• Title/Summary/Keyword: tag collision

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A DFS-ALOHA Algorithm with Slot Congestion Rates in a RFID System (RFID시스템에서 슬롯의 혼잡도를 이용한 DFS-ALOHA 알고리즘)

  • Lee, Jae-Ku;Choi, Seung-Sik
    • The KIPS Transactions:PartC
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    • v.16C no.2
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    • pp.267-274
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    • 2009
  • For the implementation of a RFID system, an anti-collision algorithm is required to identify multiple tags within the range of a RFID Reader. There are two methods of anti-collision algorithms for the identification of multiple tags, conclusive algorithms based on tree and stochastic algorithms based on slotted ALOHA. In this paper, we propose a Dynamic Framed Slotted ALOHA-Slot Congestion(DFSA-SC) Algorithm. The proposed algorithm improves the efficiency of collision resolution. The performance of the proposed DFSA-SC algorithm is showed by simulation. The identification time of the proposed algorithm is shorter than that of the existing DFSA algorithm. Furthermore, when the bit duplication of the tagID is higher, the proposed algorithm is more efficient than Query Tree algorithm.

Hybrid anti-collision method for RFID System with the consideration of the average throughput (평균 처리율을 고려한 RFID 시스템의 하이브리드 충돌 방지 기법)

  • Choi, Sung-Yun;Lee, Je-Ho;Kim, Sung-Hyun;Tchah, Kyun-Hyon
    • Journal of IKEEE
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    • v.14 no.2
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    • pp.24-32
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    • 2010
  • Slotted-ALOHA and Binary-tree method are researched for the anti-collision for RFID system. However, it is required of the rapid recognition time for all tags and the reduction of the system complexity. In this paper. the hybrid anti-collision method is proposed to solve the problems. The RFID reader with the hybrid anti-collision method groups the tags with the number which makes the maximum system throughput, then it reads each group by slotted-ALOHA method. By the computer simulation results, it is found that the hybrid method improves the tag identification time and the system throughput together with the comparison to other anti-collision methods. Therefore, the proposed hybrid anti-collision method will enhance the RFID system performance.

Performance Improvements of DFSA(Dynamic Frame Slotted Aloha) Algorithm through Estimation of Intial frame Size (초기 프레임 크기 예측을 통한 DFSA(Dynamic Frame Slotted Aloha) 알고리즘 성능 개선)

  • Lee, Kang-Won;Lee, Moon-Hyung;Lee, Hyun-Kyo;Lim, Kyoung-Hee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.8
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    • pp.1517-1530
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    • 2017
  • Traditional anti-collision algorithms determine slot size of initial frame based on the information of number of collision slots, idle slots, and success slots. Since there is no information about collision at the beginning of tag information collection, traditional anti-collision algorithms can not determine the initial frame size. Considering that performance of anti-collision algorithm is very sensitive to initial slot size traditional anti-collision algorithms need some improvements. In this study two methods are proposed to determine slot size of initial frame efficiently, through which we can improve the performance of dynamic frame slotted aloha algorithm. To verify the performance of proposed algorithms, 2.4GHz RFID system is used. Throughput and delay time are derived through simulation, which is developed using JAVA. We have seen that proposed algorithm improves throughput by 9.6% and delay time by 9.8%.

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.

Pulse Protocol-based Hybrid Reader Anti-collision Algorithm using Slot-occupied Probability under Dense Reader Environment (밀집 리더 환경 하에서 슬롯 점유확률을 이용한 Pulse Protocol 기반의 Hybrid 리더 충돌방지 알고리즘)

  • Song, In-Chan;Fan, Xiao;Yoon, Hee-Seok;Chang, Kyung-Hi
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.10A
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    • pp.987-996
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    • 2008
  • In this paper, the conventional anti-collision algorithms, such as Channel Monitoring algorithm and Pulse Protocol algorithm are analyzed. To decrease tag identification time, and increase system throughput and efficiency, we propose a new reader anti-collision algorithm, Pulse Protocol-based Hybrid Reader Anti-collision Algorithm, using Slot-occupied Probability under dense reader environment. The proposed algorithm uses Slot-occupied Probability to improve the performance of Pulse Protocol Algorithm. That is, A reader checks Slot-occupied Probability after generating random backoff time. If Slot-occupied Probability is greater than 0, it uses another new random backoff time to avoid reader collision. We also compare the performance of the proposed algorithm with those of Channel Monitoring and Pulse Protocol algorithms in respect of identification time system throughput, and system efficiency. Simulation results show that the proposed algorithm has an increment of 5% of identification time and system throughput as increasing the number of readers.

Initial Slot-Count Selection Scheme with Tag Number Estimation in Gen-2 RFID System

  • Lim, In-Taek;Ryu, Young-Tae
    • Journal of information and communication convergence engineering
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    • v.8 no.5
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    • pp.519-523
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    • 2010
  • In Gen-2 RFID system, the initial value of $Q_{fp}$, which is the slot-count parameter of Q-algorithm, is not defined in the standard. In this case, if the number of tags within the reader's identification range is small and we let the initial $Q_{fp}$ be large, the number of empty slot will be large. On the other hand, if we let the initial $Q_{fp}$ be small in spite of many tags, almost all the slots will be collided. As a result, the performance will be declined because the frame size does not converge to the optimal point quickly during the query round. In this paper, we propose a scheme to allocate the optimal initial $Q_{fp}$ through the tag number estimation before the query round begins. Through computer simulations, it is demonstrated that the proposed scheme achieves more stable performance than Gen-2 Q-algorithm.

Accelerating RFID Tag Identification Processes with Frame Size Constraint Relaxation

  • Park, Young-Jae;Kim, Young-Beom
    • Journal of information and communication convergence engineering
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    • v.10 no.3
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    • pp.242-247
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    • 2012
  • In the determination of suitable frame sizes associated with dynamic framed slotted Aloha used in radio frequency identification tag identification processes, the widely imposed constraint $L=2^Q$ often yields inappropriate values deviating far from the optimal values, while a straightforward use of the estimated optimal frame sizes causes frequent restarts of read procedures, both resulting in long identification delays. Taking a trade-off, in this paper, we propose a new method for determining effective frame sizes where the effective frame size changes in a multiple of a predetermined step size, namely ${\Delta}$. Through computer simulations, we show that the proposed scheme works fairly well in terms of identification delay.

Performance Analysis of PS Algorithm with FIxed Frame Length (고정된 프레임 크기를 갖는 PS 알고리즘의 성능 분석)

  • Lim, Intaek
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2014.05a
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    • pp.547-549
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    • 2014
  • In RFID systems, the performance for the tag identification is closely related with the tag collision, which is caused by the simultaneous transmission. The PS algorithm divides the tags within the identification range of reader into smaller groups by increasing the transmission power incrementally and identifies them. This algorithm uses the fixed frame size at every scan. Therefore, it is anticipated that the performance of PS algorithm can be variously shown according to the number of tags, frame size, and power level increase. In this paper, we analize the performance of PS algorithm according to the frame length and power level increase.

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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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Simulation System for Anti-Collision Protocols in RFID (RFID 태그 충돌 방지 프로토콜의 성능 비교를 위한 시뮬레이션 시스템)

  • Shin Jae-Dong;Yeo Sang-Soo;Kim Sung-Kwon
    • 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.

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