Position-Based Compressed Channel Estimation and Pilot Design for High-Mobility OFDM Systems

Due to the development of High-Speed Trains (HSTs) in many countries, providing broadband wireless services in HSTs is crucial. Orthogonal Frequency-Division Multiplexing (OFDM) has been widely adopted for broadband wireless communications due to its high spectral efficiency. However, OFDM is sensitive to the time selectiv ity caused by high -mobility channels, which costs much spectrum or time resources to obtain the accurate Channel State Information (CSI). Here, a new position -based highmobility channel model is proposed, in which the HST’s position information and Doppler shift are utilized to determine the positions of the dominant channel coefficients. Then, a joint pilot placement and pilot symbol design algorithm for compressed channel estimation is proposed. Simulation results demonstrate that the proposed method performs better than existing channel estimation methods over high-mobility channels.