399 research outputs found
Reliable Identification of RFID Tags Using Multiple Independent Reader Sessions
Radio Frequency Identification (RFID) systems are gaining momentum in various
applications of logistics, inventory, etc. A generic problem in such systems is
to ensure that the RFID readers can reliably read a set of RFID tags, such that
the probability of missing tags stays below an acceptable value. A tag may be
missing (left unread) due to errors in the communication link towards the
reader e.g. due to obstacles in the radio path. The present paper proposes
techniques that use multiple reader sessions, during which the system of
readers obtains a running estimate of the probability to have at least one tag
missing. Based on such an estimate, it is decided whether an additional reader
session is required. Two methods are proposed, they rely on the statistical
independence of the tag reading errors across different reader sessions, which
is a plausible assumption when e.g. each reader session is executed on
different readers. The first method uses statistical relationships that are
valid when the reader sessions are independent. The second method is obtained
by modifying an existing capture-recapture estimator. The results show that,
when the reader sessions are independent, the proposed mechanisms provide a
good approximation to the probability of missing tags, such that the number of
reader sessions made, meets the target specification. If the assumption of
independence is violated, the estimators are still useful, but they should be
corrected by a margin of additional reader sessions to ensure that the target
probability of missing tags is met.Comment: Presented at IEEE RFID 2009 Conferenc
Perfect tag identification protocol in RFID networks
Radio Frequency IDentification (RFID) systems are becoming more and more
popular in the field of ubiquitous computing, in particular for objects
identification. An RFID system is composed by one or more readers and a number
of tags. One of the main issues in an RFID network is the fast and reliable
identification of all tags in the reader range. The reader issues some queries,
and tags properly answer. Then, the reader must identify the tags from such
answers. This is crucial for most applications. Since the transmission medium
is shared, the typical problem to be faced is a MAC-like one, i.e. to avoid or
limit the number of tags transmission collisions. We propose a protocol which,
under some assumptions about transmission techniques, always achieves a 100%
perfomance. It is based on a proper recursive splitting of the concurrent tags
sets, until all tags have been identified. The other approaches present in
literature have performances of about 42% in the average at most. The
counterpart is a more sophisticated hardware to be deployed in the manufacture
of low cost tags.Comment: 12 pages, 1 figur
Distributed Wireless Algorithms for RFID Systems: Grouping Proofs and Cardinality Estimation
The breadth and depth of the use of Radio Frequency Identification (RFID) are becoming more substantial. RFID is a technology useful for identifying unique items through radio waves. We design algorithms on RFID-based systems for the Grouping Proof and Cardinality Estimation problems.
A grouping-proof protocol is evidence that a reader simultaneously scanned the RFID tags in a group. In many practical scenarios, grouping-proofs greatly expand the potential of RFID-based systems such as supply chain applications, simultaneous scanning of multiple forms of IDs in banks or airports, and government paperwork. The design of RFID grouping-proofs that provide optimal security, privacy, and efficiency is largely an open area, with challenging problems including robust privacy mechanisms, addressing completeness and incompleteness (missing tags), and allowing dynamic groups definitions. In this work we present three variations of grouping-proof protocols that implement our mechanisms to overcome these challenges.
Cardinality estimation is for the reader to determine the number of tags in its communication range. Speed and accuracy are important goals. Many practical applications need an accurate and anonymous estimation of the number of tagged objects. Examples include intelligent transportation and stadium management. We provide an optimal estimation algorithm template for cardinality estimation that works for a {0,1,e} channel, which extends to most estimators and ,possibly, a high resolution {0,1,...,k-1,e} channel
Energy efficient tag identification algorithms for RFID: survey, motivation and new design
RFID is widely applied in massive tag based applications, thus effective anti-collision algorithms to reduce communication overhead are of great importance to RFID in achieving energy and time efficiency. Existing MAC algorithms are primarily focusing on improving system throughput or reducing total identification time. However, with the advancement of embedded systems and mobile applications, the energy consumption aspect is increasingly important and should be considered in the new design. In this article, we start with a comprehensive review and analysis of the state-of-the-art anti-collision algorithms. Based on our existing works, we further discuss a novel design of anti-collision algorithm and show its effectiveness in achieving energy efficiency for the RFID system using EPCglobal C1 Gen2 UHF standard
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