Cellular/satellite communications systems with improved frequency re-use

• US 5,812,947 A
• Filed: 12/02/1996
• Issued: 09/22/1998
• Est. Priority Date: 01/11/1994
• Status: Expired due to Term

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Dent, Paul W.
• Primary Examiner(s): VO, NGUYEN THANH
• Application Number:
  US08/757,635
• Time in Patent Office: 659 Days
• Field of Search: 455/7, 455/11.1, 455/12.1, 455/13.4, 455/17, 455/23, 455/33.1, 455/54.1, 455/56.1, 455/63, 455/67.1, 455/67.3, 455/69, 455/102-103, 455/226.1, 455/226.2 , 455/422, 455/517, 455/524, 455/427
• US Class Current: 455/427
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 1/288 Satellite antennas
• CPC Class Codes: H01Q 21/08 the units being spaced along or adjacent to a rectilinear path waveguide fed H01Q21/0037
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 25/00 Antennas or antenna systems providing at least two radiating patterns arrangements for changing or varying the orientation or the shape of the directional pattern H01Q3/00
• CPC Class Codes: H01Q 25/007 using two or more primary active elements in the focal region of a focusing device for operation on different wavebands H01Q5/22
• CPC Class Codes: H04B 7/0837 using pre-detection combining H04B7/0868 takes precedence
• CPC Class Codes: H04B 7/0851 using training sequences or error signal minimizing error signal H04B7/0854
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04B 7/18515 Transmission equipment in satellites or space-based relays
• CPC Class Codes: H04B 7/18532 Arrangements for managing transmission, i.e. for transporting data or a signalling message
• CPC Class Codes: H04B 7/18567 Arrangements for providing additional services to the basic mobile satellite telephony service
• CPC Class Codes: H04B 7/2041 Spot beam multiple access
• CPC Class Codes: H04B 7/2046 SS-TDMA, TDMA satellite switching
• CPC Class Codes: H04L 1/007 Unequal error protection for format H04L1/0078; for codes per se H03M13/35
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/021 Estimation of channel covariance
• CPC Class Codes: H04L 25/03203 Trellis search techniques
• CPC Class Codes: H04L 25/0328 with interference cancellation circuitry adaptations for interference cancellation within a sequence estimator H04L25/03305; interference related aspects of direct sequence spread spectrum H04B1/7097; interference related aspects of frequency hopping spread spectrum H04B1/715; see also H04B1/10
• CPC Class Codes: H04L 25/03299 : with noise-whitening circuitry
• CPC Class Codes: H04L 25/03331 : Arrangements for the joint estimation of multiple sequences
• CPC Class Codes: H04W 16/02 : Resource partitioning among network components, e.g. reuse partitioning
• CPC Class Codes: H04W 16/14 : Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 74/08 : Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 84/025 : with acknowledge back capability
• CPC Class Codes: H04W 84/042 : Public Land Mobile systems, e.g. cellular systems
• CPC Class Codes: H04W 84/06 : Airborne or Satellite Networks space-based or airborne stations H04B7/185

Abstract

A radio communication system and method for minimizing co-channel interference comprises a technique for communicating between first stations and second stations. The technique involves: i) processing, at a first station, first signals into a form representative of modulated radio signals; ii) combining the representations to form a number of transmit signals using a set of combining parameters; iii) transmitting the transmit signals using a transmitter and antenna for each of the signals; iv) receiving the transmit signals at the second stations to produce received signals; v) measuring at the second stations an amount received of at least one unwanted signal relative to the amount of wanted signal received to produce measurement results; vi) transmitting the measurement results from the second stations to the first station; and vii) receiving the measurement results at the first station and using the results to modify the combining parameters such that unwanted signals received at the second stations are reduced and wanted signals enhanced. The measuring step includes the step of correlating received signals with known signals to produce the amount of at least one unwanted signal, and the amount of wanted signal.

Claims

1. A method for communicating a plurality of first signals from a first station to a corresponding plurality of second stations and a plurality of second signals from said second stations to said first station involving the steps of:

processing said first signals into a form representative of modulated radio signals;

combining said representations to form a number of transmit signals using a set of combining parameters;

transmitting said transmit signals using a transmitter and antenna for each of said signals;

receiving said transmit signals at said second stations to produce received signals;

measuring at said second stations an amount received of at least one unwanted signal relative to the amount of wanted signal received to produce measurement results;

transmitting said measurement results from said second stations to said first station;

receiving said measurement results at said first station and using said results to modify said combining parameters such that unwanted signals received at said second stations are reduced and wanted signals enhanced;

wherein said step of measuring further includes the step of correlating said received signals with known signals to produce said amount of at least one unwanted signal, and said amount of wanted signal.

2. A method according to claim 1 in which said first station comprises a ground station communicating with at least one orbiting satellite.

3. A method according to claim 2 in which said corresponding transmitters form part of a satellite transponder for relaying said transmit signals from said ground station via said satellite.

4. A method according to claim 3 in which said transmit signals are relayed by a coherent transponder in such a way as to preserve their relative phases and amplitudes.

5. A method according to claim 1, wherein said measuring step includes forming a ratio of said amount of at least one unwanted signal to said amount of wanted signal.

6. A method according to claim 5, wherein said ratio forms a complex value.

7. A method according to claim 1 in which said step of correlating said received signals with known signals comprises correlating said received signals with a set of codes.

8. A method according to claim 7, wherein said amount of wanted signal is produced by correlating said received signals with at least a first code, and said amount of at least one unwanted signal is produced by correlating said received signals with at least a second code.

9. A method according to claim 1, wherein said step of transmitting comprises transmitting only largest ones of said measurement results to said first station.

10. A method according to claim 1, wherein said step of receiving at the first station modifies said combining parameters such that wanted signals received at said second stations are maximized.

11. A method for communicating a plurality of first signals from a first station to a corresponding plurality of second stations and a plurality of second signals from said second stations to said first station involving the steps of:

processing said first signals into a form representative of modulated radio signals;

combining said representations to form a number of transmit signals using a set of combining parameters;

amplifying said transmit signals to desired transmit power levels and transmitting said transmit signals using a corresponding transmitter and antenna for each transmit signal;

measuring at said second stations an amount received of at least one unwanted signal relative to the amount of wanted signal received to produce measurement results;

transmitting said measurement results from said second stations to said first station;

receiving said measurement results at said first station and using said results to modify said combining parameters such that unwanted signals received at said second stations are reduced and the sum of said transmit power levels needed to transmit said first signals is reduced.

12. A method according to claim 11 in which said first station comprises a ground station communicating with at least one orbiting satellite.

13. A method according to claim 12 in which said corresponding transmitters form part of a satellite transponder for relaying said transmit signals from said ground station via said satellite.

14. A method according to claim 13 in which said transmit signals are relayed by a coherent transponder in such a way as to preserve their relative phases and amplitudes.

15. A method of claim 11, wherein said step of receiving said measurement results further reduces said sum of said transmit power levels to a minimum.

16. A system for wireless communication between at least one first station and at least one second station, comprising:

a first station including a processor for processing first signals into a form representative of modulated radio signals;

a first station combiner for combining said representations to form a number of transmit signals using a set of combining parameters;

a first station transmitter for transmitting said transmit signals;

a second station receiver for receiving said transmitted signals to produce received signals;

second station logic for determining an amount received by said receiver of at least one unwanted signal relative to the amount of wanted signal received by said receiver to produce measurement results;

a second station transmitter for transmitting said measurement results from said second station to said first station;

a first station receiver for receiving said measurement results from said second station transmitter;

wherein said first station uses said results to modify said combining parameters such that unwanted signals received at said second stations are reduced and wanted signals enhanced;

wherein said logic for determining further includes logic for correlating said received signals with known signals to produce said amount of at least one unwanted signal, and said amount of wanted signal.

17. A system according to claim 16, wherein said logic for determining includes forming a ratio of said amount of at least one unwanted signal to said amount of wanted signal.

18. A system according to claim 17, wherein said ratio forms a complex value.

19. A system according to claim 16 in which said logic for correlating said received signals with known signals comprises logic for correlating said received signals with a set of codes.

20. A system according to claim 19, wherein said amount of wanted signal is produced by correlating said received signals with at least a first code, and said amount of at least one unwanted signal is produced by correlating said received signals with at least a second code.

21. A system according to claim 16, wherein said second station transmitter transmits only largest ones of said measurement results to said first station.

22. A system according to claim 16, wherein said first station modifies said combining parameters such that wanted signals received at said second station are maximized.