Publish Date : 2/6/2011   Journal Name :   Pages : 4
A New Constellation in DMT for ADSL System


In this paper, three new constellations (NQAM, CIRC1
and CIRC2) are introduced instead of the most popular
quadrature amplitude modulation (QAM) in the discrete multitone
(DMT) system. For the comparison purpose, they have been
chosen so that they have the same average power. Also 8
standard channels (CSA#1 through CSA#8) with the AWGN
noise have been employed. Based on the simulation results, the
NQAM constellation has a better performance, in terms of the
BER, with respect to popular QAM constellation without any
increment in its complexity. The other two new constellations also
have better performances with respect to the QAM in
somewhere. Finally, for wirelined systems like the ADSL, the
proposed NQAM is a good choice instead of the QAM.

Authors : Saeed Ghazi-Maghrebi, Mojtaba Lotfizad, Mohammad Ghanbari