Author
Sungwon Lee
Other affiliations: Korea Polytechnic University, Samsung, University of Maryland University College
Bio: Sungwon Lee is an academic researcher from Kyung Hee University. The author has contributed to research in topics: Wireless network & Cognitive radio. The author has an hindex of 23, co-authored 150 publications receiving 1646 citations. Previous affiliations of Sungwon Lee include Korea Polytechnic University & Samsung.
Papers published on a yearly basis
Papers
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TL;DR: A data-centric multiobjective QoS-Aware routing protocol, called DMQoS, is proposed, which facilitates the system to achieve customized QoS services for each traffic category differentiated according to the generated data types.
Abstract: In this paper, we address Quality-of-Service (QoS)-aware routing issue for Body Sensor Networks (BSNs) in delay and reliability domains. We propose a data-centric multiobjective QoS-Aware routing protocol, called DMQoS, which facilitates the system to achieve customized QoS services for each traffic category differentiated according to the generated data types. It uses modular design architecture wherein different units operate in coordination to provide multiple QoS services. Their operation exploits geographic locations and QoS performance of the neighbor nodes and implements a localized hop-by-hop routing. Moreover, the protocol ensures (almost) a homogeneous energy dissipation rate for all routing nodes in the network through a multiobjective Lexicographic Optimization-based geographic forwarding. We have performed extensive simulations of the proposed protocol, and the results show that DMQoS has significant performance improvements over several state-of-the-art approaches.
146 citations
TL;DR: This work proposes an enhanced synchronization algorithm to calculate the asymmetric ratio of the communication link, and the proposed algorithm enhances an accuracy of the time synchronization.
Abstract: IEEE 1588 is a standard to synchronize independent clocks running on separate nodes of a distributed measurement and control system. In IP based cellular network, it is considered as a key technology to synchronize base stations. Especially, interests for the low-cost and very-small home cellular base station called the Femtocell is increasing, and it is connected to the cellular core network using an asymmetric communication link such as xDSL. However, the conventional IEEE 1588 synchronization algorithm assumes symmetrical links, and makes errors for asymmetric links for the calculation of the time difference between the master clock (a clock source) and the slave clock (a clock consumer). We propose an enhanced synchronization algorithm to calculate the asymmetric ratio of the communication link, and the proposed algorithm enhances an accuracy of the time synchronization.
101 citations
TL;DR: An Efficient and Reliable MAC protocol for VANETs (VER-MAC) is proposed which allows nodes to broadcast safety packets twice during both the control channel interval and service channel interval to increase the safety broadcast reliability.
Abstract: Vehicular Ad hoc Network (VANET) is developed to enhance the safety, comfort and efficiency of driving. The IEEE 802.11p/WAVE and IEEE 1609.4 family are standards intended to support wireless access in VANETs. In this paper, we propose an Efficient and Reliable MAC protocol for VANETs (VER-MAC) which allows nodes to broadcast safety packets twice during both the control channel interval and service channel interval to increase the safety broadcast reliability. By using the additional data structures, nodes can transmit service packets during the control channel interval to improve the service throughput.
64 citations
15 Sep 2010
TL;DR: This work focuses on the uplink traffic aggressiveness characteristics in major applications such as Smart Grid, and proposes a new congestion avoidance algorithm to reduce the congestion of the uplinks intensive applications.
Abstract: Machine-Type-Communication (MTC) is a new paradigm in mobile wireless network domains such as Mobile WiMAX (IEEE 802.16e) and 3GPP LTE (3rd Generation Partnership Project Long Term Evolution). We explain the background for MTC environments, and its key issues. Then we focus on the uplink traffic aggressiveness characteristics in major applications such as Smart Grid. Then, we propose a new congestion avoidance algorithm to reduce the congestion of the uplink intensive applications.
60 citations
TL;DR: An overview of these standards from the media access control technology perspective is provided, and the similarities and dissimilarities between the IEEE 1901 and ITU-T G.hn standards are discussed, as well as potential performance issues.
Abstract: Power lines are becoming increasingly popular for high-speed communications, while at the same time reliable communications over them poses several unique challenges. Recently, two standardization bodies, the Institute of Electrical and Electronics Engineers (IEEE) and the International Telecommunication Union (ITU), addressed in their IEEE 1901 and ITU-T G.hn standards, respectively, both the medium access control and the physical layer specifications of power line communications. In this article, we provide an overview of these standards from the media access control technology perspective, and the similarities and dissimilarities between the IEEE 1901 and ITU-T G.hn standards are discussed, as well as potential performance issues. We use a top-down approach to analyze the features and technologies of the standards.
56 citations
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01 May 1975
TL;DR: The Fundamentals of Queueing Theory, Fourth Edition as discussed by the authors provides a comprehensive overview of simple and more advanced queuing models, with a self-contained presentation of key concepts and formulae.
Abstract: Praise for the Third Edition: "This is one of the best books available. Its excellent organizational structure allows quick reference to specific models and its clear presentation . . . solidifies the understanding of the concepts being presented."IIE Transactions on Operations EngineeringThoroughly revised and expanded to reflect the latest developments in the field, Fundamentals of Queueing Theory, Fourth Edition continues to present the basic statistical principles that are necessary to analyze the probabilistic nature of queues. Rather than presenting a narrow focus on the subject, this update illustrates the wide-reaching, fundamental concepts in queueing theory and its applications to diverse areas such as computer science, engineering, business, and operations research.This update takes a numerical approach to understanding and making probable estimations relating to queues, with a comprehensive outline of simple and more advanced queueing models. Newly featured topics of the Fourth Edition include:Retrial queuesApproximations for queueing networksNumerical inversion of transformsDetermining the appropriate number of servers to balance quality and cost of serviceEach chapter provides a self-contained presentation of key concepts and formulae, allowing readers to work with each section independently, while a summary table at the end of the book outlines the types of queues that have been discussed and their results. In addition, two new appendices have been added, discussing transforms and generating functions as well as the fundamentals of differential and difference equations. New examples are now included along with problems that incorporate QtsPlus software, which is freely available via the book's related Web site.With its accessible style and wealth of real-world examples, Fundamentals of Queueing Theory, Fourth Edition is an ideal book for courses on queueing theory at the upper-undergraduate and graduate levels. It is also a valuable resource for researchers and practitioners who analyze congestion in the fields of telecommunications, transportation, aviation, and management science.
2,562 citations
TL;DR: The current state-of-art of WBANs is surveyed based on the latest standards and publications, and open issues and challenges within each area are explored as a source of inspiration towards future developments inWBANs.
Abstract: Recent developments and technological advancements in wireless communication, MicroElectroMechanical Systems (MEMS) technology and integrated circuits has enabled low-power, intelligent, miniaturized, invasive/non-invasive micro and nano-technology sensor nodes strategically placed in or around the human body to be used in various applications, such as personal health monitoring. This exciting new area of research is called Wireless Body Area Networks (WBANs) and leverages the emerging IEEE 802.15.6 and IEEE 802.15.4j standards, specifically standardized for medical WBANs. The aim of WBANs is to simplify and improve speed, accuracy, and reliability of communication of sensors/actuators within, on, and in the immediate proximity of a human body. The vast scope of challenges associated with WBANs has led to numerous publications. In this paper, we survey the current state-of-art of WBANs based on the latest standards and publications. Open issues and challenges within each area are also explored as a source of inspiration towards future developments in WBANs.
1,359 citations
16 May 2011
TL;DR: In this article, the authors provide an overview of what PLC can deliver today by surveying its history and describing the most recent technological advances in the area and discuss the main conclusions one can draw from the literature on these subjects.
Abstract: Are Power Line Communications (PLC) a good candidate for Smart Grid applications? The objective of this paper is to address this important question. To do so, we provide an overview of what PLC can deliver today by surveying its history and describing the most recent technological advances in the area. We then address Smart Grid applications as instances of sensor networking and network control problems and discuss the main conclusions one can draw from the literature on these subjects. The application scenario of PLC within the Smart Grid is then analyzed in detail. Because a necessary ingredient of network planning is modeling, we also discuss two aspects of engineering modeling that relate to our question. The first aspect is modeling the PLC channel through fading models. The second aspect we review is the Smart Grid control and traffic modeling problem which allows us to achieve a better understanding of the communications requirements. Finally, this paper reports recent studies on the electrical and topological properties of a sample power distribution network. Power grid topological studies are very important for PLC networking as the power grid is not only the information source but also the information delivery system-a unique feature when PLC is used for the Smart Grid.
1,084 citations
TL;DR: In this article a coverage and interference analysis based on a realistic OFDMA macro/femtocell scenario is provided, as well as some guidelines on how the spectrum allocation and interference mitigation problems can be approached in these networks.
Abstract: OFDMA femtocells have been pointed out by the industry as a good solution not only to overcome the indoor coverage problem but also to deal with the growth of traffic within macrocells. However, the deployment of a new femtocell layer may have an undesired impact on the performance of the macrocell layer. The allocation of spectrum resources and the avoidance of electromagnetic interference are some of the more urgent challenges that operators face before femtocells become widely deployed. In this article a coverage and interference analysis based on a realistic OFDMA macro/femtocell scenario is provided, as well as some guidelines on how the spectrum allocation and interference mitigation problems can be approached in these networks. Special attention is paid to the use of self-configuration and self-optimization techniques for the avoidance of interference.
892 citations
01 Jan 2004
TL;DR: This chapter contains sections titled: Introduction Overview of Multicarrier CDMA Systems Channel Model Performance of MC-CDMA System Performance of Overlapping MulticARrier DS-CDma Systems Performance of MultICarrier DS/MC systems Performance of AMC systems performance of SFH/MC DS/CDMA systems.
Abstract: This chapter contains sections titled: Introduction Overview of Multicarrier CDMA Systems Channel Model Performance of MC-CDMA System Performance of Overlapping Multicarrier DS-CDMA Systems Performance of Multicarrier DS-CDMA-I Systems Performance of AMC DS-CDMA Systems Performance of SFH/MC DS-CDMA Systems Chapter Summary and Conclusion
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511 citations