Effect of slot type identification on frame length optimization

In dense radio frequency identification (RFID) systems, reducing reading times is crucial. For tag anti-collision management, most RFID systems rely on frame slotted ALOHA (FSA). The most common method to reduce the reading time for large tag populations is optimization of the number of slots per frame. The slot duration in real RFID systems is determined by the slot type (idle, successful, or colliding). Furthermore, by detecting the strongest transponder, colliding slots can be transformed to successful slots, a phenomenon known as the capture effect. Additionally, RFID readers might be capable of identifying slot types using the physical layer which reduces the colliding slot time because at this moment the reader can immediately terminate the connection as there is no need to reply with invalid acknowledge and wait for the time-out. In this paper, we provide a novel approach for analytical estimation of the optimal frame length. Our approach yields a novel closed form equation for the frame length that takes into account durations of different slot types, the capture effect, and the probability of slot type identification. Experimental results for FM0 encoding show that our technique achieves a total reading time reduction between 5.5% and 11.3% over methods that do not take into account slot type identification. However, the reduction in reading time is maximally 9%, 6%, and 1% for Miller encoding scheme with M = 2, 4, and 8, respectively

Cancer Cells Treated by Clusters of Copper Oxide Doped Calcium Silicate

Purpose: Different compositions of copper oxide (CuO)-doped calcium silicate clusters wereused to treat the cancer cells.Methods: The influence of CuO content on the morphology, drug delivering ability,physicochemical properties and cytotoxicity was investigated.Results: The microcrystalline structure revealed the decrement of the size from (20-36 nm) to(5-7 nm) depending on the copper content percentages. Drug delivering ability of doxycyclinehyclate (Dox) was down regulated from 58% to 28%in the presence of the CuO. The inclusionof CuO and Dox didn’t show any remarkable changes on the physicochemical properties of theCuO-doped calcium silicate nanoparticles.Conclusion: The CuO-doped calcium silicate sample (5 weight %) exhibited great cytotoxicityagainst the tested cell lines compared to the CuO-free sample. CuO-doped materials displayedsignificant anticancer effect; this sheds light on its implication in the treatment of cancer

Biostratigraphic zonation of the Middle Eocene in the Nile Valley, based on larger Foraminifera

Volume: 20Start Page: 301End Page: 30

RFID reader and method for adjusting a frame length of an RFID system comprising an RFID reader

Embodiments provide an RFID reader. The RFID reader comprises a collision detector, a decoder and a frame length adjuster. The collision detector is configured to detect for each slot of a plurality of slots of a current frame, in which a collision of signals transmitted by at least two RFID tags occurred, a signal property of a signal of the signals transmitted by at least two RFID tags. The decoder is configured to decode for the slot in which the collision is detected the signal of the signals transmitted by the at least two RFID tags using the detected signal property, wherein a collision recover probability describing a probability that the decoder can accurately decode the one signal depends on a signal-to-noise ratio (SNR) of the current frame. The frame length adjuster is configured to adjust a frame length of a subsequent frame in dependence on the collision recover probability

RFID reader and method for recognizing RFID tags

The invention refers to an RFID reader (1) comprising a transmitter (2), a receiver (3), and an evaluator (4). The receiver (3) receives signals from RFID tags (10) within a given number of slots of a time frame with a given frame size (L) and provides a number of successful slots (ss) and a number of collided slots (cs). The evaluator (4) sets a modified frame size (L') based on an estimated number of RFID tags (n est ) which is determined based on the frame size (L), the number of successful slots (ss), and the number of collided slots (cs). The invention also refers to a corresponding method