A method and apparatus for determining Physical Random Access Channel (PRACH) resources and using beams are disclosed herein. In an example, a wireless transmit/receive unit (WTRU) may measure a plurality of beam reference signals transmitted from a base station. Further, the WTRU may select a beam reference signal from among the plurality of measured beam reference signals. Also, the WTRU may receive a configuration message from the base station that includes correspondence information regarding the plurality of beam reference signals, wherein the correspondence information designates at least one set of PRACH resources for each of the plurality of beam reference signals. In addition, the WTRU may determine a set of PRACH resources designated for the selected beam reference signal based on the received correspondence information. Moreover, the WTRU may transmit a PRACH signal using at least one PRACH resource of the determined set of PRACH resources.