• Proceedings of the Korean Information Science Society Conference
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• 2006.06d
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• pp.91-93
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• 2006

RFID(Radio Frequency IDentification) 기술은 RF 신호를 사용하여 물품에 부착된 전자 태그(tag)를 식별하는 비접촉자동인식 기술이다. 이런 RFID 기술의 확산을 위해서는 리더가 다수의 태그를 빠른 시간 안에 인식하는 다중 태그 식별 문제를 해결 해야만 한다. 지금까지 이 문제를 해결하기 위한 충돌 방지(anti-collision) 알고리즘이 많이 개발되었다. 본 논문에서는 이런 충돌 방지 알고리즘 중에서 18000-6 Type A, Type B와 Type C로 새롭게 채택된 EPCglobal Class1 Generation2, 그리고 Query Tree Protocol에 대한 시뮬레이션 시스템의 구조를 소개하고 실제 시뮬레이션 했을 때의 각 알고리즘에 대한 간단한 성능 평가를 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1B
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• pp.85-94
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• 2010

Many RFID systems use dynamic slotted ALOHA to identify the label information of the RFID tags. One of the key problems in the RFID system is how to estimate the number of RFID tags up to the desired level of accuracy. In this paper, we present the framework of tag estimation algorithm for the collision-oblivious (CO) reader which can only decide whether the tag response is successful or not. Thus, the CO reader must rely on the success estimator to predict the RFID tag population. We propose two estimation algorithms to predict the number of RFID tags, named the memoryless success estimator (MSE) and the intersection-based success estimator (ISE). The MSE considers only the estimate obtained at the current inventory round, while the ISE finds an appropriate intersection interval of the existing estimates collected at every inventory round. Through the simulation results, we demonstrate that the ISE is a fast, accurate, and controllable estimator whose performance is close to that of the collision/idle estimators.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.1005-1014
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• 2010

When reader collect tags, we found that they tend to get together to specific interface in Multi-Interface Multi-Channel 2.4GHz Active RFID system. To solve this problem, we designed the LP-Combind and AP-Balanced protocol for load distribution between interfaces, then verified its superiority of the performance through the simulation. There are three problems to implement designed protocols in hardware of firmware-level. first, tag selects randomly the channel of reader and reader need the method which can change the channel of tags. second, reader has the synchronization problem between reader and tag. third, reader has problem that MCU of reader have to operate simultaneously dual interface. To slove this problems, we designed the message and implemented method for tag channel change and the protocol in order to adjust synchronization between reader and tag, Therefore, we compared and analyzed the performance of protocols by experiment. If LP windows size is same, the performance of LP-Combined protocol and AP-Balanced protocol which lower collision probability by its load distribution is more outstanding than single interface protocol performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.6
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• pp.999-1005
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• 2008

RFID(Radio Frequency IDintification) leader is collision of data, when recognizing the multiple tag the inside area. This collision became the cause which delays the tag recognition time of the leader. The protocol which prevents the delay of tag recognition time of the leader the place where representative it uses QT(Query Tree) algorithms, it uses a collision bit position from this paper and are improved QT-MTC(Query Tree with Multi-Tag Cognition) algorithms which it proposes. This algorithm stored the bit position which bit possibility and the collision where the collision happens occurs in the stack and goes round a tree the number of time which, it reduced could be identified two tags simultaneously in order, it was planned. A result of performance analysis, It compared in QT protocols and the this algorithm against the tag bit which is continued a high efficiency improvement effect was visible.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.565-568
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• 2005

RFID system allows contactless identification of objects, where small tags are attached to objects and information of objects are transferred using radio frequency. In recent years, industries have incorporated several identification systems to its production processes, which allow collecting automatically information about goods. In order to communicate with a single tag out of a group of tags, the target tag has to be identified. Therefore the read has to attempt to obtain the unique identification code of each tag within its read range. This paper presents performance results of QT and QT-sl protocols, which are tag identification protocols incorporating memoryless property. The memoryless property is that the current response of each tag only depends on the current query of the reader but not on the past history of the reader's queries.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.1
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• pp.6-12
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• 2004

Identification rate and time are very important in the identification of RFID tag, and the tag requires simple structure to use economically large quantity of tags. These factors make the MAC protocols of wired or wireless network environment result in different requirements. In the paper, we propose a method to apply spread spectrum scheme using orthogonal channel via Walsh function as the anti-collision communication system for the purpose of non-collision identification of multiple tags, and consider its property. The proposed system use two step identification. in the first step, collision is resolved via constructing to respond after specific delay time based on unique n, and conventional polling scheme follows in the second step.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.1
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• pp.19-25
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• 2012

In evaluating the performance of RFID systems, the tag anti-collision arbitration has been considered to be an important issue. For BT(Binary Tree) and ABS( Adaptive Binary Splitting) protocols, the so-called capture effect, which presumably happens frequently in the process of readers' receiving messages from multiple tags, can lead to some failures in detecting all tags in BT and ABS. In this paper, we propose a new anti-collision protocol, namely FTB (Feedback TagID with Binary splitting), which can solve the aforementioned problem and improve the performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.6
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• pp.435-445
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• 2013

One of the most challenging issues in radio frequency identification (RFID) and near field communications (NFC) is to correctly and quickly recognize a number of tag IDs in the reader's field. Unlike the probabilistic anti-collision schemes, a query tree based protocol guarantees to identify all the tags, where the distribution of tag IDs is assumed to be uniform. However, in real implements, the prefix of tag ID is uniquely assigned by the EPCglobal and the remaining part is sequentially given by a company or manufacturer. In this paper, we propose an enhanced M-ary query tree protocol (EMQT), which effectively reduces unnecessary query-response cycles between similar tag IDs using m-bit arbitration and tag expectation. The theoretical analysis and simulation results show that the EMQT significantly outperforms other schemes in terms of identification time, identification efficiency and communications overhead.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.3
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• pp.413-420
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• 2006

In this thesis, a RFID baseband system is implemented based on the international standard ISO/IEC 18000-6 Type-B using FPCA, and also anti-collision algorithm is implemented to improve the system performance. We compares the performance of the proposed anti-collision algorithm with that binary tree algorithm and bit-by-bit algorithm, and also validated analytic results using OPNET simulation. The proposed algorithm for Type-B transmission protocol and collision prohibition was designed using ISE7.1i which is a FPGA design-tool of Xilinx and implemented with Spartan2 chip which is a FPGA device.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.5
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• pp.931-936
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• 2016

The PS algorithm divides the number of tags within the identification range of reader into smaller groups by increasing the transmission power incrementally and identifies them. It limits the number of responding tags by grouping the tags within the identification range of the reader, and thus can reduce the probability of tag collision. Also, in the PS algorithm, the reader takes advantages of the difference of identification ranges. This algorithm uses the fixed frame size at every scan. Therefore, it has problems that the performance can be shown variously according to the number of tags and frame size. In this paper, we propose an EPS algorithm that allocates the optimal frame size by estimating the number of tags at each scan, and apply it into the STAC protocol. The simulation results showed that STAC/EPS algorithm can improve the identification delay about 45% compared with STAC protocol. Also, it provides a stable identification delay regardless of power level increase.