LMMSE-Based Channel Estimation for LTE-Advanced MIMO Downlink Employing UE-Specific Reference Signals

The LTE-Advanced wireless communication standard specifies UE-specific reference signals (short-named DM-RS) to facilitate multi-input multi-output (MIMO) downlink channel estimation. This paper presents a linear minimum mean-square error (LMMSE)-based channel estimation technique in this context. Key to LMMSE channel estimation is the acquisition of some second-order channel statistics, for which the present work adopts a previously proposed approach that employs a parametric model for the channel autocorrelation function and estimates the model parameters from the received DM-RS. While such MIMO transmission is usually considered applicable to slow motion, our results show that the channel estimation technique itself can accommodate much faster motion.