A new constellation in DMT for ADSL systems

In this paper, three new constellations (NQAM, CIRC1 and CIRC2) are introduced instead of the most popular quadrature amplitude modulation (QAM) in the discrete multi-tone (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.