Methods and apparatus for clear channel assessment

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

• a hardware processor configured to:
• perform a first and a second back-off procedure at least partially in parallel, each of the first and second back-off procedures conditionally update separate counters over individual periods of time when the first or second primary channels are idle respectively, conditionally reset the separate counters over the individual periods of time when the first or second primary channels are busy respectively, wherein the first and second back-off procedures are each complete when their respective counters reach a respective predetermined threshold value, wherein the second primary channel is not idle when the first primary channel is not idle;
• and
• a transmitter configured to transmit a wireless message over the first primary channel in response to the first back-off procedure completing before the second back-off procedure;
• and transmit the wireless message over the second primary channel in response to the second back-off procedure completing before the first back-off procedure.

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

• means for performing a first and a second back-off procedure at least partially in parallel, each of the first and second back-off procedures conditionally update separate counters over individual periods of time when the first or second primary channels are idle respectively, conditionally reset the separate counters over the individual periods of time when the first or second primary channels are busy respectively, wherein the first and second back-off procedures are each complete when their respective counters reach a respective predetermined threshold value, wherein the second primary channel is not idle when the first primary channel is not idle;
• means for transmitting a wireless message over the first primary channel in response to the first back-off procedure completing before the second back-off procedure;
• and
• means for transmitting the wireless message over the second primary channel in response to the second back-off procedure completing before the first back-off procedure.

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

• performing, by a wireless device, a first and a second back-off procedure at least partially in parallel, each of the first and second back-off procedures conditionally update separate counters over individual periods of time when the first or second primary channels are idle respectively, conditionally reset the separate counters over the individual periods of time when the first or second primary channels are busy respectively, wherein the first and second back-off procedures are each complete when their respective counters reach a respective predetermined threshold value, wherein the second primary channel is not idle when the first primary channel is not idle;
• transmitting a wireless message over the first primary channel in response to the first back-off procedure completing before the second back-off procedure;
• and
• transmitting the wireless message over the second primary channel in response to the second back-off procedure completing before the first back-off procedure.