LTE: How Beam forming works when it is needed and possible variations if possible ?

Answer 1

I am new to this concept But this two links describes about this
http://www.teletopix.org/4g-lte/visualization-of-beam-forming-in-lte/

and white paper
http://cdn.rohde-schwarz.com/dl_downloads/dl_application/application_notes/1ma186/1MA186_0e_LTE_transmission_modes_and_beamforming.pdf