JP2019033504A - Receiver, transceiver, receiving method, and transceiving method - Google Patents

Abstract

To provide a receiver, transceiver, receiving method, and transceiving method that can detect difference in FEC types for failure place determination.SOLUTION: A receiver 20 in an OTN includes: an OTU frame detection unit 21 for receiving a transmitted signal and synchronization detecting a frame; an FEC decoding unit 22 for performing FEC decoding processing on the synchronization-detected frame and outputting an OTU frame; a first FAS error detection unit 31a for detecting a first bit error number of a FAS in the detected OTU frame; and a second FAS error detection unit 31b for detecting a second bit error number of the FAS in an OTU frame whose errors are corrected in the FEC decoding unit. It is determined whether a bit error rate calculated on the basis of the first FAS bit error number exceeds a bit error rate correctable by the FEC. If the bit error rate is less than a prescribed threshold value, a signal state determination unit 32 determines whether FEC types accord on the basis of the second bit error number.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an OTN (Optical Transport Network) receiving apparatus, transmitting / receiving apparatus, receiving method, and transmitting / receiving method.

  In the backbone network, signals based on various standards are transmitted and received. Among these signals, there is an OTN (Optical Transport Network), and various signals with different standards exist in the OTN. The reason is that, in OTN, a standard Reed Solomon code for error correction: RS (255, 239) (hereinafter referred to as G.709 FEC: Non-Patent Document 1) is used to provide higher error correction capability. This is because there are some that use various types of FEC (Forward Error Correction). For example, in Non-Patent Document 2, a plurality of types of FEC having different coding gain, processing delay, and redundancy are defined in transmission / reception of an OTN signal, and it is possible to select one corresponding to the application.

  Here, in the transmission / reception of the OTN signal, it is necessary to use the same FEC on the transmission side and the reception side. If the FEC type is different between the transmission side and the reception side, error correction is not normally performed on the reception side. Then, errors may be further superimposed on the receiving side by the FEC decoding process, and the signal may be interrupted. Therefore, when transmission / reception of an OTN signal causes transmission characteristics to deteriorate due to a difference in FEC type and the signal is not transmitted, it is possible to determine whether the cause of the disconnection is due to a difference in the FEC type or a problem such as a failure in the transmission path. It cannot be done, and it takes time to isolate the cause of the failure.

  As a method for avoiding the mismatch of FEC settings, there is a transmission method described in Patent Document 1. According to this transmission method, a main signal frame is generated and transmitted by superimposing a control signal including main signal setting information on the main signal, and the control signal includes code type information indicating the type of error correction code. Yes.

JP-A-2015-002474

ITU-T G. 709 / Y. 1331 ITU-T G. 975.1

According to the transmission method described in Patent Document 1, a special control signal is superimposed on the main signal in order to prevent signal type mismatch between the transmitting station and the receiving station. For this reason, in this transmission / reception system, it is necessary to use a special device in the transmission device and the reception device, and the capital investment is enormous for applying to existing facilities.
The present invention provides a receiving device, a transmitting / receiving device, a receiving method, and a transmitting / receiving method capable of detecting each FEC type and detecting a failure in a network even if devices using different types of FEC are connected in an existing OTN facility The purpose is to provide.

One aspect of the present invention is a receiving device in OTN (Optical Transport Network),
An OTU (Optical channel Transport Unit) frame detection unit that receives a transmitted signal and detects a frame synchronously;
An FEC decoding unit that performs FEC (Forward Error Correction) decoding processing on the synchronously detected frame and outputs an OTU (Optical channel Transport Unit) frame;
A first FAS error detection unit for detecting a first bit error number of FAS (Frame Alignment Signal) in the OTU frame detected by the OTU frame detection unit;
A second FAS error detection unit for detecting a second number of FAS bit errors in the OTU frame that has been error-corrected by the FEC decoding unit;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, A signal state determination unit that determines whether the FEC type matches based on the number of bit errors of 2.

One aspect of the present invention is a transmission / reception device in OTN (Optical Transport Network),
An OTU (Optical channel Transport Unit) frame detection unit that receives a transmitted signal and detects a frame synchronously;
An FEC decoding unit that performs FEC (Forward Error Correction) decoding processing on the synchronously detected frame and outputs an OTU (Optical channel Transport Unit) frame;
A first FAS error detection unit for detecting a first bit error number of FAS (Frame Alignment Signal) in the OTU frame detected by the OTU frame detection unit;
A second FAS error detection unit for detecting a second number of FAS bit errors in the OTU frame that has been error-corrected by the FEC decoding unit;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, A signal state determination unit that determines the match of the FEC type based on the number of bit errors of 2,
An FEC setting unit that changes the setting of the FEC type in the FEC decoding unit based on the determination of the signal state determination unit;
A transmission unit that transmits a signal according to the changed FEC type in conjunction with the change of the setting of the FEC type by the FEC setting unit.

One aspect of the present invention is a reception method in OTN (Optical Transport Network),
Receiving the transmitted signal and detecting the frame synchronously;
Performing FEC (Forward Error Correction) decoding on the synchronously detected frame and outputting an OTU (Optical channel Transport Unit) frame;
Detecting a first bit error number of FAS (Frame Alignment Signal) in the detected OTU frame;
Detecting a second bit error number of FAS in the error-corrected OTU frame;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, And determining whether the FEC type matches based on the number of bit errors of 2.

One aspect of the present invention is a transmission / reception method in OTN (Optical Transport Network),
Receiving the transmitted signal and detecting the frame synchronously;
Performing FEC decoding on the synchronously detected frame and outputting an OTU (Optical channel Transport Unit) frame;
Detecting a first bit error number of FAS (Frame Alignment Signal) in the detected OTU frame;
Detecting a second bit error number of FAS in the error-corrected OTU frame;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, Determining a match of the FEC type based on the number of bit errors of 2,
An FEC setting unit that changes the setting of the FEC type based on the determination;
And causing the computer to execute a process having a step of transmitting a signal according to the changed FEC type in conjunction with the change of the setting of the FEC type.

One aspect of the present invention is a receiving device connected to a network or a circuit,
A synchronization detection unit that receives an FEC-encoded signal and detects a frame or codeword based on a fixed pattern for synchronization;
An FEC decoding unit that performs FEC decoding on the synchronously detected frame or codeword and outputs the frame or codeword;
A first synchronization pattern error detection unit that detects a first bit error number of a fixed pattern for synchronization in the frame or the codeword detected by the synchronization detection unit;
A second synchronization pattern error detection unit that detects a second number of bit errors of the fixed pattern for synchronization in the frame or the codeword that has been error-corrected by the FEC decoding unit;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, A signal state determination unit that determines whether the FEC type matches based on the number of bit errors of 2.

One aspect of the present invention is a reception method of a reception device connected to a network or a circuit,
Receiving an FEC-encoded signal and detecting a frame or codeword synchronously based on a fixed pattern for synchronization;
Performing FEC decoding on the synchronously detected frame or codeword and outputting the frame or codeword;
Detecting a first number of bit errors in a fixed pattern for synchronization in the detected frame or codeword;
Detecting a second number of bit errors in a fixed pattern for synchronization within the error-corrected frame or codeword;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, And determining whether the FEC type matches based on the number of bit errors of 2.

  According to the receiving apparatus, transmitting / receiving apparatus, receiving method, and transmitting / receiving method according to the present invention, even if apparatuses using different types of FEC are connected in the existing OTN equipment, each FEC type is detected, and a failure in the network is also caused. It can be detected.

It is a block diagram which shows the structure of a general OTN transmission / reception system. It is a figure which shows the structure of the OTU frame transmitted. It is a figure which shows the problem of a general OTN transmitter and a receiver. It is a block diagram which shows the structure of the receiver concerning 1st Embodiment. It is a flowchart explaining operation | movement of a receiver. It is a block diagram which shows the structure of the transmission / reception apparatus concerning 2nd Embodiment.

[First Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the device configuration of a general OTN transmission / reception device and its problem will be described.

  As shown in FIG. 1, a general OTN transmission / reception system 100 includes an OTN transmission device 1 that inputs a client signal and transmits an OTN signal, and an OTN signal that is connected to the OTN transmission device 1 via a transmission line 30. It comprises an OTN receiver 2 that receives and outputs a client signal.

  The OTN transmission apparatus 1 includes an OTU (Optical channel Transport Unit) frame generation unit 11 connected to the upstream side, and an FEC encoding unit 12 connected to the OTU frame generation unit 11. The FEC encoding unit 12 is connected to the transmission path 3 on the downstream side. The OTU frame generation unit 11 of the OTN transmission apparatus 1 accommodates the input client signal in the OTU frame. The FEC encoder 12 has a function of adding FEC to the OTU frame generated by the OTU frame generator 11. The OTU frame includes an overhead part, a payload part, and an FEC part, and a fixed pattern FAS (Frame Alignment Signal) and SM (Section Monitoring) for frame synchronization are defined in the overhead part (see FIG. 2).

  The OTN receiving apparatus 2 includes an OTU frame detection unit 21 connected to the transmission path 3 on the upstream side, an FEC decoding unit 22 connected to the OTU frame detection unit 21, and an OTU frame processing unit 23 connected to the FEC decoding unit 22. It consists of. The OTU frame detection unit 21 of the OTN reception apparatus 2 performs frame synchronization detection using FAS, which is a fixed pattern for frame synchronization.

  The FEC decoding unit 22 performs FEC decoding processing on the synchronously detected frame. Thereby, it is possible to correct a bit error generated in the transmission path 3. The FEC decoding unit 22 calculates the number of FEC correction bits and the number of uncorrectable symbols. The OTU frame processing unit 23 extracts a client signal from the OTU frame output from the FEC decoding unit 22 and outputs the client signal. Further, SM (Section Monitoring) overhead is defined in the OTU frame (see FIG. 2). As a result, the OTU frame processing unit 23 can check the connection source and the connection destination using the TTI (Trail Trace Identifier) in the overhead.

  Here, a problem in the existing OTN transmission / reception apparatus will be described. As described above, there are a plurality of types of FECs used in the OTN, and the OTN transmission device 1 and the OTN reception device 2 must use the same type of FEC.

  As shown in FIG. 3, description will be given by taking as an example a network configured by the OTN transmission device 1 and the OTN reception devices 2A, 2B, and 2C. In the OTN transmission / reception apparatus 200, a plurality of OTN reception apparatuses 2A, 2B, and 2C are connected to the OTN transmission apparatus 1 via a ROADM (reconfigurable optical add / drop multiplexer) apparatus 4 that branches the transmission path 3. The OTN transmission device 1 and the ROADM device 4 are connected by a transmission line 3, and the ROADM device 4 and the OTN reception devices 2A, 2B, and 2C are connected by transmission lines 3A, 3B, and 3C, respectively. The ROADM device 4 has an optical switching function, and selects a connection destination of the OTN transmission device 1 from the OTN reception device 2A, the OTN reception device 2B, or the OTN reception device 2C.

  It is assumed that the OTN transmitter 1 and the OTN receivers 2A and 2C use G.709 FEC, and the OTN receiver 2B uses G.975.1 I.4 FEC. For example, consider a case where a failure occurs in the transmission line 3C. At this time, when the OTN transmission device 1 and the OTN reception device 2C are connected, the bit error rate of the OTN reception device 2C device exceeds the error correction range of G.709 FEC. Here, A: operation when the OTN transmitter 1 and the OTN receiver 2A are connected, B: operation when the OTN transmitter 1 and the OTN receiver 2B are connected, and C: OTN transmitter 1 and the OTN receiver 2C. Let's consider the operation when each is connected.

A: When the OTN transmission device 1 and the OTN reception device 2A are connected In this case, both the transmission device and the reception device use G.709 FEC and can correct a bit error in the transmission path. In this state, it is possible to conduct the signal and confirm the connection source / connection destination by the above-described TTI.

B: When the OTN transmitter 1 and the OTN receiver 2B are connected Since the different types of FEC are set in the OTN transmitter 1 and the receiver 2B, the bit error rate deterioration caused by transmitting the transmission paths 3 and 3B is recovered. In addition to being unable to do so, errors are further superimposed in the FEC decoding process of the FEC decoding unit 22, and as a result, the signal is interrupted. In addition, various overheads are prepared for the OTU frame. In this case, since errors due to FEC decoding are superimposed as described above, they cannot be used.

C: When the OTN transmission device 1 and the OTN reception device 2C are connected. In this case, although the FEC type matches, the bit error rate deterioration due to the failure of the transmission path 3C can be corrected by FEC decoding as described above. Is exceeded and the signal is interrupted.

  As described above, in OTN, there is no detection means when a device using a different type of FEC is connected. In the case of B and C described above, the cause of the signal interruption is a factor such as a transmission path. It may not be possible to determine whether it is due to the difference in the FEC type.

[First Embodiment]
Next, an embodiment according to the OTN receiver of the present invention will be described with reference to the drawings.

  As shown in FIG. 4, the OTN receiver 20 is obtained by adding components (FAS error detectors 31a and 31b and a signal state determiner 32) to the above-described OTN receiver 2 (see FIG. 1). Specifically, the OTN receiver 20 includes an OTU frame detection unit 21 that performs frame synchronization of a signal input from the transmission path 3, and an FEC decoding unit that performs an FEC decoding process on the signal output from the OTU frame detection unit 21. 22 and an OTU frame processing unit 23 for processing the FEC-decoded signal. A (first) FAS error detection unit 31 a is connected between the OTU frame detection unit 21 and the FEC decoding unit 22. A (second) FAS error detection unit 31 b is connected between the FEC decoding unit 22 and the OTU frame processing unit 23. The FAS error detection unit 31 a and the FAS error detection unit 31 b are connected to the signal state determination unit 32.

  The FAS error detection unit 31a calculates the number of errors in the FAS signal of the signal output from the OTU frame detection unit 21. The FAS error detection unit 31b calculates the number of errors in the FAS signal after FEC decoding. The signal state determination unit 32 determines the signal state based on the (first and second) bit error numbers a and b calculated by the FAS error detection units 31a and 31b.

  Next, the operation of the OTN receiver 20 will be described. For the signal received from the transmission path 3, the OTU frame detection unit 21 detects frame synchronization. The frame-synchronized OTU signal is sent to the FEC decoding unit 22 and the FAS error detection unit 31a. The FEC decoding unit 22 performs FEC decoding processing, and sends an error-corrected signal to the OTU frame processing unit 23 and the FAS error detection unit 31b.

  The FAS error detection units 31 a and 31 b compare the expected FAS pattern with the FAS of the received OTU frame, and send the number of bit errors to the signal state determination unit 32. As an example, consider a case where the FAS of the received OTU frame is “E6F6F6282828h” when the expected FAS pattern is “F6F6F62828228h”. In this case, the number of bit errors is 1 bit. The signal state determination unit 32 detects FEC type match / mismatch and bit error rate excess from the number of FAS bit errors sent from the FAS error detection unit 31a and the FAS error detection unit 31b.

  Here, the FEC type match indicates that the FEC method used in the OTN transmission device 1 (see FIG. 1) matches the FEC method used in the OTN reception device 2. The FEC type mismatch indicates that the FEC scheme used in the OTN transmission apparatus 1 (see FIG. 1) and the FEC scheme used in the OTN reception apparatus 2 do not match. The bit error rate excess means that the bit error rate in the OTN receiver 2 exceeds the bit error rate that can be corrected by the FEC due to the state of the transmission line 3 or a failure factor in the network such as the failure of the OTN transmitter 1. Indicates that

As shown in FIG. 5, the signal state determination unit 32 first calculates the bit error rate α from the (first) bit error number a sent from the FAS error detection unit 31a, and sets a predetermined threshold value. Comparison is performed (S100). Here, the bit error rate α is calculated by the following equation.
Bit error rate α = number of bit errors a ÷ number of synchronization pattern bits The bit error rate may be calculated based on the number of bit errors in a plurality of frames. For example, when calculating based on the number of bit errors of N frames, the following formula is used.
Bit error rate α = number of bit errors a ÷ (number of synchronization pattern bits × N)

  The signal state determination unit 32 compares the bit error rate α with a preset threshold value, and if the bit error rate α is a value equal to or greater than the threshold value (S100: N), determines that the bit error rate is exceeded (S104). ). At this time, the signal state determination unit 32 determines that there is a failure in the network due to factors such as the state of the transmission path 3 or the failure of the OTN transmission device 1. This threshold is set based on the FEC method used in the FEC decoder 22 and the expected bit error rate after FEC decoding. For example, consider a case where the FEC decoding unit 22 uses G.709 FEC defined in Non-Patent Document 1 and the bit error rate after FEC decoding is 1.0E-12.

  The input bit error rate at which the output bit error rate of G.709 FEC is 1.0E-12 is approximately 2.0E-4 (see Non-Patent Document 2 Figure I.7 / G.975.1). Set 4. If the bit error rate α is larger than this threshold value, the effect of error correction by FEC decoding cannot be expected, so it is determined that the bit error rate is exceeded. When the bit error rate α is smaller than the threshold (S100: Y), processing for determining whether the FEC type matches or does not match is performed (S101).

  Next, when the bit error number b sent from the FAS error detection unit 31b is 0 (S101: N), the signal state determination unit 32 assumes that the FEC decoding has been performed normally and the FEC type matches. (S103). When the bit error count b is greater than 0 (S101: Y), the signal state determination unit 32 determines that the FEC type does not match because error correction is not possible despite the bit error rate being error correctable. (S102). In order to improve the accuracy of FEC type match / mismatch detection, the bit error rate α and the bit error count b may be determined across a plurality of OTU frames.

  The present invention can also be applied to signals other than OTN as long as the signal has a frame synchronization pattern or a codeword synchronization pattern and has an FEC correction function including this synchronization pattern. In this case, the receiving apparatus is configured to be connected to a network or a circuit, and the OTU frame detecting unit 21 receives an FEC-encoded signal and generates a frame or codeword based on a fixed pattern for synchronization. You may comprise as a synchronous detection part which detects synchronously.

  Then, the FEC decoding unit 22 may be configured to perform the FEC decoding process on the synchronously detected frame or codeword and output the frame or codeword. Then, the FAS error detection unit (first error detection unit) 31a detects the first bit error number of the fixed pattern for synchronization in the frame or codeword detected by the synchronization detection unit. You may comprise as a synchronous pattern error detection part. Then, the FAS error detection unit (second error detection unit) 31b detects the second number of bit errors of the fixed pattern for synchronization in the frame or codeword that has been error-corrected by the FEC decoding unit. You may comprise as a synchronous pattern error detection part.

  As described above, according to the OTN receiver 20, whether or not the FEC type used in the OTN transmitter 1 matches the FEC type used in the OTN receiver 2 by determining the received signal. Can be detected. Further, according to the OTN receiver 20, it is possible to detect a failure in the network such as the state of the transmission path 3 or the failure of the OTN transmitter 1. Thereby, according to the OTN receiving apparatus 20, even if apparatuses using different types of FEC are connected in the existing OTN equipment, the respective FEC types can be detected.

[Second Embodiment]
Note that the present invention is not limited to the first embodiment, and can be modified as appropriate without departing from the spirit of the present invention. For example, a transmission / reception apparatus may be configured by adding a further configuration to the OTN reception apparatus 20. In the present embodiment, the same names and symbols are used for the same components as described above, and the same description is omitted as appropriate.

  As illustrated in FIG. 6, the transmission / reception device 30 transmits a signal to the OTN reception device 20 based on the FEC mismatch determination detected by the reception device 20 and the FEC setting of the FEC setting unit 33. And an OTN transmission unit (transmission device) 1 that performs the above operation. The FEC setting unit 33 changes the FEC setting of the FEC decoding unit 22 based on the FEC match / mismatch result detected by the signal state determination unit 32. For example, consider the case where the signal state determination unit 32 detects an FEC mismatch as described above. In this case, the FEC setting unit 33 sets the FEC method change to the FEC decoding unit 22.

  After setting the FEC method change, the FEC setting unit 33 confirms the FEC mismatch detection result, and ends the process if the FEC method matches can be confirmed. If the FEC mismatch is detected by the signal state determination unit 32 after changing the FEC method, the FEC setting unit 33 performs the FEC method change setting again. The FEC setting unit 33 continues the same processing until the signal state determination unit 32 detects the FEC match.

  As described above, according to the transmission / reception device 30, it is possible to automatically select the FEC type of the reception device by performing such processing. Further, according to the transmission / reception apparatus 30, the FEC method change setting can be performed from the FEC setting unit 33 to the FEC encoding unit 12 of the OTN transmission unit 1 based on the result of the automatic selection of the FEC method by the above processing. That is, the OTN transmission unit 1 transmits a signal with the FEC type changed in conjunction with the change of the FEC type setting by the FEC setting unit 33. As a result, when the transmission / reception apparatus 30 is arranged on the transmission side and the reception side to configure a transmission / reception system, any one of the transmission / reception apparatuses 30 changes the FEC scheme in the FEC encoding unit 12, so Can be matched.

  The FEC setting unit 33 may be added only to the OTN receiving apparatus 20 of the first embodiment, or the OTN receiving apparatus 20 may be configured to set the FEC method change to the FEC decoding unit 22.

  In the above embodiment, the present invention has been described as a hardware configuration, but the present invention is not limited to this. The present invention can also be realized by processing arbitrary processing by DSP (Digital Signal Processing). A program is executed on the DSP (Digital Signal Processor), and an FPGA (Field Programmable Gate Array) or ASIC (ASIC) is executed. This can be realized by executing with a logic circuit configured on (Application Specific Integrated Circuit).

  The program may be stored using various types of non-transitory computer readable media and supplied to a computer. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (for example, flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (for example, magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / W and semiconductor memory (for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (random access memory)) are included. The program may also be supplied to the computer by various types of transitory computer readable media. Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

  Although the present invention has been described with reference to the exemplary embodiments, the present invention is not limited to the above. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the invention.

For example, a part or all of the above-described embodiments can be described as in the following supplementary notes, but is not limited thereto.
(Appendix 1)
A receiving device in OTN (Optical Transport Network),
An OTU (Optical channel Transport Unit) frame detection unit that receives a transmitted signal and detects a frame synchronously;
An FEC decoding unit that performs FEC (Forward Error Correction) decoding processing on the synchronously detected frame and outputs an OTU frame;
A first FAS error detection unit for detecting a first bit error number of FAS (Frame Alignment Signal) in the OTU frame detected by the OTU frame detection unit;
A second FAS error detection unit for detecting a second number of FAS bit errors in the OTU frame that has been error-corrected by the FEC decoding unit;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, A signal state determination unit that determines FEC type match based on the number of bit errors of 2.
Receiver device.
(Appendix 2)
The signal state determination unit determines that the FEC type matches when the second number of bit errors is 0, and determines that the FEC type does not match when greater than 0.
The receiving device according to attachment 1.
(Appendix 3)
The signal state determination unit determines that a failure in the network occurs when the bit error rate is equal to or greater than the predetermined threshold;
The receiving device according to appendix 1 or 2.
(Appendix 4)
The receiving apparatus according to any one of appendices 1 to 3, further comprising: an FEC setting unit configured to change the setting of the FEC type in the FEC decoding unit based on the determination of the signal state determination unit.
(Appendix 5)
A transmission / reception device in OTN,
An OTU frame detector that receives a transmitted signal and detects a frame synchronously;
An FEC decoding unit that performs an FEC decoding process on the synchronously detected frame and outputs an OTU frame;
A first FAS error detection unit for detecting a first bit error number of FAS in the OTU frame detected by the OTU frame detection unit;
A second FAS error detection unit for detecting a second number of FAS bit errors in the OTU frame that has been error-corrected by the FEC decoding unit;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, A signal state determination unit that determines the match of the FEC type based on the number of bit errors of 2,
An FEC setting unit that changes the setting of the FEC type in the FEC decoding unit based on the determination of the signal state determination unit;
A transmission unit that transmits a signal according to the changed FEC type in conjunction with the change of the setting of the FEC type by the FEC setting unit.
Transmitter / receiver.
(Appendix 6)
The signal state determination unit determines that the FEC type matches when the second number of bit errors is 0, and determines that the FEC type does not match when greater than 0.
The transmission / reception device according to attachment 5.
(Appendix 7)
The signal state determination unit determines that a failure in the network occurs when the bit error rate is equal to or greater than the predetermined threshold;
The transmission / reception device according to appendix 5 or 6.
(Appendix 8)
A reception method in OTN,
Receiving the transmitted signal and detecting the frame synchronously;
Performing FEC decoding processing on the synchronously detected frame and outputting an OTU frame;
Detecting a first bit error number of FAS in the detected OTU frame;
Detecting a second bit error number of FAS in the error-corrected OTU frame;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, Determining whether the FEC type matches based on the number of bit errors of 2, and causing the computer to execute a process.
(Appendix 9)
The step of determining the match of the FEC type determines that the FEC type matches when the second number of bit errors is 0, and determines that the FEC type does not match when greater than 0.
The receiving method according to attachment 8.
(Appendix 10)
The step of determining the match of the FEC type determines that a failure has occurred in the network when the bit error rate is equal to or greater than the predetermined threshold.
The receiving method according to appendix 8 or 9.
(Appendix 11)
The receiving method according to any one of appendices 8 to 10, further including a step of changing the setting of the FEC type based on the determination of the step of determining the coincidence of the FEC type.
(Appendix 12)
A transmission / reception method in OTN,
Receiving the transmitted signal and detecting the frame synchronously;
Performing FEC decoding processing on the synchronously detected frame and outputting an OTU frame;
Detecting a first bit error number of FAS in the detected OTU frame;
Detecting a second bit error number of FAS in the error-corrected OTU frame;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, Determining a match of the FEC type based on the number of bit errors of 2,
Changing the setting of the FEC type based on the determination;
And a step of transmitting a signal according to the changed FEC type in conjunction with a change in the setting of the FEC type.
(Appendix 13)
The step of determining the match of the FEC type determines that the FEC type matches when the second number of bit errors is 0, and determines that the FEC type does not match when greater than 0.
The transmission / reception method according to attachment 12.
(Appendix 14)
The step of determining the match of the FEC type determines that a failure has occurred in the network when the bit error rate is equal to or greater than the predetermined threshold.
The transmission / reception method according to attachment 12 or 13.
(Appendix 15)
A receiving device connected to a network or circuit,
A synchronization detection unit that receives an FEC-encoded signal and detects a frame or codeword based on a fixed pattern for synchronization;
An FEC decoding unit that performs FEC decoding on the synchronously detected frame or codeword and outputs the frame or codeword;
A first synchronization pattern error detection unit that detects a first bit error number of a fixed pattern for synchronization in the frame or the codeword detected by the synchronization detection unit;
A second synchronization pattern error detection unit that detects a second number of bit errors of the fixed pattern for synchronization in the frame or the codeword that has been error-corrected by the FEC decoding unit;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, A signal state determination unit that determines FEC type match based on the number of bit errors of 2.
Receiver device.
(Appendix 16)
The signal state determination unit determines that the FEC type matches when the second number of bit errors is 0, and determines that the FEC type does not match when greater than 0.
The receiving device according to attachment 15.
(Appendix 17)
The signal state determination unit determines that a failure in the network occurs when the bit error rate is equal to or greater than the predetermined threshold;
The receiving device according to appendix 15 or 16.
(Appendix 18)
The receiving apparatus according to any one of supplementary notes 16 to 17, further comprising an FEC setting unit configured to change the setting of the FEC type in the FEC decoding unit based on the determination of the signal state determination unit.
(Appendix 19)
A receiving method of a receiving device connected to a network or a circuit,
Receiving an FEC-encoded signal and detecting a frame or codeword synchronously based on a fixed pattern for synchronization;
Performing FEC decoding on the synchronously detected frame or codeword and outputting the frame or codeword;
Detecting a first number of bit errors in a fixed pattern for synchronization in the detected frame or codeword;
Detecting a second number of bit errors in a fixed pattern for synchronization within the error-corrected frame or codeword;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, Determining whether the FEC type matches based on the number of bit errors of 2, and causing the computer to execute a process.
(Appendix 20)
The step of determining the match of the FEC type determines that the FEC type matches when the second number of bit errors is 0, and determines that the FEC type does not match when greater than 0.
The reception method according to attachment 19.
(Appendix 21)
The step of determining the match of the FEC type determines that a failure has occurred in the network when the bit error rate is equal to or greater than the predetermined threshold.
The reception method according to appendix 19 or 20.
(Appendix 22)
The receiving method according to any one of appendices 19 to 21, further comprising a step of changing the setting of the FEC type based on the determination of the step of determining whether the FEC type matches.

DESCRIPTION OF SYMBOLS 1 Transmission apparatus 2 Reception apparatus 2A, 2B, 2C Reception apparatus 3 Transmission path 3A, 3B, 3C Transmission path 4 ROADM apparatus 11 OTU frame generation part 12 FEC encoding part 20 OTN reception part 21 OTU frame detection part 22 FEC decoding part 23 OTU frame processing unit 30 Transmission / reception device 31a (first) FAS error detection unit 31b (second) FAS error detection unit 32 Signal state determination unit 33 FEC setting unit 100 Transmission / reception system

Claims (10)

A receiving device in OTN (Optical Transport Network),
An OTU (Optical channel Transport Unit) frame detection unit that receives a transmitted signal and detects a frame synchronously;
An FEC decoding unit that performs FEC (Forward Error Correction) decoding processing on the synchronously detected frame and outputs an OTU frame;
A first FAS error detection unit for detecting a first bit error number of FAS (Frame Alignment Signal) in the OTU frame detected by the OTU frame detection unit;
A second FAS error detection unit for detecting a second number of FAS bit errors in the OTU frame that has been error-corrected by the FEC decoding unit;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, A signal state determination unit that determines FEC type match based on the number of bit errors of 2.
Receiver device. The signal state determination unit determines that the FEC type matches when the second number of bit errors is 0, and determines that the FEC type does not match when greater than 0.
The receiving device according to claim 1. The signal state determination unit determines that a failure in the network occurs when the bit error rate is equal to or greater than the predetermined threshold;
The receiving device according to claim 1 or 2. A transmission / reception device in OTN,
An OTU frame detector that receives a transmitted signal and detects a frame synchronously;
An FEC decoding unit that performs an FEC decoding process on the synchronously detected frame and outputs an OTU frame;
A first FAS error detection unit for detecting a first bit error number of FAS in the OTU frame detected by the OTU frame detection unit;
A second FAS error detection unit for detecting a second number of FAS bit errors in the OTU frame that has been error-corrected by the FEC decoding unit;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, A signal state determination unit that determines the match of the FEC type based on the number of bit errors of 2,
An FEC setting unit that changes the setting of the FEC type in the FEC decoding unit based on the determination of the signal state determination unit;
A transmission unit that transmits a signal according to the changed FEC type in conjunction with the change of the setting of the FEC type by the FEC setting unit.
Transmitter / receiver. The signal state determination unit determines that the FEC type matches when the second number of bit errors is 0, and determines that the FEC type does not match when greater than 0.
The transmission / reception apparatus according to claim 4. The signal state determination unit determines that a failure in the network occurs when the bit error rate is equal to or greater than the predetermined threshold;
The transmission / reception apparatus according to claim 4 or 5. A reception method in OTN,
Receiving the transmitted signal and detecting the frame synchronously;
Performing FEC decoding processing on the synchronously detected frame and outputting an OTU frame;
Detecting a first bit error number of FAS in the detected OTU frame;
Detecting a second bit error number of FAS in the error-corrected OTU frame;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, Determining whether the FEC type matches based on the number of bit errors of 2, and causing the computer to execute a process. A transmission / reception method in OTN,
Receiving the transmitted signal and detecting the frame synchronously;
Performing FEC decoding processing on the synchronously detected frame and outputting an OTU frame;
Detecting a first bit error number of FAS in the detected OTU frame;
Detecting a second bit error number of FAS in the error-corrected OTU frame;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, Determining a match of the FEC type based on the number of bit errors of 2,
Changing the setting of the FEC type based on the determination;
And a step of transmitting a signal according to the changed FEC type in conjunction with a change in the setting of the FEC type. A receiving device connected to a network or circuit,
A synchronization detection unit that receives an FEC-encoded signal and detects a frame or codeword based on a fixed pattern for synchronization;
An FEC decoding unit that performs FEC decoding on the synchronously detected frame or codeword and outputs the frame or codeword;
A first synchronization pattern error detection unit that detects a first bit error number of a fixed pattern for synchronization in the frame or the codeword detected by the synchronization detection unit;
A second synchronization pattern error detection unit that detects a second number of bit errors of the fixed pattern for synchronization in the frame or the codeword that has been error-corrected by the FEC decoding unit;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, A signal state determination unit that determines FEC type match based on the number of bit errors of 2.
Receiver device. A receiving method of a receiving device connected to a network or a circuit,
Receiving an FEC-encoded signal and detecting a frame or codeword synchronously based on a fixed pattern for synchronization;
Performing FEC decoding on the synchronously detected frame or codeword and outputting the frame or codeword;
Detecting a first number of bit errors in a fixed pattern for synchronization in the detected frame or codeword;
Detecting a second number of bit errors in a fixed pattern for synchronization within the error-corrected frame or codeword;
It is determined whether the bit error rate calculated based on the first number of bit errors exceeds a bit error rate correctable by FEC, and if the bit error rate is smaller than a predetermined threshold, Determining whether the FEC type matches based on the number of bit errors of 2, and causing the computer to execute a process.

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