TDMA beacon for satellite system synchronization

• US 6,684,070 B1
• Filed: 09/26/2000
• Issued: 01/27/2004
• Est. Priority Date: 09/26/2000
• Status: Expired due to Term

• Current Assignee: Hughes Electronics Corporation (AT&T, Inc.)
• Original Assignee: Hughes Electronics Corporation (AT&T, Inc.)
• Inventors: Berman, Arnold L., Chie, Chak M., Rosen, Harold A.
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): Corsaro, Nick
• Application Number:
  US09/670,987
• Time in Patent Office: 1,218 Days
• Field of Search: 455/3.02, 455/3.01, 455/13.2, 455/12.1, 455/427, 455/428, 455/429, 455/430, 455/502, 455/503, 370/324, 370/514, 370/515, 370/316, 370/319, 370/321, 370/347
• US Class Current: 455/427
• CPC Class Codes: H04B 7/2125 Synchronisation

Abstract

A TDMA beacon for satellite system synchronization includes a beacon signal generator and a time division multiplexed switch. The beacon signal generator generates a beacon signal. The TDM switch is coupled to the beacon signal generator and receives the beacon signal. The TDM switch embeds the beacon signal with a data signal into a TDMA signal. The TDMA signal is then broadcast to a ground station where the beacon signal may be extracted from the TDMA signal and used to synchronize a terminal with the satellite system.

Claims

1. A TDMA beacon for satellite system synchronization comprising:

a beacon signal generator capable of generating a beacon signal, said beacon signal generator is a pseudorandom number generator reset to a preset state using a reset signal;

a TDM switch coupled to said beacon signal generator and receiving said beacon signal, said TDM switch multiplexing a data signal into N downlink frame slots based on a timing signal to generate a TDMA signal, wherein one of said N downlink frame slots comprises said beacon signal;

a modulator coupled to said TDM switch and receiving said TDMA signal, said modulator modulating said TDMA signal;

a demodulator remote from said modulator, said demodulator demodulating said TDMA signal;

a beacon receiver coupled to said demodulator and receiving said TDMA signal, said beacon receiver extracting said beacon signal from said one of said N downlink frame slots for timing synchronization; and

data recovery electronics coupled to said demodulator and receiving said TDMA signal, said data recovery electronics synchronized with said TDM switch based upon said beacon signal, said data recovery electroics generating said data signal.

2. The TDMA beacon for satellite system synchronization as recited in claim 1, wherein said beacon signal is a pseudorandom number sequence.

3. The TDMA beacon (18) for satellite (12) system synchronization as recited in claim 1, wherein said beacon signal and said data signals are generated at baseband.

4. The TDMA beacon (18) for satellite (12) system synchronization as recited in claim 1, wherein said beacon signal defines said downlink frame structure.

5. The TDMA beacon (18) for satellite (12) system synchronization as recited in claim 1, wherein said beacon signal and said data signal share a same radio frequency and interference frequency path.

6. A processing satellite communication system comprising:

a ground station;

a satellite in orbit and in communication with said ground station, said satellite having a TDMA beacon for satellite system synchronization comprising;

a beacon signal generator located in said satellite capable of generating a beacon signal, said beacon signal generator is a pseudorandom number generator Mat is reset to a preset state using a reset signal;

a TDM switch located in said satellite and coupled to said beacon signal generator and receiving said beacon signal, said TDM switch multiplexing a data signal into N downlink frame slots based on a timing signal to generate a TDMA signal, wherein one of said N downlink frame slots comprises said beacon signal;

a modulator located in said satellite and coupled to said TDM switch and receiving said TDMA signal, said modulator modulating said TDMA signal;

a demodulator located in said ground station said demodulator demodulating said TDMA signal;

a beacon receiver located in said ground station and coupled to said demodulator and receiving said TDMA signal, said beacon receiver extracting said beacon signal from said one of said N downlink frame slots for timing synchronization; and

data recovery electronics located in said ground station and coupled to said demodulator and receiving said TDMA signal, said data recovery electronics synchronized with said TDM switch based upon said beacon sign recovery electonics generating said data signal.

7. The processing satellite communication system as recited in claim 6, wherein said beacon signal is a pseudorandom number sequence.

8. The processing satellite communication system as recited in claim 6, wherein said beacon signal and said data signals are generated at baseband.

9. The processing satellite communication system as recited in claim 6, wherein said beacon signal defines said downlink frame structure.

10. The processing satellite communication system as recited in claim 6, wherein said beacon signal and said data signal share a same radio frequency path.

11. A method for satellite system synchronization comprising the steps of:

generating a data signal;

generating a beacon signal using a pseudorandom number generator that is reset to a preset state using a reset signal;

generating a timing signal;

multiplexing said data signal to generate a downlink frame having N downlink frame slots, wherein one of said N downlink frame slots comprises said beacon signal to generate a TDMA signal;

modulating said TDMA signal to generate a downlink frame having N downlink frame slots, wherein one of said N downlink frame slots comprises said beacon signal to generate a TDMA signal;

modulating said TDMA signal to generate a modulated TDMA signal;

broadcasting said modulated TDMA signal;

receiving said modulated TDMA signal;

demodulating said modulated TDMA signal to generate said TDMA signal;

extracting said beacon signal from said TDMA signal;

synchronizing a ground station terminal using said beacon signal; and

extracting said data signal from said TDMA signal based upon said beacon signal.