204 research outputs found

    Perfect tag identification protocol in RFID networks

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    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

    Anti-collision techniques for RFID systems.

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    Chiang Kong Wa.Thesis (M.Phil.)--Chinese University of Hong Kong, 2006.Includes bibliographical references (leaves 74-79).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 2 --- Technology Overview --- p.4Chapter 2.1 --- Components of RFID Systems --- p.5Chapter 2.1.1 --- Tag --- p.6Chapter 2.1.2 --- Reader --- p.9Chapter 2.1.3 --- Software systems --- p.10Chapter 2.1.4 --- Communication infrastructure --- p.11Chapter 2.2 --- Frequency Regulations and Standards --- p.11Chapter 2.2.1 --- RFID frequency bands --- p.11Chapter 2.2.2 --- Standards --- p.12Chapter 2.3 --- Advantages and Limitations of RFID Technology --- p.14Chapter 2.4 --- Applications --- p.17Chapter 3 --- Background of Research --- p.20Chapter 3.1 --- Anti-collision methods for RFID systems --- p.22Chapter 3.1.1 --- Stochastic Anti-collision Protocols --- p.25Chapter 3.1.2 --- Deterministic Anti-collision Protocols --- p.27Chapter 4 --- Even-Odd Binary Tree Protocol --- p.30Chapter 4.1 --- Protocol Description --- p.31Chapter 4.2 --- Time Complexity Analysis --- p.34Chapter 4.3 --- Performance Evaluation --- p.37Chapter 4.4 --- Summary --- p.41Chapter 5 --- Prefix-Randomized Query-Tree Protocol --- p.44Chapter 5.1 --- Tag Identification - Known Tag Set Size --- p.45Chapter 5.1.1 --- Protocol Description --- p.45Chapter 5.1.2 --- Time Complexity Analysis --- p.47Chapter 5.1.3 --- Optimal Initial Prefix Length --- p.50Chapter 5.1.4 --- Optimal Number of Level-1 Nodes --- p.52Chapter 5.2 --- Tag Identification - Unknown Tag Set Size --- p.53Chapter 5.2.1 --- Initial Prefix Length Adaptation Algorithm --- p.54Chapter 5.2.2 --- Computing r*Δ(l) --- p.55Chapter 5.2.3 --- Optimal Choice of Step Size Δ --- p.56Chapter 5.3 --- Performance Evaluation --- p.59Chapter 5.4 --- Summary --- p.64Chapter 6 --- Conclusion and Future Work --- p.68Chapter 6.1 --- Conclusion --- p.68Chapter 6.2 --- Future Work --- p.70Bibliography --- p.7

    Tag anti-collision algorithms in RFID systems - a new trend

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    RFID is a wireless communication technology that provides automatic identification or tracking and data collection from any tagged object. Due to the shared communication channel between the reader and the tags during the identification process in RFID systems, many tags may communicate with the reader at the same time, which causes collisions. The problem of tag collision has to be addressed to have fast multiple tag identification process. There are two main approaches to the tag collision problem: ALOHA based algorithms and tree based algorithms. Although these methods reduce the collision and solve the problem to some extent, they are not fast and efficient enough in real applications. A new trend emerged recently which takes the advantages of both ALOHA and tree based approaches. This paper describes the process and performance of the tag anti-collision algorithms of the tree-ALOHA trend

    Building efficient wireless infrastructures for pervasive computing environments

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    Pervasive computing is an emerging concept that thoroughly brings computing devices and the consequent technology into people\u27s daily life and activities. Most of these computing devices are very small, sometimes even invisible , and often embedded into the objects surrounding people. In addition, these devices usually are not isolated, but networked with each other through wireless channels so that people can easily control and access them. In the architecture of pervasive computing systems, these small and networked computing devices form a wireless infrastructure layer to support various functionalities in the upper application layer.;In practical applications, the wireless infrastructure often plays a role of data provider in a query/reply model, i.e., applications issue a query requesting certain data and the underlying wireless infrastructure is responsible for replying to the query. This dissertation has focused on the most critical issue of efficiency in designing such a wireless infrastructure. In particular, our problem resides in two domains depending on different definitions of efficiency. The first definition is time efficiency, i.e., how quickly a query can be replied. Many applications, especially real-time applications, require prompt response to a query as the consequent operations may be affected by the prior delay. The second definition is energy efficiency which is extremely important for the pervasive computing devices powered by batteries. Above all, our design goal is to reply to a query from applications quickly and with low energy cost.;This dissertation has investigated two representative wireless infrastructures, sensor networks and RFID systems, both of which can serve applications with useful information about the environments. We have comprehensively explored various important and representative problems from both algorithmic and experimental perspectives including efficient network architecture design and efficient protocols for basic queries and complicated data mining queries. The major design challenges of achieving efficiency are the massive amount of data involved in a query and the extremely limited resources and capability each small device possesses. We have proposed novel and efficient solutions with intensive evaluation. Compared to the prior work, this dissertation has identified a few important new problems and the proposed solutions significantly improve the performance in terms of time efficiency and energy efficiency. Our work also provides referrable insights and appropriate methodology to other similar problems in the research community

    Influence of Managing the Number of Tag Bits Transmitted on the Query Tree RFID Collision Resolution Protocol

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    Radio Frequency Identification (RFID) technology is increasingly becoming popular, for its widespread use and more sophisticated applications. The coexistence of tags sharing the communication channel requires solutions to message collisions, which degrade bandwidth, and increase the number of transmitted bits. A new methodology called ‘window’ is presented to manage the number of bits transmitted by a tag. The aim is show how the query tree (QT) protocol is influenced by this feature, and how the performance of the novel protocol, query window tree (QwT), improves when the tag ID distribution is correlated. Therefore, we have performed a fair comparison of the Query Tree and the new proposed QwT protocol for various tag ID distributions. Simulations show that the QwT positively decreases the total number of bits that are transmitted by tags

    Towards Extended Bit Tracking for Scalable and Robust RFID Tag Identification Systems

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    The surge in demand for Internet of Things (IoT) systems and applications has motivated a paradigm shift in the development of viable radio frequency identification technology (RFID)-based solutions for ubiquitous real-Time monitoring and tracking. Bit tracking-based anti-collision algorithms have attracted considerable attention, recently, due to its positive impact on decreasing the identification time. We aim to extend bit tracking to work effectively over erroneous channels and scalable multi RFID readers systems. Towards this objective, we extend the bit tracking technique along two dimensions. First, we introduce and evaluate a type of bit errors that appears only in bit tracking-based anti-collision algorithms called false collided bit error in single reader RFID systems. A false collided bit error occurs when a reader perceives a bit sent by tag as an erroneous bit due to channel imperfection and not because of a physical collision. This phenomenon results in a significant increase in the identification delay. We introduce a novel, zero overhead algorithm called false collided bit error selective recovery tackling the error. There is a repetition gain in bit tracking-based anti-collision algorithms due to their nature, which can be utilized to detect and correct false collided bit errors without adding extra coding bits. Second, we extend bit tracking to 'error-free' scalable mutli-reader systems, while leaving the study of multi-readers tag identification over imperfect channels for future work. We propose the multi-reader RFID tag identification using bit tracking (MRTI-BT) algorithm which allows concurrent tag identification, by neighboring RFID readers, as opposed to time-consuming scheduling. MRTI-BT identifies tags exclusive to different RFIDs, concurrently. The concept of bit tracking and the proposed parallel identification property are leveraged to reduce the identification time compared to the state-of-The-Art. 2013 IEEE.This work was supported by the Qatar National Research Fund (a member of Qatar Foundation) through NPRP under Grant 7-684-1-127. The work of A. Fahim and T. ElBatt was supported by the Vodafone Egypt Foundation.Scopu

    Towards Secure and Scalable Tag Search approaches for Current and Next Generation RFID Systems

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    The technology behind Radio Frequency Identification (RFID) has been around for a while, but dropping tag prices and standardization efforts are finally facilitating the expansion of RFID systems. The massive adoption of this technology is taking us closer to the well known ubiquitous computing scenarios. However, the widespread deployment of RFID technology also gives rise to significant user security issues. One possible solution to these challenges is the use of secure authentication protocols to protect RFID communications. A natural extension of RFID authentication is RFID tag searching, where a reader needs to search for a particular RFID tag out of a large collection of tags. As the number of tags of the system increases, the ability to search for the tags is invaluable when the reader requires data from a few tags rather than all the tags of the system. Authenticating each tag one at a time until the desired tag is found is a time consuming process. Surprisingly, RFID search has not been widely addressed in the literature despite the availability of search capabilities in typical RFID tags. In this thesis, we examine the challenges of extending security and scalability issues to RFID tag search and suggest several solutions. This thesis aims to design RFID tag search protocols that ensure security and scalability using lightweight cryptographic primitives. We identify the security and performance requirements for RFID systems. We also point out and explain the major attacks that are typically launched against an RFID system. This thesis makes four main contributions. First, we propose a serverless (without a central server) and untraceable search protocol that is secure against major attacks we identified earlier. The unique feature of this protocol is that it provides security protection and searching capacity same as an RFID system with a central server. In addition, this approach is no more vulnerable to a single point-of-failure. Second, we propose a scalable tag search protocol that provides most of the identified security and performance features. The highly scalable feature of this protocol allows it to be deployed in large scale RFID systems. Third, we propose a hexagonal cell based distributed architecture for efficient RFID tag searching in an emergency evacuation system. Finally, we introduce tag monitoring as a new dimension of tag searching and propose a Slotted Aloha based scalable tag monitoring protocol for next generation WISP (Wireless Identification and Sensing Platform) tags

    Tag-collision resolution techniques for RFID systems.

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    Nie, Jing.Thesis (M.Phil.)--Chinese University of Hong Kong, 2007.Includes bibliographical references (leaves 73-77).Abstracts in English and Chinese.Abstract --- p.iAbstract (Chinese Version) --- p.iiiAcknowledgement --- p.ivChapter 1 --- Introduction --- p.1Chapter 2 --- Technology Overview --- p.4Chapter 2.1 --- History --- p.5Chapter 2.2 --- RFID Systems --- p.7Chapter 2.2.1 --- Tag --- p.8Chapter 2.2.2 --- Reader --- p.10Chapter 2.2.3 --- Software system --- p.12Chapter 2.2.4 --- Communication infrastructure --- p.13Chapter 2.3 --- Frequency Regulations and Standards --- p.13Chapter 2.3.1 --- RFID frequency --- p.13Chapter 2.3.2 --- Standards --- p.14Chapter 2.4 --- Technology Comparison and RFID Applications --- p.16Chapter 2.4.1 --- Technology Comparison --- p.16Chapter 2.4.2 --- RFID Applications --- p.19Chapter 3 --- Research Background --- p.22Chapter 3.1 --- Tag-Collision Resolution Techniques for RFID systems --- p.23Chapter 3.1.1 --- Deterministic Collision-Resolution Technique --- p.25Chapter 3.1.2 --- Stochastic Collision-Resolution Technique --- p.27Chapter 4 --- Optimized Anti-Collision Protocol --- p.30Chapter 4.1 --- System Description --- p.31Chapter 4.2 --- Mathematical System Model --- p.35Chapter 4.3 --- Optimal Parameter --- p.40Chapter 4.3.1 --- Stochastic Shortest Path --- p.41Chapter 4.3.2 --- Optimal Parameter --- p.44Chapter 4.4 --- Performance Evaluation --- p.45Chapter 4.4.1 --- Initial and Optimal Policy --- p.45Chapter 4.4.2 --- Performance Comparison --- p.48Chapter 4.5 --- Summary --- p.53Chapter 5 --- Unknown Tag Set Anti-Collision Protocol --- p.54Chapter 5.1 --- Protocol Description --- p.55Chapter 5.1.1 --- System Model --- p.55Chapter 5.1.2 --- Tag Estimation --- p.57Chapter 5.2 --- Performance Evaluation --- p.62Chapter 5.3 --- Summary --- p.67Chapter 6 --- Conclusion and Future Work --- p.68Chapter 6.1 --- Conclusion --- p.68Chapter 6.2 --- Future Work --- p.70Bibliography --- p.7
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