• Journal of Internet Computing and Services
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• v.8 no.4
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• pp.51-59
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• 2007

This paper presents the development of RFID educational system based on using 900MHz air interface between the reader and the active tag. The software of reader and the active tag is developed on embedded environment, and the software of PC controlling the reader is based on window OS operated as the server. The AT89C51ED2 VLSI chip is used for the processor of the reader and the active tag. As the development environment, Keil compiler is used for the reader and the active tag of which the programing language is C. The visual C language of the visual studio on the PC activated as the server is used for development language. To verify the function of the system, PC gets the tag's identification number through the reader and send the data to with the active tag memory a certain contents as "wite" operation. Finally the data written from the active tag's memory is sent to the PC via the reader as "read" operation and compare the received data with one already sent to the tag.

• The Journal of the Korea Contents Association
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• v.9 no.11
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• pp.90-99
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• 2009

This paper presents the implementation of RFID EPC global network educational system based on using 900MHz air interface between the reader and the active tag. The software of reader and the active tag is developed on embedded environment, and the software of PC controlling the reader is based on window OS operated as the server. The ATmega128 VLSI chip is used for the processor of the reader and the active tag. As the development environment, AVR compiler is used for the reader and the active tag of which the programming language is C. The visual C++language of the visual studio on the PC activated as the server is used for development language. Main functions of this system are to control tag containing EPC global Data by PC through the reader, to obtain information of tag through the internet and to read/write data on tag memory. Finally the data written from the active tag's memory is sent to the PC via the reader as "read" operation and compare the received data with one already sent to the tag. Software implementation of 900MHz EPC global RFID educational system is done on the basis of these functions.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.3
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• pp.211-221
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• 2023

This study was conducted as a basic study for the selection of tags suitable for logistics management in the palletized unit-load unit and the development of various technologies to activate the palletized unit-load shipment of agricultural products through local APCs. Three types of passive RFID tags of UHF 900 MHz and one type of active RFID tag of 2.4 GHz band designed and manufactured through this study were used to analyze the receiving strength according to the tag's attachment location and distance of the palletized unit-load of agricultural products. In the passive RFID tag, there was a large difference in receiving strength by the tag's attachment location and a large amount of data loss depending on the distance within 30 m, whereas, in the active RFID tag, it was superior to the passive tags in terms of both receiving strength and data loss. Therefore, active tags are desirable from the perspective of multiple identification of warehouses with large spaces in relation to the application of RFID tags for palletized unit-loads of agricultural products, but the development of low-power technologies such as software wakeup power management as well as hardware to minimize battery power consumption is necessary.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.7B
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• pp.518-527
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• 2008

Tag collection is one of the major functions in Radio Frequency Identification (RFID) systems. IS0/IEC 18000-7 defines the tag collection algorithm using the anti-collision algorithm, based on the framed slotted ALOHA for active RFID systems. However, it has inefficiency problems that reduce tag collection performance by deciding non-optimum slot size or using point-to-point commands to put collected tags to sleep. In this paper, we propose two mechanisms to overcome the inefficiency problems and improve tag collection performance: 1) a new slot size decision mechanism to allow the reader to choose the optimum slot size flexibly and 2) a broadcast-based sleep mechanism to put collected tags to sleep effectively. We also implemented an active RFID system, composed of an active RFID reader and multiple tags, and the reader is designed to maximize tag collection performance when the proposed mechanisms are applied. In experiments, we evaluated the tag collection performance using one reader and 50 tags in the real-world environment. The experimental results show that when two mechanisms are applied and the initial number of slots is chosen appropriately, the performance of the proposed tag collection algorithm is greatly enhanced, compared with that of the standard.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.3
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• pp.199-206
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• 2013

This paper proposes a modified tag collection algorithm that improves the drawback of the identified slot scan-based tag collection algorithm presented in a previous paper to improve the tag collection performance in active RFID systems. The previous identified slot scan-based tag collection algorithm is optimized in situations where all the tags store the fixed size of data, so it could not result in a good performance improvement with tags having the variable size of data. The improved tag collection algorithm proposed in this paper first collects the slot size information required for the data transmission from each tag via the identified slot scan phase, and then performs the tag collection phase using the information, which resolves the problem of the previous identified slot scan-based tag collection algorithm. The simulation results for performance evaluation showed that the proposed tag collection algorithm resulted in the almost same tag collection performance as the previous algorithm when all the tags have the same size of data and led a large improvement of the tag collection performance in ISO/IEC 18000-7 unlike the previous algorithm when each tag has a random size of data.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.7B
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• pp.686-693
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• 2009

In this paper, we propose an efficient tag sleep method utilizing empty time slots for improving the tag collection performance in active RFID systems. In the proposed tag sleep method, the reader detects the occurrence of empty time slots by carrier sensing and utilizes the wasted empty time slots to transmit sleep commands to the collected tags throughout the framed slotted aloha-based tag collection process, resulting in reducing the time required for tag collection. Via the simulation experiments, we evaluated the performance of the tag collection applied with the proposed tag sleep method, compared with that of the basic tag collection. The simulation results showed that the tag collection applied with the proposed tag sleep method could reduce the average tag collection time by 12.28%, 12.30%, and 13.31 %, for the framed slotted aloha with the fixed 128 time slots and 256 time slots, and the dynamic framed slotted aloha anticollision protocols, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.1
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• pp.1-11
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• 2013

Reducing the energy that consumed by tag is a key requirement for the wider acceptance of the active RFID systems that use battery constrained tags. When the reader is not interrogating, the active RFID standard protocols try to reduce energy consumption of tags by using sleep mode. On sleep mode tags is active by receiving a specific signals from reader, until tag receive a sleep mode command from the reader, a tag waste energy for remaining in RX mode. Overhearing is a state of a tag in which it wastes energy for maintaining active RX state while there is no frame destined to it. According to our analysis, the amount of energy consumed by a tag due to overhearing is several time larger than that consumed by the effective communication. We propose RANO(Reservation Aloha for No Overhearing) that is designed to inform a tag of its effective communication intervals to eliminate overhearing problem in active RFID communication. The performance of the proposed protocol was evaluated through the real world by changing the number of tags and size of data. The result of an experiment, the proposed protocol performed saving about 22 times less than the standard protocol did.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.12
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• pp.1013-1022
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• 2012

Tag collection is one of the major concerns in radio frequency identification(RFID) system. All tags in RFID reader's transmission range send response message back to the reader in response to collection request message on the given rf channel. When multiple tags respond simultaneously, tag-collision may occur. Tag-collision problem is one of the most important issues in active RFID performance. To mitigate this problem, frame slotted ALOHA(FSA) anti-collision protocol is widely used in active RFID system. Several studies show that the maximum system efficiency of FSA anti-collision protocol is 36.8%. In this paper, we propose an efficient slotted CSMA/CA protocol to improve tag collection performance. We compare our protocol to the FSA anti-collision protocol. For the experiment, an 433MHz active RFID system is implemented, which is composed of an RFID reader and multiple tags. We evaluated the tag collection performance using one RFID reader and 40 tags in the real test bed. The experimental result shows that proposed protocol improves the tag collection time, round and collision probability by 18%, 37.4% and 77.8%, respectively.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.3
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• pp.43-49
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• 2008

The Real Time Location System (RTLS) is very important in the ubiquitous society for real time tracking of men, high price assets, and logistics products. In this work, we developed an active RF system for RTLS and tested its performance. The RTLS system developed in this work was constructed of three active readers and one active tag. The small size tag developed in this work operated with a coin type battery. To make the tag smaller, we used an internal PCB antenna and a chip antenna. We tested the performance of the tag. To reduce the manufacturing cost of our RF system, we used low price RF transceiver CC2510 chip-set. The CC2510 chip-set provided RSSI(Received Signal Strength Indicator) signal which could be used to determine the distances between an active tag and three active readers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5B
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• pp.753-761
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• 2010

In this paper, we propose a novel tag collection algorithm to improve tag collection performance in active RFID systems. In the proposed algorithm, the reader detects the occurrence of empty slots and collided slots through the identified slot scan process and reduces the time wasted by empty slots and collided slots, resulting in improvement of tag collection performance. To evaluate the performance improvement by the proposed tag collection algorithm via the experiments in a real-world environment, we implemented an active RFID reader and tags. The experimental results with the reader and 60 tags showed that the proposed algorithm could reduce the average tag collection time by 21.7% and improve the average identification throughput by 28.3%, compared with the standard tag collection algorithm in ISO/IEC 18000-7. In addition, the proposed algorithm reduced the average battery consumption on tags by 22.7% in the battery consumption experiment with 20 tags.