results: 数值分析证明了这种方法可以大大提高覆盖范围，并且可以将多个小型智能表面组合成大型智能表面。Abstract
A reconfigurable intelligent surface (RIS) consists of a large number of low-cost elements that can control the propagation environment seen from a transmitter by intelligently applying phase shifts to impinging signals before reflection. This paper studies an RIS-assisted communication system where a transmitter wants to transmit a common signal to many users residing in a wide angular area. To cover this sector uniformly, the RIS needs to radiate a broad beam with a spatially flat array factor, instead of a narrow beam as normally considered. To achieve this, we propose to use a dual-polarized RIS consisting of elements with orthogonal polarizations and show that the RIS can produce a broad beam if the phase shift configuration vectors in the two polarizations form a so-called Golay complementary sequence pair. By utilizing their properties, we also present a method for constructing configuration for large RISs from smaller ones, while preserving the broad radiation pattern of the smaller RIS. The numerical results corroborate the mathematical analyses and highlight the greatly improved coverage properties.
摘要
一个可重新配置智能表面（RIS）由一大量低成本元素组成，可以控制传输器所看到的媒介传播环境，通过智能应用相位偏移到反射的信号前。这篇论文研究了一种由RIS支持的通信系统，在这种系统中，发送器想要将通信信号传输给覆盖广泛的用户群，这些用户群居住在一个宽角度区域中。为了覆盖这个领域，RIS需要发射一个广泛的束，而不是通常考虑的窄束。为了实现这一目标，我们提议使用双极化RIS，其元素具有正交的极化。我们表明，如果相位配置向量在两个极化中形成一个叫做高级别补做对的序列， то么RIS就可以生成一个广泛的束。此外，我们还提出了一种使用这种特性来构建大型RIS从小RIS中的方法，保持小RIS的广泛束 radiation 特性。数值结果证明了数学分析结果，并将广泛覆盖性得到了显著提高。
UAV Formation Optimization for Communication-assisted InSAR Sensing
results: 研究结果显示，采用 alternate optimization（AO）技术和successive convex approximation（SCA）可以最大化InSAR覆盖率，同时满足所有InSAR特定的探测和通信性能指标。Abstract
Interferometric synthetic aperture radar (InSAR) is an increasingly important remote sensing technique that enables three-dimensional (3D) sensing applications such as the generation of accurate digital elevation models (DEMs). In this paper, we investigate the joint formation and communication resource allocation optimization for a system comprising two unmanned aerial vehicles (UAVs) to perform InSAR sensing and to transfer the acquired data to the ground. To this end, we adopt as sensing performance metrics the interferometric coherence, i.e., the local correlation between the two co-registered UAV radar images, and the height of ambiguity (HoA), which together are a measure for the accuracy with which the InSAR system can estimate the height of ground objects. In addition, an analytical expression for the coverage of the considered InSAR sensing system is derived. Our objective is to maximize the InSAR coverage while satisfying all relevant InSAR-specific sensing and communication performance metrics. To tackle the non-convexity of the formulated optimization problem, we employ alternating optimization (AO) techniques combined with successive convex approximation (SCA). Our simulation results reveal that the resulting resource allocation algorithm outperforms two benchmark schemes in terms of InSAR coverage while satisfying all sensing and real-time communication requirements. Furthermore, we highlight the importance of efficient communication resource allocation in facilitating real-time sensing and unveil the trade-off between InSAR height estimation accuracy and coverage.
摘要
<>双无人航空器（UAV）探测双成像雷达（InSAR）系统的资源分配优化，以提高三维（3D）探测应用的精度。在本文中，我们将 investigate InSAR探测系统的共同形成和通信资源分配优化，以便两架UAV通过彼此联合探测来传输探测数据到地面。我们采用了干扰合成射频干扰（InSAR）探测系统的测试表现指标，包括干扰相关性（local correlation）和高程槽（HoA），这些指标共同测量干扰系统对地面物体高度的准确估计。此外，我们Derive an analytical expression for the coverage of the considered InSAR sensing system.我们的目标是将InSAR覆盖范围最大化，同时满足所有相关的InSAR特有探测和通信性能指标。为了解决干扰合成射频探测系统的非对称问题，我们使用了alternating optimization（AO）技术和Successive Convex Approximation（SCA）。我们的实验结果显示，所得的资源分配算法比两个底线方案更好，在满足所有探测和实时通信需求的情况下，提高InSAR覆盖范围。此外，我们阐述了实时探测和干扰系统之间的贡献相互作用，以及探测高度估计精度和覆盖范围之间的贡献贸易。<>
A Generalized Framework for Pulse-Shaping on Delay-Doppler Plane
results: 我们的仪器实验结果证明了我们的数学 derivations 和主张的正确性，同时也证明了 ZGs 在 OOB 减少和 BER 性能提高方面的效果。Abstract
The primary objective of this paper is to establish a generalized framework for pulse-shaping on the delay-Doppler plane. To this end, we classify delay-Doppler pulse-shaping techniques into two types, namely, circular and linear pulse-shaping. This paves the way towards the development of a generalized pulse-shaping framework. Our generalized framework provides the opportunity to compare different pulse-shaping techniques under the same umbrella while bringing new insights into their properties. In particular, our derivations based on this framework reveal that the recently emerged waveform orthogonal delay-Doppler multiplexing modulation (ODDM) is a linear pulse-shaping technique. By presenting ODDM under our generalized framework, we clearly explain the observed staircase behavior of its spectrum which has not been previously reported in the literature. Another contribution of this paper is proposal of a simple out-of-band (OOB) emission reduction technique by inserting a small number of zero-guard (ZG) symbols along the delay dimension of the circularly pulse-shaped signals. Additionally, inserting the zero-guards improves the bit-error-rate (BER) performance of both circular and linear pulse-shaping techniques. Finally, our simulation results confirm the validity of our mathematical derivations, claims and the effectiveness of the ZGs in OOB reduction and BER performance improvement.
摘要
主要目标 OF 这篇论文是建立一个通用的射频平面上的振荡形态框架。为达到这个目标，我们将延迟-Doppler 振荡技术分为两类：圆形振荡和直线振荡。这些分类提供了一个通用的振荡形态框架，可以对不同的振荡技术进行比较，并为其Properties 提供新的看法。具体来说，我们的 derivations 表明，最近出现的振荡 Ortogonal delay-Doppler multiplexing modulation (ODDM) 是一种直线振荡技术。通过将 ODDM 放入我们的通用框架中，我们可以清晰地解释 literature 中未曾报道的 ODDM 谱图的楼梯结构。此外，我们还提出了一种简单的出带 Emission reduction 技术，通过在圆振荡信号中添加一些零卫星（ZG）符号来减少带外干扰。此外，添加 ZG 符号还可以提高圆振荡和直线振荡技术的比特错误率（BER）性能。最后，我们的仿真结果证明了我们的数学 derivations 和主张的正确性，以及 ZG 符号在 OOB 减少和 BER 性能提高中的效果。
Symbol-Error Probability Constrained Power Minimization for Reconfigurable Intelligent Surfaces-based Passive Transmitter
results: 该论文通过使用 bisecting 方法和里曼尼昂 conjugate gradient 算法解决了这个问题。数值结果表明，该方法可以有效地减少 transmit power，并且适用于不同的 symbol-error probability 要求。Abstract
This study considers a virtual multiuser multiple-input multiple-output system with PSK modulation realized via the reconfigurable intelligent surface-based passive transmitter setup. Under this framework, the study derives the formulation for the union-bound symbol-error probability, which is an upper bound on the actual symbol-error probability. Based on this, a symbol-level precoding power minimization problem under the condition that the union-bound symbol-error probability is below a given requirement is proposed. The problem is formulated as a constrained optimization on an oblique manifold, and solved via a bisection method. The method consists of successively optimizing transmit power while evaluating the feasibility of the union-bound symbol-error probability requisite by solving, via the Riemannian conjugate gradient algorithm, an auxiliary problem dependent only on the reflection coefficients of the reconfigurable intelligent surface elements. Numerical results demonstrate the effectiveness of the proposed approach in minimizing the transmit power for different symbol-error probability requirements.
摘要
Energy-efficient Beamforming for RISs-aided Communications: Gradient Based Meta Learning
results: 在 simulations 中，GMLB 能够高于典型的 alternate 优化算法，并且能够减少两个数量级的能耗。Abstract
Reconfigurable intelligent surfaces (RISs) have become a promising technology to meet the requirements of energy efficiency and scalability in future six-generation (6G) communications. However, a significant challenge in RISs-aided communications is the joint optimization of active and passive beamforming at base stations (BSs) and RISs respectively. Specifically, the main difficulty is attributed to the highly non-convex optimization space of beamforming matrices at both BSs and RISs, as well as the diversity and mobility of communication scenarios. To address this, we present a greenly gradient based meta learning beamforming (GMLB) approach. Unlike traditional deep learning based methods which take channel information directly as input, GMLB feeds the gradient of sum rate into neural networks. Coherently, we design a differential regulator to address the phase shift optimization of RISs. Moreover, we use the meta learning to iteratively optimize the beamforming matrices of BSs and RISs. These techniques make the proposed method to work well without requiring energy-consuming pre-training. Simulations show that GMLB could achieve higher sum rate than that of typical alternating optimization algorithms with the energy consumption by two orders of magnitude less.
摘要
现代化智能表面技术（RIS）已成为未来六代通信（6G）的一种有前途的技术，以满足能效性和可扩展性的需求。然而，RIS协助通信中存在一个主要挑战，即BS和RIS的活动和被动扫描矩阵优化的共同优化。具体来说，这是因为扫描矩阵的优化空间具有非 convex 性，以及通信场景的多样性和移动性。为解决这个问题，我们提出了一种绿色梯度基于元学习扫描矩阵优化（GMLB）方法。不同于传统的深度学习基于方法，GMLB 将扫描矩阵的梯度Feed into神经网络。此外，我们设计了一种差分调制器来处理RIS的相位优化。此外，我们使用元学习来逐次优化BS和RIS的扫描矩阵。这些技术使得我们的方法可以不需要耗费能量劳动性的预训练。实验显示，GMLB 可以在能效性方面高于传统的交互优化算法，并且能够降低能 consumption by two orders of magnitude。
Multiuser Resource Allocation for Semantic-Relay-Aided Text Transmissions
results: 提出一种优化多用户资源分配问题的算法，以提高多用户文本传输效率，并经过数学实验证明其高质量优化解决方案的有效性Abstract
Semantic communication (SemCom) is an emerging technology that extracts useful meaning from data and sends only relevant semantic information. Thus, it has the great potential to improve the spectrum efficiency of conventional wireless systems with bit transmissions, especially in low signal-to-noise ratio (SNR) and small bandwidth regions. However, the existing works have mostly overlooked the constraints of mobile devices, which may not have sufficient capabilities to implement resource-demanding semantic encoder/decoder based on deep learning. To address this issue, we propose in this paper a new semantic relay (SemRelay), which is equipped with a semantic receiver to assist multiuser text transmissions. Specifically, the SemRelay decodes semantic information from a base station and forwards it to the users using conventional bit transmission, hence effectively improving text transmission efficiency. To study the multiuser resource allocation, we formulate an optimization problem to maximize the multiuser weighted sum-rate by jointly designing the SemRelay transmit power allocation and system bandwidth allocation. Although this problem is non-convex and hence challenging to solve, we propose an efficient algorithm to obtain its high-quality suboptimal solution by using the block coordinate descent method. Last, numerical results show the effectiveness of the proposed algorithm as well as superior performance of the proposed SemRelay over the conventional decode-and-forward (DF) relay, especially in small bandwidth region.
摘要
semantic communication (SemCom) 是一种出现在技术中，它从数据中提取有用的意义并仅发送相关的semantic信息。因此，它在传统的无线系统中的频率效率可以得到改进，特别是在低信号响应率（SNR）和小带宽区域。然而，现有的工作都很少考虑了移动设备的限制，它们可能没有充分的能力来实现深度学习基于的 semantic编码/解码器。为解决这个问题，我们在本文提出了一种新的semantic relay（SemRelay），它装备了semantic接收器，以帮助多用户文本传输。具体来说，SemRelay从基站中解码semantic信息，并将其转发给用户 mediante conventional bit transmission，从而有效地提高文本传输效率。为了研究多用户资源分配，我们建立了一个优化问题，以最大化多用户权重合并率。尽管这个问题是非核心的，但我们提出了一种高效的算法，使用块均衡下降法来获得其高质量的偏函数解。最后，数值结果表明了提案的算法的有效性以及SemRelay对传统的decode-and-forward（DF）关系的superior性，特别是在小带宽区域。
Coexistence of OTFS Modulation With OFDM-based Communication Systems
methods: 我们首先 derivated OTFS signal的输入输出关系（IOR），并考虑了CPs的不同长度对OTFS信号的影响。我们还提出了一种基于嵌入式测试点的渠道估计技术，以便在合作系统中准确地 caracterize the channel。
results: 我们通过数字结果显示，在忽略CPs的不同长度时，OTFS信号在共存系统中的错误比率性能会下降。此外，我们还证明了我们提出的渠道估计技术在OTFS信号中的共存系统中能够超过当前状态的阈值基于渠道估计技术。Abstract
This study examines the coexistence of orthogonal time-frequency space (OTFS) modulation with current fourth- and fifth-generation (4G/5G) wireless communication systems that primarily use orthogonal frequency-division multiplexing (OFDM) waveforms. We first derive the input-output-relation (IOR) of OTFS when it coexists with an OFDM system while considering the impact of unequal lengths of the cyclic prefixes (CPs) in the OTFS signal. We show analytically that the inclusion of multiple CPs to the OTFS signal results in the effective sampled delay-Doppler (DD) domain channel response to be less sparse. We also show that the effective DD domain channel coefficients for OTFS in coexisting systems are influenced by the unequal lengths of the CPs. Subsequently, we propose an embedded pilot-aided channel estimation (CE) technique for OTFS in coexisting systems that leverages the derived IOR for accurate channel characterization. Using numerical results, we show that ignoring the impact of unequal lengths of the CPs during signal detection can degrade the bit error rate performance of OTFS in coexisting systems. We also show that the proposed CE technique for OTFS in coexisting systems outperforms the state-of-the-art threshold-based CE technique.
摘要
Translation:这个研究研究了 fourth-和 fifth-generation (4G/5G) 无线通信系统中 orthogonal time-frequency space (OTFS) 模ulation的共存。我们首先 derive OTFS 在共存系统中的输入-输出关系 (IOR)，并考虑了 OTFS 信号中不同的循环前缀 (CP) 的不同长度对共存系统的影响。我们显示了 analytically ，将多个 CP 添加到 OTFS 信号中会使共存系统的快速傅立叶频域频率响应变得更加稀疏。此外，我们还显示了 OTFS 在共存系统中的有效快速傅立叶频域通道响应被 CP 的不同长度所影响。然后，我们提出了一种基于嵌入式测试器的 OTFS 在共存系统中的频道估计 (CE) 技术，该技术利用了我们Derived IOR 实现了准确的频道特征化。使用数字结果，我们显示了忽略共存系统中 CP 的不同长度时 during signal detection 可能会导致 OTFS 的比特错误率性能下降。此外，我们还显示了我们提出的 CE 技术在共存系统中的 OTFS 性能高于当前的阈值基于 CE 技术。
Joint Design of Coding and Modulation for Digital Over-the-Air Computation
For: 本文提出了一种基于数字系统的空中计算（AirComp）传输技术，以提高AirComp在复杂无线环境中的可靠性和可扩展性。* Methods: 本文提出了一种基于非二进制LDPC编码的通道编码方案，以增强AirComp的错误修复能力。此外，本文还提出了一种基于阈值编码技术的数字化模调方案，以实现多发送器的数量之和。* Results: 本文提供了仪表结果，以证明提议的设计的可行性和性能。Abstract
Due to its high communication efficiency, over-the-air computation (AirComp) has been expected to carry out various computing tasks in the next-generation wireless networks. However, up to now, most applications of AirComp are explored in the analog domain, which limits the capability of AirComp in resisting the complex wireless environment, not to mention to integrate the AirComp technique to the existing universal communication standards, most of which are based on the digital system. In this paper, we propose a joint design of channel coding and digital modulation for digital AirComp transmission to attempt to reinforce the foundation for the application of AirComp in the digital system. Specifically, we first propose a non-binary LDPC-based channel coding scheme to enhance the error-correction capability of AirComp. Then, a digital modulation scheme is proposed to achieve the number summation from multiple transmitters via the lattice coding technique. We also provide simulation results to demonstrate the feasibility and the performance of the proposed design.
摘要
由于它的高通信效率，无线计算（AirComp）已被预期在下一代无线网络中执行多种计算任务。然而，至今为止，大多数AirComp应用都是在分析频域中进行的，这限制了AirComp在复杂无线环境中的可扩展性，更不能说明将AirComp技术与现有的通用通信标准集成。在这篇论文中，我们提议一种合理的渠道编码和数字化调制的结合方案，以强化AirComp在数字系统中的基础。具体来说，我们首先提议一种非二进制LDPC编码方案，以增强AirComp的错误恢复能力。然后，我们提议一种数字化调制方案，通过笛卡尔编码技术实现多个发送器的数字加法。我们还提供了临场实验结果，以证明提议的设计的可行性和性能。
Secure Rate-Splitting Multiple Access Transmissions in LMS Systems
for: investigate the secure delivery performance of the rate-splitting multiple access scheme in land mobile satellite (LMS) systems
methods: adopt Maximum ratio transmission (MRT) and matched-filtering (MF) precoding techniques at the satellite, based on the estimated LMS channels suffering from the Shadowed-Rician fading
results: derive closed-form expressions for the ergodic rates for decoding the common messages (CM) and private messages (PM) at the intended user, as well as the ergodic secrecy rate against eavesdropping, and provide numerical results to validate the analysis models and show interesting comparisons.Here’s the summary in Traditional Chinese:
results: derivate 关于传输率的关键表达式，包括传输率、私人讯息传输率和机密私人讯息传输率，并提供数值结果来验证分析模型，以及展示一些有趣的比较I hope this helps!Abstract
This letter investigates the secure delivery performance of the rate-splitting multiple access scheme in land mobile satellite (LMS) systems, considering that the private messages intended by a terminal can be eavesdropped by any others from the broadcast signals. Specifically, the considered system has an N-antenna satellite and numerous single-antenna land users. Maximum ratio transmission (MRT) and matched-filtering (MF) precoding techniques are adopted at the satellite separately for the common messages (CMs) and for the private messages (PMs), which are both implemented based on the estimated LMS channels suffering from the Shadowed-Rician fading. Then, closed-form expressions are derived for the ergodic rates for decoding the CM, and for decoding the PM at the intended user respectively, and more importantly, we also derive the ergodic secrecy rate against eavesdropping. Finally, numerical results are provided to validate the correctness of the proposed analysis models, as well as to show some interesting comparisons.
摘要
这封信函通过研究在陆地手机卫星（LMS）系统中的稳定交付性表现来调查率分访问方案，具体来说，系统具有N个天线的卫星和多个单天线的地面用户。在卫星上，我们采用最大比率传输（MRT）和匹配滤波（MF） precoding技术来进行通用消息（CM）和专用消息（PM）的编码，这两种技术都基于卫星通道的估计，卫星通道受到阴影-瑞德抽象扰干。然后，我们得到了对CM的有效比特率和对PM的有效比特率的关闭式表达，以及对听到者进行窃听的安全秘密率。最后，我们提供了数值结果来验证我们的分析模型，并且展示了一些有趣的比较。
Compressive Sensing-Based Grant-Free Massive Access for 6G Massive Communication
results: 本文预测了 grant-free 巨量访问的未来研究方向，包括巨量访问技术的进一步开发和应用。Abstract
The advent of the sixth-generation (6G) of wireless communications has given rise to the necessity to connect vast quantities of heterogeneous wireless devices, which requires advanced system capabilities far beyond existing network architectures. In particular, such massive communication has been recognized as a prime driver that can empower the 6G vision of future ubiquitous connectivity, supporting Internet of Human-Machine-Things for which massive access is critical. This paper surveys the most recent advances toward massive access in both academic and industry communities, focusing primarily on the promising compressive sensing-based grant-free massive access paradigm. We first specify the limitations of existing random access schemes and reveal that the practical implementation of massive communication relies on a dramatically different random access paradigm from the current ones mainly designed for human-centric communications. Then, a compressive sensing-based grant-free massive access roadmap is presented, where the evolutions from single-antenna to large-scale antenna array-based base stations, from single-station to cooperative massive multiple-input multiple-output systems, and from unsourced to sourced random access scenarios are detailed. Finally, we discuss the key challenges and open issues to shed light on the potential future research directions of grant-free massive access.
摘要
六代无线通信技术的出现（6G）已经导致了迫切需要连接各种不同的无线设备，这需要进一步的系统功能，远超现有网络架构。特别是，这种大规模通信被认为是未来无限连接性的核心驱动力，支持人机机器互联网，它们的大规模访问是关键。本文 survey了最新的大规模访问技术发展，主要关注 compressive sensing 基于的免费大规模访问方案。我们首先描述了现有随机访问方案的限制，并显示了现有随机访问方案主要是为人类通信而设计的。然后，我们提出了 compressive sensing 基于的免费大规模访问路线图，包括从单antenna到大规模天线阵列基站、从单站到合作大规模多输入多出力系统、和从无源到源随机访问场景的演化。最后，我们讨论了关键挑战和未解决问题，以照明未来研究方向。
One Signal-Noise Separation based Wiener Filter for Magnetogastrogram
for: 这 paper 是为了提高Magnetogastrogram (MGG) signal detection中的噪声抑制和信号分离。
methods: 这 paper 使用了一种新的信号处理框架，即基于信号噪声分离的维ener filters (SNSWF)，以提高维ener filters 输出的噪声比例。
results: 使用SNSWFfilter，可以提高MGG signal detection中的信号噪声比例，相比 классический维ener filters，SNSWFfilter 的filter SNR高出16.7 dB。Abstract
Magnetogastrogram (MGG) signal frequency is about 0.05 Hz, the low-frequency environmental noise interference is serious and can be several times stronger in magnitude than the signals of interest and may severely impede the extraction of relevant information. Wiener filter is one classic denoising solution for biomagnetic applications. Since the reference channels are usually placed not far enough from the biomagnetic sources under test, they will inevitably detect the signals and the Wiener filters may produce ill-conditioned solutions. Considering the solutions to improve the signal-to-noise ratio (SNR) of Wiener filter output, there are few methods to separate the signals from the noises of the reference signal at the filter input. In this paper, a new signal processing framework called signal-noise separation based Wiener filter (SNSWF) is proposed that it separates the main noise as the input signal of the filter to improve the output SNR of Wiener filter. The filter was successfully applied to the noise suppression for MGG signal detection. Using the SNSWF, the filter SNR is 16.7 dB better than the classic Wiener filter.
摘要
магнитогастрограм（MGG）信号频率约为0.05Hz，低频环境干扰强度较高，可能比有兴趣信号强度多倍，严重阻碍了有关信息的提取。wiener filter是生物磁学应用中一种经典的干扰除解决方案。由于参照通道通常不会在测试biomagnetic sources的位置够近，因此它们会检测信号，wiener filter可能会生成不正确的解决方案。为了提高wiener filter输出的信号噪听比（SNR），有几种方法可以从filter输入分离信号和噪声。在本文中，一种新的信号处理框架被提出，称为信号噪声分离based Wiener filter（SNSWF）。它可以将主要噪声作为输入信号，以提高wiener filter输出的SNR。这个filter成功应用于MGG信号检测中的噪声抑制。使用SNSWF，filter SNR比 классиwiener filter高16.7dB。