Beamforming: Techniques and Implementations for Source Signal Reconstruction from Sensor Arrays

Beamforming is the process of reconstructing a source signal from a sensor array through two primary approaches: (1) amplifying the contributions from desired sources and (2) suppressing interfering signals. Classical beamforming requires prior knowledge of the direction of arrival (DOA) of the target signal. Blind beamforming attempts to recover the source signal without DOA information, employing statistical or optimization-based methods. The core principle involves applying weighted summation to array element outputs, "steering" the antenna beam toward a specific direction to maximize the output power of the desired signal—this optimal steering angle provides the DOA estimate. Although individual antenna elements have omnidirectional radiation patterns, weighted combination of their outputs concentrates gain in a specific direction, effectively forming a directional "beam."