Next generation of mobile communication systems must support astounding data traffic increases, higher data rates and lower latency, among other requirements. All these requirements should be met while assuring energy efficiency for mobile devices and base stations. Most likely, the future 5G systems will include massive MIMO (Multiple Input Multiple Output) schemes with dozen or hundreds of antennas enabling beamforming while operating in the millimeter wave spectrum. As soon as the millimetric wave propagation difficulties are overcome, the full potential of massive MIMO structures can be tapped. This paper presents a transmission system with bi-dimensional antenna arrays, based on a double layer structure combining beamforming with a multi-branch power amplification that achieves simultaneously power efficiency in amplification of multilevel constellations without penalties on system performance when compared with common schemes using only beamforming.