US-20260128787-A1 - METHOD AND APPARATUS FOR ACCESSING NON-TERRESTRIAL NETWORKS

Abstract

This disclosure provides a communication method for a radio access network and a core network, and an associated communication apparatus. A terminal device may determine a first reference point list, where the first reference point list includes points at which a plurality of beams are projected onto the ground; and determine a second beam based on the first reference point list and a movement direction of a first satellite. When an access beam is selected, the movement direction of the first satellite is considered, so that a beam switching problem in an access process caused by satellite movement can be avoided. A broadcast beam with a largest beam coverage area in the movement direction is selected based on a reference point in the first reference point list, to ensure smooth access.

Inventors

• Chuili Kong
• Hejia Luo
• Kexin LI
• Yu Wang
• Jun Wang

Assignees

• HUAWEI TECHNOLOGIES CO., LTD.

Dates

Publication Date

20260507

Application Date

20251229

Claims (20)

1. 1 . A communication method for accessing a non-terrestrial network (NTN), applied to a communication apparatus and comprising: determining a first reference point list, wherein the first reference point list comprises a plurality of first reference points, the first reference points are points within beam coverage areas of a plurality of first beams projected onto the ground, the plurality of first beams are in one-to-one correspondence with the plurality of first reference points, and the plurality of first reference points are at same relative positions within the beam coverage areas; and determining a second beam based on the first reference point list and a movement direction of a first satellite, wherein the second beam is one of the plurality of first beams, and the second beam is used for accessing the first satellite.
2. 2 . The method according to claim 1 , wherein the determining the first reference point list comprises: receiving the first reference point list from an access network device by using a broadcast message.
3. 3 . The method according to claim 1 , wherein the determining the first reference point list comprises: receiving a first beam direction list from an access network device by using a broadcast message, wherein the first beam direction list comprises directions of the plurality of first beams, and a direction, in the first beam direction list, of a first beam of the plurality of first beams indicates an elevation angle and an azimuth angle of the first beam; and determining the first reference point list based on the first beam direction list, wherein the directions of the plurality of first beams are in one-to-one correspondence with the plurality of first reference points.
4. 4 . The method according to claim 1 , wherein the determining the first reference point list comprises: receiving beam width information and beam index list information from an access network device by using a broadcast message, wherein the beam width information indicates a beam width of a first beam, of the plurality of first beams, from the first satellite; and determining the first reference point list based on the beam width information and the beam index list information.
5. 5 . The method according to claim 1 , wherein the determining the second beam based on the first reference point list and the movement direction of the first satellite comprises: determining a first vector set based on position information of the communication apparatus and ephemeris information of the first satellite, wherein the first vector set comprises a plurality of first vectors, an initial point of the first vector is a position of the communication apparatus, and an end point of the first vector is a second reference point; determining a first scalar set based on the first vector set and the movement direction of the first satellite, wherein the first scalar set comprises a plurality of first scalars, and the first scalar is a projection distance of the first vector in the movement direction of the first satellite; and determining the second beam based on the first scalar set.
6. 6 . The method according to claim 5 , wherein the second reference point is any reference point in the first reference point list, or the second reference point is any reference point in a second reference point list, the second reference point list is a subset or a universal set of the first reference point list, the second reference point list comprises the plurality of first reference points, and the first beams corresponding to the plurality of first reference points comprised in the second reference point list satisfy a reference signal received power (RSRP) threshold.
7. 7 . The method according to claim 6 , wherein when the second reference point is any reference point in the first reference point list, the determining the second beam based on the first scalar set comprises: determining a second scalar set based on the first scalar set, wherein the second scalar set is a subset or a universal set of the first scalar set, and beams corresponding to the plurality of first scalars comprised in the second scalar set satisfy the RSRP threshold; and determining a beam corresponding to a smallest first scalar in the plurality of first scalars in the second scalar set as the second beam.
8. 8 . A communication apparatus, comprising: a transceiver; and at least one processor coupled to one or more memories storing programming instructions, wherein the programming instructions are executed by the at least one processor to cause the communication apparatus to perform operations comprising: determining a first reference point list, wherein the first reference point list comprises a plurality of first reference points, the first reference points are points within beam coverage areas of a plurality of first beams projected onto the ground, the plurality of first beams are in one-to-one correspondence with the plurality of first reference points, and the plurality of first reference points are at same relative positions within the beam coverage areas; and determining a second beam based on the first reference point list and a movement direction of a first satellite, wherein the second beam is one of the plurality of first beams, and the second beam is used for accessing the first satellite.
9. 9 . The communication apparatus according to claim 8 , wherein the programming instructions are executed by the at least one processor to cause the communication apparatus to further perform operations comprising: receiving the first reference point list from an access network device by using a broadcast message.
10. 10 . The communication apparatus according to claim 8 , wherein the programming instructions are executed by the at least one processor to cause the communication apparatus to further perform operations comprising: receiving a first beam direction list from an access network device by using a broadcast message, wherein the first beam direction list comprises directions of the plurality of first beams, and a direction, in the first beam direction list, of a first beam in the first beam direction list indicates an elevation angle and an azimuth angle of the first beam; and determining the first reference point list based on the first beam direction list, wherein the directions of the plurality of first beams are in one-to-one correspondence with the plurality of first reference points.
11. 11 . The communication apparatus according to claim 8 , wherein the programming instructions are executed by the at least one processor to cause the communication apparatus to further perform operations comprising: receiving beam width information and beam index list information from an access network device by using a broadcast message, wherein the beam width information indicates a beam width of a first beam, of the plurality of first beams, from the first satellite; and determining the first reference point list based on the beam width information and the beam index list information.
12. 12 . The communication apparatus according to claim 8 , wherein the programming instructions are executed by the at least one processor to cause the communication apparatus to further perform operations comprising: determining a first vector set based on position information of the communication apparatus and ephemeris information of the first satellite, wherein the first vector set comprises a plurality of first vectors, an initial point of the first vector is a position of the communication apparatus, and an end point of the first vector is a second reference point; determining a first scalar set based on the first vector set and the movement direction of the first satellite, wherein the first scalar set comprises a plurality of first scalars, and the first scalar is a projection distance of the first vector in the movement direction of the first satellite; and determining the second beam based on the first scalar set.
13. 13 . The communication apparatus according to claim 12 , wherein the second reference point is any reference point in the first reference point list, or the second reference point is any reference point in a second reference point list, the second reference point list is a subset or a universal set of the first reference point list, the second reference point list comprises the plurality of first reference points, and the first beams corresponding to the plurality of first reference points comprised in the second reference point list satisfy a reference signal received power (RSRP) threshold.
14. 14 . The communication apparatus according to claim 13 , wherein when the second reference point is any reference point in the first reference point list, the programming instructions are executed by the at least one processor to cause the communication apparatus to further perform operations comprising: determining a second scalar set based on the first scalar set, wherein the second scalar set is a subset or a universal set of the first scalar set, and beams corresponding to the plurality of first scalars comprised in the second scalar set satisfy the RSRP threshold; and determining a beam corresponding to a smallest first scalar in the plurality of first scalars in the second scalar set as the second beam.
15. 15 . A non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions, when executed by at least one processor of a communication apparatus, cause the communication apparatus to perform operations comprising: determining a first reference point list, wherein the first reference point list comprises a plurality of first reference points, the first reference points are points within beam coverage areas of a plurality of first beams projected onto the ground, the plurality of first beams are in one-to-one correspondence with the plurality of first reference points, and the plurality of first reference points are at same relative positions within the beam coverage areas; and determining a second beam based on the first reference point list and a movement direction of a first satellite, wherein the second beam is one of the plurality of first beams, and the second beam is used for accessing the first satellite.
16. 16 . The non-transitory computer-readable storage medium storing computer instructions according to claim 15 , wherein the computer instructions are executed by the at least one processor to cause the communication apparatus to further perform operations comprising: receiving the first reference point list from an access network device by using a broadcast message.
17. 17 . The non-transitory computer-readable storage medium storing computer instructions according to claim 15 , wherein the computer instructions are executed by the at least one processor to cause the communication apparatus to further perform operations comprising: receiving a first beam direction list from an access network device by using a broadcast message, wherein the first beam direction list comprises directions of the plurality of first beams, and a direction, in the first beam direction list, of a first beam in the first beam direction list indicates an elevation angle and an azimuth angle of the first beam; and determining the first reference point list based on the first beam direction list, wherein the directions of the plurality of first beams are in one-to-one correspondence with the plurality of first reference points.
18. 18 . The non-transitory computer-readable storage medium storing computer instructions according to claim 15 , wherein the computer instructions are executed by the at least one processor to cause the communication apparatus to further perform operations comprising: receiving beam width information and beam index list information from an access network device by using a broadcast message, wherein the beam width information indicates a beam width of a first beam, of the plurality of first beams, from the first satellite; and determining the first reference point list based on the beam width information and the beam index list information.
19. 19 . The non-transitory computer-readable storage medium storing computer instructions according to claim 15 , wherein the computer instructions are executed by the at least one processor to cause the communication apparatus to further perform operations comprising: determining a first vector set based on position information of the communication apparatus and ephemeris information of the first satellite, wherein the first vector set comprises a plurality of first vectors, an initial point of the first vector is a position of the communication apparatus, and an end point of the first vector is a second reference point; determining a first scalar set based on the first vector set and the movement direction of the first satellite, wherein the first scalar set comprises a plurality of first scalars, and the first scalar is a projection distance of the first vector in the movement direction of the first satellite; and determining the second beam based on the first scalar set.
20. 20 . The non-transitory computer-readable storage medium storing computer instructions according to claim 19 , wherein the second reference point is any reference point in the first reference point list, or the second reference point is any reference point in a second reference point list, the second reference point list is a subset or a universal set of the first reference point list, the second reference point list comprises the plurality of first reference points, and the first beams corresponding to the plurality of first reference points comprised in the second reference point list satisfy a reference signal received power (RSRP) threshold.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of International Application No. PCT/CN2023/104414, filed on Jun. 30, 2023, the disclosure of which is hereby incorporated by reference in its entirety. TECHNICAL FIELD This disclosure relates to satellite networks, and more specifically, to a method for accessing a non-terrestrial network (NTN) and an associated communication apparatus. BACKGROUND A non-terrestrial network (NTN) like satellite communication has significant advantages such as global coverage, long-distance transmission, flexible networking, convenient deployment, and no limitation from geographical conditions, and has been widely applied to a plurality of fields such as maritime communication, positioning and navigation, disaster relief, scientific experiments, video broadcasting, and earth observation. A current new radio (NR) beam sweeping solution is not applicable to an NTN system. For an NTN communication system, when remaining service time of a beam corresponding to a synchronization signal block (SSB) selected by a terminal device (UE) is less than access time of the UE, in a UE access process, beam switching is caused by satellite movement, resulting in a UE access interruption. SUMMARY Embodiments of this disclosure provide a method for accessing an NTN and a communication apparatus, to ensure that a UE can select a proper beam and complete access under one beam, thereby avoiding beam switching in an access process and ensuring smooth access. According to a first aspect, a method for accessing an NTN is provided. The method may be performed by a terminal device, or may be performed by a chip or a circuit configured in the terminal device. This is not limited in this disclosure. The method includes: determining a first reference point list, where the first reference point list includes a plurality of first reference points, the first reference points are points within beam coverage areas of first beams projected onto the ground, the plurality of first beams are in one-to-one correspondence with the plurality of first reference points, and the plurality of first reference points are at same relative positions within the beam coverage areas; and determining a second beam based on the first reference point list and a movement direction of a first satellite, where the second beam is one of the plurality of first beams, and the second beam is used to access the satellite. In this technical solution, the terminal device may determine the first reference point list, where the first reference point list includes points at which a plurality of beams are projected onto the ground; and determine the second beam based on the first reference point list and the movement direction of the first satellite. It should be understood that when an access beam is selected, the movement direction of the first satellite is considered, so that a beam switching problem in an access process caused by satellite movement can be avoided, to ensure smooth access. With reference to the first aspect, in an implementation of the first aspect, the first reference point list is received from an access network device by using a broadcast message. In this technical solution, the terminal device may receive, by using the broadcast message, the first reference point list sent by the access network device. The broadcast message may be carried by using a SIB 19, or another system information block (SIB) message. This is not limited in this embodiment of this disclosure. With reference to the first aspect, in an implementation of the first aspect, a first beam direction list is received from an access network device by using a broadcast message, where the first beam direction list includes directions of the plurality of first beams, and the direction of the first beam indicates an elevation angle and an azimuth angle of the first beam; and the first reference point list is determined based on the first beam direction list, where the directions of the plurality of first beams are in one-to-one correspondence with the plurality of first reference points. This technical solution is another manner in which the terminal device determines the first reference point list. The access network device sends the first beam direction list to the terminal device. The first beam direction list indicates the directions of the plurality of beams. The terminal device may determine corresponding reference points based on the directions of the plurality of beams, to determine the first reference point list. According to this technical solution, the terminal device may select a broadcast beam with a largest beam coverage area in the movement direction based on a reference point in the first reference point list, to avoid the beam switching problem in the access process caused by the satellite movement, and ensure the smooth access. With reference to the first aspect, in an implementation of the first aspect, beam width info