Multiple frame transmission
A method for transmitting a physical layer protocol data unit (PPDU) in a transmission opportunity (TXOP) and a device using the same are provided. The device transmits a request to send (RTS) frame to a plurality of receiving stations. The RTS frame includes a bandwidth field and a plurality of allocation fields. The bandwidth field indicates a first bandwidth in which the RTS frame is transmitted. Each allocation field indicates a bandwidth in which a clear to send (CTS) frame is to be sent by a corresponding receiving station. The device determines a transmission bandwidth of a PPDU to be sent by comparing the first bandwidth with a second bandwidth which is a total bandwidth indicated by the plurality of allocation fields.
1. A method for transmitting a physical layer protocol data unit (PPDU) in a transmission opportunity (TXOP), the method performed by an access point (AP) comprising:
checking whether an operating channel is idle, the operating channel including a primary channel and a plurality of secondary channels; and
transmitting 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.
2. The method of claim 1 , wherein, when the operating channel has a bandwidth of 160 MHz, the operating channel includes the primary channel, a secondary 20 MHz channel, a secondary 40 MHz channel and a secondary80 MHz channel, the secondary 80 MHz channel including four secondary 20 MHz subchannels,
wherein the PPDU which is transmitted through the operating channel of 160 MHz is punctured in the secondary 20 MHz channel if the secondary 40 MHz channel and at least one of the four secondary 20 MHz subchannels are idle during an interval of PIFS immediately preceding the start of the TXOP, and
wherein the PPDU which is transmitted through the operating channel of 160 MHz is not punctured in the primary channel and the secondary 20 MHz channel if the secondary 20 MHz channel and at least one of the four secondary 20 MHz subchannels are idle during an interval of PIFS immediately preceding the start of the TXOP.
3. The method of claim 1 , wherein the PPDU includes an L-SIG field, a high efficiency (HE)-SIG-A field and a HE-SIG-B field,
the HE-SIG-A field including information indicating a bandwidth of the operating channel,
the HE-SIG-B field including downlink multi-user multiple input multiple output MU-MIMO) resource allocation information,
the L-SIG field including a length field being set to
⌈
TXTIME
-
20
4
⌉
×
3
-
3
-
m
where TXTIME indicates an estimated time required to transmit the PPDU and m is 1.
4. The method of claim 1 , wherein the PPDU includes a trigger frame for soliciting at least one uplink PPDU transmission.
5. The method of claim 1 , wherein the primary channel has a bandwidth of 20 MHz.
6. 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.
7. The device of claim 6 , wherein, when the operating channel has a bandwidth of 160 MHz, the operating channel includes the primary channel, a secondary 20 MHz channel, a secondary 40 MHz channel and a secondary80 MHz channel, the secondary 80 MHz channel including four secondary 20 MHz subchannels,
wherein the PPDU which is transmitted through the operating channel of 160 MHz is punctured in the secondary 20 MHz channel if the secondary 40 MHz channel and at least one of the four secondary 20 MHz subchannels are idle during an interval of PIFS immediately preceding the start of the TXOP, and
wherein the PPDU which is transmitted through the operating channel of 160 MHz is not punctured in the primary channel and the secondary 20 MHz channel if the secondary 20 MHz channel and at least one of the four secondary 20 MHz subchannels are idle during an interval of PIFS immediately preceding the start of the TXOP.
8. The device of claim 6 , wherein the PPDU includes an L-SIG field, a high efficiency (HE)-SIG-A field and a HE-SIG-B field,
the HE-SIG-A field including information indicating a bandwidth of the operating channel,
the HE-SIG-B field including downlink multi-user multiple input multiple output MU-MIMO) resource allocation information,
the L-SIG field including a length field being set to
⌈
TXTIME
-
20
4
⌉
×
3
-
3
-
m
where TXTIME indicates an estimated time required to transmit the PPDU and m is 1.
9. The device of claim 6 , wherein the PPDU includes a trigger frame for soliciting at least one uplink PPDU transmission.
10. The device of claim 6 , wherein the primary channel has a bandwidth of 20 MHz.