Tag Collision Research Articles

An Adaptive Anti-Collision Protocol for Large-Scale RFID Tag Identification

Tag collision presents a significant impact on RFID systems. In this letter, we propose an efficient tag anti-collision protocol termed the adaptive assigned tree slotted Aloha anti-collision (AdATSA) protocol. In this protocol, the binary grouping and adaptive recognition phases are employed to effectively estimate the tag number and promptly identify tags. Additionally, we further improve the system efficiency of AdATSA by investigating the influence factor between the frame length and the tag number. Through numerical results, we are able to obtain several values of the influence factor, which helps to achieve the optimal system efficiency for AdATSA. Both analytical and simulation results are presented to show that the highest system efficiency of AdATSA is 61.7%, outperforming the previous protocols.

Tag Modulation Silencing: Design and Application in RFID Anti-Collision Protocols

Reliable and energy-efficient reading of Radio Frequency IDentification (RFID) tags is of utmost importance, especially in mobile and dense tag settings. We identify tag collisions as a main source of inefficiency in terms of wasting both medium access control (MAC) frame slots and reader's energy. We propose modulation silencing (MS), a reader-tag interaction framework to limit the effect of tag collisions. Utilizing relatively simple circuitry at the tag, MS enhances the performance of existing anti-collision protocols by allowing readers to terminate collision slots once a decoding violation is detected. With shorter collision slots, we revisit the performance metrics and introduce a new generalized time efficiency metric and an optimal frame selection formula that takes into consideration the MS effects. Through analytical solutions and extensive simulations, we show that the use of MS results in significant performance gains under various scenarios.

Efficient Particle Filter Localization Algorithm in Dense Passive RFID Tag Environment

The means of distributing dense passive radio-frequency identification (RFID) tags has been widely utilized for accurate indoor localization. However, they suffer a disadvantage on low localization precision due to the increasing interference of RFID tag collisions and the variation of behavior of tags. Current localization algorithms used in passive RFID location systems are mostly deterministic and have a limited capability on improving localization precision in a dynamic environment with uncertain sensor measurement. This paper investigates the feasibility of using particle filter technique as an efficient localization approach to deliver both relatively good accuracy and precision in dense passive RFID tag distribution applications. A position feature-based system model is first built to apply the typical particle filter technique in passive RFID location applications. Then, a new particle filter algorithm by using a moving direction estimation-based feature improvement scheme is proposed to enhance localization precision in a dense passive RFID tag environment. Experimental results show that the proposed method can provide relatively good accuracy and precision for passive RFID location applications, with an improved performance over the typical particle filter algorithm and a state-of-the-art deterministic method.

Research of RFID Tag Anti-collision Algorithm based on Binary Tree

To solve the RFID tag collision problem, a new anti-collision algorithm is proposed by improving the binary tree search algorithm. Through improving the requesting establishment, this algorithm reduces the probability of collision bits and the number of tags requiring collision detection time by using the even number bits for impact identification. The simulation results show that compared with the traditional binary tree search algorithm and dynamic binary tree search algorithm, this algorithm has obvious advantages in terms of the length of the transmission of binary data. In addition, in terms of the average number of requests, the proposed algorithm provides the same performance with the faster identification process, and reduces the time of the transmission of information

Study on the Improved Recession Binary Tree Algorithm

Tag collision problems seriously affected the performance of the RFID system. In order to solve this problem, we proposed an improved Recession Binary Tree Algorithm to avoid duplication and redundancy search, so that system throughput can substantial increased in the case of there have large quantities of labels.

An Improved RFID Tag Collision Algorithm

Tag collision is a very important research direction in the RFID system. Probabilistic solving algorithm is one of the important way to solve the tag collision, dynamic frame slot ALOHA (DFSA) algorithm is more commonly used at present and the probabilistic algorithm with better effect. This paper proposes an Advanced DFSA (ADFSA) which is based on a dynamic frame slot ALOHA algorithm, combined with multiplier factor and grouping thoughts. the algorithm is simple, at the same time, the simulation results show that IDFSA algorithm has better performance.

Group improved enhanced dynamic frame slotted ALOHA anti-collision algorithm

With the development of information technology and declining in the cost of tags, radio frequency identification (RFID) system has become more and more popular, which has been widely used in a lot of areas, such as logistics tracking, animals identification, medicine, electronic toll collection, inventory, asset management, manufacturing, etc. However, when we use RFID technology to identify the objects, tag collision is one of the important factors to influence the identification efficiency. Currently, Aloha-based algorithm is one of the popular anti-collision algorithms which performs well when the number of tags is small. But it is not very efficient for cases with large number of tags and some areas which tags' number can be estimated, such as warehouse, supermarket, the production lines of smart factory and so on. So in this paper, we proposed a new anti-collision algorithm called group improved enhanced dynamic frame slotted ALOHA (GroupIEDFSA) by estimating the number of unread tags first, comparing the maximum frame size and dividing tags into groups when the number of tags which are activated is large. What is more, compared with enhanced dynamic frame slotted ALOHA (EDFSA) algorithm in the process of identification, GroupIEDFSA algorithm will combine new group based on the unread tags' number. Simulation results show that the efficiency of GroupIEDFSA algorithm system improves by 20 % in time and over 50 % in rounds than EDFSA algorithm in the standard mode, and increases by 1 % in time when we used fast mode.

Numeric Evaluation on the System Efficiency of the EPC Gen-2 UHF RFID Tag Collision Resolution Protocol in Error Prone Air Interface

Efficient resolution of the tag collisions is the key for the RFID systems to be universally adopted. To resolve the tag collision occurred in the UHF RFID system, the EPC Gen-2 protocol, proposed by the EPCglobal Inc., was adopted as an international standard and have been widely accepted in industry. However, little research works has been taken to evaluate the performance of this protocol in nonperfect and error prone air interface. In this paper, to evaluate the performance of the EPC Gen-2 protocol, a system efficiency model is proposed, and, based on the model, numeric simulations are performed to evaluate the EPC Gen-2 protocol in error prone air interface. Simulation results reveal that the system efficiency of the EPC Gen-2 protocol is seriously affected by the capture and noise effects.

Method of ID – BTS Tag Recognition Based on the QT Protocol

With the rapid development of Internet of things, the RFID technology also develops very fast. Because of the RFID system has the advantage of low cost and do not require to contact identification, it has been used in many applications. But when system works, there may be many tags at the same time around the reader and may cause the collision problem. In this paper, we propose a Method of ID - BTS tag recognition based on the QT protocol. This method can effectively solve the problem of tag collision and it has fewer times of tags searching and less traffic.

Managing the Number of Tag Bits Transmitted in a Bit-Tracking RFID Collision Resolution Protocol

Radio Frequency Identification (RFID) technology faces the problem of message collisions. The coexistence of tags sharing the communication channel degrades bandwidth, and increases the number of bits transmitted. The window methodology, which controls the number of bits transmitted by the tags, is applied to the collision tree (CT) protocol to solve the tag collision problem. The combination of this methodology with the bit-tracking technology, used in CT, improves the performance of the window and produces a new protocol which decreases the number of bits transmitted. The aim of this paper is to show how the CT bit-tracking protocol is influenced by the proposed window, and how the performance of the novel protocol improves under different conditions of the scenario. Therefore, we have performed a fair comparison of the CT protocol, which uses bit-tracking to identify the first collided bit, and the new proposed protocol with the window methodology. Simulations results show that the proposed window positively decreases the total number of bits that are transmitted by the tags, and outperforms the CT protocol latency in slow tag data rate scenarios.

RFID Technology and Applications

RFID is emerging as one of most fundamental technologies to Internet of Things due to its attractive features such as good reading ranges, high data rates, and low cost. RFID has achieved a widespread success in various applications, ranging from asset tracking, highway toll collection, supply chain management, animal identification to surveillance systems. Moreover, there has been a wide scope of development in RFID standards, protocols, and middleware. However, a series of challenging issues should be properly addressed before a massive adaptation of RFID technology. In this special issue, we have received 24 paper submissions and accepted 9 papers finally according to the reviewers’ comment and associate editors’ suggestion. These accepted papers include RFID reader antenna design, RFID tag antenna design, RFID passive transponders, tag collision algorithm, and RFID application systems. B. Lee et al. from Kwangwoon University of Korea proposed a novel structure of an NFC loop antenna for mobile handset applications by improving the performance of an NFC loop antenna when a ferrite-polymer composite is attached between the embedded NFC loop antenna and the phone battery. The proposed loop antenna gives better performance than that of a conventional NFC loop antenna. L. X. Zheng et al. from South China University of Technology proposed a compact RFID reader antenna for UHF near-field and far-field operations. The structure of the antenna is a novel folded-dipole loop and is formed by a concentric metal ring with a split. It can provide uniform magnetic near-field distribution and available farfield gain. Y. Yao et al. from Beijing University of Posts and Telecommunications also proposed a novel RFID reader antenna. This antenna was fabricated using indium tin oxide film; thus, it has optically transparent characteristic.This kind of antenna can be used in clothing stores. P. Jankowski-Mihulowicz et al. from Rzeszow University of Technology proposed novel RFID passive transponders with additional energy harvester. They can recover energy from the electromagnetic field of read device and the harvested energy was utilized to supply a microprocessor acquisition block for developed LTCC pressure sensor. C. Wang et al. from Beijing University of Posts and Telecommunications proposed an advanced dynamic framed-slotted ALOHA algorithm based on Bayesian estimation and probability response to solve the tag collision problem of RFID system. The simulation results show that the proposed algorithm has better performance. We sincerely hope that this special issue can further help the readers to understand RFID antenna design and applications and explore the future development of the system.

Four-ary query tree splitting with parallel responses for RFID tag anti-collision

In a radio frequency identification (RFID) system, tags can be identified by a reader when they are within the interrogation zone of the reader. Collisions occur when tags using backscatter technology report their IDs to the reader at the same carrier frequency simultaneously. The performance of tag identification is degraded by collisions, so it is important to address the tag collision problem. Several anti–collision protocols have been proposed for reducing tag collisions. They can be categorised into two classes: ALOHA–based and tree–based protocols. This paper proposes a 4–ary query tree–based anti–collision protocol, namely the parallel response query tree (PRQT) protocol, to improve the performance of tag identification. In the PRQT protocol, the tags with the ID prefix matching either the reader's request bit string or the complementary of the string are arranged to respond in two subcarriers in parallel. The PRQT protocol is analysed, simulated and compared with related ones to demonstrate its advantages.

Time-Efficiency-Oriented Missing-Tag Identification Protocols for Large-Scale RFID Systems

One fundamental and significant issue for large-scale radio frequency identification (RFID) systems is to promptly identify the missing events of passive tags. To this end, this letter proposes two novel protocols, Tag Retardation-based Compact Protocol (TRCP) and Probabilistic Prediction-based Protocol (P <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> ), which address the missing-tag identification problem in a more time-efficient way than existing work. TRCP conducts tag retardation to alleviate tag collisions and achieve compact tag transmissions. Due to the fact that it is unnecessary to individually identify the tags that are likely to be missing simultaneously, we design P <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , which leverages tag missing probability to avert needless tag retardation to further ameliorate TRCP. Simulation results validate the superiority of both TRCP and P <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> to state-of-the-art studies in terms of time efficiency.

RFID 시스템 인식속도 개선을 위한 충돌방지 알고리즘

RFID 시스템에서 해결하여야 할 가장 큰 문제 중 하나는 태그간의 충돌로 인해 인식 효율이 떨어진다는 것이다. 기존의 충돌 방식 중 BS 충돌 방지 알고리즘 방식은 구현이 간단하다는 장점이 있으나, 태그 수가 많아짐에 따라서 태그간 충돌에 의해 전체 태그를 읽는데 요구되는 단계별 스케줄 횟수가 증가하는 단점을 가지고 있다. 본 논문에서는 이 문제를 해결하기 위해서 충돌 예상을 최소화하기 위해 사전에 '0'과 '1'의 결정 비트를 통한 복수 응답 프레임 방식을 제안하였다. In RFID System, one of the problem that we must slove is to devise a good anti-collision algorithms to improve the efficiency of tag identification which is usually low because of tag collision. Among of the existing RFID anti-collision algorithm, BS (Binary Search) algorithm, though simple, has a disadvantage that the stage 0f times used to identify the tags increase exponentially as the number of tags does. In this Paper, I propose a new anti-collision algorithm called Multi-collision reflected frame which restricts the number of stages and decided bit. Since the proposal algorithm keep the length size of UID and density of total tag when have 100%.

A Novel RFID Anti-Collision Algorithm based on Binary Tree

The method to deal with the tag collision in RFID system can be directly called “Multiple Access”. According to the ideas of these different anti-collision algorithms, they can be divided into two categories. One is the binary tree algorithm based on deterministic; the other is the statistical-based ALOHA algorithm. Overall, however, there is still room for improvement on anti-collision algorithm path optimization and communication complexity,. This paper focuses on binary tree algorithm. After analysis of the basic binary tree algorithm, dynamic binary tree algorithm, Trajan binary tree algorithm, paper propose a novel binary tree algorithm based on the dichotomy. Simulation performance shows that there have upgraded path optimization and communication efficiency

Efficient Object Localization Using Sparsely Distributed Passive RFID Tags

Radio-frequency identification (RFID) technology has been widely used in passive RFID localization application due to its flexible deployment and low cost. However, current passive RFID localization systems cannot achieve both highly accurate and precise moving object localization task owing to tag collisions and variation of the behavior of tags. Most researchers increase the density of tag distribution to improve localization accuracy and then consider using either anti-collision process embedded in the hardware of the RFID reader or advanced localization algorithms to enhance localization precision. However, advanced anti-collision processes for RFID devices are challenged by the physical constraint characteristics of radio frequency; and improved localization algorithm cannot fundamentally reduce the impacts of tag collision on localization precision. This research work attempts to improve localization precision of a passive RFID localization system by using sparsely distributed RFID tags. This paper first defines a measure for accuracy and precision in a passive RFID localization system with regard to RFID tag distribution. An exponential-based function is then derived from experimental measurements, which reflects the relationship between RFID tag distribution and localization precision. This function shows that localization precision is mainly determined by tag density of RFID tag distribution. Based on the experimental findings, a sparse RFID tag distribution approach is proposed. The results show that in comparison with the conventional RFID tag distribution, passive RFID localization system with sparse RFID tag distribution can deliver a higher localization precision for the required accuracy.

An Efficient Adaptive Anticollision Algorithm Based on 4-Ary Pruning Query Tree

In radio frequency identification system (RFID), the efficiency in which the reader identifies multiple tags is closely related to the methods to solve the collision of multiple tags. At present, a reasonable solution is the introduction of 4-ary query tree (or n-ary query tree) to reduce the collision time slots and additional query is used to decrease idle timeslots. The advantage of a 4-ary tree anti-collision algorithm is that it is able to reduce collision timeslots, but it also increases the idle timeslots. To reduce these excessive idle timeslots the 4-ary tree anticollision algorithm brings, an anti-collision algorithm based on adaptive 4-ary pruning query tree (A4PQT) is proposed in this paper. On the basis of the information of collision bits, some idle timeslots can be eliminated through pruning the 4-ary tree. Both theoretical analysis and simulation results support that A4PQT algorithm can significantly reduce recognition time and improve throughput of the RFID system.

RFID 시스템에서 효율적인 분리를 이용한 충돌 방지 알고리즘

RFID 시스템에서, 리더의 인식영역에서 다수의 태그를 인식하는 과정에서 충돌이 발생하게 된다. 하나의 리더에게 두 개 또는 여러 태그가 응답하여 충돌이 발생하게 되며, 리더는 태그를 인식하지 못하는 일이 발생한다. 이런 충돌로 인해 리더는 인식영역 안에 있는 모든 태그를 인식하기 위한 시간이 길어지며, 이 경우 리더는 태그를 인식하지 못하는 경우가 발생된다. 리더는 인식영역 안의 모든 태그를 빠르게 인식할 수 있는 충돌 방지 알고리즘이 필요하다. 제안된 알고리즘은 태그의 응답을 효율적인 분리를 이용하여 태그 그룹으로 나누어 충돌을 회피한다. 또한, 제안된 알고리즘은 태그 아이디의 모든 비트를 알지 못해도 태그를 인식할 수 있다. 효율적인 분리를 통해 예측을 하여 리더로 부터의 응답 수를 줄인다. In the RFID system, multiple tags respond in the process of identifying multiple tags in the reader's interrogation zone, resulting in collisions. Tag collision occurs when two or more tags respond to one reader, so that the reader cannot identify any tags. These collisions make it hard for the reader to identify all tags within the interrogation zone and delays the identifying time. In some cases, the reader cannot identify any tags. The reader needs the anti-collision algorithm which can quickly identify all the tags in the interrogation zone. The proposed algorithm efficiently divides tag groups through an efficient separation to respond, preventing collisions. Moreover, the proposed algorithm identifies tags without checking all the bits in the tags. The prediction with efficient separation reduces the number of the requests from the reader.

An Efficient Anti-collision Protocol for Fast Identification of RFID Tags

Tag collision prevention/resolution for radio frequency identification (RFID) tags is one of the most significant issues for fast tag identification. This paper proposes a new anti-collision protocol that has objective of minimizing the tag identification delay. The proposed scheme reduces the tag collisions by allocating exclusive timeslot to each tag using identified timeslot information. Performance evaluation based on numerical and simulation results shows that the proposed anti-collision method improves RFID identification performance.

Assigned Tree Slotted Aloha RFID Tag Anti-Collision Protocols

With the development of radio frequency identification (RFID) technology, RFID systems have been used in various applications. But the tag collision problem greatly affects the performance of many RFID systems, especially in large scale tag identification environments. In this paper, we propose two new efficient tag anti-collision protocols, i.e., the assigned tree slotted Aloha (ATSA) protocol and the improved ATSA (ImATSA) protocol based upon Manchester encoding. The key technology is to apply the prefix matching idea to the dynamic frame slotted Aloha identification model by assigning a unique ID prefix to each frame and slot. Both theoretical and simulation results indicate that ImATSA can achieve an average system efficiency of around 58%.