Affine frequency division multiplexing (AFDM) is a promising new multicarrier technique for high-mobility communications based on discrete affine Fourier transform (DAFT). By properly tuning the pre-chirp parameter and the post-chirp parameter in the DAFT, the effective channel in the DAFT domain can completely circumvent path overlap, thereby constituting a full representation of delay-Doppler profile. However, AFDM has a crucial problem of high peak-to-average power ratio (PAPR), stemming from randomness of modulated symbols. In this letter, a novel algorithm named grouped pre-chirp selection (GPS) is proposed to reduce PAPR by strategically varying the pre-chirp parameter across subcarrier groups. Initially, it is established that key AFDM properties are maintained when implementing GPS. Next, we proceed to detail the operational procedures of the GPS algorithm, elucidating its principle for PAPR reduction and emphasizing its computational efficiency advantages. Finally, simulation results employing the complementary cumulative distribution function (CCDF) validate the effectiveness of the proposed GPS in reducing PAPR.

翻译：仿射频分复用（AFDM）是一种基于离散仿射傅里叶变换（DAFT）的、适用于高移动性通信的新型多载波技术。通过适当调整DAFT中的预啁啾参数和后啁啾参数，DAFT域中的有效信道可以完全避免路径重叠，从而构成时延-多普勒剖面的完整表示。然而，AFDM存在一个关键问题，即由于调制符号的随机性导致高峰均功率比（PAPR）。本文提出了一种名为分组预啁啾选择（GPS）的新算法，通过策略性地改变不同子载波组的预啁啾参数来降低PAPR。首先，我们证明了在实施GPS时，AFDM的关键特性得以保持。接着，我们详细阐述了GPS算法的操作流程，阐明了其降低PAPR的原理，并强调了其计算效率优势。最后，采用互补累积分布函数（CCDF）的仿真结果验证了所提出的GPS算法在降低PAPR方面的有效性。