A method performed by a wireless transmit/receive unit (WTRU) may include receiving a configuration message including timing information for monitoring at least a subset of a plurality of beams to receive a set of synchronization signals and receiving the set of synchronization signals based on the timing information. The received set of synchronization signals include a primary synchronization signal and a secondary synchronization signal. The method may include receiving a reference signal along with a physical broadcast channel (PBCH) transmission. The reference signal comprises a sequence that is derived from an index associated with one of the at least the subset of beams and associated with the received set of synchronization signals. The method may include transmitting a random access channel (RACH) transmission. The RACH transmission includes a preamble sequence corresponding to the one of the subset of the plurality of beams.