Multiple frame transmission

A device for transmitting a physical layer protocol data unit (PPDU) in a transmission opportunity (TXOP), the device comprising:

• a processor;
• and
• a memory operatively coupled with the processor and storing instructions that when executed by the processor cause the device to:
• check whether an operating channel is idle, the operating channel including a primary channel and a plurality of secondary channels;
• and
• transmit a PPDU through the operating channel if the primary channel and at least one secondary channel in the operating channel are idle,
• wherein the PPDU is punctured in at least one secondary channel of the operating channel which is not idle,
• wherein, when the operating channel has a bandwidth of 80 MHz, the operating channel includes the primary channel, a secondary 20 MHz channel and a secondary 40 MHz channel, the secondary 40 MHz channel including two secondary 20 MHz subchannels,
• wherein the PPDU which is transmitted through the operating channel of 80 MHz is punctured in the secondary 20 MHz if the secondary 40 MHz channel is idle during an interval of point coordination function interframe space (PIFS) immediately preceding a start of the TXOP, and
• wherein the PPDU which is transmitted through the operating channel of 80 MHz is punctured in one of the two secondary 20 MHz subchannels if the secondary 20 MHz channels and the other of the two secondary 20 MHz subchannels are idle during an interval of PIFS immediately preceding the start of the TXOP.