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: PSD-Constrained PAR Reduction for DMT/OFDM | EURASIP Journal on Applied Signal Processing 2004 10 1498-1507 2004 Hindawi Publishing Corporation PSD-Constrained PAR Reduction for DMT OFDM Niklas Andgart Signal Processing Group Department of Information Technology Lund University . Box 118 221 00 Lund Sweden Email Brian S. Krongold Australian Research Council ARC Special Research Centre for Ultra-Broadband Information Networks University of Melbourne Victoria 3010 Australia Email bsk@ Per idling Signal Processing Group Department of Information Technology Lund University . Box 118 221 00 Lund Sweden Email Albin Johansson Ericsson AB 12625 Stockholm Sweden Email Per Ola Borjesson Signal Processing Group Department of Information Technology Lund University . Box 118 221 00 Lund Sweden Email per. Received 28 February 2003 Revised 30 January 2004 Common to all DMT OFDM systems is a large peak-to-average ratio PAR which can lead to low power efficiency and nonlinear distortion. Tone reservation uses unused or reserved tones to design a peak-canceling signal to lower the PAR of a transmit block. In DMT ADSL systems the power allocated to these tones may be limited due to crosstalk issues with many users in one twisted pair bundle. This PSD limitation not only limits PAR reduction ability but also makes the optimization problem more challenging to solve. Extending the recently proposed active set tone reservation method we develop an efficient algorithm with performance close to the optimal solution. Keywords and phrases peak-to-average ratio tone reservation OFDM DMT. 1. INTRODUCTION Communication systems using multicarrier modulation have recently become widely used both in wireless DVB-T DAB IEEE and wireline ADSL VDSL environments 1 2 3 . Multicarrier systems have distinct advantages over single-carrier systems but suffer from a serious drawback the approximately Gaussian-distributed .
