• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.05a
• /
• pp.895-896
• /
• 2015

With the development of sensor, wireless mobile communication, embedded system and cloud computing, the technologies of Internet of Things have been widely used in logistics, Smart devices security, intelligent building and o on. Bridging between wireless sensor networks with traditional communication networks or Internet, IoT gateway plays n important role in IoT applications, which facilitates the integration of wireless sensor networks and mobile communication networks or Internet, and the management and control with wireless sensor networks. The IoT Gateway is a key component in IoT application systems but It has lot of security issues. We analyzed the trends of security and privacy matters.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.11A
• /
• pp.1101-1112
• /
• 2006

With the recent growth in demand for high-data rate multimedia services in the wireless environments, the Mobile Broadband Wireless Access (MBWA) technologies, such as WiBro (Wireless Broadband internet) system, are gradually coming into the spotlight. Unlike the conventional mobile communication networks based on cellular system, the WiBro system basically consists of IP based backbone networks that will be ultimately deployed by Ipv6 (IP version six) based backbone networks according to the All-IP trend for the network evolution. In such wireless mobile environments, it is needed to support the mobility management protocol on network layer as well as physical layer and Medium Access Control (MAC) layer in WiBro system. Accordingly, in this paper, we propose a fast handover scheme for improving the handover performance in IPv6 based WiBro system and show that the proposed scheme achieves loss-free and low handover latency during inter-subnet movement of the mobile stations through the simulation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.2
• /
• pp.1027-1030
• /
• 2005

The article introduces developing trends of an adaptive mobile terminal as an interface 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. These adaptive mobile terminals able to provide seamless services that adapt autonomously to the user's movements and changes in the state of wireless resources. Consequently, adaptive mobile terminals should be had respective independent hardware structure of usable wireless networks.

• ETRI Journal
• /
• v.35 no.1
• /
• pp.27-34
• /
• 2013

This paper proposes a network-adaptive mechanism for HTTP-based video streaming over wireless/mobile networks. To provide adaptive video streaming over wireless/mobile networks, the proposed mechanism consists of a throughput estimation scheme in the time-variant wireless network environment and a video rate selection algorithm used to increase the streaming quality. The adaptive video streaming system with proposed modules is implemented using an open source multimedia framework and is validated over emulated wireless/mobile networks. The emulator helps to model and emulate network conditions based on data collected from actual experiments. The experiment results show that the proposed mechanism provides higher video quality than the existing system provides and a rate of video streaming almost void of freezing.

• Proceedings of the IEEK Conference
• /
• 2003.11c
• /
• pp.223-226
• /
• 2003

In this paper, we propose new agent discovery and route discovery schemes to support Mobile IP (MIP) in Ad Hoc networks with wireless backbone. The wireless backbone consisting of stationary wireless routers and Internet gateways (IGs) is a kind of wireless access network of IP-based core network. The proposed scheme utilizes favorable features of wireless backbone such as stable links and no energy constraints. In the agent discovery scheme, backbone-limited periodic Agent Advertisement (AA) and proxy-AA messages are used, which reduce network-wide broadcasting overhead caused by AA and Agent Solicitation messages and decentralize MIP processing overhead in IGs. In order to reduce delay time and control message overhead during route discovery far the destination outside Ad Hoc network, we propose a cache-based scheme which can be easily added to the conventional on-demand routing protocols. The proposed schemes can reduce control overhead during agent discovery and route discovery, and efficiently support MIP in Ad Hoc network with wireless backbone.

• The KIPS Transactions:PartC
• /
• v.9C no.6
• /
• pp.911-918
• /
• 2002

An important issue in the design of future Personal Communication Service (PCS) networks is the efficient management of location information. In this paper, we propose an adaptive distributed dynamic location management algorithm that stores the position of the mobile terminal in k of the n location information databases (LIDs). The proposed algorithm chooses adaptively k. replication factor according to both the space locality of LIDs in wireless mobile networks and the location query popularity to local mobile terminal from remote mobile terminals. The performance of proposed algorithm is evaluated by both an analytical model and a simulation. Based on the results of performance evaluation, we know that the performance of the proposed algorithm is better than that of Krishnamurthi's algorithm regardless of call-mobility ratio.

• Journal of Digital Contents Society
• /
• v.11 no.4
• /
• pp.433-443
• /
• 2010

In this paper, we provide a comprehensive overview and classification on a wide range of the existing location management schemes which have been reported for wireless cellular networks and Mobile IP-based networks, respectively. In addition, from the various previous literature, we derive common key conceptual techniques, their main design goals and performance considerations on them, which can provide a useful guidance for understanding location management schemes regardless of network types. The aim of this paper is not to propose a new scheme for location management, but to highlight the various key design features involved in the design of the existing location management schemes, and to enhance an insight into the fundamental principles and techniques for designing more efficient and optimized location management scheme in future wireless mobile networks. We expect that regardless of network types, these underlying fundamental principles and conceptual techniques could be also easily tailored for more efficient mobility/QoS support in future mobile computing environments.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.8 no.3
• /
• pp.857-872
• /
• 2014

Recent researches reveal that great benefit can be achieved for data gathering in wireless sensor networks (WSNs) by employing mobile data collectors. In order to balance the energy consumption at sensor nodes and prolong the network lifetime, a multi-track large-scale mobile data collection mechanism (MTDCM) is proposed in this paper. MTDCM is composed of two phases: the Energy-balance Phase and the Data Collection Phase. In this mechanism, the energy-balance trajectories, the sleep-wakeup strategy and the data collection algorithm are determined. Theoretical analysis and performance simulations indicate that MTDCM is an energy efficient mechanism. It has prominent features on balancing the energy consumption and prolonging the network lifetime.

• 한국정보통신설비학회:학술대회논문집
• /
• 2009.08a
• /
• pp.197-200
• /
• 2009

Since various type of wireless/mobile network likes WLAN, WIBRO, HSDPA were come to us, technology providing high quality multimedia service while user move are actively researched such as MIH (Media Independent Handover) proposed by IEEE for interworking between heterogeneous network and CMIP (Client Mobile IP), PMIP (Proxy Mobile IP) for mobility. Despite the technology about interworking and handover between heterogeneous network are actively researched, handover decision method need to be researched. In this paper we suggest a simple and effective handover method for high quality multimedia service in real wireless environment. For this, we use MIH+CMIP platform for target multimedia service to make handover decision rule in WIBRO and HSDPA networks. After apply this rule, we verified effectiveness of handover decision method through real test.

• Journal of Information Processing Systems
• /
• v.2 no.2
• /
• pp.107-113
• /
• 2006

It is essential to guarantee a handoff dropping probability below a predetermined threshold for wireless mobile networks. Previous studies have proposed admission control policies for integrated voice/data traffic in wireless mobile networks. However, since QoS has been considered only in terms of CDP (Call Dropping Probability), the result has been a serious CBP (Call Blocking Probability) unfairness problem between voice and data traffic. In this paper, we suggest a new admission control policy that treats integrated voice and data traffic fairly while maintaining the CDP constraint. For underprivileged data traffic, which requires more bandwidth units than voice traffic, the packet is placed in a queue when there are no available resources in the base station, instead of being immediately rejected. Furthermore, we have adapted the biased coin method concept to adjust unfairness in terms of CBP. We analyzed the system model of a cell using both a two-dimensional continuous-time Markov chain and the Gauss-Seidel method. Numerical results demonstrate that our CAC (Call Admission Control) scheme successfully achieves CBP fairness for voice and data traffic.