发表机构
Federal University of Technology – Paraná; Constructor University（巴拉那联邦理工大学; 康斯特大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究针对DAFT-s-AFDM上行链路，分析残余啁啾率对PAPR和BER的影响，发现一般速率可显著降低误码率所需信噪比，但需权衡PAPR代价。
AI 中文摘要
仿射频分复用（AFDM）在高移动性6G系统中对双色散信道具有鲁棒性，但与正交频分复用（OFDM）一样，存在高峰均功率比（PAPR）问题。通过离散仿射傅里叶变换（DAFT）进行扩频得到DAFT-s-AFDM，其预编码器和调制器的啁啾可以独立选择。对于采用零偏移局部分配的单用户，我们证明这两个啁啾合并为一个残余啁啾，在其他两个啁啾率固定的情况下，该残余啁啾的速率单独决定其影响。在发射端，该速率定义了一个循环扩频核，其四阶矩量化了包络波动；对称性将其表征简化为[0, 1/4]范围内的速率。在线性最小均方误差（MMSE）接收机处，残余啁啾在符号间重新分配均方误差而不改变其总和；在高斯近似下，更均匀的每符号误差降低了未编码的误比特率（BER）。在未编码QPSK仿真中，零速率产生最低的PAPR，而一般速率在3.33 dB PAPR代价（超越概率10^{-3}）下，将BER为10^{-3}所需的信噪比降低了4.4 dB；1/3的速率仅以0.88 dB的代价捕获了该增益中的2.8 dB。
英文摘要
Affine frequency division multiplexing (AFDM) is robust to doubly dispersive channels in high-mobility 6G systems but, like orthogonal frequency division multiplexing (OFDM), suffers from a high peak-to-average power ratio (PAPR). Spreading with a discrete affine Fourier transform (DAFT) yields DAFT-s-AFDM, whose precoder and modulator chirps can be chosen independently. For a single user with zero-offset localized allocation, we show that these two chirps merge into a single residual chirp whose rate, with the other two chirp rates fixed, alone determines their effect. At the transmitter, this rate defines a circulant spreading kernel whose fourth moment quantifies the envelope fluctuation; symmetries reduce its characterization to rates in [0, 1/4]. At a linear minimum mean-square error (MMSE) receiver, the residual chirp redistributes the mean- square error across symbols without changing its total; under a Gaussian approximation, a more uniform per-symbol error lowers the uncoded bit error rate (BER). In uncoded QPSK simulations, a zero rate yields the lowest PAPR, whereas a generic rate reduces the signal-to-noise ratio required for a BER of $10^{-3}$ by 4.4 dB at a 3.33 dB PAPR cost (exceedance probability $10^{-3}$);a rate of 1/3 captures 2.8 dB of this gain for only 0.88 dB of that cost.
