JPH01226231A - System for controlling demand-assigned multiple access - Google Patents

Abstract

PURPOSE:To avoid a state that the communication function of a whole system is lost by providing a present control earth station and a standby control earth station, both of which can centrally assign and control a communication channel through the use of the same common signal channel. CONSTITUTION:When a main DAMA(Demand-Assigned Multiple Access) controller 11 in the control earth station 1 detects that an abnormality occurs in a self DAMA centralized control function, it stops the action of a MODEM for CSC(common signal channel) 12. As a result, a main DAMA controller 11 in the control earth station 2 detects that the signal of a continuous mode from CSC is eliminated, starts the MODEM for CSC 12 after a prescribed time lapses and transmits the signal of the continuous mode to CSC. Next, it attains DAMA centralized control in place of DAMA controller 11 in the control earth station 1. Since the main DAMA controller 11 is substituted, the carrier frequency of CSC does not change and therefore, respective slave DAMA controllers 14 do not need to execute special processings with respect to the substitution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a demand-assigned multiple access control system, and more particularly to a centrally controlled demand-assigned multiple access in a 5CPC satellite communication system that uses a separate carrier for each call. Regarding control method.

[Conventional technology]

demand-assignment multiple access
In a satellite communication system that performs multiple access (hereinafter referred to as DAMA) using the 5CPC method, especially in such a small-scale satellite communication system, DAMA control is often performed intensively.

In the conventional request allocation multiple access control system, a satellite communication system is provided with one controlling earth station, and the main DAMA controller installed in this controlling earth station uses a common signal channel (common sign) using a dedicated carrier wave for DAMA control.
It has been common practice to perform DAMA control of each earth station (including the own station) via an aling channel (hereinafter referred to as C8C).

However, if there is only one controlling earth station, if this controlling earth station loses its DAMA centralized control function due to a natural disaster or the like, the entire satellite communication system will lose its communication function.

In order to solve this problem, two control earth stations were installed,
C8C also uses a separate C8C for each control earth station, and in the event of an abnormality, the control earth station that is currently operating will send a specific pattern of data to its own C8C, and the control earth station that is operating as a backup will send data to other C8Cs. It constantly monitors the C8C of a controlled earth station, and when it receives a specific pattern of data, it detects that an abnormal situation has occurred in another controlled earth station, and sends 2
.

A request allocation multiple access control system that performs DAMA control has been proposed.

[Problem to be solved by the invention]

The conventional request allocation multiple access control system in which two control earth stations are provided as described above uses two sets of C8Cs, and therefore has the disadvantage of poor frequency utilization efficiency.

The object of the present invention is to provide two control earth stations;
Moreover, it is an object of the present invention to provide a request allocation multiple access control system with good frequency utilization efficiency.

[Means to solve the problem]

The request allocation multiple access control system of the present invention centralizes allocation control to allocate a plurality of communication channels, each using a different carrier wave, in response to a call request, and uses a carrier wave different from any of the carrier waves used by each of the communication channels. an active request allocation main control device that receives the call request via a common signal channel using a common signal channel, constantly sends out a transmission wave containing the allocation result of the call channel to the common signal channel, and stops sending out the transmission wave when an abnormality occurs; and a working control earth station equipped with a working control earth station, and constantly monitoring the transmission wave sent out by the working request allocation main control device of the working control earth station, and if the transmission wave is not received for a predetermined period of time, the working request allocation main control device a preliminary control earth station comprising a preliminary request allocation main control device that performs the allocation control centrally on behalf of the common signal channel, receives the call request and sends the call channel allocation result; at least one transmitting/receiving device that is capable of tuning to both the speech channel and the common signal channel, and the transmitting/receiving device that is normally tuned to the common signal channel and is tuned to the common signal channel. a request allocation slave control device that transmits the call request and receives the call channel allocation result, and controls the tuning of the transmitting/receiving device to perform the call based on the received call channel allocation result.=
5- Equipped with multiple slave earth stations.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

The embodiment shown in FIG. 1 is comprised of control earth stations 1 and 2, a large number of slave earth stations 3 (only two stations are shown in FIG. 1), and a space station 4, each of which It uses bidirectional C8C and multiple communication channels relayed at the space station 4 using different carrier waves.

The control earth stations 1 and 2 have a main DAMA controller 11 and
A C8C modem 12 and a C8C monitor demodulator 13 connected to the main DAMA control device 11, a plurality of slave DAMA control devices 14, a pair of modems 15 connected to each slave DAMA device 14, and a C8C Modem/demodulator 1
2. C8C monitor demodulator 13 and each modem 1
5 and a shared wireless transmitter/receiver 16 connected to the wireless transmitter/receiver 16.

The control earth stations 1 and 2 are both configured to be able to function as a working control earth station or a backup control earth station,
While one operates as the active control earth station, the other operates as the backup control earth station. Main DA of active control earth station
The MA control device 11 is in active use and performs DA'MA centralized control, and the main DAMA control device 11 of the reserve control earth station is in reserve and performs backup operation for DAMA centralized control.

The C8C modulation/demodulation device 12 sends a continuous mode signal modulated with the data output by the main DAMA control device 11 to one direction of the C8C via the shared radio transceiver 16.
The burst mode signal received from the other direction of the C8C via the shared wireless transceiver 16 is demodulated, and the demodulated data is output to the main DAMA control device 11. Among the C8C modulation/demodulation devices 12, the one connected to the main DAMA control device 11 that is performing backup operation stops its operation.

The C8C monitor demodulator 13 is a shared wireless transceiver 16
The continuous mode signal received from the C8C via the C8C is demodulated and the demodulated data is output to the main DAMA control device 11.

The modem 15 transmits the C8 via the shared radio transceiver 16.
It is possible to send and receive both C and communication channels. however,
In C8C transmission/reception, the demodulation side performs reception and demodulation in the continuous mode direction and outputs the demodulated data to the slave DAMA control device 14, and the modulation side receives burst data modulated with data input from the slave DAM'A control device 14. Outputs the mode signal. The slave DAMA control 14 controls which channel the modulation/demodulation device 15 is tuned to.

Each slave earth station 3 has a slave DAMA control device 1 connected in sequence.
4. It is configured to include a modulation/demodulation device 15 and a wireless transceiver 31. The radio transceiver 31 is connected to the control earth station 1.2.
The shared radio transceiver 16 performs the same operations as the modem 15 in the .

The following description will be made assuming that the controlling earth station 1 becomes the active controlling earth station in the initial state.

In the initial state, the main DAMA controller 11 of the controlling earth station 1 operates the C8C modem 12, and the main DAMA controller 11 of the controlling earth station 2 operates the C8C modem 12.
In addition, each slave DAMA control device 14 of the controlling earth stations 1, 2 and each slave earth station 3 tunes the connected modem device 15 to C8C. As a result, a continuous mode signal is sent from the controlling earth station 1 to the C8C, and the main DAMA controller 11 of the controlling earth station 2
Confirm that the continuous mode signal is being sent to C.

When a call request is received from an outside line to one of the slave DAMA control devices 14, the slave DAMA control device 14
It outputs call request data including identification data of the call requestee, and this call request data is transferred to the main DAMA controller 11 of the controlling earth station 1 in burst mode via the C3C. The main DAMA control device 11 of the control earth station 1 stores the usage status of each call channel, allocates an unused call channel to the input call request data, and uses the allocated call channel and call request source 1 call request. The allocation data including the previous identification data is output, and the stored contents of the usage status of each communication channel are updated based on this allocation. The allocation data is transferred to each slave DAMA controller 14 in continuous mode via the C8C. The slave DAMA control devices 14 of the call request source and the call request destination specified by the allocation data tune the respective connected modem devices 15 to the specified communication channels, and connect these modem devices 15 to the corresponding outside lines. , now you can make a call. When the call is completed, the bi-liquid demodulator 15 used for the call is disconnected from the outside line controlled by the slave DAMA controller 14 and tuned to C8C,
Either slave DAMA control device 14 notifies the main DAMA control device 11 of the controlling earth station 1 of the completion of the call, and the main DAMA control device 11 that receives this notification updates the stored contents of the usage status of each call channel. , outputs allocation release data including identification data of the released communication channel.

During this time, the main DAMA control device 11 of the control earth station 2
Backup for storing and updating the usage status of each communication channel using the allocation data and allocation release data input from the 8C monitor demodulator 13 so that it matches that performed by the main DAMA controller 11 of the control earth station 1. perform an action.

Now, when the main DAMA control device 11 of the control earth station 1 detects that an abnormality has occurred in its own DAMA centralized control function, it stops the operation of the C8C modem device 12. As a result, the main DAMA controller 11 of the controlling earth station 2
Detects that the continuous mode signal from 8C is gone,
After a certain period of time has elapsed, the C8C modem 12 is started and the C8C mode is activated.
A continuous mode signal is sent to 8C, and DAMA centralized control is performed in place of the main DAMA control device 11 of the control earth station 1.

Even if the main DAMA control device 11 that performs DAMA centralized control is replaced in this way, the C8C carrier frequency does not change, so each slave DAMA control device 14 does not need to take any special measures for this replacement. .

After the DAMA centralized control is transferred to the main DAMA control device 11 of the controlling earth station 2 as explained above, the controlling earth station 1
When the abnormality is recovered by maintenance work, the usage status of each communication channel stored in the main DAMA controller 11 of the controlling earth station 2 is changed to the main DA of the controlling earth station 1 in continuous mode of C8C.
It is transferred (manually) to the MA control device 11, and thereafter the main DAMA control device 11 of the controlling earth station 1 performs a backup operation.

The operation of the embodiment shown in FIG. 1 has been described above.

Note that one of the control earth stations 1 and 2 is the active control earth station,
If the other earth station is fixed as a backup earth station, there is no need to provide the C8C monitor demodulator 13 to the currently controlled earth station. In this case, if an abnormality occurs in the active control earth station and the abnormality of the active control earth station recovers while the backup control earth station is performing DAMA centralized control, the DAMA centralized control can be transferred from the backup control earth station to the active control earth station by manual operation. Transfer to control earth station.

In addition, since the C8C modem 12 and the C8C monitor demodulator do not need to operate simultaneously (in the same station), the demodulator of the C8C modem 12 can be tuned in both C8C directions, and in continuous mode and burst mode. If the C8C monitor demodulator 13 is enabled to operate in both modes and the switching between these modes is performed by the main DAMA control device 11, it is not necessary to separately provide the C8C monitor demodulator 13.

〔Effect of the invention〕

As explained above, the present invention is equipped with an active control earth station and a standby control earth station that can centrally control the allocation of communication channels using the same common signal channel, and the active control earth station is equipped with a common signal channel. By stopping transmitting waves to the channel and transferring the allocation control from the active control earth station to the standby control earth station, even if one control earth station loses its allocation control function due to a natural disaster, etc. It is possible to avoid a situation where the communication function of the entire communication system is lost, and
This has the effect of not deteriorating frequency usage efficiency.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. =13- 1.2... Control earth station, 3... Subordinate earth station, 4... Space station, 11... Main DAM
A control device, 12... C8C modem device, 1
3... River/cSc monitor demodulator, 14... Slave DAMA control device, 15... River/modulator/demodulator, 16...
. . . Shared wireless transceiver, 31 . . . Wireless transceiver. Agent Patent Attorney Oto Uchihara 1 mouth

Claims (1)

[Claims] A common signal channel that centrally performs allocation control to allocate a plurality of communication channels each using a different carrier wave according to a call request, and uses a carrier wave different from any of the carrier waves used by each of the communication channels. a working control device comprising a working request allocation main control device that receives the call request through the communication channel, constantly sends out a transmission wave containing the call channel allocation result to the common signal channel, and stops sending out the transmission wave when an abnormality occurs. The earth station and the active request allocation main controller of this active control earth station constantly monitor the transmitted waves sent out, and if the transmitted waves are not received for a predetermined period of time, the active request allocation is performed in place of the main controller. a preliminary control earth station comprising a preliminary request allocation main controller that centrally performs the allocation control and receives the call requests and sends the communication channel allocation results via the common signal channel; the call request via at least one transceiver device that is tuned to any of the common signal channels, and the transceiver device that is normally tuned to the common signal channel and is tuned to the common signal channel; a plurality of slave earth stations comprising: a request allocation slave control device that transmits the communication channel allocation result and receives the communication channel allocation result, and controls the tuning of the transmitting/receiving device to conduct a communication based on the received communication channel allocation result; A request allocation multiple access control method characterized by comprising the following.