Method and apparatus for controlling wireless medium congestion by adjusting contention window size and disassociating selected mobile stations

• US 20060187840A1
• Filed: 10/31/2005
• Published: 08/24/2006
• Est. Priority Date: 02/02/2005
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Cuffaro, Angelo, Ali, Ahmed
• Granted Patent: US 7,787,366 B2
• Time in Patent Office: Days
• US Class Current: 370/235
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 48/06 based on traffic conditions
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 76/30 Connection release
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A method and apparatus for alleviating congestion of a wireless medium used by an access point (AP) and a plurality of wireless transmit/receive units (WTRUs) is disclosed. If congestion is determined to exist on the wireless medium, a determination is then made as to whether there are any low priority traffic streams established between the AP and at least one of the WTRUs. If there are no low priority traffic streams established between the AP and at least one of the WTRUs, selected ones of the associated WTRUs are disassociated with the AP based on the amount of time spent by the WTRUs trying to transmit and retransmit unacknowledged packets or on a specific traffic stream access category. If low priority traffic streams have been established, the packet transmission delay associated with the low priority traffic streams is increased when congestion exists. Otherwise, the packet transmission delay is decreased.

Claims

1. In a wireless communication system including an access point (AP) and a plurality of wireless transmit/receive units (WTRUs) associated with the AP, a method of alleviating congestion comprising:

(a) determining whether congestion exists on a wireless medium used by the AP and the WTRUs;

(b) if congestion is determined to exist on the wireless medium, determining whether there are any low priority traffic streams established between the AP and at least one of the WTRUs; and

(c) if there are no low priority traffic streams established between the AP and at least one of the WTRUs, disassociating selected ones of the associated WTRUs based on the amount of time spent by the WTRUs trying to transmit and retransmit unacknowledged packets.

2. The method of claim 1 wherein the low priority traffic streams include a background access category traffic stream.

3. The method of claim 1 wherein the low priority traffic streams include a best effort access category traffic stream.

4. The method of claim 1 further comprising:

(d) the AP updating an enhanced distributed channel access (EDCA) parameter set included in frames transmitted by the AP.

5. The method of claim 1 wherein the wireless communication system is a wireless local area network (WLAN).

6. In a wireless communication system including an access point (AP) and a plurality of wireless transmit/receive units (WTRUs) associated with the AP, a method of alleviating congestion comprising:

(a) determining whether congestion exists on a wireless medium used by the AP and the WTRUs;

(b) decreasing a packet transmission delay associated with low priority traffic streams when congestion is determined not to exist on the wireless medium; and

(c) increasing the packet transmission delay associated with the low priority traffic streams when congestion is determined to exist on the wireless medium.

7. The method of claim 6 further comprising

(d) if there are no low priority traffic streams established between the AP and at least one of the WTRUs, disassociating selected ones of the associated WTRUs based on the amount of time spent by the WTRUs trying to transmit and retransmit unacknowledged packets.

8. The method of claim 6 further comprising:

(d) if the packet transmission delay reaches a maximum value, disassociating selected ones of the associated WTRUs based on the amount of time spent by the WTRUs trying to transmit and retransmit unacknowledged packets.

9. The method of claim 6 further comprising:

(d) if the packet transmission delay reaches a maximum value, disassociating selected ones of the associated WTRUs based on a specific traffic stream access category.

10. The method of claim 6 further comprising:

(d) the AP updating an enhanced distributed channel access (EDCA) parameter set included in frames transmitted by the AP.

11. The method of claim 6 wherein the low priority traffic streams include a background access category traffic stream.

12. The method of claim 6 wherein the low priority traffic streams include a best effort access category traffic stream.

13. The method of claim 6 wherein the wireless communication system is a wireless local area network (WLAN).

14. In a wireless communication system including an access point (AP) and a plurality of wireless transmit/receive units (WTRUs) associated with the AP, a method of alleviating congestion comprising:

(a) determining whether congestion exists on a wireless medium used by the AP and the WTRUs;

(b) if congestion is determined to exist on the wireless medium, determining whether there are any low priority traffic streams established between the AP and at least one of the WTRUs; and

(c) if there are no low priority traffic streams established between the AP and at least one of the WTRUs, disassociating selected ones of the associated WTRUs based on a specific traffic stream access category.

15. The method of claim 14 wherein the low priority traffic streams include a background access category traffic stream.

16. The method of claim 14 wherein the low priority traffic streams include a best effort access category traffic stream.

17. The method of claim 14 further comprising:

(d) the AP updating an enhanced distributed channel access (EDCA) parameter set included in frames transmitted by the AP.

18. The method of claim 14 wherein the wireless communication system is a wireless local area network (WLAN).

19. An access point (AP) for alleviating congestion in a wireless medium used by the AP to communicate with a plurality of wireless transmit/receive units (WTRUs), the AP comprising:

(a) a receiver for receiving packets transmitted by the WTRUs over the wireless medium;

(b) a transmitter for transmitting packets to the WTRUs over the wireless medium;

(c) a processor in communication with the receiver and the transmitter for determining whether congestion exists on the wireless medium; and

(d) a WTRU database in communication with the processor, wherein if congestion is determined by the processor to exist on the wireless medium, the processor determines whether there are any low priority traffic streams established between the AP and at least one of the WTRUs and, if there are no low priority traffic streams established between the AP and at least one of the WTRUs, the processor disassociates selected ones of the associated WTRUs listed in the WTRU database based on the amount of time spent by the WTRUs trying to transmit and retransmit unacknowledged packets.

20. The AP of claim 19 wherein the low priority traffic streams include a background access category traffic stream.

21. The AP of claim 19 wherein the low priority traffic streams include a best effort access category traffic stream.

22. The AP of claim 19 wherein the processor updates an enhanced distributed channel access (EDCA) parameter set included in frames transmitted by the transmitter.

23. The AP of claim 19 wherein the AP operates in a wireless local area network (WLAN).

24. An access point (AP) for alleviating congestion in a wireless medium used by the AP to communicate with a plurality of wireless transmit/receive units (WTRUs), the AP comprising:

(a) a receiver for receiving packets transmitted by the WTRUs over the wireless medium;

(b) a transmitter for transmitting packets to the WTRUs over the wireless medium; and

(c) a processor in communication with the receiver and the transmitter for determining whether congestion exists on the wireless medium, decreasing a packet transmission delay associated with low priority traffic streams when congestion is determined not to exist on the wireless medium, and increasing the packet transmission delay associated with the low priority traffic streams when congestion is determined to exist on the wireless medium.

28. The AP of claim 24 wherein the AP updates an enhanced distributed channel access (EDCA) parameter set included in frames transmitted by the AP.

29. The AP of claim 24 wherein the low priority traffic streams include a background access category traffic stream.

30. The AP of claim 24 wherein the low priority traffic streams include a best effort access category traffic stream.

31. The AP of claim 24 wherein the AP operates in a wireless local area network (WLAN).

25. The AP of claim further comprising:

(d) a WTRU database in communication with the processor, wherein if there are no low priority traffic streams established between the AP and at least one of the WTRUs, the processor disassociates selected ones of the associated WTRUs listed in the WTRU database based on the amount of time spent by the WTRUs trying to transmit and retransmit unacknowledged packets.

26. The AP of claim 25 wherein if the packet transmission delay reaches a maximum value, the processor disassociates selected ones of the associated WTRUs listed in the WTRU database based on the amount of time spent by the WTRUs trying to transmit and retransmit unacknowledged packets.

27. The AP of claim 25 wherein if the packet transmission delay reaches a maximum value, the processor disassociates selected ones of the associated WTRUs listed in the WTRU database based on a specific traffic stream access category.

32. An access point (AP) for alleviating congestion in a wireless medium used by the AP to communicate with a plurality of wireless transmit/receive units (WTRUs), the AP comprising:

(a) a receiver for receiving packets transmitted by the WTRUs over the wireless medium;

(b) a transmitter for transmitting packets to the WTRUs over the wireless medium;

(c) a processor in communication with the receiver and the transmitter for determining whether congestion exists on the wireless medium; and

(d) a WTRU database in communication with the processor, wherein if congestion is determined by the processor to exist on the wireless medium, the processor determines whether there are any low priority traffic streams established between the AP and at least one of the WTRUs and, if there are no low priority traffic streams established between the AP and at least one of the WTRUs, the processor disassociates selected ones of the associated WTRUs listed in the WTRU database based on based on a specific traffic stream access category.

33. The AP of claim 32 wherein the low priority traffic streams include a background access category traffic stream.

34. The AP of claim 32 wherein the low priority traffic streams include a best effort access category traffic stream.

35. The AP of claim 32 wherein the processor updates an enhanced distributed channel access (EDCA) parameter set included in frames transmitted by the transmitter.

36. The AP of claim 32 wherein the AP operates in a wireless local area network (WLAN).

37. In an access point (AP) for alleviating congestion in a wireless medium used by the AP to communicate with a plurality of wireless transmit/receive units (WTRUs), an integrated circuit (IC) comprising:

(a) a receiver for receiving packets transmitted by the WTRUs over the wireless medium;

(b) a transmitter for transmitting packets to the WTRUs over the wireless medium;

(c) a processor in communication with the receiver and the transmitter for determining whether congestion exists on the wireless medium; and

(d) a WTRU database in communication with the processor, wherein if congestion is determined by the processor to exist on the wireless medium, the processor determines whether there are any low priority traffic streams established between the AP and at least one of the WTRUs and, if there are no low priority traffic streams established between the AP and at least one of the WTRUs, the processor disassociates selected ones of the associated WTRUs listed in the WTRU database based on the amount of time spent by the WTRUs trying to transmit and retransmit unacknowledged packets.

38. The IC of claim 37 wherein the low priority traffic streams include a background access category traffic stream.

39. The IC of claim 37 wherein the low priority traffic streams include a best effort access category traffic stream.

40. The IC of claim 37 wherein the processor updates an enhanced distributed channel access (EDCA) parameter set included in frames transmitted by the transmitter.

41. The IC of claim 37 wherein the AP operates in a wireless local area network (WLAN).

42. In an access point (AP) for alleviating congestion in a wireless medium used by the AP to communicate with a plurality of wireless transmit/receive units (WTRUs), an integrated circuit (IC) comprising:

(a) a receiver for receiving packets transmitted by the WTRUs over the wireless medium;

(b) a transmitter for transmitting packets to the WTRUs over the wireless medium; and

(c) a processor in communication with the receiver and the transmitter for determining whether congestion exists on the wireless medium, decreasing a packet transmission delay associated with low priority traffic streams when congestion is determined not to exist on the wireless medium, and increasing the packet transmission delay associated with the low priority traffic streams when congestion is determined to exist on the wireless medium.

46. The IC of claim 42 wherein the AP updates an enhanced distributed channel access (EDCA) parameter set included in frames transmitted by the AP.

47. The IC of claim 42 wherein the low priority traffic streams include a background access category traffic stream.

48. The IC of claim 42 wherein the low priority traffic streams include a best effort access category traffic stream.

49. The IC of claim 42 wherein the AP operates in a wireless local area network (WLAN).

43. The IC of claim further comprising:

(d) a WTRU database in communication with the processor, wherein if there are no low priority traffic streams established between the AP and at least one of the WTRUs, the processor disassociates selected ones of the associated WTRUs listed in the WTRU database based on the amount of time spent by the WTRUs trying to transmit and retransmit unacknowledged packets.

44. The IC of claim 43 wherein if the packet transmission delay reaches a maximum value, the processor disassociates selected ones of the associated WTRUs listed in the WTRU database based on the amount of time spent by the WTRUs trying to transmit and retransmit unacknowledged packets.

45. The IC of claim 43 wherein if the packet transmission delay reaches a maximum value, the processor disassociates selected ones of the associated WTRUs listed in the WTRU database based on a specific traffic stream access category.

50. In an access point (AP) for alleviating congestion in a wireless medium used by the AP to communicate with a plurality of wireless transmit/receive units (WTRUs), an integrated circuit (IC) comprising:

(a) a receiver for receiving packets transmitted by the WTRUs over the wireless medium;

(b) a transmitter for transmitting packets to the WTRUs over the wireless medium;

(c) a processor in communication with the receiver and the transmitter for determining whether congestion exists on the wireless medium; and

(d) a WTRU database in communication with the processor, wherein if congestion is determined by the processor to exist on the wireless medium, the processor determines whether there are any low priority traffic streams established between the AP and at least one of the WTRUs and, if there are no low priority traffic streams established between the AP and at least one of the WTRUs, the processor disassociates selected ones of the associated WTRUs listed in the WTRU database based on based on a specific traffic stream access category.

51. The IC of claim 50 wherein the low priority traffic streams include a background access category traffic stream.

52. The IC of claim 50 wherein the low priority traffic streams include a best effort access category traffic stream.

53. The IC of claim 50 wherein the processor updates an enhanced distributed channel access (EDCA) parameter set included in frames transmitted by the transmitter.

54. The IC of claim 50 wherein the AP operates in a wireless local area network (WLAN).

55. In a wireless communication system including an access point (AP) and a plurality of wireless transmit/receive units (WTRUs) associated with the AP, a method of alleviating congestion comprising:

(a) determining whether congestion exists on a wireless medium used by the AP and the WTRUs;

(b) decreasing the size of an arbitration inter-frame space (AIFS) associated with low priority traffic streams when congestion is determined not to exist on the wireless medium; and

(c) increasing the size of the AIFS associated with the low priority traffic streams when congestion is determined to exist on the wireless medium.

56. The method of claim 55 wherein the AIFS is a packet transmission delay parameter.

57. An access point (AP) for alleviating congestion in a wireless medium used by the AP to communicate with a plurality ofwireless transmit/receive units (WTRUs), the AP comprising:

(a) a receiver for receiving packets transmitted by the WTRUs over the wireless medium;

(b) a transmitter for transmitting packets to the WTRUs over the wireless medium; and

(c) a processor in communication with the receiver and the transmitter for determining whether congestion exists on the wireless medium, decreasing the size of an arbitration inter-frame space (AIFS) associated with low priority traffic streams when congestion is determined not to exist on the wireless medium, and increasing the size of the AIFS associated with the low priority traffic streams when congestion is determined to exist on the wireless medium.

58. The AP of claim 57 wherein the AIFS is a packet transmission delay parameter.

59. In an access point (AP) for alleviating congestion in a wireless medium used by the AP to communicate with a plurality of wireless transmit/receive units (WTRUs), an integrated circuit (IC) comprising:

(a) a receiver for receiving packets transmitted by the WTRUs over the wireless medium;

(b) a transmitter for transmitting packets to the WTRUs over the wireless medium; and

(c) a processor in communication with the receiver and the transmitter for determining whether congestion exists on the wireless medium, decreasing the size of an arbitration inter-frame space (AIFS) associated with low priority traffic streams when congestion is determined not to exist on the wireless medium, and increasing the size of the AIFS associated with the low priority traffic streams when congestion is determined to exist on the wireless medium.

60. The IC of claim 59 wherein the AIFS is a packet transmission delay parameter.