MULTI-HOP WIRELESS MESH NETWORK MEDIUM ACCESS CONTROL PROTOCOL

• US 20070147322A1
• Filed: 10/11/2006
• Published: 06/28/2007
• Est. Priority Date: 10/19/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Agrawal, Avneesh, Julian, David, Jain, Nikhil
• Granted Patent: US 8,576,872 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: H04W 74/0816 with collision avoidance
• CPC Class Codes: H04W 80/00 Wireless network protocols or protocol adaptations to wireless operation
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

Systems and methodologies are described that facilitate mitigating a hidden node condition in a wireless mesh network wherein nodes utilize a request-to-send/clear-to-send (RTS/CTS) protocol in conjunction with an asynchronous hybrid automatic repeat request protocol. For instance, a node may contend for a set of subcarriers by sending an RTS signal over the desired subcarriers, and may receive a CTS signal over the contended subcarriers, wherein the CTS signal indicates which subcarriers the node may transmit data over. If another node has won the contention for a particular subcarrier, requesting node may adjust a power level at which it transmits an RTS or a data packet in order to permit the requesting node to utilize the subcarrier without interfering with the winning node.

Claims

1. A method of multi-carrier wireless transmission, comprising:

contending for a set of subcarriers independent of contending for other subcarriers; and

determining whether a subset of the set of contended subcarriers is available for data transmission.

2. The method of claim 1, further comprising transmitting a request to send (RTS) signal for the set of contended subcarriers.

3. The method of claim 2, further comprising transmitting a preference list of subcarriers.

4. The method of claim 2, further comprising receiving a clear-to-send (CTS) signal for a subset of the set of contended subcarriers, wherein the CTS signal has been transmitted at a known power spectral density (PSD).

5. The method of claim 4, further comprising transmitting a data signal utilizing the subset of contended subcarriers.

6. The method of claim 5, further comprising transmitting the data signal utilizing less than total available bandwidth associated with the subset of contended subcarriers.

7. The method of claim 1, further comprising employing an asynchronous HARQ protocol to perform rate prediction.

8. The method of claim 1, wherein the subset of the set of contended subcarriers comprises the entire set of contended subcarriers.

9. The method of claim 4, further comprising transmitting the RTS signal at a predefined PSD, and receiving the CTS signal over the set of contended subcarriers.

10. The method of claim 9, further comprising transmitting the data signal at a lower PSD than the predefined PSD.

11. The method of claim 4, further comprising transmitting the RTS and data signals at a lower PSD than the predefined PSD.

12. The method of claim 4, further comprising utilizing the CTS signal as a pilot for an open loop channel gain estimate.

13. The method of claim 4, further comprising employing a multi-valued CTS signal, wherein a CTS value is based on an interference level associated with a recent RTS signal.

14. The method of claim 13, further comprising selecting a transmission power level for the RTS signal and the data signal as a function of a CTS value for one or more interfering nodes.

15. An apparatus that facilitates multi-carrier wireless transmission, comprising:

a contending module configured to contend for one or more subcarriers independently of other subcarriers; and

a determining module configured to determine whether a subset of the contended subcarriers are available.

16. The apparatus of claim 15, further comprising a transmitter that sends a request-to-send (RTS) signal for the one or more contended subcarriers.

17. The apparatus of claim 16, further comprising a receiver that receives a clear-to-send (CTS) signal for a subset of the one or more contended subcarriers.

18. The apparatus of claim 17, wherein the transmitter transmits a data signal utilizing the subset of the one or more contended subcarriers.

19. The apparatus of claim 18, wherein the transmitter transmits the data signal over less than all available bandwidth associated with the one or more contended subcarriers.

20. The apparatus of claim 17, further comprising a processor that performs rate prediction using an asynchronous HARQ protocol.

21. The apparatus of claim 17, wherein the subset of the one or more contended subcarriers comprises all of the one or more contended subcarriers.

22. The apparatus of claim 17, wherein the transmitter sends the RTS signal at a predetermined PSD, and the receiver receives the CTS signal, over the one or more contended subcarriers.

23. The apparatus of claim 22, wherein the transmitter transmits the data signal at a PSD that is lower than the predetermined PSD.

24. The apparatus of claim 17, wherein the receiver receives the CTS signal over the one or more contended subcarriers, the CTS having been transmitted at a predetermined PSD.

25. The apparatus of claim 24, wherein the transmitter sends the RTS and data signals at a PSD below the predetermined PSD.

26. The apparatus of claim 20, wherein the processor employs the CTS signal as a pilot for an open loop channel gain estimate.

27. The apparatus of claim 17, wherein the receiver receives a multi-valued CTS signal, wherein a CTS value indicates an interference level associated with a recent RTS signal.

28. The apparatus of claim 15, wherein the apparatus is employed in an access terminal.

29. The apparatus of claim 15, wherein the apparatus is employed in an access point.

30. The apparatus of claim 16, wherein the transmitter transmits a preference list of subcarriers.

31. An apparatus that facilitates performing multi-carrier wireless transmission, comprising:

means for contending for a set of subcarriers independently of other subcarriers;

means for determining whether a subset of the contended set of subcarriers is available for data transmission.

32. The apparatus of claim 31, further comprising means for transmitting a request to send (RTS) signal for the contended set of subcarriers within a portion of available bandwidth, which is less than the total bandwidth utilized for multiple access.

33. The apparatus of claim 32, further comprising means for receiving a clear-to-send (CTS) signal for the contended set of subcarriers, wherein the means for transmitting sends a data packet over the contended set of subcarriers.

34. The apparatus of claim 32, wherein the means for transmitting sends the data packet over less than all available bandwidth associated with the contended set of subcarriers.

35. The apparatus of claim 31, further comprising means for performing rate prediction using an asynchronous HARQ protocol.

36. The apparatus of claim 32, wherein the means for transmitting sends the RTS signal at a known PSD, and the means for receiving receives the CTS signal, over the contended set of subcarriers.

37. The apparatus of claim 36, wherein the means for transmitting transmits the data signal at a PSD that is lower than the known PSD.

38. The apparatus of claim 33, wherein the means for receiving receives the CTS signal, which was transmitted at the known PSD, over the contended set of subcarriers.

39. The apparatus of claim 38, wherein the means for transmitting sends the RTS and data signals at less than the known PSD.

40. The apparatus of claim 33, further comprising means for utilizing the CTS signal as a pilot for an open loop channel gain estimate.

41. The apparatus of claim 33, wherein the means for receiving receives a multi-valued CTS signal, wherein a CTS value indicates an interference level associated with a recent RTS signal.

42. The apparatus of claim 31, wherein the apparatus is employed in an access terminal.

43. The apparatus of claim 31, wherein the apparatus is employed in an access point.

44. The apparatus of claim 32, wherein the means for transmitting transmits a preference list of subcarriers.

45. A machine-readable medium comprising instructions for facilitating multi-carrier wireless transmission, wherein the instructions upon execution cause a machine to:

contend for a set of subcarriers independent of contending for other subcarriers; and

determine whether a subset of the set of contended subcarriers is available for data transmission.

46. A processor for facilitating multi-carrier wireless transmission, the processor being configured to:

contend for one or more subcarriers independent of contending for other subcarriers; and

determine whether a subset of the one or more contended subcarriers is available for data transmission.