This paper provides concept of data transmission protocol for millimeter wave (mmWave) wireless systems operating in Non-Line-of-Sight environment. This concept is designed to provide an effective and practical functioning of Multiple-Input Multiple-Output (MIMO) transmission mode that exploits combination of Singular Value Decomposition (SVD) of channel matrix and non-adaptive beamforming. The proposed protocol reduces complexity of implementation of the beamformed MIMO system with SVD by transmitting the special signals, called by MIMO postambles. Using these MIMO postambles allows stations to obtain the channel state information and operate in SVD mode without any feedback and simplifies MIMO system architecture significantly.