JP5678735B2 - COMMUNICATION SYSTEM, COMMUNICATION DEVICE, AND COMMUNICATION CONTROL METHOD - Google Patents

Description

  The present invention relates to a communication system that performs a compensation operation to transmit and receive signals, a communication device that can be applied to the communication system, and a communication control method.

  There is a communication system that performs communication by compensating a signal to be transmitted according to a state of a transmission path between communication apparatuses. For example, in a communication system using an optical fiber, signal waveform distortion due to chromatic dispersion of the optical fiber occurs. For efficient communication, dispersion compensation is performed so as to cancel this signal waveform distortion. There is a need. In the following, for convenience of explanation, an explanation will be given taking an optical communication system as an example. As one of dispersion compensation methods in an optical communication system, there is a method of performing variable dispersion compensation in an optical transmission device at a transmission end of a transmission line (see, for example, Patent Document 1).

  Chromatic dispersion is a physical quantity that varies in proportion to the length of the optical fiber. In particular, in recent high-speed optical fiber communication systems of 40 Gb / s or more, even a slight change in dispersion due to fiber breakage or the like easily distorts the waveform and degrades communication quality. For this reason, when the length of the optical fiber through which the optical path passes changes due to detouring of the optical fiber transmission line due to construction at the installation site or repair of the failure of the optical fiber transmission line, the dispersion compensation amount is adjusted to the optimum value. There is a need to.

JP 2010-34830 A (FIG. 1)

  For example, in the conventional chromatic dispersion compensation control method of an optical transmission device that performs chromatic dispersion compensation at the transmission end of an optical fiber transmission line, an operator instructs the optical transmission device to start adjustment via an out-of-band network. In addition, there is a problem that the adjustment cannot be controlled when communication between the out-of-band network and the optical transmission apparatus is disconnected or when an out-of-band network is not installed. Here, the out-of-band network is a network prepared exclusively for management, and usually an operator manages failure of each communication device using this network. In addition, in a WDM (Wavelength Division Multiplexing) system, an operator performs an operation in units of optical paths, and therefore, when a large number of optical paths pass through one transmission path, a load is imposed on the operator. When the operator makes an operation mistake and instructs the optical path under operation to perform adjustment, the signal quality of the path under operation may be affected.

  The present invention has been made to solve the above problems, and when it is necessary to adjust the compensation amount in the signal compensation operation, a management network such as an out-of-band network is not used, An object of the present invention is to provide means for controlling adjustment between communication devices.

A communication system according to the present invention includes a first communication device and a second communication device that are connected to each other via first and second transmission paths, and the first communication apparatus includes a second transmission path. The second communication device receives a signal from the first communication device via the first transmission path and receives a predetermined compensation value via the first transmission path. in configured communication system to a compensation operation to transmit a signal to the first communication device I line using the first communications device, an input interruption of a second signal from the communication device to the first communication device An input disconnection detecting means for detecting the input disconnection, and when the input disconnection detecting means detects the input disconnection, a notification that the input disconnection is detected (hereinafter referred to as a first notification) is sent to the second communication device. A first notification transmission means for transmitting the first notification, and the second communication device sends the first notification to the first notification When received via the transmission path, notification of the reception of the first notice (hereinafter referred to as second notification) to the second notification sending means for notifying the first communication apparatus, Ru provided with At the same time, when the first notification is received via the first transmission path, the compensation value is adjusted, the compensation operation using the adjusted compensation value is performed, and a signal is transmitted to the first communication device. first notice transmitting means transmits the first communication device a second notification until it receives via a second transmission path, a first notification to the second communication device.

The communication device according to the present invention includes an input disconnection detecting unit that detects an input disconnection of a signal from the opposing communication device connected via the first and second transmission lines, and an input disconnection detecting unit that disconnects the input. when it is detected, the notification relates to the detection of input interruption (hereinafter, the first notification) and a first notice transmitting means for transmitting to the second communication device through the first channel, facing communication Receiving means for receiving a signal transmitted by performing a compensation operation using the compensated compensation value adjusted by the opposing communication device when the device receives the first notification ; The first notification transmission means is a notification related to reception of the first notification to be transmitted when the opposite communication apparatus receives the first notification via the first transmission path (hereinafter referred to as a second notification). Until the first notification is received via the second transmission path

The communication control method according to the present invention includes a first communication device and a second communication device that are connected to each other via the first and second transmission paths, and the first communication device includes the second communication device A signal from the second communication device is received via the transmission line, and the second communication device receives the signal from the first communication device via the first transmission line and has a predetermined compensation. in the produced applicable communication control method in a communication system as a compensation operation to transmit a signal to the first communication device I rows using values, signals from the second communication device to the first communication device When a signal disconnection is detected in the input disconnection detection step and the input disconnection detection step, a notification that the input disconnection has been detected (hereinafter referred to as a first notification) A first notification transmission step for transmitting to the communication device; A second notification transmission step of transmitting, to the first communication device, a notification that the first notification has been received (hereinafter referred to as a second notification) when the communication device has received the first transmission path; When the second communication apparatus receives the first notification through the first transmission path, the compensation value is adjusted, and the compensation operation using the compensated compensation value is performed to perform the first communication. A signal transmission step of transmitting a signal to the device, wherein the first notification is transmitted to the second notification device until the second notification is received via the second transmission path in the first notification transmission step. Is executed.

  According to the present invention, when it is necessary to adjust the compensation amount in the signal compensation operation, the compensation amount adjustment can be controlled using the network used for communication between the communication apparatuses.

It is a block diagram of the communication system which concerns on Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the transponder shown in Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the transponder shown in Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the transponder shown in Embodiment 1 of this invention. It is a block diagram of the signal frame used in the communication system shown in Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the transponder shown in Embodiment 1 of this invention. It is a block diagram which shows the order of the cutting / restoring of the transmission line shown in Embodiment 1 of this invention. It is a block diagram which shows the order of the cutting / restoring of the transmission line shown in Embodiment 1 of this invention. It is a block diagram which shows the order of the cutting / restoring of the transmission line shown in Embodiment 1 of this invention. It is a block diagram of the communication system which concerns on Embodiment 2 of this invention. It is a block diagram of the signal frame used in the communication system shown in Embodiment 2 of this invention. It is a flowchart which shows operation | movement of the transponder shown in Embodiment 2 of this invention. It is a flowchart which shows operation | movement of the transponder shown in Embodiment 2 of this invention. It is a flowchart which shows operation | movement of the transponder shown in Embodiment 2 of this invention. It is a flowchart which shows operation | movement of the transponder shown in Embodiment 2 of this invention.

Embodiment 1 FIG.
A communication system to which the present invention is applied will be described using an optical communication system as an example. FIG. 1 shows a configuration diagram of a communication system according to Embodiment 1 of the present invention. Here, a case where two communication apparatuses (nodes) are connected to each other by two optical transmission lines will be described. Of course, the present invention can also be applied when three or more nodes are connected. Although omitted in FIG. 1, terminals and the like are connected to each node, and communication between terminals connected to different nodes is performed via each node and an optical transmission line. In FIG. 1, the node 1a has n transponders 111a, 112a,. . . 11na, a multiplexing unit 12a, a demultiplexing unit 13a, and amplifying units 14a and 15a. The transponder 111a transmits an optical signal to the other transponder 111b via a transmission path 16a having its own node as a transmission end. The optical signal is received from the other transponder 111b through the transmission line 16b whose own node is the receiving end. The transponder 111a includes a transmission function unit 1111a and a reception function unit 1112a, and the transmission function unit 1111a includes a dispersion compensation function unit 11111a.

  The transmission function unit 1111a converts the data signal (electrical signal) received from the terminal connected to the node 1a into an optical signal and outputs the optical signal. Based on this optical signal, the dispersion compensation function unit 11111a stores the variable signal stored therein. Dispersion compensation, that is, a signal having a waveform that cancels chromatic dispersion that occurs in the transmission line 16a is formed. The reception function unit 1112a converts an optical signal received via the transmission line 16b into an electrical signal. Also, the presence or absence of optical input from the transmission line 16b is determined, and the input interruption of the signal transmitted from the node 1b is detected. The configuration of the transponders 112a to 11na is the same as that of the transponder 111a, and a description thereof will be omitted.

  The multiplexing unit 12a combines the signals output from the transponders 111a to 11na to generate an optical multiplexed signal, and outputs the optical multiplexed signal to the amplification unit 14a. The demultiplexing unit 13a demultiplexes the optical multiplexed signal received from the amplification unit 15a and outputs the demultiplexed signals to the transponders 111a to 11na, respectively. The amplifying unit 14a amplifies the optical multiplexed signal input from the multiplexing unit 12a and outputs the amplified signal to the transmission line 16a. The amplifying unit 15a amplifies the optical multiplexed signal input from the transmission line 16b and outputs the amplified signal to the demultiplexing unit 13a. To do. The node 1b has the same configuration.

  The transmission line 16a transmits an optical multiplexed signal in the direction of the node 1b from the node 1a, and the transmission line 16b transmits an optical multiplexed signal in the direction of the node 1a from the node 1b. The transmission paths 16a and 16b are optical transmission paths, and are constituted by optical fibers, for example. Although a case where the nodes 1a and 1b are connected using two different transmission paths is shown here, a configuration may be adopted in which bidirectional communication is shared using one optical fiber.

Next, the operation will be described.
First, normal communication operation will be described. When data to be transmitted is generated in a terminal (not shown in FIG. 1) connected to the node 1a, the node 1a receives a data signal that is an electrical signal from the terminal in which the data is generated. In the node 1a, the transmission function unit 1111a in the transponder 111a converts the received electrical signal into an optical signal, and outputs the optical signal to the dispersion compensation function unit 11111a. The dispersion compensation function unit 11111a performs dispersion compensation based on the dispersion compensation value stored therein and outputs the result to the multiplexing unit 12a. The output optical signal is multiplexed together with optical signals from other transponders in the multiplexing unit 12a, amplified in the amplifying unit 14a, and then transmitted to the node 1b through the transmission line 16a. Upon receiving the optical signal from the node 1a, the node 1b amplifies the optical signal in the amplifying unit 15b, demultiplexes it in the demultiplexing unit 13b, and outputs it to the transponder 111b. The transmission function unit 1111b converts the optical signal into an electric signal. And transferred to the terminal (not shown in FIG. 1) described in the destination of the data signal. Note that, here, a configuration for performing dispersion compensation on an optical signal is shown, but dispersion compensation is performed on an electrical signal before conversion to an optical signal, and the electrical signal subjected to dispersion compensation is converted into an optical signal. It may be.

  When the optical transmission line length between communication devices changes due to optical fiber breakage or the like, it is necessary to adjust the dispersion compensation amount to an optimum value. In the communication system according to Embodiment 1 of the present invention, the dispersion compensation value is controlled to be autonomously adjusted between the communication devices. Hereinafter, the dispersion compensation control operation will be described.

  First, the overall operation of dispersion compensation control will be described with reference to FIGS. Here, it is assumed that communication is performed between the transponder 111a and the transponder 111b among the transponders of each node, and the operation is divided between the transponder 111a and the transponder 111b, and will be described with reference to FIGS. 3 and 2, respectively. In the following description, it is assumed that the dispersion compensation value is adjusted in the node 1a by exchanging the optical fiber of the transmission line 16a used for the communication from the node 1a to the node 1b.

  When the transponder 111b starts communication with the transponder 111a, the transponder 111b periodically transmits a signal to the transponder 111a, and periodically receives a signal from the transponder 111a (step S21). The transponder 111b monitors communication with the transponder 111a, and detects that adjustment of the opposite node 1a is necessary when the reception function unit 1111b detects an optical signal input interruption (step S22). When it is detected that the adjustment is necessary, the opposite transponder 111a is notified that the input interruption of the optical signal has occurred in the transponder 111b, that is, the adjustment of the dispersion compensation value is necessary (step S23). The transponder 111a that is notified that the adjustment is necessary transmits a notification that the adjustment is necessary to the transponder 111b. At this time, when the optical transmission line 16a is restored, this notification is sent to the transponder 111b, but not when it is not restored. When the transponder 111b receives a notification that the optical transmission line 16a is restored and needs to be adjusted, it returns to the normal communication state, but if it has not been received, the transponder 111a needs to be adjusted. This is continuously notified (step S24).

  On the other hand, when the transponder 111a starts communication with the transponder 111b, the transponder 111b periodically transmits a signal to the transponder 111b, and periodically receives the signal from the transponder 111b (step S21). When a notification indicating that adjustment by the transponder 111a is necessary is received from the transponder 111b (step S32), it is detected whether or not the optical transmission line 16a is restored. Then, the dispersion compensation value is adjusted (step S33). After the adjustment, the transponder 111a is notified that the notification that the adjustment is necessary is received from the transponder 111b, that is, the fact that the adjustment is necessary (step S34). Here, the configuration is such that the dispersion compensation value is adjusted before sending the notification. However, the present invention is not limited to this, and the configuration may be such that the dispersion compensation value is adjusted after this notification is sent.

  Hereinafter, operations corresponding to the steps described in FIGS. 2 and 3 will be described in detail. Here, a case where an optical fiber is allocated to the transmission line 16a, that is, a case where it is necessary to adjust the dispersion compensation value in the communication in the node 1a → node 1b direction will be described.

  First, an operation (step S22 in FIG. 2) for detecting that it is necessary to adjust the dispersion compensation value of the opposite transponder will be described by taking the operation of the transponder 111b as an example. Here, by detecting the occurrence of optical input interruption in the receiving transponder, it is detected that the dispersion compensation value of the opposite transponder (transmission transponder) needs to be adjusted. The detection that the dispersion compensation value of the opposing transponder needs to be adjusted is performed by detecting an Och-dLOS-P alarm defined in, for example, OTN (Optical Transport Network). The Och-dLOS-P alarm is an alarm generated by a transponder that detects an optical signal input interruption of its own device. When an optical fiber is broken in the transmission line 16a, the transmission line 16a is disconnected at one end, and an Och-dLOS-P alarm is generated in the transponder 111b. It can be determined that the transponder 111b is in a light input interruption state while the Och-dLOS-P alarm is generated, and is in a state where there is a light input while the Och-dLOS-P alarm is not generated.

  When the optical fiber cutting operation is completed, the reception function unit 1112b detects the recovery of the optical input. In this case, since the transmission line length of the transmission line 16a changes, the transponder 1111a at the transmission end of the transmission line 16a needs to adjust the dispersion compensation value of the dispersion compensation function unit 11111a. Therefore, when the optical input interruption occurs in the reception function unit 1112b and the Och-dLOS-P alarm occurs, the transponder 111b determines that the dispersion compensation function unit 11111a of the opposing transponder 111a needs to be adjusted. Note that the method for detecting the necessity of adjusting the dispersion compensation value of the opposing transponder is not limited to the method described above.

  Next, the operation (step S23 in FIG. 2) for notifying the opposing transponder that the dispersion compensation value needs to be adjusted will be described with reference to FIG. 4 by taking the operation of the transponder 111b as an example. Here, description will be made assuming that notification is performed using the signal frame 3 shown in FIG. The signal frame 3 shown in FIG. 5 is composed of a main signal area 30 and a control signal area 31. The main signal area 30 is an area for storing information on communication contents, and the control signal area 31 is a signal used for transport control. The stored area, the adjustment necessary information area 311 is an area indicating whether the adjustment of the dispersion compensation value of the dispersion compensation function unit 11111b of the opposing transponder 111b is “necessary” or “unnecessary”, and the adjustment necessary recognition information area 312 is the transponder 111a. An area for notifying the opposite transponder 111b whether or not it is necessary to adjust the dispersion compensation function unit 11111a, and the other control information area 313 are indicated by an adjustment necessary information area 311 and an adjustment necessary recognition information area 312. This is an area indicating control information other than information. Here, the description content of each area is represented by “”, and for example, the adjustment necessary information area 311 is represented as “necessary”.

  If the transponder 111b is in a normal communication state, the adjustment required information area 311 of the signal frame 3 is set to “unnecessary” and this signal is transmitted to the transponder 111a (step S41). Further, the transponder 111b monitors the communication state with the transponder 111a, and detects a light input interruption at the reception function unit 1112b (step S42). When the transmission line 16a is disconnected due to the optical fiber breakage, the reception function unit 1112b detects the light input interruption, and the transponder 111b sets the adjustment necessary information area 311 of the signal frame 3 to be transmitted to “necessary” (step S43). ), This signal frame is transmitted to the opposite transponder 111a via the transmission line 16b. Also, it is determined whether or not the optical input at the reception function unit 1112b has been recovered (step S44).

  When the optical input is recovered, the transponder 111b determines whether or not the adjustment necessary recognition information area 312 of the signal frame 3 received from the transponder 111a is “recognition” (step S45). In the transponder 111b, the adjustment necessary information area 311 of the transmission signal frame 3 is set to “necessary” until the adjustment necessary recognition information area 312 of the signal frame 3 received from the transponder 111a becomes “recognition” as described later. The signal is continuously transmitted to the transponder 111a. Only when the adjustment necessary recognition information area 312 becomes “recognition”, the normal communication state is set, and the adjustment necessary information area 311 of the transmission signal frame 3 is set to “unnecessary”. As described above, the transponder 111b is configured to continue to notify the transponder 111a that adjustment is necessary until receiving a notification from the opposing transponder 111a that the adjustment is necessary. . It should be noted that whether the notification is intermittent or continuous, there is no substantial change in the present invention.

  The operation of notifying the opposing transponder that it is necessary to adjust the dispersion compensation value of its own transponder will be described with reference to FIG. 6, taking the operation of the transponder 111a as an example. During normal communication between the transponder 111a and the transponder 111b, the transponder 111a transmits a signal with the adjustment necessary recognition information area 312 of the signal frame 3 to be transmitted set to “not yet” (step S61), and the transponder 111a. It is determined whether the adjustment necessary information area 311 of the signal frame 3 received from “necessary” is “necessary” (step S62). If the adjustment necessary information area 311 is “necessary”, the transponder 111a sets the adjustment necessary recognition information area 312 of the signal frame 3 to be transmitted to “recognition” (step S63), and the adjustment necessary information area 311 of the received signal frame 3 is It is determined whether or not it is “unnecessary” (step S64). When the adjustment necessary information area 311 is “unnecessary”, the state shifts to a normal communication state, and the adjustment necessary recognition information area of the signal frame 3 to be transmitted is set to “not yet”. As described above, when the transponder 111a receives a notification from the transponder 111b that the dispersion compensation value needs to be adjusted, the transponder 111a notifies the transponder 111b that the content of the notification has been recognized.

  The adjustment operation (step S33 in FIG. 3) in the transponder 111a is performed as follows, for example. When the transponder 111a changes the dispersion compensation value of the dispersion compensation function unit 11111a, the opposite transponder 111b inserts the measurement result of the received signal quality in the reception function unit 1112b into the other control information area 313 of the signal frame 3 to transponder 111a. Notify The transponder 111a changes several dispersion compensation values of the dispersion compensation function unit 11111a and compares the signal quality at the reception function unit 1112b in each case to determine an optimum dispersion compensation value. Note that the method of adjusting the dispersion compensation value is not limited to the method described above.

  Since the communication system according to Embodiment 1 has the above-described configuration, adjustment is necessary when it is necessary to adjust the dispersion compensation value of the dispersion compensation function unit in the transmission end node of the transmission path. It is possible to start the adjustment autonomously using only the transmission path between the communication devices in the transponder of the transmitting end node, and even if the out-of-band network is not installed, the adjustment of the dispersion compensation value Can be controlled.

  Here, a configuration has been described in which the content to be notified is described in the control signal area of the signal frame and transmitted, but the notification method is not limited to this. For example, an optical output ON / OFF pattern corresponding to each notification content is determined in advance, the optical output of the own node is turned ON / OFF with the determined pattern, and the notification content is transmitted to the opposite node. Anyway. Accordingly, even when notification is performed in a state where the dispersion compensation value is not adjusted and the waveform is broken, it is possible to notify the opposite node.

  Also, OTN defines an alarm called OTU-aBDI that is sent back to a transmission node when an optical input interruption of a received signal occurs. However, the alarm is generated not only when the optical input is cut off at the receiving end, but also when the TTI (Trail Trace Indicator) value used for the connection test is set incorrectly. If this alarm is used to detect a light input interruption at, unnecessary adjustments may be made. As in the present invention, it is determined that the dispersion compensation function unit 11111a of the opposite transponder 111a needs to be adjusted by the light input interruption (Och-dLOS-P alarm) detected by the reception function unit 1112b, and the result is Since it is stored in the adjustment necessary information area 311 of the signal frame 3 and notified to the transponder 111a, the dispersion compensator 11111a performs adjustment when the transmission line 16a is disconnected, and can avoid unnecessary adjustment. .

  Here, an example in which an optical transmission line, in particular, an optical fiber cable is used as a transmission line used for communication between communication apparatuses has been described, but the present invention is not limited to this. For example, a coaxial line or the like is used. However, the same effect can be obtained.

In addition, the communication system according to Embodiment 1 can also provide the following effects.
When two communication devices (nodes 1a and 1b) are connected by two transmission lines 16a and 16b, the order of the disconnection and restoration of the transmission lines 16a and 16b is as follows: There are two possible patterns, and FIGS. 7 to 9 are block diagrams showing the order of cutting / restoring for each pattern. The node 1a and the node 1b are similar communication apparatuses. Here, a case where the transmission line 16a is disconnected first will be described. However, even if the transmission line 16b is disconnected, the transmission line is substantially transmitted. The description is omitted here, as is the case with 16a being cut first.
(A) Transmission line 16a is cut off → Transmission line 16a is restored (FIG. 7)
(A) Transmission path 16a is cut off → Transmission path 16b is cut off → Transmission path 16a is restored → Transmission path 16b is restored (FIG. 8)
(C) Transmission line 16a is cut off → Transmission line 16b is cut off → Transmission line 16b is restored → Transmission line 16a is restored (FIG. 9)
7 to 9, for convenience of explanation, only one transponder is shown in each node, and other transponders are omitted. 7 to 9, the disconnection / recovery of each transmission path and the generation of each node alarm are described in time series from top to bottom.

For each pattern, the operation when the dispersion compensation is controlled autonomously using the network used for communication without applying the communication system according to Embodiment 1 of the present invention will be described.
First, the case (a) shown in FIG. 7 will be described. In (a), the transmission line 16a is first disconnected, an Och-dLOS-P alarm is generated in the transponder (TPND) of the node 1b where the input of the optical signal is interrupted, and the transmission line 16a is disconnected via the transmission line 16b. Notify that it has occurred. As a result, an OTU-dBDI alarm is generated in the node 1a. Here, when the OTU-dBDI alarm detects an alarm such as Och-LOS-P at the receiving node (node 1b), it notifies the transmitting node that the alarm has occurred, and the transmission that received the notification This alarm is issued at the node. Thereby, the node 1a can recognize that the own node needs to adjust the dispersion compensation value. On the other hand, since no disconnection occurs in the optical transmission line 16b, it is not necessary to adjust the dispersion compensation value in the node 1b.

  The above case (A) shown in FIG. 8 will be described. In this case, first, the transmission line 16a is disconnected, and an Och-dLOS-P alarm is generated in the transponder of the node 1b as in the case of (a) above, and is transferred to the transmitting node and issued at the transmitting node ( OTU-dBDI) occurs, and it can be recognized that the dispersion compensation value of the own node needs to be adjusted.

  Next, when the transmission line 16b is disconnected, an Och-dLOS-P alarm is generated also in the node 1a. In this case, since the transmission line 16a is in a disconnected state, the node 1b cannot be notified that the Och-dLOS-P alarm has occurred. Next, since the transmission line 16a is restored and the Och-dLOS-P alarm is generated in the node 1a at this time, it is notified to the node 1b that the Och-dLOS-P alarm is generated from the transmission function unit of the node 1a. The node 1b can recognize that it is necessary to adjust the dispersion compensation value of the own node. Therefore, the node 1a and the node 1b can recognize that the own node needs to adjust the dispersion compensation value.

  The case of the above (c) shown in FIG. 9 will be described. In this case, as in the case of (A), the transmission line 16a is disconnected, and the node 1a can recognize that it is necessary to adjust the dispersion compensation value of its own node. In addition, when the transmission line 16b is disconnected and an Och-dLOS-P alarm is generated in the node 1a, in this case, since the transmission line 16a is in a disconnected state, it is confirmed that the Och-dLOS-P alarm has occurred. The node 1b cannot be notified. Next, the transmission line 16b is restored, and then the transmission line 16a is restored. In this case, since the transmission line 16b has been restored first, the Och-dLOS-P alarm is not generated in the node 1a when the transmission line 16a is restored, so the transmission line 16b is disconnected for the node 1b. This is not notified, and the node 1b actually has a disconnection. Therefore, it is necessary to adjust the dispersion compensation value in the node 1b, but the node 1b cannot recognize it. Accordingly, the node 1a can recognize that the dispersion compensation value of the own node needs to be adjusted, whereas the node 1b needs to adjust the dispersion compensation value of the own node. The problem of not being able to occur.

  In the communication system according to Embodiment 1 of the present invention, the transponder 111a recognizes the necessity for adjustment in the dispersion compensation function unit 11111a, and changes the adjustment necessity recognition information area 312 of the signal frame 3 to be transmitted to “recognition”. Since the transponder 111b continues to notify the transponder 111a that adjustment is necessary, even when the transmission line 16b is disconnected and restored during the disconnection of the transmission line 16a, as in the case of (c) in FIG. The transponder 111b can know that the dispersion compensation function unit 1111b needs to be adjusted. Therefore, the communication apparatus according to Embodiment 1 can notify and recognize that each node needs to adjust the dispersion compensation value even in the case of (c) shown in FIG. An effect is obtained that the dispersion compensation value adjustment can be controlled more appropriately.

Embodiment 2. FIG.
In the first embodiment, two nodes are connected, and the transmission function unit and the reception function unit of one transponder are connected to the transmission side and the reception side of the opposite optical fiber transmission lines. Mode 2 shows a case where three nodes are connected and the transmission function unit and the reception function unit of one transponder are connected to an optical fiber transmission line in the same direction.

  FIG. 10 shows a configuration diagram of a communication system according to the second embodiment. In FIG. 10, the nodes 1a and 1b are the same as those in FIG. The node 6 includes transponders 611a to 61na, 611b to 61nb, amplification units 62a, 62b, 66a, 66b, demultiplexing units 63a, 63b, multiplexing units 64a, 64b, communication paths 681a to 68na, 681b to 68nb. The amplifying unit 62a amplifies the optical multiplexed signal input from the transmission line 66a and outputs the amplified signal to the demultiplexing unit 63a. The demultiplexing unit 63a demultiplexes the optical multiplexed signal input from the amplification unit 62a and inputs the demultiplexed signal to the transponders 611a to 61na. The same applies to the amplifying unit 62b and the demultiplexing unit 63b. The node 6 relays a signal transmitted from the node 1a to the node 1b, and is hereinafter referred to as a relay node as appropriate.

  The transponder 611a converts the optical signal received from the demultiplexing unit 63a into an electrical signal, regenerates the electrical signal by 3R (Re-amplification: amplification, Re-timing: timing recovery, Re-shaping: waveform shaping), and then the optical signal again. And output to the multiplexing unit 64a. In other words, the reception function unit 6112a converts the optical signal input from the demultiplexing unit 63a into an electrical signal, performs 3R reproduction, and then transmits it to the transmission function unit 6111a. Further, the presence / absence of light input from the transmission path 66a via the amplification section 62a and the demultiplexing section 63a is determined, and the control signal 71 is transmitted to the transmission function section 6111b of the transponder 611b via the communication path 681a. The transmission function unit 6111a converts the electrical signal received from the reception function unit 6112a into an optical signal and outputs the optical signal to the multiplexing unit 64a. The dispersion compensation function unit 61111a stores a variable dispersion compensation value, and generates a signal that cancels chromatic dispersion occurring in the transmission path 67a based on the dispersion compensation value. The communication path 681a is used when the reception function unit 6112a control signal 71 of the transponder 611a is transmitted to the transmission function unit 6111b of the transponder 611b. The same applies to the other transponders 612a to 61na and 611b to 61nb.

  In the configuration shown in FIG. 10, the transponder 611a and the transponder 611b stored in the relay node and facing the communication direction are referred to as “pair” transponders. The same applies to the transponders 612a to 61na and 612b to 61nb.

  The multiplexing unit 64a outputs an optical multiplexed signal obtained by multiplexing the optical signals input from the transponders 611a to 61na to the amplifying unit 66a, and the amplifying unit 65a amplifies the optical multiplexed signal input from the multiplexing unit 64a. The same applies to the multiplexing unit 64b and the amplification unit 65b. The transmission path 66a transmits an optical signal from the transponder 111a to the transponder 611a, and the transmission path 67a transmits an optical signal from the transponder 611a to the transponder 111b. Similarly, the transmission path 66b transmits an optical signal from the transponder 111b to the transponder 611a, and the transmission path 6ba transmits an optical signal from the transponder 611a to the transponder 111a.

  FIG. 11 shows a control signal frame format used when the reception function unit 6112a of the transponder 611a transmits the control signal 31 received from the transponder 111a and the optical input interruption information detected by the reception function unit 6112a to the transponder 611b. Similarly, the reception function unit 6112b of the transponder 611b uses the control signal frame format to transfer the control signal 31 received from the transponder 111b and the optical input interruption information detected by the reception function unit 6112b to the transponder 611a. The transponders 612a to 61na and 611b to 61nb also exchange information with a pair of transponders using the same control signal 71.

  In FIG. 11, a control signal 71 is a signal used for transport control. The adjustment necessary information area 711 is an area indicating whether the dispersion compensation value adjustment of the dispersion compensation function unit 61111b of the transfer destination transponder 611b is “necessary” or “unnecessary”, and the adjustment necessary recognition information area 712 is an area where the opposite transponder 111a The dispersion compensation function unit 11111a is notified that the dispersion compensation value needs to be adjusted, and an area for notifying whether or not the dispersion compensation value is recognized. The light input break detection information area 713 is a reception function unit of the transponder 611a. In 6112a, an area indicating whether or not a light input interruption is detected, the other control information area 714 is an area indicating control information other than the information indicated by the adjustment necessary information area 711 and the adjustment necessity recognition information area 721.

The operation will be described.
First, normal communication operation will be described. Data to be transmitted is generated in a terminal (not shown in FIG. 10) connected to the node 1a, and the node 1a receives a data signal that is an electrical signal from the terminal in which the data is generated. In the node 1a, the transmission function unit 1111a in the transponder 111a converts the received electrical signal into an optical signal, and outputs the optical signal to the dispersion compensation function unit 11111a. The dispersion compensation function unit 11111a performs dispersion compensation based on the dispersion compensation value stored therein and outputs the result to the multiplexing unit 12a. The output optical signal is multiplexed together with optical signals from other transponders in the multiplexing unit 12a, amplified in the amplifying unit 14a, and then transmitted to the node 6 through the transmission path 66a. Note that, here, a configuration for performing dispersion compensation on an optical signal is shown, but dispersion compensation is performed on an electrical signal before conversion to an optical signal, and the electrical signal subjected to dispersion compensation is converted into an optical signal. It may be.

  The node 6 that has received the optical signal from the node 1a amplifies the optical signal in the amplifying unit 62a, demultiplexes it in the demultiplexing unit 63a, and then outputs it to the transponder 611a. The reception function unit 6111a in the transponder 611a performs conversion into an electrical signal and 3R reproduction, and the transmission function unit 6111a converts the signal again into an optical signal. Then, the dispersion compensation function unit 61111a performs dispersion compensation processing. It is output to the wave section 64a. The output optical signal is multiplexed together with optical signals from other transponders in the multiplexing unit 64b, amplified in the amplifying unit 14a, and then transmitted to the node 1b via the transmission path 67a. Upon receiving the optical signal from the node 1a, the node 1b amplifies the optical signal in the amplifying unit 15b, demultiplexes it in the demultiplexing unit 13b, and then outputs it to the transponder 111b. The transmission function unit 1111b converts the optical signal into an electrical signal. Then, it is transferred to the terminal (not shown in FIG. 10) described in the destination of the data signal.

  Next, the overall operation of dispersion compensation control will be described. Here, a description will be given separately for a case where an optical fiber is allocated to the transmission path 66a and a case where an optical fiber is allocated to the transmission path 67a.

First, a case where an optical fiber is broken in the transmission line 66a will be described. In this case, the operation of the transponder 111a of the node 1a is the same as that shown in the first embodiment and is as shown in FIG. The node 6 performs the same operation as the node 1b shown in the first embodiment as shown in FIG.
Hereinafter, operations corresponding to the steps described in FIGS. 3 and 2 in the communication system according to Embodiment 2 will be described in detail.

  The operation for detecting that the dispersion compensation value of the opposing transponder needs to be adjusted will be described by taking the operation of the transponder 611a as an example. When an optical fiber is broken in the transmission line 66a, the transmission line 66a is cut. At this time, the optical input interruption is detected in the reception function unit 6112a, and an Och-dLOS-P alarm is generated in the transponder 611a. When the optical fiber splitting operation is completed, the optical input in the reception function unit 6112a is restored, and the Och-dLOS-P alarm is not generated. In this case, since the transmission path length of the transmission path 66a changes, the transponder 111a at the transmission end of the transmission path 66a needs to adjust the dispersion compensation value of the dispersion compensation function unit 11111a. Therefore, the transponder 611a needs to adjust the dispersion compensation function unit 11111a of the transponder 111a when the optical input interruption occurs in the reception function unit 6112a and the Och-dLOS-P alarm is generated, as in the case of the first embodiment. It is judged that. When it is determined that adjustment is necessary, the light input break detection information area 713 is set to “occurrence”, and the control signal 71 is transmitted to the transponder 611b.

  Next, the operation of notifying the opposing transponder that the adjustment of the dispersion compensation value is necessary will be described with reference to FIG. 12 by taking the operation of the transponder 611b as an example. In a normal communication state, the transponder 611b sets the adjustment necessary information area 311 to “unnecessary” and transmits the signal frame 3 to the transponder 111a (step S121). Further, it is determined whether or not the light input break detection information area 713 of the control signal 71 received from the reception function unit 6112a of the transponder 611a is “occurrence” (step S122). When the reception function unit 6112a detects a light input break and the light input break detection information area 713 of the control signal 71 is “occurrence”, the transponder 611b sets the adjustment necessary information area 311 to “necessary” Frame 3 is transmitted to the transponder 111a (step S123).

  The transponder 611b determines whether or not the adjustment necessity recognition information area 712 of the control signal 71 received from the reception function unit 6112a of the transponder 611a is “recognition” (step S124). When the transponder 611a does not receive the notification that the dispersion compensation value adjustment is necessary from the transponder 111a as will be described later, and the adjustment necessity recognition information area 712 is “not yet”, the transponder 611b With the adjustment necessary information area 311 set to “necessary”, the signal frame 3 is continuously transmitted to the transponder 111a. When the adjustment necessary recognition information area 712 becomes “recognition”, the state shifts to a normal communication state. As described above, when the transponder 611b receives a notification from the transponder 111a that the adjustment of the dispersion compensation value is necessary, the transponder 611b notifies the transponder 111a that the content of the notification has been recognized.

  The operation and adjustment operation for notifying that the transponder 111a recognizes that it is necessary to adjust the dispersion compensation value of its own transponder are the same as those in the first embodiment and will not be described.

Next, a case where an optical fiber is broken in the transmission path 67a will be described. In this case, the operation of the transponder 111b of the node 1b is the same as that of the node 1b shown in the first embodiment and is as shown in FIG. The node 6 performs the same operation as the node 1a shown in the first embodiment, as shown in FIG.
The operations corresponding to the steps described in FIGS. 2 and 3 in the communication system according to Embodiment 2 will be described in detail below.

  The operation of the transponder 111b detecting that the dispersion compensation value of the opposite transponder (transponder 611b) needs to be adjusted and the operation of notifying the transponder 611b that the dispersion compensation value needs to be adjusted are as follows. It is the same as that of form 1, and description is abbreviate | omitted.

  With reference to FIG. 13, the operation of notifying that the transponder in a pair recognizes that the dispersion compensation value adjustment is necessary will be described with reference to FIG. 13 as an example of the operation of the transponder 611a. In a normal communication state, the transmission function unit 6111a of the transponder 611a sets the adjustment necessary recognition information area 312 to “not yet” and transmits the signal frame 3 to the transponder 111b (step S131). Further, it is determined whether or not the adjustment necessary information area 711 of the control signal 71 received from the reception function unit 6112b is “necessary” (step S132). When it is notified from the transponder 111b that the dispersion compensation value of the own node needs to be adjusted and the adjustment necessary information area 711 is “necessary”, the transmission function unit 6111a of the transponder 611a is stored inside After adjusting the dispersion compensation value, the adjustment necessary recognition information area 312 is set to “recognition”, the signal frame 3 is transmitted (step S133), and the adjustment necessary information area of the control signal 71 received from the reception function unit 6112b of the transponder 611b. When 711 becomes “unnecessary”, the state shifts to a normal communication state (step S134).

  The adjustment operation in the transponder 611a is the same as that of the transponder 111a shown in the first embodiment, and a description thereof will be omitted.

  The communication system according to the second embodiment is different from the communication system according to the first embodiment in that control signals are exchanged between paired transponders in the node 6. Here, regarding the exchange of this control signal, the operation of the transponder 611a is the operation of transferring the information of the adjustment necessary information area 311 and the adjustment necessity recognition information area 312 of the signal frame 3 received from the opposite transponder to the pair of transponders. An example will be described with reference to FIG.

  In a normal communication state, the reception function unit 6112a of the transponder 611a sets the adjustment necessary information area 711 to “unnecessary” (step S141), sets the adjustment necessary recognition information area 712 to “not yet”, and sends a control signal 71 to the transponder 611b. Is transmitted (step S142). Also, the reception function unit 6112a of the transponder 611a determines whether or not the adjustment necessary information area 311 of the received signal frame 3 is “necessary” (step S143), and if it is “unnecessary”, the reception function unit 6112a of the transponder 611a. Makes the adjustment necessary information area 711 of the control signal 71 to be transmitted “unnecessary” (step S144). When the adjustment necessary information area 311 is “necessary”, the reception function unit 6112a of the transponder 611a sets the adjustment necessary information area 711 of the control signal 71 to be transmitted to “necessary” (step S145).

  The reception function unit 6112a of the transponder 611a determines whether or not the adjustment necessary recognition information town area 312 of the received signal frame 3 is “recognition” (step S146), and if “not”, the reception function unit 6112a of the transponder 611a. Makes the adjustment necessary recognition information town area 712 of the control signal 71 to be transmitted "not yet" (step S147). If the adjustment necessary recognition information town area 312 is “recognition”, the reception function unit 6112a of the transponder 611a sets the adjustment necessity recognition information area 711 of the control signal 71 to be transmitted to “recognition” (step S148).

  Further, the change process of the light input break detection information area 713 of the control signal 71 to be transmitted will be described with reference to FIG. 15 taking the operation of the transponder 611a as an example.

In a normal communication state, the reception function unit 6112a of the transponder 611a sets the optical input break detection information area 713 of the control signal 71 to be transmitted to “not yet” (step S151). The reception function unit 6112a of the transponder 611a determines whether or not an optical input interruption for reception has occurred (step S152). If an optical input interruption has occurred, the reception function unit 6112a of the transponder 611a transmits the control signal 71 to be transmitted. The light input break detection information area 713 is set to “detection” (step S153). In addition, the reception function unit 6112a of the transponder 611a determines whether or not the received optical input has been recovered (step S154), and if it has recovered, shifts to a normal communication state.
The transponders 612a to 61na and 611b to 61nb operate similarly.

  Although the description has been given of the case where the opposing transponder of the transponders 611a and 611b is the transponder 1a or the transponder 1b, the present system can be applied even when the opposing transponder is a transponder having the same configuration as the transponder 611a.

  Since the communication system according to the second embodiment has the above-described configuration, the compensation amount adjustment is controlled using only the network used for communication between the communication devices, as in the first embodiment. be able to. Further, by exchanging control signals between pairs of transponders in the relay node, it is possible to appropriately control compensation amount adjustment even when communication is performed via the relay node.

1a, 1b node, 3 signal frame, 6 node, 12a, 12b multiplexing unit, 13a, 13b demultiplexing unit, 14a, 14b amplifying unit, 15a, 15b amplifying unit, 16a, 16b transmission path, 30 main signal region, 31 Control signal area, 62a, 62b multiplexing unit, 63a, 63b demultiplexing unit, 64a, 64b amplifying unit, 65a, 65b amplifying unit, 66a, 66b transmission path, 67a, 67b transmission path, 681a-68na, 681b-68nb communication 311 Adjustment required information area, 312 Adjustment required recognition information area, 313 Other control information area, 111a to 11na, 111b to 11nb Transponder, 1111a to 11n1a, 1111b to 11n1b Functional part, 11111a-11n 11a, 11111b to 11n11b Dispersion compensation function unit, 611a to 61na, 611b to 61nb Transponder, 6111a to 61n1a, 6111b to 61n1b Transmission function unit, 6112a to 61n2a, 6111b to 61n2b Reception function unit, 61111a to 61n11a, 61111b to 61n11b Functional part

Claims (9)

A first communication device and a second communication device connected to each other via a first and a second transmission path, wherein the first communication device includes the second communication path via the second transmission path; The signal from the communication device is received, and the second communication device receives the signal from the first communication device via the first transmission path and uses a predetermined compensation value. in configured communication system to transmit a signal to the compensation operation to the I row first communication device,
The first communication device is:
An input interruption detecting means for detecting an input interruption of a signal from the second communication device to the first communication device;
A first notification that transmits a notification that the input disconnection has been detected (hereinafter referred to as a first notification) to the second communication device when an input disconnection is detected by the input disconnection detection means; Notification sending means;
With
The second communication device is:
When the first notification is received via the first transmission path, a notification that the first notification has been received (hereinafter referred to as a second notification) is notified to the first communication device. second notification transmission means comprises a Rutotomoni that, if the first notification was received via the first transmission path, to adjust the compensation value, using the compensation value was the adjustment Performing a compensation operation and transmitting a signal to the first communication device;
The first notification transmission unit transmits the first notification to the second communication device until the first communication device receives the second notification via the second transmission path. about,
A communication system characterized by the above. The second communication device is a communication system that performs dispersion compensation using a predetermined dispersion compensation value and transmits a signal to the first communication device ,
The first notification transmission means transmits a notification that the dispersion compensation value needs to be adjusted as the first notification ,
When the second communication device receives the first notification, the second communication device adjusts the dispersion compensation value, performs dispersion compensation using the adjusted dispersion compensation value, and sends a signal to the first communication device. Send
When the first communication device receives a signal transmitted by performing dispersion compensation using the adjusted dispersion compensation value, the first communication device notifies the second communication device of a quality measurement result related to the signal ;
The communication system according to claim 1. The second notification transmission means receives the first notification as the second notification, and transmits a notification indicating that the dispersion compensation value needs to be adjusted;
The communication system according to claim 2. The first notification transmitting means transmits the first notification intermittently or continuously;
The communication system according to any one of claims 1 to 3. The first notification transmission means transmits a signal frame having an adjustment necessary information area for notifying that adjustment of a dispersion compensation value of the second communication apparatus is necessary;
The communication system according to any one of claims 2 to 4. The second notification transmission means is notified that the second communication device is informed that the dispersion compensation value needs to be adjusted from the first opposite communication device, and has recognized that Transmitting a signal frame having an adjustment recognition information area to be notified to the communication device;
The communication system according to any one of claims 3 to 5. At least one of the first communication device and the second communication device includes a plurality of transponders,
Exchanging control signals between the plurality of transponders;
The communication system according to any one of claims 1 to 6. An input disconnection detecting means for detecting an input disconnection of a signal from the opposing communication device connected via the first and second transmission paths;
When an input disconnection is detected by the input disconnection detection means, a notification regarding the detection of the input disconnection (hereinafter referred to as a first notification) is sent to the second communication device via the first transmission path. First notification transmitting means for transmitting;
When the opposite communication device receives the first notification, the opposite communication device adjusts a compensation value, and receives a signal transmitted by performing a compensation operation using the adjusted compensation value. Means,
With
The first notification transmission unit is configured to notify the reception of the first notification to be transmitted when the opposite communication apparatus receives the first notification via the first transmission path (hereinafter referred to as a second notification). To transmit the first notification until it is received via the second transmission path,
A communication device characterized by the above. A first communication device and a second communication device connected to each other via a first and a second transmission path, wherein the first communication device includes the second communication path via the second transmission path; A signal from a communication device is received, and the second communication device receives a signal from the first communication device via the first transmission path and compensates using a predetermined compensation value. in applicable communication control method operating to a communications system configured to send a signal to the first communication device I lines,
An input disconnection detecting step of detecting an input disconnection of a signal from the second communication device to the first communication device;
A first notification for transmitting a notification that the input disconnection has been detected (hereinafter referred to as a first notification) to the second communication device when an input disconnection of the signal is detected in the input disconnection detecting step. Sending step;
When the second communication device receives the first notification via the first transmission path, a notification that the first notification has been received (hereinafter referred to as a second notification) A second notification transmission step for transmitting to one communication device;
When the second communication device receives the first notification via the first transmission path, the compensation value is adjusted, and a compensation operation using the compensated compensation value is performed. A signal transmission step of transmitting a signal to the first communication device;
With
Transmitting the first notification to the second notification device until the second notification is received via the second transmission path in the first notification transmission step;
A communication control method characterized by the above.

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