• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권11호
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• pp.1929-1945
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• 2011

RFID technologies have attracted a lot of attention in recent years because of their cost/time-effectiveness in large-scale logistics, supply chain management (SCM) and other various potential applications. One of the most important issues of the RFID-based systems is how quickly tags can be identified. Tag collision arbitration plays a more critical role in determining the system performance especially for passive tag-based ones where tag collisions are dealt with rather than prevented. We present a novel tag collision arbitration protocol called Optimum Frame-Slotted Aloha (OFSA). The protocol has been designed to achieve time-optimal efficiency in tag identification through an analytic study of tag identification delay and tag number estimation. Results from our analysis and extensive simulations demonstrate that OFSA outperforms other collision arbitration protocols. Also, unlike most prior anti-collision protocols, it does not require any modification to the current standards and architectures facilitating the rollout of RFID systems.

• ETRI Journal
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• 제30권5호
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• pp.653-662
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• 2008

Arbitration of tag collision is a significant issue for fast tag identification in RFID systems. A good tag anti-collision algorithm can reduce collisions and increase the efficiency of tag identification. EPCglobal Generation-2 (Gen2) for passive RFID systems uses probabilistic slotted ALOHA with a Q algorithm, which is a kind of dynamic framed slotted ALOHA (DFSA), as the tag anti-collision algorithm. In this paper, we analyze the performance of the Q algorithm used in Gen2, and analyze the methods for estimating the number of slots and tags for DFSA. To increase the efficiency of tag identification, we propose new tag anti-collision algorithms, namely, Chebyshev's inequality, fixed adjustable framed Q, adaptive adjustable framed Q, and hybrid Q. The simulation results show that all the proposed algorithms outperform the conventional Q algorithm used in Gen2. Of all the proposed algorithms, AAFQ provides the best performance in terms of identification time and collision ratio and maximizes throughput and system efficiency. However, there is a tradeoff of complexity and performance between the CHI and AAFQ algorithms.

• 한국IT서비스학회지
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• 제12권3호
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• pp.331-343
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• 2013

In RFID systems, the anti-collision algorithm is being improved to recognize Tag's ID within recognition area of the reader quickly and efficiently. This paper focuses on Tag collision. Many studies have been carried out to resolve Tag collision. This paper proposes a new N-ary Query Tree Algorithm to resolve more than Tag collision simultaneously, according to the value of m(2 ~ 6). This algorithm can identify more tags than existing methods by treating a maximum 6 bit collision, regardless of the continuation/non-continuation Tag's ID patterns. So, it extracts maximumly different $2^6$ bit patterns per single prefix in recognition process. The performance of N-ary Query Tree Algorithm is evaluated by theoretical analysis and simulation program.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2007년도 하계종합학술대회 논문집
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• pp.29-30
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• 2007

In this paper, we propose Group Separation(GS) algorithm for RFID tag recognition. In GS algorithm, reader calculates tag ID by collision point, stores memory with the collision table. And reader classifies according to total number of tag ID's 1, requests each group. If tag comes into collision with the other tag, reader searches tag ID in collision table. As a result, we observes that transmitted data rate, the recognition time is decreased.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 춘계종합학술대회 A
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• pp.253-259
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• 2008

RFID is a generic term for technologies which use RF waves to identify, track, or categorize any object. A radio frequency identification (RFID) reader recognizes objects through wireless communications with RFID tags. Tag collision arbitration for passive tags is a significant issue for fast tag identification due to communication over a shared wireless channel. One of the research areas in RFID system is a tag anti-collision protocol. In this paper, various anti-collision protocols are discussed. The pros and cons of different anti-collision protocols are compared with each other and their performance is analyzed and the better performance anti-collision protocol is suggested.

• 한국철도학회논문집
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• 제4권4호
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• pp.155-161
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• 2001

In this paper, the method is suggested to prevent data collision or damage on RFID(Radio Frequency Identification) system, in case a reader reading multi-tag simultaneously, using binary-search algorithm and Time-domain anti-collision procedure at reader and tag, respectively. The RFID system is designed that Reader enable to communicate with Tag on 13.56MHz bandwidth which is ISM(Industrial Science Medical) bandwidth, antennas of Tag part are designed using MCRF335 Chip. When RF communication is achieved between reader and tag, in case that data is transmitted to reader pass through multiple tags simultaneously, a study on the anti-collision method for the situation that the data collision occurs is performed.

• 한국통신학회논문지
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• 제33권8A호
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• pp.805-814
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• 2008

Both EPCglobal Generation-2 (Gen2) for passive RFID systems and Intelleflex for semi-passive RFID systems use probabilistic slotted ALOHA with Q algorithm, which is a kind of dynamic framed slotted ALOHA (DFSA), as the tag anti-collision algorithm. A better tag anti-collision algorithm can reduce collisions so as to increase the efficiency of tag identification. In this paper, we introduce and analyze the estimation methods of the number of slots and tags for DFSA. To increase the efficiency of tag identification, we propose two new tag anti-collision algorithms, which are Chebyshev's inequality (CHI) algorithm and hybrid Q algorithm, and compare them with the conventional Q algorithm and adaptive adjustable framed Q (AAFQ) algorithm, which is mentioned in Part I. The simulation results show that AAFQ performs the best in Gen2 scenario. However, in Intelleflex scenario the proposed hybrid Q algorithm is the best. That is, hybrid Q provides the minimum identification time, shows the more consistent collision ratio, and maximizes throughput and system efficiency in Intelleflex scenario.

• 한국산업정보학회논문지
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• 제15권3호
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• pp.1-9
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• 2010

최근 유비쿼터스 환경 구축의 가장 핵심은 센서 네트워크와 RFID 시스템이다. 이 중 RFID 시스템은 태그의 전자정보를 RF 신호를 이용하여 리더에게 전송한다. RFID 시스템은 다중 태그의 존재로 인해 충돌이 발생하고 태그 인식 성능이 저하된다. 그래서 태그 충돌을 중재할 수 있는 방법이 필요하다. 본 논문은 태그 간 충돌을 줄이며 좀 더 빠른 태그 인식이 가능한 하이브리드 방법을 제안한다. 본 논문에서 제안하는 방법은 트리기반 알고리즘의 장점인 확실성을 기반으로 동작하며 충돌을 줄이기 위해 태그 아이디를 이용하여 전송 타임 슬롯을 결정한다. 시뮬레이션을 통한 성능평가에서 다른 트리기반의 알고리즘과 다른 하이브리드 알고리즘에 비하여 충돌 횟수와 쿼리 수에서 높은 성능을 가진다는 것을 보여준다.

• 전기전자학회논문지
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• 제25권1호
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• pp.32-36
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• 2021

This paper presents a novel collided tag signals's periodic characteristic based radio frequency identification (RFID) tag collision detection method for the ultra high frequency (UHF) RFID. The proposed method utilizes that periodicity of tag signals is maintained even under tag collision. In the proposed method, the correlation between received signal and reference edge signal is used. Simulation result shows that the detection performance using the proposed method is about 10 dB better than that of existing method. In addition, the detection performances with different magnitude difference, phase difference, delay, number of tags are analyzed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권4호
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• pp.1460-1478
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• 2020

This paper proposes a novel anti-collision protocol for large-scale RFID tags identification, named Bi-response Collision Tree Protocol (BCT). In BCT, two group of tags answer the reader's same query in two response-cycles respectively and independently according to the bi-response pattern. BCT improves the RFID tag identification performance significantly by decreasing the query cycles and the bits transmitted by the reader and tags during the identification. Computation and simulation results indicate that BCT improves the RFID tag identification performance effectively, e.g. the tag identification speed is improved more than 13.0%, 16.9%, and 22.9% compared to that of Collision Tree Protocol (CT), M-ary Collision Tree Protocol (MCT), and Dual Prefix Probe Scheme (DPPS) respectively when tags IDs are distributed uniformly.