Iterative EKF Channel Estimation Method Based on Superimposed Pilot in High Mobility Scenarios
LIAO Yong1, ZHANG Nan1, YAO Hai-mei1, HUA Yuan-xiao1, ZHAO Yan2
1. Center of Communication and TT&C, Chongqing University, Chongqing 400044, China;
2. . 61212 Unit of the People's Liberation Army, Beijing 100043, China
Abstract: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.
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