• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6B
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• pp.544-552
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• 2003

This paper suggests an instruction code sufficiency algorithm preventing data collision when multiple transponders attempt to connect in the radio frequency identification system. Conventional time domain procedure generates unconditional collision. On the other hand, this algorithm prevents data collision by transmitting data when it meets instruction code. When multiple transponders are transmitting data coincidently, they exploit desired data with using difference of arrival time generated by recognition distance, respectively. As a result of simulation, utilizing the wireless recognition system, adopting the suggested algorithm, operating in 13.56MHz frequency band, it verify that there is Anti-collision and data loss by ensuring transmission time difference of one bit by adopting this algorithm.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.1 s.343
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• pp.41-48
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• 2006

An anti-collision algorithm is very important in the RFID system because it decides tag identification time and tag identification accuracy. We propose improved anti-collision algorithms using Bin slot in RFID system. In the proposed algorithms, if the reader memorizes the Bin slot information, it can reduce the repetition of unnecessary PingID command and the time to identify tags. If we also use ScrollA11ID command in the proposed algorithm, the reader knows the sequence of collided E bits. Using this sequence, the reader can reduce the repetition of PingID command and tag identification time. We analyze the performance of the proposed anti-collision algorithms and compare the performance of the proposed algorithms with that of the conventional algorithm. We also validate analytic results using simulation. According to the analysis, for the random tag n, comparing the proposed algorithms with the conventional algorithm, the performance of the proposed algorithms is about $130\%$ higher when the number of the tags is 200. And for the sequential tag ID, the performance of the conventional algorithm decreases. On the contrary, the performance of the proposed algerian using ScrollA11ID command is about $16\%$ higher than the case of using random tag ID.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8A
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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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5C
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• pp.540-547
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• 2006

This paper proposes a novel anti-collision method for the ISO/IEC 18000-6 type B protocol which is the standard protocol of the 900 MHz RFID system. We improve the anti-collision performance by reducing the transmission number of commands and the length of bits required for multi-tag identification in the ISO/IEC 18000-6 type B protocol. Simulation results show that the proposed method improves the multi-tag identification time by 21.7% over the conventional method, irrespective of number of tags.

• International Journal of Contents
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• v.2 no.1
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• pp.34-38
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• 2006

In this paper, an overview of anti-collision algorithm for RFID system of a standard EPC Class1 protocol is presented, and the binslotted dynamic search algorithm (BDS) based upon the slotted ALOHA and binary tree procedure is proposed and analyzed. Also, the performance is evaluated as comparing the BDS algorithm with the standard bin-slotted algorithm (BSA) through the simulation program. The performance of the proposed BDS algorithm is improved by dynamically identifying the collided-bit position and the collided bins stored in the stack of the reader. As the results, the number of request command that a reader send to tags in the reader s interrogation zone and the total recognition time are decreased to 59% as compared with BSA algorithm. Therefore, the tag identification performance is fairly improved by resolving a collision problem using the proposed BDS algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.1
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• pp.57-67
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• 2013

Because many of the FOB key, anti-collision algorithm for a seamless multi-access is applied to the smart-key system. In this paper, we have designed and implemented improved anti-collision algorithm that dramatically reduces the communication response time required in the user authentication process immediately after by dynamically changing the order in which the request of the user ID as the user ID on immediately before in the smart key system for vehicles that use many of the FOB key. In order to evaluate the performance of the system the improved anti-collision algorithm is applied, we show the behavior of the algorithm implemented in the state actually mounted on the vehicle and verify that communication response time required for many of the FOB key was reduced by about 33% compared to existing algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8A
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• pp.794-804
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• 2008

In this paper, we analyze the performance of probabilistic slotted anti-collision algorithm used in EPCglobal Class-1 Generation-2 (Gen2). To increase throughput and system efficiency, and to decrease tag identification time and collision ratio, we propose new tag anti-collision algorithms, which are FAFQ (fired adjustable flamed Q) algorithm and AAFQ (adaptive adjustable framed Q) algorithm, by using QueryAdjust command. We also propose grouping method based on Gen2 to improve the efficiency of tag identification. The simulation results show that all the proposed algorithms outperform Q algorithm, and AAFQ algorithm performs the best. That is, AAFQ has an increment of 5% of system efficiency and a decrement of 4.5% of collision ratio. For FAFQ and AAFQ algorithm, the performance of grouping method is similar to that of ungrouping method. However, for Q algorithm in Gen2, grouping method can increase throughput and system efficiency, and decrease tag identification time and collision ratio compared with ungrouping method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.5
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• pp.2294-2309
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• 2020

In this article, a new Aloha-based tag identification protocol is presented to improve the reading efficiency of the EPC C1 Gen2-based UHF RFID system. Collision detection (CD) plays a vital role in tag identification process which determines the efficiency of anti-collision protocols since most Aloha-based protocols optimize the incoming frame length based on the collisions in current frame. Existing CD methods are ineffective in identifying collision, resulting in a degradation of identification performance. Our proposed algorithm adopts an enhanced CD (ECD) scheme based on the EPC C1 Gen2 standard to optimize identification performance. The ECD method can realize timely and effective CD by detecting the pulse width of the randomly sent by tags. According to the ECD, the reader detects the slot distribution and predicts tag cardinality in every collision slot. The tags involved in each collision slot are identified by independently assigned sub-frames. A large number of numerical results show that the proposed solution is superior to other existing anti-collision protocols in various performance evaluation metrics.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.8
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• pp.1619-1624
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• 2012

If multiple Tags in the RFID System transmit their IDs to the Reader at the same time, tag identification time is delayed due to collisions. Therefore, to reduce the reader's identification time, an efficient anti-collision technology is needed. In this paper, we propose a hybrid anti-collision method based on the QT and DFSA. Then, the performances of proposed method are compared with the existing method through extensive simulations.