JPH01256830A - Multi-direction multiplex communication system - Google Patents

Abstract

PURPOSE:To contrive timewise effective utilization of an information channel by allowing a master station to monitor a test signal from a slave station while separating it by an active and a standby system in a multi-direction multiplex communication system adopting the demand assign system and applying the changeover control of active/standby system in response to the correctness of the test signal. CONSTITUTION:A control circuit 400 uses polling call connection signals 8, 8 to apply sequential polling to slave stations belonging to its own station and sends test controls instructions 9, 9'. Then a slave station sends test signals 18, 18' to the master station through an optional information channel according to the test control instructions 9, 9'. Thus, the control circuit 400 of the master station monitors the test signals 18, 18' from the designated slave station and when the test signals 18, 18' are received to the active and standby system without error, both the slave station and its own station are decided to be normal. When any of the test signals 18, 18' of the active/standby system is received correctly, the incorrect test signals 18, 18' of the slave station is decided to be faulty. Thus, the fault is detected surely and comparatively easily even in the demand assign system.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a multidirectional multiplex communication system, and in particular to a demand-based multiplex communication system.
This paper relates to equipment failure detection and switching control for active and standby systems in a master station of a multidirectional multiplex communication system using an assignment method.

[Conventional technology]

The multi-directional multiplex communication system is designed for efficient communication between a single master station and multiple slave stations that are geographically scattered. information is time division multiplexed (TDM: Time Division M).
multiplex) and then transmitted. Each slave station separates and selects and extracts the information that is its own target. On the other hand, time division multiple access (TDMA) is used in which predetermined information is transmitted as a burst signal from each slave station to the master station only during a predetermined time slot assigned to each slave station.
The master station separates and outputs the information from each slave station.

In this system, the equipment at the master station is common to the line between each slave station, so a failure in the equipment at the master station will cause a failure in all lines, so the equipment at the master station is A redundant configuration with spares is in place. In the case of the above TDMA system, in the case of the Briassign method in which a transmission time slot is assigned to each slave station in advance, a transmission path corresponding to the said time slot is always formed between the master station and each slave station. There is. Therefore, in order to monitor equipment failures in the master station, switching to the standby system can be controlled by constantly monitoring these transmission lines and detecting transmission line failures with all slave stations.

A conventional device monitoring and switching control system of a master station will be explained with reference to FIGS. 3 and 4. Transmission information 1a to 1 to each slave station
n is a TD signal whose speed is converted by the channel processing circuits 106a to 106n from an input continuous signal to a predetermined time period (hereinafter referred to as a channel) on a prespecified TDM frame.
The active transmitter 10 is connected to the M signal 2 and 1 branch circuit 105.
0. The signals are respectively input to the preliminary transmitter 100'. In each transmitter, a frame synchronization signal is generated by the baseband processing circuits 101 and 101'.

Line monitoring signals and the like are multiplexed to produce baseband TDM frame signals 4, 4' shown in FIG. 4(A).

These baseband TDM frame signals 4°4' are sent to the modulator 102. '102', the transmitting circuit 10
3, 103' converts the signal into a predetermined frequency. The outputs 6 and 61 of the transmitting circuits 103 and 103' are selected as normal by the transmitting switching circuit 104, and are transmitted to each slave station as a transmitter cuff.

On the other hand, the received signal 15 from each slave station is a burst signal of each slave station as shown in FIG. The signal is input to the preliminary receiving section 200'.

In each receiving section, the signals 14 and 14' branched into two are subjected to frequency conversion by receiving circuits 203 and 203', respectively, and then demodulated by demodulating circuits 202 and 202'. These demodulated signals 12.degree.12/ are separated into line monitoring signals and the like by reception baseband processing circuits 201 and 201', and the normal side is selected by reception switching circuit 205. Each channel processing circuit 2068-206n separates the corresponding channel signal, converts the speed thereof, and outputs received signals 10a-10n, respectively.

In this system, especially regarding failure monitoring of the receiving sections 200 and 200', the received signal is a burst signal as shown in Fig. 4, and since each slave station is geographically scattered, the received electric field is Each burst is different. Therefore, a limiter amplifier is usually used to keep the input level of the demodulators 202, 202' constant. For this reason, even if an attempt is made to monitor reception system failures using the input level of the demodulator, it will not be possible to distinguish whether the input is a normal burst signal or mere thermal noise, and the accuracy will not be sufficient. For this reason, normally, a monitoring bit is added by performing a integrity check on the information signal on the transmitting side for each burst. On the receiving side, a reception baseband processing circuit monitors them, and when the error rate of all channels exceeds a certain threshold, it is determined that there is a reception failure, and a reception alarm 18 or 18' is sent to the alarm control circuit 300. Switching control was performed by sending switching signals 17 to the normal side to the transmission and reception switching circuits, respectively.

[Problem to be solved by the invention]

The above-mentioned reception system failure monitoring method is based on the glia assignment method in which a transmission time slot is assigned to each slave station in advance.
The fact that signals from each station are always correctly received can be the basis for determining that the receiving system equipment is normal. However, in the demand assignment method, in order to increase the efficiency of wireless circuit usage, transmission of information is stopped while it is not needed, and a transmission request is made to the master station only when it is needed. Have the user specify a channel, use that channel, and occupy that channel only for as long as necessary.

For this reason, the radio channel used is not always constant and changes from moment to moment, and depending on the time of day, there may be a state in which there is no received signal from the master station because all the slave stations do not need to transmit. On the other hand, the above-mentioned reception monitoring method requires radio channel occupancy information every two moments, and therefore has the drawback that monitoring cannot be performed at all when all slave stations are in a state where transmission is stopped.

[Means to solve the problem]

The present invention provides a multi-directional multiple communication system that uses a demand assignment method, in which a master station sequentially polls slave stations with test control commands via an information transmission channel, and the polled slave stations perform tests in accordance with the test control commands. The signal is sent through an information transmission channel, and the parent station is provided with means for separating and monitoring the test signal of Poko et al. It is characterized by controlling switching between active and standby at the station.

〔Example〕

The present invention will be described in detail with reference to FIGS. 1 and 2. In the demand assignment system, a channel CH-p and information channels CHa to CHn are prepared as shown in FIG. 2 to control incoming and outgoing call connections for each slave station. The transmission signal 1a%In to the slave station is the channel processing circuit 106
a'' 106 n is converted into a predetermined channel on the wireless TDM frame designated by n, and becomes TDM signal 2, which is transmitted by two branch circuits 105 to n active transmitting units 100 and 106, respectively.
The signal is input to the preliminary transmitter 100'. At this time, the control circuit 4
00, the polling call connection signals 8, 8' are input to the channel CH-p, and the test control commands 9, 9' are input to an arbitrary information channel, respectively. After TDM multiplexing, it is the same as before.

It undergoes modulation and frequency conversion and becomes the transmitter cuff. On the other hand, the reception system also performs frequency conversion and demodulation in the same manner as before, and the reception baseband processing circuits 201 and 201' receive signals sent from slave stations according to control channel signals 16 and 16' and test control commands 9 and 9'. The test signal 18.18' is separated,
At the same time as output to the control circuit 400, the reception switching circuit 20
5 to each channel processing circuit 206a-206n.

In this configuration, the control circuit 400 sequentially polls the slave stations belonging to its own station using the polling call connection signals 8 and 81, and also sends test control commands 9 and 9'. The slave station transmits test signal 18 according to test control commands 9 and 91.
, 18' to the master station via an arbitrary information channel. Therefore, the control circuit 400 of the master station monitors the test signals 18, 18' from the designated slave station, and when the test signal 18, 18' is received without error in both the working and standby systems, the slave station and the own station can be judged to be normal. Also, if only one of the active and standby terminals accepts that the test signal 18°18' is correct, the slave station is normal.

It can be determined that the erroneous side of the receiving system test signals 18 and 18' of the own station is a failure. Furthermore, if both the working and standby test signals are 18° and 18' erroneous, there is a possibility that there is a failure in the slave station or a simultaneous failure in both the working and standby stations. Depending on whether 18.18' is correct or incorrect, it is possible to determine whether the problem is the slave station or the own station.

These are summarized in Table 1.

Normally, the probability of simultaneous failures is sufficiently small, so if both failures occur, it can be determined that it is a failure of the slave station (4 in Table 1) or a transmission failure of the own station (5 in Table 1). Control circuit 400
transmits the switching control signal 17 based on this determination to the switching circuit 104. By performing transmission and switching to the reception switching port w1205, relatively easy and reliable failure detection is possible even in the demand assignment method.

〔Effect of the invention〕

As described above, the present invention sequentially polls each slave station using a test control signal using an information channel in order to monitor the presence or absence of a failure in each slave station that is not transmitting in the demand assignment method. However, since the slave station transmits the test signal to the master station using the information channel in accordance with the test control signal, the information channel can be used effectively in terms of time.

In addition, it is possible to monitor all slave stations based on whether the test signal is correct or not, and at the same time, it is possible to reliably and easily monitor failures in the own station, which has the effect of increasing the reliability of the entire system.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the basic configuration of the present invention, Fig. 2 is a diagram showing an example of the frame configuration of the present invention, Fig. 3 is a block diagram in the conventional Briassign system, and Fig. 4 is the case in that case. An example of the frame structure is shown below. 100, 101'... Transmitter (working/spare), 10
1゜101′...Transmission baseband processing circuit, 10
2,102'...Modulator, 103,103'...Transmission circuit, 1o4...Transmission switching circuit, 105...Branch circuit, 106...Transmission channel processing circuit, 201z
zor...reception baseband processing circuit, 202, 20
2'--Demodulator, 203, 203'--Receiving circuit,
204... Branch circuit, 205... Reception switching circuit, 2
06... Reception channel processing circuit, 300... Alarm control circuit, 40o... Control circuit. Figure 1 Second doctor 1 TDM frame -+
Slave station → R station (Black station receiving A: Q number N 4th figure calculation station - Lo station (J watching station receiving A Q number U)

Claims (1)

[Claims] 1. A demand system that is equipped with a predetermined master station and a plurality of slave stations corresponding to the master station, and that assigns a predetermined transmission channel to the slave station only when the slave station needs to transmit information.
In a multidirectional multiplex communication system that uses an assignment method, the master station sequentially polls slave stations with test control commands via an information transmission channel, and the polled slave stations transmit test signals according to the test control commands. The master station is equipped with means for separately monitoring these test signals in the working and standby systems, and depending on whether the test signals are correct or incorrect, - A multidirectional multiplex communication system characterized by performing backup switching control.