JPH0591007A - Satellite communication system - Google Patents

Abstract

(57) [Summary] [Object] To provide a method for forcibly disconnecting an individual communication path once set in a DAMA system used for satellite communication with a simple slave station configuration. [Structure] A forced disconnection command signal is repeatedly broadcast from a master station with a carrier wave f _R ′ of a preset frequency, while
At the slave station, voice burst 1 transmitted by voice activation with the individual communication carrier set by DAMA 1
This instruction is decoded by utilizing the interval of 8 and switching to the frequency f _R ′ of the forced disconnection instruction for a short time immediately after the end of the voice burst. Therefore, only one slave station demodulator is required.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite communication system, and more particularly to a demand allocation multiple access system (DemandAssignment).
It is related to the improvement of the forced disconnection procedure in Multiple Access (DAMA).

[0002]

2. Description of the Related Art FIG. 10 shows a request allocation multiple access system (Dema).
FIG. 1 is a diagram showing a configuration of a conventional satellite communication system using ND Assignment Multiple Access (DAMA), in which 1 is a satellite, 2 and 3 are slave stations, 4 is a master station, 5 is an individual slave station. A communication line, 6 is a control line between the slave station and the master station.
FIG. 11 is a diagram showing a simple configuration of a slave station. In the figure, 7 is an antenna, 8 is a high power transmitter, 9 is a transmission frequency converter, 10 is a modulator, 11 is a low noise receiver, 12 Is a reception frequency converter, 13 and 14 are demodulators, 15 is a transmission input, 16 is a reception output, and 17 is a forced disconnection command output.

Next, FIG. 12 is a diagram showing a carrier wave used in this satellite communication system. In the figure, f _R is a control line from a master station to a slave station, which is generally a channel control line (downlink). ), F _C is a control line for sending connection requests, release requests, etc. from a plurality of slave stations in the system to the master station, and is called a channel control line (uplink),
f _R ′ is a control line sent from the master station to the slave station for forced disconnection, and f ₁ and f ₂ are carrier waves for individual communication assigned by the master station in response to a connection request from the slave station. Figure 1
3, FIG. 14 is a diagram showing a procedure for connecting and disconnecting the above f ₁ and f ₂ .

Next, the operation will be described. The DAMA system is a system in which an individual communication path between the slave stations is set each time in response to a connection request from the slave station, and as shown in FIG. 13, for example, from the slave station A to the channel control line (uplink) f.
_{Using C} , the master station R is requested to set an individual communication path.
The master station R searches for two vacant carriers (for example, f ₁ and f _{2 in} FIG. 12) from the frequency resources managed by the master station R, and uses the channel control line (downlink) f _R to search for the slave station A. Then, the slave station B is instructed about carrier frequencies f ₁ (f ₂ ) and f ₂ (f ₁ ) to be transmitted (received) by the slave station. The slave station uses the commanded frequency to set a bidirectional communication path between the two stations so that a call can be made. After the end of the call, both slave stations stop transmitting the carriers of f ₁ and f ₂ , and again notify the master station R of the end of communication using the channel control line (uplink) f _C. In response to this, the master station returns f ₁ and f ₂ to the frequency resources managed by the master station, and sends an end confirmation signal to the slave station using the channel control line (downlink) f _R.

This will be described with reference to FIG. The connection request is sent through the transmitter input 15 from the sender (eg, slave station A).
It is transmitted to the modulator 10. This modulator 10 is preset so that the carrier frequency becomes f _C , and the connection request signal is converted to a high frequency on the satellite line by the transmission frequency converter 9, amplified by the high power transmitter 8 and then amplified by the antenna 7. From the satellite. On the other hand, the control signal from the master station R amplifies a weak signal from the satellite by the low noise amplifier 11 and converts it into a frequency suitable for the operation of the demodulator 13 by the reception frequency converter 12. The demodulator 13 is preset so as to be suitable for receiving f _R as its reception frequency, and the allocated frequencies f ₁ (for example, transmission frequency), f ₂ ( For example, the reception frequency) can be decoded. In accordance therewith, the transmission frequency of the modulator 10 is changed from f _C to f ₁ , the reception frequency of the demodulator 13 is changed from f _R to f ₂ , and the slave station B, which is a communication partner, also handles this. By performing the setting in the same procedure, slave station A and slave station B
A call can be made between the respective transmission input 15 and reception output 16 of the above.

Next, in such a DAMA system, when an emergency call request is newly made when all satellite frequency resources are used by each slave station, the individual communication paths already used are It is necessary to forcibly disconnect one. In order to enable this, the master station R can separately send a disconnection command to any slave station on the carrier wave f _R ′, as shown in FIG.

The disconnection command included in this carrier wave is shown in FIG.
When it is received by the demodulator 14 shown in FIG. 2 and is instructed to disconnect the individual communication path of the slave station, the transmission carrier is sent to the modulator 10 via the disconnect control output 17 of the demodulator 14. It is possible to turn it off. This state is shown in FIG. In FIG. 14, the procedure is the same as that in FIG. 13 until the individual communication path is set by the f ₁ and f ₂ between the slave station A and the slave station B, but is forcibly disconnected from the master station R by f _R ′ during communication. It shows how a command is sent.

[0008]

Since the conventional DAMA system is constructed as described above, an extra demodulator for always receiving the forced disconnection command in the slave station for the forced disconnection is required. There was a problem.

The present invention has been made in order to solve the above problems, and an object thereof is to obtain a satellite communication system in which a demodulator for a forced disconnection command signal as described above is unnecessary in a slave station. I am trying.

[0010]

The satellite communication system according to the present invention utilizes the fact that an individual communication carrier is stopped when there is no voice, and during this period, an intermittent forced disconnection command line can be received for a short time. It enables you to do it.

Further, the satellite communication system according to the present invention utilizes the fact that the individual communication carrier wave is stopped when there is no voice, so that the continuous forced disconnection command line can be received for a short time during this period. is there.

Further, the satellite communication system according to the present invention makes use of the fact that the individual communication carrier wave is stopped when there is no voice, so that the intermittent forced disconnection command line can be received for a short period of time. And in order to perform this forced disconnection as quickly as possible, when the silent period continues for a certain period of time, a pseudo voice burst is sent from the slave station,
This is to give a timing for switching the demodulator of the partner slave station to the forced disconnection command carrier wave.

Further, the satellite communication system according to the present invention makes use of the fact that the individual communication carrier wave is stopped when there is no voice, so that the continuous forced disconnection command line can be received for a short period of time. And in order to perform this forced disconnection as quickly as possible, when the silent period continues for a certain period of time, a pseudo voice burst is sent from the slave station,
This is to give a timing for switching the demodulator of the partner slave station to the forced disconnection command carrier wave.

Further, in the satellite communication system according to the present invention, in the intermittent individual communication signals between the slave stations, a signal section (hereinafter referred to as a pause section) which is insignificant for the individual communication is provided at a constant cycle, and the slave station The demodulator switches and receives the forced disconnection command line continuously transmitted by the master station during the idle period.

Further, in the satellite communication system according to the present invention, a signal section (hereinafter referred to as a pause section) which is not significant for individual communication is provided in a fixed cycle in intermittent individual communication signals between the slave stations, The demodulator switches and receives the forced disconnection command line continuously transmitted by the master station during the idle period.

[0016]

In the present invention, the fact that the individual communication carrier wave is stopped when there is no voice is utilized so that the intermittent forced disconnection command line can be received for a short period of time. This is achieved by switching the reception frequency of one demodulator to the individual communication carrier wave and the forced disconnection command carrier wave in time.

Further, in the invention, the fact that the individual communication carrier wave is stopped when there is no voice is utilized, and the continuous forced disconnection command line can be received for a short period of time during this period, so that the forced disconnection is performed. This is achieved by switching the reception frequency of one demodulator to the individual communication carrier wave and the forced disconnection command carrier wave in time.

Further, in the present invention, the fact that the individual communication carrier wave is stopped when there is no voice is utilized to enable the intermittent forced disconnection command line to be received for a short period of time, and this In order to perform forced disconnection as quickly as possible, when the silent period continues for a certain period or more, a pseudo voice burst is sent from the slave station to give a timing to switch the demodulator of the partner slave station to the forced disconnect command carrier wave. Forced disconnection is achieved by switching the reception frequency of one demodulator to the individual communication carrier and the forced disconnection command carrier in time, and even if the interval between voice bursts is long, the disconnection can be done quickly. ..

Further, in the present invention, the fact that the individual communication carrier wave is stopped when there is no voice is utilized so that the continuous forced disconnection command line can be received for a short time during this period, and In order to perform forced disconnection as quickly as possible, when the silent period continues for a certain period or more, a pseudo voice burst is sent from the slave station to give a timing to switch the demodulator of the other slave station to the forced disconnect command carrier wave. The forced disconnection is achieved by switching the reception frequency of one demodulator to the individual communication carrier wave and the forced disconnection command carrier wave in time, and even if the interval of the voice burst becomes long, the disconnection is promptly performed. You can do it.

Further, in the present invention, a signal section (hereinafter referred to as a pause section) which is insignificant for individual communication is provided at a constant cycle in the intermittent individual communication signal between the slave stations, and the slave station demodulator During the idle period, the master station continuously switches and receives the forced disconnection command line that is sent by the master station.Therefore, the forced disconnection forcefully disconnects the reception frequency of one demodulator from the individual communication carrier wave in time. This is achieved by switching to the command carrier wave.

In the satellite communication system according to the present invention, in the intermittent individual communication signals between the slave stations, a signal section (hereinafter referred to as a pause section) which is insignificant to the individual communication is provided at a constant cycle, and the slave station The demodulator is designed to switch and receive the forced disconnection command line continuously transmitted by the master station during the idle period, so that the forced disconnection allows the reception frequency of one demodulator to be individually communicated in time. This is achieved by switching the carrier wave and the forced disconnection command carrier wave.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below. 1 is a diagram showing a communication control system of a satellite communication system according to a first embodiment of the present invention. In the figure, 18
Is a voice-modulated carrier wave transmitted from the child station, 19
Is a preamble, 20 is voice data, 21 is a forced disconnection command data transmitted from the master station, and 22 is a forced disconnection command signal received by the slave station. FIG. 2 is a diagram showing a simple configuration of a slave station when the communication system according to the first embodiment of the present invention is applied.

Next, the operation will be described. FIG. 1 (a) shows a modulated wave transmitted from a slave station at a carrier frequency f ₁ , for example, on the time axis. Generally, the time when voice actually exists at the transmission input 15 shown in FIG. Only modulator 1
The output of 0 is controlled to appear. This is called voice activation, which is a known technique.

Therefore, as shown in FIG. 1 (a), the modulated wave is not continuous but is intermittently transmitted to the satellite. Each of these is called a voice burst 18, and the length of the voice burst is 1 to 2 for normal voice.
Seconds are normal. The contents of the voice burst 18 are provided with fixed data at the head thereof so that when the demodulator 13 of the opposite slave station receives this modulated wave, the demodulator can quickly establish a reception cycle. This is called the preamble 19. Then, the voice data (encoded voice) in the part (A ₁ and A ₂ ) indicated by 20
Is transmitted.

FIG. 1B shows a forced disconnection command signal transmitted from the master station at, for example, the carrier frequency f _R ′, and the command signal is shown at 21 in FIG. It is transmitted as data. The content of the data R is an identification code of the slave station which is the target of the forced disconnection, and is repeatedly transmitted as shown in FIG.

FIG. 1 (c) shows the contents of the carrier to be demodulated by the slave station demodulator 13 shown in FIG.
As shown in FIG. 6D, the individual communication carrier f ₁ transmitted from the opposite station is normally demodulated, but immediately after the end of reception of the burst is detected, the demodulation frequency of the demodulator 13 is set to f. Switch to _R '.

As a result, the forced disconnection signal 22 transmitted from the master station is demodulated, and thus the forced disconnection command R is decoded. If the content of R is directed to the own station, the transmission of the own station is immediately stopped. This is accomplished by turning off the output of modulator 10. Otherwise, the reception frequency of the demodulator is set to f ₁ again immediately after receiving one signal block 22 from the master station, and the individual communication path is maintained. Here, the setting of the frequency can be easily performed by a known frequency synthesizer included in the demodulator. The detection of the end of burst can be performed by the demodulator 13 itself by a known technique such as detection of received power or addition of a code indicating the end.

As described above, in the above embodiment, the extra demodulator for always receiving the forced disconnection command in the slave station for the forced disconnection is unnecessary.

In the above embodiment, an example of sending a burst wave as the forced disconnection command signal sent from the master station R is shown. However, this is similar to the second embodiment of the present invention shown in FIG. It may be continuous, and in the second embodiment, since the transmission density of the command signal is high, in addition to the effect of the above embodiment, there is an effect that the interval between successive voice bursts can be shortened.

Next, a third embodiment of the present invention will be described. FIG. 4 is a diagram showing a communication control system of a satellite communication system according to a third embodiment of the present invention. In the figure,
Reference numeral 118 is a burst modulated by the voice transmitted from the slave station, 119 is a preamble, 120 is voice data, and 12
1 is a forced disconnection command data transmitted from the master station, 122 is a forced disconnection command signal received by the slave station, 123 is a pseudo voice burst transmitted from the slave station, and 124 is a pseudo voice indicating a pseudo voice burst. Identification data part, 12
5 is the time T ₁ from the end of the actual voice burst to the start of the pseudo voice burst transmission, and 126 is the interval T ₂ between voice bursts. FIG. 5 is a simple block diagram of the slave station when the communication system according to the third embodiment of the present invention is applied.

Next, the operation will be described. FIG. 4 (a) is a time-axis view of a modulated wave transmitted from a slave station at a carrier frequency f ₁ , for example, the time when voice actually exists at the transmission input 15 shown in FIG. Only modulator 1
The output of 0 is controlled to appear. This is called voice activation, which is a known technique.

Therefore, as shown in FIG. 4 (a), the modulated wave is not continuous but is intermittently transmitted to the satellite. Each of these is called a voice burst, and the length of the voice burst is usually about 1 to 2 seconds for normal voice. The contents of the voice burst 118 are provided with fixed data at the head thereof so that when the demodulator 13 of the opposite slave station receives this modulated wave, the demodulator can quickly establish reception synchronization. This is called the preamble 119. The part indicated by 120 (A
Audio data (encoded audio) is transmitted by ₁ and A ₂ ).

FIG. 4 (b) shows a forced disconnection command signal transmitted from the master station at, for example, the carrier frequency f _R ′. Is transmitted as. The contents of the data R are repeatedly transmitted as shown in the figure by the identification code of the slave station which is the target of the forced disconnection.

FIG. 4C shows the contents of the carrier to be demodulated by the slave station demodulator 13 shown in FIG.
As shown in FIG. 3D, the individual communication carrier f ₁ transmitted from the opposite station is normally demodulated, but the demodulation frequency of the demodulator 13 is set to f _{R as} soon as the reception end of the burst is detected. Switch to ′.

As a result, the signal 122 transmitted from the master station is demodulated, and thus the forced disconnection command R is decoded. If the content of R is directed to the own station, the transmission of the own station is immediately stopped. This is modulator 10
This is achieved by turning off the output of. Otherwise, the demodulator reception frequency is the signal block 1 from the master station.
Immediately after receiving one 22, the value is set to f ₁ again, and the individual communication path is maintained. Here, the setting of the frequency can be easily performed by a known frequency synthesizer included in the demodulator. The detection of the end of burst can be performed by the demodulator 13 itself by a known technique such as detection of received power or addition of a code indicating the end.

As is clear from the above description, the frequency f
_Since switching to R'is performed immediately after the end of the voice burst, if the voice burst interval T ₂ 126 becomes abnormally long, for example, it is left off-hook,
If the silent state continues for tens of minutes or hours, forced disconnection becomes impossible. To solve this, when T ₂ becomes equal to or longer than a constant time T ₁ 125 of, for example, several tens of seconds, the slave station modulator 10 pseudo-transmits a voice burst, and f _R is received at the slave station which receives the burst. It is used as a timing signal for switching to '. Since the content As124 of this pseudo voice burst is not a true voice, it is set as a unique identification code so as not to be output to the reception output 16.

It should be noted that the fact that the voice becomes voiced during the period in which the pseudo voice burst is transmitted and overlaps with the transmission timing of the original voice burst can be obtained by adding a delay larger than the length of the pseudo voice burst to the voice detecting section. Although it can be avoided, it is considered that the unique identification code in the pseudo voice burst is at most several tens of bits, so that the length of the pseudo voice burst can be made short enough not to be a problem.

As described above, in the above embodiment, an extra demodulator for always receiving the forced disconnection command in the slave station for the forced disconnection is unnecessary.

In the above embodiment, an example of sending a burst wave as the forced disconnection command signal sent from the master station R is shown, but this is continuous as in the fourth embodiment of the present invention shown in FIG. In the fourth embodiment, the transmission density of command signals is high, so that in addition to the effect of the above embodiment, there is also an effect that the interval between successive voice bursts can be shortened.

Next explained is the fifth embodiment of the invention. FIG. 7 is a diagram showing a communication control system of a satellite communication system according to a fifth embodiment of the present invention. In the figure,
Reference numeral 218 is encoded voice data to be communicated between the slave stations, and 219.
Is a preamble, 221 is a code (end code) indicating the end of voice data, 222 is a code (start code) indicating the start of voice data, and 220 is command data sent from the master station. FIG. 8 is a simple block diagram of a slave station when the communication system according to the fifth embodiment of the present invention is applied.

Next, the operation will be described. FIG. 7A shows the content of the modulated wave transmitted from the slave station at the carrier frequency f ₁ on the time axis.
The voice from the talker is transmitted to the portion as the encoded data. The coding rate is 32 Kbps when using ADPCM, for example. When the carrier wave is modulated at a speed slightly higher than this coding rate, for example, if it is modulated at a speed that is about 10% higher, it is possible to create a section in which the sound is sent for 500 msec and then the sound is not sent for 50 msec. Therefore, such a section can be defined as a pause section, and this section can be framed into the portions as indicated by 219, 221, and 222 in FIG. 7. Reference numeral 219 is a synchronization bit provided so that the slave station demodulator can quickly acquire synchronization, and is called a preamble. Reference numerals 221 and 222 are unique codes indicating the end and the beginning of the voice pause section.

FIG. 7 (b) shows a forced disconnection command signal transmitted from the master station at, for example, the carrier frequency f _R ′, and the command signal is stored in the portion indicated by 220 in FIG. Is transmitted as. The content of this data R is repeatedly transmitted as shown in the figure by the identification code of the slave station which is the target of forced disconnection.

FIG. 7 (c) shows the content of the carrier wave to be demodulated by the demodulator 13 of the slave station shown in FIG. 8. Normally, as shown in FIG. Although the individual communication carrier f ₁ is demodulated, the demodulation frequency of the demodulator 13 is switched to f _R ′ immediately after detecting the end code 221. As a result, the signal 2 transmitted from the master station
Are demodulated, and thus the forced disconnection command R is decoded. If the contents of R are directed to your station,
The transmission of its own station is immediately stopped. This is accomplished by turning off the output of modulator 10. Otherwise,
The reception frequency of the demodulator is set to f ₁ again immediately after receiving one signal block 220 from the master station, and the start code C
The individual communication path is maintained by detecting s222. Here, the setting of the frequency can be easily performed by a known frequency synthesizer included in the demodulator.

In the above embodiment, the carrier wave transmitted from the slave station and the master station is a continuous wave, but it may be a burst wave as in the sixth embodiment of the present invention shown in FIG. The same effect as that of the above embodiment is obtained.

[0045]

As described above, according to the satellite communication system of the present invention, the reception frequency is switched by utilizing the short time between the voice bursts, and the forced disconnection is intermittently transmitted by one demodulator. Since the method is such that the command demodulation and the voice demodulation can be performed, there is an effect that the device of the slave station can be inexpensive.

Further, according to the satellite communication system of the present invention, the reception frequency is switched by utilizing the short time between the voice bursts, and the demodulation and the voice of the forced disconnection command continuously transmitted by one demodulator are performed. Since it is a system capable of demodulating, the device of the slave station can be inexpensive.

Further, according to the satellite communication system of the present invention, the reception frequency is switched by utilizing the short time between the voice bursts and the demodulation and the voice of the forced disconnection command intermittently transmitted by one demodulator are performed. Since it is a system capable of demodulating, the device of the slave station can be inexpensive. Further, even if the interval between the voice bursts becomes long, the pseudo voice bursts are transmitted so that the timing for performing the forced disconnection can be found, so that there is an effect that the disconnection can be performed promptly.

Further, according to the satellite communication system of the present invention, the reception frequency is switched by utilizing the short time between the voice bursts and the demodulation and the voice of the forced disconnection command continuously transmitted by one demodulator. Since it is a system capable of demodulating, the device of the slave station can be inexpensive. Further, even if the interval between the voice bursts becomes long, the pseudo voice bursts are transmitted so that the timing for performing the forced disconnection can be found, so that there is an effect that the disconnection can be performed promptly.

Further, according to the satellite communication system of the present invention, the individual communication wave and the forced disconnection command wave that are continuously transmitted can be obtained by performing the framing so that the pause section is created at a higher rate than the voice coding. Can be received in a time-division manner, so that the demodulator of the slave station can be configured by one unit, so that the device can be inexpensive.

Further, according to the satellite communication system of the present invention, the individual communication wave and the forced disconnection command wave transmitted intermittently by framing so as to create a pause section at a higher rate than voice coding. Can be received in a time-division manner, so that the demodulator of the slave station can be configured by one unit, so that the device can be inexpensive.

[Brief description of drawings]

FIG. 1 is a diagram showing a communication control system of a satellite communication system according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a slave station to which the communication control system according to the first embodiment of the present invention is applied.

FIG. 3 is a diagram showing a communication control system of a satellite communication system according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a communication control system of a satellite communication system according to a third embodiment of the present invention.

FIG. 5 is a configuration diagram of a slave station to which a communication control system according to a third embodiment of the present invention is applied.

FIG. 6 is a diagram showing a communication control system of a satellite communication system according to a fourth example of the present invention.

FIG. 7 is a diagram showing a communication control system of a satellite communication system according to a fifth embodiment of the present invention.

FIG. 8 is a configuration diagram of a slave station to which a communication control system according to a fifth embodiment of the present invention is applied.

FIG. 9 is a diagram showing a communication control system of a satellite communication system according to a sixth embodiment of the present invention.

FIG. 10 is a block diagram of a conventional satellite communication system.

FIG. 11 is a configuration diagram of a slave station according to a conventional communication control method.

FIG. 12 is a diagram showing an arrangement example of carrier waves in a satellite communication system.

FIG. 13 is a diagram showing a connection and release procedure of the DAMA system.

FIG. 14 is a diagram showing a forced disconnection procedure of the DAMA system.

[Explanation of symbols]

 18 audio burst 19 preamble 20 audio data 21 forced disconnection command data 22 forced disconnection command signal 118 audio burst 119 preamble 120 audio data 121 forced disconnection command data 122 forced disconnection command signal 123 pseudo audio burst 124 pseudo audio identification data 218 audio data 219 preamble 220 Forced disconnection command data 221 Voice data end code 222 Voice data start code

Claims (6)

[Claims] 1. A request allocation connection method, which comprises a master station and a plurality of slave stations, and an individual communication path between the slave stations is set according to a request from the slave station having a connection request to the master station. In the satellite communication system operated by the voice activation method, the carrier for individual communication sent from the slave station set to is sent only while voice is present. Means for intermittently broadcasting a control signal for forcibly disconnecting the communication carrier wave with the use carrier wave, and the slave station performs the common control immediately after the end of the individual communication carrier wave received in burst by voice activation. By receiving the signal for a certain period of time, it is determined whether or not the local station communication channel should be disconnected, and if the control signal that it should be disconnected is received, the communication channel is released. Otherwise, satellite communication system, characterized in that to continue communication back to the state immediately receive conventional individual communication carriers. 2. A master station and a plurality of slave stations are used, and an individual communication path between the slave stations uses a request allocation connection method set in accordance with a request from the slave station having a connection request to the master station. In the satellite communication system operated by the voice activation method, the carrier for individual communication sent from the slave station set to is sent only while voice is present. Means for continuously broadcasting a control signal for forcibly disconnecting the communication carrier wave using the carrier wave for communication, and the slave station controls the common control immediately after the end of the carrier wave for individual communication received in burst by voice activation. By receiving the signal for a certain period of time, it is determined whether or not the local station communication channel should be disconnected, and if the control signal that it should be disconnected is received, the communication channel is released. Otherwise, satellite communication system, characterized in that to continue communication back to the state immediately receive conventional individual communication carriers. 3. A master station and a plurality of slave stations are used, and an individual communication path between the slave stations uses a request allocation connection method set in accordance with a request from the slave station having a connection request to the master station. In the satellite communication system operated by the voice activation method, the carrier for individual communication sent from the slave station set to is sent only while voice is present. The mobile station is provided with means for intermittently broadcasting a control signal for forcibly disconnecting the communication carrier wave, the slave station is provided with means for transmitting a pseudo voice burst when voice is not present for a certain period of time, and the slave station is The communication channel for the local station is switched off by receiving the common control signal for a certain time immediately after the end of the carrier wave for individual communication that is received in a burst by voice activation. It is determined whether or not to disconnect, and if the control signal to disconnect is received, the communication channel is released, and if not, the communication immediately returns to the state of receiving the carrier wave for individual communication. A satellite communication system characterized by continuing. 4. A master station and a plurality of slave stations are used, and an individual communication path between the slave stations uses a request allocation connection method which is set in response to a request from the slave station having a connection request to the master station. In the satellite communication system operated by the voice activation method, the carrier for individual communication sent from the slave station set to is sent only while voice is present. The mobile station is provided with means for continuously broadcasting a control signal for forcibly disconnecting the communication carrier wave, and the slave station is provided with means for sending out a pseudo voice burst when voice is not present for a certain time or longer, and the slave station is The communication channel for the local station is switched off by receiving the common control signal for a certain time immediately after the end of the carrier wave for individual communication that is received in a burst by voice activation. It is determined whether or not to disconnect, and if the control signal to disconnect is received, the communication channel is released, and if not, the communication immediately returns to the state of receiving the carrier wave for individual communication. A satellite communication system characterized by continuing. 5. A satellite communication using a request allocation connection method, which comprises a master station and a plurality of slave stations, and an individual communication path between the slave stations is set according to a request from the slave station having a connection request to the master station. In the system, the slave station performs framing means for performing framing so that a continuous individual communication carrier wave transmitted from the slave station has a pause interval at which voice and other signals necessary for communication between slave stations are not transmitted at regular intervals. The master station is provided with means for continuously broadcasting a command signal for forcibly disconnecting the communication carrier wave using a separately defined control common carrier wave for the system, and the slave station is transmitted from the slave station opposite to the communication. It identifies the pause section in the individual communication carrier wave, receives the control carrier wave from the master station during the pause section, determines whether to disconnect the local station communication path, and receives the control signal to disconnect. If Is a satellite communication system characterized by continuing the inter-slave station communication by releasing the communication path and returning to the state of receiving the original individual communication carrier again if not. 6. A satellite communication using a request allocation connection method, which comprises a master station and a plurality of slave stations, and an individual communication path between the slave stations is set according to a request from the slave station having a connection request to the master station. In the system, the framing means performs framing so that the slave station has a pause interval in which an intermittent individual communication carrier wave transmitted from the slave station does not transmit voice and other signals necessary for inter-slave station communication. The master station is provided with means for intermittently broadcasting a command signal for forcibly disconnecting the communication carrier wave using a separately defined control common carrier wave for the system, and the slave station is transmitted from the slave station opposite to the communication. It identifies the pause section in the individual communication carrier wave, receives the control carrier wave from the master station during the pause section, determines whether to disconnect the local station communication path, and receives the control signal to disconnect. If Is a satellite communication system characterized by continuing the inter-slave station communication by releasing the communication path and returning to the state of receiving the original individual communication carrier again if not.