Choong Kyo Jeong

Design of hybrid authentication scheme and key distribution for mobile multi-hop relay in IEEE 802.16j

Mobile multi-hop relay (MMR) network is known to have the strength of easy installation and convenient management because of its self-organizing and self-healing characteristics. However, MMR is also known to be vulnerable to security problems for the very same reason. In this paper, we propose a new hybrid authentication algorithm for IEEE 802.16j MMR network service. The proposed scheme uses centralized authentication when a mobile station (MS) or a relay station (RS) initially joins the MMR network, and uses distributed authentication for hop-by-hop authentication between the mobile nodes. We analyze the procedure of the proposed scheme in detail, and examine its usefulness when applied to the MMR network. The proposed scheme can be used in any mobile multi-hop network as well as IEEE 802.16j MMR network.

Performance analysis of authentication and key distribution scheme for mobile multi-hop relay in IEEE 802.16j

Mobile multi-hop relay (MMR) network is known to be easy to install and convenient to manage because of its self-organizing and self-healing characteristics. However, MMR is vulnerable to security problems because of the same reason. In this paper, we propose a new hybrid authentication and key distribution algorithm for IEEE 802.16j MMR service. The proposed scheme uses centralized authentication when a mobile station or a relay station initially joins the MMR network and uses distributed authentication for hop-by-hop authentication between mobile nodes. We examine the procedure of the proposed scheme and its usefulness when applied to MMR networks. We also analyze the performance of the hybrid scheme. The proposed scheme can be used in any mobile multi-hop network as well as IEEE 802.16j MMR network.

Bio-AdHoc Sensor Networks for Early Disaster Warning

Ad-hoc networks do not need any preexisting network infrastructure and have been developed as temporal networks in various fields. An infostation is a system to relay information that is not delay-sensitive. In this paper, we propose an early disaster warning system built on infostations and an adhoc network composed of sensors attached to moving animals. We analyze the performance of the proposed system by simulation. The analysis results show that the proposed system will be very useful in the early detection of big forest fires which occur frequently in Korea mountain areas.

A Contents Service Profit Model Based on the Quality of Experience and User Group Characteristics

Generally, it is known that only quality-assuring services can provide a reasonable profit model. However until now a practical profit model considering the service cost and quality simultaneously has not been introduced yet. Recently, the Quality of Experience (QoE) was suggested to measure user’s real satisfaction level. The QoE is expected to be used for efficient service provisioning and criteria for accurate satisfaction measuring. This paper introduces a profit model for the contents providers considering the costs for quality services and the QoE together. Especially, we assume that the QoE with user’s feedback can be interpreted as the intention to pay for the services. We take into account that QoE is dependent on service area, demographic information and user group characteristics. The proposed profit model can be used for contents providers to find an optimum investment which maximizes the profit.

Throughput Analysis of Non-Transparent Mode in IEEE 802.16j Mobile Multi-Hop Relay Networks

In IEEE 802.16j MMR protocol, two modes about usage of RS are proposed; one is transparent mode to enhance data throughput and the other is non-transparent mode to extend coverage. In this paper, we focus on non-transparent mode and find that the mode can also improve data throughput. Therefore, we analyze data throughput on various RS topology and their extended coverage area by simulation in IEEE 802.16j non-transparent mode. We also compare the simulation results with the single MR-BS system of which coverage is extended by higher transmission power. From the comparisons of simulation results, we see that higher throughput can be obtained in the proposed non-transparent mode.

Packet diversity in wireless uplink channels

A packet diversity scheme is introduced to increase uplink channel efficiency in a wireless network where forward error correction is used. The packet diversity allows neighbor base stations to receive uplink packets from a mobile terminal in order to increase the efficiency of the uplink channel. By allowing multiple base stations to receive the same packets, we can improve the error correction capability in an uplink channel. By incorporating the packet diversity we can reduce the parity overhead of each packet for a given tolerable loss probability, which improves the link efficiency.