tailieunhanh - Báo cáo hóa học: " Research Article Simple Statistical Analysis of the Impact of Some Nonidealities in Downstream VDSL with Linear Precoding"

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 Simple Statistical Analysis of the Impact of Some Nonidealities in Downstream VDSL with Linear Precoding | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2010 Article ID 454871 14 pages doi 2010 454871 Research Article Simple Statistical Analysis of the Impact of Some Nonidealities in Downstream VDSL with Linear Precoding Marco Baldi 1 Franco Chiaraluce 1 Roberto Garello 2 Marco Polano 3 and Marcello Valentini3 1 Dipartimento di Ingegneria Biomedica Elettronica e Telecomunicazioni Universita Politecnica delle Marche 60131 Ancona Italy 2Dipartimento di Elettronica Politecnico di Torino 10129 Torino Italy 3 Telecom Italia Via Guglielmo Reiss Romoli 274 10148 Torino Italy Correspondence should be addressed to Franco Chiaraluce Received 1 June 2010 Revised 27 August 2010 Accepted 16 September 2010 Academic Editor George Tombras Copyright 2010 Marco Baldi 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. This paper considers a VDSL downstream system where crosstalk is compensated by linear precoding. Starting from a recently introduced mathematical model for FEXT channels simple analytical methods are derived for evaluating the average bit rates achievable taking into account three of the most important nonidealities. First absolute and relative estimation errors in the crosstalk coefficients are discussed and explicit formulas are obtained to express their impact. A simple approach is presented for computing the maximum line length where linear precoding overcomes the noncoordinate system. Then the effect of out-ofdomain crosstalk is analyzed. Finally quantization errors in precoding coefficients are considered. We show that by the assumption of a midtread quantization law with different thresholds a relatively small number of quantization bits is sufficient thus reducing the implementation complexity. The presented formulas allow to .