Method and apparatus for sector based resource allocation in a broadhand wireless communications system

• US 6,400,697 B1
• Filed: 01/15/1998
• Issued: 06/04/2002
• Est. Priority Date: 01/15/1998
• Status: Expired due to Fees

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Shankaranarayanan, Nemmara K., Srivastava, Arty, Leung, Kin K.
• Primary Examiner(s): Vu, Huy D.
• Assistant Examiner(s): NGUYEN, STEVEN H D
• Application Number:
  US09/007,548
• Time in Patent Office: 1,601 Days
• Field of Search: 370/328, 370/329, 370/330, 370/336, 370/337, 370/345, 370/347-348, 455/446, 455/447, 455/448, 455/449, 455/67.3, 455/450-452, 455/443, 342/354, 342/360, 342/428-430
• US Class Current: 370/328
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

A method and apparatus for sector based resource allocation in a broadband wireless communications system. A service region is divided into a plurality of cells, and each cell is divided into a plurality of labeled sectors. Each label is selected to avoid an unacceptable amount of interference from any other sector while ensuring that at least two sectors in a cell share the same label. Transmissions are scheduled for a cell by assigning each communications site a channel, such as a time slot associated with the sector'"'"'s label. The transmissions are then communicated according to this schedule.

Claims

1. A method for scheduling communications in a communications system having a service region divided into a plurality of irregularly shaped cells, comprising the steps of:

scheduling transmissions, within a fixed wireless communications system, for communications sites within a first irregularly shaped cell, each communications site being located in one of a plurality of labeled sectors within the first irregularly shaped cell, each sector being labeled to avoid an unacceptable amount of interference from any other sector and each irregularly shaped cell having at least two sectors that share same label, wherein each communications site is scheduled to communicate said transmissions in a channel associated with the label of the communications site'"'"'s sector;

communicating said transmissions according to said scheduling using a multi-beam smart antenna and a directional terminal antenna; and

wherein the number of sectors in the first cell can be dynamically and flexibly changed by reconfiguring the smart antenna, without fixed, pre-assignment of channel patterns and antenna replacement after the communications system has been installed, while maintaining an even number of sectors, for increasing capacity and reducing interference in the system.

2. The method of claim 1, wherein adjacent sectors in the first cell do not have the same label.

3. The method of claim 2, wherein the sectors in the first cell are alternately labeled.

4. The method of claim 3, wherein no label in the first cell is used in any sector of any cell adjacent to the first cell.

5. The method of claim 1, wherein the channel is a time slot.

6. The method of claim 1, wherein said step of scheduling also schedules transmissions for a communications site in a channel associated with a second label, said second label being not used for any sector of any cell adjacent to the first cell.

7. The method of claim 1, wherein the number of sectors within the first cell is 6.

8. The method of claim 7, wherein the plurality of cells have a reuse pattern of 3 with a first type cell using labels 1 and 2, a second type cell using labels 3 and 4 and a third type cell using labels 5 and 6.

9. The method of claim 1, wherein the sectors in the first cell are of non-uniform size.

10. The method of claim 4, wherein the first cell and a second cell of the plurality of cells have different numbers of sectors based on traffic demand.

11. The method of claim 4, wherein the plurality of cells have a reuse pattern of 4.

12. A method for operating a communications system having a service region divided into a plurality of irregularly shaped cells, comprising the steps of:

communicating, within a fixed wireless communications system, in a first channel with a first plurality of communications sites within one of the plurality of irregularly shaped cells, each of said first plurality of communications sites being located in a first of a plurality of labeled sectors within the irregularly shaped cell, each sector being labeled to avoid an unacceptable amount of interference from any other sector and each irregularly shaped cell having at least two sectors that share the same label;

communicating in a second channel with a second plurality of communications sites within the irregularly shaped cell, each of said second plurality of communications sites being located in a second of the plurality of labeled sectors;

wherein said steps of communicating are performed using a multi-beam smart antenna and a directional terminal antenna; and

wherein the number of sectors in the cell can be dynamically and flexibly changed by reconfiguring the smart antenna, without fixed, pre-assignment of channel patterns and antenna replacement after the communications system has been installed, while maintaining an even number of sectors, for increasing capacity and reducing interference in the system.

13. The method of claim 12, wherein adjacent sectors in the first cell do not have the same label.

14. The method of claim 13, wherein the sectors in the first cell are alternately labeled.

15. The method of claim 14, wherein no label in the first cell is used in any sector of any cell adjacent to the first cell.

16. The method of claim 12, wherein the first and second channels are time slots.

17. The method of claim 12, wherein said step of communicating with a first plurality of communications sites also communicate in a third channel, said third channel not being used in an adjacent cell.

18. The method of claim 12, wherein the number of sectors within the cell is 6.

19. The method of claim 18, wherein the plurality of cells have a reuse pattern of 3 with a first type cell using labels 1 and 2, a second type cell using labels 3 and 4 and a third type cell using labels 5 and 6.

20. The method of claim 12, wherein the sectors in the cell are of non-uniform size.

21. The method of claim 15, wherein the cell and a second cell of the plurality of cells have different numbers of sectors based on traffic demand.

22. The method of claim 15, wherein the plurality of cells have a reuse pattern of 4.

23. A communications system having a plurality of irregularly shaped cells divided into a plurality of sectors, comprising:

a first communications unit, within a fixed wireless communications system, configured to communicate in a first channel with a first plurality of communications sites within one of the plurality of irregularly shaped cells, each of said first plurality of communications sites being located in a first of a plurality of labeled sectors within the irregularly shaped cell, each sector being labeled to avoid an unacceptable amount of interference from any other sector and each irregularly shaped cell having at least two sectors that share the same label;

a second communications unit, within a fixed wireless communications system, configured to communicate in a second channel with a second plurality of communications sites within the irregularly shaped cell, each of said second plurality of communications sites being located in a second of the plurality of labeled sectors;

a scheduler, within a fixed wireless communications system, for scheduling information for communication in each channel;

wherein said first and second communication units are configured to use a multi-beam smart antenna and a directional terminal antenna; and

wherein the number of sectors in the cell can be dynamically and flexibly changed by reconfiguring the smart antenna without fixed, pre-assignment of channel patterns and antenna replacement after the communications system has been installed, while maintaining an even number of sectors, for increasing capacity and reducing interference in the system.

24. The system of claim 23, wherein adjacent sectors in the first cell do not have the same label.

25. The system of claim 24, wherein the sectors in the first cell are alternately labeled.

26. The system of claim 25, wherein no label in the first cell is used in any sector of any cell adjacent to the first cell.

27. The system of claim 23, wherein the first and second channels are time slots.

28. The system of claim 23, wherein said first communications unit is also configured to communicate with the first plurality of communications sites in a third channel, said third channel not being used in an adjacent cell.

29. The system of claim 23, wherein the number of sectors within the first cell is 6.

30. The system of claim 23, wherein the plurality of cells have a reuse pattern of 3 with a first type cell using labels 1 and 2, a second type cell using labels 3 and 4 and a third type cell using labels 5 and 6.

31. The system of claim 23, wherein the sectors in the cell are of non-uniform size.

32. The system of claim 23, wherein the cell and a second cell of the plurality of cells have different numbers of sectors based on traffic demand.

33. The system of claim 23, wherein the plurality of cells have a reuse pattern of 4.