Reconfigurable massive MIMO array system for energy efficient communications

A radio interface in a wireless communication device, comprising:

• a plurality of radio frequency, RF, branches;
• an antenna array having a plurality of antenna elements, each antenna element of the antenna array being in electrical communication with an RF branch;
• a plurality of switches, each switch configured to selectively affect a mutual coupling between at least two antenna elements of the antenna array;
• and
• processing circuitry in communication with the plurality of switches, the processing circuitry configured to, for a beam direction:
• one of activate and deactivate each RF branch based at least in part on the beam direction and at least one power constraint, one of activating and deactivating each RF branch including activating a broadside array of the antenna array and deactivating at least one RF branch adjacent to the broadside array;
• and
• configure at least one switch of the plurality of switches to selectively affect a mutual coupling between at least two antenna elements of the antenna array that are in electrical communication with deactivated RF branches, the configuring being based at least in part on the beam direction, configuring the at least one switch including selectively affecting the mutual coupling between at least two antenna elements of at least one deactivated adjacent RF branch to select one of an azimuth direction and an elevation direction of a beam of the activated broadside array.