JPS63268318A - Standby set changeover system - Google Patents

Abstract

PURPOSE:To relieve the line with a simple constitution by connecting an alarm circuit to the reception side and a control at the transmission side, utilizing the information of the warning means in a receiver so as to detect an equipment fault of a transmission means, thereby applying changeover of standby set. CONSTITUTION:The warning circuit 5b at the reception side of an intermediate relay station has mainly two functions. As a first function, a reception fault of the active set is monitored and the warning to switch receivers 4a, 4b is sent to a control circuit 6b. As a 2nd function, both the reception fault of the active and standby sets are monitored and when a fault takes place simultaneously, the warning of simultaneous fault is sent through a transmission line 7 to the repeater station at the transmission side. On the other hand, the control circuit 6a, as well at the transmission side of the repeater station has two functions accordingly. Since reception abnormality, only at the simultaneous fault, is fed back to the repeater station of the transmission side as the warning, the disabled relief of the line due to the equipment fault of the transmitter is prevented without providing a transmission content discrimination circuit to the transmission side of the intermediate relay station.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a set protection switching system, and particularly to a set protection switching system suitable for use in a digital wireless transmission system having a relay station.

[Prior Art] In digital wireless transmission, a digital wireless transmission system is sometimes configured in which an intermediate relay station is installed between each wireless terminal station.

FIG. 3 is a block diagram of a digital wireless transmission system having such an intermediate relay station.

In the figure, 11 and 12 are wireless terminal stations, and 13 to 15 are intermediate relay stations, and digital signals are transmitted wirelessly between the wireless terminal station 11 and the wireless terminal station 12 via the intermediate relay stations 13 to 15. are doing.

In the above configuration, when transmitting a signal from the wireless terminal station 11 to the wireless terminal station 12, it is assumed that, for example, a device failure occurs in the transmitting device of the intermediate relay station 13.

At this time, unless the alarm circuit of the transmitting device is activated due to a failure at the intermediate relay station 13, the transmission line will not be rescued even though the line between the intermediate relay stations 13 and 14 becomes abnormal. A problem arises.

Therefore, in a digital wireless transmission system, even if such a situation occurs in a repeater, it is necessary to be able to switch from a faulty device to a normal device on the transmitting side.

FIG. 2 is a block diagram of an intermediate relay station that employs a conventional hot-and-by switching method in such a digital wireless transmission system. This set backup switching method is a method for saving the line by switching to a backup device prepared in advance for each device when a failure occurs.

In the figure, la and lb are transmission-default and reception-side hybrids, respectively, and distribute signals to transmitters 2a, 2b and receivers 3a, 3b of the set backup system. 4
a and 4b are switching devices, which are set reserve type transmitter 2;
The signals of a, 2b and receiving devices 3a, 3b are switched.

5a and 5b are alarm circuits on the transmitting side and receiving side, respectively, which notify the control circuits 6a and 6b when a device failure occurs in the transmitting devices 2a and 2b or the receiving devices 3a and 3b;
Set preliminary switching is performed by the switching devices 4a and 4b.

In the above configuration, on the transmitting side, a transmission signal is distributed by the hybrid LA, and modulated into a radio frequency signal by two transmitting apparatuses 2a and 2b, one for use and one for backup. Then, the - signal selected by the switch 4a is transmitted as a radio wave.

On the receiving side, the incoming radio waves are received by a hybrid lb using two receiving devices 3a, one in use and one in reserve.

Distribute to 3b. The distributed received signals are demodulated, and the one selected by the switch 4b is sent to the transmitting side for the next intermediate relay station.

In general, detection of a transmission abnormality is limited to a decrease in transmission output or a pulse interruption, and in these cases, the alarm circuit 5a switches the switch 4a.
An alarm as switching information was sent to the control circuit 6a of the controller.

On the other hand, reception abnormalities are detected by parity checks, frame synchronization loss, etc., and the W alarm circuit 5b sends an alarm to the control circuit 6b, and the switch 4b switches between the receiving devices 3a and 3b.

However, in order to check whether a signal with the correct content is being sent by detecting a transmission abnormality, the alarm circuit must have a function similar to that of the receiving device. This imposes a large cost burden, and it has generally not been carried out in practice.

In comparison, detection of a reception abnormality makes it possible to obtain information necessary to determine whether or not the received content is correct.

As described above, in the conventional set backup switching method, the switching information of the transmitting side switching device is insufficient compared to the switching information of the receiving side switching device.

[Problems to be solved] In the conventional set backup switching method described above, even if a device failure occurs on the transmitting side and the next intermediate relay station determines that the reception is better than that, the alarm circuit on the transmitting side will not work. There wasn't. For this reason, there was a problem in that the transmitter was not switched by the switch and the line was not repaired.

The present invention has been made in view of the above-mentioned problems.When the two receiving circuits of the hot standby system, the active and standby receiving circuits, detect a reception abnormality at almost the same time at an intermediate relay station,
The purpose of the present invention is to provide a set backup switching method for relieving a line by transmitting a simultaneous failure alarm by an alarm means through a transmission line, and by controlling means for controlling the switching means of a transmitting device to perform switching based on the simultaneous failure alarm. .

[Means for Solving Problems] In order to achieve the above object, the set backup switching method of the present invention connects a transmitting device and a receiving device via a wireless line and a transmission path, and the transmitting device has a plurality of transmitting means and , a switching means for selectively switching the transmitting means; a first alarm means for monitoring the plurality of transmitting means and issuing a fault alarm when detecting the occurrence of a fault; and controlling the switching means based on the fault alarm. The receiving device includes a receiving means, and a second device that monitors the receiving means and issues a failure alarm to the control means via a transmission path when a failure of the transmitting means is detected. This configuration includes an alarm means.

[Example code] Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 is a block diagram of an intermediate relay station that employs a set protection switching method according to an embodiment of the present invention. Note that parts common to or corresponding to those of the conventional example are denoted by the same reference numerals.

In the figure, 7 is a transmission line, and an alarm circuit 5 on the receiving side
b and the transmitting side control circuit 6a are connected.

In the above configuration, the function of the alarm circuit 5b on the receiving side and the control circuit 6a on the transmitting side is different from that of the conventional intermediate relay station shown in FIG.

Specifically, the alarm circuit 5b on the receiving side of the intermediate relay station in FIG. 1 mainly has two functions. The first function is to monitor current reception abnormalities and
This is to send an alarm for switching between a and 4b to the control circuit 6b. The second function is to monitor both the active and standby reception abnormalities and, when failures occur at the same time, to send out a warning of simultaneous failures to the transmitting relay station via the transmission path 7.

On the other hand, the control circuit 6a on the transmitting side of the relay station in FIG.
It has two functions corresponding to this.

The first function is to issue an alarm from the alarm circuit 5a in response to an abnormality in the transmitting device 2, as in the conventional control circuit.
This is a function to switch between a and 2b.

In addition, as a second function, transmission line 7 from the next intermediate relay station
The simultaneous fault alarm sent through the transmitting device 2
This is a function to switch between a and 2b.

In this way, in this embodiment, a reception abnormality detected on the receiving side is fed back as an alarm to the relay station on the transmitting side only when there are simultaneous failures. It is possible to prevent the line from being unable to be repaired due to a device failure in the transmitting device without adding a circuit to the transmitting side of Koya to determine whether the transmitted content is correct.

It should be noted that the present invention is not limited to the above embodiments, but includes various modifications within the scope of the gist. For example, since the amount of information to be transmitted is small, the transmission path is not limited to a specially provided transmission path, and a telephone line or the like can be used.

[Effects of the Invention] As explained above, the present invention utilizes the information of the alarm means in the receiving device to detect a device failure in the transmitting means and performs set backup switching. This has the effect of making relief possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an intermediate relay station that uses a set protection switching method according to an embodiment of the present invention, FIG. 2 is a block diagram of an intermediate relay station that uses a conventional set protection switching method, and FIG. 3 is a block diagram of an intermediate relay station that uses a conventional set protection switching method. 1 is an overall diagram of a digital wireless transmission system. la, lb: Hybrid 2a, 2b: Transmitting device (current and backup) 3a, 3b:
Receiving devices (active and spare) 4a, 4b: Switching devices 5a, 5b: Alarm circuits 6a, 6b: Control circuit 7: Simultaneous failure alarm transmission line

Claims (2)

[Claims] (1) A transmitting device and a receiving device are connected via a wireless line and a transmission path, and the transmitting device includes a plurality of transmitting means, a switching means for selectively switching between the transmitting means, and a monitoring device for monitoring the plurality of transmitting means. The receiving device includes a first alarm means that issues a fault alarm when the occurrence of a fault is detected, and a control circuit that controls the switching means based on the fault alarm. and a second alarm means that issues a failure alarm to the control means via a transmission line when a failure of the transmission means is detected, and a normal transmission means is selected when a failure occurs. Set reserve switching method. (2) The receiving means includes a plurality of receiving circuits, a switching circuit that selectively switches between the receiving circuits, and a control circuit that controls the switching circuit, and the second alarm means includes a plurality of receiving circuits, a switching circuit that selectively switches the receiving circuits, and a control circuit that controls the switching circuits. 2. The set backup switching system according to claim 1, wherein circuits are monitored, and if a reception abnormality occurs in a plurality of receiving circuits, it is assumed that there is a failure in the transmitting means and a failure alarm is issued.