Systems, methods, and instrumentalities are for identifying, determining, or selecting one or more numerologies in a wireless system. The numerologies may include one or more of a subcarrier spacing, a transmission duration, a symbol duration, a number of symbols, or a cyclic prefix (CP) size. The WTRU may send an access request indicating the identified, determined, or selected one or more numerologies. The access request may be a random access channel (RACH) request or a scheduling request (SR). The WTRU may monitor one or more search spaces for one or more physical control channels. The search spaces may be monitored based on an identified, determined, or selected one or more numerologies. Within one of the search spaces, the WTRU may receive and successfully decode a physical control channel. The WTRU may transmit data based on the numerology associated with the search space in which the physical channel was successfully decoded.