In-Yeup Kong

Lifetime Maximization by Cross-Layer Interaction in Wireless Sensor Networks

We consider the cross-layer design considering physical layer, MAC layer, and network layer to maximize the lifetime of energy-constrained wireless sensor network. Our solution is based on system model that considers reliability as well as physical layer (i.e., power control), data link layer (i.e., and link scheduling) and network layer (i.e., routing protocol) jointly. To obtain more energy-efficient solution for lifetime maximization of wireless sensor networks, we enhance existing cross-layer model using energy-efficient MAC protocol and energy-consumption model instead of TDMA

Trade-off between reliability and energy-efficiency in Transport Protocol for Wireless Sensor Networks

Efficient design and implementation of wireless sensor networks has become a hot area of research in recent years. In comparison with other existing networks, wireless sensor networks (WSN) have some limitations. Typically, nodes in WSN have limited power, computational capacity, and memory. These problems require the need of having particular protocols designed for WSN. Currently, many research focused on developing transport protocols. This paper proposes a probability model that can be applied in transport protocols using hop-by-hop and end-to-end mechanism. From this model, we evaluate the number of hops that a packet has to pass when it is being sent from source to destination. We also solve the optimal number of transmissions in transport layer. The result from this model shows that there is a trade-off between reliability and energy-efficiency

Opportunistic Scheduling with Power Control in Ad Hoc Wireless Networks

To exploit the multiuser diversity in the CSMA/CA based wireless ad hoc networks, this paper proposes a new algorithm for opportunistic scheduling that will take advantage of both multiuser diversity and power control. The scheduling scheme is performed first before power control to further enhance throughput. The scheduling scheme ensures that the transmission is successful since a best candidate receiver is chosen for transmission and hence minimizes retransmissions. Likewise, the power control algorithm helps reduce interference between links and maximizes spatial reuse. In our study, we provided the scheduling scheme and the power control algorithm. We also showed optimal solutions for minimizing power consumption and maximizing net utility

A performance analysis model of PC-based software router supporting IPv6-IPv4 translation for residential gateway

This paper presents a queuing analysis model of a PC-based software router supporting IPv6-IPv4 translation for residential gateway. The propose models are M/G/1/K or MMPP-2/G/1/K by arrival process of PC-based software router. In M/G/1/K, the arrival process is assumed to be Poisson process which is independent, identically distributed. In MMPP-2/G/1/K, The arrival process is assumed to be two-state Markov modulated Poisson process (MMPP). MMPP-2/G/1/K model is used to represent self-similar traffic. The service time distribution is arbitrary. The service discipline of server is processor sharing. The total number of packets that can be processed at one time is limited to K. We obtain PC-based software router performance metrics such as system sojourn time, blocking probability and throughput. The parameters are estimated by maximizing the log-like hood function of the measured average response time. The model has been validated through measurements. The performance metrics predicted by the model fit well to the experimental outcome.

Wireless sensor network renewable energy source life estimation

Sensor applications are gaining popularity in health applications particularly in environmental monitoring and patient monitoring. Some applications include monitoring of C02 concentration in home environment, pulse monitoring for in-house patients, and monitoring of medicine distribution in hospitals. Sensors can be deployed in the target environment or in some cases, worn by the monitored patient. Data from these deployed sensor are then stored in a database for future analysis by medical professionals. Reliability and accuracy of data is considered for medical application. This paper presents a simple model for renewable energy source in the deployed sensors. Using solar energy model concepts and battery mechanism, we stochastically tried to model the behavior of rechargeable energy sources used for wireless sensor networks. This model can then be used as cost function for providing efficient routing and good quality of service.

Design and implementation of ontology-based context reasoning engine for adaptive multimedia service migration

Recently, a demand of adaptive multimedia service, which supports multimedia service migration according to users location and characteristics of user device, is increased. In this paper, we propose a service migration system, which becomes aware of user device using intelligent agent. And we design and implement the ontology-based intelligent agent, which is aware of the context in its environment. Moreover, we implement a context reasoning system using location information.

Wireless Sensor Network Renewable Energy Source Life Estimation

Sensor applications are gaining popularity in health applications particularly in environmental monitoring and patient monitoring. Some applications include monitoring of C02 concentration in home environment, pulse monitoring for in-house patients, and monitoring of medicine distribution in hospitals. Sensors can be deployed in the target environment or in some cases, worn by the monitored patient. Data from these deployed sensor are then stored in a database for future analysis by medical professionals. Reliability and accuracy of data is considered for medical application. This paper presents a simple model for renewable energy source in the deployed sensors. Using solar energy model concepts and battery mechanism, we stochastically tried to model the behavior of rechargeable energy sources used for wireless sensor networks. This model can then be used as cost function for providing efficient routing and good quality of service.

Design and implementation of IPv6-IPv4 protocol translation system using dynamic IP address

With the development of IPv6, several IPv6-IPv4 protocol translation systems for communicating between IPv6 networks and IPv4 networks have been proposed. However, the existing IPv6-IPv4 protocol translation systems are impossible to deploy IPv6 networks using dynamic IP address because they necessarily require predefined IP address space for protocol translation. In this paper, we design and implement the IPv6-IPv4 protocol Translation System using Dynamic IP address (64TSD). In order to verify the feasibility of 64TSD, we present experimental results with variable applications and performance evaluation results.

Design and emulation of integration framework for heterogeneous wireless PAN networks

WPANs (Wireless personal area networks) vary greatly by nature with regard to requirements such as data rate, coverage, subscriber volume, and supported mobile velocity. Mobile devices with multiple network interfaces are very common and to make these multi-mode devices communicate with any WPAN device at anytime, anywhere, a framework for heterogeneous wireless networks is essential. Therefore, we propose an integration framework that handle heterogeneous WPAN protocols simultaneously in a unified ways. In this paper, we explain the requirements and detailed design of our framework, and then present the emulation test results.

Joint Optimization of Link Scheduling, Power Control, and Routing in Ad Hoc Wireless Networks

Cross-layer design is an extensive research area in ad hoc wireless networks and is particularly important under energy constraints. The physical layer, link layer, and network layer are known to have great impact on network performance as well as on energy consumption; hence, the interactions between these layers should be studied. In this paper, we formulate an optimal link scheduling and power control policy that supports a particular data rate on each link in the network while satisfying the Signal to Interference plus noise ratio (SINR) and the maximum transmission power constraints at each node. We present an optimization problem considering both the energy consumed of each node in the routing path and the delay associated on each link as the link cost metrics. The problem is to find an optimal link scheduling, power control and routing policy that minimizes the end-to-end delay as well as the energy link cost subject to certain constraints. We provide numerical examples for our schemes and relationships between the parameters i.e. the higher the required data rate and the higher the SINR requirement; the system will become less energy-efficient since a high transmission power is needed. This paper is a preliminary step towards our distributed joint scheduling, power control and routing algorithm for ad hoc networks using cross layer approach