tailieunhanh - Báo cáo hóa học: " Performance Evaluation of Linear Turbo Receivers Using Analytical Extrinsic Information Transfer Functions"

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 Evaluation of Linear Turbo Receivers Using Analytical Extrinsic Information Transfer Functions | EURASIP Journal on Applied Signal Processing 2005 6 892-905 2005 Hindawi Publishing Corporation Performance Evaluation of Linear Turbo Receivers Using Analytical Extrinsic Information Transfer Functions Cesar Hermosilla Department of Electronic Engineering Technical University Federico Santa Maria Valparaiso 239-0123 Chile Em ail hermosil@ Leszek Szczecinski Institut National de la Recherche Scientifique-Energie Materiaux et Telecommunications Universite du Quebec Montreal Quebec Canada J3X1S2 Email leszek@ Received 13 October 2003 Revised 16 July 2004 Turbo receivers reduce the effect of the interference-limited propagation channels through the iterative exchange of information between the front-end receiver and the channel decoder. Such an iterative turbo process is difficult to describe in a closed form so the performance evaluation is often done by means of extensive numerical simulations. Analytical methods for performance evaluation have also been proposed in the literature based on Gaussian approximation of the output of the linear signal combiner. In this paper we propose to use mutual information to parameterize the logarithmic-likelihood ratios LLRs at the input output of the decoder casting our approach into the framework of extrinsic information transfer EXIT analysis. We find the EXIT functions of the front-end FE receiver analytically that is using solely the information about the channel state. This is done decomposing the FE receiver into elementary blocks described independently. Our method gives an insight into the principle of functioning of the linear turbo receivers allows for an accurate calculation of the expected bit error rate in each iteration and is more flexible than the one previously used in the literature allowing us to analyze the performance for various FE structures. We compare the proposed analytical method with the results of simulated data transmission in case of multiple antennas .