The goal of this project is to determine the effect of an imperfect channel estimation on the pre-processing schemes efficiency. Pre-processing is an unavoidable concern in MIMO transmission, especially on the pre-processing techniques investigated: Eigenmode-transmission, Water-filing, and Adaptive modulation and coding. The impact of noise and Doppler CSI imperfection on MIMO systems are investigated using mathematical models and computer simulations. The results are showing that the quality of the estimation channel is crucial for multi-antenna systems.