Compressed channel estimation with joint pilot symbol and placement design for high mobility OFDM systems

High mobility introduces significant Doppler frequency spread and hence imposes great challenge to channel estimation in orthogonal frequency division multiplexing (OFDM) systems. In this paper, we propose a new low coherence compressed channel estimation method for OFDM systems in the high mobility environment. Based on the compressed sensing (CS) coherence minimization criterion, we propose a new pilot design algorithm using the discrete stochastic optimization method to improve the estimation performance. The pilot symbol and pilot placement are jointly designed to obtain the optimal pilot. Numerical results demonstrate that the proposed method has a fast convergency property and achieves better MSE performance than existing channel estimation methods over high mobility channels.