Peak Power Reduction Method Based on Structure of Parity-Check Matrix for LDPC Coded OFDM Transmission

In this paper, we propose a peak power reduction method for LDPC coded OFDM system, where transmit data sequence is grouped into several clusters based on structure of a low density parity-check matrix and the phase or each cluster is adjusted so as to minimize PAPR of OFDM signal by multiplying weighting factors (WFs). At the receiver, WFs are estimated with sufficient accuracy by exploiting the decoding property of LDPC code. The proposed method can be applied to not only systematic coded signal but also non-systematic one. Computer simulation results show that, when LDPC code with code-rate of R ap 1/2 is used, PAPR of OFDM signal can be reduced by about 2.4 dB without significant degradation in BLER performance as compared to perfect WF estimation in attenuated 12-path Rayleigh fading condition.