Beamformer for multi-beam broadcast antenna

• US 6,788,250 B2
• Filed: 11/08/2002
• Issued: 09/07/2004
• Est. Priority Date: 11/09/2001
• Status: Expired due to Term

• Current Assignee: EMS Technologies, Inc. (Honeywell International Inc.)
• Original Assignee: EMS Technologies, Inc. (Honeywell International Inc.)
• Inventors: Howell, James M.
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US10/290,985
• Publication Number:
  US 20030090418A1
• Time in Patent Office: 669 Days
• Field of Search: 342/371, 342/372, 342/373, 342/377, 455/562.1
• US Class Current: 342/372
• CPC Class Codes: H01Q 21/061 Two dimensional planar arrays
• 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 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity

Abstract

A phased array antenna system operative to broadcast multiple beams that each include coded data for specific users located within the coverage area of the corresponding beam. An appropriate receiver then receives and decodes a particular beam to extract the specific data for a corresponding user. Multiple users may be assigned to each beam using frequency division or orthogonal code multiplexing, and the user data may be encoded into the beams using frequency shift key or phase shift key encoding. For each coding technique, the encoded antenna control signals are combined into a total gain and total phase shift control signal, which drives a single phase and gain control device for each antenna element. In addition, a single data modulator generates the coding parameters for the entire communication system.

Claims

1. A method for operating a phased array antenna system having a plurality of antenna elements, comprising the steps of:

receiving data for a plurality of users;

assigning the data to a plurality of beams;

defining a control signal for each antenna element in which each control signal comprises an associated beam component corresponding to each beam, and computing a total gain and a total phase shift for each antenna element comprising the vector sum of the beam components associated with the corresponding antenna element;

encoding each beam with the data assigned to that beam by generating the control signals to drive the antenna elements to generate the beams, wherein the combination of the control signals generated for all of the antenna elements causes the antenna to emit the plurality beams in which each beam carries encoded data for its assigned users; and

broadcasting the beams to deliver the data to the users.

2. The method of claim 1, wherein the step of assigning the data to the plurality of beams comprises:

determining a location associated with each user;

identifying a coverage area associated with each beam; and

assigning the user data to the beams so that the location of each user corresponds to the coverage area of the associated beam.

3. The method of claim 1, further comprising the steps of:

each user receiving an associated beam; and

each user decoding the received beam to recover that users associated data.

4. The method of claim a further comprising the steps of:

selecting an alternate set of desired beams; and

repeating the steps of claim 1 in connection with the alternate set of desired beams.

5. The method of claim 3, further comprising the steps of:

selecting an alternate code set; and

repeating the steps of claim 1 in connection with the alternate code set.

6. The method of claim 3, further comprising the steps of:

electing an alternate antenna; and

repeating the steps of claim 1 in connection with the alternate antenna.

7. The method of claim 1, wherein the step of encoding each beam with the data for the corresponding users further comprises the step of computing a vector sum of data signals for users assigned to the corresponding beam, wherein each data signal comprises a coding parameter representing data for a corresponding user.

8. The method of claim 7, wherein the step of encoding each beam with the data for the corresponding users further comprises the steps of:

computing an in-phase component for the control signal for each antenna element comprising a vector projection sum of in-phase beam components for the corresponding antenna element;

computing a quadrature component for the control signal for each antenna element comprising a vector projection sum of quadrature beam components for the corresponding antenna element; and

computing a total gain and a total phase shift for each antenna element from the corresponding in-phase and quadrature components.

9. The method of claim 8, wherein:

the in-phase beam components for each antenna element include an in-phase component corresponding to each beam; and

the quadrature beam components for each antenna element includes a quadrature component corresponding to each beam.

10. The method of claim 1, wherein:

multiple users are assigned to each beams beam using frequency division multiplexing; and

the user data is encoded into each beam using a frequency shift key coding technique.

11. The method of claim 1, wherein:

multiple users are assigned to each beam using frequency division multiplexing; and

the user data is encoded into each beam using a phase shift key coding technique.

12. The method of claim 1, wherein;

multiple users are assigned to each beams using orthogonal multiplexing; and

the user data is encoded into each beam using a phase shift key coding technique.

13. A computer storage medium comprising computer executable instructions for performing the method of claim 1.

14. An apparatus configured to perform the method of claim 1.

15. The method of claim 8, wherein the step of encoding each beam with the data for the corresponding users further comprises the step of encoding the beams with frequencies using a frequency shift key coding technique.

16. The method of claim 8, wherein the step of encoding each beam with the data for the corresponding users further comprises the step of encoding the beams with frequencies using a phase shift key coding technique.

17. The method of claim 8, the step of encoding each beam with the data for the corresponding users further comprises the step of encoding the beams using an orthogonal coding technique.

18. A computer storage medium comprising computer executable instructions for performing the method of claim 8.

19. An apparatus configured to perform the method of claim 8.

20. A multi-beam phased array antenna system comprising:

a plurality of antenna elements;

a phase and gain control device associated with each antenna element; and

a beam forming computer configured to generate control signals to drive the phase and gain control devices to create multiple beams, wherein;

each beam is assigned data corresponding to users located within a coverage associated with the corresponding beam,

a control signal for each antenna element comprises a total gain and a total phase shift,

the control signal control signal for each antenna element comprises a vector sum of beam components in which one beam component corresponds to each beam, and

each beam component comprises a vector sum of data signals for users assigned to the corresponding beam, wherein each data signal comprises a coding parameter representing data for an associated user.

21. The antenna system of claim 20, wherein:

the control signal for each antenna element comprises an in-phase component defined by a sum of in-phase beam components for the corresponding antenna element;

the control signal for each antenna element comprises a quadrature component defined by a sum of quadrature beam components for the corresponding antenna element; and

the control signal for each antenna element comprises a total gain and a total phase shift for the antenna element bused on the in-phase and quadrature components for the corresponding antenna element.

22. The antenna system of claim 21, wherein:

the in-phase beam components for each antenna element includes an in-phase component corresponding to each beam; and

the quadrature beam components for each antenna element includes a quadrature component corresponding to each beam.

23. The antenna system of claim 20 wherein the coding parameters are embedded in the in-phase and quadrature beam components.

24. The method of claim 20, wherein:

multiple users are assigned to each beam using frequency division multiplexing; and

the user data is encoded into each beam using a frequency shift key coding technique.

25. The method of claim 20, wherein:

multiple users are assigned to each beam using frequency division multiplexing; and

the user data is encoded into each beam using a phase shift key coding technique.

26. The method of claim 20, wherein:

multiple users are assigned to each beam using orthogonal multiplexing; and

the user data is encoded into each beam using a phase shift key coding technique.

27. The method of claim 20, wherein the user data is encoded into each beam using coding parameters that are changed on demand.

28. A multi-beam phased array antenna system comprising:

a plurality of antenna elements;

a phase and gain control device associated with each antenna element;

a code selector configured to identify desired coding parameter sets;

a beam selector configured to identify desired beam sets; and

a beam forming computer configured to generate control signals to drive the phase and gain control devices to create multiple beams, wherein;

each beam is assigned data corresponding to users located within a coverage associated with the corresponding beam,

a control signal for each antenna element comprises a total gain and a total phase shift, and

the control signal control signal for each antenna element comprises a vector sum of beam components in which one beam component corresponds to each beam, and

each beam component comprises a vector sum of data signals for users assigned to the corresponding beam, wherein each data signal comprises a coding parameter representing data for an associated user.

29. The antenna system of claim 28, wherein:

multiple users are assigned to each beam using frequency division multiplexing; and

the user data is encoded into each beam using a frequency shift key coding technique.

30. The method antenna system of claim 28, wherein:

multiple users are assigned to each beam using frequency division multiplexing; and

the user data is encoded into each beam using a phase shift key coding technique.

31. The antenna system of claim 28, wherein:

multiple users are assigned to each beam using orthogonal multiplexing; and

the user data is encoded into each beam using a phase shift key coding technique.

32. In a beam former for use with a phased array antenna system, an improvement comprising:

the beam former being operative for coding the data and combining the coded data into control signals to drive a plurality of antenna elements to broadcast a plurality of beams, wherein each beam carries data assigned to a plurality of users located within a coverage area associated with the beam, and the control signal for each antenna element comprises a total gain and a total phase shift comprising a vector sum of beam components in which each beam component is associated with a corresponding beam.

33. The beam former of claim 32, wherein the control signal for each antenna element comprises a vector sum of beam components comprising a beam component corresponding to each beam.

34. The beam former of claim 32, wherein each beam component comprises a vector sum of data signals for users assigned to the corresponding beam.

35. The beam former of claim 32 wherein:

multiple users are assigned to each beam using frequency division multiplexing; and

the user data is encoded into each beam using a frequency shift key coding technique.

37. The beam former of claim 32, wherein:

multiple users are assigned to each beam using orthogonal multiplexing; and

the user data is encoded into each beam using a phase shift key coding technique.

36. The method beam former of 32, wherein:

multiple users are assigned to each beam using frequency division multiplexing; and

the user data is encoded into each beam using a phase shift key coding technique.