tailieunhanh - Báo cáo hóa học: " Performance Analysis of Multiple-Symbol Differential Detection for OFDM over Both Time- and Frequency-Selective Rayleigh Fading Channels"

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: Performance Analysis of Multiple-Symbol Differential Detection for OFDM over Both Time- and Frequency-Selective Rayleigh Fading Channels | EURASIP Journal on Applied Signal Processing 2004 10 1536-1545 2004 Hindawi Publishing Corporation Performance Analysis of Multiple-Symbol Differential Detection for OFDM over Both Time- and Frequency-Selective Rayleigh Fading Channels Akira Ishii Department of Communications and Systems University of Electro-Communications 1-5-1 Chofugaoka Chofu-shi Tokyo 182-8585 Japan Email Hideki Ochiai Division of Physics Electrical and Computer Engineering Yokohama National University 79-1 Tokiwadai Hodogaya-ku Yokohama 240-8501 Japan Email hideki@ Tadashi Fujino Department of Communications and Systems University of Electro-Communications 1-5-1 Chofugaoka Chofu-shi Tokyo 182-8585 Japan Email fujino@ Received 28 February 2003 Revised 8 October 2003 The performance of orthogonal frequency-division multiplexing OFDM system with multiple-symbol differential detection MSDD is analyzed over both time- and frequency-selective Rayleigh fading channels. The optimal decision metrics of timedomain MSDD TD-MSDD and frequency-domain MSDD FD-MSDD are derived by calculating the exact covariance matrix under the assumption that the guard time is longer than the delay spread thus causing no effective intersymbol interference ISI . Since the complexity of calculating the exact covariance matrix turns out to be substantial for FD-MSDD we also develop a sub-optimal metric based on the simplified covariance matrix. The comparative analysis between TD-MSDD and FD-MSDD suggests that the most significant improvement is achieved by the FD-MSDD with the optimal metric and a large symbol observation interval since the time selectiveness of the channel has a dominant effect on the bit error rate of the OFDM system. Keywords and phrases orthogonal frequency-division multiplexing multiple-symbol differential detection time- and frequency-selective channels Rayleigh fading. 1. INTRODUCTION In mobile communications systems there has been a growing demand for high data