突发脉冲噪声下OFDM系统频域NSI的统计特性与块EM估计
Statistical Characterization and Block-EM Estimation of Frequency-Domain NSI for OFDM Systems in Bursty Impulsive Noise
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中文总结 AI 辅助
针对突发脉冲噪声下OFDM系统时域IN抑制技术的局限，提出频域块框架，推导IN频域统计模型，开发NSI估计的EM框架及变体，实现性能提升且复杂度更低。
中文摘要 AI 辅助
脉冲噪声（IN）具有高功率和非高斯分布的特征，随着电子设备的普及，对现代正交频分复用（OFDM）系统构成了关键挑战。当前的IN抑制技术严重依赖时域处理，这些方法在离散傅里叶变换（DFT）之前应用，会引入额外复杂度，不符合OFDM固有的频域处理流程，且因IN消除不完善而存在破坏子载波正交性的风险。为解决这些局限，本文提出一种基于块的频域IN抑制框架：首先通过变换高斯混合模型推导IN在频域的统计表示；基于该模型，开发利用完美噪声状态信息（NSI）的最优接收机，从而明确NSI起关键作用的场景；随后提出一种无监督的基于块的期望最大化（EM）框架用于NSI估计，并开发三个变体用于评估，包括简单的逐符号方差更新EM、基于序列的转移更新EM，以及利用促进稀疏性的先验自动修剪状态数的MAP-based EM。本文的频域设计在DFT之后运行，与OFDM处理链无缝集成，保留子载波正交性，并利用已知的IN块结构实现显著性能提升，且无需时域脉冲重构的巨大复杂度。
英文摘要
Impulsive noise (IN), characterized by its high power and non-Gaussian distribution, poses a critical challenge in modern orthogonal frequency-division multiplexing (OFDM) systems, driven by the proliferation of electronic devices. Current IN mitigation techniques rely heavily on time-domain processing. These methods are applied before the discrete Fourier transform (DFT), introducing additional complexity, failing to align with OFDM's inherent frequency-domain processing flow, and risking the destruction of subcarrier orthogonality due to imperfect IN subtraction. To address these limitations, we propose a frequency-domain, block-based framework for mitigating IN. The statistical representation of IN in the frequency domain is first derived using a transformed Gaussian mixture model. Based on this model, we develop an optimal receiver that leverages perfect noise state information (NSI), thereby identifying scenarios in which NSI is critical. We then propose an unsupervised block-based expectation-maximization (EM) framework for NSI estimation and develop three variants for evaluation. These include a simple symbol-by-symbol variance-updated EM, a sequence-based transition-updated EM, and a MAP-based EM that exploits a sparsity-promoting prior to automatically prune the number of states. Our frequency-domain design operates after the DFT, seamlessly integrates with the OFDM processing chain, preserves subcarrier orthogonality, and leverages the known IN block structure to achieve substantial performance gains without the immense complexity of time-domain impulse reconstruction.
发表机构
- Eindhoven University of Technology（埃因霍温理工大学）
- NXP Semiconductors（恩智浦半导体）
机构由 AI 辅助整理，请以论文原文为准。
