Cooperative Wireless Communications

• US 20080285480A1
• Filed: 11/09/2007
• Published: 11/20/2008
• Est. Priority Date: 10/07/2004
• Status: Active Grant

• Current Assignee: Polytechnic University (New York University)
• Original Assignee: Polytechnic University (New York University)
• Inventors: Tao, Zhifeng, Panwar, Shivendra S., Liu, Pei
• Granted Patent: US 8,175,003 B2
• Time in Patent Office: Days
• US Class Current: 370/253
• CPC Class Codes: H04L 45/121 by minimising delays
• CPC Class Codes: H04W 40/00 Communication routing or communication path finding
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

When it is advantageous to do so, a wireless LAN station sends data packets to a destination station via an intermediate station, instead of to the destination station directly. That is, the intermediate station, which serves as a helper to the source, forwards packets received from the source station to the intended destination station. This cooperative data transmission approach can result in system performance improvement, as long as the total time consumed by two-hop transmission (i.e., transmission via the helper station) is less than direct transmission. Such a determination may be made using rate information stored at each station. Specifically, using the rate information, signaling needed to set up a transmission, the amount of data to be transmitted, etc., transmitting the data directly and via a help station may be compared.

Claims

1-14. -14. (canceled)

15. A method for use by a listening wireless LAN device that hears a transmission from a sending wireless LAN device, for discovering wireless LAN conditions, the method comprising:

estimating a channel condition between the sending wireless LAN device and the listening wireless LAN device, wherein the channel condition includes a data rate; and

storing the data rate, in association with an identifier of the sending wireless LAN device, as a data rate between the sending wireless LAN device and the listening wireless LAN device.

16. The method of claim 15 wherein the channel condition is estimated based on a power strength of the transmission received by the listening wireless LAN device.

17. The method of claim 15 further comprising at least one step selected from the group consisting of:

storing a time that the transmission was heard, in association with the identifier of the sending wireless LAN device; and

storing a second data rate, in association with an identifier of the sending wireless LAN device, as a data rate between the listening wireless LAN device and the sending wireless LAN device, wherein the second data rate is the same as the data rate.

19. The method of claim 15 wherein the identifier of the sending wireless LAN device is a MAC address of the sending wireless LAN device.

27. The method of claim 15 further comprising:

storing the number of potential failures associated with the sending wireless LAN device.

28. The method of claim 27 further comprising:

determining if the stored number of sequential failures associated with the sending wireless LAN exceeds a predefined value, and if the number of sequential failures exceeds the predefined value, then deleting the stored data rate, the stored identifier, and the stored number of potential failures.

29. The method of claim 17, further comprising:

determining, based on the stored timestamp, if a predefined amount of time has been exceeded, and, if the predefined amount of time has been exceeded, then deleting the stored data rate, the stored identifier, and the stored timestamp.

30. The method of claim 17 wherein storing a time that the transmission was heard comprises:

determining a first time needed to transmit the data from the sending wireless LAN device directly to the listening wireless LAN device;

determining a second time needed to transmit the data from the sending wireless LAN device to the listening wireless LAN device via an intermediate wireless LAN device;

determining whether or not the second time is less than the first time; and

if the second time is determined to be less than the first time, then transmitting the data from the sending wireless LAN device to the listening wireless LAN device via the intermediate wireless LAN device.

31. The method of claim 30 further comprising:

if the second time is not less than the first time, then transmitting the data from the sending wireless LAN device to the listening wireless LAN device directly.

18. (canceled)

20-26. -26. (canceled)

32. A computer-readable medium for use by a listening wireless LAN device that hears a transmission from a sending wireless LAN device, for discovering wireless LAN conditions, the computer-readable medium comprising computer readable instructions to:

estimate a channel condition between the sending wireless LAN device and the listening wireless LAN device, wherein the channel condition includes a data rate; and

store the data rate, in association with an identifier of the sending wireless LAN device, as a data rate between the sending wireless LAN device and the listening wireless LAN device.

33. The computer readable medium of claim 32 wherein the channel condition is estimated based on a power strength of the transmission received by the listening wireless LAN device.

34. The computer readable medium of claim 32 further comprising at least one computer readable instruction selected from the group consisting of:

store a time that the transmission was heard, in association with the identifier of the sending wireless LAN device; and

store a second data rate, in association with an identifier of the sending wireless LAN device, as a data rate between the listening wireless LAN device and the sending wireless LAN device, wherein the second data rate is the same as the data rate.

35. The computer readable medium of claim 32 wherein the identifier of the sending wireless LAN device is a MAC address of the sending wireless LAN device.

36. The computer readable medium of claim 32 further comprising computer readable instructions to:

store the number of potential failures associated with the sending wireless LAN device.

37. The computer readable medium of claim 36 further comprising computer readable instructions to:

determine if the stored number of sequential failures associated with the sending wireless LAN exceeds a predefined value, and if the number of sequential failures exceeds the predefined value, then deleting the stored data rate, the stored identifier, and the stored number of potential failures.

38. The computer readable medium of claim 34, further comprising computer readable instructions to:

determine, based on the stored timestamp, if a predefined amount of time has been exceeded, and, if the predefined amount of time has been exceeded, then deleting the stored data rate, the stored identifier, and the stored timestamp.

39. The computer readable medium of claim 34 wherein the computer readable instructions to store a time that the transmission was heard comprise computer readable instructions to:

determine a first time needed to transmit the data from the sending wireless LAN device directly to the listening wireless LAN device;

determine a second time needed to transmit the data from the sending wireless LAN device to the listening wireless LAN device via an intermediate wireless LAN device;

determine whether or not the second time is less than the first time; and

transmit the data from the sending wireless LAN device to the listening wireless LAN device via the intermediate wireless LAN device, if the second time is determined to be less than the first time.

40. The computer readable medium of claim 39 further comprising computer readable instructions to:

transmit the data from the sending wireless LAN device to the listening wireless LAN device directly, if the second time is not less than the first time.

41. A method for use by a listening wireless LAN device that hears transmissions from a plurality of sending wireless LAN devices, for discovering wireless LAN conditions, the method comprising:

estimating a channel condition between each of the plurality of sending wireless LAN device and the listening wireless LAN device, wherein the channel condition includes a data rate; and

storing the data rate, in association with an identifier of each of the plurality of sending wireless LAN device, as a data rate between each multiple sending wireless LAN device and the listening wireless LAN device.

42. The method of claim 41 wherein the channel condition between each multiple sending wireless LAN device is estimated based on a power strength of the transmission received by the listening wireless LAN device.

43. The method of claim 41 further comprising determining which transmission between each multiple sending wireless LAN device and the listening wireless LAN device yields the best bit error rate/packet error rate performance.

44. A computer-readable medium for use by a listening wireless LAN device that hears transmissions from multiple sending wireless LAN devices, for discovering wireless LAN conditions, the computer readable medium comprising computer readable instructions to:

estimate a channel condition between each multiple sending wireless LAN device and the listening wireless LAN device, wherein the channel condition includes a data rate; and

store the data rate, in association with an identifier of each multiple sending wireless LAN device, as a data rate between each multiple sending wireless LAN device and the listening wireless LAN device.

45. The computer readable medium of claim 44 wherein the channel condition between each multiple sending wireless LAN device is estimated based on a power strength of the transmission received by the listening wireless LAN device.

46. The computer readable medium of claim 44 further comprising computer readable instructions to:

determine which transmission between each multiple sending wireless LAN device and the listening wireless LAN device yields the best bit error rate/packet error rate performance.