Constructions Of QAM Near Complementary Sequences

Orthogonal frequency division multiplexing (OFDM) technology has been widely applied to broadcast of audio, video and civil communication system, including radar, sonar, non-symmetrical digital subscriber loop (ADSL), wireless local area network, and the few standard of wireless communication system. Their popularity is mainly due to high spectral efficiency utilization and the robustness against anti multipath fading channels. In the OFDM signals, the pseudo random sequences determines the peak-to-mean envelope power ratio (PMEPR) of signals in the transmission process, and affecting the performance of the whole system. Therefore, the design for sequences of OFDM signals with low PMEPR has important significance.At present, the construction of codes with the feature of Golay complementary sequences from the traditional Reed-Muller codes, is an ideal method to reduce the PMEPR. This method is used for phase shift keying (PSK) modulation. As anoth-er method of reducing PMEPR, the pseudo-random sequences of orthogonal ampli-tude modulation (QAM) are composed of several groups of Golay complementary se-quences. This paper mainly constructs aperiodic QAM near complementary sequences. Based on two near complementary pairs from Stinchcombe and the theory of 16-QAM near complementary sequences with length 2m proposed by Lee and Golomb, we ob-tain some kinds of new 16,64-QAM near complementary sequences. The upper bound of peak envelope power ratio of new sequences and the proof of our theory was given as follows. These sequences, not only can provide new sequences with low PMEPR, but also generalize some known sequences.