tailieunhanh - Báo cáo hóa học: "Research Article DFT-Based Channel Estimation with Symmetric Extension for OFDMA Systems"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article DFT-Based Channel Estimation with Symmetric Extension for OFDMA Systems | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2009 Article ID 647130 8 pages doi 2009 647130 Research Article DFT-Based Channel Estimation with Symmetric Extension for OFDMA Systems Yi Wang 1 2 Lihua Li 1 2 Ping Zhang 1 2 and Zemin Liu1 2 1Key Laboratory of Universal Wireless Communications Beijing University of Posts and Telecommunication Ministry of Education Beijing 100876 China 2Wireless Technology Innovation Institute Beijing University of Posts and Telecommunication Beijing 100876 China Correspondence should be addressed to Yi Wang wangyi81@ Received 31 July 2008 Revised 10 November 2008 Accepted 18 January 2009 Recommended by Yan Zhang A novel partial frequency response channel estimator is proposed for OFDMA systems. First the partial frequency response is obtained by least square LS method. The conventional discrete Fourier transform DFT method will eliminate the noise in time domain. However after inverse discrete Fourier transform IDFT of partial frequency response the channel impulse response will leak to all taps. As the leakage power and noise are mixed up the conventional method will not only eliminate the noise but also lose the useful leaked channel impulse response and result in mean square error MSE floor. In order to reduce MSE of the conventional DFT estimator we have proposed the novel symmetric extension method to reduce the leakage power. The estimates of partial frequency response are extended symmetrically. After IDFT of the symmetric extended signal the leakage power of channel impulse response is self-cancelled efficiently. Then the noise power can be eliminated with very small leakage power loss. The computational complexity is very small and the simulation results show that the accuracy of our estimator has increased significantly compared with the conventional DFT-based channel estimator. Copyright 2009 Yi Wang et al. This is an open access article distributed under .