• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5A
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• pp.358-366
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• 2012

LED-ID (Light Emitting Diode - Identification) is one of the key technologies for identification, data transmission, and illumination simultaneously. This is the new paradigm in the identification technology environment. There are many issues are still now challenging to achieve high performance in LED-ID system. Collision issue is one of them. Actually this is the most significant issue in all identification system. LED-ID system also suffers from collision problem. In our system, collision occurs when two or more readers transmit data to tag at the same time or vice versa. There are many anti-collision protocols to resolve this problem; such as: Slotted ALOHA, Basic Frame Slotted ALOHA, Query Tree, Tree Splitting, and Q-Algorithm etc. In this paper, we propose modified Q-Algorithm to resolve collision at tag. The proposed protocol is based on Q-Algorithm and used the information of arrived readers to a tag from neighbor. The information includes transmitting slot number of readers and the number of readers that can be arrived in next slot. Our proposed protocol can reduce the numbers of collision slot and the successful time to identify all readers. In this paper our simulation and theoretical results are presented.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.4
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• pp.43-51
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• 2010

In this paper, we studied line coding technology tendency for high speed data communication at LED-ID (Identification) communication system in indoor environment. A LED-ID technology is a communication using visible ray (RGB) that come out in LED device. It is energy curtailment effect and possible in ubiquitous network service applications. The LED-ID system has the above advantages about that the communication throughout the whole room is enabled by high power lighting and lighting equipment with white colored LED which are easy to install and have good outward appearance. Therefore, the transmission by light waves is more suitable for wireless networks than by radio waves. We compared with the NRZ, AMI, 4B5B, HDB3, 8B10B line coding for efficient in error detection and serves data transmission of high speed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.4
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• pp.411-417
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• 2014

In this paper, we propose an efficient OFDM(Orthogonal Frequency Division Multiplexing) frame synchronization scheme for LED-ID(Identification) systems. A frame synchronization is an essential procedure for normal operations of OFDM systems. Bernoulli-Gaussian noise is considered in LED-ID systems' environments. In order to enhance the OFDM frame synchronization performance, we add a ROGS(Repeated Orthogonal Gold Sequence) to OFDM signals in the time domain. The power level of a ROGS does not affect a normal operation of the LED-ID systems. Frame synchronization can be achieved successfully over LED-ID channels interfered by impulsive noise owing to good auto and cross-correlation properties of the ROGS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1586-1594
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• 2011

LED-ID (light emitting diode - identification) technology is the new paradigm in the identification technology environment. LED-ID system typically needs line of sight (LOS) that supports narrow FOV transceivers links to achieve high data rate. On the other hand, narrow FOV reduces the coverage area. Therefore, the number of tags is increased significantly to cover the whole area. In this case number of link switching is increased when the reader moves within whole coverage area. Link switching delay is the important factor for the moving reader to maintain the communication with high data rate and better QoS. In this paper we propose in literature a new link switching scheme and measure the link switching delay time for LED-ID system. The simulation results show that the proposed link switching scheme is a possible candidate for multi-tag LED-ID system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.2
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• pp.115-121
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• 2013

LED-ID (Light Emitting Diode-Identification) network is envisioned to be the next generation indoor wireless communication medium by which simultaneously high speed data transmission, identification, and illumination are possible. In spite of being extremely promising, it suffers from much impairment. Signals having different propagation paths can suffer from delays, and phase shifts which will eventually result interference. The probability of interference is also increased when communication links are established between a tag and several readers. Therefore it is necessary to reduce the interference in LED-ID network to ensure quality of service. It is possible to avoid interference by knowing the information about readers prior to assign the available spectrum. In this paper, we have proposed dynamic spectrum decision using cognitive radio concept. The simulation results justify that the proposed scheme is better than the conventional scheme.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.1
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• pp.66-74
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• 2013

This paper introduces the improvement of QoS to compensate the decreasing LED performance by temperature characteristic in the LED-ID communication system. LED does not only use as a lighting device, but also uses as a communication device. The conventional system is transmitted by RGB of LED following the mixture color ratio, which determined the color of lighting, and the BER performance of each RGB signals. However, when the LED used consistently, it has occurred the heat temperature. As a result, LED is degraded the performance by increased temperature each device. To solve this problem, we proposed the adaptive modulation and coding scheme by temperature of device to improve the performance of system and satisfied the QoS in the LED-ID system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.275-280
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• 2010

Recently, This paper suggests that LED-ID technique applying positioning method for LED light. also, Authors in this paper has launched this investigation earnestly. However, there are various interferences such as MPI(Multi Path Interference) by reflected waves of the surface and interfere factors by their correlation properties of the ID in LED-ID wireless channel. Therefore, in this paper, we propose a novel OOK(On-Off Keying)-CDMA(Code Division Multiple Access) system using unipolar ZCD(Zero Correlation Duration) spreading code and verify the availability of the proposed system via the evaluation performance simulation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.281-285
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• 2010

We propose new identification method of LED location in indoor environment. It can transmit and receive position information and additional data, as applying OOK-SS watermarking method for LED transmission signal. Especially, we use a unipolar form code for watermarking spread code, because LED signal has unipolar characteristic. we analysis LED signal influence and interference with watermarking code, demonstrate usefulness of LED-ID using OOK-SS Watermarking.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.10B
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• pp.1258-1267
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• 2011

In this paper, using the indoor LED-ID communication system have researched for how to transmit video signals. In LED-ID communications use the LEDs for lighting features at the same time communication is an effective way to implement. This proposed system using Visible light(RGB) as way to transmit signals, depends on the mixture RGB, which decided the color of light, moreover, each things determined their performance. However, if the video signal were fixed allocated RGB to transmit such as the original system, the importance of the each signals a different occur the limit on the quality of the video than SVC signals. In order to solve this problem in this paper, according to the RGB mixture ratios analyze the performance for the White LED, which analyzed based on allocating the SVC signal by transmitting to improve the quality of the video was about how researched.

• Journal of Satellite, Information and Communications
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• v.12 no.4
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• pp.157-161
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• 2017

Effective management of ULD (Unit Load Device) in Air Cargo Transportation is one of the Airline's main concerns. At present, the way of management of ULD which has the ID tag based on RFID is carried by cargo control staff with PDA. However, the activity of ULD management is limitted due to complexity of cargo terminal facilities. In this study, we offer the effective way of management of ULD by the DRONE equipped by LED-ID & RFID READER at the higher altitude in Air Cargo Terminal to recover the difficulty of identification due to complexity of terminal facilities. Further to the above, we suggest the operational effectiveness, limitation, and the direction of future research.