Method executed by user equipment, and user equipment

A user equipment, comprising:

• at least one processor;
• and
• at least one non-transitory computer-readable medium coupled to the at least one processor and storing one or more computer-executable instructions that, when executed by the at least one processor, cause the user equipment to:
• receive system information from a base station, the system information including time division duplexing (TDD) configuration information;
• select a synchronization source from a plurality of sources, including the base station and another user equipment, based on a priority criterion, wherein a priority of the base station is higher than a priority of the other user equipment;
• transmit sidelink communication system information, including sidelink TDD configuration information, based on the synchronization source;
• and
• perform a sidelink communication based on the synchronization source, wherein:
• the sidelink communication system information further includes indication information indicating the synchronization source selected by the user equipment, and
• the indication information is indicated by at least one of an indication field in the sidelink communication system information, physical sidelink broadcast channel (PSBCH) scrambling or generation of scrambling sequences, and demodulation reference signal (DMRS) sequences for a PSBCH channel estimation.