Method and apparatus for transmiting and receiving synchronization signal in new radio vehicle to everything system

A wireless user device comprising:

• at least one antenna;
• at least one processor;
• and
• a memory storing instructions that, when executed by the at least one processor, cause the wireless user device to:
• determine a global navigation satellite system (GNSS) as a synchronization reference source associated with a sidelink synchronization;
• determine a slot number for sidelink communication, based on:
• the GNSS being the synchronization reference source associated with a sidelink synchronization;
• and
• a modulo operation associated with a subcarrier spacing index for sidelink;
• transmit, based on the slot number, a sidelink synchronization signal from the wireless user device to a second wireless user device, and wherein the instructions, when executed by the at least one processor, cause the wireless user device to determine the slot number based on Floor((Tcurrent−Tref−OffsetDFN)*2μ)mod(10*2μ), where Tcurrent is a current Coordinated Universal Time (UTC) time obtained from the GNSS, Tref is a reference UTC time, OffsetDFN is, if configured, a direct frame number (DFN) offset value associated with a sidelink DEN or, if not configured, zero, and wherein μ is the subcarrier spacing index for sidelink.