An Improved Method for Reducing PAPR Based on SLM Method in OCDM System

With the increasing demands for higher data transmission rates and spectral efficiency in modern wireless communication systems, a growing number of advanced modulation techniques have been developed. Orthogonal chirp division multiplexing (OCDM), as an emerging modulation technique, possesses enormous application prospects with its excellent antiinterference performance and high spectral utilization, especially in high-speed communications and complex channel environments. However, a significant challenge in the practical implementation of the OCDM system is its inherently high peak-toaverage power ratio (PAPR). Excessive PAPR not only leads to nonlinear distortion of the power amplifier, but also may reduce the energy efficiency, increase the bit error ratio (BER), and ultimately affect the overall performance. Accordingly, this paper proposes a novel PAPR suppression method based on conventional selective mapping (SLM), called A-law selective mapping (A-SLM). In the proposed method, multiple candidate signals are first generated using the SLM transformation. The signal with the lowest PAPR is then selected for transmission, followed by amplitude balancing through the A-law companding technique. This approach results in a substantial reduction in PAPR. Simulation results demonstrate that the OCDM system employing the A-SLM method achieves approximately a 6 dB reduction in PAPR compared to the conventional OCDM system.