Data transmission method and apparatus
A data transmission method includes that a first device sends a physical layer protocol data unit (PPDU) to a second device. A bandwidth of channels occupied by the PPDU is N×20 megahertz (MHz), the PPDU includes a preamble sequence having a backward compatibility function and a first extremely high throughput long training field (EHT-LTF), the first EHT-LTF is carried in a first subcarrier set, the first subcarrier set includes one or more subcarriers other than a subcarrier that carries the preamble sequence having the backward compatibility function and a direct current subcarrier in the N 20 MHz channels, and N is a positive integer greater than or equal to 2. The second device receives the PPDU sent by the first device.
1. A method comprising:
receiving, from a first device, a physical layer protocol data unit (PPDU) occupying N 20 megahertz (MHz) channels having a total bandwidth of Nx20 MHz,
wherein the PPDU comprises a preamble sequence having a backward compatibility function and a first extremely high throughput long training field (EHT-LTF),
wherein the first EHT-LTF is in a first subcarrier set, wherein the first subcarrier set comprises one or more first subcarriers other than a second subcarrier that carries the preamble sequence and other than a direct current subcarrier in the N 20 MHz channels,
wherein a subcarrier in the N 20 MHz channels and subcarriers at two ends of the N 20 MHz channels are used to send the EHT-LTF, and
wherein N is a positive integer greater than or equal to two.
2. The method of claim 1 , wherein the first subcarrier set further comprises one or more third subcarriers other than the second subcarrier and the direct current subcarrier in every two of the N 20 MHz channels.
3. The method of claim 1 , wherein the PPDU further comprises an extremely high throughput signal (EHT-SIG) field located in a second time unit, wherein the preamble sequence comprises a legacy signal (L-SIG) field having the backward compatibility function and located in a first time unit, and wherein the first EHT-LTF is located in:
the first time unit;
the second time unit; or
a third time unit between the first time unit and the second time unit.
4. The method of claim 3 , wherein the L-SIG field comprises a rate field indicating that a transmission rate of the PPDU is a first transmission rate, and wherein the method further comprises identifying, using the first transmission rate, a format of the PPDU.
5. The method of claim 3 , wherein the PPDU comprises data carried on at least one resource unit, wherein the EHT-SIG field indicates either a first quantity of the at least one resource unit or a second quantity of remaining resource units in the at least one resource unit.
6. The method of claim 5 , wherein the data comprises at least one physical layer service data unit (PSDU) carried on the at least one resource unit according to a predefined rule.
7. The method of claim 3 , wherein the PPDU further comprises a redundant L-SIG (RL-SIG) field located in a fourth time unit, and wherein the third time unit sequentially immediately follows the first time unit.
8. The method of claim 1 , wherein the PPDU further comprises an extremely high throughput short training field (EHT-STF) and a second EHT-LTF.
9. A device comprising:
a processor configured to generate a physical layer protocol data unit (PPDU) occupying N 20 megahertz (MHz) channels having-a total bandwidth of N×20 MHz, wherein the PPDU comprises a preamble sequence having a backward compatibility function and an extremely high throughput long training field (EHT-LTF), wherein the EHT-LTF is in a first subcarrier set, wherein the first subcarrier set comprises one or more first subcarriers other than a second subcarrier that carries the preamble sequence and a direct current subcarrier in the N 20 MHz channels, wherein a subcarrier in the N 20 MHz channels and subcarriers at two ends of the N 20 MHz channels are used to send the EHT-LTF; and wherein N is a positive integer greater than or equal to two; and
a transceiver coupled to the processor and configured to send the PPDU to another device.
10. The device of claim 9 , wherein the first subcarrier set further comprises one or more third subcarriers other than the second subcarrier and the direct current subcarrier in every two of the N 20 MHz channels.
11. The device of claim 9 , wherein the PPDU further comprises an extremely high throughput signal (EHT-SIG) field located in a second time unit, wherein the preamble sequence comprises a legacy signal (L-SIG) field having the backward compatibility function and is located in a first time unit, and wherein the EHT-LTF is located in:
the first time unit;
the second time unit; or
a third time unit between the first time unit and the second time unit.
12. The device of claim 11 , wherein the L-SIG field comprises a rate field indicating that a transmission rate of the PPDU is a first transmission rate, and wherein the first transmission rate enables another device to identify a format of the PPDU.
13. The device of claim 11 , wherein the PPDU comprises data carried on at least one resource unit, and wherein the EHT-SIG field indicates either a first quantity of the at least one resource unit or a second quantity of remaining resource units in the at least one resource unit.
14. A device comprising:
a transceiver configured to receive, from another device, a physical layer protocol data unit (PPDU) occupying N 20 megahertz (MHz) channels having a total bandwidth of N×20 MHz, wherein the PPDU comprises a preamble sequence having a backward compatibility function and an extremely high throughput long training field (EHT-LTF), wherein the EHT-LTF is in a first subcarrier set, wherein the first subcarrier set comprises one or more first subcarriers other than a second subcarrier that carries the preamble sequence and a direct current subcarrier in the N 20 MHz channels, wherein a subcarrier in the N 20 MHz channels and subcarriers at two ends of the N 20 MHz channels are used to send the EHT-LTF, and wherein N is a positive integer greater than or equal to two; and
a processor coupled to the transceiver and configured to obtain the PPDU.
15. The device of claim 14 , wherein the first subcarrier set further comprises one or more third subcarriers other than the second subcarrier and the direct current subcarrier in every two of the N 20 MHz channels.
16. The device of claim 14 , wherein the PPDU further comprises an extremely high throughput signal (EHT-SIG) field located in a second time unit, wherein the preamble sequence comprises a legacy signal (L-SIG) field having the backward compatibility function and is located in a first time unit, and wherein the EHT-LTF is located in:
the first time unit;
the second time unit; or
a third time unit between the first time unit and the second time unit.
17. The device of claim 16 , wherein the L-SIG field comprises a rate field indicating that a transmission rate of the PPDU is a first transmission rate, and wherein the processor is further configured to identify, using the first transmission rate, a format of the PPDU.
18. The device of claim 16 , wherein the PPDU comprises data carried on at least one resource unit, and wherein the EHT-SIG field indicates either a first quantity of the at least one resource unit or a second quantity of remaining resource units in the at least one resource unit.
19. The device of claim 18 , wherein the data comprises at least one physical layer service data unit (PSDU) carried on the at least one resource unit according to a predefined rule.
20. The device of claim 16 , wherein the PPDU further comprises a redundant L-SIG (RL-SIG) field located in a fourth time unit, and wherein the fourth time unit sequentially immediately follows the first time unit.