Multi-channel hybrid transmission method and apparatus in wireless local area network

1. A data transmission method for wireless local area networks, the method comprising:

generating, by a first wireless communications device, a physical protocol data unit (PPDU), wherein the PPDU comprises a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), and two signature symbols after the L-SIG in a time-domain, and wherein the two signature symbols are identical and are modulated based on binary phase shift keying (BPSK), the two signature symbols identify a wireless communications standard the PPDU complies with; and

transmitting, by the first wireless communications device, the PPDU to a second wireless communications device.

2. The method according to claim 1 , wherein each of the two signature symbols comprises a predetermined signature field that includes information known by the first communications device and the second communications device.

3. The method according to claim 1 , wherein the each of the two signature symbols comprises a pilot sequence carried by four subcarriers with corresponding subcarrier indexes −28, −27, 27, 28.

4. The method according to claim 3 , wherein the pilot sequence is used for channel estimation.

5. A data transmission method for wireless local area networks, the method comprising:

receiving, by a first wireless communications device from a second wireless communications device, a physical protocol data unit (PPDU), wherein the PPDU comprises a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), and two signature symbols after the L-SIG in a time-domain, and wherein the two signature symbols are identical and are modulated based on binary phase shift keying (BPSK), the

two signature symbols identify a wireless communications standard the PPDU complies with; and

determining, by the first wireless communications device, the wireless communications standard that the PPDU complies with based on the two signature symbols.

6. The method according to claim 5 , wherein each of the two signature symbols comprises a predetermined signature field that includes information known by the first communications device and the second communications device.

7. The method according to claim 5 , wherein the each of the two signature symbols comprises a pilot sequence carried by four subcarriers with corresponding subcarrier indexes −28, −27, 27, 28.

8. The method according to claim 7 , wherein the pilot sequence is used for channel estimation.

9. A wireless apparatus comprising:

at least one processor; and

a non-transitory computer readable storage medium storing programming instructions for execution by the at least one processor, the programming instructions, when executed by the at least one processor, instructing the wireless apparatus to:

generate a physical protocol data unit (PPDU), wherein the PPDU comprises a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), and two signature symbols after the L-SIG in a time-domain,

and wherein the two signature symbols are identical and are modulated based on binary phase shift keying (BPSK), the

two signature symbols identify a wireless communications standard the PPDU complies with; and

transmit the PPDU to another wireless apparatus.

10. The wireless apparatus according to claim 9 , wherein each of the two signature symbols comprises a predetermined signature field that includes information known by the wireless apparatus and the another wireless apparatus.

11. The wireless apparatus according to claim 9 , wherein the each of the two signature symbols comprises a pilot sequence carried by four subcarriers with corresponding subcarrier indexes −28, −27, 27, 28.

12. The wireless apparatus according to claim 11 , wherein the pilot sequence is used for channel estimation.

13. A wireless apparatus comprising:

at least one processor; and

a non-transitory computer readable storage medium storing programming instructions for execution by the processor, the programming instructions, when executed by the at least one processor, instructing the wireless apparatus to:

receive, from another wireless apparatus, a physical protocol data unit (PPDU), wherein the PPDU comprises a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), and two signature symbols after the L-SIG in a time-domain,

and wherein the two signature symbols are identical and are modulated based on binary phase shift keying (BPSK), the

two signature symbols identify a wireless communications standard the PPDU complies with; and

determine, the wireless communications standard that the PPDU complies with based on the two signature symbols.

14. The wireless apparatus according to claim 13 , wherein each of the two signature symbols comprises a predetermined signature field that includes information known by the wireless apparatus and the another wireless apparatus.

15. The wireless apparatus according to claim 13 , wherein the each of the two signature symbols comprises a pilot sequence carried by four subcarriers with corresponding subcarrier indexes −28, −27, 27, 28.

16. The wireless apparatus according to claim 15 , wherein the pilot sequence is used for channel estimation.