Method, system and device for application layer acknowledgement transmission in a satellite communication system

Abstract

This application relates to the field of satellite communication technology and discloses an application layer receipt transmission method, system, and apparatus. After receiving an application layer message sent by a transmitting device, the receiving device can parse the application layer message and generate corresponding application layer receipt information based on the parsing result. The receiving device can send the application layer receipt information to the transmitting device, which can then confirm the parsing status of the application layer message by the receiving device (e.g., successful parsing, failed parsing). This establishes a reliable message transmission mechanism, ensuring that the transmitting device can obtain information about the parsing status of the application layer message by the receiving device.

Description

Technical Field

[0001] This application relates to the field of satellite communications, and in particular to a method, system and apparatus for transmitting application layer receipts in a satellite communication system. Background Technology

[0002] The BeiDou short message service is one of the distinctive features of the BeiDou Navigation Satellite System compared to other global positioning and navigation systems such as the US Global Positioning System (GPS) and Russia's Global Navigation Satellite System (GLONASS). It is particularly suitable for positioning and communication in areas such as oceans, deserts, grasslands, and uninhabited areas where mobile communication is unavailable, lacks coverage, or where communication systems are damaged. The BeiDou short message service communication system requires an upgraded technical architecture, and the communication protocol needs to be designed specifically for civilian services and equipment characteristics.

[0003] Currently, the BeiDou short message service communication system employs a feedback mechanism at the Satellite Link Control Protocol (SLC) layer to ensure that transmitted data packets are not lost. Specifically, at the end of the reception window, the receiving device can send an acknowledgment character (ACK) from the SLC layer to the sending device. The sending device can then determine the data packet reception status at the SLC layer based on the ACK. The sending device can retransmit data if it determines that the receiving device has not received a complete data packet. However, this only guarantees that the sending device can confirm the receiving device's data packet reception at the SLC layer; it cannot confirm the data packet parsing status at the application layer. Summary of the Invention

[0004] This application provides an application layer receipt transmission method, system, and related apparatus in a satellite communication system, which enables the establishment of a reliable message transmission mechanism between the transmitting and receiving devices, ensuring that the receiving device can parse the application layer message to obtain the original data, and ensuring normal communication between the transmitting and receiving devices.

[0005] Firstly, this application provides an application layer receipt transmission method in a BeiDou communication system, including:

[0006] The transmitting device sends the first message data aggregation layer protocol data unit (MDCP PDU) from the first application layer message to the receiving device. The header information of the first MDCP PDU includes a successor indication field. This successor indication field indicates the order of the first MDCP PDU within the first application layer message.

[0007] When the first MDCP PDU is the last MDCP PDU in the first application layer message, the sending device receives the first application layer acknowledgment information sent by the receiving device. This first application layer acknowledgment information is used to instruct the receiving device on the result of parsing the first application layer message.

[0008] The application-layer receipt transmission method in the BeiDou communication system provided in this application allows the receiving device to generate application-layer receipt information based on the result of parsing the application-layer message after receiving it from the sending device. The receiving device can then send the application-layer receipt information to the sending device, which can then determine the receiving device's parsing status of the application-layer message based on the application-layer receipt information.

[0009] In this way, the sending device can confirm whether the receiving device has received the original data from the sending device. The sending device can then clearly understand the data transmission status.

[0010] In one possible implementation, the sending device sends the first MDCP PDU in the first application layer message to the receiving device, specifically including:

[0011] The transmitting device sends the first MDCP PDU as the first Satellite Link Control Layer Service Data Unit (SLC SDU) of the transmitting device's SLC layer from the transmitting device's MDCP layer to the transmitting device's SLC layer.

[0012] The transmitting device splits the first SLC SDU into N Satellite Link Control Layer Protocol Data Units (SLCPDUs) at its SLC layer, where N is a positive integer. Each of the N SLCPDUs includes the first SLCPDU. The frame header information of the first SLCPDU includes a total frame count field and a frame sequence number field. The total frame count field indicates the total number N of SLCPDUs included in the first SLC SDU, and the frame sequence number field indicates the frame sequence number of the first SLC PDU within the first SLC SDU.

[0013] The transmitting device sends N SLC PDUs to the receiving device.

[0014] Specifically, the transmitting device sends the first MDCPPDU to the SLC layer as the first SLCSDU of the SLC layer and then splits the first SLCSDU into N SCLPDUs. (See also: [link to relevant documentation]). Figure 7 The embodiments shown are not described in detail here.

[0015] In one possible implementation, the first application layer acknowledgment information is also used to indicate that the receiving device has received all N SLCPDUs in the first SLCSDU. In this way, the sending device can determine, through the first application layer acknowledgment information, that the receiving device has received all SLCPDUs corresponding to the application layer message.

[0016] In one possible implementation, before the transmitting device receives the first application layer acknowledgment information sent by the receiving device, the method further includes: the transmitting device receiving a first acknowledgment character ACK sent by the receiving device. The first ACK is used to indicate that the receiving device has collected N SLCPDUs from the first SLCSDU.

[0017] In one possible implementation, before the transmitting device receives the first application layer acknowledgment information sent by the receiving device, the method further includes: the transmitting device receiving a second acknowledgment character ACK sent by the receiving device. The second ACK is used to indicate the frame sequence number of an SLC PDU that the receiving device has not received in the first SLC SDU.

[0018] The transmitting device retransmits the SLC PDU that the receiving device did not receive in the first SLC SDU to the receiving device.

[0019] This ensures that the receiving device receives the complete application layer message.

[0020] In one possible implementation, before the transmitting device receives the first acknowledgment character ACK sent by the receiving device, the method further includes: the transmitting device receiving a second acknowledgment character ACK sent by the receiving device. The second ACK is used to indicate the frame sequence number of an SLC PDU that the receiving device has not received in the first SLC SDU.

[0021] The transmitting device retransmits the SLC PDU that the receiving device did not receive in the first SLC SDU to the receiving device.

[0022] This ensures that the receiving device receives the complete application layer message.

[0023] In one possible implementation, the transmitting device sends N SLC PDUs to the receiving device, specifically including: the transmitting device sending the first SLCPDU from the transmitting device's SLC layer to the physical PHY layer as the first user frame of the transmitting device's PHY layer.

[0024] The transmitting device performs physical layer processing on the first user frame to obtain the first inbound data.

[0025] The transmitting device sends the first incoming data to the receiving device.

[0026] In one possible implementation, before the sending device sends the first MDCPPDU in the first application layer message to the receiving device, the method further includes: the sending device obtaining the first application layer message sent by the application layer of the sending device at the message data aggregation MDCP layer.

[0027] The transmitting device treats the first application layer message as an MDCP SDU at the MDCP layer and splits the MDCP SDU into M MDCP PDUs. Here, M is a positive integer. The M MDCP PDUs include the first MDCP PDU.

[0028] In one possible implementation, the method further includes: the transmitting device sending M MDCP PDUs from the MDCP layer to the SLC layer as M SLC SDUs of the SLC layer, wherein the M SLC SDUs include the first SLC SDU.

[0029] In one possible implementation, before the sending device obtains the first application layer message sent by the application layer of the sending device at the MDCP layer, the method further includes: the sending device obtaining raw data.

[0030] The transmitting device encodes and compresses the raw data at the application layer to obtain the first compressed data.

[0031] The sending device encrypts the first compressed data at the application layer to obtain the first encrypted data.

[0032] The sending device adds a message header to the first encrypted data header to obtain the first application layer message. The message header includes a compression indicator field and an encryption indicator field. The compression indicator field indicates the encoding compression algorithm used when compressing the original data, and the encryption indicator field indicates the encryption algorithm used when encrypting the first compressed data.

[0033] In one possible implementation, after the sending device receives the first application-layer acknowledgment information sent by the receiving device, the method further includes:

[0034] The sending device determines that the receiving device has failed to parse the first application layer message based on the first application layer acknowledgment information, and then the sending device retransmits the first application layer message to the receiving device.

[0035] In this way, when the sending device determines that the receiving device has failed to parse the application layer message, it can resend the application layer message, thus avoiding the situation where the receiving device fails to parse the application layer message due to data errors during transmission.

[0036] In one possible implementation, the first application layer receipt information includes a first parsing result, wherein the first parsing result is used to indicate that the receiving device failed to decrypt the first application layer message. After the sending device receives the first application layer receipt information sent by the receiving device, the method further includes:

[0037] The sending device and the receiving device negotiate key information.

[0038] The sending device encrypts the first compressed data based on the negotiated key information to obtain the second encrypted data.

[0039] The sending device sends a second application layer message containing the second encrypted data to the receiving device.

[0040] In one possible implementation, the first application layer receipt information includes a second parsing result, wherein the second parsing result is used to indicate that the receiving device failed to decode and decompress the application layer message. After the sending device receives the first application layer receipt information sent by the receiving device, the method further includes:

[0041] The sending device negotiates the codebook with the receiving device based on the second parsing result.

[0042] The transmitting device encodes and compresses the original data based on the negotiated codebook to obtain the second compressed data.

[0043] The sending device encrypts the second compressed data to obtain the third encrypted data.

[0044] The sending device sends a third application layer message to the receiving device. The third application layer message includes third encrypted data.

[0045] In one possible implementation, the aforementioned transmitting device is a terminal, and the receiving device is a BeiDou network device.

[0046] In one possible implementation, the aforementioned transmitting device is a BeiDou network device, and the receiving device is a terminal.

[0047] Secondly, this application provides an application layer receipt transmission method in a BeiDou communication system, including:

[0048] The receiving device receives the first MDCPPDU of the first application layer message sent by the sending device. The header information of the first MDCPPDU includes a successor indication field. This successor indication field indicates the order of the first MDCPPDU within the first application layer message.

[0049] After the receiving device determines that the first MDCPPDU is the last MDCPPDU among the M MDCPPDUs in the first application layer message, the receiving device obtains the first application layer message based on the first MDCPPDU. Here, M is a positive integer.

[0050] The receiving device generates a first application layer receipt, which is used to indicate the result of the receiving device parsing the first application layer message.

[0051] The receiving device sends the first application layer receipt information to the sending device.

[0052] In one possible implementation, before the receiving device generates the first application layer receipt information, the method further includes: the receiving device decrypting the first encrypted data in the first application layer message, and obtaining the first compressed data after successful decryption.

[0053] In one possible implementation, after the receiving device decrypts the first encrypted data in the first application layer message and obtains the first compressed data after successful decryption, the method further includes: the receiving device decoding and decompressing the first compressed data to obtain the original data.

[0054] In one possible implementation, before the receiving device generates the first application layer receipt information, the method further includes: the receiving device failing to decrypt the first encrypted data.

[0055] The receiving device generates a first application layer receipt. This first application layer receipt includes a first parsing result, which indicates that the receiving device has failed to decrypt.

[0056] In one possible implementation, before the receiving device generates the first application layer receipt information, the method further includes: the receiving device failing to decode or decompress the first compressed data.

[0057] The receiving device generates a first application layer receipt. This first application layer receipt includes a second parsing result, which indicates that the receiving device has failed to decode.

[0058] In one possible implementation, the first application layer receipt information includes a third parsing result, which is used to indicate that the receiving device has successfully parsed the application layer message.

[0059] In one possible implementation, the method further includes: when the receiving device is a BeiDou network device 200, the raw data can be sent to the cellular user equipment via the cellular network.

[0060] In one possible implementation, before the receiving device receives the first MDCPPDU of the first application layer message sent by the sending device, the method further includes: the receiving device obtaining the first inbound data sent by the sending device at the PHY layer.

[0061] The receiving device performs physical layer processing based on the first incoming data to obtain the first user frame.

[0062] The receiving device presents the first user frame as the first SLC PDU in the receiving device's SLC layer from the PHY layer to the receiving device's SLC layer.

[0063] In one possible implementation, after the receiving device presents the first user frame as the first SLC PDU in the receiving device's SLC layer from the PHY layer to the receiving device's SLC layer, the method further includes: the receiving device receiving X SLC PDUs from the first SLC SDU sent by the transmitting device, where X is a positive integer. The X SLC PDUs include the first SLC PDU, and the frame header information of the first SLC PDU includes a total frame count field and a frame sequence number field. The total frame count field indicates the total number N of SLCPDUs included in the first SLC SDU, where N is a positive integer, and the frame sequence number field indicates the frame sequence number of the first SLC PDU within the first SLC SDU.

[0064] When X is less than N, the receiving device sends a second ACK to the transmitting device, wherein the second ACK is used to indicate the frame sequence number of the SLC PDU that the receiving device did not receive in the first SLCSDU.

[0065] In one possible implementation, after the receiving device receives X SLC PDUs from the first SLC SDU sent by the transmitting device, the method further includes: when X equals N, the receiving device concatenates the X SLC PDUs into a first SLC SDU at the SLC layer, and reports the first SLC SDU as the first MDCP PDU of the MDCP layer from the receiving device's SLC layer to the receiving device's MDCP layer.

[0066] In one possible implementation, after the receiving device receives X SLC PDUs from the first SLC SDU sent by the transmitting device, the method further includes: when X equals N, the receiving device sends a first ACK to the transmitting device, wherein the first ACK is used to indicate that the receiving device has received all N SLC PDUs from the first SLC SDU.

[0067] In one possible implementation, after the receiving device determines that the first MDCPPDU is the last MDCPPDU among the M MDCPPDUs in the application layer message, the receiving device obtains the application layer message based on the first MDCPPDU. Specifically, the receiving device concatenates the M MDCP PDUs at the MDCP layer to obtain an MDCPSDU, and reports the MDCP SDU as an application layer message from the MDCP layer to the application layer.

[0068] In one possible implementation, the receiving device sends the first application layer receipt information to the sending device, specifically including: the receiving device sending the first application layer receipt information from the application layer of the receiving device to the SLC layer of the receiving device through a preset interface.

[0069] After the receiving device adds frame header information to the first application layer acknowledgment information at the SLC layer, it sends the first application layer acknowledgment information with the added frame header information to the physical layer, thus obtaining an acknowledgment frame. The frame header information includes a frame type field, which indicates the frame type of the user frame.

[0070] The receiving device sends an acknowledgment frame to the sending device.

[0071] In one possible implementation, the aforementioned transmitting device is a terminal, and the receiving device is a BeiDou network device.

[0072] In one possible implementation, the aforementioned transmitting device is a BeiDou network device, and the receiving device is a terminal.

[0073] Thirdly, this application provides a BeiDou communication system, including: a terminal and BeiDou network equipment; wherein:

[0074] The transmitting device is configured to transmit a first MDCPPDU of a first application layer message to the receiving device. The receiving device is configured to receive the first MDCPPDU. The receiving device is further configured to, after determining that the first MDCPPDU is the last MDCPPDU among M MDCPPDUs in the first application layer message, obtain the first application layer message based on the first MDCPPDU. Here, M is a positive integer. The receiving device is further configured to generate first application layer receipt information, which instructs the receiving device on the result of parsing the first application layer message. The receiving device is further configured to transmit the first application layer receipt information to the transmitting device. The transmitting device is configured to receive the first application layer receipt information.

[0075] In one possible implementation, the transmitting device may also execute the method in any of the possible implementations of the first aspect described above.

[0076] In one possible implementation, the receiving device may also execute the method in any of the possible implementations of the first aspect described above.

[0077] In one possible implementation, the aforementioned transmitting device is a terminal, and the receiving device is a BeiDou network device.

[0078] In one possible implementation, the aforementioned transmitting device is a BeiDou network device, and the receiving device is a terminal.

[0079] Fourthly, this application provides a communication device including one or more processors, one or more memories, and a transceiver. The transceiver, the one or more memories, and the one or more processors are coupled together. The one or more memories are used to store computer program code, which includes computer instructions. When the one or more processors execute the computer instructions, the communication device performs the method in any possible implementation of the first or second aspect described above.

[0080] The communication device can be a terminal or other product-type equipment.

[0081] Fifthly, this application provides a communication device including one or more processors, one or more memories, and a transceiver. The transceiver, the one or more memories, and the one or more processors are coupled together. The one or more memories are used to store computer program code, which includes computer instructions. When the one or more processors execute the computer instructions, the communication device performs the method in any possible implementation of the first or second aspect described above.

[0082] The communication device can be a BeiDou network device, or any network element or a combination of multiple network elements in a BeiDou network device.

[0083] In a sixth aspect, this application provides a computer storage medium including computer instructions that, when executed on a computer, cause the computer to perform the method in any possible implementation of the first aspect described above.

[0084] In a seventh aspect, this application provides a computer storage medium including computer instructions that, when executed on a computer, cause the computer to perform the method in any possible implementation of the second aspect described above.

[0085] Eighthly, this application provides a computer program product that, when run on a computer, causes the computer to perform the method in any possible implementation of the first aspect described above.

[0086] Ninthly, this application provides a computer program product that, when run on a computer, causes the computer to perform the method in any possible implementation of the second aspect described above.

[0087] In a tenth aspect, this application provides a chip or chip system applied to a terminal, including a processing circuit and an interface circuit. The interface circuit is used to receive code instructions and transmit them to the processing circuit. The processing circuit is used to execute the code instructions to perform the method in any possible implementation of the first or second aspect described above. Attached Figure Description

[0088] Figure 1A A schematic diagram of a BeiDou communication system provided in this application embodiment;

[0089] Figure 1B A schematic diagram of a BeiDou communication system provided in this application embodiment;

[0090] Figure 1C A schematic diagram of a BeiDou communication system provided in this application embodiment;

[0091] Figures 2A-2B This application provides a schematic diagram of an inbound protocol in a BeiDou communication system.

[0092] Figures 3A-3B This application provides a schematic diagram of an outbound protocol in a BeiDou communication system.

[0093] Figure 4 This application provides a schematic diagram of the ACK processing flow in a BeiDou communication system.

[0094] Figure 5 This application provides a schematic diagram of a protocol processing flow in a BeiDou communication system.

[0095] Figure 6A This application provides a schematic diagram of inbound transmission in a BeiDou communication system.

[0096] Figure 6B This application provides a schematic diagram of outbound transmission in a BeiDou communication system.

[0097] Figure 7 A schematic diagram of an application layer receipt mechanism in a BeiDou communication system provided in this application embodiment;

[0098] Figure 8 This application provides a schematic diagram of an application layer message in a BeiDou communication system.

[0099] Figure 9 This application provides a schematic diagram of a receipt frame in a BeiDou communication system.

[0100] Figure 10 This application provides a schematic diagram of a receipt frame in a BeiDou communication system.

[0101] Figure 11 A schematic diagram of an application layer receipt mechanism in a BeiDou communication system provided in this application embodiment;

[0102] Figure 12 A schematic diagram of a hardware structure provided for an embodiment of this application;

[0103] Figure 13 A flowchart illustrating an application layer receipt transmission method in a BeiDou communication system, provided as an embodiment of this application;

[0104] Figure 14 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0105] Figure 15 This is a schematic diagram of another communication device provided in an embodiment of this application;

[0106] Figure 16 This is a schematic diagram of another communication device provided in an embodiment of this application;

[0107] Figure 17 This is a schematic diagram of another communication device provided in an embodiment of this application. Detailed Implementation

[0108] The technical solutions in the embodiments of this application will be clearly and thoroughly described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B; the word "and / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone.

[0109] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.

[0110] The following describes a Beidou communication system 10 provided in an embodiment of this application.

[0111] like Figure 1A As shown, the BeiDou communication system 10 may include, but is not limited to, terminal 100, BeiDou short message satellite 21, BeiDou network equipment 200, short message center 25, and terminal 300, etc. Optionally, the BeiDou communication system 10 may also include national emergency rescue platform 26 and national emergency rescue center 27.

[0112] In this system, terminal 100 of the BeiDou network can send short message information to terminal 300 of the cellular network. Specifically, terminal 100 can first send short message information to BeiDou short message satellite 21. BeiDou short message satellite 21 only acts as a relay, directly forwarding the short message information sent by terminal 100 to BeiDou network equipment 200 on the ground. BeiDou network equipment 200 can parse the short message information forwarded by the satellite according to the BeiDou communication protocol and forward the message content parsed from the short message information to short message service center (SMSC) 25. Short message service center 25 can forward the message content to terminal 300 through traditional cellular communication network. BeiDou network equipment 200 can also send emergency rescue messages sent by terminal 100 to National Emergency Rescue Center 27 through National Rescue Platform 26.

[0113] The cellular network terminal 300 (which can be referred to as cellular user equipment) can also send short message information to the BeiDou network terminal 100. Terminal 300 can send short messages to the Short Message Service (SMS) center 25 via a traditional cellular communication network. The SMS center 25 can forward the short messages from terminal 300 to the BeiDou network device 200. The BeiDou network device 200 can then relay the short messages from terminal 300 to terminal 100 via the BeiDou short message satellite 21.

[0114] The aforementioned BeiDou network equipment 200 may include a BeiDou ground transmitting / receiving station 22, a BeiDou central station 23, and a BeiDou short message fusion communication platform 24. The BeiDou ground transmitting / receiving station 22 may include one or more devices with transmitting and receiving functions, or it may include one or more devices with both transmitting and receiving functions; this is not limited here. The BeiDou ground transmitting / receiving station 22 can be used by the BeiDou network equipment 200 for data processing at the physical layer protocol (PHY). The BeiDou central station 23 can be used by the BeiDou network equipment 200 for data processing at the satellite link control layer and message data convergence protocol (MDCP). The BeiDou short message fusion communication platform 24 can be used for data processing at the application layer protocol (APP).

[0115] In the aforementioned BeiDou communication system 10, the transmitting device can send data to the receiving device. After receiving a data frame from the transmitting device, the receiving device can send an acknowledgment character (ACK) from the SLC layer to the transmitting device. The transmitting device can determine whether the receiving device has successfully received the data frame based on the ACK.

[0116] The following describes an ACK mechanism for a BeiDou communication system 10 provided in the embodiments of this application.

[0117] Figure 1B This application illustrates a data inbound transmission process in a BeiDou communication system provided by an embodiment of the present application.

[0118] like Figure 1B As shown, data inbound can refer to terminal 100 sending data to BeiDou network device 200. For example, terminal 100 can send data frames to BeiDou ground transceiver station 22. BeiDou ground transceiver station 22 can send the data frames to BeiDou central station 23. BeiDou central station 23 can aggregate the data frames into application layer messages and report them to BeiDou short message fusion communication platform 24. After receiving the data frames sent by terminal 100, BeiDou central station 23 can return an SLC layer ACK to terminal 100. This ACK can be used to indicate whether BeiDou network device 200 has successfully received the data frames sent by terminal 100. Here, the data frame can refer to the SLC PDU in this embodiment.

[0119] Figure 1C This illustration shows the data outgoing transmission process in a BeiDou communication system provided in an embodiment of this application.

[0120] like Figure 1C As shown, data outbound can refer to the BeiDou network device 200 sending data to the terminal 100. For example, the BeiDou short message fusion communication platform 24 can send application layer messages to the BeiDou central station 23; then, the BeiDou central station 23 can split the application layer messages into one or more data frames, and send these one or more data frames to the terminal 100 through the BeiDou ground transceiver station 22 and the BeiDou short message satellite 21. After receiving the data frame sent by the BeiDou network device 200, the terminal 100 can return an SLC layer ACK to the BeiDou network device 200. This ACK can be used to indicate whether the terminal 100 has successfully received the data frame sent by the BeiDou network device 200. The data frame can refer to the SLC PDU in this embodiment.

[0121] In one possible implementation, during outbound transmission, the BeiDou network device 200 can concatenate data frames sent to multiple terminals at the SLC layer to obtain outbound data, and then send the outbound data to all terminals. Therefore, the outbound resources of the BeiDou network device 200's SLC layer are strained, and processing retransmitted data would consume computational resources. Therefore, the BeiDou network device 200 can clear the cache of previously sent data after sending it out. Similarly, after receiving a data frame sent by the BeiDou network device 200, the terminal 100 does not return an AKC (Acceptable Call) at the SLC layer to the BeiDou network device 200. There is no SLC layer retransmission mechanism during outbound transmission.

[0122] The following describes a protocol architecture for inbound data of a Beidou communication system 10 provided in this application embodiment.

[0123] Figure 2A This paper illustrates a schematic diagram of the protocol encapsulation architecture for inbound data of a Beidou communication system 10 provided in an embodiment of this application.

[0124] like Figure 2A As shown, the BeiDou message transmission protocol layer on terminal 100 can be divided into application layer, message data aggregation layer, satellite link control layer and physical layer.

[0125] When terminal 100 sends data to BeiDou network device 200, the workflow of the BeiDou message transmission protocol on terminal 100 can be as follows:

[0126] At the APP layer, terminal 100 can encode and compress the raw data to obtain compressed data. Terminal 100 can encrypt the compressed data to obtain encrypted data. A message header is then added to the encrypted data to obtain the application layer message. The raw data may include, but is not limited to, user-input text information, an indication of the number of users receiving data, the IDs of the receiving users, the location information of terminal 100, voice, images, animations, etc. The message header information may include, but is not limited to, a compression indication field, an encryption indication field, etc. The compression indication field indicates the type of encoding compression algorithm used by terminal 100 to compress the data. The encryption indication field indicates the type of encryption algorithm used by terminal 100 to encrypt the data.

[0127] Optionally, after encoding and compressing the original data to obtain compressed data, terminal 100 may add the aforementioned compression indication field before the compressed data. Terminal 100 then uses a key to encrypt the compressed data with the compression indication field added, thus obtaining encrypted data.

[0128] At the MDCP layer, terminal 100 can obtain application layer messages sent by the APP layer through the inter-layer interface and treat the application layer messages as a MDCP layer service data unit (SDU), abbreviated as MDCPSDU. At the MDCP layer, terminal 100 can add padding data to the end of the MDCPSDU to a specified length and add a redundancy length indicator field to the MDCP SDU. This redundancy length indicator field can be used to indicate the length of the padding data. Terminal 100 can split the padding data and the MDCP SDU with the added redundancy length indicator field into one or more fixed-length MDCP segments (M_segment), and add a successor indicator field to the header of each MDCP segment to obtain the MDCP layer protocol data unit (PDU), abbreviated as MDCPPDU. That is, the MDCP PDU includes the M_segment and the successor indicator field. The successor indicator field can be used to indicate the order of the current MDCPPDU among multiple MDCPPDUs in the same MDCPSDU, or the unique MDCPPDU that is an MDCPSDU.

[0129] At the SLC layer, terminal 100 can obtain the MDCPPDU sent by the MDCP layer through the inter-layer interface, which serves as the SDU of the SLC layer, i.e., SLCSDU. At the SLC layer, terminal 100 can segment the SLCSDU into one or more (e.g., four) fixed-length SLC segment data (S_segment), and add frame header information to the header of each S_segment to obtain the PDU of the SLC layer, i.e., SLCPDU. The frame header information includes a Service Data Unit Alternated Indicator (SAI) field, a total frame count field, and a frame sequence number field.

[0130] The SAI field can be used to indicate whether the SLC PDU belongs to an unsent SLC SDU.

[0131] The total number of frames field can be used to indicate the total number of SLCPDUs included in the SLC SDU to which this SLC PDU belongs.

[0132] The frame sequence number field can be used to indicate the sequence number of the SLC PDU within its respective SLC SDU.

[0133] At the PHY layer, terminal 100 can obtain the SLC PDU issued by the SLC layer through the inter-layer interface and use the SLC PDU as a user frame for the PHY layer. Terminal 100 can perform physical layer processing on the user frame (e.g., encoding, pilot interpolation, modulation, spread spectrum, etc.) to obtain inbound data. Then, terminal 100 can send the inbound data to BeiDou short message satellite 21, which will relay it to BeiDou network equipment 200.

[0134] Figure 2B This paper illustrates a schematic diagram of the protocol parsing architecture for inbound data of a Beidou communication system 10 provided in an embodiment of this application.

[0135] like Figure 2B As shown, the BeiDou message transmission protocol layer on the BeiDou network device 200 can be divided into the application layer, message data aggregation layer, satellite link control layer, and physical layer. The BeiDou network device 200 may include, but is not limited to, the BeiDou ground transceiver station 22, the BeiDou central station 23, and the BeiDou short message fusion communication platform 24. The BeiDou ground transceiver station 22 can be used to handle the protocol processing of the PHY layer. The BeiDou central station 23 can be used to handle the protocol processing of the SLC layer and MDCP layer. The BeiDou short message fusion communication platform 24 can be used to handle the protocol processing of the APP layer.

[0136] When terminal 100 sends data to BeiDou network device 200, the workflow of the BeiDou message transmission protocol on terminal 100 can be as follows:

[0137] At the PHY layer, the BeiDou network device 200 can acquire the inbound data sent by the terminal 100. The BeiDou network device 200 performs physical layer processing on the inbound data (e.g., despreading, demodulation, pilot removal, decoding, etc.) to obtain user frames. The BeiDou network device 200 can then present the user frames to the SLC layer through the inter-layer interface as SLC PDUs for the SLC layer.

[0138] At the SLC layer, the BeiDou network device 200 can combine SLC PDUs belonging to the same SLC SDU into a single SLC SDU based on the frame header information of the SLC PDU. The BeiDou network device 200 can then present the SLC SDU to the MDCP layer through the inter-layer interface, serving as the MDCP PDU for the MDCP layer.

[0139] At the MDCP layer, the BeiDou network device 200 can concatenate all MDCP PDUs belonging to the same MDCP SDU according to their reception time, and remove the padding data and redundancy length indicator field from the concatenated MDCPPDU to obtain the MDCPSDU. The BeiDou network device 200 can then present the MDCP SDU to the APP layer through the inter-layer interface, serving as the application layer message received by the APP layer.

[0140] At the APP layer, the BeiDou network device 200 can decrypt the encrypted data in the application layer message based on the message header to obtain compressed data. The BeiDou network device 200 can then decompress and decode the compressed data to obtain the original data.

[0141] In the embodiments of this application, the above protocol processing procedure is only an example for illustration, and this application does not limit the specific operation of protocol processing.

[0142] The following describes a protocol architecture for outbound data of a Beidou communication system 10 provided in this application embodiment.

[0143] Figure 3A This paper illustrates a schematic diagram of the protocol encapsulation architecture for outbound data of a Beidou communication system 10 provided in an embodiment of this application.

[0144] like Figure 3A As shown, the BeiDou message transmission protocol layer on the BeiDou network equipment 200 can be divided into the application layer, message data aggregation layer, satellite link control layer, and physical layer.

[0145] When BeiDou network device 200 sends data to terminal 100, the workflow of the BeiDou message transmission protocol on BeiDou network device 200 can be as follows:

[0146] At the APP layer, the BeiDou network device 200 can encode and compress the raw data to obtain compressed data. The BeiDou network device 200 can then encrypt the compressed data to obtain encrypted data. A message header is added before the encrypted data to obtain the application layer message. The raw data may include, but is not limited to, data sent by a third-party server (e.g., short message center 25), text, semaphores, voice, images, animations, etc. The message header information may include, but is not limited to, compression indication fields, encryption indication fields, etc. The compression indication field indicates the type of encoding compression algorithm used by the BeiDou network device 200 to compress the data. The encryption indication field indicates the type of encryption algorithm used by the BeiDou network device 200 to encrypt the data.

[0147] Optionally, the BeiDou network device 200 can encode and compress the original data, and after obtaining compressed data, add the aforementioned compression indication field before the compressed data. The BeiDou network device 200 then uses a key to encrypt the compressed data with the added compression indication field, obtaining encrypted data.

[0148] At the MDCP layer, the BeiDou network device 200 can obtain application layer packets sent from the APP layer through the inter-layer interface and treat each application layer packet as an MDCP SDU. The BeiDou network device 200 can split the MDCP SDU into one or more fixed-length MDCP segments (M_segment) and add a successor indication field to the header of each MDCP segment to obtain an MDCP PDU. That is, an MDCP PDU includes an M_segment and a successor indication field. The successor indication field can be used to indicate the order of the current MDCPPDU within the same MDCPSDU.

[0149] At the SLC layer, the BeiDou network device 200 can obtain the MDCPPDU sent by the MDCP layer through the inter-layer interface, which is then used as the SLCSDU. The BeiDou network device 200 can segment the SLCSDU into one or more (e.g., four) fixed-length SLC segment data (S_segment), and add frame header information to the header of each S_segment to obtain the SLC PDU. A description of the SLC layer of the BeiDou network device 200 can be found above. Figure 2A The embodiments described herein will not be repeated here.

[0150] At the PHY layer, the BeiDou network device 200 can obtain the SLC PDU issued by the SLC layer through the inter-layer interface, which serves as the user frame. The BeiDou network device 200 can concatenate multiple user frames or a single user's user frames (also known as data frames), adding a frame header (e.g., version number) and a checksum to obtain a physical frame. The BeiDou network device 200 can then perform physical layer processing on the physical frame (e.g., encoding, pilot insertion, modulation, spread spectrum, etc.) to obtain the encoded data for the message branch (S2C-d branch). The BeiDou network device 200 can combine the encoded data of the S2C-d branch with the pilot data (also known as subcode) of the pilot branch (S2C-p branch) to form pilot encoded data, i.e., outgoing data. This outgoing data is then sent to the BeiDou short message satellite 21, which relays it to one or more terminals. It is understood that the pilot data of the S2C-p branch is related to the satellite beam. When the satellite beam information is known, the pilot data of the S2C-p branch is also known and does not require decoding. However, the encoded data of the S2C-d branch requires decoding.

[0151] Figure 3B This paper illustrates a schematic diagram of the protocol parsing architecture for outbound data of a Beidou communication system 10 provided in an embodiment of this application.

[0152] like Figure 3B As shown, the BeiDou message transmission protocol layer on terminal 100 can be divided into application layer, message data aggregation layer, satellite link control layer and physical layer.

[0153] At the PHY layer, terminal 100 can capture the encoded data of the S2C-d tributary based on the subcode of the S2C-p tributary sent by BeiDou network device 200. After capturing the encoded data of the S2C-d tributary, terminal 100 can perform physical layer processing (e.g., despreading, demodulation, pilot removal, decoding, etc.) to obtain physical frames. Terminal 100 can then extract user frames belonging to terminal 100 from the physical frames. Terminal 100 can then present the user frames to the SLC layer through the inter-layer interface as SLC PDUs for the SLC layer.

[0154] At the SLC layer, when the user frame received by terminal 100 is a general data frame, terminal 100 can concatenate SLC PDUs belonging to the same SLC SDU into a single SLC SDU. Terminal 100 can then present the SLC SDU to the MDCP layer through the inter-layer interface, serving as the MDCP PDU for the MDCP layer. When the user frame received by terminal 100 is an ACK frame, terminal 100 can retransmit the current SLCSDU, send the next SLCSDU, or stop sending SLCSDUs.

[0155] At the MDCP layer, terminal 100 can concatenate one or more MDCP PDUs into an MDCP SDU. Terminal 100 can then present the MDCP SDU to the APP layer through the inter-layer interface, serving as an application layer message received by the APP layer.

[0156] At the APP layer, terminal 100 can decrypt the application layer message to obtain compressed data. Terminal 100 then decompresses and decodes the compressed data to obtain the original data.

[0157] In the embodiments of this application, the above protocol processing procedure is only an example for illustration, and this application does not limit the specific operation of protocol processing.

[0158] The ACK processing flow provided in the embodiments of this application is described below.

[0159] Figure 4 A schematic diagram of the ACK processing flow in the BeiDou communication system 10 provided in this embodiment is shown.

[0160] like Figure 4As shown, the transmitting device can generate application layer messages at the application layer. Then, the transmitting device can send the application layer messages to the MDCP layer as MDCP SDUs. Next, the transmitting device can packetize the MDCPSDU into multiple MDCPPDUs at the MDCP layer. Then, the transmitting device can send the MDCP PDUs to the SLC layer as SLC SLCSDUs, and at the SLC layer, the SLCSDUs are framed into N SLCPDUs, where N is a positive integer (e.g., 4). The frame header information of the SLCPDU includes a Service Data Unit Alternated Indicator (SAI) field, a total frame count field, and a frame sequence number field. The SAI field indicates whether the SLC PDU belongs to an untransmitted SLC SDU. The total frame count field indicates the total number of SLCPDUs included in the SLC SDU to which the SLC PDU belongs. The frame sequence number field indicates the sequence number of the SLC PDU within its SLC SDU.

[0161] The transmitting device can send the SLCPDU of the SLCSDU to the receiving device. The receiving device can determine whether it has received all the SLCPDUs of the SLCSDU based on the frame header information of the SLCPDU.

[0162] If the receiving device determines, based on the frame header information, that it has received all SLCPDUs of the SLCSDU, it can send a first ACK to the transmitting device. The first ACK can indicate that the receiving device has received all SLCPDUs of the SLCSDU. After receiving the first ACK, the transmitting device can determine the SLCPDUs of the SLCSDU received by the receiving device at the SLC layer. If the transmitting device sends the SLCPDU of the last SLCSDU of the MDCPSDU, it can terminate the transmission operation. If the transmitting device sends the SLCPDU of a non-last SLCSDU of the MDCPSDU, it can continue transmitting the SLCPDU of the next SLCSDU of the MDCPSDU.

[0163] If the receiving device determines, based on the frame header information, that all SLCPDUs of the SLCSDU have not been received, the receiving device can send a second ACK to the transmitting device. The second ACK can be used to indicate that the receiving device has not received all SLCPDUs of the SLCSDU. Upon receiving the second ACK, the transmitting device can retransmit all SLCPDUs of that SLCSDU to the receiving device.

[0164] In one possible implementation, the second ACK can also indicate the frame sequence number of the unreceived SLCPDU. After receiving the second ACK, the transmitting device can retransmit the unreceived SLCPDU indicated by the second ACK to the receiving device.

[0165] For example, such as Figure 4 As shown, after receiving the second ACK, the transmitting device retransmits the SLCPDU that the receiving device did not receive. After receiving the SLCPDU, the receiving device can send the first ACK back to the transmitting device.

[0166] During the inbound process, the sending device can be terminal 100, and the receiving device can be BeiDou network device 200. During the outbound process, the sending device can be BeiDou network device 200, and the receiving device can be terminal 100.

[0167] In this way, even if the data sent by the sending device to the receiving device is lost, the data transmission process can still be guaranteed to continue normally, and the receiving device can receive the data sent by the sending device.

[0168] In one possible implementation, since many services in the BeiDou communication system are bursty, terminal 100 does not need to maintain constant communication with BeiDou network device 200. Terminal 100 only needs to send a service request to BeiDou network device 200 during communication, and BeiDou network device 200 sends a service response to terminal 100 based on the service request. If BeiDou network device 200 has an SLC layer retransmission mechanism, the computational burden is heavy, and the beneficial effect is not obvious. When the sending device is BeiDou network device 200 and the receiving device is terminal 100, the sending device does not retransmit the SLCSDU SLCPDU to the receiving device after receiving the second ACK. Optionally, the sending device can also stop sending SLCSDU to BeiDou network device 200. In this way, BeiDou network device 200 can better save limited transmission resources by not retransmitting data at the SLC layer.

[0169] Further optionally, when the transmitting device is BeiDou network device 200 and the receiving device is terminal 100, in order to further save the air interface resources of BeiDou network device 200, terminal 100 may not send SLC layer feedback ACK (including first ACK and second ACK) to BeiDou network device.

[0170] Figure 5 This illustration shows a schematic diagram of the protocol processing flow of the MDCP layer and SLC layer of the BeiDou communication system 10 provided in this embodiment of the application. During the inbound process, the transmitting device is terminal 100, and the receiving device is BeiDou network device 200. During the outbound process, the transmitting device is BeiDou network device 200, and the receiving device is terminal 100.

[0171] 1. The protocol encapsulation process of the transmitting device for transmitting data at the MDCP layer.

[0172] like Figure 5 As shown, at the MDCP layer, the transmitting device can split the MDCP SDU into one or more fixed-length MDCP segment data (M_segment), and add a successor indication field to the header of each MDCP segment data to obtain the MDCPPDU, that is, the MDCP PDU includes M_segment and successor indication field.

[0173] It should be noted that during the inbound process, firstly, the sending device can add padding data and a redundancy length indicator field to the MDCPSDU. Then, the sending device can split the MDCPSDU with added padding data and redundancy length indicator field into one or more fixed-length MDCP segments, and add a follow-up indicator field to the header of each MDCP segment to obtain the MDCP PDU.

[0174] It should be noted that during the outbound process, the transmitting device can directly split the MDCPSDU into one or more fixed-length MDCP segment data, and add a successor indicator field to the header of each MDCP segment data to obtain the MDCP PDU.

[0175] The transmitting device can store the split MDCP PDUs into the MDCP layer transmit buffer (MDCP Txbuffer) in order from high-bit to low-bit:

[0176] The successor indicator field can have a data length of 2 bits. The meaning of the successor indicator field's value can be as follows:

[0177] 01: Indicates that this MDCP PDU is the starting MDCP PDU among multiple MDCP PDUs in this MDCP SDU;

[0178] 10: This indicates that the MDCP PDU is the middle MDCP PDU among multiple MDCP PDUs in this MDCP SDU, that is, it refers to the other MDCP PDUs in this MDCP SDU besides the starting MDCP PDU and the last MDCP PDU;

[0179] 11: This indicates that the MDCP PDU is the last MDCP PDU among multiple MDCP PDUs in this MDCP SDU;

[0180] 00: This indicates that the MDCP PDU is the only MDCP PDU in this MDCP SDU.

[0181] For example, such as Figure 5 As shown, terminal 100 can split an MDCP SDU into three MDCP PDUs, which are named MDCP PDU0, MDCP PDU1, and MDCP PDU2 in descending order of high-order bits. Since MDCP PDU0 is the starting MDCP PDU in the current MDCP SDU, terminal 100 can set the value of the successor indicator field in MDCP PDU0 to "01". Since MDCP PDU1 is the middle MDCP PDU in the current MDCP SDU, terminal 100 can set the value of the successor indicator field in MDCP PDU1 to "10". MDCP PDU2 is the last MDCP PDU in the current MDCP SDU, and terminal 100 can set the value of the successor indicator field in MDCP PDU2 to "11".

[0182] 2. The protocol encapsulation process of the transmitting device for transmitting data at the SLC layer.

[0183] At the SLC layer, the transmitting device can control the SLC PDU transmission strategy, including the initial transmission and retransmission of SLC PDUs, through the SLC layer's state controller. The transmitting device can also control the transmission and retransmission of SLCPDUs based on the receiving device's reception feedback (e.g., ACK). The transmitting device can obtain MDCPPDUs from the MDCP layer via the inter-layer interface, using them as SLCSDUs. Specifically, the transmitting device will only obtain the next MDCP PDU from the MDCP layer as the next SLC SDU and send it to the receiving device after successfully sending the previous SLC SDU to the receiving device and confirming successful reception.

[0184] For example, the sending device can send MDCPPDU0 from MDCP PDU0, MDCP PDU1, and MDCP PDU2 to the SLC layer. At the SLC layer, the sending device first obtains MDCP PDU0 from the MDCP layer through the inter-layer interface. The sending device can then send MDCP PDU0 as the first SLC SDU (i.e., SLCSDU0) of the SLC layer in this message transmission process to the receiving device. After the sending device determines that the receiving device has sent the data of SLC SDU0 to the receiving device, the sending device can obtain MDCP PDU1 from the MDCP layer and send MDCP PDU1 as the second SLC SDU (i.e., SLCSDU1) of this message transmission process to the receiving device. After the sending device determines that the receiving device has sent the data of the second SLC SDU to the receiving device, the sending device can obtain MDCP PDU2 from the MDCP layer and send MDCP PDU2 as the last SLC SDU of this message transmission process to the receiving device.

[0185] Optionally, the transmitting device can send all MDCPPDUs of the MDCPSDU of the MDCP layer to the SLC layer via the inter-layer interface, as SLCSDUs of the SLC layer. Specifically, after the transmitting device sends the previous SLC SDU to the receiving device and confirms that the receiving device has successfully received it, it will send the next SLCSDU to the receiving device.

[0186] For example, the sending device can send MDCP PDU0, MDCP PDU1, and MDCP PDU2 to the SLC layer. At the SLC layer, the sending device first obtains MDCP PDU0, MDCP PDU1, and MDCP PDU2 sent by the MDCP layer through the inter-layer interface. The sending device can use MDCP PDU0 as the first SLC SDU (i.e., SLCSDU0) in this message transmission process, MDCP PDU1 as the second SLC SDU (i.e., SLCSDU1), and MDCP PDU2 as the third SLC SDU (i.e., SLCSDU2). After the sending device determines that it has successfully sent the data of SLC SDU0 to the receiving device, it can send SLCSDU1 to the receiving device, and so on.

[0187] The above examples are merely for illustrative purposes and should not be construed as limiting the scope of this application.

[0188] At the SLC layer, the transmitting device can segment an SLCSDU into one or more fixed-length SLC segment data (S_segment), and add frame header information to the header of each S_segment to obtain an SLC PDU. The frame header information includes the SAI field, the total number of frames field, and the frame sequence number field.

[0189] The SAI field can occupy 1 bit. The value of the SAI field can be "0" or "1". The transmitting device can determine whether the SLC PDU to be transmitted belongs to an SLC SDU that has not been transmitted before. If so, the transmitting device can set the value of the SAI field in the SLC PDU to be different from the value of the SAI field in the previous SLC SDU session (including the initial transmission session or the retransmission session). If not, the transmitting device 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 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 previous SLC SDU session, it indicates that the SLC PDU is retransmitted data.

[0190] For example, the sending device needs to transmit three SLC SDUs during the entire application layer message transmission process. Each SLC SDU may include four SLC PDUs. Specifically, in the first SLC SDU (i.e., SLCSDU0), the SAI field values ​​of all four SLC PDUs can be "0", in the second SLC SDU (i.e., SLCSDU1), the SAI field values ​​of all four SLC PDUs can be "1", and in the third SLC SDU, the SAI field values ​​of all four SLC PDUs can be "0".

[0191] The above examples are merely for illustrative purposes and should not be construed as limiting the scope of this application.

[0192] 3. The protocol parsing process of the receiving device at the SLC layer for the received data.

[0193] At the SLC layer, after receiving the SLC PDU from the transmitting device, the receiving device can determine whether it has received all the SLC PDUs in an SLC SDU based on the frame header information of the SLC PDU.

[0194] If it is determined that all SLC PDUs in an SLC SDU have been received, the receiving device can concatenate these one or more received SLC PDUs into a single SLC SDU in ascending order of their frame sequence number field values. Furthermore, the receiving device can send feedback information (e.g., a first ACK) to the transmitting device. Upon receiving the feedback information, the transmitting device can confirm that the receiving device has received all SLC PDUs.

[0195] If it is determined that not all SLC PDUs in an SLC SDU have been received, the receiving device can send feedback information (e.g., a second ACK) to notify the sending device to retransmit the unreceived SLC PDUs after the SLC layer reception window ends. After splicing the SLC SDUs, the receiving device can report the SLC SDUs to the MDCP layer through the inter-layer interface as MDCP PDUs.

[0196] In this system, the receiving device can control the transmission strategy of feedback information (e.g., ACK) and the splicing of SLCPDUs at the SLC layer via the SLC layer receive state controller, based on the SAI field in the SLC PDU. The duration of this SLC layer receive state controller is the maximum retransmission time of the SLC PDU on the transmitting device.

[0197] For example, if the receiving device receives the following SLC PDUs: 1st SLC PDU with SAI value "0", total frame count "11", and frame sequence number "00"; 2nd SLC PDU with SAI value "0", total frame count "11", and frame sequence number "01"; 3rd SLC PDU with SAI value "0", total frame count "11", and frame sequence number "10"; 4th SLC PDU with SAI value "0", total frame count "11", and frame sequence number "11", the receiving device determines that it has received all SLCPDUs from the first SLC SDU (SLCSDU0). The receiving device can then concatenate these four SLC PDUs in ascending order of frame sequence number to form SLCSDU0 and report it to the MDCP layer as MDCP PDU0. The receiving device can then store MDCP PDU0 in the MDCP layer receive buffer (MDCPRxbuffer). In MDCP PDU0, the value of the successor indicator field is "01".

[0198] Furthermore, the SLC layer receive status controller of the receiving device can send an ACK to the SLC layer transmit status controller of the transmitting device.

[0199] In one possible implementation, the ACK frame may include a frame header and a bitmap field. The bitmap field can be used to provide feedback on the reception status of the SLC PDUs of the receiving device. For example, the bitmap field can be 1 bit long, and its value can indicate whether all SLCPDUs of the SLCSDU have been received. For instance, a bitmap field value of 0 indicates that none of the SLCPDUs of the SLCSDU have been received, while a bitmap field value of 1 indicates that all SLCPDUs of the SLCSDU have been received. This example is merely for illustrative purposes and should not be construed as limiting the scope of the application.

[0200] For example, the bitmap field can be 4 bits long, and each bit in the bitmap can indicate whether the corresponding SLCPDU with the frame number has been received. Specifically, the first bit of the bitmap can be used to indicate the reception status of the first SLCPDU (e.g., frame number 00), the second bit can be used to indicate the reception status of the second SLCPDU (e.g., frame number 01), and so on. When the value of a bit in the bitmap is 0, it indicates that the receiving device has not received the SLCPDU corresponding to that bit within the receiving window. When the value of a bit in the bitmap is 1, it indicates that the receiving device has received the SLCPDU corresponding to that bit within the receiving window.

[0201] Here, since the receiving device has received all SLCPDUs of SLCSDU0, the bitmap value is 1111. When the transmitting device receives the first ACK sent by the receiving device, based on the bitmap value of the first ACK, it confirms that the receiving device has successfully received all SLCPDUs of SLCPDU0 and begins sending SLCSDU1.

[0202] For example, if the receiving device receives a first SLC PDU with a SAI value of "0", a total frame count of "11", and a frame sequence number of "00", a second SLC PDU with a SAI value of "0", a total frame count of "11", and a frame sequence number of "10", and a third SLCPDU with a SAI value of "0", a total frame count of "11", and a frame sequence number of "11", and the receiving device does not receive an SLCPDU0 with a SAI value of "0", a total frame count of "11", and a frame sequence number of "01" within the receiving window time (that is, the second SLCPDU (frame sequence number 01) among all SLCPDUs that did not receive SLCSDU0), the receiving device's SLC layer receive state controller can send a second ACK to the transmitting device's SLC layer transmit state controller. The bitmap field of the second ACK has a value of 1011. When the transmitting device receives the second ACK sent by the receiving device, it confirms, based on the bitmap value, that the receiving device has not received the second SLCPDU of SLCPDU0, and the transmitting device retransmits the second SLCPDU of SLCPDU0.

[0203] 4. The protocol parsing process of the receiving device for the received data at the MDCP layer.

[0204] At the MDCP layer, after receiving all MDCP PDUs of an MDCP SDU sent by the transmitting device, the receiving device can aggregate multiple MDCP PDUs according to the receiving time order based on the successor indication field in the MDCP PDU to obtain an MDCPSDU.

[0205] For example, when the receiving device obtains an MDCP PDU with a successor indication field value of "11" from the SLC layer, it can retrieve all MDCP PDUs from the MDCP Rxbuffer and concatenate them according to the successor indication field value and the reception time order to obtain an MDCP SDU. The receiving device can then report the MDCP SDU to the application layer through the inter-layer interface as an application layer message.

[0206] It should be noted that during the inbound process, after the receiving device splices the data according to the values ​​of the subsequent indication fields and the order of the receiving time, it also needs to remove redundant indication fields and padding data to obtain the MDCP SDU.

[0207] In this way, the sending and receiving devices can ensure that no data is lost at the SLC layer through ACK.

[0208] However, if only the SLC layer acknowledgment mechanism is used, the sending device determines whether the receiving device's SLC layer has successfully received all SLC PDUs of the application layer message sent by the sending device based on the ACK, but this does not mean that the receiving device's application layer can successfully parse the received application layer message. Thus, it cannot reliably indicate whether the receiving device can obtain the original data sent by the sending device (i.e., the receiving device cannot parse the original data of the application layer message).

[0209] In other words, if the sending device successfully transmits data to the receiving device at the SLC layer, but the application layer decryption or decoding fails, the receiving device cannot parse the original data of the application layer message, and the sending device cannot confirm the receiving device's parsing status. This results in a situation where the user of the sending device believes they have successfully sent a BeiDou SMS message to the receiving device, but the receiving device cannot obtain the original data of successful reception. Moreover, even if the receiving device cannot obtain the original data, the operator still charges the user's communication fees based on the SLC layer's confirmation of successful application layer message transmission / reception, which is unreasonable and leads to a poor user experience.

[0210] Furthermore, in some emergency situations, relying solely on SLC layer confirmation can have serious consequences. For example, when terminal 100 sends emergency rescue information to BeiDou network device 200, if confirmation is only performed at the SLC layer and application layer decryption / decryption fails, the user of terminal 100 will be unaware and will not send a second emergency rescue message. BeiDou network device 200 will be unable to decode / decrypt the received application layer message and will be unable to send the rescue information in the application layer message to the National Emergency Rescue Center 27, thus delaying rescue time.

[0211] Therefore, this application provides an application layer receipt transmission method in a BeiDou communication system. After receiving an application layer message sent by a transmitting device, the receiving device can parse the application layer message and obtain the corresponding application layer receipt information based on the parsing result. The receiving device can send the application layer receipt information to the transmitting device, which can then confirm the parsing status of the application layer message by the receiving device (e.g., successful parsing or parsing failure). Using the method provided in this application embodiment, a reliable message transmission mechanism can be established, ensuring that the transmitting device can obtain information about the parsing status of the application layer message by the receiving device.

[0212] Furthermore, the transmitting device can also perform corresponding operations based on the application layer acknowledgment information. For example, if the application layer acknowledgment information indicates that the receiving device has successfully parsed the application layer message, the transmitting device ends the transmission operation. If the application layer acknowledgment information indicates that the receiving device has failed to parsing the application layer message, the transmitting device can retransmit the application layer message. In this way, the transmission reliability of the BeiDou communication system can be further guaranteed.

[0213] The following section details the transmission process of the application layer receipt transmission method in the BeiDou communication system.

[0214] like Figure 6A As shown, during the inbound process, terminal 100 sends data to BeiDou network device 200. Specifically, terminal 100 can send inbound data to BeiDou ground transceiver station 22. BeiDou ground transceiver station 22 can perform physical layer processing on the inbound data (e.g., despreading, demodulation, pilot removal, decoding, etc.) to obtain user frames, and send the user frames to BeiDou central station 23. BeiDou central station 23 can use the user frames as SLCPDUs and aggregate the SLCPDUs into application layer messages and report them to BeiDou short message fusion communication platform 24. After receiving the SLCPDU sent by terminal 100, BeiDou central station 23 can return an SLC layer acknowledgment character (ACK) to terminal 100. This ACK can be used to indicate whether BeiDou network device 200 has successfully received the SLCPDU sent by terminal 100. BeiDou short message fusion communication platform 24 can parse the received application layer messages to obtain application layer parsing information. This application layer parsing information can be used to indicate whether BeiDou network device 200 has successfully parsed the application layer messages sent by terminal 100.

[0215] like Figure 6B As shown, during the outbound process, the BeiDou network device 200 sends data to the terminal 100. Specifically, the BeiDou short message fusion communication platform 24 sends application layer messages to the BeiDou central station 23. The BeiDou central station 23 can split the application layer messages into multiple user frames and send these user frames sequentially to the BeiDou ground transceiver station 22. The BeiDou ground transceiver station 22 can splice the user frames into physical frames and perform physical layer processing (e.g., encoding, pilot insertion, modulation, spreading, etc.) on the physical frames to obtain outbound data, which is then sent to the terminal 100. After receiving the outbound data sent by the BeiDou network device 200, the terminal 100 can perform physical layer processing (e.g., despreading, demodulation, pilot removal, decoding, etc.) on the outbound data to obtain physical frames. The terminal 100 can extract its user frames from the physical frames and upload them to the SLC layer as SLCPDUs. After receiving the SLCPDU, the terminal 100 can return an SLC layer ACK to the BeiDou network device 200. The ACK can be used to indicate the status of the terminal 100 receiving the SLCPDU sent by the BeiDou network device 200. The terminal 100 can also aggregate the received SLCPDUs into application layer messages and parse the resulting application layer messages. The terminal 100 can generate corresponding application layer acknowledgment information based on the result of parsing the application layer messages. This application layer acknowledgment information can be used to indicate whether the terminal 100 successfully parsed the application layer messages sent by the BeiDou network device 200.

[0216] The following section details a possible application layer receipt processing mechanism in the BeiDou communication system 10.

[0217] Figure 7 This application illustrates a possible application-layer receipt processing mechanism between the transmitting and receiving devices in an embodiment of this application.

[0218] like Figure 7 As shown, after receiving all SLCPDUs corresponding to the application layer messages sent by the sending device, the receiving device can send ACK and application layer acknowledgment information to the sending device. Specifically, the application layer acknowledgment processing flow is as follows:

[0219] S701, the sending device generates an application layer message.

[0220] At the APP layer, the sending device can encode and compress the raw data to obtain compressed data, then encrypt the compressed data to obtain encrypted data, and add message header information to the encrypted data to obtain the application layer message.

[0221] S702, the sending device sends application layer messages from the APP layer to the MDCP layer through the inter-layer interface.

[0222] S703, the sending device uses the application layer message as an MDCPSDU, and obtains M MDCPPDUs based on the MDCPSDU.

[0223] At the MDCP layer, the sending device can treat application layer packets as MDCPSDUs and split the MDCPSDU into M MDCPPDUs, where M is a positive integer. It should be noted that when the sending device is terminal 100, the sending device needs to add padding data and a redundancy length indicator field to the MDCPSDU. Then, the MDCPSDU with added padding data and redundancy length indicator field is split into M MDCPPDUs.

[0224] S704, the transmitting device sends the MDCPPDU from the MDCP layer to the SLC layer through the inter-layer interface.

[0225] S705, the transmitting device uses MDCPPDU as SLCSDU and frames SLCSDU into N SLCPDUs.

[0226] At the SLC layer, the transmitting device can use MDCPPDU as SLCSDU and frame SLCSDU into SLCPDU. For a detailed description, please refer to the above. Figure 5 The embodiments described herein will not be repeated here.

[0227] S706, the transmitting device sends the SLCPDU to the receiving device.

[0228] Specifically, the transmitting device can send SLCPDU from the SLC layer to the PHY layer through the inter-layer interface.

[0229] At the PHY layer, the transmitting device can perform physical layer processing (e.g., encoding, pilot insertion, modulation, spread spectrum, etc.) on the SLCPDU sent from the SLC layer before forwarding it to the receiving device. Here, when the transmitting device is terminal 100, a detailed description of the operations performed by the transmitting device at the PHY layer can be found above. Figure 2A In the embodiment described above, when the transmitting device is a BeiDou network device 200, a detailed description of the operations performed by the transmitting device at the PHY layer can be found in the above description. Figure 3A The embodiments described herein will not be repeated here.

[0230] After receiving data from the transmitting device at the PHY layer, the receiving device performs demodulation and decoding operations on the received data. Then, the receiving device can upload the data, after physical layer processing (e.g., despreading, demodulation, pilot removal, decoding), to the SLC layer as an SLC layer SLCPDU. For a detailed description of the operations performed by the receiving device at the PHY layer when the receiving device is a BeiDou network device 200, please refer to the above. Figure 2B The embodiment described above. When the receiving device is terminal 100, a detailed description of the operations performed by the receiving device at the PHY layer can be found above. Figure 3B The embodiments described herein will not be repeated here.

[0231] S707, the transmitting device sends the first ACK to the receiving device.

[0232] At the SLC layer, the receiving device can reply with an ACK to the sending device based on the frame header information of the SLCPDU.

[0233] If the receiving device determines, based on the frame header information, that all SLCPDUs for which SLCSDUs have not been received, the receiving device can send a second ACK to the transmitting device. The second ACK can indicate all SLCPDUs for which the receiving device has not received the SLCSDUs, and it can also indicate the frame sequence number of the unreceived SLCPDUs. After receiving the second ACK, the transmitting device can retransmit the unreceived SLCPDUs indicated by the second ACK to the receiving device.

[0234] If the receiving device determines, based on the frame header information, that it has received all SLCPDUs of the SLCSDU, it can send a first ACK to the transmitting device. The first ACK can be used to indicate that the receiving device has received all SLCPDUs of the SLCSDU. After receiving the first ACK, the transmitting device determines that the receiving device has received the SLCPDUs of the SLCSDU. The following embodiments are described assuming the receiving device has received all SLCPDUs of the SLCSDU.

[0235] It should be noted that if the SLCPDU sent by the transmitting device is not the last SLCSDU, the transmitting device can continue to send the SLCPDU of the next SLCSDU after receiving the first ACK.

[0236] If the transmitting device sends the SLCPDU of the last SLCSDU of the MDCPSDU, the transmitting device can wait for the receiving device to send application layer acknowledgment information. This is because the receiving device only needs to receive all SLCPDUs corresponding to the last SLCSDU before it can send a first ACK to the transmitting device indicating that all SLCPDUs have been received. The receiving device needs to concatenate all SLCPDUs corresponding to the MDCPSDU to obtain the application layer message before it can begin parsing the application layer message and reply with the corresponding application layer acknowledgment information based on the result of parsing the application layer message. Therefore, the time it takes for the transmitting device to receive the first ACK is shorter than the time it takes to receive the application layer acknowledgment information.

[0237] S708, the receiving device splices SLCPDU into SLCSDU.

[0238] For a detailed description of the receiving device splicing SLCPDU, please refer to [link / reference]. Figure 5 The embodiments shown are not described in detail here.

[0239] S709, the receiving device uploads SLCSDU from the SLC layer to the MDCP layer through the inter-layer interface.

[0240] In S710, the receiving device can use SLCSDU as MDCPPDU and obtain MDCPSDU based on MDCPPDU.

[0241] At the MDCP layer, the receiving device can determine all the MDCPPDUs received from the MDCPSDU based on the successor indication field, and then concatenate the MDCPPDUs into an MDCPSDU according to the receiving order.

[0242] S711, the receiving device uploads MDCPSDU from the MDCP layer to the APP layer through the inter-layer interface.

[0243] S712, the receiving device treats the MDCPSDU as an application layer message, parses the application layer message, and generates application layer receipt information based on the result of parsing the application layer message.

[0244] At the APP layer, the receiving device can treat MDCPSDU as an application layer message and parse it. After parsing the application layer message, the receiving device can generate corresponding application layer receipt information based on the parsing result.

[0245] Specifically, when the receiving device fails to parse an application layer message, it can generate an application layer receipt indicating the failure. Conversely, when the receiving device fails to parse an application layer message, it can generate an application layer receipt indicating successful parsing.

[0246] For example, application layer receipt information can be an error code. The error code can be 1 bit long. When the error code value is 0, it indicates that the receiving device failed to parse the application layer message. When the error code value is 1, it indicates that the receiving device successfully parsed the application layer message. It should be noted that the error code values ​​and their meanings here are for illustrative purposes only.

[0247] S713, the receiving device sends the application layer receipt information to the sending device.

[0248] The receiving device can encapsulate the application layer receipt information into a receipt frame and send the receipt frame to the sending device. For a detailed description of how the receiving device receives the receipt frame and the sending device receives the application layer receipt information, please refer to [link to relevant documentation]. Figure 9 , Figure 10 The illustrated embodiment. Alternatively, the receiving device can encapsulate the application layer receipt information into an application layer receipt message and send the application layer receipt message to the sending device. Detailed descriptions of how the receiving device obtains the application layer receipt message and how the sending device obtains the application layer receipt information can be found in the subsequent embodiments and will not be repeated here.

[0249] The sending device can determine the result of the receiving device parsing the application layer message based on the received application layer acknowledgment information at the APP layer.

[0250] Furthermore, the transmitting device can also perform corresponding operations based on the result of the receiving device parsing the application layer message in the application layer receipt information. For example, if the application layer receipt information indicates that the receiving device has successfully parsed the application layer message, the transmitting device ends the current transmission operation or sends the next application layer message. If the application layer receipt information indicates that the receiving device has failed to parsing the application layer message, the transmitting device can retransmit the application layer message. In this way, the transmission reliability of the BeiDou communication system can be further guaranteed.

[0251] In one possible implementation, the application layer receipt information can not only indicate whether the receiving device successfully parsed the application layer message, but also, when the receiving device fails to parse the message, indicate the reason for the failure. In this way, the sending device can obtain the result of whether the receiving device successfully parsed the application layer message, and the reason for the parsing failure, from the application layer receipt information.

[0252] Specifically, after parsing the application layer message, the receiving device can determine the encoding (also known as the error code) corresponding to the result of parsing the application layer message. The error code is the application layer acknowledgment information of the receiving device.

[0253] For example, the error code can be 4 bits long. An error code value of 0000 indicates that the receiving device successfully parsed the application layer message. An error code value of 0001 indicates that the receiving device failed to parsed the application layer message due to a decryption error. An error code value of 0010 indicates that the receiving device failed to parsed the application layer message due to a decoding error, and so on.

[0254] It should be noted that if the receiving device cannot decrypt the encrypted data to obtain the compressed data, it can determine that the result of parsing the application layer message is a decryption error. If the receiving device cannot decompress and decode the compressed data to obtain the original data, it can determine that the result of parsing the application layer message is a decoding error. If the receiving device successfully parses the application layer message to obtain the original data, it can determine that the parsing result of the application layer message is successful.

[0255] Specifically, the receiving device can parse application layer messages at the application layer, and after obtaining the result of parsing the application layer messages, it sends the corresponding error code to the SLC layer through the inter-layer interface. The receiving device can add frame header information to the header of the error code to obtain an SLC layer receipt frame (also known as an application layer receipt). The receipt frame includes application layer receipt information (i.e., the error code). The receiving device can then send the receipt frame to the sending device.

[0256] After receiving the acknowledgment frame, the sending device can determine the receiving device's parsing of the application layer message based on the error code in the acknowledgment frame.

[0257] Furthermore, after receiving the receipt frame, the sending device can also perform corresponding operations based on the error code in the receipt frame.

[0258] If the error code indicates that the receiving device has successfully parsed the application layer message, the sending device can end the sending operation.

[0259] If the error code indicates that the receiving device failed to parse the application layer message and the reason for the failure is a decryption error, the sending device can determine that the reason for the decryption error is that the sending device's key information and the receiving device's key information are different. After receiving the acknowledgment frame, the sending device can negotiate with the receiving device to update the key information (including the key and password book).

[0260] Specifically, the transmitting and receiving devices can negotiate a key through the cellular network equipment after returning to the cellular network. If, after negotiating the key information, the transmitting device's key information is changed to the receiving device's key information, the transmitting device can re-encrypt and compress the data based on the changed key information to obtain encrypted data. The transmitting device then sends an application layer message containing the encrypted data to the receiving device.

[0261] Alternatively, if the receiving device changes its key information to the sending device's key information after the sending and receiving devices have negotiated the key information, the receiving device can re-decrypt the encrypted data of the application layer message based on the changed key information.

[0262] If the error code indicates that the receiving device failed to parse the application layer message and the reason for the failure is a decoding error, the sending device can determine that the reason for the decoding error is that the encoding and compression algorithms of the sending device and the receiving device are different. The sending device and the receiving device can negotiate the encoding and compression algorithm.

[0263] Specifically, the transmitting and receiving devices can negotiate an encoding and encryption algorithm through the cellular network equipment after returning to the cellular network. If, after negotiation, the transmitting device's encoding and compression algorithm is changed to the receiving device's, the transmitting device can re-encode and compress the original data based on the modified algorithm to obtain compressed data. The transmitting device then encrypts the compressed data to obtain encrypted data, and finally sends an application layer message containing the encrypted data to the receiving device.

[0264] Alternatively, if the transmitting and receiving devices negotiate the encoding and compression algorithm, and the receiving device changes its encoding and compression algorithm to that of the transmitting device, the receiving device can re-decode the compressed data based on the changed encoding and compression algorithm.

[0265] In some embodiments, both the transmitting and receiving devices store codebooks containing the encoding and compression algorithms used by the transmitting and receiving devices. When the codebooks of the transmitting and receiving devices are the same, the receiving device can successfully decode the compressed data to obtain the original data. When the codebooks of the transmitting and receiving devices are different, the receiving device cannot decode the compressed data to obtain the original data.

[0266] In one possible implementation, the sending device can display prompt message 1 when it determines, based on the application layer acknowledgment information, that the receiving device has successfully parsed the application layer message. Prompt message 1 can be used to indicate that the message was sent successfully. The sending device can also display prompt message 2 when it determines, based on the application layer acknowledgment information, that the receiving device has failed to parsing the application layer message. Prompt message 2 can be used to indicate that the message was not sent successfully.

[0267] Optionally, when the sending device determines, based on the application layer receipt information, that the receiving device failed to parse the application layer message and the reason for the failure is decryption failure, it can display prompt message 3. Prompt message 3 can be used to indicate that the message transmission failed due to an incorrect key. Furthermore, prompt message 3 can prompt the user of the sending device to return to the cellular network to update the key before sending the BeiDou short message again.

[0268] When the sending device determines, based on application layer receipt information, that the receiving device failed to parse the application layer message and the reason for the failure is decoding failure, it can display prompt message 4. Prompt message 4 can be used to indicate that the message transmission failed due to an error in the encoding and encryption algorithm. Furthermore, prompt message 3 can prompt the user of the sending device to return to the cellular network to update the encoding and encryption method before sending the BeiDou short message again.

[0269] In one possible implementation, the receiving device may be pre-configured to only reply with an SLC-level ACK after receiving all SLCPDUs of the last SLC SDU corresponding to the application-layer message from the sending device. Alternatively, the receiving device may be pre-configured to reply with both an SLC-level ACK and an application-layer acknowledgment message. Or, the receiving device may be pre-configured to only reply with an application-layer acknowledgment message.

[0270] In one possible implementation, the transmitting device can add a receipt indication field to the header of the application layer message. The transmitting device can use this field to indicate to the receiving device whether to reply with application layer receipt information. In this way, the BeiDou communication system can ensure transmission reliability when confirmation of the receiving device's parsing result of the application layer message is required. When confirmation of the receiving device's parsing result is not required, air interface resources are saved.

[0271] For example, at the APP layer, the sending device can encode, compress, and encrypt the raw data to obtain encrypted data. Then, it adds a header to the encrypted data to obtain an application-layer message. The specific format of the application-layer message can be found in [reference needed]. Figure 8 .

[0272] For example, Figure 8 An example of an application-layer message sent by a device is shown. Figure 8 The example application layer message shown illustrates this. An application layer message consists of a header and encrypted data. The decrypted data can be obtained by compressing and encrypting the original data. The header information may include, but is not limited to, a receipt indication field, an encryption indication field, and a compression indication field. Detailed descriptions of the encryption and compression indication fields can be found above. Figure 2A The aforementioned embodiments will not be described in detail here. The receipt indication field can be used to indicate whether it is necessary to receive application-layer receipt information from the device.

[0273] For example, the length of the receipt indication field can be 1 bit. When the value of the receipt indication field is 0, it can be used to indicate that the receiving device will not reply with application layer receipt information. When the value of the receipt indication field is 1, it can be used to indicate that the receiving device will reply with application layer receipt information.

[0274] At the MDCP layer, the sending device can use the application layer messages received from the APP layer as MDCPSDUs. The sending device can then divide the MDCPSDU into one or more fixed-length MDCP segments. The sending device can add a successor indicator field to the header of each MDCP segment to obtain an MDCP PDU. The successor indicator field indicates the order of the current MDCPPDU within the same MDCPSDU. It should be noted that when the sending device is terminal 100, the sending device can add padding data and a redundancy length indicator field to the MDCPSDU, and then divide the MDCPSDU with added padding data and redundancy length indicator fields into one or more fixed-length MDCP segments.

[0275] At the SLC layer, the transmitting device can frame MDCPPDU as SLCSDU into SLCPDU.

[0276] At the PHY layer, the transmitting device can perform physical layer processing on the SLCPDU (e.g., encoding, pilot insertion, modulation, spread spectrum, etc.) to obtain physical frames, and then send the physical frames to the receiving device.

[0277] At the PHY layer, the receiving device can perform physical layer processing (e.g., despreading, demodulation, depiloting, decoding, etc.) on the received physical frame before uploading it to the SLC layer.

[0278] At the SLC layer, the receiving device can send an ACK to the transmitting device based on the received SLCPDU. After receiving all SLCPDUs corresponding to the SLCSDU, the receiving device can frame the SLCPDUs to obtain the SLCSDU. The specific process of the receiving device sending an ACK can be found in the above embodiment, and will not be repeated here.

[0279] The receiving device can upload SLCSDU to the MDCP layer as MDCPPDU. After determining all received MDCPPDU based on the successor indication field, the receiving device can concatenate the MDCPPDU into an MDCPSDU according to the receiving order and upload the MDCPSDU to the APP layer.

[0280] At the APP layer, the receiving device can treat MDCPSDU as an application layer message and parse it. First, the receiving device can determine whether to reply with application layer acknowledgment information based on the acknowledgment indication field. If the receiving device determines that it will not reply with application layer acknowledgment information based on the acknowledgment indication field, the receiving device directly parses the application layer message.

[0281] If the receiving device determines that an application layer receipt is needed based on the receipt indication field, it can generate the corresponding application layer receipt based on the parsing result of the application layer message. After generating the application layer receipt, the receiving device can send it to the sending device.

[0282] In some possible embodiments, the receiving device can parse the receipt indication field at the MDCP layer and determine whether to reply with application-layer receipt information based on the value of the receipt indication field. It should be noted that, in the following embodiment description, the application-layer receipt information can be encapsulated into a receipt frame at the SLC layer. That is, the receipt indication field indicating whether the receiving device should reply with application-layer receipt information can be described as the receipt indication field indicating whether the receiving device should reply with a receipt frame.

[0283] For example, after determining all received MDCPPDUs based on the successor indication field, the receiving device can concatenate the MDCPPDUs into an MDCPSDU in the order they were received. Then, the receiving device can determine whether to reply with a receipt frame based on the receipt indication field.

[0284] When the receiving device determines that it will not reply with a receipt frame (e.g., the receipt indication field value is 0), the receiving device uploads the MDCPSDU to the APP layer. At the APP layer, the receiving device can treat the MDCPSDU as an application layer message and parse it.

[0285] When the receiving device detects a reply receipt frame (e.g., the receipt indication field value is 1), it can directly upload the MDCPSDU to the APP layer, treating the MDCPSDU as an application layer message and parsing it. The receiving device can also instruct the APP layer to generate application layer receipt information. After parsing the application layer message, the receiving device can generate corresponding application layer receipt information based on the parsing result. The receiving device can encapsulate the application layer receipt information into a receipt frame and send it to the sending device. The sending device can determine the result of the receiving device's parsing of the application layer message based on the application layer receipt information. Furthermore, the sending device can perform corresponding operations based on the application layer receipt information; for details, please refer to the above. Figure 7 The embodiments described herein will not be repeated here.

[0286] For details regarding the receipt frame when the receiving device is a BeiDou network device 200, please refer to [link / reference needed]. Figure 9 The embodiment described above.

[0287] The following is an example of a Beidou network device 200 sending a receipt frame, provided in an embodiment of this application.

[0288] like Figure 9 As shown, firstly, the BeiDou network device 200 can generate a receipt frame at the SLC layer. Specifically, the BeiDou network device 200 can send the application layer receipt information corresponding to the result of parsing the application layer message to the SLC layer. The application layer receipt information can be a notification message, and the BeiDou network device 200 can generate a receipt frame corresponding to the result of parsing the application layer message at the SLC layer based on the notification message.

[0289] Alternatively, the application layer receipt information can be an error code. At the SLC layer, the BeiDou network device 200 can write the application layer receipt frame information into the user information.

[0290] For example, the error code can be 4 bits long, and each error code corresponds to a result of parsing the application layer message.

[0291] For example, the meaning of some values ​​of an error code can be as follows:

[0292] 0000: Indicates that the BeiDou network device successfully resolved the application layer message.

[0293] 0001: Indicates that the Beidou network device 200 failed to parse the application layer message due to a decryption error.

[0294] 0010: Indicates that the Beidou network device 200 failed to parse the application layer message due to a decoding error.

[0295] Afterwards, the BeiDou network device 200 can add frame header information before the user information to obtain a receipt frame. The frame header information may include, but is not limited to, a start identifier field, a frame length field, a user identity (ID) field, and a frame type field.

[0296] The start identifier field can be used to identify the starting position of a new user frame of the Beidou network device 200.

[0297] The frame length field can be used to identify the length of a user frame.

[0298] The User ID field can be used to identify the device receiving the application layer receipt (e.g., terminal 100). Terminal 100 can retrieve the user frame belonging to terminal 100 from the outbound data based on the value of the User ID field.

[0299] The frame type field can be used to identify the type of user frame. For example, the frame type field can be 2 bits long. When the frame type field value is 00, it indicates that the current user frame is a general data frame. General data frames can be used to transmit raw data. When the frame type field value is 01, it indicates that the current user frame is an ACK frame. ACK frames can be used to confirm the transmission status of SLCPDUs at the SLC layer. When the frame type field value is 10, it indicates that the current user frame is a receipt frame. Receipt frames can be used to confirm the parsing status of application layer messages at the application layer. Here, the user frame sent by BeiDou network device 200 to terminal 100 is a receipt frame, therefore the frame type field value can be 10.

[0300] Subsequently, the BeiDou network device 200 can concatenate the receipt frame with other user frames and add a version number field to the header of multiple user frames. The version number field indicates the version of the BeiDou short message protocol. The BeiDou network device 100 can also add a checksum (e.g., a cyclic redundancy check (CRC) code) to the tail of multiple user frames to obtain a physical frame. The BeiDou network device 200 can perform physical layer processing on the physical frame (e.g., encoding, pilot insertion, modulation, spreading, etc.) and add a reserved segment to the physical frame to form the encoded data of the S2C-d branch, which is a fixed-length physical time slot. Then, the BeiDou network device 200 can synchronously send the encoded data of the S2C-d branch and the subcode of the S2C-p branch to the BeiDou short message satellite 21, which then relays it to one or more terminals (including terminal 100).

[0301] In this embodiment of the application, the above-mentioned receipt frame processing mechanism is only an example, and the specific operation of the receipt frame processing mechanism is not limited in this application.

[0302] Subsequently, terminal 100 can capture the encoded data of the S2C-d tributary based on the subcode of the S2C-p tributary sent by Beidou network device 200. After capturing the encoded data of the S2C-d tributary, terminal 100 can perform physical layer processing on the encoded data of the S2C-d tributary (e.g., despreading, demodulation, pilot removal, decoding, etc.) to obtain physical frames. Then, it can extract user frames from the physical frames whose user ID field value matches the user ID value of terminal 100.

[0303] When terminal 100 determines that the user frame type is a receipt frame based on the frame type field in the frame header information, terminal 100 can upload the error code in the receipt frame to the APP layer through the inter-layer interface at the SLC layer. At the APP layer, based on the error code in the user information, the result of BeiDou network device 200 parsing the application layer message is obtained. Furthermore, terminal 100 can perform corresponding operations based on different results. For a detailed description of the operations performed by terminal 100, please refer to [link to relevant documentation]. Figure 7 The embodiments described herein will not be repeated here.

[0304] When the receiving device is terminal 100, the detailed description of the receipt frame can be found in [link to relevant documentation]. Figure 10 The embodiment described above.

[0305] The following is an example of a terminal 100 sending a receipt frame provided in an embodiment of this application.

[0306] like Figure 10 As shown, firstly, terminal 100 can send the result of parsing the application layer message to the SLC layer. At the SLC layer, terminal 100 can write the application layer receipt information corresponding to the result of parsing the application layer message into the user information. The application layer receipt information can be an error code. Error codes can be used to indicate the result of terminal 100 parsing the application layer message; a detailed description of error codes can be found above. Figure 9 The embodiments described herein will not be repeated here.

[0307] Afterwards, terminal 100 can add frame header information before the user information to obtain a receipt frame. The frame header information may include, but is not limited to, a version number field, a subtype indicator field, a user ID field, a total number of frames field, a frame sequence number field, a SAI field, a reserved field (reserve, RSV), etc.

[0308] The textual descriptions of the SAI field, total frame count field, and frame sequence number field can be found above. Figure 2A The embodiments described herein will not be repeated here.

[0309] The version number field can be used to identify the version of the BeiDou short message protocol.

[0310] The subtype indicator field can be used to identify the type of user frame. For example, the length of the subtype indicator field can be 2 bits. When the value of the subtype indicator field is 00, it can identify the current user frame as a general data frame. General data frames can include, but are not limited to, emergency rescue frames, location report frames, message communication frames, etc. When the value of the subtype indicator field is 01, it can identify the current user frame as an ACK frame. When the value of the subtype indicator field is 10, it can identify the current user frame as a receipt frame. Here, the BeiDou network device 200 sends a receipt frame to the terminal 100, so the value of the subtype indicator field can be 10.

[0311] The User ID field can be used to identify the device (Terminal 100) that receives the application layer receipt.

[0312] Among them, the reserved fields can be used for other fields in the subsequent BeiDou communication system, and there are no restrictions here.

[0313] Afterwards, terminal 100 can send the receipt frame to the PHY layer. At the PHY layer, terminal 100 can use the receipt frame as a data segment, and after adding a synchronization header and check bit to the data segment, send the corresponding physical frame to BeiDou short message satellite 21, which will then relay it to BeiDou network device 200.

[0314] After receiving a physical frame, the BeiDou network device 200 can process it at the physical layer (e.g., despreading, demodulation, pilot removal, decoding, etc.) to obtain a user frame and upload it to the SLC layer. At the SLC layer, the BeiDou network device 200 can determine if the user frame is a receipt frame based on the value of the subtype indicator field. Then, the BeiDou network device 200 can upload the error code of the receipt frame to the APP layer via the inter-layer interface. At the APP layer, the BeiDou network device 200 can obtain the result of the terminal 100 parsing the application layer message based on the error code of the receipt frame.

[0315] Furthermore, the BeiDou network device 200 can also perform corresponding operations based on the results of the application layer message parsing by the terminal 100. For details, please refer to the above. Figure 7 The embodiments described herein will not be repeated here.

[0316] In the embodiments of this application, the above-described receipt frame processing mechanism is only an example, and this application does not limit the specific operation of the receipt frame processing mechanism.

[0317] In one possible implementation, the receiving device can encapsulate the application layer receipt information into an application layer receipt message at the APP layer. Then, the receiving device can send the application layer receipt message to the sending device. This way, the application layer receipt message can be obtained using the existing application layer message sending mechanism, reducing the need for changes to the processing mechanism of the BeiDou communication system.

[0318] Specifically, the receiving device can use the application layer receipt information as the aforementioned raw data. First, the receiving device can encode and compress the application layer receipt information to obtain compressed data. Then, it can encrypt the compressed data to obtain encrypted data. Afterward, the receiving device can add message header information before the encrypted data to obtain the application layer receipt message.

[0319] The message header information may include, but is not limited to, an encryption indicator field, a compression indicator field, and a receipt identifier field. For descriptions of the encryption indicator field and the compression indicator field, please refer to the above. Figure 3A The embodiments described herein will not be repeated here. The receipt identifier field can be used to indicate whether the application layer message includes application layer receipt information.

[0320] For example, the length of the receipt identifier field can be 1 bit. When the value of the receipt identifier field is 1, the application layer message includes application layer receipt information. It should be noted that an application layer message that includes application layer receipt information can be simply referred to as an application layer receipt message. When the value of the receipt identifier field is 0, the application layer message does not include application layer receipt information.

[0321] It should be noted that the process of the receiving device generating an application layer receipt message and sending it to the sending device is the same as the process of the sending device generating and sending application layer messages. For a detailed textual description, please refer to the above. Figure 2A or Figure 3A The embodiments described above will not be repeated here. The process by which the sending device obtains the raw data of the application layer acknowledgment message is the same as the process by which the receiving device obtains the raw data of the application layer message described above. For a detailed textual description, please refer to the above. Figure 2B or Figure 3B The embodiment described above.

[0322] After receiving an application layer message, the sending device can determine whether the application layer message is an application layer receipt message based on the value of the receipt identifier field. When the sending device determines that the receipt identifier field indicates that the application layer message is an application layer receipt message, the sending device can determine the result of the receiving device parsing the application layer message based on the original data (i.e., application layer receipt information). For a detailed description, please refer to the above. Figure 7 The embodiments shown are not described in detail here.

[0323] Optionally, the receiving device can avoid compressing and encrypting the raw data, and directly add a message header before the application layer receipt information to obtain the application layer receipt message. Specifically, the receiving device can set the value of the compression indicator field in the message header to not use a compression algorithm, and can also set the value of the encryption indicator field in the message header to not use an encryption algorithm.

[0324] Alternatively, the header information of the application layer receipt message may exclude the compression indication field and the encryption indication field.

[0325] The following section details an application-layer receipt processing mechanism in the BeiDou communication system 10.

[0326] Figure 11 This illustrates another possible application-layer receipt processing mechanism between the transmitting and receiving devices in an embodiment of this application.

[0327] like Figure 11 As shown, after receiving the SLCPDU of the last SLCSDU corresponding to the application layer message sent by the sending device, the receiving device may not send an SLC layer ACK, but only send application layer acknowledgment information to the sending device. In this way, when the sending device receives the application layer acknowledgment information, it can prove that the receiving device has received all SLCPDUs of the SLCSDU, and the receiving device does not need to send an ACK for the last SLCSDU's SLCPDU, thus saving the receiving device's air interface resources.

[0328] S1101, The sending device generates an application layer message.

[0329] S1102, the sending device sends the application layer message from the APP layer to the MDCP layer through the inter-layer interface.

[0330] S1103, the sending device uses the application layer message as an MDCPSDU, and obtains M MDCPPDUs based on the MDCPSDU.

[0331] S1104, the transmitting device sends the MDCPPDU from the MDCP layer to the SLC layer through the inter-layer interface.

[0332] S1105, the transmitting device uses the MDCPPDU as an SLCSDU and frames the SLCSDU into N SLCPDUs.

[0333] S1106, the transmitting device sends the SLCPDU to the receiving device.

[0334] For a detailed description of steps S1101 to S1106, please refer to the above. Figure 7 The embodiments described herein will not be repeated here.

[0335] S1107, the receiving device splices the SLCPDU into an SLCSDU.

[0336] S1108, the receiving device uploads SLCSDU from the SLC layer to the MDCP layer through the inter-layer interface.

[0337] S1109, the receiving device can use SLCSDU as MDCPPDU and obtain MDCPSDU based on MDCPPDU.

[0338] S1110, the receiving device can upload MDCPSDU from the MDCP layer to the APP layer through the inter-layer interface.

[0339] At the SLC layer, after receiving an SLCPDU (SLCSDU), the receiving device can reply with an ACK to the transmitting device based on the SLCPDU's frame header information. If the receiving device determines, based on the frame header information, that all SLCPDUs for which the SLCSDU has not been received, it can send a second ACK to the transmitting device. The second ACK can indicate all SLCPDUs for which the receiving device has not received the SLCSDU, and it can also indicate the frame sequence number of the unreceived SLCPDUs. After receiving the second ACK, the transmitting device can retransmit the unreceived SLCPDUs indicated by the second ACK to the receiving device.

[0340] If the receiving device determines that it has received all SLCPDUs based on the frame header information, the receiving device can splice the SLCPDUs to obtain an SLCSDU and upload the SLCSDU to the MDCP layer.

[0341] At the MDCP layer, the receiving device can treat SLCSDU as MDCPPDU. The receiving device can determine whether the current MDCPPDU is the last MDCPPDU in the MDCPSDU hierarchy based on the successor indication field of the MDCPPDU.

[0342] If the receiving device determines, based on the successor indication field, that the currently received MDCPPDU is not the last MDCPPDU among all MDCPPDUs of the MDCPSDU, the receiving device can send the first ACK at the SLC layer. After receiving the first ACK, the transmitting device can send the next MDCPPDU of the MDCPSDU to the receiving device.

[0343] The receiving device can send a first message from the MDCP layer to the SLC layer. The first message can be used to instruct the receiving device to send a first ACK to the sending device at the SLC layer.

[0344] If the receiving device determines, based on the successor indication field, that the currently received MDCPPDU is the last MDCPPDU among all MDCPPDUs of MDCPSDU, the receiving device can concatenate the MDCPPDUs into an MDCPSDU according to the receiving order and upload the MDCPSDU to the APP layer.

[0345] It should be noted that after the receiving device determines, based on the successor indication field, that the currently received MDCPPDU is the last MDCPPDU among all MDCPPDUs of the MDCPSDU, it does not send the first ACK at the SLC layer. The first ACK is used to indicate that the receiving device has received all SLCPDUs of the currently sent SLCSDU at the SLC layer.

[0346] S1111, the receiving device treats MDCPSUD as an application layer message, parses the application layer message, and generates application layer receipt information based on the result of parsing the application layer message.

[0347] At the APP layer, the receiving device can treat MDCPSDU as an application layer message and parse it. After parsing the application layer message, the receiving device can generate corresponding application layer receipt information based on the parsing result. Specifically, when the receiving device is a BeiDou network device 200, a detailed description of the application layer receipt information generation process can be found above. Figure 9 In the aforementioned embodiment, when the receiving device is terminal 100, a detailed description of the application layer receipt information generated by the receiving device can be found above. Figure 10 The embodiments described herein will not be repeated here.

[0348] Here, the application layer receipt information can be used not only to indicate the status of the receiving device parsing the application layer message, but also to indicate that the receiving device has received all SLCPDUs of the last SLCSDU at the SLC layer.

[0349] S1112, the receiving device sends the application layer receipt information to the sending device.

[0350] Specifically, the process by which the sending device receives application layer acknowledgment information can be found above. Figures 9 to 10 The embodiments shown are not described in detail here.

[0351] After receiving the application layer acknowledgment information, the sending device can determine the result of the receiving device parsing the application layer message based on the application layer acknowledgment information. Furthermore, the sending device can perform corresponding operations based on the application layer acknowledgment information; for details, please refer to the above description. Figure 7 The embodiments described herein will not be repeated here.

[0352] In one possible implementation, the sending device can indicate to the receiving device whether to send an application-layer acknowledgment by adding an acknowledgment indication field to the message header. This allows the sending device to decide whether to send an application-layer acknowledgment, saving the receiving device time in cases where an application-layer acknowledgment is not required.

[0353] In other words, at the APP layer, when the receiving device determines that it will not reply with application layer acknowledgment information (e.g., the acknowledgment indication field value is 0), the receiving device sends the first ACK to the sending device at the SLC layer. When the receiving device determines that it will reply with application layer acknowledgment information (e.g., the acknowledgment indication field value is 0), the receiving device can parse the original data of the application layer message, generate application layer acknowledgment information based on the result of parsing the application layer message, and then send the application layer acknowledgment information to the sending device.

[0354] In one possible implementation, when the receiving device determines whether to reply with application-layer acknowledgment information based on the acknowledgment indication field, the receiving device can parse the acknowledgment indication field at the MDCP layer and determine whether to reply with application-layer acknowledgment information based on the value of the acknowledgment indication field. In this way, the sending device can determine the receiving device's SLC layer reception status and the receiving device's parsing of application-layer messages solely through the application-layer acknowledgment information. Furthermore, since the receiving device only replies with application-layer acknowledgment information, it can also save resources used by the receiving device to send ACK frames.

[0355] For example, at the SLC layer, the receiving device can reply with an ACK based on the frame header information of the SLCPDU after receiving the SLCPDU sent by the transmitting device.

[0356] If the receiving device determines, based on the frame header information, that all SLCPDUs for which SLCSDUs have not been received, the receiving device can send a second ACK to the transmitting device. The second ACK can indicate all SLCPDUs for which the receiving device has not received the SLCSDUs, and it can also indicate the frame sequence number of the unreceived SLCPDUs. After receiving the second ACK, the transmitting device can retransmit the unreceived SLCPDUs indicated by the second ACK to the receiving device.

[0357] If the receiving device determines that it has received all SLCPDUs based on the frame header information, the receiving device can splice the SLCPDUs to obtain an SLCSDU and upload the SLCSDU to the MDCP layer as an MDCPPDU.

[0358] At the MDCP layer, the receiving device can determine whether the current MDCPPDU is the last MDCPPDU in the MDCPSDU series based on the successor indication field of the MDCPPDU.

[0359] If the receiving device determines, based on the successor indication field, that the currently received MDCPPDU is not the last MDCPPDU among all MDCPPDUs of the MDCPSDU, the receiving device can notify the SLC layer to send the first ACK. After receiving the first ACK, the transmitting device can send the next MDCPPDU of the MDCPSDU to the receiving device.

[0360] If the receiving device determines, based on the successor indication field, that the currently received MDCPPDU is the last MDCPPDU among all MDCPPDUs in the MDCPSDU sequence, the receiving device can concatenate the MDCPPDUs in the receiving order to obtain the MDCPSDU. It should be noted that when the receiving device is a BeiDou network device 200, the BeiDou network device 200 can remove the padding data from the concatenated MDCPPDU based on the redundancy length indication field to obtain the MDCPSDU.

[0361] At the MDCP layer, the receiving device can determine whether to reply with application layer receipt information to the sending device based on the receipt indication field.

[0362] When the receiving device determines that it will not respond with application layer acknowledgment information (e.g., the acknowledgment indication field value is 0), the receiving device notifies the SLC layer to send the first ACK to the sending device and uploads the MDCPSDU to the APP layer. At the APP layer, the receiving device can treat the MDCPSDU as an application layer message and parse it.

[0363] When the receiving device determines that an application layer acknowledgment message has been received (e.g., the acknowledgment indication field value is 0), the receiving device directly uploads the MDCPSDU to the APP layer and parses the MDCPSDU as an application layer message. Simultaneously, the receiving device can notify the APP layer to provide application layer acknowledgment information. The receiving device can generate corresponding application layer acknowledgment information based on the result of parsing the application layer message. The receiving device can then send the application layer acknowledgment information to the sending device. For a detailed description of the generation of application layer acknowledgment information by the receiving device when the receiving device is a BeiDou network device 200, please refer to the above. Figure 9 In the aforementioned embodiment, when the receiving device is terminal 100, a detailed description of the application layer receipt information generated by the receiving device can be found above. Figure 10 The embodiments described herein will not be repeated here.

[0364] After receiving the application layer acknowledgment information, the sending device can determine the result of the receiving device parsing the application layer message based on the application layer acknowledgment information. Here, the application layer acknowledgment information can also be equivalent to the first ACK, allowing the sending device to confirm, based on the application layer acknowledgment information, all SLCPDUs corresponding to the last MDCPPDU of the MDCPSDU received by the receiving device.

[0365] In some possible embodiments, the receiving device may be pre-configured to reply with application-layer receipt information to the sending device. In this way, the receiving device automatically replies with application-layer receipt information without needing to rely on the receipt indication field.

[0366] The terminal 100 provided in the embodiments of this application is described below.

[0367] Terminal 100 may be a mobile phone, tablet computer, desktop computer, laptop computer, handheld computer, notebook computer, ultra-mobile personal computer (UMPC), netbook, as well as cellular phone, personal digital assistant (PDA), augmented reality (AR) device, virtual reality (VR) device, artificial intelligence (AI) device, wearable device, in-vehicle device, smart home device and / or smart city device. The specific type of electronic device is not particularly limited in the embodiments of this application.

[0368] Figure 12 A schematic diagram of a hardware structure provided in an embodiment of this application is shown.

[0369] The following description uses terminal 100 as an example to illustrate the embodiment. It should be understood that... Figure 12 The terminal 100 shown is merely an example, and terminal 100 can have more than... Figure 12 The more or fewer components shown can be combined into two or more components, or they can have different component configurations. Figure 12 The various components shown 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.

[0370] Terminal 100 may include: processor 110, external memory interface 120, internal memory 121, universal serial bus (USB) interface 130, charging management module 140, power management module 141, battery 142, antenna 1, antenna 2, mobile communication module 150, wireless communication module 160, audio module 170, speaker 170A, receiver 170B, microphone 170C, headphone jack 170D, sensor module 180, button 190, motor 191, indicator 192, camera 193, display screen 194, and subscriber identification module (SIM) card interface 195, etc. The sensor module 180 may include a pressure sensor 180A, a gyroscope sensor 180B, a barometric pressure sensor 180C, a magnetic sensor 180D, an accelerometer sensor 180E, a distance sensor 180F, a proximity 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.

[0371] It is understood that the structure illustrated in the embodiments of the present invention does not constitute a specific limitation on the terminal 100. In other embodiments of this application, the terminal 100 may include more or fewer components than illustrated, or combine some components, or split some components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0372] Processor 110 may include one or more processing units, such as: application processor (AP), modem processor, graphics processing unit (GPU), image signal processor (ISP), controller, memory, video codec, digital signal processor (DSP), baseband processor, and / or neural network processing unit (NPU), etc. Different processing units may be independent devices or integrated into one or more processors.

[0373] The controller can serve as the central nervous system and command center of the terminal 100. The controller can generate operation control signals based on the instruction opcode and timing signals to control the fetching and execution of instructions.

[0374] The processor 110 may also include a memory for storing instructions and data. In some embodiments, the memory in the processor 110 is a cache memory. This memory can store instructions or data that the processor 110 has just used or that are used repeatedly. If the processor 110 needs to use the instruction or data again, it can retrieve it directly from the memory. This avoids repeated accesses, reduces the waiting time of the processor 110, and thus improves the efficiency of the system.

[0375] In some embodiments, the processor 110 may include one or more interfaces. Interfaces may include an inter-integrated circuit (I2C) interface, an inter-integrated circuit sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a mobile industry processor interface (MIPI), a general-purpose input / output (GPIO) interface, a subscriber identity module (SIM) interface, and / or a universal serial bus (USB) interface, etc.

[0376] The I2C interface is a bidirectional synchronous serial bus, including a serial data line (SDA) and a serial clock line (SCL). In some embodiments, the processor 110 may include multiple I2C buses. The processor 110 can couple to the touch sensor 180K, charger, flash, camera 193, etc., through different I2C bus interfaces. For example, the processor 110 can couple to the touch sensor 180K through the I2C interface, enabling the processor 110 and the touch sensor 180K to communicate through the I2C bus interface, thereby realizing the touch function of the terminal 100.

[0377] The I2S interface can be used for audio communication. In some embodiments, the processor 110 may include multiple I2S buses. The processor 110 can be coupled to the audio module 170 via the I2S bus to enable communication between the processor 110 and the audio module 170. In some embodiments, the audio module 170 can transmit audio signals to the wireless communication module 160 via the I2S interface to enable the function of answering phone calls through a Bluetooth headset.

[0378] The PCM interface can also be used for audio communication, sampling, quantizing, and encoding analog signals. In some embodiments, the audio module 170 and the wireless communication module 160 can be coupled via the PCM bus interface. In some embodiments, the audio module 170 can also transmit audio signals to the wireless communication module 160 via the PCM interface, enabling the function of answering phone calls through a Bluetooth headset. Both the I2S interface and the PCM interface can be used for audio communication.

[0379] The UART interface is a universal serial data bus used for asynchronous communication. This bus can be a bidirectional communication bus. It converts the data to be transmitted between serial and parallel communication. In some embodiments, the UART interface is typically used to connect the processor 110 and the wireless communication module 160. For example, the processor 110 communicates with the Bluetooth module in the wireless communication module 160 via the UART interface to implement Bluetooth functionality. In some embodiments, the audio module 170 can transmit audio signals to the wireless communication module 160 via the UART interface to enable music playback through Bluetooth headphones.

[0380] The MIPI interface can be used to connect the processor 110 to peripheral devices such as the display screen 194 and the camera 193. The MIPI interface includes a camera serial interface (CSI) and a display serial interface (DSI). In some embodiments, the processor 110 and the camera 193 communicate via the CSI interface to enable the shooting function of the terminal 100. The processor 110 and the display screen 194 communicate via the DSI interface to enable the display function of the terminal 100.

[0381] The GPIO interface can be configured via software. It can be configured as a control signal or a data signal. In some embodiments, the GPIO interface can be used to connect the processor 110 to a camera 193, a display screen 194, a wireless communication module 160, an audio module 170, a 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.

[0382] USB port 130 is a USB standard compliant interface, specifically a Mini USB port, Micro USB port, USB Type-C port, etc. USB port 130 can be used to connect a charger to charge terminal 100, and can also be used for data transfer between terminal 100 and peripheral devices. It can also be used to connect headphones for audio playback. This interface can also be used to connect other electronic devices, such as AR devices.

[0383] It is understood that the interface connection relationships between the modules illustrated in the embodiments of the present invention are merely illustrative and do not constitute a structural limitation on the terminal 100. In other embodiments of this application, the terminal 100 may also adopt different interface connection methods or a combination of multiple interface connection methods as described in the above embodiments.

[0384] The charging management module 140 receives charging input from a charger. The charger can be a wireless charger or a wired charger. In some wired charging embodiments, the charging management module 140 receives charging input from the wired charger via the USB interface 130. In some wireless charging embodiments, the charging management module 140 receives wireless charging input via the wireless charging coil of the terminal 100. While charging the battery 142, the charging management module 140 can also supply power to the electronic device via the power management module 141.

[0385] The power management module 141 connects the battery 142, the charging management module 140, and the processor 110. The power management module 141 receives input from the battery 142 and / or the charging management module 140, providing power to the processor 110, internal memory 121, external memory, display screen 194, camera 193, and wireless communication module 160, etc. The power management module 141 can also monitor parameters such as battery capacity, battery cycle count, and battery health status (leakage current, impedance). In some other embodiments, the power management module 141 may also be located within the processor 110. In other embodiments, the power management module 141 and the charging management module 140 may be located in the same device.

[0386] The wireless communication function of terminal 100 can be implemented through antenna 1, antenna 2, mobile communication module 150, wireless communication module 160, modem processor and baseband processor, etc.

[0387] Antennas 1 and 2 are used to transmit and receive electromagnetic wave signals. Each antenna in terminal 100 can be used to cover one or more communication frequency bands. Different antennas can also be multiplexed to improve antenna utilization. For example, antenna 1 can be multiplexed as a diversity antenna for a wireless local area network. In some other embodiments, the antennas can be used in conjunction with tuning switches.

[0388] The mobile communication module 150 can provide solutions for wireless communication applications including 2G / 3G / 4G / 5G on the terminal 100. The mobile communication module 150 may include at least one filter, switch, power amplifier, low-noise amplifier (LNA), etc. The mobile communication module 150 can receive electromagnetic waves via the antenna 1, and perform filtering, amplification, and other processing on the received electromagnetic waves before transmitting them to the modem processor for demodulation. The mobile communication module 150 can also amplify the signal modulated by the modem processor and convert it into electromagnetic waves for radiation via the antenna 1. In some embodiments, at least some functional modules of the mobile communication module 150 may be housed in the processor 110. In some embodiments, at least some functional modules of the mobile communication module 150 and at least some modules of the processor 110 may be housed in the same device.

[0389] The modem processor may include a modulator and a demodulator. The modulator modulates the low-frequency baseband signal to be transmitted into a mid-to-high frequency signal. The demodulator demodulates the received electromagnetic wave signal into a low-frequency baseband signal. The demodulator then transmits the demodulated low-frequency baseband signal to the baseband processor for processing. After processing by the baseband processor, the low-frequency baseband signal is transmitted to the application processor. The application processor outputs sound signals through an audio device (not limited to speaker 170A, receiver 170B, etc.) or displays images or videos through the display screen 194. In some embodiments, the modem processor may be a separate device. In other embodiments, the modem processor may be independent of the processor 110 and may be housed in the same device as the mobile communication module 150 or other functional modules.

[0390] The wireless communication module 160 can provide solutions for wireless communication applications on the terminal 100, including wireless local area networks (WLAN) (such as wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite system (GNSS), satellite communication modules, frequency modulation (FM), near field communication (NFC), and infrared (IR) technologies. The wireless communication module 160 can be one or more devices integrating at least one communication processing module. The wireless communication module 160 receives electromagnetic waves via antenna 2, performs frequency modulation and filtering of the electromagnetic wave signals, and sends the processed signal to processor 110. The wireless communication module 160 can also receive signals to be transmitted from processor 110, perform frequency modulation and amplification, and convert them into electromagnetic waves for radiation via antenna 2.

[0391] Among them, the satellite communication module can be used to communicate with satellite network equipment. For example, in the BeiDou communication system, the satellite communication module can communicate with BeiDou network equipment 200, and the satellite communication module can support short message transmission between BeiDou network equipment 200.

[0392] In some embodiments, antenna 1 of terminal 100 is coupled to mobile communication module 150, and antenna 2 is coupled to wireless communication module 160, enabling terminal 100 to communicate with networks and other devices via wireless communication technology. The wireless communication technology may include Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (WCDMA), Time Division Code Division Multiple Access (TD-SCDMA), Long Term Evolution (LTE), BT, GNSS, WLAN, NFC, FM, and / or IR technologies, etc. The GNSS may include the Global Positioning System (GPS), the Global Navigation Satellite System (GLONASS), the BeiDou Navigation Satellite System (BDS), the Quasi-Zenith Satellite System (QZSS), and / or satellite-based augmentation systems (SBAS).

[0393] Terminal 100 implements display functions through a GPU, display screen 194, and application processor. The GPU is a microprocessor for image processing, connected to the display screen 194 and the application processor. The GPU is used to perform mathematical and geometric calculations and for graphics rendering. Processor 110 may include one or more GPUs, which execute program instructions to generate or modify display information.

[0394] Display screen 194 is used to display images, videos, etc. Display screen 194 includes a display panel. The display panel may be a liquid crystal display (LCD), an organic light-emitting diode (OLED), an active-matrix organic light-emitting diode (AMOLED), a flexible light-emitting diode (FLED), a miniature LED, a microLED, a quantum dot light-emitting diode (QLED), etc. In some embodiments, terminal 100 may include one or N displays 194, where N is a positive integer greater than 1.

[0395] Terminal 100 can perform shooting functions through ISP, camera 193, video codec, GPU, display 194 and application processor.

[0396] The ISP (Image Signal Processor) is used to process data fed back from the camera 193. For example, when taking a picture, the shutter is opened, and light is transmitted through the lens to the camera's photosensitive element. The light signal is converted into an electrical signal, and the camera's photosensitive element transmits the electrical signal to the ISP for processing, transforming it into an image visible to the naked eye. The ISP can also perform algorithmic optimization of image noise, brightness, and skin tone. The ISP can also optimize parameters such as exposure and color temperature of the shooting scene. In some embodiments, the ISP can be set in the camera 193.

[0397] Camera 193 is used to capture still images or videos. An object is projected onto a photosensitive element by generating an optical image through the lens. 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, which is then passed to an ISP for conversion into a digital image signal. The ISP outputs the digital image signal to a DSP for processing. The DSP converts the digital image signal into image signals in standard RGB, YUV, or other formats. In some embodiments, terminal 100 may include one or N cameras 193, where N is a positive integer greater than 1.

[0398] A digital signal processor (DSP) is used to process digital signals. Besides digital image signals, it can also process other digital signals. For example, when terminal 100 selects a frequency point, the DSP can perform Fourier transforms on the frequency energy.

[0399] Video codecs are used to compress or decompress digital video. Terminal 100 may support one or more video codecs. Thus, terminal 100 can play or record videos in various encoding formats, such as Moving Picture Experts Group (MPEG) 1, MPEG 2, MPEG 3, MPEG 4, etc.

[0400] NPU stands for Neural Network (NN) Computing Processor. By borrowing the structure of biological neural networks, such as the transmission patterns between neurons in the human brain, it can rapidly process input information and continuously learn on its own. NPUs can enable intelligent cognitive applications in terminals, such as image recognition, facial recognition, speech recognition, and text understanding.

[0401] The external storage interface 120 can be used to connect an external storage card, such as a Micro SD card, to expand the storage capacity of the terminal 100. The external storage card communicates with the processor 110 through the external storage interface 120 to perform data storage functions. For example, music, video, and other files can be saved on the external storage card.

[0402] Internal memory 121 can be used to store computer executable program code, which includes instructions. Processor 110 executes various functional applications and data processing of terminal 100 by running the instructions stored in internal memory 121. Internal memory 121 may include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function (such as sound playback, image playback, etc.), etc. The data storage area may store data created during the use of terminal 100 (such as audio data, phonebook, etc.). Furthermore, internal memory 121 may include high-speed random access memory and may also include non-volatile memory, such as at least one disk storage device, flash memory device, universal flash storage (UFS), etc.

[0403] Terminal 100 can implement audio functions, such as music playback and recording, through audio module 170, speaker 170A, receiver 170B, microphone 170C, headphone jack 170D, and application processor.

[0404] The audio module 170 is used to convert digital audio information into analog audio signals for output, and also to convert analog audio input into digital audio signals. The audio module 170 can also be used for encoding and decoding audio signals. In some embodiments, the audio module 170 may be located in the processor 110, or some functional modules of the audio module 170 may be located in the processor 110.

[0405] 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 make hands-free calls through the speaker 170A.

[0406] The receiver 170B, also known as the "earpiece," is used to convert audio electrical signals into sound signals. When the terminal 100 receives a phone call or voice message, the receiver 170B can be brought close to the listener's ear to hear the voice.

[0407] Microphone 170C, also known as a "microphone" or "voice transducer," is used to convert sound signals into electrical signals. When making a phone call or sending a voice message, the user can speak by bringing their mouth close to microphone 170C, inputting the sound signal into microphone 170C. Terminal 100 may have at least one microphone 170C. In some embodiments, terminal 100 may have two microphones 170C, which, in addition to collecting sound signals, can also perform noise reduction. In other embodiments, terminal 100 may have three, four, or more microphones 170C, which can collect sound signals, reduce noise, identify the sound source, and perform directional recording, etc.

[0408] The 170D headphone jack is used to connect wired headphones. The 170D headphone jack can be a USB 130 interface or a 3.5mm Open Mobile Terminal Platform (OMTP) standard interface, a CTIA (Cellular Telecommunications Industry Association of the USA) standard interface.

[0409] Pressure sensor 180A is used to sense pressure signals and convert them into electrical signals. In some embodiments, pressure sensor 180A can be disposed on display screen 194. There are many types of pressure sensors 180A, such as resistive pressure sensors, inductive pressure sensors, and capacitive pressure sensors. A capacitive pressure sensor may include at least two parallel plates with conductive material. When force is applied to pressure sensor 180A, the capacitance between the electrodes changes. Terminal 100 determines the pressure intensity based on the change in capacitance. When a touch operation is applied to display screen 194, terminal 100 detects the intensity of the touch operation based on pressure sensor 180A. Terminal 100 can also calculate the touch position based on the detection signal from pressure sensor 180A. In some embodiments, touch operations applied to the same touch position but with different touch operation intensities can correspond to different operation commands. For example: when a touch operation with an intensity less than a first pressure threshold is applied to the SMS application icon, a command to view an SMS is executed. When a touch operation with an intensity greater than or equal to the first pressure threshold is applied to the SMS application icon, a command to create a new SMS is executed.

[0410] The gyroscope sensor 180B can be used to determine the motion attitude of the terminal 100. In some embodiments, the gyroscope sensor 180B can determine the angular velocity of the terminal 100 around three axes (i.e., the x, y, and z axes). The gyroscope sensor 180B can be used for image stabilization. For example, when the shutter is pressed, the gyroscope sensor 180B detects the angle of the terminal 100's shake, calculates the distance that the lens module needs to compensate based on the angle, and allows the lens to counteract the shake of the terminal 100 through reverse movement, thus achieving image stabilization. The gyroscope sensor 180B can also be used in navigation and motion-sensing game scenarios.

[0411] The barometric pressure sensor 180C is used to measure air pressure. In some embodiments, the terminal 100 calculates altitude using the air pressure value measured by the barometric pressure sensor 180C to assist in positioning and navigation.

[0412] The magnetic sensor 180D includes a Hall sensor. The terminal 100 can use the magnetic sensor 180D to detect the opening and closing of the flip cover. In some embodiments, when the terminal 100 is a flip phone, the terminal 100 can detect the opening and closing of the flip cover using the magnetic sensor 180D. Then, based on the detected opening and closing state of the cover or the flip cover, features such as automatic flip unlocking can be set.

[0413] The 180E accelerometer can detect the magnitude of acceleration of terminal 100 in various directions (typically three axes). When terminal 100 is stationary, it can detect the magnitude and direction of gravity. It can also be used to identify the posture of electronic devices, and is applied to applications such as screen orientation switching and pedometers.

[0414] A distance sensor 180F is used to measure distance. The terminal 100 can measure distance via infrared or laser. In some embodiments, during a shooting scene, the terminal 100 can utilize the distance sensor 180F to measure distance for rapid focusing.

[0415] The proximity sensor 180G may include, for example, a light-emitting diode (LED) and a light detector, such as a photodiode. The LED may be an infrared LED. The terminal 100 emits infrared light outward through the LED. The terminal 100 uses the photodiode to detect infrared reflected light from nearby objects. When sufficient reflected light is detected, it can be determined that there is an object near the terminal 100. When insufficient reflected light is detected, the terminal 100 can determine that there is no object near the terminal 100. The terminal 100 may use the proximity sensor 180G to detect when a user holds the terminal 100 close to their ear for a call, so as to automatically turn off the screen to save power. The proximity sensor 180G can also be used in holster mode and pocket mode for automatic unlocking and screen locking.

[0416] The ambient light sensor 180L is used to sense the ambient light intensity. The terminal 100 can adaptively adjust the brightness of the display screen 194 based on the sensed ambient light intensity. The ambient light sensor 180L can also be used to automatically adjust the white balance when taking pictures. The ambient light sensor 180L can also work with the proximity sensor 180G to detect whether the terminal 100 is in a pocket to prevent accidental touches.

[0417] The fingerprint sensor 180H is used to collect fingerprints. The terminal 100 can use the characteristics of the collected fingerprints to unlock the device, access application locks, take photos with fingerprints, and answer calls with fingerprints.

[0418] Temperature sensor 180J is used to detect temperature. In some embodiments, terminal 100 uses the temperature detected by temperature sensor 180J to execute a temperature processing strategy. For example, when the temperature reported by temperature sensor 180J exceeds a threshold, terminal 100 reduces the performance of the processor located near temperature sensor 180J to reduce power consumption and implement thermal protection. In other embodiments, when the temperature is below another threshold, terminal 100 heats battery 142 to prevent abnormal shutdown of terminal 100 due to low temperature. In still other embodiments, when the temperature is below yet another threshold, terminal 100 boosts the output voltage of battery 142 to prevent abnormal shutdown due to low temperature.

[0419] Touch sensor 180K, also known as a "touch panel," can be located on display screen 194. The touch sensor 180K and display screen 194 together form a touchscreen, also known as a "touchscreen." Touch sensor 180K detects touch operations applied to or near it. The touch sensor can transmit the detected touch operation to the application processor to determine the type of touch event. Visual output related to the touch operation can be provided through display screen 194. In other embodiments, touch sensor 180K may also be located on the surface of terminal 100, in a different position than display screen 194.

[0420] The bone conduction sensor 180M can acquire vibration signals. In some embodiments, the bone conduction sensor 180M can acquire vibration signals from the vibrating bone segments of the human vocal cords. The bone conduction sensor 180M can also contact the human pulse to receive blood pressure signals. In some embodiments, the bone conduction sensor 180M can also be incorporated into headphones to form bone conduction headphones. The audio module 170 can parse the voice signals from the vibrating bone segments of the vocal cords acquired by the bone conduction sensor 180M to realize voice functionality. The application processor can parse heart rate information from the blood pressure signals acquired by the bone conduction sensor 180M to realize heart rate detection functionality.

[0421] Buttons 190 include a power button, volume buttons, etc. Buttons 190 can be mechanical buttons or touch-sensitive buttons. Terminal 100 can receive button input and generate key signal inputs related to user settings and function control of terminal 100.

[0422] Motor 191 can generate vibration alerts. Motor 191 can be used for incoming call vibration alerts or for touch vibration feedback. For example, different vibration feedback effects can correspond to touch operations performed on different applications (such as taking photos, playing audio, etc.). Motor 191 can also correspond to different vibration feedback effects for touch operations performed on different areas of the display screen 194. Different application scenarios (such as time reminders, receiving messages, alarm clocks, games, etc.) can also correspond to different vibration feedback effects. The touch vibration feedback effect can also be customized.

[0423] Indicator 192 can be an indicator light, used to indicate charging status, power changes, or to indicate messages, missed calls, notifications, etc.

[0424] The SIM card interface 195 is used to connect a SIM card. The SIM card can be inserted into or removed from the SIM card interface 195 to make contact with and separate from the terminal 100. The terminal 100 can support one or N SIM card interfaces, where N is a positive integer greater than 1. The SIM card interface 195 can support Nano SIM cards, Micro SIM cards, SIM cards, etc. Multiple cards can be inserted into the same SIM card interface 195 simultaneously. The multiple cards can be of the same or different types. The SIM card interface 195 is also compatible with different types of SIM cards. The SIM card interface 195 is also compatible with external memory cards. The terminal 100 interacts with the network through the SIM card to realize functions such as calls and data communication. In some embodiments, the terminal 100 uses an eSIM, i.e., an embedded SIM card. The eSIM card can be embedded in the terminal 100 and cannot be separated from the terminal 100.

[0425] The following describes an application layer receipt transmission method in a BeiDou communication system provided in the embodiments of this application.

[0426] Figure 13 A flowchart illustrating a transmission control method in a BeiDou communication system provided in an embodiment of this application is shown.

[0427] like Figure 13 As shown, the inbound transmission control method in this BeiDou communication system includes the following steps:

[0428] S1301, The transmitting device sends the first MDCPPDU of the first application layer message to the receiving device.

[0429] The header information of the first MDCPPDU includes a successor indication field, which indicates the order of the first MDCPPDU within the first application layer message. For a detailed description of the MDCPPDU, please refer to the foregoing embodiments; further details will not be repeated here.

[0430] S1302, The receiving device obtains the first application layer message based on the first MDCPPDU.

[0431] After the receiving device determines that the first MDCPPDU is the last MDCPPDU among the M MDCPPDUs in the first application layer message, the receiving device obtains the first application layer message based on the first MDCPPDU. Here, M is a positive integer. For a detailed description of obtaining the first application layer message based on the MDCPPDU, please refer to the preceding... Figure 2B , Figure 3B The embodiments shown are not described in detail here.

[0432] S1303, The receiving device generates the first application layer receipt information.

[0433] The first application layer receipt information is used to indicate the result of the receiving device parsing the first application layer message.

[0434] The specific process for generating the first application layer receipt information can be found in the aforementioned embodiment, and will not be repeated here.

[0435] S1304. The receiving device sends the first application layer receipt information to the sending device.

[0436] For details on how the receiving device generates the first application layer receipt information, please refer to the aforementioned... Figures 7-11 The embodiments described herein will not be repeated here.

[0437] Specifically, the operations performed by the sending device based on the first application layer acknowledgment information when sending application layer messages can be referred to the foregoing. Figures 7-11 The embodiments shown are not described in detail here.

[0438] The following describes some possible implementation methods for the sending device.

[0439] In one possible implementation, the sending device sends the first MDCP PDU in the first application layer message to the receiving device, specifically including:

[0440] The transmitting device sends the first MDCP PDU as the first Satellite Link Control Layer Service Data Unit (SLC SDU) of the transmitting device's SLC layer from the transmitting device's MDCP layer to the transmitting device's SLC layer.

[0441] The transmitting device splits the first SLC SDU into N Satellite Link Control Layer Protocol Data Units (SLCPDUs) at its SLC layer, where N is a positive integer. Each of the N SLCPDUs includes the first SLCPDU. The frame header information of the first SLCPDU includes a total frame count field and a frame sequence number field. The total frame count field indicates the total number N of SLCPDUs included in the first SLC SDU, and the frame sequence number field indicates the frame sequence number of the first SLC PDU within the first SLC SDU.

[0442] The transmitting device sends N SLC PDUs to the receiving device.

[0443] For details, please refer to the above. Figure 4 The embodiments shown are not described in detail here.

[0444] In one possible implementation, the first application layer acknowledgment information is also used to indicate that the receiving device has received all N SLCPDUs in the first SLCSDU. In this way, the sending device can determine, through the first application layer acknowledgment information, that the receiving device has received all SLCPDUs corresponding to the application layer message.

[0445] For details, please refer to the above. Figure 11 The embodiments shown are not described in detail here.

[0446] In one possible implementation, before the transmitting device receives the first application layer acknowledgment information sent by the receiving device, the method further includes: the transmitting device receiving a first acknowledgment character ACK sent by the receiving device. The first ACK is used to indicate that the receiving device has collected N SLCPDUs from the first SLCSDU.

[0447] For details, please refer to the above. Figure 7 The embodiments shown are not described in detail here.

[0448] In one possible implementation, before the transmitting device receives the first application layer acknowledgment information sent by the receiving device, the method further includes: the transmitting device receiving a second acknowledgment character ACK sent by the receiving device. The first ACK is used to indicate the frame sequence number of an SLC PDU that the receiving device has not received in the first SLC SDU.

[0449] The transmitting device retransmits the SLC PDU that the receiving device did not receive in the first SLC SDU to the receiving device.

[0450] For details, please refer to the above. Figure 7 , Figure 11 The embodiments shown are not described in detail here.

[0451] This ensures that the receiving device receives the complete application layer message.

[0452] In one possible implementation, the transmitting device sends N SLC PDUs to the receiving device, specifically including: the transmitting device sending the first SLCPDU from the transmitting device's SLC layer to the physical PHY layer as the first user frame of the transmitting device's PHY layer.

[0453] The transmitting device performs physical layer processing on the first user frame to obtain the first inbound data.

[0454] The transmitting device sends the first incoming data to the receiving device.

[0455] For details, please refer to the above. Figure 2A , Figure 3A The embodiments shown are not described in detail here.

[0456] In one possible implementation, before the sending device sends the first MDCPPDU in the first application layer message to the receiving device, the method further includes: the sending device obtaining the first application layer message sent by the application layer of the sending device at the message data aggregation MDCP layer.

[0457] The transmitting device treats the first application layer message as an MDCP SDU at the MDCP layer and splits the MDCP SDU into M MDCP PDUs. Here, M is a positive integer. The M MDCP PDUs include the first MDCP PDU.

[0458] For details, please refer to the above. Figure 2A , Figure 3A The embodiments shown are not described in detail here.

[0459] In one possible implementation, the method further includes: the transmitting device sending M MDCP PDUs from the MDCP layer to the SLC layer as M SLC SDUs of the SLC layer, wherein the M SLC SDUs include the first SLC SDU.

[0460] For details, please refer to the above. Figure 7 , Figure 11 The embodiments shown are not described in detail here.

[0461] In one possible implementation, before the sending device obtains the first application layer message sent by the application layer of the sending device at the MDCP layer, the method further includes: the sending device obtaining raw data.

[0462] The transmitting device encodes and compresses the raw data at the application layer to obtain the first compressed data.

[0463] The sending device encrypts the first compressed data at the application layer to obtain the first encrypted data.

[0464] The sending device adds a message header to the first encrypted data header to obtain the first application layer message. The message header includes a compression indicator field and an encryption indicator field. The compression indicator field indicates the encoding compression algorithm used when compressing the original data, and the encryption indicator field indicates the encryption algorithm used when encrypting the first compressed data.

[0465] For details, please refer to the above. Figure 7 , Figure 11 The embodiments shown are not described in detail here.

[0466] In one possible implementation, after the sending device receives the first application layer acknowledgment information sent by the receiving device, the method further includes: the sending device determining, based on the first application layer acknowledgment information, that the receiving device has failed to parse the first application layer message, and the sending device retransmitting the first application layer message to the receiving device.

[0467] For details, please refer to the above. Figure 7 The embodiments shown are not described in detail here.

[0468] In this way, when the sending device determines that the receiving device has failed to parse the application layer message, it can resend the application layer message, thus avoiding the situation where the receiving device fails to parse the application layer message due to data errors during transmission.

[0469] In one possible implementation, the first application layer receipt information includes a first parsing result, wherein the first parsing result is used to indicate that the receiving device failed to decrypt the first application layer message. After the sending device receives the first application layer receipt information sent by the receiving device, the method further includes: the sending device and the receiving device negotiating key information.

[0470] The sending device encrypts the first compressed data based on the negotiated key information to obtain the second encrypted data.

[0471] The sending device sends a second application layer message containing the second encrypted data to the receiving device.

[0472] For details, please refer to the above. Figure 7 The embodiments shown are not described in detail here.

[0473] In one possible implementation, the first application layer acknowledgment information includes a second parsing result, wherein the second parsing result is used to indicate that the receiving device failed to decode and decompress the application layer message. After the sending device receives the first application layer acknowledgment information sent by the receiving device, the method further includes: the sending device negotiating a codebook with the receiving device based on the second parsing result.

[0474] The transmitting device encodes and compresses the original data based on the negotiated codebook to obtain the second compressed data.

[0475] The sending device encrypts the second compressed data to obtain the third encrypted data.

[0476] The sending device sends a third application layer message to the receiving device. The third application layer message includes third encrypted data.

[0477] For details, please refer to the above. Figure 7 The embodiments shown are not described in detail here.

[0478] In one possible implementation, the aforementioned transmitting device is a terminal, and the receiving device is a BeiDou network device.

[0479] For details, please refer to the above. Figure 7 , Figure 11 The embodiments shown are not described in detail here.

[0480] In one possible implementation, the aforementioned transmitting device is a BeiDou network device, and the receiving device is a terminal.

[0481] For details, please refer to the above. Figure 7 , Figure 11 The embodiments shown are not described in detail here.

[0482] The following describes some possible implementation methods for the receiving device.

[0483] In one possible implementation, before the receiving device generates the first application layer receipt information, the method further includes: the receiving device decrypting the first encrypted data in the first application layer message, and obtaining the first compressed data after successful decryption.

[0484] For details, please refer to the above. Figure 7 , Figure 11 The embodiments shown are not described in detail here.

[0485] In one possible implementation, after the receiving device decrypts the first encrypted data in the first application layer message and obtains the first compressed data after successful decryption, the method further includes: the receiving device decoding and decompressing the first compressed data to obtain the original data.

[0486] For details, please refer to the above. Figure 7 , Figure 11 The embodiments shown are not described in detail here.

[0487] In one possible implementation, before the receiving device generates the first application layer receipt information, the method further includes: the receiving device failing to decrypt the first encrypted data.

[0488] The receiving device generates a first application layer receipt. This first application layer receipt includes a first parsing result, which indicates that the receiving device has failed to decrypt.

[0489] For details, please refer to the above. Figure 7 , Figure 11 The embodiments shown are not described in detail here.

[0490] In this way, the receiving device can generate an application layer receipt message to indicate that the receiving device failed to decrypt the application layer message when decryption fails.

[0491] In one possible implementation, before the receiving device generates the first application layer receipt information, the method further includes: the receiving device failing to decode or decompress the first compressed data.

[0492] The receiving device generates a first application layer receipt. This first application layer receipt includes a second parsing result, which indicates that the receiving device has failed to decode.

[0493] For details, please refer to the above. Figure 7 , Figure 11 The embodiments shown are not described in detail here.

[0494] In this way, the receiving device can generate application layer receipt information to indicate that the receiving device failed to decode the application layer message when decoding fails.

[0495] In one possible implementation, the first application layer receipt information includes a third parsing result, which is used to indicate that the receiving device has successfully parsed the application layer message.

[0496] For details, please refer to the above. Figure 7 , Figure 11 The embodiments shown are not described in detail here.

[0497] In this way, the receiving device can generate an application layer receipt message indicating that the application layer message has been successfully parsed when the parsing is successful.

[0498] In one possible implementation, the method further includes: when the receiving device is a BeiDou network device 200, the raw data can be sent to the cellular user equipment via the cellular network.

[0499] For details, please refer to the above. Figure 7 , Figure 11 The embodiments shown are not described in detail here.

[0500] In this way, the receiving device can forward the data to the user equipment under the cellular network when the resolution is successful.

[0501] In one possible implementation, before the receiving device receives the first MDCPPDU of the first application layer message sent by the sending device, the method further includes: the receiving device obtaining the first inbound data sent by the sending device at the PHY layer.

[0502] The receiving device performs physical layer processing based on the first incoming data to obtain the first user frame.

[0503] The receiving device presents the first user frame as the first SLC PDU in the receiving device's SLC layer from the PHY layer to the receiving device's SLC layer.

[0504] For details, please refer to the above. Figure 7 , Figure 11 The embodiments shown are not described in detail here.

[0505] In one possible implementation, after the receiving device presents the first user frame as the first SLC PDU in the receiving device's SLC layer from the PHY layer to the receiving device's SLC layer, the method further includes: the receiving device receiving X SLC PDUs from the first SLC SDU sent by the transmitting device, where X is a positive integer. The X SLC PDUs include the first SLC PDU, and the frame header information of the first SLC PDU includes a total frame count field and a frame sequence number field. The total frame count field indicates the total number N of SLCPDUs included in the first SLC SDU, where N is a positive integer, and the frame sequence number field indicates the frame sequence number of the first SLC PDU within the first SLC SDU.

[0506] When X is less than N, the receiving device sends a second ACK to the transmitting device, wherein the second ACK is used to indicate the frame sequence number of the SLC PDU that the receiving device did not receive in the first SLCSDU.

[0507] For details, please refer to the above. Figure 7 , Figure 11 The embodiments shown are not described in detail here.

[0508] In this way, the receiving device can notify the sending device to retransmit the lost SLCPDU.

[0509] In one possible implementation, after the receiving device receives X SLC PDUs from the first SLC SDU sent by the transmitting device, the method further includes: when X equals N, the receiving device concatenates the X SLC PDUs into a first SLC SDU at the SLC layer, and reports the first SLC SDU as the first MDCP PDU of the MDCP layer from the receiving device's SLC layer to the receiving device's MDCP layer.

[0510] For details, please refer to the above. Figure 7 , Figure 11 The embodiments shown are not described in detail here.

[0511] In one possible implementation, after the receiving device receives X SLC PDUs from the first SLC SDU sent by the transmitting device, the method further includes: when X equals N, the receiving device sends a first ACK to the transmitting device, wherein the first ACK is used to indicate that the receiving device has received all N SLC PDUs from the first SLC SDU.

[0512] For details, please refer to the above. Figure 7 , Figure 11 The embodiments shown are not described in detail here.

[0513] In one possible implementation, after the receiving device determines that the first MDCPPDU is the last MDCPPDU among the M MDCPPDUs in the application layer message, the receiving device obtains the application layer message based on the first MDCPPDU. Specifically, the receiving device concatenates the M MDCP PDUs at the MDCP layer to obtain an MDCPSDU, and reports the MDCP SDU as an application layer message from the MDCP layer to the application layer.

[0514] For details, please refer to the above. Figure 7 , Figure 11 The embodiments shown are not described in detail here.

[0515] In one possible implementation, the receiving device sends the first application layer receipt information to the sending device, specifically including: the receiving device sending the first application layer receipt information from the application layer of the receiving device to the SLC layer of the receiving device through a preset interface.

[0516] After the receiving device adds frame header information to the first application layer acknowledgment information at the SLC layer, it sends the first application layer acknowledgment information with the added frame header information to the physical layer, thus obtaining an acknowledgment frame. The frame header information includes a frame type field, which indicates the frame type of the user frame.

[0517] The receiving device sends an acknowledgment frame to the sending device.

[0518] For details, please refer to the above. Figures 7-11 The embodiments shown are not described in detail here.

[0519] In one possible implementation, the receiving device sends the first application layer receipt information to the sending device, specifically including:

[0520] The receiving device encapsulates the first application layer receipt information into an application layer receipt message and sends the application layer receipt message to the sending device.

[0521] For details, please refer to the above. Figures 7-11 The embodiments shown are not described in detail here.

[0522] In one possible implementation, the aforementioned transmitting device is a terminal, and the receiving device is a BeiDou network device.

[0523] For details, please refer to the above. Figures 7-11 The embodiments shown are not described in detail here.

[0524] In one possible implementation, the aforementioned transmitting device is a BeiDou network device, and the receiving device is a terminal.

[0525] For details, please refer to the above. Figures 7-11 The embodiments shown are not described in detail here.

[0526] The foregoing details the method provided in this application. To facilitate better implementation of the above-described solutions in the embodiments of this application, corresponding apparatus or devices are also provided in the embodiments of this application.

[0527] This application embodiment can divide the terminal 100 and Beidou network device 200 into functional modules according to the above method example. For example, each function can be divided into its own functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. It should be noted that the module division in this application embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

[0528] The following will combine Figures 14 to 17 The communication device of the embodiments of this application is described in detail.

[0529] In the case of using integrated units, see Figure 14 , Figure 14 This is a schematic diagram of the structure of the communication device 1400 provided in an embodiment of this application. The communication device 1400 can be the terminal 100 in the above embodiments. Optionally, the communication device 1400 can be a chip / chip system, such as a Beidou communication chip. Figure 14 As shown, the communication device 1400 may include a transceiver unit 1410 and a processing unit 1420.

[0530] In one inbound design, the transceiver unit 1410 can be used to send a first MDCPPDU in a first application layer message to the BeiDou network device 200. The header information of the first MDCPPDU includes a successor indication field. The successor indication field is used to indicate the order of the first MDCPPDU in the first application layer message.

[0531] The transceiver unit 1410 can be used to receive the first application layer receipt information returned by the Beidou network device 200 when the first MDCPPDU is the last MDCPPDU in the first application layer message. The first application layer receipt information is used to instruct the Beidou network device 200 on the result of parsing the first application layer message.

[0532] The processing unit 1420 can be used to generate the first application layer message.

[0533] In one outbound design, the transceiver unit 1410 can be used to receive a first MDCPPDU. The header information of the first MDCPPDU includes a successor indication field. This successor indication field indicates the order of the first MDCPPDU within a first application layer message.

[0534] The processing unit 1420 can be used to obtain the first application layer message based on the first MDCPPDU after determining that the first MDCPPDU is the last MDCPPDU among the M MDCPPDUs in the first application layer message; where M is a positive integer.

[0535] The processing unit 1420 can be used to generate first application layer receipt information, which is used to instruct the terminal 100 on the result of parsing the first application layer message.

[0536] The transceiver unit 1410 can be used to send first application layer receipt information to the Beidou network device 200.

[0537] Optionally, the transceiver unit 1410 can also be used to perform the above-mentioned tasks. Figure 13 The method embodiment shown illustrates the functional steps related to sending and receiving performed by terminal 100.

[0538] Optionally, the processing unit 1420 can also be used to perform the above-mentioned tasks. Figure 13 The method embodiment shown illustrates the functional steps performed by terminal 100 related to protocol parsing, encapsulation, and computation determination.

[0539] It should be understood that the communication device 1200 in this design can perform the method steps executed by the terminal 100 in the aforementioned embodiment, and for the sake of brevity, it will not be described again here.

[0540] In the case of using integrated units, see Figure 15 , Figure 15 This is a schematic diagram of the communication device 1500 provided in this embodiment. The communication device 1500 can be the BeiDou network device 200 in the above embodiments. Optionally, the communication device 1500 can be a specific network element in the BeiDou network device 200, such as one or a combination of multiple network elements from the BeiDou ground transceiver station 22, the BeiDou central station 23, and the BeiDou short message fusion communication platform 24. Figure 15 As shown, the communication device 1500 may include a transceiver unit 1510 and a processing unit 1520.

[0541] In one inbound design, the transceiver unit 1510 can be used to receive a first MDCPPDU. The header information of the first MDCPPDU includes a successor indication field. This successor indication field indicates the order of the first MDCPPDU within a first application layer message.

[0542] The processing unit 1520 can be used to obtain the first application layer message based on the first MDCPPDU after determining that the first MDCPPDU is the last MDCPPDU among the M MDCPPDUs in the first application layer message; where M is a positive integer.

[0543] The processing unit 1520 can be used to generate first application layer receipt information, which is used to instruct the Beidou network device 200 on the result of parsing the first application layer message.

[0544] The transceiver unit 1510 can be used to send the first application layer receipt information to the terminal 100.

[0545] In one outbound design, the transceiver unit 1510 can be used to send a first MDCPPDU in a first application layer message to the terminal 100. The header information of the first MDCPPDU includes a successor indication field. The successor indication field is used to indicate the order of the first MDCPPDU in the first application layer message.

[0546] The transceiver unit 1510 can be used to receive first application layer receipt information returned by the terminal 100 when the first MDCPPDU is the last MDCPPDU in the first application layer message. The first application layer receipt information is used to instruct the terminal 100 on the result of parsing the first application layer message.

[0547] The processing unit 1520 can be used to generate the first application layer message.

[0548] Optionally, the transceiver unit 1510 can also be used to perform the above-mentioned tasks. Figure 13 The method embodiment shown illustrates the functional steps related to sending and receiving performed by the BeiDou network device 200.

[0549] Optionally, the processing unit 1520 can also be used to execute the relevant protocol parsing and encapsulation and calculation determination functional steps performed by the Beidou network device 200 in the method embodiment shown in Figure 13 above.

[0550] It should be understood that the communication device 1500 in this design can perform the method steps executed by the Beidou network device 200 in the aforementioned embodiment, and for the sake of brevity, it will not be described again here.

[0551] The terminal 100 and Beidou network device 200 of this application embodiment have been described above. It should be understood that any device possessing the above-described... Figure 14 Any product of the aforementioned terminal 100 functions, as long as it possesses the above-mentioned features. Figure 15 Any form of product that incorporates the functions of the Beidou network device 200 falls within the protection scope of the embodiments of this application.

[0552] As a possible product form, the terminal 100 described in this application embodiment can be implemented using a general bus architecture.

[0553] See Figure 16 , Figure 16This 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 terminal 100, 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., baseband chip, terminal, terminal chip), execute computer programs, and process data from these 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.

[0554] 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.

[0555] The processor 1601, transceiver 1602, and memory 1604 can be connected via a communication bus.

[0556] In one design, the communication device 1600 can be used to perform the functions of the terminal 100 in the aforementioned embodiments; the processor 1601 can be used to perform the aforementioned... Figure 13 The terminal 100 in the illustrated embodiment performs the functional steps related to protocol parsing and encapsulation, as well as calculation and / or other processes used in the technology described herein; the transceiver 1602 can be used to perform the above. Figure 13 The terminal 100 in the illustrated embodiment performs functional steps related to sending and receiving and / or other processes used in the techniques described herein.

[0557] In any of the above designs, the processor 1601 may include a transceiver for implementing receive and transmit functions. For example, the transceiver may be a transceiver circuit, an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit for implementing receive and transmit functions may be separate or integrated. The aforementioned transceiver circuit, interface, or interface circuit may be used for reading and writing code / data, or it may be used for transmitting or relaying signals.

[0558] In any of the above designs, the processor 1601 may store instructions, which may be computer programs. These computer programs, running on the processor 1601, cause the communication device 1600 to execute the method steps executed by the terminal 100 in the above method embodiments. The computer program may be embedded in the processor 1600; in this case, the processor 1601 may be implemented in hardware.

[0559] In one implementation, the communication device 1600 may include circuitry capable of performing the functions of transmitting, receiving, or communicating as described in the foregoing method embodiments. The processor and transceiver described in this application can be implemented on integrated circuits (ICs), analog ICs, radio frequency integrated circuits (RFICs), mixed-signal ICs, application-specific integrated circuits (ASICs), printed circuit boards (PCBs), electronic devices, etc. The processor and transceiver can also be manufactured using various IC process technologies, such as complementary metal oxide semiconductors (CMOS), n-metal-oxide-semiconductor (NMOS), positive-channel metal oxide semiconductors (PMOS), bipolar junction transistors (BJTs), bipolar CMOS (BiCMOS), silicon germanium (SiGe), gallium arsenide (GaAs), etc.

[0560] The scope of the communication device described in this application is not limited thereto, and the structure of the communication device may vary. Figure 16 The communication device 1600 may be a standalone device or part of a larger device. For example, the communication device 1600 may be:

[0561] (1) Independent integrated circuit IC, or chip, or chip system or subsystem;

[0562] (2) A collection of one or more ICs, optionally including storage components for storing data and computer programs;

[0563] (3) ASIC, such as modem;

[0564] (4) Modules that can be embedded in other devices;

[0565] (5) Receivers, terminals, smart terminals, cellular phones, wireless devices, handheld devices, mobile units, vehicle-mounted devices, network devices, cloud devices, artificial intelligence devices, etc.

[0566] (6) Others, etc.

[0567] 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.

[0568] See Figure 17 , Figure 17 This is a schematic diagram of the structure of the communication device 1700 provided in an embodiment of this application. The communication device 1700 may be a BeiDou network device 200, or a device therein. Figure 17 As shown, the communication device 1700 includes a processor 1701 and a transceiver 1702 internally connected and communicating with the processor. The processor 1701 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 1702, also known as a transceiver unit, transceiver, or transceiver circuit, is used to implement transceiver functions. The transceiver 1702 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 1700 may also include an antenna 1703 and / or a radio frequency unit (not shown in the figure). The antenna 1703 and / or radio frequency unit may be located inside the communication device 1700 or separate from the communication device 1700, that is, the antenna 1703 and / or radio frequency unit may be deployed remotely or in a distributed manner.

[0569] Optionally, the communication device 1700 may include one or more memories 1704, which may store instructions, which may be computer programs, that can be executed on the communication device 1700 to cause the communication device 1700 to perform the methods described in the above method embodiments. Optionally, the memory 1704 may also store data. The communication device 1700 and the memory 1704 may be provided separately or integrated together.

[0570] The processor 1701, transceiver 1702, and memory 1704 can be connected via a communication bus.

[0571] In one design, the communication device 1700 can be used to perform the functions of the BeiDou network device 200 in the aforementioned embodiments: the processor 1701 can be used to perform the above-mentioned functions. Figure 13 The BeiDou network device 200 in the illustrated embodiment performs the relevant protocol parsing, encapsulation, and computational determination functional steps and / or other processes used in the technology described herein; the transceiver 1702 can be used to perform the above. Figure 13 The BeiDou network device 200 in the illustrated embodiment performs functional steps related to sending and receiving and / or other processes used in the technology described herein.

[0572] In any of the above designs, the processor 1701 may include a transceiver for implementing receive and transmit functions. For example, the transceiver may be a transceiver circuit, an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit for implementing receive and transmit functions may be separate or integrated. The aforementioned transceiver circuit, interface, or interface circuit may be used for reading and writing code / data, or it may be used for transmitting or relaying signals.

[0573] In any of the above designs, the processor 1701 may store instructions, which may be computer programs. These computer programs, running on the processor 1701, cause the communication device 1700 to execute the method steps performed by the terminal 100 in the above method embodiments. The computer program may be embedded in the processor 1701; in this case, the processor 1701 may be implemented in hardware.

[0574] This application also provides a computer-readable storage medium storing computer program code, which, when executed by the processor, causes the communication device to perform the method in any of the foregoing embodiments.

[0575] This application also provides a computer program product that, when run on a computer, causes the computer to perform the methods in any of the foregoing embodiments.

[0576] This application also provides a communication device, which can exist in the form of a chip. 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 can execute the method in any of the foregoing embodiments.

[0577] This application also provides a BeiDou communication system, including a terminal 100 and a BeiDou network device 200, which can execute the methods in any of the foregoing embodiments.

[0578] This application fully describes the short message communication function in the BeiDou communication system. It is understood that other satellite systems may also support short message communication functions. Therefore, it is not limited to the BeiDou communication system. If other satellite systems also support short message communication functions, the method described in this application is also applicable to the communication of other satellite systems.

[0579] The steps of the methods or algorithms described in this application can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory (RAM), flash memory, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Alternatively, the ASIC can reside in a core network interface device. Of course, the processor and storage medium can also exist as discrete components in the core network interface device.

[0580] Those skilled in the art will recognize that, in one or more of the examples above, the functions described in this application can be implemented using hardware, software, firmware, or any combination thereof. When implemented in software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media include computer-readable storage media and communication media, wherein communication media include any medium that facilitates the transmission of a computer program from one place to another. Storage media can be any available medium accessible to a general-purpose or special-purpose computer.

[0581] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for transmitting application layer receipts in a satellite communication system, characterized in that, include: The terminal sends the first message data aggregation layer protocol data unit (MDCPPDU) in the first application layer message to the satellite network device; wherein, the header information of the first MDCPPDU includes a successor indication field; the successor indication field is used to indicate the order of the first MDCPPDU in the first application layer message; When the first MDCPPDU is the last MDCPPDU in the first application layer message, the terminal receives the first application layer receipt information sent by the satellite network device; wherein, the first application layer receipt information is used to instruct the satellite network device on the result of parsing the first application layer message.

2. The method according to claim 1, characterized in that, The terminal sends the first MDCP PDU in the first application layer message to the satellite network device, specifically including: The terminal uses the first MDCP PDU as the first Satellite Link Control Layer Service Data Unit (SLC SDU) of the terminal's SLC layer and sends it from the terminal's MDCP layer to the terminal's SLC layer. The terminal splits the first SLC SDU into N Satellite Link Control Layer Protocol Data Units (SLCPDUs) at the terminal's SLC layer, where N is a positive integer; wherein, the N SLCPDUs include the first SLCPDU; The terminal sends the N SLC PDUs to the satellite network device.

3. The method according to claim 2, characterized in that, The first application layer receipt information is also used to indicate that the satellite network device has received N SLCPDUs in the first SLCSDU.

4. The method according to claim 1, characterized in that, The header of the first application layer message includes a receipt indication field, which is used to indicate whether the satellite network device has responded with an application layer receipt.

5. The method according to claim 2, characterized in that, Before the terminal receives the first application layer acknowledgment information sent by the satellite network device, the method further includes: The terminal receives a first acknowledgment character ACK sent by the satellite network device; wherein the first ACK is used to indicate that the satellite network device has collected N SLCPDUs in the first SLCSDU.

6. The method according to claim 3, characterized in that, Before the terminal receives the first application layer acknowledgment information sent by the satellite network device, the method further includes: The terminal receives a second acknowledgment character ACK sent by the satellite network device; wherein, the second ACK is used to indicate the frame sequence number of the SLC PDU that the satellite network device did not receive in the first SLC SDU; The terminal retransmits the SLC PDU that the satellite network device did not receive in the first SLC SDU to the satellite network device.

7. The method according to claim 5, characterized in that, Before the terminal receives the first acknowledgment character ACK sent by the satellite network device, the method further includes: The terminal receives a second acknowledgment character ACK sent by the satellite network device; wherein, the second ACK is used to indicate the frame sequence number of the SLC PDU that the satellite network device did not receive in the first SLC SDU; The terminal retransmits the SLC PDU that the satellite network device did not receive in the first SLC SDU to the satellite network device.

8. The method according to any one of claims 2, 3, 5-7, characterized in that, The terminal sends the N SLCPDUs to the satellite network device, specifically including: The terminal sends the first SLCPDU from the terminal's SLC layer to the physical PHY layer as the first user frame of the terminal's PHY layer; The terminal performs physical layer processing on the first user frame to obtain the first inbound data. The terminal sends the first incoming data to the satellite network device.

9. The method according to claim 1, characterized in that, Before the terminal sends the first MDCPPDU in the first application layer message to the satellite network device, the method further includes: The terminal obtains the first application layer message sent by the application layer at the message data aggregation MDCP layer; The terminal takes the first application layer message as an MDCP SDU at the MDCP layer, and after adding padding data and a redundancy length indication field to the MDCP SDU, splits it into M MDCP PDUs; where M is a positive integer; the redundancy length indication field is used to indicate the data length of the padding data, and the M MDCP PDUs include the first MDCP PDU.

10. The method according to claim 9, characterized in that, The method further includes: The terminal sends the M MDCP PDUs from the MDCP layer to the SLC layer as the M SLC SDUs of the SLC layer, and the M SLC SDUs include the first SLC SDU.

11. The method according to claim 9 or 10, characterized in that, Before the terminal obtains the first application layer message sent by the application layer at the MDCP layer, the method further includes: The terminal acquires raw data; The terminal encodes and compresses the original data at the application layer to obtain first compressed data; The terminal encrypts the first compressed data at the application layer to obtain the first encrypted data; The terminal adds message header information to the first encrypted data header to obtain the first 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 encoding compression algorithm used when compressing the original data, and the encryption indication field is used to indicate the encryption algorithm used when encrypting the first compressed data.

12. The method according to claim 1, characterized in that, After the terminal receives the first application layer acknowledgment information sent by the satellite network device, the method further includes: The terminal determines that the satellite network device failed to parse the first application layer message based on the first application layer receipt information, and the terminal retransmits the first application layer message to the satellite network device.

13. The method according to claim 11, characterized in that, The first application layer receipt information includes a first parsing result, wherein the first parsing result is used to indicate that the satellite network device failed to decrypt the first application layer message; after the terminal receives the first application layer receipt information sent by the satellite network device, the method further includes: The terminal negotiates key information with the satellite network equipment; The terminal encrypts the first compressed data based on the negotiated key information to obtain the second encrypted data; The terminal sends a second application layer message containing the second encrypted data to the satellite network device.

14. The method according to claim 11, characterized in that, The first application layer receipt information includes a second parsing result, wherein the second parsing result is used to indicate that the satellite network device failed to decode and decompress the application layer message; after the terminal receives the first application layer receipt information sent by the satellite network device, the method further includes: The terminal negotiates a codebook based on the second parsing result and the satellite network equipment. The terminal encodes and compresses the original data based on the negotiated codebook to obtain second compressed data; The terminal encrypts the second compressed data to obtain the third encrypted data; The terminal sends a third application layer message to the satellite network device, the third application layer message including the third encrypted data.

15. A method for transmitting application layer receipts in a satellite communication system, characterized in that, include: The satellite network device receives the first MDCPPDU of the first application layer message sent by the terminal; wherein the header information of the first MDCPPDU includes a successor indication field; the successor indication field is used to indicate the order of the first MDCPPDU in the first application layer message; After the satellite network device determines that the first MDCPPDU is the last MDCPPDU among the M MDCPPDUs in the first application layer message, the satellite network device obtains the first application layer message based on the first MDCPPDU; where M is a positive integer; The satellite network device generates a first application layer receipt information, which is used to instruct the satellite network device on the result of parsing the first application layer message. The satellite network device sends the first application layer receipt information to the terminal.

16. The method according to claim 15, characterized in that, Before the satellite network device generates the first application layer receipt information, the method further includes: The satellite network device decrypts the first encrypted data in the first application layer message and obtains the first compressed data after successful decryption.

17. The method according to claim 16, characterized in that, After the satellite network device decrypts the first encrypted data in the first application layer message and obtains the first compressed data after successful decryption, the method further includes: The satellite network equipment decodes and decompresses the first compressed data to obtain the original data.

18. The method according to claim 15, characterized in that, Before the satellite network device generates the first application layer receipt information, the method further includes: The satellite network device failed to decrypt the first encrypted data of the first application layer message. The satellite network device generates a first application layer receipt; wherein the first application layer receipt includes a first parsing result, which is used to indicate that the satellite network device failed to decrypt.

19. The method according to claim 16, characterized in that, Before the satellite network device generates the first application layer receipt information, the method further includes: The satellite network device failed to decode and decompress the first compressed data. The satellite network device generates a first application layer receipt; wherein the first application layer receipt includes a second parsing result, the second parsing result being used to indicate that the satellite network device failed to decode.

20. The method according to claim 17, characterized in that, The first application layer receipt information includes a third parsing result, which is used to indicate that the satellite network device has successfully parsed the application layer message.

21. The method according to claim 17 or 20, characterized in that, The method further includes: The satellite network equipment transmits the raw data to cellular user equipment via the cellular network.

22. The method according to claim 15, characterized in that, Before the satellite network device receives the first MDCPPDU of the first application layer message sent by the terminal, the method further includes: The satellite network equipment obtains the first inbound data sent by the terminal at the PHY layer; The satellite network device performs physical layer processing based on the first inbound data to obtain the first user frame; The satellite network device presents the first user frame as the first SLCPDU in the SLC layer of the satellite network device from the PHY layer to the SLC layer of the satellite network device.

23. The method according to claim 22, characterized in that, After the satellite network device presents the first user frame as the first SLC PDU in the SLC layer of the satellite network device from the PHY layer to the SLC layer of the satellite network device, the method further includes: The satellite network device receives X SLC PDUs from the first SLC SDU sent by the terminal, where X is a positive integer; wherein, the X SLC PDUs include the first SLC PDU, and the frame header information of the first SLC PDU includes a total frame count field and a frame sequence number field; the total frame count field is used to indicate the total number N of SLCPDUs included in the first SLC SDU, where N is a positive integer, and the frame sequence number field is used to indicate the frame sequence number of the first SLC PDU in the first SLC SDU; When X is less than N, the satellite network device sends a second ACK to the terminal, wherein the second ACK is used to indicate the frame sequence number of the SLC PDU that the satellite network device has not received in the first SLC SDU.

24. The method according to claim 23, characterized in that, After the satellite network device receives X SLC PDUs from the first SLC SDU sent by the terminal, the method further includes: When X equals N, the satellite network device splices the X SLC PDUs into the first SLC SDU at the SLC layer, and reports the first SLC SDU as the first MDCP PDU from the SLC layer of the satellite network device to the MDCP layer of the satellite network device.

25. The method according to claim 23 or 24, characterized in that, After the satellite network device receives X SLC PDUs from the first SLC SDU sent by the terminal, the method further includes: When X equals N, the satellite network device sends a first ACK to the terminal, wherein the first ACK is used to indicate that the satellite network device has collected N SLC PDUs in the first SLC SDU.

26. The method according to claim 15, characterized in that, After the satellite network device determines that the first MDCPPDU is the last MDCPPDU among the M MDCPPDUs in the application layer message, the satellite network device obtains the application layer message based on the first MDCPPDU, specifically including: The satellite network device concatenates the M MDCP PDUs at the MDCP layer to obtain an MDCPSDU, and then reports the MDCPSDU as an application layer message from the MDCP layer to the application layer.

27. The method according to claim 15, characterized in that, The satellite network device sends the first application layer receipt information to the terminal, specifically including: The satellite network device sends the first application layer receipt information from the application layer of the satellite network device to the SLC layer of the satellite network device through a preset interface; After the satellite network device adds frame header information to the first application layer receipt information at the SLC layer, it sends the first application layer receipt information with the added frame header information to the physical layer to obtain a receipt frame; wherein, the frame header information includes a frame type field, which is used to indicate the frame type of the user frame; The satellite network device sends the receipt frame to the terminal.

28. A satellite communication system, characterized in that, include: Terminal and satellite network equipment; among which: The terminal is used to send the first MDCPPDU of the first application layer message to the satellite network device; The satellite network equipment is used to receive the first MDCPPDU; The satellite network device is further configured to, after determining that the first MDCPPDU is the last MDCPPDU among the M MDCPPDUs in the first application layer message, obtain the first application layer message based on the first MDCPPDU; where M is a positive integer; The satellite network device is also configured to generate a first application layer receipt information, which is used to instruct the satellite network device on the result of parsing the first application layer message. The satellite network equipment is also used to send the first application layer receipt information to the terminal; The terminal is used to receive the first application layer receipt information.

29. A communication device, characterized in that, The device includes 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 together, the one or more memories being used to store computer program code, the computer program code including computer instructions, which, when executed by the one or more processors, cause the communication device to perform the method as described in any one of claims 1-14.

30. The communication device according to claim 29, characterized in that, The communication device is a terminal.

31. A communication device, characterized in that, The device includes 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 together, and the one or more memories are used to store computer program code, the computer program code including computer instructions, which, when executed by the one or more processors, cause the communication device to perform the method as described in any one of claims 15-27.

32. The communication device according to claim 31, characterized in that, The communication device is a satellite network equipment.

33. A computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to perform the method as described in any one of claims 1-14.

34. A computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to perform the method as described in any one of claims 15-27.

35. A chip or chip system, used in a terminal, characterized in that, It includes a processing circuit and an interface circuit, the interface circuit being used to receive code instructions and transmit them to the processing circuit, the processing circuit being used to execute the code instructions to perform the method as described in any one of claims 1-14.

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