Coordination between multiple WLAN cores that are using the same frequency band

1. A method to communicate in a wireless local area network (WLAN) device having a first Media Access Control (MAC) and a second MAC, comprising:

determining whether transmission by the first MAC overlaps with reception by the second MAC using a same frequency band; and

relaxing a reception criteria by the second MAC when transmission by the first MAC overlaps with reception by the second MAC using the same frequency band and when an energy level of a channel received signal (CRS) is above a threshold energy level,

wherein the first MAC and the second MAC operate under a WLAN protocol.

2. The method of claim 1 , wherein relaxing the reception criteria includes:

receiving the CRS, wherein the CRS is associated with a clear to send (CTS) frame;

determining, in a first stage of the reception criteria, whether the energy level of the CRS is above the threshold energy level; and

assuming reception of the CTS frame when the energy level of the CRS is above the threshold energy level, even when other stages of the reception criteria are not satisfied.

3. The method of claim 1 , wherein relaxing the reception criteria includes:

receiving the CRS, wherein the CRS is associated with a clear to send (CTS) frame;

determining, in a first stage of the reception criteria, whether the energy level of the CRS is above the threshold energy level;

receiving a frame;

determining, in a second stage of the reception criteria, whether a matched filter correlation of a short training field (STF) in a synchronization (SYNC) word of the frame is above a minimum level of auto-correlation and has an expected periodicity when the energy level of the CRS is above the threshold energy level; and

assuming reception of the CTS frame if the matched filter correlation is above the minimum level and has the expected periodicity, even when other stages of the reception criteria are not satisfied.

4. The method of claim 1 , wherein relaxing the reception criteria includes:

receiving the CRS, wherein the CRS is associated with a clear to send (CTS) frame;

determining, in a first stage of the reception criteria, whether the energy level of the CRS is above the threshold energy level;

receiving a frame;

determining, in a second stage of the reception criteria, whether a first matched filter correlation of a short training field (STF) in a synchronization (SYNC) word of the frame is above a first minimum level of auto-correlation and has a first expected periodicity when the energy level of the CRS is above the threshold energy level;

determining, in a third stage of the reception criteria, whether a second matched filter correlation of a long training field (LTF) in the SYNC word of the frame is above a second minimum level of auto-correlation and has a second expected periodicity when the first matched filter correlation is above the first minimum level and has the first expected periodicity; and

assuming reception of the CTS frame if the second matched filter correlation is above the second minimum level and has the second expected periodicity, even when other stages of the reception criteria are not satisfied.

5. The method of claim 1 , wherein relaxing the reception criteria includes:

receiving the CRS, wherein the CRS is associated with a clear to send (CTS) frame;

determining, in a first stage of the reception criteria, whether the energy level of the CRS is above the threshold energy level;

receiving a frame;

determining, in a second stage of the reception criteria, whether a first matched filter correlation of a short training field (STF) in a synchronization (SYNC) word of the frame is above a first minimum level of auto-correlation and has a first expected periodicity when the energy level of CRS is above the threshold energy level;

determining, in a third stage of the reception criteria, whether a second matched filter correlation of a long training field (LTF) in the SYNC word of the frame is above a second minimum level of auto-correlation and has a second expected periodicity when the first matched filter correlation is above the first minimum level and has the first expected periodicity;

determining, in a fourth stage of the reception criteria, whether a Signal (SIG) field of the frame is successfully decoded when the second matched filter correlation is above the second minimum level and has the second expected periodicity; and

assuming reception of the CTS frame when the SIG field is successfully decoded, even when other stages of the reception criteria are not satisfied.

6. The method of claim 1 , wherein relaxing the reception criteria includes:

receiving the CRS, wherein the CRS is associated with a clear to send (CTS) frame;

determining, in a first stage of the reception criteria, whether the energy level of the CRS is above the threshold energy level;

receiving a frame;

determining, in a second stage of the reception criteria, whether a first matched filter correlation of a short training field (STF) in a synchronization (SYNC) word of the frame is above a first minimum level of auto-correlation and has a first expected periodicity when the energy level of the CRS is above the threshold energy level;

determining, in a third stage of the reception criteria, whether a second matched filter correlation of a long training field (LTF) in the SYNC word of the frame is above a second minimum level of auto-correlation and has a second expected periodicity when the first matched filter correlation is above the first minimum level and has the first expected periodicity;

determining, in a fourth stage of the reception criteria, whether a Signal (SIG) field of the frame is successfully decoded when the second matched filter correlation is above the second minimum level and has the second expected periodicity;

receiving a payload field of the frame;

determining, in a fifth stage of the reception criteria, whether an expected amount of data indicated by a length field of the SIG field has been received in the payload field; and

assuming reception of the CTS frame if the expected amount of data is received, even when other stages of the reception criteria are not satisfied.

7. The method of claim 1 , wherein relaxing the reception criteria includes:

receiving the CRS, wherein the CRS is associated with a clear to send (CTS) frame;

determining, in a first stage of the reception criteria, whether the energy level of the CRS is above the threshold energy level;

receiving a frame;

determining, in a second stage of the reception criteria, whether a first matched filter correlation of a short training field (STF) in a synchronization (SYNC) word of the frame is above a first minimum level of auto-correlation and has a first expected periodicity when the energy level of the CRS is above the threshold energy level;

determining, in a third stage of the reception criteria, whether a second matched filter correlation of a long training field (LTF) in the SYNC word of the frame is above a second minimum level of auto-correlation and has a second expected periodicity when the first matched filter correlation is above the first minimum level and has the first expected periodicity;

determining, in a fourth stage of the reception criteria, whether a Signal (SIG) field of the frame is successfully decoded when the second matched filter correlation is above the second minimum level and has the second expected periodicity;

receiving a payload field of the frame;

determining, in a fifth stage of the reception criteria, whether an expected amount of data as indicated by a length field of the SIG field has been received in the payload field;

determining, in a sixth stage of the reception criteria, whether a MAC address in a MAC header matches a MAC address of the second MAC when the expected amount of data has been received; and

assuming reception of the CTS frame when there is a match between the MAC address in the MAC header and the MAC address of the second MAC, even when other stages of the reception criteria are not satisfied.

8. A wireless local area network (WLAN) device, comprising:

a first Media Access Control (MAC); and

a second MAC coupled to the first MAC, wherein the first MAC and the second MAC operate under a WLAN protocol, and wherein the second MAC is configured to:

determine whether the first MAC and the second MAC are wirelessly communicating with external devices using a same frequency band,

determine whether transmission by the first MAC overlaps with reception by the second MAC, and

relax a reception criteria by the second MAC when transmission by the first MAC overlaps with reception by the second MAC and when an energy level of a channel received signal (CRS) is above a threshold energy level.

9. The WLAN device of claim 8 , wherein the second MAC is further configured to:

receive the CRS,

determine whether the energy level of the CRS is above the threshold energy level, and

assume reception of a clear to send (CTS) frame when the energy level of the CRS is above the threshold energy level.

10. The WLAN device of claim 8 , wherein the second MAC is further configured to:

receive the CRS,

determine whether the energy level of the CRS is above the threshold energy level,

receive a frame,

determine whether a matched filter correlation of a short training field (STF) in a synchronization (SYNC) word of the frame is above a minimum level of auto-correlation and has an expected periodicity when the energy level of the CRS is above the threshold energy level, and

assume reception of a clear to send (CTS) frame if the matched filter correlation is above the minimum level and has the expected periodicity.

11. The WLAN device of claim 8 , wherein the second MAC is further configured to:

receive the CRS,

determine whether the energy level of the CRS is above the threshold energy level,

receive a frame,

determine whether a first matched filter correlation of a short training field (STF) in a synchronization (SYNC) word of the frame is above a first minimum level of auto-correlation and has a first expected periodicity when the energy level of the CRS is above the threshold energy level,

determine whether a second matched filter correlation of a long training field (LTF) in the SYNC word of the frame is above a second minimum level of auto-correlation and has a second expected periodicity when the first matched filter correlation is above the first minimum level and has the first expected periodicity, and

assume reception of a clear to send (CTS) frame if the second matched filter correlation is above the second minimum level and has the second expected periodicity.

12. The WLAN device of claim 8 , wherein the second MAC is further configured to:

receive the CRS,

determine whether the energy level of the CRS is above the threshold energy level, receive a frame,

determine whether a first matched filter correlation of a short training field (STF) in a synchronization (SYNC) word of the frame is above a first minimum level of auto-correlation and has a first expected periodicity when the energy level of the CRS is above the threshold energy level,

determine whether a second matched filter correlation of a long training field (LTF) in the SYNC word of the frame is above a second minimum level of auto-correlation and has a second expected periodicity when the first matched filter correlation is above the first minimum level and has the first expected periodicity,

determine whether a Signal (SIG) field of the frame is successfully decoded when the second matched filter correlation is above the second minimum level and has the second expected periodicity; and

assume reception of a clear to send (CTS) frame when the SIG field is successfully decoded.

13. The WLAN device of claim 8 , wherein the second MAC is further configured to:

receive the CRS,

determine whether the energy level of the CRS is above the threshold energy level,

receive a frame,

determine whether a first matched filter correlation of a short training field (STF) in a synchronization (SYNC) word of the frame is above a first minimum level of auto-correlation and has a first expected periodicity when the energy level of the CRS is above the threshold energy level,

determine whether a second matched filter correlation of a long training field (LTF) in the SYNC word of the frame is above a second minimum level of auto-correlation and has a second expected periodicity when the first matched filter correlation is above the first minimum level and has the first expected periodicity,

determine whether a Signal (SIG) field of the frame is successfully decoded when the second matched filter correlation is above the second minimum level and has the second expected periodicity,

receive a payload field of the frame,

determine whether an expected amount of data as indicated by a length field of the SIG field has been received in the payload field,

determine whether a MAC address in a MAC header matches a MAC address of the second MAC when the expected amount of data has been received; and

assume reception of a clear to send (CTS) frame when there is a match between the MAC address in the MAC header and the MAC address of the second MAC.

14. A method to communicate in a wireless local area network (WLAN) device having a first Media Access Control (MAC) and a second MAC, comprising:

transmitting a first signal by the first MAC to the second MAC indicating a beginning of a first data transmission by the first MAC, wherein the first MAC and the second MAC operate under a WLAN protocol;

transmitting a second signal by the second MAC to the first MAC indicating a beginning of a second data transmission by the second MAC;

determining whether a block acknowledgement to be received by the first MAC will overlap with the second data transmission; and

padding the first data transmission to extend the first data transmission or curtailing the second data transmission only when the block acknowledgement to be received by the first MAC is expected to overlap with the second data transmission.

15. The method of claim 14 , further comprising:

determining a common duration of transmission for the first MAC and the second MAC.

16. The method of claim 14 , further comprising:

determining whether the first data transmission ends before the second data transmission based on a common duration of transmission, the first signal, and the second signal.

17. A wireless local area network (WLAN) device, comprising:

a first Media Access Control (MAC); and

a second MAC coupled to the first MAC, wherein the first MAC and the second MAC operate under a WLAN protocol;

wherein the first MAC is configured to transmit a first signal to the second MAC indicating beginning of a first data transmission by the first MAC and a duration of the first data transmission;

wherein the second MAC is configured to transmit a second signal to the first MAC to indicate beginning of a second data transmission by the second MAC; and

wherein the first MAC is configured to determine whether a block acknowledgement to be received by the first MAC will overlap with the second data transmission, and pad the first data transmission to extend the first data transmission only when the block acknowledgement to be received by the first MAC is expected to overlap with the second data transmission.

18. The WLAN device of claim 17 , wherein the second MAC is further configured to determine a common duration of transmission for the first MAC and the second MAC and transmit the common duration to the first MAC.

19. The WLAN device of claim 17 , wherein the first MAC is further configured to determine a common duration of transmission based on a desired duration of transmission of the first MAC and the second MAC.

20. The WLAN device of claim 17 , wherein the first MAC is further configured to determine whether the first data transmission ends before the second data transmission based on a common duration of transmission and the second signal.