Patent ID: 8619886

Claim:
A method of mixed analog/digital beamforming in a wireless communication system, the wireless system having a plurality of transmit antennas and receive antennas and a plurality of analog front-ends connected to the plurality of transmit and receive antennas, at least two of the analog front-ends being connected to either the transmit antennas or the receive antennas, the method comprising determining transmit and receive analog beamforming coefficients and transmit and receive digital beamforming coefficients, the process of determining the analog and digital beamforming coefficients comprising: determining information representative of communication channels formed between a transmit antenna and a receive antenna of the plurality of antennas; defining a set of coefficients representing the transmit analog beamforming coefficients and the receive analog beamforming coefficients; determining a beamforming cost function using the information and the set of coefficients, the beamforming cost function taking into account the plurality of analog front-ends; computing an optimized set of coefficients by exploiting the beamforming cost function, the optimized set of coefficients comprising optimized transmit analog beamforming coefficients and optimized receive analog beamforming coefficients; deriving an estimate of the frequency responses of the communication channels using the determined information representative of communication channels; and deriving, for each communication channel, the transmit digital beamforming coefficients and receive digital beamforming coefficients using the estimated frequency responses and the optimized transmit and receive analog beamforming coefficients.