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18
Fast Tag Searching Protocol for Large-Scale RFID Systems
"... Abstract—Fast searching a particular subset in a large number of products attached with RFID tags is of practical importance for a variety of applications but not yet thoroughly investigated. Since the cardinality of the products can be extremely large, collecting the tag information directly from e ..."
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Abstract—Fast searching a particular subset in a large number of products attached with RFID tags is of practical importance for a variety of applications but not yet thoroughly investigated. Since the cardinality of the products can be extremely large, collecting the tag information directly from each of those tags could be highly inefficient. To address the tag searching efficiency in large-scale RFID systems, this paper proposes several algorithms to meet the stringent delay requirement in developing fast tag searching protocols. We formally formulate the tag searching problem in large-scale RFID systems. We propose utilizing compact approximators to efficiently aggregate a large volume of RFID tag information and exchange such information with a two-phase approximation protocol. By estimating the intersection of two compact approximators, the proposed twophase compact approximator based tag searching protocol significantly reduces the searching time compared with all possible solutions we can directly borrow from existing studies. We further introduce a scalable cardinality range estimation method which provides inexpensive input for our tag searching protocol. We conduct comprehensive simulations to validate our design. The results demonstrate that the proposed tag searching protocol is highly efficient in terms of both time-efficiency and transmission overhead, leading to good applicability and scalability for largescale RFID systems.
Tagoram: Real-Time Tracking of Mobile RFID Tags to High Precision Using COTS Devices
"... In many applications, we have to identify an object and then locate the object to within high precision (centimeter- or millimeter-level). Legacy systems that can provide such accuracy are either expensive or suffering from performance degradation resulting from various impacts, e.g., occlusion for ..."
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In many applications, we have to identify an object and then locate the object to within high precision (centimeter- or millimeter-level). Legacy systems that can provide such accuracy are either expensive or suffering from performance degradation resulting from various impacts, e.g., occlusion for computer vision based approaches. In this work, we present an RFID-based system, Tagoram, for object localization and tracking using COTS RFID tags and readers. Tracking mobile RFID tags in real time has been a daunting task, especially challenging for achieving high precision. Our system achieves these three goals by leveraging the phase value of the backscattered signal, provided by the COTS RFID readers, to estimate the location of the object. In Tagoram, we exploit the tag’s mobility to build a virtual antenna array by using readings from a few physical antennas over a time window. To illustrate the basic
Read bulk data from computational rfids
- In Proc. of IEEE INFOCOM
, 2014
"... Abstract—Without the need of local energy supply, computa-tional RFID (CRFID) sensors are emerging as important plat-forms enabling a variety of sensing and computing applications. Nevertheless, the data throughput of CRFIDs is very low. This paper aims at efficiently transferring bulk data from CRF ..."
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Abstract—Without the need of local energy supply, computa-tional RFID (CRFID) sensors are emerging as important plat-forms enabling a variety of sensing and computing applications. Nevertheless, the data throughput of CRFIDs is very low. This paper aims at efficiently transferring bulk data from CRFIDs to commodity RFID readers. We first investigate the problem of low data throughput of CRFIDs. We then propose several simple yet effective techniques to allow CRFIDs to meet stringent timing requirement of commodity RFID readers and achieve efficient data transfer. We implement a prototype system based on the WISP CRFIDs and commercial off-the-self RFID reader. The experiment results show that our approach provides better compatibility with EPCglobal C1G2 compliant RFID devices and works perfectly with the commodity RFID readers. I.
A Parallel Identification Protocol for RFID Systems
"... Abstract—Nowadays, RFID systems have been widely deployed for applications such as supply chain management and inventory control. One of their most essential operations is to swiftly identify individual tags to distinguish their associated objects. Most existing solutions identify tags sequentially ..."
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Abstract—Nowadays, RFID systems have been widely deployed for applications such as supply chain management and inventory control. One of their most essential operations is to swiftly identify individual tags to distinguish their associated objects. Most existing solutions identify tags sequentially in the temporal dimension to avoid signal collisions, whose performance degrades significantly as the system scale increases. In this paper, we propose a Parallel Identification Protocol (PIP) for RFID systems, which achieves the parallel identification paradigm and is com-patible with current RFID devices. Uniquely, PIP encodes the tag ID intoa specially designed patternand thus greatly facilitates the reader to correctly and effectively recover them from collisions. Furthermore, we analytically investigate its performance and provide guidance on determining its optimal settings. Extensive simulation shows that PIP reduces the identification delay by about 25% 50 % when compared with the standard method in EPC C1G2 and the state-of-the-art solutions. I.
Precise Power Delay Profiling with Commodity WiFi
"... Power delay profiles characterize multipath channel features, which are widely used in motion- or localization-based applications. Re-cent studies show that the power delay profile may be derived from the CSI traces collected from commodity WiFi devices, but the performance is limited by two dominat ..."
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Power delay profiles characterize multipath channel features, which are widely used in motion- or localization-based applications. Re-cent studies show that the power delay profile may be derived from the CSI traces collected from commodity WiFi devices, but the performance is limited by two dominating factors. The resolution of the derived power delay profile is determined by the channel bandwidth, which is however limited on commodity WiFi. The collected CSI reflects the signal distortions due to both the chan-nel attenuation and the hardware imperfection. A direct deriva-tion of power delay profiles using raw CSI measures, as has been done in the literature, results in significant inaccuracy. In this pa-per, we present Splicer, a software-based system that derives high-resolution power delay profiles by splicing the CSI measurements from multiple WiFi frequency bands. We propose a set of key tech-niques to separate the mixed hardware errors from the collected CSI measurements. Splicer adapts its computations within strin-gent channel coherence time and thus can perform well in presence of mobility. Our experiments with commodity WiFi NICs show that Splicer substantially improves the accuracy in profiling multi-path characteristics, reducing the errors of multipath distance esti-mation to be less than 2m. Splicer can immediately benefit upper-layer applications. Our case study with recent single-AP localiza-tion achieves a median localization error of 0.95m.
See Through Walls with COTS RFID System!
"... Through-wall tracking has gained a lot of attentions in civilian ap-plications recently. Many applications would benefit from such device-free tracking, e.g. elderly people surveillance, intruder de-tection, gaming, etc. In this work, we present a system, named Tadar, for tracking moving objects wit ..."
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Through-wall tracking has gained a lot of attentions in civilian ap-plications recently. Many applications would benefit from such device-free tracking, e.g. elderly people surveillance, intruder de-tection, gaming, etc. In this work, we present a system, named Tadar, for tracking moving objects without instrumenting them us-ing COTS RFID readers and tags. It works even through walls and behind closed doors. It aims to enable a see-through-wall technol-ogy that is low-cost, compact, and accessible to civilian purpose. In traditional RFID systems, tags modulate their IDs on the backscat-ter signals, which is vulnerable to the interferences from the am-bient reflections. Unlike past work, which considers such vulner-ability as detrimental, our design exploits it to detect surrounding objects even through walls. Specifically, we attach a group of RFID tags on the outer wall and logically convert them into an antenna array, receiving the signals reflected off moving objects. This paper introduces two main innovations. First, it shows how to eliminate the flash (e.g. the stronger reflections off walls) and extract the reflections from the backscatter signals. Second, it shows how to track the moving object based on HMM (Hidden Markov Model) and its reflections. To the best of our knowledge, we are the first to implement a through-wall tracking using the COTS RFID sys-tems. Empirical measurements with a prototype show that Tadar can detect objects behind 5′ ′ hollow wall and 8′ ′ concrete wall, and achieve median tracking errors of 7.8cm and 20cm in the X and Y dimensions. 1.
978-1-4799-3360-0/14/$31.00 c©2014 IEEE A Parallel Identification Protocol for RFID Systems
"... Abstract—Nowadays, RFID systems have been widely deployed for applications such as supply chain management and inventory control. One of their most essential operations is to swiftly identify individual tags to distinguish their associated objects. Most existing solutions identify tags sequentially ..."
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Abstract—Nowadays, RFID systems have been widely deployed for applications such as supply chain management and inventory control. One of their most essential operations is to swiftly identify individual tags to distinguish their associated objects. Most existing solutions identify tags sequentially in the temporal dimension to avoid signal collisions, whose performance degrades significantly as the system scale increases. In this paper, we propose a Parallel Identification Protocol (PIP) for RFID systems, which achieves the parallel identification paradigm and is com-patible with current RFID devices. Uniquely, PIP encodes the tag ID into a specially designed pattern and thus greatly facilitates the reader to correctly and effectively recover them from collisions. Furthermore, we analytically investigate its performance and provide guidance on determining its optimal settings. Extensive simulations show that PIP reduces the identification delay by about 25% − 50 % when compared with the standard method in EPC C1G2 and the state-of-the-art solutions. I.
10.1109/TPDS.2014.2357021, IEEE Transactions on Parallel and Distributed Systems 1 Efficient Protocols for Collecting Histograms in Large-scale RFID Systems
"... Abstract—Collecting histograms over RFID tags is an essential premise for effective aggregate queries and analysis in large-scale RFID-based applications. In this paper we consider an efficient collection of histograms from the massive number of RFID tags, without the need to read all tag data. In o ..."
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Abstract—Collecting histograms over RFID tags is an essential premise for effective aggregate queries and analysis in large-scale RFID-based applications. In this paper we consider an efficient collection of histograms from the massive number of RFID tags, without the need to read all tag data. In order to achieve time efficiency, we propose a novel, ensemble sampling-based method to simultaneously estimate the tag size for a number of categories. We first consider the problem of basic histogram collection, and propose an efficient algorithm based on the idea of ensemble sampling. We further consider the problems of advanced histogram collection, respectively, with an iceberg query and a top-k query. Efficient algorithms are proposed to tackle the above problems such that the qualified/unqualified categories can be quickly identified. This ensemble sampling-based framework is very flexible and compatible to current tag-counting estimators, which can be efficiently leveraged to estimate the tag size for each category. Experiment results indicate that our ensemble sampling-based solutions can achieve a much better performance than the basic estimation/identification schemes.
IEEE COMMUNICATIONS SURVEYS & TUTORIALS, ACCEPTED FOR PUBLICATION 1 Managing RFID Data: Challenges, Opportunities and Solutions
"... (RFID) technology have significantly enhanced the capability of capturing data from pervasive space. It becomes a great challenge in the information era to effectively understand human behavior, mobility and activity through the perceived RFID data. Focusing on RFID data management, this article pro ..."
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(RFID) technology have significantly enhanced the capability of capturing data from pervasive space. It becomes a great challenge in the information era to effectively understand human behavior, mobility and activity through the perceived RFID data. Focusing on RFID data management, this article provides an overview of current challenges, emerging opportunities and recent progresses in RFID. In particular, this article has described and analyzed the research work on three aspects: algorithm, protocol and performance evaluation. We investigate the research progress in RFID with anti-collision algorithms, authentication and privacy protection protocols, localization and activity sensing, as well as performance tuning in realistic settings. We emphasize the basic principles of RFID data management to understand the state-of-the-art and to address directions of future research in RFID. Index Terms—RFID, data management, anti-collision algo-rithms, authentication and privacy protection, localization and activity sensing, performance evaluation. I.
Efficient Protocols for Collecting Histograms in Large-Scale RFID Systems
"... Abstract—Collecting histograms over RFID tags is an essential premise for effective aggregate queries and analysis in large-scale RFID-based applications. In this paper we consider an efficient collection of histograms from the massive number of RFID tags, without the need to read all tag data. In o ..."
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Abstract—Collecting histograms over RFID tags is an essential premise for effective aggregate queries and analysis in large-scale RFID-based applications. In this paper we consider an efficient collection of histograms from the massive number of RFID tags, without the need to read all tag data. In order to achieve time efficiency, we propose a novel, ensemble sampling-based method to simultaneously estimate the tag size for a number of categories. We first consider the problem of basic histogram collection, and propose an efficient algorithm based on the idea of ensemble sampling. We further consider the problems of advanced histogram collection, respectively, with an iceberg query and a top-k query. Efficient algorithms are proposed to tackle the above problems such that the qualified/unqualified categories can be quickly identified. This ensemble sampling-based framework is very flexible and compatible to current tag-counting estimators, which can be efficiently leveraged to estimate the tag size for each category. Experiment results indicate that our ensemble sampling-based solutions can achieve a much better performance than the basic estimation/identification schemes. Index Terms—Algorithms, RFID, time efficiency, histogram Ç
