• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.53-63
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• 2009

This paper is to develop WiMAX CPE(wireless AP) that can provides Wi-Fi terminal with wireless Internet service by connecting to Wibro wireless network. This AP aims to support WiBro in upstream interface basically, and Wi-Fi and 100M Ethernet interface in downstream. So, we has developed the equipment for business that wireless ISP can provide many Internet customers with wireless Internet service by using Wi-Fi terminal in subway, car, ship, and so on, and the equipment for users that a user can purchase and then install in person. For the latter, multiple Wi-Fi terminals that be registered in WiBro service can be connected to Internet simultaneously.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.59-64
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• 2014

This paper address the scheme for WiMAX backhaul in mobile communication network. These days most ISPs has implemented Wi-Fi backhaul using T1/E1 and DSL. if WiMAX is installed as the alternative to the mobile backhaul, it can decrease the costs drastically for the installation and operations. And it will be one of the best cost-effective solutions to cover the service areas which has not the wired communication infrastructure. WiMAX can be used for Base station, Subscriber Station, and Relay. In this paper, the performance is measured for downstream and upstream using NAT and port forwarding functions by configuring WiMAX server and WiMAX SS.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.5
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• pp.167-172
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• 2010

This paper is to implement HSDPA-CPE that can provides WiFi terminal with wireless Internet service through the connection to HSDPA wireless network. This system aims to support HSDPA interface in upstream, and WiFi and 100Mbps Ethernet interface in downstream. So, this system can provide multiple Internet customers with wireless Internet service by using WiFi terminal in subway, car, ship, and so on, and WiFi terminals that be registered in HSDPA service can be connected to Internet.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11B
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• pp.1357-1362
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• 2011

TV White Spaces (TVWS) are freed up after transition from analog television to Digital Television (DTV). Some wireless communications are allowable to operate in TVWSs, such unlicensed Wireless Fidelity (WiFi). Because TVWSs are located in the VHF and UHF bands, TVWSs can provide significantly better coverage and wall penetration inside buildings and other structures than the 2.4 GHz and 5 GHz WiFi frequencies currently in use. Therefore, this paper assumes that WiFi will be deployed in TVWSs. However, the interference impact of WiFi on DTV has to be taken into account. The interference probability in DTV receiver was evaluated by using Spectrum Engineering Advanced Monte-Carlo Analysis Tool (SEAMCAT). As a result, when 20 WiFi UEs are simultaneously operating at the maximum transmit power of 23 dBm and the guard band is 22 MHz, the protection distance should be at least 6 km to meet the interference probability of 5% in DTV receiver.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.3
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• pp.906-918
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• 2012

Wireless Fidelity (WiFi) and Wireless microphone are assumed to operate on adjacent channels in TV White Spaces(TVWS). The Scenario of WiFi potentially interfering with Wireless microphone is analyzed through Minimum Coupling Loss (MCL) and Spectrum Engineering Advanced Monte Carlo Analysis Tool (SEAMCAT) based on the Monte-Carlo simulation method. In the case of single WiFi interfering with Wireless microphone, the protection distance between WiFi and the Wireless microphone should be at least 25.12 m to avoid WiFi impact on Wireless microphone. When the active number of WiFi is 12, the guard band between WiFi and Wireless microphone should not be less than 4.97 MHz to guarantee that WiFi does not interfere with the Wireless microphone.

• The Journal of the Korea Contents Association
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• v.11 no.1
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• pp.34-41
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• 2011

At present wireless internet access service is available through the 3G network, mobile WiMAX and WiFi anytime and anywhere. In this environment where there are various networks, users should be able to select specific networks depending on different situations. And it is necessary to provide mobility support between homogeneous and between heterogenous networks. Given this situation, the many proposals have been presented to link 3G, which has the largest service area among various networks, with mobile WiMAX(IEEE 802.16e), or with WiFi(IEEE 802.11). But, recently, with the increasing volume of wireless internet use and wireless internet data, due to the advents of net-book, e-book and smart phone, the service area of WiFi and mobile WiMAX has rapidly expanded. Especially, the availability of real-time application such as internet phone has led to the relative shrinking of the proportion of 3G mobile communication network giving conventional voice service, and enlargement of those of wireless internet access networks like WiFi and mobile WiMAX. This paper suggests a handover scheme based on PMIPv6, whitch support mobility between WiFi and mobile WiMAX, and minimizes handover delay. In this scheme, the mobile node has a dual stack structure composed of two interfaces-WiFi and mobile WiMAX. Since WiFi dose not support mobility, it is suggested that the mobile node have the capacity to deal with handover signaling between gateway in case of handover between homogeneous networks. This handover scheme, suggested comparing with current handovers between homogeneous networks, has proved, in its analytic evaluation, to be able to reduce handover, transmission, and signaling overhead.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.649-652
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• 2007

In the world each bureau tries an introduction of Mobile WiMAX frequency in the various band. Particularly, 2.5 GHz band is likely to be used as the future mobile telecommunication using as the IMT-2000 additional band which determined in WRC, and it comes into the spotlight as the band of the global radio broadband service including the Mobile WiMAX. Thus, the activity for including the Mobile WiMAX to the IMT-2000 technical standard is unfolded for the WiBro market development in the ITU-R WP8F conference, and the adoption or rejection will be finally determined in the ITU-R RA-07. Therefore, this paper tried to look for the plan for reaction according to the IMT-2000 standard acceptance of WiBro technology and the foreign usage plan of 2.5 GHZ band.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.251-256
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• 2011

In this paper, we analyze the distance between two systems, WiBro and WLAN, compared to standard interference probability for channel co-use in order to be used as a criteria in realization. Co-channel and adjacent channel interference probability and its effect of (WiBro) into Wireless LAN (WLAN) in TV White Spaces (TVWS) is evaluated through Spectrum Engineering Advanced Monte Carlo Analysis Tool(SEAMCAT) based on the Monte-Carlo simulation method. As a result, in the case of co-channel interference, the minimum distance between WiBro Mobile Station(MS) and WLAN User Equipment (UE) should be 210 m to allow the maximum transmitter power of WiBro UE of 25 dBm. The transmit power of WiBro BS have to be reduced to -4.96 dBm.

• Journal of Digital Contents Society
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• v.14 no.4
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• pp.471-479
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• 2013

WiBro technology provide mobile devices with a transmission speed of more than 1 Mbps even under the condition of high mobility (120 km/h). In a building, however, there is more demand for high bandwidth for various activities, and WiBro services may not be available. In order to guaranteeing a seamless service continuity and high transmission capability for mobile users within a specific establishment that has deployed WiBro network, we should secure an internetworking platform for WiBro and WiFi networks. This paper introduces WiMax forum and 3GPP standards, proposes WiBro-WiFi Interworking (WWI) architecture, its implementation details, and finally verifies validity of the proposal by using OPNet simulations.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.456-457
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• 2021

Recently, in order to more accurately provide indoor location-based services, technologies using Wi-Fi fingerprints and deep learning are being studied. Among the deep learning models, an RNN model that can store information from the past can store continuous movements in indoor positioning, thereby reducing positioning errors. When using an RNN model for indoor positioning, the collected training data must be continuous sequential data. However, the Wi-Fi fingerprint data collected to determine specific location information cannot be used as training data for an RNN model because only RSSI for a specific location is recorded. This paper proposes a region clustering technique for sequential input data generation of RNN models based on Wi-Fi fingerprint data.