tailieunhanh - Báo cáo hóa học: " Research Article Channel Impulse Response Length and Noise Variance Estimation for OFDM Systems with Adaptive Guard Interval"

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 Channel Impulse Response Length and Noise Variance Estimation for OFDM Systems with Adaptive Guard Interval | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2007 Article ID 24342 13 pages doi 2007 24342 Research Article Channel Impulse Response Length and Noise Variance Estimation for OFDM Systems with Adaptive Guard Interval Van Duc Nguyen 1 Hans-Peter Kuchenbecker 2 Harald Haas 3 Kyandoghere Kyamakya 4 and Guillaume Gelle5 1 Department of Communication Engineering Faculty of Electronics and Telecommunications Hanoi University of Technology 1 Dai Co Viet Street Hanoi Vietnam 2 Institutfur Allgemeine Nachrichtentechnik Universitat Hannover Appelstrasse 9A 30167 Hannover Germany 3 School of Engineering and Science International University Bremen Campus Ring 12 28759 Bremen Germany 4 Department of Informatics-Systems Alpen Adria University Klagenfurt Universitătsstrasse 65-67 9020 Klagenfurt Austria 5 CReSTIC-DeCom University of Reims Champagne-Ardenne Moulin de la Housse BP 1039 51687 Reims Cedex 2 France Received 5 October 2005 Revised 16 August 2006 Accepted 14 November 2006 Recommended by Thushara Abhayapala A new algorithm estimating channel impulse response CIR length and noise variance for orthogonal frequency-division multiplexing OFDM systems with adaptive guard interval GI length is proposed. To estimate the CIR length and the noise variance the different statistical characteristics of the additive noise and the mobile radio channels are exploited. This difference is due to the fact that the variance of the channel coefficients depends on the position within the CIR whereas the noise variance of each estimated channel tap is equal. Moreover the channel can vary rapidly but its length changes more slowly than its coefficients. An auxiliary function is established to distinguish these characteristics. The CIR length and the noise variance are estimated by varying the parameters of this function. The proposed method provides reliable information of the estimated CIR length and the noise variance even at .