Selected Mapping in Correlatively Coded OFDM

The peak-to-average raito (PAPR) in correlatively coded orthogonal frequency-division multiplexing (OFDM) system is studied. Correlative codes are proposed by large numbers of papers to significantly improve the spectral performance of OFDM with rectangular pulse. The large PAPR makes amplifier distort the signal before transmission and thus becomes one of the most serious drawbacks of OFDM. However, simulations illustrate that correlatively coded OFDM has much larger PAPR than uncoded OFDM. This makes its implementation very difficult. Selected mapping (SLM) is a promising PAPR reduction technique, which is distortionless and has good PAPR reducing performance. We use SLM to reduce the PAPR of correlatively coded OFDM, and prove that the very high spectral efficiency is not affected by the PAPR reduction. Simulations show that SLM can lower the PAPR of correlatively code OFDM efficiently without any loss of the spectral performance.