results: near-field region可以实现宽频-like S&C 功能，包括信号复用和距离探测，以及在高速移动 S&C 场景中实现不可能的宽频功能。Abstract
This article re-examines integrated sensing and communication (ISAC) systems operating in the near-field region of a large antenna array while exploiting a large bandwidth. We first reveal the fundamental characteristics of wideband sensing and communication (S&C) channels and highlight the key changes that occur during the transition from the far-field to the near-field region. Specifically, there are two fundamental changes in the near-field region: strong angular-delay correlation and element-specific Doppler frequencies. It is highlighted that the near-field effect can enable the wideband-like S&C functionalities in terms of signal multiplexing and range sensing due to the strong angular-delay correlation, thus allowing the trading of large antenna arrays for large bandwidths. Furthermore, it also introduces the wideband-unattainable functionalities in high mobility S&C scenarios by leveraging the element-specific Doppler frequencies. We then delineate certain paradigm shifts in thinking required to advance toward near-field wideband ISAC systems, with a particular emphasis on resource allocation, antenna array arrangement, and transceiver architecture. Lastly, some other promising directions are discussed.
摘要
Vital Signs Estimation Using a 26 GHz Multi-Beam Communication Testbed
results: 测试结果显示，在单人场景下， breath rate和heart rate的估计 error 可以达到2 beat/分钟以下，而在多人场景下，可以分别提取出每个人的血气监测数据。这些结果表明，该系统可以准确地检测人体血气监测，并且可以在不同的场景下进行无接触的监测。Abstract
This paper presents a novel pipeline for vital sign monitoring using a 26 GHz multi-beam communication testbed. In context of Joint Communication and Sensing (JCAS), the advanced communication capability at millimeter-wave bands is comparable to the radio resource of radars and is promising to sense the surrounding environment. Being able to communicate and sense the vital sign of humans present in the environment will enable new vertical services of telecommunication, i.e., remote health monitoring. The proposed processing pipeline leverages spatially orthogonal beams to estimate the vital sign - breath rate and heart rate - of single and multiple persons in static scenarios from the raw Channel State Information samples. We consider both monostatic and bistatic sensing scenarios. For monostatic scenario, we employ the phase time-frequency calibration and Discrete Wavelet Transform to improve the performance compared to the conventional Fast Fourier Transform based methods. For bistatic scenario, we use K-means clustering algorithm to extract multi-person vital signs due to the distinct frequency-domain signal feature between single and multi-person scenarios. The results show that the estimated breath rate and heart rate reach below 2 beats per minute (bpm) error compared to the reference captured by on-body sensor for the single-person monostatic sensing scenario with body-transceiver distance up to 2 m, and the two-person bistatic sensing scenario with BS-UE distance up to 4 m. The presented work does not optimize the OFDM waveform parameters for sensing; it demonstrates a promising JCAS proof-of-concept in contact-free vital sign monitoring using mmWave multi-beam communication systems.
摘要
Link Streams as a Generalization of Graphs and Time Series
results: 本文表明了链流可以看作是时间序列的扩展，并开展了链流上的信号处理概念的扩展。Abstract
A link stream is a set of possibly weighted triplets (t, u, v) modeling that u and v interacted at time t. Link streams offer an effective model for datasets containing both temporal and relational information, making their proper analysis crucial in many applications. They are commonly regarded as sequences of graphs or collections of time series. Yet, a recent seminal work demonstrated that link streams are more general objects of which graphs are only particular cases. It therefore started the construction of a dedicated formalism for link streams by extending graph theory. In this work, we contribute to the development of this formalism by showing that link streams also generalize time series. In particular, we show that a link stream corresponds to a time-series extended to a relational dimension, which opens the door to also extend the framework of signal processing to link streams. We therefore develop extensions of numerous signal concepts to link streams: from elementary ones like energy, correlation, and differentiation, to more advanced ones like Fourier transform and filters.
摘要
一个链流是一组可能权重的三元组（t, u, v），表示在时间t上u和v之间的交互。链流提供了包含时间和关系信息的数据集模型，其分析在许多应用中非常重要。它们通常被视为时间序列或图集。然而，一篇最近的著名论文表明，链流是图集的更一般的对象。因此，它开始了链流的专门 формальismus的建构，通过扩展图论。在这项工作中，我们贡献了链流 formalism的发展，并证明了链流也拓展了时间序列。具体来说，一个链流对应于一个扩展到关系维度的时间序列，这开门了将信号处理框架扩展到链流的可能性。因此，我们开发了链流上许多信号概念的扩展：从基础的一些如能量、相关性和导数，到更高级的一些如傅里叶变换和筛选器。