Beam indication method and apparatus

1. A beam indication method, comprising:

determining, by a terminal device in a non-terrestrial network (NTN) system, first random access information associated with a first synchronization broadcast block (SSB) and a beam parameter that identifies a satellite beam from a plurality of satellite beams supported by the NTN system, wherein the plurality of satellite beams use the same first SSB, the plurality of satellite beams are distinguished by beam parameters, a total quantity of satellite beams supported by the NTN system is larger than a total quantity of SSBs supported by the NTN system, and the beam parameter that identifies the satellite beam comprises an attribute of a Doppler offset value or an attribute of a Doppler compensation value; and

sending, by the terminal device, a preamble to a satellite based on the first random access information.

2. The method according to claim 1 , wherein the attribute of the Doppler offset value is positive or negative.

3. The method according to claim 1 , further comprising obtaining the attribute of the Doppler offset value, wherein obtaining the attribute of the Doppler offset value comprises:

detecting, by the terminal device, the attribute of the Doppler offset value; or

receiving, by the terminal device, first information from the satellite, wherein the first information indicates the attribute of the Doppler offset value, and determining, by the terminal device, the attribute of the Doppler offset value based on the first information.

4. The method according to claim 1 , wherein the beam parameter of the satellite beam comprises a first index number corresponding to the satellite beam, and the first index number corresponding to the satellite beam is associated with the first random access information; and

the method further comprises: receiving, by the terminal device, the first index number from the satellite.

5. The method according to claim 1 , wherein the attribute of the Doppler compensation value is positive or negative; and

the method further comprises:

receiving, by the terminal device and from the satellite, the attribute of the Doppler compensation value corresponding to the satellite beam.

6. The method according to claim 1 , wherein the determining, by a terminal device, first random access information associated with a first SSB and associated with a beam parameter of a satellite beam comprises:

determining, by the terminal device, second random access information associated with the first SSB, wherein the second random access information comprises the first random access information; and

determining, by the terminal device, the first random access information in the second random access information and associated with the beam parameter of the satellite beam.

7. The method according to claim 6 , wherein:

the second random access information comprises the first random access information and third random access information, and

an intersection set of the first random access information and the third random access information is empty.

8. The method according to claim 6 , wherein the second random access information comprises a subset of the first random access information and a subset of third random access information, and an intersection set of the first random access information and the third random access information is empty.

9. The method according to claim 1 , wherein the first random access information comprises at least one of a random access resource or the preamble.

10. The method according to claim 1 , wherein:

the attribute of the Doppler offset value comprises a Doppler offset value of a downlink signal sent by the satellite, a Doppler offset value of the satellite beam, or a Doppler offset value of the first SSB, and

the attribute of the Doppler compensation value comprises a Doppler pre-compensation value or a value related to the Doppler pre-compensation value.

11. An apparatus in a non-terrestrial network (NTN) system, comprising:

at least one processor; and

one or more memories including computer-executable instructions that, when executed by the at least one processor, cause the apparatus to:

determine first random access information associated with a first synchronization broadcast block (SSB) and a beam parameter that identifies a satellite beam from a plurality of satellite beams supported by the NTN system, wherein the plurality of satellite beams use the same first SSB, the plurality of satellite beams are distinguished by beam parameters, a total quantity of satellite beams supported by the NTN system is larger than a total quantity of SSBs supported by the NTN system, and the beam parameter that identifies the satellite beam comprises an attribute of a Doppler offset value or an attribute of a Doppler compensation value; and

send a preamble to a satellite based on the first random access information.

12. The apparatus according to claim 11 , wherein the attribute of the Doppler offset value is positive or negative.

13. The apparatus according to claim 11 , wherein the computer-executable instructions, when executed by the at least one processor, further cause the apparatus to obtain the attribute of the Doppler offset value by operation comprising:

detecting the attribute of the Doppler offset value; or

receiving first information from the satellite, wherein the first information indicates the attribute of the Doppler offset value, and determining the attribute of the Doppler offset value based on the first information.

14. The apparatus according to claim 11 , wherein the beam parameter of the satellite beam comprises a first index number corresponding to the satellite beam, and the first index number corresponding to the satellite beam is associated with the first random access information, and wherein the computer-executable instructions, when executed by the at least one processor, further cause the apparatus to:

receive the first index number from the satellite.

15. The apparatus according to claim 11 , wherein the attribute of the Doppler compensation value is positive or negative, and wherein the computer-executable instructions, when executed by the at least one processor, further cause the apparatus to:

receive the attribute of the Doppler compensation value corresponding to the satellite beam from the satellite.

16. The apparatus according to claim 11 , wherein the computer-executable instructions, when executed by the at least one processor, further cause the apparatus to:

determine second random access information associated with the first SSB, wherein the second random access information comprises the first random access information; and

determine the first random access information that is in the second random access information and associated with the beam parameter of the satellite beam.

17. The apparatus according to claim 16 , wherein the second random access information comprises the first random access information and third random access information, and an intersection set of the first random access information and the third random access information is empty.

18. The apparatus according to claim 16 , wherein the second random access information comprises a subset of the first random access information and a subset of third random access information, and an intersection set of the first random access information and the third random access information is empty.

19. The apparatus according to claim 11 , wherein the first random access information comprises at least one of a random access resource or the preamble.

20. A beam indication method, comprising:

determining, by a terminal device in a non-terrestrial network (NTN) system, first random access information associated with a first synchronization broadcast block (SSB) and a beam parameter that identifies a satellite beam from a plurality of satellite beams supported by the NTN system, wherein the plurality of satellite beams use the same first SSB, the plurality of satellite beams are distinguished by beam parameters, a total quantity of satellite beams supported by the NTN system is larger than a total quantity of SSBs supported by the NTN system, and the beam parameter that identifies the satellite beam comprises an attribute of a Doppler offset value or an attribute of a Doppler compensation value;

sending, by the terminal device, a preamble to a satellite based on the first random access information;

receiving, by the satellite, the preamble from the terminal device;

determining, by the satellite, the first random access information; and

determining, by the satellite, the first SSB and the beam parameter that identifies the satellite beam that are associated with the first random access information.

21. The method according to claim 20 , further comprising: performing, by the satellite, sweeping of a plurality of beams simultaneously.