Tracking area update method, broadcast message transmission method, and communications apparatus

A broadcast message transmission method, comprising:

• determining, by a satellite device, that coverage of a beam belongs to at least two tracking areas (TAs);
• and
• periodically sending, by the satellite device, a broadcast message using the beam,
• wherein the broadcast message alternately carries tracking area codes (TACs) corresponding to one or more TAs of the at least two TAs.

A communications apparatus, comprising:

• at least one processor;
• and
• at least one non-transitory memory coupled to the at least one processor and configured to store instructions that, when executed by the at least one processor, cause the communications apparatus to:
• receive a broadcast message periodically sent by a satellite device, wherein the broadcast message alternately carries tracking area codes (TACs) corresponding to one or more tracking areas (TAs) of at least two TAs, and wherein coverage of a beam of the satellite device belongs to the at least two TAs;
• record, when detecting for a first time that a TA corresponding to a TAC in a current broadcast message received in a current period does not belong to a first TA list, the TA in a second TA list, wherein the first TA list comprises one or more first TAs configured to page the communications apparatus, and wherein the second TA list is configured to store a detected TA that is not in the first TA list;
• continue detecting a subsequent broadcast message;
• and
• determine, based on a subsequent TAC in the subsequent broadcast message, whether to initiate a TA update procedure to update the first TA list.

A communications apparatus, comprising:

• at least one processor;
• and
• at least one memory coupled to the at least one processor and configured to store instructions that, when executed by the at least one processor, cause the communications apparatus to:
• determine that coverage of a beam belongs to at least two tracking areas (TAs);
• and
• periodically output a broadcast message using the beam,
• wherein the broadcast message alternately carries tracking area codes (TACs) corresponding to one or more TAs of the at least two TAs.