Common and Dedicated Pilot-Based Channel Estimates Combining and Kalman Filtering for WCDMA Terminals

Abstract

We consider a family of user dedicated downlink channel estimation methods in WCDMA receivers which are particularly suited for the presence of dedicated channel transmit beamforming and which assume no a priori knowledge of the path delays and the beamforming parameters. They exploit all the transmitted pilot sequences as well as the structured dynamics of the channel. First we build slot-wise least squares (LS) estimates of the channels associated with dedicated and common pilots. Then we optimally improve the dedicated channel estimate quality by jointly Kalman filtering the two LS estimates or alternatively (suboptimally) Kalman filtering them separately and combining via weighted LS. In the suboptimal case, the order of Kalman filtering and weighted LS combining results in differing performance and complexity in different conditions