Method and system for positioning optical multipath interference

Abstract

The invention provides a method and system for positioning optical multipath interference, and the method comprises the steps: obtaining noise after a signal is collected at an interval of a specified sample number or at an interval of specified time, carrying out the related operation of the collected signal and noise, or carrying out the periodic accumulation of the signal and noise, and carrying out the related operation to obtain a relative delay sample number, thereby achieving the positioning of the optical multipath interference. The absolute delay sample number is calculated by changing the superposition period, and the delay time of the MPI path relative to the signal is obtained, so that the required storage space is greatly reduced, and accurate MPI positioning is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of positioning optical multipath interference, and in particular to a method and system for positioning optical multipath interference. Background Art

[0002] In optical fiber links, there is often multipath interference (MPI), which refers to the interference caused by the optical signal reflecting back and forth between the optical fiber connection points. If the MPI is too large, it is easy to cause the bit error rate to increase or even communication interruption.

[0003] Patent document CN118233018A discloses a method for locating MPI and related equipment, which are used to locate the position where MPI appears in the optical fiber link. The method includes: the MCU obtains the first noise signal according to the signal output by the equalizer, the MCU determines the positive and negative signs of the jump window average value of the first noise signal, the MCU multiplies the first noise signal by the positive and negative signs to obtain the second noise signal, and the MCU determines the reflection distance according to the second noise signal, and the reflection distance is used to indicate the distance between the two optical fiber connection points that cause MPI in the optical fiber link. However, for longer optical links, the patent requires that the DSP chip or MCU store the cross-correlation operation results of up to 1e6 to 1e7 orders of magnitude, which is a great challenge to the storage space of the DSP chip or MCU. In addition, the patent proposes to send two periodic sequences and use the sequence and noise to do cross-correlation to locate MPI. However, this method requires sending a special periodic sequence and cannot be implemented based on the service signal, which means that the service needs to be interrupted, or the periodic sequence needs to be sent additionally while sending the service information. Summary of the invention

[0004] In view of the defects in the prior art, an object of the present invention is to provide a method and system for locating optical multipath interference.

[0005] The method for locating optical multipath interference provided by the present invention comprises:

[0006] Step 11: Calculate all reflection paths using known link topology information and the receiver sampling rate;

[0007] Step 12: Determine the number of interval samples or the interval time required to collect the signal and the noise by delaying the number of samples or the delay time;

[0008] Step 13: first collect a section of signal as the required signal, and then collect the noise corresponding to the section of signal as the required noise after a preset interval time or a preset number of interval samples;

[0009] Step 14: Processing the collected signal and noise separately, including removing DC from the signal, calculating noise power through the noise and removing DC;

[0010] Step 15: Perform a cross-correlation operation on the processed signal and the noise, and the position of the correlation peak indicates the relative delayed sample number or relative delayed time of the noise relative to the signal;

[0011] Step 16: Calculate the number of delayed samples or the delay time of the MPI path relative to the signal by collecting the number of interval samples or the interval time required for the signal and the noise, and the number of relative delayed samples or the relative delay time of the noise relative to the signal;

[0012] Step 17: Based on the number of delay samples or delay time of the MPI path relative to the signal, a list of the number of delay samples or delay time experienced by all reflection paths relative to the signal in the known link topology information is compared, and the matching reflection path is the detected reflection path, thereby locating the corresponding reflection point.

[0013] Preferably, for any two reflection points at known positions in the known link topology information, the number of delayed samples or the delay time experienced by the formed reflection path relative to the signal is calculated as:

[0014] Number of delayed samples = distance between reflection points × 2 × sampling rate ÷ speed of light in optical fiber;

[0015] Delay time = distance between reflection points × 2 ÷ speed of light in optical fiber.

[0016] Preferably, the acquisition of the noise includes: acquiring a decision signal using an equalizer output signal corresponding to the second segment signal, and then subtracting the decision signal from the equalizer output signal to acquire the noise.

[0017] The method for locating optical multipath interference provided by the present invention comprises:

[0018] Step 21: Collect signals and noise;

[0019] Step 22: Processing the signal and the noise respectively, including removing DC from the signal, calculating power through the noise and removing DC;

[0020] Step 23: performing periodic accumulation on the processed signal and noise according to a specified accumulation period to obtain a periodic accumulated signal and a periodic accumulated noise;

[0021] Step 24: performing correlation operation on the periodically accumulated signal and the periodically accumulated noise to obtain a correlation result;

[0022] Step 25: Repeat steps 22 to 24 for multiple times, and accumulate the correlation results obtained each time until a clear correlation peak appears in the accumulated sum of the correlation results, and use the correlation peak to read out the relative delayed sample number of the periodically accumulated noise relative to the periodically accumulated signal;

[0023] Step 26: Change the designated accumulation period used for periodic accumulation, repeat steps 22 to 25, and determine the delay time of the MPI path relative to the signal through different designated accumulation periods and their corresponding relative delay sample numbers and the Chinese remainder theorem;

[0024] Step 27: Determine a corresponding reflection point according to the delay time of the MPI path relative to the signal and in combination with link topology information.

[0025] Preferably, the noise acquisition comprises: acquiring a decision signal through a signal output by an equalizer, and then acquiring the noise by subtracting the decision signal from the signal output by the equalizer.

[0026] The system for locating optical multipath interference provided by the present invention comprises:

[0027] Module M11: Calculate all reflection paths based on known link topology information and receiver sampling rate;

[0028] Module M12: Determines the number of interval samples or the interval time required for collecting signals and noise by delaying the number of samples or the delay time;

[0029] Module M13: first collect a section of signal as the required signal, and then collect the noise corresponding to the section of signal as the required noise after a preset interval time or a preset number of interval samples;

[0030] Module M14: Processing the collected signal and noise separately, including removing DC from the signal, calculating the noise power through the noise and removing DC;

[0031] Module M15: performing cross-correlation operation on the processed signal and noise, and the position of the correlation peak indicates the relative delay sample number or relative delay time of the noise relative to the signal;

[0032] Module M16: Calculate the number of delayed samples or the delay time of the MPI path relative to the signal by collecting the number of interval samples or the interval time required for the signal and the noise, and the number of relative delayed samples or the relative delay time of the noise relative to the signal;

[0033] Module M17: According to the number of delay samples or delay time of the MPI path relative to the signal, a list of the number of delay samples or delay time experienced by all reflection paths relative to the signal in the known link topology information is compared, and the matching reflection path is the detected reflection path, thereby locating the corresponding reflection point.

[0034] Preferably, for any two reflection points at known positions in the known link topology information, the number of delayed samples or the delay time experienced by the formed reflection path relative to the signal is calculated as:

[0035] Number of delayed samples = distance between reflection points × 2 × sampling rate ÷ speed of light in optical fiber;

[0036] Delay time = distance between reflection points × 2 ÷ speed of light in optical fiber.

[0037] Preferably, the acquisition of the noise includes: acquiring a decision signal using an equalizer output signal corresponding to the second segment signal, and then subtracting the decision signal from the equalizer output signal to acquire the noise.

[0038] The system for locating optical multipath interference provided by the present invention comprises:

[0039] Module M21: collect signals and noise;

[0040] Module M22: processing the signal and the noise respectively, including removing DC from the signal, calculating power through the noise and removing DC;

[0041] Module M23: performing periodic accumulation on the processed signal and noise according to a specified accumulation period to obtain a periodic accumulated signal and a periodic accumulated noise;

[0042] Module M24: performing correlation operation on the periodically accumulated signal and the periodically accumulated noise to obtain a correlation result;

[0043] Module M25: repeatedly triggering modules M22 to M24 for multiple times, and accumulating the correlation results obtained each time, until a clear correlation peak appears in the accumulation of the correlation results, and using the correlation peak to read out the relative delayed sample number of the periodically accumulated noise relative to the periodically accumulated signal;

[0044] Module M26: Change the specified accumulation period used for periodic accumulation, repeatedly trigger modules M22 to M25, and determine the delay time of the MPI path relative to the signal through different specified accumulation periods and their corresponding relative delay sample numbers and the Chinese remainder theorem;

[0045] Module M27: Determine a corresponding reflection point according to the delay time of the MPI path relative to the signal and in combination with link topology information.

[0046] Preferably, the noise acquisition comprises: acquiring a decision signal through a signal output by an equalizer, and then acquiring the noise by subtracting the decision signal from the signal output by the equalizer.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] (1) The present invention processes the received service signal to obtain the signal and the noise, without sending a special periodic sequence or a special code type, thereby achieving the effect of not interrupting the service;

[0049] (2) Solution 1 of the present invention achieves the effect of greatly reducing the requirement for storage space by first storing the shorter signal, then storing the noise of the same or equivalent length after a fixed number of symbols (or a fixed time, or a fixed number of bits).

[0050] (3) Solution 2 of the present invention achieves the effect of greatly reducing the requirement for storage space size by performing periodic accumulation operations on the processed signal and noise according to a specified accumulation period. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0052] Figure 1 Flowcharts of the first and second invention schemes;

[0053] Figure 2 This is a specific implementation example of Scheme 2 of the present invention. DETAILED DESCRIPTION

[0054] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0055] Example

[0056] like Figure 1 and Figure 2 The present invention provides a method for locating optical multipath interference, comprising:

[0057] Option 1:

[0058] Step 1: Calculate the number of delayed samples (or delay time) experienced by the signal for all possible reflection paths using the known link topology information and the sampling rate of the receiver. For any two reflection points at known positions in the known link topology information, the number of delayed samples (or delay time) experienced by the reflection paths they may form relative to the signal can be calculated as:

[0059] Number of delayed samples = distance between reflection points × 2 × sampling rate ÷ speed of light in optical fiber.

[0060] Delay time = distance between reflection points × 2 ÷ speed of light in optical fiber.

[0061] Step 2: Determine the number of interval samples (or interval time) required for collecting signals and noise through the number of delayed samples (or delay time). There is no strict size relationship between the number of interval samples (or interval time) and the number of delayed samples (or delay time) (which can be determined according to specific implementation conditions), but the two should be close to ensure that in the subsequent steps, in the two signals collected successively with the number of interval samples (or interval time), the length of the partial sequence showing correlation accounts for a large enough proportion of the total length of the collected signal sequence.

[0062] Step 3: first collect a segment of signal as the collected signal, and then collect the noise corresponding to another segment of signal as the noise after the interval time or the interval sample number. The noise is obtained by obtaining a decision signal using the equalizer output signal corresponding to the second segment of signal, and then subtracting the decision signal from the signal output by the equalizer to obtain the noise.

[0063] Step 4: Perform certain processing on the signal and the noise respectively, for example (but not limited to) removing the DC from the signal, calculating the noise power through the noise and removing the DC.

[0064] Step 5: Perform a cross-correlation operation on the signal and noise after the above processing, and the position of the correlation peak indicates the relative delayed sample number (or relative delayed time) of the noise relative to the signal.

[0065] Step 6: Calculate the number of delayed samples (or delay time) of the MPI path relative to the signal by using the number of interval samples (or interval time) required to acquire the signal and noise, and the number of relative delayed samples (or relative delay time) of the noise relative to the signal.

[0066] Step 7: Based on the number of delay samples (or delay time) of the MPI path relative to the signal, a list of all possible reflection paths in the known link topology information relative to the number of delay samples (or delay time) experienced by the signal is compared, and the matching reflection path is the detected reflection path, thereby locating the corresponding reflection point.

[0067] Option 2:

[0068] Step 1: Collect signals and noises. The noise is obtained by obtaining a decision signal through a signal output by an equalizer, and then obtaining noise by subtracting the decision signal from the signal output by the equalizer.

[0069] Step 2: Perform certain processing on the signal and the noise respectively, for example (but not limited to) removing the DC from the signal, calculating the power through the noise and removing the DC.

[0070] Step 3: For the signal and noise processed as above, periodic accumulation is performed respectively according to a specified accumulation period to obtain a periodic accumulated signal and a periodic accumulated noise.

[0071] Step 4: Perform a correlation operation (such as but not limited to cyclic correlation) on the periodically accumulated signal and the periodically accumulated noise to obtain a correlation result.

[0072] Step 5: Repeat steps 2 to 4 above multiple times, and accumulate the correlation results obtained each time until a clear correlation peak appears in the cumulative sum of the correlation results, and use the correlation peak to read the relative delayed sample number of the periodically accumulated noise relative to the periodically accumulated signal.

[0073] Step 6: Change the specified accumulation period used for periodic accumulation, and repeat the above steps 2 to 5. Determine the delay time of the MPI path relative to the signal through different specified accumulation periods and their corresponding relative delay sample numbers and the Chinese remainder theorem.

[0074] Step 7: Determine a corresponding reflection point according to the delay time of the MPI path relative to the signal and in combination with link topology information.

[0075] Those skilled in the art know that, in addition to implementing the system, device and its various modules provided by the present invention in a purely computer-readable program code, it is entirely possible to implement the same program in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers and embedded microcontrollers by logically programming the method steps. Therefore, the system, device and its various modules provided by the present invention can be considered as a hardware component, and the modules included therein for implementing various programs can also be considered as structures within the hardware component; the modules for implementing various functions can also be considered as both software programs for implementing the method and structures within the hardware component.

[0076] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A method for locating optical multipath interference, characterized in that: include: Step 11: Calculate all reflection paths using known link topology information and the receiver sampling rate; Step 12: Determine the number of interval samples or the interval time required to collect the signal and the noise by delaying the number of samples or the delay time; Step 13: first collect a section of signal as the required signal, and then collect the noise corresponding to the section of signal as the required noise after a preset interval time or a preset number of interval samples; Step 14: Processing the collected signal and noise separately, including removing DC from the signal, calculating noise power through the noise and removing DC; Step 15: Perform a cross-correlation operation on the processed signal and the noise, and the position of the correlation peak indicates the relative delayed sample number or relative delayed time of the noise relative to the signal; Step 16: Calculate the number of delayed samples or the delay time of the MPI path relative to the signal by collecting the number of interval samples or the interval time required for the signal and the noise, and the number of relative delayed samples or the relative delay time of the noise relative to the signal; Step 17: Based on the number of delay samples or delay time of the MPI path relative to the signal, a list of the number of delay samples or delay time experienced by all reflection paths relative to the signal in the known link topology information is compared, and the matching reflection path is the detected reflection path, thereby locating the corresponding reflection point.

2. The method for locating optical multipath interference according to claim 1, characterized in that: For any two reflection points at known locations in the known link topology information, the number of delayed samples or delay time experienced by the reflected path relative to the signal is calculated as: Number of delayed samples = distance between reflection points × 2 × sampling rate ÷ speed of light in optical fiber; Delay time = distance between reflection points × 2 ÷ speed of light in optical fiber.

3. The method for locating optical multipath interference according to claim 1, characterized in that: The acquisition of the noise includes: acquiring a decision signal using an equalizer output signal corresponding to the second segment signal, and then subtracting the decision signal from the equalizer output signal to acquire the noise.

4. A method for locating optical multipath interference, characterized in that: include: Step 21: Collect signals and noise; Step 22: Processing the signal and the noise respectively, including removing DC from the signal, calculating power through the noise and removing DC; Step 23: performing periodic accumulation on the processed signal and noise according to a specified accumulation period to obtain a periodic accumulated signal and a periodic accumulated noise; Step 24: performing correlation operation on the periodically accumulated signal and the periodically accumulated noise to obtain a correlation result; Step 25: Repeat steps 22 to 24 for multiple times, and accumulate the correlation results obtained each time until a clear correlation peak appears in the accumulated sum of the correlation results, and use the correlation peak to read out the relative delayed sample number of the periodically accumulated noise relative to the periodically accumulated signal; Step 26: Change the designated accumulation period used for periodic accumulation, repeat steps 22 to 25, and determine the delay time of the MPI path relative to the signal through different designated accumulation periods and their corresponding relative delay sample numbers and the Chinese remainder theorem; Step 27: Determine a corresponding reflection point according to the delay time of the MPI path relative to the signal and in combination with link topology information.

5. The method for locating optical multipath interference according to claim 4, characterized in that: The acquisition of the noise includes: acquiring a decision signal through a signal output by an equalizer, and then subtracting the decision signal from the signal output by the equalizer to acquire the noise.

6. A system for locating optical multipath interference, characterized in that: include: Module M11: Calculate all reflection paths based on known link topology information and receiver sampling rate; Module M12: Determines the number of interval samples or the interval time required for collecting signals and noise by delaying the number of samples or the delay time; Module M13: first collect a section of signal as the required signal, and then collect the noise corresponding to the section of signal as the required noise after a preset interval time or a preset number of interval samples; Module M14: Processing the collected signal and noise separately, including removing DC from the signal, calculating the noise power through the noise and removing DC; Module M15: performing cross-correlation operation on the processed signal and noise, and the position of the correlation peak indicates the relative delay sample number or relative delay time of the noise relative to the signal; Module M16: Calculate the number of delayed samples or the delay time of the MPI path relative to the signal by collecting the number of interval samples or the interval time required for the signal and the noise, and the number of relative delayed samples or the relative delay time of the noise relative to the signal; Module M17: According to the number of delay samples or delay time of the MPI path relative to the signal, a list of the number of delay samples or delay time experienced by all reflection paths relative to the signal in the known link topology information is compared, and the matching reflection path is the detected reflection path, thereby locating the corresponding reflection point.

7. The system for locating optical multipath interference according to claim 6, characterized in that: For any two reflection points at known locations in the known link topology information, the number of delayed samples or delay time experienced by the reflected path relative to the signal is calculated as: Number of delayed samples = distance between reflection points × 2 × sampling rate ÷ speed of light in optical fiber; Delay time = distance between reflection points × 2 ÷ speed of light in optical fiber.

8. The system for locating optical multipath interference according to claim 6, characterized in that: The acquisition of the noise includes: acquiring a decision signal using an equalizer output signal corresponding to the second segment signal, and then subtracting the decision signal from the equalizer output signal to acquire the noise.

9. A system for locating optical multipath interference, characterized in that: include: Module M21: collect signals and noise; Module M22: processing the signal and the noise respectively, including removing DC from the signal, calculating power through the noise and removing DC; Module M23: performing periodic accumulation on the processed signal and noise according to a specified accumulation period to obtain a periodic accumulated signal and a periodic accumulated noise; Module M24: performing correlation operation on the periodically accumulated signal and the periodically accumulated noise to obtain a correlation result; Module M25: repeatedly triggering modules M22 to M24 for multiple times, and accumulating the correlation results obtained each time, until a clear correlation peak appears in the accumulation of the correlation results, and using the correlation peak to read out the relative delayed sample number of the periodically accumulated noise relative to the periodically accumulated signal; Module M26: Change the specified accumulation period used for periodic accumulation, repeatedly trigger modules M22 to M25, and determine the delay time of the MPI path relative to the signal through different specified accumulation periods and their corresponding relative delay sample numbers and the Chinese remainder theorem; Module M27: Determine a corresponding reflection point according to the delay time of the MPI path relative to the signal and in combination with link topology information.

10. The system for locating optical multipath interference according to claim 9, characterized in that: The acquisition of the noise includes: acquiring a decision signal through a signal output by an equalizer, and then subtracting the decision signal from the signal output by the equalizer to acquire the noise.

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