beamforming

Beamforming is the art of aiming a radio beam without physically moving anything — by adjusting the timing (phase) and strength of the signal fed to each element of an antenna array. Imagine a row of people throwing stones into a pond on a precise stagger; the ripples reinforce into one tall wave heading exactly where the timing dictates. Your 5G phone and Wi-Fi 6 router do this thousands of times a second to point their signal straight at you.

Because the beam is steered in software, one base station can spin a focused spotlight toward each user in turn, reusing the same frequency for many people at once — the heart of massive MIMO. The same trick can sink a null (a dead zone) onto an interferer, dramatically boosting signal-to-noise. The catch is that it needs good knowledge of where the user is, which is why beamforming systems constantly probe the channel with reference signals.