tailieunhanh - Báo cáo hóa học: " Doubly Selective Channel Estimation Using Superimposed Training and Exponential Bases Models"

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: Doubly Selective Channel Estimation Using Superimposed Training and Exponential Bases Models | Hindawi Publishing Corporation EURASIP Journal on Applied Signal Processing Volume 2006 Article ID 85303 Pages 1-11 DOI ASP 2006 85303 Doubly Selective Channel Estimation Using Superimposed Training and Exponential Bases Models Jitendra K. Tugnait 1 Xiaohong Meng 1 2 and Shuangchi He1 1 Department of Electrical and Computer Engineering Auburn University Auburn AL 36849 USA 2 Department of Design Verification MIPS Technologies Inc. Mountain View CA 94043 USA Received 1 June 2005 Revised 2 June 2006 Accepted 4 June 2006 Channel estimation for single-input multiple-output SIMO frequency-selective time-varying channels is considered using superimposed training. The time-varying channel is assumed to be described by a complex exponential basis expansion model CE-BEM . A periodic nonrandom training sequence is arithmetically added superimposed at a low power to the information sequence at the transmitter before modulation and transmission. A two-step approach is adopted where in the first step we estimate the channel using CE-BEM and only the first-order statistics of the data. Using the estimated channel from the first step a Viterbi detector is used to estimate the information sequence. In the second step a deterministic maximum-likelihood DML approach is used to iteratively estimate the SIMO channel and the information sequences sequentially based on CE-BEM. Three illustrative computer simulation examples are presented including two where a frequency-selective channel is randomly generated with different Doppler spreads via Jakes model. Copyright 2006 Hindawi Publishing Corporation. All rights reserved. 1. INTRODUCTION Consider a time-varying SIMO single-input multiple-output FIR finite impulse response linear channel with N outputs. Let s n denote a scalar sequence which is input to the SIMO time-varying channel with discrete-time impulse response h n 1 N-vector channel response at time n to a unit input at time n-1 . The vector channel may be the result of .