Communication systems, communication devices, methods, and programs

Abstract

To provide a communication system, a communication device, a method, and a program capable of suppressing the influence of disturbance on a transmission signal input to each of a communication devices in a communication system in which the plurality of communication devices are connected in series.SOLUTION: A communication system includes a first transponder device 10A connected in series via an optical communication cable, and at least one second transponder device. The second transponder device 10B calculates an index value indicating the quality of the transmission signal received from the transponder device arranged adjacently on the upstream side. When the transponder device located upstream of the own device receives recovery information indicating that the transponder device has recovered from the input signal failure, the second transponder device 10B determines whether the calculated index value is within a predetermined range, and when it is determined that the index value is not within the default range, the second transponder device executes a reset process on the optical module that the device has and receives the transmission signal.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a communication system in which a plurality of communication devices are connected in series, a communication device, a method, and a program. [Background Art]

[0002] Conventionally, various techniques have been proposed for recovering from a failure when a failure occurs in a communication system in which a plurality of communication devices are connected in series.

[0003] As an example of such a technique, the optical multiplexer / demultiplexer disclosed in Patent Document 1 monitors optical signals from a working line and a protection line respectively to detect whether a failure has occurred, and determines an available valid line among the working line and the protection line based on the detection result of whether a failure has occurred. Then, the optical multiplexer / demultiplexer demultiplexes an optical signal of a specific wavelength from the optical signal obtained from the valid line and supplies it to a client. Then, the optical multiplexer / demultiplexer outputs the specific-wavelength optical signal output from the client to the line determined to have no failure. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Laid-Open No. 2003-258730 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] However, since the technique disclosed in Patent Document 1 outputs a specific-wavelength optical signal, which is a transmission signal, to a line where no failure has occurred, it cannot suppress the influence of a failure of the transmission signal input to each communication device in a communication system in which a plurality of communication devices are connected in series.

[0006] In view of the above-mentioned problems, the purpose of this disclosure is to provide a communication system, communication device, method, and program that can suppress the effects of failures in transmission signals input to each communication device in a communication system in which multiple communication devices are connected in series. [Means for solving the problem]

[0007] A communication system in which a plurality of communication devices according to one exemplary embodiment are connected in series via an optical communication cable is: The first communication device and The system includes at least one second communication device located downstream of the first communication device, The first communication device is A first optical module that processes transmission signals received from a communication device located adjacent to the upstream side of its own device, A fault detection unit that detects faults in the input signal to the first communication device, When the fault detection unit detects a fault in the input signal, the first optical module control unit causes the first optical module to perform a reset process to receive a new input signal, The system includes a transmitting unit that, when the first communication device recovers from an input signal failure by performing a reset process on the first optical module, transmits recovery information to the second communication device indicating that the first communication device has recovered from the failure. The second communication device is A second optical module that processes transmission signals received from a communication device located adjacent to the upstream side of its own device, An index value calculation unit that performs an index value calculation process to calculate an index value indicating the quality of a transmission signal received from a communication device located adjacent to the upstream side of the device, An index value determination unit, upon receiving recovery information, executes an index value determination process to determine whether the index value calculated by the index value calculation unit is within a predetermined range, The system includes a second optical module control unit that, if the index value determination unit determines that the index value is not within a predetermined range, causes the second optical module to perform a reset process that causes it to receive a new transmission signal.

[0008] A communication device connected in series with another communication device via an optical communication cable according to an exemplary embodiment is: An optical module that processes transmission signals received from a communication device located adjacent to the upstream side of its own device, An index value calculation unit calculates an index value indicating the quality of the transmission signal received from a communication device located adjacent to the upstream side, When a communication device located upstream of the device receives recovery information indicating that it has recovered from an input signal failure, the index value determination unit determines whether the index value calculated by the index value calculation unit is within a predetermined range. The system includes an optical module control unit that, if the index value determination unit determines that the index value is outside a predetermined range, causes the optical module to perform a reset process that allows it to receive a new transmission signal.

[0009] A method performed by a communication device connected in series with another communication device via an optical communication cable according to an exemplary embodiment is: An index value indicating the quality of the transmission signal received from a communication device located adjacent to the upstream side is calculated. When a communication device located upstream of this device receives recovery information indicating that it has recovered from an input signal failure, it determines whether the calculated index value is within a predetermined range. If the calculated index value is determined to be outside the predetermined range, the device will instruct its optical module, which processes transmission signals, to perform a reset process that causes it to receive a new transmission signal.

[0010] A program according to one exemplary embodiment applies to a communication device connected in series with another communication device via an optical communication cable. The steps include: calculating an index value indicating the quality of the transmission signal received from a communication device located adjacent to the upstream side of the device; When a communication device located upstream of the device receives recovery information indicating that it has recovered from an input signal failure, the device determines whether the calculated index value is within a predetermined range. if it is determined that the calculated index value is not within a predetermined range, causing the optical module that processes a transmission signal included in the own device to execute a reset process that causes the optical module to receive a new transmission signal. [Effects of the Invention]

[0011] According to the present disclosure, a communication system, a communication device, a method, and a program capable of suppressing the influence of a failure of a transmission signal input to each communication device in a communication system in which a plurality of communication devices are connected in series can be provided. [Brief Description of the Drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing an example of a communication system according to an exemplary embodiment. [Figure 2] FIG. 2 is a diagram showing a hardware configuration of a first transponder device according to an exemplary embodiment. [Figure 3] FIG. 3 is a block diagram showing functions of a first transponder device according to an exemplary embodiment. [Figure 4] FIG. 4 is a diagram showing a hardware configuration of a second transponder device according to an exemplary embodiment. [Figure 5] FIG. 5 is a diagram showing an example of a program executed by an arithmetic device according to an exemplary embodiment. [Figure 6] FIG. 6 is a sequence diagram showing an example of processing executed in a communication system according to an exemplary embodiment. [Figure 7] FIG. 7 is a flowchart showing an example of processing executed by a second transponder device according to an exemplary embodiment. [Figure 8] FIG. 8 is a diagram showing main components included in a first transponder device and a second transponder device according to an exemplary embodiment. [Mode for Carrying Out the Invention]

[0013] The following describes exemplary embodiments with reference to the drawings. Figure 1 is a diagram showing an example of a communication system 1 according to an exemplary embodiment. The communication system 1 includes a plurality of communication devices connected in series via an optical communication cable 30. Specific examples of communication devices include transponder devices. In this embodiment, a transponder device is used as the communication device.

[0014] In the example shown in Figure 1, communication system 1 includes transponder device 10A, transponder device 10B, transponder device 20A, and transponder device 20B. Transponder devices 10A, 10B, 20A, and 20B correspond to communication devices. Transponder device 10A and transponder device 10B form a pair. Similarly, transponder device 20A and transponder device 20B form a pair. In the example shown in Figure 1, communication system 1 includes two pairs of transponder devices, but communication system 1 may include three or more pairs of transponder devices.

[0015] Transponder devices 10A and 20A detect whether or not a fault has occurred in the input signal to their own devices. When transponder devices 10A and 20A detect a fault in the input signal, they reset the optical module they have installed in their devices to recover from the fault. Then, when transponder devices 10A and 20A recover from the fault, they transmit recovery information to the transponder devices located adjacent to them downstream, indicating that they have recovered from the fault. On the other hand, when transponder devices 10A and 20A receive recovery information from another transponder device located upstream of them, they transmit that recovery information to the transponder devices 20A and 20B located adjacent to them downstream.

[0016] When transponder devices 10B and 20B receive recovery information from another transponder device located upstream of them, they determine the quality of the transmission signal received from the transponder device located adjacent to them upstream. If the quality of the transmission signal does not meet a certain standard, transponder devices 10B and 20B receive a new transmission signal from the transponder device located adjacent to them upstream.

[0017] Figure 2 shows the hardware configuration of a transponder device 10A according to an exemplary embodiment. The transponder device 20A has the same configuration as the transponder device 10A.

[0018] The transponder device 10A comprises an O(Optical) / E(Electrical) converter 11A, a framer IC (Integrated Circuit) 12A, and a processing unit 13A included in the client block, and a processing unit 14A and an optical module 15A included in the line block. The client block of the transponder device 10A is a functional block that maps the client-side interface, which is the connection point with the communication device used by the user of the communication system 1. The line block of the transponder device 10A is a functional block that modulates the transmission signal and transmits it to the transponder device 10B located adjacent to it downstream.

[0019] The O / E converter 11A converts optical signals into electrical signals. The framer IC 12A performs mapping processing, overhead (OH) processing, and forward error correction (FEC) processing related to the input signal to the transponder device 10A.

[0020] The arithmetic unit 13A detects faults in the input signal to the transponder device 10A and notifies the arithmetic unit 14A of the fault in the input signal. A specific example of the arithmetic unit 13A is an FPGA (Field-Programmable Gate Array). In addition, various processors such as a CPU (Central Processing Unit) or MPU (Micro Processing Unit), or integrated circuits such as an ASIC (Application Specific Integrated Circuit) may be used as the arithmetic unit 13A.

[0021] When the arithmetic unit 14A receives notification from the arithmetic unit 13A that an input signal failure has occurred, it instructs the optical module 15A to perform a reset process to receive a new transmission signal. After the reset process by the optical module 15A is completed, the arithmetic unit 14A transmits recovery information to the transponder unit 10B, which is located adjacent to the downstream side of the transponder unit 10A, via the optical module 15A, indicating that the transponder unit 10A has recovered from the input signal failure. An example of the arithmetic unit 14A is an FPGA. In addition, various processors such as CPUs and MPUs, and integrated circuits such as ASICs may be used as the arithmetic unit 14A.

[0022] The optical module 15A processes the transmission signal received from the communication device located upstream of the transponder device 10A. Specifically, the optical module 15A modulates the received transmission signal and transmits it to the transponder device 10B. The optical module 15A also performs a reset process based on instructions from the arithmetic unit 14A and receives a new transmission signal. The optical module 15A may also perform other processes such as over-clocking.

[0023] Figure 3 is a block diagram showing the functions of a transponder device 10A according to an exemplary embodiment. The transponder device 10A includes a fault detection unit 101, an optical module control unit 102, and a transmission unit 103. In this embodiment, the fault detection unit 101 can be implemented by a computing device 13A. The optical module control unit 102 and the transmission unit 103 can be implemented by a computing device 14A. In other embodiments, a single computing device may implement the fault detection unit 101, the optical module control unit 102, and the transmission unit 103.

[0024] The fault detection unit 101 is a means for detecting faults in the input signals to the transponder device 10A. Specifically, the fault detection unit 101 monitors the power level of the optical input to the transponder device 10A and can detect a decrease in the power level of the optical input as a fault in the input signal. In addition, the fault detection unit 101 performs synchronization detection to determine whether the frames of multiple input signals to the transponder device 10A are synchronized, and if these input signal frames are asynchronous, it can detect this event as a fault in the input signal.

[0025] The optical module control unit 102 is a means for controlling the optical module 15A. When the fault detection unit 101 detects a fault in the input signal, the optical module control unit 102 causes the optical module 15A to perform a reset process to receive a new input signal. The reset process may include a process in which the optical module 15A discards transmission signals that it has already received. Through the reset process, transmission signals related to the fault, such as asynchronously received transmission signals or transmission signals with reduced input levels, are discarded by the optical module 15A.

[0026] The transmitting unit 103 is a means for transmitting recovery information to the transponder device 10B, which is located adjacent to the downstream side of the transponder device 10A, indicating that the transponder device 10A has recovered from an input signal failure when the optical module 15A performs a reset process.

[0027] Figure 4 shows the hardware configuration of a transponder device 10B according to an exemplary embodiment. The transponder device 20B has the same configuration as the transponder device 10B.

[0028] The transponder device 10B comprises an E / O converter 11B, a framer IC 12B, and a computing unit 13B included in the client block, and a computing unit 14B, an optical module 15B, and a storage device 16B included in the line block. The client block of the transponder device 10B is a functional block that performs demapping of the client-side interface.

[0029] The optical module 15B is a device that processes transmission signals received from transponder device 10A, which is located adjacent to the upstream side of transponder device 10B. Specifically, the optical module 15B performs a reset process based on instructions from the computing unit 14B and receives a new transmission signal from transponder device 10A. The optical module 15B also receives the transmission signal transmitted by transponder device 10A and performs processing such as OH processing and FEC processing related to the said transmission signal.

[0030] The storage device 16B is a storage device that stores data processed by the arithmetic unit 14B. The storage device 16B stores, for example, information for determining an index value indicating the quality of a transmission signal received by the transponder device 10B from a transponder device 10A located adjacent to the upstream side of the transponder device 10B, and information used to determine the index value.

[0031] The arithmetic unit 14B is a device that executes the program 110 according to this disclosure. When the arithmetic unit 14B receives notification from the transponder device 10A that an input signal failure has occurred, it causes the optical module 15B to perform a reset process. Then, when the reset process by the optical module 15B is completed, the arithmetic unit 14B transmits recovery information that the transponder device 10A has recovered from the input signal failure to the transponder device 20A, which is located adjacent to the downstream side of the transponder device 10B, via each device in the client block. The arithmetic unit 14B may also perform processing such as OH processing related to the transmission signal received from the transponder device 10A. An example of the arithmetic unit 14B is an FPGA. In addition, various processors such as CPUs and MPUs, and integrated circuits such as ASICs may be used as the arithmetic unit 14B. The arithmetic unit is equivalent to a computer.

[0032] Figure 5 shows an example of a program 110 executed by a computing device 14B according to an exemplary embodiment. The program 110 includes a reception determination unit 111, an optical module control unit 112, an index value calculation unit 113, an index value determination unit 114, an optical output determination unit 115, and a transmission unit 116.

[0033] The reception determination unit 111 is a program that determines whether or not it has received recovery information indicating that another transponder device located upstream of the transponder device 10B has recovered from a malfunction.

[0034] The optical module control unit 112 is a program that controls the optical module 15B. In predetermined cases, the optical module control unit 112 causes the optical module 15B to perform a reset process that causes it to receive a new transmission signal from the transponder device 10A located adjacent to it on the upstream side. The reset process may include a process in which the optical module 15B discards transmission signals that it has already received. Through the reset process, transmission signals related to faults, such as asynchronously received transmission signals or transmission signals with reduced input levels, are discarded by the optical module 15B.

[0035] The index value calculation unit 113 is a program that calculates an index value indicating the quality of the transmission signal received from transponder device 10A, which is located adjacent to the upstream side of transponder device 10B. In this embodiment, the index value calculation unit 113 can calculate the Q value (Quality factor) [dB] as an index value from the bit error rate (BER) of the transmission signal received from transponder device 10A. When the bit error rate of the transmission signal is low, that is, when the quality of the transmission signal is high, the Q value becomes large. On the other hand, when the bit error rate of the transmission signal is high, that is, when the quality of the transmission signal is low, the Q value becomes small.

[0036] The index value determination unit 114 is a program that determines whether the index value calculated by the index value calculation unit 113 is within a predetermined range. In this embodiment, the index value determination unit 114 determines whether the Q value, which indicates the quality of the transmission signal received from the transponder device 10A, is within a predetermined range. The threshold that defines the predetermined range can be set based on the Q value of the transmission signal when the quality is not degraded. For example, if the Q value of the transmission signal when the quality is not degraded is X (dB), the upper limit of the predetermined range can be set to +X (dB), and the lower limit of the predetermined range can be set to -X (dB). Here, X is an arbitrary number. X can be determined according to the environmental conditions, which are the conditions of the environment in which the optical communication cable 30 is installed. In other words, the predetermined range is determined individually according to the environmental conditions of each optical communication cable 30 connected to the transponder device that determines the Q value of the transmission signal. The communication system 1 is used to realize ultra-long-distance optical communication and can be installed on land or underwater.

[0037] When the optical communication cable 30 is installed on the seabed, the environmental conditions include various factors such as the seabed topography, water depth, ocean current speed, ocean current fluctuations, water pressure, and seawater temperature. When the optical communication cable 30 is installed on land, the environmental conditions include various factors such as the topography of the location where the optical communication cable 30 is installed, wind speed, precipitation, and air temperature. The default range of the index value corresponding to each environmental condition is connected to a transponder device that determines the index value and can be determined based on actual fluctuations in the index value of the optical communication cable 30 actually installed on the seabed or on land. More specifically, the default range can be a range where the upper and lower limits are the maximum and minimum values ​​of the index value of the transmission signal received via the optical communication cable 30 installed in the actual installation environment such as the seabed or on land, when no problems occur with the transmission signal. The computing unit 14B can update the range of the index value used by the index value determination unit 114 based on information indicating the range of new index values ​​received from an external device. In this case, the information used for the update can be collected as a log by the transponder device in operation.

[0038] In this embodiment, a default range with an upper limit is set to determine the Q value, which indicates the quality of the transmitted signal. The default range can be theoretically determined according to the scale of the transmission system, the transmission rate, the modulation method, etc., but in reality, it is possible that a Q value exceeding the theoretically determined upper limit may be detected. In this embodiment, an upper limit is used in determining the Q value in order to detect such Q values ​​that exceed the theoretical upper limit as abnormal values. This makes it possible to detect abnormal values ​​that exceed the theoretical upper limit.

[0039] The optical output determination unit 115 is a program that determines the optical output status of the client block. The optical output status of the client block can be either ON (where optical output is emitted from transponder device 10B to the transponder device downstream of transponder device 10B) or OFF (where optical output is not emitted from transponder device 10B to the transponder device downstream of transponder device 10B). Therefore, the optical output determination unit 115 determines whether or not optical output is emitted from transponder device 10B to the transponder device downstream of transponder device 10B.

[0040] The transmitting unit 116 is a program that, when the transponder device 10B receives recovery information, transmits the recovery information to the transponder device 20A, which is located adjacent to the downstream side of the transponder device 10B.

[0041] When the arithmetic unit 13B receives recovery information from the arithmetic unit 14B, it instructs the framer IC 12B to transmit the recovery information to the transponder device 20A. The arithmetic unit 13B also performs processing such as over-clocking (OH) on the input signal to the transponder device 10B. An example of the arithmetic unit 13B is an FPGA. In addition, various processors such as CPUs and MPUs, and integrated circuits such as ASICs may be used as the arithmetic unit 13B.

[0042] Based on instructions from the arithmetic unit 13B, the framer IC 12B transmits the recovery information received from the arithmetic unit 13B to the transponder device 20A via the E / O converter 11B. The framer IC 12B also performs demapping and over-optical processing on the input signal.

[0043] The E / O converter 11B converts the input electrical signal into an optical signal. When the E / O converter 11B receives recovery information from the framer IC 12B, it transmits the recovery information to the transponder device 20A.

[0044] Figure 6 is a sequence diagram showing an example of processing performed in a communication system 1 according to an exemplary embodiment. Below, an example of what happens when an input signal failure occurs in the transponder device 10A will be described.

[0045] In step S1, the fault detection unit 101 of the transponder device 10A detects a fault in the input signal to the transponder device 10A. In step S2, the optical module control unit 102 of the transponder device 10A causes the optical module 15A of the transponder device 10A to perform a reset process. In step S3, the transmission unit 103 of the transponder device 10A transmits recovery information to the transponder device 10B indicating that the transponder device 10A has recovered from the fault.

[0046] When the transponder device 10B receives recovery information from the transponder device 10A, in step S4, the index value calculation unit 113 of the transponder device 10B calculates an index value indicating the quality of the transmission signal received by the transponder device 10B from the transponder device 10A. For example, the index value calculation unit 113 can calculate the index value using the code error rate of the transmission signal indicating the recovery information, based on formula 1.

number

[0047] In step S5, the index value determination unit 114 of the transponder device 10B determines whether the index value calculated by the index value calculation unit 113 of the transponder device 10B is within a predetermined range. If the calculated index value is outside the predetermined range, in step S6, the optical module control unit 112 of the transponder device 10B causes the optical module 15B of the transponder device 10B to perform a reset process. If the calculated index value is within the predetermined range, the optical module control unit 112 does not cause the optical module 15B of the transponder device 10B to reset. In this embodiment, the transponder device 10B repeatedly executes the processes in steps S4 to S6 until the calculated index value is outside the predetermined range.

[0048] In step S7, the optical output determination unit 115 of the transponder device 10B determines the optical output status of the client block of the transponder device 10B. If the optical output status of the client block is ON, the transponder device 10B transmits recovery information to the transponder device 20A in step S8.

[0049] When the transponder device 20A receives recovery information from the transponder device 10B, it forwards the recovery information to the transponder device 20B in step S9.

[0050] When the transponder device 20B receives recovery information from the transponder device 20A, in step S10, the index value calculation unit 113 of the transponder device 20B calculates an index value that indicates the quality of the transmission signal received by the transponder device 20B from the transponder device 20A.

[0051] In step S11, the index value determination unit 114 of the transponder device 20B determines whether the index value calculated by the index value calculation unit 113 of the transponder device 20B is within a predetermined range. If the calculated index value is outside the predetermined range, in step S12, the optical module control unit 112 of the transponder device 20B causes the optical module 15B of the transponder device 20B to perform a reset process. If the calculated index value is within the predetermined range, the optical module control unit 112 does not cause the optical module 15B of the transponder device 20B to reset. In this embodiment, the transponder device 20B repeatedly executes the processes in steps S10 to S12 until the index value is outside the predetermined range.

[0052] In step S13, the optical output determination unit 115 of the transponder device 20B determines the optical output status of the client block of the transponder device 20B. If the optical output status of the client block is OFF, the process shown in Figure 6 ends. If the optical output status of the client block is ON, the transponder device 20B transmits recovery information to a transponder device located adjacent to it on the downstream side.

[0053] Figure 7 is a flowchart illustrating an example of a process performed by transponder devices such as transponder devices 10B and 20B according to an exemplary embodiment. The following explanation will use transponder device 10B as an example.

[0054] In step S101, the reception determination unit 111 of the transponder device 10B determines whether or not recovery information has been received. If it is determined that recovery information has not been received (NO), the process in step S101 is executed again. On the other hand, if it is determined that recovery information has been received (YES), in step S102, the index value calculation unit 113 calculates an index value indicating the quality of the transmission signal received by the transponder device 10B.

[0055] In step S103, the index value determination unit 114 determines whether the calculated index value is within a predetermined range. If it is determined that the calculated index value is outside the predetermined range (NO), in step S104, the optical module control unit 112 resets the optical module 15B, and the process returns to step S102.

[0056] On the other hand, if it is determined that the calculated index value is within a predetermined range (YES), the process branches to step S105. In step S105, the optical output determination unit 115 determines the optical output status of the client block of the transponder device 10B. If it is determined that the optical output of the client block is OFF, the process in Figure 7 ends. On the other hand, if it is determined that the optical output of the client block is ON, in step S106, the transmission unit 116 transmits recovery information to the transponder device 20A, which is located adjacent to the downstream side of the transponder device 10B, and the process in Figure 7 ends.

[0057] Figure 8 shows the main components of transponder devices 10A and 10B according to an exemplary embodiment. Transponder device 10A includes an optical module 15A, a fault detection unit 101, an optical module control unit 102, and a transmission unit 103. Transponder device 10B includes an optical module 15B, an optical module control unit 112, an index value calculation unit 113, and an index value determination unit 114.

[0058] The optical module 15B processes the transmission signal received from a transponder device located adjacent to it on the upstream side. The index value calculation unit 113 performs an index value calculation process to calculate an index value indicating the quality of the transmission signal received from the transponder device located adjacent to it on the upstream side. The index value determination unit 114 performs an index value determination process to determine whether the calculated index value is within a predetermined range when it receives recovery information that the transponder device located upstream to it has recovered from a fault in the input signal to the transponder device. If the optical module control unit 112 determines that the calculated index value is not within a predetermined range, it performs a reset process on the optical module 15B to cause it to receive a new transmission signal from the transponder device located adjacent to it on the upstream side of the transponder device 10B.

[0059] By adopting this configuration, transponder device 10B can receive and process a new transmission signal if the quality of the transmission signal already received by transponder device 10B does not meet a certain quality standard when the transponder device located upstream recovers from an input signal failure. Therefore, the impact of failures in the transmission signal input to transponder device 10B can be suppressed.

[0060] Furthermore, the default range is determined individually based on the environmental conditions of the optical communication cable connected to each transponder device. Therefore, each transponder device can evaluate the quality of the transmission signal it receives according to the installation and environmental conditions of the individual optical communication cable.

[0061] Furthermore, the transponder device 10B further includes a transmitting unit 116 that, upon receiving recovery information, transmits the recovery information to another transponder device located adjacent to it downstream. This allows the other transponder device that receives the recovery information to perform the index value calculation process, index value determination process, and reset process described above. Therefore, the impact of failures in the transmission signals input to transponder devices located downstream of transponder device 10B can be suppressed, not just to transponder device 10B. Thus, in a communication system in which multiple transponder devices are connected in series, the impact of failures in the transmission signals input to each transponder device can be prevented.

[0062] Furthermore, the reset process includes discarding transmission signals already received by the optical modules 15A and 15B. This discards transmission signals that do not meet a certain quality standard, such as weak transmission signals or transmission signals equivalent to noise, thereby suppressing the impact of faults in the transmission signals input to the transponder devices 10B, 20A, and 20B.

[0063] Furthermore, the transponder device 10B repeatedly performs the index value calculation process, index value determination process, and reset process until the index value falls within a predetermined range. This allows the transponder device 10B to receive transmission signals that meet a certain quality standard and suppresses the impact of faults in the transmission signals input to the transponder device 10B.

[0064] In the above example, program 110 includes a set of instructions (or software code) for causing the computer to perform one or more of the functions described in the embodiment when loaded into the computer. Program 110 may be stored in a non-temporary computer-readable medium or a physical storage medium. Examples, but not limited, of computer-readable mediums or physical storage media include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technologies, CD-ROM, digital versatile disk (DVD), Blu-ray® disc or other optical disc storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices. The program may be transmitted over a temporary computer-readable medium or a communication medium. Examples, but not limited, of temporary computer-readable mediums or communication media include propagating signals of electrical, optical, acoustic or other forms.

[0065] This disclosure is not limited to the embodiments described above, and may be modified as appropriate without departing from the spirit of this disclosure.

[0066] For example, in another embodiment, the index value may be the difference between a first index value indicating the quality of the transmission signal, calculated based on the code error rate of the transmission signal received by the device itself, and a second index value indicating the quality of the transmission signal, calculated based on the code error rate of the transmission signal received by any one of the transponder devices located upstream of the device itself. Transponder devices located upstream of the device itself include not only transponder devices located adjacent to the upstream side of the device itself, but also transponder devices located further upstream of such adjacent transponder devices. For example, if the device itself is transponder device 20B, transponder devices located upstream of transponder device 20B include transponder device 20A, as well as transponder devices 10A and 10B. Any one of these upstream transponder devices transmits the second index value to a transponder device located downstream of it that is to calculate the first index value. Then, when the transponder device that is to calculate the index value receives the second index value, the index value calculation unit 113 calculates the difference between the first index value and the second index value, and the index value determination unit 114 determines whether or not the calculated difference in index values ​​is within a predetermined range.

[0067] Furthermore, in other embodiments, the transponder devices 10A and 20A located on the upstream side of a pair of transponder devices can execute the program 110 described above. In this embodiment, transponder devices 10A and 20A not only transfer recovery information but also perform the processing described later. The following explanation will use transponder device 10A as an example.

[0068] In this embodiment, the arithmetic unit 14A of the transponder device 10A calculates an index value indicating the quality of the transmission signal received from a transponder device located adjacent to the upstream side of the transponder device 10A. Furthermore, when the arithmetic unit 14A receives recovery information indicating that the transponder device located upstream of the transponder device 10A has recovered from an input signal fault, it determines whether the calculated index value is within a predetermined range. If it is determined that the calculated index value is not within the predetermined range, the arithmetic unit 14A causes the optical module 15A to perform a reset process. As a result, the optical module 15A can receive a new transmission signal and transmit a new transmission signal that meets a certain quality standard to the transponder device 10B.

[0069] Some or all of the above embodiments may also be described as follows, but are not limited to the following: (Note 1) A communication system in which multiple communication devices are connected in series via optical communication cables, The first communication device and At least one second communication device located downstream of the first communication device and Includes, The first communication device is, A first optical module that processes transmission signals received from a communication device located adjacent to the upstream side of its own device, A fault detection unit for detecting faults in the input signal to the first communication device, When the fault detection unit detects a fault in the input signal, the first optical module control unit causes the first optical module to perform a reset process to receive a new input signal, The first optical module performs the reset process, and when the first communication device recovers from the input signal failure, the first optical module performs the reset process, and the first communication device recovers from the failure, the first optical module includes a transmitting unit that transmits recovery information to the second communication device indicating that the first communication device has recovered from the failure. The second communication device is A second optical module that processes transmission signals received from a communication device located adjacent to the upstream side of its own device, An index value calculation unit that performs an index value calculation process to calculate an index value indicating the quality of a transmission signal received from a communication device located adjacent to the upstream side of the device, An index value determination unit that, upon receiving the recovery information, executes an index value determination process to determine whether the index value calculated by the index value calculation unit is within a predetermined range, If the index value determination unit determines that the index value is not within the predetermined range, the second optical module control unit causes the second optical module to perform a reset process that causes it to receive a new transmission signal, Communication system. (Note 2) The aforementioned index value determination unit is: The device determines whether a first index value indicating the quality of the transmission signal received by the device is within the predetermined range, or The communication system described in Appendix 1, which determines whether the difference between the first index value and a second index value indicating the quality of a transmission signal received by any one communication device located upstream of the device is within the predetermined range. (Note 3) The communication system as described in Appendix 1 or 2, wherein the predetermined range is a range individually determined according to the environmental conditions of each optical communication cable connected to each of the communication devices that determine the index value. (Note 4) The communication system as described in Appendix 3, wherein the predetermined range is a range in which the upper and lower limits are the maximum and minimum values ​​of the index value of the transmission signal when there is no fault in the transmission signal received through the optical communication cable installed in the actual installation environment. (Note 5) When the communication system includes a plurality of the second communication devices, The communication system according to Appendix 1 or 2, wherein the second communication device further includes a transmitting unit that, upon receiving the recovery information, transmits the recovery information to another second communication device located adjacent to it on the downstream side. (Note 6) The communication system according to Appendix 1 or 2, wherein the reset process includes a process of discarding a transmission signal already received by the optical module. (Note 7) The second communication device is a communication system according to Appendix 1 or 2, which repeatedly performs the index value calculation process, the index value determination process, and the reset process until the index value falls within the predetermined range. (Note 8) A communication device connected in series with other communication devices via an optical communication cable, An optical module that processes transmission signals received from a communication device located adjacent to the upstream side of its own device, An index value calculation unit that calculates an index value indicating the quality of the transmission signal received from a communication device located adjacent to the upstream side, When a communication device located upstream of the device receives recovery information indicating that it has recovered from an input signal failure, an index value determination unit determines whether the index value calculated by the index value calculation unit is within a predetermined range. If the indicator value determination unit determines that the indicator value is not within the predetermined range, the optical module control unit causes the optical module to perform a reset process that causes it to receive a new transmission signal. A communication device that includes this. (Note 9) The aforementioned index value determination unit is: The device determines whether a first index value indicating the quality of the transmission signal received by the device is within the predetermined range, or A communication device as described in Appendix 8, which determines whether the difference between the first index value and a second index value indicating the quality of a transmission signal received by any one communication device located upstream of its own device is within the predetermined range. (Note 10) A method performed by a communication device connected in series with other communication devices via an optical communication cable, An index value indicating the quality of the transmission signal received from a communication device located adjacent to the upstream side is calculated. When a communication device located upstream of the device receives recovery information indicating that it has recovered from an input signal failure, it determines whether the calculated index value is within a predetermined range. If it is determined that the calculated index value is not within the predetermined range, the device will cause the optical module that processes the transmission signal to perform a reset process to receive a new transmission signal. method. (Note 11) For a communication device connected in series with other communication devices via an optical communication cable, The steps include: calculating an index value indicating the quality of the transmission signal received from a communication device located adjacent to the upstream side of the device; When a communication device located upstream of the device receives recovery information indicating that it has recovered from an input signal failure, the device determines whether the calculated index value is within a predetermined range. If it is determined that the calculated index value is not within the predetermined range, the device performs a reset process to cause the optical module that processes the transmission signal to receive a new transmission signal. A program that executes the command. [Explanation of Symbols]

[0070] 1. Communication System 10A Transponder Device 10B Transponder Device 11A O / E converter 11B E / O converter 12A Framer IC 12B Framer IC 13A arithmetic unit 13B Arithmetic unit 14A arithmetic unit 14B Arithmetic unit 15A Optical Module 15B Optical Module 16B storage device 20A Transponder Device 20B Transponder Device 30 Optical communication cables 101 Fault detection unit 102 Optical Module Control Unit 103 Transmitter 110 Programs 111 Reception determination unit 112 Optical Module Control Unit 113 Indicator Value Calculation Unit 114 Indicator Value Determination Unit 115 Light output determination unit 116 Transmitter

Claims

1. A communication system in which multiple communication devices are connected in series via optical communication cables, The first communication device and At least one second communication device located downstream of the first communication device and Includes, The first communication device is A first optical module that processes transmission signals received from a communication device located adjacent to the upstream side of its own device, A fault detection unit for detecting faults in the input signal to the first communication device, When the fault detection unit detects a fault in the input signal, the first optical module control unit causes the first optical module to perform a reset process to receive a new input signal, The first optical module performs the reset process, and when the first communication device recovers from the input signal failure, the first optical module performs the reset process, and the first communication device recovers from the failure, the first optical module includes a transmission unit that transmits recovery information to the second communication device indicating that the first communication device has recovered from the failure. The second communication device is A second optical module that processes transmission signals received from a communication device located adjacent to the upstream side of its own device, An index value calculation unit that performs an index value calculation process to calculate an index value indicating the quality of a transmission signal received from a communication device located adjacent to the upstream side of the device, An index value determination unit that, upon receiving the recovery information, executes an index value determination process to determine whether the index value calculated by the index value calculation unit is within a predetermined range, The second optical module control unit includes, if the index value determination unit determines that the index value is not within the predetermined range, the second optical module control unit causes the second optical module to perform a reset process that causes it to receive a new transmission signal. Communication system.

2. The aforementioned index value determination unit is: The device determines whether the first index value indicating the quality of the transmission signal received by the device is within the predetermined range, or The communication system according to claim 1, which determines whether the difference between the first index value and a second index value indicating the quality of a transmission signal received by any one communication device located upstream of the device is within the predetermined range.

3. The communication system according to claim 1 or 2, wherein the predetermined range is a range individually determined according to the environmental conditions of the optical communication cable connected to the second communication device for determining the index value.

4. The communication system according to claim 3, wherein the predetermined range is a range in which the upper and lower limits are the maximum and minimum values ​​of the index value of the transmission signal when there is no problem with the transmission signal received through the optical communication cable installed in the actual installation environment.

5. When the communication system includes a plurality of the second communication devices, The communication system according to claim 1 or 2, wherein the second communication device further includes a transmitting unit that, upon receiving the recovery information, transmits the recovery information to another second communication device located adjacent to it on the downstream side.

6. The communication system according to claim 1 or 2, wherein the reset process includes a process of discarding a transmission signal already received by the optical module.

7. A communication device connected in series with other communication devices via an optical communication cable, An optical module that processes transmission signals received from a communication device located adjacent to the upstream side of its own device, An index value calculation unit that calculates an index value indicating the quality of the transmission signal received from a communication device located adjacent to the upstream side, When a communication device located upstream of the device receives recovery information indicating that it has recovered from an input signal failure, an index value determination unit determines whether the index value calculated by the index value calculation unit is within a predetermined range. If the indicator value determination unit determines that the indicator value is not within the predetermined range, the optical module control unit causes the optical module to perform a reset process that causes it to receive a new transmission signal. A communication device that includes this.

8. The aforementioned index value determination unit is: Determine whether the first indicator value indicating the quality of the transmission signal received by the device is within the predetermined range, or The communication device according to claim 7, which determines whether the difference between the first index value and a second index value indicating the quality of a transmission signal received by any one communication device located upstream of the device is within the predetermined range.

9. A method performed by a communication device connected in series with other communication devices via an optical communication cable, An index value indicating the quality of the transmission signal received from a communication device located adjacent to the upstream side is calculated. When a communication device located upstream of the device receives recovery information indicating that it has recovered from an input signal failure, it determines whether the calculated index value is within a predetermined range. If it is determined that the calculated index value is not within the predetermined range, the device will cause the optical module that processes the transmission signal to perform a reset process to receive a new transmission signal. method.

10. For a communication device connected in series with other communication devices via an optical communication cable, The steps include: calculating an index value indicating the quality of the transmission signal received from a communication device located adjacent to the upstream side of the device; When a communication device located upstream of the device receives recovery information indicating that it has recovered from an input signal failure, the device determines whether the calculated index value is within a predetermined range. If it is determined that the calculated index value is not within the predetermined range, the device performs a reset process to cause the optical module that processes the transmission signal to receive a new transmission signal. A program that executes the command.

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