A data transmission control method, system and related device in a Beidou communication system

Abstract

A data transmission control method, system and related device in a Beidou communication system. In the method, a terminal can split one MDCP SDU at an MDCP layer into one or more MDCP segment data of fixed length, add a subsequent indication field in the header of each MDCP segment data to obtain an MDCP PDU, and the subsequent indication field can be used to indicate that the current MDCP PDU is a starting frame or an intermediate frame or a last frame in a continuously transmitted frame, or a separately transmitted frame. The terminal can transmit one or more MDCP PDUs to a Beidou network device. The Beidou network device can combine multiple MDCP PDUs into one MDCP SDU according to the subsequent indication field in the MDCP PDU. By implementing the method, the terminal can reliably transmit data to the Beidou network device under the constraints of the Beidou communication system and the limited rate.

Description

[0001] This application is a divisional application, the original application number is 202110877288.0, the original application date is July 31, 2021, and the entire contents of the original application are incorporated herein by reference. TECHNICAL FIELD

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

[0003] The Beidou satellite navigation system is a major infrastructure integrating 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 American GPS, the Russian GLONASS and the European GALILEO. The Beidou short message communication service is particularly suitable for communication in areas such as the ocean, desert, grassland and uninhabited areas where mobile communication is not covered, or cannot be covered, or the communication system is destroyed. The short message system of the Beidou-3 satellite upgrades the short message technology system, and needs to design a communication protocol according to the characteristics of the Beidou short message system in view of the characteristics of civil service and equipment.

[0004] Since the communication system of the Beidou short message service communicates through a satellite link, its main characteristics are: 1. Long delay; 2. Large link loss; 3. The supported service is mainly a burst short message service; 4. Does not support link state management, mobility management and broadcast control information, etc. The current wireless communication protocol cannot be applied to the communication system of the Beidou short message service, because the satellite communication has a long propagation distance, and the Beidou short message service communication system has high requirements for terminal transmission power. Moreover, the limitation of the radio frequency capability of civil terminals results in a much lower inbound rate than that of dedicated terminals. Therefore, a specific data transmission process needs to be designed to reduce signaling overhead and reduce invalid transmission under the constraints of the Beidou communication system and the limited rate, so as to achieve reliable and orderly data transmission. SUMMARY

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

[0006] In a first aspect, the application provides a data transmission control method in a Beidou communication system, which can include: a terminal adding, at a message data convergence (MDCP) layer, a first MDCP service data unit (SDU) to padding data and a redundancy length indication field, and then dividing the first MDCP SDU into M data convergence layer protocol data units (MDCP PDUs), where M is a positive integer; the redundancy 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 first MDCP PDU includes a successor indication field in the header information, which is used to indicate the order of the first MDCP PDU in the M MDCP PDUs; and the terminal sends the first MDCP PDU to a Beidou network device.

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

[0008] In a 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 in the 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 an intermediate MDCP PDU in 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 in the M MDCP PDUs.

[0009] In a possible implementation, M is 1, 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 single 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 the limited rate. The header information of the MDCP PDU includes a successor indication field, which is used to indicate the order of the first MDCP PDU in the M MDCP PDUs, and a device receiving the MDCP PDU can know whether the received MDCP PDU is incorrect according to the successor indication field. In this way, signaling overhead can be reduced and invalid transmission can be reduced.

[0011] In a possible implementation, the terminal adds the first message data convergence layer service data unit (MDCP SDU) to padding data and a redundancy length indication field at a message data convergence (MDCP) layer, and divides the MDCP SDU into M data convergence layer protocol data units (MDCP PDUs), specifically including: the terminal generates an application layer message at an application layer; the terminal takes the application layer message as the first MDCP SDU at the MDCP layer, and divides the first MDCP SDU into M MDCP PDUs after adding padding data and a redundancy length indication field to the first MDCP SDU.

[0012] In a possible implementation, before the terminal takes the application layer message as the first MDCP SDU at the MDCP layer and divides the first MDCP SDU into M MDCP PDUs after adding padding data and a redundancy length indication field to the first MDCP SDU, the method further includes: the terminal obtains original data; the terminal compresses the original data to obtain compressed data at the application layer; the terminal encrypts the compressed data to obtain encrypted data at the application layer; and the terminal adds message header information to a header of the encrypted data 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 a compression algorithm used when the original data is compressed, and the encryption indication field is used to indicate an encryption algorithm used when the compressed data is encrypted.

[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 a 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 (SLC PDUs) at the SLC layer, N being a positive integer; wherein the N SLC PDUs include the first SLC PDU, and 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 a total number N of SLC PDUs included in the first SLC SDU, and the frame sequence number field is used to indicate a frame sequence number of the first SLC PDU in the first SLC SDU; and the terminal sends the first SLC PDU to the Beidou network device.

[0014] In this way, whether the value of the SAI field of the SLC PDU is flipped or not is used to indicate whether the SLC PDU is retransmission data, which can ensure that the Beidou network device identifies whether the received SLC PDU is retransmission data, and ensures 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 comprising: the terminal sends the first SLC PDU from the SLC layer to the physical (PHY) layer as a first encoding block of the PHY layer; the terminal adds check bit information at the tail of the first encoding block at the PHY layer, and encodes the first encoding block and the check bit information to obtain first encoding data; the terminal inserts pilot information in the first encoding data at the PHY layer to obtain first pilot data; the terminal modulates the first pilot data and a synchronization header of the first pilot data at the PHY layer to obtain first modulation data and a first modulation synchronization header; the terminal spreads the first modulation data and the modulation synchronization header at the PHY layer to obtain first spread modulation data; and the terminal sends the first spread modulation data as a first physical frame to the Beidou network device at the PHY layer.

[0016] In a possible implementation, 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 can include: a Beidou network device receiving M data convergence layer protocol data units (MDCP PDUs) sent by a terminal, M being 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; and the Beidou network device concatenates the M MDCP PDUs into a first message data convergence layer service data unit (MDCP SDU) at a message data convergence (MDCP) layer.

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

[0020] In a 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 in the 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 an intermediate MDCP PDU in the M MDCP PDUs; and 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 in the M MDCP PDUs.

[0021] In a possible implementation, M is 1, and the next 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 single MDCP PDU.

[0022] In this way, the Beidou network device can accurately splice the multiple MDCP PDUs into the MDCP SDU according to the order of the MDCP PDU in the multiple MDCP PDUs indicated by the next 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 aggregation layer service data unit MDCP SDU at a message data aggregation MDCP layer, including: when the Beidou network device receives the second MDCP PDU, and the next indication in the second MDCP PDU 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 the 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 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 a compression algorithm used by the terminal when the terminal compresses the original data into compressed data, and the encryption indication field is used to indicate an encryption algorithm used by the terminal when the terminal encrypts the compressed data into the encrypted data; the method further includes: the Beidou network device decrypts the encrypted data in the application layer message by using the encryption algorithm indicated by the encryption indication field in the application layer message, to obtain the compressed data; and the Beidou network device decompresses the compressed data by using the compression algorithm indicated by the compression indication field in the application layer message, to obtain the original data.

[0025] In a possible implementation, the method further includes: the Beidou network device splices N SLC PDUs into a first SLC SDU at an 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 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 a total number N of SLC PDUs included in the first SLC SDU, and the frame sequence number field is used to indicate a frame sequence number of the first SLC PDU in the first SLC SDU.

[0026] In a possible implementation, before the Beidou network device concatenates the 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 further includes: obtaining, by the Beidou network device, first spread spectrum modulation data sent by the terminal at the PHY layer; performing, by the Beidou network device, despreading on the first spread spectrum modulation data at the PHY layer to obtain first modulation data and a first modulation synchronization header; performing, by the Beidou network device, demodulation on the first modulation data and the first modulation synchronization header at the PHY layer to obtain first pilot data and a first synchronization header; removing, by the Beidou network device, pilot information in the first pilot data at the PHY layer to obtain first encoded data; performing, by the Beidou network device, decoding on the first encoded data at the PHY layer to obtain a first encoded block and first check information; performing, by the Beidou network device, check on the first encoded block based on the first check information at the PHY layer, and presenting, by the Beidou network device, the first encoded block as a first SLC PDU in the first SLC SDU of the SLC layer of the Beidou network device from the PHY layer to the SLC layer of the Beidou network device after the check succeeds.

[0027] In a possible implementation, the Beidou network device concatenates M MDCP PDUs into a first message data aggregation layer service data unit MDCP SDU at the message data aggregation MDCP layer, including: removing, by the Beidou network device, a successor indication field of each MDCP PDU in the M MDCP PDUs, and concatenating, by the Beidou network device, the M MDCP PDUs into the first MDCP SDU according to an order indicated by the successor indication field 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, which can include: dividing, by a Beidou network device, a first message data aggregation layer service data unit MDCP SDU into M data aggregation layer protocol data units MDCP PDUs at a message data aggregation MDCP layer, M being a positive integer; wherein the M MDCP PDUs include a first MDCP PDU, and header information of the first MDCP PDU includes a successor indication field, the successor indication field being used to indicate an order of the first MDCP PDU in the M MDCP PDUs; and sending, by the Beidou network device, the first MDCP PDU.

[0029] In this way, under the constraint of the Beidou communication system and the limited rate, data can be reliably transmitted between the Beidou network device and the terminal.

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

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

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

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

[0034] In a possible implementation, the Beidou network device generates an application layer message at the application layer, and specifically includes: the Beidou network device acquires original data; the Beidou network device compresses the original data to obtain compressed data at the application layer; the Beidou network device encrypts the compressed data to obtain encrypted data at the application layer; and the Beidou network device adds message header information to the header of the encrypted data 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 a compression algorithm used when the original data is compressed, and the encryption indication field is used to indicate an encryption algorithm used when the compressed data is encrypted.

[0035] In a possible implementation, the Beidou network device sends the first MDCP PDU, and specifically includes: the Beidou network device transmits the first MDCP PDU to the satellite link control (SLC) layer as a first SLC service data unit (SDU); the Beidou network device divides the first SLC SDU into N SLC PDUs at the SLC layer, where N is a positive integer; 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; and the Beidou network device sends the first SLC PDU.

[0036] In a possible implementation, the Beidou network device sends the first physical frame and the second physical frame, and specifically includes: the Beidou network device adds first check bit information at the tail of the first physical frame at the PHY layer, encodes the first physical frame and the first check bit information to obtain first encoded data, adds second check bit information at the tail of the second physical frame, and encodes the second physical frame and the second check bit information to obtain second encoded data; the Beidou network device modulates the first encoded data and a first reserved field of the first encoded data to obtain first modulation data at the PHY layer, and modulates the second encoded data and a second reserved field of the second encoded data to obtain second modulation data; the Beidou network device spreads the first modulation data to obtain first spread modulation data at the PHY layer, and spreads the second modulation data to obtain second spread modulation data; and the Beidou network device sends the first spread modulation data and first pilot information of the first spread modulation data, and the second spread modulation data and second pilot information of the second spread modulation data at the PHY layer.

[0037] In a possible implementation, 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 for a Beidou communication system is provided. The method can include: receiving, by a terminal, M data convergence protocol data units (MDCP PDUs) sent by a Beidou network device, where M is a positive integer; the M MDCP PDUs include a first MDCP PDU, and the first MDCP PDU includes a next indication field in a header, the next indication field indicating an order of the first MDCP PDU in the M MDCP PDUs; and splicing, by the terminal, the M MDCP PDUs into a first message convergence protocol service data unit (MDCP SDU) at a message convergence layer.

[0040] In this way, data can be reliably transmitted between the Beidou network device and the terminal under the constraint of the Beidou communication system and a limited rate.

[0041] In one possible implementation, M is greater than 1, the next indication field of the first MDCP PDU is a first value, and the first value indicates that the first MDCP PDU is a first MDCP PDU in the M MDCP PDUs; M is greater than 1, the next indication field of the first MDCP PDU is a second value, and the second value indicates that the first MDCP PDU is a middle MDCP PDU in the M MDCP PDUs; M is greater than 1, the next indication field of the first MDCP PDU is a third value, and the third value indicates that the first MDCP PDU is a last MDCP PDU in the M MDCP PDUs.

[0042] In one possible implementation, M is 1, the next indication field of the first MDCP PDU is a fourth value, and the fourth value indicates that the first MDCP PDU is a single MDCP PDU.

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

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

[0045] 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 a compression algorithm used by the terminal when compressing original data into compressed data, and the encryption indication field is used to indicate an encryption algorithm used by the terminal when encrypting the compressed data into the encrypted data; the method further includes: decrypting, by the terminal at the application layer, the encrypted data in the application layer message by using the encryption algorithm indicated by the encryption indication field in the application layer message, to obtain the compressed data; and decompressing, by the terminal at the application layer, the compressed data by using 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 can further include: the Beidou network device concatenating N SLC PDUs into a first SLC SDU at the SLC layer, and reporting 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 concatenates 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 can further include: obtaining, by the terminal at the PHY layer, first spread spectrum modulation data sent by the terminal; performing, by the terminal at the PHY layer, despreading on the first spread spectrum modulation data, to obtain first modulation data and a first modulation synchronization header; performing, by the terminal at the PHY layer, demodulation on the first modulation data and the first modulation synchronization header, to obtain first pilot data and a first synchronization header; removing, by the terminal at the PHY layer, pilot information in the first pilot data, to obtain first encoded data; performing, by the Beidou network device at the PHY layer, decoding on the first encoded data, to obtain a first encoded block physical frame and first check information; performing, by the terminal at the PHY layer, checking on the first encoded block based on the first check information, and after the checking succeeds, presenting, by the terminal, a first user frame with an ID field same as a terminal ID in the first encoded block as a first SLC PDU in the first SLC SDU in the SLC layer from the PHY layer to the SLC layer of the terminal.

[0048] In a possible implementation, the terminal splices the M MDCP PDUs into a first message data convergence protocol (MDCP) service data unit (SDU) at an MDCP layer, including: the terminal splices the M MDCP PDUs into the first MDCP SDU according to an order indicated by a subsequent indication field of each of the M MDCP PDUs after removing the subsequent indication field of each of the M MDCP PDUs.

[0049] In a fifth aspect, a Beidou communication system is provided, which can include a Beidou network device and a terminal; the terminal can be configured to perform the method in any possible implementation of the first aspect and the fourth aspect; and the Beidou network device can be configured to perform the method in any possible implementation of the second aspect and the third aspect.

[0050] In a sixth aspect, the present application provides a communication apparatus, including 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 configured to store computer program codes including computer instructions, which, when executed by the one or more processors, cause the communication apparatus to perform the method in any possible implementation of the first aspect and the fourth aspect.

[0051] The communication apparatus can be a terminal or a device in other product forms.

[0052] In a seventh aspect, the present application provides a communication apparatus, including 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 configured to store computer program codes including computer instructions, which, when executed by the one or more processors, cause the communication apparatus to perform the method in any possible implementation of the second aspect and the third aspect.

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

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

[0055] In a ninth aspect, the present application provides a computer storage medium, including computer instructions, which, when executed on a computer, cause the computer to perform the method in any possible implementation of the first aspect and the fourth aspect.

[0056] In a tenth aspect, the present application provides a computer program product, which, when running on a computer, causes the computer to perform the method in any possible implementation of the second aspect and the third aspect.

[0057] In an eleventh aspect, the present application provides a computer program product, which, when running on a computer, causes the computer to perform the method in any possible implementation of the first aspect and the fourth aspect.

[0058] In a twelfth aspect, the present application provides a chip or a chip system, applied to a terminal, comprising a processing circuit and an interface circuit, the interface circuit is configured to receive code instructions and transmit to the processing circuit, and the processing circuit is configured to run the code instructions to perform the method in any possible implementation of the first aspect and the fourth aspect. BRIEF DESCRIPTION OF DRAWINGS

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

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

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

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

[0063] Figure 5 is a schematic diagram of a scenario of successful transmission of multiple MDCP PDUs provided by an embodiment of the present application;

[0064] Figure 6 is a schematic diagram of a scenario of successful transmission of a single MDCP PDU provided by an embodiment of the present application;

[0065] Figure 7 is a schematic diagram of a scenario of failed transmission of multiple MDCP PDUs provided by an embodiment of the present application;

[0066] Figure 8 is a schematic diagram of a scenario of failed transmission of multiple MDCP PDUs provided by an embodiment of the present application;

[0067] Figure 9 is a schematic diagram of a scenario of successful transmission of multiple MDCP PDUs provided by an embodiment of the present application;

[0068] Figure 10 FIG. 10 is a schematic diagram of a protocol processing flow of data by a Beidou communication system 10 at an MDCP layer and an SLC layer according to an embodiment of the present application;

[0069] Figure 11A FIG. 11 is a schematic diagram of a protocol encapsulation architecture of outbound data of a Beidou communication system 10 according to an embodiment of the present application;

[0070] Figure 11B FIG. 12 is a schematic diagram of a protocol parsing architecture of outbound data of a Beidou communication system 10 according to an embodiment of the present application;

[0071] Figure 11C FIG. 13 is a schematic diagram of a data transmission control method in a Beidou communication system according to an embodiment of the present application;

[0072] Figure 11D FIG. 14 is a schematic diagram of a data transmission control method in a Beidou communication system according to an embodiment of the present application;

[0073] Figure 12 FIG. 15 is a schematic diagram of a structure of a terminal 100 according to an embodiment of the present application;

[0074] Figure 13 FIG. 16 is a schematic diagram of a structure of a communication apparatus according to an embodiment of the present application;

[0075] Figure 14 FIG. 17 is a schematic diagram of a structure of another communication apparatus according to an embodiment of the present application;

[0076] Figure 15 FIG. 18 is a schematic diagram of a structure of another communication apparatus according to an embodiment of the present application;

[0077] Figure 16 FIG. 19 is a schematic diagram of a structure of another communication apparatus according to an embodiment of the present application. DETAILED DESCRIPTION

[0078] The terminology used in the following description of the embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the description of the embodiments and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It also will be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0079] The terms "first", "second", "third", etc. are used only for the purpose of description, and cannot be understood as implying or suggesting relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features, and in the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0080] A Beidou communication system 10 provided in an embodiment of the present application is introduced below.

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

[0082] As shown above Figure 1 The Beidou communication system 10 can 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 can also include a national emergency rescue platform 26 and a national emergency rescue center 27.

[0083] The terminal 100 can send short message information to the Beidou short message satellite 21, which 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 a 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 a short message to the short message center 25 through a traditional cellular communication network. The short message center 25 can forward the short message of the terminal 300 to the Beidou network device 200. The Beidou network device 200 can relay the short message of the terminal 300 to the terminal 100 through the Beidou short message satellite 21.

[0085] The Beidou network device 200 can include a Beidou ground transceiver station 22, a Beidou center station 23, and a Beidou short message integrated communication platform 24. The Beidou ground transceiver station 22 can include one or more devices with a sending function and one or more devices with a receiving function, or can include one or more devices with both a sending function and a receiving function, which is not limited here. The Beidou ground transceiver station 22 can be used for the processing function of the Beidou network device 200 on data in the physical layer (physical layer protocol, PHY). The Beidou center station 23 can be used for the processing function of the Beidou network device 200 on data in the satellite link layer (satellite link control protocol, SLC) layer and the message convergence layer (message data convergence protocol, MDCP). The Beidou short message integrated communication platform 24 can be used for the processing function of data in the application layer (application layer protocol, APP).

[0086] The Beidou communication system 10 communicates through a satellite link, and its main characteristics are long time delay (about 270 ms in one direction) and large link loss. The current Beidou communication system 10 supports mainly the burst short message service, and does not support link state management, mobility management, and broadcast control information, etc.

[0087] The terminal 100 can actively send data to the Beidou network device 200 through the Beidou short message satellite 21. However, since there is no air interface signaling, the ground center station cannot actively page the user. Due to the long propagation distance of satellite communication, the transmission power requirement for the terminal 100 in the Beidou communication system 10 is high. Limited by the current terminal 100 radio frequency device, 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 terminal 100 radio frequency device, the terminal 100 radio frequency device must stop working for a period of time before it can continue to switch to the sending state to continue working. The duration of the sending state of the terminal 100 is determined by the bottom hardware capability 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 by the terminal 100 do not interfere with each other, the terminal 100 does not support the simultaneous occurrence of sending data and receiving data. The terminal 100 needs to wait for the data sent by the Beidou network device 200 after sending data.

[0088] The working mode of the Beidou network device 200 can be a duplex mode, which can simultaneously send and receive data, and the Beidou network device 200 can send and receive data for a long time.

[0089] The general consumer's usage habits can send more data at a time. When the data is more, the terminal needs to send multiple frames of data, so the sending time will be longer. In order to avoid invalid sending, a separate layer of protocol is needed to manage multiple frames of data sent by the user, and therefore, a message convergence layer (MDCP) is defined. The MDCP layer can receive the application layer data passed down from the application layer, and send the processed data packet to the lower layer satellite link control layer (SLC).

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

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

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

[0093] Figure 2 A transmission process diagram of data inbound in a Beidou communication system is shown.

[0094] As Figure 2As shown, data inbound can refer to terminal 100 sending data to beidou network device 200. For example, terminal 100 can send a data frame to beidou ground transceiver station 22. Beidou ground transceiver station 22 can send the data frame to beidou center station 23. Beidou center station 23 can aggregate the data frame into a data message and report it to beidou short message integrated communication platform 24. Beidou center station 23 can return an acknowledge character (ACK) of SLC layer to terminal 100 after receiving the data frame sent by terminal 100. The ACK can be used to indicate whether beidou network device 200 successfully receives the data frame sent by terminal 100.

[0095] The protocol encapsulation architecture of inbound data of beidou communication system 10 provided in the embodiments of the present application is introduced below.

[0096] Figure 3 The protocol encapsulation architecture of inbound data of beidou communication system 10 provided in the embodiments of the present application is introduced below.

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

[0098] When terminal 100 sends data to beidou network device 200, the working process of beidou message transmission protocol on terminal 100 can be as follows:

[0099] At APP layer, terminal 100 can compress original data into compressed data through compression algorithm, and add 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. Then, terminal 100 can encrypt the compressed data to obtain encrypted data, and add encryption algorithm field in the header of the encrypted data, which is used to indicate the encryption algorithm type of the encrypted data. Terminal 100 can encapsulate the encrypted data, compression indication field and encryption indication field into application layer message and send it to MDCP layer. The application layer message includes message header and message data. The message header includes compression indication field, encryption indication field and the like. The message data includes the above encrypted data.

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

[0101] At the MDCP layer, the terminal 100 can obtain the application layer packet issued by the APP layer through the interlayer interface, and take the application layer packet as an MDCP SDU. At the MDCP layer, the terminal 100 can add padding data to a specified length at the tail of the MDCP SDU, and add a redundant length indication field at 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 adding the padding data and the redundant length indication field into one or more MDCP segment data (M_segement) of a fixed length, and add a subsequent indication field at the head of each M_segement to obtain an MDCP PDU, that is, the MDCP PDU includes the M_segement and the subsequent indication field. The subsequent indication field can be used to indicate that the current MDCP PDU is a starting MDCP PDU or an intermediate MDCP PDU or a last MDCP PDU of a plurality of MDCP PDUs sent continuously, or is a single MDCP PDU sent alone.

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

[0103] The SAI field can 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 can 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 the SLC PDU belongs.

[0106] At the PHY layer, the terminal 100 can obtain the SLC PDU issued by the SLC layer through the interlayer interface as a code block of the PHY layer, and add a synchronization header in the header of the code block and a check bit field in the tail of the code block. In the above Beidou communication system 10, the code block can be checked by cyclic redundancy check (CRC), so the check bit field can include a CRC code. The terminal 100 can encode (for example, polar encoding) the code block and the check bit field to obtain coded data, and then insert a pilot in the coded data to obtain pilot+data. Then, the terminal 100 modulates the synchronization header and the pilot+data in sequence through the underlying hardware to obtain modulated data. The terminal 100 can spread the modulated data to obtain spread+modulated data. The terminal 100 can send the spread+modulated data to the Beidou short message satellite 21, which relays and forwards the spread+modulated data to the Beidou network device 200.

[0107] The protocol analysis architecture of the inbound data of the Beidou communication system 10 provided in the embodiments of the present application is introduced below.

[0108] Figure 4 The protocol analysis architecture of the inbound data of the Beidou communication system 10 provided in the embodiments of the present application is introduced below.

[0109] As shown in Figure 4 , the Beidou short message transmission protocol layer of the Beidou network device 200 can be divided into an application layer (application layer protocol), a message convergence layer (message data convergence protocol, MDCP), a satellite link layer (satellite link control protocol, SLC), and a physical layer (physical layer protocol, PHY). The Beidou network device 200 can include a Beidou ground transceiver station 22, a Beidou center station 23, and a Beidou short message converged 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 center station 23 can be used to be responsible for the protocol processing of the SLC layer and the MDCP layer. The Beidou short message converged 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 workflow of the Beidou short message transmission protocol layer of the Beidou network device 200 can be as follows:

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

[0113] At the MDCP layer, the Beidou network device 200 can splice 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 interlayer 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 protocol processing process is only an example for illustration, and the specific operation of the protocol processing is not limited in the present application.

[0116] Next, the fields involved in the MDCP SDU and the MDCP PDU in the MDCP layer will be specifically introduced.

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

[0118] The redundancy length indication field is used to indicate the length of padding in the MDCP SDU. In a possible implementation, the redundancy length indication field has a length of 8 bits. It can be understood that the length of the redundancy length indication field is not limited in the embodiments of the present application.

[0119] 2. The successor indication field in the MDCP PDU

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

[0121] Table 1

[0122] Subsequent indication Explanation 00 PDU of a single MDCP 01 First PDU of a plurality of MDCP PDUs 11 Intermediate PDU of a plurality of MDCP PDUs 10 Last PDU of a plurality of 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 in a plurality of MDCP PDUs; when the successor indication field is "11", it indicates that the MDCP PDU is an intermediate PDU in a plurality of MDCP PDUs; and when the successor indication field is "10", it indicates that the MDCP PDU is the last PDU in a plurality of MDCP PDUs.

[0124] It can be understood that the value of the successor indication field and the corresponding meaning shown in Table 1 are only examples. The length of the successor indication field, the specific bit value of the successor indication field, and the meaning corresponding to the bit value are not limited in the embodiments of the present application.

[0125] The design of the successor indication field is shown below based on Table 1, and 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 are introduced respectively.

[0126] 1. The transmission scenario of the 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, i.e., when the length of the successor indication field is 2 bits, the value of the successor indication field does not contain "00" and the corresponding meaning. The value of the successor indication field contains "01", "10", and "11".

[0128] When an MDCP PDU is the first MDCP PDU among multiple MDCP PDUs, its successor indicator field can be "01". When an MDCP PDU is the middle MDCP PDU among multiple MDCP PDUs, its successor indicator field can be "11". When an MDCP PDU is a single MDCP PDU, or the last MDCPPDU among multiple MDCP PDUs, its successor indicator field can be "10".

[0129] Scenario 1: Multiple MDCP PDUs successfully transmitted

[0130] Figure 5 An example is shown where multiple MDCP PDUs are successfully transmitted when the subsequent indication field does not contain a 00 field.

[0131] like Figure 5 As shown, terminal 100 can send four MDCP PDUs to BeiDou network device 200. Of these four MDCP PDUs, the one with a successor indication field of "01" is the first MDCP PDU, the one with a successor indication field of "11" is the middle MDCP PDU, and the one with a successor indication field of "10" is the last PDU. During the normal transmission of these four MDCP PDUs, BeiDou network device 200 can successfully receive all four MDCP PDUs.

[0132] It is understandable that after terminal 100 sends an MDCP PDU to BeiDou network device 200, terminal 100 will only send a new MDCP PDU after receiving an ACK from BeiDou network device 200 in response to the SLC SDU corresponding to the MDCP PDU.

[0133] Scenario 2: Successful transmission of a single MDCP PDU

[0134] Figure 6 An example is shown where a single MDCP PDU is successfully transmitted when there is no 00 field in the subsequent indication field.

[0135] like Figure 6 As shown, terminal 100 can send a single MDCP PDU to BeiDou network device 200. The follow-up indication field of this MDCP PDU is "10". BeiDou network device 200 can successfully receive this single MDCP PDU.

[0136] Scenario 3: The last MDCP PDU among multiple MDCP PDUs was not received, and the wait timed out.

[0137] Figure 7 The scenario of the transmission failure of multiple MDCP PDUs when there is no 00 field in the successor indication field is exemplarily shown.

[0138] As shown in Figure 7 The terminal 100 can send four MDCP PDUs to the Beidou network device 200. Among the four 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 intermediate MDCP PDU, and the MDCP PDU with the successor indication field of "10" is the last PDU packet. The Beidou network device 200 does not receive the last MDCP PDU among the four MDCP PDUs sent by the terminal 100. The Beidou network device 200 waits for timeout, the terminal 100 fails to transmit, and the current transmission is normally ended.

[0139] In the case that the Beidou network device waits for timeout at the MDCP layer, that is, the Beidou network device waits for timeout at the SLC layer to receive the SLC SDU. For example, one SLC SDU includes N SLC PDUs, and the maximum time for the terminal to receive each SLC PDU is a first time length. If the Beidou network device still does not receive the next MDCP PDU after receiving one MDCP PDU at the MDCP layer and the interval is a second time length, it can be called that the Beidou network device waits for timeout at the MDCP layer. The second time length can be N first time lengths.

[0140] Scenario 4: The last MDCP PDU among multiple MDCP PDUs is not received, and the waiting is not timeout

[0141] Figure 8 The scenario of the transmission failure of multiple MDCP PDUs when there is no 00 field in the successor indication field is exemplarily shown.

[0142] As shown in 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 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 does not receive the last MDCP PDU among the 4 MDCP PDUs sent by the terminal 100. The Beidou network device 200 waits without timeout, and the terminal 100 initiates a new service, i.e., sends a new MDCP PDU, which is a single MDCP PDU, and the successor indication field of the single MDCP PDU is "10". For example, when the terminal sends the MDCP PDU, an exception occurs, the terminal is forced to restart, and then the user initiates a service on the terminal again. At this time, the Beidou network device 200 can regard the single MDCP PDU as the last MDCP PDU among the 4 MDCP PDUs sent by the terminal 100 before. Then, the Beidou network device 200 combines the single MDCP PDU and the 3 MDCP PDUs received last time into one MDCP SDU. In this way, the Beidou network device 200 recombines the MDCP SDU packet incorrectly.

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

[0144] The value of the successor indication field includes "00", "01", "10", and "11". The corresponding meanings of the values of the successor indication field can be referred to the description in Table 1 above.

[0145] Scenario 5: Last PDU among multiple MDCP PDUs is not received, and waiting without timeout

[0146] Figure 9 Exemplarily, the scenario of multiple MDCP PDU transmission failure when there is no "00" in the successor indication field is shown.

[0147] As Figure 9As shown, terminal 100 can send four MDCP PDUs to BeiDou network device 200. Of these four MDCP PDUs, the one with a successor indication field of "01" is the first MDCP PDU, the one with a successor indication field of "11" is the middle MDCP PDU, and the one with a successor indication field of "10" is the last PDU. BeiDou network device 200 does not receive the last MDCP PDU sent by terminal 100. Before the timeout period, terminal 100 sends another separate MDCP PDU with a successor indication field of "00". BeiDou network device 200 can determine that this MDCP PDU is a separate MDCPPDU based on the "00" successor indication field. Therefore, BeiDou network device 200 will not reassemble this separate MDCP PDU with the previously received MDCP PDU into an MDCP SDU. This means that the Beidou network equipment 200 will not experience packet misassembly issues.

[0148] The following section details the protocol processing flow of data in the MDCP and SLC layers of the BeiDou communication system 10.

[0149] Figure 10 This paper illustrates a schematic diagram of the protocol processing flow of the BeiDou communication system 10 at the MDCP layer and SLC layer in an embodiment of this application.

[0150] 1. Protocol encapsulation process of transmitted data at the MDCP layer by terminal 100

[0151] like Figure 10 As shown, at the MDCP layer, terminal 100 can split the padded data and the MDCP SDU with the added redundant length indicator field into one or more fixed-length MDCP segment data (M_segement), and add a successor indicator field to the header of each MDCP segment data to obtain an MDCP PDU. That is, the MDCP PDU includes M_segement and a successor indicator field. Terminal 100 can store the split MDCP PDUs into the MDCP layer transmit buffer (MDCP Tx buffer) in a first-in-first-out order. The data length of the successor indicator field can occupy 2 bits. The meaning of the value of the successor indicator field can be shown in Table 1 above.

[0152] For example, the terminal 100 can split the padding data and the MDCP SDU with the added redundancy length indication field into 3 MDCP PDUs, in which the 3 MDCP PDUs are MDCP PDU0, MDCP PDU1 and MDCP PDU2 in order from high bit to low bit. Since MDCP PDU0 is the starting MDCP PDU in the current MDCP SDU, the terminal 100 can set the value of the next indication field in MDCP PDU0 to "01". Since MDCP PDU1 is the middle MDCP PDU in the current MDCP SDU, the terminal 100 can set the value of the next indication field in MDCP PDU1 to "11". MDCP PDU2 is the last MDCP PDU in the current MDCP SDU, and the terminal 100 can set the value of the next indication field in MDCP PDU2 to "10".

[0153] For another example, the terminal 100 can split the padding data and the MDCP SDU with the added redundancy length indication field into 2 MDCP PDUs, in which the 2 MDCP PDUs are MDCP PDU0 and MDCP PDU1 in order from high bit to low bit. Since MDCP PDU0 is the starting MDCP PDU in the current MDCP SDU, the terminal 100 can set the value of the next indication field in MDCP PDU0 to "01". Since MDCP PDU1 is the last MDCP PDU in the current MDCP SDU, the terminal 100 can set the value of the next indication field in MDCP PDU1 to "10".

[0154] For another example, the terminal 100 can split the padding data and the MDCP SDU with the added redundancy length indication field into 2 MDCP PDUs, in which the 2 MDCP PDUs are MDCP PDU0 and MDCP PDU1 in order from high bit to low bit. Since MDCP PDU0 is the starting MDCP PDU in the current MDCP SDU, the terminal 100 can set the value of the next indication field in MDCP PDU0 to "01". Since MDCP PDU1 is the last MDCP PDU in the current MDCP SDU, the terminal 100 can set the value of the next indication field in MDCP PDU1 to "10".

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

[0156] 2. Protocol encapsulation process of terminal 100 on SLC layer for sending data.

[0157] On SLC layer, terminal 100 can control the SLC PDU sending strategy of SLC layer, including initial transmission and retransmission of SLC PDU, based on the receiving feedback (e.g. ACK) sent by Beidou network device 200 through SLC layer sending state controller. Terminal 100 can obtain the MDCP PDU sent by MDCP layer as SLC SDU through interlayer interface. When terminal 100 sends a previous SLC SDU to Beidou network device 200 and confirms that Beidou network device 200 receives successfully, terminal 100 can obtain the next MDCP PDU from MDCP layer as the next SLC SDU and send it to Beidou network device 200.

[0158] Optionally, in a possible implementation, terminal 100 splits MDCP SDU into multiple MDCP PDUs on MDCP layer, and terminal 100 can transmit the multiple MDCP PDUs to SLC layer of terminal 100 together.

[0159] For example, terminal 100 can split the padding data and MDCP SDU after adding the redundancy length indication field into 3 MDCP PDUs. In order, the 3 MDCP PDUs are MDCP PDU0, MDCP PDU1 and MDCP PDU2 from high bit to low bit. On SLC layer, terminal 100 first obtains MDCP PDU0 sent by MDCP layer through interlayer interface, and terminal 100 can send MDCP PDU0 as the first SLC SDU of this message transmission process to Beidou network device 200. After terminal 100 determines that the data of the first SLC SDU has been sent to Beidou network device 200, terminal 100 can obtain MDCP PDU1 from MDCP layer and send MDCP PDU1 as the second SLC SDU of this message transmission process to Beidou network device 200. After terminal 100 determines that the data of the second SLC SDU has been sent to Beidou network device 200, terminal 100 can obtain MDCP PDU2 from MDCP layer and send MDCP PDU2 as the last SLC SDU of this message transmission process to Beidou network device 200.

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

[0161] In 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 in the header of each S_segement to obtain an SLC PDU. The frame header information includes SAI field, frame total number field and frame sequence number field. Wherein:

[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 yes, 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 in the SLC PDU in the previous SLC SDU session (including the initial transmission session of the SLC SDU or the retransmission session of the SLC SDU); 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 in 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 in the SLC PDU in the previous SLC SDU session, it indicates that the SLC PDU is retransmission data.

[0163] It can be understood 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 Beidou network device 200 receives the SAI field of the first SLC SDU that 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 numerical values, and the application does not limit the preset initial value of the SAI field.

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

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

[0166] (2) Frame total number field, which can be used to represent the total number of SLC PDUs included in the SLC SDU to which the SLC PDU belongs. When one SLC SDU in the Beidou communication system 10 can be divided into at most 4 SLC segment data (S_segment) of fixed length, the frame total number field can occupy 2 bits.

[0167] For example, when the SLC SDU includes only one SLC PDU, the value of the frame total number field of the only one SLC PDU in the SLC SDU can be "00". When the SLC SDU includes two SLC PDUs, the values of the frame total number 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 frame total number fields of the three SLC PDUs in the SLC SDU can all be "10". When the SLC SDU includes four SLC PDUs, the values of the frame total number 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) Frame sequence number field, which can be used to represent the sequence number of the SLC PDU in the SLC SDU to which the SLC PDU belongs. When one SLC SDU in the Beidou communication system 10 can be divided into at most 4 SLC segment data (S_segment) of fixed length, the frame sequence number field can occupy 2 bits.

[0170] For example, when only one SLC PDU is included in the SLC SDU, the value of the frame sequence number field of the only one SLC PDU in the SLC SDU can be "00". When two SLC PDUs are included in the SLC SDU, the value of the frame sequence number field of the first SLC PDU in the SLC SDU can be "00", and the value of the frame sequence number field of the second SLC PDU in the SLC SDU can be "01". When three SLC PDUs are included in the SLC SDU, the value of the frame sequence number field of the first SLC PDU in the SLC SDU can be "00", the value of the frame sequence number field of the second SLC PDU in the SLC SDU can be "01", and the value of the frame sequence number field of the third SLC PDU in the SLC SDU can be "10". When four SLC PDUs are included in the SLC SDU, the value of the frame sequence number field of the first SLC PDU in the SLC SDU can be "00", the value of the frame sequence number field of the second SLC PDU in the SLC SDU can be "01", the value of the frame sequence number field of the third SLC PDU in the SLC SDU can be "10", and the value of the frame sequence number field of 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 parses the protocol of the 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 SLC PDUs in a SLC SDU have been received based on the frame header information of the SLC PDU. If yes, the Beidou network device 200 can sequentially splice one or more received SLC PDUs into a SLC SDU according to the values of the frame sequence number fields from small to large. If not, after the receiving window at the SLC layer ends, the Beidou network device 200 can send feedback information (for example, ACK) to notify the terminal 100 to retransmit the un-received SLC PDU. After splicing the SLC SDU, the Beidou network device 200 can report the SLC SDU to the MDCP layer as an MDCP PDU through the interlayer interface.

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

[0175] For example, the SAI value of the first SLC PDU in the first SLC SDU received by the Beidou network device 200 can be "0", the frame total value can be "11", and the frame sequence number can be "00". The SAI value of the second SLC PDU in the first SLC SDU can be "0", the frame total value can be "11", and the frame sequence number can be "01". The SAI value of the third SLC PDU in the first SLC SDU can be "0", the frame total value can be "11", and the frame sequence number can be "10". The SAI value of the fourth SLC PDU in the first SLC SDU can be "0", the frame total value can be "11", and the frame sequence number can be "11". The Beidou network device 200 can splice the four SLC PDUs in the order of the frame sequence number from small to large into the first SLC SDU, and report the first SLC SDU to the MDCP layer as the MDCP PDU0 of the MDCP layer. The Beidou network device 200 can store the MDCP PDU0 in the MDCP layer receiving buffer (MDCP Rxbuffer). The value of the successor indication field in the 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 can be "1", the frame total value can be "11", and the frame sequence number can be "00". The SAI value of the second SLC PDU in the second SLC SDU can be "1", the frame total value can be "11", and the frame sequence number can be "01". The SAI value of the third SLC PDU in the second SLC SDU can be "1", the frame total value can be "11", and the frame sequence number can be "10". The SAI value of the fourth SLC PDU in the second SLC SDU can be "1", the frame total value can be "11", and the frame sequence number can be "11". The Beidou network device 200 can splice the four SLC PDUs in the order of the frame sequence number from small to large into the second SLC SDU, and report the second SLC SDU to the MDCP layer as the MDCP PDU1 of the MDCP layer. The Beidou network device 200 can store the MDCP PDU1 in the MDCP layer receiving buffer (MDCP Rxbuffer). The value of the successor 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 can be "0", the frame total value can be "11", and the frame sequence number can be "00". The SAI value of the second SLC PDU in the third SLC SDU can be "0", the frame total value can be "11", and the frame sequence number can be "01". The SAI value of the third SLC PDU in the third SLC SDU can be "0", the frame total value can be "11", and the frame sequence number can be "10". The SAI value of the fourth SLC PDU in the third SLC SDU can be "0", the frame total value can be "11", and the frame sequence number can be "11". The Beidou network device 200 can splice the four SLC PDUs in ascending order of the frame sequence number to form the third SLC SDU, and report the third SLC SDU to the MDCP layer as an MDCP PDU2 of the MDCP layer. The Beidou network device 200 can store the MDCP PDU2 in the MDCP layer receiving buffer (MDCP Rx buffer). The value of the next 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. Protocol analysis process of the Beidou network device 200 on the MDCP layer for received data.

[0180] At the MDCP layer, the Beidou network device 200 can aggregate multiple MDCP PDUs in the order of receiving time based on the next indication field in the MDCP PDU after receiving all MDCP PDUs of one MDCP SDU sent by the terminal 100, to obtain the MDCP SDU.

[0181] When the Beidou network device 200 obtains the MDCP PDU with the value of the next indication field being "11" from the SLC layer, the Beidou network device 200 can take out all MDCP PDUs from the MDCP Rx buffer, splice them according to the value of the next 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 interlayer interface as an application layer message.

[0182] The following describes the segmentation processing flow of the MDCP SDU at the MDCP layer when inbound.

[0183] The following describes an example in which the terminal 100 segments one MDCP SDU into one or more MDCP PDUs. The terminal 100 can segment one MDCP SDU into one or more MDCP PDUs, including the following steps:

[0184] 1. The data application compression and encryption of the application layer of the terminal 100, 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 a MDCP SDU according to the transmission capability provided by the SLC layer, and the data part of each MDCP PDU obtained by segmenting the MDCP SDU and the padding data; here, the transmission capability of the SLC layer is obtained from the PHY layer through the interlayer transmission interface. The transmission capability of the SLC layer refers to the 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 segments the MDCP SDU into multiple MDCP PDUs by adding padding data and a redundancy length indication field according to the number of segments SegmentNumOfMsdu and the sequence number of the MDCP PDU, wherein the redundancy length indication field is used to indicate the data length of the padding data. Then the terminal 100 determines the successor indication of each MDCP PDU, and finally forms a complete MDCP PDU; wherein the successor indication needs to indicate the first MDCP PDU, the intermediate MDCP PDU, and the last MDCP PDU in the multiple MDCP PDUs; if the current SegmentNumOfMsdu = 1, the successor indication needs to indicate that the current MDCP PDU is a separate MDCP PDU; if SegmentNumOfMsdu = 4, the successor indication needs 4 states, 2 bits;

[0187] 4. The terminal 100 delivers the MDCP PDU to the SLC layer through the interlayer interface as the SLC SDU of the SLC layer.

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

[0189] In the following, taking the Beidou network device 200 reassembling one or more MDCP PDUs received into a MDCP SDU as an example. The Beidou network device 200 reassembling one or more MDCP PDUs into a MDCP SDU can include the following steps:

[0190] 1、In SLC layer, the Beidou network device 200 can calculate the length of a MDCP PDU data packet according to the frame number and the total number of frames carried by the received SLC PDU of SLC layer and the frame length of a SLC PDU blindly decoded. The Beidou network device 200 reports the calculated length of a MDCP PDU data packet to MDCP layer.

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

[0192] Then, the Beidou network device 200 can obtain the length of the packet after grouping according to the length of each MDCP PDU. By analyzing the bits of the redundancy length indication, the length of the padding bit is obtained, so that the padding bit can be removed to obtain the MDCP SDU data.

[0193] 2、In MDCP layer, the Beidou network device 200 combines one or more MDCP PDUs received 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 takes the single MDCP PDU as a MDCP SDU data packet.

[0195] If the subsequent indication field of the current MDCP PDU indicates that the current MDCP PDU is not the first MDCP PDU in the plurality of MDCP PDUs, nor a single MDCP PDU (i.e. the last MDCP PDU or an intermediate MDCP PDU in the plurality of MDCP PDUs), the Beidou network device 200 groups the current received MDCP PDU after removing the subsequent indication field with the previously received MDCP PDU after removing the subsequent indication field in order. Until the subsequent indication field of the received MDCP PDU indicates that the current MDCP PDU is the last MDCP PDU, the Beidou network device 200 groups the last MDCP PDU after removing the subsequent indication field with the previously grouped data to obtain the MDCP SDU data packet.

[0196] 3. The Beidou network equipment 200 transmits the MDCP SDU to the application layer for processing (such as decryption and decompression).

[0197] Understandably, since terminals can retransmit upon inbound communication, for example, during a transmission, terminal 100 might send SLC PDU0 to BeiDou network device 200 and then retransmit the same SLC PDU0. BeiDou network device 200 needs to determine if the received SLC PDU is a retransmission; if so, it discards the retransmitted SLC PDU at the SLC layer. After receiving all MDCP PDUs from the MDCP layer, BeiDou network device 200 assembles them into MDCP SDU packets, parses the redundancy length indicator field from the MDCP SDU, removes the padding data, and then passes it to the application layer for subsequent decryption and decompression operations.

[0198] Table 2 illustrates, for example, the reconstruction of a single MDCP PDU into an MDCP SDU.

[0199] Table 2

[0200]

[0201] As shown in Table 2, taking the BeiDou Network 200 device as an example, it combines a single MDCP PDU into an MDCP SDU. The BeiDou Network 200 device can then use encoded data (i.e....) Figure 3 The length of the MDCP PDU packet is calculated from the length of the codedata shown in Table 2. Then, based on the length of the MDCP PDU, the length of the MDCP SDU can be obtained. As shown in Table 2, taking a 512-bit encoded data (including codeblocks and parity bits) as an example, the length of a PDU in the SLC layer is also the length of a codeblock, which is the length of the encoded data minus the length of the parity bits (512 bits - 24 bits), resulting in 488 bits. The frame header in the SLCPDU is 64 bits long, so the length of the S_segment in 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 successor indicator and M_segment), the length of the MDCP PDU is reduced by the length of the successor indicator (2 bits), the length of the redundancy length indicator (8 bits), and the length of the MDCP SDU (assuming it is 177 bits) to obtain the padding (237 bits).

[0202] It can be understood that Table 2 is only an example and does not limit the embodiments of the present application.

[0203] Table 3 exemplarily shows an MDCP SDU being divided into multiple MDCP PDUs.

[0204] Table 3

[0205]

[0206] As shown in Table 3, the terminal 100 divides one MDCP SDU into two MDCP PDUs as an example. As shown in Table 3, the terminal 100 receives a data packet at the MDCP layer as an MDCP SDU, and the data length of the MDCP SDU is 2106 bits. The terminal 100 obtains the data length of coded data (i.e., codedata shown in Table 3) from the physical layer, and the data length of the coded data is 512 bits, and the length of the check bit is 24 bits. Therefore, the terminal 100 can determine the transmission capability provided by the SLC layer, that is, the data length of one SLC PDU that can be transmitted by the SLC layer, which is the data length of the coded data (i.e., codedata shown in Table 3) minus the length of the check bit and the length of the SLC PDU header, that is, 424 bits. Then, the terminal 100 can determine the number of segments of the MDCP SDU according to the data length of one SLC PDU, that is, the MDCP SDU can be divided into two MDCP PDUs, and 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). Figure 3 Figure 3 It can be understood that Table 3 is only an example and does not limit the embodiments of the present application.

[0207] It can be understood that Table 3 is only an example and does not limit the embodiments of the present application.

[0208] The protocol encapsulation architecture of the outbound data of the Beidou communication system 10 provided in the embodiments of the present application is introduced as follows.

[0209] Figure 11A The protocol encapsulation architecture of the outbound data of the Beidou communication system 10 provided in the embodiments of the present application is introduced as follows.

[0210] As Figure 11A ​As shown, the Beidou short message transmission protocol layer in the Beidou network device 200 can include an application layer, a message data convergence protocol (MDCP) layer, a satellite link control protocol (SLC) layer, and a physical layer. The Beidou network device 200 can include a Beidou ground transceiver station 22, a Beidou center station 23, and a Beidou short message fusion communication platform 24. The Beidou ground transceiver station 22 can be configured to perform protocol processing for the PHY layer. The Beidou center station 23 can be configured to perform protocol processing for the SLC layer and the MDCP layer. The Beidou short message fusion communication platform 24 can be configured to perform protocol processing for the APP layer.

[0211] When the Beidou network device 200 transmits data to the terminal 100, the working process of the Beidou short message transmission protocol in the Beidou network device 200 can be as follows:

[0212] 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. The compression indication field can be used to indicate the compression algorithm type of the compressed data. Then, the Beidou network device 200 can encrypt the compressed data to obtain encrypted data, and add an encryption algorithm field in the header of the encrypted data. 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. The application layer message can include a message header and message data. The message header can include the compression indication field, the encryption indication field, and the like. The message data includes the encrypted data.

[0213] Optionally, in a possible implementation, the Beidou network device 200 divides the MDCP SDU into multiple MDCP PDUs at the MDCP layer, and the Beidou network device 200 can transmit the multiple MDCP PDUs to the SLC layer of the Beidou network device 200.

[0214] At the MDCP layer, the Beidou network device 200 can obtain the application layer message issued by the APP layer through the interlayer interface, and take the application layer message as an MDCP SDU. At the MDCP layer, the Beidou network device 200 can split one MDCP SDU into one or more MDCP segment data (M_segement) of fixed length, and add a subsequent indication field in the header of each MDCP segment data to obtain an MDCP PDU, that is, the MDCP PDU includes the M_segement and the subsequent indication field. The subsequent indication field can be used to indicate that the current MDCP PDU is a starting MDCP PDU or an intermediate MDCP PDU or a last MDCP PDU of the continuously transmitted multiple MDCP PDUs, or is a single transmitted MDCP PDU.

[0215] At the SLC layer, the Beidou network device 200 can obtain the MDCP PDU issued by the MDCP layer through the interlayer interface as an SLC SDU. At the SLC layer, the Beidou network device 200 can segment the SLC SDU into one or more (up to 4) SLC segment data (S_segement) of fixed length, and add frame header information in the header of each S_segement to obtain an SLC PDU.

[0216] At the PHY layer, the Beidou network device 200 can obtain the SLC PDU issued by the SLC layer through the interlayer interface. The Beidou network device 200 can obtain the SLC PDU of one user or multiple users from the SLC layer. The Beidou network device 200 can splice the SLC PDUs of multiple users together, and then add the frame header (such as version number) of the physical frame as a code block of the PHY layer, and add a check bit (such as a cyclic redundancy check (CRC) code) in the tail of the code block, and encode the code block and the CRC code (such as polar encoding), and the encoded physical frame plus the reserved segment can constitute the encoded data of an electric text branch (S2C_d branch) of a physical time slot of fixed length. The Beidou network device 200 can put multiple SLC PDUs of one user into different physical frames. Then, the Beidou network device 200 groups the encoded data of the S2C_d branch and the pilot information of a pilot branch (S2C_p branch) into pilot encoded data, that is, outbound data. The Beidou network device 200 can send the outbound data to the Beidou short message satellite 21, which relays and forwards the outbound data to the terminal 100 via the Beidou short message satellite 21.

[0217] It can be understood that the pilot information of the S2C_p branch is related to the satellite beam. When the satellite beam number is known information, the pilot information of the S2C_p branch is also known information, and does not need to be decoded. The encoded data of the S2C_d branch needs to be decoded.

[0218] The protocol analysis architecture of the outbound data of the Beidou communication system 10 provided in the embodiment of the application is introduced below.

[0219] Figure 11B The protocol analysis architecture of the outbound data of the Beidou communication system 10 provided in the embodiment of the application is introduced below.

[0220] As shown in Figure 11B The Beidou short message transmission protocol layer of the terminal 100 can be divided into an application layer, a message data convergence layer (MDCP), a satellite link control layer (SLC) and a physical layer (PHY).

[0221] When the terminal 100 receives the data sent by the Beidou network device, the working process of the Beidou short message transmission protocol layer of the terminal 100 can be as follows:

[0222] At the PHY layer, the terminal 100 can obtain the pilot encoded data sent by the Beidou network device 200 after modulation and spreading. The terminal 100 can despread the received spread+modulated data to obtain modulated data. Then, the terminal 100 can demodulate the modulated data to obtain pilot+data. Next, the terminal 100 can remove the pilot information in the pilot+data to obtain code data. Then, the terminal 100 can decode the code data and verify the integrity of the code block through the check data in the check bit field. If it is complete, the terminal 100 can extract the code block and present it to the SLC layer through the interlayer interface as the SLC PDU of the SLC layer.

[0223] Here, the pilot encoded data is the outbound data sent by the Beidou network device 200 described above, and the outbound data is composed of the encoded data of the S2C_d branch and the pilot information of the pilot branch (S2C_p branch).

[0224] 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 interlayer interface as an MDCP PDU of the MDCP layer.

[0225] At the MDCP layer, the terminal 100 can splice all the MDCP PDUs belonging to the same MDCP SDU into one MDCP SDU. The terminal 100 can present the MDCP SDU to the APP layer through the interlayer interface as an application layer message received by the APP layer.

[0226] At the APP layer, the terminal 100 can decrypt and decompress the application layer message based on the message header of the application layer message to obtain the original data.

[0227] In the embodiments of the present application, the above protocol processing process is only an example for illustration, and the specific operation of the protocol processing is not limited in the present application.

[0228] The following describes the segmentation processing procedure of the MDCP SDU of the MDCP layer when outbound.

[0229] The following describes an example in which the Beidou network device 200 segments one MDCP SDU into one or more MDCP PDUs. The segmentation of the MDCP SDU into one or more MDCP PDUs by the Beidou network device 200 can include the following steps:

[0230] 1. The data of the application layer of the Beidou network device 200 after application compression and encryption is used as an MDCP SDU of the MDCP layer, and the data amount of the MDCP SDU can be denoted as DataSizeOfMsdu.

[0231] 2. The Beidou network device 200 can calculate the segmentation number SegmentNumOfMsdu of one MDCP SDU according to the transmission capability provided by the SLC layer, and the data part of each MDCP PDU obtained by the segmentation of the MDCP SUD;

[0232] 3. The Beidou network device 200 determines the successor indication of each MDCP PDU according to the segment number SegmentNumOfMsdu and the sequence number of the MDCP PDU, and finally forms a complete MDCP PDU; wherein the successor indication needs to indicate the first MDCP PDU, the intermediate MDCP PDU, and the last MDCP PDU in multiple MDCP PDUs; if the current SegmentNumOfMsdu = 1, the successor indication needs to indicate that the current MDCP PDU is a single MDCP PDU; if SegmentNumOfMsdu = 4, the successor indication needs 4 states, 2 bits.

[0233] 4. The Beidou network device 200 delivers the MDCP PDU to the SLC layer through the interlayer interface as an SLC SDU of the SLC layer.

[0234] Next, the reassembly processing flow of the MDCP PDU of the MDCP layer when outbound is introduced.

[0235] Hereinafter, an example in which the terminal 100 reassembles one or more MDCP PDUs received into one MDCP SDU is taken as an example for illustration. The terminal 100 reassembling one or more MDCP PDUs into one MDCP SDU can include the following steps:

[0236] 1. In the SLC layer, the terminal 100 can calculate the length of one MDCP PDU data packet according to the frame sequence number and the total number of frames carried by the received SLC PDU of the SLC layer, and the frame length of one SLC PDU. The terminal 100 reports the calculated length of one MDCP PDU data packet to the MDCP layer.

[0237] 2. In the MDCP layer, the terminal 100 combines one or more MDCP PDUs received into one complete MDCP SDU data packet according to the successor indication field of each MDCP PDU.

[0238] If the successor indication field of the MDCP PDU indicates that the MDCP PDU is a single MDCP PDU, the terminal 100 takes the single MDCP PDU as a MDCP SDU data packet.

[0239] If the successor indication bit of the current MDCP PDU indicates that the current MDCP PDU is not the first MDCP PDU in the multiple MDCP PDUs, nor is a single MDCP PDU (i.e. is the last MDCP PDU or an intermediate MDCP PDU in the multiple MDCP PDUs), the terminal 100 will package the current received MDCP PDU after removing the successor indication field and the previously received MDCP PDU after removing the successor indication field 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 will package the last MDCP PDU after removing the successor indication field and the previously packaged data, and finally obtain the MDCP SDU data packet.

[0240] 3. The terminal 100 delivers the MDCP SDU to the application layer for processing (such as decryption and decompression, etc.).

[0241] A data transmission control method in a Beidou communication system is provided in the embodiments of the present application.

[0242] Figure 11C A flowchart of the data transmission control method in the Beidou communication system is shown.

[0243] As shown in Figure 11C , the data transmission control method in the Beidou communication system can include:

[0244] S1101. The terminal 100 adds a first message data aggregation layer service data unit MDCP SDU to padding data and a redundancy length indication field in the message data aggregation MDCP layer, and divides it into M data aggregation layer protocol data units MDCP PDUs.

[0245] Wherein, M is a positive integer; the redundancy 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 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 terminal sends the first MDCP PDU to the Beidou network device.

[0246] In a possible implementation, M is greater than 1, the next indication field of the first MDCP PDU is a first value, the first value is used to indicate that the first MDCP PDU is the first MDCP PDU in the M MDCP PDUs; M is greater than 1, the next indication field of the first MDCP PDU is a second value, the second value is used to indicate that the first MDCP PDU is a middle MDCP PDU in the M MDCP PDUs; M is greater than 1, the next indication field of the first MDCP PDU is a third value, the third value is used to indicate that the first MDCP PDU is the last MDCP PDU in the M MDCP PDUs.

[0247] In a possible implementation, M is 1, the next indication field of the first MDCP PDU is a fourth value, the fourth value is used to indicate that the first MDCP PDU is a single MDCP PDU.

[0248] S1102, the terminal 100 sends the first MDCP PDU to the Beidou network device 200.

[0249] S1103, the Beidou network device 200 receives the M data convergence layer protocol data units MDCP PDUs sent by the terminal 100.

[0250] S1104, the Beidou network device 200 concatenates the M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU in a message data convergence MDCP layer.

[0251] Some possible implementations of the terminal 100 are described below.

[0252] In a possible implementation, the terminal 100 divides the first message data convergence layer service data unit MDCP SDU into M data convergence layer protocol data units MDCP PDUs after adding padding data and a redundancy length indication field in a message data convergence MDCP layer, and the method specifically comprises: the terminal 100 generates an application layer message in an application layer; and the terminal 100 divides the application layer message into M MDCP PDUs after adding padding data and a redundancy length indication field in the MDCP layer as a first MDCP SDU.

[0253] In a possible implementation, before the terminal 100 divides the first MDCP SDU into M MDCP PDUs after adding padding data and a redundancy length indication field to the first MDCP SDU at the MDCP layer, the method further includes: obtaining, by the terminal 100, original data; compressing, by the terminal 100, the original data at the application layer to obtain compressed data; encrypting, by the terminal 100, the compressed data at the application layer to obtain encrypted data; and adding, by the terminal 100, header information to a header of the encrypted data to obtain the application layer message, wherein the header information includes a compression indication field and an encryption indication field, the compression indication field is used to indicate a compression algorithm used when the original data is compressed, and the encryption indication field is used to indicate an encryption algorithm used when the compressed data is encrypted.

[0254] In a possible implementation, the terminal 100 sends the first MDCP PDU to the Beidou network device, and specifically includes: transmitting, by the terminal 100, the first MDCP PDU to a satellite link control (SLC) layer as a first SLC service data unit (SDU); dividing, by the terminal 100, the first SLC SDU into N satellite link control protocol data units (SLC PDUs) at the SLC layer, N being a positive integer; wherein the N SLC PDUs include the first SLC PDU, and 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 a total number N of SLC PDUs included in the first SLC SDU, and the frame sequence number field is used to indicate a frame sequence number of the first SLC PDU in the first SLC SDU; and sending, by the terminal 100, the first SLC PDU to the Beidou network device.

[0255] In this way, whether the value of the SAI field of the SLC PDU is flipped or not is used to indicate whether the SLC PDU is retransmission data, which can ensure that the Beidou network device identifies whether the received SLC PDU is retransmission data, and ensures continuous data transmission in the Beidou communication system.

[0256] In a possible implementation, the terminal 100 sends the first SLC PDU to the Beidou network device, specifically comprising: the terminal 100 sends the first SLC PDU from the SLC layer to the physical (PHY) layer as a first encoding block of the PHY layer; the terminal 100 adds check bit information at the tail of the first encoding block in the PHY layer, and encodes the first encoding block and the check bit information to obtain first encoding data; the terminal 100 inserts pilot information in the first encoding data in the PHY layer to obtain first pilot data; the terminal 100 modulates the first pilot data and a synchronization header of the first pilot data in the PHY layer to obtain first modulation data and a first modulation synchronization header; the terminal 100 spreads the first modulation data and the modulation synchronization header in the PHY layer to obtain first spread modulation data; and the terminal 100 sends the first spread modulation data as a first physical frame to the Beidou network device in the PHY layer.

[0257] In a possible implementation, 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.

[0258] In this way, the terminal 100 can know how to split the MDCP SDU into multiple MDCP PDUs.

[0259] Some possible implementations performed by the Beidou network device 200 are described below.

[0260] In a possible implementation, the Beidou network device 200 assembles the M MDCP PDUs into a first message data aggregation layer service data unit (MDCP SDU) in a message data aggregation MDCP layer, comprising: when the Beidou network device 200 receives the second MDCP PDU, and the subsequent indication in the second MDCP PDU indicates that the second MDCP PDU is the last one of the M MDCP PDUs, the Beidou network device 200 assembles the M MDCP PDUs into the first MDCP SDU in the MDCP layer, and reports the first MDCP SDU as an application layer packet from the MDCP layer to the application layer.

[0261] 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 a compression algorithm used by the terminal 100 when compressing the original data into compressed data, and the encryption indication field is used to indicate an encryption algorithm used by the terminal 100 when encrypting the compressed data into the encrypted data; the method further includes: the Beidou network device 200 decrypts the encrypted data in the application layer message by using the encryption algorithm indicated by the encryption indication field in the application layer message, to obtain the compressed data; and the Beidou network device 200 decompresses the compressed data by using the compression algorithm indicated by the compression indication field in the application layer message, to obtain the original data.

[0262] In a possible implementation, the method further includes: the Beidou network device 200 concatenates 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, 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.

[0263] In a possible implementation, before the Beidou network device 200 concatenates 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, the method further includes: the Beidou network device 200 acquires 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 first modulation data and a 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 first pilot data and a first synchronization header; the Beidou network device 200 removes pilot information in the first pilot data at the PHY layer, to obtain first encoded data; the Beidou network device 200 decodes the first encoded data at the PHY layer, to obtain a first encoded block and first check information; and the Beidou network device 200 checks the first encoded block based on the first check information at the PHY layer, and after the checking succeeds, submits the first encoded block as the first SLC PDU in the first SLC SDU in the SLC layer of the Beidou network device 200 from the PHY layer to the SLC layer of the Beidou network device 200.

[0264] In a possible implementation, the Beidou network device 200 splices the M MDCP PDUs into a first message data aggregation layer service data unit MDCP SDU at a message data aggregation MDCP layer, including: the Beidou network device 200 splices the M MDCP PDUs into the first MDCP SDU according to an order indicated by a subsequent indication of each of the M MDCP PDUs after removing the subsequent indication of each of the M MDCP PDUs at the MDCP layer.

[0265] Figure 11D A flowchart of a data transmission control method in a Beidou communication system is shown.

[0266] As shown in Figure 11D , the data transmission control method in the Beidou communication system can include:

[0267] S2101, the Beidou network device 200 divides a first message data aggregation layer service data unit MDCP SDU into M data aggregation layer protocol data units MDCP PDUs at a message data aggregation MDCP layer.

[0268] wherein M is a positive integer; the M MDCP PDUs include a first MDCP PDU, and the first MDCP PDU includes a subsequent indication field in the header information, and the subsequent indication field is used to indicate the order of the first MDCP PDU in the M MDCP PDUs; and the Beidou network device 200 sends the first MDCP PDU.

[0269] wherein in a possible implementation, M is greater than 1, the subsequent 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 in the M MDCP PDUs; M is greater than 1, the subsequent 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 an intermediate MDCP PDU in the M MDCP PDUs; M is greater than 1, the subsequent 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 in the M MDCP PDUs.

[0270] wherein in a possible implementation, M is 1, the subsequent 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 single MDCP PDU.

[0271] S2102, the Beidou network device 200 sends the first MDCP PDU to the terminal 100.

[0272] S2103, the terminal 100 receives the M data convergence layer protocol data units MDCP PDUs sent by the Beidou network device 200.

[0273] S2104, the terminal 100 splices the M MDCP PDUs into a first message data convergence layer service data unit MDCP SDU at the message data convergence MDCP layer.

[0274] Some possible implementation manners of the Beidou network device 200 are introduced below.

[0275] In a possible implementation manner, the Beidou network device 200 divides the first message data convergence layer service data unit MDCP SDU into M data convergence layer protocol data units MDCP PDUs 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 takes the application layer message as the first MDCP SDU at the MDCP layer, and divides the first MDCP SDU into M MDCP PDUs.

[0276] In a possible implementation manner, the Beidou network device 200 generates an application layer message at the application layer, specifically including: the Beidou network device 200 acquires original data; the Beidou network device 200 compresses the original data to obtain compressed data at the application layer; the Beidou network device 200 encrypts the compressed data to obtain encrypted data at the application layer; the Beidou network device 200 adds message header information to the header of the encrypted data 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 the original data is compressed, and the encryption indication field is used to indicate the encryption algorithm used when the compressed data is encrypted.

[0277] In a possible implementation, the Beidou network device 200 sends the first MDCP PDU, specifically comprising: the Beidou network device 200 transmits the first MDCP PDU to the satellite link control (SLC) layer as a first SLC 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 PDUs) at the SLC layer, N being a positive integer; wherein the N SLC PDUs comprise a first SLC PDU, and the frame header information of the first SLC PDU comprises a first user ID field and a first frame type field, the first user ID field being used to indicate the terminal 100 receiving the first user frame, and the first frame type field being used to indicate the frame type of the first user frame; and the Beidou network device 200 sends the first SLC PDU.

[0278] In a possible implementation, the Beidou network device 200 sends the first physical frame and the second physical frame, comprising: the Beidou network device 200 adds first check bit information at the tail of the first physical frame at the PHY layer, and encodes the first physical frame and the first check bit information to obtain first encoded data, and adds second check bit information at the tail of the second physical frame, and encodes the second physical frame and the second check bit information to obtain second encoded data; the Beidou network device 200 modulates the first encoded data and a first reserved field of the first encoded data to obtain first modulation data at the PHY layer, and modulates the second encoded data and a second reserved field of the second encoded data to obtain second modulation data; the Beidou network device 200 spreads the first modulation data to obtain first spread modulation data at the PHY layer, and spreads the second modulation data to obtain second spread modulation data; and the Beidou network device 200 sends the first spread modulation data and first pilot information of the first spread modulation data, and the second spread modulation data and second pilot information of the second spread modulation data at the PHY layer.

[0279] In a possible implementation, the method further comprises: 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.

[0280] In this way, the Beidou network device 200 can know how to split the MDCP SDU into multiple MDCP PDUs.

[0281] Some possible implementations performed by the terminal 100 are introduced below.

[0282] In a possible implementation, the terminal 100 concatenates the M MDCP PDUs into a first message data convergence protocol (MDCP) service data unit (SDU) at a message data convergence (MDCP) layer, including: when the terminal 100 receives a second MDCP PDU, and the second MDCP PDU indicates that the second MDCP PDU is the last one of the M MDCP PDUs, the terminal 100 concatenates the M MDCP PDUs into a first MDCP SDU at the MDCP layer, and reports the first MDCP SDU as an application layer packet from the MDCP layer to the application layer.

[0283] In a possible implementation, the application layer packet includes a packet header and encrypted data, the packet header includes an encryption indication field and a compression indication field, the compression indication field is used to indicate a compression algorithm used by the terminal 100 when the terminal 100 compresses original data into compressed data, and the encryption indication field is used to indicate an encryption algorithm used by the terminal 100 when the terminal 100 encrypts the compressed data into the encrypted data; the method further includes: the terminal 100 decrypts the encrypted data in the application layer packet by using the encryption algorithm indicated by the encryption indication field in the application layer packet, to obtain the compressed data; and the terminal 100 decompresses the compressed data by using the compression algorithm indicated by the compression indication field in the application layer packet, to obtain the original data.

[0284] In a possible implementation, the method can further include: the Beidou network device 200 concatenates N SLC PDUs into a first SLC SDU at an 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 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 a first user frame, and the first frame type field is used to indicate a frame type of the first user frame.

[0285] In a possible implementation, before the terminal 100 concatenates the 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, the method can further include: the terminal 100 acquires 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 first modulation data and a first modulation synchronization header; the terminal 100 demodulates the first modulation data and the first modulation synchronization header at the PHY layer to obtain first pilot data and a first synchronization header; the terminal 100 removes pilot information in the first pilot data at the PHY layer to obtain first encoding data; the Beidou network device 200 decodes the first encoding data at the PHY layer to obtain a first encoding block physical frame and first check information; and the terminal 100 checks the first encoding block based on the first check information at the PHY layer, and after the check succeeds, delivers a first user frame with an ID field same as an ID of the terminal 100 in the first SLC SDU in the SLC layer of the terminal 100 as a first SLC PDU from the PHY layer to the SLC layer of the terminal 100.

[0286] In a possible implementation, the terminal 100 concatenates M MDCP PDUs into a first message data aggregation layer service data unit MDCP SDU at the message data aggregation MDCP layer, including: the terminal 100 removes a successor indication field of each MDCP PDU in the M MDCP PDUs, and then concatenates the M MDCP PDUs into the first MDCP SDU according to an order indicated by the successor indication of each MDCP PDU in the M MDCP PDUs.

[0287] Next, an exemplary terminal 100 provided by the embodiments of the present application is introduced.

[0288] Figure 12 FIG. 1 is a structural schematic diagram of the terminal 100 provided by the embodiments of the present application.

[0289] The embodiments are specifically described below by taking the terminal 100 as an example. It should be understood that the terminal 100 can have more or fewer components than those shown in the figure, can combine two or more components, or can have a different component configuration. The various components shown in the figure can be implemented in hardware, software, or a combination of hardware and software, including one or more signal processing and / or application specific integrated circuits.

[0290] The terminal 100 can 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, a headset jack 170D, a sensor module 180, a key 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 can include a pressure sensor 180A, a gyroscope sensor 180B, a barometric 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.

[0291] It can be understood that the structure shown in the embodiments of the present application does not constitute a specific limitation on the terminal 100. In other embodiments of the present application, the terminal 100 can include more or fewer components than shown, or combine certain components, or split certain components, or different component arrangements. The components shown can be implemented in hardware, software, or a combination of software and hardware.

[0292] The processor 110 can include one or more processing units, for example: the processor 110 can include an application processor (AP), a modem processor, a graphics processing unit (GPU), an image signal processor (ISP), a controller, a memory, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural-network processing unit (NPU), etc. Different processing units can be independent devices, or can be integrated into one or more processors.

[0293] The controller can be the nerve center and command center of the terminal 100. The controller can generate operation control signals according to instruction operation codes and timing signals, and complete the control of fetching instructions and executing instructions.

[0294] The processor 110 can also include a memory that stores instructions and data. In some embodiments, the memory in the processor 110 is a cache memory. The cache memory can hold instructions or data that the processor 110 has recently used or is likely to use again. If the processor 110 needs to use the instructions or data again, it can be retrieved directly from the cache memory. This avoids repeated accesses and reduces the latency of the processor 110, thus improving the efficiency of the system.

[0295] In some embodiments, the processor 110 can include one or more interfaces. The interfaces can 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.

[0296] The I2C interface is a bidirectional synchronous serial bus that includes a serial data line (SDA) and a serial clock line (SCL). In some embodiments, the processor 110 can include multiple sets of I2C buses. The processor 110 can 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 can be coupled to the touch sensor 180K through an I2C interface, so that the processor 110 and the touch sensor 180K communicate through the I2C bus interface to realize the touch function of the terminal 100.

[0297] The I2S interface can be used for audio communication. In some embodiments, the processor 110 can include multiple sets of I2S buses. The processor 110 can be coupled to the audio module 170 through the I2S bus to realize communication between the processor 110 and the audio module 170. In some embodiments, the audio module 170 can deliver audio signals to the wireless communication module 160 through the I2S interface to realize the function of answering a phone through a Bluetooth headset.

[0298] The PCM interface can also be used for audio communication, sampling, quantizing and encoding analog signals. In some embodiments, the audio module 170 can be coupled with the wireless communication module 160 through a PCM bus interface. In some embodiments, the audio module 170 can also transmit audio signals to the wireless communication module 160 through the PCM interface, enabling the function of answering a phone call through a Bluetooth headset. Both the I2S interface and the PCM interface can be used for audio communication.

[0299] The UART interface is a universal serial bus for asynchronous communication. The bus can be a bidirectional communication bus. It converts data to be transmitted between serial communication and parallel communication. In some embodiments, the UART interface is usually 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, enabling Bluetooth functionality. In some embodiments, the audio module 170 can transmit audio signals to the wireless communication module 160 through the UART interface, enabling the function of playing music through a Bluetooth headset.

[0300] The MIPI interface can be used to connect the processor 110 and peripheral devices such as the display screen 194 and the camera 193. The MIPI interface includes the camera serial interface (CSI), the display serial interface (DSI), etc. In some embodiments, the processor 110 and the camera 193 communicate through the CSI interface, enabling the camera function of the terminal 100. The processor 110 and the display screen 194 communicate through the DSI interface, enabling the display function of the terminal 100.

[0301] The GPIO interface can be configured through 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 and the camera 193, the display screen 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.

[0302] The SIM interface can be used to communicate with the SIM card interface 195, enabling the function of transmitting data to the SIM card or reading data in the SIM card.

[0303] The USB interface 130 is an interface conforming to the USB standard specification, and 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 a peripheral device. It can also be used to connect a headset to play audio through the headset. The interface can also be used to connect other electronic devices, such as AR devices, etc.

[0304] It can be understood that the interface connection relationship between the modules shown in the embodiments of the present application is only illustrative and does not constitute a structural limitation of the terminal 100. In some other embodiments of the present application, the terminal 100 can also use different interface connection methods or a combination of multiple interface connection methods.

[0305] The charging management module 140 is used to receive charging input from a charger. The charger can be a wireless charger or a wired charger.

[0306] The power management module 141 is used to connect the battery 142 and the charging management module 140 to 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, etc.

[0307] The wireless communication function of the terminal 100 can be realized by the antenna 1, the antenna 2, the mobile communication module 150, the wireless communication module 160, the modem processor, and the baseband processor, etc.

[0308] The antenna 1 and the antenna 2 are used to transmit and receive electromagnetic wave signals. Each antenna in the terminal 100 can be used to cover a single or multiple communication frequency bands. Different antennas can also be multiplexed to improve the utilization rate of the antennas. For example, the antenna 1 can be multiplexed 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.

[0309] The mobile communication module 150 can provide a solution including 2G / 3G / 4G / 5G, etc. wireless communication applied to the terminal 100. The mobile communication module 150 can 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 by the antenna 1, and perform filtering, amplification, etc. on the received electromagnetic waves, and transfer the same to the modem processor to be demodulated. The mobile communication module 150 can also amplify the signal modulated by the modem processor, and radiate the same as electromagnetic waves through the antenna 1. In some embodiments, at least part of the function modules of the mobile communication module 150 can be provided in the processor 110. In some embodiments, at least part of the function modules of the mobile communication module 150 can be provided in the same device as at least part of the modules of the processor 110.

[0310] The modem processor can include a modulator and a demodulator. The modulator is used to modulate a low-frequency baseband signal to be transmitted into a medium-high frequency signal. The demodulator is used to demodulate a received electromagnetic wave signal into a low-frequency baseband signal. The demodulator then transfers the demodulated low-frequency baseband signal to the baseband processor for processing. The low-frequency baseband signal processed by the baseband processor is transferred to the application processor. The application processor outputs a sound signal through an audio device (not limited to the speaker 170A, the microphone 170B, etc.), or displays an image or a video through the display screen 194. In some embodiments, the modem processor can be an independent device. In other embodiments, the modem processor can be independent of the processor 110, and provided in the same device as the mobile communication module 150 or other function modules.

[0311] The wireless communication module 160 can provide a wireless communication solution applied to the terminal 100, including wireless local area networks (WLAN) (e.g., wireless fidelity (Wi-Fi) network), Bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), infrared (IR), Beidou communication, etc. The wireless communication module 160 can be one or more devices integrated with at least one communication processing module. The wireless communication module 160 receives electromagnetic waves via the antenna 2, frequency-modulates and filters the electromagnetic wave signals, and transmits the processed signals to the processor 110. The wireless communication module 160 can also receive signals to be transmitted from the processor 110, frequency-modulate them, amplify them, and radiate them as electromagnetic waves via the antenna 2.

[0312] In some embodiments, antenna 1 and mobile communication module 150 of terminal 100 are coupled, and antenna 2 and wireless communication module 160 are coupled, so that terminal 100 can communicate with a network and other devices through wireless communication technology. The wireless communication technology can 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, etc. The GNSS can include global positioning system (GPS), global navigation satellite system (GLONASS), Beidou navigation satellite system (BDS), quasi-zenith satellite system (QZSS), and / or satellite based augmentation systems (SBAS).

[0313] In some embodiments, terminal 100 can communicate with Beidou network device 200 through the Beidou communication technology. Optionally, the Beidou communication technology can exist in a separate chip, or can be integrated in wireless communication module 160.

[0314] Terminal 100 implements display functions through GPU, display screen 194, and application processor, etc. GPU is a microprocessor for image processing, connected to display screen 194 and application processor. GPU is used to perform mathematical and geometric calculations, for graphics rendering. Processor 110 can include one or more GPUs that execute program instructions to generate or change display information.

[0315] The display screen 194 is configured to display images, videos, and the like. The display screen 194 includes a display panel. The display panel can be a liquid crystal display (LCD), an organic light-emitting diode (OLED), an active-matrix organic light-emitting diode (AMOLED), a flex light-emitting diode (FLED), a Miniled, a MicroLed, a Micro-oLed, a quantum dot light emitting diodes (QLED), or the like. In some embodiments, the terminal 100 can include one or N display screens 194, where N is a positive integer greater than 1.

[0316] The terminal 100 can implement the photographing function through the ISP, the camera 193, the video codec, the GPU, the display screen 194, and the application processor.

[0317] The ISP is configured to process the data fed back by the camera 193. For example, when taking a photo, the shutter is opened, 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 the ISP for processing to convert it into an image visible to the naked eye. The ISP can also perform algorithm optimization on the noise, brightness, and color of the image. The ISP can also optimize the exposure, color temperature, and other parameters of the shooting scene. In some embodiments, the ISP can be disposed in the camera 193.

[0318] The camera 193 is configured to capture still images or videos. An object generates an optical image through a lens and projects it onto a photosensitive element. The photosensitive element can be a charge coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) phototransistor. The photosensitive element converts the light signal into an electrical signal, and then transmits the electrical signal to the ISP to convert it 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 the like format. In some embodiments, the terminal 100 can include one or N cameras 193, where N is a positive integer greater than 1.

[0319] The digital signal processor is used to process digital signals, in addition to being able to process digital image signals, it can also process other digital signals. For example, when the terminal 100 selects a frequency point, the digital signal processor is used to perform Fourier transform on the frequency point energy, etc.

[0320] The video codec is used to compress or decompress digital video. The terminal 100 can support one or more video codecs. In this way, the terminal 100 can play or record videos in multiple encoding formats, such as: moving picture experts group (MPEG) 1, MPEG 2, MPEG 3, MPEG 4, etc.

[0321] The NPU is a neural-network (NN) calculation processor, which can quickly process input information by drawing on the structure of a biological neural network, such as drawing on the transmission mode between human brain neurons, and can also constantly self-learn. Through the NPU, intelligent cognitive applications of the terminal 100 can be realized, such as: image recognition, face recognition, voice recognition, text understanding, etc.

[0322] The internal memory 121 can include one or more random access memories (RAMs) and one or more non-volatile memories (NVMs).

[0323] The random access memory can 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, such as the fifth generation DDR SDRAM commonly referred to as DDR5 SDRAM), etc.

[0324] The non-volatile memory can include magnetic disk storage devices, flash memory.

[0325] The flash memory can include NOR FLASH, NAND FLASH, 3D NAND FLASH, etc. according to the operation principle, single-level cell (SLC), multi-level cell (MLC), triple-level cell (TLC), quad-level cell (QLC), etc. according to the storage unit potential order, and universal flash storage (UFS), embedded multi media Card (eMMC), etc. according to the storage specification.

[0326] 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 an operating system or other programs running, and can also be used to store data of users and application programs, etc.

[0327] The non-volatile memory can also store executable programs and store data of users and application programs, etc., which can be loaded in advance into the random access memory for direct reading and writing by the processor 110.

[0328] The terminal 100 can realize audio functions through the audio module 170, the speaker 170A, the receiver 170B, the microphone 170C, the earphone interface 170D, and the application processor, etc. For example, music playing, recording, etc.

[0329] The audio module 170 is used to convert digital audio information into analog audio signals, 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 part of the function modules of the audio module 170 can be arranged in the processor 110.

[0330] The speaker 170A, also known as a "loudspeaker", is used to convert audio electrical signals into sound signals. The terminal 100 can listen to music or listen to a hands-free call through the speaker 170A.

[0331] The receiver 170B, also known as a "earpiece", is used to convert audio electrical signals into sound signals. When the terminal 100 answers a call or a voice message, the receiver 170B can be held close to the ear to listen to the voice.

[0332] Microphone 170C, also called "microphone", "transducer", is used to convert sound signal into electric signal. When making a call or sending voice message, user can make sound by approaching microphone 170C with mouth, inputting sound signal into microphone 170C. Terminal 100 can be provided with at least one microphone 170C. In some other embodiments, terminal 100 can be provided with two microphones 170C, which can realize noise reduction function besides sound signal collection. In some other embodiments, terminal 100 can be provided with three, four or more microphones 170C, which can realize sound signal collection, noise reduction, sound source identification, directional recording and other functions.

[0333] Earphone interface 170D is used to connect wired earphone. Earphone interface 170D can be USB interface 130, or 3.5mm open mobile terminal platform (OMTP) standard interface, or cellular telecommunications industry association of the USA (CTIA) standard interface.

[0334] Pressure sensor 180A is used to sense pressure signal, and can convert pressure signal into electric signal. In some embodiments, pressure sensor 180A can be provided on display screen 194. There are many types of pressure sensor 180A, such as resistance type pressure sensor, inductance type pressure sensor, capacitance type pressure sensor, etc. Capacitance type pressure sensor can include at least two parallel plates with conductive material. When force is applied to pressure sensor 180A, the capacitance between electrodes changes. Terminal 100 determines the intensity of pressure according to the change of capacitance. When touch operation is applied to display screen 194, terminal 100 detects the intensity of touch operation according to pressure sensor 180A. Terminal 100 can also calculate the position of touch according to the detection signal of pressure sensor 180A. In some embodiments, touch operation applied to the same touch position but with different touch operation intensity can correspond to different operation instructions. For example, when touch operation with intensity less than first pressure threshold is applied to short message application icon, the instruction of viewing short message is executed. When touch operation with intensity greater than or equal to first pressure threshold is applied to short message application icon, the instruction of creating new short message is executed.

[0335] The gyro 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 gyro sensor 180B. The gyro sensor 180B can be used for anti-shake photography. For example, when the shutter is pressed, the gyro sensor 180B detects the angle of shaking of the terminal 100, calculates the distance that the lens module needs to compensate according to the angle, and lets the lens offset the shaking of the terminal 100 by reverse movement to achieve anti-shake. The gyro sensor 180B can also be used for navigation and motion sensing game scenarios.

[0336] The barometer sensor 180C is used to measure air pressure. In some embodiments, the terminal 100 calculates the altitude, assists in positioning and navigation by using the air pressure value measured by the barometer sensor 180C.

[0337] The magnetic sensor 180D includes a Hall sensor. The terminal 100 can detect the opening and closing of a flip cover with the magnetic sensor 180D. 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. In turn, according to the detected opening and closing state of the cover or the opening and closing state of the flip cover, the terminal 100 can set features such as automatic unlocking of the flip cover.

[0338] The acceleration sensor 180E can detect the magnitude of acceleration of the terminal 100 in various directions (typically three axes). When the terminal 100 is stationary, it can detect the magnitude and direction of gravity. It can also be used to identify the posture of the electronic device and applied to landscape / portrait screen switching, pedometers, and other applications.

[0339] The distance sensor 180F is used to measure distance. The terminal 100 can measure distance by infrared or laser. In some embodiments, in a shooting scenario, the terminal 100 can use the distance sensor 180F to measure distance to achieve fast focusing.

[0340] The proximity light sensor 180G can include, for example, a light-emitting diode (LED) and a light detector, such as a photodiode. The light-emitting diode can be an infrared light-emitting diode. The terminal 100 emits infrared light outwardly through the light-emitting diode. The terminal 100 detects infrared reflected light from nearby objects using the photodiode. 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 is holding the terminal 100 close to the ear for a call, so as to automatically turn off the screen to achieve power saving. The proximity light sensor 180G can also be used for automatic unlocking and locking of the cover in cover mode and pocket mode.

[0341] Ambient light sensor 180L is used to sense ambient light brightness. Terminal 100 can adaptively adjust display screen 194 brightness according to sensed ambient light brightness. Ambient light sensor 180L can also be used to automatically adjust white balance when taking a picture. Ambient light sensor 180L can also cooperate with proximity light sensor 180G to detect whether terminal 100 is in a pocket to prevent accidental touch.

[0342] Fingerprint sensor 180H is used to collect a fingerprint. Terminal 100 can use collected fingerprint characteristics to implement fingerprint unlocking, access application lock, take a picture with fingerprint, answer a call with fingerprint, etc.

[0343] Temperature sensor 180J is used to detect temperature. In some embodiments, terminal 100 uses temperature detected by temperature sensor 180J to implement temperature processing strategy. For example, when temperature reported by temperature sensor 180J exceeds a threshold, terminal 100 implements performance reduction of a processor located near temperature sensor 180J to reduce power consumption and implement thermal protection. In another embodiments, when temperature is lower than another threshold, terminal 100 heats battery 142 to avoid abnormal shutdown of terminal 100 caused by low temperature. In other embodiments, when temperature is lower than yet another threshold, terminal 100 implements voltage boost of output voltage of battery 142 to avoid abnormal shutdown caused by low temperature.

[0344] Touch sensor 180K, also referred to as "touch panel". Touch sensor 180K can be disposed on display screen 194, and touch sensor 180K and display screen 194 form a touch screen, also referred to as "touch panel". Touch sensor 180K is used to detect touch operation acting on or near touch sensor 180K. Touch sensor 180K can transmit detected touch operation to an application processor to determine touch event type. Visual output related to touch operation can be provided through display screen 194. In other embodiments, touch sensor 180K can also be disposed on a surface of terminal 100, which is different from the position where display screen 194 is located.

[0345] Keys 190 include a power on key, a volume key, etc. Keys 190 can be mechanical keys. They can also be touch keys. Terminal 100 can receive key input and generate key signal input related to user settings and function control of terminal 100.

[0346] The motor 191 can generate a vibration prompt. The motor 191 can be used for incoming call vibration prompt, and can also be used for touch vibration feedback. For example, touch operations acting on different applications (such as taking pictures, playing audio, etc.) can correspond to different vibration feedback effects. The motor 191 can also correspond to different vibration feedback effects for touch operations acting on different regions of the display screen 194. Different application scenarios (such as time reminders, received messages, alarms, games, etc.) can also correspond to different vibration feedback effects. The touch vibration feedback effect can also support customization.

[0347] The indicator 192 can be an indicator light, which can be used to indicate a charging state, a power change, and can also be used to indicate a message, a missed call, a notification, etc.

[0348] The SIM card interface 195 is used to connect a SIM card. The SIM card can be inserted into or pulled out of the SIM card interface 195 to realize contact and separation with the terminal 100. The terminal 100 can support one or N SIM card interfaces, and N is a positive integer greater than 1. The SIM card interface 195 can support a Nano SIM card, a Micro SIM card, a SIM card, etc. 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 storage cards. The terminal 100 interacts with a network through the SIM card to realize functions such as calling and data communication.

[0349] The above describes the method provided by the present application in detail. In order to better implement the above scheme of the embodiments of the present application, the embodiments of the present application also provide a corresponding device or equipment.

[0350] The embodiments of the present application can divide the terminal 100 and the Beidou network device 200 into functional modules according to the above method examples. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The integrated module can be realized in the form of hardware or in the form of a software functional module. It should be noted that the division of the modules in the embodiments of the present application is illustrative, and is only a logical function division. Actual implementation can have another division manner.

[0351] The above will be described in detail below. Figures 13 to 16 The communication device of the embodiments of the present application is described in detail.

[0352] In the case of using an integrated unit, refer to Figure 13 , Figure 13FIG. 13 is a structural schematic diagram of a communication apparatus 1300 provided by an embodiment of the present application. The communication apparatus 1300 can be the terminal 100 in the above-described embodiments. Alternatively, the communication apparatus 1300 can be a chip / chip system, for example, a Beidou communication chip. As shown in FIG. 13, the communication apparatus 1300 can include a transceiver unit 1310 and a processing unit 1320. Figure 13

[0353] In one design, the transceiver unit 1310 can be configured to receive the MDCP PDU sent by the Beidou network device 200, and send the MDCP PDU to the Beidou network device 200.

[0354] The processing unit 1320 can be configured to divide the first message data aggregation layer service data unit MDCP SDU into M data aggregation layer protocol data units MDCP PDUs after the message data aggregation MDCP layer adds padding data and a redundancy length indication field to the first message data aggregation layer service data unit MDCP SDU.

[0355] The processing unit 1320 can also be configured to splice the M MDCP PDUs into the first message data aggregation layer service data unit MDCP SDU at the message data aggregation MDCP layer.

[0356] Optionally, the transceiver unit 1310 can also be configured to perform the functions and steps of the terminal 100 in the above-described method embodiments. Figure 11C Figure 11D

[0357] Optionally, the processing unit 1320 can also be configured to perform the functions and steps of the terminal 100 in the above-described method embodiments. Figure 11C Figure 11D

[0358] It should be understood that the communication apparatus 1300 in this design can correspondingly perform the method steps performed by the terminal 100 in the above-described embodiments, and thus will not be described here in detail.

[0359] In the case of using integrated units, refer to Figure 14 , Figure 14 FIG. 14 is a structural schematic diagram of a communication apparatus 1400 provided by an embodiment of the present application. The communication apparatus 1400 can be the Beidou network device 200 in the above-described embodiments. Alternatively, the communication apparatus 1400 can be a specific network element in the Beidou network device 200, for example, one network element or a combination of multiple network elements in the Beidou ground transceiver station 22, the Beidou center station 23, or the Beidou short message fusion communication platform 24. As shown in FIG. 14, the communication apparatus 1400 can include a transceiver unit 1410 and a processing unit 1420. Figure 14

[0360] ​​​​​​In one design, the transceiver 1410 can be configured to transmit MDCP PDUs to the terminal 100 and receive MDCP PDUs transmitted by the terminal 100.

[0361] The processing unit 1420 can be configured to split, at a message data aggregation MDCP layer, a first message data aggregation layer service data unit MDCP SDU into M data aggregation layer protocol data units MDCP PDUs.

[0362] The M is a positive integer; the M MDCP PDUs include a first MDCP PDU, and the first MDCP PDU includes a successor indication field in the header information, the successor indication field being used to indicate the order of the first MDCP PDU in the M MDCP PDUs; and the Beidou network device 200 transmits the first MDCP PDU.

[0363] In one possible implementation, the M is greater than 1, the successor indication field of the first MDCP PDU is a first value, the first value being used to indicate that the first MDCP PDU is the first MDCP PDU in the M MDCP PDUs; the M is greater than 1, the successor indication field of the first MDCP PDU is a second value, the second value being used to indicate that the first MDCP PDU is an intermediate MDCP PDU in the M MDCP PDUs; and the M is greater than 1, the successor indication field of the first MDCP PDU is a third value, the third value being used to indicate that the first MDCP PDU is the last MDCP PDU in the M MDCP PDUs.

[0364] In one possible implementation, the M is 1, 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 single MDCP PDU.

[0365] The processing unit 1420 can also be configured to concatenate, at the message data aggregation MDCP layer, the M MDCP PDUs into the first message data aggregation layer service data unit MDCP SDU.

[0366] Optionally, the transceiver 1410 can also be configured to perform the functions of the Beidou network device 200 in the methods shown in Figure 11C and Figure 11D with respect to transmitting and receiving.

[0367] Optionally, the processing unit 1420 can also be configured to perform the functions of the Beidou network device 200 in the methods shown in Figure 11C and Figure 11D with respect to protocol analysis and encapsulation and operation determination.

[0368] It should be understood that the communication apparatus 1400 in this design can correspond to perform the method steps performed by the Beidou network device 200 in the foregoing embodiments, and thus will not be described again here for brevity.

[0369] The terminal 100 and the Beidou network device 200 are introduced above, and it should be understood that any product with the functions of the terminal 100 described above and any product with the functions of the Beidou network device 200 described above fall within the protection scope of the embodiments of the present application. Figure 12 The terminal 100 described above can be implemented by a general bus architecture as a possible product form. Figure 13 The Beidou network device 200 described above can be implemented by a general bus architecture as a possible product form.

[0370] The terminal 100 described above can be implemented by a general bus architecture as a possible product form.

[0371] Referring to Figure 15 , Figure 15 is a structural schematic diagram of a communication apparatus 1500 provided by the embodiments of the present application. The communication apparatus 1500 can be the terminal 100 or a device therein. As shown in Figure 15 , the communication apparatus 1500 includes a processor 1501 and a transceiver 1502 in communication with the processor. The processor 1501 is a general-purpose processor or a special-purpose processor, etc. For example, it can be a baseband processor for satellite communication or a central processor. The baseband processor for satellite communication can be used to process satellite communication protocols and satellite communication data, and the central processor can be used to control the communication apparatus (such as a baseband chip, a terminal, a terminal chip, etc.), execute computer programs, and process data of the computer programs. The transceiver 1502 can be referred to as a transceiving unit, a transceiver, or a transceiving circuit, etc., and is used to implement the transceiving function. The transceiver 1502 can include a receiver and a transmitter. The receiver can be referred to as a receiver or a receiving circuit, etc., and is used to implement the receiving function. The transmitter can be referred to as a transmitter or a transmitting circuit, etc., and is used to implement the transmitting function. Optionally, the communication apparatus 1500 can further include an antenna 1503 and / or a radio frequency unit (not shown in the figure). The antenna 1503 and / or the radio frequency unit can be located inside the communication apparatus 1500, or can be separated from the communication apparatus 1400, i.e., the antenna 1503 and / or the radio frequency unit can be remotely deployed or distributed.

[0372] Optionally, the communication apparatus 1500 can include one or more memories 1504, which can have instructions stored thereon. The instructions can be computer programs, which can be run on the communication apparatus 1500, so that the communication apparatus 1500 performs the methods described in the foregoing method embodiments. Optionally, the memory 1504 can also store data. The communication apparatus 1500 and the memory 1504 can be separately arranged, or can be integrated together.

[0373] The processor 1501, the transceiver 1502, and the memory 1504 can be connected through a communication bus.

[0374] In one design, the communication apparatus 1500 can be configured to perform the functions of the terminal 100 in the foregoing embodiments: the processor 1501 can be configured to perform the above-mentioned Figure 11B the functions of the terminal 100 in the embodiments shown in the figures, which are related to protocol analysis and encapsulation and operation determination, and / or other processes for the technologies described herein; the transceiver 1502 can be configured to perform the above-mentioned Figure 11C and Figure 11D the functions of the terminal 100 in the embodiments shown in the figures, which are related to protocol analysis and encapsulation and operation determination, and / or other processes for the technologies described herein.

[0375] In any of the above designs, the processor 1501 can include a transceiver for implementing receiving and sending functions. For example, the transceiver can be a transceiver circuit, or an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit for implementing receiving and sending functions can be separate or integrated together. The above-mentioned transceiver circuit, interface, or interface circuit can be used for code / data reading and writing, or the above-mentioned transceiver circuit, interface, or interface circuit can be used for signal transmission or transfer.

[0376] In any of the above designs, the processor 1501 can store instructions, which can be a computer program, and the computer program can run on the processor 1501, so that the communication apparatus 1500 can perform the method steps performed by the terminal 100 in the above-mentioned method embodiments. The computer program can be fixed in the processor 1501, and in this case, the processor 1501 can be implemented by hardware.

[0377] In an implementation, the communication apparatus 1500 can include circuitry that can implement the functions of transmitting or receiving or communicating in the foregoing method embodiments. The processor and transceiver described in the present application can be implemented on an integrated circuit (IC), an analog IC, a radio frequency integrated circuit (RFIC), a mixed-signal IC, an application specific integrated circuit (ASIC), a printed circuit board (PCB), an electronic device, etc. The processor and transceiver can also be manufactured using various IC process technologies, such as complementary metal oxide semiconductor (CMOS), N-type metal oxide semiconductor (NMOS), positive channel metal oxide semiconductor (PMOS), bipolar junction transistor (BJT), bipolar CMOS (BiCMOS), silicon germanium (SiGe), gallium arsenide (GaAs), etc.

[0378] The scope of the communication apparatus described in the present application is not limited thereto, and the structure of the communication apparatus can not be limited by Figure 15 The communication apparatus 1500 can be a standalone device or can be a part of a larger device. For example, the communication apparatus 1500 can be:

[0379] (1) a standalone integrated circuit (IC), or a chip, or a chip system or subsystem;

[0380] (2) a set of one or more ICs, optionally including storage for storing data, computer programs, etc.

[0381] (3) an ASIC, such as a modem;

[0382] (4) a module that can be embedded within other devices;

[0383] (5) a receiver, a terminal, a smart terminal, a cellular phone, a wireless device, a handset, a mobile unit, a car device, a network device, a cloud device, an artificial intelligence device, etc.

[0384] (6) other, etc.

[0385] As a possible product form, any network element in the BeiDou network device 200 described in this application embodiment (e.g., BeiDou ground transceiver station 22, BeiDou central station 23, BeiDou short message fusion communication platform 24) can be implemented by a general bus architecture.

[0386] See Figure 16 , Figure 16 This is a schematic diagram of the structure of the communication device 1600 provided in an embodiment of this application. The communication device 1600 may be a BeiDou network device 200, or a device therein. Figure 16 As shown, the communication device 1600 includes a processor 1601 and a transceiver 1602 internally connected and communicating with the processor. The processor 1601 can be a general-purpose processor or a dedicated processor, such as a baseband processor or a central processing unit (CPU) for satellite communication. The baseband processor can process satellite communication protocols and data, while the CPU can control the communication device (e.g., a baseband chip), execute computer programs, and process data from those programs. The transceiver 1602, also known as a transceiver unit, transceiver, or transceiver circuit, is used to implement transceiver functions. The transceiver 1602 may include a receiver and a transmitter. The receiver, also known as a receiver circuit, is used to implement a receiving function; the transmitter, also known as a transmitter or transmitting circuit, is used to implement a 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 radio frequency unit may be located inside the communication device 1600 or separate from the communication device 1600, that is, the antenna 1603 and / or radio frequency unit may be deployed remotely or in a distributed manner.

[0387] Optionally, the communication device 1600 may include one or more memories 1604, which may store instructions, which may be computer programs, that can be executed on the communication device 1600 to cause the communication device 1600 to perform the methods described in the above method embodiments. Optionally, the memory 1604 may also store data. The communication device 1600 and the memory 1604 may be provided separately or integrated together.

[0388] The processor 1601, transceiver 1602, and memory 1604 can be connected via a communication bus.

[0389] In one design, the communication device 1600 can be used to perform the functions of the BeiDou network device 200 in the aforementioned embodiments: the processor 1601 can be used to perform the above-mentioned functions. Figure 11C and Figure 11DThe functions performed by the Beidou network device 200 in the illustrated embodiment regarding protocol parsing and encapsulation and operation determination and / or other processes for the techniques described herein; the transceiver 1602 can be used to perform the above-described Figure 11C and Figure 11D The functions performed by the Beidou network device 200 in the illustrated embodiment regarding protocol parsing and encapsulation and operation determination and / or other processes for the techniques described herein.

[0390] In any of the above designs, the processor 1601 can include a transceiver for implementing receiving and transmitting functions. For example, the transceiver can be a transceiver circuit, or an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit for implementing receiving and transmitting functions can be separate or integrated together. The above-mentioned transceiver circuit, interface, or interface circuit can be used for code / data reading and writing, or the above-mentioned transceiver circuit, interface, or interface circuit can be used for signal transmission or transfer.

[0391] In any of the above designs, the processor 1601 can store instructions, which can be a computer program, the computer program running on the processor 1601 can cause the communication device 1600 to perform the method steps performed by the terminal 100 in the above method embodiment. The computer program can be fixed in the processor 1601, in which case the processor 1601 can be implemented by hardware.

[0392] The embodiments of the present application also provide a computer readable storage medium, which stores computer program code, when the above processor executes the computer program code, causes the communication device to perform the method in any of the preceding embodiments.

[0393] The embodiments of the present application also provide a computer program product, when the computer program product runs on a computer, causes the computer to perform the method in any of the preceding embodiments.

[0394] The embodiments of the present application also provide 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 performs the method in any of the preceding embodiments.

[0395] The embodiments of the present application also provide a Beidou communication system, including a terminal 100 and a Beidou network device 200, the terminal 100 and the Beidou network device 200 can perform the method in any of the preceding embodiments.

[0396] It can be understood that the communication function of supporting short messages can also exist in other satellite systems. Therefore, the method described in the present application is also applicable to the communication of other satellite systems if other satellite systems also support the communication function of short messages.

[0397] The above-described embodiments are merely used to illustrate the technical solutions of the present application, but not for limiting the present application; even though the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: they can still make modifications to the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to some of the technical features; and 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.

[0398] In the above-described embodiments, according to the context, the term "when" can be interpreted as meaning "if" or "after" or "in response to determining" or "in response to detecting". Similarly, according to the context, the phrase "upon determining" or "if detecting (the stated condition or event)" can be interpreted as meaning "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)".

[0399] In the above-described embodiments, all or some of the steps can be implemented by using software, hardware, firmware or any combination thereof. When implemented by using software, the steps can be implemented by using one or combination of programs, instructions, codes, commands and the like. The programs can be stored in a computer readable storage medium, and implemented by using one or more computer processors. The computer readable storage medium can be a volatile (such as RAM, etc.) or non-volatile (such as ROM, magnetic disk, optical disk, etc.) medium. The computer readable storage medium can be a computer program product.

[0400] Those skilled in the art can understand that all or part of the processes in the above-mentioned method embodiments can be implemented by a computer program instructing relevant hardware to complete, the program can be stored in a computer readable storage medium, and the program can include the processes of the above-mentioned method embodiments when executed. The aforementioned storage medium includes ROM or random storage memory RAM, magnetic disc or optical disc and various storage code medium.

Claims

1. A data transmission control method in a Beidou communication system, characterized in that, The method comprises the following steps: The terminal divides the first message data aggregation layer service data unit (MDCP SDU) into M data aggregation layer protocol data units (MDCP PDUs) after adding padding data and a redundancy length indication field to the first MDCP SDU at a message data aggregation (MDCP) layer, wherein M is a positive integer; the MDCP PDUs include a first MDCP PDU, and the first MDCP PDU includes a successor indication field in the header information of the first MDCP PDU, wherein the successor 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 of claim 1, wherein: the successor indication field of the first MDCP PDU includes a first value, a second value or a third value, the first value is used to indicate that the first MDCP PDU is the first MDCP PDU in the M MDCP PDUs; the second value is used to indicate that the first MDCP PDU is an intermediate MDCP PDU in the M MDCP PDUs; the third value is used to indicate that the first MDCP PDU is the last MDCP PDU in 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, and the fourth value is used to indicate that the first MDCP PDU is a single MDCP PDU, and the M is 1.

4. The method of claim 3, wherein, The terminal divides the first message data aggregation layer service data unit (MDCP SDU) into M data aggregation layer protocol data units (MDCP PDUs) after adding padding data and a redundancy length indication field to the first MDCP SDU at a message data aggregation (MDCP) layer, and the method comprises the following steps: The terminal generates an application layer message at an application layer; The terminal divides the application layer message into the M MDCP PDUs after adding padding data and a redundancy length indication field to the first MDCP SDU at the MDCP layer.

5. The method of claim 4, wherein, Before the terminal divides the application layer message into the M MDCP PDUs after adding padding data and a redundancy length indication field to the first MDCP SDU at the MDCP layer, the method further comprises the following steps: The terminal obtains original data; The terminal compresses the original data to obtain compressed data at the application layer; The terminal encrypts the compressed data to obtain encrypted data at the application layer; The terminal adds message header information to the header of the encrypted data 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 the original data is compressed, and the encryption indication field is used to indicate the encryption algorithm used when the compressed data is encrypted.

6. The method of claim 5, wherein, The terminal sends the first MDCP PDU to a Beidou network device, and the method comprises the following steps: The terminal transmits the first MDCP PDU to a satellite link control (SLC) layer as a first SLC service data unit (SDU) of the SLC layer; The terminal divides the first SLC SDU into N SLC PDUs at the SLC layer, N being a positive integer; wherein the N SLC PDUs include a first SLC PDU, and frame header information of the first SLC PDU includes a service data unit alternation indication (SAI) field, a total frame number field and a frame sequence number field; the SAI field is used to indicate whether the first SLC PDU is retransmission data, the total frame number field is used to indicate a total number N of SLC PDUs included in the first SLC SDU, and the frame sequence number field is used to indicate a frame sequence number of the first SLC PDU in the first SLC SDU. The terminal sends the first SLC PDU to a Beidou network device.

7. The method of claim 6, wherein, The terminal sends the first SLC PDU to a Beidou network device, and specifically includes: The terminal issues the first SLC PDU from the SLC layer to a physical (PHY) layer as a first code block of the PHY layer; The terminal adds check bit information to a tail of the first code block at the PHY layer, and encodes the first code block and the check bit information to obtain first encoded data; The terminal inserts pilot information into the first encoded data at the PHY layer to obtain first pilot data; The terminal modulates the first pilot data and a synchronization header of the first pilot data at the PHY layer to obtain first modulated data and a first modulated synchronization header; The terminal spreads the first modulated data and the modulated synchronization header at the PHY layer to obtain first spread modulated data; The terminal sends the first spread modulated data as a first physical frame to the Beidou network device at the PHY layer.

8. The method according to any one of claims 4-7, characterized in that, The method further includes: 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, It includes: A Beidou network device receives M data convergence layer protocol data units (MDCP PDUs) sent by a terminal, M being a positive integer; wherein the M MDCP PDUs include a first MDCP PDU, and packet header information of the first MDCP PDU includes a successor indication field, which is used to indicate an order of the first MDCP PDU in the M MDCP PDUs; The Beidou network device splices the M MDCP PDUs at a message data convergence (MDCP) layer, removes a redundant length indication field and padding data after splicing to obtain a first MDCP service data unit (SDU), and the redundant length indication field is used to indicate a data length of the padding data.

10. The method of claim 9, wherein The successor indication field of the first MDCP PDU includes a first value, a second value or a third value, the first value is used to indicate that the first MDCP PDU is the first MDCP PDU in the M MDCP PDUs; The second value is used to indicate that the first MDCP PDU is the middle MDCP PDU in the M MDCP PDUs; The third value is used to indicate that the first MDCP PDU is the last MDCP PDU in 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, the fourth value is used to indicate that the first MDCP PDU is a single MDCP PDU, and the M is 1.

12. The method of claim 11, wherein, The Beidou network device splices the M MDCP PDUs into a first message data aggregation layer service data unit MDCP SDU at a message data aggregation MDCP layer, comprising: When the Beidou network device receives a second MDCP PDU, the successor indication of the second MDCP PDU indicates that the second MDCP PDU is the last one in 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 to the application layer as an application layer message from the MDCP layer.

13. The method of claim 12, wherein, The application layer message includes message header information and encrypted data, the message header information includes an encryption indication field and a compression indication field, the compression indication field is used to indicate the compression algorithm used by the terminal when compressing the original data into compressed data, and the encryption indication field is used to indicate the encryption algorithm used by the terminal when encrypting the compressed data into encrypted data; The method further comprises: The Beidou network device decrypts the encrypted data in the application layer message by using 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 by using the compression algorithm indicated by the compression indication field in the application layer message, to obtain the original data.

14. The method of claim 13, wherein, The method further comprises: The Beidou network device splices N SLC PDUs into a first SLC SDU at the SLC layer, and reports the first SLC SDU to the MDCP layer of the Beidou network device as the first MDCP PDU from the SLC layer of the Beidou network device; wherein the N SLC PDUs include a first SLC PDU, 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.

15. The method of claim 14, wherein, Before the Beidou network equipment reports the first SLC SDU to the MDCP layer of the Beidou network equipment as the first MDCP PDU from the SLC layer of the Beidou network equipment, the method further comprises: The Beidou network equipment acquires the first spread spectrum modulation data sent by the terminal at the PHY layer; The Beidou network equipment despreads the first spread spectrum modulation data at the PHY layer to obtain first modulation data and a first modulation synchronization header; The Beidou network equipment demodulates the first modulation data and the first modulation synchronization header at the PHY layer to obtain first pilot data and a first synchronization header; The Beidou network equipment removes the pilot information in the first pilot data at the PHY layer to obtain first encoding data; The Beidou network equipment decodes the first encoding data at the PHY layer to obtain a first encoding block and first check information; The Beidou network equipment checks the first encoding block based on the first check information at the PHY layer, and after the check succeeds, submits the first encoding block as the first SLC PDU in the first SLC SDU in the SLC layer of the Beidou network equipment from the PHY layer to the SLC layer of the Beidou network equipment.

16. The method according to any one of claims 12-15, characterized in that, The Beidou network equipment splices the M MDCP PDUs into a first message data aggregation layer service data unit MDCP SDU at the MDCP layer, comprising: The Beidou network equipment removes the successor indication field of each MDCP PDU in the M MDCP PDUs at the MDCP layer, and then splices the M MDCP PDUs into a first MDCP SDU according to the 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, Comprise: The Beidou network equipment divides the first message data aggregation layer service data unit MDCP SDU into M data aggregation layer protocol data units MDCP PDUs at the message data aggregation MDCP layer, M being a positive integer; wherein 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 equipment 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; the N SLC PDUs include a first SLC PDU, and 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 transmits the first SLC PDU.

18. The method of claim 17, wherein, a successor indication field of the first MDCP PDU includes a first value, a second value or a third value, the first value is used to indicate that the first MDCP PDU is a first MDCP PDU in the M MDCP PDUs; the second value is used to indicate that the first MDCP PDU is a middle MDCP PDU in the M MDCP PDUs; the third value is used to indicate that the first MDCP PDU is a last MDCP PDU in 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, and the fourth value is used to indicate that the first MDCP PDU is a single MDCP PDU, and the M is 1.

20. The method of claim 19, wherein, The Beidou network device divides a first message data aggregation layer service data unit (MDCP SDU) into M data aggregation layer protocol data units (MDCP PDUs) at a message data aggregation (MDCP) layer, and specifically includes: The Beidou network device generates an application layer message at an application layer; The Beidou network device divides 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 of claim 20, wherein, The Beidou network device generates an application layer message at an application layer, and specifically includes: 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 header of the encrypted data 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 a compression algorithm used when the original data is compressed, and the encryption indication field is used to indicate an encryption algorithm used when the compressed data is encrypted.

22. The method of claim 21, wherein, The N SLC PDUs further include a second SLC PDU, and the Beidou network device transmits the first SLC PDU to a terminal, including: The Beidou network device delivers the first SLC PDU and the second SLC PDU to a physical (PHY) layer; The Beidou network device generates a first physical frame from the first SLC PDU and a second physical frame from the second SLC PDU at the PHY layer; The Beidou network device transmits the first physical frame and the second physical frame.

23. The method of claim 22, wherein, The Beidou network device transmits the first physical frame and the second physical frame, comprising: The Beidou network device adds first check bit information at the tail of the first physical frame at the PHY layer, and encodes the first physical frame and the first check bit information to obtain first encoded data, adds second check bit information at the tail of the second physical frame, and encodes the second physical frame and the second check bit information to obtain second encoded data; The Beidou network device modulates the first reserved field of the first encoded data and the first encoded data to obtain first modulation data at the PHY layer, and modulates the second reserved field of the second encoded data and the second encoded data to obtain second modulation data; The Beidou network device spreads the first modulation data to obtain first spread modulation data at the PHY layer, and spreads the second modulation data to obtain second spread modulation data; The Beidou network device transmits the first spread modulation data and first pilot information of the first spread modulation data, and the second spread modulation data and second pilot information of the second spread modulation data at the PHY layer.

24. The method of any one of claims 20-23, wherein, 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.

25. A data transmission control method in a Beidou communication system, characterized in that, Comprising: The terminal receives N satellite link control layer protocol data units SLC PDU transmitted by the Beidou network device; The terminal splices the N SLC PDU into a first satellite link control layer service data unit SLC SDU at the SLC layer, and reports the first SLC SDU as the first data convergence layer protocol data unit MDCP PDU from the SLC layer of the Beidou network device to the message data convergence MDCP layer of the Beidou network device; wherein the N SLC PDU includes a 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 receiving the first user frame, and the first frame type field is used to indicate the frame type of the first user frame; the terminal splices the M MDCP PDU into a first message data convergence layer service data unit MDCP SDU at the MDCP layer, wherein the M MDCP PDU includes the first MDCP PDU, and the packet 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 PDU.

26. The method of claim 25, wherein, The successor indication field of the first MDCP PDU includes a first value, a second value or a third value, the first value is used to indicate that the first MDCP PDU is the first MDCP PDU in the M MDCP PDUs; The second value is used to indicate that the first MDCP PDU is the middle MDCP PDU in the M MDCP PDUs; The third value is used to indicate that the first MDCP PDU is the last MDCP PDU in the M MDCP PDUs.

27. The method of claim 25 or 26, wherein, The successor indication field of the first MDCP PDU is a fourth value, the fourth value is used to indicate that the first MDCP PDU is a single MDCP PDU, and the M is 1.

28. The method of claim 27, wherein, The terminal splices the M MDCP PDUs into a first message data aggregation layer service data unit MDCP SDU at a message data aggregation MDCP layer, including: When the terminal receives a second MDCP PDU, the successor indication of the second MDCP PDU indicates that the second MDCP PDU is the last one in 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 to the application layer as an application layer message from the MDCP layer.

29. The method of claim 28, wherein, 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 includes: The terminal decrypts the encrypted data in the application layer message by using the encryption algorithm indicated by the encryption indication field in the application layer message to obtain the compressed data at the application layer; The terminal decompresses the compressed data by using the compression algorithm indicated by the compression indication field in the application layer message to obtain the original data at the application layer.

30. The method of claim 29, wherein, Before the terminal 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 acquires first spread spectrum modulation data transmitted by the terminal at a physical PHY layer; The terminal despreads the first spread spectrum modulation data at the PHY layer to obtain first modulation data and a first modulation synchronization header; The terminal demodulates the first modulation data and the first modulation synchronization header at the PHY layer to obtain first pilot data and a first synchronization header; The terminal removes pilot information in the first pilot data to obtain first encoded data at the PHY layer; The Beidou network device decodes the first encoded data at the PHY layer to obtain a first encoded block physical frame and first check information; The terminal checks the first encoded block based on the first check information at the PHY layer, and after the check is successful, renders 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, where the first SLC PDU is a first user frame in the first encoded block with the same ID field as the terminal ID.

31. The method according to any one of claims 28-30, wherein, The terminal splices the M MDCP PDUs into a first message data convergence protocol (MDCP) service data unit (SDU) at a message data convergence protocol (MDCP) layer, including: The terminal splices the M MDCP PDUs into a first message data convergence protocol (MDCP) service data unit (SDU) at a message data convergence protocol (MDCP) layer, including:

32. A Beidou communication system, characterized in that, The terminal is configured to perform the data transmission control method in a Beidou communication system according to any one of claims 1-8 and / or 25-31, and the Beidou network device is configured to perform the data transmission control method in a Beidou communication system according to any one of claims 9-16 and / or 17-24.

33. A communications device, characterized by The communication device comprises one or more processors, one or more memories, and a transceiver; wherein the transceiver, the one or more memories, and the one or more processors are coupled, the one or more memories are configured to store computer program codes, and the computer program codes comprise computer instructions, which, when executed by the one or more processors, cause the communication device to perform the data transmission control method in a Beidou communication system according to any one of claims 9-16 and / or 17-24.

34. The communication apparatus of claim 33, wherein The communication device is a Beidou network device.

35. A communications device, characterized by The communication device comprises one or more processors, one or more memories, and a transceiver; wherein the transceiver, the one or more memories, and the one or more processors are coupled, the one or more memories are configured to store computer program codes, and the computer program codes comprise computer instructions, which, when executed by the one or more processors, cause the communication device to perform the data transmission control method in a Beidou communication system according to any one of claims 1-8 and / or 25-31.

36. The communication apparatus of claim 35, wherein The communication device is a terminal.

37. A computer readable storage medium, the computer readable storage medium storing instructions, when the instructions are run on a computer, cause the computer to perform the data transmission control method in a Beidou communication system according to any one of claims 9-16 and / or 17-24. 38.A computer readable storage medium having instructions stored therein, which when executed on a computer, cause the computer to perform the method of any one of claims 1-8, and / or 25-31.

39. A chip system applied to a terminal, characterized by comprising: comprising processing circuitry and interface circuitry configured to receive code instructions and transmit the code instructions to the processing circuitry, the processing circuitry configured to execute the code instructions to perform the method of any one of claims 1-8, and / or 25-31.

Images