Power Techniques for Blind Adaptive Channel Estimation in CDMA Systems

The problem of blind adaptive channel estimation, in code-division multiple-access (CDMA) systems, is considered. Using only the spreading code of the user of interest and the received data, adaptive techniques are proposed that blindly identify the impulse response of the multipath channel. In particular, we develop RLS and LMS implementations that exhibit rapid convergence combined with low computational complexity. Both versions were inspired by the iterative power method used in numerical analysis to compute the singular vector corresponding to the largest singular value of a matrix. This is the reason why our schemes exhibit performance comparable to SVD off-line techniques while outperforming, significantly, existing adaptive methods proposed in the literature.