7 research outputs found
Desenho da camada DLL para sistemas de comunicação por luz visível
Mestrado em Engenharia Electrónica e TelecomunicaçõesWith the advent of the Information Age, communication systems have become
the backbone of our society. The modern society strives to nd instant
access to speci c sources of information to make time-constrained decisions.
Therefore, the twenty- rst century is marked by a growing demand for bandwidth
in wireless communications, as it allows users to communicate and
access daily applications even from remote areas. Up to the present time,
numerous breakthroughs in wireless communications were accomplished but
mainly using the radio portion of the electromagnetic spectrum, which made
RF to take the central role in today's communication systems. However, RF
technology is a victim of its own success. Due to the tremendous increase
in the number of mobile devices, RF technology cannot cope much longer
with this market demand and will eventually reach a saturation point.
VLC is a recently appealing technique in the eld of wireless communications
that intends to complement RF technologies and is sought by many researchers
as a viable alternative. VLC based on Light Emitting Diode (LED)
takes advantage of these solid-state devices superior modulation capability
to transmit data while assuring their lighting functionality. This work addresses
the problem of achieving high bandwidth in a DLL design for OFDM
based VLC broadcast systems and is inserted in a funded project called VLCLighting.
The main objective of this dissertation work is to implement
an e cient DLL in a Microblaze soft processor in a FPGA and to study
its usage in a broadcast VLC system for lighting systems. Since two value
added services were identi ed in the VLCLighting project, the proposed DLL
aims at furnishing the adequate means to fragment and route those services
requests while maintaining a continuous transmission
ow that assures lighting
and transceiver functionality. This work proposes a DLL design that was
inspired in DVB and project OMEGA systems, able to describe the required
amendments to full ll VLCLighting goals.Com a chegada da era da Informação, os sistemas de comunicação
tornaram-se na espinha dorsal da nossa sociedade. A Sociedade Moderna
esforça-se por ter acesso instantâneo a fontes de informação específicas para
tomar decisões limitadas pelo tempo. Portanto, o século XXI está marcado
pela crescente exigência da largura de banda nas comunicações sem fios,
pois tal permite aos utilizadores comunicarem e acederem as aplicações a
partir de áreas longínquas. Até ao momento, foram alcançados diversos
avanços/descobertas na largura de banda das comunicações sem fos, mas
tal tem sido conseguido usando o intervalo de radiofrequências (RF) do espectro
eletromagnético e que fez com que o RF ficasse com o papel principal
nos sistemas de comunicação de hoje. Contudo, a Tecnologia RF e vitima
do seu próprio sucesso. Devido ao tremendo aumento do número de aparelhos
de comunicação móveis, a tecnologia RF não pode lidar muito mais
tempo com a exigência dos mercados e atingirá o seu ponto de saturação.
VLC (Comunicação através de luz visivel) é uma tecnica recente muito apelativa
no campo das comunicações sem-fios e que pretende ser um complemento
à tecnologia RF, sendo considerada por muitos investigadores como
uma alternativa viável. Esta dissertação discute o problema de se alcançar
uma grande taxa de transmissão com a implementação de uma Data Link
Layer (DLL) direccionada para sistemas VLC com modulação OFDM e está
inserida num projecto financiado intitulado VLCLighting. O objectivo principal
desta dissertação consiste na implementação de um DLL eficiente num
processador Microblaze numa Field-Programmable Gate Array (FPGA) e no
estudo da sua utilização em sistemas VLC para uso combinado em sistemas
de iluminação. Uma vez que foram identificados dois serviços com valor acrescentado
para serem incluídos no projecto VLCLighting, a proposta DLL
pretende fornecer os meios necessários á fragmentação e encaminhamento
das exigências dos serviços, enquanto se mantêm um
fluxo contínuo de
transmissão capaz de assegurar as funcionalidades de iluminação e comunicação. A presente dissertação propõe um desenho inspirado nos sistemas
DVB e do projeto OMEGA, e descrevendo as alterações exigidas para satisfazer
os objectivos do projecto VLCLighting
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
Optical Communication
Optical communication is very much useful in telecommunication systems, data processing and networking. It consists of a transmitter that encodes a message into an optical signal, a channel that carries the signal to its desired destination, and a receiver that reproduces the message from the received optical signal. It presents up to date results on communication systems, along with the explanations of their relevance, from leading researchers in this field. The chapters cover general concepts of optical communication, components, systems, networks, signal processing and MIMO systems. In recent years, optical components and other enhanced signal processing functions are also considered in depth for optical communications systems. The researcher has also concentrated on optical devices, networking, signal processing, and MIMO systems and other enhanced functions for optical communication. This book is targeted at research, development and design engineers from the teams in manufacturing industry, academia and telecommunication industries
Infrared ranging in multipath environments for indoor localization of mobile targets
Esta tesis aborda el problema de la medida de diferencias de distancia mediante señales ópticas afectadas por multicamino, aplicada a la localización de agentes móviles en espacios interiores. Los avances en robótica, entornos inteligentes y vehículos autónomos han creado un campo de aplicación específico para la localización en interiores, cuyos requerimientos de precisión (en el rango de los cm) son muy superiores a los demandados por las aplicaciones de localización orientadas a personas, en cuyo contexto se han desarrollado la mayor parte de las alternativas tecnológicas. La investigación con métodos de geometría proyectiva basados en cámaras y de multilateración basados en medida de distancia con señales de radiofrecuencia de banda ancha, de ultrasonido y ópticas han demostrado un rendimiento potencial adecuado para cubrir estos requerimientos. Sin embargo, todas estas alternativas, aún en fase de investigación, presentan dificultades que limitan su aplicación práctica. En el caso de los sistemas ópticos, escasamente estudiados en este contexto, los trabajos previos se han basado en medidas de diferencia de fase de llegada de señales infrarrojas moduladas sinusoidalmente en intensidad. Una infraestructura centralizada computa medidas diferenciales, entre receptores fijos, de la señal emitida desde el móvil a posicionar, y calcula la posición del móvil mediante trilateración hiperbólica a partir de éstas. Estas investigaciones demostraron que se pueden alcanzar precisiones de pocos centímetros; sin embargo, las interferencias por multicamino debidas a la reflexión de la señal óptica en superficies del entorno pueden degradar esta precisión hasta las decenas de centímetros dependiendo de las características del espacio. Así pues, el efecto del multicamino es actualmente la principal fuente de error en esta tecnología, y por tanto, la principal barrera a superar para su implementación en situaciones reales. En esta tesis se propone y analiza un sistema de medida con señales ópticas que permite obtener estimaciones de diferencias de distancia precisas reduciendo el efecto crítico del multicamino. El sistema propuesto introduce una modulación con secuencias de ruido pseudoaleatorio sobre la modulación sinusoidal típicamente usada para medida de fase por onda continua, y aprovecha las propiedades de ensanchamiento en frecuencia de estas secuencias para reducir el efecto del multicamino. El sistema, que realiza una doble estimación de tiempo y fase de llegada, está compuesto por una etapa de sincronización que posibilita la demodulación parcialmente coherente de la señal recibida, seguida de un medidor diferencial de fase sobre las componentes desensanchadas tras la demodulación. Las condiciones de multicamino óptico típicas en espacios interiores, con una componente de camino directo claramente dominante, permiten que el proceso de demodulación recupere más potencia del camino directo que del resto de contribuciones, reduciendo el efecto del multicamino en la estimación final. Los resultados obtenidos demuestran que la aplicación del método propuesto permitiría realizar posicionamiento a partir de señales ópticas con el rendimiento adecuando para aplicaciones de robótica y guiado de vehículos en espacios interiores; además, el progresivo aumento de la potencia y el ancho de banda de los dispositivos optoelectrónicos disponibles permite esperar un incremento considerable de las prestaciones de la propuesta en los próximos años
DLL architecture for OFDM based VLC transceivers in FPGA
This paper addresses the problem of achieving high bandwidth in a DLL design for OFDM based VLC broadcast systems. It describes the implementation of efficient Data Link
Layer (DLL) and Forward Error Correction (FEC) modules in a Xilinx FPGA. The proposed DLL aims at furnishing the
adequate means to fragment and route both high data-rate
(HDR) and moderate data-rate (MDR) service requests while
maintaining a continuous transmission flow. The FEC modules
aims at providing sufficient error correction capabilities with
reasonable computation overheads. Another goal was to develop
these modules under a globally asynchronous locally synchronous
paradigm, ensuring high modularity and performance
Shortest Route at Dynamic Location with Node Combination-Dijkstra Algorithm
Abstract— Online transportation has become a basic
requirement of the general public in support of all activities to go
to work, school or vacation to the sights. Public transportation
services compete to provide the best service so that consumers
feel comfortable using the services offered, so that all activities
are noticed, one of them is the search for the shortest route in
picking the buyer or delivering to the destination. Node
Combination method can minimize memory usage and this
methode is more optimal when compared to A* and Ant Colony
in the shortest route search like Dijkstra algorithm, but can’t
store the history node that has been passed. Therefore, using
node combination algorithm is very good in searching the
shortest distance is not the shortest route. This paper is
structured to modify the node combination algorithm to solve the
problem of finding the shortest route at the dynamic location
obtained from the transport fleet by displaying the nodes that
have the shortest distance and will be implemented in the
geographic information system in the form of map to facilitate
the use of the system.
Keywords— Shortest Path, Algorithm Dijkstra, Node
Combination, Dynamic Location (key words