Won-Kyeong Seo

Global Mobility Management Scheme with Interworking between PMIPv6 and MIPv6

The network-based mobility management scheme, proxy mobile IPv6 (PMIPv6), was recently proposed by the IETF NetLMM WG. In a PMIPv6 domain, an mobile node (MN) mobility can be provided without any mobility protocol stack, such as Mobile IPv6 (MIPv6). However, since the PMIPv6 protocol was only designed for local mobility management, MN mobility cannot be supported outside a PMIPv6 domain. Accordingly, to support global mobility management, we propose an interworking scheme between PMIPv6 and MIPv6, including integrated functional architecture between local mobility anchor function (LMAF) and home agent function (HAF), explicit HoA configuration, Home Network Prefix (HNP) allocation mechanism, and handover procedure. Simulation results demonstrate that the proposed scheme can support the global mobility management by interworking between PMIPv6 and MIPv6. And they also show that the proposed scheme has an outstanding TCP/UDP throughput when compared with other schemes.

Design and development of a u-Health system based on the ISO/IEEE 11073 PHD standards

An increase in human life expectancy due to the development of medical techniques has led to many social problems such as rapidly aging populations in many industrialized countries, increased medical expenses and a lack of medical specialists. Thus, studies on improving the quality of life with the least amount of expense have been conducted by incorporating advanced technology, especially for PHDs (Personal Health Device), into the medical service market. Recently, the Continua Alliance, IEEE Standards Association, and the IEEE-EMBS affiliated 11073 Personal Health Data Working Group have been studying techniques to guarantee the compatible extensibility of the u-Health system by defining standards, which manage and send information from the users of PHDs. However, compatibility and extensibility among manufacturers of PHDs have not been taken into account in most of the studies done on the development of PHDs because most of them have been supported by individual medical organizations. Therefore, the aim of this study was to design and develop a u-Health system for smart phones with the ISO/IEEE 11073 PHD standards, which were able to provide medical services anytime and anywhere.

A Network-Assisted Femto Base Station Management Scheme in IEEE 802.16e System

In the WIMAX (IEEE 802.16e) femtocell environment, serving Base Station (BS) should periodically broadcast neighbor BS information including femtocell to support mobility. As a neighbor list increases, it leads to increasing scanning overheads and wasting air resources. Hence, in this paper we propose a network-assisted femto BS management scheme, using a triangulation mechanism and a femto BS monitoring scheme. The simulation results show that the proposed scheme improves scanning performance and avoids wasting air resources compared with the conventional scheme of IEEE 802.16e system.

A Multihoming Support Scheme with Localized Shim Protocol in Proxy Mobile IPv6

This paper proposes an enhanced multihoming support scheme based on combining ideas from both the Shim and Proxy Mobile IPv6 (PMIPv6) protocols. The proposed scheme not only resolves the multihoming support problems with the current PMIPv6, but also provides mobility support to the Shim protocol. In the proposed scheme, the Shim protocol is locally used between a multihomed Mobile Node (MN) and the Local Mobility Anchor (LMA) in the PMIPv6 domain. A flow distribution scheme with the Shim locator preferences is proposed to provide flexible multihoming. Simulation results show that the PMIPv6 combined with the localized Shim protocol can support both mobility and multihoming efficiently.

Mobility adaptive hybrid routing for mobile ad hoc networks

Mobile Ad-hoc Networks (MANETs) require a dynamic and efficient routing protocol that can respond quickly to network topology changes. Ad hoc routing protocols for MANETs are classified into: (a) proactive, (b) reactive and (c) hybrid approaches. In general, proactive routing is more suitable for a stationary network, while reactive routing is better for a mobile network with a high mobility. In many applications, a node in a MANET is mobile, yet it can also fluctuate between being mobile and being stationary. Thus, a hybrid routing approach with the ability to adapt to the node mobility could improve the performance of MANETs. In this paper, we propose a Mobility Adaptive Hybrid Routing (MAHR) for MANETs, which varies its routing between reactive approach and proactive approach to adapt to node mobility. The MAHR consists of three parts: (a) calculation of mobility ratio, (b) core node selection, and (c) procedure of hybrid routing. The simulation results showed that MAHR could achieve the advantages of both reactive and proactive routing approaches in performance.

Design and Development of Personal Healthcare System Based on IEEE 11073/HL7 Standards Using Smartphone

The increased life expectancy of human due to the advance of medical techniques has led to many social problems such as rapidly aging populations, increased medical expenses and a lack of medical specialists. Thus, studies on improving the quality of life with the least amount of expense have been going on by incorporating advanced technologies, especially for Personal Health Devices (PHDs), into the medical service market. However, compatibility and extensibility among manufacturers of PHDs have not been taken into account in most of the researches done on the development of PHDs because most of them have been supported by individual medical organizations. The interoperability among medical organizations can not be guaranteed because each medical organization uses different format of the messages. Therefore, in this paper, an expansion module that can enable commercially-available non-standard PHDs to support the IEEE 11073, and a smart-phone-based manager that can support easy and comprehensive management on receiving and transmitting the collected data from each PHD using IEEE 11073 standard were developed. In addition, a u-health system that can transmit the data collected in the manager using the standard data format HL 7 to medical center for real-time medical service from every medical institutions that support this standard was designed and developed.

Handover decision algorithm based on available data volume in hierarchical macro/femto-cell networks

Hierarchical macro/femto-cell networks are considered a promising technology to increase overall network coverage and bandwidth at a relatively low cost. In these emerging networks, a large number of femtocells are deployed within a macrocell. When a macrocell includes many femtocells, the number of handovers greatly increases because handover from the macrocell to the femtocell is executed frequently. However, frequent handovers increase overhead due to handover management as well as latency due to handover interruption. In this paper, we propose an efficient handover decision algorithm based on available data volume to reduce the unnecessary handovers and increase the throughput. The simulation results show that the proposed algorithm effectively reduces the number of unnecessary handovers while improving the throughput compared to a conventional RSS based algorithm.

Enhanced PRoPHET routing protocol that considers contact duration in DTNs

PRoPHET is a probabilistic routing protocol for Delay Tolerant Networks (DTNs). In PRoPHET, the delivery probability is calculated based on the history of encounters and transitivity. However, if two nodes meet frequently during a short time interval, the delivery probability between these nodes increases rapidly. To solve this problem, PRoPHETv2 uses the inter-meeting time. Yet, the contact duration is still not considered. Therefore, this paper proposes an enhanced PRoPHETv2 routing protocol that considers the contact duration. Simulation results show that the proposed scheme outperforms PRoPHETv2 in terms of the delivery ratio and overhead ratio.

NAV-based Load Aware Routing protocol in Wireless Mesh Networks

We propose a Network Allocation Vector (NAV) based Load Aware Routing (NA-LAR) protocol for Wireless Mesh Networks. NA-LAR is basically based on the Directional AODV (D-AODV)) to reduce the number of route request packet broadcast by using a restricted directional flooding technique. It also considers network conditions with NAV which indicates the busyness of the medium in IEEE 802.11, and it is used to find load balanced routing path. Thus, NA-LAR can find a less loaded route, and it leads to network performance improvement. Simulation results show that NA-LAR compared with D-AODV could increase the total throughput and reduce the end-to-end delay.

Efficient NEMO support scheme with direct HNP assignment in PMIPv6

This paper proposes an efficient network mobility support scheme with direct home network prefix (HNP) assignment to reduce the location update cost and packet tunneling cost. Since the HNP of a Mobile Network Node (MNN) is directly assigned by the moving mobile access gateway (mMAG), instead of the local mobility anchor (LMA), using a sub-prefix of the mMAGs HNP, the proposed scheme minimizes both the location update and the packet tunneling cost without any additional extension of the PMIPv6 protocol. Numerical results show that the proposed scheme outperforms the existing schemes.