An improved method for reconstruction of channel taps in OFDM systems

In this paper, an improved method for reconstruction of doubly selective wireless channels in piloted-aided OFDM systems based an existing estimation method is proposed. In this re-expansion channel estimation process, the first few Fourier coefficients of each channel tap are estimated from the pilot information and the received signal firstly. Then the channel taps are estimated in the framework of Basis Expansion Model (BEM) from their respective Fourier coefficients. In the process of recovering BEM coefficients, instead of using the inverse method which is a Least Square (LS) problem, this paper proposes an improved method of recovering BEM coefficients from the estimated Fourier coefficients based on the Minimum Mean Square Error (MMSE) criterion. The proposed method is validated by simulating a system conforming to the IEEE 802.16e standard. Numerical results illustrate the performance gains achieved by the improved method.