• Journal of IKEEE
• /
• v.11 no.4
• /
• pp.227-234
• /
• 2007

In this paper, to support a QoS level appropriate to the user in Wireless Home Network based Wireless LAN, we propose a QoS support architecture which includes Wired Network and Wireless Network. Actually, an important problem to support QoS in Wireless Home Network is approached not only on a MAC level in Wireless LAN but also on a integrated method to combine Network layer with Datalink layer. By applying the integrated QoS support method, it is possible to provide QoS support architecture using a Wireless LAN terminal with a minimum changing, and the proposed scheme has advantage of QoS support method, which is more superior than a existing scheme to support QoS in MAC level of Wireless LAN. Simulations results show that overall performance of the proposed scheme can be improved.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.11
• /
• pp.4405-4418
• /
• 2015

Different network provides different service. To maximize the profit, heterogeneous networks form a whole, which may either compete or cooperate with each other. In this paper, the healthcare monitor network architecture is introduced to build the competitive and cooperative mechanisms of heterogeneous networks which contain three networks, namely, cellular network, WLAN and WMAN. This paper considers the natural growth rate of the network with competitive and cooperative effects. Then, the stability of the proposed model and its equilibrium points are analyzed by the ordinary differential principle. Finally, simulation results show that the natural growth rate cannot increase the profit of the network, but effective cooperative among heterogeneous networks can increase the profit of each network, and competitive may decrease the profit of each network.

• Proceedings of the IEEK Conference
• /
• 2002.07a
• /
• pp.549-551
• /
• 2002

A Wireless Local Area Network (WLAN) is a flexible data communication system implemented as an extension to, or as an alternative for, a wired LAN with in a building or campus. However, communications in an indoor environment present problems not encountered in outdoor wireless communication systems. Since cellular type systems are interference limited, the indoor environment is more hostile than the outdoor environment due to the lower propagation constant. In this paper, the equation for the signal to interference ratio in a multistory building will be derived. Knowing the S/I ratio, the floor frequency reuse can be determined. Finally, the simulation in this research is designed to study the performance (BER) of WLAN system in the multistory environment by applying the 8-PSK Trellis Coded modulation technique. The procedure allows a quick evaluation of BER in Wireless LAN system due to the co-channel interference.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.2 s.344
• /
• pp.1-6
• /
• 2006

This paper proposes association algorithm using load balancing for efficient AP selection under environment of wireless local area network(WLAN). Our scheme measures arrival time of association information when establishing the connection between access points and access terminal, analyzes the load condition of AP, and applies load balancing. AT selects and sets up low traffic AP by measuring traffic of connected access terminal, which can prevent over-franc of access points under hotspot environment that users access simultaneously. According to the above-described selection in a high speed wireless Internet service based on public WLAN technologies that are currently in operations. Further, it is possible to improve the efficiency of network management.

• Journal of electromagnetic engineering and science
• /
• v.10 no.3
• /
• pp.92-98
• /
• 2010

A new wideband bandstop filter(BSF) with a sharp roll-off characteristic is introduced in a stripline structure in this paper. The BSF consists of two sections: the first is two capacitively coupled $\lambda/4$ short-circuited lines with opposite ground positions, while the second is a capacitively coupled $\lambda/4$ short-circuited line. The BSF provides three transmission zeros within the stopband and better than 22 dB rejection over the whole wireless local area network (WLAN) band from 5.15 to 5.825 GHz. The BSF, cascaded to an U.S. ultra-wideband(UWB: 3.1~10.6 GHz) band-pass filter(BPF), is simulated with HFSS and realized with low-temperature co-fired ceramic(LTCC) green tape with a dielectric constant of 7.8. The measurement results agree well with the HFSS simulation results. The size of the UWB BPF including the BSF is $3{\times}6.3\times0.45\;mm^3$.

• Journal of Internet Computing and Services
• /
• v.11 no.3
• /
• pp.33-41
• /
• 2010

The battery consumption and the wireless communication pattern were analyzed for the low power and the improvement of channel interferences between of Zigbee networks and WPAN(Wireless Personal Area Network). The communication patterns considering end device's battery saving during channel searching period were analyzed for low power consumption topology of Zigbee dynamic ad-hoc characteristics. And, the communication patterns were analyzed due to channel interferences between WLAN and Random Back off of Zigbee, too. As a result, the communication patterns of Zigbee's coordinator and end devices is alleviated for the longer battery life time of Zigbee's end device due to Zigbee's end device setting techniques.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
• /
• 2006.06a
• /
• pp.501-505
• /
• 2006

다양하게 제공되고 있는 무선 네트워크 서비스를 통합하기 위한 보안 연동 기술 개발이 활발히 이루어지고 있다. 통합 보안 연동 기술을 위해 IETF에서 EAP-AKA(Extensible Authentication Protocol-Authentication and Key Agreement)[8]가 표준으로 제안되었지만 HN(Home Network)이 MS(Mobile Station)를 직접 인증하지 못하고 사용자의 permanent identity가 노출되는 등 여러 보안상의 문제점이 제기되고 있다. 또한 SN(Serving Network)이 필요로 하는 저장 공간이 너무 많고 SN과 HN 사이의 대역폭 낭비, 동기화 문제 등 효율성에 있어서도 문제점이 제기되고 있다. 이 논문에서는 개선한 AKA(Authentication and Key Agreement)[12] 프로토콜을 PEAP(Protected EAP)에 적용하여 기존 EAP-AKA보다 안전하고 효율적인 티켓기반의 프로토콜을 제안한다. 제안하는 프로토콜은 HN과 MS 간의 상호 인증을 보장하고 사용자의 permanent identity를 보호하여 안전하고, 계산량과 저장 공간에 있어 기존의 EAP-AKA보다 효율적이다.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.10 no.5
• /
• pp.60-70
• /
• 2011

Vehicle location detection and wireless communication method have be designed along the same lines as GPS, CDMA and WLAN, which is based upon the selecting factors such as state-of-art technology trend, accuracy, stability, and economic feasibility, in order to select the optimum method of information communication networks for integrated "Transportation-Power-Facilities" on the electric bus. In addition, the key features of each alternative for an efficient linkage have been review and the integration methodology for linking among Transportation Charging Center, Transportation(ITS, BIS) Center and smart Grid Center has been drawn up based on a technical level of difficulty of each alternative, political and administrative difficulties, and expense justification.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.10a
• /
• pp.685-687
• /
• 2013

Today, as wireless communications devices such as laptops, smart phones are generalized, wireless LAN has been widely installed in the corporate office conference rooms, industrial warehouses, Internet-ready classrooms, and even in a coffee shop. Though a wired network can be accessed and attacked only by the physical penetration, the wireless network which can be accessed anywhere within the reach of anyone has relative vulnerability by unauthorized users' attack. To defend these vulnerabilities, the introduction of WIDS / WIPS is required. In this paper, we recognize the limitations of WLAN security technology, review the current technology trends and propose the solutions in the future security problems.

• Journal of Communications and Networks
• /
• v.13 no.2
• /
• pp.149-159
• /
• 2011

In this paper, we study the problem of how to design a medical-grade wireless local area network (WLAN) for healthcare facilities. First, unlike the IEEE 802.11e MAC, which categorizes traffic primarily by their delay constraints, we prioritize medical applications according to their medical urgency. Second, we propose a mechanism that can guarantee absolute priority to each traffic category, which is critical for medical-grade quality of service (QoS), while the conventional 802.11e MAC only provides relative priority to each traffic category. Based on absolute priority, we focus on the performance of real-time patient monitoring applications, and derive the optimal contention window size that can significantly improve the throughput performance. Finally, for proper performance evaluation from a medical viewpoint, we introduce the weighted diagnostic distortion (WDD) as a medical QoS metric to effectively measure the medical diagnosability by extracting the main diagnostic features of medical signal. Our simulation result shows that the proposed mechanism, together with medical categorization using absolute priority, can significantly improve the medical-grade QoS performance over the conventional IEEE 802.11e MAC.