CN116388834A

CN116388834A - Packet loss response method based on Beidou short message and terminal equipment

Info

Publication number: CN116388834A
Application number: CN202211734492.8A
Authority: CN
Inventors: 张焕彬; 陈力泉; 高峰; 许祥滨
Original assignee: Techtotop Microelectronics Co Ltd
Current assignee: Techtotop Microelectronics Co Ltd
Priority date: 2022-12-30
Filing date: 2022-12-30
Publication date: 2023-07-04

Abstract

The application is applicable to the technical field of satellites, and provides a packet loss response method and terminal equipment based on Beidou short messages, wherein the method comprises the following steps: if the response data frame fed back by the receiving terminal is received, acquiring a function code of a control domain in a frame head part of the response data frame; if the function code is the second bit value, identifying the response data frame as a packet loss feedback data frame; analyzing the packet loss feedback data frame based on the packet loss feedback frame format, and determining the packet loss data frame; and the packet loss data frame is sent to the Beidou satellite again, so that the packet loss data frame is sent to the receiving terminal through the Beidou satellite. The method can adopt the normalized coding technology and the framing technology to process, namely, the format of the packet loss feedback data frame is consistent with that of the sub-packet data frame, so that the processing difficulty of the sending terminal and the receiving terminal to the Beidou short message is reduced, the sending terminal is informed of specific data frames which are lost through the packet loss feedback data frame, and the communication efficiency is improved only by retransmitting the packet loss data frame.

Description

Packet loss response method based on Beidou short message and terminal equipment

Technical Field

The application belongs to the technical field of satellites, and particularly relates to a packet loss response method based on Beidou short messages and terminal equipment.

Background

The Beidou satellite navigation system (hereinafter referred to as Beidou system) is one of the existing global satellite navigation systems, and provides space-time infrastructure for all-weather, all-day and high-precision positioning, navigation and time service for global users. The Beidou system is widely applied to the fields of transportation, agriculture, forestry, fishery, hydrologic monitoring, weather forecast, communication time service, power dispatching, disaster relief, disaster reduction, public safety and the like, serves a plurality of important infrastructures, and generates remarkable economic benefit and social benefit. The Beidou short message service is a two-way message communication service provided by a Beidou satellite navigation system based on a satellite radio positioning system (radio determination satel-lite system, RDSS), and is one of important services of the Beidou satellite navigation system. At present, beidou short message communication provides services for public users. With more and more users, the types of the transmitted data are increased, the Beidou short messages transmitted through the Beidou satellite not only contain text type data, but also need to transmit data with larger data quantity such as pictures, voices and the like through the Beidou short messages under partial application scenes.

However, in the existing satellite message transmission technology, when the Beidou satellite system transmits the Beidou short message, the situation of packet loss may occur, and when the packet loss occurs in the case of packet transmission of the transmitted target data, the transmitting terminal needs to retransmit all packets of the whole frame of target data, so that the communication efficiency is greatly reduced, and the unnecessary data transmission quantity is increased.

Disclosure of Invention

The embodiment of the application provides a packet loss response method based on a Beidou short message and terminal equipment, which can solve the problem that the prior satellite message transmission technology is that a Beidou satellite system possibly has packet loss when transmitting the Beidou short message, and under the condition that the transmitted target data has packet loss transmission, if the packet loss occurs, a transmitting terminal needs to retransmit all packets of the whole frame of target data, thereby greatly reducing communication efficiency and increasing unnecessary data transmission quantity.

In a first aspect, an embodiment of the present application provides a packet loss response method based on a beidou short message, which is applied to a sending terminal, where the packet loss response method includes:

if a response data frame fed back by a receiving terminal is received, acquiring a function code of a control domain in a frame head part of the response data frame;

If the function code is a second bit value, identifying the response data frame as a packet loss feedback data frame;

analyzing the packet loss feedback data frame based on a packet loss feedback frame format, and determining a packet loss data frame;

and the packet loss data frame is sent to the Beidou satellite again, so that the packet loss data frame is sent to a receiving terminal through the Beidou satellite.

In a possible implementation manner of the first aspect, before the acquiring the function code of the control domain in the frame header portion of the response data frame if the response data frame fed back by the receiving terminal is received, the method further includes:

generating a plurality of sub-packet data frames in response to a transmission request of the target data; the packetized data frame includes a frame header portion and a data portion; the data part is generated according to a data format corresponding to the data type of the target data; the frame head part records the packetizing information of the packetizing data frame; the sub-packaging data frame is packaged based on Beidou short messages; the sub-packaging data frame supports multi-element heterogeneous data coding;

and sequentially sending the plurality of sub-packet data frames to a Beidou satellite according to the sub-packet information of the plurality of sub-packet data frames so as to forward the plurality of sub-packet data frames to a receiving terminal through the Beidou satellite.

In a possible implementation manner of the first aspect, the frame header portion includes: a control field and a frame sequence number;

the generating a plurality of packetized data frames in response to a request to send target data includes:

dividing the target data into a plurality of data blocks according to the maximum data volume of single transmission corresponding to the Beidou short message; the data amount of each data block is not greater than the maximum data amount;

respectively adding each data block to the data part in a preset frame template;

and setting all the function codes of the control domains in the preset frame template added with the data blocks as a first bit value, and setting the frame serial numbers as serial numbers corresponding to the target data, so as to generate the plurality of sub-packet data frames.

In a possible implementation manner of the first aspect, the adding each of the data blocks to the data portion in the preset frame template includes:

if the data type of the target data is text type, setting a data type identifier in the data part as a first bit value, setting an encryption field of the data part according to the encryption mode of the target data, and adding the data block into a character data field of the data part;

If the data type of the target data is an image type, setting the data type identifier as a second bit value, setting a format field of a data part according to the compression mode of the target data, and adding the data block into a pixel data field of the data part;

if the data type of the target data is an audio type, setting the data type identifier as a third bit value, setting a coding field of a data part according to the coding code rate of the target data, and adding the data block into the audio data field of the data part;

and if the data type of the target data is other types, setting the data type identifier to a fourth bit value, and adding the data block to an application data field of the data part.

In a possible implementation manner of the first aspect, the parsing the packet loss feedback data frame based on the packet loss feedback frame format, and determining the packet loss data frame includes:

reading a first byte of a data part in the packet loss feedback data frame, and determining the number of packet loss feedback information contained in the packet loss feedback data frame; each piece of packet loss feedback information is used for determining at least one lost or erroneous sub-packet data frame;

Sequentially acquiring each piece of packet loss feedback information from the data part in the packet loss feedback data frame;

and if the packet loss type field of the packet loss feedback information is a first bit value, identifying the packet loss feedback information as the packet loss feedback with the designated sequence number.

determining a first packet loss sequence number according to a packet loss batch and a packet loss mark carried in the packet loss feedback of the designated sequence number, and taking a sub-packet data frame corresponding to the first packet loss sequence number as the packet loss data frame;

if the packet loss type field is a second bit value, identifying the packet loss feedback information as end packet loss feedback;

according to the second packet loss sequence number carried by the last packet loss feedback, taking all the sub-packet data frames with the sub-packet sequence numbers larger than the second packet loss sequence number as the packet loss data frames; the second packet loss sequence number is the maximum value of the packet sequence numbers in the packet data frames received by the receiving terminal;

and if the packet loss type is a third bit value, identifying the packet loss feedback information as whole-frame packet loss feedback, and identifying the plurality of sub-packet data frames as the packet loss data frames.

In a second aspect, an embodiment of the present application provides a packet loss identification method based on a beidou short message, which is applied to a receiving terminal, where the receiving method includes:

receiving a plurality of sub-packet data frames forwarded by a Beidou satellite; the plurality of sub-packet data frames are sent to the Beidou satellite by the sending terminal; the plurality of packetized data frames including a frame header portion and a data portion; the sub-packaging data frame is packaged based on Beidou short messages; the sub-packaging data frame supports multi-element heterogeneous data coding;

determining a data type corresponding to the sub-package data frame according to the data part, and acquiring a data format corresponding to the data type;

if the received multiple sub-packet data frames meet the preset packet loss conditions, generating a packet loss feedback data frame; the function code of the control domain in the frame head part of the packet loss feedback data frame is a second bit value; the packet loss feedback data frame comprises at least one packet loss feedback information;

the packet loss feedback data frame is sent to the Beidou satellite, so that the packet loss feedback data frame is forwarded to the sending terminal through the Beidou satellite;

and receiving the packet loss data frame fed back by the Beidou satellite based on the packet loss feedback data frame.

In a possible implementation manner of the second aspect, the determining, according to the data portion, a data type corresponding to the packetized data frame, and obtaining a data format corresponding to the data type, includes:

if the function code of the control domain in the frame header part is a first bit value, recognizing that a first byte of the data part is a data type identifier;

if the data type identifier is a first bit value, the data type corresponding to the sub-packet data frame is a text type, an encryption field is extracted from the data part, an encryption mode corresponding to a data block of the sub-packet data frame is determined according to the encryption field, and the data block is processed in the encryption mode to obtain text data;

if the data type identifier is a second bit value, the data type is an image type, a format field is extracted from the data part, an image format corresponding to a data block of the sub-packet data frame is determined according to the format field, and the data block is processed through the image format to obtain pixel data;

if the data type identifier is a third bit value, the data type is an audio type, a coding field is extracted from the data part, a coding code rate corresponding to a data block of the sub-packet data frame is determined according to the coding field, and the data block is processed through the coding code rate to obtain audio data;

If the data type identifier is a fourth bit value, the data type is of other types, and the data block of the sub-packet data frame is processed through a preset analysis algorithm to obtain other data;

the text data, the image data, the audio data, and the other data are used to synthesize the target data.

In a possible implementation manner of the second aspect, before the parsing the plurality of sub-packet data frames based on the data format, the method further includes:

In a possible implementation manner of the second aspect, the packet loss feedback information includes: designating sequence number packet loss feedback, end packet loss feedback and whole frame packet loss feedback;

And if the received plurality of sub-packet data frames meet a preset packet loss condition, generating a packet loss feedback data frame, including:

if the data tail frames of the packet data frames are received and at least two packet data frames with discontinuous packet sequence numbers exist in the packet data frames, determining a first packet loss sequence number of packet loss according to the at least two packet data frames with discontinuous packet sequence numbers, and generating specified sequence number packet loss feedback based on the first packet loss sequence number; the packet loss batch and the packet loss mark in the specified sequence number packet loss feedback are determined based on the first packet loss sequence number; the packet loss type in the packet loss feedback of the appointed sequence number is a first bit value;

if the data tail frames of the packet data frames are not received within the preset waiting time, determining a second packet loss sequence number in the packet data frames, and generating tail packet loss feedback based on the second packet loss sequence number; the second packet loss data is the maximum value of the packet sequence number in the packet data frame; the packet loss type field in the last packet loss feedback is a second bit value;

if two sub-packet data frames with discontinuous frame sequence numbers are received, determining a lost frame sequence number according to the two sub-packet data frames with discontinuous frame sequence numbers, and generating whole-frame packet loss feedback based on the lost frame sequence number; and the packet loss type field of the whole frame packet loss feedback is a third bit value.

In a third aspect, embodiments of the present application provide a terminal device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, the processor implementing the method according to any one of the first aspect or the method according to any one of the second aspect when the computer program is executed by the processor.

In a fourth aspect, embodiments of the present application provide a computer-readable storage medium storing a computer program which, when executed by a processor, implements a method as in any one of the first aspect or a method as in any one of the second aspect.

In a fifth aspect, embodiments of the present application provide a computer program product, which when run on a server, causes the server to perform the method of any one of the first aspect or the method of any one of the second aspect described above.

Compared with the prior art, the embodiment of the application has the beneficial effects that: when the receiving terminal detects that the packet loss condition exists, a corresponding packet loss feedback data frame can be generated, the function code of the control domain in the frame header part in the packet loss feedback data frame is a second bit value, the packet loss feedback data frame and the sub-packet data frame sent by the sending terminal adopt the same frame format and are Beidou short messages generated through supporting multi-element heterogeneous data coding, therefore, when the sending terminal receives the response data frame sent by the receiving terminal, the sending terminal can identify the function code, when the function code is detected to be the second bit value, the sending terminal determines the function code to be the packet loss feedback data frame, determines the lost packet loss data frame, and sends the packet loss feedback data frame to the receiving terminal again through the Beidou satellite, so that the response to the packet loss condition is realized. Compared with the existing packet loss response technology, the method and the device have the advantages that when packet loss occurs, all packet-divided data frames of the whole frame of target data are not sent to the receiving terminal, and the designated packet-lost data frames can be sent to the receiving terminal by analyzing the packet loss feedback data frames, so that unnecessary sending operation is reduced; on the other hand, the data frame format adopted by the transmitting terminal is the same as the frame format of the packet loss feedback data frame transmitted by the receiving terminal, so that the purpose of multi-source heterogeneous coding can be realized, and the receiving terminal and the transmitting terminal can adopt a unified coding technology and decoding technology to code and decode different types of data, thereby greatly reducing the difficulty of decoding and coding and further reducing the pressure of data processing.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following description will briefly introduce the drawings that are needed in the embodiments or the description of the prior art, it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram of a beidou satellite system according to an embodiment of the present application;

fig. 2 is a schematic diagram of receiving a terminal device according to an embodiment of the present application;

fig. 3 is a data flow diagram of a sub-packet data frame based on a beidou short message according to an embodiment of the present application;

fig. 4 is an interaction flow chart of a data transmission method based on a beidou short message according to an embodiment of the present application;

FIG. 5 is a flowchart of a specific implementation of S401 according to an embodiment of the present application;

FIG. 6 is a schematic diagram of a target data packetization according to an embodiment of the present application;

fig. 7 is a flowchart of an implementation of a packet loss response method based on a beidou short message according to an embodiment of the present application;

fig. 8 is a schematic structural diagram of a packet loss response device based on a beidou short message provided in an embodiment of the present application;

Fig. 9 is a schematic structural diagram of a packet loss identification device based on a beidou short message provided in an embodiment of the present application;

fig. 10 is a schematic structural diagram of a terminal device provided in an embodiment of the present application.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system configurations, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

It should be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

In addition, in the description of the present application and the appended claims, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and are not to be construed as indicating or implying relative importance.

The packet loss response method based on the Beidou short message can be applied to a Beidou satellite system. Exemplary, fig. 1 shows a schematic diagram of a beidou satellite system according to an embodiment of the present application. Referring to fig. 1, the beidou satellite system includes: the Beidou satellite system comprises a Beidou satellite and at least two terminal devices, and optionally, the Beidou satellite system further comprises a background control center, wherein the background control center can receive and transmit Beidou short messages through an antenna radar. Wherein, the above-mentioned user terminal includes but is not limited to: electronic equipment such as smart phones, smart watches, tablet computers, notebook computers, ultra-mobile personal computer (UMPC) and netbooks can be used for realizing data transmission based on Beidou short messages. The embodiment of the application does not limit the specific type of the electronic device.

Of the two terminal devices, the terminal device 1 may be a transmitting terminal, and the terminal device 2 may be a receiving terminal. Of course, in some implementation scenarios, the terminal device 1 may also be a receiving terminal, and the terminal device 2 may be a transmitting terminal. Similarly, the background control center may be a transmitting terminal or a receiving terminal. Taking the terminal device 1 as a transmitting terminal for illustration, the terminal device 1 may encapsulate the required target data to obtain a plurality of sub-packet data frames, and send each sub-packet data frame to the beidou satellite in the form of a beidou short message, where the beidou satellite may forward the received sub-packet data frame to a corresponding receiving terminal, such as the terminal device 2.

Fig. 2 illustrates an exemplary reception diagram of a terminal device according to an embodiment of the present application. As shown in fig. 2, the terminal device may be the terminal device 1 or the terminal device 2 in fig. 1, which may be either a transmitting terminal or a receiving terminal. And are not limited thereto. The terminal equipment comprises a Beidou short message module and a wireless networking module (the wireless networking module can comprise a Bluetooth module, a wifi module, a radio frequency communication module and the like), and can be independently used for receiving and sending the Beidou short message. The terminal device further comprises a text module, an audio module, an image module and the like to acquire different types of data. After the audio module, the image module and the text module acquire the corresponding types of original data, the original data is subjected to a built-in coding compression algorithm of the module, multi-source heterogeneous target data is finally output, the terminal equipment performs normalized coding processing on the multi-source heterogeneous target data, namely, the multi-source heterogeneous target data is processed through a central processing module, a sub-packet data frame with a unified data coding structure is obtained, and the sub-packet data frame is transmitted through a Beidou short message module.

When the terminal equipment is used as a receiving terminal, the received sub-packet data frames are processed through a decoding algorithm of normalized encoding, and the original data of different types such as texts, audios, images and the like are restored.

The terminal equipment can send to another terminal equipment or a back-end control center through the Beidou short message module. Similarly, the process of the background control center for data transceiving can be realized in the mode.

Fig. 3 is a schematic data flow diagram of a packetized data frame based on a beidou short message according to an embodiment of the present application. Referring to fig. 3, different types of data modules, such as a text data module, a graphic data module, an audio data module and other data modules, can process original data to obtain corresponding target data, such as text data, image compression data, audio coding data and other data, and output to obtain corresponding sub-packet data frames through two modules of normalization coding processing and information frame processing in a central processing unit, wherein the sub-packet data frames are packaged based on the Beidou short message, so that the obtained Beidou short message can be sent to a Beidou satellite through the Beidou short message module. Similarly, the receiving process is the inverse of the transmitting process, and the specific implementation can be referred to the above description, which is not repeated here.

Referring to fig. 4, fig. 4 shows an implementation schematic diagram of a data transmission method based on a beidou short message according to an embodiment of the present application, where the method includes the following steps:

In S401, a transmitting terminal generates a plurality of packetized data frames in response to a transmission request of target data; the packetized data frame includes a frame header portion and a data portion; the data part is generated according to a data format corresponding to the data type of the target data; the frame head part records the packetizing information of the packetizing data frame; the sub-packet data frame is based on Beidou short message encapsulation.

In this embodiment, when the transmitting terminal needs to transmit the target data through the beidou satellite, normalization encoding processing needs to be performed on the target data, so as to obtain a plurality of sub-packet data frames. The sub-packet data frame is obtained based on Beidou short message encapsulation. The packetized data frame specifically includes a frame header portion and a data portion. The frame header portion may be used to store packetization information for the packetized data frame, and the data portion may be used to record a data type of the target data and a data block associated with the target data.

Further, as another embodiment of the present application, fig. 5 shows a flowchart of a specific implementation of S401 provided in an embodiment of the present application. Referring to fig. 5, S401 in the embodiment of the present application may specifically include S4011 to S4013, compared with the embodiment of fig. 4, and specifically described as follows:

The frame header portion includes: a control field and a frame sequence number; the generating a plurality of packetized data frames in response to a request to send target data includes:

in S4011, the sending terminal divides the target data into a plurality of data blocks according to the maximum data size of a single sending corresponding to the beidou short message; the data amount of each of the data blocks is not greater than the maximum data amount.

In this embodiment, since the beidou short message has a length limitation, before the sending terminal encapsulates the target data into the packetized data frame, it needs to determine whether the data amount of the target data exceeds the maximum data stream that can be stored in the application data in the frame format, that is, whether the target data exceeds the length limitation. If so, the target data needs to be divided into more than two sub-packet data frames for transmission, and if not, the target data can be transmitted through one sub-packet data frame.

In one possible implementation manner, if the sending terminal needs to send two or more target data, and each target data is smaller than a preset length limit, the two or more target data may be subjected to packet combining processing, that is, the two target data may be encapsulated into a unified packet data frame. For example, if the maximum data size is 2MB and the data size of each target data is 0.5MB, 4 target data may be encapsulated in the same packetized data frame, so as to implement the packet transmission.

Illustratively, fig. 6 shows a logic schematic diagram of a target data packetization according to an embodiment of the present application. Referring to fig. 6, the logic for sending the packetization specifically includes the following steps:

step 1: the sending terminal encodes the acquired target data according to the frame structure of the sub-packet data frame to generate an overhead part of the frame structure and a data content part of the target data, wherein the total data of the two parts is specifically A bytes;

step 2: the transmitting terminal inquires the transmission upper limit of a single Beidou short message of the associated Beidou satellite, namely the maximum data size, specifically N bytes;

step 3: and if the sending terminal detects that A < = N, the target data can be sent through a single Beidou short message, otherwise, if A is larger than N, the terminal equipment packetizes the target data to obtain M packetized data frames, and the M packetized data frames are sent one by one according to the packetizing sequence numbers, namely the data packets 1-M are sent one by one.

In this embodiment, when the transmitting terminal recognizes that the target data needs to be packetized, the transmitting terminal may generate corresponding packetizing information and record the packetizing information in the header portion. Wherein the frame header portion includes a control field and a frame sequence number. And combining the data blocks obtained by analyzing the same frame sequence number so as to restore the corresponding target data.

Illustratively, table 1 shows a schematic diagram of a frame structure of a packetized data frame provided in an embodiment of the present application. As shown in table 1, the packet data frame includes the following five parts. The method comprises the steps of respectively starting an initiator, a frame head part, a data part, a frame tail and a terminator, wherein the contents of the parts are specifically as follows:

TABLE 1

1. Starter symbol

The initiator is used in particular to identify the start of a packetized data frame, and consists of an identifier and a separator.

1.1 identifier

The identifier represents the beginning of a packetized data frame, which may be, for example, a fixed value of $BDMMX, identifying the packetized data frame as a multi-source heterogeneous data message.

1.2 separator

The separator is used for content separation, and may be, for example, a comma (ASCII code 0x 2C) to inform that the content following the character is the actual content within the packetized data frame.

2. Frame header part

The frame header portion is used for identifying main information of the sub-packet data frame and comprises a control domain, sub-packet information, a frame sequence number and a length domain L

2.1 control Domain

The control field consists of 1 byte, and is encoded by BIN.

SUB packet identification: marking whether the target data has SUB-packets, sub=0 not SUB-packets, sub=1 SUB-packets; that is, when A corresponding to the target data is equal to or less than N, the SUB is 0, and when A > N of the target data, the SUB is 1.

BGP start packet: sub=1, bgp=1 marks the packetized data frame as a start packet, and bgp=0 marks the packetized data frame as not a start packet; when sub=0, bgp=0, i.e., there is no need to distinguish between the start packet and the end packet;

EDP end packet: sub=1, edp=1 marks the packetized data frame as an end packet, and edp=0 marks the packetized data frame as not an end packet; when sub=0, edp=0, i.e., there is no need to distinguish between the start packet or the end packet;

ACK feedback mode: because the Beidou short message has a certain packet loss rate, in order to ensure the integrity of target data, aiming at partial type target data, a receiving terminal needs to confirm whether packet loss occurs or not, namely 0 represents that the receiving terminal does not need to make feedback, a transmitting terminal only takes charge of transmitting, and the target data is deleted from a queue after the transmitting terminal finishes transmitting the target data; and 1 represents that the receiving terminal needs to feed back the received target data, and the target data is recorded in the queue after being sent, and is deleted after the receiving terminal confirms that the target data is received.

The FUN function code is defined as shown in Table 2, wherein when the function code is 0, the packet data frame is not used for transmitting data, but is used for carrying out acknowledgement. For example, the transmitting terminal transmits a packet data frame with ACK 1 to the receiving terminal. After receiving the target data, the receiving terminal may feed back a feedback frame with the function code 1 to the transmitting terminal, so as to inform the transmitting terminal that the target data has been received. When the function code is 1, that is, the first bit value is the first bit value, the sub-packet data frame is specifically used for transmitting multi-source heterogeneous application data; and when the function code is 2, namely the second bit value, the sub-packet data frame is a packet loss feedback data frame.

TABLE 2

2.2 subcontracting information

The length of the packetization information is 2 bytes, and as shown in table 2, the packet sequence number corresponding to the packetized data frame is identified by BIN encoding, so that 65535 packetization can be split maximally.

D7

D6

D5

D4

D3

D2

D1

D0

D15

D14

D13

D12

D11

D10

D9

D8

TABLE 3 Table 3

The control domain judges that the packetizing mark is 1, which indicates that the packet exists when the packet is packetized, and the content carried in the packetizing information is omitted when the packet is not packetized.

2.3 frame sequence number

The frame sequence number length is 2 bytes, BIN coding is adopted as the data number of the target data, namely the unique identification of the target data, if the target data exists as a sub-packet message, the sub-packet data frames split by the same target data have the same corresponding frame sequence number.

When the number of the target data increases, for example, two text data are transmitted, the frame sequence number can be increased, the transmitting terminal sequentially increases the frame sequence number according to the transmitting sequence of the target data, and the receiving terminal can continuously judge whether to lose the packet according to whether the frame sequence number. Maximum support 65535, reset to 0 and restarted after maximum is reached.

2.4 Length Domain L

The length field L consists of 2 bytes and is encoded with BIN as shown in table 4.

D7

D6

D5

D4

D3

D2

D1

D0

D15

D14

D13

D12

D11

D10

D9

D8

TABLE 4 Table 4

The data length L is a byte total number of user data using BIN encoding.

3. Data part

The part is specifically used for storing the data blocks obtained by dividing the target data.

4. Frame check field

The frame check field may be a check field obtained by cyclic redundancy check (Cyclic Redundancy Check, CRC), or may be generated by other check techniques, where the frame check field is specifically 2 bytes, and is used for checking other contents except for a start symbol, an end symbol and a frame tail portion in a packet data frame, and the check algorithm may be agreed with a transmitting terminal and a receiving terminal together, and is not limited herein.

5. End symbol

The terminator marks the end of a packetized data frame. The fixed value is < CR > < LF >, the contents of which can be expressed in various forms as in table 5.

Character(s)	Hexadecimal system	Decimal system	Remarks
				<CR>	0D	13	Carriage return
<LF>	0A	10	Line feed

TABLE 5

In S4012, the transmitting terminal adds each of the data blocks to the data portion in the preset frame template, respectively.

In this embodiment, after the transmitting terminal divides the target data into a plurality of data blocks, the data blocks may be stored in the data portion described above. The data part comprises two parts, namely a data type part and a data content part. The sending terminal sets a data type identifier according to the data type of the target data.

In S4013, the transmitting terminal sets the function code of the control field in the preset frame template to which the data block is added to a first bit value, and sets the frame sequence number to a sequence number corresponding to the target data, and generates the plurality of packetized data frames.

In this embodiment, when the transmitting terminal needs to transmit multi-source heterogeneous data, the function code of the control domain may be set to a first bit value, as described above, may be set to 1, and frame sequence numbers corresponding to all packets (i.e. a plurality of packet data frames) in the target data may be uniformly set to the same value, where the value is the same as the sequence number of the target data.

The generation of the packet data frame can be divided into the following four cases according to the different data types of the target data:

case 1: text type target data

And if the data type of the target data is a text type, setting a data type identifier in the data part as a first bit value, setting an encryption field of the data part according to the encryption mode of the target data, and adding the data block into a character data field of the data part.

In this embodiment, when the target data is text type data, the format of the data portion thereof may be specifically shown in table 6.

TABLE 6

Data type identification (first bit value corresponding to text type): 1 byte, a fixed value of 0x01, i.e., a first bit value, when the data type identifier of 0x01 indicates that the data type corresponding to the target data is a text type.

Encryption mode: 1 byte, and identifies the encryption mode corresponding to the text character data, for example, different bit values of the byte can correspond to different encryption modes, which is specifically as follows: when the encryption mode is 0x00, the method is expressed as plaintext and is not encrypted; when the encryption mode is 0x06, the text character data is encrypted by AES; when the encryption mode is 0x07, the text character data is encrypted by DES; when the encryption scheme is 0x08, text character data is encrypted by using the cryptographic sm 4.

Text character data: text character originals (i.e., data blocks) or data after encrypting a data block.

Case 2: image type target data

And if the data type of the target data is the image type, setting the data type identifier as a second bit value, setting a format field of a data part according to the compression mode of the target data, and adding the data block into a pixel data field of the data part.

In this embodiment, the beidou short message terminal supports uploading of target data of an image type, the picture format data is usually larger and is difficult to transmit by using a single short message, so that the target data of the image type can be encoded and compressed before packetizing, and after receiving a packetized data frame, the receiving terminal can restore the encoded data through progressive decoding to obtain corresponding target data.

When the target data is image type data, the format of the data portion thereof may be specifically shown in table 7.

TABLE 7

Data type identification (first bit value corresponding to image type): 1 byte, a fixed value of 0x02, i.e., a second bit value, when the data type identifier of 0x02 indicates that the data type corresponding to the target data is an image type.

The format field includes two parts of picture format and coding compression mode.

Picture format: a 1 byte, illustratively, when the content of the byte is 1, indicates that the image is in BPM format, and when the content of the byte is 2, indicates that the image is in JPG format.

Encoding and compressing: a 1 byte, illustratively, when the content of the byte is 1, indicates that the picture is algorithmically encoded and compressed, illustratively, when the content of the byte is 0, indicates that the picture is not encoded and compressed.

Content information after picture coding: the data blocks of the picture data after algorithm coding can be split and packetized in any length, and progressive decoding and restoring can be carried out.

Case 3: target data of audio type

And if the data type of the target data is the audio type, setting the data type identifier as a third bit value, setting an encoding field of a data part according to the encoding code rate of the target data, and adding the data block into the audio data field of the data part.

In this embodiment, the beidou short message terminal supports uploading of audio type target data, audio format data is usually larger and is difficult to transmit by using a single short message, so that encoding compression can be performed through an algorithm, and decoding reduction can be performed on the compressed data; the code rate selected by the coding is to select the highest coding rate under the condition that the coded data does not exceed the maximum range of the current Beidou short message.

When the target data is audio type data, the format of the data portion thereof may be specifically shown in table 8.

TABLE 8

Data type identification (third bit value corresponding to audio type): 1 byte, a fixed value of 0x03, i.e., a third bit value, when the data type identifier of 0x03 indicates that the data type corresponding to the target data is an audio type.

Coding rate: 1 byte, alternatively, in order to reduce the length of the byte, a value obtained by dividing an actual coding rate by 10 may be used as a value of the coding rate, and the code rate common values include 2400, 1200, 700, and 450.

Encoding and compressing: 1 byte, 1 represents that the audio is subjected to algorithm coding compression, and 0 represents that the audio is not subjected to coding compression;

audio encoded content information: and the data blocks obtained by dividing the target data are subjected to algorithm coding.

Case 4: other types of target data

In this embodiment, the frame format of the beidou short message also reserves the format for uploading other types of data messages, and the sending terminal is only responsible for data transmission, so that the receiving terminal can parse by itself. When the target data is other types of data, the format of the data portion thereof may be specifically shown in table 9.

TABLE 9

Data type identification (fourth bit value corresponding to other types): 1 byte, a fixed value of 0x04, i.e., a fourth bit value, when the data type identifier of 0x04 indicates that the data type corresponding to the target data is other types.

Other data content information: and transmitting byte array data without format requirements, and analyzing by the receiving terminal.

In one possible implementation, the compression identifier and the encryption identifier may be added by reducing the start packet and end packet parameters in the control domain, which is defined as follows:

compression identifier ZIP: zip=0: indicating that the data content in the packetized data frame is not compressed by the compression algorithm; zip=1: representing the compression of the data content in the packetized data frames by a compression algorithm;

encryption identification ESAM: esam=0: indicating that the data content in the packetized data frame is not encrypted by an encryption algorithm; esam=1: the data content in the data frame of the representation package is encrypted by an encryption algorithm;

in one possible implementation, the maximum packet number information may be added to the packetization information, taking up 2 bytes.

The two implementation modes increase control parameters such as compression, encryption and the like, so that a receiver can obtain the total number of packets without waiting for an end packet and receiving a first packet, the packet missing and missing pre-statistics processing can be started before the end packet is received, the sequence number of the missing packet can be accurately fed back when the packet is fed back and the processing efficiency is improved, but the byte number is increased in the two modes, the coding efficiency is low, and the resource consumption is increased when the receiver performs the packet missing pre-processing. Therefore, in the practical application process, the target data can be encoded and framed according to the practical requirements, which is different in how the encoding format makes a trade-off between encoding efficiency and transmission.

In the embodiment of the application, different bit values are set on the frame head part of the sub-packet data frame and the data type identification of the data part, so that the data format of the data part can be determined, the data is encapsulated according to the data format corresponding to the data type, the sub-packet data frame applicable to multi-source heterogeneous data is obtained, the normalization coding is carried out, and the data processing efficiency of the receiving terminal and the transmitting terminal is improved.

In S402, the transmitting terminal sequentially transmits the plurality of sub-packet data frames to the beidou satellite according to the sub-packet information of the plurality of sub-packet data frames, so as to forward the plurality of sub-packet data frames to the receiving terminal through the beidou satellite.

In this embodiment, when the target data is divided into a plurality of packet packets, that is, a plurality of packet data frames, each packet data frame may be sequentially transmitted to the satellite according to the packet sequence number carried in the packet information.

In S403, the beidou satellite sequentially sends the received several packet data frames to the receiving terminal.

In this embodiment, after receiving the packet data frame sent by the sending terminal, the beidou satellite may sequentially send the packet data frame to the corresponding receiving terminal according to the packet sequence number in the packet information.

In S404, the receiving terminal receives a plurality of sub-packet data frames forwarded by the Beidou satellite; the plurality of sub-packet data frames are sent to the Beidou satellite by the sending terminal; the plurality of packetized data frames including a frame header portion and a data portion; the sub-packet data frame is based on Beidou short message encapsulation.

In this embodiment, the receiving terminal may receive the packet data frame forwarded by the beidou satellite through the radio frequency module. The frame format of the packetized data frame may be referred to above, and will not be described herein.

In S405, the receiving terminal determines a data type corresponding to the packetized data frame according to the data portion, and acquires a data format corresponding to the data type.

In this embodiment, after receiving the packetized data frame, the receiving terminal may determine a data type corresponding to the packetized data frame, that is, identify a data type identifier in the data portion, so as to determine a data type corresponding to the packetized data frame according to the data type identifier, and then acquire a data format corresponding to the data type.

Optionally, the receiving terminal may identify an acknowledgement identifier in the control domain of the frame header portion, i.e. the ACK identifier described above, so as to determine whether the acknowledgement data frame needs to be sent to the transmitting terminal after receiving the packetized data frame, and if so, set the function code of the frame header portion to a preset value.

Further, as another embodiment of the present application, the step S405 may specifically include the following steps:

step 1: and if the function code of the control domain in the frame header part is a first bit value, identifying the first byte of the data part as a data type identifier.

In this embodiment, if the function code of the control field of the frame header portion of the packetized data frame is the first bit value, it may be determined that the packetized data frame is used for transmitting the multi-source heterogeneous data packet. In this case, a first byte of the data portion may be read, the first byte identifying a data type for defining a data type of the target data.

Step 2: and if the data type identifier is a first bit value, extracting an encryption field from the data part, determining an encryption mode corresponding to a data block of the sub-packet data frame according to the encryption field, and processing the data block by the encryption mode to obtain text data.

In this embodiment, if the data type is identified as the first bit value, for example, 0x01, it indicates that the data type is the text type, and the data portion may be parsed in the data format as shown in table 6, so as to obtain the text data.

Step 3: if the data type identifier is a second bit value, the data type is an image type, a format field is extracted from the data part, an image format corresponding to a data block of the sub-packet data frame is determined according to the format field, and the data block is processed through the image format to obtain pixel data;

in this embodiment, if the data type is identified as the second bit value, for example, 0x02, it indicates that the data type is the image type, and the data portion may be parsed in the data format as shown in table 7, so as to obtain the image data.

Step 4: and if the data type identifier is a third bit value, the data type is an audio type, a coding field is extracted from the data part, a coding code rate corresponding to a data block of the sub-packet data frame is determined according to the coding field, and the data block is processed through the coding code rate to obtain audio data.

In this embodiment, if the data type is identified as the third bit value, for example, 0x03, it indicates that the data type is the audio type, and the data portion may be parsed in the data format shown in table 8, so as to obtain the audio data.

Step 5: if the data type identifier is a fourth bit value, the data type is of other types, and the data block of the sub-packet data frame is processed through a preset analysis algorithm to obtain other data;

In this embodiment, if the data type identifier is the fourth bit value, for example, 0x04, it indicates that the data type is other types, and the receiving terminal performs self-analysis.

And the text data, the image data, the audio data and the other data are used for synthesizing the target data.

In S406, the receiving terminal parses the plurality of packetized data frames based on the data format to obtain target data.

In this embodiment, after receiving the packetized data frame corresponding to the same frame sequence number, the receiving terminal may combine all the data blocks with the same frame sequence number to obtain the target data.

As can be seen from the foregoing, in the packet loss response method based on the beidou short message provided by the embodiment of the present application, when a transmitting terminal needs to forward application data carrying a certain type through a beidou satellite, a data type corresponding to the application data is determined, a data format of a data part in a packet data frame is determined by the data type, and target data is encapsulated through a frame template corresponding to the data format, so as to obtain a plurality of packet data frames, wherein a frame header part in the packet data frame records packet information of each packet data frame, and a transmitting terminal can sequentially transmit the plurality of packet data frames to the beidou satellite through the packet information, so as to achieve the purpose of data forwarding through the beidou satellite. Compared with the existing satellite message technology, the sub-packet data frame in the Beidou short message is a frame format compatible with different formats, namely, for different types of data, the sub-packet data frame comprises a frame header part and a data part, the data part can be subjected to self-definition setting according to the data format, a sending terminal does not need to configure a new frame template for the different types of data, and can process the data by adopting a normalized coding technology and a framing technology, so that the processing difficulty of the sending terminal and a receiving terminal to the Beidou short message is greatly reduced, and the communication efficiency is improved.

On the other hand, after receiving the sub-packet data frame, the packet loss identification method based on the Beidou short message provided by the embodiment of the application can determine the data type of the sub-packet data frame through the frame header part, analyze and identify the content of each byte of data in the data part through the corresponding data format, so as to obtain the data block packaged in the sub-packet data frame, and combine the data blocks obtained by analyzing the sub-packet data frame to obtain the target data sent by the sending terminal, and can also decode by adopting the normalized coding technology and the framing technology, so that the processing difficulty of the sending terminal and the receiving terminal to the Beidou short message is greatly reduced, and the communication efficiency is further improved.

Further, as another embodiment of the present application, fig. 7 shows a flowchart of an implementation of a packet loss response method based on a beidou short message according to another embodiment of the present application. Referring to fig. 7, compared with the embodiment of fig. 4, in the packet loss response method based on the beidou short message provided in the embodiment of the present application, before S406, the method may further include: s701 to S708 are specifically described as follows:

In S701, if the receiving terminal detects that the received packet data frames meet a preset packet loss condition, generating a packet loss feedback data frame; the function code of the control domain in the frame head part of the packet loss feedback data frame is a second bit value; the packet loss feedback data frame comprises at least one packet loss feedback information.

In this embodiment, the receiving terminal may perform packet loss detection on the received packet data frame, and if it is detected that the frame sequence number or the packet sequence number of the received packet data frame meets a preset packet loss condition, a packet loss feedback data frame may be generated to request the transmitting terminal to retransmit the packet data frame with lost packets, so as to improve the validity of data transmission.

In one possible implementation manner, the frame tail part of the sub-packet data frame is used for storing a frame check field, the receiving terminal can check the data content of the sub-packet data frame through the frame check field after receiving the sub-packet data frame, and if the data content is within a preset self-correction range, the receiving terminal corrects the content through the frame check field; otherwise, if the content of the data error is out of the self-correction range, the erroneous sub-packet data frame is identified as a lost sub-packet data frame, and the sub-packet sequence number corresponding to the sub-packet data frame is recorded in the packet loss feedback data frame.

The data packet loss specifically may include the following three cases:

case 1: partial packet loss

If the data tail frames of the packet data frames are received and at least two packet data frames with discontinuous packet sequence numbers exist in the packet data frames, determining a first packet loss sequence number of packet loss according to the at least two packet data frames with discontinuous packet sequence numbers, and generating specified sequence number packet loss feedback based on the first packet loss sequence number; the packet loss batch and the packet loss mark in the specified sequence number packet loss feedback are determined based on the first packet loss sequence number; and the packet loss type in the packet loss feedback of the designated sequence number is a first bit value.

In this embodiment, the receiving terminal does not receive all the packets within a preset valid waiting time, and receives the end data packet, that is, the end packet in the control domain of the frame header part in the received packet data frame is valid, and recognizes that the data end frame corresponding to a plurality of packet data frames is received. In this case, the receiving terminal may determine a first packet loss sequence number corresponding to the lost packet data frame according to a plurality of packet data frames with discontinuous packet sequence numbers, and generate a corresponding packet loss feedback with a designated sequence number according to the first packet loss sequence number. The data frame format of the designated sequence number packet loss feedback is the same as the multi-source heterogeneous data frame format, and can be seen in table 1. The difference is that the data portion in the data frame format of the specified packet loss feedback is different from the data portion in the multi-source heterogeneous data.

Illustratively, the format of the data portion in the specified packet loss feedback may be as shown in table 10.

Table 10

Frame packet loss type: used for distinguishing different packet loss conditions. When the frame packet loss type is the first bit value, for example, 0x01, the packet loss feedback data frame is identified as the packet loss feedback with the designated sequence number.

Frame sequence number: and 2 bytes, which is used for determining the frame sequence number of the target data corresponding to the packet data frame of the lost packet.

Frame packet loss batch: the frame loss packet is divided into a batch according to 32 marks, for example, the packet sequence is 1-32 as a first batch, the packet sequence is 33-64 as a second batch, and so on, and the first packet loss sequence number, namely the packet loss packet sequence number, is determined through the packet loss batch and the packet loss mark. For example, the first packet loss sequence number may be determined by multiplying the packet loss lot by the byte corresponding to the packet loss flag.

Frame packet loss flag: the packet loss mark is 4 bytes, and whether packet loss occurs in the 1 st packet to the 32 nd packet is marked according to the bit. And setting the value corresponding to the packet loss mark with packet loss to 1, so that a plurality of first packet loss serial numbers can be marked at one time.

TABLE 11

Case 2: tail packet data loss

If the data tail frames of the packet data frames are not received within the preset waiting time, determining a second packet loss sequence number in the packet data frames, and generating tail packet loss feedback based on the second packet loss sequence number; the second packet loss data is the maximum value of the packet sequence number in the packet data frame; and the packet loss type field in the last packet loss feedback is a second bit value.

In this embodiment, the receiving terminal receives a part of the packetized data frame with a certain frame sequence number, but does not receive the end data packet corresponding to the frame sequence number within a preset valid waiting time, that is, does not receive the data packet with the valid end packet in the control domain of the frame header part in the packetized data frame, and at this time, the receiving terminal determines that the data end frame corresponding to the frame sequence number is lost. In this case, the receiving terminal may determine that the packet sequence number is the largest as the second packet loss sequence number among all the packet data frames received with respect to the frame sequence number, and generate the corresponding last packet loss feedback according to the second packet loss sequence number. The data frame format of the last packet loss feedback is the same as that of the multi-source heterogeneous data frame format, and can be seen in table 1. The difference is that the data portion in the data frame format of the end packet loss feedback is different from the data portion in the multi-source heterogeneous data.

Illustratively, the format of the data portion in the specified packet loss feedback may be as shown in table 12.

Description of the invention	Number of bytes
		Frame packet loss type	1
Frame sequence number	2
		Packet sequence number	2

Table 12

Frame packet loss type: used for distinguishing different packet loss conditions. When the frame packet loss type is a second bit value, for example, 0x02, the packet loss feedback data frame is identified as the last packet loss feedback;

Frame sequence number: frame sequence number of packet loss frame.

Packet sequence number: and finally, the received sub-packet sequence number is the second packet loss sequence number.

Under the condition of packet loss at the end, the receiving terminal cannot confirm the specific lost data packet, so that the receiving terminal can feed back the last received packet sequence number, namely the packet sequence number with the largest value, to the transmitting terminal, so that the transmitting terminal can transmit all the packet data frames after the second packet sequence number.

Case 3: all packetization loss of target data

In this embodiment, when the transmitting terminal needs to transmit a plurality of continuous target data to the receiving terminal, for example, a plurality of continuous images, the frame sequence numbers corresponding to the plurality of continuous target data are continuous, and therefore if there is a discontinuity in the frame sequence numbers in the received packet data frames, in this case, it can be determined that there is a case where all packets related to the target data are lost. At this time, one entire frame packet loss feedback may be generated. The whole frame packet loss feedback can carry a lost frame sequence number, and the packet loss type is set to be a third bit value. The data frame format of the whole frame packet loss feedback is the same as that of the multi-source heterogeneous data frame format, and can be seen in table 1. The difference is that the data part in the data frame format of the whole frame packet loss feedback is different from the data part in the multi-source heterogeneous data.

Illustratively, the format of the data portion in the entire frame packet loss feedback may be as shown in table 13.

Description of the invention	Number of bytes
		Frame packet loss type	1
Frame sequence number	2

TABLE 13

Frame packet loss type: used for distinguishing different packet loss conditions. When the frame packet loss type is the third bit value, for example, 0x03, the packet loss feedback data frame is identified as the whole frame packet loss feedback.

Frame sequence number: frame sequence number of packet loss frame.

In the embodiment of the application, the receiving terminal can generate different packet loss feedback data frames according to different packet loss conditions, so that the transmitting terminal can retransmit according to the packet loss conditions. Compared with the existing packet loss retransmission technology, the embodiment of the application does not need to send all the sub-packet data frames again according to the sub-packet sequence numbers in sequence, and the next target data is sent after the target data of the whole frame is obtained without restoration, but can send corresponding packet loss retransmission through different types of packet loss feedback data frames, so that the communication efficiency can be improved.

In S702, the receiving terminal sends the packet loss feedback data frame to the beidou satellite, so as to forward the packet loss feedback data frame to the sending terminal through the beidou satellite.

In this embodiment, the receiving terminal may send the packet loss feedback data frame to the beidou satellite so as to perform a subsequent packet loss retransmission procedure.

In S703, the beidou satellite sends the packet loss feedback data frame to the sending terminal.

In S704, if the sending terminal detects a response data frame fed back by the receiving terminal, the sending terminal acquires a function code of a control field in a frame header portion of the response data frame.

In this embodiment, the transmitting terminal may receive the response data frame forwarded by the beidou satellite. Wherein the frame format of the response data frame is the same as the frame format of the multi-source heterogeneous data frame. See, in particular, table 1. Unlike this, the function code may have a different bit value depending on the content of the response within the control field of the frame header portion of the response data frame. Therefore, in order to determine the response type corresponding to the response data frame, the function code needs to be identified.

In one possible implementation, if the function code is a third bit value, for example, 0x00, the acknowledgement data frame is acknowledgement or negative acknowledgement data of the message, and the sending terminal may be notified whether the receiving terminal receives the specified target data according to the value of the acknowledgement ACK in the data message.

In S705, if the transmitting terminal identifies the function code as the second bit value, the transmitting terminal identifies the response data frame as a packet loss feedback data frame.

In this embodiment, when the sending terminal detects that the function code is the second bit value, it indicates that the response data frame is specifically a packet loss data frame, and needs to identify the packet loss type of the response data frame and resend the packet loss sub-packet data frame.

In S706, the transmitting terminal parses the packet loss feedback data frame based on the packet loss feedback frame format, and determines a packet loss data frame.

In this embodiment, the transmitting terminal may analyze the packet loss feedback data frame, determine the frame sequence number and the packet sequence number of the packet loss data frame at the receiving terminal side, thereby determining the packet loss or error packet loss data frame in the transmission process, and identify the packet loss data frame corresponding to the frame sequence number and the packet sequence number as the packet loss data frame.

Further, as another embodiment of the present application, the above manner of determining the packet loss data frame is specifically:

step 1: the sending terminal reads a first byte of a data part in the packet loss feedback data frame and determines the number of packet loss feedback information contained in the packet loss feedback data frame; each packet loss feedback information is used for determining at least one lost or erroneous packetized data frame.

In this embodiment, the data format of the data portion in the packet loss feedback data frame is the first byte, which is used to limit the number of packet loss feedback information contained in the data portion, and the subsequent content is the specific content of each packet loss feedback information. According to the different types of the packet loss feedback information, one packet loss feedback information can specifically correspond to at least one sub-packet data frame.

Illustratively, table 14 shows a schematic format of a packet loss feedback data frame according to an embodiment of the present application. Referring to table 14, a packet loss feedback data frame may carry multiple packet loss feedback information at the same time, that is, the data portion of the packet loss feedback data frame records: the information number of the packet loss feedback information. For example, the packet loss feedback data frame includes n packet loss feedback information, each packet loss feedback information is sequentially read, and the corresponding packet loss data frame is determined according to the packet loss feedback information.

TABLE 14

Step 2: and sequentially acquiring the packet loss feedback information from the data part in the packet loss feedback data frame.

In this embodiment, the corresponding information lengths of the different types of packet loss feedback information are different. Therefore, the sending terminal device can sequentially read each piece of packet loss feedback information, and the corresponding information length is determined by determining the packet loss type of the packet loss feedback information. The information lengths of different packet loss types may be referred to in the related description of S701, and will not be described herein.

According to different types of packet loss feedback information, the following three situations can be classified:

case 1: and if the packet loss type field of the packet loss feedback information is a first bit value, for example, 0x01, identifying the packet loss feedback information as the packet loss feedback with the designated sequence number. The appointed sequence number packet loss feedback comprises a packet loss batch and a packet loss mark, and the sending terminal determines a first packet loss sequence number according to the packet loss batch and the packet loss mark carried in the appointed sequence number packet loss feedback and takes a sub-packet data frame corresponding to the first packet loss sequence number as the packet loss data frame. It should be noted that, the packet loss flag in the packet loss feedback with the specified sequence number may include a plurality of packet loss flags, so that the number of the determined first packet loss sequence numbers may also be a plurality of packet loss flags, so that a plurality of packet loss data frames can be identified simultaneously.

Case 2: if the packet loss type field of the packet loss feedback information is a second bit value, for example, 0x02, identifying the packet loss feedback information as the last packet loss feedback. And the end packet loss feedback carries the largest packet sequence number received by the receiving terminal, namely a second packet loss sequence number, and takes all packet data frames with the packet sequence number larger than the second packet loss sequence number as the packet loss data frames according to the second packet loss sequence number carried by the end packet loss feedback.

Case 3: if the packet loss type of the packet loss feedback information is a third bit value, for example, 0x03, identifying the packet loss feedback information as whole frame packet loss feedback. Since the whole frame packet loss feedback is used for notifying the sending terminal that all the sub-packet data frames with the frame sequence number are lost, the sending terminal can identify all the sub-packet data frames with the frame sequence number being the designated sequence number as the packet loss data frames.

In the embodiment of the application, the packet loss feedback data frames are received, so that the plurality of packet loss feedback information carried in the packet loss feedback data frames are determined, and all the packet loss data frames can be uniformly retransmitted to the receiving terminal, so that the communication efficiency can be improved.

In S707, the transmitting terminal retransmits the packet loss data frame to the beidou satellite, so as to transmit the packet loss data frame to the receiving terminal through the beidou satellite.

In S708, the beidou satellite transmits the packet loss data frame to the receiving terminal.

In this embodiment, for a packet loss data frame with a packet loss, the transmitting terminal will send the packet loss data frame to the beidou satellite again, and after receiving the packet loss data frame, the beidou satellite will forward the packet loss data frame to the receiving terminal so as to respond to the packet loss abnormal event, so that the receiving terminal can receive all the packet data frames to restore to obtain corresponding target data.

In the embodiment of the application, the bit value capable of carrying out packet loss feedback is set at the function code of the frame head part of the packet data frame, so that the feedback of packet loss information by adopting the same frame format can be realized, the consistency of the Beidou short message format can be improved, the packet loss response can be realized, the sending terminal only needs to send the packet data frame of packet loss again, and all packets in the whole frame without distinction are resent, so that the communication efficiency is further improved.

Fig. 8 is a block diagram of a packet loss response device based on a beidou short message according to an embodiment of the present invention, where each unit included in the packet loss response device based on a beidou short message is configured to execute each step implemented by a sending terminal in the embodiment corresponding to fig. 4. Please refer to fig. 2 and the related description of the embodiment corresponding to fig. 2. For convenience of explanation, only the portions related to the present embodiment are shown.

Referring to fig. 8, the packet loss response device based on the beidou short message includes:

a response data frame receiving unit 81, configured to obtain a function code of a control field in a frame header portion of a response data frame if the response data frame fed back by a receiving terminal is received;

The packet loss feedback identifying unit 82 is configured to identify the response data frame as a packet loss feedback data frame if the function code is a second bit value;

a packet loss parsing unit 83, configured to parse the packet loss feedback data frame based on a packet loss feedback frame format, and determine a packet loss data frame;

the packet loss sending unit 84 is configured to send the packet loss data frame to a beidou satellite again, so that the beidou satellite sends the packet loss data frame to a receiving terminal.

Optionally, the response device further includes:

a packet data frame transmitting unit for generating a plurality of packet data frames in response to a transmission request of the target data; the packetized data frame includes a frame header portion and a data portion; the data part is generated according to a data format corresponding to the data type of the target data; the frame head part records the packetizing information of the packetizing data frame; the sub-packaging data frame is packaged based on Beidou short messages; the sub-packaging data frame supports multi-element heterogeneous data coding;

and the sub-packet sending unit is used for sequentially sending the sub-packet data frames to the Beidou satellite according to the sub-packet information of the sub-packet data frames so as to forward the sub-packet data frames to the receiving terminal through the Beidou satellite.

Optionally, the frame header portion includes: a control field and a frame sequence number; the packetized data frame transmitting unit includes:

the packetized data frame transmitting unit includes:

the maximum data volume comparison unit is used for dividing the target data into a plurality of data blocks according to the maximum data volume of single transmission corresponding to the Beidou short message; the data amount of each data block is not greater than the maximum data amount;

a data block adding unit, configured to add each data block to the data portion in a preset frame template;

and the encoding unit is used for setting the function codes of the control domains in the preset frame template added with the data blocks as a first bit value, setting the frame serial numbers as serial numbers corresponding to the target data and generating the plurality of sub-packet data frames.

Optionally, the data block adding unit includes:

a text adding unit, configured to set a data type identifier in the data portion as a first bit value if the data type of the target data is a text type, set an encryption field of the data portion according to an encryption mode of the target data, and add the data block to a character data field of the data portion;

An image adding unit, configured to set the data type identifier to a second bit value if the data type of the target data is an image type, set a format field of a data portion according to a compression mode of the target data, and add the data block to a pixel data field of the data portion;

an audio adding unit, configured to set the data type identifier to a third bit value if the data type of the target data is an audio type, set an encoding field of a data portion according to an encoding code rate of the target data, and add the data block to an audio data field of the data portion;

and the other adding unit is used for setting the data type identifier to a fourth bit value and adding the data block to an application data field of the data part if the data type of the target data is other types.

Optionally, the packet loss parsing unit 83 includes:

the packet loss information number determining unit is used for reading a first byte of a data part in the packet loss feedback data frame and determining the number of packet loss feedback information contained in the packet loss feedback data frame; each piece of packet loss feedback information is used for determining at least one lost or erroneous sub-packet data frame;

The packet loss information reading unit is used for sequentially acquiring each packet loss feedback information from the data part in the packet loss feedback data frame;

the appointed sequence number packet loss feedback unit is used for identifying the packet loss feedback information as appointed sequence number packet loss feedback if the packet loss type field of the packet loss feedback information is a first bit value;

the first packet loss sequence number determining unit is used for determining a first packet loss sequence number according to the packet loss batch and the packet loss mark carried in the packet loss feedback of the designated sequence number, and taking a sub-packet data frame corresponding to the first packet loss sequence number as the packet loss data frame;

the last packet loss feedback unit is used for identifying the packet loss feedback information as last packet loss feedback if the packet loss type field is a second bit value;

the second packet loss sequence number determining unit is used for taking all the packet data frames with the packet sequence numbers larger than the second packet loss sequence number as the packet loss data frames according to the second packet loss sequence number carried by the last packet loss feedback; the second packet loss sequence number is the maximum value of the packet sequence numbers in the packet data frames received by the receiving terminal;

and the whole-frame packet loss feedback unit is used for identifying the packet loss feedback information as whole-frame packet loss feedback if the packet loss type is a third bit value, and identifying the plurality of sub-packet data frames as the packet loss data frames.

Therefore, the data transmitting device based on the Beidou short message provided by the embodiment of the invention can generate the corresponding packet loss feedback data frame when the receiving terminal detects that the packet loss exists, the function code of the control domain in the frame header part of the packet loss feedback data frame is the second bit value, the packet loss feedback data frame and the sub-packet data frame transmitted by the transmitting terminal adopt the same frame format and are the Beidou short message generated by supporting the multi-element heterogeneous data coding, therefore, the transmitting terminal can identify the function code when receiving the response data frame transmitted by the receiving terminal, and can determine the function code as the packet loss feedback data frame when detecting that the function code is the second bit value, determine the lost packet loss data frame and transmit the lost packet loss data frame to the receiving terminal again through the Beidou satellite, thereby realizing the response to the packet loss. Compared with the existing packet loss response technology, the method and the device have the advantages that when packet loss occurs, all packet-divided data frames of the whole frame of target data are not sent to the receiving terminal, and the designated packet-lost data frames can be sent to the receiving terminal by analyzing the packet loss feedback data frames, so that unnecessary sending operation is reduced; on the other hand, the data frame format adopted by the transmitting terminal is the same as the frame format of the packet loss feedback data frame transmitted by the receiving terminal, so that the purpose of multi-source heterogeneous coding can be realized, and the receiving terminal and the transmitting terminal can adopt a unified coding technology and decoding technology to code and decode different types of data, thereby greatly reducing the difficulty of decoding and coding and further reducing the pressure of data processing.

It should be understood that, in the block diagram of the packet loss response device based on the beidou short message shown in fig. 8, each module is configured to execute each step in the embodiments corresponding to fig. 4 to 7, and each step in the embodiments corresponding to fig. 4 to 7 has been explained in detail in the foregoing embodiments, and specific reference is made to fig. 4 to 7 and related descriptions in the embodiments corresponding to fig. 4 to 7, which are not repeated herein.

Fig. 9 is a block diagram of a packet loss identifying device based on a beidou short message according to an embodiment of the present invention, where each unit included in the packet loss responding device based on the beidou short message is configured to execute each step implemented by a receiving terminal in the embodiment corresponding to fig. 4. Please refer to fig. 2 and the related description of the embodiment corresponding to fig. 2. For convenience of explanation, only the portions related to the present embodiment are shown.

Referring to fig. 9, the packet loss response device based on the beidou short message includes:

a packet data frame receiving unit 91, configured to receive a plurality of packet data frames forwarded by the beidou satellite; the plurality of sub-packet data frames are sent to the Beidou satellite by the sending terminal; the plurality of packetized data frames including a frame header portion and a data portion; the sub-packaging data frame is packaged based on Beidou short messages; the sub-packaging data frame supports multi-element heterogeneous data coding;

A data format determining unit 92, configured to determine a data type corresponding to the packetized data frame according to the data portion, and obtain a data format corresponding to the data type;

a packet loss response unit 93, configured to generate a packet loss feedback data frame if the received packet loss data frames meet a preset packet loss condition; the function code of the control domain in the frame head part of the packet loss feedback data frame is a second bit value; the packet loss feedback data frame comprises at least one packet loss feedback information;

the packet loss feedback information sending unit 94 is configured to send the packet loss feedback data frame to the beidou satellite, so that the packet loss feedback data frame is forwarded to the sending terminal through the beidou satellite;

and the packet loss receiving unit 95 is configured to receive a packet loss data frame fed back by the beidou satellite based on the packet loss feedback data frame.

Alternatively, the data format determining unit 92 includes:

a function code identification unit, configured to identify a first byte of the data portion as a data type identifier if a function code of a control field in the frame header portion is a first bit value;

the text analysis unit is used for extracting an encryption field from the data part if the data type identifier is a first bit value and the data type corresponding to the sub-packet data frame is a text type, determining an encryption mode corresponding to a data block of the sub-packet data frame according to the encryption field, and processing the data block by the encryption mode to obtain text data;

The image analysis unit is used for extracting a format field from the data part if the data type identifier is a second bit value, determining an image format corresponding to a data block of the sub-packet data frame according to the format field, and processing the data block through the image format to obtain pixel data;

the audio analysis unit is used for extracting an encoding field from the data part if the data type identifier is a third bit value, determining an encoding code rate corresponding to a data block of the sub-packet data frame according to the encoding field, and processing the data block through the encoding code rate to obtain audio data;

the other analysis unit is used for processing the data blocks of the sub-packet data frame through a preset analysis algorithm to obtain other data if the data type is marked as a fourth bit value and the data type is other types;

Optionally, the packet loss feedback information includes: designating sequence number packet loss feedback, end packet loss feedback and whole frame packet loss feedback;

The packet loss response unit includes:

the specified sequence number packet loss determining unit is used for determining a first packet loss sequence number of packet loss according to at least two sub-packet data frames with discontinuous sub-packet sequence numbers if the data tail frames of the sub-packet data frames are received and at least two sub-packet data frames with discontinuous sub-packet sequence numbers exist in the sub-packet data frames, and generating specified sequence number packet loss feedback based on the first packet loss sequence number; the packet loss batch and the packet loss mark in the specified sequence number packet loss feedback are determined based on the first packet loss sequence number; the packet loss type in the packet loss feedback of the appointed sequence number is a first bit value;

the last packet loss determining unit is used for determining a second packet loss sequence number in the plurality of sub-packet data frames if the data tail frames of the plurality of sub-packet data frames are not received within a preset waiting time, and generating last packet loss feedback based on the second packet loss sequence number; the second packet loss data is the maximum value of the packet sequence number in the packet data frame; the packet loss type field in the last packet loss feedback is a second bit value;

the whole frame packet loss determining unit is used for determining a lost frame sequence number according to the two packet data frames with discontinuous frame sequence numbers if the two packet data frames with discontinuous frame sequence numbers are received, and generating whole frame packet loss feedback based on the lost frame sequence numbers; and the packet loss type field of the whole frame packet loss feedback is a third bit value.

It should be understood that, in the block diagram of the packet loss identifying device based on the beidou short message shown in fig. 9, each module is configured to execute each step in the embodiments corresponding to fig. 4 to 7, and each step in the embodiments corresponding to fig. 4 to 7 has been explained in detail in the foregoing embodiments, and specific reference is made to fig. 4 to 7 and related descriptions in the embodiments corresponding to fig. 4 to 7, which are not repeated herein.

Fig. 10 is a block diagram of a terminal device according to another embodiment of the present application. As shown in fig. 10, the terminal device 1000 of this embodiment includes: a processor 1010, a memory 1020 and a computer program 1030 stored in the memory 1020 and executable on the processor 1010, for example a program for a data transmission method based on Beidou short messages. The steps of each embodiment of the data transmission method based on the beidou short message described above, for example, the steps shown in fig. 4, are implemented by the processor 1010 when the computer program 1030 is executed. Alternatively, the processor 1010 may implement the functions of the modules in the embodiment corresponding to fig. 8, for example, the functions of the units 81 to 82 shown in fig. 8 and the functions of the units 91 to 93 shown in fig. 9 when the processor 1030 executes the computer program 1030, and refer to the related descriptions in the embodiment corresponding to fig. 8 and 9.

By way of example, computer program 1030 may be split into one or more modules that are stored in memory 1020 and executed by processor 1010 to complete the present application. One or more of the modules may be a series of computer program instruction segments capable of performing particular functions to describe the execution of computer program 1030 in terminal device 1000. For example, the computer program 1030 may be split into individual unit modules, each module functioning specifically as described above.

Terminal device 1000 can include, but is not limited to, a processor 1010, a memory 1020. It will be appreciated by those skilled in the art that fig. 10 is merely an example of terminal device 1000 and is not intended to limit terminal device 1000, and may include more or fewer components than shown, or may combine certain components, or different components, e.g., a terminal device may also include an input-output device, a network access device, a bus, etc.

The processor 1010 may be a central processing unit, or may be other general purpose processors, digital signal processors, application specific integrated circuits, off-the-shelf programmable gate arrays or other programmable logic devices, discrete hardware components, or the like. A general purpose processor may be a microprocessor or any conventional processor or the like.

Memory 1020 may be an internal storage unit of terminal device 1000, such as a hard disk or memory of terminal device 1000. Memory 1020 may also be an external storage device of terminal device 1000, such as a plug-in hard disk, smart memory card, flash memory card, etc. provided on terminal device 1000. Further, memory 1020 may also include both internal and external storage units of terminal device 1000.

The above embodiments are only for illustrating the technical solution of the present application, and are not limiting thereof; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.

Claims

1. The packet loss response method based on the Beidou short message is characterized by being applied to a sending terminal, and comprises the following steps:

2. The method for responding to packet loss according to claim 1, wherein the parsing the packet loss feedback data frame based on the packet loss feedback frame format, determining the packet loss data frame, comprises:

and sequentially acquiring the packet loss feedback information from the data part in the packet loss feedback data frame.

3. The method of claim 2, wherein sequentially obtaining the packet loss feedback information from the data portion in the packet loss feedback data frame includes:

if the packet loss type field of the packet loss feedback information is a first bit value, identifying the packet loss feedback information as packet loss feedback with a designated sequence number;

And determining a first packet loss sequence number according to the packet loss batch and the packet loss mark carried in the packet loss feedback of the designated sequence number, and taking a sub-packet data frame corresponding to the first packet loss sequence number as the packet loss data frame.

4. The method of claim 2, wherein sequentially obtaining the packet loss feedback information from the data portion in the packet loss feedback data frame includes:

according to the second packet loss sequence number carried by the last packet loss feedback, taking all the sub-packet data frames with the sub-packet sequence numbers larger than the second packet loss sequence number as the packet loss data frames; and the second packet loss sequence number is the maximum value of the packet sequence numbers in the packet data frames received by the receiving terminal.

5. The method of claim 2, wherein sequentially obtaining the packet loss feedback information from the data portion in the packet loss feedback data frame includes:

and if the packet loss type is a third bit value, identifying the packet loss feedback information as whole-frame packet loss feedback, and identifying a plurality of sub-packet data frames corresponding to the frame sequence numbers in the packet loss feedback information as the packet loss data frames.

6. The packet loss identification method based on the Beidou short message is characterized by being applied to a receiving terminal, and the receiving method comprises the following steps:

receiving a plurality of sub-packet data frames forwarded by a Beidou satellite; the plurality of sub-packet data frames are sent to the Beidou satellite by the sending terminal; the plurality of packetized data frames including a frame header portion and a data portion; the sub-packaging data frame is packaged based on Beidou short messages;

7. The method for identifying packet loss according to claim 6, wherein the packet loss feedback information includes: the packet loss feedback of the designated sequence number; and if the received plurality of sub-packet data frames meet a preset packet loss condition, generating a packet loss feedback data frame, including:

If the data tail frames of the packet data frames are received and at least two packet data frames with discontinuous packet sequence numbers exist in the packet data frames, determining a first packet loss sequence number of a packet loss according to the at least two packet data frames with discontinuous packet sequence numbers;

generating a specified sequence number packet loss feedback based on the first packet loss sequence number; the packet loss batch and the packet loss mark in the specified sequence number packet loss feedback are determined based on the first packet loss sequence number; and the packet loss type in the packet loss feedback of the designated sequence number is a first bit value.

8. The method for identifying packet loss according to claim 6, wherein the packet loss feedback information includes: the end packet loss feedback; and if the received plurality of sub-packet data frames meet a preset packet loss condition, generating a packet loss feedback data frame, including:

9. The method for identifying packet loss according to claim 6, wherein the packet loss feedback information includes: whole frame packet loss feedback; and if the received plurality of sub-packet data frames meet a preset packet loss condition, generating a packet loss feedback data frame, including:

10. A terminal device, characterized in that it comprises a memory, a processor and a computer program stored in the memory and executable on the processor, the processor executing the steps of the transmission method according to any one of claims 1 to 5 or the steps of the reception method according to any one of claims 6 to 9.

11. A computer readable storage medium storing a computer program, characterized in that the computer program when executed by a processor implements the steps of the transmission method according to any one of claims 1 to 5 or the steps of the reception method according to any one of claims 6 to 9.