Communication method, communication apparatus, and communication device

1. A communication apparatus, comprising:

a processor configured to generate a physical layer protocol data unit (PPDU) comprising a preamble, wherein the preamble comprises a legacy physical layer preamble and a second physical layer preamble, wherein the legacy physical layer preamble comprises a preset field, and wherein the second physical layer preamble comprises a repeated field that has a preset out-of-order relationship with the preset field in a frequency domain; and

a transmitter coupled to the processor and configured to send the PPDU.

2. The communication apparatus of claim 1 , wherein the processor is further configured to:

generate, using a first frequency-domain processing process, a first orthogonal frequency-division multiplexing (OFDM) symbol of the preset field; and

generate, using a second frequency-domain processing process, a second OFDM symbol of the repeated field,

wherein the first frequency-domain processing process comprises an interleaving processing and the second frequency-domain processing process does not comprise the interleaving processing, the first frequency-domain processing process does not comprise a scrambling processing and the second frequency-domain processing process comprises the scrambling processing, or the first frequency-domain processing process does not comprise an out-of-order processing for a data symbol and the second frequency-domain processing process comprises the out-of-order processing for the data symbol.

3. The communication apparatus of claim 2 , wherein the processor is further configured to perform the out-of-order processing at least in part by:

performing a cyclic shift on first data symbols carried on data subcarriers;

interchanging second data symbols carried on odd-numbered data subcarriers with third data symbols carried on even-numbered data subcarriers; or

interchanging fourth data symbols carried in a high-frequency data subcarrier subset with fifth data symbols carried in a low-frequency data subcarrier subset.

4. The communication apparatus of claim 2 , wherein the processor is further configured to use a binary phase-shift keying (BPSK) mode for a constellation point mapping in the second frequency-domain processing process.

5. The communication apparatus of claim 1 , wherein the legacy physical layer preamble is decodable by a plurality of receive ends, and wherein the second physical layer preamble is decodable by a portion of the receive ends.

6. The communication apparatus of claim 1 , wherein, in a frequency-domain processing process, a first bit input to a channel encoder for the repeated field is the same as a second bit input to the channel encoder for the preset field.

7. The communication apparatus of claim 1 , wherein the preset field is a legacy signal (L-SIG) field.

8. The communication apparatus of claim 1 , wherein the repeated field is a first field of the second physical layer preamble or a second field of the second physical layer preamble.

9. The communication apparatus of claim 1 , wherein the repeated field is a first field of the second physical layer preamble, and wherein the processor is further configured to use a rotated binary phase-shift keying (BPSK) mode for a constellation point mapping on any field of the second physical layer preamble other than the first field.

10. A communication apparatus, comprising:

a receiver configured to receive a physical layer protocol data unit (PPDU) comprising a preamble, wherein the preamble comprises a legacy physical layer preamble and a second physical layer preamble, and wherein the legacy physical layer preamble comprises a preset field; and

a processor coupled to the receiver and configured to:

determine whether the second physical layer preamble comprises a repeated field that has a preset out-of-order relationship with the preset field in a frequency domain; and

determine that the PPDU is a target PPDU when the second physical layer preamble comprises the repeated field.

11. The communication apparatus of claim 10 , wherein the processor is further configured to:

obtain first information by performing a first decoding processing process on the preset field;

obtain second information by performing a second decoding processing process on the repeated field;

determine a similarity between the first information and the second information;

determine that the second physical layer preamble comprises the repeated field when the similarity is greater than or equal to a preset threshold; and

determine that the second physical layer preamble does not comprise the repeated field when the similarity is less than the preset threshold.

12. The communication apparatus of claim 11 , wherein:

the first decoding processing process comprises a de-interleaving processing, and the second decoding processing process does not comprise the de-interleaving processing;

the first decoding processing process does not comprise a de-scrambling processing, and the second decoding processing process comprises the de-scrambling processing; or

the first decoding processing process does not comprise a de-out-of-order processing for a data symbol, and the second decoding processing process comprises the de-out-of-order processing for the data symbol.

13. The communication apparatus of claim 12 , wherein the processor is further configured to perform the de-out-of-order processing for the data symbol at least in part by:

performing a cyclic shift on first data symbols carried on data subcarriers;

interchanging second data symbols carried on odd-numbered even-numbered data subcarriers with third data symbols carried on even-numbered data subcarriers; or

interchanging fourth data symbols carried in a high-frequency data subcarrier subset with fifth data symbols carried in a low-frequency data subcarrier subset.

14. A communication method, comprising:

generating a physical layer protocol data unit (PPDU) comprising a preamble, wherein the preamble comprises a legacy physical layer preamble and a second physical layer preamble, wherein the legacy physical layer preamble comprises a preset field, and wherein the second physical layer preamble comprises a repeated field that has a preset out-of-order relationship with the preset field in a frequency domain; and

sending the PPDU.

15. The method of claim 14 , further comprising:

generating, using a first frequency-domain processing process, a first orthogonal frequency-division multiplexing (OFDM) symbol of the preset field; and

generating, using a second frequency-domain processing process, a second OFDM symbol of the repeated field,

wherein the first frequency-domain processing process comprises an interleaving processing, and the second frequency-domain processing process does not comprise the interleaving processing; the first frequency-domain processing process does not comprise a scrambling processing, and the second frequency-domain processing process comprises the scrambling processing; or the first frequency-domain processing process does not comprise an out-of-order processing for a data symbol, and the second frequency-domain processing process comprises the out-of-order processing for the data symbol.

16. The method of claim 15 , wherein the out-of-order processing comprises:

performing a cyclic shift on first data symbols carried on data subcarriers;

interchanging second data symbols carried on odd-numbered data subcarriers with third data symbols carried on even-numbered data subcarriers; or

interchanging fourth data symbols carried in a high-frequency data subcarrier subset with fifth data symbols carried in a low-frequency data subcarrier subset.

17. The method of claim 15 , further comprising using a binary phase-shift keying (BPSK) mode for a constellation point mapping in the second frequency-domain processing process.

18. The method of claim 14 , wherein the legacy physical layer preamble can be decoded by a plurality of receive ends, and wherein the second physical layer preamble can be decoded by a portion of the receive ends.

19. The method of claim 14 , wherein, in a frequency-domain processing process, a first bit input to a channel encoder for the repeated field is the same as a second bit input to the channel encoder for the preset field.

20. The method of claim 14 , wherein the preset field is a legacy signal (L-SIG) field.