KR101154649B1 - System for managing optical communication network using optical signal level and method for monitoring the system - Google Patents

Abstract

The present invention relates to an optical communication network management system including a plurality of optical communication devices. Each of the optical communication apparatuses includes: a transmission data processing unit for generating transmission data including optical state indication information of the optical communication apparatus; An optical signal transmitter for transmitting the transmission data to another optical communication device; An optical signal receiver for receiving transmission data from the other optical communication device; A reception data processor extracting quality information from the received data; And a system manager connected to the transmission data processor, the optical signal transmitter, the optical signal receiver, and the received data processor, wherein the system manager receives transmission level information from the optical signal transmitter and receives from the optical signal receiver. Receiving level information, receiving quality information from the received data processor, and determining an optical connection quality based on the received information.

Description

Optical network management system for monitoring optical network using optical signal transmission and reception level and method for judging abnormality of optical communication section {SYSTEM FOR MANAGING OPTICAL COMMUNICATION NETWORK USING OPTICAL SIGNAL LEVEL AND METHOD FOR MONITORING THE SYSTEM}

The present invention relates to a method for determining an optical communication abnormal section in an optical communication system, and more particularly, to an optical communication error section determining method for monitoring a level of an optical transmission / reception signal transmitted through an optical cable and monitoring an abnormal section of an optical communication system. It is about.

 An optical communication device is a device that transmits a large amount of data up to several hundred Gbps with a remote optical communication device a few hundreds of kilometers away by connecting an optical line to an optical signal transmission and reception unit inside the corresponding device.

If an error occurs in the transmission and reception of the optical signal due to an increase in the loss of the optical path between the optical communication devices or disconnection, an optical signal transmission / reception unit, etc., it causes a significant effect on the operation of the optical communication network such as a large line break or an error.

 Therefore, the general optical communication device monitors whether there is an optical signal abnormality, and the existing product monitors the optical signal breakage and the received data error rate only at the receiving circuit side in the optical communication device to generate an alarm when a problem occurs, so that the optical network operator can recognize and take action. have.

1 illustrates a principle of monitoring an optical signal abnormality in a conventional optical communication device.

The transmission service data is transmitted from the multiplexing unit (built in the optical communication apparatus) to the transmission data processing unit 106. Then, the transmission service data is transmitted to the optical signal transmission unit 106 via the TTL-ECL (Transistor-Transistor Logic-Emitter-Coupled Logic) conversion unit 103 and then transmitted to the remote device via the outdoor optical line.

The reception service data is received by the optical signal receiver 102 via an outdoor optical line. Then, the data is transmitted to the received data processor 107 via the ECL-TTL converter 104. The data is transmitted from the received data processing unit 107 to a multiplexing unit (built in the optical communication device).

The monitoring method for optical signal abnormality is as follows. First, the reception data processor 107 checks an error using an overhead of data received according to a frame structure defined by itself. Then, the received signal quality information by the error rate is reported to the system manager 105. In addition, the optical signal receiver 102 determines whether the optical signal is received and reports LOS (Loss Of Signal) information to the system manager 105.

Conventionally, various problems have occurred as only the optical signal receiving side monitors the existence of the optical signal and the received data error rate.

Specifically, it was not possible to accurately distinguish whether the cause of the optical signal monitoring alarm was the disconnection of the optical path or the increase of the loss, or the failure of the optical signal transmitter of the remote device. Therefore, it was necessary for the technician to measure and analyze the optical signal transmission / reception levels of the remote site and the local station by using a measuring instrument such as an optical power meter to determine a failure section. This method has a problem that the time required for the recovery of failure increases, which in turn causes a problem in the stable operation of the optical communication network requiring high reliability.

In addition, there is a problem in that the cost caused by the optical network maintenance technician dispatched to move between the two sides of the optical communication device several hundreds of kilometers away or on-site measurement to determine the failure zone.

In addition, as the number of years of use after the first installation of the optical communication device has increased, the possibility of a decrease in optical output of the optical signal transmitter and an increase in loss of connection points on the optical path is large.However, a situation in which the problem progresses until the receiving optical signal is completely disconnected cannot be identified. There was a limit to the prevention of optical network failure.

Lastly, in order to measure the optical signal during the inspection to prevent the failure of the optical communication device, the optical communication device and the optical line must be separated. Therefore, there is a cause of network failure due to human error and critical alarm ( There was a problem that caused a burden on the operator (such as communication related to the cause of the alarm to the tension department and related departments).

In the present invention, an optical communication network management system comprising a plurality of optical communication devices, each optical communication device comprising: a transmission data processing unit for generating transmission data including optical state indication information of the optical communication device; An optical signal transmitter for transmitting the transmission data to another optical communication device; An optical signal receiver for receiving transmission data from the other optical communication device; A reception data processor extracting quality information from the received data; And a system manager connected to the transmission data processor, the optical signal transmitter, the optical signal receiver, and the received data processor, wherein the system manager is configured to receive transmission level information from the optical signal transmitter and from the optical signal receiver. Receiving a reception level information, receiving quality information from the reception data processing unit, and determining an optical connection quality based on the transmission level information, the reception level information, and the quality information. to provide.

In the system, the optical connection quality may include an optical signal strength, optical signal interruption information or an error rate of the signal.

The optical communication apparatus further includes a conversion unit connected to the optical signal transmitter or the optical signal receiver and the system manager to convert the transmission level information or the reception level information into data that can be processed by the system manager. It may be an optical network management system.

The optical communication device may be an optical communication network management system, further comprising an optical state display unit for displaying on the optical communication device by using the optical connection quality information provided by the system manager.

The optical state display unit may be an optical communication network management system, characterized in that the LED alarm display or LCD display.

The optical state display unit may be an optical network management system, characterized in that for displaying the optical connection quality information in a plurality of predetermined steps.

The present invention provides a method for determining an optical communication abnormality interval in an optical communication network management system including a first optical communication device and a second optical communication device connected to the first optical communication device by an optical path, wherein the first optical communication is performed for a predetermined time period. Measuring a reception level of the second optical communication device according to the transmission level of the device and the reception level of the first optical communication device according to the transmission level of the second optical communication device, and storing the received level as reference data; Measuring an optical signal transmission level of the first optical communication device and retrieving a reception level of a corresponding second optical communication device from the reference data; If the reference data includes the reception level of the corresponding second optical communication device, the optical communication abnormal section determination method comprising the step of determining that there is the abnormal section in the first optical communication device.

The transmission level and the reception level may be displayed in a plurality of preset stages.

The reference data may be a database of measured values accumulated during the predetermined time.

When an alarm occurs, the cause of failure (optical communication device, optical path) can be identified immediately, which shortens the recovery time of optical network failure.

The construction of the facility eliminates the need for an optical signal level measurement process by an optical communication technician and a separate measuring device, and also eliminates the need for optical signal level measurement for fault recovery or preventive maintenance (periodical). Is obtained.

Failure prevention by constant monitoring of light signal level decrease by the secular variation and natural environment

(Reduced optical signal transmission power, increased loss of optical line section, etc.), and it is possible to improve reliability by improving optical network operation.

Through EMS and NMS function, it is possible to understand the optical connection status to remote optical communication device in detail.

1 illustrates a principle of monitoring an optical signal abnormality in a conventional optical communication device.
2 is a circuit diagram of an optical signal transmission and reception in an optical communication apparatus according to an embodiment of the present invention.
3 illustrates a method for measuring and correcting a light reception level according to an embodiment of the present invention.
4 illustrates optical transmission level measurement and correction according to an embodiment of the present invention.
5 shows an application example of the optical transmission / reception level measurement value according to the present invention.
FIG. 6 is a diagram illustrating a method of distinguishing and displaying regions of optical transmit / receive levels according to an exemplary embodiment.
7 shows an algorithm of the optical communication error section determination method according to the present invention.

The present invention provides the optical signal in the optical communication device itself in the installation and operation of the optical communication device.

Always measure and monitor the connection status and transmit / receive level. Accordingly, the present invention aims to shorten the time required to identify the failure point of the optical communication network, reduce the cost of repair and preventive maintenance, and ultimately implement an optical communication device that guarantees high quality and high reliability of the optical communication network.

As an implementation method, information indicating an optical signal transmission level, information indicating an optical signal reception level, information indicating whether or not an optical signal is received, and an error rate of a received signal

Use the information to identify the optical signal connection status between the optical communication devices

Display it.

In addition, the operator may not only remotely operate the optical communication device but also the optical communication device EMS (Equipment Management System) or the optical network NMS (Network).

Use Management System to understand.

2, an optical signal transmission and reception circuit diagram in an optical communication apparatus according to an embodiment of the present invention will be described.

The optical signal transmission / reception circuit includes an optical signal transmitter 201, an optical signal receiver 202, an A / D converter 203, a TTL-ECL converter 204, an A / D converter 206, and a transmission data processor. 207, the reception data processing unit 208, the system manager 209, and the optical state display unit 210 are included.

The optical signal transceiver 201, 202 connects an optical communication device (electrical signal) and an outdoor optical line (optical signal) and simultaneously converts an electrical signal into an optical signal or converts an optical signal into an electrical signal.

The TTL-ECL and ECL-TTL converters 204 and 205 convert TTL level signals used in general electronic circuits to ECL levels used in the optical signal transceiver and also inversely convert.

The A / D converter converts an analog value corresponding to the intensity of the optical signal extracted from the optical signal transmitter 201 and the optical signal receiver 202 into a digital signal suitable for representing, calculating, and transmitting the signal, so that the system manager 209 processes it. to provide. The A / D converter can express optical transmission / reception levels in a total of 4,096 steps corresponding to 12 powers of 2 as 12 bits.

The received data processor 208 extracts information on quality, such as an error rate, from the received data and provides it to the system manager 208. For example, the CRC (Cyclic Redundancy Check) value included in the header of the received and reproduced data is compared with the CRC value generated by itself.

To determine the received signal performance.

The transmission data processing unit 207 adds various optical state indication information of the host side to the transmission service data and transmits it to the counterpart station. Here, the transmission service data is transmission data for the original purpose of the communication that does not include overhead such as a header.

The system manager 209 receives the intensity of the optical transmission output from the optical signal transmitter 201 and the A / D converter 203. In addition, the optical signal receiver 202 and the A / D converter 206 receive the intensity of the optical reception signal. In addition, the optical signal receiver 202 receives optical signal interruption information (LOS) information. In addition, the reception data processing unit 208 receives the reception signal quality information. The system manager 209 comprehensively evaluates the optical connection quality based on all the received information and data.

The system manager 209 may check an error using an overhead of data received according to a frame structure defined by the reception data processor 208, and transmit received signal quality information according to an error rate. In addition, the optical signal receiver 202 may determine whether the optical signal is received and report LOS (Loss Of Signal) information to the system manager 209. The optical transmission level detected by the optical signal transmitter 201 and converted into 12 bits by the A / D converter 203 may be reported to the system manager. The optical reception level detected by the optical signal receiver 201 and converted into 12 bits by the A / D converter 206 may be reported to the system manager. The optical connection state information of the partner station sent through the transmission data processing unit 207 can be reported.

The optical state display unit 210 may display the optical communication device in hardware by using the optical connection quality information provided by the system manager 209. The hardware display includes an LED alarm display or an LCD display. In addition, the optical state display unit 210 is EMS (Equipment Management System) or optical network operation management for optical communication device operation management

Data available for use with NMS (Network Management System) software

Can provide.

The transmission service data in the optical communication apparatus according to the present invention is transmitted to the transmission data processing unit 207 from a multiplexer which can be embedded in the optical communication apparatus. The transmission service data is transferred from the transmission data processing unit to the TTL-ECL conversion unit 204 and converted into an ECL level signal that can be used in the optical signal transmission unit. The converted signal is transmitted to the outdoor optical path through the optical signal transmitter 201.

The reception service data according to the present invention is transmitted from the outdoor optical line to the optical communication device through the optical signal receiver 202. The received service data transmitted from the optical signal receiver 202 to the ECL-TTL converter 205 is converted from the ECL level to the TTl level. The converted received service data is transmitted from the optical signal receiver to the received data processor 208. The reception data processing unit extracts information on quality, such as an error rate of the received data, and provides the information to the system manager 208, and delivers the received service data to the multiplexing unit of the optical communication device.

Hereinafter, the optical transmission / reception level measurement and correction method of the present invention will be described with reference to FIG. 3.

The optical reception signal is converted into an electrical signal via the optical reception element. As a photoreceiving element, for example, a photodiode can be used. The optical reception signal converted into the electrical signal is connected to the reception data extraction circuit through an automatic gain control circuit (AGC) for coping with the loss variation in the optical path.

The optical reception level is measured by converting the voltage level of the analog electric signal through the optical reception element into a 12-bit digital signal (4,096 steps) through an A / D converter (A). Converts the magnification to suit the input range of the / D converter.

For example, if the magnitude of the electrical signal passing through the optical receiving element (A) is 0V? 0.5V and the proper input range (B) of the A / D converter is 0V? 5V, the amplification circuit (㉮) has 10 times the voltage amplification. For this purpose, the value of the resistor R2 is designed to be 10 times the resistance R1.

For more accurate light reception level measurement, correction is made in consideration of the conversion characteristics of the optical signal from the optical signal to the electrical signal. In addition, first, when the optical signal generator is connected to the optical receiving element input terminal and the intensity is applied to the minimum level at which the LOS (Loss Of Signal) signal, which is an optical signal interruption alarm, disappears, the optical signal generator output value and the A / D converter output value are minimum values. Decide on

After that, the optical output of the optical signal generator is gradually increased to increase the optical signal generator output value and the A / D converter output value when the maximum optical level without error is applied to the received data.

Decide on Evenly divide the difference between these minimum and maximum values into 12 bits (4,096 steps).

In this way, the magnitude of the optical reception signal can be measured.

4 illustrates optical transmission level measurement and correction according to an embodiment of the present invention. The optical transmitting element converts transmission data, which is an electrical signal, into an optical signal. The light transmitting element may be, for example, a laser diode. The optical transmitter passes through a BIAS Current Control & Cooling circuit (C) that prevents excessive flow of BIAS current so that the light output level is constant.

In order to measure the optical transmission level, the optical signal intensity value (Analog value) fed back from the LD element to the (C) circuit is used, and the operational amplifier (B) and the A / D converter (described in the optical reception level measurement and correction method) V) It can be converted into 12bit digital signal (4,096 steps) using the circuit.

Now, with reference to FIG. 5, the method of utilizing the optical transmission and reception level measurement value will be described. The optical transmission / reception level measured in the above-described manner may be reported to the EMS via the system manager 209. The EMS polls periodically to measure the level of optical transmission and reception at that time so that the operator can use it in a variety of ways, including:

The display device attached to the optical communication device itself can be monitored by the optical communication device operator. In this case, the display device may be a display device such as an LCD or an LED.

Measurement values of optical transmit / receive level are displayed on EMS for operation of optical communication device and NMS for operation of optical communication network.

It can be displayed as it is. In addition, as shown in Figure 5 can be easily monitored by dividing by region. The optical transmission and reception level measurement value may be utilized as analysis information by accumulating a database. Transmitting / receiving level value variation may generate an alarm when there is a change over a certain range compared to the previous value.

The division display for each area of the optical transmission / reception level may be arbitrarily set by the optical communication device operator using EMS or NMS. In FIG. 6, an area-specific division display of an optical transmission / reception level is illustrated. Of the total 4,096 steps, 0 to 100 can be set to Out of Range, 101 to 1,000 is Low, 101 to 3,000 is Normal, and 3,001 to 4,096 can be set to High.

7, an optical signal abnormality monitoring method and an abnormal section determination method will be described.

The cumulative statistics for each transmit and receive level between the own station and the counter station are performed. The cumulative statistics may be databased and stored as reference data. The reference data includes, for example, statistics in which the extent to which the level of the counterpart received signal decreases due to the decrease in the transmission level of the own station is within an acceptable range. If each level value is normal, the transmission level measurement and cumulative statistics continue.

If any of the level values is not normal, first, the local station transmitter, the counter station receiver, and the optical path therebetween are checked.

First, check whether the local light transmission level has decreased. If the other station's optical reception level decreases with the decrease of its own transmission level, there is no abnormality in the line. Therefore, it is determined that there is an abnormal section in the local optical transmission section. If the partner station optical reception level does not result from the decrease of the slave station optical transmission level, the optical path between the own station transmitter and the partner station receiver is checked.

If the local station optical transmission level has not decreased, then check whether the partner station optical reception level has decreased. If the partner station optical reception level is reduced, it is determined that there is an abnormality in the optical path between the own station transmitter and the partner station receiver, and the check is performed. If the partner station optical reception level has not decreased, the above-described process is carried out in the same manner for the partner station transmitter and the local station receiver and for the optical path connecting them.

The optical communication apparatus according to the present invention may periodically measure the optical transmit / receive level by the controller, and accumulate the optical transmit / receive level value on a daily, weekly, or monthly basis as well as in real time to provide operational data.

By analyzing the trend of the optical transmission / reception level measured as described above, it is possible to prevent failures by grasping in advance the characteristic change and the possibility of failure according to the secular variation of the optical transmission element. In addition, when the optical transmission level is normal and the reception level suddenly decreases or decreases continuously, by checking the optical path section and the optical connector connection point, it is possible to shorten the time to identify the abnormal section of the optical communication device and improve the reliability of the optical communication network. Provide useful information.

Claims (9)

delete delete delete delete delete delete A method for determining an optical communication abnormality section in an optical communication network management system including a first optical communication device and a second optical communication device connected to the first optical communication device by an optical path,
During the predetermined time period, the reception level of the second optical communication device according to the transmission level of the first optical communication device and the reception level of the first optical communication device according to the transmission level of the second optical communication device are measured and stored as reference data. step;
Measuring an optical signal transmission level of the first optical communication device and retrieving a reception level of a corresponding second optical communication device from the reference data;
And determining that there is the abnormal section in the first optical communication device if the reference data includes the reception level of the corresponding second optical communication device. The method of claim 7,
And the transmission level and the reception level are displayed in a plurality of predetermined steps. The method of claim 7,
And the reference data is a database of measured values accumulated during the predetermined time.

Images