Data transmission method, apparatus, and system

1. A transmit end, comprising;

a processor configured to generate a physical layer protocol data unit (PPDU); and

a transceiver configured to send the PPDU to at least one receive end; wherein the PPDU comprises:

at least one modulated field short training field (STF) that comprises:

a plurality of zero elements; and

a plurality of non-zero elements;

wherein (1) m1 zero elements are included before a first non-zero element, (2) m2 zero elements are included after a last non-zero element, (3) a sum of m1 and m2 zero elements are included between any two adjacent non-zero elements, m1 and m2 both are positive integers, and the at least one modulated field STF is mapped to a plurality of consecutive subcarriers for transmission;

wherein the at least one modulated field STF includes one or more sequences whose lengths are N, each sequence whose length is N is mapped to a subcarrier on one resource block (RB) for transmission, and N is a positive integer;

wherein in response to channel bonding being CB=1, the at least one modulated field STF includes four sequences for which N=88 or four sequences for which N=128, and m1+m2=3, wherein when the at least one modulated field STF includes four sequences for which N=88, a length of the at least one modulated field STF in time domain is equal to 7.5 OFDM symbols carrying no cyclic prefix, and wherein when the at least one modulated field STF includes four sequences for which N=128, a length of the at least one modulated field STF in time domain is equal to five orthogonal frequency division multiplexing (OFDM) symbols carrying no cyclic prefix.

2. The transmit end according to claim 1 , wherein the non-zero elements in the at least one modulated field STF form a Golay sequence.

3. The transmit end according to claim 1 , wherein when the at least one modulated field STF includes four sequences for which N=128, the at least one modulated field STF is generated based on two binary Golay sequences whose lengths each are 32, and the two binary Golay sequences are respectively:

R1=[1, 1, −1, 1, 1, 1, 1, −1, 1, 1, −1, 1, −1, −1, −1, 1, 1, 1, −1, 1, 1, 1, 1, −1, −1, −1, 1, −1, 1, 1, 1, −1]; and

R2=[1, 1, −1, 1, 1, 1, 1, −1, 1, 1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1, −1, −1, −1, 1, 1, 1, −1, 1, −1, −1, −1, 1].

4. The transmit end according to claim 3 , wherein the at least one modulated field STF is obtained by inserting a zero element before and after each non-zero element in G128 (v, :) based on a specified rule, wherein v is a positive integer and a value range meets 1≤v≤8; and

G128 (1, :)=[R1, R2, R1, −R2];

G128 (2, :)=[R1, R2, −R1, R2];

G128 (3, :)=[R2, R1, R2, −R1];

G128 (4, :)=[R2, R1, −R2, R1];

G128 (5, :)=[R1, −R2, R1, R2];

G128 (6, :)=[−R1, R2, R1, R2];

G128 (7, :)=[R2, −R1, R2, R1]; and

G128 (8, :)=[−R2, R1, R2, R1].

5. The transmit end according to claim 1 , wherein when the at least one modulated field STF includes four sequences for which N=88, the at least one modulated field STF is generated based on two quaternary Golay sequences whose lengths each are 22, and the two quaternary Golay sequences are respectively:

S1=[−1i, 1, 1, −1, 1, 1, 1i, −1i, −1, −1, 1, −1, 1i, 1i, −1i, 1i, 1i, 1i, 1, −1, −1i, −1]; and

S2=[−1i, −1, 1, 1, 1, −1, 1i, 1i, −1, 1, 1, 1, 1i, −1i, −1i, −1i, 1i, −1i, 1, 1, −1i, 1].

6. The transmit end according to claim 5 , wherein the at least one modulated field STF is obtained by inserting a zero element before and after each non-zero element in G88 (v, :) based on a specified rule, wherein v is a positive integer and a value range meets 1≤v≤8; and

G88 (1, :)=[S1, S2, S1, −S2];

G88 (2, :)=[S1, S2, −S1, S2];

G88 (3, :)=[S2, S1, S2, −S1];

G88 (4, :)=[S2, S1, −S2, S1];

G88 (5, :)=[S1, −S2, S1, S2];

G88 (6, :)=[−S1, S2, S1, S2];

G88 (7, :)=[S2, −S1, S2, S1]; and

G88 (8, :)=[−S2, S1, S2, S1].

7. A receive end, comprising:

a processor configured to parse a protocol data unit (PPDU); and

a transceiver configured to receive the PPDU from a transmit end; wherein the PPDU comprises:

at least one modulated field short training field (STF) that comprises:

a plurality of zero elements and a plurality of non-zero elements;

m1 zero elements are included before a first non-zero element;

m2 zero elements are included after a last non-zero element;

a sum of the m1 and m2 zero elements are included between any two adjacent non-zero elements; m1 and m2 both are positive integers, and

the at least one modulated field STF is mapped to a plurality of consecutive subcarriers;

wherein the at least one modulated field STF comprises one or more sequences whose lengths are N, each sequence whose length is N is mapped to a subcarrier on one resource block (RB) for transmission, and N is a positive integer; and

wherein in response to channel bonding being CB=1, the at least one modulated field STF includes four sequences for which N=88 or four sequences for which N=128, and m1+m2=3, wherein when the at least one modulated field STF includes four sequences for which N=88, a length of the at least one modulated field STF in time domain is equal to 7.5 OFDM symbols carrying no cyclic prefix, and wherein when the at least one modulated field STF includes four sequences for which N=128, a length of the at least one modulated field STF in time domain is equal to five orthogonal frequency division multiplexing (OFDM) symbols carrying no cyclic prefix.

8. The receive end according to claim 7 , wherein the non-zero elements in at least one a Golay sequence.

9. The receive end according to claim 7 , wherein when the at least one modulated field STF includes four sequences for which N=128, the at least one modulated field STF is generated based on two binary Golay sequences whose lengths each are 32, and the two binary Golay sequences are respectively:

R1=[1, 1, −1, 1, 1, 1, 1, −1, 1, 1, −1, 1, −1, −1, −1, 1, 1, 1, −1, 1, 1, 1, 1, −1, −1, −1, 1, −1, 1, 1, 1, −1]; and

R2=[1, 1, −1, 1, 1, 1, 1, −1, 1, 1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1, −1, −1, −1, 1, 1, 1, −1, 1, −1, −1, −1, 1].

10. The receive end according to claim 9 , wherein the at least one modulated field STF is obtained by inserting a zero element before and after each non-zero element in G128 (v, :) based on a specified rule, wherein v is a positive integer and a value range meets 1≤v≤8; and

G128 (1, :)=[R1, R2, R1, −R2];

G128 (2, :)=[R1, R2, −R1, R2];

G128 (3, :)=[R2, R1, R2, −R1];

G128 (4, :)=[R2, R1, −R2, R1];

G128 (5, :)=[R1, −R2, R1, R2];

G128 (6, :)=[−R1, R2, R1, R2];

G128 (7, :)=[R2, −R1, R2, R1]; and

G128 (8, :)=[−R2, R1, R2, R1].

11. A data transmission system, comprising;

a transmit end, comprising:

a processor configured to generate a physical layer protocol data unit (PPDU);

a transceiver configured to send the PPDU;

a receive end, comprising:

a processor configured to parse the PPDU;

a transceiver configured to receive the PPDU from the transmit end;

wherein the PPDU comprises:

at least one modulated field short training field (STF) that comprises:

a plurality of zero elements; and

a plurality of non-zero elements;

wherein:

m1 zero elements are included before a first non-zero element;

m2 zero elements are included after a last non-zero element,

a sum of m1 and m2 zero elements are included between any two adjacent non-zero elements;

m1 and m2 both are positive integers;

the modulated field STF is mapped to a plurality of consecutive subcarriers for transmission;

the modulated field STF includes one or more sequences whose lengths are N;

each sequence whose length is N is mapped to a subcarrier on one resource block (RB) for transmission, and N is a positive integer;

in response to channel bonding being CB=1, the at least one modulated field STF includes four sequences for which N=88 or four sequences for which N=128, and m1+m2=3, wherein when the at least one modulated field STF includes four sequences for which N=88, a length of the at least one modulated field STF in time domain is equal to 7.5 OFDM symbols carrying no cyclic prefix, and wherein when the at least one modulated field STF includes four sequences for which N=128, a length of the at least one modulated field STF in time domain is equal to five orthogonal frequency division multiplexing (OFDM) symbols carrying no cyclic prefix.

12. The data transmission system according to claim 11 , wherein when the at least one modulated field STF includes four sequences for which N=128, the at least one modulated field STF is generated based on two binary Golay sequences whose lengths each are 32, and the two binary Golay sequences are respectively:

R1=[1, 1, −1, 1, 1, 1, 1, −1, 1, 1, −1, 1, −1, −1, −1, 1, 1, 1, −1, 1, 1, 1, 1, −1, −1, −1, 1, −1, 1, 1, 1, −1]; and

R2=[1, 1, −1, 1, 1, 1, 1, −1, 1, 1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1, −1, −1, −1, 1, 1, 1, −1, 1, −1, −1, −1, 1].

13. The data transmission according to claim 12 , wherein the modulated field STF is obtained by inserting a zero element before and after each non-zero element in G128 (v, :) based on a specified rule, wherein v is a positive integer and a value range meets 1≤v≤8; and

G128 (1, :)=[R1, R2, R1, −R2];

G128 (2, :)=[R1, R2, −R1, R2];

G128 (3, :)=[R2, R1, R2, −R1];

G128 (4, :)=[R2, R1, −R2, R1];

G128 (5, :)=[R1, −R2, R1, R2];

G128 (6, :)=[−R1, R2, R1, R2];

G128 (7, :)=[R2, −R1, R2, R1]; and

G128 (8, :)=[−R2, R1, R2, R1].