By developing new mathematical descriptions of 4q (integer q 2) quadrature amplitude modulation (QAM) constellation, a novel construction producing 4q-QAM complementary sequences (CSs) of length 2m (integer m 2) is presented. The proposed sequences include the known 4q-QAM CSs constructed from Cases Ito III constructions, proposed by Li, as special cases. For 16-QAM CSs, the number of the resultant sequences is determined precisely. New sequences have a larger family size so as to increase the code rates. When used in orthogonal frequency-division multiplexing (OFDM) systems, new sequences possess the same peak envelope power (PEP) upper bounds as those of the known sequences referred to above.
