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arXiv 2602.20909eess.SP
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AFDM的连续时间分析:脉冲成型、基本界限及硬件失真影响

Continuous-Time Analysis of AFDM: Pulse-Shaping, Fundamental Bounds and Impact of Hardware Impairments

University of Modena and Reggio Emilia(摩德纳和雷焦艾米利亚大学);Constructor University(康斯特鲁克托大学)

Michele Mirabella, Hyeon Seok Rou, Pasquale Di Viesti, Giuseppe Thadeu Freitas de Abreu, Giorgio Matteo Vitetta

AI总结:

本文提出基于仿射傅里叶级数的连续时间分析框架,揭示了AFDM中严格带限脉冲和子载波抑制策略的重要性,并推导了其功率谱密度及信道参数估计的Cramér-Rao界限,展示了AFDM在多普勒模糊问题上的独特优势。

摘要:

仿射频率分复用(AFDM)最近已成为高机动性下一代无线系统中具有韧性的波形候选者。然而,当前文献大多集中在离散时间(DT)模型上,往往忽略了实际连续时间(CT)信号生成中的影响和非理想硬件因素。在本文中,我们通过基于仿射傅里叶级数(AFS)表示的CT分析框架来填补这一空白,使我们能够证明严格带限脉冲和子载波抑制策略对于保持传输信号的多载波结构至关重要。此外,我们推导了AFDM的分析功率谱密度,并将其频谱特性与其他多载波方案进行比较,考虑了实际截断脉冲成型的影响。此外,我们分析了CT模型对相位噪声、载波频率偏移和采样抖动的敏感性,提供了通信性能的理论分析。最后,我们推导了信道参数估计的闭式Cramér-Rao界限,表明AFDM特有的拍频调制增加了估计方差,但能够解决多普勒模糊问题。我们的发现为在现实无线收发器中实现AFDM奠定了必要的理论和实际基础。

英文摘要:

Affine frequency division multiplexing (AFDM) has recently emerged as a resilient waveform candidate for high-mobility next-generation wireless systems. However, current literature mostly focuses on discrete time (DT) models, often overlooking effects and hardware non-idealities of actual continuous time (CT) signal generation. In this paper, we bridge this gap by developing a CT-analytical framework based on the affine Fourier series (AFS) representation, which allows us to demonstrate that strictly bandlimited pulses and subcarrier suppression strategies are essential to maintain the multicarrier structure of the transmitted signal. In addition, we derive the analytical power spectral density of AFDM and compare its spectral characteristics in comparison with those of other multicarrier schemes, taking into account the impact of realistic truncated pulse-shaping. Furthermore, we analyze the sensitivity of the CT model to phase noise, carrier frequency offset, and sampling jitter, providing a theoretical analysis of communication performance. Finally, we derive closed-form Cramér-Rao bounds for channel parameter estimation, showing that the chirped modulation peculiar of AFDM increases estimation variance but enables the resolution of Doppler ambiguities. Our findings lay the necessary theoretical and practical foundations for the implementation of AFDM in realistic wireless transceivers.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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