraints of the Beidou communication system and rate limitation. The header information of the MDCP PDU includes a subsequent indication field, which is used to indicate the order of the first MDCP PDU in the M MDCP PDUs. The device receiving the MDCP PDU can know whether the received MDCP PDU is incorrect based on the subsequent indication field. In this way, signaling overhead and invalid transmission can be reduced.

[0011] In a possible implementation manner, after the terminal adds padding data and a redundant length indication field to the first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer, the first message data convergence layer service data unit MDCP SDU is divided into M data convergence layer service protocol data units MDCP PDU, specifically including: the terminal generates an application layer message at the application layer; the terminal uses the application layer message as the first MDCP SDU at the MDCP layer, and after the padding data and the redundant length indication field are added to the first MDCP SDU, the first MDCP SDU is divided into M MDCP PDUs.

[0012] In a possible implementation, the terminal uses the application layer message as the first MDCP SDU at the MDCP layer, and after adding padding data and a redundant length indication field to the first MDCP SDU and before dividing it into M MDCP PDUs, the method further includes: the terminal obtains original data; the terminal compresses the original data at the application layer to obtain compressed data; the terminal encrypts the compressed data at the application layer to obtain encrypted data; the terminal 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.

[0013] In a possible implementation, the terminal sends the first MDCP PDU to the Beidou network device, specifically including: the terminal transmits the first MDCP PDU to the satellite link control SLC layer as the first satellite link control layer service data unit SLC SDU of the SLC layer; the terminal divides the first SLC SDU into N satellite link control layer protocol data units SLCPDU at the SLC layer, where N is a positive integer; wherein the N SLC PDUs include the first SLC PDU, and the frame header information of the first SLC PDU includes a service data unit alternation indication SAI field, a total number of frames field, and a frame sequence number field; the SAI field is used to indicate whether the first SLC PDU is retransmission data, the total number of frames field is used to indicate the total number N of SLC PDUs included in the first SLC SDU, and the frame sequence number field is used to indicate the frame sequence number of the first SLC PDU in the first SLC SDU; the terminal sends the first SLC PDU to the Beidou network device.

[0014] In this way, whether the SLC PDU is retransmitted data is indicated by flipping the value of the SAI field of the SLC PDU, which can ensure that the Beidou network device can identify whether the received SLC PDU is retransmitted data, thereby ensuring continuous data transmission in the Beidou communication system.

[0015] In a possible implementation, the terminal sends the first SLC PDU to the Beidou network device, specifically including: the terminal sends the first SLC PDU from the SLC layer to the physical PHY layer as the first coding block of the PHY layer; the terminal adds check bit information at the end of the first coding block at the PHY layer, and encodes the first coding block and the check bit information to obtain first coded data; the terminal inserts pilot information into the first coded data at the PHY layer to obtain first pilot data; the terminal modulates the first pilot data and the synchronization header of the first pilot data at the PHY layer to obtain first modulated data and a first modulation synchronization header; the terminal spreads the first modulated data and the modulation synchronization header at the PHY layer to obtain first spread spectrum modulated data; the terminal sends the first spread spectrum modulated data as the first physical frame to the Beidou network device at the PHY layer.

[0016] In a possible implementation manner, the terminal determines the data length of the first MDCP PDU according to the data length of the first MDCP SDU and the data length of the first physical frame.

[0017] In this way, the terminal can know how to split the MDCP SDU into multiple MDCP PDUs.

[0018] In a second aspect, a data transmission control method in a Beidou communication system is provided, which may include: a Beidou network device receives M data convergence layer service protocol data units MDCP PDUs sent by a terminal, where M is a positive integer; wherein the M MDCP PDUs include a first MDCP PDU, and the header information of the first MDCP PDU includes a successor indication field, which is used to indicate the order of the first MDCP PDU in the M MDCP PDUs; the Beidou network device splices the M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer.

[0019] In this way, data can be reliably transmitted between Beidou network devices and terminals under the constraints of the Beidou communication system and rate limitations.

[0020] Among them, in one possible implementation, M is greater than 1, the successor indication field of the first MDCP PDU is a first value, and the first value is used to indicate that the first MDCP PDU is the first MDCP PDU among M MDCP PDUs; M is greater than 1, the successor indication field of the first MDCP PDU is a second value, and the second value is used to indicate that the first MDCP PDU is the middle MDCP PDU among the M MDCP PDUs; M is greater than 1, the successor indication field of the first MDCP PDU is a third value, and the third value is used to indicate that the first MDCP PDU is the last MDCP PDU among the M MDCP PDUs.

[0021] In a possible implementation manner, M is 1, and the successor indication field of the first MDCP PDU is a fourth value, and the fourth value is used to indicate that the first MDCP PDU is a separate MDCP PDU.

[0022] In this way, the Beidou network device can accurately splice multiple MDCP PDUs into an MDCP SDU according to the order of the MDCP PDU in multiple MDCP PDUs indicated by the successor indication field in the MDCP PDU.

[0023] In a possible implementation, the Beidou network device splices the M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer, including: when the second MDCP PDU received by the Beidou network device subsequently indicates that the second MDCP PDU is the last one of the M MDCP PDUs, the Beidou network device splices the M MDCP PDUs into a first MDCP SDU at the MDCP layer, and reports the first MDCP SDU as an application layer message from the MDCP layer to the application layer.

[0024] 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 original data into compressed data, and the encryption indication field is used to indicate the encryption algorithm used by the terminal when encrypting compressed data into encrypted data; the method also includes: the Beidou network device 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 Beidou network device 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.

[0025] In a possible implementation, it also includes: the Beidou network device splices N SLC PDUs into a first SLC SDU at the SLC layer, and reports the first SLC SDU as the first MDCP PDU from the SLC layer of the Beidou network device to the MDCP layer of the Beidou network device; wherein the N SLC PDUs include the first SLC PDU, and the frame header information of the first SLC PDU includes a service data unit alternating indication SAI field, a total number of frames field, and a frame sequence number field; the SAI field is used to indicate whether the first SLC PDU is retransmitted data, the total number of frames field is used to indicate the total number N of SLC PDUs included in the first SLC SDU, and the frame sequence number field is used to indicate the frame sequence number of the first SLC PDU in the first SLC SDU.

[0026] In a possible implementation, the Beidou network device splices N SLC PDUs into a first SLC SDU at the SLC layer, and reports the first SLC SDU as the first MDCP PDU from the SLC layer of the Beidou network device to the MDCP layer of the Beidou network device. The method also includes: the Beidou network device obtains the first spread spectrum modulation data sent by the terminal at the PHY layer; the Beidou network device despreads the first spread spectrum modulation data at the PHY layer to obtain the first modulation data and the first modulation synchronization header; the Beidou network device demodulates the first modulation data and the first modulation synchronization header at the PHY layer to obtain the first pilot data and the first synchronization header; the Beidou network device 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 and the first verification information; the Beidou network device verifies the first coded block based on the first verification information at the PHY layer, and after the verification is successful, uses the first coded block as the first SLC in the first SLC SDU in the SLC layer of the Beidou network device. The PDU is presented from the PHY layer to the SLC layer of the Beidou network device.

[0027] In a possible implementation, the Beidou network device splices M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer, including: after the Beidou network device removes the successor indication field of each MDCP PDU in the M MDCP PDUs at the MDCP layer, the M MDCP PDUs are spliced ​​into a first MDCP SDU in the order indicated by the successor indication of each MDCP PDU in the M MDCP PDUs.

[0028] In a third aspect, a data transmission control method in a Beidou communication system is provided, the method may include: the Beidou network device divides a first message data convergence layer service data unit MDCP SDU into M data convergence layer service protocol data units MDCP PDU at the message data convergence MDCP layer, where M is a positive integer; wherein the M MDCP PDUs include a first MDCP PDU, and 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 M MDCP PDUs; the Beidou network device sends the first MDCP PDU.

[0029] In this way, data can be reliably transmitted between Beidou network devices and terminals under the constraints of the Beidou communication system and rate limitations.

[0030] Among them, in one possible implementation, M is greater than 1, the successor indication field of the first MDCP PDU is a first value, and the first value is used to indicate that the first MDCP PDU is the first MDCP PDU among M MDCP PDUs; M is greater than 1, the successor indication field of the first MDCP PDU is a second value, and the second value is used to indicate that the first MDCP PDU is the middle MDCP PDU among the M MDCP PDUs; M is greater than 1, the successor indication field of the first MDCP PDU is a third value, and the third value is used to indicate that the first MDCP PDU is the last MDCP PDU among the M MDCP PDUs.

[0031] In a possible implementation manner, M is 1, and the successor indication field of the first MDCP PDU is a fourth value, and the fourth value is used to indicate that the first MDCP PDU is a separate MDCP PDU.

[0032] In this way, the Beidou network device divides the data packet at the MDCP layer, and can still effectively transmit data under the constraints of the Beidou communication system and rate limit. The header information of the MDCP PDU includes a subsequent indication field, which is used to indicate the order of the first MDCP PDU in the M MDCP PDUs. The device receiving the MDCP PDU can know whether the received MDCP PDU is incorrect according to the subsequent indication field. In this way, signaling overhead and invalid transmission can be reduced.

[0033] In a possible implementation, the Beidou network device divides the first message data convergence layer service data unit MDCP SDU into M data convergence layer service protocol data units MDCP PDU at the message data convergence MDCP layer, specifically including: the Beidou network device generates an application layer message at the application layer; the Beidou network device uses the application layer message as the first MDCP SDU at the MDCP layer, and divides the first MDCP SDU into M MDCP PDUs.

[0034] In a possible implementation, a Beidou network device generates an application layer message at the application layer, specifically including: the Beidou network device obtains 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.

[0035] In a possible implementation, the Beidou network device sends the first MDCP PDU, specifically including: the Beidou network device transmits the first MDCP PDU to the satellite link control SLC layer as the first satellite link control layer service data unit SLC SDU of the SLC layer; the Beidou network device divides the first SLC SDU into N satellite link control layer protocol data units SLC PDU at the SLC layer, where N is a positive integer; wherein the N SLC PDUs include the first SLC PDU, and the frame header information of the first SLC PDU includes a first user ID field and a first frame type field, the first user ID field is used to indicate a terminal receiving a first user frame, and the first frame type field is used to indicate a frame type of the first user frame; the Beidou network device sends the first SLC PDU.

[0036] In a possible implementation, a Beidou network device sends a first physical frame and a second physical frame, including: the Beidou network device adds first check bit information at the end of the first physical frame at the PHY layer, encodes the first physical frame and the first check bit information to obtain first coded data, adds second check bit information at the end of the second physical frame, and encodes the second physical frame and the second check bit information to obtain second 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, and modulates the second coded data and the second reserved field of the second coded data to obtain second modulated data; the Beidou network device spreads the first modulated data at the PHY layer to obtain first spread spectrum modulated data, and spreads the second modulated data to obtain second 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, as well as the second spread spectrum modulated data and the second pilot information of the second spread spectrum modulated data at the PHY layer.

[0037] In a possible implementation manner, the method further includes: the Beidou network device determines the data length of the first MDCP PDU according to the data length of the first MDCP SDU and the data length of the first physical frame.

[0038] In this way, the Beidou network device can know how to split the MDCP SDU into multiple MDCP PDUs.

[0039] In a fourth aspect, a data transmission control method in a Beidou communication system is provided, which may include: a terminal receives M data convergence layer service protocol data units MDCP PDUs sent by a Beidou network device, where M is a positive integer; wherein the M MDCP PDUs include a first MDCP PDU, and the header information of the first MDCP PDU includes a successor indication field, which is used to indicate the order of the first MDCP PDU in the M MDCP PDUs; the terminal splices the M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer.

[0040] In this way, data can be reliably transmitted between Beidou network devices and terminals under the constraints of the Beidou communication system and rate limitations.

[0041] Among them, in one possible implementation, M is greater than 1, the successor indication field of the first MDCP PDU is a first value, and the first value is used to indicate that the first MDCP PDU is the first MDCP PDU among M MDCP PDUs; M is greater than 1, the successor indication field of the first MDCP PDU is a second value, and the second value is used to indicate that the first MDCP PDU is the middle MDCP PDU among the M MDCP PDUs; M is greater than 1, the successor indication field of the first MDCP PDU is a third value, and the third value is used to indicate that the first MDCP PDU is the last MDCP PDU among the M MDCP PDUs.

[0042] In a possible implementation manner, M is 1, and the successor indication field of the first MDCP PDU is a fourth value, and the fourth value is used to indicate that the first MDCP PDU is a separate MDCP PDU.

[0043] In this way, the terminal can accurately splice multiple MDCP PDUs into an MDCP SDU according to the order of the MDCP PDU in multiple MDCP PDUs indicated by the successor indication field in the MDCP PDU.

[0044] In a possible implementation, the terminal splices M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at a message data convergence MDCP layer, including: when a second MDCP PDU received by the terminal subsequently indicates that the second MDCP PDU is the last one of the M MDCP PDUs, the terminal splices the M MDCP PDUs into a first MDCP SDU at the MDCP layer, and reports the first MDCP SDU from the MDCP layer to the application layer as an application layer message.

[0045] 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 original data into compressed data, and the encryption indication field is used to indicate the encryption algorithm used by the terminal when encrypting compressed data into encrypted data; the method also includes: the 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 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.

[0046] In a possible implementation, the method may also include: the Beidou network device splices N SLC PDUs into a first SLC SDU at the SLC layer, and reports the first SLC SDU as a first MDCP PDU from the SLC layer of the Beidou network device to the MDCP layer of the Beidou network device; wherein the N SLC PDUs include a first SLC PDU, and the frame header information of the first SLC PDU includes a first user ID field and a first frame type field, the first user ID field is used to indicate a terminal receiving a first user frame, and the first frame type field is used to indicate a frame type of the first user frame.

[0047] In a possible implementation, before the terminal splices N SLC PDUs into a first SLC SDU at the SLC layer and reports the first SLC SDU as a first MDCP PDU from the SLC layer of the Beidou network device to the MDCP layer of the Beidou network device, the method may also include: the terminal obtains the first spread spectrum modulation data sent by the terminal at the PHY layer; the terminal despreads the first spread spectrum modulation data at the PHY layer to obtain the first modulation data and the first modulation synchronization header; the terminal demodulates the first modulation data and the first modulation synchronization header at the PHY layer to obtain the first pilot data and the first synchronization header; the terminal 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 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 in the first coded block with the same ID field as the terminal ID as the first SLC PDU in the first SLC SDU in the SLC layer of the terminal from the PHY layer to the SLC layer of the terminal.

[0048] In a possible implementation, the terminal splices M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at a message data convergence MDCP layer, including: after the terminal removes a successor indication field of each MDCP PDU in the M MDCP PDUs at the MDCP layer, splices the M MDCP PDUs into a first MDCP SDU in an order indicated by a successor indication of each MDCP PDU in the M MDCP PDUs.

[0049] In the fifth aspect, a Beidou communication system is provided, which may include Beidou network equipment and terminals; wherein the terminal can be used to execute the method in any possible implementation of the first aspect and the fourth aspect above; the Beidou network equipment can be used to execute the method in any possible implementation of the second aspect and the third aspect above.

[0050] In a sixth 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, and the one or more memories are used to store computer program codes, and the computer program codes include computer instructions. When the one or more processors execute the computer instructions, the communication device executes the method in any possible implementation of the first aspect and the fourth aspect.

[0051] The communication device may be a terminal or other equipment in other product forms.

[0052] In a seventh 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, and the one or more memories are used to store computer program codes, and the computer program codes include computer instructions, and when the one or more processors execute the computer instructions, the communication device executes the method in any possible implementation of the second aspect and the third aspect.

[0053] Among them, the communication device can be a Beidou network device, or any network element or a combination of multiple network elements in the Beidou network device.

[0054] In an eighth aspect, the present application provides a computer storage medium, comprising computer instructions, which, when executed on a computer, enable the computer to execute a method in any possible implementation of the second and third aspects above.

[0055] In a ninth aspect, the present application provides a computer storage medium comprising computer instructions, which, when executed on a computer, enable the computer to execute a method in any possible implementation of the first and fourth aspects above.

[0056] In a tenth aspect, the present application provides a computer program product, which, when executed on a computer, enables the computer to execute a method in any possible implementation of the second and third aspects above.

[0057] In an eleventh aspect, the present application provides a computer program product, which, when executed on a computer, enables the computer to execute a method in any possible implementation of the first and fourth aspects above.

[0058] In the twelfth 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 method of the above-mentioned first aspect and fourth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 1 is a schematic diagram of the architecture of a Beidou communication system 10 provided in an embodiment of the present application;

[0060] Figure 2 It is a schematic diagram of the transmission process of data inbound in a Beidou communication system provided in an embodiment of the present application;

[0061] Figure 3 1 is a schematic diagram of a protocol encapsulation architecture of inbound data of a Beidou communication system 10 provided in an embodiment of the present application;

[0062] Figure 4 It is a schematic diagram of a protocol parsing architecture of inbound data of a Beidou communication system 10 provided in an embodiment of the present application;

[0063] Figure 5 This is a schematic diagram of a scenario in which multiple MDCP PDUs are successfully transmitted according to an embodiment of the present application;

[0064] Figure 6 This is a schematic diagram of a scenario in which a single MDCP PDU is successfully transmitted provided by an embodiment of the present application;

[0065] Figure 7 It is a schematic diagram of a scenario in which multiple MDCP PDU transmissions fail according to an embodiment of the present application;

[0066] Figure 8 It is a schematic diagram of a scenario in which multiple MDCP PDU transmissions fail according to an embodiment of the present application;

[0067] Fig. 9 This is a schematic diagram of a scenario in which multiple MDCP PDUs are successfully transmitted according to an embodiment of the present application;

[0068] Fig.10 It is a schematic diagram of the protocol processing flow of data at the MDCP layer and the SLC layer of the Beidou communication system 10 provided in an embodiment of the present application;

[0069] Fig.11A 1 is a schematic diagram of a protocol encapsulation architecture of outbound data of a Beidou communication system 10 provided in an embodiment of the present application;

[0070] Fig. 11B It is a schematic diagram of a protocol parsing architecture of outbound data of a Beidou communication system 10 provided in an embodiment of the present application;

[0071] Fig. 11C A flowchart of a data transmission control method in a Beidou communication system provided in an embodiment of the present application;

[0072] Fig.11D A flowchart of a data transmission control method in a Beidou communication system provided in an embodiment of the present application;

[0073] Fig.12 is a schematic diagram of the structure of the terminal 100 provided in an embodiment of the present application;

[0074] Fig.13 A schematic diagram of the structure of a communication device provided in an embodiment of the present application;

[0075] Fig.14 A schematic diagram of the structure of another communication device provided in an embodiment of the present application;

[0076] Fig.15 A schematic diagram of the structure of another communication device provided in an embodiment of the present application;

[0077] Fig.16 A schematic diagram of the structure of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0078] The terms used in the following embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to be used as limitations to the present application. As used in the specification and appended claims of the present application, the singular expressions "one", "a kind of", "said", "above", "the" and "this" are intended to also include plural expressions, unless there is a clear indication to the contrary in the context. It should also be understood that the term "and / or" used in the present application refers to and includes any or all possible combinations of one or more listed items.

[0079] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features, and in the description of the embodiments of the present application, unless otherwise specified, "plurality" means two or more.

[0080] The following introduces a Beidou communication system 10 provided in an embodiment of the present application.

[0081] Figure 1 A schematic diagram of the architecture of a Beidou communication system 10 provided in an embodiment of the present application is shown.

[0082] 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 also include a national emergency rescue platform 26 and a national emergency rescue center 27.

[0083] Among them, the terminal 100 can send short message information to the Beidou short message satellite 21, and the Beidou short message satellite 21 only relays and directly forwards the short message information sent by the terminal 100 to the Beidou network device 200 on the ground. The Beidou network device 200 can parse the short message information forwarded by the satellite according to the Beidou communication protocol, and forward the message content of the general message type parsed from the short message information to the short message center (SMSC) 25. The short message center 25 can forward the message content to the terminal 300 through the traditional cellular communication network. The Beidou network device 200 can also send the emergency rescue type message sent by the terminal 100 to the national emergency rescue center 27 through the national emergency rescue platform 26.

[0084] The terminal 300 can also send the short message to the short message center 25 through the 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 through the Beidou short message satellite 21.

[0085] 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 having a sending function and one or more devices having a receiving function, respectively, or may include one or more devices having 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 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).

[0086] Among them, since the Beidou communication system 10 communicates via satellite links, its main characteristics are: extended time (about 270ms one-way) and large link loss. The services currently supported by the Beidou communication system 10 are mainly burst short message services, and do not support link status management, mobility management, and broadcast control information.

[0087] The terminal 100 can actively send data to the Beidou network device 200 through the Beidou short message satellite 21. However, due to the lack of air interface signaling, the central station on the ground cannot actively page the user. Due to the long propagation distance of satellite communication, the Beidou communication system 10 has high requirements for the transmission power of the terminal 100. Limited by the limitations of the radio frequency devices on the current terminal 100, the terminal 100 cannot continuously send signals to the Beidou short message satellite 21 for a long time. In order to minimize damage to the radio frequency devices on the terminal 100, the radio frequency devices of the terminal 100 must stop working for a period of time after the sending state continues to work for a period of time before continuing to switch to the sending state to continue working. Among them, the duration of the sending state on the terminal 100 is determined by the underlying hardware capabilities of the terminal 100. In the above-mentioned Beidou communication system 10, in order to ensure that the data received by the terminal 100 and the data sent do not interfere with each other, the terminal 100 does not support sending data and receiving data at the same time. The terminal 100 needs to wait for receiving the data sent by the Beidou network device 200 after sending the data.

[0088] Among them, the working mode of the Beidou network device 200 can be a duplex mode, data can be sent and received at the same time, and the Beidou network device 200 can send and receive data for a long time.

[0089] The usage habits of ordinary consumers may send more data at a time. When the data is large, the terminal needs to send multiple frames of data, which will take a long time to send. In order to avoid invalid transmission, a separate layer of protocol is needed to manage multiple frames sent by users. Therefore, the message convergence protocol (MDCP) is defined. The MDCP layer can receive the application layer data passed down by the application layer and send the processed data packets to the lower satellite link control protocol (SLC).

[0090] Based on the MDCP layer, an embodiment of the present application provides a data transmission control method in a Beidou communication system, and the terminal 100 can use the application layer message as an MDCP SDU of the MDCP layer. The terminal 100 can add padding data (padding) to the specified length at the end of an MDCP SDU of the MDCP layer, and add a redundant length indication field at the end of the padding data field or the head of the MDCP SDU. The redundant length indication field can be used to indicate the length of the padding data. The terminal 100 can split the MDCP SDU after filling the redundant data and adding the redundant length indication field into one or more fixed-length MDCP segmented data (M_segement), and add a subsequent indication field to the head of each MDCP segmented data to obtain an MDCP PDU, that is, the MDCP PDU includes an M_segement and a subsequent indication field. Among them, the subsequent indication field can be used to indicate that the current MDCP PDU is the starting frame, the middle frame, or the last frame in the continuously sent frames; or a frame sent separately. The terminal 100 can send one or more MDCP PDUs to the Beidou network device 200. The Beidou network device 200 may combine multiple MDCP PDUs into one MDCP SDU according to the subsequent indication field in the MDCP PDU.

[0091] In this way, under the constraints of the Beidou communication system and rate limitation, the terminal 100 can also send data to the Beidou network device 200.

[0092] In the embodiment of the present application, the scenario in which the terminal 100 sends data to the Beidou network device 200 is defined as inbound, and the scenario in which the Beidou network device 200 sends data to the terminal 100 is defined as outbound.

[0093] Figure 2 A schematic diagram of the data inbound transmission process in a Beidou communication system provided in an embodiment of the present application is shown.

[0094] like Figure 2As shown, data inbound may refer to the terminal 100 sending data to the Beidou network device 200. For example, the terminal 100 may send a data frame to the Beidou ground transceiver station 22. The Beidou ground transceiver station 22 may send the data frame to the Beidou central station 23. The Beidou central station 23 may aggregate the data frame into a data message and report it to the Beidou short message fusion communication platform 24. After receiving the data frame sent by the terminal 100, the Beidou central station 23 may return an acknowledgement character (ACK) of the SLC layer to the terminal 100. The ACK may be used to indicate whether the Beidou network device 200 has successfully received the data frame sent by the terminal 100.

[0095] The following introduces a protocol encapsulation architecture for inbound data of a Beidou communication system 10 provided in an embodiment of the present application.

[0096] Figure 3 A schematic diagram of a protocol encapsulation architecture for inbound data of a Beidou communication system 10 provided in an embodiment of the present application is shown.

[0097] like Figure 3 As shown, the Beidou message transmission protocol layer on the terminal 100 can be divided into an application layer (application layer protocol), a message data convergence protocol (MDCP), a satellite link layer (satellite link control protocol, SLC) and a physical layer (physical layer protocol, PHY).

[0098] When the terminal 100 sends data to the Beidou network device 200, the workflow of the Beidou message transmission protocol on the terminal 100 may be as follows:

[0099] At the APP layer, the terminal 100 can compress the original data into compressed data through a compression algorithm, and add a compression indication field in front of the compressed data, wherein the compression indication field can be used to indicate the compression algorithm type of the compressed data. Afterwards, the terminal 100 can encrypt the compressed data to obtain encrypted data, and add an encryption algorithm field to the header of the encrypted data, wherein the encryption algorithm field is used to indicate the encryption algorithm type of the encrypted data. The terminal 100 can encapsulate the encrypted data, the compression indication field, and the encryption indication field into an application layer message and send it to the MDCP layer. The application layer message includes a message header and message data. The message header includes a compression indication field and an encryption indication field, etc. The message data includes the above-mentioned encrypted data.

[0100] Optionally, the terminal 100 may also encrypt the compression indication field and the compressed data together to obtain encrypted data.

[0101] At the MDCP layer, the terminal 100 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 terminal 100 can add padding data (padding) to the tail of the MDCP SDU to a specified length, and add a redundant length indication field to the head of the MDCP SDU. The redundant length indication field can be used to indicate the length of the padding data. The terminal 100 can split the padding data and the MDCP SDU after adding the redundant length indication field into one or more fixed-length MDCP segmented data (M_segement), and add a subsequent indication field to the head of each MDCP segmented data to obtain an MDCP PDU, that is, the MDCP PDU includes an M_segement and a subsequent indication field. Among them, the subsequent indication field can be used to indicate that the current MDCP PDU is the starting MDCP PDU or the middle MDCP PDU or the last MDCP PDU of multiple MDCP PDUs sent continuously; or it is an MDCP PDU sent separately.

[0102] At the SLC layer, the terminal 100 can obtain the MDCP PDU sent by the MDCP layer as the SLC SDU through the inter-layer interface. At the SLC layer, the terminal 100 can segment the SLC SDU into one or more (up to 4) fixed-length SLC segment data (S_segement), and add frame header information to each S_segement header to obtain the SLC PDU. The frame header information includes the service data unit alternated indicator (SAI) field, the total number of frames field, and the frame sequence number field.

[0103] The SAI field may be used to indicate whether the SLC PDU belongs to an SLC SDU that has not been sent.

[0104] The total number of frames field may be used to indicate the total number of SLC PDUs included in the SLC SDU to which the SLC PDU belongs.

[0105] The frame sequence number field can be used to indicate the sequence number of the SLC PDU in the SLC SDU to which it belongs.

[0106] At the PHY layer, the terminal 100 can obtain the SLC PDU issued by the SLC layer through the inter-layer interface as the code block of the PHY layer, and add a synchronization header to the head of the code block and a check bit field to the tail of the code block. Among them, in the above-mentioned Beidou communication system 10, a cyclic redundancy check (CRC) can be used to check the code block, so the check bit field can include a CRC code. The terminal 100 can encode the codeblock and the check bit field (for example, polar encoding) to obtain coded data, and then insert a pilot into the coded data to obtain pilot coded data (pilot+data). Then, the terminal 100 modulates the synchronization header and the pilot coded data in sequence through the underlying hardware to obtain modulated data (modulateddata). The terminal 100 can spread the modulated data to obtain spread spectrum modulated data (spread+modulateddata). The terminal 100 can send the spread spectrum modulated data to the Beidou short message satellite 21, and forward it to the Beidou network device 200 via the Beidou short message satellite 21 relay.

[0107] The following introduces a protocol parsing architecture for inbound data of a Beidou communication system 10 provided in an embodiment of the present application.

[0108] Figure 4 A schematic diagram of a protocol parsing architecture for inbound data of a Beidou communication system 10 provided in an embodiment of the present application is shown.

[0109] like Figure 4 As shown, the Beidou short message transmission protocol layer of the Beidou network device 200 can be divided into 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.

[0110] When the Beidou network device 200 receives the data sent by the terminal 100, the working process of the Beidou short message transmission protocol layer of the Beidou network device 200 may be as follows:

[0111] At the PHY layer, the Beidou network device 200 can obtain the pilot coded data sent by the terminal 100 after modulation and spread spectrum. The Beidou network device 200 can despread the received spread spectrum modulated data (spread+modulateddata) to obtain modulated data (modulateddata). Then, the Beidou network device 200 can demodulate the modulated data to obtain pilot coded data (pilot+data). Next, the Beidou network device 200 removes the pilot information in the pilot coded data to obtain coded data (codedata). Then, the Beidou network device 200 can decode the coded data and verify the integrity of the coded block (codeblock) through the check data in the check bit field. If complete, the Beidou network device 200 can extract the coded block (codeblock) and present it to the SLC layer through the inter-layer interface as the SLC PDU of the SLC layer.

[0112] At the SLC layer, the Beidou network device 200 can splice the SLC PDUs belonging to the same SLC SDU into one SLC SDU based on the frame header information of the SLC PDU. The Beidou network device 200 can present the SLC SDU to the MDCP layer through the inter-layer interface as the MDCP PDU of the MDCP layer.

[0113] At the MDCP layer, the Beidou network device 200 can concatenate all MDCP PDUs belonging to the same MDCP SDU into one MDCP SDU. The Beidou network device 200 can present the MDCP SDU to the APP layer through the inter-layer interface as an application layer message received by the APP layer.

[0114] At the APP layer, the Beidou network device 200 can decrypt and decompress the application layer message based on the message header of the application layer message to obtain the original data.

[0115] In the embodiments of the present application, the above-mentioned protocol processing process is only an example for illustration, and the present application does not limit the specific operations of the protocol processing.

[0116] Next, the fields involved in the MDCP SDU and MDCP PDU in the MDCP layer are introduced in detail.

[0117] 1. Redundant length indication field in MDCP SDU

[0118] The redundant length indication field is used to indicate the length of the padding in the MDCP SDU. In a possible implementation, the length of the redundant length indication field is 8 bits. It is understandable that the embodiment of the present application does not limit the length of the redundant length indication field.

[0119] 2. Subsequent indication field in MDCP PDU

[0120] The data length of the subsequent indication field may be 2 bits. In a possible implementation, the value and corresponding meaning of the subsequent indication field may be as shown in Table 1 below.

[0121] Table 1

[0122] Subsequent instructions illustrate 00 A single MDCP PDU 01 The first PDU among multiple MDCP PDUs 11 The middle PDU among multiple MDCP PDUs 10 The last PDU among multiple MDCP PDUs

[0123] As shown in Table 1, when the successor indication field is "00", it indicates that the MDCP PDU is a single MDCP PDU; when the successor indication field is "01", it indicates that the MDCP PDU is the first PDU among multiple MDCP PDUs; when the successor indication field is "11", it indicates that the MDCP PDU is the middle PDU among multiple MDCP PDUs; when the successor indication field is "10", it indicates that the MDCP PDU is the last PDU among multiple MDCP PDUs.

[0124] It is understandable that the values ​​and corresponding meanings of the successor indication field shown in Table 1 are only examples. The embodiment of the present application does not limit the length of the successor indication field, the specific bit value of the successor indication field, and the meaning corresponding to the bit value.

[0125] The following describes the design of the successor indication field based on Table 1, and introduces the transmission scenarios of the MDCP PDU when there is no 00 field in the successor indication field of the MDCP PDU and when there is a 00 field in the successor indication field of the MDCP PDU.

[0126] 1. Transmission scenario of MDCP PDU when there is no 00 field in the successor indication field.

[0127] When there is no 00 field in the successor indication field, that is, when the length of the successor indication field is 2 bits, the value of the successor indication field does not include "00" and the corresponding meaning. The value of the successor indication field includes: "01", "10", "11".

[0128] When the MDCP PDU is the first MDCP PDU among multiple MDCP PDUs, the successor indication field of the MDCP PDU may be "01". When the MDCP PDU is the middle MDCP PDU among multiple MDCP PDUs, the successor indication field of the MDCP PDU may be "11". When the MDCP PDU is a single MDCP PDU or the last MDCP PDU among multiple MDCP PDUs, the successor indication field of the MDCP PDU may be "10".

[0129] Scenario 1: Multiple MDCP PDUs are successfully transmitted

[0130] Figure 5 The example shows a scenario in which multiple MDCP PDUs are successfully transmitted when there is no 00 field in the subsequent indication field.

[0131] like Figure 5 As shown, the terminal 100 can send 4 MDCP PDUs to the Beidou network device 200. Among the 4 MDCP PDUs, the MDCP PDU with the successor indication field of "01" is the first MDCP PDU, the MDCP PDU with the successor indication field of "11" is the middle MDCP PDU, and the MDCP PDU with the successor indication field of "10" is the last PDU packet. In the normal transmission process of the 4 MDCP PDUs, the Beidou network device 200 can successfully receive the 4 MDCP PDUs.

[0132] It is understandable that after the terminal 100 sends an MDCP PDU to the Beidou network device 200, the terminal 100 sends a new MDCP PDU to the Beidou network device 200 only after receiving the ACK replied by the Beidou network device 200 to the SLC SDU corresponding to the MDCP PDU.

[0133] Scenario 2: Single MDCP PDU transmission is successful

[0134] Figure 6 The example shows a scenario in which a single MDCP PDU is successfully transmitted when there is no 00 field in the subsequent indication field.

[0135] like Figure 6 As shown, the terminal 100 can send a single MDCP PDU to the Beidou network device 200. The successor indication field of the MDCP PDU is "10". The Beidou network device 200 can successfully receive the single MDCP PDU.

[0136] Scenario 3: The last MDCP PDU among multiple MDCP PDUs is not received and the waiting timeout occurs

[0137] Figure 7 The example shows a scenario in which multiple MDCP PDU transmissions fail when there is no 00 field in the subsequent indication field.

[0138] like Figure 7 As shown, the terminal 100 can send 4 MDCP PDUs to the Beidou network device 200. Among the 4 MDCP PDUs, the MDCP PDU with the successor indication field of "01" is the first MDCP PDU, the MDCP PDU with the successor indication field of "11" is the middle MDCP PDU, and the MDCP PDU with the successor indication field of "10" is the last PDU packet. The Beidou network device 200 did not receive the last MDCP PDU of the 4 MDCP PDUs sent by the terminal 100. The Beidou network device 200 waited for a timeout, the terminal 100 transmission failed, and this transmission ended normally.

[0139] In the case where the Beidou network device has timed out waiting at the MDCP layer, that is, the Beidou network device has timed out waiting to receive the SLC SDU at the SLC layer. For example, an SLC SDU includes N SLC PDUs, and the maximum time for the terminal to receive each SLC PDU is the first duration. If the Beidou network device has received an MDCP PDU at the MDCP layer and has not received the next MDCP PDU after the second duration, it can be called that the Beidou network device has timed out waiting at the MDCP layer. Among them, the second duration can be N first durations.

[0140] Scenario 4: The last MDCP PDU among multiple MDCP PDUs is not received and the waiting time does not expire

[0141] Figure 8 The example shows a scenario in which multiple MDCP PDU transmissions fail when there is no 00 field in the subsequent indication field.

[0142] like Figure 8As shown, the terminal 100 can send 4 MDCP PDUs to the Beidou network device 200. Among the 4 MDCP PDUs, the MDCP PDU with a successor indication field of "01" is the first MDCP PDU, the MDCP PDU with a successor indication field of "11" is the middle MDCP PDU, and the MDCP PDU with a successor indication field of "10" is the last PDU packet. The Beidou network device 200 did not receive the last MDCP PDU of the 4 MDCP PDUs sent by the terminal 100. The Beidou network device 200 waited for no timeout, and the terminal 100 initiated a new service, that is, sent a new MDCP PDU, which is a separate MDCP PDU, and the successor indication field of the separate MDCP PDU is "10". For example, when the terminal sends the MDCP PDU, an exception occurs and the terminal crashes, and then the user initiates a service on the terminal again. At this time, the Beidou network device 200 may regard the single MDCP PDU as the last MDCP PDU of the four MDCP PDUs previously sent by the terminal 100. Then, the Beidou network device 200 combines the single MDCP PDU and three MDCP PDUs of the four MDCP PDUs received last time into one MDCP SDU. In this way, the Beidou network device 200 incorrectly reassembles the MDCP SDU packet.

[0143] 2. Transmission scenario of MDCP PDU when there is a 00 field in the successor indication field.

[0144] The value of the successor indication field includes: "00", "01", "10", "11". The corresponding meaning of the value of the successor indication field can refer to the description in the above Table 1.

[0145] Scenario 5: The last PDU in multiple MDCP PDUs is not received and the waiting time does not expire

[0146] Fig. 9 The example shows a scenario in which multiple MDCP PDU transmissions fail when there is no 00 field in the subsequent indication field.

[0147] like Fig. 9As shown, the terminal 100 can send 4 MDCP PDUs to the Beidou network device 200. Among the 4 MDCP PDUs, the MDCP PDU with a successor indication field of "01" is the first MDCP PDU, the MDCP PDU with a successor indication field of "11" is the middle MDCP PDU, and the MDCP PDU with a successor indication field of "10" is the last PDU packet. The Beidou network device 200 did not receive the last MDCP PDU of the 4 MDCP PDUs sent by the terminal 100. The Beidou network device 200 waited for no timeout, and the terminal 100 sent another separate MDCP PDU, and the successor indication field of the separate MDCP PDU was "00". The Beidou network device 200 can determine that the MDCP PDU is a separate MDCP PDU based on the successor indication field "00" of the MDCP PDU. In this way, the Beidou network device 200 will not reassemble the separate MDCP PDU with the MDCP PDU received by the Beidou network device 200 last time into an MDCP SDU. That is, the Beidou network device 200 will not have the problem of misassembling packets.

[0148] The following specifically introduces the protocol processing flow of the Beidou communication system 10 for data at the MDCP layer and the SLC layer.

[0149] Fig.10 A schematic diagram of the protocol processing flow of data at the MDCP layer and the SLC layer of the Beidou communication system 10 provided in an embodiment of the present application is shown.

[0150] 1. The protocol encapsulation process of the terminal 100 for sending data at the MDCP layer

[0151] like Fig.10 As shown, at the MDCP layer, the terminal 100 can split the MDCP SDU after the (padding) data and the redundant length indication field into one or more fixed-length MDCP segmented data (M_segement), and add a subsequent indication field to the header of each MDCP segmented data to obtain an MDCP PDU, that is, the MDCP PDU includes an M_segement and a subsequent indication field. The terminal 100 can store the split MDCP PDU in the MDCP layer send buffer (MDCP Tx buffer) in a first-in-first-out order. Among them, the data length of the subsequent indication field can occupy 2 bits (bit). The value meaning of the subsequent indication field can be as shown in Table 1 above.

[0152] Exemplarily, the terminal 100 may split the MDCP SDU after padding data and adding the redundant length indication field into three MDCP PDUs, wherein, in order from high bits to low bits, the three MDCP PDUs are MDCP PDU0, MDCP PDU1 and MDCP PDU2. Among them, since MDCP PDU0 is the starting MDCP PDU in the current MDCP SDU, the terminal 100 may set the value of the successor indication field in MDCP PDU0 to "01". Since MDCP PDU1 is the middle MDCP PDU in the current MDCP SDU, the terminal 100 may set the value of the successor indication field in MDCP PDU1 to "11". MDCP PDU2 is the last MDCP PDU in the current MDCP SDU, and the terminal 100 may set the value of the successor indication field in MDCP PDU2 to "10".

[0153] As another example, the terminal 100 may split the MDCP SDU after padding data and adding the redundant length indication field into two MDCP PDUs, wherein, in order from high bit to low bit, the two MDCP PDUs are MDCP PDU0 and MDCP PDU1. Since MDCP PDU0 is the starting MDCP PDU in the current MDCP SDU, the terminal 100 may set the value of the subsequent indication field in MDCP PDU0 to "01". Since MDCP PDU1 is the last MDCP PDU in the current MDCP SDU, the terminal 100 may set the value of the subsequent indication field in MDCP PDU1 to "10".

[0154] As another example, the terminal 100 may treat the MDCP SDU after the padding data and the redundant length indication field are added as 1 MDCP PDU0. Since MDCP PDU0 is the only MDCP PDU in the current MDCP SDU, the terminal 100 may set the value of the subsequent indication field in MDCP PDU0 to "00".

[0155] In the embodiment of the present application, due to the limited capabilities of the terminal bottom layer, the data length of a physical frame is limited, and the data length that can be sent by an SLC layer is limited by the physical frame length. Therefore, the SLC layer needs to split the SLC SDU into multiple SLC PDUs. The data length in the SLC PDU will limit the data length sent by the MDCP layer. Therefore, the MDCP layer also needs to split an MDCP SDU into one or more MDCP PDUs.

[0156] 2. The terminal 100 performs protocol encapsulation of the sent data at the SLC layer.

[0157] At the SLC layer, the terminal 100 can control the SLC PDU sending strategy of the SLC layer, including the initial transmission and retransmission of the SLC PDU, through the SLC layer sending state controller based on the receiving feedback (e.g., ACK) sent by the Beidou network device 200. The terminal 100 can obtain the MDCP PDU sent by the MDCP layer as the SLC SDU through the inter-layer interface. Among them, when the terminal 100 sends the previous SLC SDU to the Beidou network device 200 and confirms that the Beidou network device 200 has received it successfully, it will obtain the next MDCP PDU from the MDCP layer as the next SLC SDU and send it to the Beidou network device 200.

[0158] Optionally, in a possible implementation manner, the terminal 100 divides the MDCP SDU into multiple MDCP PDUs at the MDCP layer, and the terminal 100 may transmit the multiple MDCP PDUs to the SLC layer of the terminal 100 together.

[0159] Exemplarily, the terminal 100 may split the MDCP SDU after padding data and adding the redundant length indication field into three MDCP PDUs. Among them, in order from high bit to low bit, the three MDCP PDUs are MDCP PDU0, MDCP PDU1 and MDCP PDU2. At the SLC layer, the terminal 100 first obtains the MDCP PDU0 sent by the MDCP layer through the inter-layer interface, and the terminal 100 may send MDCP PDU0 as the first SLC SDU of the SLC layer in this message transmission process to the Beidou network device 200. After the terminal 100 determines that the data of the first SLC SDU has been sent to the Beidou network device 200, the terminal 100 may obtain MDCP PDU1 from the MDCP layer, and send MDCP PDU1 as the second SLC SDU in this message transmission process to the Beidou network device 200. After the terminal 100 determines that the Beidou network device 200 has sent the data of the second SLC SDU to the Beidou network device 200, the terminal 100 can obtain MDCP PDU2 from the MDCP layer, and send MDCP PDU2 to the Beidou network device 200 as the last SLC SDU of this message transmission process.

[0160] The above examples are only used to explain the present application and should not be construed as limiting.

[0161] At the SLC layer, the terminal 100 can segment the SLC SDU into one or more SLC segment data (S_segement) of fixed length, and add frame header information to each S_segement header to obtain the SLC PDU. The frame header information includes the SAI field, the total number of frames field, and the frame sequence number field. Among them:

[0162] (1) The SAI field can occupy 1 bit. The value of the SAI field can be "0" or "1". The terminal 100 can determine whether the SLC PDU to be sent currently belongs to an SLC SDU that has not been sent. If so, the terminal 100 can set the value of the SAI field in the SLC PDU to be different from the value of the SAI field of the SLC PDU in the previous SLC SDU session (including the SLC SDU initial transmission session or the SLC SDU retransmission session); if not, the terminal 100 can set the value of the SAI field in the SLC PDU to be the same as the value of the SAI field of the SLC PDU in the previous SLC SDU session. When the value of the SAI field in the SLC PDU is the same as the value of the SAI field of the SLC PDU in the previous SLC SDU session, it indicates that the SLC PDU is retransmitted data.

[0163] It is understandable that the SAI field has a preset initial value, and the SAI field of the first SLC SDU sent by the terminal 100 to the Beidou network device 200 is the preset initial value. If the SAI field of the first SLC SDU received by the Beidou network device 200 is not the preset initial value, the Beidou network device 200 can directly discard the SLC SDU. The preset initial value of the SAI field in the SLC SDU can be 0 or other values, and this application does not limit the preset initial value of the SAI field.

[0164] Exemplarily, the terminal 100 needs to transmit 3 SLC SDUs during the entire application layer message transmission process. Each SLC SDU may include 4 SLC PDUs. Among them, the values ​​of the SAI fields of the 4 SLC PDUs in the first SLC SDU may all be "0", and the values ​​of the SAI fields of the 4 SLC PDUs in the second SLC SDU may all be "1". The values ​​of the SAI fields of the 4 SLC PDUs in the third SLC SDU may all be "0".

[0165] The above examples are only used to explain the present application and should not be construed as limiting.

[0166] (2) The total number of frames field may be used to indicate the total number of SLC PDUs included in the SLC SDU to which the SLC PDU belongs. When an SLC SDU in the Beidou communication system 10 can be divided into at most 4 SLC segment data (S_segement) of fixed length, the total number of frames field may occupy 2 bits.

[0167] Exemplarily, when the SLC SDU includes only one SLC PDU, the value of the total number of frames field of the only SLC PDU in the SLC SDU can be "00". When the SLC SDU includes two SLC PDUs, the values ​​of the total number of frames fields of the two SLC PDUs in the SLC SDU can both be "01". When the SLC SDU includes three SLC PDUs, the values ​​of the total number of frames fields of the three SLC PDUs in the SLC SDU can both be "10". When the SLC SDU includes four SLC PDUs, the values ​​of the total number of frames fields of the four SLC PDUs in the SLC SDU can all be "11".

[0168] The above examples are only used to explain the present application and should not be construed as limiting.

[0169] (3) A frame sequence number field, which can be used to indicate the sequence number of the SLC PDU in the SLC SDU to which it belongs. When a SLC SDU in the Beidou communication system 10 can be divided into at most 4 SLC segment data (S_segement) of fixed length, the frame sequence number field can occupy 2 bits.

[0170] Exemplarily, when the SLC SDU includes only one SLC PDU, the value of the frame sequence number field of the only SLC PDU in the SLC SDU may be "00". When the SLC SDU includes two SLC PDUs, the value of the frame sequence number field in the first SLC PDU in the SLC SDU may be "00", and the value of the frame sequence number field in the second SLC PDU in the SLC SDU may be "01". When the SLC SDU includes three SLC PDUs, the value of the frame sequence number field in the first SLC PDU in the SLC SDU may be "00", the value of the frame sequence number field in the second SLC PDU in the SLC SDU may be "01", and the value of the frame sequence number field in the third SLC PDU in the SLC SDU may be "10". When the SLC SDU includes 4 SLC PDUs, the value of the frame sequence number field in the first SLC PDU in the SLC SDU can be "00", the value of the frame sequence number field in the second SLC PDU in the SLC SDU can be "01", the value of the frame sequence number field in the third SLC PDU in the SLC SDU can be "10", and the value of the frame sequence number field in the fourth SLC PDU in the SLC SDU can be "11".

[0171] The above examples are only used to explain the present application and should not be construed as limiting.

[0172] 3. The Beidou network device 200 performs protocol parsing of received data at the SLC layer.

[0173] At the SLC layer, after the Beidou network device 200 receives the SLC PDU of the terminal 100, it can determine whether all the SLC PDUs in an SLC SDU have been received based on the frame header information of the SLC PDU. If so, the Beidou network device 200 can splice the received one or more SLC PDUs into an SLC SDU in order from small to large according to the value of the frame sequence number field. If all the SLC PDUs in an SLC SDU have not been received, the Beidou network device 200 can send feedback information (for example, ACK) to notify the terminal 100 to retransmit the unreceived SLC PDU after the SLC layer receiving window ends. After splicing the SLC SDU, the Beidou network device 200 can report the SLC SDU to the MDCP layer through the inter-layer interface as an MDCP PDU.

[0174] Among them, the Beidou network device 200 can control the sending strategy of the feedback information (e.g., ACK) of the SLC layer and the splicing of the SLC PDU through the SLC layer receiving state controller at the SLC layer based on the SAI field in the SLC PDU. The duration of the SLC layer receiving state controller is the maximum retransmission time of the SLC PDU on the terminal 100.

[0175] Exemplarily, the SAI value of the first SLC PDU in the first SLC SDU received by the Beidou network device 200 may be "0", the total number of frames may be "11", and the frame sequence number may be "00". The SAI value of the second SLC PDU in the first SLC SDU may be "0", the total number of frames may be "11", and the frame sequence number may be "01". The SAI value of the third SLC PDU in the first SLC SDU may be "0", the total number of frames may be "11", and the frame sequence number may be "10". The SAI value of the fourth SLC PDU in the first SLC SDU may be "0", the total number of frames may be "11", and the frame sequence number may be "11". The Beidou network device 200 may splice these four SLC PDUs into the first SLC SDU in ascending order of the frame sequence number, and report it to the MDCP layer as MDCP PDU0 of the MDCP layer. Beidou network device 200 may store MDCP PDU0 in an MDCP layer receiving buffer (MDCP Rxbuffer), wherein the value of the subsequent indication field in MDCP PDU0 is "01".

[0176] The SAI value of the first SLC PDU in the second SLC SDU received by the Beidou network device 200 may be "1", the total number of frames may be "11", and the frame sequence number may be "00". The SAI value of the second SLC PDU in the second SLC SDU may be "1", the total number of frames may be "11", and the frame sequence number may be "01". The SAI value of the third SLC PDU in the second SLC SDU may be "1", the total number of frames may be "11", and the frame sequence number may be "10". The SAI value of the fourth SLC PDU in the second SLC SDU may be "1", the total number of frames may be "11", and the frame sequence number may be "11". The Beidou network device 200 may splice these four SLC PDUs into the second SLC SDU in ascending order of the frame sequence number, and report it to the MDCP layer as MDCP PDU1 of the MDCP layer. The Beidou network device 200 may store the MDCP PDU1 in the MDCP layer receiving buffer (MDCP Rxbuffer), wherein the value of the subsequent indication field in the MDCP PDU1 is "10".

[0177] The SAI value of the first SLC PDU in the third SLC SDU received by the Beidou network device 200 may be "0", the total number of frames may be "11", and the frame sequence number may be "00". The SAI value of the second SLC PDU in the third SLC SDU may be "0", the total number of frames may be "11", and the frame sequence number may be "01". The SAI value of the third SLC PDU in the third SLC SDU may be "0", the total number of frames may be "11", and the frame sequence number may be "10". The SAI value of the fourth SLC PDU in the third SLC SDU may be "0", the total number of frames may be "11", and the frame sequence number may be "11". The Beidou network device 200 may splice these four SLC PDUs into the third SLC SDU in ascending order of the frame sequence number, and report it to the MDCP layer as MDCP PDU2 of the MDCP layer. The Beidou network device 200 may store the MDCP PDU2 in the MDCP layer receiving buffer (MDCP Rxbuffer), wherein the value of the subsequent indication field in the MDCP PDU2 is "11".

[0178] The above examples are only used to explain the present application and should not be construed as limiting.

[0179] 4. The Beidou network device 200 performs protocol parsing of received data at the MDCP layer.

[0180] At the MDCP layer, after receiving all MDCP PDUs of an MDCP SDU sent by the terminal 100, the Beidou network device 200 may aggregate multiple MDCP PDUs in a receiving time sequence based on the successor indication field in the MDCP PDU to obtain an MDCP SDU.

[0181] When the Beidou network device 200 obtains the MDCP PDU with the value of the successor indication field as "11" from the SLC layer, the Beidou network device 200 can take out all MDCP PDUs from the MDCP Rxbuffer, and splice them according to the value of the successor indication field and the order of receiving time, and remove the redundant indication field and padding data after splicing to obtain the MDCP SDU. The Beidou network device 200 can report the MDCP SDU to the application layer through the inter-layer interface as an application layer message.

[0182] The following describes the segmentation process of the MDCP SDU at the MDCP layer during inbound operation.

[0183] The following description takes the example of the terminal 100 segmenting an MDCP SDU into one or more MDCP PDUs. The terminal 100 segmenting an MDCP SDU into one or more MDCP PDUs may include the following steps:

[0184] 1. The data compressed and encrypted by the application layer of the terminal 100 is used as the MDCP SDU of the MDCP layer. The data size of the MDCP SDU can be recorded as DataSizeOfMsdu;

[0185] 2. The terminal 100 can calculate the number of segments SegmentNumOfMsdu of an MDCP SDU, the data portion of each MDCP PDU obtained by segmenting the MDCP SDU, and the padding data according to the transmission capacity provided by the SLC layer; here, the transmission capacity of the SLC layer is obtained from the PHY layer through the inter-layer transmission interface. The transmission capacity of the SLC layer refers to the specific data length of an SLC PDU that the SLC layer can transmit. The data length of an SLC PDU that the SLC layer can transmit is determined according to the data length of a physical frame in the PHY layer.

[0186] 3. The terminal 100 adds padding data and redundant length indication field to the MDCP SDU according to the number of segments SegmentNumOfMsdu and the sequence number of the MDCP PDU, and then segments it into multiple MDCP PDUs, wherein the redundant length indication field is used to indicate the data length of the padding data. Then the terminal 100 determines the subsequent indication of each MDCP PDU, and finally forms a complete MDCP PDU; wherein the subsequent indication needs to indicate the first MDCP PDU, the middle MDCP PDU, and the last MDCP PDU among the multiple MDCP PDUs; if the current SegmentNumOfMsdu=1, the subsequent indication needs to indicate that the current MDCP PDU is a separate MDCP PDU; if SegmentNumOfMsdu=4, the subsequent indication needs 4 states, 2 bits;

[0187] 4. The terminal 100 passes the MDCP PDU to the SLC layer through the inter-layer interface as the SLC SDU of the SLC layer.

[0188] Next, the reassembly process of the MDCP PDU at the MDCP layer upon inbound is introduced.

[0189] The following is an example of the Beidou network device 200 reorganizing one or more received MDCP PDUs into an MDCP SDU. The Beidou network device 200 reorganizing one or more MDCP PDUs into an MDCP SDU may include the following steps:

[0190] 1. At the SLC layer, the Beidou network device 200 can calculate the length of an MDCP PDU data packet based on the frame sequence number and total number of frames carried by the SLC PDU received by the SLC layer, as well as the frame length of an SLC PDU obtained by blind decoding. The Beidou network device 200 reports the calculated length of an MDCP PDU data packet to the MDCP layer.

[0191] Specifically, the inbound physical layer frame length is a fixed frame length of a finite set, so that when the physical layer of the Beidou network device 200 successfully receives the inbound physical layer frame (after each frame length is tried and the decoding is successful), it knows the corresponding physical layer frame length. After the SLC layer receives multiple SLC frames (each SLC frame corresponds to a physical layer frame), the SLC can inform the MDCP layer of the packet length of its SLC SDU, i.e., MDCP PDU.

[0192] Then, the Beidou network device 200 can obtain the length after packetization according to the length of each MDCP PDU, and then obtain the length of padding by parsing the bit indicated by the redundant length, thereby removing the padding bit to obtain the SDU data of MDCP.

[0193] 2. At the MDCP layer, the Beidou network device 200 combines one or more received MDCP PDUs into a complete MDCP SDU data packet according to the subsequent indication field of each MDCP PDU.

[0194] If the subsequent indication field of the MDCP PDU indicates that the MDCP PDU is a single MDCP PDU, the Beidou network device 200 regards the single MDCP PDU as an MDCP SDU data packet.

[0195] If the successor indication bit of the current MDCP PDU indicates that the current MDCP PDU is not the first MDCP PDU among multiple MDCP PDUs, nor is it a single MDCP PDU (i.e., the last MDCP PDU or the middle MDCP PDU among multiple MDCP PDUs), the Beidou network device 200 removes the successor indication field from the currently received MDCP PDU and packages it with the previously received MDCP PDU with the successor indication field removed in sequence. Until the successor indication field of the received MDCP PDU indicates that the current MDCP PDU is the last MDCP PDU, the Beidou network device 200 removes the successor indication field from the last MDCP PDU and packages it with the previously packaged data, and finally obtains an MDCP SDU data packet.

[0196] 3. Beidou network device 200 passes the MDCP SDU to the application layer for processing (such as decryption and decompression, etc.).

[0197] It is understandable that, due to the inbound, the terminal can retransmit, for example, in a transmission process, after the terminal 100 sends SLC PDU0 to the Beidou network device 200, it sends the SLC PDU0 to the Beidou network device 200 again. The Beidou network device 200 needs to determine whether the received SLC PDU is a retransmission. If so, the retransmitted SLC PDU is discarded at the SLC layer. After the Beidou network device 200 receives all the MDCP PDUs of the MDCP layer, it packages them into MDCP SDU packets, parses the redundant length indication field in the MDCP SDU, removes the padding data, and then passes it to the application layer for subsequent decryption and decompression operations.

[0198] Table 2 exemplarily shows that a single MDCP PDU is reassembled into an MDCP SDU.

[0199] Table 2

[0200]

[0201] As shown in Table 2, the Beidou network 200 device combines a single MDCP PDU into an MDCP SDU as an example. The Beidou network device 200 can Figure 3 The length of the MDCP PDU packet is calculated based on the length of the codedata shown in the figure. Then, based on the length of the MDCP PDU, the length of the MDCP SDU can be obtained. As shown in Table 2, taking the coded data (including the code block and the check bit) as 512 bits as an example, the length of the PDU of an SLC layer is also the length of a code block, that is, the length of the coded data minus the length of the check bit (that is, 512 bits-24 bits), which is 488 bits. Among them, the length of the frame header in the SLC PDU is 64 bits, so the length of the S_segment of the SLC layer is (448 bits-64 bits) = 424 bits. When an SLC SDU is divided into only one S_segment, the length of the SLC SDU is also the length of an MDCP PDU, which is 424 bits. The length of the MDCP PDU is also the length of an SLC SDU. When the MDCP SDU contains only one MDCP PDU (including the subsequent indication and M_segment), the length of the subsequent indication (2 bits), the length of the redundant length indication (8 bits) and the length of the MDCP SDU (assuming 177 bits) are subtracted from the length of the MDCP PDU to obtain the padding (237 bits).

[0202] It is understandable that Table 2 is merely an example and does not constitute a limitation on the application embodiments.

[0203] Table 3 exemplarily shows that one MDCP SDU is divided into multiple MDCP PDUs and reassembled.

[0204] Table 3

[0205]

[0206]

[0207] As shown in Table 3, the terminal 100 divides an MDCP SDU into two MDCP PDUs. As shown in Table 3, the terminal 100 receives a data packet at the MDCP layer, which is an MDCP SDU with a data length of 2106 bits. The terminal 100 obtains the coded data (i.e. Figure 3 The data length of the code data shown in FIG. 1 is 512 bits, and the length of the check bit is 24 bits. Therefore, the terminal 100 can determine the transmission capacity that the SLC layer can provide, that is, the data length of an SLC PDU that the SLC layer can transmit is the coded data (i.e. Figure 3 The data length of the codedata shown in the figure minus the length of the check bit and the length of the SLC PDU frame header is 424 bits. Then, the terminal 100 can determine the number of segments of the MDCP SDU according to the data length of an SLC PDU, that is, it can be divided into 2 MDCP PDUs, the data length of each MDCP PDU (the data length of the first MDCP PDU is 1694, and the length of the second MDCP PDU is 422), and the length of the padding (for example, 2 bits).

[0208] It should be understood that Table 3 is merely an example and does not constitute a limitation to the embodiments of the present application.

[0209] The following introduces a protocol encapsulation architecture for outbound data of a Beidou communication system 10 provided in an embodiment of the present application.

[0210] Fig.11A 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 is shown.

[0211] like Fig.11AAs 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.

[0212] 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:

[0213] At the APP layer, the Beidou network device 200 can compress the original data into compressed data through a compression algorithm, and add a compression indication field in front of the compressed data, wherein the compression indication field can be used to indicate the compression algorithm type of the compressed data. Afterwards, the Beidou network device 200 can encrypt the compressed data to obtain encrypted data, and add an encryption algorithm field to the header of the encrypted data, wherein the encryption algorithm field is used to indicate the encryption algorithm type of the encrypted data. The Beidou network device 200 can encapsulate the encrypted data, the compression indication field, and the encryption indication field into an application layer message and send it to the MDCP layer. Among them, the application layer message may include a message header and message data. The message header may include a compression indication field, an encryption indication field, and the like. The message data includes the above-mentioned encrypted data.

[0214] Optionally, in a possible implementation manner, the Beidou network device 200 divides the MDCP SDU into multiple MDCP PDUs at the MDCP layer, and the Beidou network device 200 may transmit the multiple MDCP PDUs to the SLC layer of the Beidou network device 200 together.

[0215] 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 segmented data (M_segement), and add a subsequent indication field to the header of each MDCP segmented data to obtain an MDCP PDU, that is, the MDCP PDU includes an M_segement and a subsequent indication field. Among them, the subsequent indication field can be used to indicate that the current MDCP PDU is the starting MDCP PDU or the middle MDCP PDU or the last MDCP PDU of multiple MDCP PDUs sent continuously; or it is an MDCP PDU sent separately.

[0216] 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 the 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 segment data (S_segement), and add frame header information to each S_segement header to obtain the SLC PDU.

[0217] 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 (such as the version number) of the physical frame as the coding block (code block) of the PHY layer, and add a check bit (for example, a cyclic redundancy check (cyclic redundancy check, CRC) code) at the end of the code block, and encode the code block and the CRC code (for example, polar coding), and the encoded physical frame plus the reserved segment can form a fixed-length physical time slot message branch (S2C_d branch) coded data. 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 forms the pilot coded data of the S2C_d branch and the pilot information of the pilot branch (S2C_p branch), that is, the outbound data. The Beidou network device 200 can send outbound data to the Beidou short message satellite 21 , and forward the data to the terminal 100 via the Beidou short message satellite 21 .

[0218] It is understandable 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.

[0219] The following introduces a protocol parsing architecture for outbound data of a Beidou communication system 10 provided in an embodiment of the present application.

[0220] Fig. 11B 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.

[0221] like Fig. 11B 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 layer (satellite link control protocol, SLC) and a physical layer (physical layer protocol, PHY).

[0222] 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 may be as follows:

[0223] At the PHY layer, the terminal 100 can obtain the modulated and spread pilot coded data sent by the Beidou network device 200. The terminal 100 can despread the received spread spectrum modulated data (spread+modulated data) to obtain the modulated data (modulated data). Then, the terminal 100 can demodulate the modulated data to obtain the pilot coded data (pilot+data). Then, the terminal 100 can remove the pilot information in the pilot coded data to obtain the 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.

[0224] Here, the pilot coded data is the outbound data sent by the above-mentioned Beidou network device 200, and the outbound data is composed of the coded data of the S2C_d branch and the pilot information of the pilot branch (S2C_p branch).

[0225] At the SLC layer, the terminal 100 can splice the 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.

[0226] 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 through the inter-layer interface as an application layer message received by the APP layer.

[0227] 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.

[0228] In the embodiments of the present application, the above-mentioned protocol processing process is only an example for illustration, and the present application does not limit the specific operations of the protocol processing.

[0229] The following describes the segmentation process of the MDCP SDU at the MDCP layer when outbound.

[0230] The following is an example of the Beidou network device 200 segmenting an MDCP SDU into one or more MDCP PDUs. The Beidou network device 200 segmenting an MDCP SDU into one or more MDCP PDUs may include the following steps:

[0231] 1. The data of the application layer of the Beidou network device 200 is compressed and encrypted as the MDCP SDU of the MDCP layer. The data size of the MDCP SDU can be recorded as DataSizeOfMsdu;

[0232] 2. The Beidou network device 200 can calculate the number of segments SegmentNumOfMsdu of an MDCP SDU and the data portion of each MDCP PDU obtained by segmenting the MDCP SDU according to the transmission capacity provided by the SLC layer;

[0233] 3. The Beidou network device 200 determines the subsequent indication of each MDCP PDU according to the number of segments SegmentNumOfMsdu and the sequence number of the MDCP PDU, and finally forms a complete MDCP PDU; wherein the subsequent indication needs to indicate the first MDCP PDU, the middle MDCP PDU, and the last MDCP PDU in multiple MDCP PDUs; if the current SegmentNumOfMsdu=1, the subsequent indication needs to indicate that the current MDCP PDU is a separate MDCP PDU; if SegmentNumOfMsdu=4, the subsequent indication requires 4 states, 2 bits;

[0234] 4. The Beidou network device 200 passes the MDCP PDU to the SLC layer through the inter-layer interface as the SLC SDU of the SLC layer.

[0235] Next, the reassembly process of the MDCP PDU at the MDCP layer during outbound transmission is introduced.

[0236] The following is an example of the terminal 100 reorganizing one or more received MDCP PDUs into an MDCP SDU. The terminal 100 reorganizing one or more received MDCP PDUs into an MDCP SDU may include the following steps:

[0237] 1. At the SLC layer, the terminal 100 can calculate the length of an MDCP PDU data packet according to the frame sequence number and total number of frames carried by the SLC PDU received by the SLC layer, as well as the frame length of an SLC PDU. The terminal 100 reports the calculated length of an MDCP PDU data packet to the MDCP layer.

[0238] 2. At the MDCP layer, the terminal 100 combines one or more received MDCP PDUs into a complete MDCP SDU data packet according to the subsequent indication field of each MDCP PDU.

[0239] If the subsequent indication field of the MDCP PDU indicates that the MDCP PDU is a single MDCP PDU, the terminal 100 regards the single MDCP PDU as an MDCP SDU data packet.

[0240] If the successor indication bit of the current MDCP PDU indicates that the current MDCP PDU is not the first MDCP PDU among multiple MDCP PDUs, nor is it a single MDCP PDU (i.e., the last MDCP PDU or the middle MDCP PDU among multiple MDCP PDUs), the terminal 100 removes the successor indication field from the currently received MDCP PDU and packages it with the previously received MDCP PDU with the successor indication field removed in sequence. Until the successor indication field of the received MDCP PDU indicates that the current MDCP PDU is the last MDCP PDU, the terminal 100 removes the successor indication field from the last MDCP PDU and packages it with the previously packaged data, and finally obtains an MDCP SDU data packet.

[0241] 3. The terminal 100 passes the MDCP SDU to the application layer for processing (eg, decryption and decompression, etc.).

[0242] The following describes a method for controlling data transmission in a Beidou communication system provided in an embodiment of the present application.

[0243] Fig. 11C A flow chart of a data transmission control method in a Beidou communication system provided in an embodiment of the present application is shown.

[0244] like Fig. 11C As shown, the data transmission control method in the Beidou communication system may include:

[0245] S1101. The terminal 100 adds padding data and redundant length indication fields to a first message data convergence layer service data unit MDCP SDU at the message data convergence layer MDCP layer, and then divides the first message data convergence layer service protocol data unit MDCP PDU into M data convergence layer service protocol data units MDCP PDU.

[0246] Wherein, M is a positive integer; the redundant length indication field is used to indicate the data length of the padding data, the M 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 M MDCP PDUs; the terminal sends the first MDCP PDU to the Beidou network device.

[0247] Among them, in one possible implementation, M is greater than 1, the successor indication field of the first MDCP PDU is a first value, and the first value is used to indicate that the first MDCP PDU is the first MDCP PDU among M MDCP PDUs; M is greater than 1, the successor indication field of the first MDCP PDU is a second value, and the second value is used to indicate that the first MDCP PDU is the middle MDCP PDU among the M MDCP PDUs; M is greater than 1, the successor indication field of the first MDCP PDU is a third value, and the third value is used to indicate that the first MDCP PDU is the last MDCP PDU among the M MDCP PDUs.

[0248] In a possible implementation manner, M is 1, and the successor indication field of the first MDCP PDU is a fourth value, and the fourth value is used to indicate that the first MDCP PDU is a separate MDCP PDU.

[0249] S1102 . The terminal 100 sends a first MDCP PDU to the Beidou network device 200 .

[0250] S1103 . The Beidou network device 200 receives M data convergence layer service protocol data units MDCP PDUs sent by the terminal 100 .

[0251] S1104. The Beidou network device 200 splices the M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer.

[0252] Some possible implementations performed by the terminal 100 are introduced below.

[0253] In a possible implementation, the terminal 100 adds padding data and a redundant length indication field to a first message data convergence layer service data unit MDCP SDU at a message data convergence MDCP layer, and divides the first message data convergence layer service data unit MDCP SDU into M data convergence layer service protocol data units MDCP PDU, specifically including: the terminal 100 generates an application layer message at an application layer; the terminal 100 uses the application layer message as a first MDCP SDU at the MDCP layer, and after adding padding data and a redundant length indication field to the first MDCP SDU, divides the first MDCP SDU into M MDCP PDUs.

[0254] In a possible implementation, the terminal 100 uses the application layer message as the first MDCP SDU at the MDCP layer, and after adding padding data and a redundant length indication field to the first MDCP SDU and before dividing it into M MDCP PDUs, the method further includes: the terminal 100 obtains original data; the terminal 100 compresses the original data at the application layer to obtain compressed data; the terminal 100 encrypts the compressed data at the application layer to obtain encrypted data; the terminal 100 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.

[0255] In a possible implementation, the terminal 100 sends the first MDCP PDU to the Beidou network device, specifically including: the terminal 100 transmits the first MDCP PDU to the satellite link control SLC layer as the first satellite link control layer service data unit SLC SDU of the SLC layer; the terminal 100 divides the first SLC SDU into N satellite link control layer protocol data units SLC PDU at the SLC layer, where N is a positive integer; wherein the N SLC PDUs include the first SLC PDU, and the frame header information of the first SLC PDU includes a service data unit alternation indication SAI field, a total number of frames field, and a frame sequence number field; the SAI field is used to indicate whether the first SLC PDU is retransmission data, the total number of frames field is used to indicate the total number N of SLC PDUs included in the first SLC SDU, and the frame sequence number field is used to indicate the frame sequence number of the first SLC PDU in the first SLC SDU; the terminal 100 sends the first SLC PDU to the Beidou network device.

[0256] In this way, whether the SLC PDU is retransmitted data is indicated by flipping the value of the SAI field of the SLC PDU, which can ensure that the Beidou network device can identify whether the received SLC PDU is retransmitted data, thereby ensuring continuous data transmission in the Beidou communication system.

[0257] In a possible implementation, the terminal 100 sends the first SLC PDU to the Beidou network device, which specifically includes: the terminal 100 sends the first SLC PDU from the SLC layer to the physical PHY layer as the first coding block of the PHY layer; the terminal 100 adds check bit information at the end of the first coding block at the PHY layer, and encodes the first coding block and the check bit information to obtain first coded data; the terminal 100 inserts pilot information into the first coded data at the PHY layer to obtain first pilot data; the terminal 100 modulates the first pilot data and the synchronization header of the first pilot data at the PHY layer to obtain first modulated data and a first modulation synchronization header; the terminal 100 spreads the first modulated data and the modulation synchronization header at the PHY layer to obtain first spread spectrum modulated data; the terminal 100 sends the first spread spectrum modulated data as the first physical frame to the Beidou network device at the PHY layer.

[0258] In a possible implementation manner, the terminal 100 determines the data length of the first MDCP PDU according to the data length of the first MDCP SDU and the data length of the first physical frame.

[0259] In this way, the terminal 100 can know how to split the MDCP SDU into multiple MDCP PDUs.

[0260] Some possible implementations of the Beidou network device 200 are introduced below.

[0261] In a possible implementation, the Beidou network device 200 splices the M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer, including: when the second MDCP PDU received by the Beidou network device 200 subsequently indicates that the second MDCP PDU is the last one of the M MDCP PDUs, the Beidou network device 200 splices the M MDCP PDUs into a first MDCP SDU at the MDCP layer, and reports the first MDCP SDU as an application layer message from the MDCP layer to the application layer.

[0262] 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 100 when compressing the original data into compressed data, and the encryption indication field is used to indicate the encryption algorithm used by the terminal 100 when encrypting the compressed data into encrypted data; the method also includes: the Beidou network device 200 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 Beidou network device 200 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.

[0263] In a possible implementation, it also includes: the Beidou network device 200 splices N SLC PDUs into a first SLC SDU at the SLC layer, and reports the first SLC SDU as the first MDCP PDU from the SLC layer of the Beidou network device 200 to the MDCP layer of the Beidou network device 200; wherein the N SLC PDUs include the first SLC PDU, and the frame header information of the first SLC PDU includes a service data unit alternating indication SAI field, a total number of frames field, and a frame sequence number field; the SAI field is used to indicate whether the first SLC PDU is retransmitted data, the total number of frames field is used to indicate the total number N of SLC PDUs included in the first SLC SDU, and the frame sequence number field is used to indicate the frame sequence number of the first SLC PDU in the first SLC SDU.

[0264] In a possible implementation, the Beidou network device 200 concatenates N SLC PDUs into a first SLC SDU at the SLC layer, and uses the first SLC SDU as the first MDCP Before the PDU is reported from the SLC layer of the Beidou network device 200 to the MDCP layer of the Beidou network device 200, the method also includes: the Beidou network device 200 obtains the first spread spectrum modulation data sent by the terminal 100 at the PHY layer; the Beidou network device 200 despreads the first spread spectrum modulation data at the PHY layer to obtain the first modulation data and the first modulation synchronization header; the Beidou network device 200 demodulates the first modulation data and the first modulation synchronization header at the PHY layer to obtain the first pilot data and the first synchronization header; the Beidou network device 200 removes the pilot information in the first pilot data at the PHY layer to obtain the first coded data; the Beidou network device 200 decodes the first coded data at the PHY layer to obtain the first coded block and the first verification information; the Beidou network device 200 verifies the first coded block based on the first verification information at the PHY layer, and after the verification is successful, uses the first coded block as the first SLC in the first SLC SDU in the SLC layer of the Beidou network device 200 The PDU is presented from the PHY layer to the SLC layer of the Beidou network device 200 .

[0265] In a possible implementation, the Beidou network device 200 splices M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer, including: after the Beidou network device 200 removes the successor indication field of each MDCP PDU in the M MDCP PDUs at the MDCP layer, the M MDCP PDUs are spliced ​​into a first MDCP SDU in the order indicated by the successor indication of each MDCP PDU in the M MDCP PDUs.

[0266] Fig.11D A flow chart of a data transmission control method in a Beidou communication system provided in an embodiment of the present application is shown.

[0267] like Fig.11D As shown, the data transmission control method in the Beidou communication system may include:

[0268] S2101. The Beidou network device 200 divides a first message data convergence layer service data unit MDCP SDU into M data convergence layer service protocol data units MDCP PDU at the message data convergence layer MDCP layer.

[0269] Wherein, M is a positive integer; the M MDCP PDUs include a first MDCP PDU, 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 M MDCP PDUs; the Beidou network device 200 sends the first MDCP PDU.

[0270] Among them, in one possible implementation, M is greater than 1, the successor indication field of the first MDCP PDU is a first value, and the first value is used to indicate that the first MDCP PDU is the first MDCP PDU among M MDCP PDUs; M is greater than 1, the successor indication field of the first MDCP PDU is a second value, and the second value is used to indicate that the first MDCP PDU is the middle MDCP PDU among the M MDCP PDUs; M is greater than 1, the successor indication field of the first MDCP PDU is a third value, and the third value is used to indicate that the first MDCP PDU is the last MDCP PDU among the M MDCP PDUs.

[0271] In a possible implementation manner, M is 1, and the successor indication field of the first MDCP PDU is a fourth value, and the fourth value is used to indicate that the first MDCP PDU is a separate MDCP PDU.

[0272] S2102 . The Beidou network device 200 sends a first MDCP PDU to the terminal 100 .

[0273] S2103 . The terminal 100 receives M data convergence layer service protocol data units MDCP PDU sent by the Beidou network device 200 .

[0274] S2104. The terminal 100 concatenates the M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer.

[0275] Some possible implementations of the Beidou network device 200 are introduced below.

[0276] In a possible implementation, the Beidou network device 200 divides the first message data convergence layer service data unit MDCP SDU into M data convergence layer service protocol data units MDCP PDU at the message data convergence MDCP layer, specifically including: the Beidou network device 200 generates an application layer message at the application layer; the Beidou network device 200 uses the application layer message as the first MDCP SDU at the MDCP layer, and divides the first MDCP SDU into M MDCP PDUs.

[0277] In a possible implementation, the Beidou network device 200 generates an application layer message at the application layer, specifically including: the Beidou network device 200 obtains 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.

[0278] In a possible implementation, the Beidou network device 200 sends the first MDCP PDU, specifically including: the Beidou network device 200 transmits the first MDCP PDU to the satellite link control SLC layer as the first satellite link control layer service data unit SLC SDU of the SLC layer; the Beidou network device 200 divides the first SLC SDU into N satellite link control layer protocol data units SLC PDU at the SLC layer, where N is a positive integer; wherein the N SLC PDUs include a first SLC PDU, and the frame header information of the first SLC PDU includes a first user ID field and a first frame type field, the first user ID field is used to indicate the terminal 100 receiving the first user frame, and the first frame type field is used to indicate the frame type of the first user frame; the Beidou network device 200 sends the first SLC PDU.

[0279] In a possible implementation, the Beidou network device 200 sends a first physical frame and a second physical frame, including: the Beidou network device 200 adds a first check bit information at the end of the first physical frame at the PHY layer, encodes the first physical frame and the first check bit information to obtain first coded data, adds a second check bit information at the end of the second physical frame, and encodes the second physical frame and the second check bit information to obtain second 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, and modulates the second coded data and the second reserved field of the second coded data to obtain second modulated data; the Beidou network device 200 spreads the first modulated data at the PHY layer to obtain first spread spectrum modulated data, and spreads the second modulated data to obtain second 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, as well as the second spread spectrum modulated data and the second pilot information of the second spread spectrum modulated data at the PHY layer.

[0280] In a possible implementation manner, the method further includes: the Beidou network device 200 determines the data length of the first MDCP PDU according to the data length of the first MDCP SDU and the data length of the first physical frame.

[0281] In this way, the Beidou network device 200 can know how to split the MDCP SDU into multiple MDCP PDUs.

[0282] Some possible implementations performed by the terminal 100 are introduced below.

[0283] In a possible implementation, the terminal 100 splices M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer, including: when the second MDCP PDU received by the terminal 100 subsequently indicates that the second MDCP PDU is the last one of the M MDCP PDUs, the terminal 100 splices the M MDCP PDUs into a first MDCP SDU at the MDCP layer, and reports the first MDCP SDU from the MDCP layer to the application layer as an application layer message.

[0284] 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 100 when compressing original data into compressed data, and the encryption indication field is used to indicate the encryption algorithm used by the terminal 100 when encrypting 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.

[0285] In a possible implementation, the method may also include: the Beidou network device 200 splices N SLC PDUs into a first SLC SDU at the SLC layer, and reports the first SLC SDU as a first MDCP PDU from the SLC layer of the Beidou network device 200 to the MDCP layer of the Beidou network device 200; wherein the N SLC PDUs include the first SLC PDU, the frame header information of the first SLC PDU includes a first user ID field and a first frame type field, the first user ID field is used to indicate the terminal 100 receiving the first user frame, and the first frame type field is used to indicate the frame type of the first user frame.

[0286] In a possible implementation, the terminal 100 concatenates N SLC PDUs into a first SLC SDU at the SLC layer, and uses the first SLC SDU as the first MDCP Before the PDU is reported from the SLC layer of the Beidou network device 200 to the MDCP layer of the Beidou network device 200, the method may also include: the terminal 100 obtains the first spread spectrum modulation data sent by the terminal 100 at the PHY layer; the terminal 100 despreads the first spread spectrum modulation data at the PHY layer to obtain the first modulation data and the first modulation synchronization header; the terminal 100 demodulates the first modulation 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 200 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, presents the first user frame in the first coded block whose ID field is the same as the ID of the terminal 100 as the first SLCPDU 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.

[0287] In a possible implementation, the terminal 100 splices M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer, including: after the terminal 100 removes the successor indication field of each MDCP PDU in the M MDCP PDUs at the MDCP layer, the M MDCP PDUs are spliced ​​into a first MDCP SDU in an order indicated by the successor indication of each MDCP PDU in the M MDCP PDUs.

[0288] The following first introduces an exemplary terminal 100 provided in an embodiment of the present application.

[0289] Fig.12 It is a schematic diagram of the structure of the terminal 100 provided in an embodiment of the present application.

[0290] The embodiment is described in detail below by taking terminal 100 as an example. It should be understood that terminal 100 may have more or fewer components than those shown in the figure, may combine two or more components, or may have different component configurations. The various components shown in the figure may be implemented in hardware, software, or a combination of hardware and software including one or more signal processing and / or application specific integrated circuits.

[0291] 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.

[0292] It is to be understood that the structure illustrated in the embodiment of the present application does not constitute a specific limitation on the terminal 100. In other embodiments of the present application, the terminal 100 may include more or fewer components than shown in the figure, or combine certain components, or split certain components, or arrange the components differently. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0293] 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 processor (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), etc. Different processing units may be independent devices or integrated into one or more processors.

[0294] 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.

[0295] The processor 110 may also be provided with a memory for storing instructions and data. In some embodiments, the memory in the processor 110 is a cache memory. The memory may store instructions or data that the processor 110 has just used or cyclically used. If the processor 110 needs to use the instruction or data again, it may be directly called from the memory. This avoids repeated access, reduces the waiting time of the processor 110, and thus improves the efficiency of the system.

[0296] In some embodiments, the processor 110 may include one or more interfaces. The interface 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, etc.

[0297] The I2C interface is a bidirectional synchronous serial bus, including a serial data line (SDA) and a serial clock line (SCL). In some embodiments, the processor 110 may include multiple groups of I2C buses. The processor 110 may be coupled to the touch sensor 180K, the charger, the flash, the camera 193, etc. through different I2C bus interfaces. For example, the processor 110 may be coupled to the touch sensor 180K through the I2C interface, so that the processor 110 communicates with the touch sensor 180K through the I2C bus interface, thereby realizing the touch function of the terminal 100.

[0298] 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 achieve communication between the processor 110 and the audio module 170. In some embodiments, the audio module 170 can transmit an audio signal to the wireless communication module 160 via the I2S interface to achieve the function of answering a call through a Bluetooth headset.

[0299] 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 to realize the function of answering calls via a Bluetooth headset. Both the I2S interface and the PCM interface can be used for audio communication.

[0300] The UART interface is a universal serial data bus for asynchronous communication. The 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 generally 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 through the UART interface to implement the Bluetooth function. In some embodiments, the audio module 170 can transmit an audio signal to the wireless communication module 160 through the UART interface to implement the function of playing music through a Bluetooth headset.

[0301] The MIPI interface can be used to connect the processor 110 with peripheral devices such as the display screen 194 and the camera 193. The MIPI interface includes a camera serial interface (CSI), a display serial interface (DSI), etc. In some embodiments, the processor 110 and the camera 193 communicate via the CSI interface to implement the shooting function of the terminal 100. The processor 110 and the display screen 194 communicate via the DSI interface to implement the display function of the terminal 100.

[0302] The GPIO interface can be configured by software. The GPIO interface can be configured as a control signal or as a data signal. In some embodiments, the GPIO interface can be used to connect the processor 110 with the camera 193, the display 194, the wireless communication module 160, the audio module 170, the 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.

[0303] 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.

[0304] The USB interface 130 is an interface that complies with the USB standard specification, and specifically can be a Mini USB interface, a Micro USB interface, a USB Type C interface, etc. The USB interface 130 can be used to connect a charger to charge the terminal 100, and can also be used to transmit data between the terminal 100 and peripheral devices. It can also be used to connect headphones to play audio through the headphones. The interface can also be used to connect other electronic devices, such as AR devices, etc.

[0305] It is understandable that the interface connection relationship between the modules illustrated in the embodiment of the present application is only a schematic illustration and does not constitute a structural limitation on the terminal 100. In other embodiments of the present application, the terminal 100 may also adopt different interface connection methods in the above embodiments, or a combination of multiple interface connection methods.

[0306] The charging management module 140 is used to receive charging input from a charger, where the charger can be a wireless charger or a wired charger.

[0307] 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 power the processor 110, the internal memory 121, the external memory, the display screen 194, the camera 193, and the wireless communication module 160.

[0308] 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.

[0309] 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 the utilization of the antennas. For example, antenna 1 can be reused as a diversity antenna for a wireless local area network. In some other embodiments, the antenna can be used in combination with a tuning switch.

[0310] 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.

[0311] The modem processor may include a modulator and a demodulator. Among them, the modulator is used to modulate the low-frequency baseband signal to be sent 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 the low-frequency baseband signal is processed by the baseband processor, it is passed to the application processor. The application processor outputs a sound signal through an audio device (not limited to a speaker 170A, a receiver 170B, etc.), or displays an image or video through a 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.

[0312] The wireless communication module 160 can provide wireless communication solutions 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., which are applied to the terminal 100. 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, modulates the frequency of the electromagnetic wave signal and filters it, and sends the processed signal to the processor 110. The wireless communication module 160 can also receive the signal to be sent from the processor 110, modulate the frequency of it, amplify it, and convert it into electromagnetic waves for radiation through the antenna 2.

[0313] 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).

[0314] The terminal 100 can communicate with the Beidou network device 200 through the Beidou communication technology. Optionally, the Beidou communication technology can exist in an independent chip, or can be integrated in the wireless communication module 160.

[0315] The terminal 100 implements the display function through a GPU, a display screen 194, and an application processor. The GPU is a microprocessor for image processing, which connects the display screen 194 and the application processor. The GPU is used to perform mathematical and geometric calculations for graphics rendering. The processor 110 may include one or more GPUs that execute program instructions to generate or change display information.

[0316] The display screen 194 is used to display images, videos, etc. The display screen 194 includes a display panel. The display panel can be a liquid crystal display (LCD), an organic light-emitting diode (OLED), an active-matrix organic light emitting diode or an active-matrix organic light emitting diode (AMOLED), a flexible light-emitting diode (FLED), Miniled, MicroLed, Micro-oLed, a quantum dot light-emitting diode (QLED), etc. In some embodiments, the terminal 100 may include 1 or N display screens 194, where N is a positive integer greater than 1.

[0317] The terminal 100 can realize the shooting function through the ISP, the camera 193, the video codec, the GPU, the display screen 194 and the application processor.

[0318] ISP is used to process the data fed back by camera 193. For example, when taking a photo, the shutter is opened, and the light is transmitted to the camera photosensitive element through the lens. The light signal is converted into an electrical signal, and the camera photosensitive element transmits the electrical signal to ISP for processing and converts it into an image visible to the naked eye. ISP can also perform algorithm optimization on the noise, brightness, and color of the image. ISP can also optimize the exposure, color temperature and other parameters of the shooting scene. In some embodiments, ISP can be set in camera 193.

[0319] 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 optical signal into an electrical signal, and then passes the electrical signal to the ISP to be converted 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.

[0320] The digital signal processor is used to process digital signals, and can process not only digital image signals but also other digital signals. For example, when the terminal 100 is selecting a frequency point, the digital signal processor is used to perform Fourier transform on the frequency point energy.

[0321] Video codecs are used to compress or decompress digital videos. Terminal 100 may support one or more video codecs. Thus, terminal 100 may play or record videos in various coding formats, such as moving picture experts group (MPEG) 1, MPEG2, MPEG3, MPEG4, etc.

[0322] NPU is a neural network (NN) computing processor. By drawing on the structure of biological neural networks, such as the transmission mode between neurons in the human brain, it can quickly process input information and can also continuously self-learn. Through NPU, applications such as intelligent cognition of the terminal 100 can be realized, such as image recognition, face recognition, voice recognition, text understanding, etc.

[0323] The internal memory 121 may include one or more random access memories (RAM) and one or more non-volatile memories (NVM).

[0324] 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 DDR SDRAM is generally referred to as DDR5 SDRAM), etc.;

[0325] Non-volatile memory may include disk storage devices and flash memory.

[0326] Flash memory can be divided into NOR FLASH, NAND FLASH, 3D NAND FLASH, etc. according to the operating principle; can be divided into single-level cell (SLC), multi-level cell (MLC), triple-level cell (TLC), quad-level cell (QLC), etc. according to the storage unit potential level; can be divided into universal flash storage (UFS), embedded multi media card (eMMC), etc. according to the storage specification.

[0327] 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.

[0328] 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 .

[0329] The terminal 100 can implement audio functions such as music playing and recording through the audio module 170, the speaker 170A, the receiver 170B, the microphone 170C, the earphone interface 170D, and the application processor.

[0330] 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 arranged in the processor 110, or some functional modules of the audio module 170 can be arranged in the processor 110.

[0331] The speaker 170A, also called a "speaker", is used to convert an audio electrical signal into a sound signal. The terminal 100 can listen to music or listen to a hands-free call through the speaker 170A.

[0332] 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 received by placing the receiver 170B close to the ear.

[0333] Microphone 170C, also called "microphone" or "microphone", is used to convert sound signals into electrical signals. When making a call or sending a voice message, the user can make a sound by putting his mouth close to microphone 170C to input the sound signal into microphone 170C. Terminal 100 may be provided with at least one microphone 170C. In other embodiments, terminal 100 may be provided with two microphones 170C, which can not only collect sound signals but also realize noise reduction function. In other embodiments, terminal 100 may also be provided with three, four or more microphones 170C to realize collection of sound signals, noise reduction, identification of sound source, realization of directional recording function, etc.

[0334] The earphone interface 170D is used to connect a wired earphone and can be a USB interface 130 or a 3.5 mm open mobile terminal platform (OMTP) standard interface or a cellular telecommunications industry association of the USA (CTIA) standard interface.

[0335] The pressure sensor 180A is used to sense the pressure signal and can convert the pressure signal into an electrical signal. In some embodiments, the pressure sensor 180A can be set on the display screen 194. There are many types of pressure sensors 180A, such as resistive pressure sensors, inductive pressure sensors, capacitive pressure sensors, etc. The capacitive pressure sensor can be a parallel plate including at least two conductive materials. When a force acts on the pressure sensor 180A, the capacitance between the electrodes changes. The terminal 100 determines the intensity of the pressure according to the change in capacitance. When a touch operation acts on the display screen 194, the terminal 100 detects the touch operation intensity according to the pressure sensor 180A. The terminal 100 can also calculate the touch position according to the detection signal of the pressure sensor 180A. In some embodiments, touch operations acting on the same touch position but with different touch operation intensities can correspond to different operation instructions. For example: when a touch operation with a touch operation intensity less than the first pressure threshold acts on the short message application icon, an instruction to view the short message is executed. When a touch operation with a touch operation intensity greater than or equal to the first pressure threshold acts on the short message application icon, an instruction to create a new short message is executed.

[0336] 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. Exemplarily, 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.

[0337] The air pressure sensor 180C is used to measure air pressure. In some embodiments, the terminal 100 calculates the altitude through the air pressure value measured by the air pressure sensor 180C to assist positioning and navigation.

[0338] 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 leather 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 according to the magnetic sensor 180D. Then, according to the detected opening and closing state of the leather case or the opening and closing state of the flip cover, the flip cover automatic unlocking and other features are set.

[0339] The acceleration sensor 180E can detect the magnitude of the acceleration of the terminal 100 in various directions (generally three axes). When the terminal 100 is stationary, the magnitude and direction of gravity can be detected. It can also be used to identify the posture of the electronic device and is applied to applications such as horizontal and vertical screen switching and pedometers.

[0340] The distance sensor 180F is used to measure the distance. The terminal 100 can measure the distance by infrared or laser. In some embodiments, when shooting a scene, the terminal 100 can use the distance sensor 180F to measure the distance to achieve fast focusing.

[0341] 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 a 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 that 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.

[0342] The ambient light sensor 180L is used to sense the ambient light brightness. The terminal 100 can adaptively adjust the brightness of the display screen 194 according to the perceived ambient light brightness. The ambient light sensor 180L can also be used to automatically adjust the white balance when taking pictures. The ambient light sensor 180L can also cooperate with the proximity light sensor 180G to detect whether the terminal 100 is in a pocket to prevent accidental touches.

[0343] 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.

[0344] The temperature sensor 180J is used to detect temperature. In some embodiments, the terminal 100 uses the temperature detected by the temperature sensor 180J to execute a temperature processing strategy. For example, when the temperature reported by the temperature sensor 180J exceeds a threshold, the terminal 100 reduces the performance of the processor located near the temperature sensor 180J to reduce power consumption and implement thermal protection. In other embodiments, when the temperature is lower than another threshold, the terminal 100 heats the battery 142 to avoid abnormal shutdown of the terminal 100 due to low temperature. In other embodiments, when the temperature is lower than another threshold, the terminal 100 performs a boost on the output voltage of the battery 142 to avoid abnormal shutdown caused by low temperature.

[0345] The touch sensor 180K is also called a "touch panel". The touch sensor 180K can be arranged on the display screen 194, and 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 acting on or near it. The touch sensor can pass the detected touch operation to the application processor to determine the type of touch event. Visual output related to the touch operation can be provided through the display screen 194. In other embodiments, the touch sensor 180K can also be arranged on the surface of the terminal 100, which is different from the position of the display screen 194.

[0346] The key 190 includes a power key, a volume key, etc. The key 190 may be a mechanical key or a touch key. The terminal 100 may receive key input and generate key signal input related to user settings and function control of the terminal 100.

[0347] 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.

[0348] Indicator 192 may be an indicator light, which may be used to indicate charging status, power changes, messages, missed calls, notifications, etc.

[0349] The SIM card interface 195 is used to connect a SIM card. The SIM card can be connected to or disconnected from the terminal 100 by inserting the SIM card interface 195 or pulling the SIM card interface 195 out. The terminal 100 can support 1 or N SIM card interfaces, where N is a positive integer greater than 1. The SIM card interface 195 can support Nano SIM cards, Micro SIM cards, SIM cards, and the like. Multiple cards can be inserted into the same SIM card interface 195 at the same time. The types of the multiple cards can be the same or different. The SIM card interface 195 can also be compatible with different types of SIM cards. The SIM card interface 195 can also be 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.

[0350] 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.

[0351] The embodiment of the present application can divide the terminal 100 and the Beidou network device 200 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 integrated module 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 function division. There may be other division methods in actual implementation.

[0352] The following will be combined Figures 13 to 16 The communication device according to the embodiment of the present application is described in detail.

[0353] In the case of integrated units, see Fig.13 , Fig.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. Fig.13 As shown, the communication device 1300 may include a transceiver unit 1310 and a processing unit 1320 .

[0354] In one design, the transceiver unit 1310 may be used to receive the MDCP PDU sent by the Beidou network device 200 , and also to send the MDCP PDU to the Beidou network device 200 .

[0355] The processing unit 1320 may be configured to divide the first message data convergence layer service data unit MDCP SDU into M data convergence layer service protocol data units MDCP PDUs after adding padding data and redundant length indication fields to the first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer.

[0356] The processing unit 1320 may be further configured to splice the M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer.

[0357] Optionally, the transceiver unit 1310 may also be used to perform the above Fig. 11C and Fig.11D The terminal 100 in the illustrated method embodiment performs the functional steps related to sending and receiving.

[0358] Optionally, the processing unit 1320 may also be used to execute the above Fig. 11C and Fig.11D The method embodiment shown includes the functional steps of protocol parsing and encapsulation and calculation determination performed by the terminal 100.

[0359] 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, and for the sake of brevity, they will not be repeated here.

[0360] In the case of integrated units, see Fig.14 , Fig.14 1 is a schematic diagram of the structure of the communication device 1400 provided in the 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. Fig.14 As shown, the communication device 1400 may include a transceiver unit 1410 and a processing unit 1420 .

[0361] In one design, the transceiver unit 1410 may be used to send the MDCP PDU to the terminal 100, and receive the MDCP PDU sent by the terminal 100.

[0362] The processing unit 1420 may be configured to divide the first message data convergence layer service data unit MDCP SDU into M data convergence layer service protocol data units MDCP PDUs at the message data convergence layer MDCP layer.

[0363] Wherein, M is a positive integer; the M MDCP PDUs include a first MDCP PDU, 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 M MDCP PDUs; the Beidou network device 200 sends the first MDCP PDU.

[0364] Among them, in one possible implementation, M is greater than 1, the successor indication field of the first MDCP PDU is a first value, and the first value is used to indicate that the first MDCP PDU is the first MDCP PDU among M MDCP PDUs; M is greater than 1, the successor indication field of the first MDCP PDU is a second value, and the second value is used to indicate that the first MDCP PDU is the middle MDCP PDU among the M MDCP PDUs; M is greater than 1, the successor indication field of the first MDCP PDU is a third value, and the third value is used to indicate that the first MDCP PDU is the last MDCP PDU among the M MDCP PDUs.

[0365] In a possible implementation manner, M is 1, and the successor indication field of the first MDCP PDU is a fourth value, and the fourth value is used to indicate that the first MDCP PDU is a separate MDCP PDU.

[0366] The processing unit 1420 may also be configured to splice the M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer.

[0367] Optionally, the transceiver unit 1410 may also be used to perform the above Fig. 11C and Fig.11D The method embodiment shown is a method in which the Beidou network device 200 performs the functional steps of sending and receiving.

[0368] Optionally, the processing unit 1420 may also be used to execute the above Fig. 11C and Fig.11D The method embodiment shown includes the functional steps of protocol parsing and encapsulation and calculation determination performed by the Beidou network device 200.

[0369] It should be understood that the communication device 1400 in this design can correspond to the method steps executed by the Beidou network device 200 in the aforementioned embodiment, and for the sake of brevity, they will not be repeated here.

[0370] The above describes the terminal 100 and the Beidou network device 200 of the embodiment of the present application. It should be understood that any device having the above Fig.12 Any product having the functions of the terminal 100 as described above Fig.13 Any form of product that has the functions of the Beidou network device 200 falls within the protection scope of the embodiments of the present application.

[0371] As a possible product form, the terminal 100 described in the embodiment of the present application can be implemented by a general bus architecture.

[0372] See also Fig.15 , Fig.15 1 is a schematic diagram of the structure of a communication device 1500 provided in an embodiment of the present application. The communication device 1500 may be a terminal 100, or a device therein. Fig.15 As shown, the communication device 1500 includes a processor 1501 and a transceiver 1502 connected to the processor for communication. Among them, the processor 1501 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 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., for realizing the transceiver function. The transceiver 1502 may include a receiver and a transmitter, the receiver can be called a receiver or a receiving circuit, etc., for realizing the receiving function; the transmitter can be called a transmitter or a transmitting circuit, etc., for realizing the transmitting function. Optionally, the communication device 1500 may also include an antenna 1503 and / or a radio frequency unit (not shown in the figure). 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 1503 and / or the radio frequency unit may be remotely or distributedly deployed.

[0373] Optionally, the communication device 1500 may include one or more memories 1504, on which instructions may be stored, and the instructions may be computer programs, and the computer programs may be run on the communication device 1500, so that the communication device 1500 performs the method described in the above method embodiment. Optionally, data may also be stored in the memory 1504. The communication device 1500 and the memory 1504 may be provided separately or integrated together.

[0374] The processor 1501 , the transceiver 1502 , and the memory 1504 may be connected via a communication bus.

[0375] In one design, the communication device 1500 may be used to perform the functions of the terminal 100 in the above-mentioned embodiment: the processor 1501 may be used to perform the above-mentioned Fig. 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 for the technology described herein; the transceiver 1502 can be used to perform the above Fig. 11C and Fig.11D The terminal 100 in the illustrated embodiment performs protocol parsing and encapsulation as well as computationally determined functional steps and / or other processes for the technology described herein.

[0376] In any of the above designs, the processor 1501 may include a transceiver for implementing the receiving and sending 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 sending functions may be separate or integrated. The above transceiver circuit, interface, or interface circuit may be used for reading and writing code / data, or the above transceiver circuit, interface, or interface circuit may be used for transmitting or delivering signals.

[0377] In any of the above designs, the processor 1501 may store instructions, which may be computer programs. The computer programs run on the processor 1501, and may enable the communication device 1500 to perform the method steps performed by the terminal 100 in the above method embodiment. The computer program may be fixed in the processor 1501, in which case the processor 1501 may be implemented by hardware.

[0378] 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 the present application can be implemented in 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 channelmetal oxide semiconductor, PMOS), bipolar junction transistor (bipolar junction transistor, BJT), bipolar CMOS (BiCMOS), silicon germanium (SiGe), gallium arsenide (GaAs), etc.

[0379] 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. Fig.15 The communication device 1500 may be an independent device or may be part of a larger device. For example, the communication device 1500 may be:

[0380] (1) Independent integrated circuit IC, or chip, or chip system or subsystem;

[0381] (2) having a set of one or more ICs, and optionally, the IC set may also include a storage component for storing data and computer programs;

[0382] (3) ASIC, such as modem;

[0383] (4) Modules that can be embedded in other devices;

[0384] (5) Receivers, terminals, smart terminals, cellular phones, wireless devices, handheld devices, mobile units, vehicle-mounted devices, network devices, cloud devices, artificial intelligence devices, etc.;

[0385] (6)Others

[0386] 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.

[0387] See also Fig.16 , Fig.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. Fig.16 As shown, the communication device 1600 includes a processor 1601 and a transceiver 1602 connected to the internal communication of the processor. Among them, 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 realizing the transceiver function. The transceiver 1602 may include a receiver and a transmitter, the receiver can be called a receiver or a receiving circuit, etc., for realizing the receiving function; the transmitter can be called a transmitter or a transmitting circuit, etc., for realizing the transmitting function. Optionally, the communication device 1600 may also include an antenna 1603 and / or a radio frequency unit (not shown in the figure). 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.

[0388] Optionally, the communication device 1600 may include one or more memories 1604, on which instructions may be stored, and the instructions may be computer programs, and the computer programs may be run on the communication device 1600, so that the communication device 1600 performs the method described in the above method embodiment. Optionally, data may also be stored in the memory 1604. The communication device 1600 and the memory 1604 may be provided separately or integrated together.

[0389] The processor 1601 , the transceiver 1602 , and the memory 1604 may be connected via a communication bus.

[0390] In one design, the communication device 1600 can be used to perform the functions of the Beidou network device 200 in the above-mentioned embodiment: the processor 1601 can be used to perform the above-mentioned Fig. 11C and Fig.11DIn 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 for the technology described herein; the transceiver 1602 can be used to perform the above Fig. 11C and Fig.11D The Beidou network device 200 in the illustrated embodiment performs relevant protocol parsing and encapsulation and computationally determined functional steps and / or other processes for the technology described herein.

[0391] In any of the above designs, the processor 1601 may include a transceiver for implementing the receiving and sending 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 sending functions may be separate or integrated. The above transceiver circuit, interface, or interface circuit may be used for reading and writing code / data, or the above transceiver circuit, interface, or interface circuit may be used for transmitting or delivering signals.

[0392] In any of the above designs, the processor 1601 may store instructions, which may be computer programs. The computer programs run on the processor 1601, and may enable the communication device 1600 to perform the method steps performed by the terminal 100 in the above method embodiment. The computer program may be fixed in the processor 1601, in which case the processor 1601 may be implemented by hardware.

[0393] 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.

[0394] The embodiment of the present application also provides a computer program product. When the computer program product is run on a computer, the computer executes the method in any of the aforementioned embodiments.

[0395] 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.

[0396] The embodiment of the present application also 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.

[0397] The entire application introduces the short message communication function in the Beidou communication system. It is understandable that other satellite systems may also have communication functions that support short messages. Therefore, it is not limited to the Beidou communication system. If other satellite systems also support the short message communication function, the method introduced in this application is also applicable to the communication of other satellite systems.

[0398] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned 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.

[0399] 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 (the stated condition or event) is detected" may be interpreted to mean "if determining..." or "in response to determining..." or "upon detecting (the stated condition or event)" or "in response to detecting (the stated condition or event)", depending on the context.

[0400] 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 devices. 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 a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. 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 contains one or more available media integration. 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), etc.

[0401] Those skilled in the art can understand that to implement all or part of the processes in the above-mentioned embodiments, the processes can be completed by computer programs to instruct related hardware, and the programs can be stored in computer-readable storage media. When the programs are executed, they can include the processes of the above-mentioned method embodiments. The aforementioned storage media include: ROM or random access memory RAM, magnetic disk or optical disk and other media that can store program codes.

Claims

1. A data transmission control method in a Beidou communication system, characterized in that: include: After the terminal adds padding data and a redundant length indication field to the first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer, the first message data convergence layer service data unit MDCP SDU is divided into M data convergence layer service protocol data units MDCP PDU, where M is a positive integer; wherein the redundant length indication field is used to indicate the data length of the padding data, the M 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 the order of the first MDCP PDU in the M MDCP PDUs; The terminal sends the M MDCP PDUs to a Beidou network device.

2. The method according to claim 1, characterized in that The successor indication field of the first MDCP PDU includes a first value, a second value or a third value, wherein the first value is used to indicate that the first MDCP PDU is the first MDCP PDU among the M MDCP PDUs; The second value is used to indicate that the first MDCP PDU is a middle MDCP PDU among the M MDCP PDUs; The third value is used to indicate that the first MDCP PDU is the last MDCP PDU among the M MDCP PDUs.

3. The method according to any one of claims 1 or 2, characterized in that: The successor indication field of the first MDCP PDU is a fourth value, where the fourth value is used to indicate that the first MDCP PDU is a single MDCP PDU, and M is 1.

4. The method according to any one of claims 1 to 3, characterized in that: The terminal adds padding data and redundant length indication fields to the first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer, and divides the first message data convergence layer service data unit MDCP SDU into M data convergence layer service protocol data units MDCP PDU, specifically including: The terminal generates an application layer message at the application layer; The terminal uses the application layer message as the first MDCP SDU at the MDCP layer, and divides the first MDCP SDU into the M MDCP PDUs after adding padding data and a redundant length indication field.

5. The method according to claim 4, characterized in that The terminal uses the application layer message as the first MDCP SDU at the MDCP layer, and before dividing the first MDCP SDU into the M MDCP PDUs after adding padding data and a redundant length indication field. The method further includes: The terminal obtains original data; The terminal compresses the original data at the application layer to obtain compressed data; The terminal encrypts the compressed data at the application layer to obtain encrypted data; The terminal 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.

6. The method according to any one of claims 1 to 5, characterized in that: The terminal sends the first MDCP PDU to the Beidou network device, specifically including: The terminal transmits the first MDCP PDU to the satellite link control SLC layer as a first satellite link control layer service data unit SLC SDU of the SLC layer; The terminal divides the first SLC SDU into N satellite link control layer protocol data units SLCPDU at the SLC layer, where N is a positive integer; wherein the N SLC PDUs include a first SLC PDU, and the frame header information of the first SLC PDU includes a service data unit alternation indication SAI field, a total number of frames field, and a frame sequence number field; the SAI field is used to indicate whether the first SLC PDU is retransmission data, the total number of frames field is used to indicate the total number N of SLC PDUs included in the first SLC SDU, and the frame sequence number field is used to indicate the frame sequence number of the first SLC PDU in the first SLC SDU; The terminal sends the first SLC PDU to the Beidou network device.

7. The method according to claim 6, characterized in that The terminal sends the first SLC PDU to the Beidou network device, specifically including: The terminal sends the first SLC PDU from the SLC layer to the physical PHY layer as a first coding block of the PHY layer; The terminal adds check bit information at the end of the first coding block at the PHY layer, and encodes the first coding block and the check bit information to obtain first coded data; The terminal inserts pilot information into the first coded data at the PHY layer to obtain first pilot data; The terminal modulates the first pilot data and the synchronization header of the first pilot data at the PHY layer to obtain first modulated data and a first modulated synchronization header; The terminal performs spectrum spreading on the first modulated data and the modulation synchronization header at the PHY layer to obtain first spread spectrum modulated data; The terminal sends the first spread spectrum modulated data as a first physical frame to the Beidou network device at the PHY layer.

8. The method according to claim 7, characterized in that The method further comprises: The terminal determines a data length of the first MDCP PDU according to a data length of the first MDCP SDU and a data length of the first physical frame.

9. A data transmission control method in a Beidou communication system, characterized in that: include: The Beidou network device receives M data convergence layer service protocol data units MDCP PDUs sent by the terminal, where M is a positive integer; wherein the M 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 the order of the first MDCP PDU in the M MDCP PDUs; The Beidou network device splices the M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer.

10. The method according to claim 9, characterized in that The successor indication field of the first MDCP PDU includes a first value, a second value or a third value, wherein the first value is used to indicate that the first MDCP PDU is the first MDCP PDU among the M MDCP PDUs; The second value is used to indicate that the first MDCP PDU is a middle MDCP PDU among the M MDCP PDUs; The third value is used to indicate that the first MDCP PDU is the last MDCP PDU among the M MDCP PDUs.

11. The method according to claim 9 or 10, characterized in that: The successor indication field of the first MDCP PDU is a fourth value, where the fourth value is used to indicate that the first MDCP PDU is a single MDCP PDU, and M is 1.

12. The method according to any one of claims 9 to 11, characterized in that: The Beidou network device splices the M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer, including: When the second MDCP PDU received by the Beidou network device subsequently indicates that the second MDCP PDU is the last one of the M MDCP PDUs, the Beidou network device splices the M MDCP PDUs into a first MDCP SDU at the MDCP layer, and reports the first MDCP SDU as an application layer message from the MDCP layer to the application layer.

13. The method according to claim 12, 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 Beidou network device 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 the compressed data; The Beidou network device 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.

14. The method according to any one of claims 9 to 13, characterized in that: The method further comprises: The Beidou network device splices the N SLC PDUs into the first SLC SDU at the SLC layer, and reports the first SLC SDU as the first MDCP PDU from the SLC layer of the Beidou network device to the MDCP layer of the Beidou network device; wherein the N SLC PDUs include a first SLC PDU, and the frame header information of the first SLC PDU includes a service data unit alternating indication SAI field, a total number of frames field, and a frame sequence number field; the SAI field is used to indicate whether the first SLC PDU is retransmission data, the total number of frames field is used to indicate the total number N of SLC PDUs included in the first SLC SDU, and the frame sequence number field is used to indicate the frame sequence number of the first SLC PDU in the first SLC SDU.

15. The method according to claim 14, characterized in that Before the Beidou network device splices the N SLC PDUs into the first SLC SDU at the SLC layer, and reports the first SLC SDU as the first MDCP PDU from the SLC layer of the Beidou network device to the MDCP layer of the Beidou network device, the method further includes: The Beidou network device obtains, at the PHY layer, first spread spectrum modulated data sent by the terminal; The Beidou network device despreads the first spread spectrum modulated data at the PHY layer to obtain first modulated data and a first modulation synchronization header; The Beidou network device 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 Beidou network device 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 and first verification information; The Beidou network device verifies the first coding block based on the first verification information at the PHY layer, and after the verification is successful, presents the first coding block from the PHY layer to the SLC layer of the Beidou network device as the first SLC PDU in the first SLC SDU in the SLC layer of the Beidou network device.

16. The method according to any one of claims 9 to 15, characterized in that: The Beidou network device splices the M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer, including: After removing the successor indication field of each MDCP PDU in the M MDCP PDUs at the MDCP layer, the Beidou network device splices the M MDCP PDUs into a first MDCP SDU in an order indicated by the successor indication of each MDCP PDU in the M MDCP PDUs.

17. A data transmission control method in a Beidou communication system, characterized in that: include: The Beidou network device divides the first message data convergence layer service data unit MDCP SDU into M data convergence layer service protocol data units MDCP PDU at the message data convergence MDCP layer, where M is a positive integer; wherein the M 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 the order of the first MDCP PDU in the M MDCP PDUs; The Beidou network device sends the M MDCP PDUs.

18. The method according to claim 17, characterized in that The successor indication field of the first MDCP PDU includes a first value, a second value or a third value, wherein the first value is used to indicate that the first MDCP PDU is the first MDCP PDU among the M MDCP PDUs; The second value is used to indicate that the first MDCP PDU is a middle MDCP PDU among the M MDCP PDUs; The third value is used to indicate that the first MDCP PDU is the last MDCP PDU among the M MDCP PDUs.

19. The method according to any one of claims 17 or 18, characterized in that: The successor indication field of the first MDCP PDU is a fourth value, where the fourth value is used to indicate that the first MDCP PDU is a single MDCP PDU, and M is 1.

20. The method according to any one of claims 17 to 19, characterized in that: The Beidou network device divides the first message data convergence layer service data unit MDCP SDU into M data convergence layer service protocol data units MDCP PDU at the message data convergence MDCP layer, specifically including: The Beidou network device generates an application layer message at the application layer; The Beidou network device uses the application layer message as a first MDCP SDU at the MDCP layer, and divides the first MDCP SDU into M MDCP PDUs.

21. The method according to claim 20, characterized in that The Beidou network device generates an application layer message at the application layer, specifically including: The Beidou network device obtains raw 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 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.

22. The method according to any one of claims 17 to 21, characterized in that: The Beidou network device sends the first MDCP PDU, specifically including: The Beidou network device transmits the first MDCP PDU to the satellite link control SLC layer as a first satellite link control layer service data unit SLC SDU of the SLC layer; The Beidou network device divides the first SLC SDU into N satellite link control layer protocol data units SLC PDUs at the SLC layer, where N is a positive integer; wherein the N SLC PDUs include a first SLC PDU, and the frame header information of the first SLC PDU 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, and the first frame type field is used to indicate a frame type of the first user frame; The Beidou network device sends the first SLC PDU.

23. The method according to claim 22, characterized in that The N SLC PDUs also include a second SLC PDU, and the Beidou network device sends the first SLC PDU to the terminal, including: The Beidou network device sends the first SLC PDU and the second SLC PDU to the physical PHY layer; The Beidou 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 Beidou network device sends the first physical frame and the second physical frame.

24. The method according to claim 23, characterized in that The Beidou network device sends the first physical frame and the second physical frame, including: The Beidou network device adds first check bit information at the end of the first physical frame at the PHY layer, encodes the first physical frame and the first check bit information to obtain first coded data, adds second check bit information at the end of the second physical frame, and encodes the second physical frame and the second check bit information to obtain second 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, and modulates the second coded data and the second reserved field of the second coded data to obtain second modulated data; The Beidou network device performs spectrum spreading on the first modulated data at the PHY layer to obtain first spread spectrum modulated data, and performs spectrum spreading on the second modulated data to obtain second spread spectrum modulated data; The Beidou network device sends the first spread spectrum modulation data and the first pilot information of the first spread spectrum modulation data, and the second spread spectrum modulation data and the second pilot information of the second spread spectrum modulation data at the PHY layer.

25. The method according to any one of claims 17 to 24, characterized in that: The method further comprises: The Beidou network device determines the data length of the first MDCP PDU according to the data length of the first MDCP SDU and the data length of the first physical frame.

26. A data transmission control method in a Beidou communication system, characterized in that: include: The terminal receives M data convergence layer service protocol data units MDCP PDU sent by the Beidou network device, where M is a positive integer; The M MDCP PDUs include a first MDCP PDU, and the header information of the first MDCP PDU includes a successor indication field, where the successor indication field is used to indicate the order of the first MDCP PDU in the M MDCP PDUs; The terminal splices the M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer.

27. The method according to claim 26, characterized in that The successor indication field of the first MDCP PDU includes a first value, a second value or a third value, wherein the first value is used to indicate that the first MDCP PDU is the first MDCP PDU among the M MDCP PDUs; The second value is used to indicate that the first MDCP PDU is a middle MDCP PDU among the M MDCP PDUs; The third value is used to indicate that the first MDCP PDU is the last MDCP PDU among the M MDCP PDUs.

28. The method according to claim 26 or 27, characterized in that The successor indication field of the first MDCP PDU is a fourth value, where the fourth value is used to indicate that the first MDCP PDU is a single MDCP PDU, and M is 1.

29. The method according to any one of claims 26 to 28, characterized in that: The terminal splices the M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer, including: When the second MDCP PDU received by the terminal subsequently indicates that the second MDCP PDU is the last one of the M MDCP PDUs, the terminal splices the M MDCP PDUs into a first MDCP SDU at the MDCP layer, and reports the first MDCP SDU from the MDCP layer to the application layer as an application layer message.

30. The method according to claim 29, 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 terminal decrypts the encrypted data in the application layer message at the application layer by using the encryption algorithm indicated by the encryption indication field in the application layer message to obtain the compressed data; The terminal decompresses the compressed data at the application layer by using a compression algorithm indicated by a compression indication field in the application layer message to obtain the original data.

31. The method according to any one of claims 26 to 30, characterized in that: The method further comprises: The Beidou network device splices the N SLC PDUs into the first SLC SDU at the SLC layer, and reports the first SLC SDU as the first MDCP PDU from the SLC layer of the Beidou network device to the MDCP layer of the Beidou network device; wherein the N SLC PDUs include a first SLC PDU, and the frame header information of the first SLC PDU 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, and the first frame type field is used to indicate a frame type of the first user frame.

32. The method according to claim 31, characterized in that Before the terminal splices the N SLC PDUs into the first SLC SDU at the SLC layer, and reports the first SLC SDU as the first MDCP PDU from the SLC layer of the Beidou network device to the MDCP layer of the Beidou network device, the method further includes: The terminal obtains, at the PHY layer, first spread spectrum modulated data sent by the terminal; The terminal despreads the first spread spectrum modulated data at the PHY layer to obtain first modulated data and a first modulation synchronization header; The 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 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 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 identical to the terminal ID as the first SLC PDU in the first SLC SDU in the SLC layer of the terminal from the PHY layer to the SLC layer of the terminal.

33. The method according to any one of claims 26 to 32, characterized in that: The terminal splices the M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer, including: After removing the successor indication field of each MDCP PDU in the M MDCP PDUs at the MDCP layer, the terminal splices the M MDCP PDUs into a first MDCP SDU in an order indicated by the successor indication field of each MDCP PDU in the M MDCP PDUs.

34. A Beidou communication system, characterized in that: It comprises a Beidou network device and a terminal; wherein: the terminal is used to execute a data transmission control method in a Beidou communication system as described in any one of claims 1-8 and / or claims 26-33; the Beidou network device is used to execute a data transmission control method in a Beidou communication system as described in any one of claims 9-16 and / or claims 17-25.

35. A communication device, characterized in that: It includes one or more processors, one or more memories and a transceiver; wherein the transceiver, the one or more memories are coupled to the one or more processors, the one or more memories are used to store computer program codes, and the computer program codes include computer instructions. When one or more processors execute the computer instructions, the communication device executes a data transmission control method in a Beidou communication system as described in any one of claims 9-16 and / or claims 17-25.

36. The communication device according to claim 35, characterized in that The communication device is Beidou network equipment.

37. A communication device, characterized in that: It includes one or more processors, one or more memories, and a transceiver; wherein the transceiver, the one or more memories are coupled to the one or more processors, the one or more memories are used to store computer program codes, and the computer program codes include computer instructions. When one or more processors execute the computer instructions, the communication device executes a data transmission control method in a Beidou communication system as described in any one of claims 1-8 and / or claims 26-33.

38. The communication device according to claim 37, characterized in that: The communication device is a terminal.

39. 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 executes a data transmission control method in a Beidou communication system as described in any one of claims 9-16 and / or claims 17-25.

40. 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 executes a data transmission control method in a Beidou communication system as described in any one of claims 1-8 and / or claims 26-33.

41. A chip or a chip system, applied to a terminal, characterized in that: It includes 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 a data transmission control method in a Beidou communication system as described in any one of claims 1-8 and / or claims 26-33.

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