JPS6288450A - Line supervisory system - Google Patents

Abstract

PURPOSE:To improve the reliability of a digital radio communication line by detecting earlier the fault of a reception synchronizing switch before a fading takes place really and the switching is executed. CONSTITUTION:The data signal of each active radio system is sent sequentially in parallel to a spare radio system PROT according to a control signal from a switching controller at the normal operation where no parity error is detected, the data signal subjected to timing adjustment through a frequency division storage circuit 72 and a sequence conversion circuit 74 is compared with a data signal sent from each radio system by a bit collation circuit 76, and when a coincidence signal 104 is obtained, it is discriminated that the operation of the circuits is normal. In this case, no switching signal 103 is inputted and no actual changeover is executed. When no coincidence signal 104 is obtained even after a prescribed time (a time required for sequential conversion and bit collation by the sequence conversion circuit) conversely, since it is discriminated that any circuit operation is faulty, an alarm signal is sent to inform the abnormity.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a line monitoring system, and in particular to a line monitoring system for digital wireless communication lines that performs synchronous switching with no bit errors between a working radio system and a standby radio system. Regarding.

[Conventional technology]

In general, digital wireless communication lines employ a synchronous switching method that allows switching between a working wireless system and a standby wireless system without pitting errors in order to prevent line failures due to aging and the like.

In other words, each working radio system of the receiving terminal station is provided with a reception synchronization switcher, which performs timing adjustment (synchronization adjustment) between data signals transmitted in parallel from the transmitting terminal station to the working radio system and the backup radio system. ) to confirm that the bit timings of the data signal (first data signal) transmitted by the working wireless system and the data signal (second data signal) transmitted via the backup wireless system completely match. It is configured to perform switching without momentary interruption after confirmation. In order to control this synchronization switching between active and backup, the receiving end station constantly monitors the frame synchronization signal and parity check pulse of each radio system, and detects parity errors and checks them as determined in advance. When a threshold is exceeded, a switching control signal (parallel transmission and switching command) is sent out to perform switching.

[Problem that the invention seeks to solve]

The conventional line monitoring method described above can detect deterioration in transmission quality due to equipment failures and fading in the main equipment that makes up each wireless system, but the reception synchronization method installed in each working wireless system at the receiving terminal station It is not possible to detect equipment failures in the switch. The reception synchronization switch includes many IC circuits for timing adjustment, and if one of these circuits fails, normal switching will not be possible, but unless switching is actually performed, there will be no abnormality. Often undetected. Therefore, there is a problem in that when fading occurs and synchronization switching is to be performed, switching is impossible due to a failure of the receiving synchronization switch, resulting in communication failure.

SUMMARY OF THE INVENTION An object of the present invention is to provide a line monitoring system that can detect device failures in a reception synchronization switch at an early stage, solve the above-mentioned problems, and improve the reliability of digital wireless communications.

[Failure to solve the problem]

The line monitoring method of the present invention uses a standby radio system and N (N≧
In a line monitoring method for a digital wireless communication line that performs bit error-free synchronous switching with (an integer of 1) working radio systems, transmission is performed by each of the working radio systems from a transmitting terminal station according to a predetermined sequence. The data signals are sequentially sent in parallel to the backup radio system, and a reception synchronization switch provided in each of the working radio systems of the receiving terminal station selects the first data signal transmitted by each of the working radio systems and the backup radio. detecting a coincidence between a second data signal transmitted in parallel through the system, and detecting a coincidence between said first data signal and said second data signal within a predetermined time
The structure is such that the tube axis No. f6 is sent out when coincidence with the data signal cannot be obtained.

〔Example〕

Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a digital wireless communication line switching system for explaining an embodiment of the line monitoring system of the present invention. In FIG. 1, data signals Zoo-1 to Zoo-10 sent from a multiplexing terminal device (not shown) on the transmitting terminal side are
0-n are each divided into two by a hybrid 1, and one is a code conversion board 2 that converts bipolar code into unipolar code.
and each working radio system R, EG-1 to RF via the transmission 16 code processing board 3 which inserts additional pits for radio section monitoring.
! G-n, and the other one can be connected in parallel to the standby radio system PROT via switchers 4-1 to 4-n. On the receiving end station side, the received and demodulated output of each working radio system is transmitted through a frame synchronization board 5. After passing through the reception code processing board 6 and removing the additional bits, it is added to the reception synchronization switchers 7-1 to 7-n, where it is transmitted by the backup radio system PROT and branched from the reception distribution board 8.
The configuration is such that timing adjustment with No. 6 is performed and synchronization switching is performed after confirming that both signals match. Reception synchronization switch 7-1
The outputs of ~7-n and the reception distribution board 8 are each converted into bipolar codes by a code conversion board 9, and the former is sent to a multiplexing terminal equipment (not shown) via a switch 10, and the latter is sent to a pilot detector 11. Sent out. Note that the pilot detector 11 faces the pilot transmitter 12 on the transmitting terminal station side and performs comprehensive monitoring of the standby radio system system.

In the above configuration, switching between active and backup when fading occurs is performed by the reception code processing board 6 of each radio system.
This is done using a switching control signal sent when a parity error is detected. In other words, the current non-stop system REG
-1, when parity ttb occurs, the switching device 4-1 on the transmitting terminal side is operated to send the data signal 100-1 to the working radio system RJG-1 and the backup radio system PROT in parallel, and the receiving terminal The reception synchronization switch 7-1 on the side receives the data signal 10 transmitted by the working wireless system R) 3G-1.
1 and the data signal 102 which is transmitted in parallel to ``6-Miya'' by the backup radio system PROT and branched by the reception distribution board 8, and after confirming the coincidence of both data signals, the data signal 101 is transmitted from the data signal 101. Switch to data signal 102.

FIG. 2 is a block diagram showing an embodiment of the reception synchronization switch 7-1 shown in FIG. 1. Data signals 101 input from the reception code processing boards 6 of the working radio systems R and EG-1 and data signals 102 input from the reception distribution boards 8 of the backup radio systems PR and OT are stored in frequency division storage circuits 71 and 72, respectively. and a switching circuit 75 via column order conversion circuits 73 and 74.
and is sent to the code conversion board 9 switched by the switching signal 103. The frequency division memory circuits 71 and 72 are N
A circuit uses a circuit that sequentially reads input signals using N divided clock signals with different phases, and then uses a common clock signal of the same frequency (N divided frequency) to temporarily store them as N parallel signals. , the column order conversion circuits 73 and 74 adjust the bit timing of the input signal of the frequency division storage circuit by shifting the order of reading out the N parallel signals using the clock signal of the original frequency. This is a circuit that performs the following. Column order conversion circuit 73. The outputs of '14 are branched and applied to a bit matching circuit 76, which performs code matching for each bit, and sends out a match signal 104 when all codes of a certain length match. When performing synchronous switching to prevent line failures due to fading, when the above-mentioned coincidence signal 104 is confirmed by the switching control device, the switching signal 1 is
03 is input and switching is performed. In addition, the changeover switch 7
Reference numeral 7 denotes a switch for switching the readout order conversion operation of the column order conversion circuit. When switching from the working radio system to the backup radio system, the column order conversion circuit 74 on the backup radio system side adjusts the timing. After switching to the standby radio system, the column order conversion circuit 73 on the working radio system side performs timing adjustment.

In the line monitoring method of the present invention, during normal operation when no parity error is detected, the data signals of each working radio system are sent to the 11th secondary radio according to a predetermined sequence according to the control signal from the switching control device. System PR
The data signal sent in parallel to the OT and whose timing has been adjusted through the frequency division storage circuit 721 and the column order conversion circuit 74 is matched with the data signal transmitted by each wireless system by the bit comparison circuit 7.
6, and if a match signal 104 is obtained, it is determined that these circuits are operating normally. Of course, at this time, the switching signal 103 is not input and actual switching is not performed. On the other hand, even if a certain period of time (the time to change the column order in the column order conversion circuit and perform bit matching) has passed, the coincidence signal 10
If 4 is not obtained, it is determined that there is an abnormality in the operation of one of the circuits, and the system is configured to send out an alarm signal to notify of the abnormality. Therefore, before fading actually occurs and switching is performed, a device failure in the reception synchronization switch can be discovered at an early stage, and the reliability of the digital wireless communication line is improved. Since the above-mentioned monitoring operation is aimed at detecting equipment failure of the reception synchronization switch,
It is not necessary to repeat the process continuously, but it is sufficient to repeat it periodically at appropriate time intervals. Of course, when switching due to fading is required, the monitoring operation is immediately stopped and the switching operation is started.

The line monitoring system of the present invention is not limited to the configuration of the switching system shown in FIG.
Needless to say, the present invention can also be applied to a switching system in which a transmission synchronization switch is inserted after the transmission code processing board 3 of a backup radio system and a reception synchronization switch is provided before the reception code processing board 6. Further, although the case where there is one standby radio system has been described, the same applies to the case where there are two or more systems.

〔Effect of the invention〕

As explained above, according to the line monitoring method of the present invention,
By early detection of equipment failure of the reception synchronization switch,
This has the effect of improving the reliability of digital wireless communication lines by preventing a situation where fading occurs and an abnormality is discovered during actual switching and switching becomes impossible.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a switching system of a digital wireless communication line for explaining an embodiment of the present invention, and FIG. 2 is a block diagram of an embodiment of the reception synchronization switch of FIG. 1. be. 1...Hybrid, 2,9...Code change board, 3...Transmission ■ Code processing board, 4-1.4
-n, 10...Switcher, 5...Frame synchronization board, ll...Pilot detector, 12...
...Biput multiplier, 71°72...
Frequency division storage circuit, 73.74...column order conversion circuit,
75...Switching circuit, 76...Bit verification circuit, 77...Switching switch.

Claims (1)

[Claims] In a line monitoring method for a digital wireless communication line that performs synchronous switching with no bit errors between a backup wireless system and N (an integer of N≧1) working wireless systems, The data signals transmitted by each working radio system are sequentially sent in parallel to the backup radio system, and the reception synchronization switch provided in each working radio system of the receiving terminal station transmits the data signals transmitted by each working radio system. detecting a coincidence between one data signal and a second data signal transmitted in parallel via the standby wireless system, and detecting a coincidence between the first data signal and the second data signal transmitted in parallel through the backup wireless system; A line monitoring method that is characterized by sending out an alarm signal when a signal cannot be matched.