In this article, main of the presented results are obtained by taking into account most as possible realistic working condition by the use of a global system evaluation scheme based on Agilent Technologies equipments. As presented in previous works, realistic consideration of the characteristics of transmission channel, the antenna coupling and also the channel correlation would indeed allow a fast and effective design of multiantenna wireless systems in order to obtain an important design cycle reducing. The first part presents the used global system level approach and the associated tools with some theoretical, simulated and measured results in order to validate the developed testbed radio plateform. In the second part, the three presented RF impairments are considered one by one in a Zero-IF down conversion structure and their effect on OFDM transmission performances are detailed. In the last part, after a short description of the SIMO processing that is used, the natural compensation of each RF impairment it is possible to obtained taking advantage of space diversity is presented. Results given in this part are obtained by taking into account different measured propagation channels (AWGN or fading channels) and a complete 802.11g structure.