A New Method to Reduce the PAPR in the IRA-OFDM System

First, an irregular repeat accumulate (IRA) coded orthogonal frequency division multiplexing (OFDM) system is introduced in this paper. To reduce the peak-to-average power ratio (PAPR) of this system, a balance sequence (BS) is inserted in the information bits. The BS can be determined by exhaustive search in the encoding process. But when the length of the BS is long, the time of searching may increase exponentially with the length and it is not practical for the hardware implementation. Thus a low complexity method to dynamically determine the BS is proposed, which uses A periodic autocorrelation function (AAF) as the metric, and is shown in this paper , Simulation results show that this method can reduce the PAPR of this system effectively.