An official website of the United States government
Currently, there is an increasing interest in the use of RFID systems with passive or battery-less tags with sensors incorporated, also known as computational RFID (CRFID) systems. These passive tags use the reader signal to power up their microcontroller and an attached sensor. Following the current standard EPC C1G2, the reader must identify the tag (receive the tag's identification code) prior to receive data from its sensor. In a typical RFID scenario, several sensor tags share the reader interrogation zone, and during their identification process, their responses often collide, increasing their identification time. Therefore, RFID application developers must be mindful of tag anti-collision protocols when dealing with CRFID tags in dense RFID sensor networks. So far, significant effort has been invested in simulation-based analysis of the performance of anti-collision protocols regarding the tags identification time. However, no one has explored the experimental performance of anti-collision protocols in an RFID sensor network using CRFID. This paper: (i) demonstrates that the impact of one tag identification time over the total time required to read one sensor data from that same tag is very significant, and (ii) presents an UHF-SDR RFID system which validates the improvement of FuzzyQ, a fast anticollision protocol, in relation to the protocol used in the current RFID standard.
more »
« less
A Single-Aperture, Single-Pixel Reader for Optical Frequency Identification
This paper presents a single-aperture, single-pixel reader for communication with Optical Frequency Identification (OFID) tags. OFID tags use solar cells to transmit and receive information wirelessly as well as to harvest radiant energy. Due to its single-aperture architecture, the reader's optical system provides a shared optical path for reception and transmission. Also, physical alignment between the reader and an OFID tag is visually guided using the reader's emitted light, securing a robust data link as long as the OFID tag is illuminated. In this paper, a description of the reader's optical and electronic sub-systems are presented. The transmitter and receiver circuits are described in detail. The transmitter, built with a linear LED driver, achieves a power efficiency of nearly 87%. The receiver, featuring a third-order bandpass filter, reduces both low-frequency and high-frequency ambient noise. A prototype of the reader was fabricated and housed in a custom 3D-printed enclosure. Test results show that the reader is able to receive modulated luminescent signals from an OFID tag at a distance of 1 m and at a data rate of 3 kbps.
more »
« less
- Award ID(s):
- 1809637
- PAR ID:
- 10297634
- Date Published:
- Journal Name:
- 2021 IEEE International Symposium on Circuits and Systems (ISCAS)
- Page Range / eLocation ID:
- 1 to 5
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Radio frequency identification (RFID) is a technology for automated identification of objects and people. RFID technology is expected to find extensive use in applications related to the Internet of Things, and in particular applications of Internet of Battlefield Things. Of particular interest are passive RFID tags due to a number of their salient advantages. Such tags, lacking energy sources of their own, use backscattering of the power of an RF source (a reader) to communicate. Recently, passive RFID tag-to-tag (T2T) communication has been demonstrated, via which tags can directly communicate with each other and share information. This opens the possibility of building a Network of Tags (NeTa), in which the passive tags communicate among themselves to perform data processing functions. Among possible applications of NeTa are monitoring services in hard-to-reach locations. As an essential step toward implementation of NeTa, we consider a novel multi-hop network architecture; in particular, with the proposed novel turbo backscattering operation, inter-tag distances can be significantly increased. Due to the interference among tags’ transmissions, one of the main technical challenges of implementing such the NeTa architecture is the routing protocol design. In this paper, we introduce a design of a routing protocol, which is based on a solution of a non-linear binary optimization problem. We study the performance of the proposed protocol and investigate impacts of several network factors, such as the tag density and the transmit power of the reader.more » « less
-
PACT: Scalable, Long-Range Communication for Monitoring and Tracking Systems Using Battery-less TagsThe food and drug industry is facing the need to monitor the quality and safety of their products. This has made them turn to low-cost solutions that can enable smart sensing and tracking without adding much overhead. One such popular low-power solution is backscatter-based sensing and communication system. While it offers the promise of battery-less tags, it does so at the cost of a reduced communication range. In this work, we propose PACT - a scalable communication system that leverages the knowledge asymmetry in the network to improve the communication range of the tags. Borrowing from the backscatter principles, we design custom PACT Tags that are battery-less but use an active radio to extend the communication range beyond standard passive tags. They operate using the energy harvested from the PACT Source. A wide-band Reader is used to receive multiple Tag responses concurrently and upload them to a cloud server, enabling real-time monitoring and tracking at a longer range. We identify and address the challenges in the practical design of battery-less PACT Tags using an active radio and prototype them using off-the-shelf components. We show experimentally that our Tag consumes only 23μJ energy, which is harvested from an excitation Source that is up to 24 meters away from the Tag. We show that in outdoor deployments, the responses from an estimated 520 Tags can be received by a Reader concurrently while being 400 meters away from the Tags.more » « less
-
This paper presents a wireless temperature sensor that uses a GaAs solar cell as a wireless transmitter of information. Transmission of information with a solar cell is possible by modulating the luminescent radiation emitted by the solar cell. This technique, dubbed Optical Frequency Identification or OFID, was recently reported in the literature and in this work is used to transmit temperature measurements wirelessly. The hardware design of an OFID temperature sensor tag and its corresponding reader is described. A prototype of the proposed sensor was built as a proof of concept. Experimental results demonstrate wireless data transmission at a distance of 1 m distance and at a bit rate of 1200 bps. The wireless temperature sensor has a maximum error of 0.39°C (after calibration) with respect to a high-precision temperature meter.more » « less
-
In dense RFID systems, efficient coordination of multiple readers is crucial to prevent reader-to-reader interference (RRI) and ensure optimal system performance. As the number of readers and tags increases, static frequency and time-slot assignment become insufficient to handle dynamic network conditions, leading to collisions, missed tag reads, and degraded throughput. In this paper, we propose a decentralized neigh-borhood discovery and management scheme for RFID systems operating in high-density environments. Our approach minimizes interference and improves tag read accuracy by dynamically adjusting communication parameters like frequency and time slots based on current system conditions, which are updated by periodic information exchanges among readers. Experimental results demonstrate that the proposed method significantly improves system scalability, throughput, and reliability. The proposed framework offers a scalable and adaptive solution for dense reader environments.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/ISCAS51556.2021.9401470
