• Title/Summary/Keyword: mobile radio

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Channel Allocation Using Mobile Mobility and Neural Net Spectrum Hole Prediction in Cellular-Based Wireless Cognitive Radio Networks (셀룰러 기반 무선 인지망에서 모바일 이동성과 신경망 스펙트럼 홀 예측에 의한 채널할당)

  • Lee, Jin-yi
    • Journal of Advanced Navigation Technology
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    • v.21 no.4
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    • pp.347-352
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    • 2017
  • In this paper, we propose a method that reduces mobile user's handover call dropping probability by using cognitive radio technology(CR) in cellular - based wireless cognitive radio networks. The proposed method predicts a cell to visit by Ziv-Lempel algorithm, and then supports mobile user with prediction of spectrum holes based on CR technology when allocated channels are short in the cell. We make neural network predict spectrum hole resources, and make handover calls use the resources before initial calls. Simulation results show CR technology has the capability to reduce mobile user handover call dropping probability in cellular mobile communication networks.

Analysis of Field Strength and Path Loss in Seoul and Daejeon Area (서울 및 대전지역에서의 전계강도와 경로손실 분석)

  • 송기홍;정인명;김종호;양기곤
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.4 no.2
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    • pp.4-10
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    • 1993
  • In mobile radio communication, propagation paths are time or spacial varying because of the motion of mobile unit. The propagation path loss not only involves frequency and distance but also the antenna height at both the base station and the mobile unit, terrain configuration, and the man made en- vironment. Thhese additional factors make the prediction of propagation path loss of mobile radio signals more difficult. In this paper, it is measured field strenght of mobile radio signals in Daejeon and Seoul area, also calculated local median, 500m sample mean, and stadard deviation. As the result of analysis, it can be seen that propagation path loss of measured data is similiar to predicted field strength, especially local median is dependent upon base antenna height, terrain configuration and the man-made environment. The standard deviation has been noted to lie between 2 and 10 dBuV.

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A REID privacy protect scheme based on mobile (모바일 기반의 RFID 프라이버시 보호 기법)

  • Kim, Il-Jung;Choi, Eun-Young;Lee, Dong-Hoon
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.17 no.1
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    • pp.89-96
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    • 2007
  • Radio Frequency Identification system based on EPC(Electronic Product Code) Network Environment can read or write information of tagged objects, using Rf signals without direct contact. This advantage which is to provide storage ability and contactless property is better than Bar-code system. Mobile RFID system which integrates Mobile system with RFID system will provide new additional service to users. However, an advantage for obtaining information of objects using RF signal causes personal privacy problem. In this paper, we propose techniques that can protect personal privacy based on mobile. Our scheme provides privacy protection of users and is more efficiently than another application service.

Wireless Mobile Sensor Networks with Cognitive Radio Based FPGA for Disaster Management

  • Ananthachari, G.A. Preethi
    • Journal of Information Processing Systems
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    • v.17 no.6
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    • pp.1097-1114
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    • 2021
  • The primary objective of this work was to discover a solution for the survival of people in an emergency flood. The geographical information was obtained from remote sensing techniques. Through helpline numbers, people who are in need request support. Although, it cannot be ensured that all the people will acquire the facility. A proper link is required to communicate with people who are at risk in affected areas. Mobile sensor networks with field-programmable gate array (FPGA) self-configurable radios were deployed in damaged areas for communication. Ad-hoc networks do not have a centralized structure. All the mobile nodes deploy a temporary structure and they act as a base station. The mobile nodes are involved in searching the spectrum for channel utilization for better communication. FPGA-based techniques ensure seamless communication for the survivors. Timely help will increase the survival rate. The received signal strength is a vital factor for communication. Cognitive radio ensures channel utilization in an effective manner which results in better signal strength reception. Frequency band selection was carried out with the help of the GRA-MADM method. In this study, an analysis of signal strength for different mobile sensor nodes was performed. FPGA-based implementation showed enhanced outcomes compared to software-based algorithms.

Analysis of SAR for body-mounted mobile phones (인체 착용형 무선 단말기에 대한 노출량 해석)

  • Park, Min-Young;Ko, Chea-Ok;Pack, Jeong-Ki
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2005.11a
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    • pp.425-428
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    • 2005
  • A variety of wireless devices are commercially available now. Most of studies, however, have been directed to the biological effects of mobile-phone EMF. In this study, dosimetric analysis for wireless devices of head-mounted display type and a wristwatch type were made to investigate possible biological effects of these devices. SAR (Specific Absorption Rate) distributions were calculated using FDTD (Finite Difference Time Domain) method, for adult human models such as standard Korean human model and VHP(Visible Human Project) model, as well as scaled models. Measurements were also performed for SAM phantom wearing a simplified prototype for a wireless device for validation of the simulation results. It has been found that children are more vulnerable to such exposure, and these devices could cause some biological effects for relatively lower power compared to conventional mobile pones.

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Error Control Performance of Punctured convolutional Codes for Digital Mobile Radio Channels (이동 무선 통신 채널에 대한 소거식 길쌈부호의 오류제어특성)

  • Lee, Sang-Gon;Moon, Sang-Jae;Kim, Jae-Moung
    • Proceedings of the KIEE Conference
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    • 1987.07b
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    • pp.884-888
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    • 1987
  • Error control performance of punctured convolutional codes is considered in digital mobile radio communication wherein GMSK and DQPSK are assumed to be employed as a modulation scheme. Bit error rates of the two modulation systems with the punctured convolutional code are computed, and compared each other, some good punctured convolutional codes are searched and listed fork practical application to the digital mobile radio communication.

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Design of the Novel DVB-H Antenna for the Folder-Type Mobile Handheld Terminal

  • Lee, Jung-Nam;Park, Jong-Kweon;Kim, Jin-Suk
    • Journal of electromagnetic engineering and science
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    • v.8 no.1
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    • pp.28-33
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    • 2008
  • We have proposed a novel DVB-H(Digital Video Broadcast for Handheld) antenna for folder-type mobile handheld terminal by using a coupling element, a stub, and an L-type matching circuit. The L-type matching circuit consisting of two chip inductors is used for achieving an improved impedance matching over the DVB-H frequency band ($470{\sim}702\;MHz$). Simulated results showed the stub worked to more knot the lower and upper frequency ends of the input impedance curve. The antenna exhibits a flat gain characteristic from 2 to 2.8 dBi over the DVB-H frequency band. The radiation patterns are a stable Figure-of-eight radiation pattern in the frequency range.

Study on Efficient Multi-resource Management Scheme for High-Performance in Multi-Network Environments (멀티네트워크 환경에서 성능 향상을 위한 자원 관리 기술 분석)

  • Youn, Joo-Sang;Park, Youngjae;Pack, Sangheon;Hong, Yong-Geun;Park, Jung-Soo
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.05a
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    • pp.911-914
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    • 2009
  • 멀티 네트워크는 여러 무선 접속 기술을 동시에 접속할 수 있도록 구성된 시스템으로 정의되며 Ambient Networks(ANs) 프로젝트로 연구가 진행 중에 있다. 우선 ANs은 여러 다른 무선 장치와 Multi-Radio Access(MRA) 기술이 군집된 동적 통신 환경에서의 네트워킹 개념이다. 따라서 3 세대로 불리는 Global System for Mobile communications(GSM), Universal Mobile Telecommunications System(UMTS) 그리고 무선랜(WLAN)등 다양한 네트워크 인터페이스로 구성된 mobile terminal(MT)이 다양한 무선 접속 기술을 지원하는 멀티네트워크에 접속하여 "Always Best Connected" 관점에서 효율적 접속 서비스를 제공 받아야 한다. 본 논문에서는 멀티네트워크 환경에서 단말에 high-performance를 제공하기 위한 자원관리 모델인 MRRM/RARM(Multi-Radio/Radio Access Resource Management)과 GLL(Generic Link Layer)에 대한 기술 요소를 정의하고 분석한다.

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Study on Efficient Multi-resource Management Scheme for High-Performance in Multi-Network Environments (멀티네트워크 환경에서 성능 향상을 위한 자원 관리 기술 분석)

  • Youn, Joo-Sang;Park, Youngjae;Pack, Sangheon;Hong, Yong-Geun;Park, Jung-Soo
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.05a
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    • pp.481-484
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    • 2009
  • 멀티 네트워크는 여러 무선 접속 기술을 동시에 접속할 수 있도록 구성된 시스템으로 정의되며 Ambient Networks(ANs) 프로젝트로 연구가 진행 중에 있다. 우선 ANs은 여러 다른 무선 장치와 Multi-Radio Access(MRA) 기술이 군집된 동적 통신 환경에서의 네트워킹 개념이다. 따라서 3 세대로 불리는 Global System for Mobile communications(GSM), Universal Mobile Telecommunications System(UMTS) 그리고 무선랜(WLAN)등 다양한 네트워크 인터페이스로 구성된 mobile terminal(MT)이 다양한 무선 접속 기술을 지원하는 멀티네트워크에 접속하여 "Always Best Connected" 관점에서 효율적 접속 서비스를 제공 받아야 한다. 본 논문에서는 멀티네트워크 환경에서 단말에 high-performance를 제공하기 위한 자원관리 모델인 MRRM/RARM(Multi-Radio/Radio Access Resource Management)과 GLL(Generic Link Layer)에 대한 기술 요소를 정의하고 분석한다.

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A Study of Radio Wave Propagation Criterion for the Cognitive Radio System using Interference Analysis in Broadcasting Band (방송대역에서 간섭분석을 이용한 무선인지 시스템의 전파 전달기준에 관한 연구)

  • Choi, Joo-Pyoung;Duy, Vo Quoc;Lee, Won-Cheol
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.12A
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    • pp.1014-1022
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    • 2009
  • In this paper, interference analysis is carried out to obtain the operating criterion and coexistence condition between digital television devices and cognitive radio-based mobile wimax devices in the UHF (Ultra High Frequency) broadcasting frequency bands. To this end, an efficient interfering calculation tool known as SEAMCAT (Spectrum Engineering Advanced Monte-Carlo Analysis Tool) is employed to acquire the coexistence criterions between heterogeneous radio links operating in the same portion of spectrum. As a result, these criterions will be used to achieve interference temperature limit level applied to interference temperature model for analyzing the capacity of cognitive radio receivers accurately.