Estimation device and estimation method

Abstract

An estimation device 10 comprises: a storage unit 13 that stores a wavelength dependency reference; an input unit 11 to which an OSNR measurement value measured in an empty channel different from a channel to be investigated is input; and an estimation unit 12 that estimates the OSNR of the channel to be investigated on the basis of a deviation of the OSNR measurement value in the empty channel from the reference value and the reference value of the channel to be investigated.

Description

Estimation device and estimation method 【0001】 This disclosure relates to an estimation device and an estimation method. 【0002】 Optical transmission networks are the infrastructure that supports a wide variety of services and applications. Managing communication quality plays a crucial role in improving network reliability. 【0003】 One representative indicator used to evaluate the communication quality of optical transmission networks is the Optical Signal to Noise Ratio (OSNR), which is used to evaluate signal quality. Non-patent document 1 describes a system in which OSNR monitors are placed at each relay point of an optical transmission network, enabling monitoring and understanding of the quality at each relay point. 【0004】 Hiroshi Shibata, et al., "A Study on Improving the Accuracy of Estimating Quality Anomaly Sections in Optical Communication Relay Networks," IEICE General Conference 2024, B-6-55 【0005】 To determine OSNR in an in-service state without interrupting optical communication service, it is necessary to split the optical signal and input a portion of it to the OSNR monitor. This splitting reduces the signal power, potentially negatively impacting communication quality. 【0006】 This disclosure is made in view of the above and aims to estimate OSNR without affecting communication quality. 【0007】 An estimation device according to one aspect of the present disclosure includes a storage unit that holds a reference value of the optical signal-to-noise ratio for each channel in a relay section; an input unit that inputs a measured value of the optical signal-to-noise ratio measured in an unused channel other than the channel under investigation; and an estimation unit that estimates the optical signal-to-noise ratio of the channel under investigation from the deviation of the measured value in the unused channel from the reference value and the reference value of the channel under investigation. 【0008】 According to this disclosure, OSNR can be estimated without affecting communication quality. 【0009】Figure 1 shows an example of the configuration of the estimation device and the optical communication relay network. Figure 2 shows an example of a wavelength-dependent reference. Figure 3 is a diagram illustrating how to obtain the estimated value using the wavelength-dependent reference. Figure 4 is a flowchart illustrating an example of the OSNR estimation process flow. Figure 5 shows an example of an optical communication relay network composed of multiple optical transmission devices with different wavelength-dependent tendencies. Figure 6 is a flowchart illustrating an example of the OSNR estimation process flow. Figure 7 shows an example of a reference model composed only of relay nodes. Figure 8 shows an example of a reference model composed only of amplifiers. Figure 9 shows an example of a wavelength-dependent reference for a relay node obtained using the reference model in Figure 7. Figure 10 shows an example of a wavelength-dependent reference for an amplifier obtained using the reference model in Figure 8. Figure 11 shows an example of a reference model with amplifiers placed between relay nodes. Figure 12 shows an example of a wavelength-dependent reference obtained using the reference model in Figure 11. Figure 13 shows the measurement of the OSNR of the optical communication relay network in Figure 5. Figure 14 is a diagram illustrating how to obtain the estimated value using the wavelength-dependent reference of the relay section obtained by synthesis. Figure 15 shows an example of the hardware configuration of the estimation device. 【0010】 [Optical Communication Relay Network] Referring to Figure 1, an example of the configuration of an optical communication relay network and an example of the configuration of the estimation device 10 will be described. 【0011】 In an optical communication relay network, an optical wavelength path is established between an optical transmitter 110 and an optical receiver 120 via a relay node 130. Each device is connected by an optical fiber 100. By using wavelength division multiplexing (WDM), it becomes possible to transmit large amounts of data using multiple wavelengths (also called channels) on a single optical fiber. 【0012】 For example, the optical transmitter 110 and the optical receiver 120 each function as an All Photonics Network - Transceiver (APN-T) and are transceivers that constitute the endpoints of the optical wavelength path. 【0013】For example, relay node 130 functions as an All Photonics Network - Gateway (APN-G) and is a Reconfigurable Optical Add / Drop Multiplexer (ROADM) that relays optical wavelength paths. Relay node 130 includes a Pseudo Wave (PW) light source 131 that emits pseudo light and a monitor 132 that measures the optical power of the pseudo light. The PW light source 131 and monitor 132 serve the channel (wavelength λ) in service. S ) rather than an empty channel (wavelength λ T The OSNR value of the relay section is measured using the ON / OFF method. The ON / OFF method is a method of calculating the OSNR by measuring the sum of the signal optical power and noise power when the optical signal is ON, and measuring the optical power of the noise component when the optical signal is OFF. Wavelength λ S and different wavelengths λ T Since it uses an optical signal, the OSNR can be measured without affecting the channel in service. The pseudo-light function of ROADM can be used for the PW light source 131 and the monitor 132. Alternatively, an OSNR monitor used in Non-Patent Document 1, which converts the optical signal to an electrical signal, measures the high-frequency component power of the electrical signal, and converts it to an OSNR value, may be used. 【0014】 The OSNR value measured using an unused channel differs from the OSNR value of a channel in service due to wavelength dependence. Therefore, the estimation device 10 estimates the OSNR of the channel in service based on the deviation of the OSNR measurement value on the unused channel from the wavelength-dependent reference. Wavelength dependence refers to the phenomenon where the gain and noise amount of the optical signal power differ depending on the wavelength. When multiple optical signals of different wavelengths are transmitted simultaneously through a single optical fiber, each wavelength may be affected by different characteristics from the optical transmission equipment on the transmission path. The wavelength-dependent reference is a reference value (also called a normal value or reference value) of OSNR for each wavelength in an optical communication relay network, and is acquired in advance in the experimental environment. 【0015】[Estimation Device] The estimation device 10 shown in Figure 1 comprises an input unit 11, an estimation unit 12, and a storage unit 13. The estimation device 10 receives OSNR values ​​measured using idle channels in an optical communication relay network in actual operation (hereinafter also referred to as the commercial environment), and estimates the OSNR of a channel in service (hereinafter also referred to as the channel under investigation) by considering the difference in OSNR between channels due to wavelength dependence. 【0016】 The input unit 11 receives the OSNR value measured on an available channel in the relay section of the optical communication relay network. 【0017】 The estimation unit 12 estimates the OSNR of the channel under investigation by considering the wavelength-dependent reference held by the memory unit 13 and the deviation (also called the degree of degradation) of the OSNR measurement value in the unused channel from the reference value. 【0018】 The memory unit 13 holds a wavelength-dependent reference. The OSNR is measured in advance for each channel (wavelength) and used as the wavelength-dependent reference for the relay node 130. For example, in creating the wavelength-dependent reference, as shown in Figure 1, the OSNR for each channel is measured using the ON / OFF method with the PW light source 131 and the monitor 132. The OSNR may also be measured using the optical signal from the optical transmitter 110. The memory unit 13 holds the measured OSNR value for each channel (hereinafter referred to as the reference value) as the wavelength-dependent reference. The reference value may also be measured using an optical communication relay network in an experimental environment prepared separately from the commercial environment. Optical transmission equipment such as the relay node 130 used to measure the reference value should be in working order and in a normal state. 【0019】 Figure 2 shows an example of a wavelength-dependent reference. The example in Figure 2 shows OSNR measurements obtained for nine channels between 1530 nm and 1565 nm. Note that, for simplicity of explanation, Figure 2 shows the wavelength-dependent reference in the case where the graph is a straight line. 【0020】The reference value is a standard of the OSNR in a normal state. When an abnormality occurs in an optical transmission device or the like, the OSNR value deteriorates compared to the reference value. The estimation device 10 estimates the OSNR of the investigation target channel from the degree of deterioration from the reference value of the OSNR measurement value in the idle channel. 【0021】 Referring to FIG. 3, an example of estimating the OSNR of the investigation target channel using the wavelength-dependent reference will be described. For the measurement value OSNR(λ T ) in the idle channel (wavelength λ T ), the calculation of the estimated value OSNR(λ S ) in the investigation target channel (wavelength λ S ) is performed using the following formula. 【0022】 【0023】 Here, OSNR ref (λ S ) is the reference value at wavelength λ S , and OSNR ref (λ T ) is the reference value at wavelength λ T . For example, when the reference value and the measurement value are OSNR ref (λ S ) = 19.3 dB, OSNR ref (λ T ) = 19.8 dB, and OSNR(λ T ) = 19.5 dB, the estimated value OSNR(λ S ) = 19.0 dB. Note that the calculation is performed using the true value instead of the dB value. The same applies to the subsequent calculations. 【0024】 [OSNR Estimation Process] Referring to the flowchart of FIG. 4, an example of the OSNR estimation process will be described. 【0025】In step S1, the wavelength dependence reference of the OSNR of the relay node 130 is measured. For example, in an experimental environment, an optical communication relay network is constructed using a relay node 130 equivalent to a commercial environment, and the OSNR is measured for each wavelength by the ON / OFF method using the PW light source 131 and the monitor 132 provided in the relay node 130. The measurement results of the OSNR for each wavelength are stored in the estimation device 10 as the wavelength dependence reference. 【0026】 Step S1 is a preliminary preparation and is carried out at least once to store the wavelength dependence reference in the estimation device 10. After the preliminary preparation, in a commercial environment, the following processes of steps S2 and S3 are continuously carried out. 【0027】 In step S2, in a commercial environment, the OSNR value of an idle channel is obtained by the ON / OFF method for a channel that is not in service. The OSNR value of the idle channel is measured using the PW light source 131 and the monitor 132 provided in the relay node 130 of the commercial environment. 【0028】 In step S3, the estimation device 10 estimates the OSNR value of the investigation target channel from the OSNR measurement value. Specifically, the estimation device 10 inputs the OSNR measurement value, reads out the reference value of the idle channel and the reference value of the investigation target channel, and estimates the OSNR of the investigation target channel using the above-mentioned calculation formula. 【0029】 Since the OSNR value is measured for an idle channel, branching of the optical signal of the channel in service becomes unnecessary, and as a result, the OSNR of the channel in service can be estimated without affecting the quality. 【0030】 [Application to a complex network configuration] In the optical communication relay network of FIG. 5, an optical wavelength path is constructed between the optical transmission device 110 and the optical reception device 120 via four relay nodes 130 and three amplifiers 140. For example, the amplifier 140 functions as an All Photonics Network - Interchange (APN-I) and is an In-Line Amplifier (ILA) that amplifies an optical signal. Since the built-in amplifiers in the ROADM and the ILA are different, the wavelength dependence tendencies may be different. 【0031】 To create a wavelength-dependent reference, it is difficult to construct a relay network with the same configuration as the complex network configuration shown in Figure 5, which includes numerous optical transmitters, in an experimental environment. 【0032】 In this embodiment, a wavelength-dependent reference for an optical communication relay network of any network configuration is created by measuring reference values ​​with a simple configuration and synthesizing the measured reference values. 【0033】 Referring to the flowchart in Figure 6, an example of OSNR estimation processing in a complex network configuration will be explained. 【0034】 In step S11, a simple optical communication relay network is constructed for each optical transmission device (e.g., ROADM or ILA), and a reference value is measured for each optical transmission device. Figure 7 shows an example of a reference model consisting only of relay nodes 130, and Figure 8 shows an example of a reference model consisting only of amplifiers 140. In step S11, an optical communication relay network is constructed in the experimental environment with the respective configurations of the reference models in Figures 7 and 8, and the reference values ​​of the relay nodes 130 and amplifiers 140 are measured. Figure 9 shows an example of the wavelength-dependent reference of the relay node 130 obtained using the reference model in Figure 7, and Figure 10 shows an example of the wavelength-dependent reference of the amplifier 140 obtained using the reference model in Figure 8. 【0035】 If the amplifier 140 does not have an OSNR measurement function, an optical communication relay network is constructed with the amplifier 140 placed between relay nodes 130 capable of measuring OSNR, as shown in Figure 11, and a reference value including the relay nodes 130 and the amplifier 140 is measured. Figure 12 shows an example of a wavelength-dependent reference for a configuration including the relay nodes 130 and the amplifier 140 obtained using the reference model in Figure 11. 【0036】By subtracting the wavelength-dependent reference obtained for a configuration including only the relay node 130 (Figure 9) from the wavelength-dependent reference obtained for a configuration including the relay node 130 and the amplifier 140 (Figure 12), the wavelength-dependent reference for a configuration including only the amplifier 140 (Figure 10) can be obtained. Wavelength-dependent reference OSNR for amplifier 140 only ILA (λ) is the wavelength-dependent reference OSNR of a configuration including relay node 130 and amplifier 140. ROADM+ILA (λ) and the wavelength-dependent reference OSNR of relay node 130 ROADM Using (λ), it can be calculated using the following formula. 【0037】 【0038】 The wavelength-dependent reference for each optical transmission device is stored in the estimation device 10. 【0039】 In step S12, the estimation device 10 synthesizes and creates a wavelength-dependent reference for an optical communication relay network with an arbitrary network configuration. For example, the estimation device 10 takes the number of optical transmission devices in the optical communication relay network as input, and synthesizes a wavelength-dependent reference for each optical transmission device according to the number of optical transmission devices to create a total wavelength-dependent reference for the optical communication relay network. 【0040】 SNR -1 Since it is additive, the total wavelength-dependent reference OSNR of a relay section equipped with M relay nodes 130 and N amplifiers 140 TOTALref (λ) can be found using the following formula. 【0041】 【0042】 Note that the wavelength-dependent reference obtained using the reference model in Figure 7 is the wavelength-dependent reference for two relay nodes 130, so the number of relay nodes 130 M is divided by 2. 【0043】 The optical communication relay network shown in Figure 5 has four relay nodes 130 and three amplifiers 140 in the relay section. Therefore, with M=4 for the number of relay nodes 130 and N=3 for the number of amplifiers 140, the wavelength-dependent reference for the relay section in Figure 5 can be calculated. 【0044】 Steps S11 and S12 are preliminary steps, which are performed at least once to store the wavelength-dependent reference for the relay section in the estimation device 10. After the preliminary steps, the subsequent steps S21 and S31 are carried out continuously in the commercial environment. 【0045】 In step S21, the OSNR value is measured in an empty channel, similar to step S2 in Figure 4. For example, as shown in Figure 13, an empty channel (wavelength λ T At the relay node 130 to which the optical transmitter 110 is connected, pseudo-light is emitted from the PW light source 131, and the optical power is measured by the monitor 132 at the relay node 130 to which the optical receiver 120 is connected, and the OSNR value of the relay section is measured. 【0046】 In step S31, the estimation device 10 estimates the OSNR value of the channel under investigation from the OSNR measurement value. This differs from step S3 in Figure 4 in that it uses a wavelength-dependent reference obtained by synthesizing the wavelength-dependent references for each optical transmission device. The estimation device 10 receives the OSNR measurement value as input and the reference value OSNR of the available channel. TOTALref (λ T ) and the reference value OSNR of the channel under investigation TOTALref (λ S Read out the OSNR(λ) of the channel under investigation using the following formula. S We estimate ). 【0047】 【0048】 Figure 14 shows the wavelength-dependent reference of the relay section obtained by synthesis, and how the OSNR of the target channel is estimated using the wavelength-dependent reference of the relay section. Measured OSNR (λ) on an empty channel. T )=13.5dB, wavelength λ T Reference value OSNR TOTALref (λ T )=13.95dB, wavelength λ S Reference value OSNR TOTALref (λ S If λ = 13.64 dB, then the estimated OSNR of the channel under investigation is OSNR(λ S) = 13.2 dB. 【0049】 As described above, the estimation device 10 of this embodiment includes a storage unit 13 that holds a wavelength-dependent reference, an input unit 11 that inputs OSNR measurement values ​​measured on an unused channel other than the channel under investigation, and an estimation unit 12 that estimates the OSNR of the channel under investigation from the deviation of the OSNR measurement value on the unused channel from the reference value and the reference value of the channel under investigation. This makes it possible to estimate the OSNR of the channel under investigation without affecting the communication quality of the channel under investigation. 【0050】 According to this embodiment, by measuring a wavelength-dependent reference for each optical transmission device and synthesizing the wavelength-dependent references for each optical transmission device located in the relay section to create a reference value for the channel under investigation, it is possible to create a wavelength-dependent reference for an optical communication relay network of any network configuration in an experimental environment without constructing a network configuration equivalent to that of a commercial environment. 【0051】 The estimation device 10 described above can be a general-purpose computer system, such as the one shown in Figure 15, which includes a central processing unit (CPU) 901, memory 902, storage 903, communication device 904, input device 905, and output device 906. In this computer system, the estimation device 10 is realized when the CPU 901 executes a predetermined program loaded onto the memory 902. This program can be recorded on a computer-readable non-temporary recording medium such as a magnetic disk, optical disk, or semiconductor memory, or it can be distributed via a network. 【0052】 10 Estimation device 11 Input unit 12 Estimation unit 13 Storage unit 100 Optical fiber 110 Optical transmitter 120 Optical receiver 130 Relay node 131 PW light source 132 Monitor 140 Amplifier

Claims

1. An estimation device comprising: a storage unit that holds a reference value of the optical signal-to-noise ratio for each channel in the relay section of an optical signal; an input unit that inputs a measured value of the optical signal-to-noise ratio measured in an unused channel other than the channel under investigation; and an estimation unit that estimates the optical signal-to-noise ratio of the channel under investigation from the deviation of the measured value in the unused channel from the reference value and the reference value of the channel under investigation.

2. Estimation device according to claim 1, comprising measuring the optical signal-to-noise ratio for each channel for each optical transmission device, and creating the reference value by synthesizing the optical signal-to-noise ratios for each optical transmission device arranged in the relay section.

3. An estimation method comprising: obtaining a reference value for the optical signal-to-noise ratio for each channel in the relay section of an optical signal; measuring the optical signal-to-noise ratio in the relay section on an unused channel other than the channel under investigation; and estimating the optical signal-to-noise ratio of the channel under investigation from the deviation of the measured value on the unused channel from the reference value and the reference value of the channel under investigation.

4. An estimation method according to claim 3, comprising measuring the optical signal-to-noise ratio for each channel for each optical transmission device, and creating the reference value by synthesizing the optical signal-to-noise ratios for each optical transmission device arranged in the relay section.

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