JPH0523644U - DAMA communication device - Google Patents

Abstract

(57) [Abstract] [Purpose] A method that makes it impossible for a third party to intercept the DAMA communication method. [Structure] A scrambling pattern signal is added to the CSC signal from the master station in addition to the channel setting signal, and only the two talk stations set this pattern so that reception by other modulator / demodulators becomes impossible. [Effect] Interception by a third party becomes impossible.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a DAMA (Demand Assignment Multiple Access) communication system for performing line assignment in a satellite communication system, for example.

[0002]

[Prior Art]

 FIG. 2 is a conceptual diagram of a satellite communication system for performing a conventional DAMA communication system. In the figure, 1 is a communication satellite having a repeater (not shown), 2 is a master station for allocating satellite channels, 3a, 3b ... 3n are slave stations. Further, FIG. 3 is a diagram showing an example of an arrangement of the digital SCPC (Single Channel Per Carrier) lines of the repeaters in the communication satellite 1. In the figure, 4 and 5 are CSC lines, and 6a to 6n are assignment SCPC circuits. Is.

Next, the operation will be described. When a call request is generated at a certain slave station, the slave station uses the CSC to transmit call / call information (line request signal) to the master station 2. Upon receiving this outgoing / incoming call information, the master station 2 selects an empty SCPC1 peri-channel and sends a line designation signal to the slave station by the CSC. On the other hand, the line is set up by the slave station, that is, the called station and the calling station, receiving this line designation signal and setting each SCPC device to the designated SCPC channel. The trunk line modulator / demodulator that was set to the CSC frequency at that time is changed to the specified frequency.

[0004]

[Problems to be solved by the device]

 Since the conventional DAMA communication system is configured as described above, the main purpose of the master station is to allocate the line, and when a third party allocates and sets the frequency, the call is intercepted. I will end up.

The present invention was made in order to solve the above problems, and an object thereof is to obtain a DAMA communication system which also has secret communication characteristics in the master station.

[0006]

[Means for Solving the Problems]

 In the DAMA communication system according to the present invention, the SCPC modulator / demodulator of each slave station can set the secret line scramble at the same time as setting the assigned line so that only the allocated parties can talk.

[0007]

[Action]

 In the DAMA communication system according to the present invention, a different scramble pattern (secret story) is set each time the line is set, so that interception by a third party becomes impossible.

[0008]

【Example】

 Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an operation sequence of a DAMA communication system according to an embodiment of the present invention. In FIG. 1, 101 is each slave station (in the figure, the calling station is the slave station 3a and the called station is the slave station 3b. Is a line request signal transmitted from the master station 2 to the master station 2, and 102 is a channel designation signal transmitted from the master station 2 to the slave stations 3a and 3b.

FIG. 4 is a block diagram showing the structure of a slave station according to the present invention. In the figure, 7 is a modulator / demodulator, 8 is a DAMA controller for controlling the DAMA system, and 9 is a transmitter / receiver including an antenna. , 10 is a switch, and 11 is a scrambler and descrambler device built into the modulator / demodulator 7.

Next, the operation will be described. When a request for an incoming / outgoing call from the subscriber of the slave station 3a to the slave station 3b is generated, the exchange 10 outputs a dial number or the like to the trunk line modulator / receiver 7, and the DAMA control unit 8 analyzes this number and the local station Send the partner station number on the CSC line. (Line request signal 101). On the other hand, the frequency of the trunk line modulator / demodulator 7 is set by the line designating signal 102 from the master station 2. At the same time, the designating signal of 102 contains scrambled and descrambled pattern signals. Set to scramble or descramble. This information is similarly transmitted to 3b by the designated signal of 102, and the scrambling / descramble pattern is set in the station of 3b. However, the patterns of stations 3a and 3b are assigned so that they match in transmission and reception.

Example 2. Further, in the above embodiment, the scramble pattern is transmitted when the master station's line is designated, but in order to make it more difficult to intercept, the master station transmits several types of scramble patterns to the slave station to designate the line. After the line is set, the slave station may perform pattern setting again at regular time intervals as shown in FIG. 5 for communication. By doing so, even if a third party attempts to intercept, the scrambling pattern is changed sequentially, making it impossible to receive.

[0012]

[Effect of the device]

 As described above, according to the present invention, since the scramble pattern of each assigned SCPC line is different, only the assigned slave station can be used, and there is the effect that interception by a third party becomes impossible. can get.

[Brief description of drawings]

FIG. 1 is an embodiment of a DAMA communication system according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of satellite communication using the DAMA communication method.

FIG. 3 is an example of an arrangement of SCPC in a communication satellite.

FIG. 4 is a block diagram showing a configuration of a slave station according to the present invention.

5 is an explanatory diagram of FIG. 4. FIG.

[Explanation of symbols]

 1 communication satellite 2 parent station 3a to 3n slave station 4 CSC line (parent to child) 5 CSC line (child to parent) 6a to 6n SCPC line 7 relay line modulator / demodulator 8 DAMA controller 9 transceiver 10 switch 11 scramble, de Scrambler

Claims (1)

[Scope of utility model registration request] 1. A CSC (common signal control channel) for arranging a large number of 1-carrier SCPC lines per communication path in a repeater of a communication satellite and controlling call connection between each slave station.
In the DAMA communication system in which the CSC is used to centrally manage the call connection control in the master station when connecting between arbitrary slave stations, the master station connects the call scrambling mode on the CSC signal. A DAMA communication device characterized by being contacted at the time of control.