Methods and an apparatus for performing synchronization in New Radio (NR) systems are disclosed. A frequency band may be determined and may correspond to a WTRU. On a condition that the operational frequency band is a lower frequency, a synchronization signal block (SSB) index may be implicitly. On a condition that the operational frequency band is a higher frequency, an SSB index may be determined based on a hybrid method which includes determining the SSB index using both an implicit and an explicit method. A configuration of actually transmitted SSBs may be determined using a multi-level two stage compressed indication where SSB groups are determined based on a coarse indicator and actually transmitted SSBs with the SSB groups are determined based on a fine indicator.