CN114598945A

CN114598945A - Protection switching method, device and system in wavelength division multiplexing application and electronic equipment

Info

Publication number: CN114598945A
Application number: CN202011432069.3A
Authority: CN
Inventors: 万奇; 周胜; 邓宇; 刘卓; 吴超; 吴思遥; 成梦虹; 陆轶凡; 李端; 郝斌; 严彬; 魁政华; 周恩波
Original assignee: China Mobile Communications Group Co Ltd; China Mobile Group Design Institute Co Ltd
Current assignee: China Mobile Communications Group Co Ltd; China Mobile Group Design Institute Co Ltd
Priority date: 2020-12-07
Filing date: 2020-12-07
Publication date: 2022-06-07

Abstract

The invention provides a protection switching method, a device, a system and electronic equipment in wavelength division multiplexing application, comprising the following steps: continuously collecting main path combined waves of a main path light inlet and collecting standby path combined waves of a standby path light inlet; processing the main path composite wave and the standby path composite wave by using low-pass filtering to obtain N main path pilot signals and N standby path pilot signals; judging whether the N main pilot signals and the N standby pilot signals meet preset main-standby switching conditions, if so, switching the main-standby light paths; if not, the interval T1 is determined, and whether the N main pilot signals and the N standby pilot signals meet the preset main-standby switching condition is determined; the far-end return light waves on the main path and the standby path are obtained by adding corresponding pilot signals to far-end N-path service signals respectively, then carrying out electro-optical conversion and wave combination processing, and then passing the main path to the main path light inlet and the standby path to the standby path light inlet. The method provided by the invention can avoid the complex filtering processing requirement and reduce the hardware cost.

Description

Protection switching method, device and system in wavelength division multiplexing application and electronic equipment

Technical Field

The present invention relates to the field of wavelength division multiplexing application technologies, and in particular, to a protection switching method, device, system, and electronic device in wavelength division multiplexing application.

Background

The 5G mobile internet is one of key points for enabling the interconnection of everything, provides new requirements for a forward-transmission network, and needs to meet high requirements of high reliability, manageability and monitoring. The line protection becomes a necessary option for building a fronthaul network, the fronthaul network is required to support the line optical cable protection capability in principle, the switching time is required to be less than 50ms, and the fronthaul network protection capability requirement can be selected according to the 5G service plan. In a 5G semi-active system, an industry common practice of performing 1+1 line protection on a trunk optical fiber is to adopt protection switching based on an OLP optical switch: the optical power of the main link and the standby link is monitored in real time, whether protection switching is implemented or not is determined by judging whether the optical power of the main link and the standby link reaches a threshold value or not, and when switching is needed, the optical path is switched to the standby link through an optical switch.

The concrete implementation schemes in the prior art include the following:

1. and (3) light-entering port wave combination detection: fig. 1 is a schematic diagram illustrating a principle of an optical input/output combined wave detection method provided in the prior art, and as shown in fig. 1, in a 5G semi-active system, a main optical fiber has two groups of wavelengths in a single fiber and two directions. Typically 2 × N wavelengths are divided into two groups, i.e. N wavelengths on the AAU side and N wavelengths on the BBU side. And detecting the combined wave power through the line side light inlet to judge whether the fiber breaking fault exists.

2. Branch side spectroscopic monitoring: fig. 2 is a schematic diagram of a principle of branch side optical splitting monitoring provided in the prior art, and as shown in fig. 2, after a light splitting port is used for dropping waves, single-wave optical power of each wavelength of an AAU can be separately detected, multiple sets of hardware (PD arrays, operational amplifiers, optical splitters, optical fiber connectors) need to be introduced, and on the other hand, an optical switch and MUX need to be added on a line side.

3. And (3) filtering and monitoring at the light inlet: fig. 3 is a schematic diagram illustrating the principle of optical input filter monitoring provided in the prior art, and as shown in fig. 3, in order to prevent interference of reflection by an optical module on the side of the BBU during optical power detection at the wavelength combining port, a filter may be used to block reflected light from entering a detection PD, and there are mainly three filtering schemes. Fig. 4 is a schematic diagram of three filtering schemes provided in the prior art, as shown in fig. 4:

3.1) scheme 1: the AAU and BBU wavelengths are distributed in continuous frequency bands, and the red and blue band filtering is required to have higher isolation.

3.2) scheme 2: only one of the wavelengths is filtered.

3.3) scheme 3: a periodic comb filter (interleaver) is adopted to support a WDM system with closer wavelength intervals and narrower span.

The prior art scheme can be divided into two categories according to branch monitoring and trunk line monitoring, and each category has respective technical defects as follows:

branch monitoring scheme: the standby path detects the composite wave power, and the main path detects the single wave and accumulates, but the defects are as follows: a plurality of groups of hardware (PD arrays, operational amplifiers, optical splitters and optical fiber connectors) are additionally introduced, the comprehensive cost is higher, and the number of the hardware is linearly increased along with the number of the wavelengths, so that the technical expansion degree is limited and the integration degree is poorer; the line additionally introduces-3 dB insertion loss (optical switch + MUX). And the faults of the optical switch and the multiplexer/demultiplexer can not be detected accurately.

Monitoring scheme of the trunk line: the following disadvantages exist for different filtering schemes: as shown in scheme 1 of fig. 4, both the main and standby channels detect the combined wave optical power after filtering the red and blue bands; the wavelength of AAU and BBU is required to be distributed in a continuous frequency band, and the red and blue band filtering isolation has higher requirement, so that the method is more suitable for a system with larger wavelength interval, such as a CWDM system; as shown in scheme 2 of fig. 4, the trunk line monitors the optical power after filtering out only a single wavelength; therefore, it is not possible to distinguish between a branch-side fault or a trunk-side fault; as shown in scheme 3 of fig. 4, a periodic comb filter (interleaver) is required to detect the power of the multiplexed light after periodic filtering, so that only WDM systems with relatively close wavelength intervals and relatively narrow span, such as DWDM systems, are supported.

Moreover, an intuitive warning information prompting system is lacked in the existing scheme on a management interface, and the position and the type of the fault cannot be quickly determined.

Therefore, how to avoid the problem that hardware cost is high due to branch monitoring for switching determination in the existing wavelength division multiplexing application on main and branch single wave monitoring, or the existing incomplete filtering technology caused by trunk line detection is difficult to obtain accurate single wave fault condition of each branch still needs to be solved urgently by technical personnel in the field.

Disclosure of Invention

The invention provides a protection switching method, a device, a system and electronic equipment in wavelength division multiplexing application, which are used for solving the defects that the hardware cost of branch monitoring is high for main and branch single wave monitoring in the existing wavelength division multiplexing application or the existing incomplete filtering technology is difficult to obtain the accurate single wave fault condition of each branch caused by main line detection, pilot signals are inserted into each far-end service signal, after the light inlet of a local end collects the combined signal transmitted from the main and branch at the far end, the light is converted into electricity, then the pilot signals are filtered, whether the protection switching processing is needed or not is judged according to the pilot signals of each far-end service signal output by the main and standby lines, the complex filtering processing of the single wave signals of different service lines in the same end signal which are needed to be distinguished not only the far-end service signals and the local-end service signals can be avoided, and high comprehensive hardware cost caused by respectively installing single-wave detectors on the branches is avoided.

The invention provides a protection switching method in wavelength division multiplexing application, which comprises the following steps:

continuously collecting main path composite waves of the light waves emitted by the local side of the main path light inlet and the far-end return light waves, and collecting standby path composite waves of the light waves emitted by the local side of the standby path light inlet and the far-end return light waves;

processing the main path composite wave and the standby path composite wave by using low-pass filtering to obtain N main path pilot signals and N standby path pilot signals;

judging whether the N main pilot signals and the N standby pilot signals meet preset main-standby switching conditions, if so, sending a switching processing command to control a main-standby switching switch to switch the light path;

if not, presetting a first time length T1 at intervals, and judging whether the N main road pilot signals and the N standby road pilot signals meet the preset main-standby switching condition again;

the far-end return light waves on the main path and the standby path are obtained by respectively adding corresponding pilot signals to far-end N-path service signals, then carrying out electro-optical conversion and wave combination processing, and then respectively transmitting the signals to the main path light inlet and the standby path light inlet through the main path, wherein N is a positive integer.

According to the protection switching method in the wavelength division multiplexing application provided by the present invention, if it is determined that the N main pilot signals and the N standby pilot signals satisfy the preset main/standby switching condition, the main/standby protection switching processing is performed, specifically including:

determining that the difference value between any main road pilot signal strength of the N main road pilot signals and the corresponding standby road pilot signal strength is greater than the preset maximum difference value when the main road pilot signal strength is less than the preset intensity threshold or less than the corresponding standby road pilot signal strength, and determining that any main road pilot signal is unqualified;

and if the N main path pilot signals are determined to be unqualified, performing main/standby protection switching processing.

According to the protection switching method in the wavelength division multiplexing application provided by the invention, after the main/standby protection switching processing is performed, a second time duration T2 is preset at intervals, and whether the N main pilot signals and the N standby pilot signals meet the preset main/standby switching condition is judged again.

According to the protection switching method in the wavelength division multiplexing application provided by the present invention, after the processing of the main path combined wave and the standby path combined wave by using low-pass filtering to obtain N main path pilot signals and N standby path pilot signals, the method further includes:

and detecting and determining that the N main path pilot signals and the N standby path pilot signals are correct to correspond to the pilot signals corresponding to the addition of the N far-end service signals.

According to the protection switching method in wavelength division multiplexing application provided by the present invention, the detecting and determining that the N main path pilot signals and the N standby path pilot signals correspond to the far end N service signals respectively added with the corresponding pilot signals correctly further comprises:

and if any main path pilot signal or any standby path pilot signal is detected not to be matched with the pilot signal added by the far end and the corresponding path service signal, carrying out error check on the far end optical module, the far end multiplexer/demultiplexer and the MCU equipment for loading the pilot signal.

According to the protection switching method in wavelength division multiplexing application provided by the present invention, before judging whether the N main pilot signals and the N standby pilot signals satisfy the preset main/standby switching condition again, the method further comprises:

determining a main pilot signal with a difference value larger than a preset maximum difference value between the main pilot signal intensity and the corresponding standby pilot signal intensity as a problem pilot when the main pilot signal intensity is smaller than a preset intensity threshold or smaller than the corresponding standby pilot signal intensity;

if one or more problem pilots exist, the faulty line range and the faulty device range are determined based on all the problem pilots.

The invention also provides a protection switching device in wavelength division multiplexing application, which comprises:

the wave combination acquisition unit is used for continuously acquiring main-path wave combination of the main-path light-inlet local side transmitting light waves and the far-end returning light waves and acquiring standby-path wave combination of the standby-path light-inlet local side transmitting light waves and the far-end returning light waves;

a low-pass filtering unit, configured to process the main path combined wave and the standby path combined wave by using low-pass filtering to obtain N main path pilot signals and N standby path pilot signals;

the protection switching unit is used for judging whether the N main path pilot signals and the N standby path pilot signals meet preset main/standby switching conditions, and if so, performing main/standby protection switching processing;

if not, presetting a first time length T1 at intervals, and judging whether the N main pilot signals and the N standby pilot signals meet preset main-standby conversion conditions again;

The invention also provides a protection switching system in wavelength division multiplexing application, which comprises the protection switching device in wavelength division multiplexing application, a remote end device AAU, a local end device BBU, a remote passive box, a local side multiplexer/demultiplexer, a main/standby switch, a main duplex fiber and a standby duplex fiber,

the far-end equipment AAU is used for adding corresponding pilot signals to the far-end N-path service signals respectively, then carrying out electro-optical conversion to obtain N-path added pilot signals and sending the N-path added pilot signals to the far-end passive box;

the far-end passive box is used for broadcasting a far-end composite wave obtained by carrying out composite wave processing on the N paths of pilot signals to the main path duplex optical fiber and the standby path duplex optical fiber to respectively obtain a main path composite wave and a standby path composite wave;

the protection switching device in the wavelength division multiplexing application is used for collecting main path combined waves and standby path combined waves at a main path light inlet and a standby path light inlet;

the main/standby switch is used for receiving the switching processing command of the protection switching device in the wavelength division multiplexing application to switch the optical path;

the local side wavelength multiplexing and demultiplexing equipment is used for multiplexing the far-end wavelength output by the main/standby changeover switch to output far-end N-path service optical signals;

the local side equipment BBU is used for performing electro-optical conversion on the local side N-path service signals to obtain N-path optical signals, and transmitting the N-path optical signals to the local side add/drop equipment to output local side transmitting optical waves.

The present invention further provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and capable of running on the processor, wherein the processor implements the steps of the protection switching method in the wavelength division multiplexing application as described in any of the above when executing the program.

The present invention also provides a non-transitory computer readable storage medium having stored thereon a computer program which, when being executed by a processor, implements the steps of the protection switching method in a wavelength division multiplexing application as described in any of the above.

The protection switching method, the device, the system and the electronic equipment in the wavelength division multiplexing application provided by the invention collect the main path composite wave of the transmitting light wave and the far-end returning light wave of the main path light inlet local side and collect the backup path composite wave of the transmitting light wave and the far-end returning light wave of the backup path light inlet local side by continuously collecting the main path composite wave; processing the main path composite wave and the standby path composite wave by using low-pass filtering to obtain N main path pilot signals and N standby path pilot signals; judging whether the N main pilot signals and the N standby pilot signals meet preset main-standby switching conditions, if so, sending a switching processing command to control a main-standby switching switch to switch the light path; if not, presetting a first time length T1 at intervals, and judging whether the N main road pilot signals and the N standby road pilot signals meet the preset main-standby switching condition again; the far-end return optical waves on the main path and the standby path are obtained by respectively adding corresponding pilot signals to far-end N-path service signals, then performing electro-optical conversion and wave combination processing, and then respectively transmitting the signals to the main path light inlet and the standby path light inlet through the main path, wherein N is a positive integer. Because the pilot signal is inserted into each path of service signal at the far end, after the combined wave transmitted by the main path and the branch path from the far end is collected at the optical inlet of the local end, the optical-to-electrical conversion is carried out firstly, then the pilot signal is filtered out, and whether the protection switching processing is needed or not is judged according to the pilot signal of each far end service signal output by the main path and the standby path, so that the complex filtering processing of distinguishing the single wave signals of different service paths in the same end signal from the far end service signal and the local end service signal can be avoided, the high cost of the integrated hardware caused by respectively installing a single wave detector on the branch path can be avoided, meanwhile, the main path combined wave and the standby path combined wave for monitoring are continuously collected, and the judgment of whether the switching is needed or not is carried out again after the main path combined wave and the standby path combined wave do not need to be switched is carried out again after the judgment of a period of time T1, and the judgment of whether the switching condition is met or not carried out again after a period of time T1 is carried out every time when the judgment of the switching is carried out, and the continuous quality inspection of the main and standby paths in the wavelength division multiplexing application process is realized in a circulating manner, the main and standby paths are switched in real time, and the optimal main optical fiber line is continuously searched for carrying out remote optical wave transmission. Therefore, the method, the device, the system and the electronic equipment provided by the invention avoid the requirement of complex filtering processing and also reduce the hardware cost.

Drawings

In order to more clearly illustrate the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic diagram illustrating a principle of a method for detecting a light-incident combined wave according to the prior art;

FIG. 2 is a schematic diagram of branch side spectroscopy monitoring provided by the prior art;

FIG. 3 is a schematic diagram illustrating a filtering monitor for an optical input port according to the prior art;

FIG. 4 is a schematic diagram of three filtering schemes provided by the prior art;

fig. 5 is a schematic flow chart of a protection switching method in a wavelength division multiplexing application provided in the present invention;

fig. 6 is a schematic structural diagram of a protection switching system in a wavelength division multiplexing application provided in the present invention;

FIG. 7 is a schematic diagram of troubleshooting based on problem pilots provided by the present invention;

fig. 8 is a schematic structural diagram of a protection switching device in a wavelength division multiplexing application provided in the present invention;

fig. 9 is a schematic diagram of a protection switching operation flow in the wavelength division multiplexing application provided by the present invention;

fig. 10 is a schematic physical structure diagram of an electronic device according to the present invention;

the reference numerals in fig. 7 illustrate:

the method comprises the following steps: a transmitting optical fiber from the AAU optical module to a far-end passive box;

secondly, the step of: a far-end passive box is connected to a receiving optical fiber of the AAU optical module;

③: a wave combining optical fiber from a far-end passive box to a local side device;

fourthly, the method comprises the following steps: a receiving optical fiber from the local side equipment to the BBU optical module;

fifthly: a BBU optical module is connected with a transmitting optical fiber of the local side equipment;

sixthly, the method comprises the following steps: an AAU optical module;

seventh, the method comprises the following steps: BBU optical module.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The existing network element function registration information auditing generally has the problems that the access time is greatly delayed due to the long process caused by manpower, and the configuration data of various different network element functions cannot be automatically audited. The protection switching method in the wavelength division multiplexing application of the present invention is described below with reference to fig. 5 to 7. Fig. 5 is a schematic flow chart of a protection switching method in wavelength division multiplexing application provided by the present invention, and as shown in fig. 5, the method includes:

step 510, continuously collecting the main path composite wave of the main path light-incoming port office side transmitting light wave and the far-end returning light wave, and collecting the backup path composite wave of the backup path light-incoming port office side transmitting light wave and the far-end returning light wave.

Specifically, the system structure applied by the protection switching method in wavelength division multiplexing application provided by the invention is introduced first, fig. 6 is a schematic structural diagram of a protection switching system in wavelength division multiplexing application, as shown in fig. 6, the present invention performs combined wave detection at an optical input port, and separately detects combined waves on two trunk lines (i.e. a main optical fiber and a standby optical fiber), where the combined waves are synthesized by a local side transmitting optical wave and a far side returning optical wave, the optical wave emitted by the local side is an optical signal which can be transmitted on one line and is obtained by converting N service signals of the local side into optical signals and then combining the optical signals, the far-end return optical wave is an optical signal which can be transmitted on one line and is obtained by converting N service signals of the far end into optical signals and then combining the optical signals, the optical signal is broadcast to two trunk lines (i.e., a main optical fiber and a standby optical fiber) to be transmitted for a long distance and then reach an optical inlet. However, the far-end return light wave in the invention is obtained by adding the corresponding pilot signals to the far-end N-path service signals respectively, then performing electro-optical conversion and wave combination processing, and then transmitting the signals to the main path light inlet and the standby path light inlet through the main path respectively, adding the pilot signals to the far-end, and the main path wave combination and the standby path wave combination detected by the office end at the light inlet are used as data sources for subsequently extracting the pilot signals received by the office end, thereby providing the comparison between the transmission states and the advantages of the main path optical fiber and the standby path optical fiber in the process of judging long-distance transmission based on the received pilot signals at the office end, and providing the decision basis for switching between the main path and the standby paths.

And 520, processing the main path combined wave and the standby path combined wave by using low-pass filtering to obtain N main path pilot signals and N standby path pilot signals.

Specifically, since the N paths of far-end service signals received by the far-end AAU device are all high-frequency signals, different low-frequency signals corresponding to each service signal are loaded on the service signals as pilot signals, and the pilot signals are extracted by directly using low-pass filtering processing after the combined wave of the main path and the standby path is collected at the optical inlet of the office BBU, so as to obtain N pilot signals corresponding to the far-end service signals transmitted by the main path and N pilot signals corresponding to the far-end service signals transmitted by the standby path. The low-pass filtering process used here is much simpler and easier than the filtering process of a single-wave signal that is to distinguish both a far-end service signal and an office-end service signal and also to distinguish different service lines in the same-end signal, and the current filtering technology can extract a low-frequency pilot signal well.

Step 530, judging whether the N main pilot signals and the N standby pilot signals meet a preset main-standby switching condition, if so, sending a switching processing command to control the main-standby switching switch to switch the optical path;

Specifically, filtering is performed to obtain a pilot frequency received at the light inlet, each pilot frequency received at the light inlet substantially corresponds to a pilot frequency loaded by each far-end service signal, whether the transmission quality of the current main path and the transmission quality of the current main path are lower than the transmission quality of the current standby path can be determined by comparing the difference between two pilot frequencies after long-distance transmission through the main path optical fiber or the standby path optical fiber and the difference between the two pilot frequencies and the original pilot frequency, if the difference is greater than a predetermined maximum difference, switching between the main path and the standby path can be considered, where a predetermined maximum difference is usually set because the main path is not switched immediately as long as the difference between the transmission quality of the main path and the standby path is determined, because the acquired monitoring data is an instantaneous value, otherwise, switching between the main path and the standby path would have a time-cut-off effect on transmission of the optical signal and the electrical signal in the system, therefore, only when the transmission quality of the main path is poor to a certain degree, even if transmission interruption caused by switching exists, the transmission quality obtained by the main-standby switching can be improved so as to reduce the negative influence of the transmission interruption caused by switching to be negligible. In addition, as the main path composite wave and the standby path composite wave which are collected for monitoring are continuously carried out all the time, and the judgment on whether the switching is required is carried out again at intervals of T1 after the main path and the standby path are judged to be not required to be switched, when the judgment on whether the switching requirement is met is carried out again at intervals of T1 after the judgment on the result that the switching is not required each time, the continuous quality inspection of the main path and the standby path in the wavelength division multiplexing application process is circularly realized, the switching of the main path and the standby path is carried out in real time, and the optimal main optical fiber line is continuously searched for carrying out the transmission of the remote optical wave.

The method provided by the invention collects the standby combined wave of the transmitting light wave and the far-end returning light wave of the local side of the standby light inlet by continuously collecting the main-path combined wave of the transmitting light wave and the far-end returning light wave of the local side of the main-path light inlet; processing the main path composite wave and the standby path composite wave by using low-pass filtering to obtain N main path pilot signals and N standby path pilot signals; judging whether the N main pilot signals and the N standby pilot signals meet preset main-standby switching conditions, if so, sending a switching processing command to control a main-standby switching switch to switch the light path; if not, presetting a first time length T1 at intervals, and judging whether the N main road pilot signals and the N standby road pilot signals meet the preset main-standby switching condition again; the far-end return light waves on the main path and the standby path are obtained by respectively adding corresponding pilot signals to far-end N-path service signals, then carrying out electro-optical conversion and wave combination processing, and then respectively transmitting the signals to the main path light inlet and the standby path light inlet through the main path, wherein N is a positive integer. Because the pilot signal is inserted into each path of service signal at the far end, after the combined wave transmitted by the main path and the branch path from the far end is collected at the optical inlet of the local end, the optical-to-electrical conversion is carried out firstly, then the pilot signal is filtered out, and whether the protection switching processing is needed or not is judged according to the pilot signal of each far end service signal output by the main path and the standby path, so that the complex filtering processing of distinguishing the single wave signals of different service paths in the same end signal from the far end service signal and the local end service signal can be avoided, the high cost of the integrated hardware caused by respectively installing a single wave detector on the branch path can be avoided, meanwhile, the main path combined wave and the standby path combined wave for monitoring are continuously collected, and the judgment of whether the switching is needed or not is carried out again after the main path combined wave and the standby path combined wave do not need to be switched is carried out again after the judgment of a period of time T1, and the judgment of whether the switching condition is met or not carried out again after a period of time T1 is carried out every time when the judgment of the switching is carried out, and the continuous quality inspection of the main and standby paths in the wavelength division multiplexing application process is realized in a circulating manner, the main and standby paths are switched in real time, and the optimal main optical fiber line is continuously searched for carrying out remote optical wave transmission. Therefore, the method provided by the invention avoids the complex filtering processing requirement and also reduces the hardware cost.

On the basis of the foregoing embodiment, in the method, if it is determined that the N main pilot signals and the N standby pilot signals satisfy the preset main/standby switching condition, the main/standby protection switching processing is performed, specifically including:

Specifically, the preset primary-standby switching condition is further limited here. Firstly, it needs to be determined whether each primary pilot signal has a problem, that is, whether the primary pilot signal is a problem primary pilot, and there are two conditions for determining whether any primary pilot signal is a problem, and if these two conditions satisfy at least one, it can be determined that any primary pilot signal is a problem primary pilot, and these two conditions are: 1. the intensity of any main road pilot signal is smaller than the preset intensity threshold, the preset intensity threshold in the condition is usually based on an original pilot signal added to a far-end corresponding service signal corresponding to any main road pilot signal, that is, the attenuation coefficient of the received pilot signal intensity on the basis of the emitted original pilot signal intensity has an upper limit in the formula under the condition that the optical fiber has no fault, and cannot be attenuated too much, that is, the intensity of any main road pilot signal is not smaller than the preset intensity threshold, and once the intensity of any main road pilot signal is smaller than the preset intensity threshold, the any main road pilot signal is determined to be a problem main road pilot; 2. when the strength of the main pilot signal is lower than the strength of the corresponding auxiliary pilot signal, the difference between the main pilot signal and the corresponding auxiliary pilot signal is greater than the preset maximum difference, namely the main pilot signal is compared with the corresponding auxiliary pilot signal, the correspondence here means that the pilot loaded by the same far-end service signal is transmitted by two remote optical fibers and then the relationship between the two pilot signals is received at the local end light inlet, namely the main pilot signal and the corresponding auxiliary pilot signal are from the same original pilot signal loaded on the same far-end service signal, and when the strength of the main pilot signal is determined to be smaller than the strength of the corresponding auxiliary pilot signal, if the strength of the main pilot signal is determined to be greater than the preset maximum difference, any main pilot signal is determined to be the problem main pilot signal. The triggering condition for switching between main and standby modes is to determine that all the main pilot channels are problem main pilot channels, but if one pilot channel is not a problem pilot channel, the main and standby switching is not executed.

Further exemplifying: the following mapping relation is established in the wavelength division multiplexing system: each wavelength is assigned a unique pilot frequency. Each pilot frequency is referred to as a channel. When the main path works normally, the number of paths (wavelength number) of the combined wave signal (service signal, such as eCPRI/CPRI) and the number of paths of the pilot channel are in one-to-one correspondence, and the pilot signal intensity of each channel is greater than the threshold value Pth. When triggered by any of the following events:

1. if the pilot signal strength of one channel of the main path is detected to be lower than a threshold value Pth, sending an LOS alarm to the channel; 2. if the pilot signal strength of one channel of the main path is detected to be lower than the pilot signal strength delta P0 of the channel of the standby path, an LOS alarm is sent out to the channel; 3. any other reason, such as a manual flag (e.g., an alarm is manually inserted into such a maintenance operation), issues a LOS alarm for that channel.

If all if LOS alarms occur simultaneously on all channels, a multilinos alarm is issued. And when the main path has a MultiLOS alarm and at least one standby path has no MultiLOS alarm, switching the optical switch to any standby path without the alarm to realize protection switching.

The far-end wavelength division multiplexing system AAU (including the wavelength division multiplexing module with pilot, the wavelength division multiplexer, and the optical splitter) and the office wavelength division multiplexing system BBU are also described here:

for far-end wavelength division multiplexing systems AAU:

1. 1 corresponding pilot signal is modulated at each wavelength by an electro-optical modulation technique within each wavelength division multiplexed optical module. The frequency of the pilot is usually low, usually 0 Hz-100 MHz, and the depth is usually 0% -10%. The pilot signal does not affect the traffic signal (e.g., eCPRI/CPRI) of the original optical module.

2. And a plurality of optical modules with pilot frequencies are coupled into an optical fiber at a far end through a wavelength division multiplexer.

3. The optical signal 1 after being combined is divided into N paths (N is more than or equal to 2) by the optical splitter and respectively transmitted to the local side detection equipment.

For the local side wavelength division multiplexing system BBU:

1. after N paths of optical fibers enter local side equipment, pilot frequency intensity is respectively detected for the main path and the standby path.

2. In each fiber there are 1 splitter and 1 photodetector, e.g., PIN or APD, for detecting the combined optical signal.

3. The combined wave optical signal is photoelectrically converted into an electric signal by a photoelectric detector, and is sampled into a digital signal by an ADC.

On the basis of the foregoing embodiment, in the method, after the main/standby protection switching processing is performed, a second time duration T2 is preset at intervals, and it is determined again whether the N main pilot signals and the N standby pilot signals satisfy preset main/standby switching conditions.

Specifically, whether the condition for circularly detecting the main/standby switching is satisfied or not is supplemented, that is, it is considered that even if the currently existing main circuit fault problem is found for switching, the latest main circuit that may be selected is likely to have transmission quality inferior to that of the standby circuit in the future, and the transmission quality of the main/standby circuit needs to be always detected, that is, after the main/standby switching is determined to be required in the previous time, after the switching is completed, the interval preset second time duration T2 continues to jump to the determination of whether the switching condition is satisfied, so that the continuous quality of the main/standby circuit in the wavelength division multiplexing application process is examined and the main/standby circuit is switched in real time, and the optimal main optical fiber line is continuously found for remote optical wave transmission. In general, the preset second time period T2 is longer than the preset first time period T1, because the negative effect of transmission truncation caused by frequent switching needs to be considered just after switching is performed, so as to avoid frequent switching, and the problem of failure will not occur in a short time due to the fact that the optimal optical fiber line is just switched, therefore, the detection time for switching can be properly prolonged backwards.

On the basis of the foregoing embodiment, in the method, after the processing the main path combined wave and the auxiliary path combined wave by using low-pass filtering to obtain N main path pilot signals and N auxiliary path pilot signals, the method further includes:

Specifically, after detecting N main path pilot signals and N standby path pilot signals, N corresponding relationships between the N main path pilot signals and the N standby path pilot signals are also determined, where the correspondence refers to a relationship between two pilot signals received at a local-side light-in port after the pilot frequency loaded by the same corresponding far-end service signal is transmitted through two remote optical fibers, that is, the main path pilot frequency and the standby path pilot frequency corresponding to the main path pilot frequency are found out, and the finding basis is that the two pilot signals are derived from the same original pilot signal loaded on the same far-end service signal. Only after the N main road pilot signals and the N standby road pilot signals are determined to be respectively corresponding to the pilot signals corresponding to the addition of the N far-end N service signals, the subsequent comparison of the main road pilot and the intensity threshold value of the main road pilot can be carried out, the comparison of the main road pilot and the intensity of the standby road pilot corresponding to the main road pilot can be carried out, if the corresponding relation is not determined to be correct, the comparison with the wrong intensity threshold value of the main road pilot cannot obtain a meaningful result, and the comparison of the main road pilot and the intensity of the standby road pilot not corresponding to the main road pilot cannot obtain a meaningful result.

On the basis of the foregoing embodiment, in the method, the detecting and determining that the N main pilot signals and the N standby pilot signals correspond to correct pilot signals to which corresponding pilot signals are added respectively to N far-end traffic signals further includes:

Specifically, if it is detected that any main path pilot signal or any backup path pilot signal is not matched with the pilot signal added by the far end and the corresponding path service signal, the problem of the line before the optical access and the problem of the equipment on the line are immediately checked.

On the basis of the foregoing embodiment, before determining whether the N main pilot signals and the N standby pilot signals satisfy the preset main/standby switching condition again, the method further includes:

Specifically, although the triggering condition of the active-standby switching is not reached, one or more problem pilots are still found to exist, and the faulty line range and the faulty device range are determined based on all the problem pilots. For example, the following steps are carried out: when the main pilot frequency corresponding to the third service line is found to be the problem pilot frequency, and the main pilot frequencies corresponding to other service lines are not the problem pilot frequency, it is determined that the problem is not the problem pilot frequency on the remote transmission optical fiber, and the investigation range can be narrowed to the extent that the corresponding third service line and the remote optical module are investigated before the combined wave enters the remote optical fiber for transmission. Fig. 7 is a schematic diagram of troubleshooting based on problem pilot frequency provided by the present invention, and as shown in fig. 7, a network management system analyzes according to alarm information including problem pilot frequency information reported by devices, and dyes a fault source generated by a corresponding alarm, so that a user can determine that an AAU optical module-passive device, a combined wave optical path, and a local side device-BBU optical module have a fault according to the dyeing, thereby facilitating delimitation. The division of each position in the forwarding network is shown in fig. 7, and the position is (r): a transmitting optical fiber from the AAU optical module to a far-end passive box; position two: a far-end passive box is connected to a receiving optical fiber of the AAU optical module; position (c): a wave combining optical fiber from a far-end passive box to a local-end device; position (iv): a receiving optical fiber from the local side equipment to the BBU optical module; position (v): a BBU optical module is connected with a transmitting optical fiber of the local side equipment; position (c): an AAU optical module; position (c): BBU optical module.

According to different equipment types and fault point positions, dyeing can be carried out as follows: it should be noted here that, the fault detection mechanisms of different device types are different, and the accuracy of positioning the fault source is also different; since each wavelength of single carrier amplitude modulation needs a set of detection circuit, the detection is generally only performed on the optical path in the AAU direction, the BBU direction is not detected, and the positions of partial faults cannot be accurately distinguished.

Firstly, a device type a: multi-carrier amplitude modulation

1. In the position I, a fault is generated, and the optical fiber in the position I and the optical module in the position II are dyed;

2. when the optical fiber fails, the optical fiber and the optical module are dyed;

3. position III, dyeing the optical fiber and the optical module;

4. fault, dyeing the optical fiber at the position (IV) and the optical fiber at the position (VII);

5. position, dyeing optical fiber and position light module;

6. position sixthly, dyeing the optical fiber at the first position and the optical module at the sixth position after the fault occurs;

7. and position (c) dyeing the optical fiber and the optical module.

II, equipment type b: single carrier amplitude modulation

1. A fault is positioned, and an optical fiber at the position I and an optical module at the position II are dyed;

2. the position II is in fault, and the optical fiber and the optical module are dyed;

3. position III, dyeing the optical fiber and the optical module;

4. and sixthly, dyeing the optical fiber and the optical module at the position I when the fault occurs.

The method provided by the invention can also solve the problem that the position and the type of the fault can not be quickly determined due to the lack of an intuitive warning information prompting system in the existing scheme, not only can the main-main switching protection be carried out by identifying the main-main fault in time, but also the fault range can be more accurately positioned according to the warning information of the problem service line under the condition that the main-main fault is not large but the problem service line exists.

The protection switching device in the wavelength division multiplexing application provided by the present invention is described below, and the protection switching device in the wavelength division multiplexing application described below and the protection switching method in the first wavelength division multiplexing application described above may be referred to in a corresponding manner.

Fig. 8 is a schematic structural diagram of a protection switching device in wavelength division multiplexing application provided in the present invention, as shown in fig. 8, the device includes a combined wave collecting unit 810, a low-pass filtering unit 820 and a protection switching unit 830, wherein,

the combined wave collecting unit 810 is configured to continuously collect a main path combined wave of the main path light-incoming port office end transmitting light waves and the far-end return light waves, and collect a standby path combined wave of the standby path light-incoming port office end transmitting light waves and the far-end return light waves;

the low-pass filtering unit 820 is configured to process the main path combined wave and the standby path combined wave by using low-pass filtering to obtain N main path pilot signals and N standby path pilot signals;

the protection switching unit 830 is configured to determine whether the N main pilot signals and the N standby pilot signals meet a preset main-standby switching condition, and if yes, perform main-standby protection switching processing;

The main path composite wave of the transmitting light wave and the far-end returning light wave of the local side of the main path light inlet is continuously collected, and the standby path composite wave of the transmitting light wave and the far-end returning light wave of the standby path light inlet is collected; processing the main path composite wave and the standby path composite wave by using low-pass filtering to obtain N main path pilot signals and N standby path pilot signals; judging whether the N main pilot signals and the N standby pilot signals meet preset main-standby switching conditions, if so, sending a switching processing command to control a main-standby switching switch to switch the light path; if not, presetting a first time length T1 at intervals, and judging whether the N main road pilot signals and the N standby road pilot signals meet the preset main-standby switching condition again; the far-end return light waves on the main path and the standby path are obtained by respectively adding corresponding pilot signals to far-end N-path service signals, then carrying out electro-optical conversion and wave combination processing, and then respectively transmitting the signals to the main path light inlet and the standby path light inlet through the main path, wherein N is a positive integer. Because the pilot signal is inserted into each path of service signal at the far end, after the combined wave transmitted by the main path and the branch path from the far end is collected at the optical inlet of the local end, the optical-to-electrical conversion is carried out firstly, then the pilot signal is filtered out, and whether the protection switching processing is needed or not is judged according to the pilot signal of each far end service signal output by the main path and the standby path, so that the complex filtering processing of distinguishing the single wave signals of different service paths in the same end signal from the far end service signal and the local end service signal can be avoided, the high cost of the integrated hardware caused by respectively installing a single wave detector on the branch path can be avoided, meanwhile, the main path combined wave and the standby path combined wave for monitoring are continuously collected, and the judgment of whether the switching is needed or not is carried out again after the main path combined wave and the standby path combined wave do not need to be switched is carried out again after the judgment of a period of time T1, and the judgment of whether the switching condition is met or not carried out again after a period of time T1 is carried out every time when the judgment of the switching is carried out, and the continuous quality inspection of the main and standby paths in the wavelength division multiplexing application process is realized in a circulating manner, the main and standby paths are switched in real time, and the optimal main optical fiber line is continuously searched for carrying out remote optical wave transmission. Therefore, the device provided by the invention avoids the complex filtering processing requirement and also reduces the hardware cost.

On the basis of the above-described embodiment, in the apparatus,

if it is determined that the N main pilot signals and the N standby pilot signals satisfy the preset main-standby switching condition, performing main-standby protection switching processing, specifically including:

On the basis of the above-described embodiment, in the apparatus,

after the main/standby protection switching processing is performed, a second time duration T2 is preset at intervals, and whether the N main pilot signals and the N standby pilot signals meet the preset main/standby switching condition is judged again.

On the basis of the above-described embodiment, in the apparatus,

after the processing of the main path combined wave and the standby path combined wave by using low-pass filtering to obtain N main path pilot signals and N standby path pilot signals, the method further includes:

On the basis of the above-described embodiment, in the device,

the detecting and determining that the N main pilot signals and the N standby pilot signals correspond to correct pilot signals respectively added with corresponding pilot signals to the N far-end service signals further includes:

On the basis of the above-described embodiment, in the apparatus,

before judging whether the N main pilot signals and the N standby pilot signals satisfy the preset main-standby switching condition again, the method further includes:

On the basis of the above embodiments, the present invention further provides a protection switching system in wavelength division multiplexing application, which is characterized by comprising any one of the protection switching devices in wavelength division multiplexing application, a remote end device AAU, a local end device BBU, a remote end passive box, a local end multiplexer/demultiplexer device, a main/standby switch, a main duplex fiber and a standby duplex fiber, wherein,

Specifically, the present invention introduces all devices and apparatuses in a system implementing a protection switching method in wavelength division multiplexing applications. The local side device BBU is configured to perform electro-optical conversion on the local side N service signals to obtain N optical signals, send the N optical signals to the local side add/drop device to output local side transmit optical waves, where the output local side transmit optical waves pass through the main/standby switch to currently select a main path to send to the remote side device AAU, and perform wavelength-division processing when reaching the remote passive box, and output N local side service signals to be transmitted on corresponding N remote side service lines.

The system provided by the invention collects the standby combined wave of the transmitting light wave and the far-end returning light wave of the office end of the standby light inlet by continuously collecting the main-path combined wave of the transmitting light wave and the far-end returning light wave of the office end of the main-path light inlet; processing the main path composite wave and the standby path composite wave by using low-pass filtering to obtain N main path pilot signals and N standby path pilot signals; judging whether the N main pilot signals and the N standby pilot signals meet preset main-standby switching conditions or not, if so, sending a switching processing command to control a main-standby switching switch to switch the light path; if not, presetting a first time length T1 at intervals, and judging whether the N main road pilot signals and the N standby road pilot signals meet the preset main-standby switching condition again; the far-end return light waves on the main path and the standby path are obtained by respectively adding corresponding pilot signals to far-end N-path service signals, then carrying out electro-optical conversion and wave combination processing, and then respectively transmitting the signals to the main path light inlet and the standby path light inlet through the main path, wherein N is a positive integer. Because the pilot signal is inserted into each path of service signal at the far end, after the combined wave transmitted by the main path and the branch path from the far end is collected at the optical inlet of the local end, the optical-to-electrical conversion is carried out firstly, then the pilot signal is filtered out, and whether the protection switching processing is needed or not is judged according to the pilot signal of each far end service signal output by the main path and the standby path, so that the complex filtering processing of distinguishing the single wave signals of different service paths in the same end signal from the far end service signal and the local end service signal can be avoided, the high cost of the integrated hardware caused by respectively installing a single wave detector on the branch path can be avoided, meanwhile, the main path combined wave and the standby path combined wave for monitoring are continuously collected, and the judgment of whether the switching is needed or not is carried out again after the main path combined wave and the standby path combined wave do not need to be switched is carried out again after the judgment of a period of time T1, and the judgment of whether the switching condition is met or not carried out again after a period of time T1 is carried out every time when the judgment of the switching is carried out, and the continuous quality inspection of the main and standby paths in the wavelength division multiplexing application process is realized in a circulating manner, the main and standby paths are switched in real time, and the optimal main optical fiber line is continuously searched for remote optical wave transmission. Therefore, the system provided by the invention avoids the complex filtering processing requirement and also reduces the hardware cost.

Based on the foregoing embodiments, the present invention provides a protection switching operation flow in wavelength division multiplexing application, fig. 9 is a schematic diagram of the protection switching operation flow in wavelength division multiplexing application provided by the present invention, and as shown in fig. 9, the steps of the flow are as follows:

firstly, initializing equipment, namely electrifying a far-end module AAU and local-end equipment, then adding corresponding pilot frequencies to each far-end service signal by the far-end module, acquiring composite waves at an optical inlet by the local-end equipment, detecting and extracting the pilot frequencies on a main circuit and a standby circuit, entering judgment of a protection switching triggering condition through verification that whether a pilot frequency point corresponds to the pilot frequency of the far-end module correctly, if so, switching an optical switch to switch the main circuit to the standby circuit, and if not, waiting delta t₁After the time length is long, the jump enters the judgment of the protection switching triggering condition, and after the switch is switched to the standby path, the waiting delta t is also needed₂After the time length, skipping to enter the detection of the pilot frequency information and continuing to judge the protection switching triggering condition, and sequentially carrying out the protection switching triggering condition so as to realize uninterrupted real-time protection switching in the operation process.

Fig. 10 illustrates a physical structure diagram of an electronic device, and as shown in fig. 10, the electronic device may include: a processor (processor)1010, a communication Interface (Communications Interface)1020, a memory (memory)1030, and a communication bus 1040, wherein the processor 1010, the communication Interface 1020, and the memory 1030 communicate with each other via the communication bus 1040. Processor 1010 may invoke logic instructions in memory 1030 to perform a protection switching method in a wavelength division multiplexing application, the method comprising: continuously collecting main path composite waves of the light waves emitted by the local side of the main path light inlet and the far-end return light waves, and collecting standby path composite waves of the light waves emitted by the local side of the standby path light inlet and the far-end return light waves; processing the main path composite wave and the standby path composite wave by using low-pass filtering to obtain N main path pilot signals and N standby path pilot signals; judging whether the N main pilot signals and the N standby pilot signals meet preset main-standby switching conditions, if so, sending a switching processing command to control a main-standby switching switch to switch the light path; if not, presetting a first time length T1 at intervals, and judging whether the N main road pilot signals and the N standby road pilot signals meet the preset main-standby switching condition again; the far-end return light waves on the main path and the standby path are obtained by respectively adding corresponding pilot signals to far-end N-path service signals, then carrying out electro-optical conversion and wave combination processing, and then respectively transmitting the signals to the main path light inlet and the standby path light inlet through the main path, wherein N is a positive integer.

Furthermore, the logic instructions in the memory 1030 can be implemented in software functional units and stored in a computer readable storage medium when the logic instructions are sold or used as independent products. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

In another aspect, the present invention also provides a computer program product, which includes a computer program stored on a non-transitory computer readable storage medium, the computer program including program instructions, when the program instructions are executed by a computer, the computer being capable of executing the protection switching method in the wavelength division multiplexing application provided by the above methods, the method including: continuously collecting main path composite waves of the light waves emitted by the local side of the main path light inlet and the far-end return light waves, and collecting standby path composite waves of the light waves emitted by the local side of the standby path light inlet and the far-end return light waves; processing the main path composite wave and the standby path composite wave by using low-pass filtering to obtain N main path pilot signals and N standby path pilot signals; judging whether the N main pilot signals and the N standby pilot signals meet preset main-standby switching conditions, if so, sending a switching processing command to control a main-standby switching switch to switch the light path; if not, presetting a first time length T1 at intervals, and judging whether the N main road pilot signals and the N standby road pilot signals meet the preset main-standby switching condition again; the far-end return light waves on the main path and the standby path are obtained by respectively adding corresponding pilot signals to far-end N-path service signals, then carrying out electro-optical conversion and wave combination processing, and then respectively transmitting the signals to the main path light inlet and the standby path light inlet through the main path, wherein N is a positive integer.

In still another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored, the computer program, when being executed by a processor, is implemented to perform the protection switching method in the wavelength division multiplexing application provided by the above methods, the method including: continuously collecting main path composite waves of the light waves emitted by the local side of the main path light inlet and the far-end return light waves, and collecting standby path composite waves of the light waves emitted by the local side of the standby path light inlet and the far-end return light waves; processing the main path composite wave and the standby path composite wave by using low-pass filtering to obtain N main path pilot signals and N standby path pilot signals; judging whether the N main pilot signals and the N standby pilot signals meet preset main-standby switching conditions, if so, sending a switching processing command to control a main-standby switching switch to switch the light path; if not, presetting a first time length T1 at intervals, and judging whether the N main road pilot signals and the N standby road pilot signals meet the preset main-standby switching condition again; the far-end return light waves on the main path and the standby path are obtained by respectively adding corresponding pilot signals to far-end N-path service signals, then carrying out electro-optical conversion and wave combination processing, and then respectively transmitting the signals to the main path light inlet and the standby path light inlet through the main path, wherein N is a positive integer.

The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A protection switching method in wavelength division multiplexing application is characterized by comprising the following steps:

2. The protection switching method in wdm application according to claim 1, wherein if it is determined that the N main pilot signals and the N backup pilot signals satisfy a preset main-backup switching condition, performing main-backup protection switching processing specifically includes:

3. The protection switching method in wavelength division multiplexing application according to claim 2, wherein after the active/standby protection switching processing is performed, a preset second time duration T2 is set at an interval, and whether the N main pilot signals and the N standby pilot signals satisfy a preset active/standby switching condition is determined again.

4. The protection switching method according to claim 3, wherein after the processing the primary and backup combined waves by using low-pass filtering to obtain N primary pilot signals and N backup pilot signals, the method further comprises:

5. The protection switching method in wavelength division multiplexing application according to claim 4, wherein the detecting and determining that the N main path pilot signals and the N standby path pilot signals all correspond to the pilot signals corresponding to the respective N far-end traffic signals added by the corresponding pilot signals further comprises:

6. The protection switching method in wavelength division multiplexing application according to claims 1-5, wherein before determining again whether the N main pilot signals and N standby pilot signals satisfy the preset main/standby switching conditions, further comprising:

7. A protection switching device in wavelength division multiplexing applications, comprising:

the low-pass filtering unit is used for processing the main path combined wave and the standby path combined wave by using low-pass filtering to obtain N main path pilot signals and N standby path pilot signals;

8. A protection switching system in WDM application, which comprises the protection switching device in WDM application of claim 7, remote end equipment AAU, local end equipment BBU, remote passive box, local end multiplexer/demultiplexer, main/standby switch, main/standby duplex fiber and standby duplex fiber,

9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the steps of the protection switching method in a wavelength division multiplexing application according to any one of claims 1 to 6 when executing the program.

10. A non-transitory computer-readable storage medium, on which a computer program is stored, wherein the computer program, when executed by a processor, implements the steps of the protection switching method in a wavelength division multiplexing application according to any of claims 1 to 6.