Optimized Gradient Projection for PAPR reduction of OFDM signals

In this paper, a new Optimized Gradient Projection (OGP) algorithm is proposed based on Partial Transmit Sequence (PTS) and Active Constellation Extension (ACE) algorithm to reduce Peak-to-Average Power Ratio (PAPR) in Orthogonal Frequency Division Multiplexing (OFDM) system. The improved PTS algorithm using Linear Search Iterative Shift (LSIS) selects the sequence with lowest PAPR to transmit. The output signal of LSIS PTS is set as the input signal of ACE algorithm. ACE uses Gradient Projection (GP) algorithm to reduce the PAPR. A pre-clipping vector in ACE is proposed to decrease the computation. Simulation results show that OGP algorithm can attain a sharp drop of CCDF curve and reduce PAPR to an acceptable level with lower computation complexity.