Novel Adaptive Modulation Scheme to Reduce both PAR and ICI of an OFDM Signal

Orthogonal Frequency Division Multiplexing (OFDM), a promising technique to support high-bit-rate wireless systems, is limited by potentially large Peak-to-Average Power ratio (PAR) and Intercarrier Interference (ICI) due to frequency offset errors. Several techniques proposed in the literature treat these limitations as two separate problems. This paper shows that a simple adaptive modulation scheme is effective in reducing the both PAR and ICI simultaneously. We propose the use of M-point Zero-padded Phase Shift Keying (M-ZPSK), which includes a signal point of zero amplitude, as a modulation scheme. We evaluate the performance of the proposed scheme analytically and by simulation. Keywords— Orthogonal Frequency Division Multiplexing, Peak-toAverage Power ratio (PAR), Carrier Frequency Offset (CFO), Intercarrier Interference (ICI)