• Journal of the Korea Society of Computer and Information
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• v.11 no.6 s.44
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• pp.249-260
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• 2006

This study is to investigate how mobile internet service users recognize that Wibro service providers should be equipped with what type of organizational capabilities. Especially. this stud y, in exploratory point of view, examines the recognition is differed by characteristics of Wibro service users. This study also is to suggest a few of research propositions regarding the relations hips between organizational capabilities and characteristics of Wibro service users from various statistical analyses. To accomplish these research purposes, this study defined characteristics of Wibro service users (sender, age, job) and organizational capabilities of Wibro service provide rs ( accounting/finance capabilities, production/service capabilities, marketing/sales capabilities. research and development/technology capabilities) based on the review of past mobile interne t service related studies. And then, this study performed not only questionnaire survey on latent Wibro service users but also various statistical analyses.

• Journal of Digital Contents Society
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• v.7 no.3
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• pp.161-168
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• 2006

Wibro(Wibro - Wireless Broadband Internet ) is a system that can accept effectively the IP-based Wireless data traffic with upward / downward asymmetric transfer characteristic by using a Wirelss broadband transfer technology in OFDMA/TDD (Orthogonal frequency Division Multiple Access/Time Division Duplex). Wibro service should support handover to maintain connection continuously in movement because the service is based on If system which is different from cellular system. Current Micro Mobility system and general Mobile If system has got a problem of delayed speed and lost packets during handover. IETF protocol has been proposed for minimizing this problem and its standardization is under process, mainly focused on Mip4, Mip6 and Mipshop WG. This article studies and analyzes an effective method of minimizing handover delay to improve the problem of WiBro system and its revitalization & outlook.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.89-92
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• 2005

For the past years, wireless communications environment have developed with explosive demand of internet service and increase of subscriber. Anytime anywhere, we can access internet service and recently, we can access internet with portable terminal using wireless communications. So several schemes have been proposed for the efficient service. In this paper, we may improve performance of wibro system using adaptive antennas scheme at the base station (BS) and mobile station(MS),operating jointly. In wibro system, the joint use of transmit beamforming at BS and receive beamforming at MS is improved the SINR and increased the capacity compared to conventional system[1],[2].

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.981-985
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• 2006

Wibro is stand for Wireless Broadband Internet called as Portable Internet, Wireless Broadband Internet or Wireless High-Speed Internet. This provides hish-speed internet service anytime, anywhere, from anyone and device with seamless mobility and the band is located between Mobile phone and wireless LAN. Wibro service should support handover to maintain connection continuously in movement because the service is based on If system which is different from cellular system. Current Mitre Mobility system and general Mobile If system has got a problem of delayed speed and lost packets during handover. IETF protocol has been proposed for minimizing this problem and its standardization is under process, mainly focused on Mip4, Mip6 and Mipshop WG. This article studies and analyzes an effective method of minimizing handover delay to improve the problem of WiBro system and its revitalization & outlook.

• Journal of IKEEE
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• v.16 no.3
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• pp.159-166
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• 2012

In this paper, we designed and implemented the MIMO (Multiple-Input Multiple-Output) antenna for the mobile handset that could be used for multiple services. Simulation results were obtained using SEMCAD X by SPEAG based on the FDTD (Finite Difference Time Domain) Method which showed that S11 values were less than -6 dB (VSWR < 3) for LTE (Long Term Evolution) 700/2300/2500, K-PCS (Korea-Personal Communication Service : 1,750 ~ 1,870 MHz), US-PCS (US-Personal Communication Service : 1,850 ~ 1,990 MHz), Wibro (2,300 ~ 2,390 MHz), Bluetooth (2,400 ~ 2,483 MHz), and US-WiMAX (US-World interoperability for Microwave Access: 2,400 ~ 2,590 MHz) frequency bands. Measured results of the fabricated antenna also showed that it could be used for LTE 700/2300/2500, K-PCS, US-PCS, Wibro, Bluetooth, and US-WiMAX. services.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.459-462
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• 2008

By using RFID technology in order to manage public traffic management, RFID system and middleware software with PXA255 ARM chip is developed and is capable of operating the traffic card. The developed RFID system consists of 13.56MHz RFID R/W, wireless LAN (IEEE802.11.a/b), Wibro (IEEE802.16), TFT-LCD to display information, and embedded system to collect a charge information, etc. By applying developed system, basic infra-structure capable of supporting various service of u-Traffic can be effectively applied.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.197-200
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• 2009

Since various type of wireless/mobile network likes WLAN, WIBRO, HSDPA were come to us, technology providing high quality multimedia service while user move are actively researched such as MIH (Media Independent Handover) proposed by IEEE for interworking between heterogeneous network and CMIP (Client Mobile IP), PMIP (Proxy Mobile IP) for mobility. Despite the technology about interworking and handover between heterogeneous network are actively researched, handover decision method need to be researched. In this paper we suggest a simple and effective handover method for high quality multimedia service in real wireless environment. For this, we use MIH+CMIP platform for target multimedia service to make handover decision rule in WIBRO and HSDPA networks. After apply this rule, we verified effectiveness of handover decision method through real test.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.141-148
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• 2006

This paper deals with the performance improvement by eliminating loop interference signal and inserting adaptive equalizer for phase compensation in OFDMA based Wibro relay station. The Wibro relay station is used for the extension of communication service area and for throughput improvement of base station. The loop interference is important factor of performance determination of relay station when transmitter and receiver is very closely located. In order to design interference canceller, we generated base-band OFDMA signal and then transmitted the signal along with pilot tones alined with two different combinations for training mode. And then, we generated received fading signal due to the loop interference added noise to the received signal. In the receiver, the transmitted signal is recovered by elimination of the interference signal with channel estimate and compensating phase by adaptive equalizer. The performance improvement was verified by computer simulation which show channel estimation, constellation of signal and BER characteristics according to the variation of SNR ratio.

• Journal of Advanced Navigation Technology
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• v.11 no.3
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• pp.306-312
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• 2007

Present TCP/IP networks have some service quality problems. They delay various kinds of traffic, while increased traffic bottle necks, a phenomena experienced by too many internet users. Therefore, as use of the network increases, building up a stable network service is needed. Thus, network managers desperately need the best, most effective traffic control and wide-band services. Until now there has been no other way of increasing wide-band use of lines, particularly because of the expenses a limit solutions of solving continuously to increasing traffic problems. This study suggests a problem solving method under the base of 802.16e(Wibro) which will be widely used in the future.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.10 no.2
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• pp.27-40
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• 2006

WiBro will speed up Ubiquitous era that will have positive effects in our economy such as increase in general production, consumer spending, general export, service qualify, and employment rate. Considering the fact that Wibro is currently commercialized in only few selected countries, Korea has advantage in standardizing technology, accumulating the related know-how, producing domestic parts, and technology marketing experience. I believe developing Wibro technology in Korea will deliver a significant amount of contribution to the future IT technology.