Research of Improved ALOHA Anti-collision Algorithm in RFID System

Private companies and government have decided to provide Radio Frequency Identification (RFID) systems in places of free access to the population. However, as a result of such exposition, these systems become vulnerable to Denial of Service (DoS) attacks that can cause unavailability in the services. Furthermore, another complicating factor in that context regards the equipment or devices used on RFID systems, since they operate in frequency bands reserved for secondary communication systems, and consequently they have too few computational resources to deal with malicious electromagnetic interferences. Therefore, in this paper an Intrusion Detection System (IDS) is proposed to identify the occurrence of the malicious behavior and to notify the system operator about one specific type of electromagnetic interference in RFID systems - the Jamming attack. The obtained results of the system show the jamming attacks are detected prior of having a significant impact on the communication between the RFID reader and the tag - i.e., the jamming attack was detected even with insufficient power to impact on communication.

Radio Frequency IDentification (RFID) systems have rich applications in daily life. A crucial problem in RFID systems is to estimate the cardinality of RFID tags. Most exiting probabilistic RFID cardinality estimation algorithms utilize a certain pattern hidden in the response vector formed by the tag responses to make estimators. In this paper, we argue that finding the patterns is actually not necessary! In this paper, we present a novel approach to RFID cardinality estimation by making the full use of the whole response vector. We characterize the critical relationship between the number of RFID tags and the specific distribution of the bits in the response vector. In this paper, we consider two kinds of responses, i.e., empty / non-empty responses and empty / singleton / collision responses. To cater for RFID systems with a very large number of tags, we also generalize our estimation approach to handle geometrically distributed response vectors. Both rigid theoretical analysis and extensive simulations have been conducted and the conclusive results demonstrate that our approach is more accurate than existing state-of-the-art RFID estimation approaches.

Remote technologies are changing our way of life. The radio frequency identification (RFID) system is a new technology which uses the open air to transmit information. This information transmission needs to be protected to provide user safety and privacy. Business will look for a system that has fraud resilience to prevent the misuse of information to take dishonest advantage. The business and the user need to be assured that the transmitted information has no content which is capable of undertaking malicious activities. Public awareness of RFID security will help users and organizations to understand the need for security protection. Publishing a security guideline from the regulating body and monitoring implementation of that guideline in RFID systems will ensure that businesses and users are protected. This chapter explains the importance of security in a RFID system and will outline the protective measures. It also points out the research direction of RFID systems.

In recent years, numerous authentication protocols for radio frequency identification (RFID) systems have been proposed to protect privacy. Due to the hardware resource limitation on RFID tags, the majority of these protocols are based on symmetric-key ciphers. However, most of them lack scalability at the reader side as they require a linear or logarithmic search proportional to the number of tags in the system in order to authenticate a tag. Recently proposed scalable protocols require a constant-time search and utilize hash look-up tables. However, the storage requirement of the hash-table in these protocols is very large, therefore not practical. Moreover, previous proposals do not support dynamic resizing where the number of tags changes during the life time of the RFID system. In this paper, a new Re-Hash technique is presented to reduce the hash-table storage in constant-time authentication protocols. To the best of our knowledge, it offers the smallest storage cost in comparison to previous proposals. The Re-Hash technique is also further adapted to support the dynamic scalability for RFID systems.

Every year researchers and engineers are finding new and useful applications for Radio Frequency Identification (RFID) systems (Finkenzeller, 2003). Because of the growing use of RFID systems, many different areas of research have also been developed to improve the performance of such systems. A few of these areas of research include novel antenna designs (Rao et at., 2005; Calabrese & Marrocco, 2008; Amin et al. 2009), analysis on the backscatter properties of RFID tags (Yen et al., 2007; Feng et al., 2006), mutual coupling between RFID tags (Li et al., 2008; Owen et al., 2009) and the deployment of RFID systems to complex and extreme environments (Qing & Chen, 2007; Sanford, 2008). There are many aspects to each area of research in RFID. A major topic in many of these areas involves research on the antenna design for RFID tags. This chapter will focus on the design of efficient space-filling antennas for passive UHF RFID tags. First, an introduction to RFID systems is presented. This is done by describing the major components in a RFID system and how they communicate. Then, the particular backscattering properties of a passive tag are described from a unique electric field integral equation standpoint and from an overall systems perspective (i.e., using the Friis transmission equation). This discussion will then be followed by a section describing a practical design process of various space-filling antennas for passive tags. Finally, a summary of future work and a conclusion about the chapter is presented.

This paper discusses the separation of signals in multiple-tag radio frequency identification (RFID) systems. First, a model for the RFID system in both single and multiple tag environments is presented. Then, an analytical constant modulus algorithm (ACMA) for the blind source separation problem is reviewed. An alternative approach to the traditional ACMA using joint diagonalization is considered. Finally, both the ACMAs are applied to the multiple-tag RFID environment and performance of the system is studied. Simulations are carried out for 4-QAM and 16-QAM modulations at tag and analyses of the simulation results reveal that the ACMA with joint diagonalization takes lesser CPU time to execute compared to the traditional ACMA, but with higher average modulus error (AME). The variation of system performance with the number of measurements, SNR (signal to noise ratio), number of tags and number of antennas at the reader is also studied. Based on these, some design guidelines are presented. Interestingly both the ACMA algorithms work for the 16-QAM case and yield trends similar to those of 8-PSK and 4-QAM.

In radio frequency identification (RFID) system, the reader-to-reader interference leads to reader collision that disturbs readers in tag recognition. The existing reader anti-collision techniques based on TDM or FDM are inefficient solutions to the reader collision problem since they do not consider jointly the distance between the interfering readers and the frequencies, and time slots that readers use. In this paper, we formulate a TDM/FDM-based reader-to-reader interference model to analyze the effects of the above factors and an optimization problem to maximize the RFID system performance. We then propose a novel resource allocation technique based on genetic algorithm (RA-GA) to solve the optimization problem. The RA-GA includes a unique encoding scheme and fitness function to obtain an optimal resource allocation for the RFID system effectively. Simulation results show that the RA-GA is superior to the resource allocation based on random method.

In recent years, the research on Radio Frequency Identification (RFID) system has presented certain solutions that can meet the corresponding security requirements to some extents. However, the issues with multiple databases in RFID system, which are common in the real world, have gained little attention in the existing schemes. Although ONS (Object Name Service) solution is aimed at supporting multi-database in RFID system, it still has great security risk because of the lack of protection of the tag ID. In this paper, a new solution is presented which can provide sound protection of the tag ID and is adaptable to multiple databases, which can meet the security requirements of RFID system.

Radio Frequency IDentification (RFID) technology successfully integrates radio transmitter and receiver, small size memory space and control circuitry to remotely store and retrieve data via wireless RF transceiver. As low-cost RFID tag can be massively manufactured by semiconductor industry, new applications associated with RFID technology have emerged rapidly such as inventory tracking, book storage and management, and airport baggage handling. Generally an RFID system is composed of many RFID tags (or tagged objects), at least one RFID reader, and one backend application system with database. An RFID tag gains its operation energy from query signals that are radio waves transmitted by RFID reader. Once a tag responds the query with its stored information to RFID reader, usually a unique identity number or string, the RFID system can recognize the tag carrier and perform required business logic operation. As RFID technique is widely used in supply chain management, the corresponding RFID application systems are expected to process and manage large amount of tagged objects at a predefined period of time regularly. Therefore, for large-scaled RFID applications, tag reading throughput is very critical since it will affect the total data processing time. To measure tag reading throughput of a RFID system, two performance criteria are usually adopted: tag reading delay and reader energy consumption [5]. As RFID reader and tag always communicate over a shared wireless channel, it is very easy to have signal collisions during a normal tag identification process when multiple tags exist in reader’s interrogation area. Signal collision results in query or data retransmission and eventually increases communication overhead and time delay of tag identification. Hence, an efficient tag collision arbitration mechanism is very important and critical for RFID systems to achieve effective performance. Existing RFID tag identification schemes can be classified into aloha-based solutions [3, 10, 12-13, 16, 21, 23-24] and tree-based solutions [1, 2, 4, 6-9, 14-15, 17-20, 22]. In aloha-based schemes, a reader estimates the number of tags in its interrogation area and broadcasts the total number of timeslots to each tag. Then each RFID tag randomly selects its own timeslot to transmit its ID without knowing which timeslots have been selected by other tags. By distributing tag responses to distinct timeslots instead of getting all tag responses at the same time, aloha-based schemes effectively reduce the probability of signal collision. However, aloha-based schemes have tag starvation problem in which certain tags may not

Radio Frequency Identification (RFID) systems consist of Electric Tags, or transponders and RF tag readers, or transceivers. Auto-tags of the RFID system have the unique ID feature and are capable of carrying information, which adds the tags more capability of which could be read only or read/write. RFID systems are now being used by more and more organizations connected with management, tracing, and control. The purpose of this study was to develop a information protection system (named PC-guard) using systems engineering and RFID technology. The login verification code can be notified in advance by using the PC-guard system because every PC user having their own Auto-tag will be checked with PC RFID reader. The information in the PC will be protected with RFID and the vibration sensor as the PC be turned on and be invaded. The development of this system using Blanchard and Fabrycky's procedure intends to bring the advantages of time saving and reduced risk using RFID technology. The developmental test and evaluation in the RFID lab had been done. The test results show that the PC-guard system can be operated well to protect the information in the PC with an active RFID tag and a PLC procedure with vibration sensor.

In this paper, we focus on configuring a low cost RFID (Radio Frequency IDentification) system with less RFID readers and low density RFID tag textiles for stable and accurate self-localization for an omni-directional mobile robot. An RFID system using multiple RFID readers and high density RFID tags has already been applied to an indoor mobile robot self-localization. However, the system production cost is relatively high. To reduce the production cost of the system while maintaining the self-localization performance, we redesign two new RFID systems configured with 20 RFID readers and 5 RFID readers enlarging the size of an RFID reader antenna. Particularly, a new likelihood function of the tag detection with the redesigned large size RFID reader antenna is proposed for Monte Carlo Localization (MCL). Furthermore, we come up with a novel arrangement of RFID tags installed in a hexagon pattern. The new arrangement of ID tags enables both low cost ID tag installation and high performance of self-localization. We examine the performances of robot self-localization with less RFID readers and lower density RFID tags installed on the floor based on MCL(Monte Carlo localization). The simulation demonstrates the validity of our proposed configuration of the RFID based self-localization.

The dynamic frame slot ALOHA (DFSA) algorithm is a typical anti-collision. For the shortcomings of DFSA algorithm, this paper presents an improved algorithm - IDFSA. On the one hand, IDFSA algorithm to improve the label estimation algorithm, so as to achieve dynamic adjustment. On the other hand, through the analysis of mathematics, the new grouping of labels is improved, and the phenomenon of landslide is improved. The simulation results show that the throughput of IDFSA algorithm is higher, and the total operations time is less. RFID (radio frequency identification, RFID) is widely used in logistics, identification, anti-theft and other fields. A traditional RFID system mainly includes two parts: the reader and the tag. In the case of the number of tags more dense, the reader must use the anti-collision to identify the individual tags. So, anti collision algorithm is very important in multi label application field. Tag anti-collision protocols (1) can be categorized into two groups: probabilistic anti-collision methods and deterministic anti-collision methods. The probabilistic anti-collision methods are Aloha-based protocols (2) such as pure Aloha protocol, Slotted ALOHA (SA) protocol, Framed Slotted ALOHA (FSA) protocol and Dynamic Framed Slotted ALOHA (DFSA) (3, 4) protocol. In this paper, an improved dynamic frame slot ALOHA (IDFSA) algorithm is proposed. 2. Related work Frame slotted ALOHA algorithm will be a plurality of time slots set as a frame, for a fixed frame length, when the tag number is less than the length of the frame appears waste the time slot, when the frame length is less than or equal to the number of tags conflict too frequent . In view of this situation, according to the number of tags in the reader range, dynamic adjustment of the next frame length, by a decrease or increase the length of the frame, you can solve the slot waste and tag identification time increased, this method is called dynamic frame slotted ALOHA (DFSA). The analysis of DFSA algorithm shows that the throughput of the system is mainly determined by the estimation of the number of tags and the adjustment of the frame length. The estimation of the number of tags plays a key role in the performance of the algorithm. At present, there are three kinds of label estimation algorithms, Vogt, Schoute and Lowbound

Sensor networks as well as radio frequency identification (RFID) systems are among the hyped technologies nowadays. A lot of research efforts have been spent to develop standards, middleware and applications. The industry has already made large investments to foster the adoption of these technologies, consequently pushing the development, and already deploying the resulting technologies in different domains. However, the addressed technologies are still very young; best practices as well as standards are expected to frequently change, as new demands arise when using the technologies in everyday life. Because of this, middleware systems are expected to undergo frequent redesigns as well, requiring well-suited design paradigms to avoid a software engineering nightmare. We therefore propose an agent-based middleware for sensor networks and RFID systems. This middleware will meet the challenges for having a robust, adaptable and flexible middleware, which is, moreover, easily extensible to cope with expected re-engineerings and changes while maintaining a clear and elaborate design.

There are many protocols proposed for protecting Radio Frequency Identification (RFID) system privacy and security. A number of these protocols are designed for protecting long-term security of RFID system using symmetric key or public key cryptosystem. Others are designed for protecting user anonymity and privacy. In practice, the use of RFID technology often has a short lifespan, such as commodity check out, supply chain management and so on. Furthermore, we know that designing a long-term security architecture to protect the security and privacy of RFID tags information requires a thorough consideration from many different aspects. However, any security enhancement on RFID technology will jack up its cost which may be detrimental to its widespread deployment. Due to the severe constraints of RFID tag resources (e.g., power source, computing power, communication bandwidth) and open air communication nature of RFID usage, it is a great challenge to secure a typical RFID system. For example, computational heavy public key and symmetric key cryptography algorithms (e.g., RSA and AES) may not be suitable or over-killed to protect RFID security or privacy. These factors motivate us to research an efficient and cost effective solution for RFID security and privacy protection. In this paper, we propose a new effective generic binary tree based key agreement protocol (called BKAP) and its variations, and show how it can be applied to secure the low cost and resource constraint RFID system. This BKAP is not a general purpose key agreement protocol rather it is a special purpose protocol to protect privacy, un-traceability and anonymity in a single RFID closed system domain.

Radio Frequency Identification (RFID) has become widespread thanks to its important advantages over traditional identification technologies, like barcodes. Compared to this technology, RFID is, in fact, able to cover larger distance and does not require line-of-sight, that represent important improvements in the considered field of application. An RFID system is formed by a set of n tags, that represent clients in the identification process, and a tag reader, that is the identification server. Each tag is associated with an identifier (ID), that must be transmitted to the reader upon receipt of a suitable identification query. Tags can be active, i.e. provided with an independent power supply (like a battery), or passive. In the latter case, tags depend on energy provided by the tag reader through its queries (Want, 2006). For this reason, active tags can have some data processing ability, while passive tags are limited to doing only elementary operations and replying to the reader’s queries. An important issue in Radio Frequency Identification systems concerns the reading of colocated tags, that must be managed through suitable Medium Access Control (MAC) protocols, specifically designed for low power devices. Efficiency of MAC protocols for RFID systems directly influences the time needed by the tag reader for completely identifying a set of co-located tags, so it has great impact on the whole system performance. A deep analysis of the MAC technologies adopted in RFID is the aim of this chapter. We denote by Ttot(n) the time needed by the tag reader for completely identifying a set of n tags. Under ideal conditions, it should be Ttot(n) = nTpkt, where Tpkt is the time needed to transmit one identification packet. However, in order to ensure collision-free transmission to each tag, a MAC protocol is needed that, inevitably, produces a time waste with respect to the ideal condition. The time actually needed for identification depends on several factors, like the technology adopted, the working frequency, etc. So, RFID systems can exhibit very different reading rates, typically ranging between 100 Tag/s and 1000 Tag/s. The most common MAC protocols used in RFID systems can be grouped into two classes: deterministic protocols and stochastic protocols. Deterministic protocols basically coincide with tree traversal algorithms: all RFID tags form a binary tree on the basis of their identifiers, and the reader explores the tree in a systematic way, by repeating queries based on bit masks. Randomness is only in the tree structure (due to the choice of the co-located tag set), while the algorithm execution is pre-determined. Stochastic MAC protocols are instead based on the framed slotted Aloha (FSA) algorithm, that requires each tag to make a constrained pseudo-random choice of an integer number in order to reduce the probability of collisions.