CN109167652B - Short wave data transmission device, system and method in interference environment - Google Patents
Short wave data transmission device, system and method in interference environment Download PDFInfo
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- H—ELECTRICITY
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Abstract
The invention discloses a short wave data transmission device, a system and a method under an interference environment, which comprises a main control module and a data transmission module in communication connection with the main control module, wherein the main control module is used for data receiving and transmitting, data checking and link management; the data transmission module is used for unpacking the message content sent by the main control module and then preprocessing the message content before sending in the data sending process, and then sending the audio signal obtained by preprocessing before sending to the short wave radio station; the preprocessing before sending comprises channel coding, narrow-band signal modulation and digital-to-analog conversion; and the system is used for preprocessing the received audio signals after receiving in the data receiving process, packaging the data obtained by preprocessing after receiving and then sending the data to the main control module; the preprocessing after receiving comprises analog-to-digital conversion, signal demodulation and channel decoding. The invention can be suitable for application scenes with low requirement on transmission rate, and can stably maintain data transmission with lower rate in a strong interference environment.
Description
Technical Field
The invention relates to a short-wave data transmission scheme in an interference environment, and belongs to the technical field of short-wave communication.
Background
Interference of short-wave communication is roughly classified into natural interference and man-made interference. The natural interference is mainly caused by various environmental noises and the mutual influence of crowded short wave channels. Jamming is mainly classified into tracking jamming and broadband blocking jamming. After the tracking interference intercepts, sorts and analyzes the signals, the interference transmitter is guided to transmit aiming interference signals, the interference signals are concentrated in energy and large in interference intensity, the influence on communication is the greatest, and the communication frequency and the direction of the communication need to be intercepted accurately. The broadband blocking type interference adopts a high-power transmitter to block or pollute the communication frequency of the other party to the full-frequency-band signals, reduces the communication performance and achieves the purpose of interference. The natural interference caused by objective factors can only be weakened through technical measures, and the artificial interference can be countered or avoided by adopting effective measures and means.
The commonly used short-wave anti-interference communication means at present comprise frequency hopping communication, spread spectrum communication and high-power communication, wherein: frequency hopping communications can be resistant to tracking interference; spread spectrum communication has effects on both tracking interference and natural interference; the high-power communication has the effect of various interferences, but is only used for a large radio station, and the practical use has many limitations. The anti-interference means is suitable for use, short-wave communication can reach the transmission capability close to the normal environment, but the anti-interference means also has the defects of limited applicable environment and incapability of being supported by the conventional short-wave radio station.
Disclosure of Invention
In order to solve the above problems, the present invention provides a short-wave data transmission device, system and method in an interference environment, which are applicable to an application scenario with low requirement on transmission rate, and can stably maintain a low-rate data transmission in a strong interference environment.
The invention discloses a short wave data transmission device in an interference environment, which comprises a main control module and a data transmission module in communication connection with the main control module, wherein:
the main control module is used for data receiving and sending, data checking and link management;
the data transmission module is used for unpacking the message content sent by the main control module and then preprocessing the message content before sending in the data sending process, and then sending the audio signal obtained by preprocessing before sending to the short wave radio station; the preprocessing before sending comprises channel coding, narrow-band signal modulation and digital-to-analog conversion; and the system is used for preprocessing the received audio signals after receiving in the data receiving process, packaging the data obtained by preprocessing after receiving and then sending the data to the main control module; the preprocessing after receiving comprises analog-to-digital conversion, signal demodulation and channel decoding.
Specifically, the data transmission module is configured with:
a D/A converter for converting the modulated digital signal into an analog signal;
an A/D converter for converting an input analog signal into a digital signal; the FPGA is used for channel coding and decoding and is used as a buffer area among the A/D converter, the D/A converter and the digital signal processing module;
a digital signal processor for modulating and demodulating a narrowband based audio signal;
and the microprocessor is used for communicating with the serial port of the main control module, unpacking the received data packet sent by the main control module, and packing the data sent by the FPGA and then sending the data to the main control module.
The invention also discloses a short-wave data transmission system in an interference environment, which comprises a short-wave radio station and a short-wave data transmission device with the characteristics, wherein the short-wave radio station is connected and communicated with a data transmission module in the short-wave data transmission device through an audio interface; wherein:
the short wave radio station is used for converting the audio signals sent by the data transmission module into radio frequency signals and then transmitting the radio frequency signals to the opposite terminal, and converting the received radio frequency signals transmitted by the opposite terminal into audio signals and then transmitting the audio signals to the data transmission module.
The invention also discloses a short wave data sending method under the interference environment, which is based on the master control module, the data transmission module in communication connection with the master control module, and a short wave radio station connected with the data transmission module through an audio interface, and comprises the following steps:
the main control module sends a message sending request and starts a preset reply waiting timer;
the data transmission module replies whether to allow transmission according to the state of the data transmission module, when the data transmission module is in an idle state, the data transmission module replies to allow transmission, otherwise, the data transmission module replies to disallow transmission;
if the main control module does not receive a reply decision which is transmitted back by the data transmission module and allowed to be transmitted, the main control module transmits a message transmission request to the data transmission module again; if a reply decision which is transmitted back by the data transmission module and allows transmission is received in the waiting period, transmitting the message content to the data transmission module;
the data transmission module unpacks the message content sent by the main control module and then carries out preprocessing before sending, and then sends the audio signal obtained by preprocessing before sending to the short wave radio station; the preprocessing before sending comprises channel coding, narrow-band signal modulation and digital-to-analog conversion;
the short wave radio station converts the input audio signal into a radio frequency signal and then transmits the radio frequency signal to the opposite terminal.
As a preferred scheme, the packet includes a data packet and a confirmation packet, and if the packet content to be sent by the packet sending request is the data packet, the method further includes:
after the main control module sends the data message, a preset waiting confirmation timer is started, and a confirmation message containing a data message confirmation result sent by an opposite terminal is waited, wherein the confirmation result comprises ACK (acknowledgement character) or NACK (negative acknowledgement character);
if the short wave radio station receives the radio frequency signal containing the confirmation message, the radio frequency signal is converted into an audio signal and then is transmitted to a data transmission module;
the data transmission module receives and pre-processes the received audio signals, packages data obtained by the pre-processing after the receiving and sends the data to the main control module; the preprocessing after receiving comprises analog-to-digital conversion, signal demodulation and channel decoding;
if the confirmation result checked by the main control module is ACK, the short wave data transmission method is adopted to continuously transmit the next data message to the data transmission module; and if the confirmation result checked by the main control module is NACK, the short wave data sending party is adopted to repeatedly send a data message to the data transmission module.
As a preferable scheme, the method further comprises:
if the continuously received confirmation result of the main control module is that the times of NACK exceed a first preset value, sending a command for reducing the transmission rate to the data transmission module;
the data transmission module adjusts the data transmission rate according to the instruction and can also set the adjustment result to be fed back to the main control module. Further, the main control module modifies a waiting period corresponding to the waiting confirmation timer according to the feedback information of the data transmission module.
As a preferable scheme, the method further comprises:
if the number of times that the main control module does not receive the confirmation message in the waiting period of the waiting confirmation timer exceeds a second preset value, sending a transmission rate reduction instruction to the data transmission module;
the data transmission module adjusts the data transmission rate according to the instruction and can also set the adjustment result to be fed back to the main control module. Further, the main control module modifies a waiting period corresponding to the waiting confirmation timer according to the feedback information of the data transmission module.
As a preferred scheme, the calculation rule of the waiting period of the waiting confirmation timer is as follows:
T＝2L/S+T0，
wherein, T is waiting period, L is maximum length of message, S is transmission rate of data transmission module, T is0Is a fixed empirical time value.
As a preferred scheme, the master control module is also in communication connection with the short-wave radio station through a control interface;
if the main control module sends a command for reducing the transmission rate and receives feedback that the transmission rate of the data transmission module reaches the preset lowest rate, the main control module sends a frequency point setting command to the short wave radio station according to a preset frequency point switching table so as to complete corresponding frequency point switching.
As a preferable scheme, the method further comprises:
if the current transmission rate is not the preset highest rate and meets the preset recovery mechanism, the main control module sends an instruction for improving the transmission rate to the data transmission module;
and the data module adjusts the data transmission rate according to the instruction and feeds back the adjustment result to the main control module.
As a preferred scheme, the preset recovery mechanism includes but is not limited to: and the main control module continuously receives the confirmation result that the times of the ACK confirmation messages exceed a third preset value.
As a preferred scheme, the preset recovery mechanism further includes: when the current data transmission module is in an idle state, the transmission rate is firstly increased to a preset highest rate, then the test message is sent, if the ACK confirmation result sent by the opposite terminal can be received within the preset times, the current transmission rate is maintained, otherwise, the transmission rate is gradually reduced by adopting the method until the ACK confirmation result sent by the opposite terminal can be received within the preset times.
The invention also discloses a short wave data receiving method under the interference environment, which is based on the master control module, the data transmission module in communication connection with the master control module, and a short wave radio station connected with the data transmission module through an audio interface, and comprises the following steps:
the short wave radio station receives a radio frequency signal containing a data message or a confirmation message sent by an opposite terminal, converts the radio frequency signal into an audio signal and transmits the audio signal to the data transmission module;
the data transmission module receives and pre-processes the received audio signals, packages the audio signals obtained by the pre-processing after the receiving and sends the audio signals to the main control module; the preprocessing after receiving comprises analog-to-digital conversion, signal demodulation and channel decoding.
As a preferred scheme, the message includes a data message and a confirmation message;
if the main control module receives a data message sent by an opposite terminal, the received data message is verified, and a confirmation message containing an ACK (acknowledgement character) or NACK (negative acknowledgement character) confirmation result replied according to the verification result is sent to the data transmission module; the data transmission module unpacks the confirmation message and then carries out preprocessing before sending, and then sends the audio signal obtained through preprocessing before sending to the short-wave radio station; the preprocessing before sending comprises channel coding, narrow-band signal modulation and digital-to-analog conversion; the short wave radio station converts the audio signal containing the confirmation message into a radio frequency signal and then transmits the radio frequency signal to an opposite terminal;
if the main control module receives a confirmation message sent by the opposite terminal, selecting and sending a corresponding data message according to a confirmation result; the method specifically comprises the following steps: if the confirmation result checked by the main control module is ACK, continuously sending the next data message to the data transmission module; and if the confirmed result checked by the main control module is NACK, repeatedly sending the previous data message to the data transmission module. The data message sending method can adopt the short-wave data sending method for sending. The invention also discloses a short wave data transmission device in an interference environment, which comprises a main control module and a data transmission module which can simultaneously realize the short wave data transmission method and the short wave data receiving method. Wherein: the data transmission module is provided with:
a D/A converter for converting the modulated digital signal into an analog signal;
an A/D converter for converting an input analog signal into a digital signal;
the FPGA is used for channel coding and decoding and is used as a buffer area among the A/D converter, the D/A converter and the digital signal processing module;
a digital signal processor for modulating and demodulating a narrowband based audio signal;
and the microprocessor is used for communicating with the serial port of the main control module, unpacking the received data packet sent by the main control module, and packing the data sent by the FPGA and then sending the data to the main control module.
Correspondingly, the invention also discloses short-wave data transmission in an interference environment, which comprises a short-wave data transmission device with the characteristics and a short-wave radio station, wherein the short-wave radio station is connected and communicated with a data transmission module in the short-wave data transmission device through an audio interface; the short wave radio station is used for converting the audio signals sent by the data transmission module into radio frequency signals and then transmitting the radio frequency signals to the opposite terminal, and converting the received radio frequency signals transmitted by the opposite terminal into audio signals and then transmitting the audio signals to the data transmission module.
In the above scheme, the channel coding may include scrambling code, RS coding, hamming coding, interleaving, and frame synchronization; wherein: the scrambling codes are generated by a pseudo-random binary sequence generator and are used for scrambling transmission code streams, and long strings of '0' or '1' in the code streams are avoided; the RS code is (204, 188, t ═ 8), t is the number of errors that can be corrected, and the supervision segment is 16 check symbols; the Hamming code is (12,8,3), and each byte is added with 4-bit redundancy; the interweaving depth adopts a 4 x 4 matrix; the frame synchronization code adopts continuous 3 11-bit barker codes.
In the above scheme, the modulation mode of the audio signal is Frequency Shift Keying (FSK).
In the scheme, the channel bandwidth modulated by the audio signal is 300 Hz.
The invention has the following beneficial effects:
(1) the channel coding processing is carried out on the input data, so that the system has certain data error correction capability, the influence of channel error codes in the data transmission process can be effectively reduced, and the communication reliability is improved.
(2) The narrow-band audio signal is used for modulation, FSK is adopted as a modulation mode, and the channel bandwidth is reduced to 300Hz from the traditional 3kHz, so that the modulation mode has better transmission efficiency and anti-noise and anti-attenuation performances.
(3) And a confirmation mechanism is added in a link layer, and the transmission rate is adjusted according to a confirmation result, so that the reliability and stability of data transmission are improved.
(4) And a rate recovery mechanism is established to prevent the rate reduction caused by the burst interference, thereby ensuring the data receiving and transmitting efficiency.
(5) The invention is particularly suitable for special application scenes which are in a strong interference environment and have low requirements on transmission rate but require stable data transmission.
(6) The invention can provide certain anti-interference data transmission capability for the existing short-wave radio station without anti-interference communication capability, and can be used in cooperation with anti-interference means such as frequency hopping communication and high-power communication, thereby obtaining better anti-interference performance.
Drawings
FIG. 1 is a schematic diagram of the system components;
FIG. 2 is a hardware diagram of a data transmission module;
FIG. 3 is a flow chart of the data transfer module;
FIG. 4 is a schematic diagram of a data transmission process;
FIG. 5 is a schematic diagram of a data receiving process;
FIG. 6 is a schematic diagram of a data transmission confirmation process;
fig. 7 is a flow chart of a rate recovery mechanism.
Detailed Description
To explain the technical solution of the present invention more thoroughly, the short-wave data transmission device, system and method disclosed in the present invention are further explained with reference to specific embodiments and drawings.
As shown in fig. 1, the embodiment discloses a low-speed short-wave data transmission system mainly comprising a low-speed short-wave data transmission device and a short-wave radio station connected thereto, wherein the low-speed short-wave data transmission device mainly comprises a main control module and a data transmission module.
The main control module mainly realizes the functions of a link layer, and the main functions comprise: message transceiving, data checking, and link management (e.g., parameter configuration for transmission rate and frequency point switching). The main control module and the data transmission module are communicated by using a serial port to complete data receiving and transmitting and parameter configuration functions.
The data transmission module mainly realizes the functions of a physical layer, and the main functions comprise: in the data transmission process, channel coding of data information is completed, audio signal modulation based on a narrow-band channel is carried out on the coded data, and a modulated digital signal is converted into an analog signal (audio signal) and is transmitted to a short-wave radio station; in the data receiving process, the audio signal sampling, demodulation and channel decoding are completed, and the analyzed data information is sent to the main control module for processing.
The short-wave radio station works in a single-side band mode and is used for converting the low-frequency audio signal sent by the data transmission module into a radio frequency signal and finishing transmission in the data sending process; in the data receiving process, the received radio frequency signal is converted into an audio signal and then is sent to the data transmission module.
Referring to fig. 2, the data transmission module mainly comprises an a/D converter, a D/a converter, an FPGA, a DSP, and an MCU, and the connection relationship between the hardware units is as shown in fig. 2. The digital-to-analog converter is mainly used for converting a modulated digital signal into an analog signal (audio) and outputting the analog signal, and the A/D converter is mainly used for converting an input analog signal (audio) into a digital signal; the FPGA is mainly used for channel coding and decoding and is used as a buffer area among the A/D converter, the D/A converter and the DSP; the DSP is mainly used for modulating and demodulating audio signals; the MCU is mainly used for communicating with a serial port of the main control module.
In the process of sending the message, the MCU receives a data packet sent by the main control module through the serial port and carries out unpacking processing, the unpacked message information is sent to the FPGA for channel coding, then audio signal modulation is completed in the DSP, then the message information is sent to the FPGA for caching, and finally the modulated digital signal is converted into an analog signal (audio) through the D/A converter and then sent.
In the process of receiving the message, the audio signal received from the short wave radio station firstly enters an A/D converter for analog-to-digital conversion, then is sent to an FPGA for caching, then is sent to a DSP for audio signal demodulation, the demodulated data is returned to the FPGA for channel decoding, and finally is sent to a main control module through a serial port after being packaged by an MCU.
Referring to fig. 3, the data transmission module is mainly divided into four modules, i.e., a channel encoding module, an audio signal modulation module, an audio signal demodulation module, and a channel decoding module according to the processing flow.
The channel coding makes the system have certain data error correction capability and anti-interference capability by processing the input binary data information, reduces the influence of channel error codes in the data transmission process, and increases the reliability of data transmission. The channel coding in the system mainly comprises the steps of scrambling code, RS coding, Hamming coding, interleaving, frame synchronization and the like. The scrambling in the system is to scramble the transmission code stream by using the pseudo-random sequence generated by the pseudo-random binary sequence generator, so as to avoid long strings of '0' or '1' in the code stream. The RS in the present system is coded as (204, 188, t ═ 8), where t is the number of errors that can be corrected, the corresponding 188 symbols, and the supervision block is 16 check symbols (overhead part). The hamming code in this system is (12,8,3), i.e. each byte adds 4 bits of redundancy. The system adopts the interleaving depth of the 4 multiplied by 4 matrix, and comprehensively ensures the real-time performance and the transmission effectiveness of the message information. The system adopts a Barker code as a frame synchronization code, and in order to prevent the existence of the synchronization code in a data stream, the frame synchronization code adopts continuous 3 11-bit Barker codes. The channel decoding is the inverse process of the channel coding, i.e. the sequence of the channel decoding is opposite to the sequence of the channel coding, including frame synchronization extraction, de-interleaving, hamming decoding, RS decoding, and descrambling, and is not described herein again.
The data transmission module adopts a Frequency Shift Keying (FSK) audio signal modulation mode, the data modulation bandwidth is set to be 300Hz, and the FSK modulation has better anti-noise and anti-attenuation performances and is suitable for low-speed data transmission. Correspondingly, the audio signal demodulation is the FSK demodulation process. Certainly, besides FSK, ASK, PSK, etc. may be used as the modulation method of the data transmission module, but FSK is relatively more noise resistant than ASK and easier to implement than PSK.
The embodiment also discloses a low-speed short-wave data transmission method which mainly comprises three parts of sending, receiving and confirming.
As shown in fig. 4, the main steps of the sending end data sending process are as follows:
step 101, a main control module sends a message sending request to a data transmission module, and simultaneously starts a preset reply waiting timer, wherein the period of waiting for the reply of the data transmission module can be adjusted according to application requirements, for example, 3S;
102, the data transmission module judges whether the module is free to reply and allows transmission or not;
step 103, the main control module determines whether to send the message according to the reply; and when the data transmission module replies permission to send, the main control module sends a message. And when the data transmission module replies that the transmission is not allowed, the main control module continues to wait. If the main control module receives the message which is sent by the data transmission module and allowed to be sent in the period of waiting for reply, the message is sent; and the main control module does not receive the message allowing to be sent in the waiting period, and then sends the request sending instruction again when the waiting period is ended.
It should be noted that, if the main control module sends a data packet, a preset waiting acknowledgement timer is started after sending, and a receiving end waits for acknowledgement information (ACK or NACK) to be replied, and a period of waiting for acknowledgement information to be replied may be adjusted accordingly according to application requirements.
104, the data transmission module carries out channel coding on the message input from the serial port through the FPGA;
step 105, performing audio signal modulation on the frame data after channel coding through a DSP, converting the modulated digital signals into low-frequency audio signals through D/A, and inputting the low-frequency audio signals to a short-wave radio station;
and 106, converting the audio signal into a radio frequency signal by the short wave radio station, and finishing transmission.
As shown in fig. 5, the receiving end data receiving process mainly includes the following steps:
step 201, after receiving a signal sent by a sending end, a receiving end short wave radio station extracts an audio signal from a received radio frequency signal and transmits the audio signal to a data transmission module;
step 202, the data transmission module converts the received audio signal into a digital signal through A/D, and then completes audio signal demodulation in the DSP;
step 203, the data transmission module performs channel decoding on the demodulated data through the FPGA, and the decoded data is sent to the main control module through a serial port;
step 204, the main control module checks the received data message (for example, CRC check), checks whether the received message is correct, and then replies an ACK or NACK confirmation according to the check result, and the transmission of the confirmation information is the same as the transmission process in steps 101 to 106.
As shown in fig. 6, the main steps of the sender-side data acknowledgement procedure are as follows:
step 301, after the sending end receives the acknowledgement message fed back by the receiving end (the processing process of the receiving signal of the receiving end is the same as that in steps 201-204), if the main control module receives an ACK, the sending end continues to send the next message, and if the main control module receives an NACK, the last message is repeatedly sent, and meanwhile, the waiting acknowledgement timer is restarted;
step 302, if NACK is received three times (including that no ACK or NACK is received after timeout), the main control module sends a rate reduction instruction to the data transmission module, and modifies the corresponding transmission waiting acknowledgement time after the setting is successful, that is, resets the waiting acknowledgement timer;
and 303, if the transmission rate needs to be reduced and is already at the preset lowest rate, sending a frequency point setting instruction to the short-wave radio station according to a preset frequency point switching table to complete frequency point switching.
It should be noted that, in the embodiment, the transmission rate in the system is divided into three files, namely 15bps, 7.5bps and 3.75bps, but in a specific application, the division may be performed according to the application environment. The calculation rule of the waiting period (waiting confirmation time) of the waiting confirmation timer is as follows:
T＝2L/S+T0，
wherein, T is waiting period, L is maximum length of message, S is transmission rate of data transmission module, T is0A fixed time set according to experience of actual use.
It should be further noted that, the master control module may also only control the transmission rate when performing link management, and at this time, the master control module may not connect the short-wave radio station, and may adjust the sending frequency point of the short-wave radio station manually. However, as a preferred scheme of the present invention, in the embodiment, the master control module also remotely communicates with the short-wave radio station through a serial port, and when the frequency point switching is required, a frequency point switching instruction is sent to the short-wave radio station. For example, when the transmission rate reaches a preset minimum rate, the main control module sends a frequency point switching instruction for switching the frequency point from low to high to the short-wave radio station.
In order to prevent the rate reduction caused by the burst interference, a rate recovery mechanism is also established in the system, as shown in fig. 7. If the current transmission rate is not the highest rate, an attempt may be made to increase the transmission rate under certain conditions. For example: if the check result received by the main control module continuously for multiple times (for example, more than or equal to 100 times) is ACK in the sending process, the data transmission module may be instructed to increase the transmission rate and then continue sending. And after the transmission rate is increased, further paying attention to whether the data transmission is stable, specifically, the data transmission can be judged according to the continuously received check result, when the judgment is unstable, the original transmission rate is recovered, and the stability is maintained, which is not described in detail.
If the current system is idle, the transmission rate can be increased first and then the test message can be sent for a plurality of times, if the ACK can be received within the preset times, the current transmission rate is maintained, otherwise, the transmission rate is restored to the transmission rate before the transmission rate is increased in advance.
Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments and application fields, and the above-described embodiments are illustrative, instructive, and not restrictive. Those skilled in the art, having the benefit of this disclosure, may effect numerous modifications thereto without departing from the scope of the invention as defined by the appended claims.
Claims (8)
1. The short wave data transmission method under the interference environment is characterized in that the short wave data transmission method is based on a master control module, a data transmission module in communication connection with the master control module, and a short wave radio station connected with the data transmission module through an audio interface, and comprises the following steps:
the main control module sends a message sending request and starts a preset reply waiting timer;
the data transmission module replies whether to allow transmission according to the state of the data transmission module, when the data transmission module is in an idle state, the data transmission module replies to allow transmission, otherwise, the data transmission module replies to disallow transmission;
if the main control module does not receive a reply decision which is transmitted back by the data transmission module and allowed to be transmitted, the main control module transmits a message transmission request to the data transmission module again; if a reply decision which is transmitted back by the data transmission module and allows transmission is received in the waiting period, transmitting the message content to the data transmission module;
the data transmission module unpacks the message content sent by the main control module and then carries out preprocessing before sending, and then sends the audio signal obtained by preprocessing before sending to the short wave radio station; the preprocessing before sending comprises channel coding, narrow-band signal modulation and digital-to-analog conversion;
the short wave radio station converts the input audio signal into a radio frequency signal and then transmits the radio frequency signal to the opposite terminal;
the message includes a data message and a confirmation message, and if the message content to be sent by the message sending request is the data message, the method further includes:
after the main control module sends the data message, a preset waiting confirmation timer is started, and a confirmation message containing a data message confirmation result sent by an opposite terminal is waited, wherein the confirmation result comprises ACK (acknowledgement character) or NACK (negative acknowledgement character);
if the short wave radio station receives the radio frequency signal containing the confirmation message, the radio frequency signal is converted into an audio signal and then is transmitted to a data transmission module;
the data transmission module receives and pre-processes the received audio signals, packages data obtained by the pre-processing after the receiving and sends the data to the main control module; the preprocessing after receiving comprises analog-to-digital conversion, signal demodulation and channel decoding;
if the confirmed result checked by the main control module is ACK, continuing to send a message sending request to the data transmission module to send the next data message; and if the checked confirmation result is NACK, continuing to send a message sending request to repeatedly send the previous data message to the data transmission module.
2. The short wave data transmission method of claim 1, further comprising:
if the number of times of NACK (negative acknowledgement) continuously received by the main control module exceeds a first preset value or the number of times of not receiving the acknowledgement message by the main control module in the waiting period of the waiting acknowledgement timer exceeds a second preset value, sending an instruction for reducing the transmission rate to the data transmission module;
the data transmission module adjusts the data transmission rate according to the instruction;
and the main control module modifies a waiting period corresponding to the waiting confirmation timer according to the adjusted transmission rate.
3. The short-wave data transmission method of claim 2, wherein the master control module is further communicatively connected to the short-wave radio station through a control interface;
and if the transmission rate reaches the preset minimum rate, the main control module sends a frequency point setting instruction to the short-wave radio station according to the preset frequency point switching table so as to complete corresponding frequency point switching.
4. The ultra-low speed short wave data transmission method of claim 1, further comprising:
if the current transmission rate is not the preset highest rate and meets the preset recovery mechanism, the main control module sends an instruction for improving the transmission rate to the data transmission module;
the data transmission module adjusts the data transmission rate according to the instruction and feeds back the adjustment result to the main control module;
the preset recovery mechanism includes but is not limited to: and the main control module continuously receives the confirmation result that the times of the ACK confirmation messages exceed a third preset value.
5. The utility model provides a short wave data receiving method under interference environment which characterized in that, based on master control module and rather than the data transmission module of communication connection to and the short wave radio station of being connected through audio interface and data transmission module, include:
the short wave radio station receives a radio frequency signal containing a message sent by an opposite terminal, converts the radio frequency signal into an audio signal and transmits the audio signal to the data transmission module;
the data transmission module receives and pre-processes the received audio signals, packages data obtained by the pre-processing after the receiving and sends the data to the main control module; the preprocessing after receiving comprises analog-to-digital conversion, signal demodulation and channel decoding;
the message comprises a data message and a confirmation message; the method further comprises the following steps:
if the main control module receives a data message sent by an opposite terminal, the received data message is verified, and a confirmation message containing an ACK (acknowledgement character) or NACK (negative acknowledgement character) confirmation result is sent to the data transmission module according to the verification result;
the data transmission module unpacks the confirmation message and then carries out preprocessing before sending, and then sends the audio signal obtained through preprocessing before sending to the short-wave radio station; the preprocessing before sending comprises channel coding, narrow-band signal modulation and digital-to-analog conversion;
the short wave radio station converts the audio signal containing the confirmation message into a radio frequency signal and then transmits the radio frequency signal to an opposite terminal;
if the main control module receives a confirmation message sent by the opposite terminal, selecting and sending a corresponding data message according to a confirmation result; the method specifically comprises the following steps: if the confirmation result checked by the main control module is ACK, continuously sending the next data message to the data transmission module; and if the confirmed result checked by the main control module is NACK, repeatedly sending the previous data message to the data transmission module.
6. Short-wave data transmission device in an interference environment, comprising a master control module and a data transmission module, which are capable of implementing the short-wave data transmission method according to claims 1 to 4 and the short-wave data reception method according to claim 5, wherein:
the data transmission module is provided with:
a D/A converter for converting the modulated digital signal into an analog signal;
an A/D converter for converting an input analog signal into a digital signal;
the FPGA is used for channel coding and decoding and is used as a buffer area among the A/D converter, the D/A converter and the digital signal processing module;
a digital signal processor for modulating and demodulating a narrowband based audio signal;
and the microprocessor is used for communicating with the serial port of the main control module, unpacking the received data packet sent by the main control module, and packing the data sent by the FPGA and then sending the data to the main control module.
7. The short wave data transmission arrangement of claim 6, wherein the channel coding comprises scrambling code, RS coding, Hamming coding, interleaving, frame synchronization; wherein:
the scrambling codes are transmitted code streams scrambled by a pseudo-random sequence generated by a pseudo-random binary sequence generator; the RS code is (204, 188, t ═ 8), t is the number of errors that can be corrected, and the supervision segment is 16 check symbols;
the Hamming code is (12,8,3), and each byte is added with 4-bit redundancy;
the interweaving depth adopts a 4 x 4 matrix;
the frame synchronization code adopts continuous 3 11-bit barker codes.
8. The short wave data transmission device of claim 7 wherein the modulation of the audio signal is frequency shift keying.
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Effective date of registration: 20240314 Address after: 210046 Within Nanjing Economic and Technological Development Zone, Jiangsu Province (No. 301 Zhongshan East Road, Xuanwu District) Patentee after: PANDA ELECTRONICS GROUP Co.,Ltd. Country or region after: China Address before: 210002 No. 301 East Zhongshan Road, Jiangsu, Nanjing Patentee before: PANDA ELECTRONICS GROUP Co.,Ltd. Country or region before: China Patentee before: NANJING PANDA HANDA TECHNOLOGY Co.,Ltd. |