• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.1
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• pp.35-42
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• 2010

Geo-location using a cellular network is a core technology for LBS together with GPS. With preamble symbols broadcasted in each frame, geo-location using WiBro network can be easily implemented. Because the WiBro network has a cellular structure, it is difficult for a mobile station to detect signals from multiple base stations. In order to get user position using trilateration, long integration techniques for sensitivity enhancement should be employed. This paper presents hybrid integration scheme for WiBro network. By analyzing coherent and non-coherent integration loss according to frequency residual and SNR respectively, optimal combination of the hybrid integration is proposed. Simulation results show that the hybrid integration method is profitable in WiBro network when the frequency residual is estimated and compensated accurately.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.5
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• pp.565-573
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• 2016

Wi-Fi Direct standard technology(Wi-Fi Peer to Peer Technical Specifications v1.2, 2010) was designed for allowing peer to peer communication between two or more devices and various products which have been currently manufactured such as smart phone and smart TV have already provided this technical function. In this technology the role of Coordinator in Wi-Fi infrastructure would be matched to GO(Group Owner) which needs relatively high energy resource and computation power due to the high probability for allowing 3rd-party connection, however, the current standard specification would be limited in terms of energy distribution because it has not included a process to determine the role of GO. To address above problem, this paper classified considerable parameters into the general parameters for the physicality of devices and the specific parameters for considering the role position depending on use-case scenario, and proposed a new method called DIVA to help efficiently determining GO role from the member devices of Wi-Fi Direct network. Furthermore the effect of this mechanism was proved via simulation-based experiments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.1250-1264
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• 2017

This paper presents the architecture design, implement, experimental validation of a bistatic backscatter wireless communication system in Wi-Fi network. The operating principle is to communicate a tag's data by detecting the power level of the power modulated Wi-Fi packets to be reflected or absorbed by backscatter tag, in interconnecting with Wi-Fi device and Wi-Fi AP. This system is able to provide the identification and sensor data of tag on the internet connectivity without requiring extra device for reading data, because this uses an existing Wi-Fi AP infrastructure. The backscatter tag consists of Wi-Fi energy harvesting part and a backscatter transmitter/a power-detecting receiver part. This tag can operate by harvesting and generating energy from Wi-Fi signal power. Wi-Fi device decodes information of the tag data by recognizing the power level of the backscattered Wi-Fi packets. Wi-Fi device receives the backscattered Wi-Fi packets and generates the tag's data pattern in the time-series of channel state information (CSI) values. We believe that this system can be achieved wireless connectivity for ultra- low-power IoT and wearable device.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.479-482
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• 2012

WiBro(Wireless Broadband) service is the world standardized fourth-generation communications in Korea. The services through internet-based applications using WiBro communication-based is increasing. WiBro service in the Internet-based applications when using the service, the application may need to analyze the vulnerability. In this paper, we use the Internet when in WiBro service, to analyze the vulnerability. And, Internet-based applications for vulnerabilities that could lead to hacker attacks is analyzed. It will be studied that security measures through analysis of vulnerability of WiBro services and applications.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.6
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• pp.1217-1222
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• 2012

WiBro(Wireless Broadband) service is the world standardized fourth-generation communications in Korea. The services through internet-based applications using WiBro communication-based is increasing. WiBro service in the Internet-based applications when using the service, the application may need to analyze the vulnerability. In this paper, we use the Internet when in WiBro service, to analyze the vulnerability. And, Internet-based applications for vulnerabilities that could lead to hacker attacks is analyzed. It will be studied that security measures through analysis of vulnerability of WiBro services and applications.

• Journal of Advanced Navigation Technology
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• v.10 no.4
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• pp.306-311
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• 2006

When the WiBro/WLAN hierarchical network is structured, a dual mode access terminal should keep WLAN module with power on state for operating in WiBro network outside of WLAN hotspot zone. Power consumption of user's access terminal can be increased to maintain WLAN module power on state of dual mode access terminal in WiBro network outside of the hotspot zone. This paper focuses on power saving strategy for a dual mode access terminal in WiBro/WLAN Hierarchical network to overcome problems regarding power. We will apply information about hotspot in WiBro network to establish the efficient power saving strategy for dual mode access terminal.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.203-207
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• 2009

WiBro(Mobile WiMAX) has gained momentum as a top candidate to deliver the dream of full mobile wireless internet. To save cost and time in WiBro network design, simulation tool has to deploy powerful and useful analysis functions. If path loss model is more accurate, the reliability of analysis result of simulation tool will be much improved. So we emphasize on the importance of pathloss model in WiBro network design in this paper. For this, we introduce to three kinds of pathloss models(SUI, SCM, SCM-E) supposed properly models in WiBro RF (Radio Frequency) environment. Also we treat from basic theory to practical substance on the pathloss model to adopt WiBro network design/optimization. Finally, we describe about wireless network analysis tool named 'CellPLAN(R)' and techniques possible to improvethe accuracy of pathloss model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.2801-2808
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• 2010

The technology of WiBro, combining advantages of high speed internet and wireless internet provides the effectiveness and convenience provided by broadband and convergence. WiBro has developed due to supports of the related industries. The advancement of WiBro have created driving force for network advancement. WiBro is a niche market among high speed Internet, wireless LAN, Mobile phone, wireless internet. Through building relationship between market share and the existed telecommunication service, WiBro could improve the convenience of users. The security controls have to be built considering vulnerabilities of WiBro. Based on the study, the architecture of WiBro was suggested through reviewing the vulnerabilities and security controls in the wireless network and wire network. The appropriate security measures to be applied in the environment of WiBro. The outcomes of the study could improve the usage of WiBro.

• Journal of information and communication convergence engineering
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• v.8 no.3
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• pp.277-280
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• 2010

We report that broadcast messages in Mobile WiMAX networks should be synchronized throughout all the base stations to gain the benefit of beamforming technique. A simple synchronization implementation of broadcast messages in Mobile WiMAX networks is presented. Using this technique, the interference between broadcast messages and beamformed messages can be reduced.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.4
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• pp.820-822
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• 2010

Mobile WiMAX system provides various classes of traffic such as real-time and non-realtime services. These services have different QoS requirements and the QoS aware scheduling has been an important issue. Although many of scheduling algorithms for various services in OFDMA system have been proposed, it is needed to be modified to be applied to Mobile WiMAX system. Since Mobile WiMAX supports five kinds of service classes, it is important to take QoS characteristics of each class into consideration. In this paper, we propose an efficient packet scheduling algorithm to support QoS of each class. Proposed scheme selects a service class first considering QoS Characteristics of each class and choose an appropriate user in the selected class. Simulation results show that the proposed algorithm has better performance than the other algorithm.