Method and device for transmitting ack ppdu

The method of claim 4

• wherein the first FFT size is 64 and the second FFT size is 256 when the operating bandwidth is 20 MHz;
• wherein the first FFT size is 128 and the second FFT size is 512 when the operating bandwidth is 40 MHz;
• wherein the first FFT size is 256 and the second FFT size is 1024 when the operating bandwidth is 80 MHz;
• and
• wherein the first FFT size is 512 and the second FFT size is 2048 when the operating bandwidth is 160 MHz.

A device for communicating in a wireless local area network, the device comprising:

• a radio frequency module configured to transmit and receive radio signals;
• a processor operatively coupled with the radio frequency module;
• and
• memory disposed to said processor, said memory including instructions, when executed by said processor, causes the processor to:
• process a plurality of uplink (UL) physical layer protocol data units (PPDUs) received from a plurality of stations;
• cause the radio frequency module to transmit, when a first type of acknowledgment is selected, a broadcast acknowledgement (ACK) frame to the plurality of stations, the broadcast ACK frame comprising a first block acknowledgement;
• and
• cause the radio frequency module to transmit, when a second type of acknowledgment is selected, an acknowledgment physical layer protocol data unit (ACK PPDU), the ACK PPDU comprising a first signal field, a second signal field and a data portion,
• wherein the first signal field comprises bandwidth information, the bandwidth information indicating a bandwidth over which the ACK PPDU is transmitted,
• wherein the data portion comprises a second block acknowledgement,
• wherein the first signal field has a first rotated phase over at least one first subcarrier group, each first subcarrier group having bandwidth of 20 MHz, and
• the second signal field has a second rotated phase over a plurality of second subcarrier groups, each second subcarrier group having bandwidth that is less than 20 MHz.

A method of communicating in a wireless local area network, the method comprising:

• receiving a plurality of uplink (UL) physical layer protocol data units (PPDUs) from a plurality of stations;
• and
• transmitting, in response to the received US PPDU's, an acknowledgement physical layer protocol data unit (ACK PPDU), the ACK PPDU comprising a first signal field, a second signal field and a data portion,
• wherein the first signal field comprises bandwidth information, the bandwidth information indicating a bandwidth over which the ACK PPDU is transmitted,
• wherein the data portion comprises the block acknowledgement for the plurality of UL PPDUs,
• wherein the first signal field having a first rotated phase over at least one first subcarrier group, each first subcarrier group having bandwidth of 20 MHz, and
• the second signal field having a second rotated phase over a plurality of second subcarrier groups, each second subcarrier group having bandwidth that is less than 20 MHz.