Robust minimum mean square error channel estimation for LTE downlink OFDM system

Abstract

This paper deals with the robust minimum mean square error (MMSE) channel estimation for LTE (Long Term Evolution) downlink OFDM (Orthogonal Frequency Division Multiplexing) system over time varying mobile environments. Recently robust estimators are proposed for OFDM systems with block type pilot structure. These estimators do not require channel correlation functions for estimation and give robust performance independent of actual power delay profile (PDP). However, LTE pilot structure is a combination of both block type and comb type pilot structure. Hence, there is a need to develop a channel estimator giving robust performance for LTE system. This allows the system to be deployed in rural areas having complex mobile environment such as more mud houses and dense trees. The mean square error (MSE) performance of the proposed estimator is analyzed with various power delay profiles applicable to LTE systems. Analytical expressions are derived for MSE and it is verified that both analytical and simulation results are exactly matching.