JPH0453316A - Communication transmission system - Google Patents

Abstract

PURPOSE:To realize the transmission system with high reliability by selecting a standby line simultaneously, and making succeeding transmission even when any of incoming and outgoing lines in a block of an active line is faulty. CONSTITUTION:Terminal station equipments LTE1, LTE2 connecting respectively to digital terminal station equipments DTE provided to each terminal station are provided in the system and repeaters REP1, REP2 are interposed between the terminal station equipments LTE1, LTE2. When a fault such as a broken active transmission line takes place, signal lines for a main signal used for the transmission of supervisory control information are selected simultaneously to standby lines to continue the transmission of the main signal and the monitor control signal. Thus, the communication transmission system with high reliability is realized.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a communication transmission system, and in particular, to a communication transmission system that can operate without any hindrance even when an abnormality occurs in a relay transmission system such as a communication line disconnection. The present invention relates to a communication transmission system that is capable of transmitting data at low cost and ensuring reliability.

(Prior Art) In a digital transmission system using optical communication, optical cables are used to connect terminal stations, and a relay device is provided at an intermediate point to amplify the data while exchanging data between the terminal stations. Therefore, as a transmission line, separate lines are used for the outward route and for the return route, and these pairs are used as bare for communication with the other party's communication device. Incidentally, there is also one in which the transmission path is only unidirectional.

FIG. 5 shows an example of a monitoring device in a conventional relay transmission system, and in the figure, DTE is a digital terminal station,
LTE is a terminal station, RFP is a relay device, Sv is a monitoring device, a
is a main signal line, and b is a signal line for supervisory control. Main signal line a
There are two systems, one for the outward route and one for the return route, and the terminal stations LTE are connected to each other via these main signal lines a. Main signal line a
If the transmission distance is long, the signal will attenuate, so a repeater REP is provided for amplification along the way. The supervisory control signal line is a signal line provided separately from the main signal line a. Terminal LTE
and relay device REP are each provided with a monitoring device Sv, and the monitoring device Sv monitors the status of its own station (terminal station LTE and relay device REP). Each monitoring device SV is connected by a signal line for monitoring and control, and exchanges monitoring and control information.

The monitoring device SV is a circuit for quickly detecting failures, and monitors input signal interruption, error rate deterioration, transmission output level drop, etc., and outputs the information as monitoring control information.

Conventional systems with this type of configuration monitor input signal interruptions, error rate deterioration, transmission output level drops, etc. when transmitting the main signal via a line, and transmit this information to other stations as supervisory control information. Alternatively, a signal line other than the main signal line a is used to transmit the supervisory control signal between the monitoring device Sv of the installation station of the repeater RFP and the monitoring device S of the installation station of the terminal LTE. Ta. However, with this method, when the relay span is long as in the optical transmission method, a repeater must be installed for the supervisory control signal line, and if the signal line is disconnected, the supervisory control This means that the signal cannot be sent, resulting in loss of control, which also poses a problem in terms of main signal transmission.

(Problems to be Solved by the Invention) Conventional digital transmission systems using optical communication either connect terminal stations that perform transmission and reception with a main signal line via a relay device to exchange data, or Monitoring equipment is installed at each station for monitoring purposes. For signal transmission of each monitoring device, a signal line provided separately from the main signal line a was used. However, this system has the disadvantage that if the relay span is long, as in the optical transmission system, a repeater must be installed for the supervisory control signal line, which increases costs.

In order to solve this drawback, it is possible to use a method in which the main signal line is used to transmit the supervisory control signal, and the supervisory control signal is transmitted as sub information together with the main data. Even if there is, if the main signal line is disconnected, transmission will no longer be possible. However, in general, it is common to install a backup line as a substitute when the main signal line system becomes abnormal, so when the main signal line is disconnected, the transmission is switched to the backup line and transmitted. It will be a good thing if you do this.

However, when the main signal line is disconnected, the problem becomes how to switch the supervisory control signal to the backup line. In other words, if the main signal line is prepared as a backup line, a control command is sent to each monitoring device to switch from the disconnected line of the working system to the backup line, and communication is maintained by switching to the backup line. It is possible to continue, but if the main signal line, which is the line of the working system, is disconnected,
Since the monitoring and control signals are also cut off, it becomes impossible to receive information from each monitoring device, as well as to send and receive control commands to each monitoring device.
A major issue is whether each station should switch over to the backup line to send and receive signals for monitoring and control. If this cannot be done properly, the system will become confused and the system will go down.

Therefore, the purpose of this invention is to prevent abnormalities such as disconnection of the current transmission line when using a transmission line (transmission line) that transmits the main signal for the transmission of supervisory control signals. When a problem occurs, the main signal lines used for transmitting supervisory control information can be switched all at once to the backup line, allowing the main signal and supervisory control signal transmission to continue, maintaining reliability. The purpose of this invention is to provide a communication transmission system that enables communication.

[Configuration of the Invention (Means for Solving the Problem) In order to achieve the above object, the present invention is configured as follows. That is, first, a plurality of terminal stations and relay stations are connected by a plurality of transmission lines for main signal transmission, and each system is composed of uplink and downlink dedicated lines, and the main signal transmission lines are In a communication transmission system in which a transmission frame is used for transmission, and supervisory control information between a terminal station and a relay station is added to the transmission frame and transmitted, the relay station includes means for generating a transmission frame signal. and a switching means for selectively switching and transmitting the transmission frame signal generated by the transmission frame signal generation means and the transmission frame received from the transmission path, and a switching means for adding supervisory control information to the transmission frame provided via the switching means. a transmission means for sending out the transmission frame signal to the transmission path, and a transmission frame signal generated by the transmission frame signal generation means when the input from the transmission path used for the transmission of the supervisory control information is monitored, and when the transmission path becomes abnormal; The configuration is such that the switching means is controlled to switch to the transmitting means, and a transmission path switching command is output as monitoring control information to be given to the transmitting means.

Second, in addition to providing multiple main signal transmission lines, each system consists of uplink and downlink dedicated lines, and at least one of the multiple lines is used as a backup line, so that when the working line fails, and a transmission system that connects a terminal station and a relay station to the transmission path, and sends a transmission signal including the main signal and supervisory control information to the transmission frame to the terminal station and the relay station. , a transmitting/receiving means having a receiving system for separating the main signal and supervisory control information from the received frame is provided for each system of the transmission path, and the transmission state is monitored by monitoring the received frame. In the transmission system, the relay station includes a frame generating means for generating a predetermined transmission frame, and the monitoring means detects an abnormality on the upper side of the working line. means for supplying the transmission frame generated by the frame generation means to the transmission system of the working line when detected; ,
In addition to providing a function to implement control in response to the control command, when an abnormality is detected on the upper side of the working line,
A function is provided to generate a control command for switching to the backup line among the transmission lines as the monitoring control information, and then to switch and control the transmitting/receiving means to switch the own station to the backup line. Configure.

(Function) In this system with such a configuration, the transmitting terminal station inserts the main signal and supervisory control information into a transmission frame and transmits it downstream over the working line, and each downstream station inserts the main signal and supervisory control information into the transmission frame. information from the transmission frame, performs supervisory control based on the supervisory control information, and inserts supervisory control information to be given to downstream stations, including supervisory control information at the own station, into the transmission frame and transmits it to the downstream side. If a transmission abnormality occurs on the upstream side, the monitoring device at the downstream station detects the transmission abnormality on the upstream side, generates monitoring control information to instruct switching to the protection line, and then automatically The station is switched from the working line to the protection line, and the protection line is started to be used as the working line for transmitting supervisory control information.

A station that detects a transmission abnormality on the upstream side sends a transmission frame generated by its own frame generation means to its own transmission system, and adds its own monitoring control information to this transmission frame. , to be transmitted downstream. Therefore,
On the downstream side, it is possible to issue a command to switch to the protection line by using the available section of the working line where the abnormality has occurred, and since the line has an upstream and downstream side, it is possible to instruct a switch to the protection line by using the available section of the working line where the abnormality has occurred. can also command all stations to switch to protection lines. In response to this command, the line is immediately switched to the protection line, so that the main signal and supervisory control information can be transmitted normally again thereafter.

In the present invention, a plurality of terminal stations and a relay station are connected by a working line and a protection line, and in order to transmit a supervisory control signal between the monitoring means of the relay station and the monitoring means of the terminal station, for example, The relay station uses prepared sub-information bits, etc., and the relay station has a function of generating a transmission line frame signal, and when an abnormality is detected on the input side, it sends a message to the output side.
In a transmission system that outputs generated transmission line frame signals, when the working line transmitting the supervisory control signal is disconnected, when switching from the disconnected working line to a protection line or another working line, disconnection of the working line The system is characterized in that the transmission path of the supervisory control signal is switched in response to a switching command sent to the uplink and downlink from the relay station that detects this.

In such a configuration, sub information bits provided in advance in the main signal are used for supervisory control signal transmission between stations, but the relay station has a function of generating transmission frames, and the supervisory control signal is transmitted between stations. This generated transmission frame is used when there is an input error from the working line, which is the transmission path used for transmission, and when an abnormality occurs such as disconnection of the working line, the supervisory control signal line is transferred from the working line where the abnormality occurred to the backup line. When switching to the backup line, the relay station that detects the abnormality sends a switching signal generated from its own monitoring device to both the uplink and downlink of the working line, and switches to the protection line.
Enables transmission of supervisory control signals.

In this way, this device has the function of generating transmission frames from the relay station, so even if the relay station detects a line disconnection at the upper level (upstream), the lower level (downstream) will not receive the generated transmission frame. By outputting it, a supervisory control signal can be transmitted to the lower level.

Furthermore, by transmitting a switching signal to the line in the opposite direction from the relay device that has detected line disconnection, it is possible to switch the monitoring device with less loss of supervisory control signals due to line disconnection.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

Fig. 1 is a system configuration diagram showing one embodiment of the present invention;
FIG. 3 is a diagram showing the configuration of a relay device (relay station) showing an embodiment of the present invention, and FIG. 3 is a block diagram showing the configuration of a terminal device. As shown in Fig. 1, this system includes a terminal device LTE1 and a terminal device LTE2 that are respectively connected to a digital terminal device DTE installed in each terminal station. A configuration is shown in which a relay device REP1 and a relay device REP2 are interposed between the LTE2 and LTE2, and two transmission lines (transmission lines) are installed, a first system and a second system. Each system consists of an uplink and a downlink, the transmission line of the first system consists of an uplink Lla and a downlink L2a, and the transmission line of the second system consists of an uplink Llb and a downlink L2b.

Each terminal device has a monitoring device 5V2a and a transmitting/receiving device T.
/Ra, and each relay device has a monitoring device SV2 and a transmitting/receiving device T/R. Since there are two transmission lines, in this case, each station has two systems of transmitter/receiver T/Ra and transmitter/receiver T/R, and are controlled by respective monitoring devices 5V2a and SV2.

FIG. 2 is a configuration example of a relay device (relay station) showing an embodiment of the present invention, in which SV2 is a monitoring device and T/R is a transmitting/receiving device. There are a plurality of transmitting/receiving devices T/R (as many as the number of transmission lines installed), and only one system designated by the monitoring device SV2 is active.

The transmitting/receiving device T/R consists of the following elements. That is, D.E.
P is extraction circuit, INS is insertion circuit, SW is switching circuit, F
G is a transmission frame generation circuit, and AMP is a reproduction circuit.

Among these, the sampling and closing circuit DEP is a circuit that separates and extracts the supervisory control signal from the signal of the received transmission frame transmitted and input from the upper level (upstream side of the main signal line),
The reproducing circuit AMP is a circuit that reproduces the main signal, and performs level equalization, amplification, etc., and outputs the signal. The switching circuit SW selects the signal from the reproduction circuit AMP and inputs it to the insertion circuit INS during normal times (when the line is normal), and when it is abnormal (when the line is normal).
When the line is disconnected), the input from the transmission frame generation circuit FG is selected and input to the insertion circuit INS, and this switching is unnecessary! This is performed using the line disconnection detection output of the circuit DEP.

The transmission frame generation circuit FG is a circuit that generates a transmission frame in a predetermined format, and one sampling circuit D
EP is a circuit for superimposing the supervisory control signal output from the monitoring device SV2 on the transmission frame output through the switching circuit sw, and the transmission frame has a main signal area and a supervisory control signal area (sub information bit area, etc.) Therefore, the supervisory control signal is inserted into the bit position of the supervisory control signal area.

The monitoring device SV2 is a circuit for detecting failures as soon as possible, and upon receiving the output signal of the sampling circuit DEP, it monitors input signal interruption, error rate deterioration, transmission output level drop, etc., and uses the information to monitor and control. In addition to outputting this information as information, when an input signal disconnection is detected, a command is issued to the downstream side to switch the transmission of the transmission frame to the protection line. It has the function of switching and controlling.

Each terminal device has one monitoring device 5V2a and transmitting/receiving devices T/Ra for the number of transmission line systems.
However, in order to distinguish each system, the first system is given a subscript 1, and the second system is given a subscript 2.

FIG. 3 is a block configuration diagram of the terminal equipment portion showing an embodiment of the present invention, in which 5V2a is a monitoring device, DEPa is an extraction circuit, IN5a is an insertion circuit, S W a is a switching circuit,
AMPa is an amplifier circuit.

Among these, the sampling circuit DEPa is a circuit that separates and extracts the supervisory control signal from the signal of the received transmission frame transmitted from the upper level (upstream side of the main signal line), and the amplifier circuit AMPa is the main circuit. This is a circuit that amplifies the signal, and also has a level equalization function in the receiving system. Said switching circuit S
W a is a circuit that opens and closes the connection with the line, and is controlled by the monitoring device 5V2a. The insertion circuit 1N5a is a circuit that inserts and outputs the monitoring control information from the monitoring device 5V2a into the transmission frame, and this output is sent to the transmission path. The insertion circuit IN5a superimposes the supervisory control signal output from the monitoring device 5V2a on the input transmission frame, but since the transmission frame is divided into a main signal area and a supervisory control signal area, the supervisory control signal is superimposed on the input transmission frame. The supervisory control signal is inserted into the bit position of the area.

The monitoring device 5V2a receives the output signal from the sampling circuit DEPa, detects failures, monitors input signal interruption, error rate deterioration, transmission output level drop, etc., and outputs the information as monitoring control information. When it detects a disconnection of the transmitting signal or receiving signal, it issues a command to the downstream side to switch to the protection line for transmission of transmission frames, and then immediately switches its own system to the protection line system and controls the transmission. Then, it has the function mentioned above.

Each repeater or terminal equipment has multiple systems of transmitting and receiving equipment, each with a receiving system and a transmitting system, and the main signal line (transmission line)
A number of lines are provided for each transmitter/receiver, so that one system is used as a working line and the other lines are used as protection lines.

The monitoring device SV2 controls each transmitting/receiving device so that one system is used as a working system and the other systems are used as a backup system. Furthermore, this system does not have a signal line for monitoring and control.

The operation of this device having such a configuration will be described below.

This system has two transmission lines, one of which is currently in use.
The other system is used as a backup system, and here, as an example, a case will be described in which the first system is used as an active system and the second system is used as a backup system. Information transmitted over a line (transmission path) has a frame structure, and this frame main signal and a supervisory control signal are multiplexed.

In the terminal equipment, only the switching circuit S W a of the first system is closed, and when transmission information (main signal) is sent from the connected communication terminal of the terminal equipment, this main signal is inserted into a predetermined area of the transmission frame. The supervisory control information is sent to the insertion circuit IN5a, and is inserted into the transmission frame by the insertion circuit IN5g using a predetermined area of the transmission frame, that is, the sub information bit provided in advance in the main signal, and then transmitted in the first system. sent out on the road.

When the relay device receives a signal (received transmission frame) input from the upper layer (upstream side of the first transmission path),
This signal is first input to the sampling circuit DEP, which separates the monitoring control signal and sends the remainder to the reproducing circuit AMP. Then, convert this sampling into circuit DE
The supervisory control signal separated at P is input to the supervisory device SV2. The remainder from which the supervisory control signal is extracted is the main signal component, which is equalized and amplified by the reproduction circuit AMP and input to the switching circuit SW. Switching circuit S
During normal operation, W selects the signal from the reproduction circuit AMP, and the selected signal is input to the insertion circuit INS. The insertion circuit INS inserts the monitoring control signal from the monitoring device SV2 and sends it to the downstream side.

On the other hand, the monitoring device SV2 receives the monitoring control signal separated by the sampling circuit DEP, and if there is control information, it follows it.
In addition, the insertion circuit INS is given supervisory control information at its own station and supervisory control signals to be transferred out of the supervisory control signals extracted from the transmission frame. Therefore, in a normal state, the main signal can be amplified, and the monitoring and control information at the own station and the received monitoring and control signal to be transferred can be inserted and relayed to the downstream side.

When the terminal device on the receiving side receives a signal (received transmission frame) input from the upper layer (upstream side of the transmission path of the first system) in the receiving system of the first system, this signal is sent to the extraction path DEP. The sampling circuit DEP separates the monitoring control signal, and the remaining signal is sent to the amplifier circuit AMP.
Send to a.

The monitoring control signal separated by this sampling circuit DEP is input to the monitoring device 5V2a. The remainder from which the supervisory control signal is extracted is a main signal component, which is equalized and amplified by the amplifier circuit A M P a and input to the switching circuit S W a.

Since the switching circuit S W a of the first system is closed,
A communication terminal connected to the terminal device receives this signal as a reception signal.

On the other hand, the monitoring device SV2 receives the monitoring control signal separated by the sampling circuit DEP, and if there is any control information, it follows the monitoring control information at its own station or the monitoring control signal extracted from the transmission frame. The supervisory control signal to be transferred is given to the insertion circuit INS. Therefore, in a normal state, the main signal can be amplified, and the monitoring control information at the own station and the received monitoring control signal to be transferred can be inserted and relayed to the downstream side.

Such operations are performed in both directions, uplink and downlink. The above is the operation in the normal state, and the state diagram is as shown in FIG. 4(a).

Next, the operation at the time of transmission line failure will be explained.

Now, the uplink/downlink Lla in the transmission line of the working system,
Suppose that a line disconnection occurs at point A of one line Lla of L2a (Figure 4 (b)). Then, since the transmission frame sent on the line cannot be obtained, the Sampling circuit DRP of the uplink reception system in the transmitting/receiving device T/R1 of the relay device REPI located at
1, the supervisory control signal cannot be extracted.

That is, the sampling circuit DRP1 detects that no transmission frame is input, and as a result, the monitoring device SV2 in the transmitting/receiving device T/R1 of the relay device REPI detects a line disconnection. When line disconnection is detected, the relay device REP
The monitoring device SV2 in the transmitting/receiving device T/R1 of I controls switching of the switching circuit SW. As a result, the relay device REP
The switching circuit SW in the transmitting/receiving device T/R1 of I performs a switching operation to select the output of the transmission frame generation circuit FG instead of the output of the reproduction circuit AMP. In addition, the monitoring device SV2 that has received the line disconnection detection output outputs a monitoring device switching signal to the insertion circuit INS on both the uplink Lla and downlink L2a of the first transmission line.

In the insertion circuit INS, the switching circuit SW switches to send out the output of the transmission frame generation circuit FG, so it receives the transmission frame generated by the transmission frame generation circuit FG,
The monitoring device switching signal is inserted into a predetermined bit position for the monitoring control signal in this transmission frame and transferred to the downstream side. After that, the monitoring device SV2 of the relay device REPI,
Switch the transmission line for supervisory control signals of the own station from the working line (transmission line of the first system) to the protection line (transmission line of the second system).

As a result, the downstream side extracts the monitoring device switching signal inserted into the predetermined bit position for the monitoring control signal and learns that there is a command to switch the monitoring device, and the station that receives the monitoring device switching signal automatically In response to this, the monitoring device SV2 of the station switches the working line of its own station from the first system transmission line to the second system transmission line, which is a protection line. This results in
The supervisory control signal transmission line has been switched from the working line to the protection line at this point, and the monitoring device switching signal must have been output to the working uplink and downlink lines at the time of the failure of the working transmission line. , the other stations will immediately switch from the working line (transmission line of the first system) to the protection line (transmission line of the second system), so they can resume normal operation using the transmission line of the second system. Transmission can now be resumed (FIG. 4(C)).

To explain Fig. 4, this Fig. 4 shows an example of the switching method of the monitoring device according to the present invention, and if the system is operated in the state (a), the relay devices REPI and REP2 in the working line are switched. If the line is disconnected at point A on the downlink Lla between the two, the result will be as shown in FIG. The relay device RFP2, which has detected a line fault, sends a signal composed of a self-generated transmission frame to the subsequent downlink, that is, to the downstream side of its own station position on the downlink Lla.

Then, in the relay device RFP2, the monitoring device SV2 of its own station sends a monitoring device switching signal to both the downlink Lla and the uplink L2a. Also, it switches the supervisory control signal transmission line from the working line to the protection line (downlink Llb and uplink L2b). Next, the upper layer of relay device RFP2,
The devices located at each lower level switch the supervisory control signal transmission line from the working line to the protection line (downlink Llb and uplink L2b) in response to the monitoring device switching signal from the relay device RFP2. As a result, the system becomes as shown in Figure (e), and transmission can be resumed using the protection line.

As explained above, this system has multiple main signal transmission lines, and each system consists of uplink and downlink dedicated lines, with at least one of the multiple lines serving as a backup line, and a working line. In addition, a terminal station and a relay station are connected to the transmission line, and a transmission signal including the main signal and supervisory control information added to the transmission frame is sent to the terminal station and relay station. Transmitting/receiving means having a transmitting system and a receiving system that separates the main signal and supervisory control information from the received frame are provided for each system of the transmission path, and also monitors the received frame and determines the transmission status. In a transmission system configured to include monitoring means for monitoring and generating monitoring control information, the relay station includes frame generation means for generating a predetermined transmission frame;
means for providing the transmission frame generated by the frame generating means to the transmission system of the working line when the monitoring means detects an abnormality on the upper side of the working line; If there is a control command in the monitoring control information obtained by the system, a function is provided to implement control in response to the control command, and when an abnormality is detected on the upper side of the working line, one of the transmission lines , which is configured to have a function of generating a control command for switching to the backup line as the monitoring control information, and then controlling switching of the transmitting/receiving means to switch the own station to the backup line. It is. Then, the transmitting terminal station inserts the main signal and supervisory control information into a transmission frame and transmits it downstream over the working line, and each downstream station separates the main signal and supervisory control information from the transmission frame and performs supervisory control. In addition to performing supervisory control based on the information, supervisory control information that should be given to downstream stations, including supervisory control information at the own station, is inserted into the transmission frame and transmitted to the downstream side, thereby preventing transmission abnormalities on the upstream side. When this occurs, the downstream station's monitoring device detects the transmission abnormality on the upstream side, generates monitoring control information to instruct switching to the protection line, and then switches its own station from the working line to the protection line. This protection line starts to be used as a working line.

A station that detects a transmission abnormality on the upstream side sends a transmission frame generated by its own frame generation means to its own transmission system, and adds its own monitoring control information to this transmission frame. , to be transmitted downstream. Therefore,
On the downstream side, switching to the protection line can be commanded by using the available section of the working line where the abnormality has occurred, and since the line has upstream and downstream sides, even if one section exhibits an abnormality, all stations can be instructed to switch to the protection line. In response to this command, the line is immediately switched to the protection line, so that the main signal and supervisory control information can be transmitted normally again thereafter.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with appropriate modifications within the scope of the gist thereof.For example, in the above embodiments, the transmission path is Although the number of systems is two, it is also possible to have more systems. In this case, the working and backup systems can be prioritized and switched according to this priority, or the system to be switched and used can be specified in the supervisory control signal. All you have to do is make it possible. Alternatively, there may be a plurality of working lines, and one of them may be used for transmitting supervisory control information. In this case, when the working line used for supervisory control signal transmission becomes abnormal, in order to change the working line to a backup line, the supervisory control signal is sent using the abnormal working line, and the subsequent monitoring This protection line may be used for transmitting control signals.

[Effects of the Invention] As detailed above, according to the present invention, the transmission line for transmitting the main signal is configured as an uplink and a downlink, and a plurality of these transmission lines are provided. At least one of the lines is used as a backup line, and the main signal and the supervisory control signal are transmitted in frames, and an emergency transmission frame generation means is provided. An emergency transmission frame is used to send supervisory control information for switching the protection line to the downstream side of the line, and the transmission line is immediately switched to the protection line, so either the upstream or downlink in a section of the working line is Even if an abnormality occurs, it becomes possible to switch to the backup line all at once and perform subsequent transmissions, allowing the relay transmission system to operate without any problems and providing a highly reliable transmission system.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing an example of the configuration of a relay device (relay station) showing an embodiment of the present invention, and FIG. FIG. 4 is a block diagram showing a configuration example of a terminal device in the inventive device, FIG. 4 is a diagram for explaining an example of system switching operation in the inventive system, and FIG. 5 is a diagram for explaining a conventional example. REPI, REP2...repeater, Llb...uplink, L2b...downlink, SV2, 5V2a...monitoring device, T/R, T/Ra...transmission/reception device, DEP/
...Extraction circuit, INS...Insertion circuit, SW...Switching circuit, FG...Transmission frame generation circuit, AMP...
regeneration circuit. Applicant's agent Patent attorney Takehiko Suzue

Claims (3)

[Claims] (1) Multiple terminal stations and relay stations are connected by multiple transmission lines for main signal transmission, and each system consists of uplink and downlink dedicated lines, and In a communication transmission system using a transmission frame, and in which supervisory control information between a terminal station and a relay station is transmitted by being added to the transmission frame, the relay station includes means for generating a transmission frame signal, and a means for generating a transmission frame signal; A switching means for selectively switching and transmitting a transmission frame signal generated by the transmission frame signal generation means and a transmission frame received from a transmission path, and a switching means for adding supervisory control information to the transmission frame given through the switching means and transmitting the transmission frame to the transmission path. a transmitting means for transmitting the supervisory control information, and an input from a transmission line used for transmitting the supervisory control information, and when the transmission line becomes abnormal, switching to the transmission frame signal generated by the transmission frame signal generating means. A communication transmission system comprising: monitoring means for controlling the switching means and outputting a transmission line switching command as monitoring control information to the transmitting means. (2) In addition to providing multiple main signal transmission lines, each system consists of uplink and downlink dedicated lines, and at least one of the multiple lines is used as a backup line to serve as an alternative line in the event of a failure of the working line. In addition, a terminal station and a relay station are connected to the transmission path, and a transmission system that sends a transmission signal including the main signal and supervisory control information to the transmission frame to the terminal station and the relay station, and a reception frame. Transmitting/receiving means having a receiving system for separating the main signal and supervisory control information from each other are provided for each system of the transmission path, and also monitors the received frame to monitor the transmission state. In a transmission system configured to include a monitoring means for generating control information, the relay station includes a frame generation means for generating a predetermined transmission frame, and when the monitoring means detects an abnormality on the upper side of the working line. , means for providing the transmission frame generated by the frame generating means to the transmitting system of the working line, and the monitoring means is configured to control the control command if there is a control command in the monitoring control information obtained by the receiving system of the transmitting/receiving means. A function is provided to perform control in response to a command, and when an abnormality is detected on the upper side of the working line, a control command for switching to the backup line among the transmission lines is provided in the supervisory control information. 1. A communication transmission system characterized by having a function of switching and controlling said transmitting/receiving means so as to generate a signal and then switch the own station to said backup line. (3) Multiple terminal stations and relay stations are connected by multiple transmission lines for main signal transmission, and each system consists of dedicated uplink and downlink lines, and is a communication transmission system in which a transmission frame is used, and sub information bits prepared in advance in a main signal are used for transmission of supervisory control information between a terminal station and a relay station. includes a frame generation means for generating a predetermined transmission frame, a transmission system and a reception system, which are provided correspondingly to each system of the transmission path, and send out a transmission signal including the transmission frame plus the main signal and supervisory control information. A transmitting/receiving means having a receiving system that separates the main signal and supervisory control information from the frame is provided for each system of the transmission path, and the supervisory control information obtained by the receiving system of the transmitting/receiving means is If there is a command, there is a function to implement control in response to the control command, and when an abnormality is detected on the upper side of the line used for transmitting the supervisory control information, another predetermined function of the transmission line is activated. monitoring means having a function of generating a control command for switching to a line as the monitoring control information, and then controlling switching of the transmitting/receiving means to switch the own station to the predetermined line; If there is a control command in the monitoring control information,
A function to implement control in response to the control command, and a function to switch to another predetermined line among the transmission lines when an abnormality is detected on the upper side of the line used for transmitting the supervisory control information. generating a control command as the monitoring control information;
1. A communication transmission system comprising: a monitoring means having a function of switching and controlling said transmitting/receiving means so as to thereafter switch its own station to said predetermined line.