• Title/Summary/Keyword: 태그 충돌 프로토콜

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Multichannel Anticollision Protocol for Improving Tag Collection Performance in Active RFID Systems (능동형 RFID 시스템에서 태그 수집 성능 향상을 위한 다중채널 기반 충돌방지 프로토콜)

  • Yoon, Won-Ju;Chung, Sang-Hwa;Park, Shin-Jun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.1A
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    • pp.50-57
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    • 2009
  • Tag collection is one of the major functions in RFID systems. In this paper, we propose a multichannel slotted-aloha anticollision protocol to mitigate the tag collision problem and improve tag collection performance in active RFID systems. In the proposed anticollision protocol, while an RFID reader transmits commands to multiple RFID tags via a common channel, it receives multiple tag responses over multiple channels simultaneously. We also implemented an active RFID system supporting the proposed anticollision protocol. In experiments with the implemented reader and 60 tags, the proposed dual-channel slotted-aloha anticollision protocol showed a large improvement in tag collection performance compared with the single-channel slotted-aloha anticollision protocol. With 60 tags, the average time spent on tag collection using the dual-channel anticollision protocol was 600.543 ms, which was 46.3% of the 1289.721 ms required using the single-channel anticollision protocol.

Adaptive RFID anti-collision scheme using collision information and m-bit identification (충돌 정보와 m-bit인식을 이용한 적응형 RFID 충돌 방지 기법)

  • Lee, Je-Yul;Shin, Jongmin;Yang, Dongmin
    • Journal of Internet Computing and Services
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    • v.14 no.5
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    • pp.1-10
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    • 2013
  • RFID(Radio Frequency Identification) system is non-contact identification technology. A basic RFID system consists of a reader, and a set of tags. RFID tags can be divided into active and passive tags. Active tags with power source allows their own operation execution and passive tags are small and low-cost. So passive tags are more suitable for distribution industry than active tags. A reader processes the information receiving from tags. RFID system achieves a fast identification of multiple tags using radio frequency. RFID systems has been applied into a variety of fields such as distribution, logistics, transportation, inventory management, access control, finance and etc. To encourage the introduction of RFID systems, several problems (price, size, power consumption, security) should be resolved. In this paper, we proposed an algorithm to significantly alleviate the collision problem caused by simultaneous responses of multiple tags. In the RFID systems, in anti-collision schemes, there are three methods: probabilistic, deterministic, and hybrid. In this paper, we introduce ALOHA-based protocol as a probabilistic method, and Tree-based protocol as a deterministic one. In Aloha-based protocols, time is divided into multiple slots. Tags randomly select their own IDs and transmit it. But Aloha-based protocol cannot guarantee that all tags are identified because they are probabilistic methods. In contrast, Tree-based protocols guarantee that a reader identifies all tags within the transmission range of the reader. In Tree-based protocols, a reader sends a query, and tags respond it with their own IDs. When a reader sends a query and two or more tags respond, a collision occurs. Then the reader makes and sends a new query. Frequent collisions make the identification performance degrade. Therefore, to identify tags quickly, it is necessary to reduce collisions efficiently. Each RFID tag has an ID of 96bit EPC(Electronic Product Code). The tags in a company or manufacturer have similar tag IDs with the same prefix. Unnecessary collisions occur while identifying multiple tags using Query Tree protocol. It results in growth of query-responses and idle time, which the identification time significantly increases. To solve this problem, Collision Tree protocol and M-ary Query Tree protocol have been proposed. However, in Collision Tree protocol and Query Tree protocol, only one bit is identified during one query-response. And, when similar tag IDs exist, M-ary Query Tree Protocol generates unnecessary query-responses. In this paper, we propose Adaptive M-ary Query Tree protocol that improves the identification performance using m-bit recognition, collision information of tag IDs, and prediction technique. We compare our proposed scheme with other Tree-based protocols under the same conditions. We show that our proposed scheme outperforms others in terms of identification time and identification efficiency.

Performance Improvement of STAC Protocol by Grouping the Number of Tags (태그 수 그룹화를 통한 STAC 프로토콜의 성능 개선)

  • Lim, Intaek
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.4
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    • pp.807-812
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    • 2015
  • In RFID system, when multiple tags respond simultaneously, a collision can occur. A method that solves this collision is referred as anti-collision algorithm. In 13.56MHz RFID system of Auto-ID center, STAC protocol is defined as an anti-collision algorithm for multiple tag reading. The PS algorithm divides the tags within the identification range of reader into smaller groups by increasing the transmission power incrementally and identifies them. In this paper, we propose a STAC/PS algorithm that the PS algorithm is applied in the STAC protocol. Through simulations, it is demonstrated that the collision rate for the proposed algorithm is about 50% lower than STAC protocol. Therefore, the STAC/PS algorithm can achieve faster tag identification speed compared with STAC protocol due to the low collision rate.

A Hybrid Anti-Collision Protocol using Bit Change Sensing Unit in RFID System (RFID 시스템에서 비트변화감지를 이용한 하이브리드 충돌 방지 프로토콜)

  • Kim, Jeong-Hwan;Kim, Young-Tae;Park, Yong-Soo;Ahn, Kwang-Seon
    • Journal of Internet Computing and Services
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    • v.10 no.2
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    • pp.133-141
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    • 2009
  • A tag collision problem occurs when many tags are placed in a interrogation zone in RFID system. A tag collision problem is one of core issues and various protocols have been proposed to solve the collision problems. Generally tree-based protocols generate unique prefixes and identify tags with them as quick as possible. In this paper, we propose the QT-BCS protocol which decreases the identification time by reducing the number of query-response. The QT-BCS protocol makes a prefixes using time slot and bit change sensing unit. This protocol compares the current bit of tags until the current bit is differ from the previous one. When this occurs, all of the bits scanned so far are transferred to slot-0 and slot-1 depending on the first bit value in Reader. Consequently, this method can reduce the number of queries by tracing prefixes easily. Simulation result shows QT-BCS is more efficient in identifying tags than Query Tree and 4-ary Query Tree protocol.

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Improvement of Anti-collision Algorithm for RF Air-Interface Protocol (무선통신 프로토콜의 충돌방지 알고리즘 개선)

  • Lim, Jung-Hyun;Lee, Kwoun-Ig;Yang, Doo-Yeong;Kim, Heung-Soo;Ko, Jae-Kweon
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2007.02a
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    • pp.97-100
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    • 2007
  • 본 논문은 유비쿼터스 센서 네트워크와 텔레매틱스 서비스에 사용되는 무선 환경 프로토콜 표준 중 UHF 대역 프로토콜인 EPCglobal의 Class 1 Gen 1, Class 1 Gen 2의 에어인터페이스를 분석하고 각 프로토콜에서 규정된 충돌방지 알고리즘을 구현하였다. 그리고 각 프로토콜에서 규정하는 충돌방지 알고리즘의 성능을 개선한 알고리즘을 제안하고 성능을 비교하였다. 개선된 알고리즘과 표준 알고리즘의 성능 시뮬레이션 결과 개선된 Class 1 Gen 1 알고리즘은 태그 수 100개 일 때 54.5%, 태그 수 1000개 일 때 63.4% 감소하였다. 개선된 Class 1 Gen 2 알고리즘은 태그 수 100개 일 때 7.9%, 태그 수 1000개 일 때 11.7% 감소하였다. 개선된 충돌방지 알고리즘은 표준 알고리즘보다 태그 인식 성능이 상당히 개선됨을 알 수 있다. 따라서 개선된 충돌방지 알고리즘은 유비쿼터스 센서 네트워크와 텔레매틱스 서비스 등에 사용되는 무선인식 시스템의 성능 개선방안으로 적용될 수 있다.

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MAC Protocol for Fair Packet Transmission in CDMA S-ALOHA Systems (RFID 시스템에서 고속 태그식별을 위한 쿼리트리 프로토콜)

  • Yang Eui-Sik;Park Cheol-Woo;Lim In-Taek
    • Proceedings of the Korean Information Science Society Conference
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    • 2005.07a
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    • pp.496-498
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    • 2005
  • 본 논문에서는 RFID 시스템에서 식별영역 내에 있는 태그들을 식별하기 위하여 무기억 특성을 갖는 QT 프로토콜을 개선한 QT_rev 프로토콜을 제안한다. QT_rev 프로토콜에서는 질의 문자열이 식별코드의 처음 비트들과 일치하는 태그는 식별코드 중에서 질의 문자열을 제외한 나머지 비트들로만 응답한다. 또한 리더는 태그들의 응답 문자열 중에서 충돌이 발생한 비트 위치를 알 수 있으므로 충돌이 발생한 위치가 태그 식별코드의 마지막 비트이면 리더는 더 이상의 질의가 없이 두 개의 태그를 동시에 식별할 수 있다.

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Improvement of EPC Class-1 Anticollision Algorithm for RFID Air-Interface Protocol (무선인식 프로토콜의 EPC 클래스-1 충돌방지 알고리즘 개선)

  • Kang, Bong-Soo;Lim, Jung-Hyun;Kim, Heung-Soo;Yang, Doo-Yeong
    • The Journal of the Korea Contents Association
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    • v.7 no.4
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    • pp.10-19
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    • 2007
  • In this paper, Class-1 Air-interface protocols of EPCglobal applied to RFID system in UHF band are analyzed, and the standard anticollision algorithms are realized. Also, the improved anticollision algorithms of the Class-1 Generation-1 and Generation-2 protocol are proposed and the performances of anticollision algorithms are compared. As the results, reduction ratio of total tag recognition time of the improved Generation-1 algorithm is 54.5% for 100 tags and 63.4% for 1000 tags with respect to standard algorithm, respectively. And the reduction ratio of the improved Generation-2 algorithm is 7.9% for 100 tags and 11.7% for 1000 tags. Total recognition times of the improved algorithms are shorter than those of standard algorithms according to increasing the number of tag. Therefore, the improved anticollision algorithm proposed in this paper is the advanced method improving the performance of tag recognition in the RFID system.

A Revised QT Protocol for Tag Identification in RFID Systems (RFID 시스템에서 태그 식별을 위한 개선된 QT 프로토콜)

  • Lim, In-Taek;Choi, Jin-Oh
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.10 no.3
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    • pp.430-436
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    • 2006
  • In this paper, a QT_rev protocol is proposed for identifying all the tags within the identification range. The proposed QT_rev protocol revises the QT protocol, which has a memoryless property. In the QT_rev protocol, the tag will send the remaining bits of their identification codes when the query string matches the first bits of their identification codes. After the reader receives all the responses of the tags, it knows which bit is collided. If the collision occurs in the last bit, the reader can identify two tags simultaneously without further query. According to the simulation results, the QT_rev protocol outperforms the QT protocol in terms of the number of queries and the number of response bits.

Improvement of EPC Class-0 Anticollision Algorithm for RFID Air-Interface Protocol (무선인식 프로토콜에서의 EPC Class-0 충돌방지 알고리즘 개선)

  • Lim, Jung-Hyun;Jwa, Jeong-Woo;Yang, Doo-Yeong
    • The Journal of the Korea Contents Association
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    • v.8 no.3
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    • pp.18-24
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    • 2008
  • This paper analyzed Air Interface of EPCglobal's Class-0 that is UHF band protocol among radio environment protocol standard that is used to RFID system. And embodied prescribed anticollision algorithm in protocol. Also, the improved anticollision algorithm for the Class-0 protocol is proposed and performances of anticollision algorithm are compared. Result that compare performance of standard algorithm through simulation with improved algorithm, improved Class-0 algorithm when is tag number 100, reduced 8%, and when is tag number 1000, 12.2%. According as tag number increases, total realization time of improved algorithm decreased more gradually better than prescribed algorithm. Therefore, the improved anticollision algorithm proposed in this paper is advanced method improving the performance of tag recognition in the RFID system and Ubiquitous sensor network.

STAC/PS Algorithm with Tag Grouping by Transmission Power Control (송신 전력 제어에 의한 태그 그룹화 방법을 적용한 STAC/PS 알고리즘)

  • Lim, Intaek;Choi, Jinho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2016.10a
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    • pp.712-714
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    • 2016
  • The PS algorithm divides the tags within the identification range of reader into smaller groups by increasing the transmission power incrementally and identifies them. In 13.56MHz RFID system of Auto-ID center, STAC protocol is defined as an anti-collision algorithm for multiple tag reading. In this paper, we propose a STAC/PS algorithm that the PS algorithm is applied in the STAC protocol. The simulation results show that the STAC/PS algorithm can achieve faster tag identification speed compared with STAC protocol due to the low collision rate.

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