Partial Transmit Sequences Based on Multi-Loop search method

High peak-to-average power ratio (PAPR) is the main drawback of the OFDM signal, which increases the ODFM system’s nonlinear distortion. Partial transmit sequences (PTS) is one of the most attractive schemes to reduce the PAPR in orthogonal frequency division multiplexing systems (OFDM). However, the optimum PTS scheme requires an exhaustive searching over all combinations of allowed phase factors to obtain the optimal phase factors combination and this result in high computational complexity. What’s worse, the computational complexity increases exponentially with the number of sub-blocks. Consequently, the PTS scheme is not applicable in practical applications. In this paper, we propose a novel multi-loop comparison scheme with low computational complexity. In the proposed method, the optimum phase factor combination of allowed phase factors is achieved by the method of multi-loop comparison instead of exhaustive searching. The multi-loop comparison scheme can help to skip some redundant computing and avoid being trapped in local optima. The performance analysis shows that multi-loop comparison PTS can reduce the computational complexity dramatically while achieve almost the same PAPR reduction performance compared to optimum PTS.