Channel Estimation with Lowpass Filter for UTRA FDD Downlink

This paper introduces a new Channel Estimation (CE) filter called Polyphase Lowpass-Interpolation (PLI)-filter for downlink coherent Rake-combining in a DSCDMA mobile environment. In this case some UTRA FDD scenarios are taken for showing the feasibility of this approach. It uses known periodically time-multiplexed pilot symbols for interpolating the channel coefficients in between. The idea of this approach is to find a compromise between noise reduction and adaptation to the time variant channel coefficients using a Remez lowpass design. This is paid by the use of at least six pilot sequences resulting in a three slot delay. Some simulation results of this PLI-filter compared with other well known CE-filters are presented.