• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.48 no.12
• /
• pp.9-16
• /
• 2011

Most of the current mobility management protocols such as MIPv4/6 and its variants standardized by the IETF do not support global seamless handover. This is because they require comprehensive changes of the existing network infrastructure. In this article, we propose a simple mobility management protocol (SMMP) which can support global seamless handover between homogeneous or heterogeneous wireless networks. The idea is that the SMMP employs separate location management function as done in SIP to support global user and service mobility. In addition, the bidirectional tunnels are dynamically constructed to support seamless IP mobility by extending the IEEE 802.21 MIH standards. The detailed architecture and functions of the SMMP have been designed. Finally, the simulation results, using NS-2, show that the proposed SMMP outperforms the existing MIPv6 and HMIPv6 in terms of handover latency, packet loss, pear signal noise ratio (PSNR).

• Journal of Korea Multimedia Society
• /
• v.8 no.2
• /
• pp.258-268
• /
• 2005

The efficient provision of multicast service to moving hosts in mobile computing environments is not so easy task. Bi-directional tunneling scheme causes overhead about encapsulation and triangular routing. On the other hand, remote subscription scheme need freDuent tree reconstruction, which is inefficient for rapid moving hosts. In this paper we propose Mobility Based Mobile Multicast(MBMOM) scheme which is based on host's mobility information. Ultimately MBMOM try to find the strong points of remote subscription scheme and hi-directional tunneling scheme. If host's mobility speed is considered to be high, multicast packets are forwarded using hi-directional tunneling scheme from home agent continuously. If host's mobility speed is considered to be slow, remote subscription scheme is applied for foreign agent and it try to join multicast tree. We developed analytical models to analyze the performance of proposed scheme and simulated our scheme compared with MOM(Mobile Multicast), RBMOM(Range Based MOM), and TBMOM(Timer Based MOM) schemes. Simulation results show that our scheme has shorter transmission delay than above 3 schemes in the aspect of host's mobility speed and multicast group size.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.9B
• /
• pp.857-866
• /
• 2009

Recently, IP mobility study of infra's common elements is undergoing processes to achieve FMC based on All-IP. Existing typical mobility technology based on IP is IETF's Mobile IP. However, it faced to limitations due to packet loss, delays when MN is moving on Mobile IP, also existing network infra - routers (FA)-needed to add/change the functions to support Mobile IP. In this paper, existing mobility problems based on IP and the suggested improvements for platforms which support mobility, quality, security are proposed. It discusses the performance on the current existing IP infrastructure derived from simulation analysis on mobility packet loss and delay. From the resulting data, improvements will also be outlined for optimal performance.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.1
• /
• pp.97-107
• /
• 2012

The Internet is becoming increasingly diverse and complex, the needs of user's convenience is also various and increased. The task forces have been working on how to design the future Internet in satisfaction of user's require and mobility management is one of the key issues to be considered. mobility management in the future Internet is still being designed in an "all-in-one" way where all management functions are tightly kept at a single location and this results in cost inefficiency that can be an obstruction to constructing flexible systems. In this paper, we propose a cost-effective function-distributed mobility management scheme that can enable more flexible future Internet construction. Furthermore, we show the effectiveness of our proposed system via a cost analysis and computer simulation with a random walk mobility model.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.6B
• /
• pp.411-419
• /
• 2008

As the set of new mobile data networking service technologies, such as WiBro, mobile WiMAX and WCDMA-HSDPA, have been introduced in recent years, IP mobility management protocols which aim to provide seamless IP service over the mobile networking environment become one of the important building blocks for the successful mobile networks. IETF has introduced a basic mobility management protocol over IPv6 (MIPv6) and a set of enhanced protocols such as FMIPv6 and HMIPv6, followed by FHMIPv6, S-MIPv6 and HIMIPv6 which combine the benefits of the basic protocols. We have studied the impact of the various IP mobility management protocols over TCP sessions through extensive simulations with ns-2. Our simulation results show that TCP performance with the HIMIPv6 outperforms MIPv6, FMIPv6 and HMIPv6 over the various TCP protocols, due to its efficient combination of the hierarchical mobility management scheme of the HMIPv6, the predictive handover scheme of the FMIPv6 and the fast simulcasting scheme of the S-MIP.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.44 no.12
• /
• pp.54-62
• /
• 2007

Mobile IPv6 is the representative standard protocol proposed to offer mobility of mobile hosts, but it has drawbacks such as high handover latency and packet loss during handover. To complement these drawbacks, several protocols have been proposed and they can support faster handover than the Mobile IPv6, but there still exists inevitable packet loss during handover in those protocols. In this paper, we propose a new handover procedure of mobile host who has a dual link for minimizing packet loss rate during micro handover to improve mobility capability of Cellular Ethernet system that supports mobility at layer 2. And we derive the superiority of proposed scheme by comparing in terms of packet loss rate, handover latency and throughput of proposed scheme with those of Hierarchical Mobile IPv6 which is the representative IP-layer micro mobility protocol by simulation.

• KIPS Transactions on Computer and Communication Systems
• /
• v.1 no.3
• /
• pp.205-218
• /
• 2012

Mobility management of the mobile nodes and provision of seamless handover is crucial to an efficient support for the global roaming of the mobile nodes in next-generation wireless networks. Mobile IPv6 and mobility management in extended IP layer, which highly depend on traffic characteristics and user mobility models, were proposed by the IETF. Therefore, to evaluate the in-depth performance about these factors is important. Generally, the performance of IPv6-based mobility management protocol is evaluated through simulation. This paper shows the correlation between network parameters and performance metrics through numerical results, which is investigated how influence handoff latency and packet loss. And this paper uses mathematical analysis of the system parameters, such as the subnet residence time, the packet arrival rate and delay in wireless connection through the analytical framework which evaluate the performance of IPv6-based mobility management protocol.

• Journal of Korea Multimedia Society
• /
• v.11 no.4
• /
• pp.544-553
• /
• 2008

The general sensor network uses bundle method to collect fixed information from sensor node. However, this method is difficult to actively cope with major sensing objects in healthcare environment including status and position change of person and change of surrounding environment. In order to support the healthcare environment, certain information should be provided in accordance with the change of status of person and surrounding circumstance and also must cope with the change of network type by movement of person. This paper analyzes LEACH protocol which guarantees effectiveness of network as it constitutes clusters between Agilla model that is a representative multi agent middle ware and surrounding nodes. Based on the result of this analysis, it suggests LEACH_Mobile protocol which guarantees node mobility that is the weakest point of LEACH protocol. Moreover, it designs mobility agent middleware which supports dynamic function change of node and mobility agent module which supports dynamic function change of mobile node as components of LEACH_Mobile routing module. In addition, it is definitely increase performance which in mobile node of transfer data rate through LEACH_Mobile protocol of simulation result.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.19 no.6
• /
• pp.118-133
• /
• 2020

Research interest in the Mobility-as-a-Service (MaaS) concept for enhancing users' mobility experience is increasing. In particular, dynamic pricing techniques based on reinforcement learning have emerged since adjusting prices based on the demand is expected to help mobility services, such as taxi and car-sharing services, to gain more profit. This paper provides a simulation framework that considers more practical factors, such as demand density per location, preferred prices, the distance between users and drivers, and distance to the destination that critically affect the probability of matching between the users and the mobility service providers (e.g., drivers). The aforementioned new practical features are reflected on a data structure referred to as the Matching Matrix. Using an efficient algorithm of computing the probability of matching between the users and drivers and given a set of precisely identified high-demand locations using HDBSCAN, this study developed a better reward function that can gear the reinforcement learning process towards finding more realistic dynamic pricing policies.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.17 no.2
• /
• pp.288-293
• /
• 2017

Transient simulation capability with an implicit time derivation method is a missing feature in deterministic Boltzmann equation solvers. The H-transformation, which is critical for the stable simulation of nanoscale devices, introduces difficulties for the transient simulation. In this work, the transient simulation of graphene sheets is reported. It is shown that simulation of homogeneous systems can be done without abandoning the H-transformation, as much as a specially designed discretization method is employed. The AC mobility and step response of the graphene sheet on the $SiO_2$ substrate are simulated.