Methods and apparatus for carrying out backoff operations

1. A method, comprising:

determining, at a communication device, that a wireless communication channel is idle;

in response to determining that the wireless communication channel is idle, decrementing a backoff counter of the communication device;

detecting, at the communication device, reception of a physical layer protocol data unit (PPDU);

during reception of a beginning portion of the PPDU, comparing, at the communication device, an energy level associated with the PPDU to a first threshold;

in response to determining that the energy level associated with the PPDU exceeds the first threshold, pausing, at the communication device, the backoff counter;

determining, at the communication device, whether to compare, after pausing the backoff counter, the energy level associated with a remaining portion of the PPDU to a second threshold that is higher than the first threshold, including determining that the energy level associated with the remaining portion of the PPDU should be compared to the first threshold when a physical layer (PHY) preamble of the PPDU includes a basic service set (BSS) color field set to a value reserved for inter-BSS communications and communications with unassociated client stations;

in response to determining that the energy level associated with the remaining portion of the PPDU is to be compared to the first threshold:

decrementing, at the communication device, the backoff counter when the energy level associated with the PPDU does not exceed the first threshold, and

pausing, at the communication device, the backoff counter when the energy level associated with the PPDU exceeds the first threshold; and

in response to determining that the energy level associated with the remaining portion of the PPDU is to be compared to the second threshold:

decrementing, at the communication device, the backoff counter when the energy level associated with the PPDU does not exceed the second threshold, and

pausing, at the communication device, the backoff counter when the energy level associated with the PPDU exceeds the second threshold.

2. The method of claim 1 , wherein determining whether to compare, after pausing the backoff counter, the energy level associated with a remaining portion of the PPDU to the second threshold further includes:

determining whether any media access control (MAC) addresses included in a MAC layer header of the PPDU corresponds to an access point (AP) with which the communication device is associated.

3. The method of claim 2 , wherein determining whether to compare, after pausing the backoff counter, the energy level associated with a remaining portion of the PPDU to the second threshold further includes:

determining that the energy level associated with the remaining portion of the PPDU should be compared to the first threshold when one of the MAC addresses in the MAC layer header of the PPDU corresponds to the AP with which the communication device is associated.

4. The method of claim 1 , wherein:

the PPDU includes a duration field in a media access control (MAC) layer header of the PPDU; and

the method further comprises: when i) the PPDU corresponds to the BSS with which the communication device is associated and ii) the communication device is not a transmission opportunity (TXOP) responder, setting a network allocation vector (NAV) timer according to the duration field if a value in the duration field is larger than a value of the NAV timer.

5. The method of claim 1 , wherein:

comparing, during reception of the beginning portion of the PPDU, the energy level associated with the PPDU to the first threshold is performed by a physical layer (PHY) processor of the communication device;

the method further comprises: signaling, by the PHY processor to a media access control (MAC) processor of the communication device, whether the energy level associated with the PPDU exceeds the first threshold;

pausing the backoff counter is performed by the MAC processor in response to the PHY processor signaling that the energy level associated with the PPDU exceeds the first threshold.

6. The method of claim 5 , further comprising, in response to determining that the energy level associated with the remaining portion of the PPDU is to be compared to the first threshold:

comparing, by the PHY processor, the energy level associated with the PPDU to the first threshold;

signaling, by the PHY processor to the MAC processor, whether the energy level associated with the PPDU exceeds the first threshold;

wherein decrementing the backoff counter when the energy level associated with the PPDU does not exceed the first threshold is performed by the MAC processor; and

wherein pausing the backoff counter when the energy level associated with the PPDU exceeds the first threshold is performed by the MAC processor.

7. The method of claim 6 , further comprising, in response to determining that the energy level associated with the remaining portion of the PPDU is to be compared to the second threshold:

comparing, by the PHY processor, the energy level associated with the PPDU to the second threshold; and

signaling, by the PHY processor to the MAC processor, whether the energy level associated with the PPDU exceeds the second threshold;

wherein decrementing the backoff counter when the energy level associated with the PPDU does not exceed the second threshold is performed by the MAC processor; and

wherein pausing the backoff counter when the energy level associated with the PPDU exceeds the second threshold is performed by the MAC processor.

8. An apparatus, comprising:

a wireless network interface device associated with a communication device, wherein the wireless network interface device includes one or more integrated circuit (IC) devices configured to:

determine that a wireless communication channel is idle,

in response to determining that the wireless communication channel is idle, decrement a backoff counter,

detect reception of a physical layer protocol data unit (PPDU),

during reception of a beginning portion of the PPDU, compare an energy level associated with the PPDU to a first threshold,

in response to determining that the energy level associated with the PPDU exceeds the first threshold, pause the backoff counter, and

determine whether to compare, after pausing the backoff counter, the energy level associated with a remaining portion of the PPDU to a second threshold that is higher than the first threshold, including determining that the energy level associated with the remaining portion of the PPDU should be compared to the first threshold when a physical layer (PHY) preamble of the PPDU includes a basic service set (BSS) color field set to a value reserved for inter-BSS communications and communications with unassociated client stations;

wherein the one or more IC devices are further configured to, in response to determining that the energy level associated with the remaining portion of the PPDU is to be compared to the first threshold:

decrement the backoff counter when the energy level associated with the PPDU does not exceed the first threshold, and

pause the backoff counter when the energy level associated with the PPDU exceeds the first threshold; and

wherein the one or more IC devices are further configured to, in response to determining that the energy level associated with the remaining portion of the PPDU is to be compared to the second threshold:

decrement the backoff counter when the energy level associated with the PPDU does not exceed the second threshold, and

pause the backoff counter when the energy level associated with the PPDU exceeds the second threshold.

9. The apparatus of claim 8 , wherein the one or more IC devices are further configured to:

determine whether any media access control (MAC) addresses included in a MAC layer header of the PPDU corresponds to an access point (AP) with which the communication device is associated as part of determining whether to compare, after pausing the backoff counter, the energy level associated with a remaining portion of the PPDU to the second threshold.

10. The apparatus of claim 9 , wherein the one or more IC devices are further configured to:

determine that the energy level associated with the remaining portion of the PPDU should be compared to the first threshold when one of the MAC addresses in the MAC layer header of the PPDU corresponds to the AP with which the communication device is associated.

11. The apparatus of claim 8 , wherein:

the PPDU includes a duration field in a media access control (MAC) layer header of the PPDU; and

the one or more IC devices are further configured to: when i) the PPDU corresponds to the BSS with which the communication device is associated and ii) the communication device is not a transmission opportunity (TXOP) responder, set a network allocation vector (NAV) timer according to the duration field if a value in the duration field is larger than a value of the NAV timer.

12. The apparatus of claim 8 , wherein:

the wireless network interface device includes:

a physical layer (PHY) processor implemented on the one or more IC devices, and

a media access control (MAC) processor coupled to the PHY processor;

the MAC processor is implemented on the one or more IC devices;

the PHY processor is configured to:

compare, during reception of the beginning portion of the PPDU, the energy level associated with the PPDU to the first threshold, and

signal, to the MAC processor, whether the energy level associated with the PPDU exceeds the first threshold; and

the MAC processor is configured to: pause the backoff counter in response to the PHY processor signaling that the energy level associated with the PPDU exceeds the first threshold.

13. The apparatus of claim 12 , wherein:

the PHY processor is configured to, in response to determining that the energy level associated with the remaining portion of the PPDU is to be compared to the first threshold:

compare the energy level associated with the PPDU to the first threshold, and

signal, to the MAC processor, whether the energy level associated with the PPDU exceeds the first threshold; and

the MAC processor is configured to, in response to determining that the energy level associated with the remaining portion of the PPDU is to be compared to the first threshold:

decrement the backoff counter when the PHY processor signals that the energy level associated with the PPDU does not exceed the first threshold, and

pause the backoff counter when the PHY processor signals that the energy level associated with the PPDU exceeds the first threshold.

14. The apparatus of claim 13 , wherein:

the PHY processor is configured to, in response to determining that the energy level associated with the remaining portion of the PPDU is to be compared to the second threshold:

compare the energy level associated with the PPDU to the second threshold, and

signal, to the MAC processor, whether the energy level associated with the PPDU exceeds the second threshold;

the MAC processor is configured to, in response to determining that the energy level associated with the remaining portion of the PPDU is to be compared to the second threshold:

decrement the backoff counter when the PHY processor signals that the energy level associated with the PPDU does not exceed the second threshold, and

pause the backoff counter when the PHY processor signals that the energy level associated with the PPDU exceeds the second threshold.

15. The apparatus of claim 12 , wherein: the PHY processor comprises one or more transceivers.

16. The apparatus of claim 15 , further comprising: one or more antennas coupled to the one or more transceivers.

17. The apparatus of claim 16 , further comprising: a host processor coupled to the network interface device.