JPS60167533A - Hybrid satellite communication system - Google Patents

Abstract

PURPOSE:To attain the high using efficiency of such a satellite circuit that is suited to transmission of the large capacity data and not economical with transmission of the small capacity data, by using a satellite circuit for a link having a large quantity of data to be transmitted and a ground circuit for a link having a small quantity of data respectively. CONSTITUTION:An earth station B contains a receiver 1 for broadcast satellite and a captain converter 2. When an access is given to a captain center 4 of a center station from the station B, a telephone set 3 is connected to a telephone receiver 15 of the center 4 via a ground circuit. When a terminal number is transmitted from the telephone 3, the center 4 delivers the data of a picture data memory 17 to every home via a broadcast satellite 5. In this case, the address data is added to the picture data and the terminal number of the station B is set to an address part. The number of own station is previously supplied to an address memory 11 for a converter 2 of the station B. An address comparison/data selection circuit 10 compares the data of the converter 2 with the received address data. Then the picture data is stored to a picture data memory 12 and displayed to a receiver 8 only when the coincidence is obtained from said comparison.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a satellite communication system, and particularly to a hybrid satellite communication system suitable for economical use of satellite communication lines.

[Backbone of invention]

Conventional satellite communication systems may use a satellite line for two-way communication, such as a single communication satellite, or use a satellite line only for one-way communication, such as a broadcasting satellite. However, two-way satellite links are used in systems such as the Captain System and VB2 (Video Response System), in which the center station and each terminal station individually transmit and receive data, and the amount of data transmitted in one-way links is large. When used in a system where the amount of data transmitted on links in the opposite direction is very small, the earth station equipment and satellite repeaters used for links with small amount of data transmission have drawbacks such as high cost per data amount. Ta.

Furthermore, if only one-way satellite lines were used in the above system, there was a drawback that control signals could not be sent from the terminal stations to the center station.

On the other hand, if a terrestrial line is used instead of a satellite line for data communication in the above system, the transmission cost will be extremely high if a new high-speed data transmission network is installed, and if a telephone network is used, Because high-speed data transmission is not possible, the Captain System, for example, has had drawbacks such as poor service to users, as it takes about 7 seconds to transmit one screen of image data.

[Purpose of the invention]

The purpose of the present invention is to eliminate the drawbacks of the conventional methods described above, and to provide a system that can economically utilize satellite communication lines in systems where the amount of data transmitted in one direction is large and the amount of data transmitted in the opposite direction is very small.・Providing an hybrid satellite communication system.

[Summary of the invention]

The present invention uses satellite lines for links with a large amount of data transmission, and uses terrestrial lines such as telephone lines for links with a very small amount of data transmission, making it suitable for small-capacity data transmission. A hybrid satellite communication system that makes it possible to efficiently use a satellite line that is not economical for other systems [Embodiments of the Invention] Embodiments of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a block diagram showing an embodiment of a hybrid satellite communication system according to the present invention. This embodiment uses a telephone line as the ground line and one channel of the broadcasting satellite channel as the satellite line in a satellite communication system that uses satellite channels by time division multiple access and demand assignment method. This is an example in which image data from the captain system is transmitted and the image is displayed on a receiver of a receiving device installed in each home.

Further, FIG. 2 is a diagram of an example of the image data frame of FIG. 1.

In Figure 1, % 1 is a normal broadcasting satellite receiver installed in each home, 2 is a captain converter added to it, and the broadcasting satellite receiver 1 and captain converter 2 connect the satellite line earth station of station B. When the channel of this broadcast satellite receiver 1 is set to the captain service channel, the image data from the captain center is processed via the captain converter 2, and the broadcast satellite receiver 1 is configured as a satellite line receiver. It has the function of displaying the image on the image receiver. 3 is the location and line of station B (
(telephone line) push-button telephone serving as a terminal, 4 a captain center serving as the A station (center station), 5 a broadcasting satellite, 6 a receiving antenna, 7 a receiver, 8 a picture receiver, a 9-digit demodulator, 1
0 is an address comparison/data selection circuit, 11 is an address memory, 12 is an image data memory, 15 is a pushbutton switch for address input, 14 is an image regeneration circuit, 15 is a pushbutton telephone receiver, and 16 is a control center. a processing device, 17 an image data memory, 18 a modulator, 19 a transmitter, 20
is the transmitting antenna.

With this configuration, when a user first makes a call to the captain center 4 using the push-button telephone 3 of the land line terminal of the B station when accessing the captain center 4 of the A station (center station) from the B station, the telephone 6 is connected to the push-button telephone receiver 15 of the captain center 4, and a connection tone is sent from the receiver 15. Next, when the telephone 3 sends the long-distance telephone number of the terminal number using the push button, the information about the captain center 4 is received by the central processing unit 16 via the push button telephone receiver 15, and then sent to the central processing unit 1.
6 reads out the image data stored in the image data memory 17 (first, data indicating the captain service menu), and transmits the image data to the modulator 18 and the transmitter 1.
9 and a transmitting antenna 20, and then is transmitted to all homes via a broadcasting satellite 5. At this time, address data is added to the image data as exemplified in FIG. 2, and the long-distance telephone number information of station B corresponding to the user is stored in this address part. Then, in the captain converter 2 of the satellite line earth station of the B station in each user's home, the long-distance telephone number of the own telephone 5 has been input into the address memory 1 from the address input push button switch 13, and this input After passing through the receiving antenna 6 and receiver 7 of the data and broadcasting satellite receiver 1.

The address data of the image data received via the demodulator 9 is compared in the address comparison/data selection circuit 10, and only if they match, the image data is transferred to the image data memory 2.
is stored in Further, the image data stored in the image data memory 2 is stored in the image data memory 12 until the primary image data is received, and is read out every 1/3o second to regenerate the image. It is converted into an image signal for a television receiver by the circuit 14 and then sent to the receiver 8.
and displayed on the screen. Thereafter, when the user sends an image selection signal from the pushbutton telephone 3 to the captain center 4 by pressing a button, new image data is broadcast under the control of the central processing unit 16 of the captain center 4 in the same manner as described above. The signal is sent via the satellite 5 to the user's broadcasting satellite receiver 1 and displayed on the image receiver 8.

The number of subscribers that can be used in the method of the above embodiment is, for example, 10 Mb at a data transmission rate of one channel of a broadcasting satellite channel.
ps, its usage efficiency is 50%, the traffic per each user terminal is 0.05ErJ-, and each screen is 20Kb.
If the screen is updated once every 5 seconds, the image data of ITS will be up to 25,000.

In addition, the time required to send images from the captain center 4 to each user's receiver 8 is approximately 0.5 seconds, excluding processing time at the captain center 4, which is significantly longer than the average of approximately 7 seconds in the conventional method. can be shortened.

FIG. 6 is a block diagram showing another embodiment of the hybrid satellite communication system based on the undiscovered invention. This embodiment is different from the embodiment shown in FIG. 1 in which the user of the captain service is required to send the non-priority phone number to the captain center 4 and input (register) it into the own captain center computer 2. On the other hand, this is an example in which these operations are not necessary.

In FIG. 3, the same reference numerals as in FIG. 1 indicate the same or corresponding parts, and 21 is an MP signal receiver, 22, 23 is a hybrid circuit, and 24 is an MP signal transmitter.

With this configuration, when a user first calls the captain center 4 of the A station using the push button telephone 3 of the B station, the telephone 6 is connected to the push button telephone receiver 15 of the captain center 4, and the telephone 6 is connected to the push button telephone receiver 15 of the captain center 4. A pre-connection message is sent from the receiver 15. Then, under the control of the central processing unit 16, the captain center 4 transmits the user's access number from the MP signal transmitter 24 to the M of the user's captain's converter 2 via the hybrid circuit 23, 22k using an MF (multi-frequency) signal.
The F signal is sent to the F signal receiver 21, which receives it and stores it in the address memory 11. At the same time, the captain center 4 reads the image data stored in the image data memory 17 (first, data indicating the captain service menu) under the control of the central processing unit 16, and transfers the image data to the modulator 18, the transmitter 19, and the transmitting antenna. 20
After that, it is transmitted to all homes via the broadcasting satellite 5.

At this time, the same access number as that previously sent to the user's captain converter 2 is used as the address data of the image data. The subsequent operations are similar to those shown in FIG.

In addition, in this embodiment, the user's captain converter 2
The access number, which is a serial number for accessing the Captain Center 4 by all users, is used as the address information for importing the image data sent to the user. It is also possible to use a telephone number.

In the method of the embodiment described above, it is not necessary to send the user's non-priority phone number to the captain center 4 and register it in the own captain center converter as shown in FIG.

The embodiments shown in FIGS. 1 and 3 above are examples in which the channels of one satellite are used by time division multiple access and demand assignment method.
It can also be applied when using frequency division multiple access, such as the demand assignment method of John Carrier, or when using spread spectrum multiple access using pseudo-random codes.

In such a case, means for controlling the satellite line so that only the data corresponding to the long-distance telephone number or access number of the terminal number can be imported from the captain center 4 of the A station to the B station of the user, And as a means of importing, as in the case of the above embodiment, the above number information is used in the address part of the data from the A station to the satellite line ground station of the B station, and the B station imports only the data that matches the number information. In addition, there is a method in which the frequency used by the satellite line at station A is transmitted as a frequency corresponding to the terminal number or access number of station B, and station B receives data on a frequency corresponding to its own number, or at station A. The data transmission signal of the satellite line of B
A method can be used in which the data is modulated and transmitted using a pseudorandom code corresponding to the terminal number or access number of the station, and the B station demodulates the data using a pseudorandom code corresponding to its own number and receives the data.

Further, although the above embodiment is a case of a captain system, the present invention is not limited to this, and the north line is not limited to a telephone line either.

According to the embodiments described above, data transmission via satellite lines such as the Captain System and V'fLS can be made very economical by using broadcasting satellite receivers that can be used in every home and telephones that are already in widespread use. can be implemented.

〔Effect of the invention〕

As explained above, the hybrid satellite communication system of the present invention has the features of being able to economically transmit large amounts of data over satellite lines, and the ability to economically transmit small amounts of data between land and lines, especially telephone lines. The combination of features makes it possible to economically utilize satellite communication lines in systems where the amount of data transmitted in one direction is large and the amount of data transmitted in the opposite direction is very small.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the hybrid satellite communication system according to the present invention, FIG. 2 is a diagram of an example of the image data frame of FIG. 1, and FIG. 3 is another embodiment of the hybrid satellite communication system according to the present invention. FIG. 2 is a block diagram illustrating an example. 1... Receiving device for broadcasting satellite of station B, 2...
... Captain's converter, 3... Valve open button telephone, 4... Captain center of station A, 5...
・Broadcasting satellite, 6...Receiving antenna, 7...Receiver, 5 11...Address memory, 12...Image data memory, 16... ...Push button switch for address input. 14... Image regeneration circuit, 15... Receiver for push button telephone, 16...
... Control central processing unit, 17 ... Image data system, 18 ... Modulator, 19 ... Transmitter, 20 ... Transmission antenna , 21...MP signal receiver, 22.25...Hybrid circuit. 24...MP signal transmitter. 6

Claims (1)

[Claims] 1. In a satellite communication system in which data is transmitted and received between A station and B station via a satellite, a satellite line is used to transmit data from A station to B station, and from B station to A station. A hybrid satellite communication system that uses terrestrial lines to transmit data. 2. The above-mentioned A station is a center station, the above-mentioned B station is a plurality of satellite line earth stations, and data transmission from A station to B station is performed by multiple access via satellites. The hybrid satellite communication method described in item 1. 3. Data is sent and received between stations A and B via satellite, and the satellite line is used to send data from station A to station B, and the terrestrial line is used to send data from station B to station A. In the hybrid satellite communication system, 1. A station has means for receiving terminal number data sent from the ground line terminal of B station, and address information of data for transmitting the terminal number data to B station via the satellite line. The terrestrial line terminal of the B station has means for transmitting its own terminal number to the A station, and the satellite line earth station of the B station has means for inputting its own terminal number, It has an address comparison/data selection means that compares the input terminal number and the address information of the data sent via the satellite line and takes in the data only when they match, and accesses from station B to station A. When the terminal number is sent from the terrestrial line terminal of B station to A station, data with the terminal number of B station set in the address part is sent from A station to B station via the satellite line, and from this, B station A hybrid satellite communication system characterized in that the satellite line earth station of the station takes in the data only when the address part of the data matches the terminal number input in advance. 4. The hybrid satellite communication system according to claim 3, wherein the terminal number of the own station in L is the terminal number designated by the own station. 5. 7. The hybrid satellite communication system according to claim 6, wherein the terminal number of the own station is a terminal number designated by the B station sent from the A station via the terrestrial line. & The hybrid satellite communication system according to claim 4 or 5, wherein the terminal number is not unique to station B but is an arbitrarily designated access number. Z. The hybrid satellite system according to claim 5, wherein the terminal number is sent from the A station to the B station side using the MP transmission system. 8. When transmitting data via the satellite line from station A to station B, the data is loaded with address information that means the terminal number specified by station B, and is imported into station B, so that the terminal number at station B is 7. The hybrid satellite communication system according to claim 6, wherein the address information is compared with the address information. 2. The hybrid satellite communication system according to claim 6, wherein the data transmission from the A station to the B station via the satellite line is modulated using a pseudo-random code modulation method.