Low complexity channel estimation for 3GPP LTE downlink MIMO OFDM systems

Multiple Input Multiple Output - Orthogonal Frequency Division Multiplexing (MIMO-OFDM) is a promising technique for reaching high data rates targeted in the 3rd Generation Partnership Project - Long Term Evolution (3GPP-LTE). MIMO-OFDM channel estimation schemes play a very important role on achieving this aim. However, the complexity of the estimators increases exponentially due to the structure of the MIMO systems. This causes an increase in the computational burden of the transceivers. As a result, the complexity of the channel estimators is becoming an important issue in real world MIMO-OFDM applications. In this paper, the performance of the low complexity Minimum Mean Square Error (MMSE) channel estimator scheme based on Karhunen-Loéve (KL) series expansion coefficients for the 3GPP-LTE Downlink MIMO-OFDM systems is examined. System level simulations are accomplished to compare the performances of the estimators under the spatially correlated channel coefficient variations.