CN104243048A - Transmission performance optimization method and system based on simplicissimum in coherent light communication system - Google Patents

Abstract

The invention provides a transmission performance optimization method based on simplicissimum in a coherent light communication system. The method comprises the steps that the link gain configuration of an optical fiber is obtained, and a link transmission performance formula is obtained; the optimal incident power of a link and the first corresponding transmission performance are obtained according to the link transmission performance formula, and reference transmission performance is set according to the first transmission performance; the optimal link configuration and second corresponding transmission performance are obtained through an ergodic optimal algorithm, whether the second transmission performance is larger than the reference transmission performance or not is judged, the link transmission performance continues to be optimized through a simplicissimum method if the second transmission performance is larger than the reference transmission performance, and otherwise the incident power of a first span segment is changed into the optimal incident power. The transmission performance optimization problem of the coherent light communication system with the irregular link configuration and without dispersion compensation can be solved, and parameters capable of being dynamically adjusted in optimization comprise emission power and the gain of an optical fiber amplifier in each span segment in a light path.

Description

Based on the transmission performance optimization method and system of simplex in coherent optical communication system

Technical field

The present invention relates to technical field of photo communication, be specifically related to the transmission performance optimization method and system based on simplex in coherent optical communication system.

Background technology

In the optical fiber telecommunications system of reality, each fiber span transmission range, loss, amplifier gain configuration, Optical Switch Node decay configuration may be all not identical, there are differences.Under dynamic light path exchanges scene, link attenuation and gain often configure and non-optimal, restriction transmission performance.Owing to being subject to the impact of dispersion, complicated factor such as spontaneous gain radiation (ASE) noise, fiber nonlinear effect etc. in light transmission, system transfers performance obtains often through the mode of emulation, and its fast optimal design is difficult to realize.

Current existing optic path quality optimization scheme, mainly for direct-detection system, is mainly divided into following a few class:

(1) source transmission power adjustment scheme

Before light path connection request is set up, first according to the transmitter power of initial setting, calculate the light signal Optical Signal To Noise Ratio (OSNR) of receiving terminal.If Optical Signal To Noise Ratio is too small, then improve the signal incident power entering fiber span of transmitter power or source node generation, ensure that the nonlinear phase shift of light path entirety is lower than a certain fixed value simultaneously.Ensure that this light path reaches predefined index in the Optical Signal To Noise Ratio of receiving terminal with this.

(2) Separation Indexes prioritization scheme

At each ROADM node the dispersion compensation of optical path signal and attenuation regulated thus reach the object of optimizing dynamic transmission performance.In optimizing process, supposing can dynamic tuning by the dispersion compensator of each node in this light path, and the signal attenuation through this node also can dynamic adjustments.From source node, successively to each node under existing decay and compensation rate configuring condition, calculate the OSNR through each node, residual dispersion, enter the optical signal power of each node and the optical signal power of the output of this node and the accumulation nonlinear phase shift of this Nodes.The attenuation of this node and chromatic dispersion compensation quantity are searched in its adjustable range, chooses suitable attenuation and chromatic dispersion compensation quantity to ensure that OSNR, residual dispersion, I/O optical signal power and this node residual dispersion meet predefined requirement.Traverse destination node from source node, if at all Nodes, the OSNR of its output signal, I/O optical signal power, accumulation nonlinear phase shift and residual dispersion all meet predefined marginal range, then think that optimization completes.Otherwise, think that optimization cannot complete.Transmission performance assessment in this optimization method is according to depending on that non-linear cost that matching obtains is to obtain Q factor, therefore require that system sending and receiving end must be optimized compensation to optical path dispersion, and link will adopt the incoherent transmission system based on direct-detection of fixing dispersion compensation.In addition, the method also default transport link is rule configuration across section, and namely transmission link is made up of across section cascade identical transmission, respectively transmits across all parameters of section, comprises fiber type, fiber lengths, optical fiber dispersion, non-linear, attenuation coefficient etc. all identical.Therefore, it can only be applicable to link rule, have the direct-detection system of dispersion compensation.

In the transmission power adjustment scheme of source, light path intermediate node is not optimized and control signal power, and above-mentioned existing program all cannot be applicable to following scene: the coherent light transmission system that (1) does not adopt link dispersion to compensate; (2) each is across the not identical situation of section transmission configuration; (3) system of dispersion compensation that is not optimized of transmitting terminal, receiving terminal.Although there has also been the transmission performance optimization method for coherent light transmission system at present, the method adopts the mode of order optimization piecemeal to carry out, the regulated quantity choosing suitable point of adjustment and optimum of not active.

Summary of the invention

For the defect of prior art, based on the transmission performance optimization method and system of simplex in coherent optical communication system provided by the invention, can solve that link configuration is irregular, the transmission performance optimization problem of coherent light transmission system that non-dispersive compensates, and the parameter of dynamic conditioning can comprise each gain across fiber amplifier in section in source transmitting power and light path in optimizing.

First aspect, the invention provides a kind of transmission performance optimization method based on simplex in coherent optical communication system, the method comprises:

Obtain the link gain configuration of optical fiber, and obtain the formula of link transmission performance;

Obtain the optimum launched power of link and the first transmission performance of correspondence according to the formula of described link transmission performance, and reference transmission performance is set according to described first transmission performance;

The second transmission performance of link allocation optimum and correspondence is obtained by the optimal algorithm of traversal, judge whether described second transmission performance is greater than described reference transmission performance, if then adopt simplex method to continue to optimize the transmission performance of link, otherwise change to described optimum launched power by first across the incident power of section.

Preferably, the formula of described link transmission performance is:

${\mathrm{SNR}}_{\mathrm{Rx}}={(\frac{1}{{\mathrm{SNR}}_1}+\frac{1}{{\mathrm{SNR}}_2}+...+\frac{1}{{\mathrm{SNR}}_{\mathrm{Nspan}}})}^{-1}={\left(\underset{n=1}{\overset{\mathrm{Nspan}}{\mathrm{\Σ}}}\frac{1}{{\mathrm{SNR}}_n}\right)}^{-1}$

Wherein, SNR _rxrepresent the signal to noise ratio of receiving terminal, i.e. the transmission performance of link; SNR _nrepresent that n-th across the signal to noise ratio of section, and

${\mathrm{SNR}}_n=\frac{P_{\mathrm{in},n}\·e^{-\mathrm{\α}\·L_n}\·A_n}{P_{\mathrm{ASE},n}+P_{\mathrm{NLI},n}\·e^{-\mathrm{\α}\·L_n}\·A_n}$

Wherein, P _{in, n}represent that n-th across the incident optical signal power of section, L _nrepresent n-th across section across segment length, A _nrepresent that n-th across the amplifier gain of section, α represents decay, P _{aSE, n}represent that n-th across the spontaneous emission noise power of section amplifier, P _{nLI, n}represent that n-th across section amplifier nonlinearity noise power.

Preferably, the described optimal algorithm by traversal obtains the second transmission performance of link allocation optimum and correspondence, comprising:

Be variable by optical fiber first across section incident power and each gain setting across fiber amplifier in section, all combined situation of traversal variable, according to the computing formula of transmission performance, calculate receiving terminal transmission performance maximum time configuration combination, using the allocation optimum of described configuration combination as link, using maximum receiving terminal transmission performance as the second transmission performance.

Preferably, described employing simplex thought continues the transmission performance optimizing link, comprising:

S41: change to the incident power P in described link allocation optimum by first across the incident power of section _opt;

S42: by each absolute value abs (Δ A) across the optimum gain of section and the difference of initial gain=| A _{opt, n}-A _n| as the module of simplex;

S43: by all across abs in section (Δ A)=| A _{opt, n}-A _n| maximum to remove across the initial gain corresponding to section, replace with corresponding optimum gain, and go out transmission performance Q now according to the formulae discovery of transmission performance;

S44: judge whether Q is more than or equal to reference transmission performance, if then arrange corresponding regulated quantity, and exports Q, otherwise goes to step S42.

Preferably, the method also comprises: described regulated quantity is issued to each node adjuster, real-time dynamic adjustments by the interface of webmaster plane and transport plane, and is kept at by up-to-date configuration parameter in the database of webmaster or control plane.

Based on a transmission performance optimization system for simplex in coherent optical communication system, this system comprises:

Acquiring unit, for obtaining the link gain configuration of optical fiber, and obtains the formula of link transmission performance;

Setting unit, for obtaining the optimum launched power of link and the first transmission performance of correspondence according to the formula of described link transmission performance, and arranges reference transmission performance according to described first transmission performance;

Optimize unit, for being obtained the second transmission performance of link allocation optimum and correspondence by the optimal algorithm of traversal, judge whether described second transmission performance is greater than described reference transmission performance, if then adopt simplex method to continue to optimize the transmission performance of link, otherwise change to described optimum launched power by first across the incident power of section.

Preferably, this system also comprises:

Regulon, for described regulated quantity is issued to each node adjuster, real-time dynamic adjustments by the interface of webmaster plane and transport plane, and is kept at up-to-date configuration parameter in the database of webmaster or control plane.

Based on technique scheme, based on the transmission performance optimization method and system of simplex in coherent optical communication system provided by the invention, can solve that link configuration is irregular, the transmission performance optimization problem of coherent light transmission system that non-dispersive compensates, and the parameter of dynamic conditioning can comprise each gain across fiber amplifier in section in source transmitting power and light path in optimizing.This optimization method have employed simplex method, namely considers to promote optic path performance, also consider to avoid light path entire gain regulated quantity excessive or regulate number too much caused shake, time delay and transient state characteristic.Reduce network operation expense, effectively improve the transmission performance of coherent light transmission system.

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these figure.

Fig. 1 is the flow chart based on the transmission performance optimization method of simplex in the coherent optical communication system that provides of one embodiment of the invention;

Fig. 2 is the Part Methods flow chart based on the transmission performance optimization method of simplex in the coherent optical communication system that provides of another embodiment of the present invention;

Fig. 3 is the flow chart based on the transmission performance optimization method of simplex in the coherent optical communication system that provides of another embodiment of the present invention;

Fig. 4 is the schematic diagram of the irregular link configuration that another embodiment of the present invention provides;

Fig. 5 is the structure chart based on the transmission performance optimization system of simplex in the coherent optical communication system that provides of one embodiment of the invention.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.

As shown in Figure 1, the invention provides a kind of transmission performance optimization method based on simplex in coherent optical communication system, the method comprises the steps:

Step S1: the link gain configuration obtaining optical fiber, and obtain the formula of link transmission performance;

In the present embodiment, go out optic path performance when given light path configures by following formulae discovery, i.e. quality factor (Q factor) or BER.After the fiber span cascade different through some fiber lengths, amplifier gain is different, the final signal to noise ratio of receiving terminal system can be expressed as:

${\mathrm{SNR}}_{\mathrm{Rx}}={(\frac{1}{{\mathrm{SNR}}_1}+\frac{1}{{\mathrm{SNR}}_2}+...+\frac{1}{{\mathrm{SNR}}_{\mathrm{Nspan}}})}^{-1}={\left(\underset{n=1}{\overset{\mathrm{Nspan}}{\mathrm{\Σ}}}\frac{1}{{\mathrm{SNR}}_n}\right)}^{-1}---\left(1\right)$

Wherein, SNR _rxrepresent the signal to noise ratio of receiving terminal, i.e. the transmission performance of link, SNR _rxthis is only had to cause across the spontaneous emission noise produced in section and nonlinear noise; SNR _nrepresent that n-th across the signal to noise ratio of section, and

${\mathrm{SNR}}_n=\frac{P_{\mathrm{in},n}\·e^{-\mathrm{\α}\·L_n}\·A_n}{P_{\mathrm{ASE},n}+P_{\mathrm{NLI},n}\·e^{-\mathrm{\α}\·L_n}\·A_n}---\left(2\right)$

Wherein, P _{in, n}represent that n-th across the incident optical signal power of section, L _nrepresent n-th across section across segment length, A _nexpression n-th is across the amplifier gain of section, and α represents decay, P _{aSE, n}represent that n-th across the spontaneous emission noise power of section amplifier, P _{nLI, n}represent that n-th across section amplifier nonlinearity noise power.

Step S2: obtain the optimum launched power of link and the first transmission performance of correspondence according to the formula of described link transmission performance, and reference transmission performance is set according to described first transmission performance.

In the present embodiment, the trend that link transmission performance Q factor changes with launched power can be obtained according to the formula of link transmission performance, due to the impact of nonlinear noise, Q factor first increases and then decreases, obtain optimum launched power when the Q factor of link is maximum, and obtain the first corresponding transmission performance according to formula (1).

Step S3: the second transmission performance being obtained link allocation optimum and correspondence by the optimal algorithm of traversal, judge whether described second transmission performance is greater than described reference transmission performance, if then adopt simplex thought to continue to optimize the transmission performance of link, otherwise change to described optimum launched power by first across the incident power of section.

In step S3, the described optimal algorithm by traversal obtains the second transmission performance of link allocation optimum and correspondence, comprising:

Be variable by optical fiber first across section incident power and each gain setting across fiber amplifier in section, all combined situation of traversal variable, according to the computing formula of transmission performance, calculate receiving terminal transmission performance maximum time configuration combination, using the allocation optimum of described configuration combination as link, using maximum receiving terminal transmission performance as the second transmission performance.

As shown in Figure 2, be the flow chart adopting simplex thought to continue the transmission performance optimizing link in step S3, comprise the steps:

S41: change to the incident power P in described link allocation optimum by first across the incident power of section _opt;

S42: by each absolute value abs (Δ A) across the optimum gain of section and the difference of initial gain=| A _{opt, n}-A _n| as the module of simplex;

S43: by the absolute value abs (Δ A) of difference in all spans=| A _{opt, n}-A _n| maximum to remove across the initial gain corresponding to section, replace with corresponding optimum gain, and go out transmission performance Q now according to the formulae discovery of transmission performance;

S44: judge whether Q is more than or equal to reference transmission performance, if then go to step S45, otherwise go to step S42.

S45: corresponding regulated quantity is set, and exports Q.

In the present embodiment, the method also comprises: described regulated quantity is issued to each node adjuster, real-time dynamic adjustments by the interface of webmaster plane and transport plane, and is kept at by up-to-date configuration parameter in the database of webmaster or control plane.

As shown in Figure 3, based on the flow chart of the transmission performance optimization method of simplex in the coherent optical communication system that Fig. 3 provides for another embodiment, the method comprises the steps:

Step 301: the link configuration obtaining optical fiber according to gateway data storehouse.

Step 302: calculate optimum launched power P _opt-launchand the transmission performance Q of correspondence _opt-launch, and according to Q _opt-launchreference transmission performance Q is set _ref, the incident power P of allocation optimum is calculated by the optimized algorithm of traversal _opt, amplifier gain A _{opt, n}with the transmission performance Q of correspondence _opt.

Step 303: judge Q _optwhether be greater than Q _refif then go to step 305, otherwise go to step 304.

Step 304: arrange first across the incident power P of section _{in, 1}=P _opt-launch, export Q _opt-launch.

Step 305: P is set _{in, 1}=P _opt.

Step 306: calculating abs (Δ A)=| A _{opt, n}-A _n|, adopt simplex method to optimize link transmission performance, by maximum for interpolation across section A _nbe set to A _{opt, n}, calculate corresponding Q value according to formula (1).

Step 307: judge whether Q is greater than Q _refif then go to step 308, otherwise go to step 306.

Step 308: corresponding regulated quantity is set, and exports Q.

Carry out more clearly to illustrate below by a specific embodiment method that the embodiment of the present invention provides, as shown in Figure 4, Fig. 4 be one section ten across segment length the different and optical fiber link of random distribution, the physical quantity that wherein can regulate and physical device comprise: first across the incident power P of section _{in, 1}and A _k(k<n, n=10).Select PDM-QPSK-WDM system in scheme, WDM has 80 channels, channel spacing 50GHz, signal bandwidth 30GHz.Transmission performance optimization method based on simplex in the coherent optical communication system that the present embodiment provides comprises the steps:

Step 1: the link configuration obtaining optical fiber according to network management data storehouse.Parameter comprises light path and respectively transmits delivery fiber dispersion coefficient D=20ps/nm/km, attenuation alpha=0.2dB/km, non linear coefficient γ=1.3681*10^ (-3)/W/m across section, adjustable amplifier gain A _nbe respectively 24,6,8,8,18,14,8,14,8,6 (dB).

Step 2: in transmitter allowed band, transmitter power traversal scope chooses [-10,10] (dBm), can obtain P _opt-launch=0dBm, adopts the assessment formulae discovery shown in formula (1) to go out corresponding Q _opt-launch=20.3415dB, arranges reference transmission performance Q _ref=0.8+Q _opt-launch=21.1415dB, Q _refarranged by webmaster at control plane.Then in transmitter and amplifier allowed band, calculate receiving terminal Q factor maximum time Q _opt=21.5054dB, and the link allocation optimum value P of correspondence _opt=1.42dBm and amplifier gain A _{opt, n}be respectively: 17.92,6.72,8.00,11.36,16.67,11.97,10.03,11.97,7.28,6.00 (dB).

Step 3: compare Q _optwhether be greater than Q _ref, 21.5054>21.1415, need continue to optimize, continue step 4, by transmitter power P _{in, 1}be chosen for 1.42dBm.

Step 4: start to optimize according to the thought of simplex, concrete operations as shown in Figure 3, optimum gain configuration and the absolute value abs (Δ A) of initial gain difference=| A _{opt, n}-A _n|, wherein first is 6.08 to the maximum across the difference of section, gets A ₁=A _{opt, 1}, adopt the assessment formulae discovery Q=20.6558dB shown in formula (1).

Step 5: by Q and the Q calculated _refcompare, 20.6558<21.1415, get the corresponding regulated quantity A of Q ₁.

Step 6: modified first across after the amplifier gain of section, what present abs (Δ A) was maximum is the 4th across section, get A ₄=A _{opt, 4}, adopt the assessment formulae discovery Q=21.1912dB shown in formula (1).

Step 7: by Q and the Q calculated _refcompare, 21.1912>21.1415, get the corresponding regulated quantity A of Q ₄, optimizing process terminates, and goes to step 8.

Step 8: the regulated quantity optimized can be issued to each node adjuster, real-time dynamic adjustments by the interface of webmaster plane and transport plane.When transmission performance assessment unit is positioned over control plane (PCE or distributed control plane node), these regulated quantity information can be transmitted between each control plane node by signaling protocol, and by control plane node and transport plane node interface, regulated quantity is issued to each node adjustable device, realize the optimization to link, and up-to-date configuration parameter is kept in the database of webmaster or control plane.

Corresponding to the irregular link configuration of Fig. 4, suitable initial parameter P can be set _{in, 1}and A _k(k<n, n=10), then adopting simplex scheme to be optimized, is below the initial value arranged in this example, and optimum results, as shown in table 1:

Table 1 irregular link disposition and distribution optimization result

Can find out from upper table: the conclusion that second time is optimized meets judgment condition, and for returning the Configuration Values of webmaster, it only regulates first and second variablees.Certainly, in example, initial configuration also has other multiple situations,, transmission performance of poor quality for receiving end signal needs the optical fiber link improved further, and the present invention can when the least possible regulating allocation amount, effectively and efficiently the transmission performance of optimization system.Adopt simplex optimization scheme, choose the poised state regulating number of times and transmission performance two factors, thus realize the optimization to system configuration, ensure, under as far as possible few fiber amplifier regulates number situation, to obtain link transmission performance excellent as far as possible.

Based on the transmission performance optimization method of simplex in the coherent optical communication system that the present embodiment provides, can solve that link configuration is irregular, the transmission performance optimization problem of coherent light transmission system that non-dispersive compensates, and the parameter of dynamic conditioning can comprise each gain across fiber amplifier in section in source transmitting power and light path in optimizing.This optimization method have employed simplex method, namely considers to promote optic path performance, also consider to avoid light path entire gain regulated quantity excessive or regulate number too much caused shake, time delay and transient state characteristic.Reduce network operation expense, effectively improve the transmission performance of coherent light transmission system.

As shown in Figure 5, the invention provides the transmission performance optimization system based on simplex in a kind of coherent optical communication system, this system comprises: acquiring unit 501, setting unit 502 and optimization unit 503.

Acquiring unit 501, for obtaining the link gain configuration of optical fiber, and obtains the formula of link transmission performance;

Setting unit 502, for obtaining the optimum launched power of link and the first transmission performance of correspondence according to the formula of described link transmission performance, and arranges reference transmission performance according to described first transmission performance;

Optimize unit 503, for being obtained the second transmission performance of link allocation optimum and correspondence by the optimal algorithm of traversal, judge whether described second transmission performance is greater than described reference transmission performance, if then adopt simplex thought to continue to optimize the transmission performance of link, otherwise change to described optimum launched power by first across the incident power of section, and export the first transmission performance as regulated quantity.

Alternatively, this system also comprises: regulon, regulated quantity for being obtained by optimization unit 503 is issued to each node adjuster, real-time dynamic adjustments by the interface of webmaster plane and transport plane, and is kept at by up-to-date configuration parameter in the database of webmaster or control plane.

Above embodiment only in order to technical scheme of the present invention to be described, is not intended to limit; Although with reference to previous embodiment to invention has been detailed description, those of ordinary skill in the art is to be understood that; It still can be modified to the technical scheme described in foregoing embodiments, or carries out equivalent replacement to wherein portion of techniques feature; And these amendments or replacement, do not make the essence of appropriate technical solution depart from the spirit and scope of various embodiments of the present invention technical scheme.

Claims (7)

1. in coherent optical communication system based on a transmission performance optimization method for simplex, it is characterized in that, the method comprises:

Obtain the link gain configuration of optical fiber, and obtain the formula of link transmission performance;

Obtain the optimum launched power of link and the first transmission performance of correspondence according to the formula of described link transmission performance, and reference transmission performance is set according to described first transmission performance;

The second transmission performance of link allocation optimum and correspondence is obtained by the optimal algorithm of traversal, judge whether described second transmission performance is greater than described reference transmission performance, if then adopt simplex method to optimize the transmission performance of link, otherwise change to described optimum launched power by first across the incident power of section.

2. method according to claim 1, is characterized in that, the formula of described link transmission performance is:

${\mathrm{SNR}}_{\mathrm{Rx}}={(\frac{1}{{\mathrm{SNR}}_1}+\frac{1}{{\mathrm{SNR}}_2}+...+\frac{1}{{\mathrm{SNR}}_{\mathrm{Nspan}}})}^{-1}={\left(\underset{n=1}{\overset{\mathrm{Nspan}}{\mathrm{\&Sigma;}}}\frac{1}{{\mathrm{SNR}}_n}\right)}^{-1}$

Wherein, SNR _rxrepresent the signal to noise ratio of receiving terminal, i.e. the transmission performance of link; SNR _nrepresent that n-th across the signal to noise ratio of section, and

${\mathrm{SNR}}_n=\frac{P_{\mathrm{in},n}\&CenterDot;e^{-\mathrm{\&alpha;}\&CenterDot;L_n}\&CenterDot;A_n}{P_{\mathrm{ASE},n}+P_{\mathrm{NLI},n}\&CenterDot;e^{-\mathrm{\&alpha;}\&CenterDot;L_n}\&CenterDot;A_n}$

Wherein, P _{in, n}represent that n-th across the incident optical signal power of section, L _nrepresent n-th across section across segment length, A _nexpression n-th is across the amplifier gain of section, and α represents decay, P _{aSE, n}represent that n-th across the spontaneous emission noise power of section amplifier, P _{nLI, n}represent that n-th across section amplifier nonlinearity noise power.

3. method according to claim 1, is characterized in that, the described optimal algorithm by traversal obtains the second transmission performance of link allocation optimum and correspondence, comprising:

Be variable by optical fiber first across section incident power and each gain setting across fiber amplifier in section, all combined situation of traversal variable, according to the formula of transmission performance, calculate receiving terminal transmission performance maximum time configuration combination, using the allocation optimum of described configuration combination as link, using maximum receiving terminal transmission performance as the second transmission performance.

4. method according to claim 1, is characterized in that, described employing simplex method optimizes the transmission performance of link, comprising:

S41: change to the incident power P in described link allocation optimum by first across the incident power of section _opt;

S42: by each absolute value abs (Δ A) across the optimum gain of section and the difference of initial gain=| A _{opt, n}-A _n| as the module of simplex;

S43: by all across abs in section (Δ A)=| A _{opt, n}-A _n| maximum to remove across the initial gain corresponding to section, replace with corresponding optimum gain, and go out transmission performance Q now according to the formulae discovery of transmission performance;

S44: judge whether Q is more than or equal to reference transmission performance, if then arrange corresponding regulated quantity, and exports Q, otherwise goes to step S42.

5. method according to claim 4, it is characterized in that, the method also comprises: described regulated quantity is issued to each node adjuster, real-time dynamic adjustments by the interface of webmaster plane and transport plane, and is kept at by up-to-date configuration parameter in the database of webmaster or control plane.

6. in coherent optical communication system based on a transmission performance optimization system for simplex, it is characterized in that, this system comprises:

Acquiring unit, for obtaining the link gain configuration of optical fiber, and obtains the formula of link transmission performance;

Setting unit, for obtaining the optimum launched power of link and the first transmission performance of correspondence according to the formula of described link transmission performance, and arranges reference transmission performance according to described first transmission performance;

Optimize unit, for being obtained the second transmission performance of link allocation optimum and correspondence by the optimal algorithm of traversal, judge whether described second transmission performance is greater than described reference transmission performance, if then adopt simplex method to optimize the transmission performance of link, otherwise change to described optimum launched power by first across the incident power of section.

7. system according to claim 6, is characterized in that, this system also comprises:

Regulon, for described regulated quantity is issued to each node adjuster, real-time dynamic adjustments by the interface of webmaster plane and transport plane, and is kept at up-to-date configuration parameter in the database of webmaster or control plane.