Patent attributes
A wireless transmit/receive unit (WTRU) may receive a configuration message from a first base station including correspondence information regarding a plurality of beam reference signals, the correspondence information including information regarding designation of at least one set of physical random access channel (PRACH) resources for each of the plurality of beam reference signals. The WTRU may measure the plurality of beam reference signals transmitted from a second base station and select a beam reference signal from among the plurality of measured beam reference signals. The WTRU may determine a set of PRACH resources for the selected beam reference signal based on the information regarding designation of at least one set of PRACH resources for each of the plurality of measured beam reference signals included in the correspondence information. The WTRU may transmit, to the second base station, a PRACH transmission using at least one PRACH resource of the determined set.