Signal receiving and sending method and communications apparatus

1. A method for wireless communications, comprising:

receiving first indication information on a first component carrier (CC), wherein the first indication information indicates a bandwidth part (BWP) for transmitting a downlink signal and a second CC to which the BWP belongs;

determining a first mapping relationship based on the second CC and the BWP, wherein the first mapping relationship indicates a one-to-one correspondence between at least one transmission configuration indicator (TCI) state and at least one TCI value;

determining a TCI state based on the first mapping relationship and a received TCI value;

determining, based on the TCI state, a receive beam for receiving the downlink signal; and

receiving the downlink signal in the BWP on the second CC by using the receive beam.

2. The method according to claim 1 , wherein the determining the first mapping relationship comprises:

receiving a plurality of media access control (MAC) control elements (CEs); and

determining, based on the second CC and the BWP, a mapping relationship indicated by using a first MAC CE in the plurality of MAC CEs as the first mapping relationship, wherein an identifier of a CC indicated by the first MAC CE is same as an identifier of the second CC indicated by using the first indication information, and an identifier of a BWP indicated by the first MAC CE is same as an identifier of the BWP indicated by using the first indication information.

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

before determining the first mapping relationship, receiving second indication information, wherein the second indication information indicates to determine the first mapping relationship based on the second CC and the BWP.

4. The method according to claim 1 , wherein the downlink signal is transmitted on a physical downlink shared channel, and the first indication information is comprised in downlink control information (DCI).

5. The method according to claim 4 , wherein the DCI further comprises the received TCI value.

6. A method for wireless communications, comprising:

sending first indication information on a first component carrier (CC), wherein the first indication information indicates a bandwidth part (BWP) for transmitting a downlink signal and a second CC to which the BWP belongs;

determining a first mapping relationship based on the second CC and the BWP, wherein the first mapping relationship indicates a one-to-one correspondence between at least one transmission configuration indicator (TCI) state and at least one TCI value;

determining a TCI state based on the first mapping relationship and a TCI value;

determining, based on the TCI state, a transmit beam for sending the downlink signal; and

sending the downlink signal in the BWP on the second CC by using the transmit beam.

7. The method according to claim 6 , wherein the method further comprises:

sending a plurality of media access control (MAC) control elements (CEs), wherein the plurality of MAC CEs as the first mapping relationship comprise a first MAC CE, an identifier of a CC indicated by the first MAC CE is same as an identifier of the second CC indicated by using the first indication information, and an identifier of a BWP indicated by the first MAC CE is same as an identifier of the BWP indicated by using the first indication information.

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

before determining the first mapping relationship, sending second indication information, wherein the second indication information indicates to determine the first mapping relationship based on the second CC and the BWP.

9. The method according to claim 6 , wherein the downlink signal is transmitted on a physical downlink shared channel, and the first indication information is comprised in downlink control information (DCI).

10. The method according to claim 9 , wherein the DCI further comprises the TCI value.

11. A communications apparatus, comprising:

at least one processor

coupled to one or more memories that store programming instructions for execution by the at least one processor to:

receive first indication information on a first component carrier (CC), wherein the first indication information indicates a bandwidth part (BWP) for transmitting a downlink signal and a second CC to which the BWP belongs; and

determine a first mapping relationship based on the second CC and the BWP, wherein the first mapping relationship indicates a one-to-one correspondence between at least one transmission configuration indicator (TCI) state and at least one TCI value, wherein

determine a TCI state based on the first mapping relationship and a received TCI value;

determine, based on the TCI state, a receive beam for receiving the downlink signal; and

receive the downlink signal in the BWP on the second CC by using the receive beam.

12. The communications apparatus according to claim 11 , wherein the programming instructions are for execution by the at least one processor to receive a plurality of media access control (MAC) control elements (CEs); and

determine, based on the second CC and the BWP, a mapping relationship indicated by using a first MAC CE in the plurality of MAC CEs as the first mapping relationship, wherein an identifier of a CC indicated by the first MAC CE is same as an identifier of the second CC indicated by using the first indication information, and an identifier of a BWP indicated by the first MAC CE is same as an identifier of the BWP indicated by using the first indication information.

13. The communications apparatus according to claim 11 , wherein the programming instructions are for execution by the at least one processor to receive second indication information, and the second indication information indicates to determine the first mapping relationship based on the second CC and the BWP.

14. The communications apparatus according to claim 11 , wherein the downlink signal is transmitted on a physical downlink shared channel, and the first indication information is comprised in downlink control information (DCI).

15. A communications apparatus, comprising:

at least one processor

coupled to one or more memories that store programming instructions for execution by the at least one processor to:

send first indication information on a first component carrier (CC), wherein the first indication information indicates a bandwidth part (BWP) for transmitting a downlink signal and a second CC to which the BWP belongs;

determine a first mapping relationship based on the second CC and the BWP, wherein the first mapping relationship indicates a one-to-one correspondence between at least one transmission configuration indicator (TCI) state and at least one TCI value;

determine a TCI state based on the first mapping relationship and a TCI value;

determine, based on the TCI state, a transmit beam for sending the downlink signal; and

send the downlink signal in the BWP on the second CC by using the transmit beam.

16. The communications apparatus according to claim 15 , wherein the programming instructions are for execution by the at least one processor to send a plurality of media access control (MAC) control elements (CEs), the plurality of MAC CEs as the first mapping relationship comprise a first MAC CE, an identifier of a CC indicated by the first MAC CE is same as an identifier of the second CC indicated by using the first indication information, and an identifier of a BWP indicated by the first MAC CE is same as an identifier of the BWP indicated by using the first indication information.

17. The communications apparatus according to claim 15 , wherein the programming instructions are for execution by the at least one processor to send second indication information, wherein the second indication information indicates to determine the first mapping relationship based on the second CC and the BWP.

18. The communications apparatus according to claim 15 , wherein the downlink signal is transmitted on a physical downlink shared channel, and the first indication information is comprised in downlink control information (DCI).

19. The communications apparatus according to claim 18 , wherein the DCI further comprises the TCI value.

20. The communications apparatus according to claim 14 , wherein the DCI further comprises the received TCI value.