Construction of non-square M-QAM sequences with low PMEPR for OFDM systems

The author considers the use of coding to reduce the peak-to-mean envelope power ratio (PMEPR) for orthogonal frequency division multiplexing (OFDM) systems. Most of the existing schemes that use coding for PMEPR reduction assume a PSK constellation. The author presents the construction of non-square M-QAM symbols from a combination of QPSK and BPSK signals when M=2ⁿ and n is an odd number. By using QPSK and BPSK Golay (or Golay-like) sequences, M-QAM sequences with low PMEPR are generated. An upper bound for the instantaneous envelope power of Golay-like M-QAM sequences was derived. After the mean envelope power for these sequences was computed, the general upper bound for one PMEPR of M-QAM sequences with non-square constellations was derived.