• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37C no.9
• /
• pp.821-828
• /
• 2012

Recently, in order to provide the mobile multimedia service cost-effectively, the user's demand has been greatly increasing to use wireless LAN (WLAN). But existing WLAN (Wireless LAN) is vulnerable to attack of outside, as users are connecting AP using Open Authentication. In this article, we have designed and implemented WLAN Information Sharing System using social network service (SNS) which is efficiently managing. WLAN secure key. A proposed WLAN Information Sharing System model has been proposed in which the social trust strength between people is employed for WLAN access control.

• Journal of KIISE
• /
• v.42 no.10
• /
• pp.1254-1267
• /
• 2015

Recently, excessive installations of APs have caused WLAN interference, and many techniques have been suggested to solve this problem. The AP aggregation technique serves to reduce active APs by moving station connections to a certain AP. Since this technique forcibly moves station connections, the transmission performance of some stations may deteriorate. The AP transmit power control technique may cause station disconnection or deterioration of transmission performance when power is reduced under a certain level. The combination of these two techniques can reduce interference through AP aggregation and narrow the range of interferences further through detailed power adjustment. However, simply combining these techniques may decrease the probability of power adjustment after aggregation and increase station disconnections upon power control. As a result, improvement in performance may be insignificant. Hence, this study suggests a scheme to combine the AP aggregation and the AP transmit power control techniques in OpenFlow-based WLAN to ameliorate the disadvantages of each technique and to reduce interferences efficiently by performing aggregation for the purpose of increasing the probability of adjusting transmission power. Simulations reveal that the average transmission delay of the suggested scheme is reduced by as much as 12.8% compared to the aggregation scheme and by as much as 18.1% compared to the power control scheme. The packet loss rate due to interference is reduced by as much as 24.9% compared to the aggregation scheme and by as much as 46.7% compared to the power control scheme. In addition, the aggregation scheme and the power control scheme decrease the throughput of several stations as a side effect, but our scheme increases the total data throughput without decreasing the throughput of each station.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.3
• /
• pp.441-450
• /
• 2015

Nowadays, many WLAN access points (APs) are deployed in hotspot areas such as shopping malls and stations. As the number of WLAN APs deployed increases, how to manage densely deployed APs in an efficient manner becomes one of the most important issues in WLANs. In this environment, uncoordinated multicast services can lead to frequent collisions due to simultaneous transmissions among APs. In this paper, we propose a multicast scheduling algorithm that can exploit simultaneous transmissions in multiple sectors and avoid redundant transmissions in dense networks. Simulation results demonstrate that the proposed scheme can reduce the multicast transmission latency compared to comparison scheduling schemes.

• Review of KIISC
• /
• v.15 no.5
• /
• pp.83-89
• /
• 2005

네트워크 컨버전스 및 사용자 이동성의 중시로 무선랜 기반에서 음성 서비스를 이용하고자 하는 VoWLAN 서비스에 대한 관심이 고조되고 있다. 그러나 무선랜 보안 표준기술을 그대로 적용하고자 할 때는 AP 간을 이동할 때와 서브넷 간을 이동할 때 로밍에 대한 문제가 발생한다. 이에 본 논문에서는 VoWLAN 서비스를 구현할 때 로밍과 보안 기능을 동시에 제공하기 위한 설계방법을 제안한다.

• Journal of Digital Contents Society
• /
• v.19 no.8
• /
• pp.1545-1554
• /
• 2018

In order to support the mobility of the wireless devices, at least two APs (Access Points) must be arranged in a single AP area to maintain communication area. In the WLAN (Wireless LAN) environment, seamless handover is one of the most important issues in terms of effective utilization of wireless networks and maximization of services for users. On the other hand, SDN (Software-Defined Networking), which is emerging rapidly in recent years, is revolutionizing network management in terms of flexibility, fine control, and convenience. SDN originally reduces latency time or increases network robustness by real-time flow table control reducing or bypassing paths between switches in LAN-based data centers. In this study, we apply OpenFlow, a SDN platform focused on wired LAN, to a dense WLAN environment using legacy APs to implement and evaluate seamless handover for streaming services of digital contents.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.3
• /
• pp.997-1005
• /
• 2010

Recently, there has been a growing interest in the use of WLAN technology due to its easy deployment, flexibility and so on. Examples of WLAN applications range from standard internet services such as Web access to real-time services with strict latency/throughput requirements such as multimedia video and voice over IP on wireless network environments. Fair and efficient distribution of the traffic loads among APs(Access Points) has become an important issue for improved utilization of WLAN. This paper focuses on an AP selection scheme for achieving better load balance, and hence increasing network resource utilization for each user on wireless network environments. This scheme makes use of active scan patterns and the network delay as main parameters of load measurement and AP selection. This scheme attempts to estimate the AP traffic loads by observing the up/down delay and utilize the results to maximize the link resource efficiency through load balancing. We compared the proposed scheme with the original SNR(Signal to Noise Ratio)-based scheme using the NS-2(Network Simulation.2). We found that the proposed scheme improves the throughput by 12.5% and lower the network up/down link delay by 36.84% and 60.42%, respectively. All in all, the new scheme can significantly increase overall network throughput and reduce up/down delay while providing excellent quality for voice and video services.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.5
• /
• pp.1146-1151
• /
• 2007

In this paper, it is investigated to the security services and vulnerability tools of IEEE802.11 wireless LAN, and it is considered the employment state of wireless LAN AP (access point) and analyzed the state of security vulnerability. In according to this study, among wireless LAN APs, which are operated in each company or each factory, in center around industrial of Cheonan city, 50% of AP, which is used, is not operated on WEP, and therefore, it is stated the weakness of security so far. From the result of this study, in case of mid and small company, it can be distinguished the necessity of the security training for the informaton system manager.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.11 s.353
• /
• pp.159-167
• /
• 2006

IEEE 802.11i standard specifies full authentication and preauthentication for secure handoff in 802.11 wireless LAN (WLAN). However, the full authentication is too slow to provide seamless services for handoff users, and preauthentication may fail in highly populated WLAN where it is highly probable that the cache entry of a preauthenticated user is evicted by other users before handoff. In this paper, we propose a fast and secure handoff scheme by reducing authentication and key management delay in the handoff process. When a user handoffs, security context established between the user and the previous access point (AP) is forwarded from the previous AP to the current AP, and the session key is reused before the handoff session terminates. The freshness of session key is maintained by regenerating session keys after handoff session is terminated. The proposed scheme can achieve considerable reduction in handoff delay with providing the same security level as 802.1X authentication by letting an AP authenticate a handoff user before making an robust security network association (RSNA) with it.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.12
• /
• pp.2195-2200
• /
• 2008

The use of WLAN technology specially 802.11 b and g has seen huge subscriber growth in a relatively short time period due to low cost and ease of installation of WLAN hardware. These technologies provide multiple data rates ranging from 1 to 54 Mbps depending on modulation used in physical layer. This paper presents the performance of 802.11b and g under different data rates in mobile IPv4 environment. OPNET is used in the study as the network simulator. The performance metrics used in this wort is data traffic received by a WLAN station roaming amongst Access Point(AP) of different ESSs. It is found that much data packets are lost during handover between mobile agents. The traffic received by the roaming station varies based on the data rates provided by two different WLAN technologies.