Comparison of Derivative Based and Derivative Free Kalman Filters for Multipath Channel Estimation in CDMA Networks

The paper compares time delay and channel gain estimation for multipath fading code division multiple access (CDMA) signals using the derivative based and derivative free Kalman filters. We will be investigating the performance of the derivative based Kalman filter namely extended Kalman Filter (EKF) with the derivative free sigma point kalman filters (SPKF), namely the unscented Kalman Filter (UKF) and the 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 achieves 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 simulation results also demonstrates that the proposed SPKF algorithms are simpler to implement, and more resilient to near-far interference in CDMA networks.