CN107018105B - Underwater visible light communication method and system - Google Patents
Underwater visible light communication method and system Download PDFInfo
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- CN107018105B CN107018105B CN201710255229.3A CN201710255229A CN107018105B CN 107018105 B CN107018105 B CN 107018105B CN 201710255229 A CN201710255229 A CN 201710255229A CN 107018105 B CN107018105 B CN 107018105B
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- 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
- H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
- H04L25/03006—Arrangements for removing intersymbol interference
- H04L25/03343—Arrangements at the transmitter end
-
- 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
- H04B10/114—Indoor or close-range type systems
- H04B10/116—Visible light communication
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- 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
- H04B10/60—Receivers
- H04B10/66—Non-coherent receivers, e.g. using direct detection
- H04B10/69—Electrical arrangements in the receiver
- H04B10/697—Arrangements for reducing noise and distortion
- H04B10/6971—Arrangements for reducing noise and distortion using equalisation
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- 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
- H04B10/80—Optical aspects relating to the use of optical transmission for specific applications, not provided for in groups H04B10/03 - H04B10/70, e.g. optical power feeding or optical transmission through water
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- 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
- H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
- H04L25/03006—Arrangements for removing intersymbol interference
- H04L2025/03592—Adaptation methods
- H04L2025/03598—Algorithms
- H04L2025/03611—Iterative algorithms
- H04L2025/03617—Time recursive algorithms
- H04L2025/03624—Zero-forcing
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- 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
- H04L25/0204—Channel estimation of multiple channels
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- 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
- H04L25/0212—Channel estimation of impulse response
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—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
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—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
Abstract
The embodiment of the invention discloses a kind of system of underwater visible light communication methods and applications this method, method includes: the impulse response function for obtaining the underwater channel for being used for transmission signal；Impulse response function is sampled, characteristic of channel matrix is obtained；By inverse Fourier transform IFFT by signal modulation to be transmitted to multiple subcarriers, and each subcarrier through ovennodulation is split into multiple blocks；Zero padding amount is determined according to the sampling quantity of impulse function, and zero padding processing is carried out according to end of the zero padding amount to each block；Serial data will be formed by the block of zero padding processing, and serial data is sent to optical signal source, to generate visible light signal；Electric signal is generated according to visible light signal, and zero forcing equalization processing is carried out to the serial signal according to characteristic of channel matrix；Fourier transformation FFT will be carried out by the signal of zero forcing equalization processing, and recovers the signal to be transmitted.Communication efficiency and quality can be taken into account, is with a wide range of applications.
Description
Technical field
The present invention relates to wireless communication technology field, in particular to a kind of underwater visible light communication method and system.
Background technique
Currently, a kind of underwater visible light communication technology using underwater dissemination channel visible light, leads in business and military affairs etc.
Domain has great application prospect.However, absorbing and scattering since water generates visible light, such case will cause transmitting photon
The time delay for reaching receiver is different, in turn results in intersymbol interference, receives underwater visible light communication in transmission performance
Certain restriction.Especially during the underwater visible light communication of long range, intersymbol interference can seriously affect communication system
Performance influences communication quality.
Summary of the invention
The purpose of the embodiment of the present invention is that a kind of underwater visible light communication method and system are provided, to solve the above problems.
In order to solve the above technical problems, the embodiment of the present invention provides a kind of underwater visible light communication method, comprising:
Obtain the impulse response function for being used for transmission the underwater channel of signal；
The impulse response function is sampled, characteristic of channel matrix is obtained；
By inverse Fourier transform IFFT by signal modulation to be transmitted to multiple subcarriers, and by each son through ovennodulation
Carrier wave splits into multiple blocks；
Determine zero padding amount according to the sampling quantity of the impulse function, and according to the zero padding amount to the end of each block into
Row zero padding processing；
Serial data will be formed by the block of zero padding processing, and the serial data is sent to optical signal source, with
Generate visible light signal；
Electric signal is generated according to the visible light signal, and the serial signal is carried out according to the characteristic of channel matrix
Zero forcing equalization processing；
Fourier transformation FFT will be carried out by the signal of zero forcing equalization processing, and recovers the signal to be transmitted.
Preferably, the impulse response function for obtaining the underwater channel, specifically includes:
Double gamma functions of the underwater channel are obtained, double gamma functions include unknown parameter；
Obtain the Monte Carlo simulation result for being directed to the underwater channel；
Unknown parameter in double gamma functions is determined by the Monte Carlo simulation result, and with double after determination
Impulse response function of the gamma function as the underwater channel.
Preferably, the impulse response function is sampled, before obtaining characteristic of channel matrix, the method is also wrapped
It includes:
The channel impulse function is lower than 10-10Data be directly disposed as 0 value.
Preferably, the zero padding amount subtracts one equal to sampling quantity.
Preferably, the underwater communications system is ofdm communication system.
In order to solve the above technical problems, the embodiment of the present invention provides a kind of underwater visible light communication system, comprising:
Processor, for obtaining the impulse response function for being used for transmission the underwater channel of signal；
The processor obtains characteristic of channel matrix for sampling to the impulse response function；
Transmitter, for by inverse Fourier transform IFFT by signal modulation to be transmitted to multiple subcarriers, and will be through
Each subcarrier of ovennodulation splits into multiple blocks；
The transmitter is also used to determine zero padding amount according to the sampling quantity of the impulse function, and according to the zero padding amount
Zero padding processing is carried out to the end of each block；
The transmitter is also used to that serial data will be formed by the block of zero padding processing；
Optical signal source, for receiving the serial data and generating visible light signal accordingly；
Receiver, for generating electric signal according to the visible light signal, and according to the characteristic of channel matrix to described
Serial signal carries out zero forcing equalization processing；
The receiver is also used to that Fourier transformation FFT will be carried out by the signal of zero forcing equalization processing, and recovers institute
State signal to be transmitted.
Preferably, the processor, is specifically used for:
Double gamma functions of the underwater channel are obtained, double gamma functions include unknown parameter；
Obtain the Monte Carlo simulation result for being directed to the underwater channel；
Unknown parameter in double gamma functions is determined by the Monte Carlo simulation result, and with double after determination
Impulse response function of the gamma function as the underwater channel.
Preferably, the transmitter, is also used to:
The channel impulse function is lower than 10-10Data be directly disposed as 0 value.
Preferably, the zero padding amount subtracts one equal to sampling quantity.
Preferably, the underwater communications system is ofdm communication system.
As the above technical solution provided in an embodiment of the present invention as it can be seen that underwater visible light provided by the embodiment of the present invention leads to
Believe method and system, is a kind of more suitably selection by communication system of the OFDM modulation technique in conjunction with zero padding, force zero, especially
It is that can take into account communication efficiency with the advantage that conventional modulated technology is incomparable under high bit rate and severe channel circumstance
And quality, it is with a wide range of applications.
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
The some embodiments recorded in invention, for those of ordinary skill in the art, in the premise of not making the creative labor property
Under, it is also possible to obtain other drawings based on these drawings.
Fig. 1 is the flow chart of underwater visible light communication method in the embodiment of the present invention.
Fig. 2 is the tool for obtaining the impulse response function of underwater channel in the embodiment of the present invention in underwater visible light communication method
Body flow chart.
Fig. 3 is the schematic diagram of zero padding block in underwater visible light communication method in the embodiment of the present invention.
Fig. 4 is the module map of underwater visible light communication system in the embodiment of the present invention.
Specific embodiment
Technical solution in order to enable those skilled in the art to better understand the present invention, below in conjunction with of the invention real
The attached drawing in example is applied, technical scheme in the embodiment of the invention is clearly and completely described, it is clear that described implementation
Example is only a part of the embodiment of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, this field is common
Technical staff's every other embodiment obtained without making creative work, all should belong to protection of the present invention
Range.
Fig. 1 is the flow chart of underwater visible light communication method in the embodiment of the present invention, and this method can be applied under water may be used
Light-exposed communication system, the underwater communications system can be ofdm communication system.The optical communication system includes transmitter, receives
Machine and the underwater channel between the transmitter and receiver.This method specifically includes step 101 to 107.
In a step 101, the impulse response function of the underwater channel is obtained.
Under water in visible light communication technology, underwater channel is difficult to keep centainly, with the depth of seawater, muddy limpid etc.
Multiple element is associated.In embodiments of the present invention, first during executing underwater visible light communication method of the present invention
The impulse response function for first obtaining underwater channel characterizes the photon by the underwater transmission by the impulse response function
Attenuation loss.
As shown in connection with fig. 2, in the present embodiment, step 101 specifically comprises the following steps 111 to 113.Below in conjunction with as follows
Sub-step is described in detail the generating process of the impulse response function of underwater channel.
In step 111, double gamma Gamma functions of the underwater channel are obtained, double gamma functions include unknown
Parameter.
Double gamma functions can be used for describing the impulse response function of underwater channel due to its mathematical characteristic.In this implementation
In example, impulse response function
Wherein L is the transmission range between transceiver, and v is the underwater transmission speed of light of respective wavelength, four parameter C1
To C4It is then unknown parameter.
In step 112, the Monte Carlo simulation result for being directed to the underwater channel is obtained.
Monte Carlo simulation is the result is that by Monte-carlo Simulation Method to the imitative of the impulse response function of the underwater channel
True result.By the way that the underwater channel series of parameters (such as turbidity, depth of water etc.) is inputted Monte Carlo analysis model
Determine the Monte Carlo simulation result for the underwater channel.
In step 113, unknown parameter in double gamma functions is determined by the Monte Carlo simulation result, and
Using double gamma functions after determination as the impulse response function of the underwater channel.
Due to being to pass through Monte Carlo for same underwater channel by double gamma functions and Monte Carlo simulation result
Simulation result can determine each unknown parameter C in impulse response function h (t) that double gamma functions are determined1To C4。
In embodiments of the present invention, each unknown parameter C in impulse function h (t) can be determined by graphical approximation method1Extremely
C4.I.e. by adjusting C1To C4Value so that the formed figure of impulse function h (t) constantly approaches Monte Carlo simulation as a result, most
Afterwards after two graphics overlays, C is determined1To C4Value.
Determining unknown parameter C1To C4Afterwards, using double gamma function h (t) after determination as the impulse of the underwater channel
Receptance function.
In a step 102, the impulse response function is sampled, obtains characteristic of channel matrix.
After determining impulse response function h (t), impulse response function h (t) is sampled, obtains the letter of underwater channel
Road feature matrix h=[h (0), h (1) ..., h (P-1)]T, character rate Rs=1/ Δ t, using time Δ t as the sampling interval.It adopts
Impulse response function h (t) after sample can be understood as the approximate FIR channel model with P rank channel coefficients.Implement in the present invention
In example, the channel impulse function is lower than 10-10Data be directly disposed as 0 value, then the signal after truncation is sampled.
In step 103, by inverse Fourier transform IFFT by signal modulation to be transmitted to multiple subcarriers, and will be through
Each subcarrier of ovennodulation splits into multiple blocks.
After signal to be transmitted enters transmitter, after digital modulation, Hermitian symmetrical treatment, IFFT processing is carried out,
To which signal modulation to be transmitted to multiple subcarriers, is obtained time-domain signal.Each subcarrier is default, is orthogonal between each other
, to prevent each subcarrier from interfering with each other.
After obtaining brewed each subcarrier, each sub-carrier signal is split, obtains multiple blocks, Mei Gexin
Number block includes multiple symbols.In embodiments of the present invention, the quantity of block can be with the sampling of impulse Response Function h (t)
It is identical to measure P.
If individual signals block is expressed as x=[x1,x2,...,xN1], then the signal calculation formula of receiver
Wherein n is white Gaussian noise vector, mean value 0, variance σ2.By the convolution of h (t) and x, the machine of can be received is received
The signal arrived.
At step 104, zero padding amount is determined according to the sampling quantity of the impulse function, and according to the zero padding amount to each letter
The end of number block carries out zero padding processing.
When in order to eliminate block transmission, carried out by interference between each block for being generated after channel and signal same
Step adds L zero-signal of zero padding amount at each block end, by the way that interval mends one at regular intervals in the data of transmission
Long serial data is divided into block section one by one by the signal value of zero of fixed number amount, thus dry between block and block to eliminate
It disturbs, and reduces the difficulty of signal detection in each block.
After being handled by zero padding, block is converted to s=[s1, s2... sN2, 0,0 ... 0]T, so the block after zero padding
Transmission system model can be written as r=Hs+ ξ.
Wherein, individually sending block in the corresponding r in receiving end is (a N2+ L) × 1 reception signal phasor, ξ be plus
Property white Gaussian noise vector, mean value 0, variance σ2, H is according to (N2+L)×N2The Top benefit thatch Toeplitz generated
Matrix, Toeplitz matrix form are as follows:
If P >=L, mutual superposition is always had between the non-zero symbol of adjacent signals block, that is, inter-block-interference occurs.So
We set the order that the zero padding amount L mesh added after block is always less than channel coefficients, i.e. P≤L, the then interference between block
It all is distributed in zero point interval, the inter-block-interference of block is not present, that is, eliminates inter-block-interference.But zero padding amount L excessively can
There is transmitting redundancy, reduces transmission rate, therefore we generally enable P=L in the ideal case.Behind transmitting terminal is due to block of channels
The end zero padding of introducing and channel convolution, in receiving end, each block is converted to (N2+ P-1) a symbol, (L-p+ is followed at end
1) a zero point, extra zero point can be used for further splitting signal after each block of receiving terminal, eliminate ignored smaller
Inter-block-interference.Therefore the block of the indefinite length sent can be expressed as.
X=[x (1), x (2), x (3) ... x (N), 0,0 ..., 0, x (N+L+1) ..., x (N+L+N), 0,0 ..., 0, x (N+L
+ N+L+1) ...] (2)
The data eventually received can be expressed as
It can see from the data structure of receiving end, according to channel coefficients and the zero padding after each block, Neng Goubao
It is divided and comes between card block, and the number of zero padding, that is, the distance divided can then detect the difficulty of signal according to receiving end
Yi Du is adjusted.Receiving end zero point quantity physical relationship is as follows:
Such as: channel coefficients block (1,1,1,1), block (1,1,1,1)=(1,1,1,1,1,1,1).It is required that requiring letter
The zero padding amount L of road coefficient block P and block will meet formula (4), otherwise the result zero point after convolution.The nothing for causing information to transmit
Effect and redundancy.
In step 105, serial data will be formed by the block of zero padding processing, and the serial data is sent to
Optical signal source, to generate visible light signal.
In embodiments of the present invention, parallel-serial conversion is carried out by zero padding treated block, forms one group of serial data,
For the serial data using optical signal source is sent to after digital-to-analogue conversion, direct current biasing, optical signal source generates visible light signal accordingly.
Wherein, optical signal source can make LED light source etc..
In step 106, electric signal is generated according to the visible light signal, and according to the characteristic of channel matrix to described
Serial signal carries out zero forcing equalization processing.
After receiver receives visible light signal, realized for example, by PD receiver it will be seen that optical signal is converted to simulation
Electric signal, and then zero forcing equalization processing is entered according to analog-to-digital conversion, serioparallel exchange.By determining zero padding amount on each subcarrier
L zero-signal, realization cut out each block.
In step 107, Fourier transformation FFT will be carried out by the signal of zero forcing equalization processing, and recover it is described to
Transmit signal.
Certainly, after FFT is handled, it is also necessary to carry out the processing such as digital demodulation, parallel-serial conversion, this will not be repeated here.
The technical advantage of underwater visible light communication method is provided below in conjunction with the present invention is described in detail.Implement in the present invention
In example, each subcarrier sends end signalQAM modulation generally is used, if each symbol is independently and randomly taken fromRank QAM constellation, r1The bit number for including for each symbol.
Data are sent after IFFT is converted, sub-carrier carries out zero padding design, and M rank QAM signal is every in zero padding system
A data block is expressed as follows shown in figure, whereinK=r1。
It is transmitting signal element according to each data block of Fig. 3, each subcarrier average emitted power should be taken when calculating signal-to-noise ratio
Are as follows:
Wherein E represents the average energy of each signal.Zero padding block transmission system non-for a QAM, each subcarrier
Average transmission bit rate calculation formula are as follows:
Wherein Δ t represents the temporal resolution of channel coefficients h, and P is the tap coefficient number in the during this period of time portion h, i.e.,
The number of samples of channel impulse response.And for a QAM zero padding block transmission system, each subcarrier average transmission bit rate
Calculation formula are as follows:
It can see from formula (7), zero padding can reduce effective transmitted bit rate, especially when there are the expansions of strong time for channel
When dissipating, more zero padding numbers are needed, L increases, bit rate η2It reduces.Meanwhile after the order of modulation of QAM signal determines, mend
The bit rate of zero system just determines by zero padding number L, and in order to guarantee that the ISI between data block is only in mono- area zero padding Na
Domain must have L > P-1 by formula (4) without influence on useful signal region.Simultaneously in order to obtain highest transmission rate, by
Formula (7) L should be as small as possible, so we generally enable L=P.Then in zero padding system each subcarrier highest transfer ratio
Special rate are as follows:
Above formula can convert are as follows:
In above formula, T is the duration of channel impulse response.
Similarly, L=0 in (9) is allowed, obtaining on each subcarrier M rank QAM in the mean bitrate of non-zero padding system is
One fixed value:
Formula (9) (10) is obtained into zero padding and non-zero padding system with the increasing of the increased bit rate of channel coefficients to P derivation
Long rate are as follows:
Further analytical formula (6) (7), when signal transmission rate is continuously increased, i.e. the order P of channel coefficients constantly increases
Add, then for non-zero padding system transmitted bit rate η1It is proportional to P value and tends to be infinitely great, and the highest ratio of zero padding system
Special rate can tend to a definite value, i.e., the following limit of convergence:
Simultaneously to the variable P value derivation of formula (6) (8) after, it can be seen that the bit rate growth rate of non-zero padding system be consolidate
Fixed, for system with the increase of channel coefficients, bit rate can be with steady growth.And the transmission rate of zero padding system is due to being mended
The influence of zero-length, with the continuous improvement of character rate, the growth rate of bit rate can be smaller and smaller, and there are the upper limits.
It is above prove the result shows that: under water in visible light communication technology, traditional modulation technique cannot expire completely
The actual communication of foot needs, and is a kind of more suitably choosing by communication system of the OFDM modulation technique in conjunction with zero padding, force zero
It selects, with the advantage that conventional modulated technology is incomparable especially under high bit rate and severe channel circumstance, can take into account
Communication efficiency and quality, are with a wide range of applications.
Fig. 4 is the module map of underwater visible light communication system in the embodiment of the present invention.The underwater visible light communication system
Working principle can not make expansion description with reference to communication means in previous embodiment herein.The underwater visible light communication system, packet
It includes:
Processor 201, for obtaining the impulse response function for being used for transmission the underwater channel of signal；
The processor 201 obtains characteristic of channel matrix for sampling to the impulse response function；
Transmitter 202, for passing through inverse Fourier transform IFFT for signal modulation to be transmitted to multiple subcarriers, and will
Each subcarrier through ovennodulation splits into multiple blocks；
The transmitter 202 is also used to determine zero padding amount according to the sampling quantity of the impulse function, and according to the zero padding
It measures and zero padding processing is carried out to the end of each block；
The transmitter 202 is also used to that serial data will be formed by the block of zero padding processing；
Optical signal source 203, for receiving the serial data and generating visible light signal accordingly；
Receiver 204, for generating electric signal according to the visible light signal, and according to the characteristic of channel matrix to institute
It states serial signal and carries out zero forcing equalization processing；
The receiver 204 is also used to that Fourier transformation FFT will be carried out by the signal of zero forcing equalization processing, and restores
The signal to be transmitted out.
In practical applications, can be by the way that zero padding module be arranged in transmitter 202, setting force zero is equal in receiver 204
Weighing apparatus processing module come realize aforementioned zero padding and zero forcing equalization processing, the position of the two modules can be embedding according to signal processing order
Enter traditional ofdm communication system, this will not be repeated here.
Preferably, the processor 201, is specifically used for:
Double gamma functions of the underwater channel are obtained, double gamma functions include unknown parameter；
Obtain the Monte Carlo simulation result for being directed to the underwater channel；
Unknown parameter in double gamma functions is determined by the Monte Carlo simulation result, and with double after determination
Impulse response function of the gamma function as the underwater channel.
Preferably, the transmitter 202, is also used to:
The channel impulse function is lower than 10-10Data be directly disposed as 0 value.
Preferably, the zero padding amount subtracts one equal to sampling quantity.
Preferably, the underwater communications system is ofdm communication system.
To sum up, as the above technical solution provided in an embodiment of the present invention as it can be seen that under water may be used provided by the embodiment of the present invention
Light-exposed communication system is a kind of more suitably selection by communication system of the OFDM modulation technique in conjunction with zero padding, force zero, especially
It is that can take into account communication efficiency with the advantage that conventional modulated technology is incomparable under high bit rate and severe channel circumstance
And quality, it is with a wide range of applications.
All the embodiments in this specification are described in a progressive manner, same and similar portion between each embodiment
Dividing may refer to each other, and each embodiment focuses on the differences from other embodiments.Especially for system reality
For applying example, since it is substantially similar to the method embodiment, so being described relatively simple, related place is referring to embodiment of the method
Part explanation.
The above description is only an embodiment of the present invention, is not intended to restrict the invention.For those skilled in the art
For, the invention may be variously modified and varied.All any modifications made within the spirit and principles of the present invention are equal
Replacement, improvement etc., should be included within scope of the presently claimed invention.
Claims (8)
1. a kind of underwater visible light communication method, which is characterized in that the described method includes:
Obtain the impulse response function for being used for transmission the underwater channel of signal；
The impulse response function is sampled, characteristic of channel matrix is obtained；
By inverse Fourier transform IFFT by signal modulation to be transmitted to multiple subcarriers, and by each subcarrier through ovennodulation
Split into multiple blocks；
Determine zero padding amount according to the sampling quantity of the impulse response function, and according to the zero padding amount to the end of each block into
Row zero padding processing；
Serial data will be formed by the block of zero padding processing, and the serial data is sent to optical signal source, to generate
Visible light signal；
Electric signal is generated according to the visible light signal, and force zero is carried out to the serial signal according to the characteristic of channel matrix
Equilibrium treatment；
Fourier transformation FFT will be carried out by the signal of zero forcing equalization processing, and recovers the signal to be transmitted；
Wherein, the zero padding amount subtracts one equal to sampling quantity.
2. underwater visible light communication method as described in claim 1, which is characterized in that the impulse for obtaining the underwater channel is rung
Function is answered, is specifically included:
Double gamma functions of the underwater channel are obtained, double gamma functions include unknown parameter；
Obtain the Monte Carlo simulation result for being directed to the underwater channel；
Unknown parameter in double gamma functions is determined by the Monte Carlo simulation result, and with double gammas after determination
Impulse response function of the function as the underwater channel.
3. underwater visible light communication method as described in claim 1, which is characterized in that adopted to the impulse response function
Sample, before obtaining characteristic of channel matrix, the method also includes:
The impulse response function is lower than 10-10Data be directly disposed as 0 value.
4. underwater visible light communication method as described in claim 1, which is characterized in that the underwater communications system is logical for OFDM
Letter system.
5. a kind of underwater visible light communication system characterized by comprising
Processor, for obtaining the impulse response function for being used for transmission the underwater channel of signal；
The processor obtains characteristic of channel matrix for sampling to the impulse response function；
Transmitter, for passing through inverse Fourier transform IFFT for signal modulation to be transmitted to multiple subcarriers, and will be through toning
Each subcarrier of system splits into multiple blocks；
The transmitter is also used to determine zero padding amount according to the sampling quantity of the impulse response function, and according to the zero padding amount
Zero padding processing is carried out to the end of each block；
The transmitter is also used to that serial data will be formed by the block of zero padding processing；
Optical signal source, for receiving the serial data and generating visible light signal accordingly；
Receiver, for generating electric signal according to the visible light signal, and according to the characteristic of channel matrix to described serial
Signal carries out zero forcing equalization processing；
The receiver is also used to that Fourier transformation FFT will be carried out by the signal of zero forcing equalization processing, and recover it is described to
Transmit signal；
Wherein, the zero padding amount subtracts one equal to sampling quantity.
6. underwater visible light communication system as claimed in claim 5, which is characterized in that the processor is specifically used for:
Double gamma functions of the underwater channel are obtained, double gamma functions include unknown parameter；
Obtain the Monte Carlo simulation result for being directed to the underwater channel；
Unknown parameter in double gamma functions is determined by the Monte Carlo simulation result, and with double gammas after determination
Impulse response function of the function as the underwater channel.
7. underwater visible light communication system as claimed in claim 5, which is characterized in that the transmitter is also used to:
The impulse response function is lower than 10-10Data be directly disposed as 0 value.
8. underwater visible light communication system as claimed in claim 5, which is characterized in that the underwater communications system is logical for OFDM
Letter system.
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| CN111555822B (en) * | 2020-04-28 | 2021-08-20 | 西安邮电大学 | Phase screen-based underwater wireless light transmission Monte Carlo simulation method |
| CN111723478B (en) * | 2020-06-11 | 2023-03-24 | 河海大学 | Clear ocean water quality UWOC system channel impulse response fitting function solving method and system |
| CN111726307B (en) * | 2020-06-11 | 2022-02-11 | 河海大学 | Iterative initial value solving method and system for LS (least squares) fitting coefficient of double gamma functions of channel impulse response |
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