JPH05206911A - Small earth station - Google Patents

Abstract

PURPOSE:To surely execute a termination processing when battery voltage drops while slave stations operated by battery power make a call. CONSTITUTION:Input impression voltage monitor parts 17 in the both slave stations monitor the level of voltage supplied from battery power. When it drops to less than a specified value, a voltage level drop detection signal is transmitted to control parts 7. The control parts 7 receive the voltage level drop detection signal, cause alarm sound oscillation parts 18 to output alarm sound, light alarm lamps 19 and inform the operator of the relevant small earth station of the drop of power voltage. At the same time, the control parts 7 drop a carrier transmission level transmitted from modulator-demodulators 9 to a specified level which does not become an obstacle on operating a line. Thus, the power consumption of a battery is reduced, the call until a transmission/reception function becomes abnormal from the occurrence of alarm becomes possible and the termination processing such as the notice of effect that the call cannot be made before long to the opposite station can be executed during that time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small earth station as a slave station in a satellite communication system in which slave stations communicate with each other through a satellite at a pair of transmission and reception frequencies allocated by a demand assignment method, and more particularly to a battery. The present invention relates to a portable small earth station which can be operated by a power source.

[0002]

2. Description of the Related Art In satellite communication systems, various communication systems such as FDMA (frequency division multiple access) system and TDMA (time division multiple access) system are adopted.
The method is a method of allocating one carrier to one voice channel, which is generally an SCPC.
It is called a (Single Channel Per Carrier) system and is used in a satellite communication system composed of a large number of earth stations with a small amount of communication. And, the satellite communication system adopting the SCPC method is required to improve the utilization efficiency of the line by demand assignment (DAMA: Demand Assignment).
It is operated by the Multiple Access method.

The DAMA method is an allocation request multiple access method, in which a master station that manages the frequency of a communication satellite line pools a fixed number of lines commonly for each earth station (slave station). This is a line allocation method in which each time a call occurs, a pair of frequencies for transmission and reception in the common pool are allocated to it, the allocation is canceled upon receiving the end notification from the slave station, and the line is returned to the pool. In this method, the master station only controls the line connection,
The usage status of the allocated line is not monitored. Less than,
An outline of a conventional satellite communication system adopting the SCPC method will be described with reference to FIG.

In FIG. 2, a large number of slave stations (21, 22,
......) are terminals 1 such as telephones and facsimiles.
0, which is connected via a satellite 4 to a master station 3 which performs line allocation control by the DAMA method. The satellite line is the line for communication 1
4 and a control line (CSC channel) 15. Connection of the communication path between the slave stations 21 and 22 is performed by the following procedure.

In the slave station 21, when the off-hook of the terminal 10 is detected by the call detecting circuit 16, the control section 20 sets the frequency of the tuning circuit 8 to the frequency of the control line 15, and the modulator / demodulator 9 controls the slave station. A connection request having the content of connection with 22 is sent to the control line 15.

In the master station 3, the tuning circuit 35 uses the control circuit 1
Since the frequency is set to 5, the connection request sent to the control line 15 is demodulated by the modulator / demodulator 33 and the control unit 3
It is transmitted to 1. The control unit 31 determines the line (call line 14) used by the slave stations 21 and 22, that is, allocates a pair of frequencies for transmission and reception used in the call line 14, and calls the slave stations 21 and 22 for communication. The control signal 12 having the contents such as switching to transmission / reception on the line 14 is formed and sent from the modulator / demodulator 33 to the control line 15.

In the slave stations 21 and 22, the control signal 12 sent to the control line 15 is demodulated by the modulator / demodulator 9 and input to the controller 20. The control unit 20 sets the frequency of the tuning circuit 8 to a predetermined transmission / reception frequency according to the content of the control signal 12. As a result, call connection is established, and a call (voice call signal 11) between both slave stations is started.

By the way, as is clear from the above description, when a call is started between the slave stations, the master station 3 becomes the slave station 21.
And 22 are disconnected from the communication line 14 used.
Therefore, the master station 3 cannot directly monitor whether the communication line 14 used by the slave stations 21 and 22 is still in use or normal.

Therefore, in each slave station, the call detection circuit 16 monitors whether or not the call continues, and when the call ends, the control unit 20 sets the frequency of the tuning circuit 8 to the frequency of the control line 15 to ensure normal operation. The control signal 12 having the content of the end is sent to the master station 3. As a result, the master station 3 cancels the allocated pair of transmission and reception frequencies and returns the line to the pool.

Also, in each slave station, the control unit 2
0 controls the voice band out-of-band oscillator 5 to generate the voice band out-of-band signal 13 at a predetermined time interval. This is a burst signal and is sent to the partner slave station via the line 14 in communication.
In the partner station, the out-of-band signal receiver 6 processes the burst signal and sends it to the control unit 20 to confirm whether or not the burst signal is normally received.

That is, both slave stations send and receive burst signals during the call period to monitor the line status. When an abnormality occurs in the transmission / reception of the burst signal, the control unit 20 in both slave stations recognizes the poor line connection, sets the frequency of the tuning circuit 8 to the frequency of the control line 15, and controls the abnormal termination. The signal 12 is sent to the master station 3. This makes the master station 3
Releases the assigned pair of transmission and reception frequencies and returns the line to the pool.

As described above, the master station 3 cannot directly monitor the state of the allocated line, but only indirectly.

[0013]

Then, there is the following problem in the system in which the small earth station includes a portable small earth station which can be operated by a battery power source. In other words, when the slave stations operating on battery power are talking to each other and the battery power of both stations is exhausted and normal transmission / reception operations cannot be performed, the master station cannot notify the master station of abnormal termination, so the master station cannot There is a problem that the abnormal termination of the call connection between the stations cannot be recognized and the assigned line cannot be returned to the common pool.

An object of the present invention is, in a portable small earth station that operates even with a battery power source, reliably perform a call termination process before an abnormality occurs in transmission / reception operation due to exhaustion of the battery power source.
It is to provide a small earth station capable of notifying a master station of abnormal termination.

[0015]

In order to achieve the above object, the small earth station of the present invention has the following configuration. That is, the small earth station of the first invention is a satellite communication system in which slave stations communicate with each other through a satellite line composed of a pair of transmission / reception frequencies allocated by the demand assignment method; The earth station includes an input applied voltage monitoring unit; an alarm sound oscillator and / or an alarm lamp; and a warning sound to the alarm sound oscillator upon receipt of a voltage level drop detection signal output from the input applied voltage monitor. Is output and / or the alarm lamp is turned on, and a control means for lowering the carrier wave transmission level to a prescribed level that does not hinder the line operation is provided. It is a thing.

The small earth station of the second invention is a satellite communication system in which the slave stations communicate with each other by a satellite line composed of a pair of transmission and reception frequencies allocated by the demand assignment method; The small earth station has an input applied voltage monitoring unit; and / or an alarm sound oscillator and an alarm lamp; upon receiving a voltage level detection signal output from the input applied voltage monitoring unit, the detected voltage level is below a specified value. When the alarm sound is generated, an alarm sound is output to the alarm sound oscillating unit and / or the alarm lamp is turned on, and the carrier transmission level is lowered to a specified level that does not cause an obstacle in line operation. And that the detected voltage level reaches the level that causes abnormalities in the transmission / reception function to notify the master station of abnormal termination. It is characterized in further comprising a; control means and performing and.

[0017]

Next, the operation of the small earth station of the present invention configured as described above will be described. According to the first aspect of the present invention, an input applied voltage monitoring unit is provided in a small earth station that is a slave station that can be operated by a battery power source,
An alarm sound oscillator and / or an alarm lamp are provided, and when the battery power supply voltage drops below a specified value, the operator of the small earth station is notified by an alarm sound and / or the lighting of the alarm lamp. To do. Then, the carrier transmission level is lowered to a prescribed level that does not cause an obstacle in line operation, power consumption is reduced, and the call time with the partner slave station is extended. As a result, it is possible to perform termination processing such as notification to the other station of the other party that a telephone call will soon be unavailable. Since the notification to the master station will be given after starting up with a new battery, it takes some time, but the master station can surely perform the line control.

In the second invention, in addition to the first invention,
Since the master station is notified of the abnormal end before the battery voltage reaches the level at which the transmission / reception function is abnormal, the master station receives the abnormal end notification at approximately the same time as the end of the call between the slave stations. Therefore, the reliability of line control can be further enhanced.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a satellite communication system including a small earth station according to an embodiment of the present invention. The same components as those of the conventional device (FIG. 2) are designated by the same reference numerals. In FIG. 1, the slave stations 1 and 2 are portable small-sized earth stations that operate on battery power, although their power sources are not shown. They include an input applied voltage monitoring section 17, an alarm sound oscillating section 18, and an alarm lamp 19. And are added, and some functions are added to the control unit 7. Less than,
The part relating to the present invention will be mainly described.

The input applied voltage monitoring section 17 of both slave stations monitors the level of the voltage supplied from the battery power source, and when it falls below a specified value, sends a voltage level drop detection signal to the control section 7.

Upon receipt of the voltage level drop detection signal, the control unit 7 causes the alarm sound oscillation unit 18 to output an alarm sound and turns on the alarm lamp 19. As a result, the operator of the small earth station can know the decrease in the power supply voltage. Therefore,
Either one of the alarm sound oscillating unit 18 and the alarm lamp 19 may be provided, but if both are provided, the operator can be surely notified.

Then, in parallel with the above operation, the control unit 7 lowers the carrier transmission level sent from the modulator / demodulator 9 to a prescribed level that does not cause an obstacle in line operation. Normally, the transmission level in satellite line operation is set with a certain margin, so a level decrease of several decibels does not hinder the line operation. As a result, the power consumption of the battery is reduced, and it becomes possible to talk from the alarm occurrence until the transmission / reception function becomes abnormal, and during this time, it is possible to perform termination processing such as notification to the other party's slave station that communication will eventually become impossible. Becomes

With the above configuration, since the notification to the master station is performed after starting up with a new battery, it takes some time, but the master station can surely perform the line control.
The problem as in the past does not occur.

In order to promptly notify the master station, the control section 7 monitors the voltage level detection signal output from the input applied voltage monitoring section 17 and warns when the detected voltage level becomes below a specified value. An alarm sound is output to the sound oscillating unit 18, an alarm lamp 19 is turned on, the carrier wave transmission level is lowered to a prescribed level that does not cause an obstacle in line operation, and the detected voltage level is a level that causes an abnormality in the transmission / reception function. The master station should be notified of the abnormal termination before reaching. According to this, the reliability of line control can be further enhanced.

[0025]

As described above, according to the small earth station of the present invention, in the first invention, the small earth station which is the slave station which can be operated by the battery power source is provided with the input applied voltage monitoring section and the alarm sound oscillation. And / or an alarm lamp is provided, and when the battery power supply voltage drops below a specified value, the operator of the small earth station is notified by an alarm sound and / or the lighting of the alarm lamp. Then, the carrier transmission level is lowered to a prescribed level that does not cause an obstacle in line operation, power consumption is reduced, and the call time with the partner slave station is extended. As a result, termination processing such as notification to the other party's slave station that communication will not be possible soon can be performed, and notification to the master station will be performed after starting up with a new battery,
Although it takes some time, the master station has the effect of surely controlling the line.

In the second invention, in addition to the first invention,
Since the master station notifies the master station of abnormal termination before the battery voltage reaches the level at which abnormal transmission / reception functions occur, the master station can receive the abnormal termination notification at approximately the same time as the call termination between the slave stations. The effect is that the reliability of line control can be further enhanced.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of a satellite communication system including a small earth station according to an embodiment of the present invention.

FIG. 2 is a configuration block diagram of a satellite communication system including a conventional small earth station.

[Explanation of symbols]

 1 Slave station 2 Slave station 3 Master station 4 Satellite 7 Control unit 17 Input applied voltage monitoring unit 18 Alarm sound oscillation unit 19 Alarm lamp

Claims (2)

[Claims] 1. A satellite communication system in which slave stations communicate with each other through a satellite line composed of a pair of transmission and reception frequencies allocated by a demand assignment method; A voltage monitoring unit; and / or an alarm sound oscillator and / or an alarm lamp; receiving a voltage level drop detection signal output from the input applied voltage monitor and causing the alarm sound oscillator to output an alarm sound; A small earth station characterized by comprising: a control means for turning on an alarm lamp or both, and for lowering a carrier wave transmission level to a prescribed level that does not hinder the line operation. 2. A satellite communication system in which slave stations communicate with each other through a satellite line composed of a pair of transmission and reception frequencies assigned by the demand assignment method; A voltage monitoring unit; an alarm sound oscillator and / or an alarm lamp; and when the voltage level detection signal output from the input applied voltage monitoring unit is received and the detected voltage level falls below a specified value, the alarm sound Outputting an alarm sound to the oscillator and / or turning on the alarm lamp, and lowering the carrier transmission level to a specified level that does not hinder the line operation, and its detected voltage level. Control means for causing the master station to notify the master station of an abnormal end before reaching a level at which an abnormal transmission / reception function occurs. A small earth station characterized by having it.