paper_authors: Abdolrasoul Sakhaei Gharagezlou, Nima Imani, Mahdi Nangir
For: 这个研究目的是实现5G通信系统中的能源和频率利用效率。* Methods: 这个研究使用大量多input多output（MIMO）系统，并考虑了该系统中的安全传输问题。* Results: 研究发现，透过选择最佳天线数量和细分方法，可以实现最大化系统的安全能源效率。另外，这个研究还提出了四个迭代算法来提供量化评估。Abstract
One of the most important challenges in the fifth generation (5G) of telecommunication systems is the efficiency of energy and spectrum. Massive multiple-input multiple-output (MIMO) systems have been proposed by researchers to resolve existing challenges. In the proposed system model of this paper, there is a base station (BS) around which several users and an eavesdropper (EVA) are evenly distributed. The information transmitted between BS and users is disrupted by an EVA, which highlights the importance of secure transfer. This paper analyzes secure energy efficiency (EE) of a massive MIMO system, and its purpose is to maximize the secure EE of the system. Several scenarios are considered to evaluate achieving the desired goal. To maximize the secure EE, selecting optimal number of antennas and cell division methods are employed. Each of these two methods is applied in a system with the maximum ratio transmission (MRT) and the zero forcing (ZF) precodings, and then the problem is solved. Maximum transmission power and minimum secure rate for users insert limitations to the optimization problem. Channel state information (CSI) is generally imperfect for users in any method, while CSI of the EVA is considered perfect as the worst case. Four iterative algorithms are designed to provide numerical assessments. The first algorithm calculates the optimal power of users without utilizing existing methods, the second one is related to the cell division method, the third one is based on the strategy of selecting optimal number of antennas, and forth one is based on a hybrid strategy.
摘要
一个重要的挑战在 fifth generation (5G) 通信系统中是能源和频谱的效率。大量多输入多输出 (MIMO) 系统已经被研究人员提议以解决现有的挑战。本文中的系统模型中有一个基站 (BS)，周围有多个用户和一个伪装者 (EVA)。BS 与用户之间的信息被伪装者破坏，这 highlights 了安全传输的重要性。本文分析了大规模 MIMO 系统的安全能效 (EE)，目的是最大化系统的安全EE。多种场景被考虑以评估目标。为了最大化安全EE，选择最佳的天线数和 Cell division 方法是使用的。每种这两种方法都在使用最大 переда信号强度和零干扰 (ZF) 预编码时被应用，然后解决问题。最大传输功率和最小安全速率为用户设置限制了优化问题。用户在任何方法中都有不完整的通道状态信息 (CSI)，而 EVA 的 CSI 被视为最坏情况。四种迭代算法被设计来提供数值评估。第一个算法计算用户的最佳功率，不使用现有方法；第二个算法关于 Cell division 方法；第三个算法基于选择最佳天线数的策略；第四个算法基于混合策略。
Low-Complexity Joint Beamforming for RIS-Assisted MU-MISO Systems Based on Model-Driven Deep Learning
results: 比较存在 estado-of-the-art算法，提案的算法在复杂度和吞吐量方面表现更好，特别是使用模型驱动深度学习approach可以大幅降低运行时间。Abstract
Reconfigurable intelligent surfaces (RIS) can improve signal propagation environments by adjusting the phase of the incident signal. However, optimizing the phase shifts jointly with the beamforming vector at the access point is challenging due to the non-convex objective function and constraints. In this study, we propose an algorithm based on weighted minimum mean square error optimization and power iteration to maximize the weighted sum rate (WSR) of a RIS-assisted downlink multi-user multiple-input single-output system. To further improve performance, a model-driven deep learning (DL) approach is designed, where trainable variables and graph neural networks are introduced to accelerate the convergence of the proposed algorithm. We also extend the proposed method to include beamforming with imperfect channel state information and derive a two-timescale stochastic optimization algorithm. Simulation results show that the proposed algorithm outperforms state-of-the-art algorithms in terms of complexity and WSR. Specifically, the model-driven DL approach has a runtime that is approximately 3% of the state-of-the-art algorithm to achieve the same performance. Additionally, the proposed algorithm with 2-bit phase shifters outperforms the compared algorithm with continuous phase shift.
摘要
可变智能表面（RIS）可以改善信号传播环境中的信号相位。然而，在访问点上同时优化相位偏移和扫描向量是复杂的，因为目标函数是非对称的。在本研究中，我们提出了基于最小二乘平均误差优化和电力迭代的算法，以提高RIS协助的下行多用户多输入单输出系统的权重和平均数据率（WSR）。为了进一步改善性能，我们设计了基于模型驱动的深度学习（DL）方法，其中引入了可学习变量和图神经网络，以加速我们提出的算法的整合。此外，我们将提案扩展到包括不完美通道状态信息的扫描方法，并 derivate了两个时间步骤的随机优化算法。实验结果表明，我们的算法在复杂度和WSR方面与状态的算法相比有较好的性能。具体来说，使用模型驱动的DL方法的运行时间约为状态的算法的3%，而且我们的算法使用2比特相位偏移器可以超过与连续相位偏移器相比的性能。
paper_authors: Wang Zhaohan for: This research paper aims to mitigate the noise emissions produced by electrical appliances, such as a coffee machine, using cutting-edge active noise control methodologies.methods: The study employs a modified Filtered-X Least Mean Square (FXLMS) algorithm, which generates an anti-noise waveform by utilizing measurements from both the reference microphone and the error microphone.results: The desired outcome of this approach is to achieve a residual noise level of zero, despite the challenge of conducting the experiment in an open space setting. The study provides an introduction to different Active Noise Control systems and algorithms, followed by simulations and experimental execution.Abstract
The objective of this research is to employ cutting-edge active noise control methodologies in order to mitigate the noise emissions produced by electrical appliances, such as a coffee machine. The algorithm utilized in this study is the modified Filtered-X Least Mean Square (FXLMS) algorithm. This algorithm aims to generate an anti-noise waveform by utilizing measurements from both the reference microphone and the error microphone. The desired outcome of this approach is to achieve a residual noise level of zero. The primary difficulty lies in conducting the experiment in an open space setting, as conventional active noise control systems are designed to function within enclosed environments, such as closed rooms or relatively confined spaces like the volume inside headphones. A validation test bench is established, employing the Sigma Studio software to oversee the entire system, with the ADAU1452 digital signal processor being chosen. This study presents an introduction to different Active Noise Control systems and algorithms, followed by the execution of simulations for representative techniques. Subsequently, this section provides a comprehensive account of the procedures involved in executing the experiments, followed by an exploration of potential avenues for further research.
摘要
研究目标是使用先进的活动噪声控制方法来减少电器设备（如咖啡机）发生的噪声泄露。这种算法是修改后的 Filtered-X Least Mean Square（FXLMS）算法。该算法利用参照 Microphone 和错误 Microphone 的测量值来生成一个反噪波形。 Desired outcome 是实现噪声水平为零。主要挑战在于在开放空间环境中进行实验，因为传统的活动噪声控制系统是为关闭空间（如室内或相对封闭的空间，如Headphones 中的volume）设计。我们建立了一个验证测试台，使用Sigma Studio 软件进行整个系统的监测，并选择了 ADAU1452 数字信号处理器。本文介绍了不同的活动噪声控制系统和算法，然后对代表性技术进行了 simulations。接着，这个部分提供了实验执行的详细过程，然后进行了潜在的进一步研究的探索。
Covariance-Based Activity Detection in Cooperative Multi-Cell Massive MIMO: Scaling Law and Efficient Algorithms
For: 这篇论文关注于多组多输入多Output（MIMO）系统中的协同活动检测问题。在这个系统中，活动设备对多个基站（BS）发送签章序列，并且BS们协同检测活动设备的签章序列。* Methods: 这篇论文使用了协同检测的方法，包括协同检测的概率模型和协同检测的数据分析方法。* Results: 这篇论文的结果显示，在多组MIMO系统中，签章序列的长度和签章序列的类型都会影响协同检测的正确率。此外，这篇论文还提出了两个高效的加速坐标下降（CD）算法，可以实现协同检测问题的解决。这两个算法都有优化的复杂度和解决方案。Abstract
This paper focuses on the covariance-based activity detection problem in a multi-cell massive multiple-input multiple-output (MIMO) system. In this system, active devices transmit their signature sequences to multiple base stations (BSs), and the BSs cooperatively detect the active devices based on the received signals. While the scaling law for the covariance-based activity detection in the single-cell scenario has been extensively analyzed in the literature, this paper aims to analyze the scaling law for the covariance-based activity detection in the multi-cell massive MIMO system. Specifically, this paper demonstrates a quadratic scaling law in the multi-cell system, under the assumption that the exponent in the classical path-loss model is greater than 2. This finding shows that, in the multi-cell MIMO system, the maximum number of active devices that can be detected correctly in each cell increases quadratically with the length of the signature sequence and decreases logarithmically with the number of cells (as the number of antennas tends to infinity). Moreover, in addition to analyzing the scaling law for the signature sequences randomly and uniformly distributed on a sphere, the paper also establishes the scaling law for signature sequences generated from a finite alphabet, which are easier to generate and store. Moreover, this paper proposes two efficient accelerated coordinate descent (CD) algorithms with a convergence guarantee for solving the device activity detection problem. The first algorithm reduces the complexity of CD by using an inexact coordinate update strategy. The second algorithm avoids unnecessary computations of CD by using an active set selection strategy. Simulation results show that the proposed algorithms exhibit excellent performance in terms of computational efficiency and detection error probability.
摘要
（注意：以下是简化中文翻译，并不是正式的学术论文翻译）这篇论文关注多个细胞大规模多输入多输出（MIMO）系统中的协同活动检测问题。在这个系统中，活动设备将其签名序列传输到多个基站（BS），BS们协同检测活动设备基于接收信号。而在单个细胞场景下， covariance-based 活动检测的扩展法已经广泛研究过，这篇论文想要分析多细胞系统中 covariance-based 活动检测的扩展法。具体来说，这篇论文显示在多细胞系统中，使用签名序列的长度和细胞数量（在无穷多antenna时）来检测活动设备的最大数量呈 quadratic 增长。此外，这篇论文还分析了在不同签名序列分布情况下的扩展法，并提出了两种高效的加速坐标下降算法（CD），以及它们在检测错误概率和计算效率方面的性能。
Active-Sensing-Based Beam Alignment for Near Field MIMO Communications
results: 比codebook-based beam alignment方法更快速地找到优化的发射器对，避免高训练负担 caused by beam sweeping，数学结果验证了提议方法的有效性Abstract
An active-sensing-based learning algorithm is proposed to solve the near-field beam alignment problem with the aid of wavenumber-domain transform matrices (WTMs). Specifically, WTMs can transform the antenna-domain channel into a sparse representation in the wavenumber domain. The dimensions of WTMs can be further reduced by exploiting the dominance of line-of-sight (LoS) links. By employing these lower-dimensional WTMs as mapping functions, the active-sensing-based algorithm is executed in the wavenumber domain, resulting in an acceleration of convergence. Compared with the codebook-based beam alignment methods, the proposed method finds the optimal beam pair in a ping-pong fashion, thus avoiding high training overheads caused by beam sweeping. Finally, the numerical results validate the effectiveness of the proposed method.
摘要
一种基于活动感测的学习算法是提出来解决近场束Alignment问题，通过使用幂数频率域变换矩阵（WTM）。特别是，WTM可以将天线频率域通道转换为稀疏表示。进一步地，通过利用直线视线（LoS）链接的主导性，可以降低WTM的维度。通过这些减少维度的WTM作为映射函数，在幂数频率域执行活动感测基本算法，从而加速吞吐量。与codebook-based beam alignment方法相比，提议方法可以快速找到最佳束对，因此避免了高训练负担，引起的扫描束对过程。最后，数值结果证明了提议方法的有效性。
From OTFS to DD-ISAC: Integrating Sensing and Communications in the Delay Doppler Domain
results: 论文表明，使用DD通信波形可以提高ISAC的性能，特别是在高速移动场景下。DD通信波形可以直接与雷达探测参数相互作用，并且可以提高雷达探测的准确率和平均平方误差（MSE）性能。Abstract
Next-generation vehicular networks are expected to provide the capability of robust environmental sensing in addition to reliable communications to meet intelligence requirements. A promising solution is the integrated sensing and communication (ISAC) technology, which performs both functionalities using the same spectrum and hardware resources. Most existing works on ISAC consider the Orthogonal Frequency Division Multiplexing (OFDM) waveform. Nevertheless, vehicle motion introduces Doppler shift, which breaks the subcarrier orthogonality and leads to performance degradation. The recently proposed Orthogonal Time Frequency Space (OTFS) modulation, which exploits various advantages of Delay Doppler (DD) channels, has been shown to support reliable communication in high-mobility scenarios. Moreover, the DD waveform can directly interact with radar sensing parameters, which are actually delay and Doppler shifts. This paper investigates the advantages of applying the DD communication waveform to ISAC. Specifically, we first provide a comprehensive overview of implementing DD communications, based on which several advantages of DD-ISAC over OFDM-based ISAC are revealed, including transceiver designs and the ambiguity function. Furthermore, a detailed performance comparison are presented, where the target detection probability and the mean squared error (MSE) performance are also studied. Finally, some challenges and opportunities of DD-ISAC are also provided.
摘要
Recently proposed orthogonal time frequency space (OTFS) modulation, which exploits various advantages of delay Doppler (DD) channels, has been shown to support reliable communication in high-mobility scenarios. Moreover, the DD waveform can directly interact with radar sensing parameters, which are actually delay and Doppler shifts. This paper investigates the advantages of applying the DD communication waveform to ISAC.Specifically, we first provide a comprehensive overview of implementing DD communications, based on which several advantages of DD-ISAC over OFDM-based ISAC are revealed, including transceiver designs and the ambiguity function. Furthermore, a detailed performance comparison is presented, where the target detection probability and the mean squared error (MSE) performance are also studied. Finally, some challenges and opportunities of DD-ISAC are also provided.Translation notes:* "vehicular networks" becomes "交通网络" (jiao tong wang luo)* "intelligence requirements" becomes "智能要求" (zhì neng yào qiú)* "integrated sensing and communication" becomes "集成探测通信" (jí chéng tàn cè tōng xì)* "Orthogonal Frequency Division Multiplexing" becomes "垂直频分多路复用" (shuāng zhì fēn fāng duō lù fù yòng)* "Doppler shift" becomes "多普勒移动" (duō pǔ lè yí dòng)* "delay Doppler" becomes "延迟多普勒" (jiān chái duō pǔ lè)* "orthogonal time frequency space" becomes "时频空间" (shí fēn kōng jiān)* "transceiver designs" becomes "传输设计" (chuán xiū jiè yì)* "ambiguity function" becomes "模糊函数" (mó hóu fäng xiàng)* "target detection probability" becomes "目标检测可能性" (mù zhì gǎn zhè kě néng xìng)* "mean squared error" becomes "平均方差" (píng jūn fāng biàn)
Angular-Distance Based Channel Estimation for Holographic MIMO
paper_authors: Yuanbin Chen, Ying Wang, Zhaocheng Wang, Zhu Han for:这篇论文探讨了束图多Input多Output（MIMO）系统的通道估计，具体来说是揭示了这种系统的通道估计问题与传统系统不同之处。methods:这篇论文使用了一种 Parametric Decomposition and Compressed Deconstruction（DeRe）框架，并提出了一种基于变分bayesian推断和消息传递（DeRe-VM）的高效算法，以实现对3D AED参数的精确探测和可Robust通道的重建。results:该论文的结果表明，提出的通道估计策略具有很好的Robust性，可以在不同的通道条件下进行正确的估计，并且与传统 benchmark 相比，表现出了更高的性能。Abstract
This paper investigates the channel estimation for holographic MIMO systems by unmasking their distinctions from the conventional one. Specifically, we elucidate that the channel estimation, subject to holographic MIMO's electromagnetically large antenna arrays, has to discriminate not only the angles of a user/scatterer but also its distance information, namely the three-dimensional (3D) azimuth and elevation angles plus the distance (AED) parameters. As the angular-domain representation fails to characterize the sparsity inherent in holographic MIMO channels, the tightly coupled 3D AED parameters are firstly decomposed for independently constructing their own covariance matrices. Then, the recovery of each individual parameter can be structured as a compressive sensing (CS) problem by harnessing the covariance matrix constructed. This pair of techniques contribute to a parametric decomposition and compressed deconstruction (DeRe) framework, along with a formulation of the maximum likelihood estimation for each parameter. Then, an efficient algorithm, namely DeRe-based variational Bayesian inference and message passing (DeRe-VM), is proposed for the sharp detection of the 3D AED parameters and the robust recovery of sparse channels. Finally, the proposed channel estimation regime is confirmed to be of great robustness in accommodating different channel conditions, regardless of the near-field and far-field contexts of a holographic MIMO system, as well as an improved performance in comparison to the state-of-the-art benchmarks.
摘要