Precoding method and communication apparatus

1 . A method, comprising:

receiving, by a terminal device from an access network device, a first reference signal that is precoded using a first precoding matrix;

sending, by the terminal device to the access network device, first information, wherein the first information is determined by the terminal device based on a measurement result of the first reference signal, and the first information determines a target precoding matrix; and

receiving, by the terminal device from the access network device, information precoded using the target precoding matrix;

wherein the first precoding matrix at a 1 st moment is a basic precoding matrix determined based on a first channel, the first channel is a channel between the access network device and a target reference point, and the terminal device is located in an area range corresponding to the target reference point; and

the first precoding matrix at an i th moment is a target precoding matrix at an (i−1) th moment, wherein i is an integer, and i≥2.

2 . The method according to claim 1 , wherein the first information comprises amplitude information of a target channel or phase information of the target channel or amplitude information and phase information of the target channel, the target channel being a channel between the terminal device and the access network device.

3 . The method according to claim 1 , wherein

a resolution corresponding to the first information is preconfigured.

4 . The method according to claim 1 , wherein

content of the first information at the 1 st moment comprises channel information of a target channel at the 1 st moment; and

content of the first information at an N th moment comprises differential information of the target channel at an (N−1) th moment and the N th moment, wherein

at the i th moment, the target channel is used to transmit the first reference signal corresponding to the i th moment, N is a positive integer, 1≤i≤N, and N≥2.

5 . The method according to claim 4 , wherein the method further comprises:

receiving, by the terminal device from the access network device, a second reference signal precoded using a third precoding matrix;

determining, by the terminal device, second information based on the measurement result of the first reference signal and a measurement result of the second reference signal, wherein the second information indicates the first reference signal; and

sending, by the terminal device to the access network device, the second information indicating that the first precoding matrix is used for data transmission.

6 . The method according to claim 1 , further comprising:

determining, by the terminal device, a resolution corresponding to the first information; and

sending, by the terminal device to the access network device, the resolution corresponding to the first information.

7 . The method according to claim 1 , further comprising:

obtaining, by the terminal device, indication information from the access network device, wherein the indication information indicates a resolution corresponding to the first information.

8 . A method comprising:

sending, by an access network device to a terminal device, a first reference signal that is precoded using a first precoding matrix;

obtaining, by the access network device from the terminal device, first information, wherein the first information is based on a measurement result of the first reference signal;

determining, by the access network device, a second precoding matrix based on the first information;

determining, by the access network device, a target precoding matrix based on the first precoding matrix and the second precoding matrix; and

precoding, by the access network device, to-be-sent information using the target precoding matrix;

wherein the first precoding matrix at a 1 st moment is a basic precoding matrix determined based on a first channel, the first channel is a channel between the access network device and a target reference point, and the terminal device is located in an area range corresponding to the target reference point; and

wherein the first precoding matrix at an i th moment is a target precoding matrix at an (i−1) th moment, wherein i is an integer, and i≥2.

9 . The method according to claim 8 , wherein the method further comprises:

obtaining, by the access network device, location information, wherein the location information comprises at least one of following: information about relative locations of the access network device and a target reference point, or a geographical location of the target reference point, and wherein the terminal device is located in an area range corresponding to the target reference point;

determining, by the access network device, channel information of a first channel based on the location information, wherein the first channel is a channel between the access network device and the target reference point; and

determining, by the access network device, the first precoding matrix based on the channel information of the first channel.

10 . The method according to claim 8 , wherein the first information comprises amplitude information of a target channel or phase information of the target channel or amplitude information and phase information of the target channel, and the target channel is a channel between the access network device and the terminal device.

11 . The method according to claim 8 , wherein

a resolution corresponding to the first information is preconfigured.

12 . The method according to claim 8 , wherein,

determining, by the access network device, the second precoding matrix based on the first information comprises:

determining, by the access network device, the second precoding matrix at an N th moment based on content of the first information at the N th moment, the content comprising differential information of a target channel at the N th moment and an (N−1) th moment, wherein at the i th moment, the target channel is used to transmit the first reference signal corresponding to the i th moment, N is an integer, 1≤i≤N, N≥2, and the target channel is a channel between the access network device and the terminal device;

determining, by the access network device, the target precoding matrix based on the first precoding matrix and the second precoding matrix comprises:

determining, by the access network device, the target precoding matrix at the N th moment based on the first precoding matrix at the N th moment and the second precoding matrix at the N th moment; and

precoding, by the access network device, the to-be-sent information using the target precoding matrix comprises:

precoding, by the access network device, the to-be-sent information using the target precoding matrix at the N th moment.

13 . The method according to claim 12 , wherein the method further comprises:

sending, by the access network device, a second reference signal that is precoded using a third precoding matrix;

obtaining, by the access network device, second information, wherein the second information is based on the measurement result of the first reference signal and a measurement result of the second reference signal, and indicates the first reference signal; and

determining, by the access network device based on the second information, that the first precoding matrix corresponding to the first reference signal is used for data transmission.

14 . The method according to claim 8 , further comprising:

obtaining, by the access network device from the terminal device, a resolution corresponding to the first information.

15 . The method according to claim 8 , further comprising:

determining, by the access network device, a resolution corresponding to the first information; and

sending, by the access network device, indication information to the terminal device, wherein the indication information indicates the resolution corresponding to the first information.

16 . An apparatus, comprising:

at least one processor; and

memory storing instructions that are executable by the at least one processor, wherein executing the instructions causes the apparatus to:

receive, from an access network device, a first reference signal that is precoded using a first precoding matrix;

send, to the access network device, first information, wherein the first information is determined by the apparatus based on a measurement result of the first reference signal, and the first information determines a target precoding matrix; and

receive, from the access network device, information precoded using the target precoding matrix;

wherein the first precoding matrix at a 1 st moment is a basic precoding matrix determined based on a first channel, the first channel is a channel between the access network device and a target reference point, and the apparatus is located in an area range corresponding to the target reference point; and

the first precoding matrix at an i th moment is a target precoding matrix at an (i−1) th moment, wherein i is an integer, and i≥2.

17 . The apparatus according to claim 16 , wherein the first information comprises amplitude information of a target channel or phase information of the target channel or amplitude information and phase information of the target channel, the target channel being a channel between the apparatus and the access network device.

18 . The apparatus according to claim 16 , wherein a resolution corresponding to the first information is preconfigured.

19 . The apparatus according to claim 16 , wherein:

content of the first information at the 1 st moment comprises channel information of a target channel at the 1 st moment; and

content of the first information at an N th moment comprises differential information of the target channel at an (N−1) th moment and the N th moment, wherein

at the i th moment, the target channel is used to transmit the first reference signal corresponding to the i th moment, N is a positive integer, 1≤i≤N, and N≥2.

20 . The apparatus according to claim 19 , wherein executing the instructions causes the apparatus to:

receive, from the access network device, a second reference signal precoded using a third precoding matrix;

determine second information based on the measurement result of the first reference signal and a measurement result of the second reference signal, wherein the second information indicates the first reference signal; and

send, to the access network device, the second information indicating that the first precoding matrix is used for data transmission.