Communication method and communications apparatus

1. A communications apparatus comprising:

a processor; and

a transceiver,

wherein, the processor is configured to generate first indication information, wherein the first indication information is used to indicate a precoding matrix, the precoding matrix is applied to at least one antenna panel and comprises at least one precoding vector, each precoding vector comprising at least one subvector, each subvector corresponds to an antenna port on the antenna panel and comprises two polarization vectors, and each polarization vector is generated by performing a weighted combination on a plurality of basis vectors, and

the transceiver is configured to send the first indication information,

wherein the two polarization vectors comprise a first polarization vector and a second polarization vector that respectively correspond to two polarization directions of a dual polarization antenna.

2. The communications apparatus according to claim 1 , wherein

the precoding matrix is:

1

α

⁡

[

P

1

P

2

…

P

r

]

,

wherein

P l is the precoding vector, r≥l≥1, r≥1, r represents a quantity of data layers,

1

α

is a normalized coefficient, and

0

<

1

α

≤

1

;

the precoding vector P l is:

[

S

1

l

S

2

l

⋮

S

N

g

l

]

,

wherein

S i l is a subvector of the precoding vector P l , N g ≥i≥1, N g ≥1, and N g is a quantity of the at least one antenna panel; and

the subvector S i l is:

[

Q

1

,

i

l

Q

2

,

i

l

]

,

wherein

Q x,i l is a polarization vector of the subvector S i l , and x is equal to 1 or 2.

3. The communications apparatus according to claim 2 , wherein

Q

x

,

i

l

=

∑

m

=

1

L

⁢

A

m

,

x

,

i

l

⁢

B

m

,

wherein

B m is the basis vector, L≥m>1, L≥2, and A m,x,i l is a weight of the basis vector B m .

4. The communications apparatus according to claim 3 , wherein B m is a Kronecker product of two vectors, a dimension of one vector is N 1 , a dimension of the other vector is N 2 , a dimension of B m is N 1 N 2 , and each antenna panel has N 1 antenna port pairs in a first dimension and N 2 antenna port pairs in a second dimension.

5. The communications apparatus according to claim 3 , wherein

A m,x,i l =a m,x,i l p m,x,i l , wherein

a m,x,i l represents an amplitude coefficient, and p m,x,i l represents a phase coefficient.

6. The communications apparatus according to claim 5 , wherein

A m,2,i l =φ m A m,1,i l , wherein

φ m represents a polarization phase factor, and the first indication information is used to indicate B m , φ m , a m,1,i l , and p m,1,i l .

7. The communications apparatus according to claim 3 , wherein

A m,x,i l =c i l a m,x,i l p m,x,i l , wherein

a m,x,i l represents an amplitude coefficient, p m,x,i l represents a phase coefficient, and c i l represents an antenna panel phase factor.

8. The communications apparatus according to claim 7 , wherein c i l =1, and the first indication information is used to indicate B m , c i l (i≠1), a m,x,i l , and p m,x,i l .

9. The communications apparatus according to claim 7 , wherein c i l is equal to 0 or 1, and the first indication information is used to indicate B m , c i l , a m,x,i l , and p m,x,i l .

10. A communications apparatus comprising:

a processor; and

a transceiver,

wherein, the transceiver is configured to receive first indication information, wherein the first indication information is used to indicate a precoding matrix, the precoding matrix is applied to at least one antenna panel and comprises at least one precoding vector, each precoding vector comprising at least one subvector, each subvector corresponds to an antenna port on the antenna panel and comprises two polarization vectors, and each polarization vector is generated by performing a weighted combination on a plurality of basis vectors, and

the processor is configured to determine the precoding matrix based on the first indication information,

wherein the two polarization vectors comprise a first polarization vector and a second polarization vector that respectively correspond to two polarization directions of a dual polarization antenna.

11. The communications apparatus according to claim 10 , wherein

the precoding matrix is:

1

α

⁡

[

P

1

P

2

…

P

r

]

,

wherein

P l is the precoding vector, r≥l≥1, r≥1, r represents a quantity of data layers,

1

α

is a normalized coefficient, and

0

<

1

α

≤

1

;

the precoding vector P l is:

[

S

1

l

S

2

l

⋮

S

N

g

l

]

,

wherein

S i l is a subvector of the precoding vector P l , N g ≥i≥1, N g ≥1, and N g is a quantity of the at least one antenna panel; and

the subvector S i l is:

[

Q

1

,

i

l

Q

2

,

i

l

]

,

wherein

Q x,i l is a polarization vector of the subvector S i l , and x is equal to 1 or 2.

12. The communications apparatus according to claim 11 , wherein

Q

x

,

i

l

=

∑

m

=

1

L

⁢

A

m

,

x

,

i

l

⁢

B

m

,

wherein

B m is the basis vector, L≥m>1, L≥2, and A m,x,i l is a weight of the basis vector B m .

13. The communications apparatus according to claim 12 , wherein B m is a Kronecker product of two vectors, a dimension of one vector is N 1 , a dimension of the other vector is N 2 , a dimension of B m is N 1 N 2 , and each antenna panel has N 1 antenna port pairs in a first dimension and N 2 antenna port pairs in a second dimension.

14. The communications apparatus according to claim 12 , wherein

A m,x,i l =a m,x,i l p m,x,i l , wherein

a m,x,i l represents an amplitude coefficient, and p m,x,i l represents a phase coefficient.

15. The communications apparatus according to claim 14 , wherein

A m,2,i l =φ m A m,1,i l , wherein

φ m represents a polarization phase factor, and the first indication information is used to indicate B m , φ m , a m,1,i l , and p m,1,i l .

16. The communications apparatus according to claim 12 , wherein

A m,x,i l =c i l a m,x,i l p m,x,i l , wherein

a m,x,i l represents an amplitude coefficient, p m,x,i l represents a phase coefficient, and c i l represents an antenna panel phase factor.

17. The communications apparatus according to claim 16 , wherein c 1 l =1, and the first indication information is used to indicate B m , c i l (i≠1), a m,x,i l , and p m,x,i l .

18. The communications apparatus according to claim 16 , wherein c i 1 is equal to 0 or 1, and the first indication information is used to indicate B m , c i l , a m,x,i l , and p m,x,i l .

19. A non-transitory computer-readable storage medium, comprising a computer program, which when executed on a computer, causes the computer to perform a method comprising:

generating, by a terminal device, first indication information, wherein the first indication information is used to indicate a precoding matrix, the precoding matrix is applied to at least one antenna panel and comprises at least one precoding vector, each precoding vector comprising at least one subvector, each subvector corresponds to an antenna port on the antenna panel and comprises two polarization vectors, and each polarization vector is generated by performing a weighted combination on a plurality of basis vectors; and

sending the first indication information,

wherein the two polarization vectors comprise a first polarization vector and a second polarization vector that respectively correspond to two polarization directions of a dual polarization antenna.

20. The medium according to claim 19 , wherein

the precoding matrix is:

1

α

⁡

[

P

1

P

2

…

P

r

]

,

wherein

P l is the precoding vector, r≥l≥1, r≥1, r represents a quantity of data layers,

1

α

is a normalized coefficient, and

0

<

1

α

≤

1

;

the precoding vector P l is:

[

S

1

l

S

2

l

⋮

S

N

g

l

]

,

wherein

S i l is a subvector of the precoding vector P l , N g ≥i≥1, N g ≥1, and N g is a quantity of the at least one antenna panel; and

the subvector S i l is:

[

Q

1

,

i

l

Q

2

,

i

l

]

,

wherein

Q x,i l is a polarization vector of the subvector S i l , and x is equal to 1 or 2.