Mitigating interference between co-located wireless technologies
An apparatus has a first communication module that is compatible with a first wireless communication technology, and a second communication module that is compatible with a second, different, wireless communication technology. Transmissions by each communication module may contribute to interference at the other communication module. In one example, a Block Acknowledgement Request is transmitted by the apparatus during a downlink period of the second communication module so that the Block Acknowledgement transmitted in response is received during the downlink period. In another example, the apparatus calculates a maximum size of A-MPDU to receive and notifies an access point of that maximum size. In a further example, the apparatus, having notified an access point of operation in a power save mode, polls the access point for buffered frames at the start of a downlink period of the second communication module.
1. A method for co-existence in an apparatus having a wireless local area network (WLAN) communication module operative for communication with an access point (AP) in a WLAN frequency band, and a Long Term Evolution (LTE) communication module served by an evolved base node (eNB) and operative in one or more LTE Time Division Duplex (TDD) frequency bands that are adjacent or near the WLAN frequency band, the method comprising:
determining, from a current LTE TDD frame configuration of the LTE communication module, a duration of a downlink period reserved by the eNB for downlink communications;
calculating, using the determined duration of the downlink period and an estimated data rate between the WLAN communication module and the AP, a maximum receivable size of any aggregated medium access control (MAC) protocol data unit (A-MPDU) receivable by the WLAN communication module from the AP that ensures that A-MPDU reception is fully containable within the downlink period;
notifying the AP of the calculated maximum receivable size of any A-MPDU and receiving from the AP an A-MPDU having a size that does not exceed the calculated maximum receivable size of any A-MPDU.
2. The method of claim 1 , further comprising:
calculating the maximum receivable size of any A-MPDU as a function of an estimated overhead applicable to A-MPDU transmissions caused by a physical layer of the AP.
3. The method of claim 1 , further comprising:
calculating the maximum receivable size of any A-MPDU as a function of an estimated contention window required by the AP to access a wireless medium when transmitting any A-MPDU to the apparatus.
4. An apparatus comprising:
a host processor;
a wireless local area network (WLAN) communication module coupled to the host processor, the WLAN communication module operative for communications in a WLAN frequency band with an access point (AP); and
a Long Term Evolution (LTE) communication module coupled to the host processor, the LTE communication module operative in one or more LTE Time Division Duplex (TDD) frequency bands that are adjacent or near the WLAN frequency band,
wherein the WLAN communication module is operative:
to determine, from a current LTE TDD frame configuration of the LTE communication module, a duration of a downlink period reserved by the eNB for downlink communications;
to calculate, using the determined duration of the downlink period and an estimated data rate between the WLAN communication module and the AP, a maximum receivable size of any aggregated medium access control (MAC) protocol data unit (A-MPDU) receivable by the WLAN communication module from the AP that ensures that A-MPDU reception is fully containable within the downlink period;
to notify the AP of the calculated maximum receivable size of any A-MPDU and to receive from the AP an A-MPDU having a size that does not exceed the maximum receivable size of any A-MPDU.
5. The apparatus of claim 4 , wherein the WLAN communication module is operative to calculate the maximum receivable size of any A-MPDU as a function of an estimated overhead applicable to A-MPDU transmissions caused by a physical layer of the AP.
6. The method of claim 1 , wherein the A-MPDU is received from the AP:
responsive to transmitting a PS-Poll frame to the AP at the start of the downlink period.
7. The method of claim 1 , further comprising, responsive to determining a change in the estimated data rate to a new estimated data rate:
re-calculating the maximum receivable size of any A-MPDU using the new estimated data rate; and
notifying the AP of the re-calculated maximum receivable size of any A-MPDU.
8. The method of claim 7 , wherein the change in the estimated data rate exceeds a threshold value.
9. The method of claim 1 , wherein the estimated data rate is a most recent transmission rate used by the AP.
10. The method of claim 1 , wherein the notifying is achieved by transmitting the calculated maximum receivable size of any A-MPDU in a probe request frame.
11. The method of claim 1 , wherein the notifying is achieved by transmitting the calculated maximum receivable size of any A-MPDU in a re-association request frame.
12. The apparatus of claim 4 , wherein the WLAN communication module is operative to receive the A-MPDU from the AP responsive to transmitting a PS-Poll frame to the AP at the start of the downlink period.
13. The apparatus of claim 4 , wherein the WLAN communication module is operative, responsive to determining a change in the estimated data rate to a new estimated data rate:
to re-calculate the maximum receivable size of any A-MPDU using the new estimated data rate; and
to notify the AP of the re-calculated maximum receivable size of any A-MPDU.
14. The apparatus of claim 13 , wherein the change in the estimated data rate exceeds a threshold value.
15. The apparatus of claim 4 , wherein the estimated data rate is a most recent transmission rate used by the AP.
16. The apparatus of claim 4 , wherein the WLAN communication module is operative to notify the AP by transmitting the calculated maximum receivable size of any A-MPDU in a probe request frame.
17. The apparatus of claim 4 , wherein the WLAN communication module is operative to notify the AP by transmitting the calculated maximum receivable size of any A-MPDU in a re-association request frame.
18. The apparatus of claim 4 , wherein the WLAN communication module is operative to calculate the maximum receivable size of any A-MPDU as a function of an estimated contention window required by the AP to access a wireless medium when transmitting any A-MPDU to the apparatus.