JPH0620193B2 - Line monitoring method - Google Patents

Description

The present invention relates to a line monitoring system, and more particularly to a line monitoring system used in a digital wireless communication system having two or more protection lines.

[Conventional technology]

A wireless communication system often adopts a system standby method in order to remedy a line disconnection due to fading.

In a digital wireless communication system adopting a system standby system, in addition to line switching by a coaxial switch, synchronous switching by a transmission switching circuit composed of an electronic circuit provided on the transmission side and a synchronization switching circuit provided on the reception side (for example, Japanese Patent Application Laid-Open No. 2000-242242). Sho 55-143850
It is customary to prevent the occurrence of a code error due to a momentary disconnection at the time of line switching by also making it possible.

In the system standby system, a test signal is transmitted to a standby standby line, and the transmitted test signal is detected on the receiving side to monitor the communication quality of the standby circuit.

Most of the conventional system protection schemes used in digital wireless communication systems are N: 1 systems with one protection line for the number N of working lines, but N has become higher as the demand for line reliability increases. In recent years, the system spare system for the pair 2 has also been proposed.

[Problems to be solved by the invention]

In a digital wireless communication system using two or more protection lines, there are two or more protection lines in standby and 1
It may be a line. A line monitoring method for constantly monitoring the communication quality of each standby line in standby according to each of these cases has not been proposed so far.

An object of the present invention is to provide such a line monitoring system.

[Means for solving problems]

The line monitoring system of the present invention uses two or more protection lines for transmitting a test signal when in a standby state, and uses the protection line of a digital wireless communication system for synchronously switching the working line to the protection line when the communication quality deteriorates. In the line monitoring method for monitoring, the test signal sending means for sending the same test signal to all the standby lines in the standby state, and the two or more of the standby lines are alternated when they are in the standby state. When only one is in a standby state, a control signal generating means for generating a control signal for designating it and a synchronous switching means for selecting and outputting the test signal transmitted by the protection line designated by the control signal A test signal detecting means for detecting the quality of the output of the synchronization switching means and outputting a detection result; and a standby state based on the output of the test signal detecting means and the control signal. Constructed and a protection line monitoring means for monitoring a communication quality of a said protection line.

〔Example〕

Preliminary 2 of the present invention with reference to the drawings showing the following embodiments
The case of the system will be described in detail.

1 and 2 are block diagrams showing a receiving terminal station 2 and a transmitting terminal station 1 which constitute an embodiment of the line monitoring system of the present invention.

The transmitting terminal station 1 shown in FIG. 2 outputs a test signal generator 93 which outputs a test signal 140 which is a specific pattern of a bi-boler.
And a hybrid 11.12 that divides and outputs a bipolar input signal 101.102 sent from a multiplexing carrier terminal device (not shown) and a transmission switching control device (not shown). Synchronous switching devices 21 and 22 for selecting and outputting any one of the input from the hybrid 11 and 12 and the input from the coaxial switching device 22 and the test signal generator 93.
And a transmission code processing circuit 3S for converting the output of the coaxial switching device 21 into a uni-bola signal, converting the speed, inserting an additional bit such as a frame synchronization signal / parity check bit, scrambling, and bisecting it, and the hybrid 11
The transmission code processing circuits 31 and 32 for processing the output of 12 in the same manner as in the transmission code processing circuit 3S and dividing the output into three
And the output of the transmission code processing circuits 3S, 31 and 32, and any one of these three inputs is controlled by the transmission switching control device to be selected and output as the modulation input signals 11S1 and 11S2. And is configured. Of the outputs of the transmission code processing circuits 31 and 32, the modulation input signals 111 and 112 and the modulation input signals 11S1 and 11 that are outputs that are not output to the transmission switching circuits 4S1 and 4S2.
The S2 is input to each transmitter (not shown) and wirelessly transmitted by the working lines SYS1 and SYS2 and the protection lines SP1 and SP2.

The receiving terminal station 2 shown in FIG. 1 has a demodulated signal 12S1.1 which is an output of a receiver (not shown) of the protection lines SP1 and SP2.
2S2 is input, frame synchronization is performed, a parity check is performed to detect deterioration of the code error rate, and the input is divided into 3 to output the frame synchronizing circuits 5S1 and 5S2 and the working line S.
The frame synchronization circuit 5S1 receives the demodulated signals 121 and 122 output from the YS1 and SYS2 receivers (not shown).
As in the case of 5S2, the frame synchronization circuits 51 and 52 which reproduce the frame synchronization signal and detect the deterioration of the code error rate and output the inputs as they are, and the outputs of the frame synchronization circuits 5S1 and 5S2 are input and these two inputs are input. And a frame switching circuit 5S1, 5S2.5, and a synchronous switching circuit 6S which are controlled by the control signal 180 to select and output one of the two.
1 output or frame synchronization circuit 5S1, 5S2, 5
Synchronous switching circuits 61 and 62 for inputting the output of 2 and selecting and outputting any one of these 3 inputs under the control of a receiving switching control device (not shown), and synchronous switching circuits 6S and 61.6
The output of No. 2 is descrambled, the additional bits are removed, the speed is converted, and the received code processing circuits 7S, 71 and 72 for converting to a bibola signal and output, and the received code processing circuit 7S. One of the outputs of 71 is selected and output as the output signal 131, and when the output of the reception code processing circuit 71 is selected, the signal 150 which is the output of the reception code processing circuit 7S is output to the coaxial switch 82. The output signal 13 is selected by selecting one of the output of the reception code processing circuit 72 and the signal 150 output by the coaxial switching device 81 under the control of the coaxial switching device 81 and the reception switching control device.
2 and outputs the signal 150 to the test signal detector 95 when the output of the reception code processing circuit 72 is selected, and the signal 15 from the coaxial switch 82.
Test signal detector 9 for inputting 0 and outputting detection signal 160
4, a control signal generator 95 for inputting the status signal 170 from the reception switching control device and outputting a control signal 180, and a protection line monitoring circuit 96 for inputting the detection signal 160 and the control signal 180. There is.

The operation of the embodiment shown in FIGS. 1 and 2 will be described.

First, the case where all the circuits are normal will be described.

In this case, the input signals 101 and 102 are the hybrid 11
Input to the transmission code processing circuits 31 and 32 via 12,
Converted into modulated input signals 111 and 112, working line SYS
1 · SYS2 is transmitted. Working line SYS1 ・ S
The YS2 demodulated signals 121 and 122 are the frame synchronization circuit 5
The signal is input to the synchronous switching circuits 61 and 62 via 1/52, is selectively output, and is output by the reception code processing circuits 71 and 72.
It is converted to 1.132 and output to the receiving side multiplexed carrier terminal (not shown) via the coaxial switching devices 81 and 82.

On the other hand, the test signal 140 is input to the transmission code processing circuit 3S via the coaxial switching devices 22 and 21, is converted into a signal, is input to both of the transmission switching circuits 4S1 and 4S2, is selected, and is output as the modulation input signal 11S1 and 11S2. Line SP1
It is transmitted by SP2. The demodulated signals 12S1 and 12S2 of the protection lines SP1 and SP2 are the frame synchronization circuit 5S1 and
Input to the synchronization switching circuit 6S via 5S2. The control signal generator 95 detects from the line status signal 170 that both the standby lines SP1 and SP2 are on standby, and controls the synchronous switching circuit 6S by the control signal 180 to synchronously switch the frame synchronous circuits 5S1 and 5S2. The output of is alternately output at a constant cycle. This output is the reception code processing circuit 7
The signal is converted into a signal 150 at S and is output to the test signal detector 94 via the coaxial switching devices 81 and 82. The signal 150 is
The test signal 140 transmitted by the protection line SP1 and the test signal 140 transmitted by the protection line SP2 are alternately switched.

The test signal detector 94 detects the signal 150 and outputs the detection result as a detection signal 160. Backup line monitoring circuit 9
6 monitors the communication quality of the protection lines SP1 and SP2 alternately by sampling the detection signal 160 in synchronization with the switching of the synchronous switching circuit 6S by the control signal 180.

Next, a case where the working line SYS1 is switched to the protection line SP1 by synchronous switching will be described.

When the frame synchronization circuit 51 detects that the code error rate of the working line SYS1 has deteriorated due to fading or the like, the reception switching control device detects this and the protection line SP1.
Output a switching command to.

The synchronization switching circuits 61 and 62 are connected to the frame synchronization circuit 5S1.
It has a selection switch for selectively outputting one of the outputs of 5S2, and a synchronization switch for synchronously switching between the outputs of the frame synchronization circuits 51 and 52 and the output of the selection switch. The switching command controls the selection switch of the synchronization switching circuit 61 to selectively output the output of the frame synchronization circuit 5S1.
The switching command is also sent to the transmission switching control device. The transmission switching control device that has received this switching command is the transmission switching circuit 4S1.
Is controlled to selectively output the output of the transmission code processing circuit 31. As a result, the output of the transmission code processing circuit 31 is the working line S.
Y1 is transmitted in parallel by the protection line SP1. The frame synchronizing circuit 5S is accompanied by the switching operation of the transmission switching circuit 4S1.
Since the synchronization of 1 may be transiently disturbed, after confirming that the synchronization has been recovered and the code error rate has become normal, the reception switching control device controls the synchronization switch of the synchronization switching circuit 61 to perform the synchronization switching. By this switching, the reception code processing circuit 7
The input of 1 is the frame synchronization circuit 51 that has been input so far.
Is switched to the output of the frame synchronization circuit 5S1, that is, the signal transmitted by the protection line SP1, and the line switching is completed.

In this case, the test signal 140 is transmitted only by the protection line SP2. The control signal generator 95 uses the protection line SP1.
It is detected by the line state signal 170 that the switching command to the is issued, and the control signal 180 controls the synchronous switching circuit 6S to output only the output of the frame synchronous circuit 5S2.
As a result, the signal 150 is only the test signal 140 transmitted by the protection line SP2. Backup line monitoring circuit 96
Detects that only the protection line SP2 is on standby by the control signal 180, and detects the protection line SP2 by the detection signal 160.
Monitor the communication quality of.

The operation when the working line SYS1 is synchronously switched to the protection line SP2 or when the working line SYS2 is synchronously switched to the protection line SP1 or the protection line SP2 is the same as the operation in the above case. Monitor the communication quality of the standby line that is on standby.

The coaxial switch 21, 22, 81, 82 switches the line for a failure, such as a failure of the transmission code processing circuit or the reception code processing circuit, which cannot be repaired by the above-described line switching by the synchronous switching.

When the working line SYS1 is switched to the protection line SP1 by such line switching, the coaxial switch 21 outputs the output of the hybrid 11 to the transmission code processing circuit 3S, and the transmission switching circuit 4S1 selectively outputs the output of the transmission code processing circuit 3S. To do. As a result, the signal transmitted by the working line SYS1 is also transmitted by the protection line SP1. The control signal generator 95 detects this line switching by the line status signal 170 and controls the synchronization switching circuit 6S by the control signal 180 to selectively output the output of the frame synchronization circuit 5S1. The coaxial switch 81 outputs the output of the reception code processing circuit 7S as an output signal 131. In this case, the protection line SP2
Can be used for synchronous switching with the working line SYS2.

The embodiment of the present invention has been described above in the case where both the number of working lines and the number of protection lines are two.

It goes without saying that the present invention can be applied to the case where the number of protection lines is 3 or more, and the present invention can be applied to all the cases where the number of working lines is 1 or more.

[Effects of the Invention] As described in detail above, according to the present invention, in a digital wireless communication system using two or more protection lines, a line monitoring method for normally monitoring a standby protection line transmitting a test signal. And the line monitoring method of the present invention is economical because only one test signal detector is required for two or more backup lines.

[Brief description of drawings]

1 and 2 are block diagrams showing a receiving terminal station and a transmitting terminal station which constitute an embodiment of the line monitoring system of the present invention. 6S ... Synchronous switching circuit, 93 ... Test signal generator, 94
... Test signal detector, 95 ... Control signal generator, 96 ...
… Standby line monitoring circuit.

Claims (1)

[Claims] 1. A line for monitoring the protection line of a digital radio communication system, which uses two or more protection lines for transmitting a test signal in a standby state and synchronously switches the working line to the protection line when the communication quality deteriorates. In the monitoring system, a test signal transmitting means for transmitting the same test signal to all the standby lines in the standby state, and one or two of the standby lines alternately when the standby lines are in the standby state. Only when it is in standby,
A control signal generating means for generating a control signal for designating; a synchronous switching means for selecting and outputting the test signal transmitted by the protection line designated by the control signal; and detecting the quality of the output of the synchronous switching means. A test signal detecting means for outputting a detection result; and a protection line monitoring means for monitoring the communication quality of the protection line in the standby state based on the output of the test signal detecting means and the control signal. Line monitoring method.