• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7B
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• pp.660-667
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• 2006

Voice over Wireless LAN (VoWLAN) is defined as a communication service which transmits voice over wireless LAN. Due to its capability of providing high quality service while reducing communication costs, the VoWLAN is expected to be widely introduced to hospitals, hotels, and many more industry sectors. However, despite the increased interest in the new service, there has been limited research on the economic assessment of deploying VoWLAN. This paper provides a systematic and quantitative approach to the return on investment (ROI) analysis of VoWLAN service. We first analyze the domestic and international market trend of VoWLAN. Then, implementing scenarios of VoWLAN and corresponding alternatives are established. For each scenario, cost and benefit analysis is conducted. The proposed framework is implemented by using VBA program. To validate the result of the analysis, a case study is also conducted.

• Journal of Advanced Navigation Technology
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• v.10 no.2
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• pp.128-137
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• 2006

Recently, the combination of WLAN and 3G wireless technologies will make MMS service more ubiquitous, bringing benefits to both service providers and their customers. To realize seamless MMS service over WLAN and CDMA2000 networks, we design novel seamless interworking architecture by reusing the existing standards and network elements at the same time. Based on the proposed seamless interworking architecture, we also present seamless notification architecture and seamless handover architecture that can't be possible within current MMS reference architecture. This paper will make a contribution for service providers to provide their customers with seamless MMS service over WLAN and CDMA2000 networks.

• The KIPS Transactions:PartD
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• v.14D no.5
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• pp.565-572
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• 2007

In this paper, we developed a VoWLAN(Voice over WLAN) system based on an open source software. The system aims to provide VoIP service over wireless LAN with an IP-PBX server. The features of system presented in this paper are as follows. First, the initial cost for the development is reduced since the system is developed based on open source software. Second, the system provides various additional services such as Voice Mail, Conference Call, and Interactive Voice Response with a software IP-PBX server. Third, the VoWLAN terminal provides high-level user applications with minimal system resources using lightweight open software solutions. Finally, it is highly scalable since it is based on the open source software.

• Electronics and Telecommunications Trends
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• v.18 no.4 s.82
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• pp.1-10
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• 2003

최근 무선인터넷 및 WLAN 서비스 활성화와 함께 3G 이동통신망과 WLAN 망간의 서비스 연동 이슈가 주목을 받고 있다. WLAN 서비스는 높은 전송속도를 제공하는 반면에 서비스영역이 좁고, 3G(cdma2000 혹은 UMTS) 서비스는 서비스영역이 넓은 반면 데이터 전송속도가 낮고 요금 또한 고가이다. 본 고에서는 3G-WLAN 연동 고려사항 및 표준기술 동향을 살펴본다.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.208-210
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• 2009

Currently, Wireless LAN(WLAN) service is widely deployed to provide high speed wireless Internet access through the mobile stations such as notebook and PDA. To provide enhanced security and user access control in the public WLAN area, WLAN access points should have the capability of IEEE 802.1x-based user authentication and authorization functionality. In this paper, we provide a brief understanding of IEEE 802.1x standards and related protocols like EAPOL(Extended Authentication Protocol Over LAN), EAP, RADIUS and describe how the IEEE 802.1x is designed and implemented in our embedded linux-based WLAN AP which is named i-WiNG. (Intelligent Wireless Internet Gateway). For the network security and user authenti -cation purposes, a supplicant who wants to access Internet should be authorized to access the AP port using the EAPOL.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.4
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• pp.417-424
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• 2014

In this paper, a dual-band circular ring monopole antenna with semi-circular strip for WLAN(Wireless Local Area Networks)/WiMAX(World interoperability for Microwave Access) applications. The proposed antenna is based on a planar monopole design, and composed of half circular strip for dual-band operation which cover WLAN and WiMAX frequency bands. To obtain the optimized parameters, we used the simulator, Ansoft's High Frequency Structure Simulator(HFSS) and found the parameters that greatly effect antenna characteristics. Using the obtained parameters, the antenna is fabricated. The numerical and experiment results demonstrated that the proposed antenna satisfied the -10 dB impedance bandwidth requirement while simultaneously covering the WLAN and WiMAX bands. And characteristics of gain and radiation patterns are obtained for WLAN/WiMAX frequency bands.

• Journal of KIISE:Information Networking
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• v.37 no.2
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• pp.142-149
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• 2010

In this paper, we propose to modify the IEEE 802.16 MAC protocol in order to allow the coexistence of IEEE 802.11 and IEEE 802.16 wireless networks in shared bands. Our suggested protocol enables 802.16 WMAN to control WLAN devices for the coexistence. That is, in the downlink subframes(BS to SS), SS(Subscriber Station) prohibits WLAN to transmit by using CTS(Clear to Send) in order to protect it's burst. In the uplink subframes(SS to BS), on the other hand, BS(Base Station) sends CTS to block WLAN's communications. Our proposals enables the coexistence between WLAN and WMAN, and simulation results show that our protocols enhance the throughput of the entire system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.1
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• pp.81-92
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• 2009

Recently, there is a drastic increase in users interested in real-time multimedia services in the WLAN environment, as the demand of IEEE 802.11 WLAN-based services increases. However, the handoff delay based on 802.11i security policy is not acceptable for the seamless real-time multimedia services provided to MS frequently moving in the WLAN environment, and there is a possibility of DoS attacks against session key derivation process and handoff mechanism. In this paper, a secure and efficient handoff mechanism in the centralized WLAN environment is introduced to solve the security problems. The 4-way Handshake for both mutual authentication and session key derivation is replaced by the 2-way Reassociation process.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.1
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• pp.67-74
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• 2014

In this paper, we designed a multiband monopole antenna for next-generation WLAN system. In conventional WLAN system, UWB antennas were used together, and, because the radiation occurs in different parts depending on the antenna structure, it has the disadvantage of having an unstable impulse response characteristic due to dispersion characteristics. Although a UWB antenna that has suitable radiation pattern for WLAN band, it does not have good impedance matching and has severe echo. Therefore, in this paper, a monopole antenna was designed by using CPW power feed so that various impedances can be easily implemented when designing an antenna and more parameters can be derived that can be used for design for optimal performance.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.3
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• pp.533-538
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• 2018

For WLAN dual-band operation, a modified Yagi dipole antenna is presented. The modified dipole antenna consists of a dipole antenna with open sleeves and parasitic elements. The parasitic elements are used for the practical application of the radiation patterns and high-gain operation at the WLAN dual band. The experimental results showed that the achieved impedance bandwidths were 320 MHz (2.4 to 2.72 GHz) and 640 MHz (5.04 to 5.68 GHz), respectively. The measured maximum gain at the two WLAN bands was 7.74 dBi and 6.93 dBi, respectively.