Compared with the quadrature amplitude modulation (QAM), the differential amplitude and phase-shift keying (DAPSK) modulation is simpler, especially in demodulation. Therefore, the DAPSK method has recently found many applications in orthogonal frequency division multiplexing (OFDM) systems. This paper evaluates the theoretical performance of the 16-, 32- and 64-level multilevel differential amplitude and phase-shift keying (MDAPSK) methods in OFDM systems in terms of the bit-error-rate (BER). This paper p...