Cooperative wireless communications

• US 8,175,003 B2
• Filed: 11/09/2007
• Issued: 05/08/2012
• Est. Priority Date: 10/07/2004
• Status: Active Grant

• Current Assignee: Polytechnic University (New York University)
• Original Assignee: Polytechnic University (New York University)
• Inventors: Panwar, Shivendra S., Liu, Pei, Tao, Zhifeng
• Primary Examiner(s): Vu, Huy
• Assistant Examiner(s): Beyen, Zewdu A
• Application Number:
  US11/937,823
• Publication Number:
  US 20080285480A1
• Time in Patent Office: 1,642 Days
• Field of Search: None
• 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. A method for transmitting data over a wireless local area network (LAN), the method comprising:

estimating, based at least on a transmission between a source wireless device and an intermediate wireless device, a first data rate for communicating between the source wireless device and the intermediate wireless device;

estimating, based at least on a transmission between the intermediate wireless device and a destination wireless device, a second data rate for communicating between the intermediate wireless device and the destination wireless device;

receiving, by the intermediate wireless device, data sent from the source wireless device to the destination wireless device, the data including information identifying a third data rate for communicating between the source wireless device and the destination wireless device;

determining, by the intermediate wireless device, based on the first data rate, the second data rate, and the third data rate, whether to send the data from the intermediate wireless device to the destination wireless device;

and

sending the data from the intermediate wireless device to the destination wireless device in response to determining to send the data from the intermediate wireless device to the destination wireless device.

2. The method of claim 1, wherein estimating the first data rate comprises:

subtracting a fixed transmission power value from the detected power strength of the transmission between the source wireless device and the intermediate wireless device.

3. The method of claim 1, further comprising:

storing, in the intermediate wireless device, the first data rate and the second data rate; and

storing, in the intermediate wireless device, a time that the packet was received.

4. The method of claim 3, further comprising:

associating the time with information that identifies a media access card address of the source wireless device.

5. The method of claim 3, further comprising:

storing, in the intermediate wireless device, a number of failed attempts of the intermediate wireless device to send the data to the destination wireless device.

6. The method of claim 5, further comprising:

deleting the stored first data rate and the stored number of failed attempts in response to determining that the stored number of failed attempts exceeds a value.

7. The method of claim 5, further comprising:

deleting the stored first data rate and the stored number of failed attempts in response to determining that a predefined amount of time has elapsed since the stored time.

8. The method of claim 1, further comprising:

determining, by the intermediate wireless device, a first time needed to transmit the data from the source wireless device to the destination wireless device via the intermediate wireless device, the first time determined from at least the first data rate and the second data rate; and

determining, by the intermediate wireless device, a second time needed to transmit the data directly from the source wireless device to the destination wireless device;

wherein determining whether to send the data from the intermediate wireless device to the destination wireless device comprises determining whether the first time is less than the second time.

9. A non-transitory computer-readable storage medium having instructions stored thereon for transmitting data over a wireless local area network (LAN), the instructions comprising:

instructions to estimate, based at least on a transmission between a source wireless device and an intermediate wireless device, a first data rate for communicating between the source wireless device and the intermediate wireless device;

instructions to estimate, based at least on a transmission between the intermediate wireless device and a destination wireless device, a second data rate for communicating between the intermediate wireless device and the destination wireless device;

instructions to receive data sent from the source wireless device to the destination wireless device, the data including information identifying a third data rate for communicating between the source wireless device and the destination wireless device;

instructions to determine, by the intermediate wireless device, based on the first data rate, the second data rate, and the third data rate, whether to send the data from the intermediate wireless device to the destination wireless device; and

instructions to send the data from the intermediate wireless device to the destination wireless device in response to determining to send the data from the intermediate wireless device to the destination wireless device.

10. The computer-readable storage medium of claim 9, wherein the instructions to estimate the first data rate comprise:

instructions to subtract a fixed transmission power value from the detected power strength of the transmission between the source wireless device and the intermediate wireless device.

11. The computer-readable storage medium of claim 9, the instructions further comprising:

instructions to store, in the intermediate wireless device, the first data rate and the second data rate; and

instructions to store, in the intermediate wireless device, a time that the packet was received.

12. The computer-readable storage medium of claim 11, the instructions further comprising:

instructions to associate the time with information that identifies a media access card address of the source wireless device.

13. The computer-readable storage medium of claim 11, the instructions further comprising:

instructions to store, in the intermediate wireless device, a number of failed attempts of the intermediate wireless device to send the data to the destination wireless device.

14. The computer-readable storage medium of claim 13, the instructions further comprising:

instructions to delete the stored first data rate and the stored number of failed attempts in response to determining that the stored number of failed attempts exceeds a threshold.

15. The computer-readable storage medium of claim 13, the instructions further comprising:

instructions to delete the stored first data rate and the stored number of failed attempts in response to determining that an amount of time has elapsed since the stored time.

16. The computer-readable storage medium of claim 9, the instructions further comprising:

instructions to determine a first time needed to transmit the data from the source wireless device to the destination wireless device via the intermediate wireless device, the first time determined from at least the first data rate and the second data rate; and

instructions to determine a second time needed to transmit the data directly from the source wireless device to the destination wireless device;

wherein the instructions to determine whether to send the data from the intermediate wireless device to the destination wireless device comprise instructions to determine that the first time is less than the second time.

17. An intermediate wireless local area network (LAN) device, comprising:

a processor coupled to a computer-readable medium, the computer-readable medium having instructions stored thereon, the instructions comprising;

instructions to estimate, based at least on a transmission between a source wireless device and the intermediate wireless device, a first data rate for communicating with the source wireless device;

instructions to estimate, based at least on a transmission between the intermediate wireless device and a destination wireless device, a second data rate for communicating with the destination wireless device;

instructions to receive data sent from the source wireless device to the destination wireless device, the data including information identifying a third data rate for communicating between the source wireless device and the destination wireless device;

instructions to determine, based on the first data rate, the second data rate, and the third data rate, whether to send the data from the intermediate wireless device to the destination wireless device; and

instructions to send the data to the destination wireless device in response to determining to send the data to the destination wireless device.

18. The wireless device of claim 17, wherein the instructions to estimate the first data rate comprise:

instructions to subtract a fixed transmission power value from the detected power strength of the transmission between the source wireless device and the intermediate wireless device.

19. The wireless device of claim 17, wherein the instructions further comprise:

instructions to store the first data rate and the second data rate; and

instructions to store a time that the packet was received.

20. The wireless device of claim 19, wherein the instructions further comprise:

instructions to associate the time with information that identifies a media access card address of the source wireless device.

21. The wireless device of claim 19, wherein the instructions further comprise:

instructions to store a number of failed attempts of the intermediate wireless device to send the data to the destination wireless device.

22. A wireless system, comprising:

a source wireless device;

a destination wireless device; and

an intermediate wireless device, wherein the intermediate wireless device is configured to;

estimate, based at least on a transmission between the source wireless device and the intermediate wireless device, a first data rate for communicating with the source wireless device;

estimate, based at least on a transmission between the intermediate wireless device and the destination wireless device, a second data rate for communicating with the destination wireless device;

receive data sent from the source wireless device to the destination wireless device, the data including information identifying a third data rate for communicating between the source wireless device and the destination wireless device;

determine, based on the first data rate, the second data rate, and the third data rate, whether to send the data from the intermediate wireless device to the destination wireless device; and

send the data to the destination wireless device in response to determining to send the data to the destination wireless device.

23. The wireless system of claim 22, wherein the intermediate wireless device is configured to estimate the first data rate based on at least a detected power strength of the transmission between the source wireless device and the intermediate wireless device.