CN108989251A - A kind of communication system based on shortwave narrowband waveform - Google Patents
A kind of communication system based on shortwave narrowband waveform Download PDFInfo
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- CN108989251A CN108989251A CN201810800734.6A CN201810800734A CN108989251A CN 108989251 A CN108989251 A CN 108989251A CN 201810800734 A CN201810800734 A CN 201810800734A CN 108989251 A CN108989251 A CN 108989251A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0014—Carrier regulation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/18—Phase-modulated carrier systems, i.e. using phase-shift keying
- H04L27/20—Modulator circuits; Transmitter circuits
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2657—Carrier synchronisation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0014—Carrier regulation
- H04L2027/0024—Carrier regulation at the receiver end
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Power Engineering (AREA)
- Noise Elimination (AREA)
Abstract
The invention belongs to New Technology Of Shortwave Communication fields, disclose a kind of communication system based on shortwave narrowband waveform, using the short wave communication Design of Signal method of more narrow bandwidth, by reducing signal transmission bandwidth, reducing out-of-band noise influences, and improves unit hertz power spectral density, improves short wave communication data transmission performance；It may be directly applied to existing short wave communication equipment, have many advantages, such as strong antijamming capability, reliable and stable, adaptable, can further promote existing short wave communication equipment performance.
Description
Technical field
The invention belongs to New Technology Of Shortwave Communication field more particularly to a kind of communication systems based on shortwave narrowband waveform.
Background technique
Short wave communication relies primarily on ionosphere transmitting and is communicated, and Dispersive Channels when ionospheric channel is a kind of are special
Point is that path loss, time delay spread, noise and interference etc. all constantly change with frequency, place, season, variation round the clock.Therefore,
Communication noise and space interference are the inevitable major issues of receiver, design the characteristics of research staff is according to short wave communication,
It has been devoted to the research of data transmission credibility, but since short-wave signal is affected by factors such as weather, landform, from
It is difficult have preferable method to solve the problems, such as this in terms of noise robustness.Transmission performance can not further increase, and technical level reaches
Bottleneck.
Narrow band waveform and the performance difference of other waveforms are little in short range, and under remote sky wave environment,
Since narrow band waveform narrower bandwidth falls into the useless letter in waveform bandwidth under the environmental factors such as identical interference and noise
Number less, such receiver is smaller by being influenced.In addition, designer can reduce useful signal to the greatest extent by technological means
Superposition loss, so, narrow band waveform has obviously advantage under sky wave environment.
Existing short-wave transmitter, receiver are generally communicated using the waveform of 3KHz bandwidth, and the waveform is in short distance
It is effected by environmental factors smaller in communication, existing modulation-demodulation technique can satisfy index request.Existing shortwave wave
In actual use, by frequency, latitude, weather, environmental factors are affected shape technology round the clock etc., and signal is caused to pass
Transmission quality is not high, or even influences normally receiving for signal, and range can be led to by reducing shortwave, especially after distance zooms out, in morning 1
O'clock between 3 points, the insecure problem of data transmission performance starts to highlight, and the development for seriously constraining short wave communication distance is wanted
It asks.
Summary of the invention
In view of the above-mentioned problems, the purpose of the present invention is to provide a kind of communication system based on shortwave narrowband waveform, it can
The reliability for guaranteeing Short Wave Data Transmission, expands the radius of short wave communication.
In order to achieve the above objectives, the present invention is realised by adopting the following technical scheme.
A kind of communication system based on shortwave narrowband waveform, the communication system include at least: transmitter and receiver,
It is provided with sequentially connected transmission data processing unit in the transmitter, sends formed filter and Channel Elements；Its
In, in the range of the filtering bandwidth for sending formed filter is 1kHz to 1.5kHz；
It is provided with sequentially connected Channel Elements in the receiver, receive low-pass filter, bandpass filter and receives data
Processing unit；Wherein, in the range of the filtering bandwidth of the low-pass filter is 1kHz to 1.5kHz, the bandpass filter
Filtering bandwidth be 1kHz to 1.5kHz in the range of.
The characteristics of technical solution of the present invention and further improvement are as follows:
(1) in the transmitter:
The transmission data processing unit for data to be sent to be divided into multiple data frames, and completes the volume of data to be sent
Code interweaves, the modulation of walsh spread spectrum, scrambling code and baseband waveform；
The transmission formed filter, for completing Waveform shaping, and the filtering bandwidth for limiting waveform to be sent is arrived as 1kHz
In the range of 1.5kHz；
The Channel Elements, for completing the frequency up-conversion operation of carrier frequency, make the carrier frequency 2MHz~30MHz it
Between, and sent the carrier frequency by radio-frequency module, form sky wave waveform.
(2) in the receiver:
The Channel Elements are AD converted for capturing sky wave waveform, the down-conversion operation of carrier frequency are completed, high frequency
Information is transformed into the manageable base-band information of DSP unit；
The reception low-pass filter, for carrying out bandwidth inhibition to reception waveform；
The bandpass filter, for filtering out the Wave data outside 1kHz to 1.5kHz bandwidth；
The reception data processing unit determines sync bit for completing data synchronous, channel estimation and channel equalization, complete
At scrambling code, solution walsh, deinterleaving operation is gone, decoded operation is finally completed, useful data is obtained.
(3) filtering bandwidth for sending formed filter is 1.24kHz, and the filtering bandwidth of the low-pass filter is
1.24kHz, the filtering bandwidth of the bandpass filter are 1.24kHz.
(4) the transmission data processing unit, for data to be sent to be divided into multiple data frames, wherein each
The frame structure of data frame successively includes: a synchronization header sequence, a start of message (SOM) sequence, multiple alternately repeated segments
According to the message ends sequence after sequence and corresponding synchronization header sequence and the last one segment data sequence；
Wherein, each synchronization header sequence includes 80 sign bits, and the start of message (SOM) sequence includes 32 bits, described
Segment data sequence includes 176 sign bits, and the message ends sequence includes 32 bits.
(5) the segment data sequence includes four unknown data sequences and three given data sequences, and each unknown
Data sequence and each given data sequence are alternately repeated, wherein each unknown data sequence includes 32 sign bits, Mei Geyi
Primary data sequence includes 16 sign bits.
(6) the synchronization header sequence, for carrying bit synchronization information and carrier synchronization information；
The start of message (SOM) sequence starts to transmit segment data sequence for indicating；
The segment data sequence, is used for transmission data information；
The message ends sequence, for indicating all segment data sequence ends of transmission.
Technical solution of the present invention is the short wave communication application problem solved under special occasions, is proposed a kind of using narrower band
Wide short wave communication Design of Signal method, by reducing signal transmission bandwidth, reducing out-of-band noise influences, and improves unit hertz function
Rate spectrum density improves short wave communication data transmission performance；It may be directly applied to existing short wave communication equipment, there is anti-interference ability
By force, the advantages that reliable and stable, adaptable, can further promote existing short wave communication equipment performance.
Detailed description of the invention
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
Some embodiments of invention for those of ordinary skill in the art without creative efforts, can be with
It obtains other drawings based on these drawings.
Fig. 1 is a kind of shortwave narrowband waveform frame structural schematic diagram provided in an embodiment of the present invention；
Fig. 2 is that subcarrier provided in an embodiment of the present invention modulates schematic diagram；
Fig. 3 is the time domain waveform and frequency-domain waveform schematic diagram provided in an embodiment of the present invention for sending formed filter；
Fig. 4 is the time domain waveform and frequency-domain waveform schematic diagram provided in an embodiment of the present invention for receiving low-pass filter；
Fig. 5 is the time domain waveform and frequency-domain waveform schematic diagram of bandpass filter provided in an embodiment of the present invention.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other
Embodiment shall fall within the protection scope of the present invention.
The embodiment of the present invention provides a kind of communication system based on shortwave narrowband waveform, and the communication system includes at least:
Transmitter and receiver.
It is provided with sequentially connected transmission data processing unit in the transmitter, sends formed filter and channel list
Member；Wherein, in the range of the filtering bandwidth for sending formed filter is 1kHz to 1.5kHz；
It is provided with sequentially connected Channel Elements in the receiver, receive low-pass filter, bandpass filter and receives data
Processing unit；Wherein, in the range of the filtering bandwidth of the low-pass filter is 1kHz to 1.5kHz, the bandpass filter
Filtering bandwidth be 1kHz to 1.5kHz in the range of.
You need to add is that in the transmitter:
The transmission data processing unit for data to be sent to be divided into multiple data frames, and completes the volume of data to be sent
Code interweaves, the modulation of walsh spread spectrum, scrambling code and baseband waveform；
The transmission formed filter, for completing Waveform shaping, and the filtering bandwidth for limiting waveform to be sent is arrived as 1kHz
In the range of 1.5kHz；
The Channel Elements, for completing the frequency up-conversion operation of carrier frequency, make the carrier frequency 2MHz~30MHz it
Between, and sent the carrier frequency by radio-frequency module, form sky wave waveform.
Also you need to add is that, in the receiver:
The Channel Elements are AD converted for capturing sky wave waveform, the down-conversion operation of carrier frequency are completed, high frequency
Information is transformed into the manageable base-band information of DSP unit；
The reception low-pass filter, for reducing and being brought in air traffic channel transmission process to waveform progress bandwidth inhibition is received
Influence of noise；
The bandpass filter reduces out-of-band interference bring shadow for filtering out the Wave data outside 1kHz to 1.5kHz bandwidth
It rings, as the supplement for receiving low-pass filter, further improves the interference free performance of the transmitted waveform；
The reception data processing unit determines sync bit for completing data synchronous, channel estimation and channel equalization, complete
At scrambling code, solution walsh, deinterleaving operation is gone, decoded operation is finally completed, useful data is obtained.
Preferably, the filtering bandwidth for sending formed filter is 1.24kHz, the filtering bandwidth of the low-pass filter
For 1.24kHz, the filtering bandwidth of the bandpass filter is 1.24kHz.
Further, the transmission data processing unit, for data to be sent to be divided into multiple data frames, wherein every
The frame structure of a data frame successively includes: a synchronization header sequence, a start of message (SOM) sequence, multiple alternately repeated segmentations
The message ends sequence after data sequence and corresponding synchronization header sequence and the last one segment data sequence；
Wherein, each synchronization header sequence includes 80 sign bits, and the start of message (SOM) sequence includes 32 bits, described
Segment data sequence includes 176 sign bits, and the message ends sequence includes 32 bits.
Further, the segment data sequence includes four unknown data sequences and three given data sequences, and every
A unknown data sequence and each given data sequence are alternately repeated, wherein and each unknown data sequence includes 32 sign bits,
Each given data sequence includes 16 sign bits.
Specifically,
The synchronization header sequence, for carrying bit synchronization information and carrier synchronization information；
The start of message (SOM) sequence starts to transmit segment data sequence for indicating；
The segment data sequence, is used for transmission data information；
The message ends sequence, for indicating all segment data sequence ends of transmission.
Illustratively, the narrow band waveform that the present invention designs mainly is realized in the DSP unit of short-wave transmitter and receiver.
Waveform Design, waveform modulated, filter design are completed on the platform and receive data processing.
(1) Waveform Design
Narrow band waveform is used for transfer data information, including detection information and link information, and waveform frame structure is by following four differences
Function transmits stage composition, as shown in Figure 1.
The synchronization header stage: modulator sends synchronization header sequence, and the demodulator of receiving end is enable to obtain bit synchronization and load
Wave is synchronous.
Stage start of message (SOM): after synchronization header is sent completely, a fixed bit sequence, data hair are sent to encoder
The all stage the sent sequence is only sent once.
Data phase: unknown data output phase after code interleaving answers bit information, and it is (same to carry out walsh to the information
Walk orthogonal) spread spectrum, scrambling code operation is then completed, final channel symbol, i.e. Data sequence in Fig. 1, in Data sequence are formed
In intert given data (i.e. Trn sequence in Fig. 1) form a data block, the data phase by several data chunks at.
The message ends stage: after data are sent completely, sending a fixed bit sequence to encoder, what data were sent
The all stage sequence is only sent once.
(2) waveform modulated
Channel symbol value is mapped to carrier phase and the modulated process of subsequence carrier wave is as follows:
The modulated wave signal that signal forms 1800Hz using phase-shift keying (PSK) modulation system is sent, transmission rate is 1200 channels
Symbol/second.The signal is divided into real and imaginary parts, this two paths of signals passes through interpolation and equivalent low-pass filter filtering respectively, with
Specific bandwidth is provided and mirror image inhibits.By interpolation and the real and imaginary parts signal of filtering for modulating 1800Hz subcarrier,
As shown in Figure 2.Wherein modem must be able to the frequency of tolerance transmitting terminal and the +/- 37.5Hz of receiving end high frequent carrier frequency
The frequency-tracking speed of offset and most 3.5Hz/s.LPF indicates low-pass filter in Fig. 2.
(3) filter designs
The present invention using window function metht design digital filter, have many advantages, such as design simply, conveniently, it is practical.By MATLAB
Language starts filter constructing graphic interface, and structural belt has the FIR filter of window function, generates and rings about the frequency of filter
It answers.
It sends formed filter and receives low-pass filter and use raised cosine and square root raised cosine filter respectively, wherein
Rolloff-factor value is 0.16, bandwidth 1240Hz, 1200 symbols of rate/second.It is illustrated in figure 3 the time domain wave for sending formed filter
Shape and frequency-domain waveform are illustrated in figure 4 the time domain waveform and frequency-domain waveform for receiving low-pass filter.
Simultaneously as software is the data for transmitting 1.24KHz under 3KHz bandwidth condition, in order to reduce the shadow of out-of-band interference
It rings, therefore needs to be illustrated in figure 5 the time domain waveform and frequency of bandpass filter first to data progress bandpass filtering is received in receiving end
Domain waveform.
(4) data processing is received
Data are synchronous: radio-frequency front-end receives data and passes through down coversion, send to DSP processing unit, goes by receiving low-pass filter
It is related that displacement is done to local sequence after carrier wave, then carries out DFT and modulo operation, finds out peak-peak and peak-peak is sat
Then mark calculates frequency deviation and signal-to-noise ratio, determines sync bit according to pre-set thresholding.
Channel estimation: μ channel estimation method can be changed using LMS (lowest mean square), Normalized LMS Algorithm is to convergence factor μ
It is normalized, to ensure the convergence stability of adaptive equalization algorithm.As long as guaranteeing the condition of convergence: 0 < μ < 1, it is ensured that
By sufficiently large n times iteration, algorithm being capable of stable convergence.Improved variable step decorrelation LMS algorithm utilizes input signal
Quadrature component updates the parameter of adaptive equalizer, can accelerate the convergence rate of LMS algorithm.
Channel equalization: using NDDE, that is, non-linear piece formula Data Detection, recursively uses Levinson (Paul levinson) algorithm
Carry out solution matrix equation.Only two symbols of first and last are made decisions first, and using its result as additional training symbol, from
Effect caused by the two symbols is subtracted in equation, obtains the matrix equation of new reduction dimension, then with Levinson (Lai Wen
It is gloomy) algorithm solution.And so on, until obtaining whole judgement symbols.In this way, due to reducing intersymbol in every step valuation
Uniform MSE (mean square error) distribution then just can be obtained in the quantity of crosstalk.If feedback symbol judgement be correctly,
NDDE technology ensure the performance in every step valuation will not descend by.
Technical solution of the present invention uses advanced narrow band communication waveform, efficiently solves active service aviation shortwave transceiver and there is frequency
The problems such as road is crowded, poor anti jamming capability improves the reliability of data transmission, compensates for broadband connections in practical applications
It is insufficient.
Those of ordinary skill in the art will appreciate that: realize that all or part of the steps of above method embodiment can pass through
The relevant hardware of program instruction is completed, and program above-mentioned can store in computer-readable storage medium, which exists
When execution, step including the steps of the foregoing method embodiments is executed；And storage medium above-mentioned includes: ROM, RAM, magnetic or disk
Etc. the various media that can store program code.
The above description is merely a specific embodiment, but scope of protection of the present invention is not limited thereto, any
Those familiar with the art in the technical scope disclosed by the present invention, can easily think of the change or the replacement, and should all contain
Lid is within protection scope of the present invention.Therefore, protection scope of the present invention should be based on the protection scope of the described claims.
Claims (7)
1. a kind of communication system based on shortwave narrowband waveform, the communication system include at least: transmitter and receiver, it is special
Sign is,
It is provided with sequentially connected transmission data processing unit in the transmitter, sends formed filter and Channel Elements；Its
In, in the range of the filtering bandwidth for sending formed filter is 1kHz to 1.5kHz；
It is provided with sequentially connected Channel Elements in the receiver, receive low-pass filter, bandpass filter and receives data
Processing unit；Wherein, in the range of the filtering bandwidth of the low-pass filter is 1kHz to 1.5kHz, the bandpass filter
In the range of filtering bandwidth is 1kHz to 1.5kHz.
2. a kind of communication system based on shortwave narrowband waveform according to claim 1, which is characterized in that in the transmitting
In machine:
The transmission data processing unit for data to be sent to be divided into multiple data frames, and completes the volume of data to be sent
Code interweaves, the modulation of walsh spread spectrum, scrambling code and baseband waveform；
The transmission formed filter, for completing Waveform shaping, and the filtering bandwidth for limiting waveform to be sent is arrived as 1kHz
In the range of 1.5kHz；
The Channel Elements, for completing the frequency up-conversion operation of carrier frequency, make the carrier frequency 2MHz~30MHz it
Between, and sent the carrier frequency by radio-frequency module, form sky wave waveform.
3. a kind of communication system based on shortwave narrowband waveform according to claim 1, which is characterized in that in the reception
In machine:
The Channel Elements are AD converted for capturing sky wave waveform, the down-conversion operation of carrier frequency are completed, high frequency
Information is transformed into the manageable base-band information of DSP unit；
The reception low-pass filter, for carrying out bandwidth inhibition to reception waveform；
The bandpass filter, for filtering out the Wave data outside 1kHz to 1.5kHz bandwidth；
The reception data processing unit determines sync bit for completing data synchronous, channel estimation and channel equalization, complete
At scrambling code, solution walsh, deinterleaving operation is gone, decoded operation is finally completed, useful data is obtained.
4. a kind of communication system based on shortwave narrowband waveform according to claim 1, which is characterized in that it is described send at
The filtering bandwidth of mode filter is 1.24kHz, and the filtering bandwidth of the low-pass filter is 1.24kHz, the bandpass filter
Filtering bandwidth be 1.24kHz.
5. a kind of communication system based on shortwave narrowband waveform according to claim 2, which is characterized in that the transmission number
According to processing unit, for data to be sent to be divided into multiple data frames, wherein the frame structure of each data frame successively includes: one
A synchronization header sequence, a start of message (SOM) sequence, multiple alternately repeated segment data sequences and corresponding synchronization header sequence
The message ends sequence after column and the last one segment data sequence；
Wherein, each synchronization header sequence include 80 sign bits, the start of message (SOM) sequence include 32 bits, described point
Segment data sequence includes 176 sign bits, and the message ends sequence includes 32 bits.
6. a kind of communication system based on shortwave narrowband waveform according to claim 5, which is characterized in that
The segment data sequence includes four unknown data sequences and three given data sequences, and each unknown data sequence
It is alternately repeated with each given data sequence, wherein each unknown data sequence includes 32 sign bits, each given data sequence
Column include 16 sign bits.
7. a kind of communication system based on shortwave narrowband waveform according to claim 5, which is characterized in that
The synchronization header sequence, for carrying bit synchronization information and carrier synchronization information；
The start of message (SOM) sequence starts to transmit segment data sequence for indicating；
The segment data sequence, is used for transmission data information；
The message ends sequence, for indicating all segment data sequence ends of transmission.
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| CN201810800734.6A CN108989251A (en) | 2018-07-20 | 2018-07-20 | A kind of communication system based on shortwave narrowband waveform |
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| CN201810800734.6A CN108989251A (en) | 2018-07-20 | 2018-07-20 | A kind of communication system based on shortwave narrowband waveform |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113242065A (en) * | 2021-05-20 | 2021-08-10 | 东南大学 | Sky wave large-scale MIMO uplink synchronization method using position information |
| CN113923084A (en) * | 2021-10-09 | 2022-01-11 | 中国电波传播研究所（中国电子科技集团公司第二十二研究所） | Anti-noise high-time-resolution broadband short wave channel measuring method |
-
2018
- 2018-07-20 CN CN201810800734.6A patent/CN108989251A/en not_active Withdrawn
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113242065A (en) * | 2021-05-20 | 2021-08-10 | 东南大学 | Sky wave large-scale MIMO uplink synchronization method using position information |
| CN113923084A (en) * | 2021-10-09 | 2022-01-11 | 中国电波传播研究所（中国电子科技集团公司第二十二研究所） | Anti-noise high-time-resolution broadband short wave channel measuring method |
| CN113923084B (en) * | 2021-10-09 | 2023-04-28 | 中国电波传播研究所（中国电子科技集团公司第二十二研究所） | Anti-noise high-time-resolution broadband short wave channel measurement method |
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Application publication date: 20181211 |