研究了天線分集OFDM系統的高速無線數據傳輸特點，通過計算信道沖擊響應與參考信號的相關函數，提出了一種增強型的信道估計方法。理論分析與計算機仿真表明，該方法能夠有效地降低加性噪聲對信道估計的影響，提高信道估計精度。在采用QPSK調制的一發四收的接收分集OFDM系統中，該增強型的信道估計方法的性能明顯好于最小二乘信道估計和基于DFT的信道估計。
關 鍵 詞 OFDM系統; 信道估計; 接收分集; 多徑衰落信道

Research on Channel Estimation for OFDM Systems with
Receiver Diversity
Han Bing Gao Xiqi You Xiaohu
(National Communication Research Lab, Southeast University Nanjing 210096)
Abstract Receiver diversity for Orthogonal Frequency Division Multiplexing system in high-speed wireless data transmission is investigated. An improved channel estimate method that calculates the correlation of the channel impulse response and a reference signal to extract the channel information from its noisy version is proposed. It is demonstrated by theoretical analysis and computer simulation that for QPSK modulated OFDM systems with one transmitter antenna and four receiver antennas, the performance of the improved channel estimator outperforms Least Square and Discrete Fourier Transform-based channel estimator greatly.
Key words OFDM system; channel estimation; receiver diversity; multipath fading channel