  To obtain channel information for further data transmission, the blind
channel estimation needs no pilot signal in advance is a considerable
algorithm. To improve performance of the blind channel estimation schemes, we
have employed the channel estimation with pilot signals by adjacent users; the
acquired estimation channel information of the adjacent channel is applied as
an initial state to the blind channel estimation of the target user. We have
considered the subspace blind channel estimation scheme in this study. The
estimated adjacent channel information is supported as an initial state of the
auto-correlation matrix in the subspace estimation method, thereby providing
information to reduce the channel estimation error. From our simulation study,
we have found that, when the correlation between two nearby channels is high,
the forgetting factor in the subspace estimation method can be increased, so
that the weight of the initial state of the matrix is increased, and a more
accurate channel state is estimated. If the correlation coefficient is lowered
in two adjacent channels, the forgetting factor can be appropriately adjusted
to rise the weight of the direct received signal from the objective channel to
avoid errors increased.
