METHODS AND APPARATUS FOR CLEAR CHANNEL ASSESSMENT

• US 20140355556A1
• Filed: 05/29/2014
• Published: 12/04/2014
• Est. Priority Date: 06/03/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Vermani, Sameer, Merlin, Simone, Baik, Eugene Jong-Hyon, Tian, Bin, Yucek, Tevfik
• Granted Patent: US 9,521,557 B2
• Time in Patent Office: Days
• US Class Current: 370/330
• CPC Class Codes: H04L 27/0006 Assessment of spectral gaps suitable for allocating digitally modulated signals, e.g. for carrier allocation in cognitive radio for spectrum sharing between different networks H04W16/14
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 74/0816 with collision avoidance

Abstract

One aspect disclosed is a method in a wireless communications system including a first primary channel having a first frequency spectrum bandwidth and a second primary channel having a second frequency spectrum bandwidth, wherein the second frequency spectrum bandwidth includes the first frequency spectrum bandwidth. The method includes performing a first and a second back-off procedure at least partially in parallel, the first back-off procedure based on whether the first primary channel is idle, and the second back-off procedure based on whether the second primary channel is idle, and transmitting a wireless message based on whether the first or the second back-off procedure completes first.

Claims

1. A method in a wireless communications system including a first primary channel having a first frequency spectrum bandwidth and a second primary channel having a second frequency spectrum bandwidth, wherein the second frequency spectrum bandwidth includes the first frequency spectrum bandwidth, comprising:

performing a first and a second back-off procedure at least partially in parallel, the first back-off procedure based on whether the first primary channel is idle, and the second back-off procedure based on whether the second primary channel is idle; and

transmitting a wireless message based on whether the first or the second back-off procedure completes first.

2. The method of claim 1, further comprising determining whether one or more secondary channels are idle for a PCF Inter-frame Space (PIFS) time period before the transmission of the wireless message, wherein the transmitting of the wireless message is further based on the determining.

3. The method of claim 2 further comprising transmitting the wireless message without utilizing a secondary channel if an amount of data waiting for transmission is below a data size threshold.

4. The method of claim 2, wherein the one or more secondary channels comprise a two megahertz channel, a four megahertz channel, and an eight megahertz channel.

5. The method of claim 3, further comprising transmitting the wireless message on a secondary channel if the secondary channel is idle PCF Inter-frame Space (PIFS) time before the transmission and the amount of data waiting for transmission is above the data size threshold.

6. The method of claim 1, further comprising determining whether the first primary channel is idle, wherein the determining comprises:

determining whether a preamble has been detected on the first primary channel during a first period of time; and

determining whether a guard interval has been detected on the first primary channel during a second period of time.

7. The method of claim 1, further comprising transmitting the wireless message on the first primary channel if the first back-off procedure completes before the second back-off procedure.

8. The method of claim 7, further comprising transmitting the wireless message on the second primary channel if the second back-off procedure completes first.

9. The method of claim 1, wherein determining whether the second primary channel is idle comprises:

determining whether a first preamble has been detected on the second primary channel during a first threshold period of time;

determining whether a second preamble has been detected on the first primary channel during a second threshold period of time;

determining whether a guard interval has been detected on the second primary channel during a third threshold period of time; and

determining whether the second primary channel is idle based at least in part on detection of the first preamble, the second preamble and the guard interval.

10. An apparatus in a wireless communications system including a first primary channel having a first frequency spectrum bandwidth and a second primary channel having a second frequency spectrum bandwidth, wherein the second frequency spectrum bandwidth includes the first frequency spectrum bandwidth, comprising:

a processor configured to;

perform a first back-off procedure at least partially in parallel, the first back-off procedure based on whether the first primary channel is idle, and

the second back-off procedure based on whether the second primary channel is idle; and

a transmitter configured to transmit a wireless message based on whether the first or second back-off procedure completes first.

11. The apparatus of claim 10,

wherein the processor is further configured to determine whether one or more secondary channels are idle for a PCF Inter-frame Space (PIFS) time period before the transmission of the wireless message, and

wherein the transmitter is further configured to transmit the wireless message is further based on the determining.

12. The apparatus of claim 11, wherein the transmitter is further configured to not utilize a secondary channel for transmission of the wireless message if an amount of data waiting for transmission is below a data size threshold.

13. The apparatus of claim 11, wherein the one or more secondary channels comprise a two megahertz channel, a four megahertz channel, and an eight megahertz channel.

14. The apparatus of claim 12, wherein the transmitter is configured to transmit the wireless message on a secondary channel if the secondary channel is idle PCF Inter-frame Space (PIFS) time before the transmission and the amount of data waiting for transmission is above the data size threshold.

15. The apparatus of claim 10, wherein the processor is configured to determine whether the first primary channel is idle by:

determining whether a preamble has been detected on the first primary channel during a first period of time;

determining whether a guard interval has been detected on the first primary channel during a second period of time; and

determining whether the first primary channel is idle based at least in part on detection of the preamble and the guard interval.

16. The apparatus of claim 10, wherein the transmitter is configured to transmit the wireless message on the first primary channel when the first back-off procedure completes before the second back-off procedure.

17. The apparatus of claim 16, wherein the transmitter is configured to transmit the wireless message on the second primary channel when the second back-off procedure completes before the first back-off procedure.

18. The apparatus of claim 10, wherein the processor is configured to determine whether the second primary channel is idle by:

determining whether a first preamble has been detected on the second primary channel during a first threshold period of time;

determining whether a second preamble has been detected on the first primary channel during a second threshold period of time;

determining whether a guard interval has been detected on the second primary channel during a third threshold period of time; and

determining whether the second primary channel is idle based at least in part on detection of the first preamble, the second preamble and the guard interval.

19. An apparatus in a wireless communications system including a first primary channel having a first frequency spectrum bandwidth and a second primary channel having a second frequency spectrum bandwidth, wherein the second frequency spectrum bandwidth includes the first frequency spectrum bandwidth, comprising:

means for performing a first and second back-off procedure at least partially in parallel, the first back-off procedure based on whether the first primary channel is idle, and the second back-off procedure based on whether the second primary channel is idle; and

means for transmitting a wireless message based on whether the first or second back-off procedure completes first.

20. The apparatus of claim 19, further comprising means for determining whether one or more secondary channels are idle for a PCF Inter-frame Space (PIFS) time period before the means for transmitting transmits the wireless message, wherein the means for transmitting the wireless message is configured to transmit the message based on whether the one or more secondary channels are idle for a PCF Inter-frame Space (PIFS) time period before transmission of the wireless message.

21. The apparatus of claim 20, wherein the means for transmitting is configured to utilize a secondary channel if an amount of data waiting for transmission is below a data size threshold.

22. The apparatus of claim 20, wherein the one or more secondary channels comprise a two megahertz channel, a four megahertz channel, and an eight megahertz channel.

23. The apparatus of claim 19, wherein the means for determining is configured to determine whether the first primary channel is idle by:

determining whether a preamble has been detected on the first primary channel during a first period of time;

determining whether a guard interval has been detected on the first primary channel during a second period of time; and

determining whether the first primary channel is idle based at least in part on detection of the preamble and the guard interval.

24. The apparatus of claim 19, wherein the means for transmitting the wireless message is configured to transmit the wireless message on the first primary channel if the first back-off procedure completes before the second back-off procedure.

25. The apparatus of claim 24, wherein means for transmitting the wireless message is configured to transmit the message on the second primary channel when the second back-off procedure completes before the first back-off procedure.

26. The apparatus of claim 19, wherein the means for performing the first and second back-off procedure is configured to determine whether the second primary channel is idle by:

determining whether a first preamble has been detected on the second primary channel during a first threshold period of time;

determining whether a second preamble has been detected on the first primary channel during a second threshold period of time;

determining whether a guard interval has been detected on the second primary channel during a third threshold period of time; and

determining whether the second primary channel is idle based at least in part on detection of the first preamble, the second preamble and the guard interval.

27. A computer readable storage medium comprising instructions that when executed cause one or more processors to perform a method in a wireless communications system including a first primary channel having a first frequency spectrum bandwidth and a second primary channel having a second frequency spectrum bandwidth, wherein the second frequency spectrum bandwidth includes the first frequency spectrum bandwidth, the method comprising:

performing a first and second back-off procedure at least partially in parallel, the first back-off procedure based on whether the first primary channel is idle, and the second back-off procedure based on whether the second primary channel is idle; and

transmitting a wireless message based on whether the first or second back-off procedure completes first.

28. A method in a wireless communications system including a first primary channel having a first frequency spectrum bandwidth and a second primary channel having a second frequency spectrum bandwidth, wherein the second frequency spectrum bandwidth includes the first frequency spectrum bandwidth, comprising:

performing a first back-off procedure based on whether the first primary channel is idle if a transmission bandwidth for a wireless message is the first frequency spectrum bandwidth;

performing a second back-off procedure based on whether the second primary channel is idle if the transmission bandwidth for the wireless message is greater than the first frequency spectrum bandwidth;

transmitting the wireless message based on a completion of the first back-off procedure if the transmission bandwidth is the first frequency spectrum bandwidth; and

transmitting the wireless message based on a completion of the second back-off procedure if the transmission bandwidth is greater than the first frequency spectrum bandwidth.

29. The method of claim 28, further comprising updating the transmission bandwidth based on whether one or more secondary channels are idle for a PCF Inter-frame Space (PIFS) time period before the wireless message is transmitted if the transmission bandwidth is greater than the first frequency spectrum bandwidth.

30. The method of claim 29, wherein the updating of the transmission bandwidth is further based on whether an amount of data waiting for transmission is above a threshold.

31. The method of claim 29, wherein the one or more secondary channels comprise a two megahertz secondary channel, a four megahertz secondary channel, and an eight megahertz secondary channel.

32. The method of claim 31, further comprising determining to transmit the wireless message on the second primary channel if the amount of data available for transmission is below the threshold or if no secondary channels are idle for the PCF Inter-frame space (PIFS) time period when the second back-off procedure is complete.

33. An apparatus in a wireless communications system including a first primary channel having a first frequency spectrum bandwidth and a second primary channel having a second frequency spectrum bandwidth, wherein the second frequency spectrum bandwidth includes the first frequency spectrum bandwidth, comprising:

a processor configured to;

perform a first back-off procedure based on whether the first primary channel is idle if a transmission bandwidth for a wireless message is the first frequency spectrum bandwidth, and

perform a second back-off procedure based on whether the second primary channel is idle if the transmission bandwidth for the wireless message is greater than the first frequency spectrum bandwidth;

a transmitter configured to;

transmit the wireless message based on a completion of the first back-off procedure if the transmission bandwidth is the first frequency spectrum bandwidth, and

transmit the wireless message based on a completion of the second back-off procedure if the transmission bandwidth is greater than the first frequency spectrum bandwidth.

34. The apparatus of claim 33, wherein the processor is further configured to update the transmission bandwidth based on whether one or more secondary channels are idle for a PCF Inter-frame Space (PIFS) time period before the wireless message is transmitted if the transmission bandwidth is greater than the first frequency spectrum bandwidth.

35. The apparatus of claim 34, wherein the processor is further configured to update the transmission bandwidth based on whether an amount of data waiting for transmission is above a threshold.

36. The apparatus of claim 34, wherein the one or more secondary channels comprise a two megahertz secondary channel, a four megahertz secondary channel, and an eight megahertz secondary channel.

37. The apparatus of claim 35, wherein the transmitter is configured to transmit the wireless message on the second primary channel if the amount of data waiting for transmission is below the threshold or no secondary channels are idle for the PCF Inter-frame space (PIFS) time period when the second back-off procedure is complete.

38. An apparatus in a wireless communications system including a first primary channel having a first frequency spectrum bandwidth and a second primary channel having a second frequency spectrum bandwidth, wherein the second frequency spectrum bandwidth includes the first frequency spectrum bandwidth, comprising:

means for performing a first back-off procedure based on whether the first primary channel is idle if a transmission bandwidth for a wireless message is the first frequency spectrum bandwidth;

means for performing a second back-off procedure based on whether the second primary channel is idle if the transmission bandwidth for the wireless message is greater than the first frequency spectrum bandwidth;

means for transmitting the wireless message based on a completion of the first back-off procedure if the transmission bandwidth is the first frequency spectrum bandwidth; and

means for transmitting the wireless message based on a completion of the second back-off procedure if the transmission bandwidth is greater than the first frequency spectrum bandwidth.

39. The apparatus of claim 38, further comprising means for updating the transmission bandwidth based on whether one or more secondary channels are idle for a PCF Inter-frame Space (PIFS) time period before the wireless message is transmitted if the transmission bandwidth is greater than the first frequency spectrum bandwidth.

40. The apparatus of claim 39, wherein the means for updating is further configured to update the transmission bandwidth based on whether an amount of data waiting for transmission is above a threshold.

41. The apparatus of claim 39, wherein the one or more secondary channels comprise a two megahertz secondary channel, a four megahertz secondary channel, and an eight megahertz secondary channel.

42. The apparatus of claim 40, wherein the means for transmitting is configured to transmit the wireless message on the second primary channel if the amount of data waiting for transmission is below the threshold or no secondary channels are idle for the PCF Inter-frame space (PIFS) time period when the second back-off procedure is complete.

43. A computer readable storage medium comprising instructions that when executed cause a processor to perform a method in a wireless communications system including a first primary channel having a first frequency spectrum bandwidth and a second primary channel having a second frequency spectrum bandwidth, wherein the second frequency spectrum bandwidth includes the first frequency spectrum bandwidth, the method comprising:

performing a first back-off procedure based on whether the first primary channel is idle if a transmission bandwidth for a wireless message is the first frequency spectrum bandwidth.

performing a second back-off procedure based on whether the second primary channel is idle if the transmission bandwidth for the wireless message is greater than the first frequency spectrum bandwidth;

transmitting the wireless message based on a completion of the first back-off procedure if the transmission bandwidth is the first frequency spectrum bandwidth; and

transmitting the wireless message based on a completion of the second back-off procedure if the transmission bandwidth is greater than the first frequency spectrum bandwidth.

44. The computer readable storage medium of claim 43, the method further comprising updating the transmission bandwidth based on whether one or more secondary channels are idle for a PCF Inter-frame Space (PIFS) time period before the wireless message is transmitted if the transmission bandwidth is greater than the first frequency spectrum bandwidth.

45. The computer readable storage medium of claim 44, wherein the updating of the transmission bandwidth is further based on whether an amount of data waiting for transmission is above a threshold.

46. The computer readable storage medium of claim 44, wherein the one or more secondary channels comprise a two megahertz secondary channel, a four megahertz secondary channel, and an eight megahertz secondary channel.

47. The computer readable storage medium of claim 45, the method further comprising determining to transmit the wireless message on the second primary channel if the amount of data is below the threshold or no secondary channels are idle for the PCF Inter-frame space (PIFS) time period when the second back-off procedure is complete.