Dae-Geun Park

A method to dynamically configure the multicast and broadcast service zone in mobile WiMAX

In this paper, we look into the problem of a waste of wireless resource in MBS (Multicast & Broadcast Service) zone which is proposed by IEEE 802.16e standards to provide the MBS to many subscribers at the same time. We introduce a new method to reduce the amount of wireless resources to be wasted. And then, we will show that the proposed method can use the wireless resource more effectively than the original MBS zone by simulation.

Packet error rate measurement using IEEE 802.15.4-based modem on the Korea high-speed train

In this paper, the performance of an IEEE 802.15.4 based modem designed to monitor the state of underbody parts related to the security of high speed trains is investigated. Based on the intensive field tests, the optimum positions of transmitter and receiver within the high speed train are proposed. The validities of the proposed scheme is verified with packet error rate (PER) measured at the several points of high speed trains.

Implementation of IPTV Set-Top for Distance Education Services Using Grid-CDN

To backup the remote education service, the software architecture of IPTV Set-Top device embedding Grid-CDN (Content Delivery Network) based on mesh-pull P2P (Peer-to-Peer) technology has been identified. In this paper, we proposed a method supporting a remote education service such as 1:1 or 1:N between subscribers over IPTV service networks, and implemented on a IPTV Set-Top device. In addition, to validate the performance of the IPTV Set-Top device we show that demonstration, including 1:1 or 1:N education services, on IPTV(Internet Protocol Television) service networks.

Evaluation of communication channel for train safety monitoring system

In this paper, we will introduce the necessity of real-time safety monitoring system for high-speed railway vehicle and propose a new type of safety monitoring system using a low-power wireless connection. To verify the proposed safety monitoring system is feasible, we measure the packet error rate on the moving train and show the analyzed results.

Implementation of mobile relay system for supporting adjustable time division duplex.

In this paper, we will introduce the relay system based on time division duplexing technology. Especially, we suggest various frame structure to adjust the throughput ratio of downlink and uplink. Finally, we show the test results of relay system we developed.