CN109309638A - Approach for blind channel equalization and device, computer storage medium and calculating equipment - Google Patents
Approach for blind channel equalization and device, computer storage medium and calculating equipment Download PDFInfo
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- CN109309638A CN109309638A CN201710620330.4A CN201710620330A CN109309638A CN 109309638 A CN109309638 A CN 109309638A CN 201710620330 A CN201710620330 A CN 201710620330A CN 109309638 A CN109309638 A CN 109309638A
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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
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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
- H04B10/61—Coherent receivers
- H04B10/616—Details of the electronic signal processing in coherent optical receivers
- H04B10/6162—Compensation of polarization related effects, e.g., PMD, PDL
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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
- H04L25/03159—Arrangements for removing intersymbol interference operating in the frequency domain
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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
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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
- H04L2025/03681—Control of adaptation
- H04L2025/03687—Control of adaptation of step size
Abstract
The invention discloses a kind of approach for blind channel equalization and devices, computer storage medium and calculating equipment, to solve the problems, such as channel equalization method in the prior art, there are system spectrum utilization rate is low, this method are as follows: pre-processed for the ofdm signal received, after obtaining N number of OFDM symbol, successively obtain the destination channel frequency response inverse matrix of each subcarrier, utilize the destination channel frequency response inverse matrix and frequency domain data of each subcarrier, restore the data that transmitting terminal is sent on corresponding subcarrier, during obtaining destination channel frequency response inverse matrix, iteration step length when iteration optimization is adaptively adjusted using estimation error, accelerate the convergence rate of iteration optimization, improve the efficiency of algorithm for blind channel equalization, and, restoring the data that transmitting terminal is sent on each subcarrier using destination channel frequency response inverse matrix During, without using pilot signal or training sequence, effectively improve system spectrum utilization rate.
Description
Technical field
The present invention relates to field of communication technology more particularly to a kind of approach for blind channel equalization and device, computer storage to be situated between
Matter and calculating equipment.
Background technique
Currently, orthogonal frequency division multiplexing (Orthogonal Frequency Division Multiplexing, OFDM) skill
The advantages that art is with its higher availability of frequency spectrum, flexible system injury compensation way and good dispersion rejection ability,
One of the technology being concerned as fields such as high speed long haul communications systems and optical transmission systems.Wherein, palarization multiplexing is relevant
Light orthogonal frequency division multiplexing (Polarization Division Multiplexed-Coherent Optical-OFDM, PDM-
CO-OFDM the characteristics of) system can support two polarization state simultaneous transmissions using single mode optical fiber, by palarization multiplexing
(Polarization Division Multiplexed, PDM) technology is used for coherent light orthogonal frequency division multiplexing (Coherent
Optical-OFDM, CO-OFDM) in system, double up transmission rate.
However, PDM-CO-OFDM system is by polarization mode dispersion (Polarization Mode Dispersion, PMD) shadow
It rings seriously, so as to cause pulse broadening, causes serious intersymbol interference, moreover, when number of sub carrier wave is more, subcarrier
Greatest differences between frequency values can also deteriorate PDM-CO-OFDM system performance.In the prior art, in order to compensate for polarization effect pair
It is damaged caused by PDM-CO-OFDM system performance, it is general to be carried out using pilot signal transmitted or the method for being inserted into training sequence
Channel equalization, this method are clearly that the frequency spectrum benefit of system is significantly reduced using the sacrificial system availability of frequency spectrum as cost
With rate.
Summary of the invention
The embodiment of the invention provides a kind of approach for blind channel equalization and device, computer storage medium and equipment is calculated,
To solve the caused PDM-CO-OFDM system when carrying out channel equalization using pilot signal or training sequence in the prior art
The low problem of the availability of frequency spectrum of uniting.
Specific technical solution provided in an embodiment of the present invention is as follows:
A kind of approach for blind channel equalization is applied to PDM-CO-OFDM system, this method comprises:
It is pre-processed for ofdm signal is received, obtains N number of OFDM symbol, and corresponding for N number of OFDM symbol
Each subcarrier successively executes following operation, until getting the destination channel frequency response inverse matrix of each subcarrier:
Obtain the initial channel frequency response inverse matrix of subcarrier, wherein the initial channel of first subcarrier
Frequency response inverse matrix is that the frequency domain data based on first subcarrier in N number of OFDM symbol obtains,
The initial channel frequency response inverse matrix of each other subcarrier in addition to first subcarrier is previous
The destination channel frequency response inverse matrix of a subcarrier；
According to preset iteration optimization mode, optimization is iterated to initial channel frequency response inverse matrix, is obtained
Take the destination channel frequency response inverse matrix of subcarrier, wherein every execution an iteration optimization is based on this
When estimation error and the current iteration optimization of the optimization channel frequency response inverse matrix obtained after iteration optimization
Iteration step length, adjustment next iteration optimization when iteration step length；
Destination channel frequency response inverse matrix and frequency domain data based on each subcarrier restore transmitting terminal in corresponding subcarrier
The data of upper transmission.
Preferably, being pre-processed for ofdm signal is received, N number of OFDM symbol is obtained, comprising:
After carrying out sign synchronization, carrier frequency estimation and dispersion compensation processing to the ofdm signal received, it is changed into N through FFT
A OFDM symbol.
Preferably, after obtaining N number of OFDM symbol, further includes:
Carry out blind CPE compensation for N number of OFDM symbol, and to the compensated N number of OFDM symbol of blind CPE it is corresponding each
The frequency domain data of subcarrier takes mean value and albefaction.
Preferably, being iterated optimization according to preset iteration optimization mode to initial channel frequency response inverse matrix, obtaining son
The destination channel frequency response inverse matrix of carrier wave, comprising:
Optimization is iterated to initial channel frequency response inverse matrix using following formula, until meeting preset iteration ends item
Until part:
Wherein, k characterizes the number of iterations；The optimization channel frequency response for characterizing i-th of subcarrier after current iteration optimizes is inverse
Matrix；When first time iteration,Characterize the initial channel frequency response inverse matrix of i-th of subcarrier, non-first time iteration
When,The optimization channel frequency response inverse matrix of i-th of subcarrier after the last iteration optimization of characterization；It is excellent that μ characterizes iteration
Iteration step length when change；The optimization channel frequency response inverse matrix of i-th of subcarrier after the last iteration optimization of characterization
Minimum mutual information.
Preferably, every execution an iteration optimization, based on the optimization channel frequency response inverse matrix obtained after current iteration optimization
Estimation error and last iteration optimization when iteration step length, iteration step length when adjustment current iteration optimization, comprising:
Every execution an iteration optimization, iteration step length when using following formula adjustment current iteration optimization:
Wherein, k characterizes the number of iterations；μ (k) characterizes iteration step length when current iteration optimization；β characterizes forgetting factor；μ
(k-1) iteration step length when last iteration optimization is characterized；ρ characterizes scale factor；It is obtained after characterization current iteration optimization
Optimization channel frequency response inverse matrix estimation error.
Preferably, destination channel frequency response inverse matrix and frequency domain data based on each subcarrier, restore transmitting terminal in phase
Answer the data sent on subcarrier, comprising:
For each subcarrier, the data that transmitting terminal is sent on corresponding subcarrier are restored using following formula:
Wherein,The p-polarization data that characterization transmitting terminal is sent on i-th of subcarrier；
Receiving end is characterized in the q polarization data of i-th of received over subcarriers；The destination channel frequency response for characterizing i-th of subcarrier is inverse
Matrix.
A kind of algorithm for blind channel equalization device, for carrying out algorithm for blind channel equalization, algorithm for blind channel equalization dress to PDM-CO-OFDM system
It sets and includes:
Preprocessing module obtains N number of OFDM symbol for being pre-processed for receiving ofdm signal；
Optimization module, for successively executing following operation for each corresponding subcarrier of N number of OFDM symbol, until obtaining
Until the destination channel frequency response inverse matrix for getting each subcarrier:
Obtain the initial channel frequency response inverse matrix of subcarrier, wherein the initial channel frequency response matrix of first subcarrier is
What the frequency domain data based on first subcarrier in N number of OFDM symbol obtained, in addition to first subcarrier it is other each
The initial channel frequency response inverse matrix of subcarrier is the destination channel frequency response inverse matrix of previous subcarrier；
According to preset iteration optimization mode, optimization is iterated to initial channel frequency response inverse matrix, obtains subcarrier
Destination channel frequency response inverse matrix, wherein every execution an iteration optimization, based on the optimization channel frequency obtained after current iteration optimization
The iteration step length when estimation error and current iteration for ringing inverse matrix optimize, iteration step when adjustment next iteration optimizes
It is long；
Recovery module is restored to send for destination channel frequency response inverse matrix and frequency domain data based on each subcarrier
Hold the data sent on corresponding subcarrier.
Preferably, being pre-processed for ofdm signal is received, when obtaining N number of OFDM symbol, preprocessing module is specific
For:
After carrying out sign synchronization, carrier frequency estimation and dispersion compensation processing to the ofdm signal received, it is changed into N through FFT
A OFDM symbol.
Preferably, preprocessing module is also used to after obtaining N number of OFDM symbol:
Carry out blind CPE compensation for N number of OFDM symbol, and to the compensated N number of OFDM symbol of blind CPE it is corresponding each
The frequency domain data of subcarrier takes mean value and albefaction.
Preferably, being iterated optimization according to preset iteration optimization mode to initial channel frequency response inverse matrix, obtaining son
When the destination channel frequency response inverse matrix of carrier wave, optimization module is specifically used for:
Optimization is iterated to initial channel frequency response inverse matrix using following formula, until meeting preset iteration ends item
Until part:
Wherein, k characterizes the number of iterations；The optimization channel frequency response for characterizing i-th of subcarrier after current iteration optimizes is inverse
Matrix；When first time iteration,Characterize the initial channel frequency response inverse matrix of i-th of subcarrier, non-first time iteration
When,The optimization channel frequency response inverse matrix of i-th of subcarrier after the last iteration optimization of characterization；It is excellent that μ characterizes iteration
Iteration step length when change；The optimization channel frequency response inverse matrix of i-th of subcarrier after the last iteration optimization of characterization
Minimum mutual information.
Preferably, every execution an iteration optimization, based on the optimization channel frequency response inverse matrix obtained after current iteration optimization
Estimation error and last iteration optimization when iteration step length, when iteration step length when adjustment current iteration optimization, optimization
Module is specifically used for:
Every execution an iteration optimization, iteration step length when using following formula adjustment current iteration optimization:
Wherein, k characterizes the number of iterations；μ (k) characterizes iteration step length when current iteration optimization；β characterizes forgetting factor；μ
(k-1) iteration step length when last iteration optimization is characterized；ρ characterizes scale factor；It is obtained after characterization current iteration optimization
Optimization channel frequency response inverse matrix estimation error.
Preferably, destination channel frequency response inverse matrix and frequency domain data based on each subcarrier, restore transmitting terminal in phase
When answering the data sent on subcarrier, recovery module is specifically used for:
For each subcarrier, the data that transmitting terminal is sent on corresponding subcarrier are restored using following formula:
Wherein,The p-polarization data that characterization transmitting terminal is sent on i-th of subcarrier；
Receiving end is characterized in the q polarization data of i-th of received over subcarriers；The destination channel frequency response for characterizing i-th of subcarrier is inverse
Matrix.
A kind of nonvolatile computer storage media, computer storage medium are stored with executable program, executable program
It is executed by processor the step of realizing above-mentioned approach for blind channel equalization.
A kind of calculating equipment, including memory, processor, and the computer program of storage on a memory, processor
The step of realizing above-mentioned approach for blind channel equalization when executing computer program.
The embodiment of the present invention has the beneficial effect that:
In the embodiment of the present invention, destination channel frequency response inverse matrix is being obtained, and restore using destination channel frequency response inverse matrix
Transmitting terminal, without using pilot signal or training sequence, saves slotting during the data sent on each subcarrier
The expense for entering pilot signal or training sequence effectively improves the availability of frequency spectrum of PDM-CO-OFDM system, moreover,
During the destination channel frequency response inverse matrix for obtaining each subcarrier, when adaptively adjusting iteration optimization using estimation error
Iteration step length, accelerate the convergence rate of iteration optimization as much as possible, improve the efficiency of algorithm for blind channel equalization.
Detailed description of the invention
Fig. 1 is the overview schematic diagram of approach for blind channel equalization in the embodiment of the present invention one；
Fig. 2 is the idiographic flow schematic diagram of approach for blind channel equalization in the embodiment of the present invention two；
Fig. 3 is the illustrative view of functional configuration of algorithm for blind channel equalization device in the embodiment of the present invention three.
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, is not whole 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.
In order to solve the caused PDM- when carrying out channel equalization using pilot signal or training sequence in the prior art
The low problem of CO-OFDM system spectrum utilization rate, it is equal as blind Channel using the independence between each subcarrier in the embodiment of the present invention
Weighing apparatus basis is carrying out the pretreatments such as sign synchronization, carrier frequency estimation and dispersion compensation processing for the ofdm signal received, is obtaining
To after N number of OFDM symbol, common phase noise error (Common Phase Error, CPE) is carried out for N number of OFDM symbol and is mended
It repays, and mean value and albefaction is taken to the frequency domain data of each corresponding subcarrier of the compensated N number of OFDM symbol of CPE, later, according to
It is secondary obtain each subcarrier destination channel frequency response inverse matrix, using each subcarrier destination channel frequency response inverse matrix and
Frequency domain data restores the data that transmitting terminal is sent on corresponding subcarrier, and in the destination channel frequency for obtaining each subcarrier
During ringing inverse matrix, iteration step length when iteration optimization is adaptively adjusted using estimation error, is accelerated as much as possible repeatedly
The convergence rate of generation optimization, improves the efficiency of algorithm for blind channel equalization, moreover, obtaining destination channel frequency response inverse matrix and utilizing mesh
Mark channel frequency response inverse matrix and restore transmitting terminal during the data sent on each subcarrier, without using pilot signal or
Person's training sequence saves the expense of insertion pilot signal or training sequence, effectively improves PDM-CO-OFDM system
The availability of frequency spectrum.
The present invention program is described in detail below by specific embodiment, certainly, the present invention is not limited to following realities
Apply example.
Embodiment one
In practical applications, PDM-CO-OFDM system only consider linear damage in the case where, single sub-carrier
Frequency domain data can use but be not limited to as shown in formula (1) 2 × 2 multiple-input and multiple-output (Multiple-Input
Multiple-Output, MIMO) OFDM model describes:
Wherein,Receiving end is characterized in the q polarization data of i-th of received over subcarriers；
The p-polarization data that characterization transmitting terminal is sent on i-th of subcarrier；Characterize the channel frequency response matrix of i-th of subcarrier.
In PDM-CO-OFDM system, within an OFDM symbol period, fiber channel changes with time very slow
Slowly, channel frequency response hardly changes with time variation, at this point, the data that transmitting terminal is sent on i-th of subcarrier
Restore are as follows:
Wherein,Receiving end is characterized in the q polarization data of i-th of received over subcarriers；
The p-polarization data that characterization transmitting terminal is sent on i-th of subcarrier；Characterize the channel frequency response inverse matrix of i-th of subcarrier.
Based on this, in the embodiment of the present invention one, a kind of approach for blind channel equalization is provided, as shown in fig.1, the blind Channel
The process of equalization methods is as follows:
Step 100: being pre-processed for ofdm signal is received, obtain N number of OFDM symbol, and accord with for N number of OFDM
Number each corresponding subcarrier successively executes step 101 to step 102, until getting the destination channel of each subcarrier
Until frequency response inverse matrix.
In the specific implementation, when executing step 100, it can use but be not limited to following manner:
Firstly, carrying out sign synchronization, carrier frequency estimation and dispersion after receiving ofdm signal to the ofdm signal received and mending
Processing is repaid, then is changed into N number of OFDM symbol through Fast Fourier Transform (FFT) (Fast Fourier Transformation, FFT).
Then, blind common phase error (Common Phase Error, CPE) is carried out for N number of OFDM symbol to compensate, and
The frequency domain data of each corresponding subcarrier of compensated to blind CPE N number of OFDM symbol takes mean value and albefaction.
Finally, successively executing step 101 to step 102, until obtaining for each corresponding subcarrier of N number of OFDM symbol
Until the destination channel frequency response inverse matrix for getting each subcarrier.
Step 101: obtaining the initial channel frequency response inverse matrix of subcarrier, wherein the initial channel frequency of first subcarrier
Ringing inverse matrix is that the frequency domain data based on first subcarrier in N number of OFDM symbol obtains, in addition to first subcarrier
The initial channel frequency response inverse matrix of each other subcarrier is the destination channel frequency response inverse matrix of previous subcarrier.
Step 102: according to preset iteration optimization mode, optimization being iterated to initial channel frequency response inverse matrix, is obtained
The destination channel frequency response inverse matrix of subcarrier, wherein every execution an iteration optimization, it is excellent based on being obtained after current iteration optimization
The iteration step length when estimation error and current iteration for changing channel frequency response inverse matrix optimize, when adjustment next iteration optimizes
Iteration step length.
In practical applications, the iteration step length of first time iteration optimization can be a preset fixed value, have
When body is implemented, it can use but be not limited to be iterated optimization to initial channel frequency response inverse matrix using formula (3), until meeting
Until preset stopping criterion for iteration, wherein preset stopping criterion for iteration can be but be not limited to: optimizing in current iteration
Difference between two optimization channel frequency response inverse matrixs of front and back is less than preset threshold:
Wherein, k characterizes the number of iterations；The optimization channel frequency response for characterizing i-th of subcarrier after current iteration optimizes is inverse
Matrix；When first time iteration,Characterize the initial channel frequency response inverse matrix of i-th of subcarrier, non-first time iteration
When,The optimization channel frequency response inverse matrix of i-th of subcarrier after the last iteration optimization of characterization；μ (k) characterizes this
Iteration step length when iteration optimization；The optimization channel frequency response of i-th of subcarrier after the last iteration optimization of characterization
The Minimum mutual information of inverse matrix.
Preferably, in above-mentioned formula (3)It can be obtained by formula (4) to formula (8):
It is tellable to be, optimization is being iterated to initial channel frequency response inverse matrix to formula (8) using above-mentioned formula (3)
During, iteration step length controls the convergence rate of iteration optimization, if iteration step length is larger, convergence rate can be very fast, but accidentally
Difference can become larger, conversely, convergence rate can be slack-off, and error is smaller if iteration step length becomes smaller.In practical applications, in order to
It is enough to accelerate the convergence rate of iteration optimization while guaranteeing that the error of iteration optimization does not increase, it can use estimation error certainly
Adapting to adjusting iteration step length specifically can use but be not limited to following manner: every execution an iteration optimization can use
But iteration step length when being not limited to using formula (9) adjustment current iteration optimization:
Wherein, k characterizes the number of iterations；μ (k) characterizes iteration step length when current iteration optimization；β characterization forgetting factor, one
As take real number close to 1, it is clear that β is bigger, and the adjustment amplitude of iteration step length is smaller；When μ (k-1) characterization last time iteration optimization
Iteration step length；ρ characterizes scale factor；The error of the optimization channel frequency response inverse matrix obtained after characterization current iteration optimization
Estimation.
Preferably, in above-mentioned formula (9)It can be obtained by formula (10):
Wherein,The smoothed version of characterization optimization channel frequency response inverse matrix, in the specific implementation, Ke Yiqu
Maximum absolute value element as final estimation error.
It is tellable to be, in order to avoid due to iteration step length it is excessive, cause the iteration to initial channel frequency response inverse matrix excellent
Change unstable, a upper limit can be preset for iteration step length, specifically, can use but be not limited to limit using formula (11)
Determine the upper limit of iteration step length:
Step 103: destination channel frequency response inverse matrix and frequency domain data based on each subcarrier restore transmitting terminal in phase
Answer the data sent on subcarrier.In the specific implementation, it can use but be not limited to above-mentioned formula (1) and restore transmitting terminal corresponding
The data sent on subcarrier.
Further, in the destination channel frequency response inverse matrix and frequency domain data using each subcarrier to PDM-CO-
Ofdm system is carried out channel equalization and may be used also after being damaged caused by the performance of PDM-CO-OFDM system with compensating polarizing effect
To carry out inter-carrier interference (Inter-Carrier Interference, ICI), specifically, can use in the prior art
Mode carries out ICI compensation, and details are not described herein.
As it can be seen that obtaining destination channel frequency response inverse matrix in the embodiment of the present invention one and utilizing destination channel frequency response against square
Battle array restores transmitting terminal during the data sent on each subcarrier, without using pilot signal or training sequence, section
The expense for having saved insertion pilot signal or training sequence, effectively improves the availability of frequency spectrum of PDM-CO-OFDM system, and
And during obtaining the destination channel frequency response inverse matrix of each subcarrier, iteration is adaptively adjusted using estimation error
Iteration step length when optimization accelerates the convergence rate of iteration optimization as much as possible, improves the efficiency of algorithm for blind channel equalization.
Embodiment two
It is described in further detail below for above-described embodiment, as shown in fig.2, in the embodiment of the present invention two, fanaticism
The detailed process of trace equalization method is as follows:
Step 200: after receiving ofdm signal, sign synchronization, carrier frequency estimation and color being carried out to the ofdm signal received
Compensation deals are dissipated, then are changed into N number of OFDM symbol through FFT.
Step 201: carrying out blind CPE compensation for N number of OFDM symbol, and corresponding to the compensated N number of OFDM symbol of blind CPE
The frequency domain data of each subcarrier take mean value and albefaction.
Step 202: successively executing step 203 to step 207, directly for each corresponding subcarrier of N number of OFDM symbol
Until the destination channel frequency response inverse matrix for getting each subcarrier.
Step 203: obtaining the initial channel frequency response inverse matrix of subcarrier.Wherein, the initial channel frequency of first subcarrier
Ringing inverse matrix is that the frequency domain data based on first subcarrier in N number of OFDM symbol obtains, in addition to first subcarrier
The initial channel frequency response inverse matrix of each other subcarrier is the destination channel frequency response inverse matrix of previous subcarrier.
Step 204: through the embodiment of the present invention the formula (3) in one to formula (8) to initial channel frequency response inverse matrix into
Row iteration optimization obtains optimization channel frequency response inverse matrix.
Step 205: judging that the difference between two optimization channel frequency response inverse matrixs before and after current iteration optimizes is less than
(wherein, which can be set to 10 to preset threshold-4), that is, judge whether to meet preset stopping criterion for iteration, if so,
Then follow the steps 207；Otherwise, step 206 is executed.
Step 206: when the formula (3) in one to formula (8) adjusts next iteration optimization through the embodiment of the present invention
Iteration step length, and return step 204 optimize into next iteration.
Step 207: the optimization channel frequency response inverse matrix obtained after current iteration is optimized is believed as the target of the subcarrier
Road frequency response inverse matrix.
Step 208: after getting the destination channel frequency response inverse matrix of each subcarrier, through the embodiment of the present invention in one
Formula (2), restore the data that send on each subcarrier of transmitting terminal, and carry out ICI compensation for the data after restoring.
Embodiment three
Based on the above embodiment, the embodiment of the present invention three provides a kind of algorithm for blind channel equalization device, for PDM-CO-
Ofdm system carries out algorithm for blind channel equalization, as shown in fig.3, the algorithm for blind channel equalization device includes at least:
Preprocessing module 300 obtains N number of OFDM symbol for being pre-processed for receiving ofdm signal；
Optimization module 301, for successively executing following operation for each corresponding subcarrier of N number of OFDM symbol, directly
Until the destination channel frequency response inverse matrix for getting each subcarrier:
Obtain the initial channel frequency response inverse matrix of subcarrier, wherein the initial channel frequency response matrix of first subcarrier is
What the frequency domain data based on first subcarrier in N number of OFDM symbol obtained, in addition to first subcarrier it is other each
The initial channel frequency response inverse matrix of subcarrier is the destination channel frequency response inverse matrix of previous subcarrier；
According to preset iteration optimization mode, optimization is iterated to initial channel frequency response inverse matrix, obtains subcarrier
Destination channel frequency response inverse matrix, wherein every execution an iteration optimization, based on the optimization channel frequency obtained after current iteration optimization
The iteration step length when estimation error and current iteration for ringing inverse matrix optimize, iteration step when adjustment next iteration optimizes
It is long；
Recovery module 302 restores hair for destination channel frequency response inverse matrix and frequency domain data based on each subcarrier
The data that sending end is sent on corresponding subcarrier.
Preferably, being pre-processed for ofdm signal is received, when obtaining N number of OFDM symbol, preprocessing module 300 has
Body is used for:
After carrying out sign synchronization, carrier frequency estimation and dispersion compensation processing to the ofdm signal received, it is changed into N through FFT
A OFDM symbol.
Preferably, preprocessing module 300 is also used to after obtaining N number of OFDM symbol:
CPE compensation is carried out for N number of OFDM symbol, and the corresponding each height of the compensated N number of OFDM symbol of CPE is carried
The frequency domain data of wave takes mean value and carries out albefaction.
Preferably, being iterated optimization according to preset iteration optimization mode to initial channel frequency response inverse matrix, obtaining son
When the destination channel frequency response inverse matrix of carrier wave, optimization module 301 is specifically used for:
Optimization is iterated to initial channel frequency response inverse matrix using following formula, until meeting preset iteration ends item
Until part:
Wherein, k characterizes the number of iterations；The optimization channel frequency response for characterizing i-th of subcarrier after current iteration optimizes is inverse
Matrix；When first time iteration,Characterize the initial channel frequency response inverse matrix of i-th of subcarrier, non-first time iteration
When,The optimization channel frequency response inverse matrix of i-th of subcarrier after the last iteration optimization of characterization；It is excellent that μ characterizes iteration
Iteration step length when change；The optimization channel frequency response inverse matrix of i-th of subcarrier after the last iteration optimization of characterization
Minimum mutual information.
Preferably, every execution an iteration optimization, based on the optimization channel frequency response inverse matrix obtained after current iteration optimization
Estimation error and last iteration optimization when iteration step length, when iteration step length when adjustment current iteration optimization, optimization
Module 301 is specifically used for:
Every execution an iteration optimization, iteration step length when using following formula adjustment current iteration optimization:
Wherein, k characterizes the number of iterations；μ (k) characterizes iteration step length when current iteration optimization；β characterizes forgetting factor；μ
(k-1) iteration step length when last iteration optimization is characterized；ρ characterizes scale factor；It is obtained after characterization current iteration optimization
Optimization channel frequency response inverse matrix estimation error.
Preferably, destination channel frequency response inverse matrix and frequency domain data based on each subcarrier, restore transmitting terminal in phase
When answering the data sent on subcarrier, recovery module 302 is specifically used for:
For each subcarrier, the data that transmitting terminal is sent on corresponding subcarrier are restored using following formula:
Wherein,The p-polarization data that characterization transmitting terminal is sent on i-th of subcarrier；
Receiving end is characterized in the q polarization data of i-th of received over subcarriers；The destination channel frequency response for characterizing i-th of subcarrier is inverse
Matrix.
Example IV
A kind of nonvolatile computer storage media, computer storage medium are stored with executable program, executable program
It is executed by processor the step of realizing above-mentioned approach for blind channel equalization.
Embodiment five
A kind of calculating equipment, including memory, processor, and the computer program of storage on a memory, processor
The step of realizing above-mentioned approach for blind channel equalization when executing computer program.
In conclusion being pre-processed in the embodiment of the present invention for ofdm signal is received, N number of OFDM symbol is obtained,
And following operation is successively executed for each corresponding subcarrier of N number of OFDM symbol, until getting each subcarrier
Until destination channel frequency response inverse matrix: obtaining the initial channel frequency response inverse matrix of subcarrier, wherein first subcarrier it is initial
Channel frequency response matrix is that the frequency domain data based on first subcarrier in N number of OFDM symbol obtains, except first subcarrier it
The initial channel frequency response inverse matrix of each outer other subcarrier is the destination channel frequency response inverse matrix of previous subcarrier；It presses
According to preset iteration optimization mode, optimization is iterated to initial channel frequency response inverse matrix, obtains the destination channel frequency of subcarrier
Ring inverse matrix, wherein every execution an iteration optimization, based on the optimization channel frequency response inverse matrix obtained after current iteration optimization
Iteration step length when estimation error and current iteration optimize, iteration step length when adjustment next iteration optimizes；Based on each
The destination channel frequency response inverse matrix and frequency domain data of a subcarrier restore the data that transmitting terminal is sent on corresponding subcarrier.It should
Method is obtaining destination channel frequency response inverse matrix and is restoring transmitting terminal on each subcarrier using destination channel frequency response inverse matrix
During the data of transmission, without using pilot signal, perhaps training sequence saves insertion pilot signal or training sequence
The expense of column effectively improves the availability of frequency spectrum of PDM-CO-OFDM system, moreover, in the mesh for obtaining each subcarrier
During marking channel frequency response inverse matrix, iteration step length when iteration optimization is adaptively adjusted using estimation error, as much as possible
The convergence rate for accelerating iteration optimization improves the efficiency of algorithm for blind channel equalization.
It should be understood by those skilled in the art that, the embodiment of the present invention can provide as method, system or computer program
Product.Therefore, complete hardware embodiment, complete software embodiment or reality combining software and hardware aspects can be used in the present invention
Apply the form of example.Moreover, it wherein includes the computer of computer usable program code that the present invention, which can be used in one or more,
The computer program implemented in usable storage medium (including but not limited to magnetic disk storage, CD-ROM, optical memory etc.) produces
The form of product.
The present invention be referring to according to the method for the embodiment of the present invention, the process of equipment (system) and computer program product
Figure and/or block diagram describe.It should be understood that every one stream in flowchart and/or the block diagram can be realized by computer program instructions
The combination of process and/or box in journey and/or box and flowchart and/or the block diagram.It can provide these computer programs
Instruct the processor of general purpose computer, special purpose computer, Embedded Processor or other programmable data processing devices to produce
A raw machine, so that being generated by the instruction that computer or the processor of other programmable data processing devices execute for real
The device for the function of being specified in present one or more flows of the flowchart and/or one or more blocks of the block diagram.
These computer program instructions, which may also be stored in, is able to guide computer or other programmable data processing devices with spy
Determine in the computer-readable memory that mode works, so that it includes referring to that instruction stored in the computer readable memory, which generates,
Enable the manufacture of device, the command device realize in one box of one or more flows of the flowchart and/or block diagram or
The function of being specified in multiple boxes.
These computer program instructions also can be loaded onto a computer or other programmable data processing device, so that counting
Series of operation steps are executed on calculation machine or other programmable devices to generate computer implemented processing, thus in computer or
The instruction executed on other programmable devices is provided for realizing in one or more flows of the flowchart and/or block diagram one
The step of function of being specified in a box or multiple boxes.
Although preferred embodiments of the present invention have been described, it is created once a person skilled in the art knows basic
Property concept, then additional changes and modifications may be made to these embodiments.So it includes excellent that the following claims are intended to be interpreted as
It selects embodiment and falls into all change and modification of the scope of the invention.
Obviously, those skilled in the art can carry out various modification and variations without departing from this hair to the embodiment of the present invention
The spirit and scope of bright embodiment.In this way, if these modifications and variations of the embodiment of the present invention belong to the claims in the present invention
And its within the scope of equivalent technologies, then the present invention is also intended to include these modifications and variations.
Claims (9)
1. a kind of approach for blind channel equalization, which is characterized in that be applied to palarization multiplexing coherent light orthogonal frequency division multiplexing PDM-CO-
Ofdm system, which comprises
It is pre-processed for ofdm signal is received, obtains N number of OFDM symbol, and corresponding for N number of OFDM symbol
Each subcarrier successively executes following operation, until getting the destination channel frequency response inverse matrix of each subcarrier:
Obtain the initial channel frequency response inverse matrix of subcarrier, wherein the initial channel frequency response matrix of first subcarrier is based on N
The frequency domain data of first subcarrier obtains in a OFDM symbol, other each in addition to first subcarrier
The initial channel frequency response inverse matrix of a subcarrier is the destination channel frequency response inverse matrix of previous subcarrier；
According to preset iteration optimization mode, optimization is iterated to the initial channel frequency response inverse matrix, obtains the sub- load
The destination channel frequency response inverse matrix of wave, wherein every execution an iteration optimization, based on the optimization letter obtained after current iteration optimization
Iteration step length when estimation error and the current iteration optimization of road frequency response inverse matrix, iteration when adjustment next iteration optimizes
Step-length；
Destination channel frequency response inverse matrix and frequency domain data based on each subcarrier are restored transmitting terminal and are sent out on corresponding subcarrier
The data sent.
2. approach for blind channel equalization as described in claim 1, which is characterized in that located in advance for ofdm signal is received
Reason, obtains N number of OFDM symbol, comprising:
It is fast fourier transformed after carrying out sign synchronization, carrier frequency estimation and dispersion compensation processing to the ofdm signal received
FFT is changed into N number of OFDM symbol.
3. approach for blind channel equalization as described in claim 1, which is characterized in that after obtaining N number of OFDM symbol, further includes:
Blind common phase noise error CPE compensation is carried out for N number of OFDM symbol, and to the compensated N number of OFDM of blind CPE
The frequency domain data of each corresponding subcarrier of symbol takes mean value and albefaction.
4. approach for blind channel equalization as described in claim 1, which is characterized in that according to preset iteration optimization mode, to institute
It states initial channel frequency response inverse matrix and is iterated optimization, obtain the destination channel frequency response inverse matrix of the subcarrier, comprising:
Optimization is iterated to the initial channel frequency response inverse matrix using following formula, until meeting preset iteration ends item
Until part:
Wherein, k characterizes the number of iterations；The optimization channel frequency response of i-th of subcarrier after current iteration optimization is characterized against square
Battle array；When first time iteration,Characterize the initial channel frequency response inverse matrix of i-th of subcarrier, when non-first time iteration,The optimization channel frequency response inverse matrix of i-th of subcarrier after the last iteration optimization of characterization；When μ characterizes iteration optimization
Iteration step length；Characterize the optimization channel frequency response inverse matrix of i-th of subcarrier after last iteration optimization most
Small mutual information.
5. approach for blind channel equalization as claimed in claim 4, which is characterized in that every execution an iteration optimization is based on this
The iteration step length when estimation error of the optimization channel frequency response inverse matrix obtained after iteration optimization and last iteration optimization, is adjusted
Iteration step length when whole current iteration optimizes, comprising:
Every execution an iteration optimization, iteration step length when using following formula adjustment current iteration optimization:
Wherein, k characterizes the number of iterations；μ (k) characterizes iteration step length when current iteration optimization；β characterizes forgetting factor；μ(k-1)
Characterize iteration step length when last iteration optimization；ρ characterizes scale factor；It is obtained after characterization current iteration optimization excellent
Change the estimation error of channel frequency response inverse matrix.
6. approach for blind channel equalization as described in claim 1, which is characterized in that the destination channel frequency based on each subcarrier
Inverse matrix and frequency domain data are rung, the data that transmitting terminal is sent on corresponding subcarrier are restored, comprising:
For each subcarrier, the data that transmitting terminal is sent on corresponding subcarrier are restored using following formula:
Wherein,The p-polarization data that characterization transmitting terminal is sent on i-th of subcarrier；
Receiving end is characterized in the q polarization data of i-th of received over subcarriers；The destination channel frequency response for characterizing i-th of subcarrier is inverse
Matrix.
7. a kind of algorithm for blind channel equalization device, which is characterized in that for palarization multiplexing coherent light orthogonal frequency division multiplexing PDM-CO-
Ofdm system carries out algorithm for blind channel equalization, and the algorithm for blind channel equalization device includes:
Preprocessing module obtains N number of OFDM symbol for being pre-processed for receiving ofdm signal；
Optimization module, for successively executing following operation for each corresponding subcarrier of N number of OFDM symbol, until obtaining
Until the destination channel frequency response inverse matrix for getting each subcarrier:
Obtain the initial channel frequency response inverse matrix of subcarrier, wherein the initial channel frequency response matrix of first subcarrier is based on N
The frequency domain data of first subcarrier obtains in a OFDM symbol, other each in addition to first subcarrier
The initial channel frequency response inverse matrix of a subcarrier is the destination channel frequency response inverse matrix of previous subcarrier；
According to preset iteration optimization mode, optimization is iterated to the initial channel frequency response inverse matrix, obtains the sub- load
The destination channel frequency response inverse matrix of wave, wherein every execution an iteration optimization, based on the optimization letter obtained after current iteration optimization
Iteration step length when estimation error and the current iteration optimization of road frequency response inverse matrix, iteration when adjustment next iteration optimizes
Step-length；
Recovery module restores transmitting terminal and exists for destination channel frequency response inverse matrix and frequency domain data based on each subcarrier
The data sent on corresponding subcarrier.
8. a kind of nonvolatile computer storage media, which is characterized in that the computer storage medium is stored with executable journey
Sequence, the executable code processor execute the step of realizing the approach for blind channel equalization as described in claim 1-6 is any.
9. a kind of calculating equipment, which is characterized in that including memory, processor, and the calculating being stored on the memory
Machine program, the processor realize the algorithm for blind channel equalization side as described in claim 1-6 is any when executing the computer program
The step of method.
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