CN107257258B - The method that the random frequency deviation of laser influences is reduced in flexible grid elastic optical network - Google Patents
The method that the random frequency deviation of laser influences is reduced in flexible grid elastic optical network Download PDFInfo
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Abstract
The invention discloses a kind of methods that the random frequency deviation influence of laser is reduced in flexible grid elastic optical network, fixed frequency grid is divided into several fine-grained frequency grids first, then according to the sourcesink node of business, service traffics demand and current Internet resources, route symmetry is carried out for business, the frequency grid that need to guarantee that each sourcesink node is distributed in distribution is continuous, then the frequency interval of every group of cline frequency grid is compressed, frequency interval is compressed with two ways, one is the compressions of no spectrum overlapping, it can be received and be restored with conventional method, another kind is the compression there are spectrum overlapping, restored using butterfly balanced device.The present invention is compressed by the frequency interval to cline frequency grid, reduces influencing each other between the random frequency deviation of laser of different sourcesink nodes, improves the transmission performance of flexible grid elastic optical network.
Description
Technical field
The invention belongs to flexible grid elastic optical network technical fields, more specifically, are related to a kind of flexible grid bullet
Property optical-fiber network in reduce the method that the random frequency deviation of laser influences.
Background technique
As the development of broadband services needs optical-fiber network that can have super large appearance such as data center traffic, big data business
The features such as amount, dynamic flexible and service adaptation.(Wavelength Division Multiplexing, wavelength-division are multiple by traditional WDM
With) system limited by fixed-grid, so that network optical wavelength utilization rate is low, optical channel lacks flexibility, optical signal is not clever enough
It is living, it is not able to satisfy the network Development demand of the following service-oriented driving.In order to overcome the above problems, it may be considered that by fixed-grid
Spectral bandwidth be further divided into more fine-grained flexible grid, relative to the spectrum intervals of traditional fixed-grid, fine granularity
Wavelet length can be in a network its frequency slot for distributing corresponding number by actual traffic needs sizes dynamic, to realize net
The distribution according to need of network resource.Currently, thin frequency spectrum granularity, the flexible grid elastic optical network of high spectrum utilization have become the following light
The development trend of network technology.
It is more tiny by the way that the frequency grid of 50GHz to be divided into the flexible grid elastic optical network under current standard
Spectrum unit (such as frequency band of 12.5GHz bandwidth) wavelet length signal, the spectrum utilization efficiency of optical-fiber network can be improved.But
It is that in practical applications, due to the presence of the influences such as variation of ambient temperature, the laser of optical network node can inevitably go out
The drift of existing wavelength or frequency, so that the frequency interval of adjacent wavelet length optical signal be caused to change.In ITU.T-WDM standard
In, the wdm system for being 50GHz for channel spacing, permission filters center frequency deviation range is positive and negative 2.5GHz.Fig. 1 is
The random frequency deviation of laser causes signal spectrum to partly overlap schematic diagram.As shown in Figure 1, the frequency deviation of positive and negative 2.5GHz is for traditional
It may influence for the wavelength interval of 50GHz less, it is possible that the wavelet length system to thinner frequency grid brings ICI
(Inter Carrier Interference, inter-carrier interference).
Fig. 2 is that occur the error performance emulation that signal transmits when different random frequency deviation sizes between the long optical signal of adjacent wavelet
Result figure.The wavelength interval of traditional 50GHz is evenly divided into the frequency interval of 4 12.5GHz, every height in emulation
The transmission character rate of wavelength channels is set as 7GHz.As shown in Fig. 2, working as the corresponding laser of adjacent two-way wavelet length signal
Between when there is random frequency deviation, may cause the spectrum overlapping between two-way wavelet length signal and ICI interference occur, lead to transmission performance
Deterioration.By simulation result it is found that when random frequency deviation is larger, spectrum overlapping is more serious between the long optical signal of adjacent wavelet, leads
The transmission performance for the number of writing is deteriorated.
Fig. 3 is different frequencies small error performance simulation result diagram bigger than normal under different wavelet Long grains.It will be passed respectively in emulation
The wavelength interval of the 50GHz of system is evenly divided into 1/2/4/8 wavelet length frequency band, and transmission signal is 4QAM (Quadrature
Amplitude Modulation, quadrature amplitude modulation) signal, the root raised cosine signal (Root for the use of rolloff-factor being 0.5
Raised Cosine, RRC) carry out frequency spectrum shaping.As shown in figure 3, when transmitting 1 tunnel or 2 way wavelength signals, due to wavelet
Long interval is larger, therefore laser bring random offset does not have much affect to Transmission system.But with the increasing of wavelet length number
Add, grid spacings become smaller, and the lap between different wavelet length signals may become larger with laser frequency deviation, performance gradually under
Drop.Particularly, for frequency grid be 6.25GHz 8 way wavelength when, the random frequency deviation of laser bring makes the property of signal
Can sharply it deteriorate.
In optical-fiber network, routing and the distribution of frequency grid are carried out between the business a certain sourcesink node.Traditional
The distribution method of frequency grid mainly has 2 kinds: a kind of distribution method is distributed as far as possible for the business of the same sourcesink node of correspondence
Cline frequency grid, the multiple cline frequency grids at this moment distributed are taken as a super channel to swap and route, therefore with
Machine frequency deviation only will affect the grid at edge, and signal is influenced smaller by random frequency deviation, but be easy to produce in the distribution of this frequency spectrum resource
Raw frequency spectrum fragment, thus cause the waste of frequency spectrum resource and frequency grid distribute it is not flexible；Another division methods are to frequency
Grid carries out independent, fine-grained distribution, i.e., the fixed frequency grid of 50GHz is divided into multiple fine-grained frequencies first
Grid is supported to transmit fine-grained wavelet length signal, while the change of business modulation format may be implemented, more preferable to realize business
Match and flexible transmission improve the overall performance index of network while improving the availability of frequency spectrum, come adapt to the following large capacity,
High efficiency, the transmission demand of low energy consumption, but the random frequency deviation of laser to it is this it is independent, fine-grained effect of signals is brighter
It is aobvious.
Summary of the invention
It is an object of the invention to overcome the deficiencies of the prior art and provide reduce to swash in a kind of flexible grid elastic optical network
The method that the random frequency deviation of light device influences, introduces the frequency interval compression side of cline frequency grid on the basis of respectively frequency grid
Method reduces influencing each other between the random frequency deviation of laser of different sourcesink nodes, improves the transmission of flexible grid elastic optical network
Performance.
For achieving the above object, reduce what the random frequency deviation of laser influenced in flexible grid elastic optical network of the present invention
The specific steps of method include:
S1: fixed frequency grid is divided into several fine-grained frequency grids, obtains the initial of each frequency grid
Channelized frequencies；
S2: according to the sourcesink node of business, service traffics demand and current Internet resources, for business carry out routing and
Wavelength Assignment, the frequency grid that same sourcesink node is distributed are continuous, the corresponding one group of cline frequency grid of each sourcesink node
Lattice；
S3: for every group of cline frequency grid, according to the initial multiplexing of the quantity of its frequency grid and each frequency grid
Frequency determines the centre frequency of this group of cline frequency grid, according to the bandwidth of each frequency grid the centre frequency two sides again
Each frequency grid, the actual frequency interval of side frequency grid are setValue range be [B, F), wherein B indicate son carry
The bandwidth of wave signal, F indicate the frequency interval of initial channelized frequencies, obtain each frequency grid in this group of cline frequency grid
Practical channelized frequenciesAfter determining practical channelized frequencies, transmitting terminal and receiving end are sent relevant information to；
S4: the subcarrier multiplex frequency signal of each frequency grid of transmitting terminal electrical domain；
S5: each baseband signal is modulated to obtain subcarrier letter with corresponding subcarrier multiplex frequency signal by transmitting terminal
Number, each sub-carrier signal is multiplexed, optical signal is then converted to and is sent；
S6: receiving end is changed into electric signal after receiving optical signal, realizes each sub-carrier signal point according to practical channelized frequencies
From, and restore to obtain baseband signal.
The present invention also provides the method for reducing the random frequency deviation of laser in another flexible grid elastic optical network and influencing,
Specific steps are as follows:
S1: fixed frequency grid is divided into several fine-grained frequency grids, obtains the initial of each frequency grid
Channelized frequencies；
S2: according to the sourcesink node of business, service traffics demand and current Internet resources, for business carry out routing and
Wavelength Assignment, the frequency grid that same sourcesink node is distributed are continuous, the corresponding one group of cline frequency grid of each sourcesink node
Lattice；
S3: for every group of cline frequency grid, according to the initial multiplexing of the quantity of its frequency grid and each frequency grid
Frequency determines the centre frequency of this group of cline frequency grid, according to the bandwidth of each frequency grid the centre frequency two sides again
Each frequency grid, the actual frequency interval of side frequency grid are setValue range be [B- δ, B), wherein B indicate frequency
The bandwidth of rate grid, δ indicate deviant, obtain the practical channelized frequencies of each frequency grid in this group of cline frequency grid
After determining practical channelized frequencies, transmitting terminal and receiving end are sent relevant information to；
S4: the subcarrier multiplex frequency signal of each frequency grid of transmitting terminal electrical domain；
S5: each baseband signal is modulated to obtain subcarrier letter with corresponding subcarrier multiplex frequency signal by transmitting terminal
Number, each sub-carrier signal is multiplexed, optical signal is then converted to and is sent；
S6: receiving end is changed into electric signal after receiving optical signal, realizes each sub-carrier signal point according to practical channelized frequencies
From, realize that baseband signal is restored using butterfly balanced device, method particularly includes:
Configure a butterfly balanced device for each sub-carrier signal, each butterfly equalizer setting there are three sub- balanced device,
For n-th isolated of sub-carrier signal, n=1,2 ..., N, N indicates the quantity of frequency grid in cline frequency grid,
Itself and two adjacent sub-carrier signals (i.e. (n-1)th, n-th and (n+1)th sub-carrier signal) are inputted into butterfly respectively
Equilibrium is carried out in three sub- balanced devices of shape balanced device, and cascading judgement then is carried out to balanced three obtained signal, is restored
To the baseband signal of n-th of sub-carrier signal.
The method that the random frequency deviation of laser influences is reduced in flexible grid elastic optical network of the present invention, first by fixed frequency
Grid is divided into several fine-grained frequency grids, then according to the sourcesink node of business, service traffics demand and current
Internet resources, carry out route symmetry for business, need to guarantee the frequency grid that each sourcesink node distributed in distribution
Lattice be it is continuous, then the frequency interval of every group of cline frequency grid is compressed, frequency interval is compressed with two ways, one
Kind is the compression of no spectrum overlapping, and conventional method can be used to receive and restore, and another kind is the compression there are spectrum overlapping, is used
Butterfly balanced device restores.The present invention is compressed by the frequency interval to cline frequency grid, reduces identical sources destination node
Frequency interval between sub-carrier signal increases the frequency interval between the sub-carrier signal of non-equal sourcesink node, to reduce
Influencing each other between the random frequency deviation of laser of different sourcesink nodes improves the transmission performance of flexible grid elastic optical network.
Detailed description of the invention
Fig. 1 is that the random frequency deviation of laser causes signal spectrum to partly overlap schematic diagram；
Fig. 2 is that occur the error performance emulation that signal transmits when different random frequency deviation sizes between the long optical signal of adjacent wavelet
Result figure；
Fig. 3 is different frequencies small error performance simulation result diagram bigger than normal under different wavelet Long grains；
Fig. 4 is the first tool that the method that the random frequency deviation of laser influences is reduced in flexible grid elastic optical network of the present invention
Body embodiment flow chart；
Fig. 5 is the frequency interval compression exemplary diagram of cline frequency grid；
Fig. 6 is centre frequency and frequency grid exemplary diagram under six kinds of different situations；
Fig. 7 is the error performance comparison of the frequency interval compression front and back of first method cline frequency grid in the present embodiment
Figure；
Fig. 8 is the error performance comparison diagram of the frequency interval compression front and back of cline frequency grid under distinct symbols rate；
Fig. 9 is second of tool that the method that the random frequency deviation of laser influences is reduced in flexible grid elastic optical network of the present invention
Body embodiment flow chart；
Figure 10 is the exemplary diagram that the recovery of cline frequency grid sub-carrier signal is realized based on butterfly balanced device；
Figure 11 is the structure chart of the sub- balanced device of butterfly balanced device in the present embodiment；
Figure 12 is the compressed error performance emulation of frequency interval of second method cline frequency grid in the present embodiment
Result figure.
Specific embodiment
A specific embodiment of the invention is described with reference to the accompanying drawing, preferably so as to those skilled in the art
Understand the present invention.Requiring particular attention is that in the following description, when known function and the detailed description of design perhaps
When can desalinate main contents of the invention, these descriptions will be ignored herein.
Embodiment
Fig. 4 is the first tool that the method that the random frequency deviation of laser influences is reduced in flexible grid elastic optical network of the present invention
Body embodiment flow chart.As shown in figure 4, reducing what the random frequency deviation of laser influenced in flexible grid elastic optical network of the present invention
The specific steps of method include:
S401: frequency grid divides:
Fixed frequency grid is divided into several fine-grained frequency grids, obtains the initial multiplexing of each frequency grid
Frequency, it is specific divide parameter, that is, fine-grained frequency grid quantity, it determines according to actual needs.
S402: route symmetry:
According to the sourcesink node of business, service traffics demand and current Internet resources, routing and wave are carried out for business
Long distribution, the frequency grid that same sourcesink node is distributed are continuous, the corresponding one group of cline frequency grids of each sourcesink node.
Number and the position for thereby determining that the grid of business, since the route symmetry of optical network resource is the existing skill of this field
Art, and be not the description emphasis of technical scheme, this will not be repeated here.
S403: the compression of cline frequency frequency grid interval:
For every group of cline frequency grid, according to the initial multiplexing of the quantity of its frequency grid and each frequency grid frequency
Rate determines the centre frequency of this group of cline frequency grid, is set again according to the bandwidth of each frequency grid in the centre frequency two sides
Set each frequency grid, the actual frequency interval of side frequency gridValue range be [B, F), wherein B indicate subcarrier
The bandwidth of signal, F indicate the frequency interval of initial channelized frequencies, obtain the reality of each frequency grid in this group of cline frequency grid
Border channelized frequenciesIt can be seen that the method for the present invention is to reduce the frequency of side frequency grid by resetting cline frequency grid
Interval, to realize the frequency interval compression of cline frequency grid.After determining practical channelized frequencies, need relevant information
It is sent to transmitting terminal and receiving end.
Step S401 to step S403 can be completed in transmitting terminal or be completed in special administrative center, be generally selected
It is completed in transmitting terminal.
By taking traditional 50GHz frequency grid is divided into the frequency grid of 4 uniform 12.5GHz as an example, to cline frequency
The frequency interval compression of grid is specifically described, and practical frequency interval is compressed into sub-carrier signal amount of bandwidth, i.e.,Fig. 5 is the frequency interval compression exemplary diagram of cline frequency grid.Wherein Fig. 5 (a) is that original frequency grid division is shown
Example diagram is divided into the frequency grid of 4 12.5GHz that is, in original frequency grid division.Fig. 5 (b) is two cline frequency grid
Lattice compress exemplary diagram, and as shown in Fig. 5 (b), leftmost two are assigned to identical source in the frequency grid of 4 12.5GHz
Destination node.Fig. 5 (c) is three cline frequency grid compression exemplary diagrams, as shown in Fig. 5 (c), in the frequency grid of 4 12.5GHz
Leftmost three are assigned to identical sourcesink node.Fig. 5 (d) is four cline frequency grids compression exemplary diagrams, i.e., 4
The frequency grid of 12.5GHz is all allocated to identical sourcesink node.
When determining the centre frequency of every group of cline frequency grid and resetting frequency grid, it can according to need and set
Specific method is set, uses following methods in the present embodiment: remembering that certain organizes the quantity of frequency grid in cline frequency grid for N, often
The initial channelized frequencies of a frequency grid is fn, n=1,2 ..., N, bandwidth B, then this group of cline frequency is in general arranged
The centre frequency f of gridc=(f1+fN)/2, the practical channelized frequencies of n-th of frequency grid
The frequency interval of each frequency grid is uniform in every group of cline frequency grid that this method obtains.
Similarly, illustrate this reality so that 50GHz frequency grid is divided into the frequency grid of 4 uniform 12.5GHz as an example
The setting method of centre frequency and frequency grid in example is applied, actual frequency interval is set hereinFig. 6 is six kinds and does not sympathize with
Centre frequency and frequency grid exemplary diagram under condition.As shown in fig. 6, the quantity that frequency grid in cline frequency grid is respectively set is
2,3,4.In original frequency grid division, the initial channelized frequencies of the frequency grid of each 12.5GHz is relative to 50GHz frequency
The deviant of the centre frequency of grid is respectively -18.75, -6.25,6.25,18.75.For simplicity description, made below with deviant
It is calculated for frequency values.By taking Fig. 6 (d) as an example, 3 frequency grids in cline frequency grid are Far Left 3, initial to be multiplexed
Frequency is respectively -18.75, -6.25,6.25, then the centre frequency f of this group of cline frequency gridc=(- 18.75+6.25)/2
=-6.25, and actual frequency interval is equal to sub-carrier signal bandwidth B, therefore 3 frequency grids in this group of cline frequency grid
The deviant of practical channelized frequencies is respectively The detailed process of other five kinds of situations is similar, and details are not described herein.
S404: electrical domain channelized frequencies signal:
The subcarrier multiplex frequency signal of each frequency grid of transmitting terminal electrical domain generates each subcarrier multiplex frequency in electrical domain
Rate signal exp (j2 π fkT), wherein fkIt is the corresponding channelized frequencies of subcarrier of k-th of frequency grid, k=1,2 ..., K, K table
Show that the sum of frequency grid, j are imaginary symbols, t indicates the time.The present embodiment is when realizing, using exp (j2 π fkT)=cos
(j2πfkt)+jsin(j2πfkT), the specific implementation of sin and cos can be completed by the way of look-up table.
S405: signal modulation and multiplexing are sent:
Each baseband signal is modulated to obtain sub-carrier signal by transmitting terminal with corresponding subcarrier multiplex frequency signal,
The process can be considered as frequency spectrum shift, then modulated k-th of sub-carrier signal Sk(t)=Ik(t)×exp(j2πfkT), Ik
(t) indicate that multiplier realization can be used in k-th of baseband signal, the process.Each sub-carrier signal is multiplexed, is then turned
It turns to optical signal to be sent, multiplexed signals S (t) can be expressed as
Adder realization can be used in the process.
S406: signal receives and restores:
Receiving end is changed into electric signal after receiving optical signal, realizes that each sub-carrier signal separates according to practical channelized frequencies,
And restore to obtain baseband signal.The process is the state of the art, and details are not described herein for detailed process.
According to above step it is found that flexible grid elastic optical network first respectively obtains fine granularity in the usual way in the present invention
Then frequency grid resets each frequency grid subcarrier multiplex frequency in cline frequency grid, since electrical domain number is believed
Number processing technique have been relatively mature, and the channelized frequencies of each sub-carrier signal can accurately be controlled, to realize wavelet length signal
The compression of frequency interval, the frequency interval between the sub-carrier signal of identical sources destination node suitably becomes smaller, rather than identical sources destination node
Sub-carrier signal between frequency interval then can accordingly become larger, between the random frequency deviation of laser for advantageously reducing different sourcesink nodes
Influence each other.
The technical effect of method in order to better illustrate the present invention carries out the transmission performance of frequency interval compression front and back
Emulation.50GHz frequency grid is still divided into the frequency grid of 4 uniform 12.5GHz, and by this 4 in this emulation
Frequency grid is allocated to same sourcesink node, i.e. 4 frequency grids constitute one group of cline frequency grid, is believed using RRC pulse
Number as modulation pulse.RRC pulse signal is a kind of limited signal of bandwidth, and amount of bandwidth depends on roll-offing for pulse signal
Factor-beta, the bandwidth of RRC pulse signal are (1+ β) RS, wherein RSIt is the symbol transmission rate of system.It will be apparent that using RRC
In the system of pulse signal, symbol transmission rate is higher, and the bandwidth of signal is higher, therefore the influence of the random frequency deviation of laser is also got over
Seriously.The symbol transmission rate of this emulation setting wavelet length signal is 7GHz, and the roll-off factor of RRC pulse signal is 0.5, can
The bandwidth for knowing the signal is 10.5GHz.The random frequency deviation of no laser ideally, the frequency grid of 12.5GHz is energy
Enough carry the wavelet length signal that bandwidth is 10.5GHz.But if when laser is there are when the random frequency deviation of 2.5GHz, it is right
The wavelet length signal answered can deviate therewith, thus beyond the frequency grid of oneself is distributed to, and neighbouring wavelet length signal is made
At interference.It will be apparent that symbol transmission rate is higher, roll-off factor is bigger, and the bandwidth that signal needs is bigger, the random frequency of stimulated light device
Inclined influence also can be more serious.
Fig. 7 is the error performance comparison of the frequency interval compression front and back of first method cline frequency grid in the present embodiment
Figure.As shown in fig. 7, the 4 way wavelength for being 7GHz for character rate, the fixed-grid of 50GHz become the wavelet length of 12.5GHz
Signal, wavelet length frequency grid boil down to 10.5GHz.After frequency interval is compressed as can be seen from Figure 7, the error performance of system
Compared with having promotion before frequency interval compression, this is because the edge subcarrier spacing of different sourcesink nodes becomes larger, can be effectively reduced
The influence of the random frequency deviation of laser bring, 4 way wavelength signals when compared to unused frequency compression, performance improve about 1dB.
Fig. 8 is the error performance comparison diagram of the frequency interval compression front and back of cline frequency grid under distinct symbols rate.Such as
Shown in Fig. 8, character rate is respectively increased 7.5GHz, when 8GHz, the roll-off factor of RRC remains as 0.5, wavelet length frequency grid
The frequency interval of lattice distinguishes boil down to 11.25GHz, 12GHz.It can be seen that with the increase of character rate, the bandwidth of signal adds
Greatly, when random frequency deviation occurs for laser, lap is increased between wavelet length, and signal errors performance is caused to be gradually reduced.And make
After being compressed with frequency interval, the edge subcarrier spacing of different sourcesink nodes becomes larger, and random frequency deviation influence becomes smaller, signal errors
It can improve.
It is reduced in foregoing flexible grid elastic optical network in the method that the random frequency deviation of laser influences, it is desirable that phase
The actual frequency interval of adjacent frequency gridValue range be [B, F), i.e., mutually do not occur frequency spectrum weight between sub-carrier signal
It, can be between frequency when folding, and further increasing the transmission rate of system if necessary and need using higher signal bandwidth
Every further being compressed, it will appear certain spectrum overlapping and ICI between adjacent sub-carrier signal at this time.In order to solve this
One problem, the present invention also provides the method for reducing the random frequency deviation of laser in another flexible grid elastic optical network and influencing,
Realize the reception and recovery of cline frequency grid sub-carrier signal, based on butterfly balanced device to reduce the influence of ICI.
Fig. 9 is second of tool that the method that the random frequency deviation of laser influences is reduced in flexible grid elastic optical network of the present invention
Body embodiment flow chart.As shown in figure 9, reducing what the random frequency deviation of laser influenced in flexible grid elastic optical network of the present invention
The specific steps of method include:
S901: frequency grid divides:
Fixed frequency grid is divided into several fine-grained frequency grids, obtains the initial multiplexing of each frequency grid
Frequency.
S902: route symmetry:
According to the sourcesink node of business, service traffics demand and current Internet resources, routing and wave are carried out for business
Long distribution, the frequency grid that same sourcesink node is distributed are continuous, the corresponding one group of cline frequency grids of each sourcesink node.
S903: there are the compressions of the cline frequency frequency grid interval of spectrum overlapping:
For every group of cline frequency grid, according to the initial multiplexing of the quantity of its frequency grid and each frequency grid frequency
Rate determines the centre frequency of every group of cline frequency grid, is set again according to the bandwidth of each frequency grid in the centre frequency two sides
Set each frequency grid, the actual frequency interval of side frequency gridValue range be [B- δ, B), wherein B indicate son carry
The bandwidth of wave signal, δ indicate deviant, obtain the practical channelized frequencies of each frequency grid in this group of cline frequency grid
After determining practical channelized frequencies, transmitting terminal and receiving end are sent relevant information to.Deviant δ is for controlling subcarrier letter
Between number frequency be overlapped degree size, be to be arranged according to the concrete condition of real system, when system overall transfer performance compared with
It when good, can suitably increase its value, when system overall transfer performance is poor, can reduce its value, to reduce the influence of ICI.
In practice, it can be tested after system building is good and obtain the maximum value of deviant δ, for using.
S904: electrical domain channelized frequencies signal:
The subcarrier multiplex frequency signal of each frequency grid of transmitting terminal electrical domain generates each subcarrier multiplex frequency in electrical domain
Rate signal.
S905: signal modulation and multiplexing are sent:
Each baseband signal is modulated to obtain sub-carrier signal with corresponding subcarrier multiplex frequency signal.
S906: signal receives and restores:
Receiving end is changed into electric signal after receiving optical signal, realizes that each sub-carrier signal separates according to practical channelized frequencies,
And restore to obtain baseband signal.In the present invention, due to adjacent son in cline frequency grid after frequency interval compression in step S903
Carrier signal will appear spectrum overlapping, therefore realize that baseband signal is restored using butterfly balanced device, method particularly includes:
Configure a butterfly balanced device for each sub-carrier signal, each butterfly equalizer setting there are three sub- balanced device,
For n-th isolated of sub-carrier signal, n=1,2 ..., N, N indicates the quantity of frequency grid in cline frequency grid,
Itself and two adjacent sub-carrier signals (i.e. (n-1)th, n-th and (n+1)th sub-carrier signal) are inputted into butterfly respectively
Equilibrium is carried out in three sub- balanced devices of shape balanced device, and cascading judgement then is carried out to balanced three obtained signal, is restored
To the baseband signal of n-th of sub-carrier signal.It will be apparent that for the sub-carrier signal at cline frequency grid both ends, due to only
There is adjacent sub-carrier signal in side, therefore in three sub- balanced devices of corresponding butterfly balanced device, only deposits there are two balanced device
It is inputted in sub-carrier signal, the input of a remaining sub- balanced device is 0.
Figure 10 is the exemplary diagram that the recovery of cline frequency grid sub-carrier signal is realized based on butterfly balanced device.Such as Figure 10 institute
Show, by taking continuous 4 sub-carrier signals as an example, each sub-carrier signal is carried out first, in accordance with the practical channelized frequencies of each subcarrier
Preliminary digital filtering separates, and the frequency spectrum of 4 sub-carrier signals after initial gross separation is also given in Figure 10.It will be apparent that each
The interference of other adjacent sub-carrier signals is all contained in sub-carrier signal.Then it is balanced butterfly to be carried out to each sub-carrier signal.
By taking sub-carrier signal B as an example, in 4 signal spectrums that initial gross separation obtains, other than frequency spectrum B, neighbouring sub-carrier signal A
It also all include the influence of sub-carrier signal B with C, therefore in order to restore the baseband signal of sub-carrier signal B, butterfly balanced device will
Using these three signals as input, the equilibrium of Lai Shixian sub-carrier signal B, i.e., by isolated sub-carrier signal A, B, C
Sub- balanced device h is inputted respectivelyAB、hBB、hBCIn, cascading judgement then is carried out to balanced three obtained signal, obtains subcarrier
The baseband signal of signal B.
In the present embodiment, the sub- balanced device of butterfly balanced device is realized using linear transverse filter.Figure 11 is the present embodiment
The structure chart of the sub- balanced device of middle butterfly balanced device.Z in figure-1Indicate time delay.As shown in figure 11, linear transverse filter is at the moment
The output signal of kExpression formula are as follows:
Wherein, L is the number parameter of the tap gain coefficient of linear transverse filter, that is, has 2L+1 tap gain system
Number, ClIndicate first of tap gain coefficient, l=-L ..., L, rk-lIndicate tap gain coefficient ClIt is corresponding receive signal when
Extension signal.
Tap gain adjustment algorithm is used to adaptively adjust tap gain coefficient, tap gain system according to system actual conditions
Number is adjusted according to the error signal of sub-carrier signal, error signalkCalculation formula:
Wherein,The decision signal for indicating moment k, i.e., according to output signalObtained decision signal.
The adjustment formula of the tap gain coefficient of linear transverse filter is as follows:
Wherein, the vector that 2L+1 tap gain coefficient when C [k] and C [k+1] respectively indicates moment k, moment k+1 is constituted,
λ is iteration step length, rkIt indicates to participate inThe vector of the delay time signal composition of 2L+1 reception signal of calculating.
According to above formula it is found that the calculating of either equalizer output signal or the iteration meter of tap gain coefficient
It calculates, is completed by the multiplication of plural number and add operation.
The technical effect of second method in order to better illustrate the present invention, the equally transmission to frequency interval compression front and back
Performance is emulated.Similarly, 50GHz frequency grid is still divided into the frequency of 4 uniform 12.5GHz in this emulation
Rate grid, and this 4 frequency grids are allocated to same sourcesink node, i.e. 4 frequency grids constitute one group of cline frequency grid
Lattice, using RRC pulse signal as modulation pulse.The symbol transmission rate of this emulation setting wavelet length signal is 7GHz, RRC
The roll-off factor of pulse signal is 0.5, it is known that the bandwidth of the signal is 10.5GHz.
Figure 12 is the compressed error performance emulation of frequency interval of second method cline frequency grid in the present embodiment
Result figure.As shown in figure 12, for 4 way wavelength signals after Spectrum compression and butterfly are balanced, it can be seen that the property of signal
Can be close to theoretical value, the case where 4 way wavelength signals compared to Fig. 3 (c) in Fig. 3 do not carry out frequency interval compression, error performance
Have and is obviously improved.
In conclusion the present invention provides reduce what the random frequency deviation of laser influenced in two kinds of flexible grid elastic optical networks
Method.In flexible grid elastic optical network, different optical paths can also use the height of distance adaptation according to sourcesink node location
It imitates frequency spectrum and distributes different number of wavelet length.In long distance transmission, the noise of signal is relatively low, the ICI interference that can be tolerated
It is lower, therefore the influence of possible random frequency deviation can be reduced using the method for the present invention.It can not only be saved using the present invention
The frequency spectrum resource of network improves frequency spectrum resource utilization rate, also can effectively reduce the blocking rate of network, given full play to flexible grid
The flexibility and high efficiency feature of elastic optical network.In short-distance transmission, because the noise of signal is relatively high, can tolerate
ICI interference is larger, therefore those the discontinuous frequency spectrum of frequency band grid " fragment " wavelet length signals can be made full use of to be transmitted,
To improve the frequency spectrum service efficiency of optical-fiber network, the flexible configuration of network is realized.
Although the illustrative specific embodiment of the present invention is described above, in order to the technology of the art
Personnel understand the present invention, it should be apparent that the present invention is not limited to the range of specific embodiment, to the common skill of the art
For art personnel, if various change the attached claims limit and determine the spirit and scope of the present invention in, these
Variation is it will be apparent that all utilize the innovation and creation of present inventive concept in the column of protection.
Claims (5)
1. reducing the method that the random frequency deviation of laser influences in a kind of flexible grid elastic optical network, it is characterised in that including following
Step:
S1: fixed frequency grid is divided into several fine-grained frequency grids, obtains the initial multiplexing of each frequency grid
Frequency；
S2: according to the sourcesink node of business, service traffics demand and current Internet resources, routing and wavelength are carried out for business
Distribution, the frequency grid that same sourcesink node is distributed are continuous, the corresponding one group of cline frequency grids of each sourcesink node；
S3: for every group of cline frequency grid, according to the initial channelized frequencies of the quantity of its frequency grid and each frequency grid,
The centre frequency for determining this group of cline frequency grid is reset respectively according to the bandwidth of each frequency grid in the centre frequency two sides
A frequency grid, the actual frequency interval of side frequency gridValue range be [B, F), wherein B indicate sub-carrier signal
Bandwidth, F indicates the frequency interval of initial channelized frequencies, and the reality for obtaining each frequency grid in this group of cline frequency grid is multiple
Use frequencyAfter determining practical channelized frequencies, transmitting terminal and receiving end are sent relevant information to；
S4: transmitting terminal generates the subcarrier multiplex frequency signal of each frequency grid in electrical domain；
S5: each baseband signal is modulated to obtain sub-carrier signal by transmitting terminal with corresponding subcarrier multiplex frequency signal,
Each sub-carrier signal is multiplexed, optical signal is then converted to and is sent；
S6: receiving end is changed into electric signal after receiving optical signal, realizes that each sub-carrier signal separates according to practical channelized frequencies, and
Recovery obtains baseband signal.
2. the method according to claim 1 for reducing the random frequency deviation of laser and influencing, which is characterized in that in the step S3
The centre frequency of every group of cline frequency grid is determining and resets frequency grid method particularly includes:
The quantity for remembering frequency grid in certain group cline frequency grid is N, and the initial channelized frequencies of each frequency grid is fn, n=1,
The centre frequency f of this group of cline frequency grid is arranged in 2 ..., N, bandwidth Bc=(f1+fN)/2, the reality of n-th of frequency grid
Channelized frequencies
3. reducing the method that the random frequency deviation of laser influences in a kind of flexible grid elastic optical network, it is characterised in that including following
Step:
S1: fixed frequency grid is divided into several fine-grained frequency grids, obtains the initial multiplexing of each frequency grid
Frequency；
S2: according to the sourcesink node of business, service traffics demand and current Internet resources, routing and wavelength are carried out for business
Distribution, the frequency grid that same sourcesink node is distributed are continuous, the corresponding one group of cline frequency grids of each sourcesink node；
S3: for every group of cline frequency grid, according to the initial channelized frequencies of the quantity of its frequency grid and each frequency grid,
The centre frequency for determining this group of cline frequency grid is reset respectively according to the bandwidth of each frequency grid in the centre frequency two sides
A frequency grid, the actual frequency interval of side frequency gridValue range be [B- δ, B), wherein B indicate frequency grid
Bandwidth, δ indicate deviant, obtain the practical channelized frequencies of each frequency grid in this group of cline frequency gridIn determination
After good practical channelized frequencies, transmitting terminal and receiving end are sent relevant information to；
S4: transmitting terminal generates the subcarrier multiplex frequency signal of each frequency grid in electrical domain；
S5: each baseband signal is modulated to obtain sub-carrier signal by transmitting terminal with corresponding subcarrier multiplex frequency signal,
Each sub-carrier signal is multiplexed, optical signal is then converted to and is sent；
S6: receiving end is changed into electric signal after receiving optical signal, realizes that each sub-carrier signal separates according to practical channelized frequencies, adopts
Realize that baseband signal is restored with butterfly balanced device, method particularly includes:
Configure a butterfly balanced device for each sub-carrier signal, each butterfly equalizer setting there are three sub- balanced device, for
N-th isolated of sub-carrier signal, n=1,2 ..., N, N indicates the quantity of frequency grid in cline frequency grid, by it
It is equal that itself and two adjacent sub-carrier signals (i.e. (n-1)th, n-th and (n+1)th sub-carrier signal) input butterfly respectively
Equilibrium is carried out in three sub- balanced devices of weighing apparatus, cascading judgement then is carried out to balanced three obtained signal, and recovery obtains n-th
The baseband signal of a sub-carrier signal.
4. the method according to claim 3 for reducing the random frequency deviation of laser and influencing, which is characterized in that in the step S3
The centre frequency of every group of cline frequency grid is determining and resets frequency grid using following methods:
The quantity for remembering frequency grid in certain group cline frequency grid is N, and the initial channelized frequencies of each frequency grid is fn, n=1,
The centre frequency f of this group of cline frequency grid is arranged in 2 ..., N, bandwidth Bc=(f1+fN)/2, the reality of n-th of frequency grid
Channelized frequencies
5. the method according to claim 3 for reducing the random frequency deviation of laser and influencing, which is characterized in that the butterfly is balanced
The sub- balanced device of device is realized using linear transverse filter.
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| CN102857837A (en) * | 2011-06-30 | 2013-01-02 | 中兴通讯股份有限公司 | Encoding method and processing method of wavelength labels and nodes for flexible grid optical network |
| CN103248969A (en) * | 2012-02-08 | 2013-08-14 | 中兴通讯股份有限公司 | Method and device for grid capacity information notice and routing of flexible grid optical network |
| WO2015014405A1 (en) * | 2013-08-01 | 2015-02-05 | Telefonaktiebolaget Lm Ericsson (Publ) | Parameter control for optical multicarrier signal |
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| CN102857837A (en) * | 2011-06-30 | 2013-01-02 | 中兴通讯股份有限公司 | Encoding method and processing method of wavelength labels and nodes for flexible grid optical network |
| CN103248969A (en) * | 2012-02-08 | 2013-08-14 | 中兴通讯股份有限公司 | Method and device for grid capacity information notice and routing of flexible grid optical network |
| WO2015014405A1 (en) * | 2013-08-01 | 2015-02-05 | Telefonaktiebolaget Lm Ericsson (Publ) | Parameter control for optical multicarrier signal |
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