• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.4
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• pp.321-326
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• 2015

Smart metering is one of the most implementable internet-of-thing service. In order to implement the smart metering, a wireless communication network should be newly designed and evaluated so as to satisfy quality-of-service of smart metering. In this paper, we consider a wireless network for the smart metering implemented with multi-purpose wireless chips and channel coding-functioned micro controllers. Especially, channel coding is newly adopted to improve successful frame transmission probability. Based on the successful frame transmission probability, average transmission delay and delay violation probability are analyzed. Using the analytical results, service coverage expansion is evaluated. Through the delay analysis, service feasibility can be verified. According to our results, channel coding needs not to be utilized to improve the delay performance if the smart metering service coverage is several tens of meters. However, if more coverage is required, chanel coding adoption definitely reduces the delay time and improve the service feasibility.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.3
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• pp.107-115
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• 2009

Traditionally, simulation method is used to test and evaluate the performance of communication protocol or functional elements for mobile communication service. In this paper, wireless network simulator is implemented using the C++ object-oriented programming language. This simulator can simulate wireless data services, like as ad-hoc networks, by considering the user's mobility. In this paper, the simulator includes network traffic model to reflect wireless data service and traffic source model to represent a user's mobility similar to real service environment and traffic characteristics can be reflected on the simulation, and also more accurate simulation results can be got through that. In addition, by using object-oriented techniques, new service feature or environment can be easily added or changed so that the developed mobile communication simulator can reflect the real service environment all the time. This simulator can be used in adjusting the characteristics of wireless data hosts following the mobility of the user, and also can be used in building new wireless ad-hoc network routing protocols.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.12
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• pp.1361-1366
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• 2015

In Korea, the special seats for vulnerable users such as the elderly and pregnant woman are provided. However, the usage of seats is very low due to the ignoring or lack of recognition about pregnant woman even though pregnant woman approaches the seat. In this paper, we first consider the problem of special seats for pregnant woman and propose the wireless communication based pregnant alarm service which announces approaching of pregnant woman when pregnant woman moves toward the seats for pregnant woman. First, the service concept and scenario are introduced. Then, we deal with wireless communication technologies which provides the alarm service and their properties. In addition, we discuss implementation issues for realizing the proposed system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.10
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• pp.915-924
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• 2012

Though a mobile device is equipped with a number of wireless communication interfaces in general such as Zigbee, Bluetooth, Wi-Fi, 3G, it uses only one interface for a specific service. In this paper, we propose a mechanism of adaptive switching between wireless communication interfaces in order to efficiently use various communication interfaces. Depending on the application service and the characteristics of wireless communication interface, mobile devices select an appropriate wireless communication interface and may switch to another interface during the service. As a result, power consumption can be reduced and the utilization of communication interface can be improved by using this mechanism.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.6
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• pp.2680-2696
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• 2018

The collaborative content caching system is an effective solution developed in recent years to reduce transmission delay and network traffic. In order to decrease the service end-to-end transmission delay for future 5G ultra-dense networks (UDN), this paper proposes a novel service migration method that can guarantee the continuity of service and simultaneously reduce the traffic flow in the network. In this paper, we propose a service migration optimization model that minimizes the cumulative transmission delay within the constraints of quality of service (QoS) guarantee and network condition. Subsequently, we propose an improved firefly algorithm to solve this optimization problem. Simulation results show that compared to traditional collaborative content caching schemes, the proposed algorithm can significantly decrease transmission delay and network traffic flow.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.152-152
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• 2004

• Journal of Korea Multimedia Society
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• v.12 no.10
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• pp.1407-1417
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• 2009

Today is the Information age which Internet service acts a most important Information Source. So the Power Line Communication has been achieved to offer Internet service for Last-Mile area. And Research is achieved to frequence range from 30MHz to 80MHz for High-speed communication service. But, Power Line is not suitable for communication, So, electric wave is generated from flow of communication information. And the electric wave is interfered with Wireless Communication Service using the same frequence range. In this paper, a Notch Filter for reduce of interference between Power Line Communication and Wireless Communication Service is proposed. The proposed emulator is developed using TMS320C6416T DSP board of Texas Instruments.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.1
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• pp.89-94
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• 2018

This paper investigated the design method of the smart sensor for implementing IoT (Internet of Things) service. The power supply of sensor consistently acquisting data is based on the energy harvesting technology and designed with piezoelectric transducer not affected by surrounding circumstances. The wireless communication interface for the transmission of data is designed with BLE (Bluetooth Low Energy). BLE is highly adequate wireless communication technology for low power consumption and short distance wireless communication. The main application of BLE is beacon whose usage range is extended from O2O (Online to Offline) service, navigator based on indoor positioning technology, and anti-theft/lost child prevention service to mobile game. This paper studied the method to extend wireless coverage for complementing the short wireless transmission distance of BLE. The wireless sensor network based on CATV network is proposed for the easy construction of BLE sensor network and extended wireless coverage.

• Journal of Information Technology Services
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• v.7 no.3
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• pp.215-237
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• 2008

As the paradigm of communications changes from technology-centered service provision to human-centric services, the future wireless communication systems is expected to be able to provide user-centric customized and optimized services. In order to cope with such paradigm shift in communications, various research activities on next generation mobile communication systems are being carried by a number of international organization and research centers to take initiative in future ubiquitous wireless communication environment. In this paper we propose a generic research and development framework consisting of four different research and development phases, a vision and strategy establishment phase, a service development phase, a service reference model creation phase and future service foresight phase. In particular, we give prospect of future ubiquitous wireless communication services covering different service areas of future life style based on our research frameworks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.4068-4086
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• 2014

Due to the prevalence of powerful mobile terminals and the rapid advancements in wireless communication technologies, the wireless video streaming service has become increasingly more popular. Recent studies show that video streaming services via Transmission Control Protocol (TCP) are becoming more practical. TCP has more advantages than User Diagram Protocol (UDP), including firewall traversal, bandwidth fairness, and reliability. However, each video service shares an equal portion of the limited bandwidth because of the fair sharing characteristics inherent in TCP and this bandwidth fair sharing cannot always guarantee the video quality for each user. To solve this challenging problem, an Adaptive Multiple TCP (AM-TCP) scheme is proposed in this paper to guarantee the video quality for mobile devices in wireless networks. AM-TCP adaptively controls the number of TCP connections according to the video Rate Distortion (RD) characteristics of each stream and network status. The proposed scheme can minimize the total distortion of all participating video streams and maximize the service quality by guaranteeing the quality of each video streaming session. The simulation results show that the proposed scheme can significantly improve the quality of video streaming in wireless networks.