Slocalization: Sub-{\mu}W Ultra Wideband Backscatter Localization

Ultra wideband technology has shown great promise for providing high-quality location estimation, even in complex indoor multipath environments, but existing ultra wideband systems require tens to hundreds of milliwatts during operation. Backscatter communication has demonstrated the viability of astonishingly low-power tags, but has thus far been restricted to narrowband systems with low localization resolution. The challenge to combining these complimentary technologies is that they share a compounding limitation, constrained transmit power. Regulations limit ultra wideband transmissions to just -41.3 dBm/MHz, and a backscatter device can only reflect the power it receives. The solution is long-term integration of this limited power, lifting the initially imperceptible signal out of the noise. This integration only works while the target is stationary. However, stationary describes the vast majority of objects, especially lost ones. With this insight, we design Slocalization, a sub-microwatt, decimeter-accurate localization system that opens a new tradeoff space in localization systems and realizes an energy, size, and cost point that invites the localization of every thing. To evaluate this concept, we implement an energy-harvesting Slocalization tag and find that Slocalization can recover ultra wideband backscatter in under fifteen minutes across thirty meters of space and localize tags with a mean 3D Euclidean error of only 30 cm.Comment: Published at the 17th ACM/IEEE Conference on Information Processing in Sensor Networks (IPSN'18

Improving RF Localization Through Measurement and Manipulation of the Channel Impulse Response

For over twenty years, global navigation satellite systems like GPS have provided an invaluable navigation, tracking, and time synchronization service that is used by people, wildlife, and machinery. Unfortunately, the coverage and accuracy of GPS is diminished or lost when brought indoors since GPS signals experience attenuation and distortion after passing through and reflecting off of building materials. This disparity in coverage coupled with growing demands for indoor positioning, navigation, and tracking has led to a plethora of research in localization technologies. To date, however, no single system has emerged as a clear solution to the indoor localization and navigation problem because the myriad of potential applications have widely varying performance requirements and design constraints that no system satisfies. Fortunately, recently-introduced commercial ultra-wideband RF hardware offers excellent ranging accuracy in difficult indoor settings, but these systems lack the robustness and simplicity needed for many indoor applications. We claim that an asymmetric design that separates transmit and receive functions can enable many of the envisioned applications not currently realizable with an integrated design. This separation of functionality allows for a flexible architecture which is more robust to the in-band interference and heavy multipath commonly found in indoor environments. In this dissertation, we explore the size, weight, accuracy, and power requirements imposed on tracked objects (tags) for three broadly representative applications and propose the design of fixed-location infrastructure (anchors) that accurately and robustly estimate a tag’s location, while minimizing deployment complexity and adhering to a unified system architecture. Enabled applications range from 3D tracking of small, fast-moving micro-quadrotors to 2D personal navigation across indoor maps to tracking objects that remain stationary for long periods of time with near-zero energy cost. Each application requires careful measurement of the ultra-wideband channel impulse response, and an augmented narrowband receiver is proposed to perform these measurements. The key design principle is to offload implementation complexity to static infrastructure where an increase in cost and complexity can be more easily absorbed and amortized. Finally, with an eye towards the future, we explore how the increasingly crowded RF spectrum impacts current ultra-wideband system design, and propose an alternative architecture that enables improved coexistence of narrowband and ultra-wideband transmissions.PHDComputer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/138642/1/bpkempke_1.pd

Real-Time Waveform Prototyping

Mobile Netzwerke der fünften Generation zeichen sich aus durch vielfältigen Anforderungen und Einsatzszenarien. Drei unterschiedliche Anwendungsfälle sind hierbei besonders relevant: 1) Industrie-Applikationen fordern Echtzeitfunkübertragungen mit besonders niedrigen Ausfallraten. 2) Internet-of-things-Anwendungen erfordern die Anbindung einer Vielzahl von verteilten Sensoren. 3) Die Datenraten für Anwendung wie z.B. der Übermittlung von Videoinhalten sind massiv gestiegen. Diese zum Teil gegensätzlichen Erwartungen veranlassen Forscher und Ingenieure dazu, neue Konzepte und Technologien für zukünftige drahtlose Kommunikationssysteme in Betracht zu ziehen. Ziel ist es, aus einer Vielzahl neuer Ideen vielversprechende Kandidatentechnologien zu identifizieren und zu entscheiden, welche für die Umsetzung in zukünftige Produkte geeignet sind. Die Herausforderungen, diese Anforderungen zu erreichen, liegen jedoch jenseits der Möglichkeiten, die eine einzelne Verarbeitungsschicht in einem drahtlosen Netzwerk bieten kann. Daher müssen mehrere Forschungsbereiche Forschungsideen gemeinsam nutzen. Diese Arbeit beschreibt daher eine Plattform als Basis für zukünftige experimentelle Erforschung von drahtlosen Netzwerken unter reellen Bedingungen. Es werden folgende drei Aspekte näher vorgestellt: Zunächst erfolgt ein Überblick über moderne Prototypen und Testbed-Lösungen, die auf großes Interesse, Nachfrage, aber auch Förderungsmöglichkeiten stoßen. Allerdings ist der Entwicklungsaufwand nicht unerheblich und richtet sich stark nach den gewählten Eigenschaften der Plattform. Der Auswahlprozess ist jedoch aufgrund der Menge der verfügbaren Optionen und ihrer jeweiligen (versteckten) Implikationen komplex. Daher wird ein Leitfaden anhand verschiedener Beispiele vorgestellt, mit dem Ziel Erwartungen im Vergleich zu den für den Prototyp erforderlichen Aufwänden zu bewerten. Zweitens wird ein flexibler, aber echtzeitfähiger Signalprozessor eingeführt, der auf einer software-programmierbaren Funkplattform läuft. Der Prozessor ermöglicht die Rekonfiguration wichtiger Parameter der physikalischen Schicht während der Laufzeit, um eine Vielzahl moderner Wellenformen zu erzeugen. Es werden vier Parametereinstellungen 'LLC', 'WiFi', 'eMBB' und 'IoT' vorgestellt, um die Anforderungen der verschiedenen drahtlosen Anwendungen widerzuspiegeln. Diese werden dann zur Evaluierung der die in dieser Arbeit vorgestellte Implementierung herangezogen. Drittens wird durch die Einführung einer generischen Testinfrastruktur die Einbeziehung externer Partner aus der Ferne ermöglicht. Das Testfeld kann hier für verschiedenste Experimente flexibel auf die Anforderungen drahtloser Technologien zugeschnitten werden. Mit Hilfe der Testinfrastruktur wird die Leistung des vorgestellten Transceivers hinsichtlich Latenz, erreichbarem Durchsatz und Paketfehlerraten bewertet. Die öffentliche Demonstration eines taktilen Internet-Prototypen, unter Verwendung von Roboterarmen in einer Mehrbenutzerumgebung, konnte erfolgreich durchgeführt und bei mehreren Gelegenheiten präsentiert werden.:List of figures List of tables Abbreviations Notations 1 Introduction 1.1 Wireless applications 1.2 Motivation 1.3 Software-Defined Radio 1.4 State of the art 1.5 Testbed 1.6 Summary 2 Background 2.1 System Model 2.2 PHY Layer Structure 2.3 Generalized Frequency Division Multiplexing 2.4 Wireless Standards 2.4.1 IEEE 802.15.4 2.4.2 802.11 WLAN 2.4.3 LTE 2.4.4 Low Latency Industrial Wireless Communications 2.4.5 Summary 3 Wireless Prototyping 3.1 Testbed Examples 3.1.1 PHY - focused Testbeds 3.1.2 MAC - focused Testbeds 3.1.3 Network - focused testbeds 3.1.4 Generic testbeds 3.2 Considerations 3.3 Use cases and Scenarios 3.4 Requirements 3.5 Methodology 3.6 Hardware Platform 3.6.1 Host 3.6.2 FPGA 3.6.3 Hybrid 3.6.4 ASIC 3.7 Software Platform 3.7.1 Testbed Management Frameworks 3.7.2 Development Frameworks 3.7.3 Software Implementations 3.8 Deployment 3.9 Discussion 3.10 Conclusion 4 Flexible Transceiver 4.1 Signal Processing Modules 4.1.1 MAC interface 4.1.2 Encoding and Mapping 4.1.3 Modem 4.1.4 Post modem processing 4.1.5 Synchronization 4.1.6 Channel Estimation and Equalization 4.1.7 Demapping 4.1.8 Flexible Configuration 4.2 Analysis 4.2.1 Numerical Precision 4.2.2 Spectral analysis 4.2.3 Latency 4.2.4 Resource Consumption 4.3 Discussion 4.3.1 Extension to MIMO 4.4 Summary 5 Testbed 5.1 Infrastructure 5.2 Automation 5.3 Software Defined Radio Platform 5.4 Radio Frequency Front-end 5.4.1 Sub 6 GHz front-end 5.4.2 26 GHz mmWave front-end 5.5 Performance evaluation 5.6 Summary 6 Experiments 6.1 Single Link 6.1.1 Infrastructure 6.1.2 Single Link Experiments 6.1.3 End-to-End 6.2 Multi-User 6.3 26 GHz mmWave experimentation 6.4 Summary 7 Key lessons 7.1 Limitations Experienced During Development 7.2 Prototyping Future 7.3 Open points 7.4 Workflow 7.5 Summary 8 Conclusions 8.1 Future Work 8.1.1 Prototyping Workflow 8.1.2 Flexible Transceiver Core 8.1.3 Experimental Data-sets 8.1.4 Evolved Access Point Prototype For Industrial Networks 8.1.5 Testbed Standardization A Additional Resources A.1 Fourier Transform Blocks A.2 Resource Consumption A.3 Channel Sounding using Chirp sequences A.3.1 SNR Estimation A.3.2 Channel Estimation A.4 Hardware part listThe demand to achieve higher data rates for the Enhanced Mobile Broadband scenario and novel fifth generation use cases like Ultra-Reliable Low-Latency and Massive Machine-type Communications drive researchers and engineers to consider new concepts and technologies for future wireless communication systems. The goal is to identify promising candidate technologies among a vast number of new ideas and to decide, which are suitable for implementation in future products. However, the challenges to achieve those demands are beyond the capabilities a single processing layer in a wireless network can offer. Therefore, several research domains have to collaboratively exploit research ideas. This thesis presents a platform to provide a base for future applied research on wireless networks. Firstly, by giving an overview of state-of-the-art prototypes and testbed solutions. Secondly by introducing a flexible, yet real-time physical layer signal processor running on a software defined radio platform. The processor enables reconfiguring important parameters of the physical layer during run-time in order to create a multitude of modern waveforms. Thirdly, by introducing a generic test infrastructure, which can be tailored to prototype diverse wireless technology and which is remotely accessible in order to invite new ideas by third parties. Using the test infrastructure, the performance of the flexible transceiver is evaluated regarding latency, achievable throughput and packet error rates.:List of figures List of tables Abbreviations Notations 1 Introduction 1.1 Wireless applications 1.2 Motivation 1.3 Software-Defined Radio 1.4 State of the art 1.5 Testbed 1.6 Summary 2 Background 2.1 System Model 2.2 PHY Layer Structure 2.3 Generalized Frequency Division Multiplexing 2.4 Wireless Standards 2.4.1 IEEE 802.15.4 2.4.2 802.11 WLAN 2.4.3 LTE 2.4.4 Low Latency Industrial Wireless Communications 2.4.5 Summary 3 Wireless Prototyping 3.1 Testbed Examples 3.1.1 PHY - focused Testbeds 3.1.2 MAC - focused Testbeds 3.1.3 Network - focused testbeds 3.1.4 Generic testbeds 3.2 Considerations 3.3 Use cases and Scenarios 3.4 Requirements 3.5 Methodology 3.6 Hardware Platform 3.6.1 Host 3.6.2 FPGA 3.6.3 Hybrid 3.6.4 ASIC 3.7 Software Platform 3.7.1 Testbed Management Frameworks 3.7.2 Development Frameworks 3.7.3 Software Implementations 3.8 Deployment 3.9 Discussion 3.10 Conclusion 4 Flexible Transceiver 4.1 Signal Processing Modules 4.1.1 MAC interface 4.1.2 Encoding and Mapping 4.1.3 Modem 4.1.4 Post modem processing 4.1.5 Synchronization 4.1.6 Channel Estimation and Equalization 4.1.7 Demapping 4.1.8 Flexible Configuration 4.2 Analysis 4.2.1 Numerical Precision 4.2.2 Spectral analysis 4.2.3 Latency 4.2.4 Resource Consumption 4.3 Discussion 4.3.1 Extension to MIMO 4.4 Summary 5 Testbed 5.1 Infrastructure 5.2 Automation 5.3 Software Defined Radio Platform 5.4 Radio Frequency Front-end 5.4.1 Sub 6 GHz front-end 5.4.2 26 GHz mmWave front-end 5.5 Performance evaluation 5.6 Summary 6 Experiments 6.1 Single Link 6.1.1 Infrastructure 6.1.2 Single Link Experiments 6.1.3 End-to-End 6.2 Multi-User 6.3 26 GHz mmWave experimentation 6.4 Summary 7 Key lessons 7.1 Limitations Experienced During Development 7.2 Prototyping Future 7.3 Open points 7.4 Workflow 7.5 Summary 8 Conclusions 8.1 Future Work 8.1.1 Prototyping Workflow 8.1.2 Flexible Transceiver Core 8.1.3 Experimental Data-sets 8.1.4 Evolved Access Point Prototype For Industrial Networks 8.1.5 Testbed Standardization A Additional Resources A.1 Fourier Transform Blocks A.2 Resource Consumption A.3 Channel Sounding using Chirp sequences A.3.1 SNR Estimation A.3.2 Channel Estimation A.4 Hardware part lis

High-Performance Reconfigurable Piezoelectric Resonators and Filters for RF Frontend Applications

A conventional RF frontend module consists of many filters where each filter is allocated for a specific frequency band. These filters are connected through multiplexing switch networks to support multi-band wireless standards. Using an individual filter for each frequency band increases the module size, power consumption and cost. Therefore, implementation of reconfigurable filters that can operate at different frequency bands while maintaining key RF performance requirements such as low insertion loss, good linearity and power handling is necessary for manufacturing of future RF frontends. Acoustic wave resonators based on piezoelectric devices such as Surface Acoustic Wave (SAW) and Bulk Acoustic Wave (BAW) are the most commonly used technologies to manufacture filters for RF applications. The objective of the research described in this thesis is to investigate the feasibility of tunable filter solutions using piezoelectric SAW resonators. A tunable SAW technology which can maintain required performance parameters and can be commercially manufactured will constitute a technological breakthrough in wireless communications. Thin-Film Piezoelectric on Substrate (TPoS) resonators, based on Aluminum Nitride (AlN) piezoelectric material which are fabricated using commercially available Silicon on Insulator (SOI) PiezoMUMPs process, have been demonstrated. By combining the superior acoustic properties of AlN and single crystalline silicon substrate, this class of resonators achieves ultra-high quality factor (Q) values in excess of 3600. A 3-pole bandpass filter using direct electrical coupling between the resonators has been presented and we have studied the performance of the fabricated filter over a temperature range from -196ºC up to +120ºC and under high power. For the first time, we have demonstrated the integration of switching elements, based on Vanadium Dioxide (VO2) phase change material, with Incredible-High-Performance SAW (IHP-SAW) technology which allows us to design and implement switchable and reconfigurable SAW resonators and filters for wireless applications. Switchable multi-band filters using VO2 switches strategically imbedded within the resonators of the filter have been demonstrated. A switchable dual-band filter with four switching states and two channels was presented using hybrid integration approach where discrete VO2 switches were fabricated separately and then integrated with the SAW resonators and filters using wire bonds. The fabricated 5-pole dual-band filter demonstrated good insertion loss in both transmission states but had inadequate performance in terms of isolation between the channels due to the limitations of the hybrid integration approach. Moreover, hybrid integration does not allow us to use more than a few switching elements and cannot be used for the implementation of higher order filters. To address these issues, we have demonstrated the monolithic integration of VO2 switches using an in-house fabrication process that allows us to fabricate VO2 switches and SAW resonators and filters on a single chip. A dual-band switchable higher order 7-pole filter with six monolithically integrated VO2 switches, three for each channel, was demonstrated. The monolithic integration allows the single-chip implementation of the proposed switchable dual-band filter with improved performance along with significant size reduction and ease of manufacturing, paving the path for commercialization of this technology. Novel reconfigurable SAW resonators and filters with tunable center frequency were also presented for the first time. Tuning of the center frequency between two different states was achieved by changing the configuration of interdigitated electrodes within the SAW resonator and by using a set of tuning electrodes and VO2 switches. In the first implementation, the VO2 switches were integrated over the electrodes and inside the active area of the SAW resonator. Each resonator consists of hundreds of tuning electrodes and for a reliable switching each resonator requires a number of heater elements which results in increased DC power consumption and total size. A second reconfigurable resonator with a modified structure and using a modified in-house fabrication process to include a second electrode layer was proposed to reduce the number of required VO2 switching elements for an even more compact implementation and ten times reduction in the required DC power consumption. Design, implementation, and measurement results for a 3-pole tunable SAW filter based on the proposed reconfigurable resonators have been presented. The filter’s center frequency is tuned from 733 MHz to 713 MHz while the insertion loss was maintained below 2.5 dB. The fabricated SAW resonators and filters also showed acceptable linear and high-power performance characteristics. This is the first time a single-chip implementation of a reconfigurable SAW filter with center frequency tuning and acceptable RF performance using monolithically integrated VO2 switches is ever reported. The single-chip implementation of the proposed SAW resonators and filters enables the development of future low-cost RF multi-band transceivers with improved performance and functionality

Real100G.COM

In 2012 a group of researchers proposed a basic research initiative to the German Research Foundation (DFG) as a special priority project (SPP) with the name: Wireless 100 Gbps and beyond. The main goal of this initiative was the investigation of architectures, technologies and methods to go well beyond the state of the art. The target of 100 Gbps was set far away from the (at that time) achievable 1 Gbps such that it was not possible to achieve promising results just by tuning some parameters. We wanted to find breakthrough solutions. When we started the work on the proposal we discussed the challenges to be addressed in order to advancing the wireless communication speed significantly. Having the fundamental Shannon boundary in mind we discussed how to achieve the 100 Gbps speed.Angesichts der rapiden Entwicklung der Funkkommunikation hat die Deutsche Forschungsgemeinschaft im Jahr 2012 ein Schwerpunktprogramm mit dem Titel "Wireless 100 Gbps and beyound" (dt.: Drahtloskommunikation mit 100 Gbps und mehr) gestartet. Diese Initiative zielte auf neue Lösungen, Methoden und neues Wissen zur Lösung des Problems des kontinuierlichen Bedarfs an immer höheren Datenraten im Bereich der Funkkommunikation. Eine international besetze Jury hat etliche Projektvorschläge evaluiert, aus denen 11 Projekte ausgewählt und über zweimal 3 Jahre von Mitte 2013 bis Mitte 2019 gefördert wurden. Das vorliegende Buch versammelt die Ansätze, Architekturen und Erkenntnisse der Projekte. Es überspannt einen breiten Themenbereich, angefangen mit speziellen Fragen der physikalischen Übertragung, des Antennendesigns und der HF-Eingangs-Architekturen für unterschiedliche Frequenzbereiche bis 240 GHz. Darüber hinaus beschreibt das Buch Ansätze für Ultra-Hochgeschwindigkeits-Funksysteme, deren Basisbandverarbeitung, Kodierung sowie mögliche Umsetzungen. Nicht zuletzt wurden auch Fragen des Protokolldesigns behandelt, um eine enge Integration in moderne Computersysteme zu erleichtern

Passive und aktive Radio Frequency Identification Tags im 60-GHz-Band

Die Einführung des millimeter-Wellen-Bandes eröffnet neue Perspektiven für die Radio Frequency Identification (RFID) Kommunikationssysteme. Der Enwurf des Systems im 60-GHz-Band ermöglicht die Implementierung der On-Chip Antenne und darüber hinaus die Implementierung eines RFID-Tags auf einem einzigen Chip. Dennoch ist es aufgrund der gesetzlichen Beschränkung der effektiven isotropen Strahlungsleistung (EIRP) des Lesegeräts und der erhöhten Freiraum-Dielektrikumsverluste eine Herausforderung, eine zuverlässige Kommunikationsreichweite von mehreren Millimetern zu erreichen. Neue Lösungen sind für jeden Block sowohl im Lesegerät als auch im Single-Chip-Tag erforderlich. Obwohl das Lesegerät batteriebetrieben ist, ist es immer noch eine Herausforderung, die maximal zulässigen 20 dBm IERP des Lesersenders energieeffizient zu erzeugen. Darüber hinaus sollte der Empfänger einen ausreichenden Dynamikbereich haben, um das vom Tag kommende Signal zu erkennen. Auf der Tag-Seite sind die Hauptherausforderungen das Co-Design der effizienten On-Chip-Antennen-Implementierung, die hochempfindliche Gleichrichter-Implementierung und das Rückkommunikationskonzept. Diese Arbeit konzentriert sich auf die Machbarkeitsstudie des Single-Chip-RFID-Tags und die Implementierung im Millimeterwellenbereich. Es werden zwei Rückkommunikationskonzepte untersucht - Backscattering-Rückkommunikation und eine Kommunikation unter Verwendung von Ultra-Low-Power (ULP) Radios. Beide werden in einem 22 nm FDSOI Prozess auf einem Substrat mit geringem Widerstand implementiert. Beide Tags arbeiten mit einer Versorgungsspannung von 0,4 V, um die Kommunikationsreichweite zu maximieren. Die Link-Budgets sind so ausgelegt, dass sie die regulatorischen Beschränkungen einhalten. Die Auswahl des Technologieknotens wird begründet. Verschiedene Aspekte im Zusammenhang mit der Technologie werden diskutiert, wie z. B. Geräteleistung, passiver Qualitätsfaktor, Leistungsdichte der Kondensatoren. Der Backscattering RFID-Tag wird zuerst entworfen, da er eine relativ einfachere Topologie hat. Die Probleme der Gleichrichterempfindlichkeit im Rahmen des analogen Frontends, der On-Chip-Antenneneffizienz und der konjugierten Anpassung beider werden untersucht. Eine Kommunikationsreichweite von 5 mm wird angestrebt und realisiert. Um die Kommunikationsreichweite weiter zu erhöhen, wird in der zweiten Phase ein Tag mit einer aktiven Rückkommunikation implementiert. Hier wird die Gleichrichterempfindlichkeit weiter verbessert. Es wird ein 0,4V ULP Radio entworfen, das sich die Antenne mit dem Gleichrichter über einen Single-Pole- Double-Through (SPDT) Schalter teilt. Ein Abstand von 2 cm erwies sich als realisierbar, wobei die gesetzlichen Bestimmungen eingehalten und der dynamische Bereich des Leseempfängers nicht überschritten wurde. Es wird die höchste normalisierte Kommunikationsreichweite pro Leser-EIRP erreicht. Weitere Verbesserungsmöglichkeiten werden diskutiert

An ultra low voltage micropower GPS receiver RF front-end for wildlife tracking

A fully integrated CMOS GPS receiver RF front end optimized for low power operation is presented. The system operates with a supply voltage down to 250 mV. A prototype has been fabricated in a 0.13μm CMOS process and includes a low voltage LNA, quadrature oscillators, and quadrature mixers. It exhibits an order of magnitude lower power consumption than the best previously published work. The system has a measured gain of 42 dB, a noise figure of 8.6 dB, and an oscillator phase noise of -113.8 dBc/Hz at a 1 MHz offset while consuming a maximum of 580 μW of power and requiring no external components