High data rate satellite communication system

• US 5,625,624 A
• Filed: 10/21/1993
• Issued: 04/29/1997
• Est. Priority Date: 10/21/1993
• Status: Expired due to Term

• Current Assignee: Hughes Electronics Corporation (Rtx Corporation)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Rosen, Harold A., Ramanujam, Parthasarathy, Strodtbeck, Andrew L., Reinhardt, Victor S., Vollbrecht, Jennifer L., Busche, Gregory C.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): HOM, SHICK C
• Application Number:
  US08/142,524
• Time in Patent Office: 1,286 Days
• Field of Search: 370/49.5, 370/50, 370/18, 370/75, 370/97, 370/95.3, 455/12.1, 455/13.1, 455/13.3, 455/3.2, 379/105
• US Class Current: 370/307
• CPC Class Codes: H04B 7/18523 Satellite systems for providing broadcast service to terrestrial stations, i.e. broadcast satellite service arrangements specially adapted for satellite broadcast receiving H04H40/90; picture transmission via satellite H04N1/00103; television transmission via satellite H04N7/20

Abstract

A satellite-based communication system providing high rate transfer of data between linked terminals. The system comprises a plurality of user terminals (VSAT'"'"'s) that are linked by and that communicate with each other by way of a satellite-based relay system. A network control center provides configuration signals that control the satellite relay system and coordinate linking of terminals to each other. Frequency division multiplexing uplinks are used from the terminals and the network control center to the satellite relay system. Time division multiplexing are used on downlinks from the satellite relay system to the terminals and the network control center. Each user terminal comprises a data compression and decompression circuit, a transceiver, and an antenna for transmitting and receiving data to and from the satellite relay system. The satellite relay system comprises a satellite, a wide area antenna, a plurality of receive antennas, a plurality of transmit antennas, and a signal processor. The wide area antenna is provided for communicating control signals between the user terminals and the network control center. The plurality of receive antennas operate in a first frequency band and produce a first plurality of beams that cover a service area. The plurality of receive antennas receive time domain modulated data from the user terminals. The plurality of transmit antennas operate in a second frequency band and produce a second plurality of beams that cover the service area. The plurality of transmit antennas transmit frequency domain modulated data to the user terminals. The signal processor demodulates the time domain modulated data received from a user terminal, routes the demodulated data so that it is transmitted to a second user terminal, remodulates the data to provide frequency domain modulated data, and transmits the frequency domain modulated data to the second user terminal. Video cameras and monitors are coupled to the user terminals to provide for video teleconferencing.

Claims

1. A high data rate satellite communication system comprising:

a plurality of user terminals that each comprises;

a transceiver for receiving input data and outputting output data, for encoding the input data to provide frequency division multiplexed data, for decoding received encoded data comprising time division multiplexed data to produce the output data, and for generating terminal control signals that identify source and destination user terminals that are to communicate with each other; and

an antenna coupled to the transceiver for transmitting and receiving the multiplexed data and the terminal control signals;

a satellite relay system comprising;

a satellite;

a wide area antenna disposed on the satellite for communicating satellite configuration and control signals between a network control center and the satellite relay system, and for communicating the terminal control signals between the user terminals and the satellite relay system;

a plurality of receive antennas disposed on the satellite that operate in a first frequency band that comprises a first plurality of subbands, the receive antennas operating on different subbands and producing a first plurality of beams that cover a predefined area for receiving the frequency division multiplexed data from the user terminals;

a signal processor coupled to the plurality of receive antennas for demodulating the frequency division mulitiplexd data received from a source user terminal, for routing the demodulated data so that it is transmitted to a desired destination user terminal, for remodulating the demodulated data to provide remodulated time division multiplexed data, and for transmitting the remodulated time division multiplexed data to the desired destination user terminal;

a plurality of feed horns that couple the signal processor to the receive antennas, each receive antenna producing a seperate beam from each feed horn to which it is coupled, the feed horns being oriented towards their respective receive antennas such that each receive antenna produces beams that do not overlap with each other within the predefined area, the beams from the receive antennas facilitating geographic frequency reuse by creating an interlaced pattern of beams that covers the predefined area;

a plurality of transmit antennas disposed on the satellite and coupled to the signal processor that operate in a second frequency band that comprises a second plurality of subbands, the transmit antennas operating on different subbands and producing a second plurality of beams that cover the predefined area for transmitting the remodulated time division mulitiplexed data to the desired destination user terminal; and

a plurality of feed horns that couple the signal processor to the transmit antennas, each transmit antenna producing a seperate beam for each feed horn to which it is coupled, the feed horns being oriented towards their respective transmit antennas such that each transmit antenna produces beams that do not overlap with each other within the predefined area, the beams from the transmit antennas facilitating geographic frequency reuse by creating an interlaced pattern of beams that cover the predefined area;

and wherein the network control center comprises;

a control processor for processing the terminal control signals that link the source and destination user terminals by way of the satellite relay system, and for generating the satellite configuration and control signals that configure and control the satellite relay system and route encoded video and audio data between source and destination user terminals; and

an antenna coupled to the control processor for transmitting and receiving the satellite configuration and control signals and the terminal control signals.

2. The system of claim 1 wherein the plurality of user terminals each further comprise:

a data compression and decompression circuit for receiving video and audio input data and outputting video and audio output data;

a video camera coupled to the data compression and decompression circuit for providing the video and audio input data; and

a video monitor coupled to data compression and decompression circuit for displaying received video output data and outputting received audio data.

4. The satellite communication system of claim 1, comprising at least four transmit and four receive antennas.

5. The satellite communication system of claim 1, in which multiplexed data are generated in the digital domain with concatenated forward error control coding to mitigate system self interference.

6. The satellite communication system of claim 1, in which the first and second pluralities of beams each comprise polarized beams.

3. A high data rate satellite communication system comprising:

a plurality of user terminals that each comprises;

a data compression and decompression circuit for receiving video and audio input data and outputting video and audio input data;

a video camera coupled to the data compression and decompression circuit for providing the video and audio input data;

a video monitor coupled to the data compression and decompression circuit for displaying received video output data and outputting received audio data;

a transceiver coupled to the data compression and decompression circuit for encoding the video and audio input data to provide frequency division multiplexed data, and for decoding received encoded video and audio data comprising time division multiplexed data; and

a satellite relay system comprising;

a satellite;

a wide area antenna disposed on the satellite for communicating satellite configuration and control signals between a network control center and the satellite relay system, and for communicating the terminal control signals between the user terminals and the satellite relay system;

a plurality of receive antennas disposed on the satellite that operate in a first frequency band that comprises a first plurality of subbands, the receive antennas operating on different subbands and producing a first plurality of beams that cover a predefined area for receiving the frequency division multiplexed data from the user terminals;

a signal processor coupled to the plurality of receive antennas for demodulating the frequency division multiplexed data received from a source user terminal, for routing the demodulated data so that it is transmitted to a desired destination user terminal, for remodulating the demodulated data to provide remodulated time division multiplexed data, and for transmitting the remodulated time division multiplexed data to the desired destination user terminal;

a plurality of feed horns that couple the signal processor to the receive antennas, each receive antenna producing a seperate beam for each feed horn to which it is coupled, the feed horns being oriented towards their respective receive antennas such that each receive antenna produces beams that do not overlap with each other within the predefined area, the beams from the receive antennas facilitating geographic frequency reuse by creating an interlaced pattern of beams that cover the predefined area;

a plurality of transmit antennas disposed on the satellite and coupled to the signal processor that operate in a second frequency band that comprises a second plurality of subbands, the transmit antennas operating on different subbands and producing a second plurality of beams that cover the predefined area for transmitting the remodulated time division multiplexed data to the desired destination user terminal; and

a plurality of feed horns that couple the signal processor to the transmit antennas, each transmit antenna producing a separate beam for each feed horn to which it is coupled, the feed horns being oriented towards their respective transmit antennas such that each transmit antenna produces beams that do not overlap with each other within the predefined area, the beams from the transit antennas facilitating geographic frequency reuse by creating an interlaced pattern of beams that cover the predefined area;

and wherein the network control center comprises;

a control processor for processing the terminal control signals that link the source and destination user terminals by way of the satellite relay system, and for generating the satellite configuration and control signals that configure and control the satellite relay system and route encoded video and audio data between source and destination user terminals; and

an antenna coupled to the control processor for transmitting and receiving the satellite configuration and control signals and the terminal control signals.

7. The satellite communication system of claim 3, comprising at least four transmit and four receive antennas.

8. The satellite communication system of claim 3, in which multiplexed data are generated in the digital domain with concatenated forward error control coding to mitigate system self interference.

9. The satellite communication system of claim 3, in which the first and second pluralities of beams each comprise polarized beams.