Caraoke: An E-Toll Transponder Network for Smart Cities

Electronic toll collection transponders, e.g., E-ZPass, are a widely-used wireless technology. About 70% to 89% of the cars in US have these devices, and some states plan to make them mandatory. As wireless devices however, they lack a basic function: a MAC protocol that prevents collisions. Hence, today, they can be queried only with directional antennas in isolated spots. However, if one could interact with e-toll transponders anywhere in the city despite collisions, it would enable many smart applications. For example, the city can query the transponders to estimate the vehicle flow at every intersection. It can also localize the cars using their wireless signals, and detect those that run a red-light. The same infrastructure can also deliver smart street-parking, where a user parks anywhere on the street, the city localizes his car, and automatically charges his account. This paper presents Caraoke, a networked system for delivering smart services using e-toll transponders. Our design operates with existing unmodified transponders, allowing for applications that communicate with, localize, and count transponders, despite wireless collisions. To do so, Caraoke exploits the structure of the transponders' signal and its properties in the frequency domain. We built Caraoke reader into a small PCB that harvests solar energy and can be easily deployed on street lamps. We also evaluated Caraoke on four streets on our campus and demonstrated its capabilities.National Science Foundation (U.S.

A Novel Long-Range Passive UHF RFID System over Twisted-pair Cable

Radio Frequency Identification (RFID) is one of the most representative, rapidly growing, and highly extendable technologies, which uses electromagnetic waves in accordance with specific communications standards and regulations to identify, track, or even localise desired objects. However, due to its high cost, limited read range, and uncertain reliability, its adoption still lags, especially in large-scale organisations. Even though an RFID distributed antenna system (DAS) can greatly improve the detection range and read rate of a single reader when system uses different combinations of antenna states with frequency and phase hopping, the lossy and heavy coaxial cables between reader and antennas still limits the system coverage and design flexibility for wide-area passive UHF RFID applications. In order to develop a cost-efficient and flexibly-installed passive RFID DAS, a novel large-range passive UHF RFID system over twisted-pair cable is proposed in this dissertation. This new system consists of one baseband central controller and one antenna subsystem, connected by a commonly used twisted-pair cable. It is shown that transmitting/receiving low frequency baseband signals over a twisted-pair cable can significantly reduce cable attenuation and extend the communication distance. A simulation is conducted to demonstrate that frequency and phase hopping can also be remotely controlled to fit this system structure by slightly varying the frequency or phase of the input reference signal of the frequency synthesis system. The features of twisted-pair cable in terms of its low cost, light weight, and bend radius greatly improve the design and installation flexibility of an RFID system. The implemented system is designed based on the ISO 18000-6C and EPC Class 1 Generation 2 standards, and can operate according to FCC (902-928 MHz) and ETSI (865-868MHz) regulations. The results of the measurement show the reader can achieve a sensitivity of - 94.5 dBm over 30 m Cat5e cable, and its sensitivity can still remain at around -94.2 dBm over 150 m Cat5e cable. The experimental results of tag detection show that the passive tags can be successfully detected over a 6 m wireless range following a 300 m of twisted-pair cable between the central controller and antenna. This detection range cannot be achieved by existing commercial RFID systems. Since the transmission and reception in a RFID system are simultaneous, finite isolation of the circulator/directional coupler and environmentally dependent reflection ratio of the antenna lead to serious leakage problems. Leakage can directly cause sensitivity degradation due to saturation of the RF components. A fast leakage suppression block is developed in efforts to solve this problem. Measurements show that this new canceller can deliver an average suppression of 36.9 dB, and this excellent performance remains when the system uses frequency hopping. With help of an improved scanning algorithm, this canceller can find its optimal status within 38 ms, and this settling time is short enough for most commercial RFID readers. By reducing the number of voltage samples taken, the convergence time can be further improved. To fully investigate this new passive UHF RFID system value, a comparison study between the new system and a commercial system is conducted. This new automatic passive UHF RFID system is confirmed to deliver high performance long-range passive tag detection. Particular advantages are shown in the fast tag read rate and capability of uplink SNR improvement. This novel system is also superior to conventional RFID systems in terms of link distance, link cost, and installation flexibility

Physical Layer Approach for Securing RFID Systems

Radio Frequency IDentification (RFID) is a contactless, automatic identification wireless technology primarily used for identifying and tracking of objects, goods and humans. RFID is not only limited to identification and tracking applications. This proliferating wireless technology has been deployed in numerous securities sensitive applications e.g. access control, e-passports, contactless payments, driver license, transport ticking and health cards. RFID inherits all the security and privacy problems that are related to wireless technology and in addition to those that are specific to RFID systems. The security and privacy protection schemes proposed in literature for wireless devices are mostly secured through symmetric/asymmetric keys encryption/decryption and hash functions. The security of all these cryptographic algorithms depends on computationally complex problems that are hard to compute using available resources. However, these algorithms require cryptographic operations on RFID tags which contradict the low cost demand of RFID tags. Due to limited number of logic gates in tags, i.e., 5K-10K, these methods are not practical. Much research effort has done in attempt to solve consumer's privacy and security problem. Solutions that prevent clandestine inventory are mostly application layer techniques. To solve this problem, a new RFID physical layer scheme has been proposed namely Direct Sequence Backscatter Encryption (DSB Enc). The proposed scheme uses level generator to produce different levels before transmitting the signal to the tag. The tag response to the signal sent by the reader using backscatter communications on the same signal which looks random to the eavesdropper. Therefore eavesdropper cannot extract the information from reader to tag and tag to reader communication using passive eavesdropping. As reader knows the different generated levels added to the carrier signal, it can remove the levels and retrieve the tag's messages. We proposed a lightweight, low-cost and practically secure physical layer security to the RFID system, for a supply chain processing application, without increasing the computational power and tag's cost. The proposed scheme was validated by simulations on GNU Radio and experimentation using SDR and a WISP tag. Our implementation and experimental results validate that DSB Enc is secure against passive eavesdropping, replay and relay attacks. It provides better results in the presence of AWGN channel.1 yea

Sistemas eficientes de transmissão de energia sem-fios e identificação por radiofrequência

Doutoramento em Engenharia EletrotécnicaIn the IoT context, where billions of connected objects are expected to be ubiquitously deployed worldwide, the frequent battery maintenance of ubiquitous wireless nodes is undesirable or even impossible. In these scenarios, passive-backscatter radios will certainly play a crucial role due to their low cost, low complexity and battery-free operation. However, as passive-backscatter devices are chiefly limited by the WPT link, its efficiency optimization has been a major research concern over the years, gaining even more emphasis in the IoT context. Wireless power transfer has traditionally been carried out using CW signals, and the efficiency improvement has commonly been achieved through circuit design optimization. This thesis explores a fundamentally different approach, in which the optimization is focused on the powering waveforms, rather than the circuits. It is demonstrated through theoretical analysis, simulations and measurements that, given their greater ability to overcome the built-in voltage of rectifying devices, high PAPR multi-sine (MS) signals are capable of more efficiently exciting energy harvesting circuits when compared to CWs. By using optimal MS signals to excite rectifying devices, remarkable RF-DC conversion efficiency gains of up to 15 dB with respect to CW signals were obtained. In order to show the effectiveness of this approach to improve the communication range of passive-backscatter systems, a MS front-end was integrated in a commercial RFID reader and a significant range extension of 25% was observed. Furthermore, a software-defined radio RFID reader, compliant with ISO18000-6C standard and with MS capability, was constructed from scratch. By interrogating passive RFID transponders with MS waveforms, a transponder sensitivity improvement higher than 3 dB was obtained for optimal MS signals. Since the amplification and transmission of high PAPR signals is critical, this work also proposes efficient MS transmitting architectures based on space power combining techniques. This thesis also addresses other not less important issues, namely self-jamming in passive RFID readers, which is the second limiting factor of passive-backscatter systems. A suitable self-jamming suppression scheme was first used for CW signals and then extended to MS signals, yielding a CW isolation up to 50 dB and a MS isolation up 60 dB. Finally, a battery-less remote control system was developed and integrated in a commercial TV device with the purpose of demonstrating a practical application of wireless power transfer and passive-backscatter concepts. This allowed battery-free control of four basic functionalities of the TV (CH+,CH-,VOL+,VOL-).No contexto da internet das coisas (IoT), onde são esperados bilhões de objetos conectados espalhados pelo planeta de forma ubíqua, torna-se impraticável uma frequente manutenção e troca de baterias dos dispositivos sem fios ubíquos. Nestes cenários, os sistemas radio backscatter passivos terão um papel preponderante dado o seu baixo custo, baixa complexidade e não necessidade de baterias nos nós móveis. Uma vez que a transmissão de energia sem fios é o principal aspeto limitativo nestes sistemas, a sua otimização tem sido um tema central de investigação, ganhando ainda mais ênfase no contexto IoT. Tradicionalmente, a transferência de energia sem-fios é feita através de sinais CW e a maximização da eficiência é conseguida através da otimização dos circuitos recetores. Neste trabalho explora-se uma abordagem fundamentalmente diferente, em que a otimização foca-se nas formas de onda em vez dos circuitos. Demonstra-se, teoricamente e através de simulações e medidas que, devido à sua maior capacidade em superar a barreira de potencial intrínseca dos dispositivos retificadores, os sinais multi-seno (MS) de elevado PAPR são capazes de excitar os circuitos de colheita de energia de forma mais eficiente quando comparados com o sinal CW tradicional. Usando sinais MS ótimos em circuitos retificadores, foram verificadas experimentalmente melhorias de eficiência de conversão RF-DC notáveis de até 15 dB relativamente ao sinal CW. A fim de mostrar a eficácia desta abordagem na melhoria da distância de comunicação de sistemas backscatter passivos, integrou-se um front-end MS num leitor RFID comercial e observou-se um aumento significativo de 25% na distância de leitura. Além disso, desenvolveu-se de raiz um leitor RFID baseado em software rádio, compatível com o protocolo ISO18000-6C e capaz de gerar sinais MS, com os quais interrogou-se transponders passivos, obtendo-se ganhos de sensibilidade dos transponders maiores que 3 dB. Uma vez que a amplificação de sinais de elevado PAPR é uma operação crítica, propôs-se também novas arquiteturas eficientes de transmissão baseadas na combinação de sinais em espaço livre. Esta tese aborda também outros aspetos não menos importantes, como o self-jamming em leitores RFID passivos, tido como o segundo fator limitativo neste tipo de sistemas. Estudou-se técnicas de cancelamento de self-jamming CW e estendeu-se o conceito a sinais MS, tendo-se obtido isolamentos entre o transmissor e o recetor de até 50 dB no primeiro caso e de até 60 dB no segundo. Finalmente, com o objetivo de demonstrar uma aplicação prática dos conceitos de transmissão de energia sem fios e comunicação backscatter, desenvolveu-se um sistema de controlo remoto sem pilhas, cujo protótipo foi integrado num televisor comercial a fim de controlar quatro funcionalidades básicas (CH+,CH-,VOL+,VOL-)

Design And Implementation Of A Low-cost, Compact And Long Range Monostatic Uhf Rfid Reader With Read Point Extension

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2014Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2014RFiD sistemlerinin çeşitli uygulama alanlarında artan popülerliği neticesinde, özelikle UHF bandında çalışacak olan RFiD okuyucu üretimine dair ihtiyaçlar gittikçe artan bir eğilim göstermektedir. Bahsedilen ihtiyaçlar göz önüne alınarak, bu tez kapsamında yeni bir okuyucu tasarımı gerçekleştirilmiştir. Tasarlanan okuyucu, endüstriyel RFiD uygulamaları için gerekli görülen birçok ilgi çekici özelliği bünyesinde barındırmaktadır. RFiD sistemleri, kısaca radyo frekanslı kimliklendirme diye tanımlanabilmektedir. Elektromanyetik dalgaları kullanarak (kablosuz iletişim), üzerlerine RFiD etiketleri iliştirilmiş olan nesne, hayvan ve insanlardan verilerin transfer edilmesini sağlarlar. Takip, gözlem, kontrol vb. amaçlı kullanılabilmektedir. Genel itibari ile barkod sistemi gibi otomatik tanımlama teknolojileri ailesinin bir üyesidir. Tez kapsamındaki ilk iki bölümde, RFiD sisteminin detaylarına ve temel standartlarına dair bilgilere yer verilmiştir. Üçüncü bölümde, donanım sistem tasarımına ait süreçler detaylı bir şekilde ele alınmış ve simülasyon ile ölçüm sonuçlarına yer verilmiştir. Tasarlanan okuyucu; okuma noktası artırılmış, düşük maliyetli, kompakt, uzun menzilli ve Gen2 uyumlu olacak şekilde UHF bandında geliştirilmiştir. Aynı zamanda, birden fazla okuyucunun aynı anda çalıştığı yoğun ortamlarda çalışabilme özelliğine sahiptir. Okuyucu, anten çıkış gücü 30-dBm olan iki adet anten çıkış portu barındırmaktadır. Ayrıca, yenilikçi bir özellik olarak, geri yansıyan RF gücünü azaltmak için anten uydurma devresi tasarlanmıştır. Bu işlem, okuyucunun çıkış empedansının antenin empedansına uydurulması ile gerçekleştirilmektedir. Bununla birlikte, okuyucu, işlem anında antenin empedansını olası çevresel faktörlere karşı kararlı bir yapıda tutabilme kabiliyetine de sahiptir. Bunların yanı sıra, bir güç algılayıcı devresi vasıtasıyla, okuyucu için var olan yasal koşulları sağlamak adına, çıkış gücünü sınırlandırma ve kontrol etme özellikleri de mevcuttur. Donanım tasarımı esnasında, yüksek frekansta PCB tasarım teknikleri, radyo frekansı ve fizik temelleri, dijital ve analog devre tasarım teknikleri gibi farklı disiplinlerden çeşitli teknik bilgiler ve kabiliyetler kullanılmıştır. Artırılmış okuma noktası özelliği, tasarlanan bir başka donanım, RF çoklayıcı devresi, vasıtası ile sağlanmaktadır. Bu ürün sayesinde, UHF RFiD okuyucunun anten çıkışları artırılarak sistem kurulum maliyeti azaltılmaktadır. Bu cihazın amacı, çoklu anten ihtiyacı olan uygulamalarda okuyucu sayısını sabit tutarak, anten çıkış sayısını artırmaktır. Bu sayede sistemin uygulanma maliyetinde avantaj sağlanmaktadır. Ürün dahilindeki anahtarlama entegrelerinin araya girme kayıplarının az olması ve entegrelerin kontrolünü sağlayan denetleyici yapısı, okuyucuların marka modelinden bağımsız tak-çalıştır sistem modeli ürüne ait katma değerli nitelikleridir. Bu tez dahilinde tasarımı gerçekleştirilen UHF RFiD okuyucu, aynı zamanda Bilim, Sanayi ve Teknoloji Bakanlığı’nın sağlamış olduğu Ar-Ge proje destekleri kapsamında desteklenmiştir. Bu proje ve tez neticesinde, imalat masraflarını düşürmek adına okuyucu tasarımı ve üretimi yerli olarak gerçekleştirilmiş ve yurt içinde milli bir cihaz geliştirilmiştir. Proje sonucunda, başlangıçta belirlenen tüm kıstaslar başarıyla sağlanmış ve birer adet RF çoklayıcı devresi ve UHF RFiD okuyucu devresi, kontrol ünitesi ve grafiksel arayüz yazılımı ile birlikte, istenen herhangi bir RFiD uygulamasında kullanılmak üzere prototip olarak üretilmiştir.RFiD systems have an increasing popularity in various kinds of applications. Necessities are rising for the manufacture of new RFiD readers in industry especially at UHF band. Based on this concept, a new UHF RFiD reader design with extended read point capability has been presented within the scope of this thesis. Designed reader has attractive features required by some industrial RFiD applications. Before the hardware design part of the study, first, the background of RFiD and its key standards have been introduced in the first two chapters. In the third chapter, the hardware design process has been covered in detail and simulation and measurement results have been presented. The designed hardware is a low-cost, compact and long-range Gen2 compliant UHF RFiD reader with extended read point capability. The reader has up to 30 dBm (1 Watt) output RF power at two selectable antenna ports. The reader has an antenna tuning circuit, a novel feature, to reduce reflected RF power from antennas. This is achieved by tuning output impedance of the reader to the impedance of antenna. The reader can also tune the antenna impedance during operation in case the environment of the antenna changes. A power detector is used to control and limit the output power to regulatory requirements. While designing the hardware, several technical skills within a wide spectrum of disciplines were used like PCB design in high frequency, radio frequency, physics of RF, digital and analog design. Extended read point capability is provided with another hardware design called RF multiplexer circuit. This product has been designed in order to increase the number of antenna output ports of UHF RFiD reader to reduce the system implementation cost in dense antenna applications. This hardware design is also a part of another Research & Development project funded by the Ministry of Science, Industry and Technology of Turkey. As a part of this project and this thesis, the UHF RFiD reader has been designed as a domestic product to lower the cost of manufacture. As a result of this project, all the objectives have been achieved and a prototype of UHF RFiD reader, which has a control unit and a graphical user interface, and an RF multiplexer have been manufactured to be used in any desired UHF RFiD application.Yüksek LisansM.Sc

Software-hardware systems for the Internet-of-Things

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.Cataloged from PDF version of thesis.Includes bibliographical references (pages [187]-201).Although interest in connected devices has surged in recent years, barriers still remain in realizing the dream of the Internet of Things (IoT). The main challenge in delivering IoT systems stems from a huge diversity in their demands and constraints. Some applications work with small sensors and operate using minimal energy and bandwidth. Others use high-data-rate multimedia and virtual reality systems, which require multiple-gigabits-per-second throughput and substantial computing power. While both extremes stress the computation, communications, and energy resources available to the underlying devices, each intrinsically requires different solutions to satisfy its needs. This thesis addresses both bandwidth and energy constraints by developing custom software-hardware systems. To tackle the bandwidth constraint, this thesis introduces three systems. First, it presents AirShare, a synchronized abstraction to the physical layer, which enables the direct implementation of diverse kinds of distributed protocols for loT sensors. This capability results in a much higher throughput in today's IoT networks. Then, it presents Agile-Link and MoVR, new millimeter wave devices and protocols which address two main problems that prevent the adoption of millimeter wave frequencies in today's networks: signal blockage and beam alignment. Lastly, this thesis shows how these systems enable new IoT applications, such as untethered high-quality virtual reality. To tackle the energy constraint, this thesis introduces a VLSI chip, which is capable of performing a million-point Fourier transform in real-time, while consuming 40 times less power than prior fast Fourier transforms. Then, it presents Caraoke, a small, low-cost and low-power sensor, which harvests its energy from solar and enables new smart city applications, such as traffic management and smart parking.by Omid Salehi-Abari.Ph. D

Automated multi-functional smart home system using arduino

Evin ve ev aletlerinin durumunu izlemek, her zaman insanların günlük yaşamının ana kaygıları arasındadır. Bu endişe, gün içinde dışarıda kalanlar ve çocuklarına ya da yaşlılarına sekmeleri tutmak zorunda olanlar için çok daha belirgindir. Bazı durumlarda ev güvenliğini en üst düzeye çıkarmak da önerilmektedir. Akıllı ev, ev aletlerini izlemek için bilgi teknolojisi ve bilgisayarları veya akıllı telefonları kullanan bir sistem anlamına gelir. Bu teknoloji, yukarıda açıklanan endişeleri başarılı bir şekilde çözebilir. Bu tezde, güvenliğin sağlanması (hırsızlık tespiti ve mobil uyarıların bildirilmesi), güvenlik ve konfor (istenilen ev sıcaklığının ayarlanması, ortam aydınlatmasının ayarlanması) ve ev aletlerinin kontrol edilmesi gibi çeşitli aşamalarda pratikte akıllı bir ev uygulayan bir yöntem önerilmiştir. cep telefonları ve GSM ile. Önerilen yöntemin uygulanmasından elde edilen sonuçlar, önerilen yöntemin bir akıllı ev sisteminin uygulanmasının maliyetini azaltabildiğini ve güvenlik, emniyet ve uzaktan kumanda gibi faktörleri gerçekleştirirken bunu kamuya kullanma becerisini sağladığını göstermektedir. akıllı cihazlarla ev aletleri