教学课程资源库 更多>>

关键词： Asynchronous detection   symbol synchronization   Viterbi   FM0   RFID   Gen2  

摘要： Commercial radio frequency identification (RFID) readers have to resolve collisions between tags, without sacrificing throughput. This work proposes a Viterbi joint sequence detector as well as a 2-symbol joint tag information detector that can resolve a collision between two tags in the physical layer. In sharp contrast to prior art, the proposed closed-form signal model takes into account the asynchrony level between the two collided tag responses, which is not uncommon with commercial, low-cost RFID tags that follow industry's Gen2 protocol. The asynchrony is considered as the time offset tau between the beginnings of the two tags' responses and is modeled through a derived shaping matrix that depends on the delayed tag information. Performance evaluation of the proposed detectors with simulated data under Ricean fading, as well as experimental data with software-defined radio, reveals improved performance compared to prior art, under various operating regimes. It is also shown that for different values of the parameter tau, BER does not present a monotonic behaviour. As a collateral dividend, it is found that clustering techniques on the filtered received signal should explicitly take into account the time offset tau, since the latter modifies the number of observed clusters.

关键词： Cartesian feedback   isolation leakage cancellation   radio frequency identification (RFID)   receiver  

摘要： UHF RFID reader suffers from a strong transmitter (Tx) leakage signal coupled to a receiver (Rx), especially for an area-compact single-antenna implementation. Then, several Tx leakage cancellation schemes have been developed not to saturate the Rx and to minimize the performance degradation. This brief proposes a UHF RFID reader Rx with a low noise performance and a fast settling time by employing a digitally controlled leakage cancellation method in both passive and active realizations. A digitally-controlled passive vector reflector enhances the Tx to Rx isolation ratio by providing the optimum load impedance. An active anti-leakage feedback loop adaptively tracks the time-varying leakage and generate the phase-inverted leakage replica to suppress the leakage. The prototype chip is fabricated in a CMOS 55 nm process and the area of the chip is 2.1 mm x 1.8 mm. The passive leakage cancellation (PLC) with a vector reflector endures the 1 dBm leakage with a low Rx noise figure of 12.5 dB and 35.7 mW power consumption. The active leakage cancellation (ALC) with an anti-leakage feedback loop covers 6 dBm leakage with a fast settling time of 4.6 mu s and 58 mW power consumption.

关键词： Multi-resonator   chipless RFID   notch frequency   fabric   non-uniformity   screen printing  

摘要： Nowadays, the chipless radio frequency identification (RFID) tag is attracting significant attention owing to its immense potential in tracking. However, most of the chipless tags are fabricated on hard printed circuit boards, and the wearable fabric-based chipless tag is still in the research stage. In this paper, a symmetrical 3(rd) L-shaped multi-resonator wearable chipless RFID tag is designed and screen-printed onto fabric. In order to investigate the influence of the non-uniform conductive layer on the signal transmission at high frequency, the surface and cross-sectional topographies of the printed conductive film are analyzed and the frequency response characteristics are simulated and measured. The obtained results show that the common fabric can be used as the substrate to screen print the L-shaped multi-resonators of the chipless RFID tag, and the quality of the screen printed line, especially a narrow line, significantly affects the radio frequency performance. For the screen-printed 3(rd) L-shaped stub resonators, the relative frequency shift compared with the simulation results are 0.99%, 0.88% and 2.26%, respectively. Generally, the surface morphology of fabric and screen-printed precision are critical in improving the performance of L-shaped multi-resonators.

关键词： Vector space   Basis   Linear mapping   Authentication   RFID   Lightweight  

摘要： Internet of Things (IoT) is a novel paradigm that connects several physical devices and the cyber world over the Internet. IoT technology is growing rapidly and soon will have an enormous innovation in our daily lives. With the increasing number of connected IoT devices making our daily lives more convenient, it puts personal data at serious risk too. Radio frequency identification (RFID) contributes to IoT applications in the automatic identification of the connected devices. However, the primary concerns with the RFID tag connected devices are their security and privacy. The communication channel is deemed to be wireless or insecure between the tags and the readers, which makes RFID system vulnerable to the various known attacks. To deal with these security flaws, we have put forward a novel vector-space-based lightweight RFID authentication protocol for IoT environment named VLPRAP. The proposed protocol integrates vector space, linear mapping and basis mechanism that achieves secure authentication and improves security and privacy without increasing the computational cost. The correctness of the proposed VLPRAP protocol has been validated using BAN logic inference rules. The formal and informal security analysis demonstrates that our proposed protocol resists various malicious security threats, providing better security and higher efficiency. Furthermore, the performance analysis of our proposed protocol has been measured in terms of computation operations, storage requirement and communication overhead, which shows that better performance as compared to related existing protocols.

关键词： Ferrite core   mutual inductance   radio frequency identification (RFID)   solenoid antenna   underground  

摘要： Mutual inductance is a crucial parameter in the design and optimization of coupled antennas in underground radio frequency identification (RFID) systems. In this article, a simple and accurate modeling method for determining the mutual inductance between two coaxial solenoid antennas with a large ferrite core is proposed. This proposed model is verified by comparing the results obtained from the commonly used method for small ferrite core antennas, high-precision filament method, and finite element method (FEM). An experimental setup has also been built to validate the proposed method. This new method for predicting mutual inductance has greater adaptability and higher accuracy, and is much better suitable to optimize the performance of RFID antennas with a large ferrite core.

关键词： Radiofrequency identification   Visualization   Radio frequency   Indoor navigation   Urban areas   Indoor environment   IEEE transactions   Electronics technology   Indoor environments   Indoor location   Indoor navigation   Orientation   Radiofrequency communication   RFID   Visually impaired people  

摘要： This paper presents a study of the main contributions, in terms of the development of electronics and RFID technologies, to assist people with visual disabilities in their mobilization in indoor spaces. The main aspects taken into consideration when designing an assistive system for people with visual impairments for planning and execution of a movement from one place to another and/or for exploration of a site of interest autonomously are included. This study is important to identify the main technologies based on circuits and systems, electronics, ICT, and RF communication that have been proposed to help people with this type of disability in their indoor mobilization, as well as the techniques of location, navigation, orientation, and detection of objects, among other important functionalities for this type of systems. This work allowed us to propose the conceptual design of a novel system based on RFID and electronics technologies to help visually impaired people in their navigation in indoor environments, which will contribute to their social inclusion.

关键词： UHF antennas   Antennas   Integrated circuits   Heating systems   RFID tags   Coatings   Water hearing   Received signal strenth indicator   Clothing   Wearable sensors  

摘要： Ultrahigh frequency radio-frequency identification (UHF RFID) tags have shown enormous potential in wearable applications for sensing human vital signs. However, the integration of UHF RFID tags in clothing to achieve machine washability remains a challenge. In this study, we investigated different ways of protecting wearable UHF RFID tags with electro-textile antennas against repeated washing. We replaced the antennas of commercial UHF RFID tags with the antennas made from a silver-coated fabric. Twenty-three types of methods, including five integrated circuit (IC)-protection methods and seven fixation/cover methods, were compared, with each having ten identical samples. The 230 samples underwent 20 cycles of machine washing and drying, and the changes in received signal strength indicator (RSSI) and the number of failed tags after washing were recorded and analyzed statistically. We found that 1) water penetration does not have a negative impact on tag functionality, therefore, being waterproof is not a requirement for the coating material; 2) heat-bond hem taping is the most efficient IC protection method; 3) heat and high pressure is effective to improve tag endurance; and 4) fusible interlinings and ironing, used in traditional garment production, can be effective.

关键词： Surgical tray optimization   RFID   Sterile processing   Efficiency  

摘要： Background: Surgical instrument tray reduction attempts to minimize intraoperative inefficiency and processing costs. Previous reduction methods relied on trained observers manually recording instrument use (i.e. human ethnography), and surgeon and/or staff recall, which are imprecise and inherently limited. We aimed to determine the feasibility of radio frequency identification (RFID)-based intraoperative instrument tracking as an effective means of instrument reduction. Methods: Instrument trays were tagged with unique RFID tags. A RFID reader tracked instruments passing near RFID antennas during 15 breast operations performed by a single surgeon;ethnography was performed concurrently. Instruments without recorded use were eliminated, and 10 additional cases were performed utilizing the reduced tray. Logistic regression was used to estimate odds of instrument use across cases. Cohen's Kappa estimated agreement between RFID and ethnography. Results: Over 15 cases, 37 unique instruments were used (median 23 instruments/case). A mean 0.64 (median = 0, range = 0-3) new instruments were added per case;odds of instrument use did not change between cases (OR = 1.02, 95%CI 1.00-1.05). Over 15 cases, all instruments marked as used by ethnography were recorded by RFID tracking;7 RFID-tracked instruments were never recorded by ethnography. Tray size was reduced 40%. None of the 25 eliminated instruments were required in 10 subsequent cases. Cohen's Kappa comparing RFID data and ethnography over all cases was 0.82 (95%CI 0.79-0.86), indicating near perfect agreement between methodologies. Conclusions: Intraoperative RFID instrument tracking is a feasible, data-driven method for surgical tray reduction. Overall, RFID tracking represents a scalable, systematic, and efficient method of optimizing instrument supply across procedures. (C) 2021 Published by Elsevier Inc.

关键词： Inspection  

摘要： In order to solve the patrol inspection problems in cotton storage and the need for environmental monitoring in the modern cotton bale warehousing process, RFID positioning technology, wireless temperature and humidity real-time monitoring technology and handheld terminal intelligent inspection technology are used to design and develop RFID-based cotton bale intelligence Inspection and intelligent temperature and humidity monitoring system. The artificial neural network (ANN) method performs Gaussian filter processing on the system monitoring data to establish an accurate RSSI and label position classification model. The system finally realizes the functions of locating cotton bales in storage, collecting bale information, and real-time measurement and collection of temperature and humidity parameters in the cotton bale warehouse. The test results show that the relative error of RFID cotton bale intelligent inspection and monitoring system positioning and monitoring does not exceed 6.7%, effectively improving the work efficiency of inspectors and the safety of cotton bale storage. The relative error of temperature is less than 8%, and the relative error of humidity is less than 7%. It can display the storage environment temperature in real time and meet the real-time requirements. It improves the effective positioning and inspection of the cotton stack by management personnel, prevents the loss of cotton bale and reduces the probability of cotton stack deterioration. © 2021, CC BY.

摘要： The proposed RFID reader antenna progressed with perfect electric conductor (PEC) as the radiating element and FR 4 as the substrate to achieve circular polarization, enhancement in bandwidth, and read range. The design presents a CPW feed RFID antenna for near-field reading applications, between the range of 903 MHz to 929 MHz. The operating frequency of the proposed design is 900 MHz, axial ratio of the model is less than 3 dB, impedance bandwidth is 256 MHz, and axial bandwidth is 36 MHz, proving to be adequate for near-field RFID reader applications such as item-level tagging and smart shelf. The proposed antenna model is realized with fractal structure to achieve miniaturization. The developed antenna is optimized using EM software for numerical analysis. The designed antenna is fabricated, and the prototype is characterized in terms of dielectric constant and loss tangent. The obtained results indicate high correlation with simulation results.