• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.5B
• /
• pp.243-252
• /
• 2008

In this paper, we propose the next-generation broadband wireless access network architecture, which is based on the wavelength division multiplexing-passive optical network(WDM-PON), and efficient mobility management scheme to support quality-of-service(QoS) of multimedia services in the next-generation wireless network. By adapting WDM-PON technology to wireless access network, the proposed scheme can realize broadband wireless access network. In addition, We utilize newly proposed local channels between optical network units(ONUs) or subnets in order to support the fast and efficient local data and handoff data transmission. We evaluate the performance of the proposed scheme in terms of handoff delay and packet loss thru computer simulation. Thru various computer simulation results, we verified the superior performance of the proposed scheme by comparing with the results of other schemes.

• 한국정보통신설비학회:학술대회논문집
• /
• 2006.08a
• /
• pp.91-94
• /
• 2006

In this paper, we deployed the tunnel inspection and monitoring system by wireless sensor network. It is shown that the wireless sensor network which is composed of sensor, wireless communication module, and gateway system can be applied to tunnel monitoring system. Sensors included herein are acceleration transducers, fire-alarm sensors, water-level sensors, and magnetic contact sensors. It is also found that the wireless sensor network can deliver sensing data reliably by ad-hoc networking technology. The gateway system that can send the sensing data to server by CDMA (code division multiple access) is developed. Finally, monitoring system is constructed by web service technology, and it is observed that this system can monitor the present state of tunnel without difficulties. Furthermore, the above system provides an alternative to inspect and monitor the tunnel efficiently where the conventional wired system cannot be applied.

• Proceedings of the Korea Contents Association Conference
• /
• 2003.05a
• /
• pp.474-479
• /
• 2003

We discussed the usage of a radio resource, the spectrum allocation and the trends of policy about 5㎓ band in other countries, We studied about the technical regulation on high speed wireless access system and the spectrum allocation of ISM bard in 5㎓ bard for other countries. We also analyzed the efficient use of radio resource, the method of frequency sharing and the calculation of spec01m requirement in noel to progress the high speed wireless access system In addition We proposed the schemes of domestic spectrum allocation for high speed wireless access system at 5㎓ band

• Journal of the Optical Society of Korea
• /
• v.13 no.1
• /
• pp.98-106
• /
• 2009

This paper proposes an optical wireless transfer agent method which realizes the continuous and swift data transfer of optical wireless terminals in optical wireless networks. The unguided wireless channel generally shows frequent link disconnections and propagation delays due to weak wireless links. Specially speaking, optical wireless channels have more vulnerable links and roaming propagation delays relative to the weakness of the previous RF channels due to their low signal connectivity and small geographic coverage. Conventional optical wireless network protocols did not consider any fault models about physical link faults. Consequently, they have shown data transfer inefficiency for both data link control and physical wireless link control. To overcome these optical wireless environmental problems, this paper suggests a new wireless access point (or base station) agent system, which provides wireless or mobile clients with previous link layer protocols compensated.

• Proceedings of the KSR Conference
• /
• 2004.10a
• /
• pp.1223-1228
• /
• 2004

The study for ubiquitous computing infra is proceeding actively, it make possible to use service and access network anywhere, anytime because of wire/wireless communication technology and progress of hardware. Domestically, study for the network mobility support technology which is the key technology for future ubiquitous computing realization have progressed, but that is insufficient. Especially, there is no study for independent mobility support study about railway wireless network. So, this study propose network mobility management technology for mobile network infra in railway and proper network model in train.

• Proceedings of the KIEE Conference
• /
• 2005.04a
• /
• pp.241-243
• /
• 2005

The study for ubiquitous computing infra is proceeding actively, it make possible to use service and access network anywhere, anytime because of wire/wireless communication technology and progress of hardware. Domestically, study for the network mobility support technology which is the key technology for future ubiquitous computing realization have progressed, but that is insufficient. Especially, there is no study for independent mobility support study about railway wireless network. So, this study propose network mobility management technology for mobile network infra in railway and proper network model in train.

• Journal of Industrial Technology
• /
• v.32 no.A
• /
• pp.9-13
• /
• 2012

In this paper, we investigate maximum transmission capacity of wireless ad-hoc networks. In the investigation, we consider a network topology with regularly located nodes. For the topology, we investigate the maximum transmission capacity with RTS/CTS medium access protocol, and next, we study the maximum transmission capacity without the protocol. We see that the results of our study overall follows the result of Gupta and Kumar's research.

• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.1
• /
• pp.120-130
• /
• 2009

In recent years, many mobile wireless communication devices and applications have been deployed on the planet. The mobile multi-hop wireless network models appeared to provide means to access to networks where few infrastructure exists. However, the mobile multi-hop wireless networks have weaker points in attacks and intrusions than the wired and one-hop wireless networks. In this paper, the secure routing issues in most mobile multi-hop wireless network models are surveyed in depth. The state-of-the-art technologies and research activities are explained. Finally, the issues and technologies for the secure routing specific to a maritime network model are sufficiently discussed as conclusions.

• Journal of Digital Convergence
• /
• v.4 no.1
• /
• pp.31-41
• /
• 2006

This article introduces developing trends of an 'Ubiquitous Interface' as an access method for use of various network resources, such as public wireless networks and un-licensed wireless networks in ubiquitous sensor network environments, without troublesome settings or operations by users. 'Ubiquitous Interface' is a relatively wide sense meaning not only physical interface of specified device or between processors, but anything method for access USN. These 'Ubiquitous Interface' able to provide seamless services that adapt autonomously to the user's movements and changes in the state of wireless resources. Recently, strongly recommended current technologies are RFID, NFC, Multi-mode mobile terminal, UMA mobile terminal and Wearable computer as a future ubiquitous interface. These technologies are have to have flexibility and multiple physical communication channels for seamless service hand over and serve easy connection at huge USN to user. Also, they have to must have flexible software structure. Finally, through the 'Ubiquitous Interface', we will be experience of seamless communication and realize a real liberty of communication.

• Journal of Communications and Networks
• /
• v.4 no.4
• /
• pp.292-301
• /
• 2002

Wireless LAN technology is complementary to 3G systems and could be used to provide high bandwidth hotspot coverage, for example in railway stations and offices, in order to provide the high bandwidth video and broadband services such as those emerging on DSL fixed access. The IST Projects BRAIN and MIND have investigated a number of key technical enablers for such a system beyond 3G. These include scenarios and business models, design of an all-IP access network, consideration of ad hoc network extensions, enhancing Wireless LAN efficiency and compatibility with IP and, finally, terminal middleware and signalling for rapid adaptations to network QoS changes.