Efficient Channel Estimation for OFDM Systems with Reduced Pilot Overhead

Channel estimation for orthogonal frequency division multiplexing (OFDM) systems stands for an important issue in mobile broadband communications, where a class of methods based on training symbols, also known as pilots, have been widely studied. Aiming at improving the spectrum efficiency and reducing the transmission latency, we tend to approach the minimal pilot overhead for OFDM systems by proposing a two-stage channel estimation method. Specifically, in the first stage, the initial value of the channel frequency response is obtained by the discrete Fourier transform (DFT)-based estimator. Then, in the second stage, soft-decision is performed to select the components with high confidence, and thus the complete channel estimation value is reconstructed by employing the compressed sensing technology. Simulations show that the proposed scheme yields considerable improvements in both bit error rate (BER) performance and data transmission efficiency.