Time Reversal (TiR) technique is an effective and simple method for data transmission in extremely multipath indoor UWB channels that mitigates the complexity of receiver by its own time focusing feature. Although, TiR method has the suitable performance, but it is sensitive to the non-ideal channel estimation error. In this paper at first, the bit error probability of TiR-UWB communication systems with the simple matched filter receiver and in different conditions of the channel estimation error is calculated in closed-form.Then, for improvement of the performance of the TiR-UWB system in such conditions, a pre-filter in transmitter is proposed as two stage iteration-based improvement algorithm that approaches the channel estimation error to zero in 4 steps for the TiR-UWB system including the simple matched filter receiver by means of the calculated pre-filter in the TiR-UWB system consisting on the optimal MMSE estimator. Furthermore, it is indicated analytically that the designed pre-filter depends on the existent channel estimation error covariance. The obtained equations are compared with simulations and are shown to be in good agreement.