eess.SP - 2023-10-04

Index-Modulated Metasurface Transceiver Design using Reconfigurable Intelligent Surfaces for 6G Wireless Networks

  • paper_url: http://arxiv.org/abs/2310.03208
  • repo_url: None
  • paper_authors: JohnA. Hodge, Kumar Vijay Mishra, Brian M. Sadler, Amir I. Zaghloul
  • for: 本研究旨在提高 sixth-generation 无线网络的数据速率和能效性,并提出了一种新的扩展技术——指标修改(Index Modulation,IM)。
  • methods: 本研究使用了智能表面(Reconfigurable Intelligent Surface,RIS)的电磁特性来实现 IM,包括指向调制、空间多普通模式和相位调制能力。
  • results: 数值实验表明,通过 RIS 协助 IM 实现可以获得较佳的比错率表现,而且可以通过调整反射相位来实现 IM 的程序化。
    Abstract Higher spectral and energy efficiencies are the envisioned defining characteristics of high data-rate sixth-generation (6G) wireless networks. One of the enabling technologies to meet these requirements is index modulation (IM), which transmits information through permutations of indices of spatial, frequency, or temporal media. In this paper, we propose novel electromagnetics-compliant designs of reconfigurable intelligent surface (RIS) apertures for realizing IM in 6G transceivers. We consider RIS modeling and implementation of spatial and subcarrier IMs, including beam steering, spatial multiplexing, and phase modulation capabilities. Numerical experiments for our proposed implementations show that the bit error rates obtained via RIS-aided IM outperform traditional implementations. We further establish the programmability of these transceivers to vary the reflection phase and generate frequency harmonics for IM through full-wave electromagnetic analyses of a specific reflect-array metasurface implementation.
    摘要 高 spectral 和能量效率是 sixth-generation (6G) 无线网络的定义特征。一种实现这些要求的技术是指标模ulation (IM), 它通过媒体的 indeces permutation 传输信息。在这篇论文中,我们提议了新的 electromagnetics-compliant 设计,用于实现 IM 在 6G 接收机中。我们考虑了 RIS 模型和实现,包括杆导向、空载多普通量和相位修正能力。我们的numerical experiment 表明,通过 RIS 帮助 IM,可以获得较低的错误率。我们还证明了这些接收机的可编程性,可以通过调整反射相位和生成频率幂来实现 IM。Here's a word-for-word translation of the text using Traditional Chinese characters:高 spectral 和能量效率是 sixth-generation (6G) 无线网络的定义特征。一种实现这些要求的技术是指标模ulation (IM), 它通过媒体的 indeces permutation 传送信息。在这篇论文中,我们提议了新的 electromagnetics-compliant 设计,用于实现 IM 在 6G 接收机中。我们考虑了 RIS 模型和实现,包括杆导向、空载多普通量和相位修正能力。我们的numerical experiment 表明,通过 RIS 帮助 IM,可以获得较低的错误率。我们也证明了这些接收机的可编程性,可以通过调整反射相位和生成频率幂来实现 IM。

Impedance Leakage Vulnerability and its Utilization in Reverse-engineering Embedded Software

  • paper_url: http://arxiv.org/abs/2310.03175
  • repo_url: None
  • paper_authors: Md Sadik Awal, Md Tauhidur Rahman
  • for: 保护系统和数据免受物理攻击,发现新的漏洞和实施安全和隐私措施是非常重要。
  • methods: 本文探讨了一种受到忽略或者狭隘研究的漏洞——阻抗性,它可以通过非典型的侧途泄露信息,对系统和数据安全和隐私带来潜在的威胁。
  • results: 本文表明了ATmega328P微控制器和Artix 7 FPGA的阻抗性不是固定的,而是与运行在这些设备上的软件有直接关系。我们称之为阻抗性泄露,并使其成为一种侧途来检测保护内存中的软件指令。我们的实验表明,阻抗性侧途可以准确地检测软件指令,具体数据如下:ATmega328P微控制器的准确率为96.1%,Artix 7 FPGA的准确率为92.6%。此外,我们还探讨了阻抗性侧途的双重性,包括可能的利用和知识产权盗用的风险。最后,我们提出了特定地址 impedance leakage的防范措施。
    Abstract Discovering new vulnerabilities and implementing security and privacy measures are important to protect systems and data against physical attacks. One such vulnerability is impedance, an inherent property of a device that can be exploited to leak information through an unintended side channel, thereby posing significant security and privacy risks. Unlike traditional vulnerabilities, impedance is often overlooked or narrowly explored, as it is typically treated as a fixed value at a specific frequency in research and design endeavors. Moreover, impedance has never been explored as a source of information leakage. This paper demonstrates that the impedance of an embedded device is not constant and directly relates to the programs executed on the device. We define this phenomenon as impedance leakage and use this as a side channel to extract software instructions from protected memory. Our experiment on the ATmega328P microcontroller and the Artix 7 FPGA indicates that the impedance side channel can detect software instructions with 96.1% and 92.6% accuracy, respectively. Furthermore, we explore the dual nature of the impedance side channel, highlighting the potential for beneficial purposes and the associated risk of intellectual property theft. Finally, potential countermeasures that specifically address impedance leakage are discussed.
    摘要 发现新的漏洞和实施安全和隐私措施是保护系统和数据 против物理攻击的重要方法。一种这样的漏洞是阻力,它是设备的自然属性,可以通过不当的副通道泄露信息,从而带来严重的安全和隐私风险。与传统的漏洞不同,阻力通常被忽略或者狭采,因为它通常被视为一个固定的值,在研究和设计中。此外,阻力从未被探讨作为信息泄露的来源。这篇论文表明,阻力不是固定的,而是与在设备上执行的程序直接相关。我们称这种现象为阻力泄露,并使其作为副通道来提取保护内存中的软件指令。我们的实验表明,阻力副通道可以准确地检测软件指令,具体来说,在ATmega328P微控制器和Artix 7 FPGA上,阻力副通道可以检测软件指令的准确率分别为96.1%和92.6%。此外,我们还探讨了阻力副通道的双重性,并指出了这种副通道的潜在利用和知识产权盗用的风险。最后,我们提出了专门针对阻力泄露的防范措施。

Dynamic Changes of Brain Network during Epileptic Seizure

  • paper_url: http://arxiv.org/abs/2310.03151
  • repo_url: None
  • paper_authors: Atefeh Khoshkhahtinat, Hoda Mohammadzade
  • For: 这个研究旨在探索 epilepsy 患者的脑网络在癫痫期间的动态变化,以便提高诊断和治疗的效果。* Methods: 这个研究使用了频率带的phas lag index (PLI) 测量,并使用图论学技术提取脑网络的 topological 特征。 然后,一种无supervised clustering方法用于检查脑网络在癫痫期间的状态转移。* Results: 研究发现,癫痫期间脑的同步水平高于预癫痫和后癫痫期间的theta、alpha 和 beta 频率带,而gamma 频率带的同步水平下降。这些变化还导致脑网络的topological 特征在癫痫期间发生变化。此外,研究发现脑网络在癫痫期间的动态变化比传统的三个状态模型(预癫痫、癫痫、后癫痫)复杂得多,脑网络在癫痫期间的变化缓慢于预癫痫和后癫痫期间。
    Abstract Epilepsy is a neurological disorder identified by sudden and recurrent seizures, which are believed to be accompanied by distinct changes in brain dynamics. Exploring the dynamic changes of brain network states during seizures can pave the way for improving the diagnosis and treatment of patients with epilepsy. In this paper, the connectivity brain network is constructed using the phase lag index (PLI) measurement within five frequency bands, and graph-theoretic techniques are employed to extract topological features from the brain network. Subsequently, an unsupervised clustering approach is used to examine the state transitions of the brain network during seizures. Our findings demonstrate that the level of brain synchrony during the seizure period is higher than the pre-seizure and post-seizure periods in the theta, alpha, and beta bands, while it decreases in the gamma bands. These changes in synchronization also lead to alterations in the topological features of functional brain networks during seizures. Additionally, our results suggest that the dynamics of the brain during seizures are more complex than the traditional three-state model (pre-seizure, seizure, and post-seizure) and the brain network state exhibits a slower rate of change during the seizure period compared to the pre-seizure and post-seizure periods.
    摘要 EPilepsy 是一种神经疾病,标志于不断发生的发作,这些发作通常附有脑动力学的变化。研究发作期间脑网络的动态变化可能为患EPilepsy 患者的诊断和治疗带来新的想法。在这篇论文中,我们使用相位延迟指数(PLI)测量在五个频率带中的脑网络连接度,并使用图论技术提取脑网络的 topological 特征。然后,我们使用无supervised clustering 方法检查脑网络在发作期间的状态转移。我们发现在发作期间,脑的同步水平高于预发作和后发作期间的theta、alpha和beta频率带,而在gamma频率带下降。这些变化也导致了脑网络的 topological 特征的变化。此外,我们的结果表明,脑在发作期间的动态不仅比传统的三个状态模型(预发作、发作、后发作)复杂,而且发作期间脑网络的变化速率也比预发作和后发作期间 slower。

Dual mode multispectral imaging system for food and agricultural product quality estimation

  • paper_url: http://arxiv.org/abs/2310.03110
  • repo_url: None
  • paper_authors: Darsha Udayanga, Ashan Serasinghe, Supun Dassanayake, Roshan Godaliyadda, H. M. V. R. Herath, M. P. B. Ekanayake, H. L. P. Malshan
  • for: 这个论文的目的是提出一种基于多spectral成像技术和人工智能机器学习技术的食品质量控制方法,以代替传统的实验室测试方法。
  • methods: 这个论文使用了反射和传输成像技术,并应用了人工智能机器学习和处理技术来分析数据。
  • results: 论文的实验结果显示,这种方法可以准确地识别不同类型的食品,包括固体和液体样本。具体来说,在标准色彩标准样本和巧克力油涂抹样本中,该方法可以达到90%以上的准确率,而在巧克力油涂抹样本中,该方法可以达到95%以上的准确率。同时,该方法还可以提供最高的准确率(99%) для溶解液体样本。
    Abstract Multispectral imaging coupled with Artificial Intelligence, Machine Learning and Signal Processing techniques work as a feasible alternative for laboratory testing, especially in food quality control. Most of the recent related research has been focused on reflectance multispectral imaging but a system with both reflectance, transmittance capabilities would be ideal for a wide array of specimen types including solid and liquid samples. In this paper, a device which includes a dedicated reflectance mode and a dedicated transmittance mode is proposed. Dual mode operation where fast switching between two modes is facilitated. An innovative merged mode is introduced in which both reflectance and transmittance information of a specimen are combined to form a higher dimensional dataset with more features. Spatial and temporal variations of measurements are analyzed to ensure the quality of measurements. The concept is validated using a standard color palette and specific case studies are done for standard food samples such as turmeric powder and coconut oil proving the validity of proposed contributions. The classification accuracy of standard color palette testing was over 90% and the accuracy of coconut oil adulteration was over 95%. while the merged mode was able to provide the best accuracy of 99% for the turmeric adulteration. A linear functional mapping was done for coconut oil adulteration with an R2 value of 0.9558.
    摘要 多spectral成像技术与人工智能、机器学习和信号处理技术结合,成为实验室测试的可行 alternativa,特别是食品质量控制。大多数最近相关的研究都集中在反射多spectral成像上,但一个包含反射和传输功能的系统会对各种样本类型进行更广泛的应用,包括固体和液体样本。本文提出了一种设备,它包括专门的反射模式和传输模式,并且具有快速切换 между两个模式的能力。我们还提出了一种创新的合并模式,在该模式下,反射和传输样本的信息被组合成一个高维数据集,其中包含更多的特征。我们进行了空间和时间变化的分析,以确保测量的质量。我们验证了提出的贡献,使用标准颜色谱和具体的食品样本测试,如胡萝卜粉和椰子油,结果显示了我们的提出的贡献的有效性。标准颜色谱测试的准确率高于90%,椰子油饱和质量的准确率高于95%,而合并模式能够提供最高的准确率99%。我们还进行了线性函数映射,其R2值为0.9558。

SNR-Adaptive Ranging Waveform Design Based on Ziv-Zakai Bound Optimization

  • paper_url: http://arxiv.org/abs/2310.02963
  • repo_url: None
  • paper_authors: Yifeng Xiong, Fan Liu
  • for: 本研究旨在提高无线应用中的定位精度,通过高精度测距来实现高精度定位。
  • methods: 本文提出了基于Ziv-Zakai bound(ZZB)的测距波形设计算法,该算法具有在给定SNR下实现最佳ZZB的理论保证。
  • results: numericalresults表明,在低SNR режимом,探测信号的检测概率成为测距信号的主要确定因素,而不是解析精度。
    Abstract Location-awareness is essential in various wireless applications. The capability of performing precise ranging is substantial in achieving high-accuracy localization. Due to the notorious ambiguity phenomenon, optimal ranging waveforms should be adaptive to the signal-to-noise ratio (SNR). In this letter, we propose to use the Ziv-Zakai bound (ZZB) as the ranging performance metric, as well as an associated waveform design algorithm having theoretical guarantee of achieving the optimal ZZB at a given SNR. Numerical results suggest that, in stark contrast to the well-known high-SNR design philosophy, the detection probability of the ranging signal becomes more important than the resolution in the low-SNR regime.
    摘要 Location-awareness 是各种无线应用中的关键因素。精准范围测量的能力是实现高精度定位的关键。由于著名的歧义现象,最佳的范围波形应对 Signal-to-Noise Ratio(SNR)进行适应。在这封信中,我们提议使用 Ziv-Zakai bound(ZZB)作为范围性能指标,以及与之相应的波形设计算法,具有理论保证可以在给定的 SNR 下实现最佳 ZZB。数字结果表明,在低 SNR Régime 中,探测范围信号的检测概率变得更加重要于分辨率。

Dark Side of HAPS Systems: Jamming Threats towards Satellites

  • paper_url: http://arxiv.org/abs/2310.02851
  • repo_url: None
  • paper_authors: Hadil Otay, Khaled Humadi, Gunes Karabulut Kurt
  • For: 本研究旨在为6G时代的卫星通信网络提供安全保障,特别是在低地球轨道卫星网络中提高卫星与地面站之间的通信可靠性。* Methods: 本研究采用了两种LEO卫星通信场景,分别是一个发送卫星、一个接收地面站和一个高空平台站(HAPS)的干扰攻击场景,以及两个卫星、一个发送卫星和一个接收地面站的干扰攻击场景。* Results: 我们通过发展数学模型,研究干扰信号对系统的影响,并发现在第二个场景中,卫星协作可以提高系统的安全性,因为干扰效果只会在两个链路同时受到攻击时发生极端情况。
    Abstract Securing satellite communication networks is imperative in the rapidly evolving landscape of advanced telecommunications, particularly in the context of 6G advancements. This paper establishes a secure low earth orbit (LEO) satellite network paradigm to address the challenges of the evolving 6G era, with a focus on enhancing communication integrity between satellites and ground stations. Countering the threat of jamming, which can disrupt vital communication channels, is a key goal of this work. In particular, this paper investigates the performance of two LEO satellite communication scenarios under the presence of jamming attacker. In the first scenario, we consider a system that comprises one transmitting satellite, a receiving ground station, and a high altitude platform station (HAPS) acting as a jammer. The HAPS disrupts communication between the satellite and the ground station, impeding signal transmission. The second scenario involves two satellites, one is the transmitter while the other works as a relay, accompanied by a ground station, and a jamming HAPS. In this scenario, the transmitting satellite sends data to the ground station using two different paths, i.e., direct and indirect transmission paths, with a relay satellite acting as an intermediary in the case of indirect transmission. For both scenarios, we study the system security by developing mathematical frameworks to investigate the outage effect resulting from the jamming signals orchestrated by the HAPS. Our results show that the satellite cooperation in the second scenario improves the system's security since the extreme jamming effect occurs only when both links are simultaneously disturbed.
    摘要 保护卫星通信网络是在高速发展的电信技术领域中非常重要的,特别是在6G技术的发展背景下。本文提出了一种安全的低地球轨(LEO)卫星网络模式,以解决6G时代的演进中的通信完整性问题。对于干扰攻击的威胁来说,这种工作是非常重要的。本文研究了两种LEO卫星通信场景下,干扰攻击的影响。在第一个场景中,我们考虑了一个包括一个发送卫星、一个接收地面站和一个高空平台站(HAPS)的系统。HAPS会中断卫星和地面站之间的通信,从而阻挡信号传输。在第二个场景中,我们有两个卫星,其中一个是发送器,另一个是 relay,以及一个地面站,以及一个干扰HAPS。在这个场景中,发送卫星将数据传输到地面站使用两种不同的路径,即直接传输和间接传输, relay卫星在 indirect transmission 的情况下 acts as an intermediary。为了两个场景,我们研究了系统的安全性,并开发了数学模型来研究干扰信号所引起的系统停机的影响。我们的结果表明,在第二个场景中,卫星合作可以提高系统的安全性,因为干扰效果只会在两个链路同时受到影响时发生极端情况。

Graph-based Simultaneous Localization and Bias Tracking

  • paper_url: http://arxiv.org/abs/2310.02814
  • repo_url: None
  • paper_authors: Alexander Venus, Erik Leitinger, Stefan Tertinek, Florian Meyer, Klaus Witrisal
  • for: 本研究旨在提供一种robust的移动设备位置测定和跟踪方法,可以在多Path环境中提供高精度的位置估计。
  • methods: 本研究使用因子图形式和粒子基于加法产品算法,并且提出了一种序列算法,可以同时估计移动设备的位置和时变多Path组件(MPCs)的延迟偏好。
  • results: 本研究表明,使用 simulate和实际测量数据,提出的算法可以在多Path环境中提供高精度的位置估计,并且常常达到 posterior Cramer-Rao下限(P-CRLB)。此外,研究还发现该方法可以自动标识不可靠测量,从而避免lost track。
    Abstract We present a factor graph formulation and particle-based sum-product algorithm for robust localization and tracking in multipath-prone environments. The proposed sequential algorithm jointly estimates the mobile agent's position together with a time-varying number of multipath components (MPCs). The MPCs are represented by "delay biases" corresponding to the offset between line-of-sight (LOS) component delay and the respective delays of all detectable MPCs. The delay biases of the MPCs capture the geometric features of the propagation environment with respect to the mobile agent. Therefore, they can provide position-related information contained in the MPCs without explicitly building a map of the environment. We demonstrate that the position-related information enables the algorithm to provide high-accuracy position estimates even in fully obstructed line-of-sight (OLOS) situations. Using simulated and real measurements in different scenarios we demonstrate the proposed algorithm to significantly outperform state-of-the-art multipath-aided tracking algorithms and show that the performance of our algorithm constantly attains the posterior Cramer-Rao lower bound (P-CRLB). Furthermore, we demonstrate the implicit capability of the proposed method to identify unreliable measurements and, thus, to mitigate lost tracks.
    摘要 我们提出了一种因子图表示法和粒子基于汇聚积分算法,用于robust的位置Localization和跟踪在多path环境中。我们的顺序算法同时估算移动代理的位置和时变多path组件(MPCs)的数量。MPCs被表示为“延迟偏好”,这些偏好对应于从视线组件延迟到所有检测到的MPCs的延迟。延迟偏好 capture了在移动代理周围的媒体传播环境的几何特征,因此它们可以提供位置相关的信息,无需显式建立环境地图。我们示出了我们的算法可以在完全遮挡视线(OLOS)情况下提供高精度的位置估计。使用模拟和实际测量数据,我们示出了我们的算法在不同enario中显著超越了当前的多path护航算法,并且示出了我们的算法的性能一直达到 posterior Cramer-Rao下限(P-CRLB)。此外,我们还示出了我们的方法可以识别不可靠的测量,从而 mitigate lost tracks。

Beyond Diagonal Reconfigurable Intelligent Surfaces with Mutual Coupling: Modeling and Optimization

  • paper_url: http://arxiv.org/abs/2310.02708
  • repo_url: None
  • paper_authors: Hongyu Li, Shanpu Shen, Matteo Nerini, Marco Di Renzo, Bruno Clerckx
  • for: 本文研究了卷积式智能表面(BD-RIS)干支持无线通信系统中的相互干扰问题。
  • methods: 作者首先 derivates the mutual coupling aware BD-RIS aided communication model using scattering and impedance parameter analysis。然后,他们提出了一种通用的BD-RIS优化算法,可以应用于不同的BD-RIS架构,以最大化通道增强。
  • results: 数值结果表明了提案的设计的有效性,并示出了相对于正常对角RIS的增强效果随着相互干扰的增加。
    Abstract This work studies the modeling and optimization of beyond diagonal reconfigurable intelligent surface (BD-RIS) aided wireless communication systems in the presence of mutual coupling among the RIS elements. Specifically, we first derive the mutual coupling aware BD-RIS aided communication model using scattering and impedance parameter analysis. Based on the obtained communication model, we propose a general BD-RIS optimization algorithm applicable to different architectures of BD-RIS to maximize the channel gain. Numerical results validate the effectiveness of the proposed design and demonstrate that the larger the mutual coupling the larger the gain offered by BD-RIS over conventional diagonal RIS.
    摘要

Spectral vs Energy Efficiency in 6G: Impact of the Receiver Front-End

  • paper_url: http://arxiv.org/abs/2310.02622
  • repo_url: None
  • paper_authors: Angel Lozano, Sundeep Rangan
  • for: 本研究探讨了收发前端(RFE)在无线设备中的作用,以及如何通过信息理论来优化RFE的功率消耗。
  • methods: 本研究使用了新的模型和假设,以描述RFE在不同频率、宽扩比和antenna数下的行为。
  • results: 研究发现,随着频率、宽扩比和antenna数的提高,RFE的功率消耗会随之增加,这会导致更多的噪声、非线性和粗糙量化。这种负面效应需要在信息理论中考虑设备功率消耗,以提高6G系统的能效性。
    Abstract This article puts the spotlight on the receiver front-end (RFE), an integral part of any wireless device that information theory typically idealizes into a mere addition of noise. While this idealization was sound in the past, as operating frequencies, bandwidths, and antenna counts rise, a soaring amount of power is required for the RFE to behave accordingly. Containing this surge in power expenditure exposes a harsher behavior on the part of the RFE (more noise, nonlinearities, and coarse quantization), setting up a tradeoff between the spectral efficiency under such nonidealities and the efficiency in the use of energy by the RFE. With the urge for radically better power consumptions and energy efficiencies in 6G, this emerges as an issue on which information theory can cast light at a fundamental level. More broadly, this article advocates the interest of having information theory embrace the device power consumption in its analyses. In turn, this calls for new models and abstractions such as the ones herein put together for the RFE, and for a more holistic perspective.
    摘要

Performance Analysis and Optimization of Reconfigurable Multi-Functional Surface Assisted Wireless Communications

  • paper_url: http://arxiv.org/abs/2310.02564
  • repo_url: None
  • paper_authors: Wen Wang, Wanli Ni, Hui Tian, Naofal Al-Dhahir
  • for: 提高无线网络性能,并且解决现有的双倍干扰和电池依赖问题。
  • methods: 提出一种新的多功能反射器(MF-RIS)架构,可以支持多种功能,包括信号反射、增强和能量收集。
  • results: 通过理论分析,得出了MF-RIS协助通信网络的可达性。与现有的自主维持RIS相比,我们计算出了MF-RIS所需的反射元素数量。在多用户无线网络中,通过joint beamforming和MF-RIS偏置的优化,提高了吞吐量。在实际场景中,我们提出了一种Robust beamforming scheme来适应不可避免的频率估计错误。最后,我们通过数据分析发现:1)相比自主维持RIS,MF-RIS可以更好地平衡能源自维和通信性能提高;2)反射器只能在发射器或接收器附近部署,而MF-RIS应该部署在发射器更近的位置以获得更高的频率效率。
    Abstract Although reconfigurable intelligent surfaces (RISs) can improve the performance of wireless networks by smartly reconfiguring the radio environment, existing passive RISs face two key challenges, i.e., double-fading attenuation and dependence on grid/battery. To address these challenges, this paper proposes a new RIS architecture, called multi-functional RIS (MF-RIS). Different from conventional reflecting-only RIS, the proposed MF-RIS is capable of supporting multiple functions with one surface, including signal reflection, amplification, and energy harvesting. As such, our MF-RIS is able to overcome the double-fading attenuation by harvesting energy from incident signals. Through theoretical analysis, we derive the achievable capacity of an MF-RIS-aided communication network. Compared to the capacity achieved by the existing self-sustainable RIS, we derive the number of reflective elements required for MF-RIS to outperform self-sustainable RIS. To realize a self-sustainable communication system, we investigate the use of MF-RIS in improving the sum-rate of multi-user wireless networks. Specifically, we solve a non-convex optimization problem by jointly designing the transmit beamforming and MF-RIS coefficients. As an extension, we investigate a resource allocation problem in a practical scenario with imperfect channel state information. By approximating the semi-infinite constraints with the S-procedure and the general sign-definiteness, we propose a robust beamforming scheme to combat the inevitable channel estimation errors. Finally, numerical results show that: 1) compared to the self-sustainable RIS, MF-RIS can strike a better balance between energy self-sustainability and throughput improvement; and 2) unlike reflecting-only RIS which can be deployed near the transmitter or receiver, MF-RIS should be deployed closer to the transmitter for higher spectrum efficiency.
    摘要 although reconfigurable intelligent surfaces (RISs) can improve the performance of wireless networks by smartly reconfiguring the radio environment, existing passive RISs face two key challenges, i.e., double-fading attenuation and dependence on grid/battery. to address these challenges, this paper proposes a new RIS architecture, called multi-functional RIS (MF-RIS). different from conventional reflecting-only RIS, the proposed MF-RIS is capable of supporting multiple functions with one surface, including signal reflection, amplification, and energy harvesting. as such, our MF-RIS is able to overcome the double-fading attenuation by harvesting energy from incident signals. through theoretical analysis, we derive the achievable capacity of an MF-RIS-aided communication network. compared to the capacity achieved by the existing self-sustainable RIS, we derive the number of reflective elements required for MF-RIS to outperform self-sustainable RIS. to realize a self-sustainable communication system, we investigate the use of MF-RIS in improving the sum-rate of multi-user wireless networks. specifically, we solve a non-convex optimization problem by jointly designing the transmit beamforming and MF-RIS coefficients. as an extension, we investigate a resource allocation problem in a practical scenario with imperfect channel state information. by approximating the semi-infinite constraints with the S-procedure and the general sign-definiteness, we propose a robust beamforming scheme to combat the inevitable channel estimation errors. finally, numerical results show that: 1) compared to the self-sustainable RIS, MF-RIS can strike a better balance between energy self-sustainability and throughput improvement; and 2) unlike reflecting-only RIS which can be deployed near the transmitter or receiver, MF-RIS should be deployed closer to the transmitter for higher spectrum efficiency.

Multi-Functional Reconfigurable Intelligent Surface: System Modeling and Performance Optimization

  • paper_url: http://arxiv.org/abs/2310.02562
  • repo_url: None
  • paper_authors: Wen Wang, Wanli Ni, Hui Tian, Yonina C. Eldar, Rui Zhang
  • for: 这 paper 描述了一种多功能可 Configurable inteligent surface(MF-RIS)架构,而不是传统的单功能 RIS(SF-RIS),该架构可同时支持多种功能,包括反射、折射、增强和能量收集 wireless 信号。因此,MF-RIS 可以增强 RIS 信号覆盖,通过增强反射/折射后的信号的增强。
  • methods: 作者提出了 MF-RIS 信号模型,并对 MF-RIS 帮助的多用户非对称多访问网络中的总比特率进行最大化。作者通过一种有效的迭代算法,对 transmit 扬性、功率分配以及不同 MF-RIS 元素的操作模式和参数进行joint 优化。
  • results: 作者通过 Simulation 结果表明,MF-RIS 比 SF-RIS 具有显著的性能提升。此外,作者还证明了 MF-RIS 的最佳部署位置应该 closer to the transmitter,以达到更高的通信吞吐量和更多的能量收集。
    Abstract In this paper, we propose and study a multi-functional reconfigurable intelligent surface (MF-RIS) architecture. In contrast to conventional single-functional RIS (SF-RIS) that only reflects signals, the proposed MF-RIS simultaneously supports multiple functions with one surface, including reflection, refraction, amplification, and energy harvesting of wireless signals. As such, the proposed MF-RIS is capable of significantly enhancing RIS signal coverage by amplifying the signal reflected/refracted by the RIS with the energy harvested. We present the signal model of the proposed MF-RIS, and formulate an optimization problem to maximize the sum-rate of multiple users in an MF-RIS-aided non-orthogonal multiple access network. We jointly optimize the transmit beamforming, power allocations as well as the operating modes and parameters for different elements of the MF-RIS and its deployment location, via an efficient iterative algorithm. Simulation results are provided which show significant performance gains of the MF-RIS over SF-RISs with only some of its functions available. Moreover, we demonstrate that there exists a fundamental trade-off between sum-rate maximization and harvested energy maximization. In contrast to SF-RISs which can be deployed near either the transmitter or receiver, the proposed MF-RIS should be deployed closer to the transmitter for maximizing its communication throughput with more energy harvested.
    摘要 在本文中,我们提出了一种多功能可重配置智能面(MF-RIS)架构,与传统的单功能RIS(SF-RIS)不同,MF-RIS同时支持多种功能,包括反射、折射、增强和能量收集等无线信号处理。因此,MF-RIS可以备受提高RIS信号覆盖率,通过增强RIS反射/折射后的信号和收集的能量进行增强。我们提出了MF-RIS信号模型,并将多用户吞吐量最大化问题转化为一个优化问题。我们通过一种高效的迭代算法,同时优化发射扩散、功率分配以及MF-RIS元素的操作模式和部署位置。实验结果表明,MF-RIS比SF-RIS具有显著的性能提升,并且存在许多功能的负面关系。此外,我们发现,MF-RIS应该在发射器更近的位置进行部署,以确保更高的通信吞吐量和更多的能量收集。

Integrated Sensing and Communications towards Proactive Beamforming in mmWave V2I via Multi-Modal Feature Fusion (MMFF)

  • paper_url: http://arxiv.org/abs/2310.02561
  • repo_url: None
  • paper_authors: Haotian Zhang, Shijian Gao, Xiang Cheng, Liuqing Yang
  • for: 提高 vehicular communication networks 的可靠性和数据传输速率,解决传输过程中的窄扩 beam alignment 问题。
  • methods: 提出一种新的积极扫描方案,通过Multi-Modal Feature Fusion Network (MMFF-Net) 集成多种感知和通信功能,以提高扫描精度。
  • results: 对 ViWi 数据集进行验证,实现更高的扫描精度和更stable的角度预测,提高可靠性和数据传输速率,并在复杂动态情况下保证Robust 预测结果。
    Abstract The future of vehicular communication networks relies on mmWave massive multi-input-multi-output antenna arrays for intensive data transfer and massive vehicle access. However, reliable vehicle-to-infrastructure links require narrow beam alignment, which traditionally involves excessive signaling overhead. To address this issue, we propose a novel proactive beamforming scheme that integrates multi-modal sensing and communications via Multi-Modal Feature Fusion Network (MMFF-Net), which is composed of multiple neural network components with distinct functions. Unlike existing methods that rely solely on communication processing, our approach obtains comprehensive environmental features to improve beam alignment accuracy. We verify our scheme on the ViWi dataset, which we enriched with realistic vehicle drifting behavior. Our proposed MMFF-Net achieves more accurate and stable angle prediction, which in turn increases the achievable rates and reduces the communication system outage probability. Even in complex dynamic scenarios, robust prediction results can be guaranteed, demonstrating the feasibility and practicality of the proposed proactive beamforming approach.
    摘要 未来的车辆通信网络将仰赖mmWave巨量多input多output天线阵列进行激烈数据传输和大量车辆存取。然而,可靠的车辆基础设施连接需要窄焦点对alignment,传统上需要过度的讯号过剩。为解决这个问题,我们提出了一个新的积极扫描方案,通过融合多modal感知和通信via多Modal特征融合网络(MMFF-Net),这是由多个神经网络 ком成分组成,每个 ком成分都有不同的功能。与现有的方法不同,我们的方法可以从感知环境中获取丰富的环境特征,以提高扫描精度。我们在ViWi dataset上验证了我们的方法,并将dataset丰富了现实的车辆滑动行为。我们的提案的MMFF-Net可以更高精度和稳定的角度预测,这样可以增加可达率和减少通信系统失效机会。甚至在复杂的动态enario中,我们可以保证Robust的预测结果,这说明了我们的积极扫描方案的可行性和实用性。

ISAC Signal Processing Over Unlicensed Spectrum Bands

  • paper_url: http://arxiv.org/abs/2310.02555
  • repo_url: None
  • paper_authors: Haotian Liu, Zhiqing Wei, Fengyun Li, Yuewei Lin, Hanyang Qu, Huici Wu, Zhiyong Feng
  • for: 本研究旨在提出一种基于压缩学习(Compressed Sensing,CS)的高精度Integrated Sensing and Communication(ISAC)信号处理算法,以解决5G NR中的非连续频谱带中的感知问题。
  • methods: 本研究使用了5G NR中的资源块组(Resource Block Group,RBG)配置信息和通道信息矩阵,以动态和准确地获取电力估计谱。此外,我们采用了快速迭代减小阈值算法(FISTA)来解决重建问题,并使用K-fold交叉验证(KCV)来获得最佳参数。
  • results: 模拟结果表明,提出的算法在非连续频谱带中具有较低的侧lobes或甚至为零侧lobes,同时具有高的抗噪性能。与传统感知算法相比,本研究的算法具有更高的精度和更低的误差。
    Abstract As a promising key technology of 6th-Generation (6G) mobile communication systems, integrated sensing and communication (ISAC) technology aims to make full use of spectrum resources to enable the functional integration of communication and sensing. The ISAC-enabled mobile communication systems regularly operate in non-continuous spectrum bands due to crowded licensed frequency bands. However, the conventional sensing algorithms over non-continuous spectrum bands have disadvantages such as reduced peak-to-sidelobe ratio (PSR) and degraded anti-noise performance. Facing this challenge, we propose a high-precision ISAC signal processing algorithm based on compressed sensing (CS) in this paper. By integrating the resource block group (RBG) configuration information in 5th-Generation new radio (5G NR) and channel information matrices, we can dynamically and accurately obtain power estimation spectra. Moreover, we employ the fast iterative shrinkage-thresholding algorithm (FISTA) to address the reconstruction problem and utilize K-fold cross validation (KCV) to obtain optimal parameters. Simulation results show that the proposed algorithm has lower sidelobes or even zero sidelobes and high anti-noise performance compared with conventional sensing algorithms.
    摘要 As a promising key technology of 6th-Generation (6G) mobile communication systems, integrated sensing and communication (ISAC) technology aims to make full use of spectrum resources to enable the functional integration of communication and sensing. The ISAC-enabled mobile communication systems regularly operate in non-continuous spectrum bands due to crowded licensed frequency bands. However, the conventional sensing algorithms over non-continuous spectrum bands have disadvantages such as reduced peak-to-sidelobe ratio (PSR) and degraded anti-noise performance. Facing this challenge, we propose a high-precision ISAC signal processing algorithm based on compressed sensing (CS) in this paper. By integrating the resource block group (RBG) configuration information in 5th-Generation new radio (5G NR) and channel information matrices, we can dynamically and accurately obtain power estimation spectra. Moreover, we employ the fast iterative shrinkage-thresholding algorithm (FISTA) to address the reconstruction problem and utilize K-fold cross validation (KCV) to obtain optimal parameters. Simulation results show that the proposed algorithm has lower sidelobes or even zero sidelobes and high anti-noise performance compared with conventional sensing algorithms.Here's the word-for-word translation in Simplified Chinese:作为6G移动通信系统的优秀关键技术,集成感知通信(ISAC)技术目的是充分利用频谱资源,实现通信和感知的函数集成。ISAC启用的移动通信系统通常在非连续频谱带中运行,由于拥堵的licensed频谱带。但是,传统的感知算法在非连续频谱带上有缺点,如降低峰夹强度比(PSR)和降低反噪性能。面临这个挑战,我们在本文中提出了基于压缩感知(CS)的高精度ISAC信号处理算法。通过将5G NR中的资源块组(RBG)配置信息和通道信息矩阵绑定在一起,我们可以在实时和准确地获取电力估计谱。此外,我们采用了快速迭代缩放阈值算法(FISTA)解决重建问题,并使用K-fold Cross Validation(KCV)获得优化参数。实验结果表明,提议的算法在传统感知算法中具有更低的夹强或 même zero夹强,以及高反噪性能。

Convergence Analysis and Latency Minimization for Semi-Federated Learning in Massive IoT Networks

  • paper_url: http://arxiv.org/abs/2310.02550
  • repo_url: None
  • paper_authors: Jianyang Ren, Wanli Ni, Hui Tian, Gaofeng Nie
  • For: This paper is written to address the issue of Federated Learning (FL) latency in Internet of Things (IoT) networks with massive devices.* Methods: The paper proposes a Semi-Federated Learning (SemiFL) paradigm that combines network pruning and over-the-air computation to reduce FL latency.* Results: The paper derives an upper bound on the convergence performance of the proposed SemiFL and formulates a convergence-constrained SemiFL latency minimization problem. Iterative algorithms are designed to solve the problem efficiently, and numerical simulations verify the effectiveness of the proposed scheme in reducing latency while maintaining identification accuracy.
    Abstract As the number of sensors becomes massive in Internet of Things (IoT) networks, the amount of data is humongous. To process data in real-time while protecting user privacy, federated learning (FL) has been regarded as an enabling technique to push edge intelligence into IoT networks with massive devices. However, FL latency increases dramatically due to the increase of the number of parameters in deep neural network and the limited computation and communication capabilities of IoT devices. To address this issue, we propose a semi-federated learning (SemiFL) paradigm in which network pruning and over-the-air computation are efficiently applied. To be specific, each small base station collects the raw data from its served sensors and trains its local pruned model. After that, the global aggregation of local gradients is achieved through over-the-air computation. We first analyze the performance of the proposed SemiFL by deriving its convergence upper bound. To reduce latency, a convergence-constrained SemiFL latency minimization problem is formulated. By decoupling the original problem into several sub-problems, iterative algorithms are designed to solve them efficiently. Finally, numerical simulations are conducted to verify the effectiveness of our proposed scheme in reducing latency and guaranteeing the identification accuracy.
    摘要 为了处理互联网器(IoT)网络中巨大数据的实时处理,保护用户隐私,联邦学习(FL)被视为一种可能的技术。然而,FL的延迟增加了许多,这是由于深度神经网络中参数的增加和IoT设备的计算和通信能力的限制。为解决这个问题,我们提出了半联邦学习(SemiFL)模式。在这种模式下,每个小基站收集自己服务的感知器的原始数据,并在本地进行缩减模型的训练。然后,通过空中计算,全球集成本地梯度的全球汇总。我们首先分析了提议的SemiFL性能,并derive其 convergence upper bound。为了降低延迟,我们提出了一个基于泛化的SemiFL延迟最小化问题。通过分解原始问题,我们设计了高效的迭代算法来解决它们。最后,我们通过数值仿真来验证我们的提议的有效性,降低延迟,并保证标识精度。

Enabling Energy-Efficiency in Massive-MIMO: A Scalable Low-Complexity Decoder for Generalized Quadrature Spatial Modulation

  • paper_url: http://arxiv.org/abs/2310.02545
  • repo_url: None
  • paper_authors: Hyeon Seok Rou, Giuseppe Thadeu Freitas de Abreu, David González G., Osvaldo Gonsa
  • for: 提高无线系统的能量和频率效率
  • methods: 使用新的准则和算法,包括向量化 Gaussian belief propagation(GaBP)算法和单元向量分解(UVD)
  • results: 在计算机模拟中,包括32个发射天线的系统,实现了高能量和频率效率,展示了该方法在true massive MIMO设置中的潜在潜力。
    Abstract Generalized quadrature spatial modulation (GQSM) schemes are known to achieve high energy- and spectral- efficiencies by modulating information both in transmitted symbols and in coded combinatorial activations of subsets of multiple transmit antennas. A challenge of the approach is, however, the decoding complexity which scales with the efficiency of the scheme. In order to circumvent this bottleneck and enable high-performance and feasible GQSM in massive multiple-input multiple-output (mMIMO) scenarios, we propose a novel decoding algorithm which enjoys a complexity order that is independent of the combinatorial factor. This remarkable feature of the proposed decoder is a consequence of a novel vectorized Gaussian belief propagation (GaBP) algorithm, here contributed, whose message passing (MP) rules leverage both pilot symbols and the unit vector decomposition (UVD) of the GQSM signal structure. The effectiveness of the proposed UVD-GaBP method is illustrated via computer simulations including numerical results for systems of a size never before reported in related literature (up to 32 transmit antennas), which demonstrates the potential of the approach in paving the way towards high energy and spectral efficiency for wireless systems in a truly mMIMO setting.
    摘要 通用 quadrature 空间模ulation(GQSM)策略已经知道可以实现高能量和频率效率,但是这种方法的解码复杂度与策略的效率成线性关系。为了缓解这个瓶颈并实现高性能可行的GQSM,我们提出了一种新的解码算法,其复杂度随着策略的效率而变化。这一特点是我们提出的解码器的一个重要特点,它基于一种新的vectorized Gaussian belief propagation(GaBP)算法,该算法利用了传输符号和GQSM信号结构的unit vector decomposition(UVD)。我们通过计算机实验,包括数字结果,证明了该方法的有效性,并且可以在相关文献中找到相应的实验结果。这些结果表明了我们的方法在大规模mMIMO场景下具有很高的能量和频率效率。