Missing Tag Identification Research Articles

Revisiting RFID Missing Tag Identification: Theoretical Foundation and Algorithm Design

Revisiting RFID Missing Tag Identification: Theoretical Foundation and Algorithm Design

A Collision Reconciling-Based B-Ary Tree-Splitting Missing Tag Identification Protocol

A Collision Reconciling-Based <i>B</i>-Ary Tree-Splitting Missing Tag Identification Protocol

An Efficient Early-breaking-estimation and Tree-splitting Missing RFID Tag Identification Protocol

Retailers grapple with inventory losses primarily due to missing items, prompting the need for efficient missing tag identification methods in large-scale RFID systems. Among them, few works considered the effect of unexpected unknown tags on the missing tag identification process. With the presence of unknown tags, some missing tags may be falsely identified as present. Thus, the system’s reliability is hardly guaranteed. To resolve these challenges, we propose an efficient early-breaking-estimation and tree-splitting-based missing tag identification (ETMTI) protocol for large-scale RFID systems. ETMTI employs innovative early-breaking-estimation and deactivation methods to swiftly handle unknown tags. Subsequently, a tree-splitting-based missing tag identification method is proposed, employing a B-ary splitting tree, to rapidly identify missing tags. Additionally, a bit-tracking response strategy is implemented to reduce processing time. Theoretical analysis is conducted to determine optimal parameters for ETMTI. Simulation results illustrate that our proposed ETMTI protocol significantly outperforms benchmark methods, offering a shorter processing time and a lower false negative rate.

An Efficient Missing Tag Identification Approach in RFID Collisions

Radio frequency identification technology has been widely used to verify the presence of items in many applications such as warehouse management and supply chain logistics. In these applications, the challenge of how to timely identify the missing tags (namely tag searching or missing tag identification) is a key focus. Existing missing tag identification solutions have not achieved their full potentials because collision slots have not been well explored. In this paper, we propose an approach named collision resolving based missing tag identification (CR-MTI) to break through the performance bottleneck of existing missing tag identification protocols. In CR-MTI, multiple tags are allowed to respond with different binary strings in a collision slot. Then, the reader can verify them together by using the bit tracking technology and particularly designed string, thereby significantly improve the time efficiency. CR-MTI also reduces the number of messages transmitted by the reader using customized coding. We further explore the optimal parameter settings to maximize the performance of our proposed CR-MTI. Extensive simulation results show that our proposed CR-MTI outperforms prior art in terms of time efficiency, total executive time and communication complexity.

Missing Unknown Tag Identification Protocol Based on Priority Strategy in Battery-less RFID System

Radio frequency identification technology by transmitting radio waves to the target area and attaching to the object battery-free RFID tags. It can accomplish the fast, timely, and accurate acquisition of the relevant data of the object without touching the identified object. In practical applications, there may be problems where products that have not been warehoused are missing, which we call missing unknown tag problem. The existing missing tag identification methods are not well suited to the scene, and the missing tag identification method containing unknown tags only takes into account the problem of known tags and unknown tags appearing in the same area, and cannot solve the problem of these missing unknown tags. Therefore, we propose a priority based strategy for missing unknown tag identification (PMUTI), which improves the identification process by means of the priority strategy. The method of sequential marking for unknown tags that have been missing is convenient for warehouse managers to make quick judgment and processing. The experimental results show that the PMUTI outperforms existing methods.

Efficient collision-slot utilization for missing tags identification in RFID system

Radio Frequency Identification (RFID) technology has become one of the most promising building blocks in future IoT-enabled applications, including supply chain management, intelligent logistics, inventory control, etc.. This paper studies the fundamental problem of completely identifying missing tags in RFID systems. The most important measure for missing tag identification is to minimize the execution time. Most of the existing missing tag identification schemes compare the singleton slot in the expected mapping vector with the actual mapping vector observed by a reader to determine whether the corresponding tag is missing or not. However, they are of low efficiency because the useless collision slots account for a large proportion of the slots in a time frame. This paper proposes a Collision Unfolding-based Missing tag Identification (CUMI) protocol, which applies a novel indicator vector and Manchester coding techniques for transforming parts of abandoned collision-slots into valuable slots, thereby the utilization of slots in a time frame gets a promotion. However, CUMI requires transmitting long indicator vectors to tags, which incurs too much communication overhead. To address this problem, we propose an Enhanced Collision Unfolding-based Missing tag Identification (ECUMI) protocol to further compress the length of indicator vectors at the expense of longer tag responses. Throughout the simulation, we find that ECUMI has a higher time efficiency in missing tag identification than CUMI does. Extensive simulation results reveal that CUMI and ECUMI outperform the state-of-the-art missing tag identification protocols by at least 1.02× and 1.8× in the single-reader scenario, respectively.

Efficient and accurate identification of missing tags for large-scale dynamic RFID systems

The future real-world applications is bound up with Radio frequency identification (RFID) technology as it develops dramatically fast, especially in the field of warehouse management and inventory control, etc. In such applications, identifying missing tags to determine which goods are missing is an important issue. However, since only static scenarios with no new tag movement are considered, existing missing tag identification protocols hardly work well in more common dynamic scenarios where there are tags entering the system or missing frequently. In highly dynamic RFID systems, identifying missing tags becomes more challenge under the interference of unknown tags. Existing methods suppress this interference by filtering unknown tags, which is time-consuming and inefficient. In this paper, for high dynamic RFID systems, we propose an efficiently and accurately protocol HDMI to identify missing tags. By combining the reply slot location of the tags and the reply bits, HDMI identifies missing tags and filters the unknown tags simultaneously, which maximizes the slot utilization. We also optimize the setting of key parameters to reduce execution time while ensuring recognition accuracy. Simulation results show that, compared with state-of-art protocols, HDMI has a higher accuracy rate and better time efficiency in identifying missing tags.

Modeling and analyzing RFID Generation-2 under unreliable channels

EPCglobal Class-1 Generation-2 (RFID Generation-2) is a wireless communication system in Internet of Things. The models and analyses of RFID Generation-2 are important and have been reported. However, for usefulness and validity, existing models and analyses are mainly based on the assumptions that RFID runs in ideal wireless channels (no packet loss, no error code, and no capture effect). However, there are three co-existing these bad results (packet loss, error code, and capture effect) in the realistic channels, which means that the channels are unreliable. For obtaining comprehensive understanding of RFID Generation-2 performance to conduct relevant important researches, some models are developed for RFID Generation-2 under the unreliable channels. Meanwhile, four feasible methods for calculating the probabilities of those bad results (as models parameters) are given. After validating accuracy of the models through extensive simulation experiments and their fitness for an instance, these models are used to analyze impacts of the parameters on time efficiency, and obtain some key sensitivity factors promoting efficiency. Furthermore, analytical results demonstrate that the analyses considering those co-existing bad results are basis for the researches of some fields such as the general tag identification, the blocked tags identification, the missing tag identification, and the effective hardware design.

Time-efficient Missing Tag Identification in an Open RFID System

Radio Frequency IDentification (RFID) technology has been widely used in missing tag identification to reduce the economic loss caused by theft. Although many advanced works have been proposed, they cannot work properly in an open RFID system with unexpected tags. That is because the unexpected tags may reply to the reader when it is the missing tags’ turn, such that the replies are mistakenly treated as the missing tags’, leading to failure to detect the missing tags. To solve the problem, this article proposes an order-based missing tag identification protocol (OMTI) that efficiently identifies all missing tags even with the presence of unexpected tags. The key of OMTI is that we dynamically assign each tag an exclusive slot rather than use random hashes in traditional design. Namely, OMTI off-line serializes all known tags in advance by assigning each of them a unique and continuous slot, on-line identifies missing tags by checking tags’ responses in each slot, and dynamically updates the slot assignment to ensure the high efficiency of the next execution. Besides, we enhance OMTI to make it embrace newly added tags and spread to the multi-reader case from the single one. The simulation results demonstrate that OMTI can significantly reduce the identification time compared to the state-of-the-art.

Missing Tag Identification in COTS RFID Systems: Bridging the Gap between Theory and Practice

With rapid development of radio frequency identification (RFID) technology, ever-increasing research effort has been dedicated to devising various RFID-enabled services. The missing tag identification, which is to identify all missing tags, is one of the most important services in many Internet-of-Things applications such as inventory management. Prior work on missing tag detection all rely on hash functions implemented at individual tags. However, in reality hash functions are not supported by commercial off-the-shelf (COTS) RFID tags. To bridge this gap between theory and practice, this paper is devoted to detecting missing tags with COTS Gen2 devices. We first introduce a point-to-multipoint protocol, named P2M that works in an analog frame slotted Aloha paradigm to interrogate tags and collect their electronic product codes (EPCs). A missing tag will be found if its EPC is not present in the collected ones. To reduce time cost of P2M resulted from tag response collisions, we further present a collision-free point-to-point protocol, named P2P that selectively specifies a tag to reply with its EPC in each slot. If the EPC is not received, this tag is regarded to be missing. We develop two bitmask selection methods to enable the selective query while reducing communication overhead. We implement P2M and P2P with COTS RFID devices and evaluate their performance under diverse settings.

Efficient missing tag identification in blocker-enabled RFID systems

Due to limited on-chip resources, RFID tags may blindly respond to any readers authorized or not, leading to privacy leakage when sensitive data are exposed. A feasible solution to this problem is deploying blocker tags that emulate and behave like the genuine tags. With this deployment, there is always a virtual tag produced by the blocker tag that responds to the reader when the genuine tag to be protected replies, resulting in irreconcilable collisions and thus preventing privacy-leakage. This paper studies the problem of missing tag identification in blocker-enabled RFID systems. Unlike existing work, the reader in this problem will always get the responses from blocker tags even the genuine tags are lost, which makes the existing solutions unavailable. To address this problem, we propose three efficient protocols. The first is a group-based protocol that splits the entire tag set into three subsets and separately deals with each of them in different ways. The second protocol is called collision-reconciled protocol that turns some useless collision slots into useful singleton slots, increasing slot availability and thereby reducing the execution time. The third protocol is a concurrent missing tag identification protocol that improves the time efficiency of missing-event detection by running grouping and missing identification in parallel rather than in sequence. Theoretical analyses and extensive simulations show that our protocols are far superior to benchmark. For example, our best protocol can improve the identification efficiency by a factor of 6.

A Review on Missing Tags Detection Approaches in RFID System

Radio Frequency Identification (RFID) system can provides automatic detection on very large number of tagged objects within short time. With this advantage, it is been using in many areas especially in the supply chain management, manufacturing and many others. It has the ability to track individual object all away from the manufacturing factory until it reach the retailer store. However, due to its nature that depends on radio signal to do the detection, reading on tagged objects can be missing due to the signal lost. The signal lost can be caused by weak signal, interference and unknown source. Missing tag detection in RFID system is truly significant problem, because it makes system reporting becoming useless, due to the misleading information generated from the inaccurate readings. The missing detection also can invoke fake alarm on theft, or object left undetected and unattended for some period. This paper provides review regarding this issue and compares some of the proposed approaches including Window Sub-range Transition Detection (WSTD), Efficient Missing-Tag Detection Protocol (EMD) and Multi-hashing based Missing Tag Identification (MMTI) protocol. Based on the reviews it will give insight on the current challenges and open up for a new solution in solving the problem of missing tag detection.

An Efficient Approach to Detecting Missing Tags in RFID Data Stream

RFID technology is a Radio frequency identification system that provides a reader reading the data item from its tag. Nowadays, RFID system has rapidly become more common in our life because of its autonomous advantages compared to the traditional barcode. It can detect hundreds of tagged items automatically at a time. However, in RFID, missing tag detection can occur due to signal collisions and interferences. It will cause the system to report incorrect tag’s count due to an incorrect number of tags being detected. The consequences of this problem can be enormous to business, as it will cause incorrect business decisions to be made. Thus, a Missing Tag Detection Algorithm (MTDA) is proposed to solve the missing tag detection problem. There are many other existing approaches has been proposed including Window Sub-range Transition Detection (WSTD), Efficient Missing-Tag Detection Protocol (EMD) and Multi-hashing based Missing Tag Identification (MMTI) protocol. The result from experiments shows that our proposed approach performs better than the other in terms of execution time and reliability.

Efficiently and Completely Identifying Missing Key Tags for Anonymous RFID Systems

Radio frequency identification (RFID) systems can be applied to efficiently identify the missing items by attaching them with tags. Prior missing tag identification protocols concentrated on identifying all of the tags. However, there may be some scenarios in which we just care about the key tags instead of all tags, making it inefficient to merely identify the missing key tags due to the interference of replies from the ordinary tags (i.e., nonkey tags). In this paper, we propose to investigate the problem of efficiently and completely identifying the missing key tags for anonymous RFID systems in which the tag privacy is required to be well protected. First, we propose a vector-based missing key tag identification protocol called VEKI. Then we propose an improved protocol called iVEKI, which consists of two phases: 1) ordinary tag deactivation and 2) missing key tag identification. The parameters of the proposed VEKI and iVEKI protocols are theoretically optimized to maximize the time efficiency. Finally, we conduct extensive simulations to evaluate the proposed VEKI and iVEKI protocols and the simulation results illustrate that they outperform other existing protocols in terms of execution time.

A Time-Efficient Pair-Wise Collision-Resolving Protocol for Missing Tag Identification

Radio frequency identification (RFID) technology has been employed in wide-raging application domains. In most RFID applications, time-efficient identification of missing tags is one of the most fundamental objectives, especially for asset management and anti-theft purposes. In this paper, we propose a time-efficient pair-wise collision-resolving missing tag identification (PCMTI) protocol for large-scale RFID systems. In the protocol, two novel strategies, i.e., the pair-reply and two-collision slot (i.e., a slot with two exact tag responses) resolving strategies, are proposed. The pair-reply strategy can verify two tags in one short response slot simultaneously, while the two-collision slot resolving strategy further increases the number of tags verified in each frame. Both theoretical analysis and simulated results are presented to demonstrate the superiority of the proposed PCMTI protocol, which is capable of outperforming the state-of-the-art comparative protocols with at least a 30% reduction in average identification time for verifying one tag.

Efficient and Reliable Missing Tag Identification for Large-Scale RFID Systems With Unknown Tags

Radio frequency identification (RFID), which promotes the rapid development of Internet of Things (IoT), has been an emerging technology and widely deployed in various applications such as warehouse management, supply chain management, and social networks. In such applications, objects can be efficiently managed by attaching them with low-cost RFID tags and carefully monitoring them. The missing objects, therefore, can be identified by the readers in the RFID system. Most of prior missing tag identification protocols consider the ideal scenario that all the tags’ IDs are known to the reader, which ignore that some tags with unknown IDs, called unknown tags, may be present in the system. In this paper, we investigate the problem of efficiently identifying the missing tags with a predefined reliability for large-scale RFID systems with unknown tags. We first propose a basic efficient and reliable missing tag identification protocol called B-ERMI. Then we propose an enhanced protocol called E-ERMI to further improve the efficiency. The parameters of our proposed ERMI protocols are optimized to minimize the execution time. We also conduct extensive simulations to evaluate the proposed ERMI protocols and the simulation results illustrate that the ERMI protocols outperform other existing ones.

Fast temporal continuous scanning in RFID systems

This paper studies the problem of temporal continuous scanning for large-scale RFID systems, which is an essential operation to keep the inventory up-to-date. The existing solutions need to execute unknown and missing tag identification protocols separately, which are of low time-efficiency because the unknown tags disturb the identification of missing tags and vice versa. To this end, we design a Fast Continuous Scanning (FCS) protocol based on the proposed multiple categories filter which can detect unknown tags and skip the empty and collision slots for improving the efficiency of missing tag identification. FCS is faster than the prior methods because the proposed filter is helpful to decreasing the interference between unknown and missing tags. We also investigate the optimization of the involved parameters to minimize the execution time. Extensive simulation results demonstrate that the proposed protocol outperforms the state-of-the-art solutions by saving 39% ∼ 58.5% of the execution time.

Fast and Reliable Detection and Identification of Missing RFID Tags in the Wild

Radio-frequency identification (RFID) systems have been deployed to detect and identify missing products by affixing them with cheap passive RFID tags and monitoring them with RFID readers. Existing missing tag detection and identification protocols require the tag population to contain only those tags whose IDs are already known to the reader. However, in reality, tag populations often contain tags with unknown IDs, called unexpected tags. These unexpected tags cause unexpected false positives, i.e. , due to them, missing tags are detected as present. We take the first step toward addressing the problem of detecting and identifying missing tags from a population that contains unexpected tags. Our protocol, RUN, uses standardized frame slotted Aloha for communication between tags and readers. It executes multiple frames with different seeds to reduce the effects of unexpected false positives. At the same time, it minimizes the missing tag detection and identification time by first estimating the number of unexpected tags in the population and then using it along with the false-positive probability to obtain optimal frame sizes and minimum number of times Aloha frames should be executed to mitigate the effects of false positives. RUN works with multiple readers with overlapping regions. It is easy to deploy, because it is implemented on readers as a software module and does not require any modifications to tags or to the communication protocol between the tags and the readers. We implemented RUN along with four major missing tag detection and identification protocols, namely, TRP, IIP, MTI, and SFMTI, and the fastest tag ID collection protocol TH and compared them side by side. Our performance evaluation results show that RUN is the only protocol that achieves required reliability in the presence of unexpected tags, whereas the best existing protocol achieves a maximum reliability of only 67%. RUN identifies 100% of missing tags in the presence of unexpected tags, whereas the best existing protocol identifies a maximum of only 60% of missing tags.

Tag Memory-Erasure Tradeoff of RFID Grouping Codes

We analyze the memory-erasure tradeoff of recently proposed radio frequency identification (RFID) grouping codes. Grouping codes make it possible for an RFID reader to automatically verify the integrity of a collection of RFID tagged objects and identify any missing objects without having access to external sources. They add redundancy to the memory of tags that is then used to recover missing tag identification data (forward error correction). We present a lower bound for the redundancy and show that it can be realized asymptotically. We then consider optimized approximations for practical settings and show that their memory-erasure tradeoff is close to optimal and significantly less than that of recently proposed grouping codes.

P-MTI: Physical-Layer Missing Tag Identification via Compressive Sensing

Radio frequency identification (RFID) systems are emerging platforms that support a variety of pervasive applications. RFID tags can be used to label items and enable item-level monitoring. The problem of identifying missing tags in RFID systems has attracted wide attention due to its practical importance (e.g., anti-theft). This paper presents P-MTI: a Physical-layer Missing Tag Identification scheme that effectively makes use of the lower-layer information and dramatically improves operational efficiency. Unlike conventional approaches, P-MTI looks into the aggregated tag responses instead of focusing on individual tag responses and extracts useful information from physical-layer collisions. P-MTI leverages the sparsity of missing tag events and reconstructs tag responses through compressive sensing. We prototype P-MTI using the USRP software defined radio and Intel WISP platform. We also evaluate the performance of P-MTI with extensive simulations and compare to previous approaches. The experiment results show the promising performance of P-MTI in identification accuracy, time efficiency, as well as robustness over noisy channels.