Abstract: 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 interms of the bit-error-rate (BER). This paper presents detailed analysis ofthe BERs for the MDAPSK-OFDM signals in an additive white Gauss noise (AWGN) channel and obtains closed-form BER expressions. The theoretical results are verified by computer simulations. The computer simulation results reveal the advantages of using the 16DAPSK or 64DAPSK method in experimental OFDM systems.

Key words: multilevel differential amplitude and phase-shift keying, orthogonal frequency division multiplexing, bit-error-rate