Model based approach for time-varying channel estimation in DS-CDMA systems using non-isotropic scattering environment

This paper deals with the estimation of rapidly time varying non isotropic Rayleigh fading channels in synchronous direct sequence spread spectrum (DS-CDMA) systems. The effects of non isotropic scattering can be captured by using Von Mises distribution for the angle of arrival (AOA) of the scattered waves at the receiver. Kalman Filter based on higher order autoregressive (AR) model is used for tracking and estimation of the non isotropic Rayleigh channel. The proposed algorithm works much better than AR(1) based algorithms in tracking time varying channel especially on high Doppler spreads in directional scenarios. However, it is observed, the computational cost of the proposed algorithm increases when the AR model order increases.