Abstract: In this paper, the impact of Gaussian estimation error on the performance of vertical bell labslayered space-time (V-BLAST) architecture is investigated by using maximum likelihood (ML) receiver inindependently and identically distributed (i.i.d.) Rayleigh fading channel. Based on the statistical property ofsquared Euclidean distance, the pairwise error probability (PEP) for V-BLAST system over i.i.d. Rayleigh fadingchannel with channel estimate error is derived. The approximate expression of the PEP for high signal-to-noiseration (SNR) region is used to analyze the loss of diversity order and penalty of SNR. It shows that the diversityorder achieved by ML receiver is not affected by channel estimation error and the loss of SNR due to imperfectchannel estimation is 3 dB. Simulation results are given to corroborate the theoretical analysis.