Dissertations / Theses on the topic 'Anti-collision protocol'

Radio Frequency Identification (RFID) is a wireless technology that has replaced barcodes. This technology is used in today’s world to track assets and people. An RFID system consists of three components: the tag, the reader, and the middleware. The RFID tag stores data, the reader is used to identify the data stored in the tag or write data to the tag, and the RFID middleware is the application that connects the data that the reader obtains from the tag with the company inventory or database. Unlike barcode readers, an RFID reader is capable of reading multiple tags located in its range. When this occurs, the probability of tag collision at the reader’s end is high. To avoid tag collision, anti-collision protocols are used. Slotted Aloha is one of the main anti-collision protocols used with RFID. This thesis proposed a mathematical model and a simulator to analyze the performance of the Slotted Aloha protocol without interference. Tag detection is directly related to tag signal strength detected by the reader. Radio Frequency signals behave differently when different objects are present in the environment. For example water absorbs radio signals. When water is present in the environment, tag detection will not be successful, since radio signals will be absorbed by the water. Therefore, water is considered an interference factor in tag detection. This thesis also proposed a mathematical model and a simulator to analyze the performance of the Slotted Aloha protocol with interference. A comparison of both sets of results shows that the proposed mathematical model and the simulator are accurate. Results of the analysis show that the time required to identify tags with interference is longer than the time required to identify tags without interference.
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science.

Over the years, RFID (radio frequency identification) technology has gained popularity in a number of applications. The decreased cost of hardware components along with the recognition and implementation of international RFID standards have led to the rise of this technology. One of the major factors associated with the implementation of RFID infrastructure is the cost of tags. Low frequency (LF) RFID tags are widely used because they are the least expensive. The drawbacks of LF RFID tags include low data rate and low range. Most studies that have been carried out focus on one frequency band only. This thesis presents an analysis of RFID tags across low frequency (LF), high frequency (HF), and ultra-high frequency (UHF) environments. Analysis was carried out using a simulation model created using OPNET Modeler 17. The simulation model is based on the Basic Frame Slotted ALOHA (BFSA) protocol for non-unique tags. As this is a theoretical study, environmental disturbances have been assumed to be null. The total census delay and the network throughput have been measure for tags ranging from 0 to 1500 for each environment. A statistical analysis has been conducted in order to compare the results obtained for the three different sets.

Radio frequency identification (RFID) is used to identify, track, and manage tagged animate or inanimate objects automatically using wireless communication technology. RFID is similar to existing barcode identification, but it has additional features. RFID has the capability of scanning multiple objects at the same time. This improves productivity by reducing the time taken to identify objects. RFID has the capability to read through opaque material without requiring line of sight, thus saving time in processing that would otherwise require upwardfacing objects. RFID is extremely appropriate for applications that require tags to be read at large distances. RFID readers and tags come in various sizes and forms, thus permitting this type of technology to be used in a broad variety of situations. Some tags are blast-proof, some tags are the size of lunch boxes, and some are smaller than a grain of rice. Also, RFID tags can be reprogrammable, thus reducing cost. As RFID technology continues to grow rapidly, different issues and challenges are presented. A serious concern faced by RFID technology is the collisions that occur during communication. This is considered one of the immense challenges in RFID development because collisions limit system performance significantly. Collisions bring extra delay, a waste of bandwidth, and extra energy consumption to the interrogation process of RFID. Delays that arise due to collisions in RFID systems create significant issues and challenges to applications that require high inventory speed. Therefore, RFID system designers and researchers need to simulate these different environments before deployment to correctly identify various factors, such as the number of RFID readers needed, where to place these readers, etc. The simulator developed in this research is called the RFID Simulator. It was developed completely from scratch to evaluate the performance of Slotted Aloha and EPCglobal Class-1 Generation-2 protocols for RFID systems. The RFID Simulator was designed to replicate a reallife RFID environment. It can be used to imitate hardware and has the capability to calculate the delay to any number of RFID tags, which is not possible with real-life RFID systems. As a result, the performance of RFID systems can be improved significantly. The integrity of the simulator was verified by comparing its results with mathematical analysis and experimental results. The RFID Simulator is a complete, all-in-one package, designed with the ability to be extended to a commercial RFID simulator, which will help immensely in the future development of RFID.
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science.

Wireless communication systems are increasingly being used in industries and infrastructures since they offer significant advantages such as cost effectiveness and scalability with respect to wired communication system. However, the broadcast feature and the unreliable links in the wireless communication system may cause more communication collisions and redundant transmissions. Consequently, guaranteeing reliable and efficient transmission in wireless communication systems has become a big challenging issue. In particular, analysis and evaluation of reliable transmission protocols in wireless sensor networks (WSNs) and radio frequency identification system (RFID) are strongly required. This thesis proposes to model, analyze and evaluate self-configuration algorithms in wireless communication systems. The objective is to propose innovative solutions for communication protocols in WSNs and RFID systems, aiming at optimizing the performance of the algorithms in terms of throughput, reliability and power consumption. The first activity focuses on communication protocols in WSNs, which have been investigated, evaluated and optimized, in order to ensure fast and reliable data transmission between sensor nodes. The second research topic addresses the interference problem in RFID systems. The target is to evaluate and develop precise models for accurately describing the interference among readers. Based on these models, new solutions for reducing collision in RFID systems have been investigated.

Radio Frequency Identification (RFID) is a powerful emerging technology widely used for asset tracking, supply chain management, animal identification, military applications, payment systems, and access control. Over the years, RFID has emerged as a popular technology in various industries because of its ability to track moving objects. As RFID is becoming less expensive and more robust, many companies and vendors are developing tags to track objects. Multiple vendors manufacture RFID tags worldwide. Therefore, it is quite possible that they manufacture tags with the same identification code (ID) as vendor ID code data sets may not be synchronized or may be subject to tag id errors. Due to this drawback, there is the possibility that non-unique tags exist along with unique tags in the same RFID system. As existing implementations optimize the performance of RFID systems performance based on the assumption of unique tags, it is important to study the effect of non-unique tags on RFID systems. This thesis focuses on a formal analysis of the Basic Frame Slotted ALOHA (BFSA) Muting RFID system with non-unique tags. An RFID network was modeled with OPNET Modeler 14.5. An evaluation model was built to measure the total census delay, optimal frame size, and network throughput for an RFID network based on a BFSA protocol for non-unique tags and support for muting. The evaluation results are in agreement with results obtained from the evaluation of a similar model for unique tags [Kang08]. Comparing total census delay for unique and non-unique tags for variable frame sizes showed an increase in total census delay with an increase in the number of tags. Comparing minimum network throughput, mean network throughput, and maximum network throughput for unique and non-unique tags for variable frame sizes showed a decrease in network throughput with an increase in the number of tags.

Radio frequency identification (RFID) systems are increasingly used for a wide range of applications from supply chain management to mobile payment systems. In a typical RFID system, there is a reader/interrogator and multiple tags/transponders, which can communicate with the reader. If more than one tag tries to communicate with the reader at the same time, a collision occurs resulting in failed communications, which becomes a significantly more important challenge as the number of tags in the environment increases. Collision reduction has been studied extensively in the literature with a variety of algorithm designs specifically tailored for low-power RFID systems. In this study, we provide an extensive review of existing state-of-the-art time domain anti-collision protocols which can generally be divided into two main categories: 1) aloha based and 2) tree based. We explore the maximum theoretical gain in efficiency with a 2-fold frequency division in the ultra-high frequency (UHF) band of 902-928 MHz used for RFID systems in the United States. We analyze how such a modification would change the total number of collisions and improve efficiency for two different anti-collision algorithms in the literature: a relatively basic framed-slotted aloha and a more advanced reservation slot with multi-bits aloha. We also explore how a 2-fold frequency division can be implemented using analog filters for semi-passive RFID tags. Our results indicate significant gains in efficiency for both aloha algorithms especially for midsize populations of tags up to 50. Finally, we propose two modifications to the Q-algorithm, which is currently used as part of the industry standard EPC Class 1 Generation 2 (Gen 2) protocol. The Q-Slot-Collision-Counter (QSCC) and Q-Frame-Collision-Counter (QFCC) algorithms change the size of the frame more dynamically depending on the number of colliding tags in each time slot with the help of radar cross section technique whereas the standard Q-algorithm uses a fixed parameter for frame adjustment. In fact, QFCC algorithm is completely independent of the variable "C" which is used in the standard protocol for modifying the frame size. Through computer simulations, we show that the QFCC algorithm is more robust and provide an average efficiency gain of more than 6% on large populations of tags compared to the existing standard.

Les techniques les plus recentes en matiere de transmission de donnees sont appliquees aux systemes anti-collision pour grues a tour. En introduction nous presentons l'architecture de ces systemes dans l'etat de l'art, en precisant les contraintes auxquelles ils sont soumis. Dans une premiere partie, a partir d'une analyse des faiblesses des systemes actuels, nous developpons entierement un reseau hertzien assurant l'echange fiable d'informations de position entre les grues d'un chantier, et comprenant un protocole specifique adapte a l'aspect temps reel. En deuxieme partie sont abordes les problemes de communication sur la grue elle-meme, entre unite centrale, capteurs et actionneurs. Nous justifions le choix d'un bus de terrain pour assurer de maniere plus fiable et plus souple ces echanges. La mesure de vitesse de rotation, est un parametre essentiel pour le controle de certaines grues, ceci nous conduit a developper un capteur de vitesse a effet gyroscopique. Nous evaluons en conclusion les benefices apportes au systeme dans son ensemble avant de discuter des perspectives d'extension de notre architecture.

碩士
國立宜蘭大學
多媒體網路通訊數位學習碩士在職專班
101
When multiple tags simultaneously transmit their IDs to Reader in the RFID system, the signals will collide. This collision will disturb the reader’s identification process. In this thesis, we based on Counter-based protocols, BT and ABS, it was mainly developed to reduce collision condition. Its protocol does not rely on tag IDs for the splitting, and it has the stable property that its performance is not affected by the ID distribution or the ID length. At the parallel transmission condition, this thesis develops multi-channel type protocol for BT and ABS to improve the performance of counter based protocols.

碩士
國立成功大學
電信管理研究所
100
In recent years, radio frequency identification (RFID) has become an important infrastructure technology. It is a fast, secure, and efficient identification procedure that influences many various applications, such as supply chain management, toll-payment, libraries, e-passports, and shopping. RFID technology works in a wireless environment in which a reader has to identify many tags at the same time. This usually leads to collisions and unidentified data in reading process. Therefore, one always strives to solve such an anti-collision problem. However, most research effort is usually limited to the stage of system simulation. Although the simulation is actually performed in accordance with the protocol, it is still not enough to explain the reliability in the real work. This research builds a RFID platform, including work of anti-collision algorithm, programs of compilation and burning, method of data collecting, and so on. We select a well-known algorithm (Schoute’s Method) to implement and compare with a base line algorithm (low bound method). The experiment results are quit consistent with that from other works of research. Thus, the experiment platform we built is reliable in actual work. Future research can focus on more efficient anti-collision algorithms, and use this experiment platform to verify the algorithms.

碩士
國立臺灣科技大學
資訊工程系
97
RFID is an automatic identification technology in reader and tags communication by using RF wave. In the RFID system, due to there are usually more than one tags in the interrogation zone of reader, when multiple tags transmitted their data to the reader simultaneously, signal will be collided because the reader and tags communicate over a shared wireless channel, the reader may not recognize all tags due to the collisions. Therefore, how to reduce collisions is a significant issue for tag-identification in RFID system. New Enhance Anti-collision Algorithm (NEAA) is a novel anti-collision algorithm of tag ID identification in RFID system. Since the tag ID in RFID system is a unique binary number, NEAA use the characteristic of the tag ID is unique to identify multiple tags simultaneously. This paper proposes an anti-collision algorithm to improve the performance of NEAA by using TBCT (Two Bit Collision Timeslot) to increase the probability of M-readable. The proposed algorithm can also reduce the number of collisions and the identification latency.

碩士
中華大學
電機工程學系碩士班
94
In this paper, a digital anti-collision system circuit design for Radio Frequency Identification (RFID) tag is presented completely. This system implements the “Slotted Random Aloha” anti-collision algorithm. Hence, there are two functions commended to tags. One is using random number system to do time-division multiplexing (TDM) ; the other is data linking frequencies can choose by readers. The proposed anti-collision system circuit not only enhances functions to tags, but also speeds up the identification. Meanwhile, it reduces the error detection and the power consumption. We implemented the design on FPGA board ALTERA APEX20KE EP20K1500EBC652-1X with ALTERA QuartusⅡ tools for the waveform simulation. At last, the simulation results and measurement results were test and verified, compatible with the EPC Class-1 Generation-2 UHF RFID Protocol [1] successfully.

碩士
國立臺灣科技大學
資訊管理系
98
Radio Frequency Identification (RFID) is a contactless automatic identification technology which communications between readers and tags via a shared wireless channel. With the ability of contactless identification, RFID has been adopted in several practical applications, such as logistics, inventory control, and supply chain management. In the supply chain process, the items which put together usually have continuous tag IDs. When a reader intends to gather all IDs from numerous existing tags, the tag-to-reader response may collide with each other and result in an identification failure called signal collision. This phenomenon will greatly degrade the tag recognition efficiency. To solve this problem, we design an efficient tag identification protocol for better tag recognition efficiency. A k-ary tree based abstract is adopted in our proposed protocol, called k-ary Tree-based Anti-collision Scheme (k-TAS), as an underlying architecture for collision resolution. In addition, we construct a supply chain network simulation process to evaluate the performance of our proposed RFID anti-collision protocol and other existing ones. The performance evaluation shows that our proposed tag identification protocol outperforms the existing RFID anti-collision schemes in terms of the identification delay and communication overhead.

碩士
國立東華大學
資訊工程學系
99
Radio frequency identification (RFID) system consists of radio tags, readers, and the backend database system that associates RFID tag data collected by readers for verification or special need. A Reader communicates with tags at distance through wireless transmission. Many manufacturers see the intended applications of RFID technology, and deploy RFID in inventory control, distribution industry and supply chain management. As far, there are already many concrete applications using RFID, e.g., inventory control, distribution industry and supply chain management. However, a so-called tag collision problem in RFID system happen when multiple tags respond to a reader simultaneously and the reader cannot differentiate these tags correctly. Tag collisions will degrade identification efficiency, and this unreliable identification compromises the usefulness of RFID system. There are two major types of anti-collision protocols. One is ALOHA-based protocol and the other is tree-based protocol. ALOHA-based protocol reduces the tag collisions, while it has the starvation problem (a tag cannot be identified for a long time). To address such problem, two tree-based protocols- binary tree (BT) protocol and the query tree (QT) protocol- were accordingly proposed. In this thesis, we propose two QT based protocols. Recently, a RN16QT was proposed, which used a RN16 random number as the temporary ID of tag. It successfully reduces the time consumption for tag identification. However, the tag collision still occurs due to the short length of RN16. We propose an effective RN16QT (ERN16QT) to enhance RN16QTA. Our ERN16QT can also address the similar EPC. A ternary tree is impossible in QT protocol, but it brings about the optimum performance for tag identification. We propose a practical ternary QT protocol to efficiently identify a binary EPC.

碩士
國立東華大學
資訊工程學系
99
Radio frequency identification (RFID) system consists of radio tags, readers and the backend database system. Readers communicate with tags through wireless transmission to identify a tag. RFID has various application services, e.g., inventory control, distribution industry and supply chain management. Due to the fast and successful deployment of large scale RFID system, this results in a situation that multiple readers are located in a small area. This multi-reader RFID environment is referred to as dense reader environment (DRE). In DRE, multiple readers are operating in proximity of one another. Therefore, several readers interrogate at the same time in the vicinity. This DRE makes the RF channel noisy such that readers cannot successfully identify tags. This is so-called reader collision problem. Up to date, there are some techniques to solve the reader collision problem, which can be categorized into TDMA, FDMA, and SDMA, but the problem of reader collision cannot be completely solved by FDMA. In this thesis propose two reader anti-collision protocol based on SDMA and TDMA. By using the five sweeping-beam antenna in a reader (SDMA), we carefully sett the initial angles of all readers’ smart antennas and sweeping 360 degrees simultaneously, we could successfully identify tags and solve the collision problems in dense environments. At this time, we use five different angles. A five coloring theorem is used to select the initial angles of readers. On the other hand, TDMA is to use different timeslots for the reader accessing. However, it may have the following weaknesses: each reader has long idle time if the number of time slots, and the other is asynchronous problem. We adopt the (k, d)-coloring theorem to solve this two weakness.

博士
國立中央大學
資訊工程研究所
98
In the RFID system, the reader identifies tags by interrogating their IDs through a shared wireless communication channel. Collisions occur when multiple tags transmit their IDs to the reader simultaneously, degrading the performance of tag identification. How to reduce tag collisions to speed up the identification is thus important. There are several anti-collision protocols proposed for dealing with tag collisions. They can be categorized into two classes: ALOHA-based protocols and tree-based protocols that include deterministic tree-based and probabilistic counter-based subclasses of protocols. In this dissertation, we propose two probabilistic counter-based (“Adaptive Splitting and Pre-Signaling” and “Parallel Splitting”) protocols and one deterministic query tree-based (“Parallel Reverse Response”) anti-collision protocol. 1) “Adaptive Splitting and Pre-Signaling” protocol uses the idea of “Adaptive Splitting” scheme to estimate the number K of oncoming identification tags and split them into K proper subgroups, besides “Pre-Signaling” scheme is proposed to reduce the number of messages sent between the reader and tags by detecting the number of tags (null, one or multiple tags) with counter=1 previously. 2) “Parallel Splitting” protocol uses the idea of “parallel splitting” scheme to split the unidentified tags concurrently instead of only the tags with counter = 0 as in the ISO 18000-6B standard. It also utilizes “adaptive identification-tree height adjustment” scheme to adjust the number of leaf nodes of identification tree to approach the number of tags. 3) “Parallel Reverse Response” protocol integrates the ideaof “parallel prefix matching” and “Parallel Two Sub-carriers Response” schemes to let the tags with prefix ID matching the request bit string S or complementary of S be arranged to respond in two sub-carriers simultaneously in order to speed up RFID tagidentification. We analyze and simulate these three proposed protocols and compare them with related protocols to demonstrate their advantages.

碩士
華梵大學
工業工程與經營資訊學系碩士班
97
Radio Frequency Identification (RFID) is an automatic identification system for objects, which consists of readers、tags and host application system. A tag has a unique identification number (ID), and a reader communicates with tags which attached to objects over a shared wireless channel for tag identification. When reader interrogates tags within the reader’s range, and multiple tags transmit their IDs simultaneously, the tag-to-reader signals occur collision. Therefore, tag collision disturbs the reader’s identification efficiency. The tag anti-collision protocol is an important issue for fast recognizes objects. This research is major reviewed tag anti-collision protocols that be proposed recently. Tag anti-collision protocols can be grouped into two broad categories：Tree-based protocols and Aloha-based protocols. The research contains thirteen tag anti-collision protocols, seven of them are on the basis of Tree-based protocol, and the others are on the basis of Aloha-based protocol. This research classified these protocols by thier characteristic, and also provides a comparison between reviewed protocols, advantages and shortcomings, and suitable condition for use. This review could provide the basis for developing more efficient and perfect tag anti-collision protocols.

博士
國立臺灣科技大學
資訊管理系
98
In Radio Frequency Identification (RFID) systems, the reader identifies tags through communication over a shared wireless channel. When multiple tags transmit their IDs simultaneously, their signals collide, increasing the identification delay. Therefore, many previous anti-collision algorithms, including an adaptive query splitting algorithm (AQS) and an adaptive binary splitting algorithm (ABS), focused on solving this problem. The reader, using AQS or ABS, reserves information obtained from the last process of tag identification in order to fast re-identify the staying tags. Using this information, AQS and ABS can successfully avoid collisions among staying tags. From the previous study, ABS may have the shorter identification delay, while AQS requires lighter tag specification. We propose three techniques based on ABS and AQS to accelerate identifying RFID tags, i.e., Blocking technique, Pairing technique, and Symbolic Response technique. First, because AQS and ABS let staying tags collide with arriving tags that newly appear in the current frame and were not recognized in the last frame, we propose Blocking technique to successfully prevent staying tags from be collided by arriving tags. After successfully dividing tags into arriving tags and staying tags, to accelerate identifying staying tags, we not only use Blocking technique but also further adopt Pair technique, which allows each pair of the tags recognized in the last frame to transmit their IDs simultaneously in the current frame. Then, we also discover staying tags do not need to respond complete IDs when arriving tags and staying tags are divided, because the algorithms already retained these IDs obtained from the last frame. Thus, we propose Symbolic Response technique to allow each staying tag to respond a symbolic response replacing the tag ID when re-identifying these recognized tags. We adopt Blocking technique on ABS and AQS to respectively propose Single resolution blocking ABS algorithm (SRBBT) and Single resolution blocking AQS algorithm (SRBQT), but they still identify staying tags one by one. Then, therefore, we adopt Pair and Blocking technique to propose Pair resolution blocking ABS algorithm (PRBBT) and Pair resolution blocking AQS algorithm (PRBQT). Moreover, PRBQT couples staying tags by sending a query that includes two ID prefixes to reduce the time at identifying staying tags. That means that PRBQT prepares two ID prefixes for each pair of staying tags. Thus, we further propose Enhanced pair resolution blocking AQS algorithm (EPRBQT), which also adopts the same Blocking technique as PRBQT, but uses a different Pair technique from it. EPRBQT uses a query that includes only one ID prefix to couple staying tags; thus, it has fewer transmitted bits compared to PRBQT. Finally, we use Symbolic response technique and respectively modify SRBBT, SRBQT, PRBBT, and PRBQT to develop SSRBBT, SSRBQT, SPRBBT, and SPRBQT, which allow each staying tag to respond a symbolic response replacing the tag ID when re-identifying these recognized tags. In this presentation, the performance of all algorithms is formally analyzed. And then, the analytic and simulation results show that our algorithms are better than ABS and AQS. The blocking algorithms can avoid more collisions than the non-blocking algorithms. And then, by Pair technology, the pairing blocking algorithms reduce about the half time at identifying staying tags compared with non-pairing blocking algorithms. Moreover, using Symbolic Response technology in blocking algorithms, this kind of algorithms successfully reduces much transmission time. Finally, because SPRBBT combines three technologies, i.e., blocking, pairing, and symbolic response, it shows the best performance.