Method and system for collaborated beamforming for reducing interference

• US 20070087694A1
• Filed: 05/23/2006
• Published: 04/19/2007
• Est. Priority Date: 10/18/2005
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Navini Networks, Inc. (Cisco Systems, Inc.)
• Inventors: Grabner, John, Jin, Hang
• Granted Patent: US 7,680,457 B2
• Time in Patent Office: Days
• US Class Current: 455/63.100
• CPC Class Codes: H04B 7/0617 for beam forming

Abstract

A method is disclosed for reducing interferences in a wireless communication system. First, in one or more cells, a plurality of frequency-time frames are generated each having at least one predetermined frequency-time open window unused for desired wireless communications. The interference information is derived from the predetermined open windows of the frames. The interference for incoming signals is reduced by calculating beamforming weights using the observed interference information.

Claims

1. A method for generating beamforming weights in wireless communication comprising:

generating, in one or more cells, a plurality of frequency-time frames each having at least one predetermined frequency-time open window unused for desired wireless communications;

observing interference information through the predetermined open windows of the frames;

determining an existence of interference through incoming signals;

calculating beamforming weights by using the observed interference information for reducing the interference accompanying the incoming signals.

2. The method of claim 1, wherein the frequency-time open window is a portion of an uplink sounding region according to IEEE 802.16 standard with no connection identifier assigned thereto.

3. The method of claim 1, wherein the frequency-time open window is a plurality of symbols between two usable zones according to IEEE 802.16 standard with no connection identifier assigned thereto.

4. The method of claim 1, wherein the frequency-time open window is a safety zone according to IEEE 802.16 standard.

5. The method of claim 1, wherein the frequency-time open window is at least one carrier earmarked for interference observation according to IEEE 802.16 standard

6. The method of claim 1, wherein the plurality of frequency-time frames are in a pseudo-random sequence, each having different patterns for the open windows contained therein.

7. The method of claim 1, wherein the observing further includes prioritizing the frames based on a receiving sequence.

8. The method of claim 1, wherein the calculating further includes calculating the beamforming weights using interference information derived from a predetermined region enclosing the open windows having similar time and frequencies.

9. The method of claim 8, wherein a boundary of the predetermined region varies dynamically.

10. The method of claim 1, wherein the determining further includes determining spatial signature based on the incoming signals for identifying relevant interference information.

11. The method of claim 1, further comprising considering uplink and downlink resource allocations of one or more neighboring cells for the incoming signals.

12. A method for reducing interferences for wireless communications operated by one or more base stations in a wireless communications system, comprising:

providing each cell in a plurality of cells operating under at least one base station a selected set from a plurality set of frequency-time frames, each frame having one or more predetermined frequency-time open windows unused for desired wireless communications;

observing interference information, for each cell, through the predetermined open windows of the frames unused for the desired wireless communications; and

determining beamforming weights by using the observed interference information for reducing the interference accompanying the desired wireless communications,

wherein the set of frequency-time frames for each cell have different patterns for the frequency-time open windows.

13. The method of claim 12, wherein the frequency-time open window is a portion of an uplink sounding region according to IEEE 802.16 standard with no connection identifier assigned thereto.

14. The method of claim 12, wherein the frequency-time open window is a plurality of symbols between two usable zones according to IEEE 802.16 standard with no connection identifier assigned thereto.

15. The method of claim 12, wherein the frequency-time open window is at least one carrier earmarked for interference observation according to IEEE 802.16 standard

16. The method of claim 12, wherein the frequency-time open window is a safety zone according to IEEE 802.16 standard.

17. The method of claim 12, wherein the frequency-time frames are in a pseudo-random sequence.

18. The method of claim 12, wherein the providing further includes providing different patterns of the open windows for neighboring cells for a predetermined frame.

19. The method of claim 12, wherein the observing further includes prioritizing the frames based on a receiving sequence.

20. The method of claim 12, wherein the determining further includes calculating the beamforming weights using interference information derived from a predetermined region enclosing the open windows having similar time and frequencies.

21. A method for reducing interferences for wireless communications operated by one or more base stations in a wireless communications system, comprising:

providing each cell in a plurality of cells operating under at least one base station a selected pseudo random sequence of frequency-time frames, each frame having one or more predetermined frequency-time open windows unused for desired wireless communications;

observing interference information, for each cell, through the predetermined open windows of the frames unused for the desired wireless communications; and

determining beamforming weights by using the observed interference information for reducing the interference accompanying the desired wireless communications,

wherein the set of frequency-time frames for each cell have different patterns for the frequency-time open windows, and

wherein different patterns of the open windows are used for neighboring cells for a predetermined frame.

22. The method of claim 21, wherein the frequency-time open window is a portion of an uplink sounding region according to IEEE 802.16 standard with no connection identifier assigned thereto.

23. The method of claim 21, wherein the frequency-time open window is a plurality of symbols between two usable zones according to IEEE 802.16 standard with no connection identifier assigned thereto.

24. The method of claim 21, wherein the frequency-time open window is a safety zone according to IEEE 802.16 standard.

25. The method of claim 21, wherein the frequency-time open window is at least one carrier earmarked for interference observation according to IEEE 802.16 standard.

26. The method of claim 21, wherein the observing further includes prioritizing the frames based on a receiving sequence.

27. The method of claim 21, wherein the determining further includes calculating the beamforming weights using interference information derived from a predetermined region enclosing the open windows having similar time and frequencies.