CN109756436A - The sub-carriers modulation format recognition methods of OFDM-EON system and device - Google Patents
The sub-carriers modulation format recognition methods of OFDM-EON system and device Download PDFInfo
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Abstract
The embodiment of the present invention provides a kind of OFDM-EON system sub-carriers modulation format recognition methods and device, the described method includes: calculating the signal MMS value of each subcarrier in the X polarization and Y polarization of OFDM-EON system, and calculate the MMS average value that identical number subcarrier is corresponded in the X polarization and Y polarization；The various default modulation formats are ranked up according to the MMS value of a variety of default modulation formats, using the average value of the MMS value of two kinds of the arbitrary neighborhood default modulation formats after sequence as decision threshold；The corresponding average value of each number is compared with each decision threshold, the modulation format of the subcarrier of each number is determined according to comparison result.The embodiment of the present invention can intelligently, quickly and steadily identify the subcarrier-modulated format of dynamic change in OFDM-EON system, all have stronger tolerance to polarization mode dispersion, laser phase noise and frequency deviation.
Description
Technical field
The embodiment of the present invention belongs to technical field of optical fiber communication, carries more particularly, to a kind of OFDM-EON system neutron
The recognition methods of wave modulation format and device.
Background technique
In order to meet the ever-increasing capacity requirement of global ip flow, and further increase the frequency spectrum benefit of optical fiber telecommunications system
With efficiency, in recent years, optical-fiber network just distributes evolution from frequency spectrum grid fixed at present to following elastic frequency spectrum.Currently, scholar
Have proposed based on coherent light OFDM (Orthogonal Frequency Division Multiplexing, orthogonal frequency division multiplexing
With) elastic optical network (Elastic Optical Networks, EON) framework, be abbreviated as OFDM-EON.OFDM-EON is used
Finer frequency spectrum grid and adaptive-bandwidth transceiver, adaptively changes a variety of transmitter parameters, including modulation format, band
Width, number of subcarriers etc..The frequency spectrum scheduling of " just enough " is provided to each connection requirement to meet the flow demand of dynamic change.
This network is greatly improved relative to existing dense wavelength division multiplexing system, spectrum efficiency.
At present for the research of OFDM-EON mainly around three physical layer, the network planning and control layer technology major class exhibitions
It opens.However, the research of elastic transceiver is assumed to have known each seed ginseng of transmitting signal in advance in OFDM-EON signal receiving end
Number, and the actual transmissions situation grave fault of this point and OFDM-EON signal.Reason is each of OFDM-EON transmitting signal
Kind parameter carries out dynamic adjustment in transmission range, optical channel noise characteristic and the customer flow variation with optical fiber always.Therefore, when
When the important parameter dynamic change of EON transmitter, coherent receiver how to be made intelligently to adapt to transmitting signal in the shortest time
The variation of frequency spectrum and constellation mapping is the correct premise for carrying out the reception of OFDM-EON signal and demodulation, with important theory and
Practice significance.
In addition, realizing the fine-grained management to optical-fiber network, it is ensured that bandwidth resources to reduce the operation cost of dynamic optical network
Optimum utilization, it is necessary in the key node of EON to each light transmission path carry out optical signal to noise ratio (Optical Signal
Noise Ratio, OSNR), chromatic dispersion, the channel impairments such as polarization mode dispersion and Polarization Dependent Loss real-time monitoring, and this
Kind monitors and uses the modulation format of photon carrier wave closely related.Therefore, OFDM-EON system sub-carriers modulation format is realized
Identification can provide strong theory for the coherent reception of EON signal in next generation's optic communication backbone network and optical information networks
And technical support.
The EON modulation format recognition methods having proposed at present can substantially be divided into 4 classes: (1) data householder method, including be based on
Data householder method, by adding the light OFDM rate transmission method of physical layer leading symbol and based on the tune of frequency pilot sign
Format identification method processed etc.；(2) based on the recognition methods of mathematical feature, including based on higher order statistical and principal component analysis technology
Modulation format recognition methods, asynchronous time delay tap drawing practice are based on signal power distribution and peak-to-average power ratio method etc.；(3)
Artificial intelligence recognition methods, variable Bayes's expectation maximization method and cluster including being based on the space Stokes (Stokes)
Algorithm etc.；(4) physical layer attributes method and the recognition methods based on optical waveguide etc..These methods are mainly for single carrier EON system
The modulation format of system identifies that computation complexity is high, and recognition performance has to be hoisted when OSNR is lower, is not directed to OFDM-EON system
The identification of system subcarrier-modulated format.
In addition, there are also dispersion-average power signal sample of various known modulation format signals and dispersion-signal is flat
Equal power measured value array is matched, and realizes modulation format identification；And it is calculated not in the space Stokes (Stokes)
With the Higher Order Cumulants of modulation format, suitable characteristic parameter is extracted and selected, realizes the identification to common modulation format；It is based on
The asynchronous delay method of sampling, the variance for calculating test signal are modulated format identification etc..These methods are primarily adapted for use in single load
The modulation format of wave EON system identifies that calculation amount is larger, can not be suitable for the knowledge of OFDM-EON system sub-carriers modulation format
Not.
Summary of the invention
To overcome the problems, such as that above-mentioned existing subcarrier-modulated format identification method can not be suitable for OFDM-EON or extremely
It partially solves the above problems, the embodiment of the present invention provides a kind of OFDM-EON system sub-carriers modulation format recognition methods
And device.
According to a first aspect of the embodiments of the present invention, a kind of OFDM-EON system sub-carriers modulation format identification side is provided
Method, comprising:
Calculate MMS (the Modulus Mean of each sub-carrier signal in the X polarization and Y polarization of OFDM-EON system
Square, mould are square) value, and calculate the MMS average value that the subcarrier of identical number is corresponded in the X polarization and Y polarization；
The various default modulation formats are ranked up according to the MMS value of a variety of default modulation formats, by the successor that sorts
Anticipate adjacent two kinds of default modulation formats MMS average value as decision threshold；
The corresponding average value of each number is compared with each decision threshold, each institute is determined according to comparison result
State the modulation format of the subcarrier of number.
Second aspect according to embodiments of the present invention provides a kind of OFDM-EON system sub-carriers modulation format identification dress
It sets, comprising:
First computing module, the X for calculating OFDM-EON system polarize the MMS value with each sub-carrier signal in Y polarization,
And calculate the MMS average value that the subcarrier of identical number is corresponded in the X polarization and Y polarization；
Second computing module, for according to the MMS values of a variety of default modulation formats to the various default modulation formats into
Row sequence, using the MMS average value of two kinds of the arbitrary neighborhood default modulation formats after sequence as decision threshold；
Determining module, for the corresponding average value of each number to be compared with each decision threshold, according to than
Relatively result determines the modulation format of the subcarrier of each number.
In terms of third according to an embodiment of the present invention, a kind of electronic equipment is also provided, comprising:
At least one processor；And
At least one processor being connect with the processor communication, in which:
The memory is stored with the program instruction that can be executed by the processor, and the processor calls described program to refer to
Order is able to carry out OFDM-EON system sub-carriers modulation format recognition methods provided by first aspect, can be various possibility
Implementation in any possible implementation.
4th aspect according to an embodiment of the present invention, also provides a kind of non-transient computer readable storage medium, described
Non-transient computer readable storage medium stores computer instruction, and the computer instruction makes the computer execute first aspect
Provided OFDM-EON system sub-carriers modulation format recognition methods can be any in various possible implementations
Possible implementation.
The embodiment of the present invention provides a kind of OFDM-EON system sub-carriers modulation format recognition methods and device, this method
And X polarization and the average value of the MMS value of identical number sub-carrier signal in Y polarization that device passes through calculating OFDM-EON system
MMSsub, decision threshold is determined according to the MMS value of default modulation format, by MMSsubValue is compared with decision threshold, is identified
The modulation format of each number subcarrier, thus intelligence, son that is quick and steadily identifying dynamic change in OFDM-EON system
Multicarrier modulation format, and stronger tolerance is all had for polarization mode dispersion, laser phase noise and frequency deviation.
Detailed description of the invention
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technical description to make simple introduction.It should be evident that the accompanying drawings in the following description is the present invention
Some embodiments for those of ordinary skill in the art without creative efforts, can also basis
These attached drawings obtain other attached drawings.
Fig. 1 is that OFDM-EON system sub-carriers modulation format recognition methods overall flow provided in an embodiment of the present invention is shown
It is intended to；
Fig. 2 is that modulation lattice are preset in OFDM-EON system subcarrier modulation format recognition methods provided in an embodiment of the present invention
Each annular radii schematic diagram of the planisphere of formula；
Fig. 3 is another stream of subcarrier-modulated format identification method in OFDM-EON system provided in an embodiment of the present invention
Journey schematic diagram；
Fig. 4 is the emulation system of subcarrier-modulated format identification method in OFDM-EON system provided in an embodiment of the present invention
System schematic diagram；
Fig. 5 is in OFDM-EON system subcarrier modulation format recognition methods provided in an embodiment of the present invention, and different sons carry
The MMS value of wave modulation format is with OSNR change curve；
Fig. 6 is in OFDM-EON system subcarrier modulation format recognition methods provided in an embodiment of the present invention, in every sub- load
The MMS value of subcarrier is with OSNR change curve under the conditions of wave different data points；
Fig. 7 is in OFDM-EON system subcarrier modulation format recognition methods provided in an embodiment of the present invention, in different frequencies
The MMS value of different sub-carrier modulation format is with OSNR change curve under the conditions of partially；
Fig. 8 is in OFDM-EON system subcarrier modulation format recognition methods provided in an embodiment of the present invention, in different DGD
Under the conditions of different sub-carrier modulation format MMS value with OSNR change curve；
Fig. 9 is in OFDM-EON system subcarrier modulation format recognition methods provided in an embodiment of the present invention, and subcarrier makes
Influence of the different data points of every subcarrier to MFRR when being modulated with QPSK or 8QAM；
Figure 10 is to be used in mixed way in OFDM-EON system subcarrier modulation format recognition methods provided in an embodiment of the present invention
Under more modulation format condition, the MFRR of every subcarrier is with OSNR change curve；
Figure 11 is hybrid modulation in OFDM-EON system subcarrier modulation format recognition methods provided in an embodiment of the present invention
Under the conditions of be modulated format identification after, the BER of system is with OSNR change curve；
Figure 12 is OFDM-EON provided in an embodiment of the present invention transmitting, transmission and coherent reception experimental system sub-carriers tune
The structural block diagram of format identification method processed；
Figure 13 is in OFDM-EON system subcarrier modulation format recognition methods provided in an embodiment of the present invention, in experiment item
The MMS value of lower five kinds of part typical modulation formats is with OSNR change curve；
When Figure 14 is OFDM-EON system hybrid modulation provided in an embodiment of the present invention, under experiment and simulated conditions, benefit
With the recognition success rate of subcarrier-modulated format identification method with OSNR change curve；
Figure 15 is subcarrier-modulated format identification device overall structure in OFDM-EON system provided in an embodiment of the present invention
Schematic diagram；
Figure 16 is in OFDM-EON system provided in an embodiment of the present invention, and subcarrier-modulated format identification electronic equipment is whole
Structural schematic diagram.
Specific embodiment
In order to make the object, technical scheme and advantages of the embodiment of the invention clearer, below in conjunction with the embodiment of the present invention
In attached drawing, technical scheme in the embodiment of the invention is clearly and completely described.Obviously, described embodiment is
A part of the embodiment of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, those of ordinary skill in the art
Every other embodiment obtained without making creative work, shall fall within the protection scope of the present invention.
A kind of OFDM-EON system sub-carriers modulation format recognition methods is provided in one embodiment of the invention, is schemed
1 is OFDM-EON system sub-carriers modulation format recognition methods overall flow schematic diagram provided in an embodiment of the present invention, the party
Method includes: S101, calculates the MMS value of each subcarrier in the X polarization and Y polarization of OFDM-EON system, and calculate X polarization and
The MMS average value of the subcarrier of identical number is corresponded in the Y polarization；
Specifically, before the MMS value for calculating each subcarrier, first each sub-carrier signal is pre-processed.According to OFDM-
The planisphere of each subcarrier, calculates the MMS value of each sub-carrier signal in the X polarization and Y polarization of EON system.Assuming that OFDM-EON
The subcarrier of different numbers uses one of a variety of default modulation formats, different numbers in Y polarization at random in the X polarization of system
Subcarrier use one of a variety of default modulation formats at random.The number of each subcarrier is different in X polarization, Y polarization
In each subcarrier number it is different, X polarize sub-carriers number with Y polarize sub-carriers number it is corresponding identical.And
It is assumed that the subcarrier of identical number uses same modulation format.Such as the number of each subcarrier is respectively 1,2,3 and in X polarization
The number of each subcarrier is also respectively 1,2,3 and 4 in 4, Y polarizations.The son load of identical number is corresponded in calculating X polarization and Y polarization
The MMS average value MMS of wavesub.MMS as numbered the subcarrier that number is 1 in the subcarrier for being 1 and Y polarization in X polarization is average
Value be number is 1 in X polarization subcarrier MMS value plus numbering the summation of the subcarrier MMS value for being 1 in Y polarization divided by 2, from
And reduce the influence of channel equalization performance.
S102 is ranked up the various default modulation formats according to the MMS value of a variety of default modulation formats, will sort
The MMS average value of two kinds of the arbitrary neighborhood default modulation formats is as decision threshold afterwards；
In order to identify the modulation format of each subcarrier, need to choose decision threshold appropriate.Wherein, the default tune of subcarrier
Format processed is preset common modulation format in OFDM-EON system, and such as five kinds of default modulation formats of setting are QPSK
(Quadrature Phase Shift Keyin, quadrature phase shift keying), 8QAM (8-ary quadrature amplitude
Modulation, 8 ary quadrature amplitudes), 16QAM (16-ary quadrature amplitude modulation, 16
Ary quadrature amplitude), 32QAM (32-ary quadrature amplitude modulation, 32 Quadrature Amplitudes
Modulation) and 64QAM (64-ary quadrature amplitude modulation, 64 ary quadrature amplitudes), or
A variety of in this five kinds of default modulation formats, the present embodiment is not limited to this five kinds of default modulation formats.According to various default modulation
The planisphere of format, as shown in Fig. 2, calculating the MMS value of every kind of default modulation format.On the planisphere of various default modulation formats
Maximum radius is set as 1, but is not limited to this setting.The MMS value that above-mentioned five kinds of default modulation formats are calculated is respectively as follows:
MMSQPSK=(4 × r1 2)/4=(4 × 12)/4=1；
Various default modulation formats are ranked up according to the MMS value of default modulation format.Such as by above-mentioned five kinds default tune
The MMS value of format processed is ranked up according to sequence from big to small, i.e., 1,0.6111,0.5882,0.5556 and 0.4286, thus
Determine default modulation format is ordered as QPSK, 8QAM, 32QAM, 16QAM and 64QAM.After sorting described in two kinds of arbitrary neighborhood
The MMS average value of default modulation format is as decision threshold.The decision threshold T of QPSK and 8QAM is calculated1Are as follows:
Similarly, the decision threshold that can calculate 8QAM and 32QAM is T2The decision threshold of=0.5997,32QAM and 16QAM
For T3The decision threshold of=0.5719 and 16QAM and 64QAM is T4=0.4921.It should be noted that believing in OFDM-EON
When number actual transmissions, mould mean-square value can be by system spontaneous radiation (Amplified Spontaneous Emission, ASE) noise
Influence, generally according to signal with OSNR variation it is relatively steady when mould mean-square value, such as using system OSNR be 20dB when respectively adjust
The MMS value of format processed calculates decision threshold.
The corresponding average value of each number is compared by S103 with each decision threshold, true according to comparison result
The modulation format of the subcarrier of fixed each number.
Specifically, multiple threshold intervals can be determined according to all decision thresholds.The MMS for adjudicating each number subcarrier is average
Which threshold interval is value belong to.The modulation format of the subcarrier of each number is determined according to comparison result.
The MMS of identical number subcarrier is flat in X polarization and Y polarization of the embodiment of the present invention by calculating OFDM-EON system
Mean value MMSsub, and the decision threshold determined according to the MMS value of default modulation format, by MMSsubValue is carried out with decision threshold
Compare, identify the modulation format of each number subcarrier, to intelligence, identify quickly and steadily OFDM-EON system dynamic
The subcarrier-modulated format of variation, this method all have polarization mode dispersion, laser phase noise and frequency deviation stronger
Tolerance.
On the basis of the above embodiments, according to the MMS value of a variety of default modulation formats in the present embodiment, to various described
The step of default modulation format is ranked up includes: will be each according to the MMS value sequence from big to small of various default modulation formats
The default modulation format of kind is ranked up.
On the basis of the above embodiments, in the present embodiment by the average value of each corresponding number subcarrier with it is each described
The step of decision threshold is compared, and determines the modulation format of each number subcarrier according to comparison result specifically includes: pressing
According to each decision threshold putting in order from big to small, each decision threshold is ranked up, obtains any phase after sequence
The section that adjacent two decision thresholds are constituted；By the corresponding subcarrier MMS average value of each number according to each judgement
The sequence of threshold value is successively compared with each decision threshold, obtains out the section where the average value；By MMS value position
Default modulation format judgement where the average value in section is the modulation format of each number subcarrier.
Specifically, such as according to decision threshold T1、T2、T3And T45 not overlapped marked off according to sequence from big to small
A threshold interval specifically: be greater than or equal to T1Section is less than T1And it is greater than or equal to T2Section is less than T2And it is greater than or equal to T3
Section is less than T3And it is greater than or equal to T4Section is less than T4Section.To the MMS of two polarization subcarriers of same numbersubValue carries out
Judgement, if MMSsub≥T1, then determine the modulation format of the subcarrier for QPSK；If T2≤MMSsub< T1, then determine the subcarrier
Modulation format be 8QAM；If T3≤MMSsub< T2, then determine the modulation format of the subcarrier for 32QAM；If T4≤MMSsub<
T3, then determine the modulation format of the subcarrier for 16QAM；Otherwise determine the modulation format of the subcarrier for 64QAM.It is each in judgement
When which threshold interval the MMS average value of number subcarrier belong to, each decision threshold is arranged first in order to reduce calculation amount
Sequence is specifically ranked up, such as T by the sequence of each decision threshold from big to small1、T2、T3And T4.As shown in figure 3, by each number
The MMS of carrier wavesubIt is worth elder generation and T1It is compared, if MMSsub≥T1, then judge the modulation format of the subcarrier for QPSK, otherwise with
T2Compare；If MMSsub≥T2, then judge the modulation format of the subcarrier for 8QAM, otherwise with T3Compare；If MMSsub≥T3, then
Judge the modulation format of the subcarrier for 32QAM, otherwise with T4Compare；If MMSsub≥T4, then judge the modulation lattice of the subcarrier
Formula is 16QAM, and otherwise the modulation format of the subcarrier is 64QAM.Herein it should be noted that MMS value is located at where average value
Default modulation format in section only has one kind.For example: such as section [T2,T1) corresponding two adjacent thresholds are T2And T1,
T2It is determined by the MMS value of 8QAM and 32QAM, T1It is determined by the MMS value of QPSK and 8QAM, then MMS value is located at section [T2,T1)
Default modulation format only has 8QAM.For another example it is greater than or equal to T1Section in, T1It is determined by the MMS value of QPSK and 8QAM, this feelings
If the MMS of sub-carrier signal is located in the section under condition, corresponding default modulation format only has QPSK.
On the basis of the various embodiments described above, described in the present embodiment preset modulation format include QPSK, 8QAM, 16QAM,
32QAM and 64QAM.
The present embodiment is not limited to this five kinds of default modulation formats, and the modulation format of more high-order, the present embodiment can be used
It is not limited to the type and quantity of default modulation format.
On the basis of the various embodiments described above, each son in the X polarization and Y polarization of OFDM-EON system is calculated in the present embodiment
Before the step of MMS value of carrier wave further include: carried out to the signal of each subcarrier in the X polarization and Y polarization of OFDM-EON system
DSP flow processing；Wherein, the DSP flow processing includes sign synchronization, removal cyclic prefix, Fast Fourier Transform (FFT), polarization
Demultiplexing and channel equalization.
Specifically, it in the case where the subcarrier-modulated format of OFDM-EON system transmitting terminal randomly selects, docks first
The OFDM-EON signal received is equal by sign synchronization, removal cyclic prefix, Fast Fourier Transform (FFT), polarization demultiplexing and channel
The processing of the DSP flows such as weighing apparatus, then the identification of the modulation format of each subcarrier is carried out, to improve the standard of subcarrier-modulated format identification
True property.
For the validity for verifying above-described embodiment, OFDM-EON system as shown in Figure 4 has been built using Matlab and VPI
Sub-carriers modulation format identifies analogue system, and simulation parameter is as follows in detail: the bandwidth of OFDM-EON transmitting signal is
16GHz uses 256 subcarriers altogether, will 119 high frequency subcarriers therein filling, 0 realization over-sampling, and by central subcarrier
Zero setting is used for the offset estimation of receiving end, also uses 8 equally spaced pilot sub-carriers and realizes that phase noise restores, will be remaining
128 subcarriers transmit data-signal, each subcarrier is default this 5 kinds of { QPSK, 8QAM, 16QAM, 32QAM, 64QAM }
1 kind is randomly choosed in modulation format to be modulated；Every row subcarrier transmits 225 symbols altogether, wherein 4 training symbols are for inclined
Vibration demultiplexing and channel estimation, CP length are the 1/8 of symbol period；Laser linewidth is 100kHz, frequency deviation 100MHz；Optical fiber chain
The DGD (Differential Group Delay, Differential Group Delay) that pass enters be 65ps, OSNR variation range be 16dB~
27dB.It is carried out using the analog-digital converter (Analog-to-Digital Converter, ADC) of every channel 80GS/s sample rate
After coherent reception, then to the OFDM-EON signal that receives carry out resampling and normalization, sign synchronization and offset estimation, FFT,
The DSP such as channel equalization processing finally carries out corresponding modulation format identification verifying using the embodiment of the present invention.
It defines modulation format discrimination (Modulation Format Recognition Rate, MFRR) and measures the invention
Validity, calculation formula is as follows:
Wherein, NscRepresent number of subcarriers total in OFDM-EON system, NerrorAfter indicating modulated format identification, know
Not wrong number of subcarriers.
Fig. 5~Fig. 8 is set forth under different simulated conditions, and the MMS value of OFDM-EON sub-carrier signal is with system
The change curve of OSNR.MFRR is set forth under different simulated conditions with the change curve of OSNR in Fig. 9~10.
Firstly, we study the MMS value of every kind of modulation format with the variation tendency of OSNR.When OSNR is changed to from 16dB
When 27dB, acquired results are as shown in Figure 5 after calculating the MMS value of each subcarrier.As can be seen from Figure 5: with OSNR by
Cumulative big, the MMS curve of this 5 kinds of default modulation formats is gradually approached to respective theoretical value；Simultaneously according to illustration (a) in Fig. 5
Planisphere after channel equalization shown in~(e) it is also seen that, the included line width of laser and frequency deviation cause constellation point respectively
Diffusion and rotation, but it is little to the effect of radius of each annulus.Therefore, it is this based on MMS value modulation format identification have not by
The advantages of frequency deviation and line width influence can carry out before the recovery of each sub-carrier phase noise.
When carrying out subcarrier-modulated format identification, 22,50,107,221 are selected respectively in the data points of each subcarrier
And 449 in the case of this five kinds, corresponding to total amount of data is respectively 2816,6400,13696,28288 and 57472.When each son
When carrier wave is all made of 16QAM modulation, Fig. 6 gives the MMS value of every subcarrier with the change curve of OSNR.This it appears that:
The data points of each subcarrier are for the influence very little of signal MMS value, and the gap between each curve is 0.0076~0.0154
Within the scope of.Similarly, the MMS value of other modulation formats also meets this characteristic.I.e. the present invention carries out sub- load using MMS value
When wave modulation format identifies, do not influenced by the data points that every subcarrier participates in operation.
For OFDM-EON system, the presence of laser frequency deviation destroys the orthogonality between subcarrier, this will lead
Cause serious inter-carrier interference.When laser linewidth is fixed as 100kHz, DGD is set as 65ps, when other parameters are constant, OFDM-
EON system is respectively under 100MHz and 500MHz Frequency Offset, the change curve of MMS value when subcarrier uses different modulating format
As shown in Figure 7.It can be seen from the figure that with the increase of OSNR, the MMS curve co-insides under both frequency deviations together, therefore
Various lasers frequency deviation for different modulating format MMS value substantially without influence.
Since OFDM-EON system uses polarization multiplexing, it is investigated influence of the different DGD for MMS value.When
Laser linewidth is fixed as 100kHz, and when frequency deviation 100MHz, under the conditions of 2 kinds of DGD values, emulation obtains different modulating formatter load
The MMS value variation tendency of wave, acquired results are as shown in Figure 8.From figure it can be found that with DGD value increase, it is calculated
MMS value also slightly increases, and deviates with theoretical value farther.The reason of this phenomenon, is, uses 4 training symbols since system is fixed
Number polarization demultiplexing and channel estimation are carried out, it is poor for the channel equalization effect of larger DGD value, therefore corresponding MMS value is missed
Difference also increase with it, as long as but select suitable decision threshold, do not interfere with the blind recognition of modulation format.
Also analyze the influence that the data of every subcarrier are counted for this programme recognition success rate.When subcarrier uses at random
When QPSK or 8QAM is modulated, 221,449,904,1814 and 3634 data point calculation MMS values are respectively adopted to each subcarrier
And modulation format identification is carried out, acquired results are as shown in Figure 9.From figure it can be found that when OSNR is lower than 24dB, subcarrier
Data points are affected for MFRR, and the data points that subcarrier uses under same OSNR are more, and the calculating of MMS value is more accurate,
The MFRR of acquirement is higher, but corresponding calculation amount is bigger.In view of the equilibrium between computation complexity and MFRR, in following emulation
904 are taken with the data points of every subcarrier in experiment.
Figure 10 gives OFDM-EON system different modulating format subcarrier, carries out the blind knowledge of modulation format based on MMS value
Not after MFRR with OSNR change curve, Figure 11 be the corresponding error rate of system of Figure 10 (Bit Error Ratio, BER) with
The change curve of OSNR.Dotted line in Figure 11 indicates the forward error correction soft-decision door of the OFDM-EON system under different modulating format
It limits (Soft Decision-Forward Error Correction, SD-FEC).It can be seen that from Figure 10 and Figure 11 and work as system
When subcarrier uses the hybrid modulation of { QPSK, 8QAM } at random, although the embodiment of the present invention can be only achieved when OSNR is 20dB
100% recognition success rate, but when OSNR is 17dB, system can reach the thresholding of SD-FEC.Similarly, when subcarrier uses
When { QPSK, 16QAM } two kinds of format hybrid modulations, system can reach the thresholding of 7%FEC when OSNR is 19dB.Group carries
When wave uses { QPSK, 32QAM } two kinds of format hybrid modulations at random, system can reach the door of SD-FEC when OSNR is 23dB
Limit.Furthermore it is also found that when system subcarrier select at random set (QPSK, 64QAM), (8QAM, 64QAM), (QPSK,
8QAM, 64QAM) } in any one hybrid modulation when, system reach 7%FEC thresholding be 24dB.When system subcarrier with
Machine selects set { (16QAM, 64QAM), (32QAM, 64QAM), (QPSK, 32QAM, 64QAM), (QPSK, 16QAM, 64QAM) }
In any one hybrid modulation when, system reach 7%FEC thresholding be 25dB.
Effectiveness of the invention is described in further detail below in conjunction with OFDM-EON experiment Transmission system, structural frames
Figure is as shown in figure 12.The OFDM-EON radio frequency (RF) that total symbolic number is 206*128=26368 is generated first with MATLAB software
Signal, setting each subcarrier of OFDM-EON system modulation format combination dynamic, randomly set (QPSK, 8QAM),
(QPSK, 16QAM), (QPSK, 32QAM), (QPSK, 64QAM), (8QAM, 64QAM), (16QAM, 64QAM), (32QAM,
64QAM), (QPSK, 8QAM, 64QAM), (QPSK, 16QAM, 64QAM), (QPSK, 32QAM, 64QAM) } in select one kind,
Then remaining parameter of OFDM-EON will be led with the analogue system of above-mentioned Fig. 4 after described 4 times of OFDM-EON RF signal up-samplings
Enter in the arbitrary waveform generator (AWG) that sample rate is 65GS/s, recycles double IQ (PDM-IQ) modulator and external cavity lasers partially
Device (ECL) modulates the signal to area of light, and wherein the line width of ECL is about 100kHz, and central wavelength is set as 1550nm.To adjust system
The OSNR of system utilizes adjustable ASE noise source and optical attenuator VOA, after ASE noise is coupled with transmitting OFDM-EON signal, warp
It crosses EDFA amplification and is sent into optical filter to filter out optical noise.To filtered signal, we will using the optical splitter of a 90:10
It is divided into two-way, and all the way by spectroanalysis instrument observation signal spectrum, another way is input to the inclined of local oscillator laser (LO)
In vibration diversity coherent receiver.In receiving end, the high speed analog-to-digital conversion A/D of every channel 80GS/s is carried out to reception signal first,
Again by this acquisition signal by normalization, sign synchronization and offset estimation, removal cyclic prefix, Fast Fourier Transform (FFT), polarization
After the DSP flows processing such as demultiplexing and channel equalization, each sub- load of OFDM-EON system is finally gone out using intelligent recognition of the present invention
Wave modulation format.
In addition, under experimental conditions since the MMS value of different modulating format subcarrier will receive various system conditions, such as
The influence of OSNR, DGD and channel equalization effect.Therefore, in practical selected threshold boundary value, when selecting system OSNR as 20dB
The MMS value of different modulating format experimental data, acquires decision threshold are as follows:
According to decision threshold and flow chart shown in Fig. 3, to the MMS of same number subcarrier in the polarization of X, Y twosubBe worth into
Row determines, to identify modulation format used in all subcarriers in OFDM-EON system.Figure 13 and 14 is set forth
Under experimental conditions, the MMS value of OFDM-EON system reception signal is bent with the variation of OSNR with OSNR change curve and MFRR
Line.Experimental system frequency deviation be about 100MHz and optical fiber link in there are under conditions of 65ps DGD, obtained OFDM-EON connects
The MMS value of 5 kinds of modulation formats is as shown in figure 13 with OSNR change curve in the collection of letters number.It can be found that: under experimental conditions, with
The increase of OSNR, the MMS plots changes of 5 sub-carrier modulation formats and the simulation result of Fig. 5 are consistent substantially, this
The different modulating format for demonstrating OFDM-EON system subcarrier has the characteristic of different MMS values.
Figure 14, which is set forth, to test under simulated conditions, when selecting more modulation format at random, is based on the present invention in fact
Apply the success rate comparing result that example carries out OFDM-EON subcarrier-modulated format.We are herein with three kinds of typical hybrid modulations
It for { (QPSK, 8QAM), (16QAM, 64QAM), (QPSK, 32QAM, 64QAM) }, is can be found that from Figure 14: in experiment item
Under part, after carrying out subcarrier-modulated format blind recognition to the set of these three mixed modulation formats, for (QPSK, 8QAM) group
Close, the embodiment of the present invention OSNR be 20dB when MFRR up to 100%；(16QAM, 64QAM) is combined, the embodiment of the present invention
When OSNR is 27dB, MFRR is up to 100%；(QPSK, 32QAM, 64QAM) is combined, the embodiment of the present invention is in OSNR
MFRR is up to 100% when 29dB；Corresponding OSNR is respectively 19dB, 26dB and 27dB, experiment when accordingly reaching SD-FEC thresholding
As a result it coincide substantially with simulation result, demonstrates effectiveness of the invention.
A kind of OFDM-EON system sub-carriers modulation format identification device is provided in another embodiment of the present invention,
The device is for realizing the method in foregoing embodiments.Therefore, know in aforementioned OFDM-EON system sub-carriers modulation format
Description and definition in each embodiment of other method, can be used for explaining the effect of each execution module in the embodiment of the present invention.
Figure 15 is OFDM-EON system sub-carriers modulation format identification device overall structure diagram provided in an embodiment of the present invention, should
Device includes the first computing module 151, the second computing module 152 and determining module 153；Wherein:
First computing module 151 is used to calculate the MMS value of each subcarrier in the X polarization and Y polarization of OFDM-EON system, and
Calculate the MMS average value that the subcarrier of identical number is corresponded in the X polarization and Y polarization；
First computing module 151 is calculated according to the planisphere of each subcarrier in the X of OFDM-EON system polarization and Y polarization
The MMS value of each subcarrier.Assuming that the subcarrier of different numbers uses a variety of default modulation at random in the X polarization of OFDM-EON system
One of format, the subcarriers of different numbers use one of a variety of default modulation formats at random in Y polarization.In X polarization
The number of each subcarrier is different, and the number of each subcarrier is different in Y polarization, and the number and Y of X polarization sub-carriers are inclined
The number of center of percussion subcarrier corresponds to identical.The modulation format of the subcarrier of identical number is identical.It calculates and is compiled in X polarization and Y polarization
The MMS average value MMS of number identical subcarriersub, to reduce the influence of channel equalization performance.
Second computing module 152 is used for the MMS value according to a variety of default modulation formats, to the various default modulation formats
Sequence from big to small is carried out, using the MMS average value of two kinds of the arbitrary neighborhood default modulation formats after sequence as judgement threshold
Value；
In order to identify the modulation format of each subcarrier, need to choose decision threshold appropriate.Wherein, default modulation format is
Preset common modulation format in OFDM-EON system, the present embodiment are not limited to the classification and number of default modulation format.
Second computing module 152 calculates the MMS value of every kind of default modulation format according to the planisphere of various default modulation formats.According to
The MMS value of default modulation format is ranked up various default modulation formats.Two kinds of the arbitrary neighborhood default tune after sorting
The MMS average value of format processed is as decision threshold.
Determining module 153 is used to for the corresponding average value of each number being compared with each decision threshold, according to
Comparison result determines the modulation format of the subcarrier of each number.
Several sections not overlapped are marked off after each decision threshold is ranked up first, thereafter by each volume
Number corresponding subcarrier MMS average value is successively compared with each decision threshold according to the sequence of each decision threshold,
Stopping when ruling out this average value and being located at which section actually, is hereafter located in the decision threshold compared
In section, the modulation format in adjacent two kinds of default modulation formats with larger MMS value is adjudicated as each number
The modulation format of subcarrier.
For the embodiment of the present invention by calculating in OFDM-EON system, X polarizes identical number subcarrier corresponding with Y polarization
MMS average value MMSsub, decision threshold is determined according to the MMS value of default modulation format, by MMSsubValue is compared with decision threshold
Compared with the modulation format of each number subcarrier being identified, to intelligence, identify quickly and that steadily OFDM-EON system dynamic becomes
The subcarrier-modulated format of change, and stronger tolerance is all had for polarization mode dispersion, laser phase noise and frequency deviation.
On the basis of the above embodiments, the second computing module described in the present embodiment is specifically used for: according to various default
Various default modulation formats are ranked up by the sequence of the MMS value of modulation format from big to small.
On the basis of the above embodiments, determining module described in the present embodiment is specifically used for: according to each judgement threshold
Value putting in order from big to small, is ranked up each decision threshold, obtains any two neighboring judgement after sequence
The section that threshold value is constituted；By the corresponding average value of each number according to the sequence of each decision threshold, successively with it is each described
Decision threshold is compared, and obtains the section where the average value；It is pre- in section where MMS value is located at the average value
If modulation format, adjudicate as the modulation format of each number subcarrier.
On the basis of the various embodiments described above, described in the present embodiment preset modulation format include QPSK, 8QAM, 16QAM,
32QAM and 64QAM.
It further include processing module in the present embodiment on the basis of the various embodiments described above, for the X to OFDM-EON system
Each sub-carrier signal carries out DSP flow processing in polarization and Y polarization；Wherein, the DSP flow processing includes sign synchronization, goes
Except cyclic prefix, Fast Fourier Transform (FFT), polarization demultiplexing and channel equalization.
The present embodiment provides a kind of electronic equipment, Figure 16 is electronic equipment overall structure provided in an embodiment of the present invention signal
Figure, which includes: at least one processor 161, at least one processor 162 and bus 163；Wherein,
Processor 161 and memory 162 pass through bus 163 and complete mutual communication；
Memory 162 is stored with the program instruction that can be executed by processor 161, and the instruction of processor caller is able to carry out
Method provided by above-mentioned each method embodiment, for example, calculate each sub- load in the X polarization and Y polarization of OFDM-EON system
The MMS value of wave, and calculate the MMS average value that identical number subcarrier is corresponded in the X polarization and Y polarization；According to a variety of
The MMS value of default modulation format is ranked up the various default modulation formats, described pre- by two kinds of arbitrary neighborhood after sequence
If the MMS average value of modulation format is as decision threshold；By each corresponding MMS average value of number and each decision threshold
It is compared, the modulation format of the subcarrier of each number is determined according to comparison result.
The present embodiment provides a kind of non-transient computer readable storage medium, non-transient computer readable storage medium storages
Computer instruction, computer instruction make computer execute method provided by above-mentioned each method embodiment, for example, calculate
The MMS value of each subcarrier in the X polarization and Y polarization of OFDM-EON system, and calculate corresponding in the X polarization and Y polarization
The MMS average value of the subcarrier of identical number；According to the MMS value of a variety of default modulation formats to the various default modulation formats
It is ranked up, using the MMS average value of two kinds of the arbitrary neighborhood default modulation formats after sequence as decision threshold；It will be each described
It numbers corresponding MMS average value to be compared with each decision threshold, determines that the son of each number carries according to comparison result
Wave modulation format.
Those of ordinary skill in the art will appreciate that: realize that all or part of the steps of above method embodiment can pass through
The relevant hardware of program instruction is completed, and program above-mentioned can be stored in a computer readable storage medium, the program
When being executed, step including the steps of the foregoing method embodiments is executed；And storage medium above-mentioned includes: ROM, RAM, magnetic disk or light
The various media that can store program code such as disk.
The apparatus embodiments described above are merely exemplary, wherein described, unit can as illustrated by the separation member
It is physically separated with being or may not be, component shown as a unit may or may not be physics list
Member, it can it is in one place, or may be distributed over multiple network units.It can be selected according to the actual needs
In some or all of the modules achieve the purpose of the solution of this embodiment.Those of ordinary skill in the art are not paying creativeness
Labour in the case where, it can understand and implement.
Through the above description of the embodiments, those skilled in the art can be understood that each embodiment can
It realizes by means of software and necessary general hardware platform, naturally it is also possible to pass through hardware.Based on this understanding, on
Stating technical solution, substantially the part that contributes to existing technology can be embodied in the form of software products in other words, should
Computer software product may be stored in a computer readable storage medium, such as ROM/RAM, magnetic disk, CD, including several fingers
It enables and using so that a computer equipment (can be personal computer, server or the network equipment etc.) executes each implementation
Method described in certain parts of example or embodiment.
Finally, it should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention, rather than its limitations；Although
Present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that: it still may be used
To modify the technical solutions described in the foregoing embodiments or equivalent replacement of some of the technical features；
And these are modified or replaceed, technical solution of various embodiments of the present invention that it does not separate the essence of the corresponding technical solution spirit and
Range.
Claims (10)
1. a kind of OFDM-EON system sub-carriers modulation format recognition methods characterized by comprising
The MMS value of each subcarrier in the X polarization and Y polarization of OFDM-EON system is calculated, and calculates X polarization and the Y is inclined
Center of percussion corresponds to the MMS average value of the subcarrier of identical number；
The various default modulation formats are ranked up according to the MMS value of a variety of default modulation formats, by phase any after sequence
The MMS average value of adjacent two kinds of default modulation formats is as decision threshold；
Each MMS average value for numbering corresponding subcarrier is compared with each decision threshold, it is true according to comparison result
The modulation format of the subcarrier of fixed each number.
2. the method according to claim 1, wherein according to the MMS value of a variety of default modulation formats to various institutes
Stating the step of default modulation format is ranked up includes:
Various default modulation formats are ranked up according to the MMS value sequence from big to small of various default modulation formats.
3. according to the method described in claim 2, it is characterized in that, by each average value for numbering corresponding subcarrier and each institute
It states decision threshold to be compared, the specific steps for determining the modulation format of each number subcarrier according to comparison result include:
According to each decision threshold putting in order from big to small, each decision threshold is ranked up, after obtaining sequence
The section that arbitrary neighborhood two decision thresholds are constituted；
By the MMS average value of each number subcarrier according to the sequence of each decision threshold, successively with each judgement threshold
Value is compared, and obtains the section where the MMS average value；
Default modulation format where the MMS value of the number subcarrier is located at the average value in section is as each volume
The modulation format of sub-carriers.
4. method according to claim 1 to 3, which is characterized in that the default modulation format include QPSK, 8QAM,
16QAM, 32QAM and 64QAM.
5. method according to claim 1 to 3, which is characterized in that calculate the X polarization and Y polarization of OFDM-EON system
In each subcarrier MMS value the step of before further include:
DSP flow processing is carried out to the signal of each subcarrier in the X polarization and Y polarization of OFDM-EON system；Wherein, the DSP
Flow processing includes sign synchronization, removal cyclic prefix, Fast Fourier Transform (FFT), polarization demultiplexing and channel equalization.
6. a kind of OFDM-EON system sub-carriers modulation format identification device characterized by comprising
First computing module, the X for calculating OFDM-EON system polarizes the MMS value with each subcarrier in Y polarization, and calculates institute
State the MMS average value that the subcarrier of identical number is corresponded in X polarization and Y polarization；
Second computing module, for being arranged according to the MMS value of a variety of default modulation formats the various default modulation formats
Sequence, and using the MMS average value of two kinds of the arbitrary neighborhood default modulation formats after sequence as decision threshold；
Determining module, for each MMS average value for numbering corresponding subcarrier to be compared with each decision threshold, root
The modulation format of the subcarrier of each number is determined according to comparison result.
7. device according to claim 6, which is characterized in that second computing module is specifically used for:
Various default modulation formats are ranked up according to the MMS value sequence from big to small of various default modulation formats.
8. device according to claim 7, which is characterized in that the determining module is specifically used for:
According to each decision threshold putting in order from big to small, each decision threshold is ranked up, after obtaining sequence
The section that arbitrary neighborhood two decision thresholds are constituted；
By each MMS average value for numbering corresponding subcarrier according to the sequence of each decision threshold, successively described sentence with each
Certainly threshold value is compared, until comparison result is that each MMS average value for numbering corresponding subcarrier is described more than or equal to each
Decision threshold obtains the section where the average value；
Default modulation format where the MMS value of the number subcarrier is located at the average value in section, as each described
The modulation format of the subcarrier of number.
9. a kind of electronic equipment characterized by comprising
At least one processor, at least one processor and bus；Wherein,
The processor and memory complete mutual communication by the bus；
The memory is stored with the program instruction that can be executed by the processor, and the processor calls described program to instruct energy
Enough execute method as claimed in claim 1 to 5.
10. a kind of non-transient computer readable storage medium, which is characterized in that the non-transient computer readable storage medium is deposited
Computer instruction is stored up, the computer instruction makes the computer execute method as claimed in claim 1 to 5.
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