• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.17 no.2
• /
• pp.41-49
• /
• 2007

USIM(UMTS Subscriber Identity Module) technology that accept 3GPP(3rd Generation Partnership Project) standards for information security supports security function in 3GPP. Supported security functions of USIM are confidentiality of user identity, mutual authentication and key agreement between end user and network, confidentiality of user data and data integrity. It is very important technology in wireless network. It makes secure environment that user and service provider can use securely mobile service in network. In this paper, design and implementation USIM security module that supports common network access method and authentication protocol in 3GPP and WLAN(Wireless LAN) and AAA (3A-Authentication Authorization Accounting) server system based RADIUS.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.23 no.8
• /
• pp.900-908
• /
• 2012

Owing to the proliferation of smart phone users, a proactive spectrum policy is needed in order to deal with increasing data traffic. Therefore, the prediction of frequency requirements for future wireless local area network (WLAN) as well as a licensed cellular communication is necessary. In this paper, we proposed a new prediction method for WLAN spectrum requirements. This method includes both a traditional prediction method and an offloading percentage from cellular network, Also, it can consider a frequency interference between access points using a statistical approach. Based on these approaches, we can predict the spectrum requirements of future domestic WLAN services considering the frequency interference. Finally, we suggest the spectrum policy for WLAN which can prevent spectrum shortage of future WLAN services.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.19 no.1
• /
• pp.81-92
• /
• 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 Korean Institute of Communications and Information Sciences
• /
• v.42 no.5
• /
• pp.1102-1109
• /
• 2017

In Train Control Network(TCN), to support advanced services beyond control applications, it was revised to support high speed ethernet as IEC 61375-2-5(ETB) and IEC 61375-3-4(ECN). And Train Topology Discovery Protocol(TTDP) was included by which train-consist can be automatically configured. Meanwhile, to adopt wireless LAN as an next onboard network, TTDP need to be modified to reflect the characteristics of WLAN. This paper proposed a TTDP for WLAN using transmission power control and the number of HELLO-ACK handshake. And it determined whether the TTDP executed using the two WLAN interfaces having different bandwidths is correct or not. The proposed TTDP can allow to reduce interference from other nodes. For evaluation of performance of TTDP, NS-2 was used. The evaluation result shows the high reliability of the TTDP in wireless environment.

• IE interfaces
• /
• v.16 no.2
• /
• pp.195-200
• /
• 2003

In this paper, the selective use of RTS and CTS frames is considered to analyze the capacity of IEEE 802.11 WLAN (Wireless Local Area Network). The RTS and CTS frames are used to transmit the data frames longer than dot11RTSThreshold according to IEEE 802.11 specification. The analysis of the optimal RTS-CTS threshold is derived to maximize the capacity of IEEE 802.11 WLAN. And, numerical examples are also presented for IEEE 802.11 a and b WLANs.

• Proceedings of the IEEK Conference
• /
• 1999.06a
• /
• pp.45-48
• /
• 1999

The demands of WLAN(Wireless Local Area Network) systems increase rapidly in whole society and this phenonenon has been expected that WLAN wi11 substitute for wired-LAN. The FHSS(Frequency Hopped Spread Spectrum) method using the WLAN is changed to the performance of Frequency synthesizer. In this paper, we proposed pipeline-accumulator using ring-counter method instead of constant accumulator that has demerits of size and power consumption. Designed DDFS generated operating frequency of 167MHz and maximum output frequency of 83.5MHz.

• Proceedings of the IEEK Conference
• /
• 2003.11c
• /
• pp.187-190
• /
• 2003

최근 IEEE에서 WLAN을 표준으로 하는 802.11g가 확정되면서 이를 지원하는 AP가 출시되었다. AP에서 사용되는 OS는 POSIX를 기반으로 된 Linux 같은 OS를 통하여 구현되고 있 다. 이 논문에서는 가장 범용으로 사용되고 있는 Rad Hat을 기반으로 한 embeded linux를 만들어본다. 이와 함께 embeded linux를 가지고서 Network 기능을 추가하고, AP 하드웨어 드라이버 및 AP 모듈을 올려서 구연한다. 여기에 추가적으로 DHCP나 Web UI기능 등의 부가 기능을 추가하여 AP를 구현하는데 목적이 있다.

• Proceedings of the IEEK Conference
• /
• 2007.07a
• /
• pp.189-190
• /
• 2007

We propose an efficient internetworking model for fast handover between UMTS and WLAN networks. Mobility anchor (MA) is provided at the boundary between GGSN and PDG, under the 3GPP-proposed internetworking reference model. Such MA can enable authentication and session initialization before L2 handover of the mobile terminal, so that seamless and fast vertical handover could be possible.

• Proceedings of the Korean Information Science Society Conference
• /
• 2003.10c
• /
• pp.133-135
• /
• 2003

본 논문에서는 IEEE 802.11 WLAN $^{[1]}$ 에서 QoS를 제공하기 위해 새로운 MAC­layer 구조를 제안한다. 주요 특징으로는 향후 Core Network의 모델로서 제시되고 있는 DiffServ 구조의 특징들을 WLAN에 적용하는 것을 들 수 있으며, 이를 통해 다양한 종류의 멀티미디어 트래픽에 적용될 End­to­end QoS를 보다 효율적 보장하고자 한다. DiffServ에서 제시되고 있는 Expedited. Assured forwarding과 일반적인 Best­effort traffic에 대한 service 차등화 기법을 WLAN에서 적용하기 위해 기존 MAC layer에서의 DCF, PCF 대신 EDWM(Extended DiffServ in WLAN MAC)이라는 새로운 MAC­layer 구조를 제시한다. 이를 통해 시간지연에 민감한 Expedited forwarding과 대역폭의 보장을 필요로 하는 Assured forwarding의 요구 사항(QoS)을 효율적으로 보장할 수 있다. 이에 더하여 기존의 인프라(infrastructure)인 IEEE 802.11b 환경의 DCF와 이를 통하여 service를 제공받는 일반적인 Best­effort traffic을 위한 backward compatibility 보장 방안을 제시한다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.12B
• /
• pp.1039-1049
• /
• 2008

Multihoming is an attractive feature for mobile nodes (MN) equipped with multiple network interfaces in a converged networking environment. However, the current standard Mobile IP (MIP) lacks support for multihomed MNs. Accordingly, this paper presents an immediate solution to resolve the problems of multihomed MNs in a UMTS and WLAN interworking system. The interworking system is based on a hierarchical architecture according to the UMTS and WLAN coverage characteristics. The MIP is only operated in the WLANs, and not in the UMTS, allowing the MIP to be used for multihomed MNs with minimal modifications. In addition, MIP binding filters are used to realize the advantages of multihoming, enabling different traffic flows to be transmitted simultaneously through different interfaces. The overall design aims to minimize the modification to the MIP and impact on existing UMTS and WLAN systems. We evaluate the performance of proposed scheme using an OPNET simulator.