To provide a method for establishing millimeter-wave link communication and a wireless transmission/reception unit (WTRU) for receiving support from a cellular network, including initial selection of a candidate mmW base station and configuration of mmW acquisition resources and procedure.SOLUTION: A method sends an mmW acquisition beacon, processes the mmW acquisition beacon to achieve mmW beam alignment and timing synchronization, and makes an uplink report via a cellular or an mmW link. An mmW wireless transmission/reception unit transmits millimeter-wave WTRU information to a base station through a cellular system, receives a candidate list of candidate mmW base stations including mmW acquisition start timing information, and calculates the correlation value of reception mmW acquisition start timing for mB in the candidate list. The mmW WTRU performs sliding window correlation using a signature sequence corresponding to the mB and beam in the candidate list.SELECTED DRAWING: Figure 3