Reducing Intercarrier Interference in OFDM Systems by Partial Transmit Sequence and Selected Mapping

Orthogonal Frequency Division Multiplexing (OFDM) is sensitive to the carrier frequency offset (CFO). We introduce the Peak Interference-to-Carrier Ratio (PICR) to measure the resulting intercarrier interference (ICI). This paper shows that PICR can be reduced by Partial Transmit Sequence (PTS) and Selected Mapping (SLM) approaches. In PTS, each block of subcarriers is multiplied by a constant phase factor and these phase factors are optimized to minimize the PICR. In SLM, several independent OFDM symbols representing the same information are generated and the OFDM symbol with lowest PICR is selected for transmission. These schemes are analyzed theoretically and their performances are evaluated by simulation. Keywords— Orthogonal Frequency Division Multiplexing, Carrier Frequency Offset (CFO), Intercarrier Interference (ICI)