• Title, Summary, Keyword: Mobile Communications

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Mobile Communications System and Its Development Vision (이동통신 시스템과 개발 비전(I))

  • 조규심
    • Journal of the Korean Professional Engineers Association
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    • v.31 no.1
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    • pp.9-16
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    • 1998
  • For the flow facing high1y informationized age, there is a flow from fixed communications connecting fixed places such as offices and homes to mobile communications connecting mobile objets such as automobiles, ships and aircraft. This flow has added to diversifying communications Including data and images. While the axed mode is diversifying information media by digitalization of communications network and computers, the mobile mode has brought higher sophistication of communication modes by a higher degree of electric wave utilization. The following descriptions outlines the mobile communication which is utilizing the electric wave phenomena. In sequence the following items are described: a brief history of mobile communications, the technical object and various kinds of services, propagation of electric wave signal.

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Mobile Communications System and It's Development Vision(II) (이동통신 시스템과 개발 비전(II))

  • 조규심
    • Journal of the Korean Professional Engineers Association
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    • v.31 no.2
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    • pp.65-72
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    • 1998
  • For the flow facing highly informationized age, there Is a flow from fixed communications connecting fixed places such as offices and homes to mobile communications connecting mobile objets such as automobiles, ships and aircraft. This flow has added to diversifying communications including data and images. While the fixed mode Is diversifying information media by digitalization of communications network and computers, the mobile mode has brought higher sophistication of communication modes by a higher degree of electric wave utilization. The following descriptions outlines the mobile communication which Is utilizing the electric wave phenomena. In sequence the following items are described: a brief history of mobile communications, the technical object and various kinds of services, propagation of electric wave signal.

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An Analysis of the 4G Mobile Communications Technology Development Strategy in Korea (4세대이동통신 기술개발전략 분석)

  • 노일수;엄기용;유영신;이병남
    • Proceedings of the Technology Innovation Conference
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    • pp.257-268
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    • 2002
  • Korean mobile communications industry has been a main locomotive of the drastic development of Korean IT industry and became one of core industries in national economy. To secure strong competitiveness of mobile communications industry, smooth cooperation should be reconsidered among government, universities, research institutions, and private companies. Future mobile communications technology will be evolved from IMT-2000 to system upgrade, 3.5G and 4G. And the goals of technology development are provision of mobile multimedia services based on better mobility and higher data speed rates. Therefore, Korea's technology development strategies of mobile communications should be focused on intensifying bondage of international cooperation, strengthening standardization activities, and enhancing core technology development capability to secure IPR.

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Demonstration of Mobile Fronthaul Test Bed Based on RoF Technology Supporting Two Frequency Assignments and 2 × 2 MIMO Antennas

  • Cho, Seung-Hyun;Han, Changyo;Chung, Hwan Seok;Lee, Jong Hyun
    • ETRI Journal
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    • v.37 no.6
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    • pp.1055-1064
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    • 2015
  • We demonstrate a next-generation high-capacity mobile fronthaul based on radio over fiber (RoF) technology, which links between a digital unit and a radio unit supporting two frequency assignments and $2{\times}2$ multiple input, multiple output antennas. To confirm the technical feasibility of a mobile fronthaul, we experimentally investigate its down- and uplink end-to-end performances including the optical and radio frequency (RF) signal path. Frequency-dependent performance deviations, error vector magnitude variations, overall system performance variations caused by optical to electrical conversion, and intermediate frequency to RF conversions are examined. Experimental verifications on multiple LTE uplink signals are performed for the first time. We also demonstrate several commercial mobile Internet services, YouTube video streaming, and file transfers using off-the-shelf mobile devices, through a mobile fronthaul based on RoF.

Cryptanalysis of an Authenticated Key Agreement Protocol for Wireless Mobile Communications

  • He, Debiao
    • ETRI Journal
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    • v.34 no.3
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    • pp.482-484
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    • 2012
  • With the rapid progress of wireless mobile communications, the authenticated key agreement (AKA) protocol has attracted an increasing amount of attention. However, due to the limitations of bandwidth and storage of the mobile devices, most of the existing AKA protocols are not suitable for wireless mobile communications. Recently, Lo and others presented an efficient AKA protocol based on elliptic curve cryptography and included their protocol in 3GPP2 specifications. However, in this letter, we point out that Lo and others' protocol is vulnerable to an offline password guessing attack. To resist the attack, we also propose an efficient countermeasure.

Converged Mobile Cellular Networks and Wireless Sensor Networks for Machine-to-Machine Communications

  • Shan, Lianhai;Li, Zhenhong;Hu, Honglin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.6 no.1
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    • pp.147-161
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    • 2012
  • In recent years, machine-to-machine (M2M) communications are under rapid development to meet the fast-increasing requirements of multi-type wireless services and applications. In order to satisfy M2M communications requirements, heterogeneous networks convergence appears in many areas, i.e., mobile cellular networks (MCNs) and wireless sensor networks (WSNs) are evolving from heterogeneous to converged. In this paper, we introduce the system architecture and application requirement for converged MCN and WSN, where mobile terminals in MCN are acting as both sensor nodes and gateways for WSN. And then, we discuss the joint optimization of converged networks for M2M communications. Finally, we discuss the technical challenges in the converged process of MCN and WSN.

A Study on Implementation of Roaming Function in Digital Mobile Communications System using a Client-Server Model (클라이언트-서버 모델을 사용한 디지틀 이동통신 시스템의 로우밍 기능 구현에 관한 연구)

  • 임선배;박진우
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.17 no.12
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    • pp.1371-1379
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    • 1992
  • In this paper, we describe the general concept of digital mobile communications system and present a client-server model for the implementation of roaming function, which is on of the most important functions in digital mobile communications system. And finally we also describe our simulation test and analysis for the presented client-server model.

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Implementation of Mobile Internet E-mail & Chatting Program using WIPI Platform

  • Hwang, Byung-Kon
    • Proceedings of the Korea Society of Information Technology Applications Conference
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    • pp.7-12
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    • 2005
  • In this paper, we implemented an e-mail and chat program (client) for communication between mobile devices and PCs based on WIPI a South Korea's open wireless platform form developing device and content independent software to break from the way of developing contents that is dependent on different wireless platforms to each mobile communications company. While traditional e-mail and chat programs are written for PC-to-PC communication, we develop them for mobile-to-PC and mobile-to-mobile communications, and we expect to see various mobile contents in the future.

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Efficient Macro Mobility Management for GPRS IP Networks

  • Choi, Seong-Gon;Mukhtar, Rami;Choi, Jun-Kyun;Zukerman, Moshe
    • Journal of Communications and Networks
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    • v.5 no.1
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    • pp.55-64
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    • 2003
  • Mobile IP has several inefficiencies, and was not originally designed for situations where both peers are highly mobile. We present a mobility management solution that retains compatibility with existing Internet protocols, whilst increasing the efficiency of communications between two GPRS mobile hosts. Our proposal eradicates triangle routing and minimizes handover latency. We show by numerical analysis that the routing optimization improves the performance of TCP controlled data flows, reducing buffering requirements and minimizing the recovery time after a handover occurs.