一种无源射频识别编解码电路的设计与验证

提出了一种基于ISO/IEC 14443协议的高频13.56 MHz RFID芯片的数字编解码电路结构,采用Altera FPGA搭建验证系统,进行了系统设计的仿真与验证。该电路实现了RFID标签芯片通信时所需要的副载波调制后曼彻斯特编码和修正密勒码的解码,并为后端的协议栈电路设计了SPI从机通信接口。     

基于ISO18000-6C协议标准的RFID阅读器设计

为了满足市场需求,提高阅读器读写效率,提出一种基于IS018000-6C协议标准的RFID阅读器设计方案.该阅读器基带处理部分采用ARM+ FPGA组合实现,利用FPGA编解码速度快的特点并结合ARM的控制优势,使得该阅读器具有识别速度快、识别率高的特点;阅读器的射频发射电路采用两级功率放大,具备能很好地抑制噪声、保持很好的线性度、辐射功率满足要求、识别距离远的特点;阅读器的接收回路采用四路解调,可以很好地解决接收“模糊点”.     

Lightweight mutual authentication RFID protocol for secure multi-tag simultaneous authentication in ubiquitous environments

The Journal of Supercomputing - RFID is a core technology enabling a ubiquitous environment. Its various applications have shown great progress in our daily life in fields such as distribution...     

一种轻量级RFID安全协议

在分析了几种现有的典型RFID安全协议的特点和缺陷的基础上,提出了一种轻量级的RFID安全协议,该协议将一次性密码本与询问一应答机制相结合,实现了安全高效的读取访问控制,最后建立该协议的理想化模型,利用BAN逻辑对该协议进行了形式化分析,在理论上证明其安全性.     

A novel-Q DFSA algorithm for passive RFID system

The tag detection ability of Passive Radio Frequency Identification (RFID) systems are critically challenged by the collision occurrence due to simultaneous responding tags during the identification process. The dynamic scheduling of the frame size governed by Dynamic Frame Size ALOHA(DFSA) process, by adjusting the frame lengths according to the size of tag population can avoid the collisions during the identification. However, the performance of DFSA majorly depends on the frame size selection policy which in previous studies was adopted to achieve the target of throughput maximization during a frame. This condition is obtained at the cost of equating the frame size up to the number of estimated tags responding during the time frame. This approximation enhances the throughput value but contributes to massive energy wastages as the frame lengths approach to a very large value in large tag population size. Therefore, it is essential to develop the new frame size estimation policy for DFSA achieving the aim of optimization between throughput and energy for improved time and energy performance. In this paper, we have proposed an EPC C1G2 standards based Novel-Q DFSA algorithm which optimizes the frame size accounting both the energy and the throughput. The combined throughput and energy trade-offs are measured through Energy–Time-Delay (ET) cost which is minimum for our proposed algorithm compared to the existing solutions. Furthermore, the Throughput-Time Delay product approves the stability in large population size making it suitable for numerous identification applications.     

A novel low-noise high-linearity CMOS transmitter for mobile UHF RFID reader

A novel CMOS transmitter with low TX noise and high linearity is implemented in a 0.18μm 1P6M standard CMOS process for Mobile UHF RFID reader.Adopting double-sideband amplitude-shift-keying(DSBASK)as the only modulation is supported,this transmitter has very low power consumption.A novel analog baseband circuit is proposed to reduce the transmitter noise.With a G′′m–cancellation technology,a highly linear up-conversion active mixer and a power amplifier driver are designed.The transmitter has a measured output1 dB compression point of 13.4 dBm.Occupying a silicon area of about 1 mm2and consuming 144 mW from a1.8 V voltage supply,the transmitter makes the Mobile UHF RFID reader communicate with a transponder in a distance of 1 m conveniently.     

A framework for multiuser distributed virtual environments

A framework for multi-user distributed virtual environments (DVEs) has been proposed. The proposed framework, incorporating two models (the functional model and the interconnection model), attempts to represent the common functionality, communication issues and requirements found in multi-user DVEs. The functional model concentrates on the DVE's functionality, while the interconnection model concentrates on how the components are interconnected to realize the required functionality. The models have been specified using the Unified Modeling Language (UML). An experimental case study demonstrates the applicability and generality of the proposed approach.     

A synchronization algorithm for distributed multimedia environments

Network synchronization plays a significant role in transmitting multimedia objects over computer networks. Even packets from a single channel must be synchronized due to the problems in a packet switching environment, such as network jitter, frequency, and time offsets. We present an algorithm that determines the set of packets generated periodically by various participants arriving at a node. The basic advantage of the proposed algorithm is that the receiver estimates the reference times (expected arrival times of the packets) and achieves synchronization, without knowledge of the packet delays. The accuracy is improved and the complexity is reduced by predicting the time/frequency offsets between the clocks at the source and the mixer. The error is calculated by the Chernoff bound, demonstrated by simulation, and shown to be acceptable in practical applications.     

生产线嵌入式RFID终端读写器设计

RFID技术由于其可靠性高、适应环境广、总体成本低已经在制造业信息化和物流领域发挥了巨大作用,如何更有效,精确的读取RFID信息成为影响RFID在工业生产线上大量应用的关键,本文论述了借助于ARM体系平台和Linux操作系统,在硬件和软件上实现生产线RFID终端读写器的设计方案,样机已经在冰箱生产线上进行了实验,并取得较好的效果。     

A novel compact low-power direct conversion receiver for mobile UHF RFID reader

A novel direct conversion receiver with low cost and low power is implemented in a 0.18 μm 1P6M standard CMOS process for a Mobile UHF RFID reader.A highly linear active mixer with low flicker noise and low noise active load is proposed.An efficient and low cost on-chip DC offset voltage canceling scheme is adopted with a high-input-impedance four-input OPAMP to buffer the output of the DC offset canceller(DCOC) block.The receiver has a measured input 1 dB compression point of 2 dBm and a sensitivity of 72 dBm in the presence of the large leakage signal from the transmitter.Only occupying a silicon area of 2.5 mm 2 and consuming 21 mA from a 1.8 V supply,the receiver makes the mobile UHF RFID reader to communicate with a transponder in a distance of 1 m conveniently.     

A lightweight anti-desynchronization RFID authentication protocol

Radio frequency identification (RFID) technology has been widely used in ubiquitous infrastructures. However, resource constraint in the low-cost RFID systems has posed potential risks such as privacy and security problems, becoming adoption barrier for RFID-based applications. In this paper, current security issues in RFID are introduced firstly. Then, we propose a lightweight Anti-desynchronization privacy preserving RFID authentication protocol. It is particularly suitable for the low-cost RFID environment for only the capacity of one-way hash function and XOR operation is needed. In this lightweight Anti-desynchronization RFID authentication protocol, the back-end server keeps the history of the random key update to prevent the active attackers from de-synchronizing the shared secret between the tag and the back-end server. The security and the performance of the proposed protocol are analyzed as well.     

A distributed architecture for scalable private RFID tag identification

The fast growth of Radio Frequency IDentification (RFID) implies a deployment challenge, namely how to keep this technology scalable without renouncing security and privacy features. This paper focuses on combining tag privacy and scalability using the hash locks mechanism. Our contribution is twofold: (i) a cell-based architecture is proposed in which the readers co-operate in order to conduct tag identification in a private and scalable way; (ii) a communication protocol for the proposed architecture is defined and assessed. The proposed architecture and protocol solve the scalability shortcomings of private RFID identification pointed out by Juels and Weis.     

RFID读写器验证算法的研究与设计

分析了当前的防伪技术,着重研究防伪机制和加密算法,结合信息安全与RFID技术理论的防伪技术以及RFID的国际标准提出基于SHA-1算法的RFID读写器数字签名验证算法。同时,提出一种基于DSP的防伪读写器样机系统设计。     

A directional data dissemination protocol for vehicular environments

This paper presents a simple and robust dissemination protocol that efficiently deals with data dissemination in both dense and sparse vehicular networks. Our goal is to address highway scenarios where vehicles equipped with sensors detect an event, e.g., a hazard and broadcast an event message to a specific direction of interest. In order to deal with broadcast communication under diverse network densities, we design a dissemination protocol in such a way that: (i) it prevents the so-called broadcast storm problem in dense networks by employing an optimized broadcast suppression technique; and (ii) it efficiently deals with disconnected networks by relying on the store-carry-forward communication model. The novelty of the protocol lies in its simplicity and robustness. Simplicity is achieved by only considering two states (i.e., cluster tail and non-tail) for vehicles. Furthermore, vehicles in both directions help disseminating messages in a seamlessly manner, without resorting to different operation modes for each direction. Robustness is achieved by assigning message delivery responsibility to multiple vehicles in sparse networks. Our simulation results show that our protocol achieves higher delivery ratio and higher robustness when compared with DV-CAST under diverse road scenarios.     

一种基于超高频RFID的无线无源压力传感器

电力设备在长期运行中,受环境影响,可能会发生失压、形变现象。针对这种现象,设计了一种基于UHF RFID的无线无源压力传感器,能够在不接触电力设备的情况下获得设备的表面压力信息。基于UHF RFID的压力传感器标签主要由阻抗自适应RFID芯片、UHF频段RFID偶极子天线、金属极板和支撑弹簧构成。电力设备的形变会导致安装在设备上的金属极板与偶极子天线的相对位置变化,导致RFID天线的阻抗变化,RFID芯片内部会通过自动调节输入阻抗电容以匹配RFID天线阻抗的变换。通过检测RFID芯片内部匹配阻抗的电容值,可以推出电力设备的形变情况,形成一一对应的关系,从而实现无线无源压力传感功能。     

一种无后端数据库的RFID安全认证协议

针对使用后端数据库模式的无线射频识别(RFID)安全协议的弊端,基于已有的无后端数据库安全协议,提出了一个改进的无后端数据库的RFID安全认证协议.通过安全性分析和效率比较,证明该协议不仅实现了真正的双向认证和标签匿名,而且使标签端只需进行一次哈希运算,大大提高了系统的效率和可行性.因此该协议与已有的无后端数据库安全协议相比,更安全、更高效.     

A secure file sharing service for distributed computing environments

Distributed cryptographic file systems enable file sharing among their users and need the adoption of a key management scheme for the distribution of the cryptographic keys to authorized users according to their specific degree of trust. In this paper we describe the architecture of a basic secure file sharing facility relying on a multi-party threshold-based key-sharing scheme that can be overlaid on top of the existing stackable networked file systems, and discuss its application to the implementation of distributed cryptographic file systems. It provides flexible access control policies supporting multiple combination of roles and trust profiles. A proof of concept prototype implementation within the Linux operating system framework demonstrated its effectiveness in terms of performance and security robustness.     

A distributed QoS-Aware multicast routing protocol

This paper discusses the multicast routing problem with QoS constraints, and describes a network model that is suitable to research such routing problem. The paper mainly presents a distributed QoS-aware multicast routing protocol (QMRP). The QMRP can operate on top of the unicast routing protocol. It only requires the local state information of the link (or the node), but does not require any global network state to be maintained. The QMRP can significantly reduce the overhead for constructing a multicast tree with QoS constraints. In QMRP, a multicast group member can join or leave the multicast session dynamically, which can support dynamic membership. The protocol can search multiple feasible tree branches, and select the optimal or near-optimal branch for connecting the new receiver to the multicast tree if it exists. In this paper, the proof of correctness and complexity analysis of the QMRP are given, and the performance measures of the protocol are evaluated using simulation. The study shows that QMRP provides an available approach to multicast routing with QoS constraints and dynamic membership support.Received: 3 April 2003, Published online: 2 September 2003     

A compensation-based approach for view maintenance in distributed environments

Data integration over multiple heterogeneous data sources has become increasingly important for modern applications. The integrated data is usually stored as materialized views to allow better access, performance, and high availability. In loosely coupled environments, such as the data grid, the data sources are autonomous. Hence, tie source updates can be concurrent and cause erroneous results during view maintenance. State-of-the-art maintenance strategies apply compensating queries to correct such errors, making the restricting assumption that all source schemata remain static over time. However, in such dynamic environments, the data sources may change not only their data but also their schema. Consequently, either the maintenance queres or the compensating queries may fail. In this paper, we propose a novel framework called DyDa that overcomes these limitations and handles both source data updates and schema changes. We identify three types of maintenance anomalies, caused by either source data updates, data-preserving schema changes, or non-data-preserving schema changes. We propose a compensation algorithm to solve the first two types of anomalies. We show that the third type of anomaly is caused by the violation of dependencies between maintenance processes. Then, we propose dependency detection and correction algorithms to identify and resolve the violations. Put together, DyDa extends prior maintenance solutions to solve all types of view maintenance anomalies. The experimental results show that DyDa imposes a minimal overhead on data update processing while allowing for the extended functionality to handle concurrent schema changes.