150 research outputs found
Signal Design and Machine Learning Assisted Nonlinearity Compensation for Coherent Optical Fibre Communication Links
This thesis investigates low-complexity digital signal processing (DSP) for signal design and nonlinearity compensation strategies to improve the performance of single-mode optical fibre links over different distance scales.
The performance of a novel ML-assisted inverse regular perturbation technique that mitigates fibre nonlinearities was investigated numerically with a dual-polarization 64 quadrature amplitude modulation (QAM) link over 800 km distance. The model outperformed the heuristically-optimised digital backpropagation approach with <5 steps per span and mitigated the gain expansion issue, which limits the accuracy of an untrained model when the balance between the nonlinear and linear components becomes considerable.
For short reach links, the phase noise due to low-cost, high-linewidth lasers is a more significant channel impairment. A novel constellation optimisation algorithm was, therefore, proposed to design modulation formats that are robust against both additive white Gaussian noise (AWGN) and the residual laser phase noise (i.e., after carrier phase estimation). Subsequently, these constellations were numerically validated in the context of a 400ZR standard system, and achieved up to 1.2 dB gains in comparison with the modulation formats which were optimised only for the AWGN channel.
The thesis concludes by examining a joint strategy to modulate and demodulate signals in a partially-coherent AWGN (PCAWGN) channel. With a low-complexity PCAWGN demapper, 8- to 64-ary modulation formats were designed and validated through numerical simulations. The bit-wise achievable information rates (AIR) and post forward error correction (FEC) bit error rates (BER) of the designed constellations were numerically validated with: the theoretically optimum, Euclidean (conventional), and low-complexity PCAWGN demappers. The resulting constellations demonstrated post-FEC BER shaping gains of up to 2.59 dB and 2.19 dB versus uniform
64 QAM and 64-ary constellations shaped for the purely AWGN channel model, respectively.
The described geometric shaping strategies can be used to either relax linewidth and/or carrier phase estimator requirements, or to increase signal-to-noise ratio (SNR) tolerance of a system in the presence of residual phase noise
Methods for Improving Performance in Consumer Grade GNSS Receivers
Viimeisten kolmen vuosikymmenen aikana satelliittinavigointi on kehittynyt ammatti ja sotilaskäyttäjien tekniikasta kaikkien saatavilla olevaksi tekniikaksi. Varsinkin viimeisen 15 vuoden aikana, kun vastaanottimet alkoivat pienentyä ja halpenivat, on lisääntynyt määrä yrityksiä, jotka toimittavat GPS-laitteita satoihin erilaisiin sovelluksiin. Kaikille moderneille tekniikoille on myös tyypillistä, että tutkimukseen ja siihen liittyvään vastaanottimien kehittämiseen on käytetty valtavasti rahaa, mikä on johtanut huomattavaan parantumiseen vastaanottimen suorituskyvyssä.
GPS-vastaanottimien kehitystyön lisäksi uusien maailmanlaajuisten satelliittinavigointijärjestelmien, kuten venäläisen GLONASS, kiinalaisen BeiDou- ja eurooppalaisen Galileo-järjestelmien käyttöönotto tarjoaa entistä enemmän mahdollisuuksia suorituskyvyn parantamiseen. Sekä GPS että nämä uudet järjestelmät ovat myös ottaneet käyttöön uudentyyppisiä signaalirakenteita, jotka voivat tarjota parempilaatuisia havaintoja ja siten parantaa kaikkien vastaanottimien suorituskykyä.
Lopuksi menetelmät, kuten PPP ja RTK, jotka aiemmin olivat varattu ammattikäyttäjille, ovat tulleet kuluttajamarkkinoille mahdollistaen ennennäkemättömän suorituskyvyn jokaiselle satelliittinavigointivastaanottimien käyttäjälle.
Tässä opinnäytetyössä arvioidaan tämän kehityksen vaikutusta sekä suorituskykyyn että vastaanottimen arkkitehtuuriin.
Työssä esitellään yksityiskohtaisesti FGI:ssä kehitetyn ohjelmistopohjaisen vastaanottimen, FGI-GSRx:n. Tämän vastaanottimen avulla on työssä arvioitu miten sekä uudet konstellaatiot että uudet nykyaikaiset signaalit ja niitten seurantamenetelmät vaikuttavat suorituskykyyn ja vastaanotin arkkitehtuuriin. Tämän lisäksi on arvioitu PPP- ja RTK-tarkkuuspaikannusmenetelmien vaikutus FinnRefCORS-verkkoa käyttäen useiden erityyppisten vastaanottimien kanssa, mukaan lukien kuluttajalaatuiset vastaanottimet.
Tulokset osoittavat, että enemmän konstellaatioita ja signaaleja käytettäessä paikannusratkaisun tarkkuus paranee 3 metristä 1,4 metriin hyvissä olosuhteissa ja yli 10-kertaiseksi tiheästi rakennetuissa kaupungeissa, jossa käytettävissä olevien signaalien määrä kasvaa kertoimella 2 käytettäessä kolmea konstellaatiota. Uusia moderneja modulaatiotekniikoita, kuten BOC-modulaatiota, käytettäessä tulokset osoittavat Galileo-ratkaisun tarkkuuden paranevan lähes 25%:lla ja esitelty uusi signaalinkäsittelymenetelmä lisää tällaisen tarkkuuden saatavuutta 50%:sta lähes 100%:iin. Lopuksi tarkkuuspaikannusmenetelmien tulokset osoittavat, että 15 cm:n tarkkuus on saavutettavissa, mikä on merkittävä parannus verrattuna 1,4 metrin tarkkuuteen.
Näiden parannusten saavuttamiseksi on olennaista, että itse vastaanotin on mukautettu hyödyntämään näitä uusia signaaleja ja konstellaatioita. Tämä tarkoittaa, että nykyaikaisten kuluttajamarkkinoiden vastaanottimien suunnittelu on haastavaa ja monissa tapauksissa ohjelmistopohjainen vastaanotin olisi parempi ja halvempi valinta kuin uusien mikropiirien kehittäminen.For the last three decades, satellite navigation has evolved from being a technology for professional and military users to a technology available for everyone. Especially during the last 15 years, since the receivers started getting smaller and cheaper, there has been an increasing number of companies delivering Global Positioning System (GPS) enabled devices for hundreds of different kind of applications. Typical for any modern technology, there has also been an enormous amount of money spent on research and accompanied receiver development resulting in an immense increase
in receiver performance.
In addition to the development efforts on GPS receivers the introduction of new global navigation satellite systems such as the Russian Globalnaja Navigatsionnaja Sputnikovaja Sistema (GLONASS), the Chinese BeiDou, and the European Galileo systems offers even more opportunities for improved performance. Both GPS and these new systems have also introduced new types of signal structures that can provide better quality observations and even further improve the performance of all receivers.
Finally, methods like Precise Point Positioning (PPP) and Real Time Kinematic (RTK) that earlier were reserved for professional users have entered into the consumer market enabling never before seen performance for every user of satellite navigation receivers.
This thesis will assess the impact of this development on both performance as well as on receiver architecture.
The design of the software defined receiver developed at FGI, the FGI-GSRx, is presented in detail in this thesis. This receiver has then been used to assess the impact of using multiple constellations as well as new novel signal processing methods for modern signals. To evaluate the impact of PPP and RTK methods the FinnRef Continuously Operating Reference Station (CORS) network has been used together with several different types of receivers including consumer grade off the shelf receivers.
The results show that when using more constellations and signals the accuracy of the positioning solution improves from3 meters to 1.4 meters in open sky conditions and by more than a factor 10 in severe urban canyons. For severe urban canyons the available also increases by a factor 2 when using three constellations. When using new modern modulation techniques like high order BOC results show an accuracy improvement for a Galileo solution of almost 25 % and the presented new signal processing method increase the availability of such an accuracy from 50 % to almost 100 %. Finally, results from precise point positioning methods show that an accuracy of 15 cm is achievable, which is a significant improvement compared to an accuracy of 1.4 m for a standalone multi constellation solution.
To achieve these improvements, it is essential that the receiver itself is adapted to make use of these new signals and constellations. This means that the design of modern consumer market receivers is challenging and in many cases a software define receiver would be a better and cheaper choice than developing new Application Specific Integrated Circuit (ASIC)’s
Computer Aided Verification
This open access two-volume set LNCS 13371 and 13372 constitutes the refereed proceedings of the 34rd International Conference on Computer Aided Verification, CAV 2022, which was held in Haifa, Israel, in August 2022. The 40 full papers presented together with 9 tool papers and 2 case studies were carefully reviewed and selected from 209 submissions. The papers were organized in the following topical sections: Part I: Invited papers; formal methods for probabilistic programs; formal methods for neural networks; software Verification and model checking; hyperproperties and security; formal methods for hardware, cyber-physical, and hybrid systems. Part II: Probabilistic techniques; automata and logic; deductive verification and decision procedures; machine learning; synthesis and concurrency. This is an open access book
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
Design of High Throughput Reconfigurable LDPC CODEC
Channel coding is an essential part of communication systems, which significantly reduces the error rate of receiving messages. Nowadays, iterative decoding methods play an important role in wireless communication such as 5G, Wi-Fi etc. Low-Density Parity-Check (LDPC) codes are one of the most used iterative decoding codes, which attract lots of interest in a wide range of applications. LDPC codes have a channel approaching capacity, which is practical for implementation as well. The thesis focuses on the design of high throughput reconfigurable LDPC channel codec with good performance.
The main focus of this thesis is the design of a novel decoding algorithm for LDPC codes. The new decoding algorithm is configurable to adjust its performance and complexity, which is very flexible for applications. Its error correction capability is close to the sum-product algorithm but with significantly lower complexity. We further implement the LDPC encoder/decoder on FPGA, which is reconfigurable for 5G NR or user-defined LDPC codes. In particular, we apply the new decoding algorithm to the decoder and analyse its performance on hardware.
Moreover, we compared the error detection performance of 5G NR CRC and LDPC Syndrome to investigate the necessity of using CRC decoding or LDPC syndrome check, or both in practical systems. At last, a 5G NR physical layer simulating SoC embedded system is built on FPGA for the verification of the encoder and decoder
Proceedings of the 19th Sound and Music Computing Conference
Proceedings of the 19th Sound and Music Computing Conference - June 5-12, 2022 - Saint-Étienne (France).
https://smc22.grame.f
Advanced Applications of Rapid Prototyping Technology in Modern Engineering
Rapid prototyping (RP) technology has been widely known and appreciated due to its flexible and customized manufacturing capabilities. The widely studied RP techniques include stereolithography apparatus (SLA), selective laser sintering (SLS), three-dimensional printing (3DP), fused deposition modeling (FDM), 3D plotting, solid ground curing (SGC), multiphase jet solidification (MJS), laminated object manufacturing (LOM). Different techniques are associated with different materials and/or processing principles and thus are devoted to specific applications. RP technology has no longer been only for prototype building rather has been extended for real industrial manufacturing solutions. Today, the RP technology has contributed to almost all engineering areas that include mechanical, materials, industrial, aerospace, electrical and most recently biomedical engineering. This book aims to present the advanced development of RP technologies in various engineering areas as the solutions to the real world engineering problems
Recent Advances in Wireless Communications and Networks
This book focuses on the current hottest issues from the lowest layers to the upper layers of wireless communication networks and provides "real-time" research progress on these issues. The authors have made every effort to systematically organize the information on these topics to make it easily accessible to readers of any level. This book also maintains the balance between current research results and their theoretical support. In this book, a variety of novel techniques in wireless communications and networks are investigated. The authors attempt to present these topics in detail. Insightful and reader-friendly descriptions are presented to nourish readers of any level, from practicing and knowledgeable communication engineers to beginning or professional researchers. All interested readers can easily find noteworthy materials in much greater detail than in previous publications and in the references cited in these chapters
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