Principles of Transmit Beamforming
The basic principle of transmit beamforming is to maximize the received Signal to
Noise Ratio (SNR) at the intended destination. It is a general signal processing technique
used to control the directionality of the transmission of a signal on a transducer array. A
transmit beamformer itself is a spatial filter that operates on the output of an array of
sensors in order to enhance the amplitude of a coherent wavefront relative to background
noise and directional interference.


Energy Gains of Transmit Beamforming
The question of how is directional transmission achieved is of particular importance. In
beamforming, each user’s signal is multiplied with complex weights that adjust the
magnitude and phase of the signal to and from each antenna. This causes the output from
the array of antennas to form a transmit beam in the desired direction and minimizes the
output in other directions. This directionality provides a strong energy gain observed at
the destination.