Compensation techniques for group delay effects in transmit beamforming radio communication

Abstract

In a wireless communication device, transmit weights are iteratively processed to compensate for any group delay caused by receive synchronization in the receive device. A transmit matrix of weights is computed from signals transmitted by a second communication device and received at a plurality of antennas of the first communication device. The transmit matrix processing includes normalizing a transmit weight vector with respect to a mode of the transmit weight associated with one of the plurality of antennas.

1 . A MIMO radio communication device comprising: 
 a plurality of antennas;    a radio transceiver coupled to the plurality of antennas, the radio transceiver configured to upconvert a plurality of transmit signals for simultaneous transmission via the plurality of antennas, and to downconvert a plurality of signals simultaneously received at the plurality of antennas to produce a plurality of received signals; and    a baseband signal processor coupled to the radio transceiver, configured to compute receive weights from the signals received at the plurality of antennas, to compute transmit weights by computing an intermediate vector equal to a conjugate of a receive weight vector formed by the receive weights divided by the norm of the conjugate of the receive weight vector, and to process the transmit weights by dividing the intermediate vector by an element of the intermediate vector corresponding to one of the plurality of antennas of the first communication device.