Radio Frequency Identification Fundamentals and Applications, Bringing Research to Practice Radio Frequency Identification Fundamentals and Applications, Bringing Research to Practice Edited by Cristina Turcu Intech IV Published by Intech Intech Olajnica 19/2, 32000 Vukovar, Croatia Abstracting and non-profit use of the material is permitted with credit to the source Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher No responsibility is accepted for the accuracy of information contained in the published articles Publisher assumes no responsibility liability for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained inside After this work has been published by the Intech, authors have the right to republish it, in whole or part, in any publication of which they are an author or editor, and the make other personal use of the work © 2010 Intech Free online edition of this book you can find under www.sciyo.com Additional copies can be obtained from: publication@sciyo.com First published February 2010 Printed in India Technical Editor: Teodora Smiljanic Cover designed by Dino Smrekar Radio Frequency Identification Fundamentals and Applications, Bringing Research to Practice, Edited by Cristina Turcu p cm ISBN 978-953-7619-73-2 Preface This book, entitled Radio Frequency Identification Fundamentals and Applications, Bringing Research to Practice, bridges the gap between theory and practice and brings together a variety of research results and practical solutions in the field of RFID The book is a rich collection of articles written by people from all over the world: teachers, researchers, engineers, and technical people with strong background in the RFID area Developed as a source of information on RFID technology, the book addresses a wide audience including designers for RFID systems, researchers, students and any person who would like to learn about this field The first chapter of this book analyzes an algorithm for interrogation zone estimation in inductive coupled anti-collision RFID identification systems The field aspects of operation conditions are taken into consideration Chapter presents an overview of the RFID identification process and focuses on how RFID systems work in static and dynamic scenarios, collisions in the Medium Access Control (MAC) layer, the more relevant and adopted EPCglobal specifications and the performance analysis of the identification process In chapter the author reviews several approaches in solving passive RFID tag collision problems Chapter addresses two important issues related to RFID system: electronic and MAC protocol characterization to avoid reader-reader and reader-tag collisions in a dense RFID network Chapter aims to analyze the MAC technologies adopted in RFID, considering both deterministic and stochastic MAC protocols for RFID systems proposed in standards, specifications and recent literature Their principles are described and their performance is assessed and compared through theoretical and numerical arguments Chapter is dedicated to stochastic model and performance analysis of RFID The chapter comprises reviews of the frame slotted ALOHA based tag anti-collision protocols Also, the authors investigated a stochastic model for RFID tag collision resolution Various methods proposed for the estimation of RFID tag population within the vicinity of the RFID reader are examined and evaluated Chapter presents an overview of several RFID anti-collision algorithms and proposes an improved dynamic framed slotted ALOHA algorithm for a large number of tags VI Chapter briefly reviews already existing RFID systems and provides an in-depth analysis of a commercial development system The authors present a speed measurement application using the same RFID system and important EMC information regarding the use of high frequency RFID system In chapter the authors propose an IP-based RFID architecture that allows low cost and large scale deployment, as well as an easy integration with IP-based services Chapter 10 presents the fundamentals of object tracking and focuses on one special technique to develop an RFID network and the ways in which tagged objects can be tracked in such a network Chapter 11 deals with the designing and verifying the secure authentication protocol, which is widely researched in RFID systems using formal methods Thus, the RFID security requirements in home network environments are defined, and an authentication mechanism among reader, tag and database is proposed The authors of chapter 12 propose an RFID tag system that includes an interrogator with an algorithm that generates RFID passwords to protect both the RFID data and consumer privacy In chapter 13 the authors describe an authentication mechanism based on the COMP128 algorithm to be used in mobile RFID environments Chapter 14 offers an introduction to RFID systems, summarizes several concepts of RFID system integration, and introduces some integration examples of RFID applications Chapter 15 focuses on major short and long-term benefits of RFID systems and advices on efficient RFID technology integration Chapter 16 explores fundamentals of data management in RFID applications so that the data retrieved out of RFID applications is non-redundant and filtered Chapter 17 discusses different design possibilities for data storage in RFID systems and their impact on the quality factors of the resulting system In the final chapter of this book the authors introduce the widely applied RFID middlewares with the technique of Web services and propose a Context store approach to improve the performance of data transmission between a mobile client and a Web services server At this point I would like to express my thanks to all scientists who were kind enough to contribute to the success of this project by presenting numerous technical studies and research results But, we couldn’t have published this book without InTech team’s effort I wish to extend my most sincere gratitude to the InTech publishing house for continuing to publish new, interesting and valuable books for all of us Editor Cristina TURCU Department of Computer Science Stefan cel Mare University of Suceava Romania Contents Preface Field Conditions of Interrogation Zone in Anticollision Radio Frequency Identification Systems with Inductive Coupling V 001 Piotr Jankowski-Mihułowicz Characterization of the Identification Process in RFID Systems 027 J Vales-Alonso, M.V Bueno-Delgado, E Egea-López, J.J Alcaraz-Espín and F.J González-Casto The Approaches in Solving Passive RFID Tag Collision Problems 049 Hsin-Chin Liu Electronic and Mac Protocol Characterization of RFID Modules 057 Nasri Nejah, Kachouri Abdennaceur, Andrieux Laurent and Samet Mounir MAC Protocols for RFID Systems 073 Marco Baldi and Ennio Gambi Stochastical Model and Performance Analysis of Frequency Radio Identification 087 Yan Xinqing, Yin Zhouping and Xiong Youlun Anti-collision Algorithms for Multi-Tag RFID 103 GENG Shu-qin, WU Wu-chen, HOU Li-gang and ZHANG Wang Applications of RFID Systems - Localization and Speed Measurement 113 Valentin Popa, Eugen Coca and Mihai Dimian IP-based RFID Location System Phuoc Nguyen Tran and Nadia Boukhatem 131 VIII 10 Tracking Methodologies in RFID Network 145 M Ayoub Khan 11 The Modeling and Analysis of the Strong Authentication Protocol for Secure RFID System 157 Hyun-Seok Kim and Jin-Young Choi 12 Evaluation of Group Management of RFID Passwords for Privacy Protection 171 Yuichi Kobayashi, Toshiyuki Kuwana, Yoji Taniguchi and Norihisa Komoda 13 A Mobile RFID Authentication Scheme Based on the COMP-128 Algorithm 183 Jia-Ning Luo and Ming Hour Yang 14 RFID System Integration and Application Examples 197 Ming-Shen Jian 15 RFID System Integration 211 Hamid Jabbar and Taikyeong Ted Jeong 16 RFID Data Management 229 Sapna Tyagi, M Ayoub Khan and A Q Ansari 17 Data Storage in RFID Systems 251 Dirk Henrici, Aneta Kabzeva, Tino Fleuren and Paul Müller 18 An Efficient Approach for Data Transmission in RFID Middleware Hongying LIU, Satoshi GOTO and Junhuai LI 267 Field Conditions of Interrogation Zone in Anticollision Radio Frequency Identification Systems with Inductive Coupling Piotr Jankowski-Mihułowicz Rzeszów University of Technology Poland Introduction Passive Radio Frequency IDentification (RFID) systems with inductive coupling are the most widespread nowadays (Yan et al., 2008; Wolfram et al., 2008) These systems operate thanks to direct inductive coupling between antenna units of the communication system which consist of Read/Write Device (RWD) and electronic identifier (called a tag or transponder) The communication in transmitter – receiver set is carried out in two ways In the first case, only one object with electronic tag can be placed in the correct working area called interrogation zone of the RFID system This arrangement is called a single identification system or also single system In the second case of multiple identification system, called anticollision system, the communication process is carried out simultaneously with multiple RFID tags In this process, the algorithms of multi-access to the radio channel are used, what provides an effective way to distinguish simultaneously between multiple objects (Yeh et al., 2009; Dobkin & Wandinger, 2005) It should be note that synthesis procedure of interrogation zone includes the simultaneous analysis of electromagnetic field (presented in this paper), communication protocols and electric aspects of operation conditions in the process of system efficiency identification The typical applications of anticollision RFID systems are concentrated on different economic and public activity in industry, commerce, science, medicine and others (Harrison, 2009, Donaljdson, 2009; Steden, 2005; Wyld, 2009 and 2005; Åhlström, 2005) When determining the interrogation zone for the given automatic identification process, it is necessary to define a maximum working distance of the RFID system This parameter determines the distance between the specified point of the RWD’s and the midpoint of the tag’s antenna loop It is very important because the magnetic field generated around the RWD’s antenna loop is not only medium of information signal but also provides passive tags with energy The proper supply is essential to carry out operations of recording and reading information which is stored in the transponder’s semiconductor memory (Fig 1) The basic parameter, which determines the working area and characterizes the maximum working distance of the RFID system, is Hmin minimum value of magnetic field strength or more often used Bmin minimum value of magnetic induction at which the correct data transmission between the RWD and the tag takes place (Jankowski-M & Kalita, 2008) The minimum value of magnetic induction required in the process of writing data to the Radio Frequency Identification Fundamentals and Applications, Bringing Research to Practice internal memory of tag (BminWrite) is several percent larger than the value of this parameter in the process of reading (BminRead) So the operation mode of the internal memory affects occurrence of changes in the interrogation zone There is decreasing the maximum distance in writing mode in comparison to reading process During the analysis of field conditions in RFID system the general case will be considered and represented by notation Bmin Real Fast Moving Consumer Goods (FMCG) example INTERROGATION ZONE OF ANTICOLLISION RFID SYSTEM PROBLEM OF REALIZATION OF ANTICOLLISION AUTOMATIC IDENTIFICATION PROCESS RF identification ΩID ID EN TI FI CA TI O N RF identification Industrial application (pallet with products ) Anticollision RFID System LACK O F ID ENTI FICATIO N Simultaneous identification of many objects A T IO N What identified ? INTERROGATION ZONE OF ANTICOLLISION RFID SYSTEM WITH INDUCTIVE COUPLING TI FI C ΩID Tag n antenna unit (critical constant: Bmin) B ID EN K OF LAC CATION TIFI IDEN RF identification (x n,yn,z n) (x 2,y2,z2) TAG CIRCUIT (CHIP) TAG ANTENNA CIRCUIT TAG n ANTENNA LOOP TAG ANTENNA LOOP TAG n ANTENNA CIRCUIT TAG n CIRCUIT (CHIP) Mn M2 TAG ANTENNA LOOP DATA ENERGY z RWD ANTENNA CIRCUIT y x IR (critical constant: ΔφRmax) ZR TAG CIRCUIT (CHIP) M1 2) Maximum change of the impedance ZR under influence of the tags is expressed by maximum value of difference of impedance’s arguments Δφ Rmax without the tags and with them, respectively RWD Read /Write Device TAG ANTENNA CIRCUIT RWD ANTENNA LOOP RWD antenna unit Fig Block diagram of anticollision RFID system with inductive coupling and illustration of practical automatic RFID process Antenna unit array: RWD-TAGS (x,y,z) 3D coordinates B magnetic induction current of RWD antenna loop IR M mutual inductance n number of tags CRITICAL CONSTANTS : 1) Minimal value of energy is determined by minimal value of magnetic induction Bmin in each point of its location (x1,y1,z 1) Field Conditions of Interrogation Zone in Anticollision Radio Frequency Identification Systems with Inductive Coupling The Bmin value, which is considered individually for each transponder in a magnetic field of RWD loop (ΩID area – Fig 1), depends on the structure and parameters of this loop but also of tag antenna In the case of multiple identification process, it is necessary to provide all tags placed within the interrogation zone of RWD antenna with proper power For this geometric configuration, the parameters of magnetically coupled transponders affect significantly the total loop impedance of RWD antenna and cause big changes in many parameters of its electrical circuit In consequence, this phenomenon leads to disruption in communication with the tags which are placed within the working area but close to boundary points where the magnetic induction has the minimal value The correct analysis of the total impedance in coupled system (consisted of RWD and tags antenna loops), and thereby analysis of changes in the magnetic field in the considered interrogation zone, allows to estimate the proper boundary of area with spatial placed multiple tags for the case of designing anticollision RFID system with inductive coupling The operating range of RFID systems with inductive coupling In terms of emission of electromagnetic field, the RFID systems are placed in a group of radio equipment devices and they use allocated band in respective frequency range (Fig 2) ETSI EN 300 330 -1 V1.5.1:2006 Electromagnetic compatibility and Radio spectrum Matters (ERM); Short Range Devices (SRD); Radio equipment in the frequency range kHz to 25 MHz and inductive loop systems in the frequency range kHz to 30 MHz; Part 1: Technical characteristics and test methods Magnetic field strength , H, dBµA/m (10 m from the radiation source, for frequency f < 30 MHz) 80 Radio Frequency IDentification systems with inductive coupling 100-135 kHz 60 Wave propagation RFID systems that operates at UHF and microwave bands: 13,56 MHz - 865-868 MHz up to W ERP (ETSI EN 302 208 , ETSI EN 300 220 ), 40 - 2446-2454 MHz up to 500 mW EIRP (ETSI EN 300 440 ) 20 Frequency f, MHz: 0.1 10 100 1000 Wavelength λ, m: 3000 300 30 0.3 0.03 Frequency range : LF MF HF VHF UHF SHF 10000 Fig Frequency ranges and European licensing regulation for RFID systems Frequency bands widely available for different kind of radio systems (called ISM Industrial-Scientific-Medical) are used in contact-less identification of objects (ERC, 2008) Therefore, it is required to reduce the magnetic field strength produced by a transmitting antenna of low frequency systems, and reduce the effective radiated power for systems operating in the range of ultra-short waves and microwaves 4 Radio Frequency Identification Fundamentals and Applications, Bringing Research to Practice Contact-less inductively coupled systems are used to identify objects in the range of the lowest frequencies (in the wave ranges from medium to short) These systems are currently the most widespread, developed and supported by all the key suppliers of RFID components (Yan et al., 2008) They are characterized by working in the area where a strong magnetic coupling between antennas of transmitting components occurs and also where there is strong wave mismatching between communication equipments (Flores et al., 2005) Assuming that the wave propagates in a vacuum, the phase coefficient β takes the real value: β = ω μ 0ε (1) where ω denotes the pulsation, μ0 – magnetic permeability of vacuum whereas ε0 means electric permittivity of vacuum With respect to the classical theory of antennas, it is possible to specify the working distance of inductively coupled RFID systems according to the following conditions (Fig 3): • for an induction zone - near field (all systems with inductive coupling): z (3) with signs appearing in the dependencies (2) and (3) described in Fig Frequency Region defined by the antenna theory 100 – 135 kHz 13.56 MHz Near field (near zone ), z 1, β – phase constant Region defined for the RFID technology RFID near field (RFID near zone) RFID far field (RFID far zone) functioning range approximately up to a dozen cm; proximity range RFID systems functioning range up to approximately a few dozen cm (LF) or a few meter (HF); long range RFID systems Industry , Science, Medicine (ISM) Example applications For memory tags in particular : logistics access control work time registration animal identification etc For memory and microchip tags : automatic charging bank cards parking cards etc Fig Operating region of RFID systems with inductive coupling The average distance between the transmitter and the receiver is from a few centimetres to several meters in the case of RFID systems operating in the range of short-wave For such a separated working area, the value of the energy flux density transmitted by an Field Conditions of Interrogation Zone in Anticollision Radio Frequency Identification Systems with Inductive Coupling electromagnetic wave (Poynting vector) is zero This means that the functional principle of RFID systems with inductive coupling is primarily storage of energy in the magnetic field Examples of working distances, detailed specified ranges and operating limit of two inductively coupled RFID systems are shown in Fig Magnetic field strength H, dBµA/m 150 125 kHz 13.56 MHz 100 Example limits of functioning of long range RFID systems 50 Near field (near zone) Fresnel zone 13.56 MHz RFID near field (RFID near zone) – RFID far field (RFID far zone) – proximity range RFID systems long range RFID systems 125 kHz 50 0.01 Near field (near zone) 0.1 3.519 10 Distance from the center on axis of symmetry of RWD antenna loop 100 z, m Fig Magnetic field strength for the transmitting antennas operating at the frequency of 125 kHz and 13.56 MHz with a specification of the working scope according to the classical theory of antennas and for RFID systems with inductive coupling With regard to the established characteristic of working distance in RFID systems, the two working scopes are defined The RFID near field which means the operating distance up to about a dozen centimetres and the RFID far field where the operating range is around from few dozen centimetres to several meters (Bhatt & Glover, 2006; Finkenzeller, 2003; Paret, 2005) It should be noted that these limits, for both the classical theory of antennas as well as RFID systems, are not distances at which rapid changes in transmission parameters occur Both the changes in properties of the electromagnetic field (zero or nonzero value of the Poynting vector) as well as changes in the efficiency of interaction between communication equipments (which differ in structures depending on a range for RFID near-and far field) have continuous character at estimated boundaries Restrictions on the magnetic field strength in RFID systems with inductive coupling The issue of radio system operation is connected with electromagnetic radiation With regard to the operation correctness and proper construction of RFID system it is necessary to recognise harmful effects of electromagnetic field on the human body and to determine acceptable radiation standards (EN 50364, 2001; EN 50357, 2001; IEC 62369, 2008) In the field of RFID systems with inductive coupling the restrictions of the magnetic field strength are contained in ETSI EN 300 330 standard (ETSI, 2006), which is based on CEPT/ERC Recommendation 70-03 document (ERC, 2008) This document was prepared by the European Telecommunications Standards Institute whose goal is to define standards in the broad area of telecommunications systems 6 Radio Frequency Identification Fundamentals and Applications, Bringing Research to Practice Class Device description Inductive loop coil transmitter Inductive loop coil transmitter Customized large size loop antennas only E-field transmitter Antenna area S < 30 m2 < 30 m2 Length of antenna < λ/4 or < 75 m / f where: λ – wavelength f – frequency in MHz < λ/4 or < 75 m / f Description Integrated antenna with a transmitter or directly connected with it Designed antenna with attached instructions > 30 m2 - - - - - Table Description of classes of transmitting device in accordance to ETSI EN 300 330 In the Part 1: Technical characteristics and test methods of the ETSI EN 300 330: Electromagnetic compatibility and Radio spectrum Matters (ERM); Short Range Devices (SRD); Radio equipment in the frequency range kHz to 25 MHz and inductive loop systems in the frequency range kHz to 30 MHz, are defined four classes of transmitting devices, which are summarized in Table Due to the fact that all of RFID systems with inductive coupling operating in the frequency range kHz to 30 MHz belong to Class and 2, the restrictions of the magnetic field strength are compared in Table only for those classes of transmitting devices Nr Frequency f, MHz Magnetic field strength limits at 10 m H10max, dBμA/m 0.009 ≤ f < 0.315 30 0.009 ≤ f < 0.03 72 0.03 ≤ f < 0.05975 0.06025 ≤ f < 0.07 0.119 ≤ f < 0.135 72 at 0,03 MHz descending dB/oct 0.05975 ≤ f < 0.06025 0.07 ≤ f < 0.119 0.135 ≤ f < 0.140 42 0.140 ≤ f < 0.1485 37.7 0.1485 ≤ f < 30 -5 0.315 ≤ f < 0.600 -5 3.155 ≤ f < 3.400 13,5 7.400 ≤ f < 8.800 9 10.20 ≤ f < 11.00 10 6.765 ≤ f < 6.795 13.553 ≤ f < 13.567 26.957 ≤ f < 27.283 42 11 13.553 ≤ f < 13.567 60 Table Magnetic field strength limits at 10 m from radiation source Field Conditions of Interrogation Zone in Anticollision Radio Frequency Identification Systems with Inductive Coupling The restrictions listed in items and of Table for the frequency bands 9-10 kHz and 119-135 kHz are valid for loop antennas with an area of S ≥ 0.16 m2 If the antenna surface of the transmitting devices is in the range from 0.05 m2 to 0.16 m2, the limit value of H10max has to be corrected according to the following relationships: ⎛ S H 10max,cor = H 10max + 10 log ⎜ ⎜ 0,16 m2 ⎝ ⎞ ⎟ ⎟ ⎠ (4) It is necessary to reduce the limit values given in Table by 10 dB for loop antennas with an area of S