CN106936513A - A kind of carrier phase recovery method and device based on Kalman filtering algorithm - Google Patents
A kind of carrier phase recovery method and device based on Kalman filtering algorithm Download PDFInfo
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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
- H04B10/612—Coherent receivers for optical signals modulated with a format different from binary or higher-order PSK [X-PSK], e.g. QAM, DPSK, FSK, MSK, ASK
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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
- H04B10/613—Coherent receivers including phase diversity, e.g., having in-phase and quadrature branches, as in QPSK coherent receivers
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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
- H04B10/6165—Estimation of the phase of the received optical signal, phase error estimation or phase error correction
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
- H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
- H04L27/36—Modulator circuits; Transmitter circuits
- H04L27/362—Modulation using more than one carrier, e.g. with quadrature carriers, separately amplitude modulated
Abstract
A kind of carrier phase recovery method and device based on Kalman filtering algorithm are the embodiment of the invention provides, methods described includes：Carrier phase estimation is carried out to 16QAM signals by carrier phase algorithm for estimating, first phase estimate is obtained；Phase recovery is carried out to the 16QAM signals according to the first phase estimate, the 16QAM signals after the first recovery are obtained；Phase estimation is carried out to the 16QAM signals after the recovery by Kalman filtering algorithm, second phase estimate is obtained；Phase recovery is carried out to the 16QAM signals after the recovery according to second estimate, the 16QAM signals after the second recovery are obtained.Using the embodiment of the present invention, the error of phase estimation in Kalman filtering algorithm, the influence of more accurate removal phase noise and amplitude noise are effectively reduced.
Description
Technical field
The present invention relates to the communications field, more particularly to a kind of carrier phase recovery method based on Kalman filtering algorithm
And device.
Background technology
In recent years, high-speed AD converter (Analog-to-Digital Converter, ADC) technology, integrated optical device
And Digital Signal Processing (Digital Signal Processing, DSP) technology, promote optical communication field to be based on relevant
The fast development of the coherent light communication technology of detection.Wherein, 16QAM (Quadrature Amplitude Modulation,
Quadrature amplitude modulation) coherent transmission system in, phase noise and amplitude noise are that limitation high-speed high capacity digital coherent light leads to
Believe a principal element of systematic function.Phase noise is mainly by laser linewidth, and ASE (Amplified
Spontaneous Emission, Amplified Spontaneous Emission) nonlinear interaction between noise and signal causes；Amplitude is made an uproar
The main source of sound is ASE noises.Fig. 1 represents the primary signal figure of 16QAM signal constellation (in digital modulation) figures, and Fig. 2 is represented by phase noise shadow
Loud 16QAM signal constellation (in digital modulation) figures, Fig. 3 represents the 16QAM signal constellation (in digital modulation) figures influenceed by phase noise and amplitude noise.By Fig. 1, figure
2nd, Fig. 3 can be seen that phase noise can cause noise signal planisphere to rotate, and amplitude noise can cause the inclined of signal code
Move, if so can simultaneously remove phase noise and amplitude noise, the performance of system can be greatly improved.So remove phase
The key of position noise and amplitude noise is that carrier phase is estimated, only carries out phase estimation by these signals, could be judged
Whether signal is influenceed by these noises, if the estimate of phase estimation is different from the phase value of primary signal, illustrates this
Signal is influenceed by noise, then only need to carry out phase recovery according to estimate can just eliminate these noises.
In existing carrier phase estimation method, EKF (Extended Kalman Filter, Kalman filtering) algorithm
It can be the optimal estimation algorithm of the phase noise and amplitude noise that remove 16QAM signals simultaneously.The load of Kalman filtering algorithm
Wave phase method of estimation is broadly divided into time renewal and measurement updaue two parts, and the time updates mainly one priori of generation and estimates
Meter, then this prior estimate is improved in measurement updaue process according to the error with actual measured value, obtains Posterior estimator,
Namely final estimate.Specifically, first according to the Space admittance and the carrier wave of previous moment of Kalman filtering algorithm
Phase estimation value, obtains the prior estimate of the carrier phase error at the current time, and here, Space admittance is used for illustrating
The model of the variable to be estimated, including current time carrier phase phase noise actual value.Current time load is obtained again
The measured value of wave phase, and the error of prior estimate and measured value is calculated, obtain the predicated error of prior estimate and measured value；Most
Afterwards, the error covariance of the Carrier Phase Noise prior estimate at current time is updated according to predicated error, current time is obtained
The Posterior estimator of carrier phase error.
But existing Kalman filtering algorithm depends on previous moment to the decision error of current time phase estimation
The feedback that carrier phase is estimated, because the carrier phase of previous moment is estimated to be influenceed by larger noise phase, phase estimation value
It is inaccurate, cause current time phase estimation to produce larger evaluated error.
The content of the invention
In view of this, the purpose of the embodiment of the present invention is that a kind of carrier phase based on Kalman filtering algorithm of offer is extensive
Multiple method and device, effectively reduces the error of phase estimation in Kalman filtering algorithm, more accurate removal phase noise and width
Spend the influence of noise.Concrete technical scheme is as follows：
The embodiment of the invention discloses a kind of carrier phase recovery method based on Kalman filtering algorithm, it is applied to 16 and enters
Quadrature amplitude modulation 16QAM coherent transmission systems processed, methods described includes：
Carrier phase estimation is carried out to 16QAM signals by carrier phase algorithm for estimating, first phase estimate is obtained；
Phase recovery is carried out to the 16QAM signals according to the first phase estimate, after obtaining the first recovery
16QAM signals；
Phase estimation is carried out to the 16QAM signals after the recovery by Kalman filtering algorithm, second phase is obtained and is estimated
Evaluation；
Phase recovery is carried out to the 16QAM signals after the recovery according to second estimate, after obtaining the second recovery
16QAM signals.
Optionally, it is described that carrier phase estimation is carried out to 16QAM signals by carrier phase algorithm for estimating, including：
It is described that carrier phase estimation is carried out to the 16QAM signals by VV carrier phases algorithm for estimating.
Optionally, it is described that carrier phase estimation is carried out to the 16QAM signals by VV carrier phases algorithm for estimating, bag
Include：
The 16QAM signals are carried out into QPSK segmentation, the carrier phase of the 16QAM signals is obtained, it is described
Carrier phase at least includes phase modulation information, phase noise and noise phase；
The phase modulation information is removed by biquadratic computing, is obtained comprising the phase noise and the noise phase
The carrier phase；
The noise phase is eliminated according to average calculating operation, the estimate of the phase noise of the carrier phase is obtained,
The estimate of the phase noise is the first phase estimate.
Optionally, it is described that the 16QAM signals are carried out into QPSK segmentation, including：
Obtain the 16QAM signals corresponding constellation point on planisphere；
The QPSK segmentation is carried out to the constellation point, the corresponding subregion of the constellation point is obtained；
The subregion is adjudicated by amplitude, obtains meeting the phase signal of the QPSK, and by four phase
The phase signal of phase-shift keying (PSK) as the 16QAM signals carrier phase.
Optionally, it is described that phase estimation is carried out to the 16QAM signals after the recovery by Kalman filtering algorithm, bag
Include：
The Carrier Phase Noise estimate of the previous moment at current time is obtained, according to the sky of the Kalman filtering algorithm
Between state model and the previous moment Carrier Phase Noise estimate, the Carrier Phase Noise for obtaining the current time estimates
The prior estimate of meter and prior estimate error, the Space admittance include that the phase of the carrier phase at the current time is made an uproar
The actual value of sound；
Carrier phase prior estimate error according to the current time, obtains the Carrier Phase Noise at the current time
The error covariance of prior estimate；
The measured value of the Carrier Phase Noise at the current time is obtained, the Carrier Phase Noise at the current time is calculated
The prior estimate of estimation and the error of the measured value, obtain the prior estimate that the Carrier Phase Noise at the current time is estimated
With the predicated error of the measured value；
According to the predicated error, the prior estimate that the Carrier Phase Noise at the current time is estimated is updated, and it is described
The error covariance of the Carrier Phase Noise prior estimate at current time, after obtaining the Carrier Phase Noise at the current time
Test estimation, and the current time Carrier Phase Noise Posterior estimator error covariance.
Optionally, it is described that phase recovery is carried out to the 16QAM signals after the recovery according to second estimate, bag
Include：
Enter line phase to the 16QAM signals after the recovery according to second estimate to untwist, after obtaining the second recovery
16QAM signals.
The embodiment of the invention discloses a kind of carrier phase recovery device based on Kalman filtering algorithm, it is applied to
16QAM coherent transmission systems, described device includes：
First phase estimation module, for carrying out carrier phase estimation to 16QAM signals by carrier phase algorithm for estimating,
Obtain first phase estimate；
First phase recovery module, it is extensive for entering line phase to the 16QAM signals according to the first phase estimate
It is multiple, obtain the 16QAM signals after the first recovery；
Second phase estimation module, for carrying out phase to the 16QAM signals after the recovery by Kalman filtering algorithm
Position estimation, obtains second phase estimate；
Second phase recovery module, for carrying out phase to the 16QAM signals after the recovery according to second estimate
Bit recovery, obtains the 16QAM signals after the second recovery.
Optionally, the first phase estimation module, including：
First phase estimates submodule, for carrying out carrier phase to 16QAM signals by VV carrier phases algorithm for estimating
Estimate.
Optionally, the first phase estimates submodule, including：
Cutting unit, for the 16QAM signals to be carried out into QPSK segmentation, obtains the 16QAM signals
Carrier phase, the carrier phase at least includes phase modulation information, phase noise and noise phase；
Removal unit, for removing the phase modulation information by biquadratic computing, obtains comprising the phase noise
With the carrier phase of the noise phase；
Estimation unit, for eliminating the noise phase according to average calculating operation, obtains the phase of the carrier phase
The estimate of noise, the estimate of the phase noise is the first phase estimate.
Optionally, the cutting unit, specifically for：
Obtain the 16QAM signals corresponding constellation point on planisphere；
The QPSK segmentation is carried out to the constellation point, the corresponding subregion of the constellation point is obtained；
The subregion is adjudicated by amplitude, obtains meeting the phase signal of the QPSK, and by four phase
The phase signal of phase-shift keying (PSK) as the 16QAM signals carrier phase.
A kind of carrier phase recovery method and device based on Kalman filtering algorithm provided in an embodiment of the present invention, first lead to
Cross carrier phase algorithm for estimating carries out carrier phase estimation to 16QAM signals, the estimate of carrier phase is obtained, then according to load
The estimate of wave phase is recovered to carrier phase, eliminates the most of phase noise in 16QAM signals, reduces phase and estimates
The error of meter, then by Kalman filtering algorithm, the phase after recovery is estimated and recovered, so as to eliminate 16QAM signals
Middle remaining phase noise and amplitude noise.So, the major part during carrier phase algorithm for estimating eliminates 16QAM signals is first passed through
Phase noise, reduces the error of phase estimation, then by Kalman filtering algorithm to remaining phase noise and amplitude noise
Eliminated.Certainly, implementing any product of the invention or method must be not necessarily required to while reaching all the above excellent
Point.
Brief description of the drawings
In order to illustrate more clearly about the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing
The accompanying drawing to be used needed for having technology description is briefly described, it should be apparent that, drawings in the following description are only this
Some embodiments of invention, for those of ordinary skill in the art, on the premise of not paying creative work, can be with
Other accompanying drawings are obtained according to these accompanying drawings.
Fig. 1 is the primary signal figure of 16QAM signal constellation (in digital modulation)s figure provided in an embodiment of the present invention；
Fig. 2 is the 16QAM signal constellation (in digital modulation) figures by effect of phase noise provided in an embodiment of the present invention；
Fig. 3 is the 16QAM signal constellation (in digital modulation) figures influenceed by phase noise and amplitude noise provided in an embodiment of the present invention；
Fig. 4 is 16QAM coherent receivers Digital Signal Processing flow chart provided in an embodiment of the present invention；
Fig. 5 is a kind of the basic of carrier phase recovery method based on Kalman filtering algorithm provided in an embodiment of the present invention
Flow chart；
Fig. 6 is a kind of QPSK piecemeal schematic diagrames of 16QAM signals provided in an embodiment of the present invention；
Fig. 7 is a kind of fundamental block diagram of VV carrier phases algorithm for estimating provided in an embodiment of the present invention；
Fig. 8 is a kind of fundamental block diagram of Kalman filtering algorithm provided in an embodiment of the present invention；
Fig. 9 is a kind of model polar plot that carrier phase provided in an embodiment of the present invention estimates input signal；
Figure 10 is another model polar plot that carrier phase provided in an embodiment of the present invention estimates input signal；
Figure 11 is a kind of knot of carrier phase recovery device based on Kalman filtering algorithm provided in an embodiment of the present invention
Structure schematic diagram.
Specific embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete
Site preparation is described, it is clear that described embodiment is only a part of embodiment of the invention, rather than whole embodiments.It is based on
Embodiment in the present invention, it is every other that those of ordinary skill in the art are obtained under the premise of creative work is not made
Embodiment, belongs to the scope of protection of the invention.
At present, carrier phase algorithm for estimating is mainly used in coherent receiver, and digital baseband signal is processed.Figure
4 show 16QAM coherent receiver Digital Signal Processing flow charts, according to the function classification realized, are concerned with detection optic communication
The module of Digital Signal Processing is generally comprised：Front end correction, dispersion compensation and/or nonlinear compensation, Clock Extraction and recovery, partially
Polarization mode dispersion compensation and polarization demultiplexing, Frequency offset estimation, carrier phase estimation and hard/soft-decision etc..R in Fig. 4x(n)
Represent the input signal in X polarization states, ryN () represents the input signal in Y polarization states.From fig. 4, it can be seen that carrier phase estimate by
The Main Means of carrier phase recovery are gradually solved the problems, such as in light-receiving as realizing being concerned with recent years.The present invention is assuming that receiver
Linear damage and frequency deviation compensation are had been completed, only considers that laser phase noise and the spontaneous radiation amplification of link accumulation are made an uproar
In the case of the influence of sound (ASE), it is proposed that a kind of carrier phase recovery method and device based on Kalman filtering algorithm.
Referring to Fig. 5, Fig. 5 is a kind of carrier phase recovery side based on Kalman filtering algorithm provided in an embodiment of the present invention
The basic flow sheet of method, comprises the following steps：
S501, carrier phase estimation is carried out by carrier phase algorithm for estimating to 16QAM signals, obtains first phase estimation
Value.
Specifically, the M-ary digital modulation mode that QAM is a kind of amplitude and phase to be combined, 16QAM refers to 16 systems
Quadrature amplitude modulation.16QAM signals can be influenceed during transmission by phase noise and amplitude noise, cause phase to be sent out
Raw skew.The purpose of phase estimation is：Because laser has line width, so laser truly shakes can produce one near frequency
A little phase offsets, along with the error of offset estimation so that the symbol after offset estimation, its phase offset is still present, and
And this side-play amount changes over time, all scopes of 0 to 2 π can be covered.Here, carrier phase is first passed through to estimate to calculate
Method carries out carrier phase estimation to 16QAM signals, obtains first phase estimate, and first phase estimate includes phase noise
Influence, and phase noise of the signal in transmitting procedure can be influenceed by amplitude noise.
Carrying out the carrier phase algorithm for estimating of carrier phase estimation in the present invention to 16QAM signals has VV carrier phases to estimate
Algorithm, VV carrier phase estimated cascades maximum- likelihood estimation, blind phase search algorithm etc..Wherein, VV carrier phases are estimated
Algorithm is the influence that information phase is removed using the biquadratic computing of symbol, and the algorithm is a kind of feed forward type carrier phase recovery
Algorithm, without feedback control loop.VV carrier phase estimated cascades maximum- likelihood estimations can be used to further improve carrier wave phase
The precision of bit recovery algorithm, the signal after being recovered according to VV carrier phases algorithm for estimating enters the maximal possibility estimation of second stage
Algorithm, the estimate of phase noise is obtained according to maximum- likelihood estimation, and phase is recovered further according to estimate.Separately
Outward, also frequently with the classical blind phase search algorithm docking collection of letters number in 16 rank quadrature amplitude modulation coherent reception optical communication systems
Carrier phase recovery is carried out, blind phase search algorithm is while attempting different carrier phase angles, and determine wherein most possible
Value.It should be noted that every can estimate phase place change in 16QAM signals transmissions, and the calculation of phase noise can be eliminated
Method, belongs to the scope of protection of the invention, numerous to list herein.
S502, phase recovery is carried out according to first phase estimate to 16QAM signals, obtains the 16QAM after the first recovery
Signal.
Specifically, first phase estimate includes the influence of phase noise, 16QAM is believed according to first phase estimate
Number phase recovery is carried out, phase noise of the 16QAM signals in transmitting procedure can be eliminated.The purpose of carrier phase recovery is exactly
This fractional phase offset amount (i.e. phase noise) is removed, its symbol phase for exporting is used directly for symbol judgement.Carrier wave
The principle of phase recovery is to obtain the phase pushing figure in addition to information phase, and is removed from each symbol.In addition, carrier wave
Phase restoring module is located at after frequency deviation estimating modules, is also that two polarization states are independently carried out.Estimate to calculate by carrier phase
Method carries out phase recovery to 16QAM signals, not only eliminates most phase noise, and improves the line width of laser and holds
Limit.Here, after carrying out phase recovery to 16QAM signals according to first phase estimate, most phase noise is eliminated, this
Sample, can greatly reduce the error of the phase phase estimation when Kalman filtering algorithm is carried out after recovering.In addition, according to first
After phase estimation value carries out phase recovery to 16QAM signals, the line width tolerance limit of laser is improve, because Kalman filtering is calculated
Method is required to the line width of laser, Kalman filtering algorithm in the case of laser linewidth wide, due to by phase estimation
The limitation of scope so that phase estimation produces larger evaluated error, and passes through carrier phase estimation method proposed by the present invention,
Improve the line width tolerance limit of laser namely reduces the error of phase estimation in Kalman filtering algorithm.
S503, phase estimation is carried out by Kalman filtering algorithm to the 16QAM signals after recovery, is obtained second phase and is estimated
Evaluation.
Specifically, carrying out phase recovery by carrier phase algorithm for estimating and to the first estimate, eliminate most
Phase noise, but phase noise of the signal in transmitting procedure can be influenceed by amplitude noise, and estimated by carrier phase
The phase recovered after algorithm, is only a cancellation most of phase noise, and amplitude noise is not eliminated, and Kalman filtering is calculated
Method can be the optimal estimation algorithm for removing phase noise and amplitude noise simultaneously.The present invention is by Kalman filtering algorithm to extensive
16QAM signals after multiple carry out phase estimation, obtain second phase estimate, and second phase estimate includes that phase is made an uproar here
The influence of sound and amplitude noise, wherein, phase noise is remaining after phase recovery by carrying out to first phase estimate
Phase noise.
S504, carries out phase recovery, after obtaining the second recovery according to the second estimate to the 16QAM signals after recovery
16QAM signals.
Specifically, including the influence of phase noise and amplitude noise due to second phase estimate, filtered by Kalman
Ripple algorithm carries out phase recovery to the second estimate, can simultaneously remove the influence of phase noise and amplitude noise.Here, due to
Kalman filtering algorithm is required to the line width of laser, i.e., can be more preferably more accurately right in the case of narrow laser linewidth
16QAM signals carry out phase estimation, and in the case of laser linewidth wide, due to being limited by phase estimation scope, make
Obtain phase estimation and produce larger evaluated error.Carrier phase algorithm for estimating is first passed through, the line of Kalman filtering algorithm is improved
Tolerance limit, reduces decision error of the Kalman filtering algorithm in big line width system.Meanwhile, can by Kalman filtering algorithm
To realize the elimination of remaining phase noise and amplitude noise after carrier phase algorithm for estimating, the precision of algorithm is improve, made
A kind of carrier phase recovery method based on Kalman filtering algorithm for obtaining offer of the present invention can be realized under big line width system
The optimal estimation of Carrier Phase Noise and amplitude noise, so that the performance of lifting system.
As can be seen here, a kind of carrier phase recovery method based on Kalman filtering algorithm provided in an embodiment of the present invention and
Device, first pass through carrier phase algorithm for estimating carries out carrier phase estimation to 16QAM signals, obtains the estimate of carrier phase,
Then the estimate according to carrier phase is recovered to carrier phase, eliminates the most of phase noise in 16QAM signals, subtracts
Lacked the error of phase estimation, then by Kalman filtering algorithm, the signal after recovering to first phase carry out phase estimation and
Recover, so that phase noise and amplitude noise remaining in eliminating 16QAM signals, so, first pass through carrier phase algorithm for estimating
The most of phase noise in 16QAM signals is eliminated, the error of phase estimation is reduced, then by Kalman filtering algorithm to residual
Remaining phase noise and amplitude noise is eliminated, so that the performance of lifting system.
In an optional embodiment of the present invention, carrier wave phase is carried out to 16QAM signals by carrier phase algorithm for estimating
Position estimation, including：
Carrier phase estimation is carried out to 16QAM signals by VV carrier phases algorithm for estimating.
Viterbi-Viterbi carrier phase algorithm for estimating is proposed by Viterbi brothers, referred to as VV in the present invention
Carrier phase algorithm for estimating.VV carrier phase algorithm for estimating is the shadow that information phase is removed using the biquadratic computing of symbol
Ring, the algorithm is a kind of feed forward type carrier phase recovery algorithm, without feedback control loop.VV carrier phase algorithm for estimating is to answer
For in coherent reception system, removing the phase deviation between local oscillations and carrier wave, and phase remaining before algorithm
Error, to recover the algorithm of the original phase modulation of symbol.
Specifically, carrier phase estimation is carried out to 16QAM signals by VV carrier phases algorithm for estimating, including：
16QAM signals are carried out into QPSK segmentation, the carrier phase of 16QAM signals is obtained, carrier phase is at least
Including phase modulation information, phase noise and noise phase；
Specifically, before phase estimation is carried out to 16QAM signals, it is necessary to carry out piecemeal to 16QAM signals.By 16QAM
Signal is divided into different subregions (Class) according to amplitude, judges to meet QPSK (QPSK, Quadrature
Phase Shift Keying) feature subregion so that the phase value of the 16QAM signals after segmentation could meet VV carrier phases
The requirement of algorithm for estimating.Phase recovery thus can be carried out using VV carrier phases algorithm for estimating in each subregion.Its
In, QPSK is four kinds of out of phase differences using carrier wave characterizes the digital information of input, is quaternary phase-shift keying, i.e. four phases
Phase-shift keying (PSK), while QPSK is also, and a kind of availability of frequency spectrum is high, strong interference immunity several modulation systems, it is widely used in respectively
In kind communication system.
QPSK segmentation is carried out by by 16QAM signals, can obtain meeting the symbol of QPSK, QPSK will be met
Symbol as 16QAM signals carrier phase, carrier phase at least include phase modulation information, phase noise and spontaneous radiation
Amplify noise.Present invention assumes that receiver have been completed linear damage and frequency deviation compensation, only consider laser phase noise with
And the influence of noise (ASE) is amplified in the spontaneous radiation of link accumulation, k-th 16QAM symbol signal can be with table in X or Y polarization states
It is shown as：
Z (k)=s (k) exp { j φ (k) }+n (k)
Wherein, Z (k) is k-th 16QAM symbol signal in X or Y polarization states, and the value of Z (k) is generally plural number, and s (k) is hair
The 16QAM symbols for sending, φ (k) is the phase noise of laser, and n (k) is additivity ASE noises that average is zero.Wherein, in mathematics
In communication, commonly use time interval identical symbol to represent a binary digit, the signal in such time interval is referred to as
(binary system) code element, in addition, the noise phase in the present invention generally refers to ASE noises (i.e. spontaneous radiation amplification noise), ASE
Noise can be accumulated because the noise of amplifier and the error code that causes, relevant with amplifier step by step.Noise meeting is amplified in spontaneous radiation
Cause the change of phase and amplitude, so as to form phase noise and amplitude noise, main influence of the phase noise on receiver is
The signal to noise ratio for receiving signal is reduced, demodulation quality is reduced, increases the bit error rate, particularly some are to phase more sensitivity
Modulation system.Additivity ASE noises refer to a kind of noise being superimposed upon on signal, are usually denoted as n (k), and no matter have no signal,
Noise n (k) all exists all the time, can make signal that skew is produced in amplitude and phase.
In embodiments of the present invention, 16QAM signals are carried out into QPSK segmentation, including：
Obtain 16QAM signals corresponding constellation point on planisphere；
Specifically, the digital modulation of QPSK is described with planisphere, two of a kind of modulation technique defined in planisphere
Basic parameter：(1) signal distributions；(2) mapping relations and between modulation digital bit.Constellation point is defined in planisphere and is passed
Corresponding relation between defeated bit, this relation referred to as " maps ", and a kind of characteristic of modulation technique can be by signal distributions and having mapped
Full definition, you can come fully defining by planisphere.Therefore, first need to obtain 16QAM signals corresponding constellation point on planisphere,
QPSK segmentations could be carried out according to constellation point.
QPSK segmentation is carried out to constellation point, the corresponding subregion of constellation point is obtained；
Specifically, referring to Fig. 6, Fig. 6 is a kind of QPSK piecemeal schematic diagrames of 16QAM signals provided in an embodiment of the present invention.
As seen from Figure 6,16QAM signals are divided into three subregions, are respectively Class I, Class II and Class
The constellation point of III, wherein Class I and the subregions of Class III is black circle, and the constellation point of the subregions of Class II is soft dot, and
The constellation point of Class I and the subregions of Class III respectively at 45 °, 135 °, 225 °, on 315 ° of direction.
Subregion is adjudicated by amplitude, obtains meeting the phase signal of QPSK, and by the phase of QPSK
Position signal as 16QAM signals carrier phase.
Specifically, ruling out the 16QAM signals of Class I and Class III by amplitude from the signal for receiving, meet
The phase signal of QPSK.Wherein, QPSK is the phasing technique in M=4, and QPSK defines four kinds of carrier phases,
Respectively 45 °, 135 °, 225 °, 315 °.Here, the radius value of Class I and the subregions of Class III is fixed, receives signal
Each signaling point is a plural number, can calculate range value (the i.e. radius of signaling point circle in planisphere point of signaling point
Value), by this range value and Class I, the radius value contrast of Class III, you can in ruling out Class I and Class III
16QAM signals meet QPSK symbols.
According to formula：
Z ' (k)=exp { j θs(k)+φ(k)+θn}
Obtain being ruled out by amplitude the QPSK symbols (only considering phase information) of ClassI and ClassIII, wherein, Z ' (k) tables
Show the phase symbol of QPSK, θsK () represents k-th phase modulation of 16QAM symbol signals,
φ (k) is the phase noise of laser, θnNoise phase is represented, k represents 16QAM symbol signals.
After the phase signal for obtaining meeting QPSK, using the phase signal of the QPSK as
The carrier phase of 16QAM signals, because the phase signal for meeting QPSK could meet the estimation of VV carrier phases
The requirement of algorithm.Here, due to meeting the phase signal of QPSK in VV carrier phase algorithm for estimating is carried out four
The signal modulated after power operation can be eliminated, i.e. only have black circle in Fig. 6 and modulated after biquadratic operation is carried out
Signal can eliminate, therefore we need to be chosen from the 16QAM signals for receiving and meet the constellation point of QPSK signals, i.e.,
Then the signal of selection Class I and the subregions of Class III carries out phase as the carrier phase of 16QAM signals using these constellation points
Estimate position.
Referring to Fig. 7, Fig. 7 is a kind of fundamental block diagram of VV carrier phases algorithm for estimating provided in an embodiment of the present invention, specifically
Process is as follows：
Biquadratic computing removal phase modulation information is first passed through, obtains amplifying noise comprising phase noise and spontaneous radiation
Carrier phase；
First, the symbol of input is carried out biquadratic computing by VV algorithms, to remove phase modulation information θs(k), θs(k) table
Show k-th phase modulation of 16QAM symbol signals, only leave phase noise and noise phase.
According to formula：
(Z′(k))4=exp [the θ of 4 φ (k)+4n]
The carrier phase of 16QAM signals for only being influenceed by phase noise and noise phase is obtained, wherein, Z ' (k) is represented
The carrier phase of 16QAM signals, φ (k) is the phase noise of laser, θnNoise phase is represented, k represents that 16QAM code elements are believed
Number.Here, biquadratic computing is to carry out operating what is obtained by the real part and imaginary part to symbol, rather than directly by being input into symbol
Number phase multiplication arrived with 4, otherwise flagrant estimating can occur because of phase ambiguity in the boundary in phase span
Meter error.
Spontaneous radiation is eliminated further according to average calculating operation and amplify noise, obtain the estimate of the phase noise of carrier phase, phase
The estimate of position noise is first phase estimate.
Because laser phase rate of change is far below chip rate, it is basic in continuous several symbols can be considered as its
Keep constant, so several symbols for being successively inputted to algorithm, we regard it as one group, the phase error knot for estimating
Fruit is shared by all symbols of this group, i.e., adjacent some code elements can consider with same phase noise.If why will
Dry continuous symbol is divided into one group, also one important purpose, is just available with these symbols and removes to greatest extent to make an uproar
The influence of sound, although the phase of single symbol, due to the influence of noise, can make it have error with actual value, but due to random
The Gaussian characteristics of noise, the phase of continuous symbol is carried out averagely, can significantly suppress the influence of ASE noises such that it is able to
Phase error is estimated exactly.
Using θnAverage is characteristic, i.e., eliminate noise phase influence using average calculating operation.
According to formula：
The carrier phase of the 16QAM signals of the noise phase that is eliminated influence, wherein, Z ' (k) represents the load of 16QAM signals
Wave phase,It is the phase noise estimate of laser, k represents 16QAM symbol signals, and M is the length of average calculating operation, this
In, the selection of average calculating operation length needs compromise to consider phase noise and ASE noise intensities：Larger average length is conducive to disappearing
ASE influence of noises are gone, and less average length ensure that code element has identical phase noise so as to protect in average length
Demonstrate,prove the accuracy of phase estimation.
According to formula：
Obtain the estimate of the phase noise of carrier phaseWherein, Z ' (k) represents the carrier wave phase of 16QAM signals
Position,It is the phase noise estimate of laser, k represents 16QAM symbol signals, and M is the length of average calculating operation.Then mend
The error of carrier phase is repaid, here, the Carrier Phase Noise obtained using M sign computationM symbol will be common to enter
Line phase is compensated.
Finally, phase recovery is carried out to 16QAM signals according to first phase estimate, including：
The carrier phase of 16QAM signals is recovered according to first phase estimate, obtains the 16QAM after the first recovery
Signal, the 16QAM signals after the first recovery include phase noise and amplitude noise.
Specifically, the estimate according to phase noise recovers carrier phase, according to formula：
The signal after phase recovery is obtained, wherein, " (k) represents the carrier phase of the 16QAM signals after recovering, Z ' (k) to Z
The carrier phase of 16QAM signals is represented,It is the phase noise estimate of laser, k represents 16QAM symbol signals.This
In, the carrier phase of 16QAM signals is recovered according to first phase estimate, the 16QAM signals after the first recovery are obtained,
Because noise phase is not completely eliminated in the 16QAM signals after recovery, while the phase noise in signals transmission
Influenceed by amplitude noise, that is to say, that also there is remaining phase noise and amplitude noise in the 16QAM signals after recovery,
Therefore, it is necessary to the 16QAM signals after recovering to first carry out carrier phase recovery again, made an uproar with the carrier phase for realizing optimal
The estimation of sound and amplitude noise, so that lifting system performance.In addition, the size of laser phase noise, with the direct phase of its line width
Close, wherein, line width refers to that light is projected from laser, after laser starting of oscillation, has the generation of one or more longitudinal mode, each longitudinal mode
Frequency range be exactly laser line width.Therefore, the present invention is first passed through after VV carrier phases are estimated and carries out phase recovery, to disappear
Except most of phase noise, the error of phase estimation in Kalman filtering algorithm is reduced.
In embodiments of the present invention, phase estimation is carried out to the 16QAM signals after recovery by Kalman filtering algorithm, is joined
See the fundamental block diagram that Fig. 8, Fig. 8 are a kind of Kalman filtering algorithm provided in an embodiment of the present invention, implement process as follows：Obtain
The Carrier Phase Noise estimate of the previous moment at current time is taken, Space admittance according to Kalman filtering algorithm and preceding
The Carrier Phase Noise estimate at one moment, obtains prior estimate and prior estimate that the Carrier Phase Noise at current time is estimated
Error, Space admittance includes the actual value of the phase noise of the carrier phase at current time；
Specifically, Kalman filtering algorithm is using signal and the state-space model of noise, using the carrier wave of previous moment
The estimate of phase noise and the measured value at current time update the estimation to state variable, obtain the carrier wave phase at current time
The estimate of position noise.
Wherein, Space admittance is used for illustrating the model of the variable to be estimated, the spatiality of Kalman filtering algorithm
Model, can be formulated as：
θk=θk-1+ωk
Wherein, rkThe input signal that expression is received, akRepresent and send code element, θkK-th phase noise of code element is represented,
θk-1Represent the phase noise of -1 code element of kth, ωkThe residual quantity between k moment and k-1 moment phase noises is represented,Represent card
The state value of the phase noise that Kalman Filtering is estimated, n 'kRepresent the noise that carrier phase is estimated.Can be with by Space admittance
Obtain the state value of the phase noise of the carrier phase at current timeThe state value i.e. phase of phase noise here are made an uproar
The actual value of sound.Here, due to being a random quantity by the quantity of state of noise jamming, it is impossible to measure exact value, but it can be entered
A series of observations of row, and according to a group observations, it is estimated by certain Statistics.Make estimate as precisely as possible
Close to actual value, here it is optimal estimation.The difference of actual value and estimate is referred to as evaluated error.If the mathematic expectaion of estimate with
Actual value is equal, this to estimate to be referred to as unbiased esti-mator.The recursion optimal estimation that Kalman proposes is theoretical, adoption status spatial description
Method, recursive form is used in algorithm, and Kalman filtering can process the random process of many peacekeeping non-stationaries.
After the carrier phase estimate of the previous moment for obtaining current time, then calculated further according to Kalman filtering
The Space admittance of method and the carrier phase estimate of previous moment, it is possible to obtain the Carrier Phase Noise at current time
Prior estimate, is represented with equation below：
Wherein,Priori estimates of the carrier phase at the k moment are represented,Represent carrier phase in k-1
The estimate at moment, ωkRepresent the residual quantity between k moment and k-1 moment phase noises.
Carrier phase prior estimate error according to current time, obtains the Carrier Phase Noise prior estimate at current time
Error covariance；
According to formula：
Pk|k-1=Pk-1|k-1+Qk
The error covariance of the Carrier Phase Noise prior estimate at current time is obtained, wherein, Pk|k-1Represent k moment carrier waves
The error covariance of phase noise prior estimate, Pk-1|k-1Represent the error covariance of k-1 moment Carrier Phase Noises, QkRepresent
Estimate noise variance.
Then, Error weight is adjusted by kalman gain, according to formula：
Kalman gain is obtained, wherein, KkRepresent the kalman gain at k moment, Pk|k-1Represent k moment Carrier Phase Noises
The error covariance of prior estimate, HkLinearization measurement transition matrix is represented,The conjugation of linearization measurement transition matrix is represented,
RkRepresent observation noise variance.Wherein linearization measurement transition matrix can be represented with equation below：
Wherein, HkRepresent linearization measurement transition matrix, akRepresent and send code element,Represent carrier phase in k
The priori estimates at quarter.
The measured value of the Carrier Phase Noise at current time is obtained, the elder generation that the Carrier Phase Noise at current time is estimated is calculated
The error estimated with measured value is tested, the prior estimate of Carrier Phase Noise estimation and the prediction of measured value for obtaining current time are missed
Difference.
According to formula：
Prior estimate and the error of measured value that the Carrier Phase Noise at current time is estimated are calculated, current time is obtained
Prior estimate and the predicated error of measured value that Carrier Phase Noise is estimated.Wherein, vkRepresent the predicated error at k moment, rkRepresent
The input signal that k receptions are arrived,Represent k receptions to the priori estimates of input signal values, akRepresent the k moment
Transmission code element,Represent priori estimates of the carrier phase at the k moment.Here, k receptions are to input signal values rk
Be by first to k receptions to the input signal Decision (judgement) that carries out in hard decision, i.e. Fig. 8, obtain the k moment
Send code element ak, then according to carrier phase the k moment priori estimatesThe common predicated error for solving the k moment,
Pass through kalman gain K againkRegulation Error weight, finally again with carrier phase the k moment priori estimatesObtain
Posterior estimate of the carrier phase at the k momentWhat the priori estimates i.e. by the k moment were obtained after amendment is the k moment
Posterior estimator, namely the k moment optimal estimation, here,It is by the Delay (delay) in Fig. 8, i.e. k moment
Prior estimateIt is the estimate by the k-1 momentObtain.Kalman filtering algorithm is one as can be seen here
Plant and optimize autoregression data processing method.
According to the predicated error, the prior estimate that the Carrier Phase Noise at current time is estimated, and current time are updated
Carrier Phase Noise prior estimate error covariance, obtain the Posterior estimator of the Carrier Phase Noise at current time, and work as
The error covariance of the Posterior estimator of the Carrier Phase Noise at preceding moment.
According to formula：
Obtain posterior estimate of the carrier phase at the k momentThat is the Posterior estimator of k moment carrier phases, wherein,Posterior estimate of the carrier phase at the k moment is represented,Represent priori estimates of the carrier phase at the k moment, Kk
Represent the kalman gain at k moment, vkRepresent the predicated error at k moment.
Here, although have been obtained for posterior estimate of the carrier phase at the k momentBut it is intended to make Kalman
Wave filter constantly go down until systematic procedure terminates by operation, in addition it is also necessary to updates the covariance of the prior estimate at k moment.
According to formula：
Pk|k=(1-KkHk)Pk|k-1
The covariance of the prior estimate at k moment is updated, wherein, Pk|kRepresent k moment carrier phase Posterior estimator errors association side
Difference matrix, Pk|k-1Represent the error covariance of k moment Carrier Phase Noise prior estimates, KkThe kalman gain at k moment is represented,
HkRepresent linearization measurement transition matrix.
It can be seen that, Kalman filtering algorithm is the optimal State Estimation filtering algorithm with Minimum Mean Square Error as criterion, and it is not required to
Past measured value is stored, recurrence calculation is only carried out according to the estimate of current observation and previous moment, just can realized
Estimation to live signal, with memory data output it is small, algorithm is easy the characteristics of.
Finally, phase recovery is carried out to the 16QAM signals after recovery according to the second estimate, including：
Enter line phase to the 16QAM signals after recovery according to the second estimate to untwist, obtain the letters of the 16QAM after the second recovery
Number.
Specifically, the scheme that phase is untwisted mainly has two kinds, a kind of is traditional quadrature frequency conversion scheme, and another kind is multiple
Several schemes of being untwisted to phase, both schemes are all based on the principle of Digital Down Convert, have and typically realize structure, but are closed two
In one receiver, selection plural number untwists scheme to phase advantageously.The two schemes that receiver phase untwists all are classical
Carrier wave stripping means.Main in general receiver to be untwisted scheme using quadrature frequency conversion phase, feature is in radio-frequency channel
Analog down requirement than relatively low.Using plural the more of scheme of being untwisted to phase in high performance receiver, feature is output
Signal does not include new frequency in addition to approximate zero intermediate frequency signals, for base band signal process is provided conveniently.
Referring to Fig. 9, Fig. 9 is a kind of model polar plot that carrier phase provided in an embodiment of the present invention estimates input signal；
Fig. 9 mainly shows a kind of model vector of carrier phase estimation input signal in carrier phase algorithm for estimating proposed by the present invention
Figure.Phase estimation is generally dependent on the average value of filter length in carrier phase algorithm for estimating, to eliminate the shadow of ASE noises
Ring.However, it is difficult to find an optimal length, because if block length selection is shorter, carrier wave phase can be accurately tracked by
Position, and block length selection is more long, can well eliminate ASE influence of noises.Therefore, common carrier phase algorithm for estimating,
Transmission code element after recovery also has the residual phase noise or amplitude noise or both to have.As shown in figure 9, rkWhat expression was received
Input signal, akRepresent and send code element, θkRepresent k-th phase noise of code element, n 'kThe noise that carrier phase is estimated is represented,
Represent amplitude noise, nkRepresent ASE noises.It can be seen that, this kind of CPE (estimate by Carrier Phase Estimation, carrier phase
Meter) algorithm only considered n 'kInfluence, without considerSo the signal element after recovering is(CPE),
Referring to Figure 10, Figure 10 is another model vector that carrier phase provided in an embodiment of the present invention estimates input signal
Figure, Figure 10 shows a kind of model polar plot of carrier phase estimation input signal in the Kalman filtering algorithm in the present invention.
Calculated with plural number during calculation error in Kalman filtering algorithm, it is contemplated thatEffect, so in the imaginary part of error update value
Comprising amplitude information, by CPANE (Carrier Phase and Amplitude Noise Estimation, carrier phase
Estimate with amplitude noise) improve algorithm performance.But belong to the algorithm of decision-feedback due to this kind of algorithm, its algorithm performance depends on
In decision error.So, algorithm performance high can be realized in the case of narrow laser linewidth；And in the feelings of laser linewidth wide
Under condition, can be limited by phase estimation scope, be produced larger evaluated error.But common carrier phase is first passed through to estimate to calculate
Method eliminates the influence of most of phase noise, can lift the line width tolerance limit of Kalman filtering algorithm, reduces Kalman filtering and calculates
Decision error of the method under big line width system.As shown in Figure 10, rkThe input signal that expression is received, akRepresent and send code element, θk
Represent k-th phase noise of code element, n 'kThe noise that carrier phase is estimated is represented,Represent amplitude noise, nkRepresent that ASE makes an uproar
Sound.Compared with common carrier phase algorithm for estimating, common carrier phase algorithm for estimating only considered n 'kInfluence, and do not have
There is considerationSo the signal element after recovering isAnd Kalman filtering algorithm can simultaneously to the phase of signal
Noise and amplitude noise are eliminated, and the code element after recovery is
Referring to Figure 11, Figure 11 is a kind of carrier phase recovery based on Kalman filtering algorithm provided in an embodiment of the present invention
The structural representation of device, including such as lower module：
First phase estimation module 1101, for carrying out carrier phase to 16QAM signals by carrier phase algorithm for estimating
Estimate, obtain first phase estimate；
First phase recovery module 1102, for carrying out phase recovery to 16QAM signals according to first phase estimate, obtains
16QAM signals after recovering to first；
Second phase estimation module 1103, for carrying out phase to the 16QAM signals after recovery by Kalman filtering algorithm
Position estimation, obtains second phase estimate；
Second phase recovery module 1104, it is extensive for entering line phase to the 16QAM signals after recovery according to the second estimate
It is multiple, obtain the 16QAM signals after the second recovery.
Further, first phase estimation module 1101, including：
First phase estimates submodule, for carrying out carrier phase to 16QAM signals by VV carrier phases algorithm for estimating
Estimate.
Further, first phase estimates submodule, including：
Cutting unit, for 16QAM signals to be carried out into QPSK segmentation, obtains the carrier phase of 16QAM signals,
Carrier phase at least includes phase modulation information, phase noise and noise phase；
Removal unit, for removing phase modulation information by biquadratic computing, obtains comprising phase noise and noise phase
The carrier phase of position；
Estimation unit, for eliminating noise phase according to average calculating operation, obtains the estimate of the phase noise of carrier phase,
The estimate of phase noise is first phase estimate.
Further, cutting unit, specifically for：
Obtain 16QAM signals corresponding constellation point on planisphere；
QPSK segmentation is carried out to constellation point, the corresponding subregion of constellation point is obtained；
Subregion is adjudicated by amplitude, obtains meeting the phase signal of QPSK, and by the phase of QPSK
Position signal as 16QAM signals carrier phase.
As can be seen here, a kind of carrier phase recovery device based on Kalman filtering algorithm provided in an embodiment of the present invention,
First pass through first phase estimation unit carries out carrier phase estimation to 16QAM signals, obtains the estimate of carrier phase, Ran Hougen
Carrier phase is recovered according to first phase recovery unit, eliminates the most of phase noise in 16QAM signals, reduce phase
The error that position is estimated, then by second phase estimation unit, the signal after recovering to first phase carries out phase estimation, then passes through
Second phase recovery unit carries out phase recovery, so that phase noise and amplitude noise remaining in eliminating 16QAM signals, this
Sample, first passes through most of phase noise that the VV carrier phases algorithm for estimating of first phase estimation unit is eliminated in 16QAM signals,
The error of phase estimation is reduced, then remaining phase noise and amplitude noise are eliminated by Kalman filtering algorithm,
So as to the performance of lifting system.
It should be noted that herein, such as first and second or the like relational terms are used merely to a reality
Body or operation make a distinction with another entity or operation, and not necessarily require or imply these entities or deposited between operating
In any this actual relation or order.And, term " including ", "comprising" or its any other variant be intended to
Nonexcludability is included, so that process, method, article or equipment including a series of key elements not only will including those
Element, but also other key elements including being not expressly set out, or also include being this process, method, article or equipment
Intrinsic key element.In the absence of more restrictions, the key element limited by sentence "including a ...", it is not excluded that
Also there is other identical element in process, method, article or equipment including the key element.
Each embodiment in this specification is described by the way of correlation, identical similar portion between each embodiment
Divide mutually referring to what each embodiment was stressed is the difference with other embodiment.Especially for system reality
Apply for example, because it is substantially similar to embodiment of the method, so description is fairly simple, related part is referring to embodiment of the method
Part explanation.
Presently preferred embodiments of the present invention is the foregoing is only, is not intended to limit the scope of the present invention.It is all
Any modification, equivalent substitution and improvements made within the spirit and principles in the present invention etc., are all contained in protection scope of the present invention
It is interior.
Claims (10)
1. a kind of carrier phase recovery method based on Kalman filtering algorithm, is applied to 16 ary quadrature Modulation and Amplitude Modulation 16QAM
Coherent transmission system, it is characterised in that methods described includes：
Carrier phase estimation is carried out to 16QAM signals by carrier phase algorithm for estimating, first phase estimate is obtained；
Phase recovery is carried out to the 16QAM signals according to the first phase estimate, the letters of the 16QAM after the first recovery are obtained
Number；
Phase estimation is carried out to the 16QAM signals after the recovery by Kalman filtering algorithm, second phase estimate is obtained；
Phase recovery is carried out to the 16QAM signals after the recovery according to second estimate, after obtaining the second recovery
16QAM signals.
2. method according to claim 1, it is characterised in that it is described by carrier phase algorithm for estimating to 16QAM signals
Carrier phase estimation is carried out, including：
Carrier phase estimation is carried out to the 16QAM signals by VV carrier phases algorithm for estimating.
3. method according to claim 2, it is characterised in that it is described by VV carrier phase algorithm for estimating to described
16QAM signals carry out carrier phase estimation, including：
The 16QAM signals are carried out into QPSK segmentation, the carrier phase of the 16QAM signals, the carrier wave is obtained
Phase at least includes phase modulation information, phase noise and noise phase；
The phase modulation information is removed by biquadratic computing, the institute comprising the phase noise and the noise phase is obtained
State carrier phase；
The noise phase is eliminated according to average calculating operation, the estimate of the phase noise of the carrier phase is obtained, it is described
The estimate of phase noise is the first phase estimate.
4. method according to claim 3, it is characterised in that described that the 16QAM signals are carried out into QPSK
Segmentation, obtains the carrier phase of the 16QAM signals, including：
Obtain the 16QAM signals corresponding constellation point on planisphere；
The QPSK segmentation is carried out to the constellation point, the corresponding subregion of the constellation point is obtained；
The subregion is adjudicated by amplitude, obtains meeting the phase signal of the QPSK, and by the quaternary phase shift
The phase signal of keying as the 16QAM signals carrier phase.
5. method according to claim 4, it is characterised in that described after Kalman filtering algorithm is to the recovery
16QAM signals carry out phase estimation, including：
The Carrier Phase Noise estimate of the previous moment at current time is obtained, according to the space shape of the Kalman filtering algorithm
The Carrier Phase Noise estimate of states model and the previous moment, obtains the Carrier Phase Noise estimation at the current time
Prior estimate and prior estimate error, the Space admittance include the phase noise of the carrier phase at the current time
Actual value；
Carrier phase prior estimate error according to the current time, obtains the Carrier Phase Noise priori at the current time
The error covariance of estimation；
The measured value of the Carrier Phase Noise at the current time is obtained, the Carrier Phase Noise for calculating the current time is estimated
Prior estimate and the measured value error, obtain the current time Carrier Phase Noise estimate prior estimate and institute
State the predicated error of measured value；
According to the predicated error, the prior estimate that the Carrier Phase Noise at the current time is estimated is updated, and it is described current
The error covariance of the Carrier Phase Noise prior estimate at moment, the posteriority for obtaining the Carrier Phase Noise at the current time is estimated
Meter, and the current time Carrier Phase Noise Posterior estimator error covariance.
6. method according to claim 1, it is characterised in that it is described according to second estimate to the recovery after
16QAM signals carry out phase recovery, including：
Enter line phase to the 16QAM signals after the recovery according to second estimate to untwist, after obtaining the second recovery
16QAM signals.
7. a kind of carrier phase recovery device based on Kalman filtering algorithm, is applied to 16QAM coherent transmission systems, its feature
It is that described device includes：
First phase estimation module, for carrying out carrier phase estimation to 16QAM signals by carrier phase algorithm for estimating, obtains
First phase estimate；
First phase recovery module, for carrying out phase recovery to the 16QAM signals according to the first phase estimate, obtains
16QAM signals after recovering to first；
Second phase estimation module, estimates for entering line phase to the 16QAM signals after the recovery by Kalman filtering algorithm
Meter, obtains second phase estimate；
Second phase recovery module, it is extensive for entering line phase to the 16QAM signals after the recovery according to second estimate
It is multiple, obtain the 16QAM signals after the second recovery.
8. device according to claim 7, it is characterised in that the first phase estimation module, including：
First phase estimates submodule, for carrying out carrier phase estimation to 16QAM signals by VV carrier phases algorithm for estimating.
9. device according to claim 8, it is characterised in that the first phase estimates submodule, including：
Cutting unit, for the 16QAM signals to be carried out into QPSK segmentation, obtains the carrier wave of the 16QAM signals
Phase, the carrier phase at least includes phase modulation information, phase noise and noise phase；
Removal unit, for removing the phase modulation information by biquadratic computing, obtains comprising the phase noise and institute
State the carrier phase of noise phase；
Estimation unit, for eliminating the noise phase according to average calculating operation, obtains the phase noise of the carrier phase
Estimate, the estimate of the phase noise is the first phase estimate.
10. device according to claim 9, it is characterised in that the cutting unit, specifically for：
Obtain the 16QAM signals corresponding constellation point on planisphere；
The QPSK segmentation is carried out to the constellation point, the corresponding subregion of the constellation point is obtained；
The subregion is adjudicated by amplitude, obtains meeting the phase signal of the QPSK, and by the quaternary phase shift
The phase signal of keying as the 16QAM signals carrier phase.
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| WO2020052683A1 (en) * | 2018-09-13 | 2020-03-19 | 中兴通讯股份有限公司 | Frequency offset estimation and compensation method and apparatus, communication device, and computer readable storage medium |
| CN109000782A (en) * | 2018-09-27 | 2018-12-14 | 哈尔滨工程大学 | A kind of ellipse fitting non-linear error calibration method based on Kalman filtering |
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| CN114726439B (en) * | 2022-03-11 | 2023-05-05 | 西南交通大学 | Visible light communication single carrier and multi-carrier modulation method based on KK relation |
| CN116260690A (en) * | 2023-05-12 | 2023-06-13 | 长沙先度科技有限公司 | Carrier phase tracking method for QAM weak signals |
| CN116319211A (en) * | 2023-05-12 | 2023-06-23 | 长沙先度科技有限公司 | Multi-order Kalman carrier tracking method, tracking loop and signal receiver for QAM signals |
| CN116260690B (en) * | 2023-05-12 | 2023-07-21 | 长沙先度科技有限公司 | Carrier phase tracking method for QAM weak signals |
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