In recent years, neural networks have been used to solve phase retrieval
problems in imaging with superior accuracy and speed than traditional
techniques, especially in the presence of noise. However, in the context of
interferometric imaging, phase noise has been largely unaddressed by existing
neural network architectures. Such noise arises naturally in an interferometer
due to mechanical instabilities or atmospheric turbulence, limiting measurement
acquisition times and posing a challenge in scenarios with limited light
intensity, such as remote sensing. Here, we introduce a 3D-2D Phase Retrieval
U-Net (PRUNe) that takes noisy and randomly phase-shifted interferograms as
inputs, and outputs a single 2D phase image. A 3D downsampling convolutional
encoder captures correlations within and between frames to produce a 2D latent
space, which is upsampled by a 2D decoder into a phase image. We test our model
against a state-of-the-art singular value decomposition algorithm and find
PRUNe reconstructions consistently show more accurate and smooth
reconstructions, with a x2.5 - 4 lower mean squared error at multiple
signal-to-noise ratios for interferograms with low (< 1 photon/pixel) and high
(~100 photons/pixel) signal intensity. Our model presents a faster and more
accurate approach to perform phase retrieval in extremely low light intensity
interferometry in presence of phase noise, and will find application in other
multi-frame noisy imaging techniques.

近年来，神经网络已被用于解决成像中的相位恢复问题，比传统技术具有更高的准确性和速度，特别是在存在噪声的情况下。然而，在干涉成像的背景下，现有的神经网络结构很少解决相位噪声问题。本文介绍了一种 3D-2D 相位恢复 U-Net (PRUNe) 模型，它以噪声和随机相位移的干涉图作为输入，并输出一张 2D 相位图像。经过 3D 降采样卷积编码器和 2D 解码器的处理，模型能更准确、平滑地恢复相位图像，在低光强（<1 个光子 / 像素）和高光强（~100 个光子 / 像素）信噪比的干涉图像上，均表现出比现有算法更低 2.5-4 倍的均方误差。该模型为在极低光强干涉成像中进行相位恢复提供了更快速和更准确的方法，并将在其他多帧噪声成像技术中应用。

噪声干扰下干涉成像相位恢复的 3D-2D 神经网络

3D-2D Neural Nets for Phase Retrieval in Noisy Interferometric Imaging

In this paper, we derive the uplink achievable rate expression of intelligent
reflecting surface (IRS)-aided millimeter-wave (mmWave) systems, taking into
account the phase noise at IRS and the quantization error at base stations
(BSs). We show that the performance is limited only by the resolution of
analog-digital converters (ADCs) at BSs when the number of IRS reflectors grows
without bound. On the other hand, if BSs have ideal ADCs, the performance loss
caused by IRS phase noise is a constant. Finally, our results validate the
feasibility of using low-precision hardware at the IRS when BSs are equipped
with low-resolution ADCs.

本文研究了智能反射面辅助毫米波系统的上行可达速率表达式，考虑了智能反射面的相位噪声和基站（BS）的量化误差，结果表明当智能反射面的反射器数量趋近无限时，性能仅受到 BS 模数转换器分辨率的限制；另一方面，如果 BS 具有理想的 ADC，则智能反射面相位噪声导致的性能损失是恒定的；最后，研究结果验证当 BS 装备低分辨率 ADC 时，智能反射面可以使用低精度硬件实现。

低分辨率 ADC 与相位噪声下智能反射面辅助毫米波通信的上行可达速率

Uplink Achievable Rate of Intelligent Reflecting Surface-Aided  Millimeter-Wave Communications with Low-Resolution ADC and Phase Noise

Recent works have identified massive multiple-input-multiple-output (MIMO) as
a key technology for achieving substantial gains in spectral and energy
efficiency. Additionally, the turn to low-cost transceivers, being prone to
hardware impairments is the most effective and attractive way for
cost-efficient applications concerning massive MIMO systems. In this context,
the impact of channel aging, which severely affects the performance, is
investigated herein by considering a generalized model. Specifically, we show
that both Doppler shift because of the users' relative movement as well as
phase noise due to noisy local oscillators (LOs) contribute to channel aging.
To this end, we first propose a joint model, encompassing both effects, in
order to investigate the performance of a massive MIMO system based on the
inevitable time-varying nature of realistic mobile communications. Then, we
derive the deterministic equivalents (DEs) for the
signal-to-noise-and-interference ratios (SINRs) with maximum ratio transmission
(MRT) and regularized zero-forcing precoding (RZF). Our analysis not only
demonstrates a performance comparison between MRT and RZF under these
conditions, but most importantly, it reveals interesting properties regarding
the effects of user mobility and phase noise. In particular, the large antenna
limit behavior depends profoundly on both effects, but the burden due to user
mobility is much more detrimental than phase noise even for moderate user
velocities ($\approx30$ km/h), while the negative impact of phase noise is
noteworthy at lower mobility conditions.

本文研究了基于低成本收发器的大规模 MIMO 系统中信道老化问题，并通过提出联合模型，分析了 Doppler 频移和本地振荡器相位噪声对信道老化问题的影响。在此基础上，作者进一步推导出使用最大比传输和正则化零强制预编码的信干噪比确定等效情况下，这两种传输策略的性能比较，并探讨了用户移动性和本地振荡器相位噪声对大规模 MIMO 系统影响的差异。