Current Issue : January - March Volume : 2014 Issue Number : 1 Articles : 5 Articles
In this contribution, we describe and analyse a miniature wireless radio frequency identification (RFID) chip with\r\non-chip antennas (OCA) and ultra wideband (UWB) signalling by real-world measurements. With the on-chip antenna\r\napproach, no external antennas are required, and the size of the overall tag is identical to the size of the chip alone\r\n(3.5mm Ã?â?? 1 mm). The chip is powered through inductive coupling and controlled by an RFID signal at 866 MHz in the\r\ndownlink, while the uplink transmits a quaternary pulse-position-modulated (4-PPM) UWB signal at 5.64 GHz with\r\npulses having a duration in the order of nanoseconds. In this contribution, the hybrid or asymmetric communication\r\nscheme between prototype chip and reader, the embedded OCA, and the measurement setup are described. The\r\nprototype achieves 4-PPM bit rate of 126 Mbit/s based on a pulse-train transmission with a duration of 10 Ã?µs. The\r\nsmall size, high data rate, and fine time resolution of the UWB impulse radio offer new features and sensing\r\ncapabilities for future RFID-like applications....
In this contribution, the author examines the feasibility of on-body backscatter radio frequency identification (RFID)\r\nsystems in the ultra high frequency range. Four different on-body RFID systems are investigated operating monopoles\r\nor patch antennas at 900 MHz or 2.45 GHz. The systems� feasibility is analyzed by means of on-body channel\r\nmeasurements in a realistic test environment. The measured channel transfer functions allow to evaluate if enough\r\npower is available for a reliable backscatter communication. This evaluation is done with the aid of outage\r\nprobabilities in the forward link and the backward link of the systems. Using these probabilities, the on-body systems\r\nprove feasible when using state-of-the-art reader and transponder chips. In particular, the use of semi-passive RFID\r\ntransponder chips leads to a reliable performance in the systems� forward links. The robust performance of the\r\nsystems� backward links is clearly shown for the 900 MHz monopole antenna configuration, while the limitations in the\r\nbackward links of the other systems have to be overcome by the use of a second reader unit on the person�s back. The\r\nnovel feasibility analysis presented here allows to examine each system parameter individually and thus leads to\r\nreliable and robust backscatter RFID systems....
This article presents the design and implementation of modular customizable event-driven architecture with parallel\r\nexecution capability for the first time with wireless sensor nodes using stand alone FPGA. This customizable\r\nevent-driven architecture is based on modular generic event dispatchers and autonomous event handlers, which will\r\nhelp WSN application developers to quickly develop their applications by adding the required number of event\r\ndispatchers and event handlers as per the need of a WSN application. This architecture can handle multiple events in\r\nparallel, including high priority ones. Additionally, it provides non-preemptive operation which removes the timing\r\nuncertainty and overhead involved with interrupt-driven processor-based sensor node implementation, which is\r\nrequired in real-time wireless sensor networks (WSNs). Thus, higher computation power of FPGAs combined with the\r\nnon-preemptive modular event-driven architecture with parallel execution capability enables a variety of new WSN\r\napplications and facilitates rapid prototyping of WSN applications. In this article, the performance of FPGA-based\r\nsensor device is compared with general purpose processor-based implementations of sensor devices. Results show\r\nthat our FPGA-based implementation provides significant improvement in system efficiency measured in terms of\r\nclock cycle counts required for typical sensor network tasks such as packet transmission, relay and reception....
Wireless sensor networks (WSNs), consisting of a large number of nodes to detect ambient environment, are widely\r\ndeployed in a predefined area to provide more sophisticated sensing, communication, and processing capabilities,\r\nespecially concerning the maintenance when hundreds or thousands of nodes are required to be deployed over wide\r\nareas at the same time. Radio frequency identification (RFID) technology, by reading the low-cost passive tags\r\ninstalled on objects or people, has been widely adopted in the tracing and tracking industry and can support an\r\naccurate positioning within a limited distance. Joint utilization of WSN and RFID technologies is attracting increasing\r\nattention within the Internet of Things (IoT) community, due to the potential of providing pervasive context-aware\r\napplications with advantages from both fields. WSN-RFID convergence is considered especially promising in\r\ncontext-aware systems with indoor positioning capabilities, where data from deployed WSN and RFID systems can be\r\nopportunistically exploited to refine and enhance the collected data with position information. In this papera, we\r\ndesign and evaluate a hybrid system which combines WSN and RFID technologies to provide an indoor positioning\r\nservice with the capability of feeding position information into a general-purpose IoT environment. Performance of\r\nthe proposed system is evaluated by means of simulations and a small-scale experimental set-up. The performed\r\nanalysis demonstrates that the joint use of heterogeneous technologies can increase the robustness and the accuracy\r\nof the indoor positioning systems....
Research and development of implantable RF telemetry systems intended specifically to enable and support cardiac\r\nmonitoring of genetically engineered small animal subjects, rats and mice in particular, has already gained significant\r\nmomentum. This article presents the state of the art review of experimental cardiac monitoring telemetry systems,\r\nwith strong accent on the systems designed to work with a dual pressureââ?¬â??volume conductance-based catheter\r\nsensor. These commercially available devices are already small enough to fit inside a left-ventricle of a mouse heart.\r\nHowever, if the complete system is to be fully implanted and the subject allowed to freely move inside a cage, the\r\nmouseââ?¬â?¢s small body size sets harsh constrains on the size and power consumption of the required electronics.\r\nConsequently, significant portion of the research efforts is directed towards the development of low-volume and\r\n-power electronics, as well as RF energy harvesting systems that are required to serve as the energy source to the\r\nimplanted telemetry instead of the relatively very bulky batteries....
Loading....