JPH0322729A - Method for specifying quality degradation section - Google Patents

Abstract

PURPOSE:To easily specify the quality degradation section by applying the same signal from a transmission terminal station to an in-use line to be tested and a stand-by line and sending the output signal of a stand-by reception and demodulation part out of each repeater station requentially through the in-use line to be tested. CONSTITUTION:When a reception terminal station 15 detects the error rate of data from an in-use line (M1 and M2), e.g. M1 decreasing below a prescribed value, a signal 1 is applied to the stand-by line (PROT) as well. Here, recepter station 13 sends the signal 1 passing through the PROT, to the reception terminal station 15 through the M1 and the reception terminal station 15 compares the error rate of the signal passing entirely through the M1 with the error rate of the signal 1 passing through the POT only between the transmission station 12 and repeater station 13 to judge that the quality degradation section is not the M1 between the transmission terminal station 12 and repeater 13 when they nearly coincide with each other, and then performs the operation, at every repeater. Consequently, the quality degradation section can easily be specified.

Description

[Detailed Description of the Invention] [Summary] The purpose of the present invention is to easily identify a quality degradation section used in a digital wireless line having a relay station, and to identify the quality degradation section in a digital communication system. The output signals of the working and backup reception/demodulation sections are branched into first and second output signals, and the branch output signal corresponding to the first selection signal to be applied is selected from the first branch output signal. branch/selection means; and selection means for selecting either the second branch output signal or the input test signal in response to the applied second selection signal and sending the selected signal to the working and preliminary modulation/transmission sections; to send the test signal from one end of the line under test to the other, or provide another branching means or selection means to send the same signal from the transmitting terminal station to the working line under test and the protection line. In addition, each relay station sequentially transmits the output signal of the preliminary reception/demodulation section via the working line under test. The configuration is such that it is sent to the receiving terminal station.

[Industrial application field]

The present invention relates to a method for identifying a quality deterioration section used in a digital radio line having a relay station.

Generally, digital wireless communications require multiple relays as line length increases.

On the other hand, relay stations are becoming increasingly unmanned, but this is done in order to be able to respond quickly in the event of a failure. Monitoring is performed by remote control from manned terminal stations, but this monitoring only monitors equipment failures.

Therefore, the section of the digital wireless line where the quality has deteriorated. In other words, it is necessary to easily identify the quality deterioration section.

[Conventional technology]

FIG. 4 shows an example of a line configuration diagram.

As shown in the figure, there are two
13 relay stations. 14 has been installed, and two working lines M
It is assumed that a wireless line is configured with one Mz (hereinafter abbreviated as +MI+Mz) and one protection line PROT (hereinafter abbreviated as PROT).

Now, when both M, and M2 are operating normally, the input signal 1 and signal 2 are sent to the line switching unit 11, the transmitting terminal station 12, and the Ml
+ is sent to relay station 13 via M2. Relay station l3 regenerates and relays the signal and sends it to relay station l4. Similar to the relay station 13, the relay station 14 regenerates and relays the signals and sends them to the receiving terminal station, and the receiving terminal station reproduces the signals 1 and 2 and outputs them via the line switching section 16.

However, when the receiving terminal station 15 detects that a failure has occurred in +M1, it requests parallel transmission to the transmitting side via, for example, a control line (not shown) to send signal 1 to PROT as well. On the transmitting side, the corresponding transmitting end parallel switch (not shown) in the line switching unit l1 is driven to switch the receiving end changeover switch (not shown) in the line switching unit l6 to the PROT side on the signal l. The line switching is completed.

FIG. 5 shows a block diagram of a conventional example. Here, the relay station has PROT. There are repeaters for MI+M2, but since all of these repeaters operate in the same way, we will explain the operation of the repeater for M1.

A transmission signal from an upper station is received by a receiver 21 via an antenna, where the received signal is frequency-converted, amplified to a predetermined level, and output to a demodulator 22. After being demodulated and reproduced by a demodulator, it is applied to a modulator 23 to modulate a carrier wave, and is sent to a lower station by a transmitter 24 at a predetermined transmission frequency and output.

[Problem to be solved by the invention]

Now, in Fig. 4, for example, transmitting terminal station l2 and relay station 1
If the line quality between 3 and 3 deteriorates. The signal with degraded quality is sent to the relay station 13. 14 and taken out at the receiving terminal station 15. This is the first time that it is known that the line quality has deteriorated, but there is a problem in that it takes time for maintenance personnel to go to each relay station and check, for example, to identify the degraded section.

An object of the present invention is to enable easy identification of quality deterioration sections.

[Means to solve problems]

FIG. 1 shows a block diagram of the principle of the present invention.

In the figure, 41. 51 is a working and preliminary reception/demodulation unit that receives and demodulates a signal from an upper station; 42. 52 generates a modulated wave using a manually generated signal and generates a modulated wave at a predetermined frequency.
This is the active and preliminary modulation/transmission section that is sent out at the output.

Further, 61 branches the outputs of the working and standby receiving/demodulating sections into first and second outputs. A branching/selecting means for extracting a branch output corresponding to the applied first selection signal from the first output, and 62 branches the output signal of the preliminary reception/demodulation section into third and fourth branch output signals. and is branching means for sending the fourth branch output signal to the preliminary modulation/transmission section.

Further, 71 selects a second selection signal corresponding to the applied second selection signal.
A selection means that selects either the branch output or the manually input test signal and sends it to the working and preliminary modulation/transmission sections.
72 is a selection means for selecting either the third branch output signal or the output signal of the working receiving/demodulating section in accordance with the applied third selection signal and sending the selected signal to the working modulating/transmitting section. It is.

[Effect]

As shown in FIG. 1(a), the present invention provides a branching/selecting means on the output side of the working and standby receiving/demodulating sections of a relay station, and a selecting means on the manual side of the working and standby modulating/transmitting sections.

Then, when checking the quality of the line under test, the relay station connected to one end of this line sends a test signal to the line under test via the working modulation/transmission unit based on the applied second selection signal. .

On the other hand, the relay station connected to the other end extracts this test signal via the working receiving/demodulating section and sends it to the branching/selecting means. Since the branching/selecting means selects and sends out a test signal according to the applied first selection signal, the quality of the line under test is determined by checking the error state of the sent out test signal.

In the case of FIG. 1(b), branching means is provided in the preliminary reception/demodulation section, and selection means is provided on the input side of the active modulation/transmission section.

When the quality of the working line deteriorates, the signal applied to the working line whose quality has deteriorated is also applied to the protection line, and each relay station uses the third selection signal to signal the output of the protection reception/demodulation section. By sequentially sending the signals to the receiving terminal station via the line under test, the receiving terminal station can identify the period of quality deterioration.

It is assumed that the first to third selection signals are applied from the terminal station via the control line as described above.

〔Example〕

Figure 2 is a block diagram of an embodiment of the present invention. FIG. 3 shows a block diagram of another embodiment of the invention.

Here, the receiver 411 and the demodulator 412 are structural parts of the preliminary reception/demodulation section 41, the receiver 511 and the demodulator 512 are the structural parts of the active reception/demodulation section 51, and the branch circuits 8611 to 613
, the selection circuit 614 is a component of the branching/selection means 61, the selection circuits 711 to 713 are component parts of the selection means 71, the modulator 421 and the transmitter 422 are a component of the preliminary modulation/transmission section 42, and the modulator 52l ．． A transmitter 522 represents a component of the currently used modulation/transmission section 52.

Further, the branch circuits 621 to 622 are part of the structure of the 1,000-stage branch 62. Selection circuits 721 and 722 indicate the configuration of the selection means 72.

below. Protection line (PROT) 1, working line Tsukuda. M2)
2, the operation shown in FIG. 2 will be explained.

During normal operation, the signal from the upper station input via M1 is received by the receiver 511 and then sent to the demodulator 512.
A reproduced signal obtained by demodulation and reproduction is applied to the modulator 521 via a branch circuit 612 and a selection circuit 712.

Therefore. The modulated wave is generated by this modulator, converted into a predetermined frequency and power by the transmitter 51, and then sent to the lower station. Incidentally, each device of M2 and PROT operates in the same way as in the case of shame.

On the other hand, when checking the quality of the line under test, the second selection signal is used to drive, for example, the selection circuit 712, and the output of the test signal generator 72 is applied to the modulator 521. A test signal is then sent to the lower station via transmitter 522.

The receiver 511 of the lower station receives the signal from the upper station, performs frequency conversion, amplifies it to a predetermined level, and sends it to the demodulator 512. Therefore, a test signal is taken out from the demodulator 512, but this test signal is branched by a branch circuit 612 and applied to a selection circuit 614.

Since the lth selection signal for selecting the output of the branch circuit 612 is applied to this circuit, a test signal is taken out and applied to the error detection circuit 62' to check the line quality.

Here, each relay station detects the error rate of the corresponding relay section and sends the detection result to the receiving end station. The receiving end station can easily identify the quality deterioration section.

next. The operation shown in FIG. 3 will be explained. still. In the case of Figure 2, the line quality is checked at the relay station, but in this case, the line quality is checked at the terminal station. below.
The method shown in FIG. 3 will be explained using FIG. 4.

For example, when the receiving terminal station 15 detects that the error rate of the data from the peak is below the specified value, it also applies the signal 1 to PROT as described above. Therefore, at relay station l3, PR
The signal l that has passed through OT is sent to the receiving terminal station via H, and all the receiving terminal stations are The error rate of the signal l that has passed through PROT is compared, and if they almost match, it is determined that the quality degradation section is not the old one between the transmitting terminal station and the repeater 13.

If this is done for each repeater, the quality deterioration section can be identified at the receiving terminal.

Now, in FIG. 3, the branch circuit 621 sends the horizontal output of the demodulator l2 to the selection circuit 721 through the modulator 421 and the branch circuit 622. Add to 722. The outputs of the demodulator 512 and L demodulator are also added to this selection circuit, but during normal operation, the outputs of the demodulator 512 and the demodulator for L are added. The output of the Mz demodulator is selected and sent to the lower station.

However, for example, if the line quality in Mt.
Since the selection signal of PR is applied to the selection circuit 721,
The signal l passed through the OT is sent to the modulator 521 and the transmitter 522 +
It is sent to the lower station via MI.

Since each relay station sequentially performs the above operations, the receiving terminal station can easily identify the line quality deterioration section from the state of change in the error rate.

52 is a working modulation/transmission section; 61. 62 is a branching/selection means; 71. 72 indicates selection means.

〔Effect of the invention〕

As described above in detail, the present invention has the advantage that a quality deterioration section can be easily identified.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the principle of the present invention, Fig. 2 is a block diagram of an embodiment of the invention, Fig. 3 is a block diagram of another embodiment of the invention, Fig. 4 is an example of a line configuration diagram, Figure 5 is a block diagram of a conventional example. In the figure, 41 is a preliminary reception/demodulation section, 42 is a preliminary modulation/transmission section, 5l is a working reception/demodulation section, and filter C.

Claims (1)

[Claims] 1. At least one relay station is provided between a transmitting terminal station and a receiving terminal station, and the transmitting terminal station and the receiving terminal station are connected to a plurality of working lines and one via the relay station. The relay station receives and demodulates the signal from the upper station, and generates a modulated wave using the input signal to the working and backup reception/demodulation sections (41, 51). In a digital communication system provided with working and preliminary modulation/transmission sections (42, 52) that transmit at a frequency and output of Second
branching/selecting means (61) for selecting a branch output signal corresponding to the applied first selection signal from among the first branch output signals, and a second selection signal to be applied; A selection means (71) is provided for selecting either the second branch output signal or the input test signal in accordance with the signal and sending it to the working and preliminary modulation/transmission sections, and the selection means (71) selects either the second branch output signal or the input test signal in accordance with the signal and sends it to the working and preliminary modulation/transmission sections. A quality deterioration section identification method characterized by transmitting the test signal at the end. 2. In the digital communication system according to claim 1, the output signal of the preliminary reception/demodulation section (41) is branched into third and fourth branch output signals, and the fourth branch output signal is split into third and fourth branch output signals. A branching means (62) that sends out to the preliminary modulation/transmission section (42), and a third branch output signal and an output signal of the working reception/demodulation section (51) in response to the applied third selection signal. a selection means (72) for selecting one of the following and sending it to the working modulation/transmission unit (52), and applying the same signal to the working line under test and the protection line from the transmitting terminal station, A method for identifying a quality deterioration section, characterized in that the station sequentially sends the output signal of the preliminary reception/demodulation section to the receiving terminal station via the working line under test.