Sigma Point Kalman Filters for multipath channel estimation in CDMA networks

The paper investigates time delay and channel gain estimation for multipath fading Code Division Multiple Access (CDMA) signals using the Sigma Point Kalman Filters (SPKF), namely Unscented Kalman Filter (UKF) and second order Divided Difference Filter (DDF). Given the nonlinear dependency of the channel parameters on the received signals in multiuser/multipath scenarios, we show that the SPKF achieve better performance than its linear counterparts. This derivative-free Kalman filtering approach, avoids the errors associated with linearization in the conventional Extended Kalman Filter (EKF). The numerical results also show that the proposed SPKF algorithms are simpler to implement, and more resilient to near-far interference in CDMA networks.