Empowering the blind: contactless activity recognition with commodity software-defined radio and ultra-high-frequency radio frequency identification

his study presents a novel computational radio frequency identification (RFID) system designed specifically for assisting blind individuals, utilising software-defined radio (SDR) with coherent detection. The system employs battery-less ultra-high-frequency (UHF) tag arrays in Gen2 RFID systems, enhancing the transmission of sensed information beyond standard identification bits. Our method uses an SDR reader to efficiently manage multiple tags with Gen2 preambles implemented on a single transceiver card. The results highlight the system’s real-time capability to detect movements and direction of walking within a four-meter range, indicating significant advances in contactless activity monitoring. This system not only handles the complexities of multiple tag scenarios but also delineates the influence of system parameters on RFID operational efficiency. This study contributes to assistive technology, provides a platform for future advancements aimed at addressing contemporary limitations in pseudo-localisation, and offers a practical, affordable assistance system for blind individuals

Artificial intelligence and multiple criteria decision making approach for a cost-effective RFID-enabled tracking management system

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonThe implementation of RFID technology has been subject to ever-increasing popularity in relation to the traceability of items as one of the most advance technologies. Implementing such a technology leads to an increase in the visibility management of products. Notwithstanding this, RFID communication performance is potentially greatly affected by interference between the RFID devices. It is also subject to auxiliary costs in investment that should be considered. Hence, seeking a cost-effective design with a desired communication performance for RFID-enabled systems has become a key factor in order to be competitive in today‟s markets. This study introduce a cost and performance-effective design for a proposed RFID-enabled passport tracking system through the development of a multi-objective model that takes in account economic, operation and social criteria. The developed model is aimed at solving the design problem by (i) allocating the optimal numbers of related facilities that should be established and (ii) obtaining trade-offs among three objectives: minimising implementation and operational costs; minimising RFID reader interference; and maximising the social impact measured in the number of created jobs. To come closer to the actual design in terms of considering the uncertain parameters, a fuzzy multi-objective model was developed. To solve the multi-objective optimization problem model, two solution methods were used respectively (epsilon constrain and linear programming) to select the best Pareto solution and a decision-making method was developed to select the final trade-off solution. Moreover, this research aims to provide a user-friendly decision making tool for selecting the best vendor from a group which submitted their tenders for implementing a proposed RFID- based passport tracking system. In addition to that a real case study was applied to examine the applicability of the developed model and the proposed solution methods. The research findings indicate that the developed model is capable of presenting a design for an RFID- enabled passport tracking system. Also, the developed decision-making tool can easily be used to solve similar vendor selection problem. Research findings demonstrate that the proposed RFID-enabled monitoring system for the passport tracking system is economically feasible. The study concludes that the developed mathematical models and optimization approaches can be a useful decision-maker for tackling a number of design and optimization problems for RFID system using artificial intelligence mathematical algorithm based techniques

Single-antenna coherent detection of collided FM0 RFID signals

Δημοσίευση σε επιστημονικό περιοδικόSummarization: This work derives and evaluates single-antenna detection schemes for collided radio frequency identification (RFID) signals, i.e. simultaneous transmission of two RFID tags, following FM0 (biphase-space) encoding. In sharp contrast to prior art, the proposed detection algorithms take explicitly into account the FM0 encoding characteristics, including its inherent memory. The detection algorithms are derived when error at either or only one out of two tags is considered. It is shown that careful design of one-bit-memory two-tag detection can improve bit-error-rate (BER) performance by 3dB, compared to its memoryless counterpart, on par with existing art for single-tag detection. Furthermore, this work calculates the total tag population inventory delay, i.e. how much time is saved when two-tag detection is utilized, as opposed to conventional, single-tag methods. It is found that two-tag detection could lead to significant inventory time reduction (in some cases on the order of 40%) for basic framed-Aloha access schemes. Analytic calculation of inventory time is confirmed by simulation. This work could augment detection software of existing commercial RFID readers, including single-antenna portable versions, without major modification of their RF front ends.Presented on: IEEE Transactions on Communication

Ambient backscatterers for low cost and low power wireless applications

Sensors that are used in Internet-of-Things (IoT) area are hampered by extremely high costs and excessive battery power consumption – but wireless, reflective, sensor-tags could help address these issues. In agricultural applications: in order to monitor a field of 500 plants, the operating cost will typically rack up hundreds of pounds per field and will gobble tens of milliwatts per sensor. In this thesis we have tried to address some of these shortfalls by opting for each plant to have an antenna, one transistor that acts as a switch, and one microcontroller. Each sensor uses wireless communication based on a reflections technology known as backscatter. The antenna acts as a mirror and when it is illuminated with a signal, it reflects back the wave. The signal comes from an FM radio station and it is freely available in the air. The plant-sensor can modulate the information by a very smart switching of this antenna. We are trying, under laboratory conditions, to combine this low power, low-cost technology with tape-based, flexible nanomaterial printed sensors. As nanotechnology enables flexible inkjet printed electronics to revolutionise IoT applications, we developed a new technology and we hope that our nanomaterial based printed circuit sensors will help push state-of-the-art additive manufacturing in agricultural technology