Channel Estimators for LTE-A Downlink Fast Fading Channels

In this paper, we present channel estimators for Long Term Evolution Advanced (LTE-A) fast fading channels. We show that the LTE-A Reference Signals (RS) structure - despite being designed for rather static scenarios - allows for accurate estimation performance even for higher speeds. We derive a Linear Minimum Mean Square Error (LMMSE) estimator and outline the restrictions that the LTE-A standard places on this estimator. Moreover, we present a novel Least Squares (LS) estimator based on a smoothness constraint, attempting to approach the performance of the LMMSE estimator, as our simulations reveal the rather limited capabilities of conventional interpolation techniques.