Acknowledgment of uplink orthogonal frequency division multiple access transmission

1. A method for communicating in a wireless communication network, the method comprising:

receiving, at the first communication device, an uplink orthogonal frequency multiple access (OFDMA) transmission, wherein the uplink OFDMA transmission includes respective data units from multiple second communication devices, wherein the respective data units include respective indications of respective acknowledgment policies corresponding to the respective data units, wherein a first acknowledgement policy among the respective acknowledgment policies indicates that a first data unit, among the respective data units, is to be acknowledged prior to any subsequent transmission from any of the multiple second communication devices, and wherein a second acknowledgement policy among the respective acknowledgment policies indicates that a second data unit, among the respective data units, is to be acknowledged only after the corresponding second communication device has transmitted a subsequent data unit in a subsequent uplink OFDMA transmission;

generating, at the first communication device, an acknowledgment physical layer (PHY) data unit to acknowledge at least the first data unit and the second data unit; and

transmitting, with the first communication device, the acknowledgment PHY data unit in a downlink transmission to acknowledge at least the first data unit and the second data unit, including one of:

i) transmitting the downlink transmission prior to any subsequent transmission from any of the multiple second communication devices, or

ii) transmitting the downlink transmission only after receiving the subsequent uplink OFDMA transmission.

2. The method of claim 1 , wherein transmitting the acknowledgment PHY data unit in the downlink transmission comprises:

ignoring, by the first communication device, the second acknowledgement policy indicating that the second data unit is to be acknowledged only after the corresponding second communication device has transmitted the subsequent data unit in the subsequent uplink OFDMA transmission; and

transmitting the downlink transmission prior to the corresponding second communication device transmitting the subsequent data unit in the subsequent uplink OFDMA transmission.

3. The method of claim 2 , wherein transmitting the acknowledgment PHY data unit in the downlink transmission comprises:

beginning the downlink transmission at a predetermined time period after an end of the uplink OFDMA transmission.

4. The method of claim 3 , wherein the first acknowledgement policy indicates that the first data unit is to be acknowledged beginning at the predetermined time period after the end of the uplink OFDMA transmission.

5. The method of claim 1 , wherein transmitting the acknowledgment PHY data unit in the downlink transmission comprises:

ignoring, by the first communication device, the first acknowledgement policy indicating that the first data unit is to be acknowledged prior to any subsequent transmission from any of the multiple second communication devices; and

transmitting the downlink transmission only after receiving the subsequent uplink OFDMA transmission.

6. The method of claim 1 , wherein generating the acknowledgment PHY data unit comprises:

generating the acknowledgment PHY data unit to include multiple acknowledgment frames in respective component channels.

7. The method of claim 6 , wherein generating the acknowledgment PHY data unit further comprises:

generating the acknowledgment PHY data unit to include multiple acknowledgment frames in a single component channel using spatial division multiple access (SDMA).

8. The method of claim 1 , wherein generating the acknowledgment PHY data unit comprises:

generating the acknowledgment PHY data unit to include a broadcast acknowledgement frame, the broadcast acknowledgment frame indicating respective block acknowledgements for multiple second communication devices.

9. The method of claim 8 , wherein the broadcast acknowledgement frame is a multi-user block acknowledgement (M-BA) frame.

10. The method of claim 1 , wherein generating the acknowledgment PHY data unit comprises generating at least:

a first acknowledgment PHY data unit to acknowledge one or more respective transmissions in the uplink OFDMA transmission from a first set of one or more second communication devices; and

a second acknowledgment PHY data unit to acknowledge one or more respective transmissions in the uplink OFDMA transmission from a second set of one or more second communication devices.

11. A wireless communication device, comprising:

a wireless network interface device associated with a first communication device, wherein the wireless network interface device includes one or more integrated circuits (ICs) configured to:

receive an uplink orthogonal frequency multiple access (OFDMA) transmission, wherein the uplink OFDMA transmission includes respective data units from multiple second communication devices, wherein the respective data units include respective indications of respective acknowledgment policies corresponding to the respective data units, wherein a first acknowledgement policy among the respective acknowledgment policies indicates that a first data unit, among the respective data units, is to be acknowledged prior to any subsequent transmission from any of the multiple second communication devices, and wherein a second acknowledgement policy among the respective acknowledgment policies indicates that a second data unit, among the respective data units, is to be acknowledged only after the corresponding second communication device has transmitted a subsequent data unit in a subsequent uplink OFDMA transmission,

generate an acknowledgment physical layer (PHY) data unit to acknowledge at least the first data unit and the second data unit, and

transmit the acknowledgment PHY data unit in a downlink transmission to acknowledge at least the first data unit and the second data unit, including one of:

i) transmitting the downlink transmission prior to any subsequent transmission from any of the multiple second communication devices, or

ii) transmitting the downlink transmission only after receiving the subsequent uplink OFDMA transmission.

12. The wireless communication device of claim 11 , wherein the one or more ICs are further configured to:

ignore the second acknowledgement policy indicating that the second data unit is to be acknowledged only after the corresponding second communication device has transmitted the subsequent data unit in the subsequent uplink OFDMA transmission; and

transmit the downlink transmission prior to the corresponding second communication device transmitting the subsequent data unit in the subsequent uplink OFDMA transmission.

13. The wireless communication device of claim 12 , wherein the one or more ICs are further configured to:

begin the downlink transmission at a predetermined time period after an end of the uplink OFDMA transmission.

14. The wireless communication device of claim 13 , wherein the first acknowledgement policy indicates that the first data unit is to be acknowledged beginning at the predetermined time period after the end of the uplink OFDMA transmission.

15. The wireless communication device of claim 11 , wherein the one or more ICs are further configured to:

ignore the first acknowledgement policy indicating that the first data unit is to be acknowledged prior to any subsequent transmission from any of the multiple second communication devices; and

transmit the downlink transmission only after receiving the subsequent uplink OFDMA transmission.

16. The wireless communication device of claim 11 , wherein the one or more ICs are further configured to:

generate the acknowledgment PHY data unit to include multiple acknowledgment frames in respective component channels.

17. The wireless communication device of claim 16 , wherein the one or more ICs are further configured to:

generate the acknowledgment PHY data unit to include multiple acknowledgment frames in a single component channel using spatial division multiple access (SDMA).

18. The wireless communication device of claim 11 , wherein the one or more ICs are further configured to:

generate the acknowledgment PHY data unit to include a broadcast acknowledgement frame, the broadcast acknowledgment frame indicating respective block acknowledgements for multiple second communication devices.

19. The wireless communication device of claim 18 , wherein the broadcast acknowledgement frame is a multi-user block acknowledgement (M-BA) frame.

20. The wireless communication device of claim 11 , wherein the one or more ICs are further configured to generate the acknowledgment PHY data unit comprises at least be generating:

a first acknowledgment PHY data unit to acknowledge one or more respective transmissions in the uplink OFDMA transmission from a first set of one or more second communication devices; and

a second acknowledgment PHY data unit to acknowledge one or more respective transmissions in the uplink OFDMA transmission from a second set of one or more second communication devices.