For the technical challenges brought by time/frequency-domain selective fading (double-selective fading) and non-stationary characteristics in channel estimation for orthogonal frequency division multiplexing (OFDM) system

an iterative extend-Kalman filter (iEKF) channel estimation method based on basis expansion model (BEM) with the frame structure of superimposed pilot is proposed.Based on the BEM and the EKF channel estimation method

the channel impulse response (CIR) and the time-varying time-domain autocorrelation coefficient can be jointly estimated to effectively eliminate inter carrier interference (ICI).At the same time

it's need to eliminate the interference of data symbols at the superimposed position.So for the superimposed position

the channel estimation is proposed in which decoupling data and pilot firstly

reconstructing subsequently

and performing the iEKF algorithm finally.The simulation analysis shows that compared with the traditional superimposed pilot channel estimation method and the pilot symbol assisted modulation (PSAM) estimation method

the proposed channel estimation method has higher estimation accuracy

stronger robustness and greaterer throughput in high-speed railway scenario especially under low signal-to-noise ratio (SNR) conditions.