• Title/Summary/Keyword: Anti-collision 알고리즘

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EMQT : A Study on Enhanced M-ary Query Tree Algorithm for Sequential Tag IDs (연속적인 태그 ID들을 위한 M-ary 쿼리 트리 알고리즘의 향상에 관한 연구)

  • Yang, Dongmin;Shin, Jongmin
    • 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.

A Study on Optimization Problem based on RFID Reader-to-reader Interference Model and Genetic-resource Allocation Technique (RFID 리더간 간섭 모델에 기반 한 최적화 문제와 유전적 자원할당 기법에 관한 연구)

  • Seo, Hyun-Sik;Lee, Chae-Woo
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.46 no.4
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    • pp.51-60
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    • 2009
  • In radio frequency identification(RFID) systems, when an RFID reader uses the same or adjacent frequency with neighbor readers, the interference between the readers may occur, which causes the reader collision and errors in tag recognition. In the previous study on RFID reader anti-collision, the techniques based on Frequency Division Mutiplex(FDM) or Time Division Multiplex(TDM) are proposed. However in these paper, the problem on the condition of RFID reader-to-reader interference considering the distance between interfering readers, frequency and operating time is not define exactly. In this paper, the interference effect is analyzed through RFID reader interference model considering the TDM and FDM, and the optimization problem is defined. To solve this, genetic-resource allocation technique is proposed. Therefore the optimal resource allocation applied RFID environment faithfully is accomplished.

Performance Analysis of FSA Algorithm for Tag Identification in RFID Systems (RFID 시스템에서 태그 식별을 위한 SFSA 알고리즘의 성능 분석)

  • Lim, In-Taek;Choi, Jin-Oh;Choi, Jin-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2008.05a
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    • pp.563-566
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    • 2008
  • In RFID system. when a variety of tags are present in the interrogation zone of a single reader at the same time, the system requires a multiple tag identification scheme that allows the reader to read data from the individual tags. Anti-collision algorithms required for the multiple tag identification are essential for the implementation of RFID system. This paper analyzed the performance of SFSA algorithm, which is easy to implement. According to the analytical results, the algorithm's performances are closely related with the number of tags and the frame size.

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Frame Selection Algorithm for the RFID system (RFID 시스템을 위한 프레임 선택 기법)

  • Lee Ju-No;Joe In-Whee
    • Proceedings of the Korean Information Science Society Conference
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    • 2006.06d
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    • pp.55-57
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    • 2006
  • 최근 국내 표준의 확정과 함께 새로운 수익모델로써 다양한 분야에서 활용이 기대가 되는 RFID 무선인식 시스템은 국내의 많은 업체와 기관들이 현재 다양한 솔루션을 개발함으로써 다가오는 유비쿼터스 환경에 적극 대응하고 있다. RFID 시스템의 중요한 기술요소 중 하나는 다중 태그로 인한 충돌을 처리하는 Anti-collision 알고리즘이다. 본 논문에서는 먼저 충돌방지기법의 종류와 최근에 900MHz대역의 RFID 표준으로 확정된 ISO/IEC 18000-6 Type C 표준문서에서 소개한 Slotted random 충돌방지 알고리즘을 분석하고, 충돌 정도에 따라 적응적으로 다음 프레임의 크기를 조정하는 기법을 제안한다. 모든 태그를 완전히 읽어내는데 걸리는 시간을 계산하기 위해서 Type C 표준을 적용한 모의실험을 통해 성능평가를 하였다.

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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.

Design of Digital Codec for EPC RFID Protocols Generation 2 Class 1 Codec (EPC RFID 프로토콜 제너레이션 2 클래스 1 태그 디지털 코덱 설계)

  • Lee Yong-Joo;Jo Jung-Hyeon;Kim Hyung-Kyu;Kim Sag-Hoon;Lee Yong-Surk
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.3A
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    • pp.360-367
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    • 2006
  • In this paper, we designed a digital codec of an RFID tag for EPC global generation 2 class 1. There are a large number of studies on RRD standard and anti-collision algorithm but few studies on the design of digital parts of the RFID tag itself. For this reason, we studied and designed the digital codec hardware for EPC global generation 2 class 1 tag. The purpose of this paper is not to improve former studies but to present the hardware architecture, an estimation of hardware size and power consumption of digital part of the RFID tag. Results are synthesized using Synopsys with a 0.35um standard cell library. The hardware size is estimated to be 111640 equivalent inverters and dynamic power is estimated to be 10.4uW. It can be improved through full-custom design, but we designed using a standard cell library because it is faster and more efficient in the verification and the estimation of the design.

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.

An Efficient Evolutionary Algorithm for Optimal Arrangement of RFID Reader Antenna (RFID 리더기 안테나의 최적 배치를 위한 효율적인 진화연산 알고리즘)

  • Soon, Nam-Soon;Yeo, Myung-Ho;Yoo, Jae-Soo
    • Proceedings of the Korea Contents Association Conference
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    • 2009.05a
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    • pp.715-719
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    • 2009
  • Incorrect deployment of RFID readers occurs reader-to-reader interferences in many applications using RFID technologies. Reader-to-reader interference occurs when a reader transmits a signal that interferes with the operation of another reader, thus preventing the second reader from communicating with tags in its interrogation zone. Interference detected by one reader and caused by another reader is referred to as a reader collision. In RFID systems, the reader collision problem is considered to be the bottleneck for the system throughput and reading efficiency. In this paper, we propose a novel RFID reader anti-collision algorithm based on evolutionary algorithm(EA). First, we analyze characteristics of RFID antennas and build database. Also, we propose EA encoding algorithm, fitness algorithm and genetic operators to deploy antennas efficiently. To show superiority of our proposed algorithm, we simulated our proposed algorithm. In the result, our proposed algorithm obtains 95.45% coverage rate and 10.29% interference rate after about 100 generations.

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Adaptive CFAR implementation of UWB radar for collision avoidance in swarm drones of time-varying velocities (군집 비행 드론의 충돌 방지를 위한 UWB 레이다의 속도 감응형 CFAR 최적화 연구)

  • Lee, Sae-Mi;Moon, Min-Jeong;Chun, Hyung-Il;Lee, Woo-Kyung
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.25 no.3
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    • pp.456-463
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    • 2021
  • In this paper, Ultra Wide-Band(UWB) radar sensor is employed to detect flying drones and avoid collision in dense clutter environments. UWB signal is preferred when high resolution range measurement is required for moving targets. However, the time varying motion of flying drones may increase clutter noises in return signals and deteriorates the target detection performance, which lead to the performance degradation of anti-collision radars. We adopt a dynamic clutter suppression algorithm to estimate the time-varying distances to the moving drones with enhanced accuracy. A modified Constant False Alarm Rate(CFAR) is developed using an adaptive filter algorithm to suppress clutter while the false detection performance is well maintained. For this purpose, a velocity dependent CFAR algorithm is implemented to eliminate the clutter noise against dynamic target motions. Experiments are performed against flying drones having arbitrary trajectories to verify the performance improvement.

A Combined Polling and Random Access Technique for Enhanced Anti-collision Performance in RFID Systems (폴링과 랜덤접속모드을 통합한 RFID 충돌방지 프로토콜)

  • Baeck, Ki-Kyung;Shin, Woo-Jin;Kim, Jeong-Geun
    • Proceedings of the Korea Information Processing Society Conference
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    • 2007.05a
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    • pp.875-876
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    • 2007
  • 본 논문에서는 지능적으로 폴링과 랜덤접속모드를 사용하는 RFID 충돌방지 기법을 제안하고자 한다. 본 논문에서 제안하고자 하는 충돌방지 알고리즘은 태그의 교체율이 크지 않을 경우, 먼저 이전 인식과정에서 성공적으로 식별한 태그들에 대한 고유정보를 기억한 뒤 다음 인식 세션에서 그 고유 정보를 활용하여 출석을 부르는 것처럼 경쟁 없이 태그들을 호출하여 빠르게 식별한다. 이전 세션(session)에 비하여 많은 수의 태그가 교체되었으면 인식률이 저하될 수 있다. 이 경우에는 랜덤 접속모드로 전환하여 나머지 태그들을 읽어 낸다. 본 논문에서 제안하는 것처럼 인식이력을 활용한 모드와 랜덤 접속 모드를 적절히 조합하여 운용하면 태그 인식 시간을 단축할 수 있으며, 특히, 주기적으로 개체의 존재 유무를 확인하는 응용의 경우에 우수한 성능 향상을 얻을 수 있다.

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