A method and apparatus for antenna-array size adaptation at a BS include performing an initial beam refinement procedure using a plurality of antenna arrays with one or more devices, transmitting a plurality of beams using a plurality of antenna configurations to the one or more devices as part of an enhanced beam training procedure, wherein each antenna configuration includes a different subset of the plurality of antenna arrays used to transmit a different beam of the plurality of beams, receiving a plurality of feedback messages from the one or more devices associated with the plurality of beams transmitted using the plurality of antenna configurations, selecting an antenna configuration including a subset of the plurality of antenna arrays based on the plurality of feedback messages from the one or more devices, and communicating with the one or more devices using the selected subset of the plurality of antenna arrays.