Method for transmitting and receiving frame performed by station operating in power save mode in wireless local area network system and apparatus for the same

1. A method for managing a power in a wireless local area network, the method comprising:

transmitting, by a station (STA) in a power save mode, a PS poll frame to an access point (AP) in a first 20 MHz channel;

transmitting, by the STA in the power save mode, at least one duplicated PS poll frame to the AP in at least one second 20 MHz channel, the at least one duplicated PS poll frame being generated by duplicating the PS poll frame; and

receiving, by the STA, a bufferable frame from the AP as a response of at least one of the PS poll frame and the at least one duplicated PS poll frame.

2. The method of claim 1 ,

wherein the PS poll frame and the at least one duplicated PS poll frame respectively comprise a data field,

wherein the data field is scrambled based on a specific scrambling sequence,

wherein the data field comprises a transmitter address (TA) field set to a bandwidth signaling TA, and

wherein the bandwidth signaling TA indicates an address of the STA, and

the specific scrambling sequence includes first bandwidth information.

3. The method of claim 2 ,

wherein the first bandwidth information indicates a bandwidth for the PS poll frame and the at least one duplicated PS poll frame.

4. The method of claim 3 ,

wherein the PS poll frame and the at least one duplicated PS poll frame further respectively comprises a VHT-SIG-A field including a bandwidth field,

wherein the VHT-SIG-A field is generated based on second bandwidth information, and

wherein the second bandwidth information is same as the first bandwidth information.

5. The method of claim 2 , further comprising:

receiving, by the STA in the power save mode, an acknowledgement (ACK) frame from the AP for acknowledging the PS poll frame and the at least one duplicated PS poll frame.

6. The method of claim 5 ,

wherein the ACK frame comprises a receiver address (RA) field,

wherein the RA field is set to a non-bandwidth signaling TA obtained in basis of the TA field in at least one of the PS poll frame and the at least one duplicated PS poll frame.

7. The method of claim 1 ,

wherein the number of the at least one secondary 20 MHz channel is one, and

wherein the first 20 Mhz channel is contiguous with the secondary 20 MHz channel.

8. The method of claim 1 ,

wherein the number of the at least one secondary 20| MHz channel is three, and

wherein the first 20 MHz channel is contiguous with the contiguous three secondary 20 MHz channels.

9. The method of claim 1 ,

wherein the number of the at least one secondary 20 MHz channel is seven, and

wherein the first 20 MHz channel is contiguous with the contiguous seven secondary 20 MHz channels.

10. The method of claim 1 ,

wherein the number of the at least one secondary 20 MHz is seven,

wherein the first 20 MHz channel is contiguous with three 20 MHz secondary channels among the seven secondary 20 MHz channels, and

wherein the first 20 MHz channel and the three 20 MHz secondary channels are not contiguous with the remaining four secondary 20 MHz channels.

11. The method of claim 1 , further comprising

receiving, by the STA in the power save mode, a Traffic Indication Map (TIM) element from the AP; and

determining, by the STA in the power save mode, whether the bufferable frame is buffered for the STA based on the TIM element;

wherein if it is determined that the bufferable frame is buffered, the PS poll frame and the at least one PS poll frame is transmitted.

12. A wireless apparatus in a wireless local area network comprising:

a transceiver transmits and receives frames; and

a processor is configures to the transceiver, wherein the processor is configured to:

transmit a power save (PS) poll frame to an access point (AP) in a first 20 MHz channel,

transmit at least one duplicated PS poll frame to the AP in at least one second 20 MHz channel, the at least one duplicated PS poll frame being generated by duplicating the PS poll frame, and

receive a bufferable frame from the AP as a response of at least one of the PS poll frame and the at least one duplicated PS poll frame.