Space-time codes exploit the presence of multiple transmit and receive antennas to improve communication performance on multipath radio channels.Increasing the number of antennas increases the required training interval for channel estimation and reduces the available time in which data may be transmitted.In this paper

by combining the subspace method with the special structure of space-time block code

we propose a blind channel estimation algorithm

which does not require any training symbol.With the special structure of space-time block code

in the received signal

the vectors of channel fading matrix have some relation with each other.Combining this relation with subspace method

we can accomplish the blind channel estimation.Monte Carlo simulations show that when the SNR is low

the loss in decoding performance incurred by the error of channel estimate is relatively small.