Most mobile masts, in busy areas, are arranged to receive and send data within a 120 degree sector. These masts will have 3 aerials mounted equally around the mast. This is great when the demand for the services are equally space throughout the area. Also this is the easiest way to manage the masts.

But there are a number of areas where spreading the signal equally over the sector makes little sense and the signal needs to be targeted. For example if the signal is designed to be send up and down a railway then a signal tuned to this direction only makes sense. Equally if in a FWA scenario, the 'target' is a small hamlet then it is a waste putting signal over some fields. This ideas here are static ways to ensure the signal is targeted at the highest demand.

Beamforming within 5G is a more dynamic feature that works with MIMO. The direction of the beam can change and react to the demand and / or track a user with a high demand.