IMM Based Kalman Filter for Channel Estimation in UWB OFDM Systems

Ultra-wide band (UWB) communication is one of the most promising technologies for high data rate wireless networks for short range applications. This paper proposes a blind channel estimation method namely IMM (interactive multiple model) based Kalman algorithm for UWB OFDM systems. IMM based Kalman filter is proposed to estimate frequency selective time varying channel. In the proposed method, two Kalman filters are concurrently estimating channel parameters. The first Kalman filter, namely the static model filter (SMF) gives an accurate result when the user is static while the second Kalman filter namely the dynamic model filter (DMF) gives an accurate result when the receiver is in moving state. The static transition matrix in SMF is assumed as an identity matrix where as in DMF, it is computed using Yule-Walker equations. The resultant filter estimate is computed as a weighted sum of individual filter estimates. The proposed method is compared with other existing channel estimation methods