CN109495174A - A kind of airborne laser communication method based on OFDM modulation /demodulation - Google Patents
A kind of airborne laser communication method based on OFDM modulation /demodulation Download PDFInfo
- Publication number
- CN109495174A CN109495174A CN201811618434.2A CN201811618434A CN109495174A CN 109495174 A CN109495174 A CN 109495174A CN 201811618434 A CN201811618434 A CN 201811618434A CN 109495174 A CN109495174 A CN 109495174A
- Authority
- CN
- China
- Prior art keywords
- receiving end
- demodulation
- channel
- transmitting terminal
- laser communication
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
-
- 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
- H04L27/2602—Signal structure
- H04L27/2605—Symbol extensions, e.g. Zero Tail, Unique Word [UW]
- H04L27/2607—Cyclic extensions
-
- 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
- H04L27/2626—Arrangements specific to the transmitter only
- H04L27/2627—Modulators
- H04L27/2628—Inverse Fourier transform modulators, e.g. inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators
-
- 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
- H04L27/2649—Demodulators
- H04L27/265—Fourier transform demodulators, e.g. fast Fourier transform [FFT] or discrete Fourier transform [DFT] demodulators
-
- 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
- H04L27/2689—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation
- H04L27/2695—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation with channel estimation, e.g. determination of delay spread, derivative or peak tracking
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Discrete Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Mathematical Physics (AREA)
- Electromagnetism (AREA)
- Optical Communication System (AREA)
Abstract
The present invention is a kind of airborne laser communication method based on OFDM modulation /demodulation, and air craft carried equipment and ground installation are respectively equipped with a transmitting terminal and a receiving end.Serial data stream is become the road N parallel subcarriers by the transmitting terminal of local terminal, corrected coding, constellation mapping are added training data sequence, add cyclic prefix again after IFFT transformation, modulation generates analog signal code stream driving laser and is emitted, and is transmitted to opposite end through atmospheric channel.The receiving end detection of opposite end receives optical signal and is converted to analog signal code stream, and channel estimation and signal compensation are carried out after analog-to-digital conversion, removes cyclic prefix, and FFT and constellation demapping restore multidiameter delay subcarrier, then corrected decoding, parallel-serial conversion restoring data.This method obtains performance gain using the variation of channel estimation tracking atmospheric channel shock response and frequency response；It is effective against under motor-driven aircraft height, strong vibration and atmospheric channel bumpy weather and is effective against accidental channel decline, promote communication quality.
Description
Technical field
The present invention relates to wireless light communication technical field, specially a kind of airborne laser communication based on OFDM modulation /demodulation
Method.
Background technique
Wireless light communication relative to conventional wireless microwave communication mode major advantage is message capacity big, good concealment, anti-
Interference performance is strong, terminal volume is small, light-weight, low in energy consumption, can sufficiently meet it is air craft carried under the conditions of large capacity business transmit
Demand.But high maneuverability, strong vibration environment and the atmospheric channel disturbance of aircraft carrier (especially unmanned plane) greatly restrict
Air craft carried laser communication application prospect.
Due to atmospheric perturbation in atmospheric channel, it will lead to radio optical communication system and receive the generation arrival of end detector glazing spot
Angle rises and falls and drift, causes the intersymbol interference (ISI) of system signal multipath transmisstion, destroys the orthogonality of intercarrier, generates atmosphere
Accidental channel decline under disturbance.
Under the conditions of the aircraft motion of automobile path length difference of multiple transmission paths be influence wireless light communication performance it is main because
One of element, existing airborne laser communication are difficult to the influence for effectively overcoming path difference to system performance, can not be adapted to aircraft machine
The maneuverability requirement of dynamic characteristic, especially unmanned plane also can not be corrected and restore to received data, and performance gain is difficult to
It is promoted.
OFDM (Orthogonal Frequency Division Multiplexing, orthogonal frequency division multiplexing) is that one kind is more
Carrier transmission technique is used widely in the Wireless microwave communications field, can effectively improve communication system transmission rate,
Peak power ratio (PAPR), anti-multipath jamming ability can be obtained in the case where equivalent channel environment, transmission range and more effectively be supported
Anti- accidental channel fading capability.Exactly air craft carried laser communication environment resistant vibration and the atmospheric perturbation at present of these good characteristics
It is required.But OFDM technology is not yet applied to air craft carried wireless light communication.
Summary of the invention
It is air craft carried to swash the purpose of the present invention is designing a kind of airborne laser communication method based on OFDM modulation /demodulation
Optical communication equipment and corresponding earthbound laser communication equipment are respectively equipped with a transmitting terminal and a receiving end.The transmitting terminal of local terminal will
Customer service electric signal is adapted to serial data stream, then serioparallel exchange generates the road N parallel subcarriers (also known as sub-data flow), respectively
Error Correction of Coding, constellation mapping are carried out, then carries out fast discrete Fourier inversion, training data sequence is added later, then plus follow
Ring prefix CP generates analog signal code stream driving laser by digital-to-analogue conversion, low-pass filtering and is emitted, passed through atmospheric channel
It is sent to opposite end.The receiving end of opposite end is converted to electric signal to signal optical detection reception, low-pass filtered, obtain analog signal code stream
Be input to DSP through analog-to-digital conversion and carry out channel estimation and signal compensation, remove cyclic prefix CP, fast discrete Fourier transformation and
Constellation demapping restores to obtain the road N parallel subcarriers, and after carrying out error correction decoding respectively, parallel-serial conversion is serial data stream, adaptation
It is exported at the matched electric signal of business.This method promotes wireless light communication aircraft height is motor-driven, strong vibration environment and big
The anti-accidental channel fading capability of airborne laser communication system under the conditions of gas channel perturbation, and then lifting system communication quality, change
Kind communication performance.Airborne laser communication system of the invention completely eliminates destruction of the multipath transmisstion to intercarrier orthogonality, can have
Effect resists accidental channel decline, and can effectively overcome influence of the path difference to system performance, can more be adapted to the flight such as unmanned plane
The requirement of device high maneuverability.
One kind that the present invention designs is based on OFDM, and (Orthogonal Frequency DivisionMultiplexing is i.e.
Orthogonal frequency division multiplexi) modulation /demodulation airborne laser communication method is using air craft carried laser communication gear and it is corresponding
The mutual receiving and transmitting signal of earthbound laser communication equipment, air craft carried laser communication gear and corresponding earthbound laser communication equipment
It is respectively equipped with a transmitting terminal and a receiving end, be respectively used to transmitting local terminal optical signal and receives opposite end optical signal.
The electric signal of customer service input interface is adapted to serial data stream first by the transmitting terminal of local terminal, then is passed through
Serial data stream is become the road N parallel subcarriers by serioparallel exchange, and N is the quantity of ofdm system sub-carriers, and the parallel son in the road N is carried
Every subcarriers of wave carry out Error Correction of Coding, constellation mapping respectively, and the subcarrier after mapping carries out fast discrete Fourier contravariant
IFFT is changed, training data sequence is added before the ifft or later, which is that transmitting terminal and receiving end are known
The data sequence of value and position；Finally add cyclic prefix CP again, becomes analog signal code stream by digital-to-analogue conversion, then through low pass
It drives laser to carry out multi-carrier light transmitting after filtering, is transmitted to opposite end through atmospheric channel.
The receiving end of opposite end passes through photodetection first and signal light is detected and received, and received signal light turns
It is changed to electric signal and carries out low-pass filtering treatment, obtain analog signal code stream, then carry out analog to digital conversion to become digital signal code stream, it
Channel estimation and signal compensation are carried out afterwards, removes cyclic prefix CP, and fast discrete Fourier change then is carried out to the data obtained frame
It changes FFT and constellation demapping restores to obtain the road N parallel subcarriers, after carrying out error correction decoding to each road parallel subcarriers respectively, into
Row parallel-serial conversion obtains serial data stream, and serial data stream carries out signal and is for conversion into electric signal, is output to customer service output
Interface.
The laser of the transmitting terminal is narrow line width regulatable laser, carries out multi-carrier light transmitting.The narrow linewidth can
Tuned laser spectral line width is less than 1nm, and tuning range is ± 8nm.
The photodetection of the receiving end is directly to carry out intensity detection to the optical signal received in the time domain.
The channel estimation of the receiving end is to track the variation of atmospheric channel shock response and frequency response, to receiving number
According to being corrected and restoring, to compensate channel fading.Known training data sequence X (n) is inserted respectively into N in transmitting terminal
In a subcarrier in the business datum D (n) of each subcarrier n, the value of the training data sequence and position are for sending
End and receiving end are known.It is training data sequence Y (n) after atmospheric channel declines that receiving end is received, is received
End compares Y (n) with known X (n), obtains the estimated value that triplet carrier wave declines through atmospheric channel at this time, receiving end foundation
Current local terminal and the channel and hardware resource of opposite end select a kind of estimation method to recover the moment from training data sequence location
Channel information, after the frequency domain response for estimating atmospheric channel, the channel estimation model at the moment is obtained, by this letter in frequency domain
Road estimates that model carries out interpolation processing to the received business datum R (n) by atmospheric channel decline, recovers the industry of subcarrier
It is engaged in data D (n).
The estimation method of the selection has criterion of least squares (LS), minimum mean square error criterion (MMSE) and maximum likelihood
Estimate estimation methods such as (MLE).Wherein the algorithm complexity of criterion of least squares estimation method is minimum, but performance is poor；It is maximum
The algorithm complexity of Likelihood estimation is moderate, and performance is also medium.It is selected according to the concrete condition of hardware resource and channel
Suitable estimation method.
Preferred plan is minimum mean square error criterion estimation method, and performance is best, meets that channel information is optimal to be wanted
It asks.
The modulation and demodulation of this method realized using DSP special chip, the Error Correction of Coding of transmitting terminal, constellation mapping, quickly
Inverse discrete fourier transform IFFT, add cyclic prefix and add the modulated process of training data sequence dedicated in transmitting terminal DSP
Chip is completed；The channel estimation and signal compensation of receiving end, removal cyclic prefix, fast discrete Fourier transformation FFT, constellation solution
The demodulating process of mapping and error correction decoding is completed in receiving end DSP special chip.
The serioparallel exchange of transmitting terminal obtains the road N parallel subcarriers and completes in the FPGA of transmitting terminal；The parallel-serial conversion of receiving end,
N subcarriers are multiplexed to serial traffic data to complete in the FPGA of receiving end.
To complete modulation, transmitting terminal DSP and receiving end DSP powers on rear sub-carrier number N for the first time, each subcarrier contains
OFDM symbol number, each symbolic number contain bit number number, FFT and IFFT operation points, cyclic prefix occupy OFDM number
The parameters such as the ratio according to frame are configured.Transmitting terminal DSP is according to sub-carrier number and IFFT operation points creation for storing modulation
Data buffer zone after the buffer area of preceding decimal data, modulation, and creation constellation mapping table and each subcarrier data are deposited
Store up space.Receiving end DSP is used to store the buffering of decimal data after demodulation according to sub-carrier number and FFT operation points creation
Area, the preceding data buffer zone of demodulation, and the memory space of creation constellation mapping table and each subcarrier data.Each step process
Acquired results are stored in corresponding buffer area or memory space later.
Fixed storage space is distributed in advance for each subcarrier, is conducive to improve DSP processing operational capability.At each step
Acquired results are stored in corresponding buffer area or memory space after reason.
Compared with prior art, a kind of airborne laser communication method based on OFDM modulation /demodulation of the present invention has following excellent
Point: 1, can completely eliminate intersymbol interference caused by signal multipath transmisstion (ISI) using cyclic prefix (CP) under certain condition,
Destruction of the multipath transmisstion to intercarrier orthogonality is completely eliminated, there is good anti-multipath jamming ability, be effective against atmosphere and disturb
Accidental channel caused by dynamic declines；2. effectively overcome influence of the path difference to system performance, can more overcome aircraft, especially without
Influence of the path length difference of multiple transmission paths to system performance in the case of the man-machine motion of automobile；3, using channel estimation technique, with
The variation of the shock response of track atmospheric channel and frequency response, to receive by atmospheric channel decline data be corrected with it is extensive
It is multiple, obtain performance gain；4, upgrading is convenient, and only need to slightly change in the transmitting terminal of original system and receiving end can be used we
Method, while perfect, improvement system performance, raising are advanced optimized according to airborne circumstance and atmospheric channel condition in subsequent applications
Communication quality；5, the photodetection of receiving end directly carries out intensity detection to the optical signal received in the time domain, this is directly examined
Survey method realizes relatively easy, low-cost and technology maturation；6, Error Correction of Coding is carried out to each subcarriers, improves entangling for system
Wrong ability promotes communication quality, improves communication performance；7, this method is except light-to-current inversion, channel, photoelectric detector, laser hair
It penetrates, outside optical system and mechanical structure, it is most of to be handled in electrical domain, therefore can directly effectively use for reference in radio art
Advanced technology and superior modulation system, such as be effectively reduced peak-to-average power ratio, reduce intersymbol interference, channel estimation is wireless
It has been relatively mature technology in electrical domain, further increase efficiency and communication quality.
Detailed description of the invention
Fig. 1 is the airborne laser communication embodiment of the method key step block diagram based on OFDM modulation /demodulation；
Fig. 2 is the operational process frame based on the airborne laser communication embodiment of the method channel estimation of OFDM modulation /demodulation
Figure.
Specific embodiment
In order to be more clear technical solution of the present invention, with reference to the accompanying drawing, the present invention is described in further detail.
Air craft carried laser communication gear is used for based on the airborne laser communication embodiment of the method for OFDM modulation /demodulation
With its corresponding mutual receiving and transmitting signal of earthbound laser communication equipment, air craft carried laser communication gear and corresponding ground laser
Communication equipment is respectively equipped with a transmitting terminal and a receiving end, is respectively used to transmitting local terminal optical signal and receives opposite end optical signal.
Based on the key step of the airborne laser communication embodiment of the method for OFDM modulation /demodulation as shown in Figure 1, local terminal
Transmitting terminal carries out signal modulation and optical signal launch, and the receiving end of opposite end then receives optical signal and demodulates to signal.
By the electric signal of customer service input interface, using service adapter, (such as clock data is extensive first for the transmitting terminal of local terminal
Multiple chip and signal transformer) it is adapted to the highspeed serial data stream S of LVDS levelin, then passing through FPGA serioparallel exchange module will
Serial data stream becomes the road N parallel subcarriers, and N is the quantity of ofdm system sub-carriers, and this example N=256, FPGA are by N way
Carrier wave is transported to transmitting terminal DSP, and transmitting terminal DSP carries out Error Correction of Coding, constellation mapping to every road signal respectively respectively, then to mapping
Rear data carry out fast discrete Fourier inversion IFFT, later plus cyclic prefix CP and training data sequence, then pass through
Digital-to-analogue conversion (D/A conversion) and low-pass filtering, gained analog electrical signal code stream driving laser are emitted, are passed through atmospheric channel
It is sent to opposite end, atmospheric channel is represented by dashed line in Fig. 1.
The Error Correction of Coding of this example uses cyclic redundancy check code CRC, according to specific multinomial and module-2 division sub-carrier number
It is calculated according to frame, and after calculated result (check code) is attached to subcarrier data frame.
The OFDM of this example is modulated at the QPSK (Quadrature for selecting that the bit error rate is low, realization is relatively easy in constellation mapping
Phase Shift Keying quadrature phase shift keying) modulation system is modulated.
The receiving end of opposite end is first by directly carrying out intensity to the optical signal received in the time domain to signal optical detection
Detection, after obtained electric signal carries out low-pass filtering treatment, then by analog-to-digital conversion, (A/D turns by received analog signal code stream
Change) it is input to receiving end DSP, this example carries out channel estimation and thermal compensation signal using minimum mean square error criterion estimation method, goes
Then cyclic prefix CP carries out fast discrete Fourier transformation FFT and the reduction of constellation demapping, the constellation demapping of this example to it
For QPSK inverse mapping, corresponding value is inquired by planisphere, obtains N subcarriers, then each subcarrier is carried out to carry out error correction solution
Code is input to FPGA progress parallel-serial conversion later and obtains serial data stream Sout, serial data stream SoutSignal is carried out to convert to obtain
Electric signal is output to user traffic interfaces.
The modulation and demodulation of this example realized using DSP special chip, the Error Correction of Coding of transmitting terminal, constellation mapping, quickly from
It dissipates Fourier inversion IFFT plus cyclic prefix and adds the modulated process of training data sequence in the dedicated core of transmitting terminal DSP
Piece is completed；Channel estimation and signal compensation, removal cyclic prefix, fast discrete Fourier transformation FFT, the constellation solution of receiving end are reflected
It penetrates and is completed in receiving end DSP special chip with the demodulating process of error correction decoding.
The serioparallel exchange of transmitting terminal obtains the road N parallel subcarriers and completes in the FPGA of transmitting terminal；The parallel-serial conversion of receiving end,
N subcarriers are multiplexed to serial traffic data to complete in the FPGA of receiving end.
Subcarrier number N=256 is arranged after powering on for the first time in this example transmitting terminal DSP and receiving end DSP, each subcarrier contains
OFDM symbol number be 10, each symbolic number contain 2 bit numbers, FFT and IFFT operation points be 256, cyclic prefix occupy
The ratio of OFDM data frame is 1/10.Before transmitting terminal DSP is used to store modulation according to sub-carrier number and IFFT operation points creation
The memory space of data buffer zone and each subcarrier data after data buffer zone, QPSK constellation mapping table, modulation；Receiving end
DSP according to sub-carrier number and the creation of FFT operation points, for store, delay before the buffer area of decimal data, demodulation after demodulation by data
Rush area, and the memory space of creation QPSK constellation mapping table and each subcarrier data.
The data obtained is stored in corresponding buffer area or memory space after each step process.
Channel estimation operational process in this example is as shown in Fig. 2, before the ifft, the business datum D of transmitting terminal subcarrier n
(n) known training data sequence X (n) is inserted in, is loaded is transmitted into atmospheric channel (with void in Fig. 2 in laser later
Line indicates), receiving end is reached after atmospheric channel declines, that be received is respectively business datum R (n) and training data sequence Y
(n), receiving end is corrected and is restored by channel estimation to receiving data, i.e. signal compensation, to obtain performance gain.It connects
Receiving end by the received training data sequence Y (n) after atmospheric channel declines and known with the consistent training of transmitting terminal
Data sequence X (n) compares, and obtains the estimated value of the channel fading on triplet carrier wave at this time.This example receiving end is according to channel item
Part and hardware resource selection minimum mean square error criterion estimation method recover the channel at the moment from training data sequence location
Information after the frequency domain response for estimating atmospheric channel, obtains the channel estimation model at the moment, this channel estimation is pressed in frequency domain
Model carries out interpolation processing to the received business datum R (n) after atmospheric channel declines, and recovers the industry of data subcarrier
It is engaged in data D ' (n), effective compensation is obtained by channel estimation model when atmospheric channel declines, enough performance gains is obtained, receives
Hold the D (n) of the resulting business datum D ' (n) of recovery and transmitting terminal transmission unanimously, i.e., without error code.
Above-described embodiment is only further described the purpose of the present invention, technical scheme and beneficial effects specific
A example, present invention is not limited to this.All any modifications made within the scope of disclosure of the invention, change equivalent replacement
Into etc., it is all included in the scope of protection of the present invention.
Claims (9)
1. a kind of airborne laser communication method based on OFDM modulation /demodulation, using air craft carried laser communication gear and its phase
The mutual receiving and transmitting signal of earthbound laser communication equipment answered, air craft carried laser communication gear and corresponding earthbound laser communication are set
Standby one transmitting terminal of each outfit and a receiving end are respectively used to transmitting local terminal optical signal and receive opposite end optical signal；Its feature
It is:
The electric signal of customer service input interface is adapted to serial data stream first by the transmitting terminal of local terminal, then simultaneously by string
Serial data is become the road N parallel subcarriers by conversion, and N is the quantity of ofdm system sub-carriers, by the every of the road N parallel subcarriers
Subcarriers carry out Error Correction of Coding, constellation mapping respectively, and the subcarrier after mapping carries out fast discrete Fourier inversion IFFT,
Training data sequence is added in each subcarriers before the ifft or later, which is transmitting terminal and receiving end
The data sequence of known value and position；Finally add cyclic prefix CP again, becomes analog signal code stream by digital-to-analogue conversion, then
Driving laser carries out multi-carrier light transmitting after low-pass filtered, is transmitted to opposite end through atmospheric channel；
The receiving end of opposite end passes through photodetection first and signal light is detected and received, and received signal light is converted to
Electric signal carries out low-pass filtering treatment, obtains analog signal code stream, then carries out analog to digital conversion as digital signal code stream, it is laggard
Row channel estimation and signal compensation remove cyclic prefix CP, then carry out fast discrete Fourier transformation FFT to the data obtained frame
It restores to obtain multidiameter delay subcarrier with constellation demapping, after carrying out error correction decoding to each road parallel subcarriers respectively, carry out simultaneously
String is converted to serial data stream, and serial data stream carries out signal and is for conversion into electric signal, is output to customer service output interface.
2. the airborne laser communication method according to claim 1 based on OFDM modulation /demodulation, it is characterised in that:
The laser of the transmitting terminal is narrow line width regulatable laser, carries out multi-carrier light transmitting.
3. the airborne laser communication method according to claim 2 based on OFDM modulation /demodulation, it is characterised in that:
The narrow line width regulatable laser spectral line width is less than 1nm, and tuning range is ± 8nm.
4. the airborne laser communication method according to claim 1 based on OFDM modulation /demodulation, it is characterised in that:
The photodetection of the receiving end is directly to carry out intensity detection to the optical signal received in the time domain.
5. the airborne laser communication method according to claim 1 based on OFDM modulation /demodulation, it is characterised in that:
The channel estimation of the receiving end be track atmospheric channel shock response and frequency response variation, to receive data into
Row correction and recovery, to compensate channel fading；Known training data sequence X (n) is inserted respectively into N number of son in transmitting terminal
In carrier wave in the business datum D (n) of each subcarrier n, the value of the training data sequence and position are all known；It connects
It is training data sequence Y (n) after atmospheric channel declines that receiving end is received, and receiving end is by Y (n) compared with known X (n)
Compared with obtaining the estimated value that triplet carrier wave declines through atmospheric channel at this time, receiving end is according to current local terminal and the channel of opposite end and hard
Part resource selects a kind of estimation method to recover the channel information at the moment from training data sequence location, estimates atmospheric channel
Frequency domain response after, obtain the channel estimation model at the moment, in frequency domain by this channel estimation model to received through excessive
The business datum R (n) of gas channel fading carries out interpolation processing, recovers the business datum D (n) of subcarrier.
6. the airborne laser communication method according to claim 5 based on OFDM modulation /demodulation, it is characterised in that:
The estimation method of the selection has criterion of least squares, minimum mean square error criterion and maximum Likelihood.
7. the airborne laser communication method according to claim 5 based on OFDM modulation /demodulation, it is characterised in that:
The estimation method of the selection is minimum mean square error criterion estimation method.
8. the airborne laser communication method according to claim 1 based on OFDM modulation /demodulation, it is characterised in that:
The modulation and demodulation of this method is using the realization of DSP special chip, the Error Correction of Coding of transmitting terminal, constellation mapping, fast discrete
Fourier inversion IFFT, add cyclic prefix and add the modulated process of training data sequence in transmitting terminal DSP special chip
It completes；The channel estimation and signal compensation of receiving end, removal cyclic prefix, fast discrete Fourier transformation FFT, constellation demapping
It is completed in receiving end DSP special chip with the demodulating process of error correction decoding；
The serioparallel exchange of transmitting terminal obtains the road N parallel subcarriers and completes in the FPGA of transmitting terminal；The parallel-serial conversion of receiving end, by N
Subcarriers are multiplexed to serial traffic data and complete in the FPGA of receiving end.
9. the airborne laser communication method according to claim 8 based on OFDM modulation /demodulation, it is characterised in that:
The OFDM symbol that the transmitting terminal DSP and receiving end DSP powers on rear sub-carrier number N for the first time, each subcarrier contains
Bit number number that several, each symbolic number contains, FFT and IFFT operation points, cyclic prefix occupy the ratio of OFDM data frame
Parameter configured；Decimal number before transmitting terminal DSP is modulated according to sub-carrier number and IFFT operation points creation for storage
According to data buffer zone after buffer area, modulation, and the memory space of creation constellation mapping table and each subcarrier data；Receiving end
DSP according to sub-carrier number and the creation of FFT operation points, for store, delay before the buffer area of decimal data, demodulation after demodulation by data
Rush area, and the memory space of creation constellation mapping table and each subcarrier data；Gained is tied after each step process
Fruit is stored in corresponding memory space；The data obtained is stored in corresponding buffer area or memory space after each step process.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811618434.2A CN109495174A (en) | 2018-12-28 | 2018-12-28 | A kind of airborne laser communication method based on OFDM modulation /demodulation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811618434.2A CN109495174A (en) | 2018-12-28 | 2018-12-28 | A kind of airborne laser communication method based on OFDM modulation /demodulation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN109495174A true CN109495174A (en) | 2019-03-19 |
Family
ID=65712786
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811618434.2A Pending CN109495174A (en) | 2018-12-28 | 2018-12-28 | A kind of airborne laser communication method based on OFDM modulation /demodulation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109495174A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111371722A (en) * | 2020-03-18 | 2020-07-03 | 南京创远信息科技有限公司 | Method for realizing predistortion compensation processing aiming at 5G NR in-band modulation signal |
| CN112350746A (en) * | 2020-09-28 | 2021-02-09 | 南京瑞贻电子科技有限公司 | Channel weakening detection system and method for power line carrier communication system |
| CN113658352A (en) * | 2021-07-07 | 2021-11-16 | 中国人民解放军海军航空大学青岛校区 | Airborne flight parameter signal adapting device |
| CN114199075A (en) * | 2021-12-21 | 2022-03-18 | 北京华如科技股份有限公司 | Chest ring target simulation laser training system |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1725749A (en) * | 2005-07-12 | 2006-01-25 | 南开大学 | Communication system with very-high frequency and ultrahigh frequency band high frequency band availability |
| CN101257471A (en) * | 2008-03-31 | 2008-09-03 | 浙江大学 | Mobile multimedia digital broadcast OFDM system channel estimation method |
| CN101562596A (en) * | 2009-05-26 | 2009-10-21 | 北京理工大学 | Onboard high-speed communication system based on OFDM technique |
| CN101958871A (en) * | 2010-09-16 | 2011-01-26 | 西安工业大学 | Adaptive free space optical communication (FSO)-orthogonal frequency division multiplexing (OFDM) transmission system and transmission method |
| JP2012238931A (en) * | 2011-05-09 | 2012-12-06 | Kyocera Corp | Communication system, optical communication device, main base station, auxiliary base station, and radio terminal |
| CN103986680A (en) * | 2014-05-14 | 2014-08-13 | 北京航空航天大学 | Miniaturization dual-channel OFDM communication system and achieving method of miniaturization dual-channel OFDM communication system |
| CN104333527A (en) * | 2014-11-26 | 2015-02-04 | 西安烽火电子科技有限责任公司 | COFDM (Coded Orthogonal Frequency Division Multiplexing) modulating and demodulating method used for airplane |
| CN104426828A (en) * | 2013-08-26 | 2015-03-18 | 西北工业技术研究院 | Realization method of airborne burst C-OFDM system |
| CN108234028A (en) * | 2017-12-19 | 2018-06-29 | 复旦大学 | A kind of light quantum ofdm communication system and its quantum information detection method |
-
2018
- 2018-12-28 CN CN201811618434.2A patent/CN109495174A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1725749A (en) * | 2005-07-12 | 2006-01-25 | 南开大学 | Communication system with very-high frequency and ultrahigh frequency band high frequency band availability |
| CN101257471A (en) * | 2008-03-31 | 2008-09-03 | 浙江大学 | Mobile multimedia digital broadcast OFDM system channel estimation method |
| CN101562596A (en) * | 2009-05-26 | 2009-10-21 | 北京理工大学 | Onboard high-speed communication system based on OFDM technique |
| CN101958871A (en) * | 2010-09-16 | 2011-01-26 | 西安工业大学 | Adaptive free space optical communication (FSO)-orthogonal frequency division multiplexing (OFDM) transmission system and transmission method |
| JP2012238931A (en) * | 2011-05-09 | 2012-12-06 | Kyocera Corp | Communication system, optical communication device, main base station, auxiliary base station, and radio terminal |
| CN104426828A (en) * | 2013-08-26 | 2015-03-18 | 西北工业技术研究院 | Realization method of airborne burst C-OFDM system |
| CN103986680A (en) * | 2014-05-14 | 2014-08-13 | 北京航空航天大学 | Miniaturization dual-channel OFDM communication system and achieving method of miniaturization dual-channel OFDM communication system |
| CN104333527A (en) * | 2014-11-26 | 2015-02-04 | 西安烽火电子科技有限责任公司 | COFDM (Coded Orthogonal Frequency Division Multiplexing) modulating and demodulating method used for airplane |
| CN108234028A (en) * | 2017-12-19 | 2018-06-29 | 复旦大学 | A kind of light quantum ofdm communication system and its quantum information detection method |
Non-Patent Citations (1)
| Title |
|---|
| 王涵: ""Gamma-Gamma大气湍流下FSO-OFDM调制***研究"", 《中国优秀硕士学位论文全文数据库 信息科技辑》 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111371722A (en) * | 2020-03-18 | 2020-07-03 | 南京创远信息科技有限公司 | Method for realizing predistortion compensation processing aiming at 5G NR in-band modulation signal |
| CN112350746A (en) * | 2020-09-28 | 2021-02-09 | 南京瑞贻电子科技有限公司 | Channel weakening detection system and method for power line carrier communication system |
| CN112350746B (en) * | 2020-09-28 | 2021-08-10 | 南京瑞贻电子科技有限公司 | Channel weakening detection system and method for power line carrier communication system |
| CN113658352A (en) * | 2021-07-07 | 2021-11-16 | 中国人民解放军海军航空大学青岛校区 | Airborne flight parameter signal adapting device |
| CN114199075A (en) * | 2021-12-21 | 2022-03-18 | 北京华如科技股份有限公司 | Chest ring target simulation laser training system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109495174A (en) | A kind of airborne laser communication method based on OFDM modulation /demodulation | |
| KR100854830B1 (en) | Communications systems and methods using phase vectors | |
| CN101496332B (en) | The method and apparatus of multicarrier MIMO channel performance is improved with Hadamard transform | |
| US8559994B2 (en) | Multi-antenna scheduling system and method | |
| CN105591717B (en) | The low complex degree detection method of MIMO-OFDM system for carrier index modulation | |
| EP1806893A2 (en) | Apparatus and method for communicating data in hybrid diversity mode in broadband wireless communication system | |
| Xu et al. | Nyquist-SEFDM: Pulse shaped multicarrier communication with sub-carrier spacing below the symbol rate | |
| US7953164B2 (en) | System and method for performing LS equalization on a signal in an OFDM system | |
| NL2012479A (en) | Device and Method for Predistortion. | |
| Yang et al. | Spectrum-efficient index modulation with improved constellation mapping | |
| Schaich et al. | A reduced complexity receiver for multi-carrier faster-than-Nyquist signaling | |
| Zhou et al. | Non-orthogonal discrete multi-tone: toward higher spectral efficiency for optical networks | |
| CN101141167A (en) | Single carrier frequency domain equalization method and system in DFT-CDMA system | |
| US7693224B2 (en) | Subcarrier adaptive thresholding | |
| Belallou et al. | OFDM-subcarrier power modulation with two dimensional signal constellations | |
| Liu et al. | Profile-based power allocation in OFDM with index modulation | |
| Samal et al. | 5G communication networks and modulation schemes for next-generation smart grids | |
| KR100840618B1 (en) | Close loop transmission method and apparatus | |
| Chaki et al. | Precoded non-orthogonal frequency division multiplexing with subcarrier index modulation | |
| Acar et al. | Data detection based iterative channel estimation for coded SM-OFDM systems | |
| Patil et al. | Performance evaluation of large MIMO | |
| KR102646781B1 (en) | Media-based modulation aided uplink Non-orthogonal Multiple Access System | |
| Chen et al. | Iterative receiver for mobile MIMO-OFDM systems using ICI-aware list-update MIMO detection | |
| KR101225649B1 (en) | Apparatus and method for channel estimation in multiple antenna communication system | |
| CN102714849A (en) | Optimizing downlink communications between a base station and a remote terminal by power sharing |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20190319 |
|
| WD01 | Invention patent application deemed withdrawn after publication |