Both methods and apparatus for setting up millimeter wave (mmW) link communications include initial selection of candidate mmW Base Station (mB) and configuration of mmW acquisition resources and procedures, with assistance of cellular network. . Another method transmits mmW acquisition beacons, processes the mmW acquisition beacons to achieve mmW beam alignment and timing synchronization, and reports uplink (UL) over the cellular or mmW link. In an example, a mmW wireless transmit / receive unit (WTRU) transmits millimeter-wave (mmW) WTRU (mmW WTRU) information to a base station via a cellular system and includes a candidate mmW base station (mmW acquisition start timing information) that includes mmW acquisition start timing information. Receive a candidate list of mB) and calculate correlations around the received mmW acquisition start timing information for mB in the candidate list. The mmW WTRU performs sliding window correlation using signature sequences corresponding to mBs and beams in the candidate list.