Group acknowledgement for multiple user communication in a wireless local area network

1. A method for simultaneously communicating with multiple communication devices in a wireless local area network, the method comprising:

receiving, at a first communication device, a plurality of uplink data units simultaneously transmitted by multiple second communication devices;

generating, at the first communication device, an acknowledgement data unit to acknowledge receipt of the plurality of uplink data units simultaneously transmitted by the multiple second communication devices, wherein the acknowledgement data unit includes a plurality of acknowledgment fields corresponding to ones of the multiple second communication devices, wherein each of at least some of the plurality of acknowledgment fields include:

a first field that includes an indicator of a corresponding one of the multiple second communication devices,

a second field that indicates whether the acknowledgment field corresponds to i) an acknowledgment corresponding to a single data unit received from the corresponding one of the second communication devices, or ii) a block acknowledgment corresponding to multiple data units received from the corresponding one of the multiple second communication devices,

wherein when the second field indicates the block acknowledgment corresponding to a group of multiple data units, the acknowledgment field further includes a third field having a bitmap that indicates which of the multiple data units in the group are being acknowledged, and

wherein when the second field indicates acknowledgment of a single data unit, the acknowledgment field does not include the third field; and

controlling one or more transceivers of the first communication device to transmit the acknowledgement data unit;

wherein a first acknowledgment field among the plurality of acknowledgment fields i) corresponds to the block acknowledgment corresponding to the multiple data units, and ii) includes the third field; and

wherein a second acknowledgment field among the plurality of acknowledgment fields i) corresponds to the acknowledgment corresponding to the single data unit, and ii) does not include the third field.

2. The method of claim 1 , wherein the plurality of acknowledgment fields correspond to multiple acknowledgements of data units corresponding to multiple traffic identifiers (TIDs).

3. The method of claim 1 , wherein:

when the second field indicates the block acknowledgment corresponding to the group of multiple data units,

the group of multiple data units corresponds to an ordered sequence of data units, each data unit in the sequence corresponding to a respective sequence number,

the acknowledgment field further includes a fourth field that indicates a starting sequence number, and

bits in the bitmap correspond to respective offsets from the starting sequence number; and

when the second field indicates acknowledgment of the single data unit, the acknowledgment field does not include the fourth field.

4. The method of claim 1 , wherein when the second field indicates acknowledgment of the single data unit, the acknowledgment field corresponds to acknowledgment of a single media access control (MAC) protocol data unit (MPDU).

5. The method of claim 4 , wherein when the second field indicates the block acknowledgment, the acknowledgment field corresponds to acknowledgment of one or more individual MPDUs included within an aggregated MPDU (A-MPDU).

6. The method of claim 1 , wherein the indicator of the corresponding one of the second communication devices includes a partial association identifier (PAID) associated with the corresponding one of the multiple second communication devices.

7. The method of claim 1 , further comprising selecting, at the first communication device, one or more of (i) a data rate, (ii) a modulation and coding scheme (MCS) and (iii) a number of spatial streams (Nss) to be used for transmission of the acknowledgement data unit to the multiple second communication devices, wherein the one or more of (i) the data rate, (ii) the MCS and (iii) the Nss are selected without considering corresponding one or more parameters of the received uplink data units.

8. The method of claim 1 , further comprising, prior to receiving the plurality of uplink data units simultaneously transmitted by the multiple second communication devices, transmitting, by the first communication device, a control frame that prompts transmission of the plurality of uplink data units by the multiple second communication devices.