JPH07321711A - Line changeover system in radio communication system - Google Patents

Abstract

PURPOSE:To reduce the scale of equipment configuration and to use the frequency effectively by reducing the number of standby channels used to select plural active channels whose delay time differs from each other. CONSTITUTION:When any of plural active channels 10, 20 is selected and it is switched to a standby line 50, in order to avoid that uninterruptible changeover by an uninterruptible changeover device 26 is disable because of a delay time difference between a delay time in the selected active channel 20 and P delay time of the standby channel 50, the delay time difference is adjusted by a delay adjustment circuit 27 so as to attain uninterruptible changeover by eliminating a delay time difference between both the channels. Thus, it is possible to switch uninterruptibly the plural channels into one standby channel, the equipment configuration space is reduced and the effective utilization of frequency is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line switching system for switching between a working line and a protection line in a digital wireless communication system, and in particular, a line capable of switching without interruption between N types of transmission systems having different delay times. Regarding switching method.

[0002]

2. Description of the Related Art The line switching system by working / standby line is
It is known by various documents. For example, “Microwave Communications” by Moruji Kuwahara, The Telecommunications Association, P.
There are 152 to 156 and a line automatic switching system. Further, as a technique for switching the working / protection line without interruption in order to prevent a signal loss when switching from the working line to the protection line, for example, there is a technique described in Japanese Patent Laid-Open No. 56-153863.

An example of a conventional line switching system of this type is shown in FIG.
Is shown in the block diagram. In this example, the first working line 1
0 and the second working line 20 are replaced by protection lines 50 and 60, respectively.
This is an example of a switchable configuration. First working line 10
Is a transmission system including a first modulator 11 and a first transmitter 12, and
The reception system includes a first receiver 13 and a first demodulator 14, and the first working signal passes through a first transmission end switcher 15, a first modulator 11, a first transmitter 12, and a first transmitter 12. 1 receiver 1
3. The signal is regenerated through the first demodulator 14 and passed through the first non-interruption switching device 16 to be provided as a first working signal output to the carrier-end device in the subsequent stage. Further, the first working line 10 is provided with a first protection line 50.
The first modulator 51, the first transmitter 52, the first receiver 53, and the first demodulator 54 of the same standard as 1 working line 1
0 connected in parallel.

The second working line 20 has the same configuration except that the transmission system is different, and includes a second modulator 21, a second transmitter 22, a second receiver 23, and a second demodulator 24. , The second working signal passes through the second sending end switching device 25, is then reproduced through them, and passes through the second hitless switching device 26 to be output as the second working signal. Also for this second working line 20, a second backup line 60I configured according to the same standard as the second working line 20 is provided with a second sending end switch 25 and a second
It is connected in parallel to the second working line 20 by the hitless switch 26.

Here, the first and second working lines 1
Different frequency bands are used for 0, 20 and protection lines 50, 60, respectively. Further, the transmission method of the first working line 10 and the protection line 50 is different from the transmission method of the second working line 20 and the protection line 60. Therefore, the delay caused when the signal is transmitted in each line. The time is different between the first and second working lines 10 and 20.

The first and second protection lines 50,
Reference numeral 60 designates first and second pilot signal generators 101, 1 used for monitoring the quality of the protection line, respectively.
03 and the pilot signal detectors 102 and 104 are connected. The quality of each of the first and second working lines 10 and 20 and the protection lines 50 and 60 is monitored by the line monitoring device 100. Based on the monitoring result, the transmission end switching devices 15 and 25 are not identified. The instantaneous interruption switching devices 16 and 26 are controlled.

In this wireless communication system, when the line quality of the first working line 10 is deteriorated due to a propagation failure or a device failure, the line monitoring apparatus 100 detects this, and based on the detection result, The connection mode of the first end switching device 15 and the first hitless switching device 16 is switched. As a result, the first working line 10 is switched to the first protection line 50, and the first working signal is passed from the first working line 10 to the first protection line 50. That is, the first working signal is reproduced through the first modulator 51, the first transmitter 52, the first receiver 53, and the first demodulator 54 of the first protection line 50, and the first working signal is reproduced. It is output from the hitless switching device 16. And when switching lines here,
Since the first working line 10 and the protection line 50 are configured as the same transmission system, there is no delay time difference between the two lines, and the first non-interruption switch 16 enables switching without non-interruption. Done.

When the line quality of the second working line 20 deteriorates, the second working line 20 is switched to the second protection line 60. That is, the second working signal is the second modulator 61 of the second protection line 60, the second transmitter 6
2, reproduced via the second receiver 63 and the second demodulator 64, and output from the second hitless switch 26. Since the second working line 20 and the second protection line 60 have the same transmission method as the line switching here, the second non-interruption switch 26
You can switch without interruption.

[0009]

In the line switching system in the wireless communication system having such a configuration, the line quality of the working line is deteriorated due to a propagation failure or equipment failure, and the switching between the working line and the protection line is interrupted without interruption. In order to do so, it is necessary to perform the same transmission method, that is, between the working line and the protection line having the same delay time. Therefore, in the case shown in FIG. 3, the transmission method is different between the first working line 10 and the second working line 20, so that the first working line 10 is the first protection line of the same transmission system. 50, and the second working line 20 is the second protection line 60 of the same transmission method as this.
Need to switch to.

Therefore, in the conventional line switching system, it is necessary to provide a backup line having the same delay time as each of the working lines of the different transmission systems. Therefore, in the above example, two different backup lines 50, 60 is required. For this reason, there is a problem that the device configuration scale for executing the line switching becomes large and the frequency utilization efficiency deteriorates by the number of the backup lines.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a line switching system capable of reducing the number of protection lines and enabling non-instantaneous switching at the time of line switching. Another object of the present invention is to provide a line switching system in which the device configuration scale is reduced by reducing the number of backup lines and the frequency utilization efficiency is improved.

[0012]

The line switching system of the present invention has a plurality of working lines and one or more protection lines, each of which has a different delay time in a transmission line of wireless communication, and a part of the working line. In the line switching system configured to switch to a protection line, a plurality of working lines are selectively switchable to the same protection line, and a working line selected between each working line and the protection line It is characterized by comprising a delay adjusting circuit for giving a delay amount corresponding to a delay time difference between the line and the protection line.

For example, a plurality of working lines, one protection line, a transmission end switch for selecting a signal input to the input end of each working line to switch to the protection line, and selecting an output signal of the protection line A non-interruption switching device that switches to the output end of the working line that has been selected, and a delay adjustment circuit that is inserted between the protection line and the selected working line, and the delay time in the working line that has been switched to the protection line, The delay adjustment circuit adjusts the delay time difference from the delay time in the protection line. Further, it has a line monitoring device for monitoring the line quality in each of a plurality of working lines and one or more protection lines, and the line monitoring device controls the sending end switch and the non-interruption switch and is selected. The working line is switched to the protection line.

[0014]

When any one of a plurality of working lines is selected and switched to the protection line, it is impossible to switch without interruption due to the delay time difference between the delay time of the selected working line and the delay time of the protection line. Therefore, by adjusting this delay time difference in the delay adjusting circuit and eliminating the delay time difference in both lines, it is possible to achieve no interruption during switching.

[0015]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing an example of a wireless communication system to which the line switching system of the present invention is applied. In this example, the first working line 10 and the second working line 20 of N types (N = 2) of different transmission systems can be switched to the same protection line 50. The first working line 10 is the first
It is composed of a transmission system including the modulator 11 and the first transmitter 12, and a reception system including the first receiver 13 and the first demodulator 14, and the first working signal is generated by the first transmission end switcher 15. Street, first
Reproduced through the modulator 11, the first transmitter 12, the first receiver 13, and the first demodulator 14, and passes through the first no-stop switcher 16 to be output as the first working signal to the downstream end equipment or the like. Given.

The second working line 20 includes a transmission system including a second modulator 21 and a second transmitter 22, a second receiver 23 and a second transmission line.
And a receiving system including a demodulator 24. The second working signal passes through the second sending end switch 25, and then the second modulator 2
1, second transmitter 22, second receiver 23, second demodulator 24
And is reproduced through the second non-instantaneous-interruption switch 26 to be the second working signal output.

Also, these first and second working lines 1
In contrast to 0 and 20, here, the transmission system including the modulator 51 and the transmitter 52 and the receiving system including the receiver 53 and the demodulator 54 are used as the same transmission system as the first working line. A backup line 50 is connected in parallel to the first working line 10 by a first sending end switch 15 and a first non-interrupting switch 16 provided in the first working line 10.

Here, the first and second working lines 1
0, 20 and the protection line 50 use different frequency bands. In addition, the first working line 10 and the protection line 50
The transmission method in is set so that its delay time is longer than that of the transmission method in the second working line 20. Although the second sending end switching device 25 and the first sending end switching device 15 are directly connected, the second uninterruptible switching device 26 and the first uninterruptible switching device 16 are connected to each other. A delay adjustment circuit 27 is interposed between the delay adjustment circuits 27. The delay amount of the delay adjustment circuit 27 is the delay time of the transmission method in the first working line 10 and the delay time of the transmission method in the second working line 20. Is set equal to the delay time difference between and. As the delay adjustment circuit 27, various known delay circuits are used,
The delay amount is preset by manual operation or the like.

The backup line 50 has a second and a first line.
The pilot signal generator 101 used for monitoring the quality of the protection line is connected via the transmission end switches 25 and 15 of the second transmission switch 26, and the second non-interruption switch 26 and the delay adjustment circuit 2 are connected.
The pilot signal detector 102 is connected via 7 and the first hitless switching device 16. The first and second working lines 10 and 20 and the protection line 50 are connected to the line monitoring device 10.
The quality of each line is monitored by 0, and the sending end switches 15 and 25 and the no-interruption switch 1 are monitored based on the monitoring result.
6, 26 are controlled.

According to this configuration, when the line quality of the first working line 10 is deteriorated due to a propagation failure or a device failure, the line monitoring apparatus 100 detects the deterioration, and based on the detection result, The connection mode of the first end switching device 15 and the first hitless switching device 16 is switched. As a result, the first working line 10 is switched to the protection line 50, and the first working signal is passed from the first working line 10 to the protection line 50. That is, the first working signal is the modulator 51, the transmitter 52, the receiver 53 of the protection line 50,
It is reproduced through the demodulator 54 and output from the first hitless switching device 16. And when switching lines here,
Since the first working line 10 and the protection line 30 are configured as the same transmission method, there is no delay time difference between the two lines, and the first non-interruption switch 16 enables switching without non-interruption. Done.

On the other hand, when the line quality of the second working line 20 is deteriorated, the second working line switching unit 25 switches the second working line 20 to the protection line 50. The second working signal is reproduced through the modulator 51, the transmitter 52, the receiver 53, and the demodulator 54 of the protection line 50. Then, after passing through the delay adjusting circuit 27, it is output from the second non-instantaneous interruption switch 26. Since the second working line 20 and the protection line 50 have different transmission methods at the time of line switching here,
The signal reproduced on the protection line 50 naturally differs from the signal reproduced on the second working line 20 in the amount of delay. However, the signals having the different delay amounts are passed through the delay adjusting circuit 27, where the delay amount is adjusted so as to be equal to that of the second working line 20, so that the signals reach the second hitless switch 26. The delay amounts become the same when they are performed. As a result, the second hitless switch 26 is switched without hitting.

Therefore, in this line switching method, only one protection line is required for switching the two working lines having different delay times, and no matter which working line is switched, non-instantaneous switching is possible. Therefore, it is possible to reduce the device configuration scale of the line switching system by the amount of the reduction of the protection line as compared with the conventional configuration, and it is possible to reduce the frequency assigned to the protection line and to effectively use the frequency. Become.

FIG. 2 is a block diagram of the second embodiment of the present invention, in which an example of working lines of different transmission systems with N = 4 is shown. The respective configurations of the first working line 10 to the fourth working line 40 are the same as the respective working lines of the first embodiment, and are not shown here. However,
Here, the transmission systems in the first to fourth working lines are different, and the delay times are different. The protection line 50 also has the same configuration as the protection line of the first embodiment, and has the same transmission method as the first working line 10.

The first working line 10, the second working line 10 and the protection line 50 have the same structure as in the first embodiment, and the third working line 30 and the fourth working line 4 are added to this.
0 is connected to the backup line 50 through the third sending end switch 35 and the third non-interruption switch 36, and the fourth sending end switch 45 and the fourth non-interruption switch 46, respectively. is doing. In addition, the third non-stop switch 36 and the first non-stop switch 16
A second delay adjustment circuit 37 is interposed between the first and second non-interruption switching devices 46 and 16 and a third delay adjustment circuit 47 is interposed between the second non-interruption switching device 46 and the first non-interruption switching device 16. Has been inserted. Here, the second delay adjusting circuit 37 is configured to give a delay amount corresponding to the delay time difference between the first working line 10 and the third working line 30, and the third delay adjusting circuit 37 It is configured to provide a delay amount corresponding to the delay time difference between the first working line 10 and the fourth working line 40.

Therefore, with this configuration, when the first working line 10 is switched to the protection line 50, there is no delay time difference between the two in the same transmission system, and therefore switching can be performed without interruption. Further, when the second working line 20 is switched to the backup line 50, the delay time difference between the second working line 20 and the backup line 50 is adjusted in the delay adjusting circuit 27, so that the line can be switched without interruption. . Similarly,
When switching the third working line 30 to the protection line 50, the delay time difference between the third working line 30 and the protection line 50 is adjusted in the second delay adjustment circuit 37, and when switching the fourth working line 40 to the protection line 50. The third delay adjusting circuit 47 adjusts the delay time difference between the third delay adjusting circuit 47 and the backup line 50, so that the lines can be switched without interruption.

In each of the above embodiments, the delay adjusting circuits 27, 37, 47 are fixedly set in advance in accordance with the delay time difference between the lines. Configured, obtain the timing signal from the signal on each line, measure the delay time difference between each line,
The delay amount in the variable delay adjustment circuit may be controlled based on the measurement result. In this case, only one variable delay adjustment circuit is provided on the line connected to the protection line, and if the delay amount of the variable delay adjustment circuit is controlled according to the delay time difference between the line switched to the protection line and the protection line, The delay adjustment circuit is not limited to the number of a plurality of working lines having different delay times and can be configured by one delay adjusting circuit.

Further, theoretically, the delay adjusting circuit can be inserted at the input end side of the working line and the protection line, but in practice, the delay adjusting circuit is made at the output end side of the transmission line. An example configuration will be taken.

[0028]

As described above, according to the present invention, a plurality of working lines are selectively switchable to the same protection line, and a working line selected between each working line and the protection line. Since it is equipped with a delay adjustment circuit that gives a delay amount corresponding to the delay time difference between the protection line and the protection line, when selecting one of the working lines and switching to the protection line, the delay time in the selected working line, By adjusting the delay time difference from the delay time in the protection line in the delay adjustment circuit and eliminating the delay time difference in both lines, no interruption during switching is possible.

Therefore, only one protection line is required to switch the working lines having different delay times, and the number of protection lines can be reduced as compared with the conventional configuration, and the device configuration scale of the line switching system can be reduced. In addition, it is possible to reduce the frequency assigned to the protection line and to effectively use the frequency. In particular, even if one protection line is provided for three or more working lines, each working line can be switched to the protection line without interruption, and the number of protection lines can be significantly reduced, resulting in a large device configuration scale. It is possible to achieve effective reduction and effective use of frequency.

Further, even when a line monitoring device for monitoring the line quality of each of the working line and the protection line is provided and the switching operation of the working line and the protection line is performed by this line monitoring device, the switching is not performed. It is possible to do it in a momentary interruption.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a first embodiment of a line switching system of the present invention.

FIG. 2 is a block diagram of a second embodiment of the present invention.

FIG. 3 is a block diagram showing an example of a conventionally proposed line switching system.

[Explanation of symbols]

 10 First Working Line 20 Second Working Line 30 Third Working Line 40 Fourth Working Line 50 Backup Line 15, 25, 35, 45 Sending End Switch 16, 26, 36, 46 Continuous Switching 27, 37, 47 Delay adjustment circuit

Claims (5)

[Claims] 1. A line switch having a plurality of working lines and one or more protection lines each having a different delay time in a transmission line of wireless communication, and configured to switch a part of the working lines to the protection line. In the system, the plurality of working lines are selectively switchable to the same protection line, and a delay time difference between the working line and the protection line selected between each working line and the protection line is supported. A line switching system in a wireless communication system, characterized by comprising a delay adjusting circuit for giving the amount of delay. 2. A plurality of working lines and one protection line,
A transmission end switching device that selects a signal input to the input end of each working line and switches to the protection line, and a non-interruption switching device that switches the output signal of the protection line to the output end of the selected working line And a delay adjustment circuit interposed between the protection line and the selected working line. 3. A hitless switching device is provided between each output end of the plurality of working lines and an output end of the protection line, and between the hitless switching device and the output end of the protection line. 3. The radio communication according to claim 2, wherein a delay adjustment circuit is inserted in each of the delay adjustment circuits, and each delay adjustment circuit is set to a delay amount corresponding to a difference in delay time between the delay time in each working line and the delay time in the protection line. Line switching method in the method. 4. The protection line is configured as a transmission system having the same delay time as that of one working line, and no delay adjustment circuit is provided between this one working line and another working line. The line switching system in the wireless communication system according to claim 3, wherein a delay adjusting circuit corresponding to a delay time difference from the one working line is provided. 5. A line monitoring device for monitoring the line quality of each of a plurality of working lines and one or more protection lines, the line monitoring device controlling the sending end switching device and the non-interruption switching device. 5. The line switching method in the wireless communication system according to claim 1, wherein an operation of switching the selected working line to the protection line is performed.