AN ENHANCED LMMSE CHANNEL ESTIMATION METHOD FOR OFDM SYSTEMS WITH VIRTUAL SUBCARRIERS

Linear Minimum Mean Square Error (LMMSE) channel estimator has excellent Mean Square Error (MSE) performance in Orthogonal Frequency Division Multiplexing (OFDM) systems. However, two main reasons limit the usefulness of theoretical LMMSE method in practical systems. First, the channel power delay profiles (PDP) are unknown in practical system, and due to the existence of virtual subcarriers, the difficulty in estimating PDP increases. Second, the computation complexity is high. In this case, an enhaneed LMMSE channel estimation method for OFDM systems with virtual subcarriers is proposed to approach the performance of theoretical LMMSE method with low computation complexity and no requirement on the detailed channel information. The simulation results indicate that the pro posed method outperforms conventional channel estimation methods and achieves approximate performance of theoretical LMMSE method in terms of MSE and Bit Error Rate (BER).