Abstract: A new blind multiuser detection algorithm was proposed on the basis of complex FastICA in MIMOOFDM system. With the proposed algorithm， the separation of multiuser could be speeded up by fast convergence characteristics of complex FastICA algorithm firstly， and the indeterminacy of amplitude and indeterminacy of phase by CFastICA algorithm were revised by using correlation function. At last， comparing the improved algorithm with the complex natural gradient learning algorithm(CNGLA)， it was proved that CFastICA algorithm has not only faster convergent speed but also smaller bit error rate. It also indicated that using more numbers of receiving antennas would get better signal separation.

Key words: MIMOOFDM system, complex FastICA algorithm, blind multiuser detection, indeterminacy of amplitude, indeterminacy of phase