Effects of Reader-to-Reader Interference on the UHF RFID Interrogation Range

In this paper, the effects of ultrahigh-frequency band passive radio-frequency identification (RFID) reader-to-reader interference are investigated in terms of the interrogation range. A reader-to-reader interference model based on interference statistics is proposed, and the nominal interrogation range of a desired reader is derived by this model. In order to evaluate the RFID reader-to-reader interference quantitatively, the interrogation-range-reduction ratio (IRRR) is also defined. For a simple case with only one interfering reader, the analytic and experimental results are in good agreement. Reader–reader distance achieving 0% IRRR, indicating no interference between the readers, is 1200 m for the multiple-reader environment. Additionally, IRRR values are calculated in various environments according to the North American and Korean regulations. The maximum number of allowable interfering readers is then calculated by the proposed interference model and a target IRRR.      

Array‐based reader anti‐collision scheme for highly efficient RFID network applications

Radio frequency identification (RFID) is a technology for identifying objects by radio signal. The reader collision problem is caused by the interrogation zones overlap of multiple readers, and leading to incorrect and unreliable data. This study proposes an array‐based reader anti‐collision scheme (ARCS) for solving the reader‐to‐tag interference problem. This mechanism uses array and grouping techniques to schedule the active readers to reduce the read cycle (RC) time. The ‘RC’ and ‘collision ratio (CR)’ measures serve as performance indexes in the proposed scheme. From ‘RC’ comparison, the ARCS mechanism has the maximum improvement of 55 per cent as compared with the existing mechanisms. Furthermore, take ‘CR’ index, ARCS has the maximum improvement of 42 per cent as compared to the others. Copyright © 2008 John Wiley & Sons, Ltd.     

An Efficient Reader Anticollision Algorithm in Dense RFID Networks With Mobile RFID Readers

In parallel with the proliferation of radio-frequency identification (RFID) systems, many RFID readers have been increasingly employed. In such an environment, collision among readers becomes a serious problem. Existing anticollision algorithms, depending on the information of neighboring readers, may require constant effort in order to grasp such information. Although it may be given by a server or a coordinator, they may not be suitable in dense and dynamic RFID networks with mobile readers. In this paper, we propose an efficient reader anticollision algorithm using a polling server in dense and dynamic RFID networks with mobile readers. Owing to the assistance of the server, the readers can rapidly decide whether they can work or not without interfering neighbors and can be easily synchronized. Our proposed algorithm is simple and makes readers aware of neighbors to minimize reader collisions. Performance evaluation shows how many readers can operate in a network and indicates that our proposed algorithm is more efficient than distributed color selection, colorwave, and hierarchical Q-learning algorithm, particularly in dense and mobile environments.      

Network Information Security Data Protection Based on Data Encryption Technology

Today Radio Frequency Identification systems (RFID) are one of the most usable automated wireless identification technologies in the internet of things. Identification systems can exchange data remotely by communicating between a tag and a reader with sending radio waves. The main challenge of identification systems with radiofrequency in a dense RFID network is the collision, which occurs when readers are located in each other's interference range and start reading tags simultaneously. With these collisions happening, readers cannot read all the tags around them in the efficient time durations. In this research, using a distributed method and the channel listening technique, readers select a time interval to take the control channel by the Geometric Probability Distribution Function. Also, by measuring the signal strength from neighboring readers and sharing tag information, there will be an increase in the throughput of identification systems through radio waves while avoiding all kinds of collisions in the control channel. Extensive results show that the proposed method has better throughput and has less average waiting time.

     

Reliable ALE middleware for RFID network applications

Radio frequency identification (RFID) technology adopts the air interface to deliver the information required for object identification. The RFID system is convenient to manage and operate, and is widely encouraged by the large‐scale chain industry. Additionally, electronic product code (EPC) network technology allows immediate, automatic identification and sharing of information on items in the supply chain. This work proposes an RFID service middleware with a highly reliable and efficient application‐level event (ALE)‐based prototype mechanism according to EPCglobal. A Student Muster Roll (SMR) application test bed is implemented in the proposed ALE‐based scheme. The SMR system can be employed to manage the absentee records of students in a class, and can manage and control several operation multi‐reader devices simultaneously. The proposed scheme can filter attendance accurately, eliminating the possibility of reduplication in student records. Performance evaluation results indicate that the proposed novel scheme is much more efficient and reliable than a naive ALE scheme. Copyright © 2008 John Wiley & Sons, Ltd.     

A practical quadratic residues based scheme for authentication and privacy in mobile RFID systems

In this paper we propose a novel approach to authentication and privacy in mobile RFID systems based on quadratic residues and in conformance to EPC Class-1 Gen-2 specifications. Recently, Chen et al. (2008) [10] and Yeh et al. (2011) [11] have both proposed authentication schemes for RFID systems based on quadratic residues. However, these schemes are not suitable for implementation on low-cost passive RFID tags as they require the implementation of hash functions on the tags. Consequently, both of these current methods do not conform to the EPC Class-1 Gen-2 standard for passive RFID tags which from a security perspective requires tags to only implement cyclic redundancy checks (CRC) and pseudo-random number generators (PRNG) leaving about 2.5k–5k gates available for any other security operations. Further, due to secure channel assumptions both schemes are not suited for mobile/wireless reader applications. We present the collaborative authentication scheme suitable for mobile/wireless reader RFID systems where the security of the server–reader channel cannot be guaranteed. Our schemes achieves authentication of the tag, reader and back-end server in the RFID system and protects the privacy of the communication without the need for tags to implement expensive hash functions. Our scheme is the first quadratic residues based scheme to achieve compliance to EPC Class-1 Gen-2 specifications. Through detailed security analysis we show that the collaborative authentication scheme achieves the required security properties of tag anonymity, reader anonymity, reader privacy, tag untraceability and forward secrecy. In addition, it is resistant to replay, impersonation and desynchronisation attacks. We also show through strand space analysis that the proposed approach achieves the required properties of agreement, originality and secrecy between the tag and the server.     

RFID-based localization with Non-Blocking tag scanning

The simple and cheap passive RFID tag systems have recently been used for efficient localization of indoor mobile robots, where each RFID tag stores its own absolute position and the mobile robot carrying an RFID reader scans the RFID tags to localize itself. The available localization schemes using passive RFID systems do not consider the scanning delay which may cause location estimation error, especially when the robot moves at a high speed. In this paper, a new Non-Blocking scanning (reading) scheme is proposed to avoid collisions so that the scanning delay, and consequently the localization error, can be reduced. This scheme avoids collisions among tag replies by assigning tag IDs based on the FCA coloring scheme. Theoretical and simulation studies indicate that the new Non-Blocking scheme combined with the new tag arrangement pattern can achieve a good RFID localization performance in terms of both estimation error and scanning delay with reduction of tag/reader required complexities.     

一种具有阅读器匿名功能的射频识别认证协议

在射频识别(RFID)的应用中,安全问题特别是用户隐私问题正日益凸显。因此,(用户)标签信息的隐私保护的需求越来越迫切。在RFID系统中,标签的隐私保护不仅是对外部攻击者,也应该包括阅读器。而现有许多文献提出的认证协议的安全仅针对外部攻击者,甚至在外部攻击者的不同攻击方法下也并不能完全保证安全。该文提出两个标签对阅读器匿名的认证协议:列表式RFID认证协议和密钥更新式RFID认证协议。这两个协议保证了阅读器对标签认证时,标签的信息不仅对外部攻击者是安全的而且对阅读器也保持匿名和不可追踪。相较于Armknecht等人提出的对阅读器匿名和不可追踪的认证协议,该文所提的协议不再需要增加第三方帮助来完成认证。并且密钥更新式RFID匿名认证协议还保证了撤销后的标签对阅读器也是匿名性和不可追踪的。     

基于LTE-A的大规模物流系统中射频识别标签处理算法的研究(英文)

The Long Term Evolution Advanced (LTE-A) and Internet of Things (IoT) are two of the most popular topics that receive vast attentions in the filed of information technologies. Radio Frequency Identification (RFID) greatly pushes IoT forward to practical utilization. In RFID system, one of the key issues is the collision among tags when reader tries to identify several of them simultaneously. In this paper, the authors proposed a RFID tag management scheme for cargo identification and tracking based on the L...     

RFID系统中面向服务的动态资源配置优化机制

针对物联网中RFID(radio frequency identification)系统的tag和reader的速率不匹配及其资源受限问题,从理论上对tag和reader之间的协作通信上下文进行分析,提出一种面向服务的RFID系统资源配置优化机制,该机制利用tag与reader的组件QoS(quality of service)信息建立闭环控制框架,使用3种控制策略根据其资源状态和类型调节QoS参数。通过实验对机制进行了性能分析和验证,结果表明,该优化机制有效地提高RFID系统的吞吐量,高效地使用系统资源,减少了能量消耗和reader-to-reader干扰。     

Efficient RFID Authentication Using Elliptic Curve Cryptography for the Internet of Things

The Internet of Things (IoT) is an expansion of Internet-based sensing, processing and networking. As a key technique of the IoT, the Radio Frequency Identification (RFID) had a prosperous development in the past decade. Security schemes were also proposed to ensure secure RFID authentication. This paper analyzes security weaknesses found in previous schemes and proposes a new RFID authentication scheme using Elliptic Curve Cryptography (ECC). Security analysis results show that the proposed scheme can meet security requirements of RFID authentication while requiring no extra cost in terms of performance.     

D2D communications with subchannel reusing for throughput‐guaranteed relay selection in LTE

Using full‐duplex relaying in device‐to‐device (D2D) communication, spectrum efficiency can be further improved as compared with traditional half‐duplex relaying. Due to the increasing demands for more system capacities and higher data rate, a throughput‐guaranteed and power‐aware relay selection mechanism is essential so that services can be successfully accomplished within tolerable power consumption. It is also imperative to prevent cellular users from interfering and preserve resources for more users at the same time. In current paper, we proposed an efficient relay selection scheme with subchannel reusing. Using the nonconflict group discovery algorithm, firstly, we divided D2D pairs into different groups based on the neighbor lists of all the devices. The D2D pairs in the same group were considered nonconflictive. By building a matrix that represents the power consumption of D2D transmission peers through relays, we proposed a group‐oriented relay selection scheme based on the Hungarian method allowing subchannel reuse over relay‐assisted D2D networks. Applying this mechanism, different D2D pairs are able to transmit messages at the same subchannel, whenever they are in the same group. Better throughput and spectrum usage than currently available relay selection schemes without subchannel reusing can be obtained. Particularly, more D2D pairs in high dense networks can be accommodated, and spectrum resources can be better preserved. The simulation results showed that our proposed mechanism can improve the total throughput by up to 35% as compared with an existing relay selection scheme without subchannel reusing, called as PRS‐D2D, when most D2D pairs are in a few groups.     

Low Access Delay Anti-Collision Algorithm for Readers in Passive RFID Systems

Even though radio frequency identification (RFID) systems are spreading more and more as a medium for identification, location and tracking purposes, some reliability issues of these systems still need to be solved. In fact, RFID readers and tags experience collisions when sharing the wireless transmission channel over the same area. In this work, we propose a centralized scheduling-based algorithm as possible candidate solution for the reader collision problem in passive RFID systems. This algorithm has been designed taking into account the circuitry limitations of the tags, which do not allow the usage of frequency or code division multiple access schemes in passive RFID systems. The solution herewith proposed, which is suitable for those scenarios involving static or low mobility readers, aims at preventing reader collisions and provides at the same time low channel access delay to the readers. The performance of this algorithm has been tested via computer simulations. The results show that the proposed solution strongly reduces collision occurrences and, especially in static scenarios, provides low access delay to the readers during the channel contention phase.     

Channel and Time Slot Allocation for Dense RFID Networks

This paper presents a constraint satisfaction approach to the reader collision problem in dense mode environments for static RFID networks. Our method assigns available channels and time slots to the RFID readers to increase the read rate while satisfying all the interference constraints. We model the problem with a hybrid frequency and time division multiplexing constraint satisfaction for reader anti-collision and assign workable channels and time slots to each reader using backtracking search algorithms. A depth-first-search based on backtracking was performed to find solutions to constraint satisfaction problems. Instead of performing an exhaustive search for the optimal result, we adopted good variable ordering heuristics as branching strategies where the search can be completed quickly. Thus, the search space is greatly reduced, and approximate solutions are found instantly. To find appropriate heuristics, we applied a problem classifying rule to determine the quality of the variable ordering heuristics. Computer simulations of the comparable performance of some variable ordering algorithms in the channel and time slot allocation for dense RFID networks are presented.     

RFID reader collision problem: performance analysis and medium access

The RFID reader collision problem, in which an RFID reader's interrogation is interfered by other concurrent readers' transmission, is considered an important issue to reliable operation and thus to the wide‐spread deployment of RFID networks. In this paper, we present modeling and analysis of the RFID reader collision problem. We observe asymmetry between an RFID reader's and a tag's communication capabilities and develop an RFID radio model based on the asymmetry. By the model, we characterize the spatial reuse of RFID reader networks, and derive concurrent interrogation distance beyond which readers can transmit simultaneously without causing collision and the carrier sense threshold corresponding to the distance. We also examine the dual‐channel mode where available bandwidth is divided into two channels by which reader‐to‐tag communication and tag‐to‐reader communication are separated. We analyze and evaluate the performance of the dual‐channel mode in terms of spatial reuse and interrogation completion time. Copyright © 2010 John Wiley & Sons, Ltd.     

基于RFID技术的身份识别系统设计与实现

RFID射频识别是一种非接触式的自动识别技术,它通过射频信号自动识别目标对象并获取相关数据,识别工作无须人工干预,可工作于各种恶劣环境。RFID技术可识别高速运动物体并可同时识别多个标签,操作快捷方便。首先简要介绍了RFID技术的概念、优势以及RFID系统的组成和工作原理。并提出了一种基于RFID技术的身份识别系统,并提出标签的存储防静态分析和存储数据的访问控制;以及读卡器和标签之间的认证和密钥协商协议的方案,以满足身份识别的要求。     

基于口令认证的RFID系统安全协议及其BAN逻辑分析

本文提出一种新的基于口令认证的RFID系统安全协议.该方法充分利用RFID低等级标签提供的有限资源:访问口令(PW)、标签的标识码(ID)和伪随机函数等建立RFID系统读写器和标签双向认证的安全协议,对该协议抵抗各种攻击的安全性进行理论分析并对该协议的认证功能进行BAN逻辑的形式化分析.结果表明该协议能够有效抵御在线和离线字典攻击、伪装攻击、重放攻击以及流量分析和跟踪攻击,因而解决了RFID系统的安全问题.     

HF RFID Reader Antenna with Loop Switch for Avoiding Magnetic Coupling

This paper studies the magnetic coupling between two adjacent loop antennas that are parallel to each other in a plane and presents a new practical method to avoid the resulting magnetic coupling interference. The study focuses on the high frequency radio‐frequency identification (RFID) system for casino applications, where several loop antennas are closely built into a game table to monitor gaming chips. In this case, neighboring loop antennas may severely interfere with each other by magnetic coupling, which leads to the malfunction of the RFID system. In this paper, we present a practical loop antenna with a new loop switch circuit for avoiding magnetic coupling. The loop switch circuit is integrated with a matching circuit and automatically operated by using an interrogating signal from a reader. We verified the validity of the proposed design by showing that an RFID reader with the proposed antenna can exactly and separately read the gaming chips placed on the different betting zones of a game table.     

一种最大化系统用户速率下限的MIMO-MAC有限反馈干扰对齐算法

针对2小区MIMO-MAC中传统有限反馈干扰对齐码字选择方案的不足,本文提出了一种最大化用户速率下界的直接码字选择方案,并结合比特分配算法来减少和速率的损失,同时采用最大信干扰算法译码.不同于传统的基于最小弦距离或对齐度准则来选择码字,本文从最大化用户速率下界的角度来选择的码字;进一步地,在格拉斯曼空间中生成与期望预编码接近的码字集合,在该集合中只需简单的搜索便可找到优化的码字组合,同时实现了低复杂度和次优的全局搜索.仿真实验表明,相对于现有的典型算法,本文算法在提升系统和速率的同时,也提高了系统用户速率的下界.     

Interference management with adaptive fractional frequency reuse for LTE-A femtocells networks

This paper presents a novel interference management strategy, to adaptively choose the best fractional frequency reuse (FFR) scheme for macro and femto networks. The strategy aims to maximize the system throughput taking into account a number of system constraints. Here, the system constrains consist of the outage constraints of two-tier users and macrocell spectral efficiency requirement. The detailed procedures of our proposed strategy are: 1) A reference signal received power (RSRP) based selection algorithm is presented to adaptively select the optional FFR schemes satisfying the outage constraints. 2) Considering the macrocell spectral efficiency, the optimal FFR scheme is selected from the optional FFR schemes at MeNB side, to achieve the maximum system throughput in two-tier femtocell networks. We study the efficacy of the proposed strategy using an long term evolution advanced (LTE-A) system level simulator. Simulation results show that our proposed interference management strategy can select the best FFR scheme to maximize the system throughput, and the FFR schemes derived by using RSRP-based selection algorithm can be the effective solutions to deploy femtocells in macrocells.