发表机构
Trinity College Dublin; University of Essex（都柏林三一学院; 埃塞克斯大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对AFDM现有信道参数估计方法导频开销大或计算复杂的问题，本文利用其移位特性与输入输出关系，提出一种低开销、无网格搜索的脉冲导频估计方法，结合SIC框架实现多径信道参数估计，性能优于基准方法。
AI 中文摘要
仿射频分复用（AFDM）因具备出色的后向兼容性、可实现的全分集，以及对高多普勒频移和各类硬件损伤的强鲁棒性，已受到广泛关注。然而，现有的AFDM信道参数估计方法要么需要大量导频开销，要么依赖计算密集型的网格搜索方法。本文提出一种不依赖网格搜索、低导频开销、基于脉冲导频的AFDM系统信道参数估计方法，利用其固有的移位特性。具体而言，我们证明多普勒频移对脉冲导频的影响等价于时域中带有相位旋转的时延移位；此外，时延和多普勒频移都会导致仿射域中的循环移位。通过利用时域和仿射域的这些特性，可构建两个线性方程以估计每条路径的整数时延和多普勒频移。多普勒的小数部分则通过利用AFDM输入输出关系，从脉冲导频周围由多普勒引起的泄漏中估计得到。对于多径信道，本文开发了一个串行干扰消除（SIC）框架，其中首先估计最强的传播路径，对其进行重构并消除，之后再依次估计剩余路径。仿真结果表明，所提方法相比基准方法显著降低了计算复杂度，且允许更低的导频开销，同时所提方法还实现了更优的信道参数估计性能。
英文摘要
Affine frequency division multiplexing (AFDM) has attracted significant attention owing to its excellent backwards compatibility, full diversity achievability, as well as strong resilience to high Doppler and various hardware impairments. Existing AFDM channel parameter estimation methods, however, either require large pilot overhead or rely on computationally intensive grid search methods. This paper proposes a grid-search-independent, low-overhead, impulse-pilot-based channel parameter estimation method for AFDM systems by exploiting its inherent shift properties. Specifically, we show that the effect of a Doppler shift on the impulse pilot is equivalent to a delay shift in the time domain with a phase rotation. Additionally, both delay and Doppler shifts lead to cyclic shifts in the affine domain. By utilizing these properties in both the time and affine domains, two linear equations are formed to estimate the integer delay and Doppler of each path. The fractional part of the Doppler is estimated from the Doppler-induced leakage around the impulse pilot by exploiting the AFDM input-output relationship. For multipath channels, a successive interference cancellation (SIC) framework is developed, in which the strongest propagation path is first estimated, reconstructed, and canceled before the remaining paths are successively estimated. Simulation results demonstrate that the proposed method significantly reduces computational complexity and allows lower pilot overhead than the benchmarks. The proposed method also achieves improved channel parameter estimation and
