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Introduction to the Modern Theory of Dynamical Systems

6G and beyond will fulfill the requirements of a fully connected world and provide ubiquitous wireless connectivity for all. Transformative solutions are expected to drive the surge for accommodating a rapidly growing number of intelligent devices and services. Major technological breakthroughs to achieve connectivity goals within 6G include: (i) a network operating at the THz band with much wider spectrum resources, (ii) intelligent communication environments that enable a wireless propagation environment with active signal transmission and reception, (iii) pervasive artificial intelligence, (iv) large-scale network automation, (v) an all-spectrum reconfigurable front-end for dynamic spectrum access, (vi) ambient backscatter communications for energy savings, (vii) the Internet of Space Things enabled by CubeSats and UAVs, and (viii) cell-free massive MIMO communication networks. In this roadmap paper, use cases for these enabling techniques as well as recent advancements on related topics are highlighted, and open problems with possible solutions are discussed, followed by a development timeline outlining the worldwide efforts in the realization of 6G. Going beyond 6G, promising early-stage technologies such as the Internet of NanoThings, the Internet of BioNanoThings, and quantum communications, which are expected to have a far-reaching impact on wireless communications, have also been discussed at length in this paper.

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6G and Beyond: The Future of Wireless Communications Systems

Come with us to read a new book that is coming recently. Yeah, this is a new coming book that many people really want to read will you be one of them? Of course, you should be. It will not make you feel so hard to enjoy your life. Even some people think that reading is a hard to do, you must be sure that you can do it. Hard will be felt when you have no ideas about what kind of book to read. Or sometimes, your reading material is not interesting enough.

Design Of Integrated Circuits For Optical Communications

This expanded and thoroughly revised edition of Thomas H. Lee's acclaimed guide to the design of gigahertz RF integrated circuits features a completely new chapter on the principles of wireless systems. The chapters on low-noise amplifiers, oscillators and phase noise have been significantly expanded as well. The chapter on architectures now contains several examples of complete chip designs that bring together all the various theoretical and practical elements involved in producing a prototype chip. First Edition Hb (1998): 0-521-63061-4 First Edition Pb (1998); 0-521-63922-0

The Design of CMOS Radio-Frequency Integrated Circuits: RF CIRCUITS THROUGH THE AGES

This review of array antennas highlights those elements of theory and hardware that are a part of the present rapid technological growth. The growth and change in array antennas include increased emphasis on "special-purpose" array techniques such as conformal and printed circuit arrays, wide angle scanning arrays, techniques for limited sector coverage, and antennas with dramatically increased pattern control features such as low sidelobe, adaptively controlled patterns. These new topics have substantially replaced large radar arrays in the literature and constitute a major change in the technology. The paper presents a tutorial review of theoretical developments emphasizing techniques appropriate to finite arrays, but indicating parallel developments in infinite array theory, which has become the useful tool for analysis of large arrays. A brief review of the theory of ideal arrays is followed by a generalized formulation of array theory including mutual coupling effects, and is appropriate to finite or infinite arrays of arbitrary wire elements or apertures in the presence of a conducting ground screen. Some results of array tolerance theory are summarized from the literature and retained as reference throughout discussions of array component requirements and device tolerance for low sidelobe arrays. Examples from present technology include conformal and hemispherical coverage arrays, lightweight printed circuit arrays, systems for use with reflectors and lenses in limited sector coverage applications, and wide-band array techniques.

Phased array theory and technology

The synchronization between wireless sensor nodes is a big issue in all those low-cost systems in which each node performs measurements using its own sensors and stores the measured values locally. In the absence of synchronization, it is impossible to relate all the measurements coming from the different sub-systems on a single time scale for the extraction of complex features. The importance of this issue is even bigger when the sensors' sampling rate is high as for the Inertial Measurement Unit platforms. The paper addresses the issue of managing a large multi-sensor platform for off-line activities with a reduced sensor node complexity and guaranteeing the perfect synchronization for each acquired sample. The new simple and light algorithm proposed overcomes the limits of the commonly used protocols and it is suitable for this kind of applications. The entire system consists of an Android smartphone, a master unit and several slave units. Each board has a 9 Degrees of Freedom (DoF) Inertial Measurement Unit, a micro-SD for data storage and an ARM® Cortex ™-M4 CPU SoC supporting the protocols for both Bluetooth Low Energy (BLE) 5 and 2.4 GHz custom communications.

Multiple Synchronized Inertial Measurement Unit Sensor Boards Platform for Activity Monitoring

One of the objectives of the medicine is to modify patients’ ways of living. In this context, a key role is played by the diagnosis. When dealing with acquisition systems consisting of multiple wireless devices located in different parts of the body, it becomes fundamental to ensure synchronization between the individual units. This task is truly a challenge, so one aims to limit the complexity of the calculation and ensure long periods of operation. In fact, in the absence of synchronization, it is impossible to relate all the measurements coming from the different subsystems on a single time scale for the extraction of complex characteristics. In this paper, we first analyze in detail all the possible causes that lead to have a system that is not synchronous and therefore not usable. Then, we propose a firmware implementation strategy and a simple but effective protocol that guarantees perfect synchrony between the devices while keeping computational complexity low. The employed network has a star topology with a master/slave architecture. In this paper a new approach to the synchronization problem is introduced to guarantee a precise but not necessarily accurate synchronization between the units. In order to demonstrate the effectiveness of the proposed solution, a platform consisting of two different types of units has been designed and built. In particular, a nine Degrees of Freedom (DoF) Inertial Measurement Unit (IMU) is used in one unit while a nine-DoF IMU and all circuits for the analysis of the superficial Electromyography (sEMG) are present on the other unit. The system is completed by an Android app that acts as a user interface for starting and stopping the logging operations. The paper experimentally demonstrates that the proposed solution overcomes all the limits set out and it guarantees perfect synchronization of the single measurement, even during long-duration acquisitions. In fact, a less than 30 μ s time mismatch has been registered for a 24 h test, and the possibility to perform complex post-processing on the acquired data with a simple and effective system has been proven.

https://www.mdpi.com/2079-9292/9/7/1118/pdf

A Synchronized Multi-Unit Wireless Platform for Long-Term Activity Monitoring

The main purpose of this paper is to review the framework behind direct digital synthesizer phase-locked loops (DDS-PLLs), as well as to provide a set of novel techniques that can be used during the development and the deployment of phased arrays based on local oscillator (LO) phase shifting approaches. A beam steering transmitter prototype employing our revised DDS-PLL architecture and the experimental results obtained during its characterization are presented. The main contribution of the proposed implementation consists in showing that the output phase increments of the DDS-PLL are unaffected by the frequency multiplication operated by the PLL. The proposed prototype is centered at 3.350 GHz and allows to independently set the phase of its four LOs at 2.453 GHz with an 8-bit resolution. The DDS-PLL architecture is frequency-independent, and the modular structure of its phase control units allows to achieve different phase resolutions with a very small redesign effort.

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DDS-PLL Phase Shifter Architectures for Phased Arrays: Theory and Techniques

This brief introduces a full-hardware approach for Angle of Arrival (AoA) estimation in phased array antennas. The system has a modular structure composed of an analog section to up/down-convert RF signals and a digital section for the AoA estimation. The estimation furnished by the proposed approach can be used to perform adaptive beamforming either to increase the range of operation and/or reduce transmitted power in IoT applications. Some preliminary experimental results are reported validating the proposed strategy for a single narrowband received signal.

Angle of Arrival Estimation Through a Full-Hardware Approach for Adaptive Beamforming

The paper presents a wearable wireless system and a proprietary algorithm along with a preliminary study on the time gait variability analysis as a tool for early diagnosis. The system is non-invasive and it is composed by a set of Inertial Measurements Units (IMUs) positioned on the patient leg. Each unit in the set bases its operations on Bluetooth Low Energy (BLE) standard. Experimental results validating system capabilities are reported and discussed.

Gianfranco Avitabile

Papers

Multiple Synchronized Inertial Measurement Unit Sensor Boards Platform for Activity Monitoring

A Synchronized Multi-Unit Wireless Platform for Long-Term Activity Monitoring

DDS-PLL Phase Shifter Architectures for Phased Arrays: Theory and Techniques

Angle of Arrival Estimation Through a Full-Hardware Approach for Adaptive Beamforming

A wearable wireless system for gait analysis for early diagnosis of Alzheimer and Parkinson disease