High density WLAN system

• US 20060092889A1
• Filed: 10/29/2004
• Published: 05/04/2006
• Est. Priority Date: 08/25/2004
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Amos, James A., Anderson, Fred J., Petsko, David, Friedmann, James Jay, Sloan, Donald I., Lyons, Daniel
• Granted Patent: US 7,529,218 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04W 16/08 Load shedding arrangements
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A method for controlling cell size associated with an access point that has a receive sensitivity and an output power. The method includes changing a start of packet threshold and/or a clear channel assessment threshold to vary the cell size of the access point.

Claims

1. A method for controlling cell size associated with an access point having a receive sensitivity and an output power, comprising:

changing at least one of a start of packet threshold and a clear channel assessment threshold to vary the cell size of the access point.

2. The method for controlling cell size associated with an access point of claim 1, wherein the output power of the access point is maintained.

3. The method for controlling cell size associated with an access point of claim 1, wherein at least one of a start of packet threshold and a clear channel assessment threshold are changed relative to the output power.

4. The method for controlling cell size associated with an access point of claim 1, wherein a range of a lower data rate is restricted without shrinking the coverage area of a higher data rate.

5. The method for controlling cell size associated with an access point of claim 1, further comprising raising at least one of the start of packet threshold and the clear channel assessment threshold above the minimum receive sensitivity of the access point.

6. The method for controlling cell size associated with an access point of claim 1, further comprising increasing cell size by decreasing at least one of the start of packet threshold and the clear channel assessment threshold.

7. The method for controlling cell size associated with an access point of claim 1, further comprising decreasing cell size by increasing at least one of the start of packet threshold and the clear channel assessment threshold.

8. The method for controlling cell size associated with an access point of claim 1, wherein the access point is assigned to the same carrier frequency as another access point.

9. The method for controlling cell size associated with an access point of claim 1, further comprising:

tracking a change in output power with the start of packet and clear channel assessment thresholds;

wherein changing the output power does not change the cell size, so long as the output power is maintained above a minimum level that prevents an inadequate received signal level at a client within the cell.

10. A method for operating a high density wireless local area network, comprising:

assigning multiple access points having receive sensitivities and output powers to the same carrier frequency;

controlling cell sizes associated with the access points by changing at least one of a start of packet threshold and a clear channel assessment threshold to vary the cell sizes of the access points.

11. The method for operating a high density wireless local area network of claim 10, wherein the output powers of the access points are maintained.

12. The method for operating a high density wireless local area network of claim 10, wherein at least one of the start of packet threshold and the clear channel assessment threshold are changed relative to the output powers.

13. The method for operating a high density wireless local area network of claim 10, wherein a range of a lower data rate is restricted without shrinking the coverage area of a higher data rate.

14. The method for operating a high density wireless local area network of claim 10, further comprising raising at least one of the start of packet thresholds and the clear channel assessment thresholds above the minimum receive sensitivities of the access points.

15. The method for operating a high density wireless local area network of claim 10, further comprising increasing cell sizes by decreasing at least one of the start of packet thresholds and the clear channel assessment thresholds.

16. The method for operating a high density wireless local area network of claim 10, further comprising decreasing cell sizes by increasing at least one of the start of packet thresholds and the clear channel assessment thresholds.

17. The method for operating a high density wireless local area network of claim 10, further comprising:

tracking changes in output powers with the start of packet and clear channel assessment thresholds;

wherein changing the output powers does not change the cell sizes, so long as the output powers are maintained above a minimum level that prevents an inadequate received signal level at a client within the cells.

18. An access point, comprising:

a transceiver configured for engaging in wireless communications with clients, and including a transmitter having an output power and a receiver having a receive sensitivity; and

a controller coupled to the transceiver and configured to control the operation of the transceiver when engaging in wireless communications with the clients, and including a processor configured for executing program code and a memory configured for storing the program code and at least one a start of packet threshold and a clear channel assessment threshold;

wherein at least one of the start of packet threshold and the clear channel assessment threshold is varied to control the cell size of the access point.

19. The access point of claim 18, wherein the output power of the transmitter is maintained.

20. The access point of claim 18, wherein at least one of a start of packet threshold and a clear channel assessment threshold are changed relative to the output power.

21. The access point of claim 18, wherein a range of a lower data rate is restricted without shrinking the coverage area of a higher data rate.

22. The access point of claim 18, wherein at least one of the start of packet threshold and the clear channel assessment threshold is raised above the minimum receive sensitivity of the access point.

23. The access point of claim 18, wherein the cell size is increased by decreasing at least one of the start of packet threshold and the clear channel assessment threshold.

24. The access point of claim 18, wherein the cell size is decreased by increasing at least one of the start of packet threshold and the clear channel assessment threshold.

25. The access point of claim 18, wherein the access point is assigned to the same carrier frequency as another access point.

26. The access point of claim 18, wherein the start of packet and clear channel assessment thresholds track a change in output power;

and

wherein changing the output power does not change the cell size, so long as the output power is maintained above a minimum level that prevents an inadequate received signal level at a client within the cell.

27. A high density wireless local area network, comprising:

a first access point including a first transmitter having an output power, a first receiver having a receive sensitivity, a first processor configured for executing program code to control the operation of the first transmitter and the first receiver when engaging in wireless communications with clients, and a first memory configured for storing the program code and at least one of a start of packet threshold and a clear channel assessment threshold;

a second access point including a second transmitter having an output power, a second receiver having a receive sensitivity, a second processor configured for executing program code to control the operation of the second transmitter and the second receiver when engaging in wireless communications with clients, and a second memory configured for storing the program code and at least one of a start of packet threshold and a clear channel assessment threshold;

wherein the first and second access points are assigned the same carrier frequency; and

wherein cell sizes associated with the first and second access points are controlled by changing at least one of the start of packet thresholds and the clear channel assessment thresholds to vary the cells sizes of the access points.

28. The high density wireless local area network of claim 27, wherein the output powers of the first and second transmitters are maintained.

29. The high density wireless local area network of claim 27, wherein at least one the start of packet thresholds and the clear channel assessment thresholds are changed relative to the output powers.

30. The high density wireless local area network of claim 27, wherein a range of a lower data rate is restricted without shrinking the coverage area of a higher data rate.

31. The high density wireless local area network of claim 27, wherein at the least one of the start of packet thresholds and clear channel assessment thresholds are raised above the minimum receive sensitivities of the first and second receivers.

32. The high density wireless local area network of claim 27, wherein the cell sizes are increased by decreasing at the least one of the start of packet thresholds and clear channel assessment thresholds.

33. The high density wireless local area network of claim 27, wherein the cell sizes are decreased by increasing at the least one of the start of packet thresholds and clear channel assessment thresholds.

34. The high density wireless local area network of claim 27, wherein the start of packet and clear channel assessment thresholds track changes in output powers;

and

wherein changing the output powers does not change the cell sizes, so long as the output powers are maintained above a minimum level that prevents an inadequate received signal level at a client within the cells.

35. A computer-readable medium of instructions for controlling cell size associated with an access point having a receive sensitivity and an output power, comprising:

means for changing at least one of a start of packet threshold and a clear channel assessment threshold to vary the cell size of the access point.

36. The computer-readable medium of instructions for controlling cell size associated with an access point of claim 35, wherein the output power of the access point is maintained.

37. The computer-readable medium of instructions for controlling cell size associated with an access point of claim 35, wherein at least one of a start of packet threshold and a clear channel assessment threshold are changed relative to the output power.

38. The computer-readable medium of instructions for controlling cell size associated with an access point of claim 35, wherein a range of a lower data rate is restricted without shrinking the coverage area of a higher data rate.

39. The computer-readable medium of instructions for controlling cell size associated with an access point of claim 35, further comprising means for raising at least one of the start of packet threshold and the clear channel assessment threshold above the minimum receive sensitivity of the access point.

40. The computer-readable medium of instructions for controlling cell size associated with an access point of claim 35, further comprising means for increasing cell size by decreasing at least one of the start of packet threshold and the clear channel assessment threshold.

41. The computer-readable medium of instructions for controlling cell size associated with an access point of claim 35, further comprising means for decreasing cell size by increasing at least one of the start of packet threshold and the clear channel assessment threshold.

42. The computer-readable medium of instructions for controlling cell size associated with an access point of claim 35, wherein the access point is assigned to the same carrier frequency as another access point.

43. The computer-readable medium of instructions for controlling cell size associated with an access point of claim 35, further comprising:

means for tracking a change in output power with the start of packet and clear channel assessment thresholds;

wherein changing the output power does not change the cell size, so long as the output power is maintained above a minimum level that prevents an inadequate received signal level at a client within the cell.

44. A computer-readable medium of instructions for operating a high density wireless local area network, comprising:

means for assigning multiple access points having receive sensitivities and output powers to the same carrier frequency;

means for controlling cell sizes associated with the access points by changing at least one of a start of packet threshold and a clear channel assessment threshold to vary the cell sizes of the access points.

45. The computer-readable medium of instructions for operating a high density wireless local area network of claim 44, wherein the output powers of the access points are maintained.

46. The computer-readable medium of instructions for operating a high density wireless local area network of claim 44, wherein at least one of the start of packet threshold and the clear channel assessment threshold are changed relative to the output powers.

47. The computer-readable medium of instructions for operating a high density wireless local area network of claim 44, wherein a range of a lower data rate is restricted without shrinking the coverage area of a higher data rate.

48. The computer-readable medium of instructions for operating a high density wireless local area network of claim 44, further comprising means for raising at least one of the start of packet thresholds and the clear channel assessment thresholds above the minimum receive sensitivities of the access points.

49. The computer-readable medium of instructions for operating a high density wireless local area network of claim 44, further comprising means for increasing cell sizes by decreasing at least one of the start of packet thresholds and the clear channel assessment thresholds.

50. The computer-readable medium of instructions for operating a high density wireless local area network of claim 44, further comprising means for decreasing cell sizes by increasing at least one of the start of packet thresholds and the clear channel assessment thresholds.

51. The computer-readable medium of instructions for operating a high density wireless local area network of claim 44, further comprising:

tracking changes in output powers with the start of packet and clear channel assessment thresholds;

wherein changing the output powers does not change the cell sizes, so long as the output powers are maintained above a minimum level that prevents an inadequate received signal level at a client within the cells.