• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8B
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• pp.822-829
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• 2009

A reader protocol is an interface between a host and RFID readers. There are several standards for reader protocol such as EPCglobal Low Level Reader Protocol (LLRP) 1.0.1, EPCglobal Reader Protocol (RP) 1.1, and ISO/IEC 15961/15962. Unfortunately, these standards focus on the passive RFID system, and so they are not appropriate for the active RFID system. In this paper, we implemented an efficient reader protocol for the active RFID system, which is based on EPCglobal LLRP 1.0.1, but smoothing/filtering functions of EPCglobal RP 1.1 are added. This protocol is designed to configure air interface parameters for active RFID readers and tags. It can reduce the amount of data transfer between the reader and host by filtering function, and can improve the performance of tag collection by smoothing function. In addition, it can remove inefficiency caused by tag memory data change according to the standards of ISO/IEC 15961/15962. In the real-world environment, we evaluated the performance of our implemented reader protocol using one RFID reader and 45 tags.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.10B
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• pp.1159-1167
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• 2011

In this paper, we proposed and implemented an EPCglobal Reader Manegement (RM) based management protocol. Using RFID Reader's management function, we could diagnose an active RFID Reader concretely which was impossible with only using Reader protocols and check the problem quickly when the RFID Reader is in failure. When diagnosing RFID Readers using the proposed RM based management protocol, we can check on their failure in stages and specifically, and can estimate range of failure. This helps RFID Reader's fast recovery, reduce loss of failure and improve QoS. We could get reader information with almost same overhead compared with the management message in LLRP. And we could get more information about RFID Reader's operation status.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2B
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• pp.279-286
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• 2010

RFID reader protocol is an interface between RFID readers and higher (host) such as RFID middlewares and applications. At present, reader protocols provided by vendors are different from each other and there are compatibility problems in environment using heterogeneous readers. In this paper, to solve this problem, an RFID reader which supports LLRP(Low Level Reader Protocol), a well-known standard reader protocol presented by EPCglobal is designed and implemented. It is designed with two modules and supports various interfaces for easy adaptation to various applications. The LLRP protocol is implemented over a embedded LINUX multi-thread environment. It not only supports almost all properties of LLRP, and is designed with flexible hardware/software architecture to meet various requirements.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.752-760
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• 2010

This paper investigates the performance of EPCglobal Generation-2(Gen-2) radio frequency identification(RFID) protocol under reader-to-reader interfering environments. We establish a modified discrete-time Markov chain(DTMC) model for the Gen-2 and accordingly obtain quantitative results of query success rate(QSR) and tag identification speed (TIS). Extensive simulations validate our theoretical analysis and demonstrate that the number of tags over 100 has little impact on the performance. TIS linearly decreases by 10 tags/sec/reader as the number of interfering readers increases. Our model for Gen-2 protocol is also useful to study the performance of other RFID protocols.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.6 s.121
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• pp.602-611
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• 2007

In this paper, the forward link of UHF RFID system is modeled in accordance with the EPCglobal class 1 generation 2(EPCglobal C1G2) UHF Radio-Frequency Identity protocol specification at $860{\sim}960MHz$. Based on the constructed model, characteristics on the forward link signal for the EPCglobal C1G2 RFID reader are simulated with the help of a MATLAB softwarein order to extract the design parameters of a transmit digital filter which meets the Korean RFID regulations. Herein, the forward link model is consisted of PIE source coding, transmit digital filter, modulation, local oscillator, and antenna. From the simulation results, the ranges of three design parameters(roll-off factor, cutoff frequency, the number of tabs) for transmit digital filter are obtained with different modulation techniques and the Tari(type a reference interval) values. Finally, DSB/SSB-ASK modulation technique can not satisfy the EPCglobal C1G2 specification when Tari equals to $6.25{\mu}sec$ in a multiple-reader environment. Consequently this paper can provide a guideline for design parameters of a RFID reader as well as the basic scheme of analyzing frequency interference problems in RFID environments, including multiple-reader and dense-reader environments.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.8
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• pp.842-852
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• 2010

RFID applications use tags to identify objects, but recent applications tend to include diverse sensor devices such as light, temperature, and humidity sensors as well. RFID tag information is usually processed via the event driven model. However sensor devices are usually accessed via the functional call model. Therefore application developers have to deal with mixed data access models and device dependent interface functions. In this paper, we propose a sensor reader emulator that provides a consistent access interface to sensor devices regardless of the types of devices. SRE provides a more efficient way of developing RFID applications by providing a single application programmer's view to RFID tags and sensor devices. In applications where tags are fixed to a place, SRE can replace expensive sensor tags and sensor readers with inexpensive sensor devices reducing the total cost while providing the same functionality.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.5
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• pp.12-20
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• 2008

RFID(Radio frequency indentification) technology, that the reader detect the tag information attached on the objects without contact, is considered the kernel of realizing tile Ubiquitous Sensor Network. Particularly, because there are lots of tags(which the reader have to detect) in the UHF RFID system(that is applied at the Logistic & Distribution industry). In the UHF RFID system the negative effects, we called the tag-collision, may occur and we should solve these effects. So, in the EPCglobal Gen2 protocol they present the Slotted Random Anti-collision algorithm to prevent the tag-collision effect. In this paper, in order to minimize the tag-collision effect and bring on the system efficiency, we propose the Power Increasing Method that controls the transmission power of the reader depending on the environment and verily the improved performance.

• Journal of information and communication convergence engineering
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• v.8 no.3
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• pp.307-311
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• 2010

EPCglobal Class-1 Gen-2 protocol has been proposed for UHF-band RFID systems. In Gen-2 standard, Q-algorithm was proposed to select a frame size for the next query round without estimating the number of tags. Therefore, the Q-algorithm has advantage that the reader's algorithm is simpler than other algorithms. However, it is impossible to allocate the optimized frame size. Also, the original Q-algorithm did not define an optimized parameter C for adjusting the frame size. In this paper, we propose an adaptive Q-algorithm with the different parameter $C_c$ and $C_i$ in accordance with the status of reply slot. Simulation results show that the proposed adaptive Q-algorithm outperforms the original Gen-2 Q-algorithm.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.6
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• pp.51-61
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• 2007

In this paper, Air-interface protocols of ISO 18000-6 Types and EPCglobal Classes applied to RFID system in UHF band are analyzed, and those anticollision algorithms are realized. Also, the each algorithm which improves the performance of standard protocol is proposed, and the performance is compared when clock period of link timing is a identical condition on $12.5{\mu}s$. As the result, when 500 tags exist simultaneously inside reader interrogation zone, the tag recognition performance of a standard protocol is better in preceding order of Class-1 Generation-1, Type B, Type A, Class-0 and Class-1 Generation-2. And also the performance of improved protocol is better in ascending order of Type B, Type A, Class-1 Generation-1, Class-0 and Class-1 Generation-2. Therefore, performance of tag recognition remarkably depends on the regulated clock period in the protocol and link timing between a reader and a tag.

• The Journal of the Korea Contents Association
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• v.9 no.4
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• pp.55-64
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• 2009

For realizing ubiquitous computing, many research activities are geared towards various areas including embedded computing, RFID, USN, home networking, context-awareness, and etc. By using the ability of RFID technology to recognize a number of objects simultaneously, more convenient ubiquitous application services are effectively provided. In this case, RFID middleware playing a role as a bridge between RFID reader devices and application services is required as well. In this paper, we propose a method of handling a number of types of RFID reader devices in ALE middleware of EPCglobal. For this, the information of connection and data protocol for a reader device is stored in a database as ontology meta-data, and used to interpret the data read by a reader device. By adding ontology data into a database, even though an RFID device newly emerges, ALE middleware can not only handle the device, but also be effectively extended through reusing ontology data, without any changes in the middleware.