Adaptive channel estimation using frequency-response-shaped LMS algorithm in DS-CDMA systems

An adaptive least mean square (LMS) type channel estimation algorithm is proposed. The proposed algorithm employs the frequency-response-shaped least mean square (FRS-LMS) algorithm which outperforms the LMS and the modified leaky LMS algorithms in a fading channel with correlated Gaussian noise. The algorithm is based on shaping the frequency response of the transversal filter by inclusion of a leakage factor in matrix form. The FRS-LMS algorithm converges to a lower MSE compared with the modified leaky LMS in correlated Gaussian noise leading to a substantial decrease in bit error rate for direct sequence code division multiple access (DS-CDMA) systems. In a fading channel with AWGN, the proposed algorithm has a lower performance gain relative to the modified leaky LMS algorithm but provides a significant performance advantage over the standard LMS algorithm of the system.