Route selection device, route selection method and program

Abstract

To provide a route selection device, a route selection method and a program that can suppress compensation performed on a transmission signal.SOLUTION: A route selection device according to one embodiment comprises: calculation means which, for each of a plurality of signal paths connected to a transmission device, calculates distortion that occurs in a transmission signal output from the transmission device, using information on distortion in the signal path; and selection means which selects one of the plurality of signal paths based upon the distortion that the calculation means calculates.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a route selection device, a route selection method, and a program. [Background technology]

[0002] Techniques are being researched to achieve efficient and high-quality communications.

[0003] For example, Patent Document 1 discloses an all-optical network equipped with optical node devices that perform wavelength conversion using an OAO (optical-analog-optical) wavelength conversion method. In this network, each node monitors the signal quality of the path and performs analog compensation based on the monitoring results, thereby suppressing degradation of signal quality in the path. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2023 / 105669 Summary of the Invention [Problem to be solved by the invention]

[0005] As described in Patent Document 1, signal compensation is performed to suppress deterioration of signal quality. As a signal compensation method, the following two methods can be considered, for example. (i) The wavelength converter performs compensation using digital or analog circuitry. (ii) A signal transmitting device applies to a transmitting signal the inverse characteristics of a wavelength converter on the transmission path of the signal (i.e., performs pre-equalization). However, in method (i), a compensation circuit is required for each wavelength converter, which is thought to increase the cost of the communication system. Furthermore, in method (ii), when the transmission path is changed, the characteristics of the wavelength converters on the transmission path also change as the wavelength converters on the transmission path change. Therefore, it is necessary to change the pre-equalization method executed by the transmitting device, making it difficult to set a unique pre-equalization. Thus, it is expected that signal compensation will cause other problems.

[0006] One of the objectives to be achieved by the embodiments of the present disclosure is to provide a path selection device, a path selection method, and a program that are capable of suppressing compensation performed on a transmission signal. It should be noted that this objective is only one of multiple objectives to be achieved by multiple embodiments disclosed herein. Other objectives or problems and novel features will become apparent from the description of this specification or the accompanying drawings. [Means for solving the problem]

[0007] A path selection device according to one aspect includes: a calculation means for calculating distortion occurring in a transmission signal output from the transmitting device using information on distortion in each of a plurality of signal paths connected to the transmitting device; and a selection means for selecting one signal path from the plurality of signal paths based on the distortion calculated by the calculation means.

[0008] A route selection method according to one aspect includes the steps of: calculating distortion occurring in a transmission signal output from the transmitting device using information on distortion in each of a plurality of signal paths connected to the transmitting device; selecting one signal path from the plurality of signal paths based on the calculated distortion; It is a computer-implemented method.

[0009] In one aspect, the program calculating distortion occurring in a transmission signal output from the transmitting device using information on distortion in each of a plurality of signal paths connected to the transmitting device; selecting one signal path from the plurality of signal paths based on the calculated distortion; This is what causes a computer to execute the above. [Effects of the Invention]

[0010] The present disclosure makes it possible to provide a route selection device, a route selection method, and a program that are capable of suppressing compensation performed on a transmission signal. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a block diagram illustrating an example of a route selection device according to the present disclosure. [Figure 2] 10 is a flowchart illustrating an example of a typical process of the route selection device. [Figure 3] FIG. 1 is a schematic diagram illustrating an example of an optical network system according to the present disclosure. [Figure 4] FIG. 1 is a block diagram illustrating an example of a node according to the present disclosure. [Figure 5] FIG. 1 is a block diagram illustrating an example of a management device according to the present disclosure. [Figure 6] 10 is a flowchart illustrating an example of a representative process of the management device. [Figure 7A] 10 is a flowchart illustrating another example of the process of the management device. [Figure 7B] 10 is a flowchart illustrating another example of the process of the management device. [Figure 8] FIG. 2 is a block diagram illustrating an example of a hardware configuration of an information processing device in which processing of the system or device is executed. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following descriptions and drawings in the embodiments have been omitted or simplified as appropriate for clarity of explanation. Furthermore, in this disclosure, unless otherwise specified, when multiple items are defined as "at least one of multiple items," the definition may mean any one item, or any multiple items including all items.

[0013] Each drawing referenced in the embodiments is merely an example for describing one or more embodiments. Each drawing may not relate to only one particular embodiment, but may also relate to one or more other embodiments. As will be understood by those skilled in the art, various features or steps described with reference to any one drawing can be combined with features or steps shown in one or more other drawings to create, for example, an embodiment not explicitly shown or described. Not all features or steps shown in any one drawing are necessarily required to describe an exemplary embodiment, and some features or steps may be omitted. The order of steps described in any drawing may be changed as appropriate.

[0014] Embodiment 1 [Configuration Description] 1 is a block diagram showing an example of a route selection device according to the present disclosure. The route selection device 10 includes a calculation unit 102 and a selection unit 104. Each unit of the route selection device 10 will be described below.

[0015] The calculation unit 102 calculates the distortion occurring in the transmission signal output from the transmission device using distortion information for each of multiple signal paths connected to the transmission device that transmits the signal. The distortion indicates a change from the original signal waveform, and indicates, for example, deterioration of the frequency characteristics of the signal.

[0016] Here, the signal transmitted by the transmitting device is any digital or analog signal. The signal path connecting the transmitting device and the receiving device has, for example, at least a transmission line and one or more relay devices provided between the transmission lines as components. The relay device has the function of forwarding a signal received from one transmission line to another transmission line. The relay device may be a node having any of the following functions, but the functions of the relay device are not limited to these. A function that amplifies the signal received from one transmission path and transmits it to the other transmission path. A function that converts the wavelength or frequency of a signal received from one transmission path and transmits the converted signal to another transmission path. A function that performs D / A (Digital-to-Analog) or A / D conversion on a signal received from one transmission path and transmits the converted signal to the other transmission path.

[0017] Here, it is assumed that there are multiple signal paths connecting a transmitting device and a receiving device. That is, each signal path has at least some of its components (relay devices or transmission paths) that are different from the other signal paths. In this case, when a transmission signal passes through a signal path, distortion originating from the components of the signal path occurs in the transmission signal. Therefore, when the calculation unit 102 calculates the distortion occurring in the transmission signal for each signal path, it is considered that the distortion occurring in the transmission signal differs for each signal path.

[0018] The calculation unit 102 may calculate the distortion by using, for example, an index indicating the degree of distortion for each component of the signal path as information on the distortion in each signal path. Any index may be used as long as its magnitude indicates the magnitude of the distortion. The distortion information used by the calculation unit 102 is stored in either the path selection device 10 or an external device. The distortion information may be updated as appropriate.

[0019] The selection unit 104 selects one signal path from among the multiple signal paths based on the distortion calculated by the calculation unit 102. As an example, the selection unit 104 may select, from among the multiple signal paths, the signal path for which the distortion calculated by the calculation unit 102 is the smallest. However, the signal path selected by the selection unit 104 is not limited to this. The selected signal path can be used as the path when the transmitting device actually transmits a signal to the receiving device.

[0020] Furthermore, in order to suppress distortion occurring in the signal path selected by the selector 104, the path selection device 10 may cause the transmitting device to execute processing to compensate for all or part of the distortion in the selected signal path. For example, by using information about the distortion in the selected signal path, the path selection device 10 can cause the transmitting device to execute processing to cancel out distortion occurring due to all or part of the components in the signal path.

[0021] [Flow description] 2 is a flowchart showing an example of a typical process of the route selecting device 10. This flowchart explains the process of the route selecting device 10. Note that the details of each process are as described above, and therefore will not be explained as appropriate.

[0022] First, the calculation unit 102 calculates, for each of the plurality of signal paths, the distortion occurring in the transmission signal output from the transmitting device using information on the distortion in the signal path (step S12). The selection unit 104 selects one signal path from the plurality of signal paths based on the distortion calculated by the calculation unit 102 (step S14).

[0023] [Effect description] As described above, the path selection device 10 calculates the distortion occurring in each signal path, and selects one signal path from among multiple signal paths based on the calculation results. This allows the path selection device 10 to select a signal path taking distortion into consideration (for example, to select a signal path with less distortion), thereby reducing the amount of compensation performed on the transmission signal. In other words, when the signal path selected by the path selection device 10 is used for communication, there is no need to perform compensation on the transmission signal, or the degree of compensation performed on the transmission signal can be reduced compared to when one signal path is randomly selected and used.

[0024] Furthermore, the selection unit 104 may select, from among the multiple signal paths, a signal path that minimizes distortion in the transmission signal as a result of the calculation by the calculation unit 102. This allows the path selection device 10 to further suppress compensation performed on the transmission signal.

[0025] The route selection device 10 may be configured as a single computer device, or may be configured as a distributed system having multiple computer devices. In a distributed system, the processing executed by the route selection device 10 can be shared and executed by multiple computer devices. In other words, the calculation unit 102 and the selection unit 104 may be distributed and installed on multiple computer devices.

[0026] Some or all of the components of the route selection device 10 may be provided in a cloud server constructed on a cloud, or in other types of virtualized servers generated using virtualization technology, etc. Functions other than those provided in servers such as cloud servers or virtualized servers are placed at the edge.

[0027] In each of the following embodiments, a specific example of the route selection device 10 described in the first embodiment will be disclosed. However, the specific example of the route selection device 10 described in the first embodiment is not limited to the one shown below. Furthermore, the configurations and processes described below are merely examples, and are not limited to these.

[0028] Embodiment 2 (2A) [Configuration Description] 3 is a schematic diagram showing an example of an optical network system according to the present disclosure. The optical network system P includes nodes A to G and transmission paths N1 to N13 for transmitting optical signals (hereinafter also simply referred to as signals), and a management device S. Here, the transmission path N1 connects nodes A and B, the transmission path N2 connects nodes A and C, and the transmission path N3 connects nodes A and E. The transmission path N4 connects nodes B and C, the transmission path N5 connects nodes B and D, and the transmission path N6 connects nodes B and F. The transmission path N7 connects nodes C and D, the transmission path N8 connects nodes C and E, and the transmission path N9 connects nodes D and E. The transmission path N10 connects nodes D and F, the transmission path N11 connects nodes D and G, the transmission path N12 connects nodes E and G, and the transmission path N13 connects nodes F and G.

[0029] 3 also shows the distortion indexes caused by transmission in each of the transmission paths N1 to N13, and the distortion indexes caused when wavelength conversion of a signal is performed in each of the nodes A to G. Distortion indexes of 3, 4, 9, 2, 9, 9, 3, 6, 5, 2, 4, 4, and 3 are defined for the transmission paths N1 to N13, respectively. The distortion indexes of the transmission paths are determined, for example, by the distance of the transmission path and the communication bandwidth. Furthermore, when wavelength conversion of a signal is performed in each of the nodes A to G, distortion indexes of 2, 3, 3, 3, 1, 2, and 4 are defined, respectively. The distortion indexes of the nodes are determined, for example, by the bandwidth and the frequency characteristics of each node. The larger the distortion index, the greater the degree of distortion caused in the transmission path or node.

[0030] The optical network system P may be a system capable of simultaneously transmitting optical signals of multiple different wavelengths, such as a wavelength division multiplexing (WDM) optical network system. In this optical network system P, the signal paths of the optical signals can be flexibly switched depending on the traffic situation, etc.

[0031] Fig. 4 is a block diagram showing an example of a node. Node H is a general term for nodes A to G in Fig. 3. Node H includes a receiver 202, a transmitter 204, a wavelength converter 206, a wavelength selective switch 208, and a filter 210. Each node may be, for example, a ROADM (Reconfigurable Optical Add / Drop Multiplexer). Each element of node H will be described below.

[0032] The receiving unit 202 is an interface for receiving signals from other nodes, etc., and the transmitting unit 204 is an interface for transmitting signals to other nodes. Node H can transfer received signals to other nodes using the receiving unit 202 and the transmitting unit 204.

[0033] When an event such as a wavelength collision, which will be described later, occurs in the transmission path connected to node H, the wavelength selective switch 208 extracts a wavelength signal that requires wavelength conversion from the signal received by the receiving unit 202 and sends the wavelength signal to the wavelength converting unit 206. The wavelength converting unit 206 performs wavelength conversion on the signal. The wavelength-converted signal is sent to the wavelength selective switch 208. The wavelength selective switch 208 multiplexes the wavelength-converted signal with other wavelength-multiplexed signals, and then causes the multiplexed signal to be transmitted from the transmitting unit 204.

[0034] Node H performs wavelength conversion of signals using an OAO wavelength conversion method. In this method, node H does not have digital or analog circuits for signal distortion compensation. Therefore, when node H performs wavelength conversion, distortion occurs in the signal. The distortion of the signal waveform caused by wavelength conversion depends on the frequency characteristics of the wavelength conversion unit 206 of the node. Therefore, the distortion index determined for wavelength conversion of a node may be a different value depending on the node.

[0035] When multiple nodes H exist in a signal path and multiple wavelength conversions are performed at each node H, distortion accumulates in the signal. Distortion also accumulates in the signal as the signal passes through the transmission path. As a result, signal characteristics deteriorate as the signal is transmitted. Sometimes, communication may become impossible due to the deterioration of characteristics. The management device S disclosed herein can solve this problem.

[0036] The filter unit 210 performs digital filtering on the signal transmitted from the node H. As will be described later, the filter unit 210 can perform pre-equalization on the transmission signal in accordance with the control of the management device S or the like.

[0037] The node H may further have functions such as signal amplification, D / A or A / D conversion, etc., as necessary.

[0038] Fig. 5 is a block diagram showing an example of a management device S. The management device S includes a calculation unit 302, a selection unit 304, a pre-equalization setting unit 306, a network setting unit 308, a transmission / reception unit 310, and a storage unit 312. When transmitting a signal from one of the nodes shown in Fig. 3 to another node, the management device S selects which signal path should be used for transmission. Each element of the management device S will be described below.

[0039] The calculation unit 302 calculates distortion occurring in a transmission signal output from a transmitting device for each of a plurality of signal paths connecting a node that is a transmitting device and a node that is a receiving device. The signal paths that the calculation unit 302 targets for calculation may be all signal paths connecting the transmitting device and the receiving device, or may be some of the signal paths connecting the transmitting device and the receiving device.

[0040] To calculate the distortion, the calculation unit 302 uses information about the distortion of the optical network system P stored in the storage unit 312. The information about the distortion of the optical network system P includes information about the index of distortion occurring in each of the transmission paths N1 to N13 and the index of distortion occurring when wavelength conversion of a signal is performed in each of the nodes A to G, as shown in Fig. 3. The storage unit 312 stores information about this distortion that has been measured in advance.

[0041] In the following example, we will explain the calculation example assuming that node A is the signal transmitting device and node G is the signal receiving device, but similar calculations are possible when the transmitting device and receiving device are other nodes.

[0042] (A) First, assume that there is no wavelength collision of signals in the optical network system P. In this case, nodes on the signal path do not need to perform wavelength conversion. Therefore, the distortion index of each signal path is determined by the distortion index of the transmission line on that signal path. In this example, the following four paths are defined as the signal paths to be calculated: (1) From node A to node G via node E (2) From node A, reach node G via nodes C and D (3) From node A, reach node G via nodes C and E (4) From node A, reach node G via nodes B and F Using the distortion information stored in the storage unit 312, the calculation unit 302 calculates that the distortion indices of (1) to (4) are 13, 11, 14, and 15, respectively.

[0043] (B) Next, assume that a wavelength collision occurs at node N7 in optical network system P. In this case, when using a signal path that passes through node N7, node C must perform wavelength conversion. Among signal paths (1) to (4), distortion due to this wavelength conversion will further occur in path (2). Using the distortion information stored in memory 312, calculation unit 302 calculates that the distortion indices of paths (1) to (4) are 13, 14, 14, and 15, respectively.

[0044] Based on the result of calculation by calculation unit 302, selection unit 304 selects the signal path with the smallest distortion index from among the multiple signal paths that are the subject of calculation. For example, in the case of (A), selection unit 304 selects (2) with the smallest distortion index. On the other hand, in the case of (B), selection unit 304 selects (1) with the smallest distortion index. In this way, selection unit 304 selects the signal path to be used for communication.

[0045] Furthermore, the selector 304 determines whether the distortion index calculated for the signal path selected by the selector 304 is equal to or greater than a predetermined threshold Th1. The threshold Th1 is information that is set in advance and stored in the storage unit 312. This threshold indicates the amount of distortion that is allowable in signal transmission.

[0046] If the distortion index is equal to or greater than the threshold value Th1, that is, if the distortion in the selected signal path is considered to be large, the selector 304 determines that compensation (specifically, pre-equalization) is necessary at node A. On the other hand, if the distortion index is less than the threshold value Th1, that is, if the distortion in the selected signal path is considered to be small, the selector 304 determines that compensation is not necessary at node A.

[0047] When the selection unit 304 determines that compensation is necessary at node A, the pre-equalization setting unit 306 sets node A so that pre-equalization is performed at node A. Specifically, the pre-equalization setting unit 306 sets pre-equalization for the signal transmitted from node A by using a transfer function of the frequency characteristics of node A that is acquired in advance and stored in the storage unit 312.

[0048] For example, assume that (2) is selected as the signal path and wavelength conversion is performed at nodes C and D. Here, the transfer functions of the frequency (ω) characteristics at nodes C and D are respectively G C (ω), G D (ω), the pre-equalization setting unit 306 sets the transfer function of the entire path (2) as G ALL (ω), where G ALL (ω)=G C (ω)·G D (ω) The pre-equalization setting unit 306 uses the transfer function 1 / G ALL Node A generates an instruction to apply (ω) to the signal to be transmitted and outputs it to node A via transmitter / receiver 310. Upon receiving the instruction via receiver 202, node A controls filter unit 210 to apply the instructed transfer function to the transmitted signal. As a result, even if wavelength conversion is performed at nodes C and D in (2), the influence of distortion due to wavelength conversion is suppressed in the signal when it arrives at signal node G.

[0049] The network setting unit 308 sets up the optical network system P so that communication is carried out via the signal path selected by the selection unit 304 .

[0050] The transceiver 310 transmits and receives data to and from each node in the optical network system P. For example, the transceiver 310 transmits and receives data to and from each node, such as the transfer function determined by the pre-equalization setting unit 306 and the settings of the optical network system P set by the network setting unit 308. The transceiver 310 may also receive information about distortion in the optical network system P from another device.

[0051] The storage unit 312 stores information about distortion in the optical network system P, the distortion calculation method of the calculation unit 302, the transfer function of the frequency characteristics of each node, and the like.

[0052] [Flow description] 6 is a flowchart showing an example of a representative process of the management device S. This flowchart explains the process of the management device S. Note that the details of each process are as described above, and therefore will not be explained further.

[0053] First, the calculation unit 302 calculates the distortion index occurring in the transmission signal output from the transmission device for each of the plurality of signal paths connecting the transmission device and the reception device (step S22). Then, the selection unit 304 selects the signal path with the smallest distortion index based on the result of the calculation by the calculation unit 302 (step S24). The selection unit 304 determines whether the identified distortion index is equal to or greater than a threshold value Th1 (step S26).

[0054] If the distortion index is less than the threshold value Th1 (No in step S26), the selector 304 determines that pre-equalization is not required in the transmitting device. In this case, pre-equalization is not set in the transmitting device. The network setting unit 308 sets the optical network system P so that communication is performed via the signal path selected in step S24 (step S28).

[0055] On the other hand, if the distortion index is equal to or greater than the threshold Th1 (Yes in step S26), the selection unit 304 determines that pre-equalization in the transmitting device is necessary. In this case, the pre-equalization setting unit 306 sets pre-equalization in the transmitting device so that pre-equalization is performed in the transmitting device (step S30). Thereafter, the network setting unit 308 executes the process of step S28.

[0056] Note that the processes of steps S26 and S30 and the process of step S28 may be executed in any order, or both processes may be executed in parallel.

[0057] As a modified example, the management device S may not execute the processes of steps S26 and S30. In other words, the management device S may not set pre-equalization for the signal path selected by the selection unit 304. However, by executing the processes of steps S26 and S30, pre-equalization is performed as needed, thereby improving the quality of the transmission signal.

[0058] Furthermore, the management device S may not execute the process of step S26 and may execute the setting of pre-equalization shown in step S30 regardless of the value of the distortion index of the selected signal path. However, by executing the process of step S26 and setting pre-equalization when the distortion index is large, the management device S can prevent the execution of compensation processing when it is not necessary.

[0059] [Effect description] As described above, the management device S selects, from among multiple signal paths, a signal path that minimizes distortion in the transmission signal. This allows the management device S to suppress compensation for the transmission signal. Furthermore, by selecting a signal path, the management device S can uniquely set pre-equalization for the transmission device. Furthermore, since there is no need to provide a compensation circuit in each node of the optical network system P, the cost of building the system can be reduced.

[0060] Furthermore, the pre-equalization setting unit 306 causes the transmitting device to execute processing to compensate for distortion in the selected signal path. This allows the management device S to improve the quality of the transmitted signal. In particular, the pre-equalization setting unit 306 causes the transmitting device to execute pre-equalization, thereby allowing the transmitting device to execute compensation in a simple manner. However, the distortion compensation processing that can be executed by the transmitting device is not limited to pre-equalization.

[0061] Furthermore, the pre-equalization setting unit 306 may cause the transmitting device to perform a process of compensating for distortion when the distortion index in the selected signal path is equal to or greater than a predetermined threshold Th1. This allows the management device S to improve the quality of the transmitted signal when the need for compensation is high, while suppressing the execution of compensation when the need for compensation is low.

[0062] Furthermore, the calculation unit 302 may calculate the distortion occurring in the transmission signal for each of the plurality of signal paths based on the distortion due to the transmission path and the distortion due to wavelength conversion, thereby enabling the management device S to accurately calculate the distortion of the signal path.

[0063] In the above example, the calculation unit 302 calculates the distortion index occurring in the transmission signal by simply adding up the distortion indexes of each component element on the signal path. However, the calculation unit 302 may arbitrarily weight the distortion indexes of each component element on the signal path depending on traffic conditions, etc. The calculation unit 302 can calculate the distortion index occurring in the transmission signal on the signal path by adding up the weighted distortion indexes.

[0064] (2B) Below, we will explain examples of variations of the processing of the management device S shown in (2A). Below, we will omit explanations of points that have already been explained in (2A) as appropriate, and will focus on the processing that is unique to (2B).

[0065] In (2A), the management device S selected the signal path with the smallest distortion index calculated in step S22 of Fig. 6 as the path to be used for communication. However, the path selected by the management device S as the path to be used for communication is not limited to the signal path with the smallest distortion index calculated in step S22 of Fig. 6.

[0066] Specifically, the calculation unit 302 calculates the distortion index for multiple signal paths, and when it identifies the one with the smallest distortion index, it determines whether the identified distortion index is equal to or greater than a predetermined threshold value Th2. This threshold value Th2 may be the same as or different from the threshold value Th1.

[0067] If the identified distortion index is less than a predetermined threshold Th2, the selector 304 selects the signal path associated with the identified distortion index as the signal path to be used for communication.

[0068] If the identified distortion index is equal to or greater than a predetermined threshold Th2, the calculation unit 302 further performs the following calculation. For each of the multiple signal paths for which the distortion index is calculated, the calculation unit 302 calculates the distortion index of the signal path when pre-equalization is performed by the transmitting device. Then, the selection unit 304 selects the signal path for which the distortion index is smallest when pre-equalization is performed as the path to be used for signal transmission.

[0069] Note that when pre-equalization is performed by the transmitting device, the distortion indexes of the signal paths to be calculated may be all of the signal paths that are initially subjected to the distortion index calculation, or may be a portion of the signal paths among all of the signal paths that are initially subjected to the distortion index calculation. The portion of the signal paths may be, for example, signal paths whose calculated distortion indexes are equal to or less than a predetermined threshold Th3.

[0070] After the selection unit 304 selects a signal path to be used for communication in this manner, whether or not to perform pre-equalization may be determined depending on the magnitude of the distortion index of the selected signal path. Alternatively, pre-equalization may or may not be performed regardless of the distortion index of the selected signal path. This is explained in (2A).

[0071] The following describes the situation (B) in (2A) as an example. When a signal wavelength collision occurs at node N7 in optical network system P, the calculation unit 302 calculates the distortion indexes (1) to (4) to be 13, 14, 14, and 15, respectively. Here, the calculation unit 302 determines whether the smallest distortion index, 13, is equal to or greater than threshold value Th2.

[0072] If the threshold Th2 exceeds 13, the selector 304 selects (1), which corresponds to the distortion index 13, as the signal path to be used for communication. On the other hand, if the threshold Th2 is equal to or less than 13, the calculator 302 uses distortion information of the optical network system P to calculate the distortion index of the signal path for each of (1) to (4) when pre-equalization is performed by node A. In this recalculation, it is assumed that pre-equalization will eliminate all distortion caused by wavelength conversion performed at node C. As a result of the recalculation, the calculator 302 calculates the distortion indexes of (1) to (4) to be 13, 11, 14, and 15, respectively.

[0073] In the above recalculation, the distortion index subtracted by pre-equalization from the distortion index indicated by the initial calculation result is not limited to the same value as the distortion index in the wavelength conversion of the node, but may be a part of the value of the distortion index in the wavelength conversion of the node. Furthermore, even if distortion due to wavelength conversion occurs in a signal path other than (2), the calculation unit 302 can recalculate the distortion index of that signal path in the same manner as (2).

[0074] The selection unit 304 selects (2), which corresponds to the distortion index 11 that is the smallest as a result of the recalculation, as the signal path to be used for communication. Then, the network setting unit 308 sets up the optical network system P so that communication is performed via the signal path selected by the selection unit 304.

[0075] [Flow description] 7A and 7B are flowcharts showing an example of a representative process of the management device S. This flowchart explains the process of the management device S. Note that the details of each process are as described above, and therefore will not be explained as appropriate.

[0076] First, the calculation unit 302 calculates the distortion index occurring in the transmission signal (step S32). This is the same as step S22 in Fig. 6. Then, the calculation unit 302 identifies the smallest distortion index among the distortion indexes calculated in step S32 (step S34). The calculation unit 302 determines whether the identified distortion index is equal to or greater than a threshold value Th2 (step S36).

[0077] If the identified distortion index is less than the threshold Th2 (No in step S36), the selector 304 selects the signal path associated with the distortion index identified in step S34 as the signal path to be used for communication (step S38). The network setting unit 308 sets the optical network system P so that communication is performed via the signal path selected in step S38 (step S40).

[0078] If the identified distortion index is equal to or greater than threshold value Th2 (Yes in step S36), calculation unit 302 calculates the distortion index of each of the signal paths that were the subject of calculation in step S32 when pre-equalization is performed by the transmitting device (step S42). Then, selection unit 304 selects the signal path that has the smallest distortion index when pre-equalization is performed as the path to be used for signal transmission (step S44). Network setting unit 308 executes the process described in step S40.

[0079] After performing at least one of step S38 and step S44, the management device S may perform step S26 and subsequent steps shown in Fig. 6. In this case, the threshold value Th2 may be set to a value greater than the threshold value Th1.

[0080] [Effect description] As described above, the selector 304 selects a signal path with the smallest distortion among the distortions that occur when the transmitting device performs processing to compensate for distortion in the signal path (for example, pre-equalization). This enables the management device S to select a signal path with less distortion, thereby improving signal quality.

[0081] Furthermore, when the smallest distortion index among the distortions of the signal paths that occur when distortion compensation processing is not performed is equal to or greater than threshold value Th2, calculation unit 302 may calculate, for each signal path, the distortion of the signal path that occurs when distortion compensation processing is performed. Selector 304 selects a signal path based on the calculation result. This allows management device S to improve the quality of the transmitted signal when compensation processing is highly necessary, while suppressing the execution of compensation processing when compensation processing is low.

[0082] Like the route selection device 10, the management device S may be configured as a single computer device, or may be configured as a distributed system having a plurality of computer devices.

[0083] In the above-described embodiment, the present disclosure has been described as a hardware configuration, but the present disclosure is not limited to this. The present disclosure can also be realized by causing a processor in a computer to execute a computer program to perform the processing of the devices constituting the route selection device 10 or management device S described in the above-described embodiment.

[0084] 8 is a block diagram showing an example of the hardware configuration of an information processing device (i.e., a computer) that executes the processing of the system or device described in each embodiment. Referring to FIG. 8, an information processing device 90 includes a signal processing circuit 91, a processor 92, and a memory 93.

[0085] The signal processing circuit 91 is a circuit for processing signals in accordance with the control of the processor 92. The signal processing circuit 91 may include a communication circuit for receiving signals from a transmitting device.

[0086] The processor 92 is connected to the memory 93, and performs the processing of the system described in the above embodiment by reading and executing a computer program from the memory 93. As an example of the processor 92, one of a CPU (Central Processing Unit), an MPU (Micro Processing Unit), an FPGA (Field-Programmable Gate Array), a DSP (Digital Signal Processor), and an ASIC (Application Specific Integrated Circuit) may be used, or a plurality of these may be used in parallel.

[0087] The memory 93 is configured with a volatile memory, a nonvolatile memory, or a combination thereof. The memory 93 is not limited to one, and multiple memories may be provided. The volatile memory may be, for example, a RAM (Random Access Memory) such as a DRAM (Dynamic Random Access Memory) or an SRAM (Static Random Access Memory). The nonvolatile memory may be, for example, a ROM (Read Only Memory) such as a PROM (Programmable Random Only Memory) or an EPROM (Erasable Programmable Read Only Memory), a flash memory, or an SSD (Solid State Drive).

[0088] The memory 93 is used to store one or more instructions. Here, the one or more instructions are stored as programs in the memory 93. The processor 92 can perform the processes described in the above embodiments by reading and executing these programs from the memory 93.

[0089] The memory 93 may include memory built into the processor 92 in addition to memory provided outside the processor 92. The memory 93 may also include storage located away from the processors constituting the processor 92. In this case, the processor 92 can access the memory 93 via an I / O (Input / Output) interface.

[0090] As described above, one or more processors included in each device in the above-described embodiments execute one or more programs including instructions for causing a computer to execute the algorithms described using the drawings. Execution of the programs enables the information processing described in each embodiment to be realized.

[0091] The program includes instructions or software code that, when loaded into a computer, causes the computer to perform one or more functions described in the embodiments. The program may be stored in a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable media or tangible storage media include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disk (DVD), Blu-ray disc or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices. The program may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable media or communication media include electrical, optical, acoustic, or other forms of propagated signals. The transitory computer-readable medium or communication medium may provide the program to the computer via a wired communication path, such as electrical wires and optical fibers, or via a wireless communication path.

[0092] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes. (Appendix 1) a calculation means for calculating distortion occurring in a transmission signal output from the transmitting device using information on distortion in each of a plurality of signal paths connected to the transmitting device; a selection means for selecting one signal path from the plurality of signal paths based on the distortion calculated by the calculation means, Route selection device. (Appendix 2) the selection means selects a signal path from the plurality of signal paths that minimizes the distortion occurring in the transmission signal. 2. The route selection device of claim 1. (Appendix 3) a control unit that causes the transmitting device to execute a process of compensating for the distortion of the signal path selected by the selection unit, 3. The route selection device according to claim 2. (Appendix 4) the control means causes the transmitting device to perform the process when the index indicating the distortion in the signal path selected by the selection means is equal to or greater than a predetermined threshold. 4. The route selection device according to claim 3. (Appendix 5) the control means causes the transmitting device to perform the processing by imparting to the transmitting signal an inverse characteristic of a wavelength converter on a signal path that minimizes the distortion; 5. A route selection device according to claim 3 or 4. (Appendix 6) the calculation means calculates, for each of the plurality of signal paths, distortion of the signal path that occurs when the transmission device executes a process to compensate for the distortion of the signal path; the selection means selects a signal path that minimizes the distortion when the processing is performed. 2. The route selection device of claim 1. (Appendix 7) the calculation means calculates distortion of the signal path that occurs when the processing is performed for each of the plurality of signal paths when an index indicating the distortion of the signal path that causes the smallest distortion in the transmission signal is equal to or greater than a predetermined threshold value; the selection means selects a signal path that minimizes the distortion when the processing is performed. 7. The route selection device according to claim 6. (Appendix 8) the calculation means calculates the distortion occurring in the transmission signal for each of the plurality of signal paths based on the distortion due to the transmission path and the distortion due to wavelength conversion. A route selection device according to any one of appendixes 1 to 7. (Appendix 9) calculating distortion occurring in a transmission signal output from the transmitting device using information on distortion in each of a plurality of signal paths connected to the transmitting device; selecting one signal path from the plurality of signal paths based on the calculated distortion; A computer-implemented route selection method. (Appendix 10) calculating distortion occurring in a transmission signal output from the transmitting device using information on distortion in each of a plurality of signal paths connected to the transmitting device; selecting one signal path from the plurality of signal paths based on the calculated distortion; A program that makes a computer do something.

[0093] Some or all of the elements (e.g., configurations and functions) described in Supplementary Notes 2 to 8 that are dependent on Supplementary Note 1 may also be dependent on Supplementary Notes 9 and 10 in the same dependency relationship as Supplementary Notes 2 to 8. Some or all of the elements described in any Supplementary Note may be applied to various hardware, software, recording means for recording software, systems, and methods.

[0094] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate. [Explanation of symbols]

[0095] 10 Route selection device 102 calculation unit 104 selection unit P Optical Network System H-node 202 receiving section 204 transmitting section 206 wavelength conversion section 208 Wavelength selective switch 210 Filter section S management device 302 calculation unit 304 selection unit 306 pre-equalization setting unit 308 Network setting unit 310 Transmitting / receiving unit 312 Storage section

Claims

1. a calculation means for calculating distortion occurring in a transmission signal output from the transmitting device using information on distortion in each of a plurality of signal paths connected to the transmitting device; a selection means for selecting one signal path from the plurality of signal paths based on the distortion calculated by the calculation means, Route selection device.

2. the selection means selects a signal path from the plurality of signal paths that minimizes the distortion occurring in the transmission signal.

2. The route selection device according to claim 1.

3. a control unit that causes the transmitting device to execute a process of compensating for the distortion of the signal path selected by the selection unit, 3. The route selection device according to claim 2.

4. the control means causes the transmitting device to perform the process when the index indicating the distortion in the signal path selected by the selection means is equal to or greater than a predetermined threshold.

4. The route selection device according to claim 3.

5. the control means causes the transmitting device to perform the processing by imparting to the transmitting signal an inverse characteristic of a wavelength converter on a signal path that minimizes the distortion; 5. The route selection device according to claim 3 or 4.

6. the calculation means calculates, for each of the plurality of signal paths, distortion of the signal path that occurs when the transmission device executes a process to compensate for the distortion of the signal path; the selection means selects a signal path that minimizes the distortion when the processing is performed.

2. The route selection device according to claim 1.

7. the calculation means calculates distortion of the signal path that occurs when the processing is performed for each of the plurality of signal paths when an index indicating the distortion of the signal path that causes the smallest distortion in the transmission signal is equal to or greater than a predetermined threshold value; the selection means selects a signal path that minimizes the distortion when the processing is performed.

7. The route selection device according to claim 6.

8. the calculation means calculates the distortion occurring in the transmission signal for each of the plurality of signal paths based on the distortion due to the transmission path and the distortion due to wavelength conversion.

8. A route selection device according to any one of claims 1 to 4 and 6 to 7.

9. calculating distortion occurring in a transmission signal output from the transmitting device using information on distortion in each of a plurality of signal paths connected to the transmitting device; selecting one signal path from the plurality of signal paths based on the calculated distortion; A computer-implemented route selection method.

10. calculating distortion occurring in a transmission signal output from the transmitting device using information on distortion in each of a plurality of signal paths connected to the transmitting device; selecting one signal path from the plurality of signal paths based on the calculated distortion; A program that makes a computer do something.

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