1,280 research outputs found
Spatial Identification Methods and Systems for RFID Tags
DisertaÄŤnĂ práce je zaměřena na metody a systĂ©my pro měřenĂ vzdálenosti a lokalizaci RFID tagĹŻ pracujĂcĂch v pásmu UHF. Ăšvod je vÄ›nován popisu souÄŤasnĂ©ho stavu vÄ›deckĂ©ho poznánĂ v oblasti RFID prostorovĂ© identifikace a struÄŤnĂ©mu shrnutĂ problematiky modelovánĂ a návrhu prototypĹŻ tÄ›chto systĂ©mĹŻ. Po specifikaci cĂlĹŻ disertace pokraÄŤuje práce popisem teorie modelovánĂ degenerovanĂ©ho kanálu pro RFID komunikaci. DetailnÄ› jsou rozebrány metody měřenĂ vzdálenosti a odhadu smÄ›ru pĹ™Ăchodu signálu zaloĹľenĂ© na zpracovánĂ fázovĂ© informace. Pro účely lokalizace je navrĹľeno nÄ›kolik scĂ©nářů rozmĂstÄ›nĂ antĂ©n. Modely degenerovanĂ©ho kanálu jsou simulovány v systĂ©mu MATLAB. VĂ˝znamná část tĂ©to práce je vÄ›nována konceptu softwarovÄ› definovanĂ©ho rádia (SDR) a specifikĹŻm jeho adaptace na UHF RFID, která vyuĹľitĂ běžnĂ˝ch SDR systĂ©mĹŻ znaÄŤnÄ› omezujĂ. Diskutována je zejmĂ©na problematika prĹŻniku nosnĂ© vysĂlaÄŤe do pĹ™ijĂmacĂ cesty a poĹľadavky na signál lokálnĂho oscilátoru pouĹľĂvanĂ˝ pro směšovánĂ. Prezentovány jsou tĹ™i vyvinutĂ© prototypy: experimentálnĂ dotazovaÄŤ EXIN-1, měřicĂ systĂ©m zaloĹľenĂ˝ na platformÄ› Ettus USRP a antĂ©nnĂ pĹ™epĂnacĂ matice pro emulaci SIMO systĂ©mu. ZávÄ›reÄŤná část je zaměřena na testovánĂ a zhodnocenĂ popisovanĂ˝ch lokalizaÄŤnĂch technik, zaloĹľenĂ˝ch na měřenĂ komplexnĂ pĹ™enosovĂ© funkce RFID kanálu. Popisuje ĂşzkopásmovĂ©/širokopásmovĂ© měřenĂ vzdálenosti a metody odhadu smÄ›ru signálu. Oba navrĹľenĂ© scĂ©náře rozmĂstÄ›nĂ antĂ©n jsou v závÄ›ru ověřeny lokalizaÄŤnĂm měřenĂm v reálnĂ˝ch podmĂnkách.The doctoral thesis is focused on methods and systems for ranging and localization of RFID tags operating in the UHF band. It begins with a description of the state of the art in the field of RFID positioning with short extension to the area of modeling and prototyping of such systems. After a brief specification of dissertation objectives, the thesis overviews the theory of degenerate channel modeling for RFID communication. Details are given about phase-based ranging and direction of arrival finding methods. Several antenna placement scenarios are proposed for localization purposes. The degenerate channel models are simulated in MATLAB. A significant part of the thesis is devoted to software defined radio (SDR) concept and its adaptation for UHF RFID operation, as it has its specialties which make the usage of standard SDR test equipment very disputable. Transmit carrier leakage into receiver path and requirements on local oscillator signals for mixing are discussed. The development of three experimental prototypes is also presented there: experimental interrogator EXIN-1, measurement system based on Ettus USRP platform, and antenna switching matrix for an emulation of SIMO system. The final part is focused on testing and evaluation of described positioning techniques based on complex backscatter channel transfer function measurement. Both narrowband/wideband ranging and direction of arrival methods are validated. Finally, both proposed antenna placement scenarios are evaluated with real-world measurements.
Experiments Validating the Effectiveness of Multi-point Wireless Energy Transmission with Carrier Shift Diversity
This paper presents a method to seamlessly extend the coverage of energy
supply field for wireless sensor networks in order to free sensors from wires
and batteries, where the multi-point scheme is employed to overcome path-loss
attenuation, while the carrier shift diversity is introduced to mitigate the
effect of interference between multiple wave sources. As we focus on the energy
transmission part, sensor or communication schemes are out of scope of this
paper. To verify the effectiveness of the proposed wireless energy
transmission, this paper conducts indoor experiments in which we compare the
power distribution and the coverage performance of different energy
transmission schemes including conventional single-point, simple multi-point
and our proposed multi-point scheme. To easily observe the effect of the
standing-wave caused by multipath and interference between multiple wave
sources, 3D measurements are performed in an empty room. The results of our
experiments together with those of a simulation that assumes a similar antenna
setting in free space environment show that the coverage of single-point and
multi-point wireless energy transmission without carrier shift diversity are
limited by path-loss, standing-wave created by multipath and interference
between multiple wave sources. On the other hand, the proposed scheme can
overcome power attenuation due to the path-loss as well as the effect of
standing-wave created by multipath and interference between multiple wave
sources.Comment: This paper is submitted to IEICE IEICE Transactions on
Communications.
Concurrent Backscatter Streaming from Batteryless and Wireless Sensor Tags with Multiple Subcarrier Multiple Access
This paper proposes a novel multiple access method that enables concurrent sensor data streaming from multiple batteryless, wireless sensor tags. The access method is a pseudo-FDMA scheme based on the subcarrier backscatter communication principle, which is widely employed in passive RFID and radar systems. Concurrency is realized by assigning a dedicated subcarrier to each sensor tag and letting all sensor tags backscatter simultaneously. Because of the nature of the subcarrier, which is produced by constant rate switching of antenna impedance without any channel filter in the sensor tag, the tag-to-reader link always exhibits harmonics. Thus, it is important to reject harmonics when concurrent data streaming is required. This paper proposes a harmonics rejecting receiver to allow simultaneous multiple subcarrier usage. This paper particularly focuses on analog sensor data streaming which minimizes the functional requirements on the sensor tag and frequency bandwidth. The harmonics rejection receiver is realized by carefully handling group delay and phase delay of the subcarrier envelope and the carrier signal to accurately produce replica of the harmonics by introducing Hilbert and inverse Hilbert transformations. A numerical simulator with Simulink and a hardware implementation with USRP and LabVIEW have been developed. Simulations and experiments reveal that even if the CIR before harmonics rejection is 0dB, the proposed receiver recovers the original sensor data with over 0.98 cross-correlation
Radio Frequency Identification Technology: Applications, Technical Challenges and Strategies
Purpose - The purpose of this paper is to discuss the technology behind RFID systems, identify the applications of RFID in various industries, and discuss the technical challenges of RFID implementation and the corresponding strategies to overcome those challenges.
Design/methodology/approach - Comprehensive literature review and integration of the findings from literature. Findings - Technical challenges of RFID implementation include tag cost, standards, tag and reader selection, data management, systems integration and security. The corresponding solution is suggested for each challenge.
Research limitations/implications - A survey type research is needed to validate the results.
Practical implications - This research offers useful technical guidance for companies which plan to implement RFID and we expect it to provide the motivation for much future research in this area.
Originality/value - As the infancy of RFID applications, few researches have existed to address the technical issues of RFID implementation. Our research filled this gap
Hardware module development for RFID drone
Nowadays most of the industry or stores uses RFID (Radio Frequency Identification) technology to monitor the state of the product. But, sometimes there is a difference between registered and the real value. In big stores manual inventory is very hard, expensive and time consuming process. In the present decades many researches are going on to avoid the above problem and one of the solutions is to use drones for RFID inventory.
This project is focused on designing and developing hardware for RFID drone to aid RFID inventory and development of a software module capable for reading of tags data.
The project presents analysis of the hardware devices such as Passive UHF (Ultra High) RFID Reader, Antenna, CPU (Central Processing Unit), PSU (Power Supply Module) and other interfacing components. Selection of the devices is based on criteria such as size and weight, market options and the components which is going to be used for RFID drone. Finally, software coding to read the RFID tags
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