BEM-based Channel Estimation and Interpolation Methods for Doubly-selective OFDM Channel

In high-speed environments, the time and frequency selective (doubly-selective) channel which introduces the inter-carrier interference (ICI) into OFDM system is a big challenge for receiver design. The cost of computation complexity for eliminating ICI is very high with traditional channel estimation methods. For decreasing the complexity of doubly-selective channel estimation, the base expansion model (BEM) which could eliminate ICI is adopted in this paper to reduce space complexity. At the same time, some classical interpolation algorithms based on BEM are presented, including spline interpolation, Sinc interpolation, cubic B-spline interpolation and Lagrange interpolation In order to further improve the accuracy of channel interpolation, a modified Lagrange interpolation method is also proposed in this paper which could segment the interpolation interval and find the mean value of the interpolation. Finally, the complexity and the performance in all aspects including estimation accuracy, bit error rate (BER) and robustness of above interpolation methods are compared and analyzed by simulation with MATLAB.