JPWO2008126220A1 - Optical signal transmission control device and optical signal transmission control method - Google Patents

Abstract

Regarding an optical signal transmission control device and an optical signal transmission control method, an abnormal optical signal is detected and transmission is stopped.
An optical signal transmission control device and an optical signal transmission control method in a PON system in which a plurality of subscriber line termination devices 1 are connected to an aggregated line termination device 3 via an optical coupler 2 and an optical transmission line, comprising: A PON processing unit 11 that processes the electrical signal, an optical transmission unit 17 that converts an electrical signal into an optical signal and transmits the optical signal, a transmission control unit 16 that inputs the electrical signal from the PON processing unit 11 to the optical transmission unit 17, and an optical abnormality An output monitoring unit 18, which monitors the optical signal from the light sending unit 17 to monitor the presence / absence of an abnormality in the optical signal, and outputs an abnormality detection signal at the time of abnormality detection to the PON Input to any one or more of the processing unit 11, the transmission control unit 16, and the light transmission unit 17 is performed to control transmission stop of the optical signal.

Description

  The present invention relates to an optical signal transmission control device and an optical signal transmission in a PON (Passive Optical Network) system including an collective line terminator (OLT) and a subscriber line terminator (ONU). It relates to a control method.

  In the PON system, a plurality of subscriber line terminators ONUs and optical couplers are connected by individual optical transmission lines, but the optical couplers to the collective line terminator OLT are connected by a common optical transmission line. The plurality of subscriber line termination units ONU are assigned optical signal transmission start timings and transmission duration times that do not overlap each other, and transmitted from the plurality of subscriber line termination units ONUs at different assigned transmission times in the optical coupler. The optical signals are time-multiplexed and transmitted to the collective line termination device OLT through one optical transmission line. The optical signal from the collective line termination unit OLT is branched by an optical coupler and transmitted simultaneously to a plurality of subscriber line termination units ONU. In such a PON system, even if one of a plurality of subscriber line terminators transmits an optical signal other than the allocated transmission time due to a failure or the like, the transmission optical signals of other subscriber line terminators and A collision occurs in the optical coupler, and the line is down due to a transmission error.

Therefore, the optical signal from each subscriber line terminator before being time-multiplexed by the optical coupler is transmitted to the aggregated line terminator OLT side through an optical transmission line different from that of the optical coupler side, and is provided in the aggregated line terminator. The device monitors the transmission optical signal of each subscriber line termination device, determines whether or not the optical signal is transmitted according to the allocated transmission time, and transmits the optical signal at a transmission time that deviates from the allocated transmission time. When a transmitting subscriber line terminating device is detected, the subscriber line terminating device is used as a failed subscriber line terminating device, and the optical signal sent to the optical coupler is blocked by the optical breaker provided in the preceding stage of the optical coupler. The structure which performs is proposed (for example, refer patent document 1).
JP-A-11-98078)

  Since the PON system requires only one optical transmission line between the collective line terminator OLT and the optical coupler, the system cost can be reduced compared to the point-to-point method. In the optical coupler, it is necessary to start the transmission of the optical signal at the assigned transmission start timing and finish the transmission within the assigned transmission duration so that the optical signals do not coincide with each other in time. When the optical signal transmission is started earlier than the allocation transmission start timing, or when the optical signal is continuously transmitted beyond the transmission continuation time, for example, it is transmitted from another subscriber line termination unit ONU. There was a problem that a collision occurred in the optical signal and the optical coupler, a transmission error occurred, and all the subscriber line terminators ONU under the aggregated line terminator OLT could not communicate, resulting in a system down state.

  With regard to such a problem, the above-mentioned Patent Document 1 provides a monitoring device in the collective line termination device OLT, branches an optical signal from each subscriber line termination device ONU before time multiplexing by an optical coupler, Transmission to the monitoring device via an optical transmission line separate from the transmission optical transmission line, enabling monitoring corresponding to the subscriber line termination device ONU, and blocking the optical signal from the abnormal subscriber line termination device ONU The configuration has a problem in that the advantage of using only one optical transmission line from the optical coupler to the collective line termination device OLT in the PON system is lost.

  The present invention monitors the normality in the subscriber line termination unit ONU without losing the advantages of the PON system, and when an abnormality occurs, the transmission of the optical signal is blocked, and other subscriber line termination units ONU An object is to prevent interference with optical signal transmission.

  An optical signal transmission control device according to the present invention is an optical signal transmission control device in a PON system in which a plurality of subscriber line termination devices are connected to an aggregate line termination device via an optical coupler and an optical transmission line. A PON processing unit for processing a signal, a light sending unit for converting an electric signal into an optical signal and transmitting the signal, a sending control unit for inputting an electric signal from the PON processing unit to the light sending unit, and the light sending unit Monitoring the optical signal from the optical signal, monitoring the presence or absence of abnormality of the optical signal, inputting the abnormality detection signal at the time of abnormality detection to at least the PON processing unit, and controlling the optical signal transmission stop And a monitoring unit.

  The abnormal optical output monitoring unit monitors the optical signal from the optical transmission unit, monitors whether it is the allocated transmission time from the collective line termination unit, and detects an abnormality when it deviates from the allocated transmission time. It can be configured to output a signal. Further, the optical signal from the optical transmission unit can be monitored to monitor whether or not the transmission frame format is predetermined, and when the transmission frame format is not satisfied, the abnormality detection signal can be output. Also, the optical signal from the optical transmission unit is monitored, whether the optical signal conforms to a predetermined code rule is monitored, and when the optical signal does not comply with the code rule, the abnormality detection signal is output. can do.

  The optical transmission unit may be configured to stop the transmission of the optical signal by an abnormality detection signal from the optical abnormality output monitoring unit or a control signal from the PON processing unit.

  The transmission control unit is configured to stop the input of an electrical signal for conversion into an optical signal to the optical transmission unit by an abnormality detection signal from the optical abnormality output monitoring unit or a control signal from the PON processing unit. Can be provided.

  In addition, the PON processing unit is configured to input an optical signal transmission stop control signal to one or both of the optical transmission unit and the transmission control unit based on an abnormality detection signal from the optical abnormality output monitoring unit. be able to.

  An optical signal transmission control method according to the present invention is an optical signal transmission control method in a PON system in which a plurality of subscriber line terminators are connected to an aggregate line terminator via an optical coupler and an optical transmission line. A PON processing unit for processing a signal; a light sending unit for converting an electric signal into an optical signal and transmitting; a sending control unit for inputting the electric signal from the PON processing unit to the light sending unit; and an optical abnormal output monitoring And monitoring the optical signal from the optical transmission unit by the optical abnormality output monitoring unit, monitoring the optical signal from the optical transmission unit for abnormalities, and stopping the transmission of the optical signal when an abnormality is detected This includes a process of performing control.

  Also, by monitoring the optical signal from the optical transmission unit by the optical abnormal output monitoring unit, monitoring whether it is the allocated transmission time from the aggregated line termination unit, when deviating from the allocated transmission time, It may include a process of outputting an abnormality detection signal and inputting it to at least the PON processing unit to perform control to stop the optical signal transmission from the optical transmission unit. In addition, the optical abnormality output monitoring unit monitors the optical signal from the optical transmission unit to monitor whether or not it is in a predetermined transmission frame format, and outputs an abnormality detection signal when it is not in the predetermined transmission frame format. At least the process of inputting to the PON processing unit and performing control for stopping the optical signal transmission from the optical transmission unit may be included. Further, the optical signal output from the optical transmission unit is monitored by the optical abnormal output monitoring unit to monitor whether or not the optical signal conforms to a predetermined code rule. The method may include a process of outputting an abnormality detection signal and inputting it to at least the PON processing unit to perform control to stop the optical signal transmission from the optical transmission unit.

  In addition, the optical transmission unit may include a process of performing optical signal transmission stop control based on an abnormality detection signal from the optical abnormality output monitoring unit or a control signal from the PON processing unit. The transmission control unit stops the input of an electrical signal for conversion into an optical signal to the optical transmission unit by an abnormality detection signal from the optical abnormality output monitoring unit or a control signal from the PON processing unit, A process of performing transmission stop control of the optical signal can be included. Further, according to the abnormality detection signal from the optical abnormality output monitoring unit, the PON processing unit inputs an optical signal transmission stop control signal to one or both of the optical transmission unit and the transmission control unit, and It is possible to include a process of performing signal transmission stop control.

  Each subscriber line termination unit ONU is provided with an optical abnormality output monitoring unit to monitor the optical signal transmitted from the optical transmission unit to the optical coupler, and any of the transmission time of the optical signal, the transmission frame format, the coding rule, etc. If one is not as specified, it is determined as abnormal and the transmission of the optical signal is stopped. Therefore, there is an advantage in the PON system and an abnormality occurs in one subscriber line terminating device ONU. However, there is an advantage that the system can be prevented from going down.

It is explanatory drawing of the PON system of Example 1 of this invention. It is principal part explanatory drawing of the optical signal transmission control apparatus of Example 1 of this invention. It is explanatory drawing at the time of the transmission timing abnormality of Example 1 of this invention. It is explanatory drawing at the time of the transmission frame abnormality of Example 1 of this invention. It is a flowchart of Example 1 of this invention.

  FIG. 1 is an explanatory diagram of a PON system, wherein 1 is a subscriber line termination unit ONU, 2 is an optical coupler, 3 is an aggregated line termination unit OLT, 4 is a user terminal, 11 is a PON processing unit, and 12 is a PON interface unit. (PON I / F), 13 is a memory unit, 14 is an interface unit (IF), and 15 is a power supply unit. A plurality of subscriber line terminators 1 are connected to the aggregated line terminator 3 via optical couplers 2 through optical couplers 2 to form a PON system. A subscriber line termination device 1 includes a PON processing unit 11 having a transmission / reception control function, a PON interface unit 12 that performs transmission / reception processing of an optical signal via the optical coupler 2, and a memory that stores a main signal buffer, a control program, and the like Unit 13, interface unit 14 for connecting to user terminal 4 such as a personal computer, and power supply unit 15 that inputs an AC power supply voltage such as AC 100 V and converts it into DC and supplies DC operating power to each unit. The optical signal transmission control device is configured by the optical signal transmission control means in the PON processing unit 11 and the PON interface unit 12.

  The collective line terminating device 3 assigns a transmission time including a transmission start timing and a transmission continuation time to the subscriber line terminating device 1 connected via the optical coupler 2, and the transmission time is It can be determined according to the request for the number of transmission request subscriber line termination devices, transmission band, and the like.

  FIG. 2 shows a main part of the optical signal transmission control apparatus, showing a functional part for transmitting an optical signal in the PON processing unit 11 and the PON interface unit 12 in FIG. Includes a transmission control unit 16, a light transmission unit 17, and a light abnormality output monitoring unit 18. Although not shown in the figure, the function of receiving the optical signal from the collective line terminating device 3 via the optical coupler 2 can be applied to various known optical signal receiving configurations.

  The PON processing unit 11 includes a function of performing transmission control according to an assigned transmission time including a transmission start timing and a transmission continuation time designated by the aggregated line termination device 3 while performing transmission / reception processing of data as an electrical signal. The optical transmission unit 17 includes an optical module including a laser diode that converts an electrical signal into an optical signal. The optical signal converted by the optical module is transmitted to the collective line terminating device 3 via the optical coupler 2. It is what has. The transmission control unit 16 includes a function of controlling the light transmission unit 17 in accordance with an electrical signal from the PON processing unit 11.

  The abnormal optical output monitoring unit 18 monitors the optical signal from the optical transmission unit 17 to determine whether there is an abnormality. As an abnormality detection, whether the allocated transmission time, transmission frame, code rule, etc. are normal or not. As described above, the transmission start timing information and the transmission continuation time information notified from the aggregated line termination device are output from the PON processing unit 11 to the optical abnormal output. This is notified to the monitoring unit 18. Accordingly, the optical abnormality output monitoring unit 18 determines that an abnormality has occurred when the optical signal from the optical transmission unit 17 starts transmission earlier than the allocation transmission start timing or when transmission continues for longer than the allocation transmission duration time. To do. If the transmission frame length information is notified and set in advance from the PON processing unit 11 to the optical abnormality output monitoring unit 18, and the transmission frame length by the optical signal from the optical transmission unit 17 does not match the set transmission frame length, a predetermined Since the transmission frame is not configured, the optical abnormality output monitoring unit 18 determines that an abnormality has occurred.

  The PON processing unit 11 notifies the optical abnormality output monitoring unit 18 of single or multiple types of frame format information, monitors the optical signal from the optical transmission unit 17, and notifies the frame format. If the frame format is different, it is determined that an abnormality has occurred. Also, code conversion is performed when converting an electrical signal to an optical signal, and conversion code rules such as NRZ code and 4B5B and 8B10B are applied. The code rule information is output from the PON processing unit 11 to an abnormal optical output. If the optical signal monitored by the light abnormality output monitoring unit 18 does not comply with the notified code rule, it is determined that an abnormality has occurred.

  When the abnormal optical output monitoring unit 18 determines that an abnormality has occurred, the abnormal detection signal is notified to at least one of the PON processing unit 11, the transmission control unit 16, and the optical transmission unit 17 to transmit the optical signal. Stop. Alternatively, one or both of the transmission control unit 16 and the light transmission unit 17 from the PON processing unit 11 is controlled as indicated by a dotted line arrow in accordance with the abnormality detection signal input from the optical abnormality output monitoring unit 18 to the PON processing unit 11. Transmission can be stopped.

  This transmission stop control is performed by, for example, cutting off the drive power supply to the optical module of the optical transmitter 17, cutting off the electric signal input to the optical module, blocking the optical signal from the optical transmitter 17 using an optical switch, The optical signal is blocked by any one or a plurality of blocking means such as blocking of an electric signal as transmission data from the PON processing unit 11 to the optical transmission unit 17 and blocking of an electric signal as transmission data from the PON processing unit 11 to the transmission control unit 16. Block sending. As a result, the malfunctioning subscriber termination device can spontaneously stop the transmission of the optical signal and continue the communication of the other subscriber line termination devices.

  FIG. 3 shows a case of abnormal transmission start timing. As shown in FIG. 3A, from the collective line termination device to the subscriber line termination devices ONU # 1, ONU # 2, ONU # 3, ONU # 4,. When the transmission start timing is assigned to the other subscriber line termination device ONU # 1, the transmission start timing of the own subscriber line termination device ONU # 2 is indicated as the transmission timing deviation occurrence. When it overlaps with time, the data by the optical signal within this overlapped time becomes error data. Therefore, the PON processing unit 11 notifies the optical abnormal output monitoring unit 18 of the allocation transmission timing information from the aggregated line termination device, and the optical abnormal output monitoring unit 18 monitors the transmission optical signal and follows the allocation transmission start timing. Since the occurrence of an abnormality is detected and the transmission of the optical signal is stopped by monitoring whether or not the transmission is performed at the same timing, it is possible to eliminate the interference with the transmission optical signal of the other subscriber line termination unit ONU # 1. it can.

  4A and 4B show a case where (A) monitors whether or not the transmission frame format is normal, and (B) monitors whether or not the transmission frame length is normal. Show the case. In the case shown in (A) where abnormality is detected by transmission frame format comparison, for example, a format conforming to ATM (Asynchronous Transfer Mode), IEEE 802.3, etc. is held in the database in the subscriber terminal unit ONU, and the format information is stored. The abnormal light output monitoring unit 18 is notified, and compared with the transmission frame format monitored by the abnormal optical output monitoring unit 18. Stop signal transmission.

  When an abnormality is detected by comparing the frame lengths (B), if the frame length of the transmission frame by the monitored optical signal does not match the preset frame length, the PON processing unit 11 and the transmission control unit 16 It is determined that an abnormality has occurred in any of the optical transmitters 17 and transmission of the optical signal is stopped as described above.

  FIG. 5 shows a flowchart of abnormality detection of the optical abnormality output monitoring unit 18 in steps (1) to (6). The optical transmission unit 17 converts the optical transmission unit 17 into an optical signal according to the transmission signal from the optical transmission unit 17 in FIG. The optical output control unit 18 performs frame output comparison (2), frame transmission time comparison (3), and frame transmission timing comparison (4). Is determined to be normal light output (5), and if it is determined to be abnormal in any of the comparison steps, it is determined that an abnormality has occurred and light output stop (6) is controlled. Note that any one of the comparison steps (2), (3), and (4) can be applied, and comparison for determining whether or not there is a code rule violation such as a 4B5B code rule or an 8B10B code rule. Steps can also be included.

Industrial applicability

  The PON system configured to detect the occurrence of abnormality in the optical abnormality output monitoring unit 18 and stop the transmission of the optical signal so as not to interfere with other subscriber line termination devices ONU is provided to the collective line termination device OLT. Thus, the present invention can be applied to a configuration in which 16 subscriber line terminator ONUs are connected via an optical coupler, a configuration in which 32 subscriber line terminator ONUs are connected, and the reliability of the PON system can be improved.

Claims (14)

In an optical signal transmission control device in a PON system in which a plurality of subscriber line terminators are connected to an aggregate line terminator via an optical coupler and an optical transmission line,
A PON processing unit that processes a transmission / reception signal; an optical transmission unit that converts an electrical signal into an optical signal to transmit; a transmission control unit that inputs an electrical signal from the PON processing unit to the optical transmission unit; and the optical transmission The optical signal from the unit is monitored to monitor whether there is an abnormality in the optical signal, and the abnormality detection signal at the time of abnormality detection is input to at least the PON processing unit to control the transmission stop of the optical signal An optical signal transmission control device comprising: an output monitoring unit.   The optical anomaly output monitoring unit monitors the optical signal from the optical transmission unit, monitors whether it is an allocated transmission time from the aggregated line termination unit, and when the deviation from the allocated transmission time, 2. The optical signal transmission control device according to claim 1, wherein the optical signal transmission control device has a configuration for outputting an abnormality detection signal.   The optical abnormality output monitoring unit monitors an optical signal from the optical transmission unit, monitors whether the transmission frame format is a predetermined one, and outputs the abnormality detection signal when the transmission frame format is not used. The optical signal transmission control device according to claim 1, comprising: an optical signal transmission control device according to claim 1;   The optical abnormality output monitoring unit monitors the optical signal from the optical transmission unit, monitors whether the optical signal conforms to a predetermined code rule, and when the optical signal does not comply with the code rule, 2. The optical signal transmission control device according to claim 1, wherein the optical signal transmission control device has a configuration for outputting an abnormality detection signal.   2. The optical transmission unit according to claim 1, wherein the optical transmission unit is configured to stop transmission of an optical signal by an abnormality detection signal from the optical abnormality output monitoring unit or a control signal from the PON processing unit. The optical signal transmission control device described.   The transmission control unit is configured to stop an input of an electrical signal for conversion into an optical signal to the optical transmission unit by an abnormality detection signal from the optical abnormality output monitoring unit or a control signal from the PON processing unit. The optical signal transmission control device according to claim 1, wherein   The PON processing unit includes a configuration in which an optical signal transmission stop control signal is input to one or both of the optical transmission unit and the transmission control unit based on an abnormality detection signal from the optical abnormality output monitoring unit. The optical signal transmission control device according to claim 1, wherein: In an optical signal transmission control method in a PON system in which a plurality of subscriber line terminators are connected to an aggregate line terminator via an optical coupler and an optical transmission line,
A PON processing unit that processes transmission / reception signals, an optical transmission unit that converts electrical signals into optical signals and transmits them, a transmission control unit that inputs electrical signals from the PON processing unit to the optical transmission unit, and an abnormal optical output And monitoring the optical signal from the light transmission unit by the optical abnormality output monitoring unit, monitoring the presence or absence of abnormality of the optical signal from the optical transmission unit, and transmitting the optical signal when abnormality is detected An optical signal transmission control method comprising a process of performing control to stop.   The optical abnormality output monitoring unit monitors the optical signal from the optical transmission unit, monitors whether it is the allocated transmission time from the aggregated line termination unit, and if there is a deviation from the allocated transmission time, 9. The optical signal transmission control according to claim 8, further comprising a step of performing a control of outputting a detection signal and inputting it to at least the PON processing unit to stop the optical signal transmission from the optical transmission unit. Method.   The optical abnormality output monitoring unit monitors the optical signal from the optical transmission unit, monitors whether or not the transmission frame format is predetermined, and outputs an abnormality detection signal at least when the transmission frame format is not predetermined. 9. The optical signal transmission control method according to claim 8, further comprising a step of performing control to stop optical signal transmission from the optical transmission unit by inputting to the PON processing unit.   By monitoring the optical signal from the light sending unit by the abnormal light output monitoring unit, monitoring whether or not the optical signal conforms to a predetermined code rule, when not an optical signal conforming to a predetermined code rule, 9. The optical signal transmission according to claim 8, further comprising a process of outputting an abnormality detection signal and inputting it to at least the PON processing unit to stop the optical signal transmission from the optical transmission unit. Control method.   9. The optical transmission unit according to claim 8, further comprising a process of controlling the optical signal transmission stop by the abnormality detection signal from the optical abnormality output monitoring unit or the control signal from the PON processing unit. Optical signal transmission control method.   In response to an abnormality detection signal from the optical abnormality output monitoring unit or a control signal from the PON processing unit, the transmission control unit stops input of an electrical signal for conversion into an optical signal to the optical transmission unit, 9. The optical signal transmission control method according to claim 8, further comprising a step of performing signal transmission stop control.   Based on the abnormality detection signal from the optical abnormality output monitoring unit, the PON processing unit inputs an optical signal transmission stop control signal to one or both of the optical transmission unit and the transmission control unit, and the optical signal 9. The optical signal transmission control method according to claim 8, further comprising a step of performing transmission stop control of the optical signal.

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