• Journal of Korea Society of Industrial Information Systems
• /
• v.11 no.4
• /
• pp.32-39
• /
• 2006

MANET is a dynamically reconfigurable wireless network with no fixed infrastructure (base station, or AP). In order to provide the data service in MANET, we need an efficient routing protocol to deliver the data to the wanted destination at a mobile node. A method of routing protocols called reactive routing protocol has recently got attention because of their low routing overhead. But a method of flooding broadcasts the packet to all of its neighbors. For this reason, each of the node has high routing overhead to route and keep path discovery. Accordingly in this paper, I propose an adaptive flooding scheme using N-hop look-ahead in MANET, md an optimal N value of doing flooding the packet to limited area. Because of being basically ignorant about topological changes, each of the node did not spontaneously cope with path alteration. But an efficient flooding scheme applying N-hop look-ahead is more resilient to topology changes than traditional algorithms. And also with this efficient flooding scheme, the simulation results demonstrate excellent reduction of routing overhead.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.6B
• /
• pp.495-507
• /
• 2006

In wireless local area networks (WLANs), the successful design of scheduling algorithm is a key factor in guaranteeing the various quality of service (QoS) requirements for the stringent real-time constraints of multimedia services. In this paper we propose a multipolling-based dynamic scheduling algorithm for providing delay guarantees to multimedia traffics such as MPEG streams. The dynamic algorithm exploits the characteristics of MPEG stream, and uses mini frames for feedback control in order to deliver dynamic parameters for channel requests from stations to the point coordinator (PC) operating at the access point (AP). In this scheme, the duration of channel time allocated to a station during a superframe is changed dynamically depending on the MPEG frame type, traffic load and delay bound of the frame, etc. Performance of the proposed scheme is investigated by simulation. Our results show that compared to conventional scheme, the proposed scheme is very effective and has high performance while guaranteeing the delay bound.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.3B
• /
• pp.398-407
• /
• 2010

Due to increase of user requirement for various traffics and the advance of network technology, each distinct network has converge into FMC(Fixed Mobile Convergence) networks. However, we need to research the performance analysis of VoIP(Voice over Internet Protocol) in the FMC network to provide QoE for the voice user of FMC network. Therefore, this paper introduces the scenario which is the situation of voice quality degradation when a user uses VoIP to communicate with other users in the FMC network. Especially, this paper presents scenario in terms of the component of the network and finds the improvement point of voice quality. In the simulation results, three improvement points of voice quality are found as following: voice quality degradation by packet loss in the physical layer of the HSDPA network, by utilizing GGSN without QoS parameter mapping mechanism which is gateway between 3GPP and IP backbone, and by using non-QoS AP in the WLAN network.

• The Journal of the Convergence on Culture Technology
• /
• v.6 no.1
• /
• pp.455-461
• /
• 2020

Electronic payment system using Internet banking is a very important application for users of e-commerce environment. With rapidly growing use of fintech applications, the risk and damage caused by malicious hacking or identity theft are getting significant. To prevent the damage, fraud detection system (FDS) calculates the risk of the electronic payment transactions using user profiles including types of goods, device status, user location, and so on. In this paper, we propose a new risk calculation method using relative location of users such as SSID of wireless LAN AP and MAC address. Those relative location information are more difficult to imitate or copy compared with conventional physical location information like nation, GPS coordinates, or IP address. The new method using relative location and cumulative user characteristics will enable stronger risk calculation function to FDS and thus give enhanced security to electronic payment systems.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.24 no.7
• /
• pp.898-903
• /
• 2020

In this paper, we propose an indoor logistic tracking system that identifies the location and inventory of the logistics in the room based on fingerprints. Through this, we constructed the actual infrastructure of the logistics center and designed and implemented the logistics management system. The proposed system collects the signal strength through the location terminal and generates the signal map to locate the goods. The location terminal is composed of a UHF RFID reader and a wireless LAN card, reads the peripheral RFID signal and the signal of the wireless AP, and transmits it to the web server. The web server processes the signal received from the location terminal and stores it in the database, and the user uses the data to produce the signal map. The proposed system combines UHF RFID with existing fingerprinting method to improve performance in the environment of querying multiple objects.

• KIPS Transactions on Computer and Communication Systems
• /
• v.12 no.6
• /
• pp.197-208
• /
• 2023

In the coming future, anyone using the Internet will have more than one NFT. Unlike FT, NFT can specify the owner, and tracking management is easier than FT. Even in the 2022 survey, WPA2 is the most widely used wireless protocol worldwide to date. As it is a protocol that came out in 2006, it is a protocol with various vulnerabilities at this time. In order to use WPA2-EAP or WPA3 (2018), which were released to compensate for the vulnerabilities of WPA2, additional equipment upgrades are required for STA (station) and AP (access point, router), which are connected devices. The use of expensive router equipment solves the security part, but it is economically inefficient to be introduced in Small Office Home Office (SOHO). This paper uses NFT as a means of authentication and uses the existing WPA2 as it is without equipment upgrade, defend crack tools of WPA2 that have been widely used so far and compared to the existing WPA2, it was shown that it was not difficult to actually use them in SOHO.

• Journal of Advanced Navigation Technology
• /
• v.6 no.1
• /
• pp.37-43
• /
• 2002

This paper describes the performance evaluation and analysis of Wireless Local Area Network (W-LAN) in the 5 GHz ISM-band in compliance with IEEE 802.11a. At present, most W-LAN products are based on 2.4 GHz band, but low speed (11Mbps) has the limitation to serve systems demanding high-speed data transmission. To solve this problem, it is necessary to design next generation W-LAN system with 54Mbps in the 5GHz. It is sure that implementation of next generation W-LAN will bring competitive advantages. In particular, it will support telecommunications for high-speed mobile environments as well as for fixed places such as a school zone, a lecture room, a hospital and other premises. A few simulation methods are applied to more accurate and reliable performance analysis of next generation W-LAN. To verify if continuous data service is supported for a high-speed mobile notebook, multi-path fading channels between wireless Access Point (AP) and wireless Network Interface Card (NIC) are modeled. In addition, low interference is analyzed via convolutional codes and Orthogonal Frequency-Division Multiplexing (OFDM). Also, to obtain reliable Bit Error Rate (BER), a single tap Least Mean Square (LMS) equalizer is applied. Given the above simulation, next generation W-LAN is an ideal solution for continuous data transmission in high-speed mobile environments.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.8 no.3
• /
• pp.81-86
• /
• 2008

The paradigm of information & communication is rapidly changed into ubiquitous environment based electromagnetic wave, and antenna technology in the wireless ubiquitous communication is remarkably developed. Mini chip antenna has its within small card compared to the external AP antenna. Designed and Fabricated WLAN antenna has a broadband characteristics of 2.4~2.5GHz and 4.9~5.85GHz, and can be used triple mode of IEEE 802.11.a,g.b, and it has comparatively a constant performance in the dual frequency band.

• Journal of Advanced Navigation Technology
• /
• v.12 no.3
• /
• pp.239-244
• /
• 2008

In this paper refer to the digital multimedia mobile phone with the combination of broadcasting and the communication the unity of wire and wireless solution that can provide the UMA(Unlicensed Mobile Access) function is added. In UNC(Universal Naming Convention) in the case of CAS(Conditional Access System) is supported, the device(mobile phone) is authenticated through AP and then following the method of broadcasting signal the user can view the wanted contents as long as they want and for this matter the service charge system are proposed.

• KIISE Transactions on Computing Practices
• /
• v.23 no.4
• /
• pp.210-216
• /
• 2017

In the paper we propose and implement a new indoor localization system where the techniques of magnetic field based fingerprinting and pedestrian dead reckoning are combined. First, we determine a target's location by comparing acquired magnetic field values with a magnetic field map containing pre-collected field values at different locations and choosing the location having the closest value. As the target moves, we use pedestrian dead reckoning to estimate the expected moving path, reducing the maximum positioning error of the initial location. The system eliminates the problem of localization error accumulation in pedestrian dead reckoning with the help of the fingerprinting and does not require Wi-Fi AP infrastructure, enabling cost-effective localization solution.