A method and apparatus for improving and performing mmW beam tracking is disclosed. Localization methods to improve prediction of the position of a WTRU are described, which may allow a millimeter wave base station (mB) to appropriately select a modified beam and to perform more efficient handover. WTRUs may report directional signal strength measurements to mBs, which may then be used to generate a directional radio environment map (DREM) for use in identifying secondary links to use when a primary link fails. Additional localization techniques using internal/external information for prediction are described. Historical data use and the use of data obtained from mB-mB cooperation including feedback information and reference signaling information are also described. Methods for beam tracking for directional relays and initial beam training optimization are described as well. Finally, WTRU localization precision improvement, beamwidth adaptation, and assisted beam tracking and handover methods are also described.