关键词: 正交频分复用, 双选择衰落信道, 信道估计, 基扩展模型, 频谱泄露

Abstract: In terms of the deficiencies of channel estimation algorithm based on the Complex Exponential Basis Expansion Model（CE-BEM） in Orthogonal Frequency Division Multiplexing（OFDM） systems under doubly-selective fading channels, this paper proposes a new channel estimation algorithm based on windowed basis expansion model. The algorithm can be applied to reduce spectrum leakage which exists in CE-BEM through the time domain windowing and de-windowing processing, and suppress the influence of doppler shift to estimation performance. The mathematical model is simplified by using the designed pilot scheme；and then the estimated coefficients of CE-BEM are converted by orthogonal projection, and further improve the channel estimation accuracy. Besides, the Normalized Mean Square Error（NMSE） and Bit Error Rate（BER） are used to measure the channel estimation performance. Experimental simulation results demonstrate that the proposed algorithm can effectively improve the channel estimation performance in mobile environment with high speed.

Key words: Orthogonal Frequency Division Multiplexing（OFDM）, Doubly -Selective Fading Channels, channel estimation, Basis Expansion Model（BEM）, spectrum leakage