results: 研究发现在 PM-stirred RC 中可以实现多种 Rico 折射通道的模拟，但是存在一定的限制，包括可控 K-factor 的Upper bound和 Lower bound。Abstract
We experimentally investigate the feasibility of evaluating multiple-input multiple-output (MIMO) radio equipment under adjustable Rician fading channel conditions in a programmable-metasurface-stirred (PM-stirred) reverberation chamber (RC). Whereas within the "smart radio environment" paradigm PMs offer partial control over the channels to the wireless system, in our use case the PM emulates the uncontrollable fading. We implement a desired Rician K-factor by sweeping a suitably sized subset of all meta-atoms through random configurations. We discover in our setup an upper bound on the accessible K-factors for which the statistics of the channel coefficient distributions closely follow the sought-after Rician distribution. We also discover a lower bound on the accessible K-factors in our setup: there are unstirred paths that never encounter the PM, and paths that encounter the PM are not fully stirred because the average of the meta-atoms' accessible polarizability values is not zero (i.e., the meta-atoms have a non-zero "structural" cross-section). We corroborate these findings with experiments in an anechoic chamber, physics-compliant PhysFad simulations with Lorentzian vs "ideal" meta-atoms, and theoretical analysis. Our work clarifies the scope of applicability of PM-stirred RCs for MIMO Rician channel emulation, as well as electromagnetic compatibility test.
摘要
我们实验性地探索了多输入多输出（MIMO）无线设备在可调 rician 折射通道条件下的可能性。在“智能无线环境”概念下，PM 提供了对无线系统的部分控制权，但在我们的使用情况下，PM 模拟了不可控的折射。我们通过逐渐变换一个合适的子集的所有元件来实现所需的 rician K 因子。我们发现在我们的设置中，可达的 K 因子的上限，channel coefficient 分布 Statistics 几乎与目标 rician 分布一致。我们还发现了可达的 K 因子下界：有些不扰urbed 路径从来不会遇到 PM，而其他路径只是部分扰urbed，因为元件的可访问 polarizability 值的平均值不为零（即元件有非零“结构”交叉section）。我们通过实验室、PhysFad simulations 和理论分析证明了这些发现。我们的工作解释了 PM-stirred RC 在 MIMO rician 通道模拟和电磁兼容测试中的可行范围。
Adversarial Attacks and Defenses for Wireless Signal Classifiers using CDI-aware GANs
results: 在攻击场景下，CDI-aware GAN 展现了其强大的攻击能力，将目标分类器欺骗成功，较进一步的方法超越。此外，CDI-aware GAN 作为一个守备者，可以对目标分类器提供额外的保护，很大提高了这个分类器对攻击的抵抗力。Abstract
We introduce a Channel Distribution Information (CDI)-aware Generative Adversarial Network (GAN), designed to address the unique challenges of adversarial attacks in wireless communication systems. The generator in this CDI-aware GAN maps random input noise to the feature space, generating perturbations intended to deceive a target modulation classifier. Its discriminators play a dual role: one enforces that the perturbations follow a Gaussian distribution, making them indistinguishable from Gaussian noise, while the other ensures these perturbations account for realistic channel effects and resemble no-channel perturbations. Our proposed CDI-aware GAN can be used as an attacker and a defender. In attack scenarios, the CDI-aware GAN demonstrates its prowess by generating robust adversarial perturbations that effectively deceive the target classifier, outperforming known methods. Furthermore, CDI-aware GAN as a defender significantly improves the target classifier's resilience against adversarial attacks.
摘要
我们介绍一个频道分布信息（CDI）意识的生成对抗网络（GAN），用于解决无线通信系统中的特有攻击挑战。 generator这个CDI-aware GAN将随机输入噪声映射到特征空间，生成欺骗目标模式分类器的干扰。它的检测器扮演双重角色：一方是保持干扰遵循 Gaussian 分布，使其与随机噪声无法区别，另一方是确保这些干扰具有实际通道效应，与无通道干扰无法区别。我们的提议的CDI-aware GAN可以作为攻击者和防御者使用。在攻击场景中，CDI-aware GAN demonstrates its prowess by generating robust adversarial perturbations that effectively deceive the target classifier, outperforming known methods. 在防御场景中，CDI-aware GAN 作为防御者，对目标分类器的抗攻击能力提供了重大改善。
Performance Analysis of Integrated Sensing and Communications Under Gain-Phase Imperfections
paper_authors: Shuaishuai Han, Mohammad Ahmad Al-Jarrah, Emad Alsusa
for: 本研究评估了无人飞机传输数据的紧 Integrated Sensing and Communication 系统在 gain 和 phase 偏差的情况下的性能。
methods: 本研究使用了 maximum likelihood 算法 для地理位置 estimation，并对 signal parameters 的估计进行了比较。
results: 研究发现， gain 和 phase 偏差对 both localization 和 communication 有显著的影响，但提出的 maximum likelihood 算法比其他算法更为敏感。 I hope that helps! Let me know if you have any other questions.Abstract
This paper evaluates the performance of uplink integrated sensing and communication systems in the presence of gain and phase imperfections. Specifically, we consider multiple unmanned aerial vehicles (UAVs) transmitting data to a multiple-input-multiple-output base-station (BS) that is responsible for estimating the transmitted information in addition to localising the transmitting UAVs. The signal processing at the BS is divided into two consecutive stages: localisation and communication. A maximum likelihood (ML) algorithm is introduced for the localisation stage to jointly estimate the azimuth-elevation angles and Doppler frequency of the UAVs under gain-phase defects, which are then compared to the estimation of signal parameters via rotational invariance techniques (ESPRIT) and multiple signal classification (MUSIC). Furthermore, the Cramer-Rao lower bound (CRLB) is derived to evaluate the asymptotic performance and quantify the influence of the gain-phase imperfections which are modelled using Rician and von Mises distributions, respectively. Thereafter, in the communication stage, the location parameters estimated in the first stage are employed to estimate the communication channels which are fed into a maximum ratio combiner to preprocess the received communication signal. An accurate closed-form approximation of the achievable average sum data rate (SDR) for all UAVs is derived. The obtained results show that gain-phase imperfections have a significant influence on both localisation and communication, however, the proposed ML is less sensitive when compared to other algorithms. The derived analysis is concurred with simulations.
摘要
Translation:这篇论文评估了无人飞行器（UAV）在干扰环境下的下降整合感知通信系统的性能。特别是，我们考虑多个UAV发送数据到一个多输入多输出基站（BS），BS负责估计传输信息以及地理位置的UAV。信号处理在BS中分为两个阶段：地理位置和通信。我们引入了最大可能性（ML）算法来实现地理位置阶段，并同时估计UAV的方位角和Doppler频率。然后，我们对ESPRIT和MUSIC等技术进行比较。此外，我们还 deriv了Cramer-Rao下界（CRLB）来评估干扰环境的极限性能，并量化干扰环境中 gain-phase 的影响。接着，在通信阶段，地理位置参数估计在第一个阶段中被用来估计通信 кана径，然后通过最大比例组合器进行前处理。我们 deriv了所有UAV的可行的均值总数据率（SDR）的准确闭合式表达。结果显示，干扰环境中 gain-phase 的影响是非常大，但是我们提出的ML算法对其他算法比较敏感。我们的分析与实验结果相符。
OISA: Architecting an Optical In-Sensor Accelerator for Efficient Visual Computing
results: OISA可以在不同的图像数据集上达到可接受的准确性，并在电子内部/近端和ASIC加速器中降低了平均电力消耗量 by 7.9和18.4倍。Abstract
Targeting vision applications at the edge, in this work, we systematically explore and propose a high-performance and energy-efficient Optical In-Sensor Accelerator architecture called OISA for the first time. Taking advantage of the promising efficiency of photonic devices, the OISA intrinsically implements a coarse-grained convolution operation on the input frames in an innovative minimum-conversion fashion in low-bit-width neural networks. Such a design remarkably reduces the power consumption of data conversion, transmission, and processing in the conventional cloud-centric architecture as well as recently-presented edge accelerators. Our device-to-architecture simulation results on various image data-sets demonstrate acceptable accuracy while OISA achieves 6.68 TOp/s/W efficiency. OISA reduces power consumption by a factor of 7.9 and 18.4 on average compared with existing electronic in-/near-sensor and ASIC accelerators.
摘要
targeting 视频应用程序的边缘部署，在这项工作中，我们系统地探索并提出了一种高性能且能效的光学内部加速器架构，称为OISA。通过利用光电设备的潜在高效性，OISA内置了一种粗粒度卷积操作，对输入帧进行 minimum-conversion 的实现。这种设计突出 reductions 数据转换、传输和处理的能量消耗，在云端-центри的架构以及最近提出的边缘加速器中。我们的设备-到-架构仿真结果表明，OISA可以实现 Acceptable 准确性，同时达到 6.68 TOp/s/W 的效率。相比之下，OISA 在电子内部/近端和ASIC加速器方面减少了平均的能量消耗量为 7.9 和 18.4。
Robust-to-Noise Algorithms for Distributed Resource Allocation and Scheduling
results: 本文的研究结果显示，这种新的robust资源分配和计划算法可以在不同的网络环境下适应噪音和干扰，并且可以维持资源需求的均衡和网络组态的可行性。同时，本文还考虑了不同网络环境下的均衡网络和多样网络条件。Abstract
Efficient resource allocation and scheduling algorithms are essential for various distributed applications, ranging from wireless networks and cloud computing platforms to autonomous multi-agent systems and swarm robotic networks. However, real-world environments are often plagued by uncertainties and noise, leading to sub-optimal performance and increased vulnerability of traditional algorithms. This paper addresses the challenge of robust resource allocation and scheduling in the presence of noise and disturbances. The proposed study introduces a novel sign-based dynamics for developing robust-to-noise algorithms distributed over a multi-agent network that can adaptively handle external disturbances. Leveraging concepts from convex optimization theory, control theory, and network science the framework establishes a principled approach to design algorithms that can maintain key properties such as resource-demand balance and constraint feasibility. Meanwhile, notions of uniform-connectivity and versatile networking conditions are also addressed.
摘要
efficient resource allocation and scheduling algorithms are essential for various distributed applications, ranging from wireless networks and cloud computing platforms to autonomous multi-agent systems and swarm robotic networks. However, real-world environments are often plagued by uncertainties and noise, leading to sub-optimal performance and increased vulnerability of traditional algorithms. This paper addresses the challenge of robust resource allocation and scheduling in the presence of noise and disturbances. The proposed study introduces a novel sign-based dynamics for developing robust-to-noise algorithms distributed over a multi-agent network that can adaptively handle external disturbances. 抽象：* 多 Agent 系统和分布式应用需要高效的资源分配和调度算法，从无线网络和云计算平台到自主多 агент系统和群体机器人网络。* 实际环境受到不确定性和噪声的影响，导致传统算法的低效性和投降。* 本文挑战了在噪声和干扰下的资源分配和调度问题。* 提出了一种基于签名动力学的多 Agent 网络中的强健性调度算法，可以适应外部干扰。* 利用了 convex 优化理论、控制理论和网络科学，提出了一种原则性的方法，可以保持资源需求均衡和约束可行性。* 同时，也考虑了一致连接和多样网络条件。
A New Old Idea: Beam-Steering Reflectarrays for Efficient Sub-THz Multiuser MIMO
paper_authors: Krishan Kumar Tiwari, Giuseppe Caire
for: 这个论文是为了解决多用户多束 Reflective Intelligent Surface（RIS）架构在多用户MIMO中的问题，尤其是在高频率band（例如高mmWave和sub-THz）中， channels Typically sparse in the beamspace and LOS is the dominant component.
results: 研究人员通过分析了多用户之间的干扰和AMAF-RIS结构中的频率选择性的效果，并证明了“束定 beam”是在远场也可以实现的，并且可以创造有限的角度和距离射频谱的spotbeams。研究结果表明：1）简单的RF扫描（BF）无需计算expensive的基带多用户预测可以实际消除多用户干扰；2）RIS量化相位调制器的影响是可以忽略不计；3）提posed architecture是传统活动数组的硬件实现和功率管理方面更加高效和简单。Abstract
We present a novel, power- & hardware-efficient, multiuser, multibeam RIS (Reflective Intelligent Surface) architecture for multiuser MIMO, especially for very high frequency bands (e.g., high mmWave and sub-THz), where channels are typically sparse in the beamspace and LOS is the dominant component. The key module is formed by an active multiantenna feeder (AMAF) with a small number of active antennas, placed in the near field of a RIS with a much larger number of passive controllable reflecting elements. We propose a pragmatic approach to obtain a steerable beam with high gain and very low sidelobes. Then K independently controlled beams can be achieved by closely stacking K such AMAF-RIS modules. Our analysis includes the mutual interference between the modules and the fact that, due to the delay difference of propagation through the AMAF-RIS structure, the resulting channel matrix is frequency selective even for pure LOS propagation. We consider a 3D geometry and show that "beam focusing" is in fact possible (and much more effective in terms of coverage) also in the far-field, by creating spotbeams with limited footprint both in angle and in range. Our results show that: 1) simple RF beamforming (BF) without computationally expensive baseband multiuser precoding is sufficient to practically eliminate multiuser interference when the users are chosen with sufficient angular/range separation, thanks to the extremely low sidelobe beams; 2) the impact of beam pointing errors with standard deviation as large as 2.5 deg and RIS quantized phase-shifters with quantization bits > 2 is essentially negligible; 3) The proposed architecture is more power efficient & much simpler from a hardware implementation viewpoint than standard active arrays with the same BF performance. We show also that the array gain of the proposed AMAF-RIS structure is linear with the RIS aperture.
摘要
我们提出了一种新的、功率和硬件效率高的多用户多束反射智能表面（RIS）架构，特别适用于高频范围内（例如高 millimeter 波和子teraHz）， где каналы通常是在束空间 sparse 的和直接射线（LOS）是主要组成部分。关键模块由一个活动多天线发食（AMAF）组成，该发食具有小数量的活动天线，位于RIS附近的多个可控制的反射元件中。我们提议一种实用的方法，以实现高得分和很低的侧obeams。然后，可以通过密集排列K个AMAF-RIS模块来实现K独立控制的束。我们的分析包括模块之间的干扰和因为AMAF-RIS结构的延迟差而导致的频率选择性的通道矩阵。我们考虑3D几何结构，并证明了"束注入"实际上也是可行的（并且在远场更有效），通过创建有限footprint的点束，以限制角度和距离方向的覆盖。我们的结果表明：1）使用简单的RF扩散（BF）无需 computationally expensive的基带多用户预测，可以实际消除多用户干扰，因为束空间的低侧obeams; 2）RIS量化相位调制器的标准偏移量为2.5度以上，对束注入的影响是 praktisch 可以忽略的; 3）提议的架构比标准活动数组更有效率和更简单的硬件实现。我们还证明了AMAF-RIS结构的面积 linear 相关的数组增益。
results: 比较Result show that the proposed scheme outperforms benchmark schemes in terms of error rate performance, especially in systems with a larger number of receive antennas. In the special case where each receive antenna corresponds to a user and is activated, the RIS-GRQSM system becomes a multicast communication system, and the proposed solution offers low complexity and practical feasibility of implementation.Abstract
In this paper, reconfigurable intelligent surface (RIS)-assisted generalized receive quadrature spatial modulation (RIS-GRQSM) is proposed to improve the spectral efficiency of RIS-aided quadrature spatial modulation (QSM) systems by utilizing the concept of generalized spatial modulation (GSM). That is, multiple antennas are activated at the receiver independently for both the real and imaginary parts. We propose a max-min optimization problem to adjust the phase shifts of all RIS elements to maximize the relevant signal-to-noise ratios (SNRs) at all activated receive antennas. Using Lagrange duality, the non-convex optimization problem involving the phase shifts of all RIS elements reduces to a convex optimization involving a number of variables equal to the number of activated receive antennas. A successive greedy detector (GD) can be used at the receiver to detect the active antennas, which simplifies the detection process. The numerical results show that the proposed scheme outperforms the benchmark schemes in terms of error rate performance, especially in systems with a larger number of receive antennas. In the special case where each receive antenna corresponds to a user and is activated, the RIS-GRQSM system becomes a multicast communication system. In this context, in contrast to existing phase shift optimization algorithms which exhibit an impractical level of complexity, our proposed solution offers the advantage of low complexity and practical feasibility of implementation.
摘要
在这篇论文中，我们提出了基于扩展受信道模式（GSM）的 receive quadrature spatial modulation（RIS-GRQSM），用于提高RIS受器受控 quadrature spatial modulation（QSM）系统的spectral efficiency。具体来说，在接收器端，多个天线被独立地活动，以处理实部和虚部的两部分。我们提出了一个最大化相关信号听号比（SNR）的最小化问题，以调整所有RIS元素的阶段偏移。使用拉格朗日熊束，非 convex 优化问题转化为一个 convex 优化问题，其中变量数等于活动接收天线的数量。接收器端可以使用成功的恰遇探测器（GD）检测活动天线，从而简化检测过程。实验结果表明，提议的方案在错误率性能方面比参照方案更高，特别是在系统中有更多的接收天线时。在特殊情况下，每个接收天线对应一个用户，并且被活动，则RIS-GRQSM系统变为一个多播通信系统。在这种情况下，与现有阶段偏移优化算法不同，我们的提议的解决方案具有低复杂度和实际可行的实施问题。
paper_authors: E. O. Olateju, K. P. Ayodele, S. K. Mosaku
For: The paper aims to improve the scarcity of high-quality EEG datasets for schizophrenia diagnostic tools development and studies, specifically from populations of developing and underdeveloped regions of the world.* Methods: The paper presents an EEG dataset of international 10/20 system recordings from West African subjects of Nigerian origin, including resting conditions, mental arithmetic task execution, and passive auditory stimuli reactivity. The dataset includes 36 cases and 21 healthy controls, identified using the Mini International Schizophrenia Interview (MINI) and assessed by the Positive and Negative Symptoms Scale (PANSS) and the World Health Organization Disability Assessment Schedule (WHODAS).* Results: The dataset can be used by the neuroscience and computational psychiatry research community studying the diagnosis and prognosis of schizophrenia using the electroencephalogram signal modality.Here is the information in Simplified Chinese text:* For: 这个论文是为了解决心理疾病诊断工具开发和研究中的数据缺乏问题，特别是来自发展中和发展国家的人口。* Methods: 论文提供了一个来自西非奈比亚裔人群的国际10/20系EEG记录集，包括休息状态、心理算数任务执行和静音刺激反应的记录。该集包括36名病例和21名健康控制者，通过美国国际精神疾病评估工具（MINI）和精神病Symptoms Scale（PANSS）和世界卫生组织残疾评估表（WHODAS）进行诊断和评估。所有病例都是医学心理病医院的门诊病人，而控制者则是从学生中报名参与研究。* Results: 这个数据集可以用于心理和计算神经科学研究人员对假设和诊断的研究。Abstract
This work has been carried out to improve the dearth of high-quality EEG datasets used for schizophrenia diagnostic tools development and studies from populations of developing and underdeveloped regions of the world. To this aim, the presented dataset contains international 10/20 system EEG recordings from West African subjects of Nigerian origin under rest conditions, in restful states, mental arithmetic task execution states and while passively reacting to auditory stimuli. The subjects are divided into cases and healthy controls and recorded from 36 cases and 21 healthy conTrol subjects identified by the Mini International Schizophrenia Interview (MINI) and also assessed by the Positive and Negative Symptoms Scale (PANSS) and the World Health Organization Disability Assessment Schedule (WHODAS). All cases are admitted schizophrenia patients of the Mental Health Ward, Medical Outpatient Department of the Obafemi Awolowo University Teaching Hospital Complex (OAUTHC, Ile-Ife) and its subsidiary Wesley Guild Hospital Unit (OAUTHC, Ilesa). Controls are drawn from students who volunteered to participate in the study at the Mental Health Ward of OAUTHC and the Wesley Guild Hospital Unit. The recordings are available at Datasets. This dataset can be used by the neuroscience and computational psychiatry research community studying the diagnosis and prognosis of schizophrenia using the electroencephalogram signal modality.
摘要
这些工作是为了改善听力和发展地区的学者和国际10/20系统EEG记录用于诊断和研究听力和发展地区的患有精神病的工具和研究。为此，所提供的数据集包括西非nigérian起源的 sujet的国际10/20系统EEG记录，包括休息状态下、数学计算任务执行状态和听力刺激反应状态。参与者分为患者和健康控制群，共有36名患者和21名健康控制者，经过MINI对话和PANSS和WHODAS评估。所有患者都是听力和发展地区医院诊断的精神病患者， controls来自医院志愿者和学生。这些记录可供 neuroscience和计算心理学研究人员使用，以研究诊断和评估听力和发展地区患有精神病的电энцефалограм信号模式。
Computing an Entire Solution Path of a Nonconvexly Regularized Convex Sparse Model
methods: 本文使用了一种名为 least angle regression（LARS）算法，用于解决 GMC 模型中的非 convex 稀疏正则化问题。
results: 本文提出了一种基于 LARS 算法的解决方法，可以在一定条件下确定 GMC 模型的解决方案，并且证明了该方法的正确性和终止性。Abstract
The generalized minimax concave (GMC) penalty is a nonconvex sparse regularizer which can preserve the overall-convexity of the sparse least squares problem. In this paper, we study the solution path of a special but important instance of the GMC model termed the scaled GMC (sGMC) model. We show that despite the nonconvexity of the regularizer, there exists a solution path of the sGMC model which is piecewise linear as a function of the tuning parameter, and we propose an efficient algorithm for computing a solution path of this type. Our algorithm is an extension of the well-known least angle regression (LARS) algorithm for LASSO, hence we term the proposed algorithm LARS-sGMC. Under suitable conditions, we provide a proof of the correctness and finite termination of the proposed LARS-sGMC algorithm. This article also serves as an appendix for the short paper titled ``COMPUTING AN ENTIRE SOLUTION PATH OF A NONCONVEXLY REGULARIZED CONVEX SPARSE MODEL", and addresses proofs and technical derivations that were omitted in the original paper due to space limitation.
摘要
“通用最小最大（GMC） penalty 是一种非 convex 精炼的减法，可以保持精炼最小二乘问题的总性 convexity。在这篇论文中，我们研究了一个特殊 yet 重要的 GMC 模型实例，称为缩放 GMC（sGMC）模型。我们证明了，尽管减法非 convex，但是存在一个具有 piecewise 线性函数形式的解路参数，并提出了一种高效的算法来计算这种类型的解路。我们的算法是 LARS 算法的扩展，因此我们称之为 LARS-sGMC。在适用条件下，我们提供了一证明该算法的正确性和终止性。这篇文章同时也是对短篇论文《计算一个非 convex 精炼的减法梯度方程》的补充，并 Addresses 证明和技术 derivations ，因为空间限制而被 omitted 在原始论文中。”Note: Simplified Chinese is a written form of Chinese that uses simpler grammar and vocabulary than Traditional Chinese. It is commonly used in mainland China and Singapore.
Beamforming Design for Active RIS-Aided Over-the-Air Computation
results: 对两种特定的情况进行分析，显示了活动RIS在MSE方面的超越性，并且对自防干扰的情况进行了适应。为处理resultant Highly non-convex问题，我们还提出了一种two-layer AO框架。实验结果表明，活动RIS可以备受提高空中计算性能。Abstract
Over-the-air computation (AirComp) is emerging as a promising technology for wireless data aggregation. However, its performance is hampered by users with poor channel conditions. To mitigate such a performance bottleneck, this paper introduces an active reconfigurable intelligence surface (RIS) into the AirComp system. Specifically, we begin by exploring the ideal RIS model and propose a joint optimization of the transceiver design and RIS configuration to minimize the mean squared error (MSE) between the target and estimated function values. To manage the resultant tri-convex optimization problem, we employ the alternating optimization (AO) technique to decompose it into three convex subproblems, each solvable optimally. Subsequently, we investigate two specific cases and analyze their respective asymptotic performance to reveal the superiority of the active RIS in mitigating the MSE relative to its passive counterpart. Lastly, we adapt our transceiver and RIS configuration design to account for the self-interference of the active RIS. To handle the resultant highly non-convex problem, we further devise a two-layer AO framework. Simulation results demonstrate the superiority of the active RIS in enhancing AirComp performance compared to its passive counterpart.
摘要
随空计算（AirComp）技术在无线数据集成中出现为一种有前途的技术。然而，其性能受用户的通道条件的影响，这会导致性能瓶颈。为了解决这个性能瓶颈，本文在AirComp系统中引入活动可配置表面（RIS）。 Specifically，我们开始是exploring the ideal RIS model，并提出了joint optimization of the transceiver design and RIS configuration，以最小化目标和估算函数值的均方差（MSE）。 To handle the resultant tri-convex optimization problem, we employ the alternating optimization（AO）technique to decompose it into three convex subproblems，each solvable optimally。后续，我们investigate two specific cases and analyze their respective asymptotic performance，以透视活动RIS在MSE方面的superiority compared to its passive counterpart。 Lastly, we adapt our transceiver and RIS configuration design to account for the self-interference of the active RIS。 To handle the resultant highly non-convex problem，we further devise a two-layer AO framework。 Simulation results demonstrate the superiority of the active RIS in enhancing AirComp performance compared to its passive counterpart。
URLLC-Awared Resource Allocation for Heterogeneous Vehicular Edge Computing
results: 实验结果显示，提出的资源分配策略能够有效地减少系统利用率，同时满足URLLC需求。Abstract
Vehicular edge computing (VEC) is a promising technology to support real-time vehicular applications, where vehicles offload intensive computation tasks to the nearby VEC server for processing. However, the traditional VEC that relies on single communication technology cannot well meet the communication requirement for task offloading, thus the heterogeneous VEC integrating the advantages of dedicated short-range communications (DSRC), millimeter-wave (mmWave) and cellular-based vehicle to infrastructure (C-V2I) is introduced to enhance the communication capacity. The communication resource allocation and computation resource allocation may significantly impact on the ultra-reliable low-latency communication (URLLC) performance and the VEC system utility, in this case, how to do the resource allocations is becoming necessary. In this paper, we consider a heterogeneous VEC with multiple communication technologies and various types of tasks, and propose an effective resource allocation policy to minimize the system utility while satisfying the URLLC requirement. We first formulate an optimization problem to minimize the system utility under the URLLC constraint which modeled by the moment generating function (MGF)-based stochastic network calculus (SNC), then we present a Lyapunov-guided deep reinforcement learning (DRL) method to convert and solve the optimization problem. Extensive simulation experiments illustrate that the proposed resource allocation approach is effective.
摘要
methods: 使用EXTREMELY LARGE ANTENNA ARRAYS (ELAAs)和多个垂直偏振 polarization
results: 在near-field中，可以达到3个空间幂数度的提高系统性能，但在far-field中只能达到2个空间幂数度。提供了一种近似式来计算可能的速率，并 derive了最佳天线间距和数组大小的近似值。Abstract
One of the most relevant challenges in future 6G wireless networks is how to support a massive spatial multiplexing of a large number of user terminals. Recently, extremely large antenna arrays (ELAAs), also referred to as extra-large MIMO (XL-MIMO), have emerged as an potential enabler of this type of spatially multiplexed transmission. These massive configurations substantially increase the number of available spatial degrees of freedom (transmission modes) while also enabling to spatially focus the transmitted energy into a very small region, thanks to the properties of near-field propagation and the large number of transmitters. This work explores whether multiplexing of multiple orthogonal polarizations can enhance the system performance in the near-field. We concentrate on a simple scenario consisting of a Uniform Linear Array (ULA) and a single antenna element user equipment (UE). We demonstrate that the number of spatial degrees of freedom can be as large as 3 in the near-field of a Line of Sight (LoS) channel when both transmitter and receiver employ three orthogonal linear polarizations. In the far-field, however, the maximum number of spatial degrees of freedom tends to be only 2, due to the fact that the equivalent MIMO channel becomes rank deficient. We provide an analytical approximation to the achievable rate, which allows us to derive approximations to the optimal antenna spacing and array size that maximize the achievable rate
摘要
一个未来6G无线网络中最重要的挑战是如何支持大量的空间多播，以提高用户终端的数量。最近，非常大的天线阵列（ELAA）或称为超大多个MIMO（XL-MIMO），已经被视为可能的激活器。这些庞大的配置可以增加可用的空间度量的数量，同时也可以将发射的能量在非常小的区域中集中，因为近场传播的特性和大量的发射器。这项工作探讨了 whether 多个归一化的极化可以提高系统性能在近场。我们专注于一个简单的enario，包括一个 uniform linear array (ULA) 和一个单antenna元素用户设备 (UE)。我们示出，在Line of Sight (LoS) 通道的近场中，当发射器和接收器都使用三个垂直的直角极化时，可以达到3个空间度量的最大数量。在远场中，然而，最大的空间度量通常只有2个，因为等效的MIMO通道变得缺少级别。我们提供了一个分析近似的可 achievable 率，允许我们 derive 最佳天线间距和阵列大小，以便最大化可 achievable 率。
Feasibility Analysis of In-Band Coexistence in Dense LEO Satellite Communication Systems
results: 我们发现，无论哪些Starlink和Kuiper卫星被用来服务用户，都会出现非常高和非常低的干扰情况。然而，我们显示Kuiper可以通过精心选择其卫星来保护Starlink地面用户，并同时为自己的地面用户提供近 maximun的下降SINR。这表明了两个稀密的LEO卫星系统之间的共存可能性，即使一个系统具有限制了知ledge of 另一个系统的服务卫星。Abstract
This work provides a rigorous methodology for assessing the feasibility of spectrum sharing between large low-earth orbit (LEO) satellite constellations. For concreteness, we focus on the existing Starlink system and the soon-to-be-launched Kuiper system, which is prohibited from inflicting excessive interference onto the incumbent Starlink ground users. We carefully model and study the potential downlink interference between the two systems and investigate how strategic satellite selection may be used by Kuiper to serve its ground users while also protecting Starlink ground users. We then extend this notion of satellite selection to the case where Kuiper has limited knowledge of Starlink's serving satellite. Our findings reveal that there is always the potential for very high and extremely low interference, depending on which Starlink and Kuiper satellites are being used to serve their users. Consequently, we show that Kuiper can protect Starlink ground users with high probability, by strategically selecting which of its satellites are used to serve its ground users. Simultaneously, Kuiper is capable of delivering near-maximal downlink SINR to its own ground users. This highlights a feasible route to the coexistence of two dense LEO satellite systems, even in scenarios where one system has limited knowledge of the other's serving satellites.
摘要
Multi-Rate Variable-Length CSI Compression for FDD Massive MIMO
paper_authors: Bumsu Park, Heedong Do, Namyoon Lee
for: 提高 Frequency-division-duplexing (FDD) 系统中 Channel State Information (CSI) 反馈过程中的效率，适用于多antenna 系统。
methods: 使用 Variational Autoencoder (VAE) WITH entropy bottleneck structure，实现多速率和变长操作的可变CSI压缩方法。
results: 比较研究表明，提出的方法能够在normalized mean squared error 方面与现有的CSI压缩技术相比，表现更高效。Abstract
For frequency-division-duplexing (FDD) systems, channel state information (CSI) should be fed back from the user terminal to the base station. This feedback overhead becomes problematic as the number of antennas grows. To alleviate this issue, we propose a flexible CSI compression method using variational autoencoder (VAE) with an entropy bottleneck structure, which can support multi-rate and variable-length operation. Numerical study confirms that the proposed method outperforms the existing CSI compression techniques in terms of normalized mean squared error.
摘要
(Simplified Chinese translation)For FDD系统，用户终端需要将通道状态信息（CSI）反馈给基站。这种反馈 overhead 随antenna数量增加而变得问题。为解决这个问题，我们提议使用变量自动编码器（VAE）与Entropy瓶颈结构，可以支持多速和变长操作。数学研究表明，我们的方法在Normalized Mean Squared Error（NMSE）上比既有CSI压缩技术更高。
results: 通过使用 alternate optimization 方法和提档分配方法，实现了 mmWave 高速列车网络中throughput的提高，并且可以考虑基站扫描、IRS离散阶跃和传输功率的约束。Abstract
With the increasing demands from passengers for data-intensive services, millimeter-wave (mmWave) communication is considered as an effective technique to release the transmission pressure on high speed train (HST) networks. However, mmWave signals ncounter severe losses when passing through the carriage, which decreases the quality of services on board. In this paper, we investigate an intelligent refracting surface (IRS)-assisted HST communication system. Herein, an IRS is deployed on the train window to dynamically reconfigure the propagation environment, and a hybrid time division multiple access-nonorthogonal multiple access scheme is leveraged for interference mitigation. We aim to maximize the overall throughput while taking into account the constraints imposed by base station beamforming, IRS discrete phase shifts and transmit power. To obtain a practical solution, we employ an alternating optimization method and propose a two-stage algorithm. In the first stage, the successive convex approximation method and branch and bound algorithm are leveraged for IRS phase shift design. In the second stage, the Lagrangian multiplier method is utilized for power allocation. Simulation results demonstrate the benefits of IRS adoption and power allocation for throughput improvement in mmWave HST networks.
摘要
随着乘客对数据密集服务的需求不断增长， millimeter wave（mmWave）通信被视为一种有效的技术来减轻高速列车网络的传输压力。然而，mmWave信号在车厢内遇到严重的吸收损耗，从而降低了列车上的服务质量。在这篇论文中，我们调查了一个智能折射表面（IRS）协助高速列车通信系统。在这种系统中，我们在列车窗户上部署了一个IRS，以动态重新配置媒体传播环境。此外，我们采用了一种混合时分多址-非对称多址方案来缓解干扰。我们的目标是最大化总 Throughput，同时考虑基站扫描、IRS阶段扫描和发射功率的约束。为了获得实用的解决方案，我们采用了一种 alternate optimization 方法，并提出了一个两stage算法。在第一阶段，我们利用了Successive Convex Approximation 方法和分支约束算法来设计IRS阶段扫描。在第二阶段，我们利用了Lagrangian multiplier方法来进行功率分配。 simulation results 表明，采用IRS和功率分配可以提高 mmWave 高速列车网络的 Throughput。