Explanation
According to the Beamforming techniques for massive MIMO systems in 5G, these statements are correct about downlink beamforming. Beamforming is a technique that uses multiple antennas to steer the transmitted signal toward the intended user or direction. Static beams are used for broadcast channels, such as MIB and SIB, which are transmitted to all UEs in a cell. Dynamic beams are used for traffic channels, such as PDSCH and PDCCH, which are transmitted to specific UEs based on their channel conditions and locations. Both broadcast channels and traffic channels support beamforming, but with different beamforming methods and performance requirements.