tailieunhanh - Báo cáo hóa học: " Research Article Blind Estimation of the Phase and Carrier Frequency Offsets for LDPC-Coded 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 Blind Estimation of the Phase and Carrier Frequency Offsets for LDPC-Coded Systems | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2010 Article ID 293572 13 pages doi 2010 293572 Research Article Blind Estimation of the Phase and Carrier Frequency Offsets for LDPC-Coded Systems Rodrigue Imad 1 Sebastien Houcke 2 and Mounir Ghogho EURASIP Member 3 4 1 Alcatel-Lucent Bell Labs INRIA 91620 Nozay France 2Institut Telecom Telecom Bretagne Universite Europeenne de Bretagne UMR CNRS 3192 Lab-STICC Technopôle Brest-Iroise CS 83818 29238 Brest Cedex 3 France 3 School of Electronic and Electrical Engineering University of Leeds Leeds LS2 9JT UK 4 International University of Rabat Rabat Morocco Correspondence should be addressed to Rodrigue Imad rodrigueimad@ Received 2 September 2010 Accepted 24 November 2010 Academic Editor Magnus Jansson Copyright 2010 Rodrigue Imad et al. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. We consider in this paper the problem of phase offset and Carrier Frequency Offset CFO estimation for Low-Density ParityCheck LDPC coded systems. We propose new blind estimation techniques based on the calculation and minimization of functions of the Log-Likelihood Ratios LLR of the syndrome elements obtained according to the parity check matrix of the error-correcting code. In the first part of this paper we consider phase offset estimation for a Binary Phase Shift Keying BPSK modulation and propose a novel estimation technique. Simulation results show that the proposed method is very effective and outperforms many existing algorithms. Then we modify the estimation criterion so that it can work for higher-order modulations. One interesting feature of the proposed algorithm when applied to high-order modulations is that the phase offset of the channel can be blindly estimated without any ambiguity. In the second part of the