Systems and methods for radio frequency calibration exploiting channel reciprocity in distributed input distributed output wireless communications

A method implemented within a multiple antenna system (MAS) with multiuser (MU) transmissions (“MU-MAS”) comprising:

• forming wireless connections between a plurality of user equipment devices (UEs), a plurality of wireless base transceiver base stations (BTSs), a centralized processor (CP), and/or a plurality of beacon stations;
• estimating uplink (UL) channel state information (CSI) at the one or more BTSs and/or the centralized processor (CP) from UL signaling;
• transmitting a plurality of training signals between the BTSs and the beacon stations;
• processing the plurality of training signals at one of more of the plurality of BTSs, the CP, and/or one or more beacon stations to estimate a plurality of RF calibration coefficients;
• preconditioning a matrix of UL CSI and obtaining a matrix of downlink (DL) CSI using the plurality of RF calibration coefficients by one or more of the plurality of BTSs, the CP, and/or one or more beacon stations;
• precoding radio signals using use the DL CSI by one or more of the plurality of BTSs, the CP, and/or one or more beacon stations to produce precoded radio signals;
• simultaneously transmitting the precoded radio signals from the plurality of BTSs, the precoding to cause deliberate radio frequency interference to create concurrent, non-interfering enclosed shapes in space of coherent wireless signals around one or more antennas of one or more of the UEs;
• and
• adapting the size of the enclosed shapes in space by the CP by selecting different subsets of the plurality of BTSs.