JP3405453B2 - System and method for establishing synchronization of line switching device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless transmission device having a plurality of active wireless lines. More particularly, the present invention relates to a system and method for establishing synchronization of a line switching device for instantaneously switching between a standby wireless line provided for maintenance of a working wireless line and a working wireless line provided for maintenance and inspection.

[0002]

2. Description of the Related Art As a line switching device of the above-mentioned wireless transmission device, JP-A-10-224329 and JP-A-10-2 are available.
There is one described in Japanese Patent No. 85081. A line switching device of a wireless transmission device, which is a premise of the present invention, will be described below. FIG. 6 is a block diagram showing a schematic configuration of a line switching device of a wireless transmission device which is a premise of the present invention. It should be noted that the same components are denoted by the same reference numerals and numbers throughout the drawings for description.

As shown in the figure, a plurality of working N (N) are provided between the receiving side and the transmitting side of the line switching device of the wireless transmission device.
≧ 2) A wireless line, that is, an active first wireless line, an active second wireless line, ..., An active Nth wireless line, and a standby wireless line are provided. On the transmission side of the line switching device of the wireless transmission device, the interface boards 100 ₁ , 100 ₂ , ..., 100
_N is provided and the interface boards 100 ₁ , 100 ₂ ,
The signals to be transmitted are input to 100 _N , respectively.

The interface boards 100 ₁ , 100 ₂ ,
.., 100 _N is connected to a sending end switch 101, and when the one of a plurality of working N wireless circuits is deteriorated, the sending end switching device 101 outputs an input signal of the corresponding working wireless line to the working wireless line as a backup. The signal of the standby radio line is distributed to the radio line and switched from the pilot signal to the signal of the working radio line. Feed edge switch 101 transmits the signal processing board 102 ₀ spare radio channel in the transmission signal processing board ₁₀₂ 1 of the working radio channel,
102 _2, ..., 102 _N are connected, pre-radio channel transmission signal processing board 102 ₀ of the working radio channel transmission signal processing board _{102 1,} 102 2, ..., 102 _N may be input synchronizing clock signals, respectively.

The transmission signal processing board 10 for the spare radio line
2 ₀ In the normal condition, enter the pilot signal selected by the sending-end switch 101, on the basis of the clock synchronization signal,
A frame signal is formed and a pilot signal transmission process is performed.

Further, the transmission signal processing board 1 of the working radio line
02 ₁ , 102 ₂ , ..., 102 _N are the end switching devices 101.
Via the interface boards 100 ₁ , 100 ₂ , ...,
The transmission signals from 100 _N are input, the frame signals are formed based on the clock synchronization signals, and the transmission processing of the transmission signals is performed. Transmission signal processing board 102 _{0 for} standby radio line, transmission signal processing board ₁₀ for active radio line
Modulators 103 ₀ , 1 are provided for 2 ₁ , 102 ₂ , ..., 102 _N.
03 ₁ , 103 ₂ , ..., 103 _N are respectively connected,
Each of the modulation boards 103 ₀ , 103 ₁ , 103 ₂ , ..., 103 _N adds a frame bit or the like to the transmission signal and modulates the transmission signal.

Modulation board 103₀, 103₁, 103_Two,
…, 103_NThe transmission board 104₀, 104₁10,
Four_Two, ..., 104_NAre connected to each other, and the transmission board 104
₀, 104 ₁, 104_Two, ..., 104_NIs a modulated signal
Signal is converted into a transmission frequency and wirelessly transmitted. Furthermore
In addition, on the transmission side of the line switching device of the wireless transmission device
A control panel 110 is provided, and the sending end switching control panel 110 is
First wireless line, active second wireless line, ..., Active Nth wireless line
The input signal of the deteriorated working wireless line out of the
The backup wireless line is distributed to the backup wireless line and the standby wireless line.
Signal from the pilot signal to the signal of the working radio line
The sending end switching device 101 is controlled so as to be changed. In addition,
The sending end switching control panel 110 receives the data transmitted by the opposite device.
The receiving end switching control panel 114, which will be described later on the receiving side, detects line deterioration.
The signal of the corresponding working wireless line is predicted using the line deterioration information.
It forms the signal to be distributed to the radio line.

Further, a pilot signal generation board 111 is provided on the transmission side of the line switching device of the wireless transmission device, and the pilot signal generation plate 111 forms the pilot signal to the standby wireless line, and the sending end switching device 101. and outputs to the transmission signal processing board 102 ₀ spare radio channel through. In the normal state, the pilot signal is passed through the backup radio line to check the quality of the backup radio line, but when the working radio line deteriorates,
Instead of the pilot signal, the signal of the corresponding working radio line is passed through the backup radio line. Further, the transmission side of the line switching device of the wireless transmission device has a synchronous clock supply board 112.
The synchronization clock supply board 112 generates a synchronization clock for generating a radio frame (frame pulse FP), and the transmission signal processing boards 102 ₀ , 102 ₁ , 10
2 _2, ..., and supplies each of the 102 _N.

Next, on the receiving side of the line switching device of the wireless transmission device, receiving boards 105 ₀ , 105 ₁ , 105 ₂ , ..., 10 are provided.
5 _N are provided, and the receiving boards 105 ₀ , 105 ₁ , 10
5 ₂ , ..., 105 _N are transmission signal processing boards 102 ₀ , 102
₁ , 102 ₂ , ..., 102 _N , respectively, receive the transmission signals wirelessly transmitted, and perform frequency conversion from the reception frequency to the modulation frequency.

Receiving board 105₀, 105₁, 105_Two,
…, 105_NDemodulation board 106₀, 106₁10,
6_Two, ..., 106_NAre connected to each other, and the demodulation board 106
₀, 106 ₁, 106_Two, ..., 106_NDemodulates the modulated signal
Data signal (DATA), clock signal (CLK)
Demodulate each. Demodulation board 106₀, 106₁, 106_Two,
…, 106_NThe frame synchronization board 107₀, 107₁,
107_Two, ..., 107_NEach connected, frame
Synchronous board 107₀, 107₁, 107_Two, ..., 107_NIs
Frame bit is detected from demodulated signal and synchronization is judged
And outputs the signal for which synchronization has been established.

Frame synchronization boards 107 ₀ , 107 ₁ , 10
7 ₂ , ..., 107 _N for the synchronous switching boards 108 ₀ , 10
_{8 1, 108 2, ...,} 108 N are respectively connected, the synchronization switch board _{108 0, 108 1, 108 2} , ..., 108 N
Is a frame synchronization board 107 for the working wireless line and the standby wireless line.
₀ , 107 ₁ , 107 ₂ , ..., 107 _N are used to synchronously establish signals from the active wireless line to the standby wireless line or the standby wireless line to the active state by the control signal of the receiving end switching control panel 114 without interruption. Switch to a wireless line.

Synchronous switching board 108₁, 108_Two, ... 10
8_NInterface board 109₁, 109_Two, ... 1
09_NConnected to the interface board 109₁, 109
_Two, ..., 109_NOutputs the received signal. In addition, wireless
The receiving end switching control panel 1 is provided on the receiving side of the line switching device of the transmission device.
14 is provided, and the receiving end switching control panel 114 is the same as the frame.
Term 107₁, 107_Two, ..., 107_NMonitor the output of
Then, when the working wireless line deteriorates, the corresponding synchronous switching board 1
08 ₁, 108_Two, ..., 108_NAgainst the working radio times
Line frame synchronization board 107₁, 107_Two, ..., 107_N
Is a frame synchronization board 107 for a spare wireless line.₀Switch to
It The receiving end switching control panel 114 provided on the receiving side is a frame
Synchronous board 107₀, 107 ₁, 107_Two, ..., 107_N
If the current wireless line deteriorates by monitoring the line information of
Using the opposite device, the line deterioration information of the working wireless line
It is sent to the sending end switching control panel 110 on the sending side. Further switching the sending end
The control panel 110 uses the received line deterioration information to determine the transmission end switching device.
101 to control the sending end control signal and the receiving end switching control on the receiving side.
Send to board 114. The receiving end switching control panel 114 has a sending end control signal.
Switching board 108 of the working wireless line which has deteriorated after receiving the signal
Performs non-instantaneous interruption switching control of.

FIG. 7 shows the frame synchronization board 107 in FIG.
₀ , 107 ₁ , 107 ₂ , ..., 107 _N is a block diagram showing a schematic configuration of a synchronization establishment system of a line switching device provided in each.

Frame synchronization boards 107 ₀ , 107 ₁ , 10
7 _2, ..., 107 to _N respectively provided output data generation circuit 203, the output data generation circuit 203 demodulates Release _{106 0,} 106 _1, 106 2, ..., from 106 _N,
Data signal a (DATAa), clock signal b (CLK
b) is input respectively, DATAa excluding frame bits is generated in the case of synchronization, DATAa having a value of "1" is generated in the case of asynchronous, and is output to the synchronous switching board 108 together with CLKb.

The hunting circuit 201 is connected to the input side of the output data generation circuit 203, and the hunting circuit 201 is connected.
Inputs DATAa and CLKb to detect a frame bit and a synchronization determination. When the standby radio line selects the pilot signal, the hunting circuit 201
A frame bit included in DATAa is detected, a frame bit detection signal j is output, and a synchronization determination signal d for performing synchronization determination is output.

The hunting circuit 201 outputs a synchronization determination signal d to the output data generation circuit 203, and the synchronization determination signal d is used by the output data generation circuit 203 to generate DATAa. On the output side of the hunting circuit 201,
The frame counter circuit 202 is connected, and the frame counter circuit 202 inputs the frame bit detection signal j, the synchronization determination signal d, and CLKb from the hunting circuit 201, and when the synchronization determination signal d is a synchronization signal using CLKb. , The frame counter value c is set to "1" at the head position of the frame bit, and the frame length is sequentially counted up to "L", the frame count value c is returned to "1", and counting and counting are performed again.

When the synchronization determination signal d is an asynchronous signal,
When the frame counter value c becomes "L" and the frame counter value c is next set to "1", the count is masked and the position of "1" of the frame counter value c is moved. The frame counter value c of the frame counter circuit 202 is output to the hunting circuit 201. In this way, frame hunting synchronization is performed in the frame synchronization boards 107 ₀ , 107 ₁ , 107 ₂ , ..., 107 _N.

FIG. 8 is a time chart for explaining the operation of the frame synchronization board of the standby radio line and the working radio line in FIG. 7 when frame synchronization is established. In the case of the frame synchronization state, the figure (a) shows how the frame synchronizing board of the standby radio circuit processes the pilot signal, and the figure (b) shows that the frame synchronizing board of the working radio circuit processes the signal of the working radio circuit. Show the situation.

As shown in the figure, the data signal a (DAT
Aa) has a frame length of L bits (frame bits 8 bits (F bits) + data P (DP) bits). Clock signal a (C of data signal a (DATAa)
LKa) is a frame pulse (FP) i of the wireless transmission device.
Is in sync with. When the frame synchronization is established, the head position of the frame bit of the data signal a and the head position of the frame counter value c of the frame counter circuit 202 match.

As shown in FIG. 4A, the head position F0 of the frame bit in the data signal a of the spare radio circuit coincides with the radio frame (frame pulse FP) i. On the other hand, as shown in (b) and (c) of this figure, the head position F0 of the frame bit in the signal of the working first wireless line, the working second wireless line, etc. is the wireless frame (frame pulse FP).
Does not necessarily match i.

By using the above-mentioned radio frame (frame pulse FP) i for synchronization, the head position of the frame bit can be easily obtained. Usually, as shown in the figure, there is a phase difference τ1, τ2, ... Between the pilot signal of the standby radio line and the signals of the working first radio line, the working second radio line, and the like. That is, while the frame counter value c of the standby radio line is "1", the frame counter values c of the working first radio line and the working second radio line are "L-7" and "L-4", respectively. Yes, there is a difference. If any of the working first wireless line to the working Nth wireless line is deteriorated, the receiving end switching control panel 114 notifies the sending end switching control panel 110 of the deterioration, and the signal of the standby wireless line is transmitted from the pilot signal. , The deteriorated signal of the working wireless line is switched as follows.

[0022] Figure 9, when the degradation there is a time chart for explaining the operation of the frame synchronization disc 107 ₀ spare radio channel in FIG. As shown in this figure, time t ′
At 0, when the DATAa of the standby radio line is switched from the pilot signal to, for example, the signal of the working 1 radio line, at the time t'1 when the next frame counter value c becomes "1", the DATAa "DP- The frame bit is detected from the position "7".

At time t'2 when the next frame counter value c becomes "1", a mismatch with the frame bit is detected, and the frame bit detection signal j is output as a non-detection signal from the hunting circuit 201 to the frame counter circuit 202. It At time t′3 after the lapse of the forward synchronization protection time, the synchronization determination signal d is output from the hunting circuit 201 to the frame counter circuit 202 as an asynchronous signal.

At time t'4 after the synchronization judgment signal d becomes an asynchronous signal, the frame counter circuit 202 counts up the frame counter value c from "1" to "L" and then stops the counter for one clock. , The position of “1” of the frame counter value c is shifted. This processing is performed by the frame bit head position and the frame counter circuit 2.
This is performed until the start position of the frame counter value c of 02 matches.

When the leading position of the frame bit and the leading position of the counter of the frame counter circuit 202 coincide with each other when the frame counter value c immediately before the time t'5 becomes "1", the frame is moved to the time t'5. The bit detection signal j is output as a detection signal from the hunting circuit 201 to the frame counter circuit 202. At time t′6 after the backward protection time of synchronization has elapsed, the synchronization determination signal d becomes a synchronization signal indicating a synchronization state. In this way, the frame synchronization board 1
In 07 _0, hunting synchronization frame is made to switch. Therefore, the out-of-synchronization detection time and the synchronization time are required, so that it takes time for the working first wireless line to become error-free (same as the signal of the working wireless line) in the backup wireless line.

[0026]

However, in the system for establishing synchronization of the line switching device of the wireless transmission device, when the working wireless line is deteriorated and the signal of the protection wireless line is switched from the pilot signal to the signal of the working wireless circuit. However, there is a problem in that it takes time to synchronize the backup wireless line because synchronization is lost. The reason is that the frame phase of the pilot signal of the standby radio line and the frame phase of the signal of the working radio line are not the same as shown in FIG.

As shown in FIG. 9, at time t'0,
When the signal of the standby radio line is switched from the pilot signal to the signal of the working one radio line, at the time t′1 when the frame counter value c becomes “1” next, the hunting circuit 201 causes the hunting circuit 201 to switch the working one radio line. DATAa that becomes a signal
The frame bit detection result starting from the position of “DL-7” is determined to be frame pattern mismatch at time t′2 when the frame counter circuit 202 becomes “1” next time, and time t ′ after the forward protection time has elapsed. At 3, the synchronization determination signal d becomes an asynchronous signal.

Next, at time t'4 when the frame counter value c becomes "1", the counting up of the frame counter value c is stopped, and the hunting operation for shifting the "1" position of the frame counter value c is performed. When the frame bit is detected at 5, the synchronization state is realized at time t'6 after the backward protection time has elapsed. . Therefore, the out-of-synchronization detection time and the synchronization time are required, so that it takes time for the working first wireless line to become error-free (same as the signal of the working wireless line) in the backup wireless line.

Furthermore, the synchronization establishment system line switching unit of the wireless transmission device, unnecessary alarm when out-of-synchronization occurrence of a frame synchronization disc 107 ₀ there is a problem that occurs. The reason is that an out-of-sync alarm is generated when out-of-sync of the frame sync board 107 ₀ occurs, and the alarm is recovered after the synchronization of the frame sync board 107 ₀ is established.

This is because this alarm is not an alarm caused by deterioration of the line quality of the wireless line but an alarm caused by loss of synchronization. Therefore, in view of the above-mentioned problems, the present invention prevents line out-of-sync at the time of switching between the working wireless line and the spare wireless line, prevents unnecessary alarms from occurring, and realizes high-speed switching. An object is to provide a system for establishing synchronization of devices.

[0031]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention synchronizes a line switching device for switching one of a plurality of working radio lines to a standby radio line in which a pilot signal is normally transmitted. In the establishment system, the working radio circuit, a frame synchronization unit for detecting the position of the head of the frame bit for each of the protection radio lines and performing hunting synchronization of the frame, respectively, and the communication between the working radio line and the protection radio line. A position information storage unit that stores in advance the position information at the beginning of a frame bit, and refers to the position information in the position information storage unit when switching the signal of the standby radio circuit from the pilot signal to the signal of the working radio line. , The frame bit head of the pilot signal of the protection radio line is set to the working radio frequency with respect to the frame synchronization unit of the protection radio line. Providing synchronization establishment system of the line switching device characterized by the and a frame bit head switching to switch the sync interchanged positions to the synchronization of the signal. By this means, it is possible to prevent out-of-synchronization when switching the signal of the spare wireless line from the pilot signal to the signal of the working wireless line, so that high-speed switching is possible and unnecessary alarms can be prevented.

Preferably, the head position of the frame bit of the protection radio line is matched with the frame pulse of the line switching device so that the head position of the frame bit of the working radio line is determined from the frame pulse of the line switching device. It is represented by the position. By using the frame pulse of the line switching device like this means, it becomes possible to easily obtain the head position of the frame bit for the plurality of working wireless lines.

Preferably, in the switching of the head of the frame bit by the switching synchronization unit, after switching the signal of the protection radio line from the pilot signal to the signal of the working radio line, the signal of the protection radio line is switched. It is also performed when the signal of the working radio line is switched to the original pilot signal. By this means, even if the active wireless line is continuously switched due to fading or the like, it is possible to switch to the standby wireless line at high speed.

Preferably, the position information of the head of the frame bit between the plurality of active wireless lines and the standby wireless line stored in the position information storage unit is replaced with a pilot signal in advance before the operation starts, The respective signals of the plurality of active radio circuits are distributed to the standby radio line, and are sequentially obtained by hunting synchronization of frames in the frame synchronization unit of the standby radio line.

By this means, the position information is prepared in advance. Preferably, the line information received by a plurality of the working wireless lines is monitored, and when the signal of the working wireless line is deteriorated, the line deterioration information of the corresponding working wireless line is sent to the transmitting side, and the input signal of the working wireless line is sent. Distribute to the working radio line and the protection radio line, switch the signal of the protection radio line from the pilot signal to the signal of the working radio line, and switch the head position of the frame bit to the switching synchronization unit to switch synchronization. To perform. By this means, when the working wireless line deteriorates, the standby wireless line can be used without losing synchronization.

Further, according to the present invention, one of a plurality of working radio lines is used as a standby radio line through which a pilot signal is normally transmitted.
In the method for establishing synchronization of a line switching device for switching between two, the step of detecting the position of the head of a frame bit for each of the working wireless circuit and the standby wireless circuit and performing hunting synchronization of the frame, respectively, the working wireless circuit and the working wireless circuit A step of pre-storing the position information of the head of the frame bit with respect to a spare wireless line; and a position of the position information storage part when switching the signal of the spare wireless circuit from a pilot signal to a signal of the working wireless line. Referring to the information, and switching the synchronization by causing the frame synchronization unit of the standby radio line to replace the position of the frame bit head of the pilot signal of the standby radio line with the frame bit head of the signal of the working radio line. There is provided a synchronization establishing system for a line switching device, characterized by comprising:

By this means, as in the case of the above-mentioned invention, it is possible to prevent out-of-synchronization when switching the signal of the standby radio line from the signal of the pilot radio signal to the signal of the working radio line. It is possible to prevent the occurrence.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a line switching device of a wireless transmission device according to the present invention. As shown in the figure, as compared with FIG. 6, the frame synchronization board 107 of the standby radio line on the receiving side of the radio transmission apparatus is used.
A ₀ is different, and a synchronous clock supply board 113 is provided.

The synchronous clock supply board 113 generates the same device FPi as the synchronous clock supply board 112 on the transmitting side,
It is connected to the frame synchronization board 107A ₀ and supplies the device FPi. Further, the frame synchronizing board 107A ₀ is supplied with the line switching information h from the receiving end switching control board 114.

FIG. 2 is a block diagram showing a schematic configuration of the synchronization establishing system of the line switching device provided in the frame synchronization board 107A ₀ of the spare radio line in FIG. An output data generation circuit 303 is provided on the frame synchronization board 107A ₀ , and the output data generation circuit 303 operates on the demodulation board 106 _0.
From data signal a (DATAa), clock signal b
(CLKb) is input, DATAa excluding frame bits is generated in the case of synchronization, and DATAa with all “1” values is generated in the case of asynchronous.
It outputs to the synchronous switching board 108 with b.

A hunting circuit 301 is connected to the input side of the output data generation circuit 303, and the hunting circuit 301 is connected.
Inputs DATAa and CLKb, and outputs a frame bit detection signal j by using a frame counter value c of a frame counter circuit 302 described later for the frame bit in DATAa. That is, the hunting circuit 301 detects a frame bit from a position where the value of the frame counter value c becomes "1", and when the frame counter value c becomes "1" next time, if the frame bit matches. The detection signal is output as the frame bit detection signal j, and when the frame bits do not match, the non-detection signal is output as the frame bit detection signal j.

Further, the hunting circuit 301 outputs a synchronization determination signal d which is synchronous when the frame bit detection signal j is in the plural frame detection state and is asynchronous when it is the plural frame non-detection state. A frame counter circuit 302 is connected to the hunting circuit 301, and the frame counter circuit 302 inputs the frame bit detection signal j and the synchronization determination signal d from the hunting circuit 301.

The frame counter circuit 302 uses CLKb from the frame counter value c from "1" to the frame length "L" at the head position of the frame bit when the frame bit detection signal j from the hunting circuit 301 is in the detected state. The frame counter value c is counted up again at the head position of the frame bit and the frame counter value c is counted up to "1". When the frame bit detection signal j is in the non-detection state, the frame counter value c becomes "L", and then the frame counter value When the value c is set to "1", the count is masked and the position of "1" of the frame counter value c is moved.

A holding circuit 305 is connected to the output side of the frame counter circuit 302, the holding circuit 305 inputs the frame counter value c from the frame counter circuit 302, and further, from the synchronous clock supply board 113 to the device FPi.
Enter. Further, the frame synchronization board 107A ₀ is provided with a line selection judgment circuit 306, and the line selection judgment circuit 3
The line switching information 06 is input from the receiving end switching control panel 114.

For example, when the working Kth wireless line (K = 1 to N) is deteriorated, the line selection determining circuit 306 causes the sending end switching control panel 110 to input the input signal of the corresponding working Kth wireless line to the working Kth wireless line. A line selection signal g indicating that the working Kth wireless line has been selected from the line switching information h, which is distributed to the wireless line and the standby wireless line and switches the signal of the standby wireless line from the pilot signal to the signal of the active wireless line. Similarly, the counter setting signal k is set and output.

The frame counter circuit 302 receives the counter setting signal k, controls the change of the counter value by the counter setting signal, and outputs the setting change signal 1 after the change. Upon receiving the setting change signal 1 from the frame counter circuit 302, the line selection determination circuit 306 changes the counter setting signal k to non-setting.

The hunting circuit 301 includes a memory circuit 304.
Are connected, and the memory circuit 304 inputs the synchronization determination signal d from the hunting circuit 301. Further, the memory circuit 304 is connected to the holding circuit 305 and inputs position information e from the holding circuit 305. Further, the memory circuit 304 is connected to the line selection determination circuit 306, and the line selection signal g is input from the line selection determination circuit 306.

FIG. 3 is a timing chart for explaining an operation example in which the position information e is stored in advance in the storage circuit 304 in FIG. Before starting the operation, temporarily stop the input of the signal of the pilot signal generation panel 111 to the standby radio line,
The signal of the working first wireless line is distributed to the standby wireless line, and the holding circuit 305 receives the frame counter value c input from the frame counter circuit 302 at the position of the device FPi at time t as shown in the figure. For example, “L-7” is held as the position information e1, and the storage circuit 304 holds the holding circuit 3.
This is input from 05, and the position information e of the working first wireless line e
It is stored as 1. That is, the position information e1 of the working first wireless line is information on the count value from the start position of the frame bit relating to the pilot signal of the protection wireless line to the starting position of the frame bit relating to the signal of the working first wireless line.

Next, similarly, the active second wireless line is distributed to the standby wireless line, and the holding circuit 305 causes the frame counter circuit 302 to move from the frame counter circuit 302 at the position of the device FPi at time t ', as shown in the figure. The storage circuit 304 holds the input frame counter value c, for example, “L-4”, and the storage circuit 304 stores it in the storage circuit 3.
This is input from 05 and stored as position information of the second working radio line.

Similarly, the storage circuit 304 stores the position information e3 to eN of the active third wireless circuit to the active Nth wireless circuit.
Memorize Further, the position information e1 to eN correspond to the phase differences τ1 to τN in FIG. It should be noted that the storage circuit 304 retains the above-mentioned stored value even when the line deterioration of a certain working Kth wireless line (K = 1 to N) is restored and the pilot signal is transmitted to the standby wireless line in the normal state. Keep it. If it is difficult to obtain location information on a regular basis, or if the degree of use of the working wireless line is high, it is possible to obtain location information by using the time of switching due to deterioration or maintenance of the working wireless line. become.

FIG. 4 is a timing chart for explaining an operation example when the standby radio line is switched to the working Kth radio line at the time of deterioration. As shown in the figure, at time t0, the backup radio line is switched from the pilot signal to the signal of the working Kth radio line, so that the line switching information h of the receiving end switching control panel 114 is switched to the working Kth radio line. Make a request. At this time, DATAa also changes from "F5" of the pilot signal to "DP-2" of the signal of the working Kth wireless circuit.

The line selection judgment circuit 306 uses the line switching information h
It is determined that the pilot signal has been changed to the signal of the working Kth wireless line by means of the line selection signal g indicating that the signal of the working Nth wireless line is being used in the standby wireless line.
Is output to the memory circuit 304, the counter setting signal k is changed to the setting, and output to the frame counter circuit 302. The storage circuit 304 sets the storage value of the working Kth wireless circuit indicated by the line selection signal g as the output value f, and the frame counter circuit 30.
Output to 2.

At the time t2 when the frame counter value c after 2 frames from the time t0 becomes "1", the hunting circuit 3
01 sets the frame bit detection signal j to a non-detection signal as the detection result of the frame bit having “DP-7” of DETAa from the time t1 as the head of the frame bit.
When the counter setting signal k is set and the frame bit detection signal j is not detected, the frame counter circuit 302 sets the device FPi to CL at the “L (LOW)” level.
At time t2 when Kb falls, the value of the frame counter value c is changed to the value of the stored value f, and then the setting change signal 1 is set and output to the line selection determination circuit 306.

The line selection discrimination circuit 306 changes the counter setting to non-setting by setting the setting change signal l. The frame counter value c changed to the stored value f is counted up, and at the time t3 when the next frame counter value c becomes "1", DATAa becomes the leading value of the frame bit of the working Kth wireless line, At time t4 when the next frame counter value c becomes "1", the frame bit detection signal j becomes a detection signal.

Instead of synchronizing by frame hunting as in the conventional case, the leading position of the frame counter value of the pilot signal is changed to the stored frame counter value of the working Kth wireless line to establish the established hunting synchronization. By maintaining the above, it becomes possible to switch to the working Kth wireless line without losing synchronization. FIG. 5 is a modification of FIG. 4, and is a timing chart for explaining an example of storing the position information of the pilot signal of the backup radio line. In the steady state in which the pilot signal is selected as the pilot radio signal as well as the active first radio circuit to the active N radio circuit, the position information "1" of the pilot signal is obtained at time t ". May be stored in the storage circuit 304.

When the deterioration of the working Kth radio circuit is restored and the protection radio line is switched from the working Kth radio circuit to the pilot signal, the line selection signal g is changed to the signal of the working Kth radio circuit and the protection radio by the operation of FIG. Since the operation is the same as that for exchanging the signal on the line, it is possible to switch to the pilot signal without causing synchronization loss. The advantage of this embodiment is that there is no need to wait for resynchronization as in the conventional case.
Even when the standby radio line is switched to the pilot signal (switching back from the active radio line), it is possible to switch without synchronization, so even if the active radio line is continuously switched due to fading, etc. , It becomes possible to switch the standby radio line without interruption without interruption.

[0057]

As described above, according to the present invention,
The position information of the head of the frame bit between the working wireless line and the standby wireless line is stored in advance, and the position information in the position information storage unit is stored when the signal of the standby wireless circuit is switched from the pilot signal to the signal of the working wireless line. With reference to the frame synchronization part of the protection wireless line, the position of the head of the pilot bit of the pilot signal of the protection wireless line is replaced with the position of the head of the frame bit of the signal of the working wireless line to switch the synchronization. Even when switching to the standby line occurs at the time of maintenance or inspection, the line can be switched at high speed.

This is because, even if the switching to the backup radio line occurs, it is no longer necessary to hunt the frame and synchronize again after the loss of synchronization as in the conventional case.
Therefore, the out-of-synchronization detection time and the synchronization time are eliminated, so that high-speed synchronization can be achieved. Furthermore, it has become possible to prevent the generation of unnecessary alarms. This is because conventionally, an out-of-sync alarm is generated due to the out-of-sync, but in the present invention, since the out-of-sync alarm does not occur, an unnecessary alarm does not occur.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a line switching device of a wireless transmission device according to the present invention.

FIG. 2 is a frame synchronization board 1 of the standby radio line in FIG.
It is a block diagram showing a schematic configuration of a synchronization establishment system of the line switching device provided in 07A _0.

FIG. 3 is a timing chart illustrating an operation example in which position information e is stored in advance in a storage circuit 304 in FIG.

FIG. 4 is a timing chart for explaining an operation example when switching a backup radio line to a working K-th radio line at the time of deterioration.

5 is a modification of FIG. 4, and is a timing chart explaining an example of storing position information of a pilot signal of a backup radio line.

FIG. 6 is a block diagram showing a schematic configuration of a line switching device of a wireless transmission device which is a premise of the present invention.

FIG. 7 is a diagram showing the frame synchronous boards 107 ₀ and 107 in FIG. 6;
₁ is a block diagram showing a schematic configuration of a synchronization establishment system of a line switching device provided in each of 107 ₂ , ..., 107 _N.

8 is a time chart for explaining the operation of the frame synchronization board of the standby wireless line and the working wireless line in FIG. 7 when frame synchronization is established.

If the [9] degradation there is a time chart for explaining the operation of the frame synchronization disc 107 ₀ spare radio channel in FIG.

[Explanation of symbols]

100 _{1 to N} , 109 _{1 to N} ... Interface board 101 ... Sending end switch 102 0 to _N ... Transmission signal processing board 103 0 to _N ... Modulation board 104 0 to _N ... Transmitting board 105 _{0 to N} ... Receiving board 1060 _{to N ...} demodulation board ₁₀₇ 1 to N, 107A 0 _... frame synchronization Release 108 _{1 to N ...} synchronous switching board 110 ... feed edge switch control board 111 ... pilot signal generating board 112, 113 ... synchronous clock supply board 114 ... receiving end switching Control panel 301 ... Hunting circuit 302 ... Frame counter circuit 303 ... Output data generation circuit 304 ... Storage circuit 305 ... Holding circuit 306 ... Line selection determination circuit

Continuation of front page (56) Reference JP-A-5-244127 (JP, A) JP-A-2-43840 (JP, A) JP-A-10-126398 (JP, A) JP-A-62-137934 (JP , A) JP 10-224329 (JP, A) JP 10-285081 (JP, A) JP 7-221724 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) H04L 7/08 H04B 1/74 H04L 29/14

Claims (6)

(57) [Claims] 1. A synchronization establishment system of a line switching device for switching one of a plurality of working wireless lines to a standby wireless line to which a pilot signal is normally transmitted, wherein a frame is provided for each of the working wireless circuit and the standby wireless line. A frame synchronization unit that detects the position of the start of the bit and performs hunting synchronization of the frame, and a position information storage unit that stores in advance the position information of the start of the frame bit between the working wireless line and the standby wireless line. And when switching the signal of the standby radio circuit from the pilot signal to the signal of the working radio line, referring to the position information of the position information storage unit, the standby radio to the frame synchronization unit of the standby radio line. Synchronize by switching the position of the frame bit head of the pilot signal of the line to the frame bit head of the signal of the working wireless line A synchronization establishing system for a line switching device, comprising: 2. The position of the head of the frame bit of the protection radio line is matched with the frame pulse of the line switching device so that the position of the head of the frame bit of the working radio line is changed from the frame pulse of the line switching device. The system for establishing synchronization of a line switching device according to claim 1, wherein the system is represented by a position. 3. The switching of the head of the frame bit by the switching synchronization unit is performed by switching the signal of the backup radio line from the pilot signal to the signal of the working radio line, and then switching the signal of the backup radio line. 2. The synchronization establishing system for a line switching device according to claim 1, wherein the synchronization establishing system is also performed when the signal of the working radio line is switched to the original pilot signal. 4. The position information at the beginning of the frame bit between the working radio line and the protection radio line stored in the position information storage unit is replaced with a pilot signal in advance before the operation starts, and the working radio line is replaced. 2. The line switching device according to claim 1, wherein each signal of the circuit is distributed to the backup radio line and sequentially obtained by hunting synchronization of frames in the frame synchronization unit of the backup radio line. Synchronization establishment system. 5. The line information received by a plurality of the working wireless lines is monitored, and when the signal of the working wireless line deteriorates,
The line deterioration information of the corresponding working wireless line is sent to the transmitting side, the input signal of the working wireless line is distributed to the working wireless line and the standby wireless line, and the signal of the standby wireless line is transmitted from the pilot signal to the working wireless line. 2. The synchronization establishment of the line switching device according to claim 1, wherein switching to a signal is performed, and the switching synchronization unit switches the start position of the frame bit to switch synchronization. system. 6. A method for establishing synchronization of a line switching device for switching one of a plurality of active wireless lines to a standby wireless line through which a pilot signal is normally transmitted, wherein a frame is provided for each of the active wireless circuit and the standby wireless line. Detecting the position of the bit head and performing hunting synchronization of the frame respectively; pre-storing the position information of the frame bit head between the working radio line and the spare radio line; When switching the signal from the pilot signal to the signal of the working wireless line, the frame bit of the pilot signal of the standby wireless line is referred to the frame synchronization unit of the standby wireless line by referring to the position information of the position information storage unit. Switching the synchronization by switching the position to the beginning of the frame bit of the signal of the working wireless line. A method for establishing synchronization of a line switching device, comprising: