JPH05268339A - Performance monitor system - Google Patents

Abstract

PURPOSE:To manage transmission quality based on logic error by transmitting information performing CRC-6 arithmetic to a transmitting DSI from a transmission station to a reception station while inserting it in a prescribed time slot(TS), generating error information from this arithmetic information and transmitted signals at the reception station, returning the error information to the transmission station, and detecting this information at the transmission station. CONSTITUTION:The arithmetic information calculated by a CRC-6 arithmetic part 2 is inserted to the specified TS by an inserting part 6 and transmitted to a transmission line by a transmission station 100. At a reception station 200, the CRC-6 of the received DSI signal is calculated again by a rearithmetic part 10, the result is collated with the transmitted TS by a collation part 11, and the presence/absence of logic error is checked. Then, the result is inserted to the DSI signal to be transmitted in an error counter form by the reception station 200, and informed as error information. The transmission station 100 extracts the specified TS in the signal and detects the error information by an error information detection part 19. Thus, the performance of the counter station can be monitored.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a performance monitor system, and more particularly to ESF (Extended Superframe Forma).
The present invention relates to a performance monitoring system for subscriber-system transmission devices in North American primary group DS1 signal frame formats other than t), that is, SLC-96 and SF (Superframe Format).

The DS1 signal is mainly a remote terminal device (RT: Re) which is located at a place distant from the central office switch by multiplexing the telephone voice signal (DS0 signal) of a general subscriber by 24 time division.
It is used for the purpose of transmitting a voice signal to a mote terminal) and vice versa. With the spread of digital services (DDS) such as computer communication and subscriber leased line services such as ISDN in recent years, As compared with the transmission quality required for signal transmission, stricter quality is required.

Further, regarding the operation / management / maintenance method of the subscriber system transmission equipment including the DS1 signal transmission line, the maintenance person directly goes to the remote terminal equipment located far away from the station building and has a trouble. Although we have been dealing with it, in recent years it has shifted to a centralized management system in the station building,
Along with this, customers are also demanding functions such as performance / monitor failure prediction, and switching of the working line to a spare line when the performance exceeds a certain threshold.

[0004] Further, as a result of the mild regulation of the telecommunications business by the US government, free competition has intensified and profits have deteriorated depending on telephone companies.
It is necessary to consider this because there is a background that the arrangement does not proceed and the active device continues to be used.

[0005]

2. Description of the Related Art The construction of a subscriber digital transmission apparatus in North America and its application are shown in FIGS.

FIG. 5 shows an application in the case where the central office switch is an analog switch. In the case of the United States, it is difficult to install a station CO (Contral Office) in each area because the country is wide and the subscribers are scattered. , Which is simply referred to as RT) is installed and distributed to each subscriber from there. However, since the exchange interface is analog, the analog signal is once converted to a digital signal due to the problem of signal attenuation in long distance transmission. Converted to R
It needs to be transmitted to T38.

In the figure, a subscriber signal line-A that interfaces with a local exchange LAS (Local Analog Switch) 31 in a station CO is a device COT (Central Office).
In the CH / INF section 32 in the Terminal 37, each subscriber signal line A is subjected to analog / digital conversion, signaling information is added, and the signal is input to the MLDM section 33 as a multiplexing section. In the MLDM section 33, CH / INF
The subscriber signal lines A output from the unit 32 are collectively time-division multiplexed in units of 24 units, and a 1.544 Mbps signal is used as the FPSW unit or the FPSW & TSI unit 34 as a switching unit.
Output to.

In this case, the FPSW unit is a block having a function of switching to the protection transmission line side and relieving when a failure occurs in the working transmission line, and the FPSW & TSI unit is an F unit.
This is a block in which a subscriber time slot interchange function (TSI) is added to the function of the PSW unit.

1.544 output from the FPSW unit 34
The Mbps signal is encoded (AMI or B8ZS) in the LINE / INF unit 35, unipolar / bipolar converted, and transmitted to the RT38 as the primary group DS1 or T1 signal-B on the transmission line. At RT38, the above operation is reversed. In this operation, the DS1 or T1 signal B input from the transmission path is separated into subscriber signal units and distributed to each subscriber.
The same applies to the transmission from RT38 to COT37.

Further, if necessary, the transmission device operation support system (OS) 40 in the station building CO can be used to notify the alarms, device states, and operation modes generated in COT 37 and RT 38 via the controller 36 in COT 7. Make settings, etc.

In the application shown in FIG. 6, the local exchange LAS 31 shown in FIG. 5 is replaced with an LDS (Local Digital Switch) 9 from an analog type to a digital type, and this LDS is used.
When the interface of 39 directly supports the DS1 signal, the operation is the same as that of RT38 in FIG.

Signal B shown in FIGS. 5 and 6 is the North American primary group D.
This is a S1 (or T1) signal, and the frame format of this signal is shown in FIG. 7 (1). A frame is a frame bit Fi and a digitized voice signal of a subscriber called time slot TS or It is composed of areas for inserting digital data and signaling information. One frame is composed of 24 time slots each having one frame bit and 8 bits as a basic unit (see FIG. 7 (2)), and 1 + 24 × 8 = 193
Bit speed 125 μsec, ie 1.544 Mbp
It is sent to the transmission line at s.

Usually, a collection of several frames is referred to as a multi-frame, and one multi-frame is composed of a fixed number n of frames.
The value of depends on the frame format. There are currently three types of frame formats as shown in FIG. 7C, and in the SLC-96 format, n = 72, that is, 72.
One multi-frame is composed of these frames, and n = 12 in SF format and n = 2 in ESF format.
It is supposed to be 4.

The fact that one multi-frame is composed of n frames means that there are n frame bits Fi in one multi-frame. In the transmission device, the n frame bits have various functions. In the SLC-96 format, this frame bit (s) is used for synchronization detection, signaling information detection, maintenance, and data link information for notifying a player of alarm information. The SF format is used for synchronization detection and signaling information detection, and the ESF format is used for synchronization detection, signalling information detection, C for data link and performance monitor.
It is used for the purpose of RC-6 (cyclic code) information.

Here, of the above three types of frame formats, the ESF format has been devised in recent years, and is not yet widespread at this stage, but the SLC-96 format or the SF which is currently widespread. In terms of format, the performance of the transmission line and transmission equipment,
That is, there is Bipolar Violation (BPV) as a measure for measuring the transmission quality. The unipolar data signal transferred in the transmission device is converted into a bipolar (positive / negative polarity bipolar data) format before being sent out to the transmission line, and sent out to the transmission line consisting of two lines of T line and R line respectively. It

The bipolar signal format is AM according to the code rule.
Two types, I method and B8ZS method, are widely used. Bipolar Violation (BPV) is A according to the above two coding rules caused by a transmission line or a transmission device.
Two types, the MI system and the B8ZS system, are frequently used.
Bipolar violation (BPV) is a method of checking transmission quality by detecting the above two code rule errors caused by a transmission line or a transmission device.

[0017]

In the above, in the most popular transmission apparatus at present, it is stated that the performance, that is, the transmission quality is checked by the bipolar violation. The reasons (1) to (3) that the performance monitor based on the violation alone is extremely insufficient will be described below.

(1) First, the spread of digital services and new leased line services can be mentioned. In the case of conventional telephone services, the target signal is a voice signal, so even if a data error occurs due to the transmission path or transmission device, the effect on the voice signal will be a little hard to hear, and such a big problem will occur. Absent. Therefore, a bipolar violation is sufficient as a performance monitor.

However, the digital service (D
In the case of DS), since the target data is digital data, not analog voice, the influence of data error is extremely large. Therefore, the management of transmission quality is essential to provide better subscriber services,
With the current transmission quality control method using bipolar violation, it is possible to detect the coding rule error of the bipolar signal, but not the bit error in the data contents.
That is, the logic error of the data which does not become the bipolar violation cannot be detected.

This problem applies not only to DDS but also to new leased line services such as ISDN. In the case of the leased line service, particularly high quality service is required, and it is fatal that the logic error detection is impossible.

(2) Derived from the above problem, since the logic error of the data cannot be detected in the bipolar violation, the failure of the transmission line or the transmission device based on the logic error and the switching to the protection line are currently used. Then it is impossible.

(3) Due to the above two problems, it is impossible to comprehensively manage the transmission quality based on the logic error by the OS in the station building.

On the other hand, of the three types of frame formats of the DS1 (or T1) signal, the ESF format has CRC-6 information (which will be described later) added to the frame bits as described above, and is still popular. Not what I did. In order to apply this ESF format, the existing transmission equipment and exchange must be replaced with those compatible with the ESF format. This is being done gradually, but it would be prohibitively expensive to completely replace it.

The function of the frame bit in the SLC-96 format and the SF format is already assigned, and it is impossible to assign it to the logic error detection application. Since it is not possible to maintain compatibility with the devices widely used in the above, this is also impossible and there is a cost problem.

Therefore, in consideration of the compatibility with the existing device, it is necessary to enable the detection of the logic error in the method in which the scale of the method change is minimized.

Therefore, the present invention uses a frame format such as ESF that does not have CRC information.
In the S1 (or T1) signal, two time slots that are not assigned to subscribers in one multi-frame are used as data bit operation information at the own station (transmitting station) and at the opposite station (receiving station). The purpose of the present invention is to enable transmission quality control based on logic errors by a performance monitor method assigned for notification of logic error detection results.

[0027]

A performance monitor system according to the present invention for achieving the above object is conceptually shown in FIG. 1, in which a transmitting station 100 performs CRC-6 on a transmitted signal. An arithmetic unit 2 for performing an arithmetic operation, and an arbitrary predetermined one of the DS1 signals after performing the CRC-6 arithmetic operation.
The receiving station 200 is provided with an inserting unit 6 that inserts the operation information of the CRC-6 operation into a time slot and transmits it to the receiving station.
Is a re-calculation unit 10 that performs CRC-6 calculation again on the received DS1 signal, and compares the calculation result with the calculation information extracted from one time slot in the DS1 received signal to obtain error information. And a collating unit 11 for generating the error information, the error information being set to another predetermined one of the DS1 signals.
Transmitting to the transmitting station 100 using a time slot,
The transmitting station 100 is provided with an error information detecting section 19 which detects the error information for the transmission data of the transmitting station 100 itself.

[0028]

The operation of the configuration of the system of the present invention shown in FIG. 1 will be described below with reference to the DS1 (or T1) frame format shown in FIG.

First, in the transmitting station 100, the CRC-6
The operation information calculated by the operation unit 2 or the BIP-8 operation unit 3 is inserted into the TS 24 by the insertion unit 6 and sent to the transmission path, and the CRC of the received DS1 signal is received by the receiving station 200.
-6 or BIP-8 is re-calculated by the re-calculation unit 10 or 12, and the re-calculation result and the extracted TS24 are collated by the collation unit 11 or 12, and the logic
Check for errors.

The reception station 20 receives the result as error information in the form of an error count or an error rate.
It is inserted in TS01 of the DS1 signal transmitted by 0 and notified. Of course, at this time, CRC-6 including TS01
/ BIP-8 calculation is performed, the other party is notified, and the transmitting station 100 that has received this DS1 signal extracts TS01 in the signal, detects error information in the error information detection unit 19, and recalculates accordingly. Performance monitoring of the game becomes possible.

In this example, CRC-6 / BIP-8
The information insertion slot is TS24 of the last frame in a certain multi-frame, and the error information (performance monitor information) of the transmitting station 100 notified from the receiving station 200 is TS01 of the first frame. This is an example. And, if determined in advance, any time slot (TS) in the multi-frame may be used.

The above-mentioned performance monitor information may be accumulated with a time parameter added, and it can be accessed from an external transmission device operation support system (OS). ,
If it is detected that the preset logic error threshold is exceeded, it is possible to switch to the backup line side. Furthermore, the pseudo-error pattern insertion function and the loopback control function allow the maintenance of the transmission device including the transmission path to be performed very effectively.

[0033]

FIG. 3 is a functional block diagram showing an embodiment of a performance monitor system according to the present invention.
Is a frame bit (F bit) setting unit, 2 is CRC-
6 operation unit, 3 BIP-8 (bit interleaved parity) operation unit, 4 test pattern (TP) generation unit, 5 selector, 6 operation information insertion unit, 7 F bit insertion unit, 8 Is a remote loopback (RLB) control unit, 9 is a local loopback (LLB) control unit, 10
Is a CRC-6 recalculation unit, 11 is a CRC-6 error detection unit (ERR / DET), 12 is a BIP-8 recalculation unit, 13
Is a BIP-8 error detection unit (ERR / DET), 14 is a selector, 15 is a RAM, 16 is a CPU, 17 is an OS interface unit (OS / INF), 18 is a selector,
19 is a performance information detector (PM / DET), 2
0 and 21 are line interface units (LINE.
INF), and 22 are frame bit detectors.
Incidentally, these structures can be installed in the MLDM 3 or the LINE.INF 5 shown in FIG. 5, for example.

Next, the operation of this embodiment will be described. First, the frame bit set unit 1 is the transmitting side unipolar DS.
The F (frame) bit of one signal is set to "1" prior to the CRC-6 calculation, and the CRC-6 calculation unit 2 performs the CRC-6 calculation of the transmission side unipolar DS1 signal.

Here, the CRC-6 arithmetic method means that in a bit stream in one multi-frame, F bits are "1", each data bit is a coefficient of a polynomial with respect to X, and X ⁶ And the generator polynomial (X ⁶
Divide by + X + 1), send the remaining 6 bits to the game as CRC bits, recalculate by the same method in the game, compare the result with the received CRC bits (6 bits), and if the same, logic error No, if it is different, it is a method to process with logic error.

Returning to FIG. 3, the BIP-8 arithmetic unit 3 performs the BIP-8 arithmetic operation on the transmission side unipolar DS1 signal.

FIG. 4 shows this BIP-8 arithmetic system. In this system, except for the F bit in the unipolar DS1 signal, the first bit of each bit of the time slot to be operated, It is a system that calculates horizontal and even parity of 8 bits in total, such as 2 bits, and inserts that information into a predetermined time slot position for each multi-frame and sends it to the game.
On the receiving side, the calculation is performed again by the same calculation method, and the contents are compared with the contents of the received parity information for each multi-frame.

The selector 5 is a CRC-6 system and a BIP-8 system.
A selector 14 which will be described later selects a selection signal for selecting a method.
When the CRC-6 or BIP-8 operation information is received by the operation information insertion section 6 and the insertion section 6 receives a predetermined D
CRC on any time slot (TS24) in S1
-6 The information calculated by the calculation unit 2 and the BIP-8 calculation unit 3 is inserted. Then, in the F-bit insertion unit 7, CRC-6
The original correct F bit is reinserted into the F bit temporarily set during the operation.

At this time, the game loopback (RLB) control unit 8
9 and 9 and the local station loopback (LLB) control unit are both used to isolate a failure occurrence point. For example, when a certain transmission quality is deteriorated, COT, R
When it is desired to verify which of T (see FIG. 5) is causing the deterioration, the COT side performs its own loopback, and when the logic error disappears, it is estimated that the deterioration is caused by the RT side including the transmission path. Yes, and if the logic error disappears after the game is turned back on the COT side, COT,
It can be inferred that RT is causing deterioration without any problem on the transmission path. This facilitates maintenance of the transmission device.

As described above, the DS1 signal received through the line interfaces 20 and 21 after being looped back to itself or looped back to its own station, has the F bit set by the F bit detector 22, and the CRC-6 calculator 2 And BIP-
No. 8 of the DS1 signal sent to the CRC-6 recalculation unit 10 and the BIP-8 recalculation unit 12, which perform the same calculation as the calculation unit 3 respectively, and received by the error detection units 11 and 13 as the collation units respectively. Assigned time slot (T
The CRC-6 information inserted in S24) is collated to check whether or not a logic error has occurred. Then, the collation result is generated as error information in the form of an error count or an error rate.

The error information of the error detectors 11 and 13 is sent to the selector 18 in the CRC-6 system or BIP-8.
The signal is selected according to the method, and the selection signal at this time is given from the selector 14. The output signal of the selector 18 can be stored in the RAM 15 via the CPU 16 as the performance information of the game (remote). At this time, CPU
16 stores the performance information in the RAM 15 by adding a time parameter. At the same time this information is FPS
It is also sent to the W section (see FIG. 5) and can be used as a trigger for switching to the backup line based on a logic error.

Although not shown, the error (performance monitor) information thus generated is externally inserted into a predetermined time slot (TS01) of the transmission signal and returned to the transmission station.

In the performance information detecting section 19 in the transmitting station, a predetermined one-time period in which the result (error information) re-computed by the opposite station for the DS1 signal transmitted by itself is inserted. When the slot (TS01) is extracted and the game is notified by the error count, the error count information is notified, and when the game is notified by the error rate, the error rate information is added with the time parameter via the CPU 16. Then, it is stored in the RAM 15 section and is further output to the FPSW section.

The selector 14 is CRC-6 / BIP-.
The method of selecting which method of 8 is to be used is selected by a switch (hardware) or a CPU (software), and is input to the selection signals of the selectors 5 and 18. Also, the test pattern generator 4
In response to a trigger from the CPU or the like, the pseudo error pattern is inserted into the transmission DS1 signal in the arithmetic units 2 and 3 to cause the opposite station to detect it, and to notify it of the transmission including the transmission path including the transmission path. This is for self-diagnosis of the transmission quality of the device.

Further, the OS / INF section 17 for interfacing with the OS (see FIG. 5) in the station building sets the performance monitor method from the OS, and the performance monitor results of the own station and the game stored in the RAM. Analyzes and executes commands such as notification of.

[0046]

As described above, according to the performance monitor method of the present invention, the transmission DS1 or T1 signal is transmitted from the transmitting station to the receiving station by CRC-6 or BIP-.
8 calculations are performed and the information is inserted into a predetermined arbitrary 1 time slot and sent, and the receiving station collates this calculation information with the result obtained by recalculation from the transmission signal to generate error information. The transmission line and the transmission device are designed in consideration of a new subscriber service that will grow in the future, without replacing the transmission equipment that is currently in widespread use with a new one because the transmission station is configured to detect it and return it to the transmission station. Maintenance of the
That is, it has an extremely great effect on the monitoring of logic errors, the failure prediction and the preliminary switching based on the logic errors, and the unified management by the OS of those stations.

In the system of the present invention, two time slots in a DS1 (or T1) signal cannot be assigned to a subscriber, but considering the effect of this system, two time slots in one multi-frame are logically allocated. -The advantages assigned to the performance monitor for errors far outweigh the disadvantages.

[Brief description of drawings]

FIG. 1 is a block diagram showing the principle configuration of a performance monitor system according to the present invention.

FIG. 2 is a diagram showing an example of a frame format of a DS1 signal applied to the performance monitor system according to the present invention.

FIG. 3 is a diagram showing an example of a transmission procedure by a performance monitor method according to the present invention.

FIG. 4 is a diagram showing a bit interleaved parity (BIP-) used in the performance monitor system according to the present invention.
8) An explanatory diagram of a calculation / detection method.

FIG. 5 is a block diagram showing a universal application (analog system) of a subscriber transmission device.

FIG. 6 is a block diagram showing an integrated application (digital system) of a subscriber system transmission device.

FIG. 7 is a diagram illustrating a frame structure of a DS1 signal.

[Explanation of symbols]

 100 transmitting station 200 receiving station 2 CRC-6 operation unit 3 BIP-8 operation unit 6 insertion unit (operation information insertion unit) 10 CRC-6 recalculation unit 12 BIP-8 recalculation unit 11, 13 collation unit (error detection unit ) In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (11)

[Claims] 1. In a method of performing performance monitoring of a subscriber transmission apparatus using a DS1 signal having a format not including CRC-6 information, a transmitting station (100) performs a CRC-6 operation on a transmission signal. The operation unit (2) to perform and the DS-6 after performing the CRC-6 operation.
The receiving station (200) is provided with an inserting section (6) for inserting the operation information of the CRC-6 operation into one predetermined time slot of one signal and transmitting it to the receiving station. CR for the DS1 signal
A re-calculation unit (10) for performing C-6 calculation again, and a collation unit (11) for collating the calculation result with the calculation information extracted from one time slot in the DS1 received signal to generate error information.
And sending the error information to the transmitting station (1) by using another predetermined one arbitrary time slot of the DS1 signal.
00), and the transmission station (100) is provided with an error information detection unit (19) for detecting the error information for the transmission data of its own station. 2. A BIP-8 instead of the CRC-6 operation.
The performance monitoring method according to claim 1, wherein the performance monitoring method is performed. 3. The performance monitor system according to claim 1, wherein a BIP-8 operation can be executed in addition to the CRC-6 operation, and any one of them can be selected. 4. The transmission station (100) according to claim 1, wherein the error information received from the reception station (200) is added with a time parameter and accumulated. Performance monitor method. 5. The performance monitor system according to claim 4, wherein the error information is accessible from an external transmission device operation support system. 6. The performance monitor system according to claim 1, wherein the working line is switched to the protection line based on the error information. 7. The performance monitor system according to claim 1, wherein an error count number is used as the error information. 8. The performance monitor system according to claim 1, wherein an error rate is used as the error information. 9. The performance according to claim 1, wherein the transmitting station (100) comprises a test pattern generating section for inserting a pseudo error pattern into the DS1 signal.・ Monitor method. 10. The transmitting station (100) loops back the DS1 signal at its own station or a receiving station (200) of the opposite station to perform CRC of its own station.
6. The performance monitor system according to claim 1, wherein the recalculation unit (10) and the collation unit (11) generate error information. 11. The performance monitor system according to claim 1, wherein a T1 signal is used instead of the DS1 signal.