Estimation of downlink transmission parameters in a radio communications system with an adaptive antenna array

A machine-readable medium having stored thereon data representing instructions which, when executed by a machine, cause the machine to perform operations comprising:

• receiving signals at an antenna array from a plurality of different locations;
• deriving characterizations of the spatial parameters of the received signals;
• receiving measurements of a plurality of different signals transmitted from the antenna array to a plurality of different locations;
• deriving characterizations of the spatial parameters of the transmitted signals from the received measurements;
• generating a transformation function for producing transmit spatial parameters based on measurements of received signals using the receive spatial parameter characterizations and the transmit spatial parameter characterizations.

An apparatus comprising:

• a transmitter to transmit a plurality of different signals to a plurality of different remote locations;
• a receiver to receive signals at an antenna array from a plurality of different locations, at least a portion of the received signals including measurements of at least a portion of the different transmitted signals;
• and
• a processor to derive characterizations of the spatial parameters of the received signals,
• to receive measurements of the transmitted signals,
• to derive characterizations of the spatial parameters of the transmitted signals from the received measurements, and
• to generate a transformation function for producing transmit spatial parameters based on measurements of received signals using the receive spatial parameter characterizations and the transmit spatial parameter characterizations.