JPH077932B2 - Multidirectional communication system - Google Patents

Description

The present invention relates to a multi-directional multiplex communication system, and in particular to demand
The present invention relates to detection and switching control of a device failure of a working / standby system in a master station of a multi-directional multiplex communication system using an assign system.

[Conventional technology]

The multi-directional multiplex communication system is designed for efficient communication between one master station and a plurality of slave stations that are scattered in terms of position. Information is time-division multiplexed (TDM) and transmitted. At each slave station, the information that is the subject of its own station is separately selected and taken out. On the other hand, time division multiple access (TDMA: Time Division Multiple Access) in which predetermined information is transmitted from each slave station to the master station as a burst-like signal only during a predetermined time period allocated to the own station.
e Access) is performed, and the information from each slave station is separated and output at the master station.

In this method, since the device of the master station is common to the lines between each slave station, the failure of the device of the master station causes all line failures, so the device of the master station is currently in use. A redundant configuration with a spare is taken. In the case of the pre-assignment method in which a transmission time zone is assigned to each slave station in advance in the TDMA method, a transmission line corresponding to the time zone is always formed between the master station and each slave station. There is. Therefore, in order to monitor equipment failure in the master station, switching control to the standby system can be performed by constantly monitoring these transmission paths and detecting transmission path failures with all slave stations.

A conventional crisis monitoring and switching control system of the master station will be described with reference to FIGS. 3 and 4. Transmission information 1a to 1n to each slave station is converted into a TDM signal 2 by a channel processing circuit 106a to 106n from an input continuous signal to a TDM signal 2 in a predetermined time zone (hereinafter referred to as a channel) on a TDM frame designated in advance, The branch circuit 105 allows the working transmitter 100 and the spare transmitter 100 '.
Are input respectively. In each transmitting unit, the baseband processing circuits 101 and 101 'multiplex the frame synchronization signal, the line monitoring signal, etc., and the baseband shown in FIG.
TDM frame signals 4, 4'are created. These baseband TDM frame signals 4 and 4'are modulated by modulators 102 and 102 ', and converted into predetermined frequencies by transmission circuits 103 and 103'. The outputs 6 and 6'of the transmission circuits 103 and 103 'are the transmission switching circuit 10
It is selected to the normal side by 4 and is transmitted to each slave station as transmission output 7.

On the other hand, the received signal 15 from each slave station is a burst signal of each slave station as shown in FIG. 4 (B), and is input to the working receiver 200 and the spare receiver 200 'by the branch circuit 204. In each receiving section, the branched signals 14, 14 'are frequency-converted by the receiving circuits 203, 203', respectively, and further demodulated by the demodulating circuits 202, 2 '.
It is demodulated by 02 '. These demodulated signals 12 and 12 'are separated into line supervisory signals and the like by the reception baseband processing circuits 201 and 201', and the normal side is selected by the reception switching circuit 205. Each of the channel processing circuits 206a to 206n separates the corresponding channel signal and performs speed conversion, and outputs reception signals 10a to 10n, respectively.

In this system, especially regarding the fault monitoring of the receiving units 200 and 200 ', the received signal is a burst signal as shown in FIG. 4, and the reception electrolysis is performed for each burst because each slave station is scattered in position. Is different. Therefore, the demodulators 202, 20
A limiter amplifier is usually used to keep the 2'input level constant. Therefore, even if an attempt is made to monitor the reception system failure by the input level of the demodulator, it cannot be distinguished whether the input is a normal burst signal or simple thermal noise, and sufficient accuracy cannot be obtained. For this reason, normally, a parity check or the like is performed on the information signal on the transmitting side for each burst to add a monitoring bit. On the reception side, the reception baseband processing circuit monitors them, and if a parity error of all channels exceeds a certain threshold value, it is judged as a reception failure, and a reception alarm 18 or 18 'is sent to the alarm control circuit 300, and the normal side is transmitted. The switching control was performed by sending the switching signal 17 to the transmission and reception switching circuits, respectively.

[Problems to be Solved by the Invention]

The above-mentioned failure monitoring method of the receiving system, in the pre-assign method in which the transmission time zone is assigned to each slave station in advance,
The fact that the signal of each station is always received correctly can be the basis for determining that the receiving system device is normal. However, in the demand assign method, in order to improve the utilization efficiency of the non-rotating circuit, the transmission is stopped while the information is not required to be transmitted, and the transmission request is made to the master station only when the information is required.
Have a user specify a channel to use and occupy that channel for as long as necessary. For this reason, the radio channel used is not always constant and changes momentarily, and depending on the time of day, there may be a state in which the reception signal of the master station does not exist because all slave stations do not require transmission. On the other hand, the above-mentioned reception monitoring method has a drawback in that it cannot perform monitoring at all when the transmission of all the slave stations is stopped because the occupation information of the wireless channel is required every moment.

[Means for Solving the Problems]

According to the present invention, in a multi-directional multiplex communication system adopting a demand assign system, a master station sequentially polls a slave station for a test control command through an information transmission channel, and the polled slave station tests according to the test control command. A signal is transmitted through the information transmission channel, and the master station is provided with means for separating and monitoring these test signals in the working / standby system, respectively. It is characterized by performing a spare switching control.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS.
In the demand assign system, a channel CH-p and information channels CHa to CHn are prepared as shown in FIG. 2 for controlling outgoing / incoming call connection of each slave station. Transmission signal to slave station 1a ~
1n is converted into a TDM signal 2 by being converted into a predetermined channel on the wireless DTM frame designated by the channel processing circuits 106a to 106n, and the branch circuit 105 causes the active transmission section 100,
It is input to the preliminary transmission unit 100 '. At this time, the control circuit 400 causes the polling call connection signals 8 and 8'to be generated on the channel CH-p.
In addition, the test control commands 9 and 9'are input to arbitrary information channels. After TDM multiplexing, modulation and frequency conversion are performed as in the conventional case, and the transmission output 7 is obtained. On the other hand, the receiving system is also subjected to frequency conversion / demodulation as in the conventional case, and the receiving baseband processing circuits 201, 201 'control channel signals 16,1.
The test signals 18 and 18 'sent from the slave station are separated according to 6'and the test control commands 9 and 9'and are output to the control circuit 400, and at the same time, via the reception switching circuit 205, each channel processing circuit 206a ... Output to 206n.

In this configuration, the control circuit 400 sequentially polls the slave stations belonging to the local station by using the polling call connection signals 8, 8'and sends the test control command 9, 9 '. According to 9,9 ', the test signal 18,18' is transmitted to the master station via an arbitrary information channel. Therefore, the control circuit 400 of the master station monitors the test signals 18 and 18 'from the designated slave station, and when the test signals 18 and 18' are received without error in both the receiving working and standby systems, Both stations can be judged to be normal. The test signal 1
When 8,18 'is received as correct, it can be determined that the slave station is normal and the error side of the local station reception system test signal 18,18' is a failure.
Further, when the test signals 18 and 18 'are in error for both the working and protection stations, there is a possibility of failure of the slave station or simultaneous failure of the working and protection stations of the own station. 1
It is possible to judge whether the slave station or the local station is faulty by checking the 8'correctness.

These are summarized in Table 1.

Usually, since the probability of simultaneous failure is sufficiently small, it can be determined that the failure is the failure of the slave station (4 in Table 1) or the transmission failure of the local station (5 in Table 1). Therefore, the control circuit 400 sends the switching control signal 17 based on this determination to the transmission switching circuit 104,
By sending the signal to the reception switching circuit 205 and performing switching, it is possible to detect a fault relatively easily and surely even in the demand assign method.

〔The invention's effect〕

As described above, according to the present invention, in order to monitor each slave station that is not transmitting in the demand assign method whether or not there is a failure, a test control signal is sequentially polled using the information channel. However, since the slave station transmits the test signal to the master station using the information channel according to the test control signal, the information channel can be effectively used in time. In addition, it is possible to monitor all slave stations by checking the correctness of the test signal, and at the same time, it is possible to reliably and easily monitor the fault of the own station, which has the effect of increasing the reliability of the entire system.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of the present invention, FIG. 2 is a diagram showing an example of a frame configuration of the present invention, FIG. 3 is a configuration diagram in a conventional pre-assign system, and FIG. An example of the frame configuration of is shown. 100,101 '... Transmitter (active / spare), 101,101' ... Transmission baseband processing circuit, 102,102 '... Modulator, 103,10
3 '... Transmission circuit, 104 ... Transmission switching circuit, 105 ... Branch circuit, 106 ... Transmission channel processing circuit, 201, 201' ... Reception baseband processing circuit, 202, 202 '... Demodulator, 203, 203'
...... Reception circuit, 204 …… Branching circuit, 205 …… Reception switching circuit, 2
06 ... Receiving channel processing circuit, 300 ... Alarm control circuit, 400 ... Control circuit.

Claims (1)

[Claims] 1. A predetermined master station and a plurality of slave stations subordinate to the master station are provided, and a predetermined transmission channel is assigned to the slave station only when the slave station needs to transmit information. In the multi-directional multiplex communication system which adopts the demand assign system, the master station sequentially polls the slave station for a test control command through the information transmission channel, and the polled slave station sends a test signal according to the test control command. The master station is provided with means for sending out through the information transmission channel, and the master station is provided with means for monitoring these test signals by separating them in the working / standby system respectively, and depending on whether the test signal is correct or incorrect, the master station Multidirectional communication system characterized by performing active / standby switching control in.