• Title/Summary/Keyword: LTE-R

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Handover Performance Improvement for LTE-R Network (LTE-R 네트워크에서 핸드오버 성능 개선)

  • Kim, Young-Dong
    • The Journal of the Korea institute of electronic communication sciences
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    • v.15 no.6
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    • pp.1017-1022
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    • 2020
  • LTE-R(Long Term Evolution-Railway) for high speed railway system operation as an essential technology is based on LTE. Recently, moving speed of high speed train is on going to 600[km/h] level over commercial speed 400[㎞/h]. LTE-R as communication technology for a high speed railway system can be able to provide seamless communication to support moving speed for high speed railway system. In this study, a handover method based on prediction is suggested and performance of the suggested method is evaluated. Computer simulation based on NS(Network Simulator)-3 is used for this study.

Handover Performance of LTE-R Networks (LTE-R 네트워크에서 핸드오버 성능)

  • Kim, Young-Dong
    • The Journal of the Korea institute of electronic communication sciences
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    • v.13 no.6
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    • pp.1223-1228
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    • 2018
  • LTE-R(Long Term Evolution - Railway), as a mobile communication technology to support safety operation of train on high speed railway system, have to be equipped appropriately by hand-over method for high moving environment of train. In this paper, hand-over performance of LTE-R network, which is used in railway communication system, is analyzed and hand-over implementation condition is suggested with this analysis. The performance analysis of this study is carried out with computer simulation with NS(Network Simulator)-3. SINR(Signal to Interference and Noise Ratio) and RSRP(Reference Signal Received Power), and Data Rate is used for hand-over performance parameter.

Optimization of LTE-R Network using 2.6GHz Test Frequency in Daebul Test Line (2.6GHz 시험주파수를 이용한 대불선 시험선에서의 LTE-R 망 최적화)

  • KWAK, Woo-Hyun;KIM, Yong-Kyu
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.9
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    • pp.1398-1405
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    • 2015
  • Domestic railway communication in Korea has been introduced for mutual communications among control center, operation staffs, and maintenance staffs. It has been mainly used as railway disaster and safety functions from VHF and UHF from 1980’s and TRS-Astro and TRS-Tetra from the 2000’s. Recently for urban railways communications, 18GHz and 2.4GHz ranges have been utilized for image transmissions and control command communications, respectively. This paper analyzes technical development of LTE-R, LTE communication for Railways, that has been designed as a single integrated railway wireless network in order to merge the current various communication systems. In this paper, we present the details of the examination of the LTE-R test-bed using 2.6GHz test frequency in Daebul test line through CW test and optimization test.

Analysis on Applicability of LTE-R in Urban Railway Tunnel Environment (LTE-R의 도시철도 터널 환경 적용성 분석)

  • Kwak, Woo-Hyun;Lee, Kwang-Hee;Kim, Yong-Kyu;Choi, June-Young
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.12
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    • pp.1796-1803
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    • 2015
  • Unlike commercial LTE network, LTE-R railway network is arranged along a railroad track and the base stations of the network (RUs) are also installed on the waysides. For urban railway systems that are composed of underground tunnels, the leakage coaxial cables are widely used due to the radio propagation characteristics in tunnels. In theory, the tunnel sections are interpreted as the waveguide with blank spaces and for this reason, the tunnel sections are expected to be better than open ground sections in terms of the radio propagation characteristics. In this paper, we analyze the radio propagation characteristics based on this theory by replacing the leakage coaxial cables in the network with Yagi antennas. The test has been carried out in the 2.2km tunnel in the Daebul test track of KORAIL with 2.6GHz LTE-R Network. The LTE-R applicability in urban railways has been tested through the analysis on the radio propagation characteristics with the unmanned train operation system in Daebul tunnel.

Network Evolution Stages and Characteristics of LTE/LTE-Advanced Systems (LTE/LTE-Advanced 네트워크 발전단계 및 특성 - Network and Protocol Architectures)

  • Kim, Jeong-Ho
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.49 no.6
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    • pp.71-76
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    • 2012
  • Recently, the huge growth of mobile data traffic has driven the earlier commercialization of LTE network and the evolution of LTE-Adv has been accelerated because of this trend of mobile traffic surges. Thus it has enabled the global connectivity and roaming capability due to continual standardization activities. The 3rd generation mobile communication system has been improved through incorporating technologies of HSDPA, MBMS and HSUPA etc continuously. Also, OFDMA/SC-FDMA-based LTE standardization has been under way. In this paper, the architectures of LTE network and protocol have been introduced and their inherent operation mechanisms have also been explored in order to give some insights about the LTE/LTE-Adv networks while their architectures are considered as most prominent candidate for worldwide standard by ITU-R and mobile operators for international communication networks.

A Study on Slow Driving of Metropolitan Train for Disorder Condition of Platform Safety Gate using LTE-R and Beacon (LTE-R과 비콘을 활용한 승강장안전문 장애발생 시 열차 서행운전에 관한 연구)

  • Joh, Eungyoung;Noh, Jowon;Kim, Jin-Tea;Lee, Sunghwa
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.20 no.3
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    • pp.31-36
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    • 2020
  • The LTE-R system is a system consisting of a packet network that provides all IP-based services. Continuous failures related to the platform safety gate and subsequent safety accidents related to passengers and safety gate workers continue. The secondary damage caused by the failure of the platform safety door and the related human life damage have emerged as a major social issue.. By linking the beacon system to the Long Term Evoluton-Railway (LTE-R) network, an LTE-based railway wireless network currently in operation or being installed, it precisely locates trains and provides standardized fault alerts to train crews. When entering into the station, ultimately we will decelerate the train and reduce the accidents of metropolitabn railroad traffic by securing safe driving.

ICT기반의 철도무선망의 진화: LTE 기반 철도무선망의 QoS 관리 중심으로

  • Song, Yong-Su;Kim, Ju-Yeop;Choe, Sang-Won;Kim, Yong-Gyu
    • Information and Communications Magazine
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    • v.32 no.12
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    • pp.3-9
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    • 2015
  • 무선통신에 대한 기술이 급격하게 진화함에 따라, 철도 무선통신도 VHF나 TETRA에서 GSM으로 진보되었고, 현재는 LTE 기반으로 변화하고 있다. 이런 흐름 속에서, 본 고에서는, LTE 로 발전 되는 철도 무선망을 QoS(Quality Of Service) 관리 및 이동통신망 과는 다른 관점에서 철도통신(LTE-Railway)에서 추가되어야 할 요구사항 및 거기에 다른 요소 기술들을 살펴본다. LTE-R 시스템에서는 음성, 영상, 열차제어 등 모든 종류의 진보된 철도 서비스에 대해서 통합된 형태로 안정적이고 신뢰성 있은 서비스를 제공하는 것을 목적으로 한다. 이런 요구사항을 만족시키기 위해서는 일반 이동통신망과는 다른 접근으로 LTE-R을 개발할 필요가 있다. 본 고에서는 LTE 기반 철도통신망과 이동통신망의 다른 요구사항을 기반으로 과 차이점을 QoS(Quality Of Service) 등 철도와 같은 특수 임무형 통신 시스템에서의 요구사항이 적절하고 실용적인지 여부의 검증을 LTE 테스트베드를 실제 철도 영업선 상에 구축을 하고 필드 테스트를 통해서 만족 여부를 검토하였다. 국가적으로 진행되고 있는 LTE 기반 철도 통신망 구축 사업에서 요구하는 통신 기술 사이의 상관관계를 따져봄으로써 LTE-R에서 지원하는 통신 기술이 신뢰도 및 효율성 측면에서 충분한 정도의 기술적인 완성도를 갖추고 있음을 보인다.

Transmission Performance of Application Traffics on High Speed Railway Communications (고속철도통신에서 응용 트래픽의 전송성능)

  • Kim, Young-Dong
    • The Journal of the Korea institute of electronic communication sciences
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    • v.12 no.5
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    • pp.771-776
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    • 2017
  • LTE-R mobile communication technology based on LTE is used to supply various signal and exchange information required for safety operation of train on high speed railway communication system. In this paper, transmission performance of application traffic which is transferred on high speed communication based on LTE-R is analyzed. And some suggestions for application traffic transmission of high speed railway communication will be considered. Computer simulation is used to analyze performance of CBR, VBR as application traffic. Throughput, delay and packet loss rate is used as performance measurement and analysis parameters.

Analysis on Radio Communication Characteristics of LTE Railway Network (철도통합무선망(LTE-R)의 무선통신특성 분석)

  • Yoon, Byungsik;Lee, Sook-Jin;Kim, Dong Joon;Sung, Dong Il
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.9
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    • pp.1-8
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    • 2020
  • The Ministry of Land, Infrastructure and Transport of Korea has been trying to spread integrated railway communication network technologies based on a major railway policy since 2012. As a result, the world's first commercial Long-Term Evolution - Railway (LTE-R) network was established on the Gangneung line (Manjong station - Gangneung station) and has been commercially operating as a railway communication system since 2017. Special function and performance requirements are needed for safe and efficient railway operations, such as group calls, emergency calls, functional addressing, and train control based on wireless communications. In this paper, we present functional and performance railway communications requirements that are based on European wireless railway communications systems. In addition, we measured communications characteristics and performance using a KTX field test on the Gangneung line to analyze the validity and reliability of the LTE-R network. Although the average Radio Frequency (RF) conditions were satisfied in the requirements, we found sudden communications quality degradation, such as Radio Link Failure (RLF) in some railway sections. We propose a way to improve performance and network installations based on in-depth analysis of LTE-R communications field-test results.

An Integrated E-model Implementation for Speech Quality Measurement in VoIP and VoLTE (VoIP와 VoLTE 음성 품질 측정을 위한 통합 E-model 구현)

  • Kim, Bog-Soon;Baek, Kwang-Hyun;Cho, Gi-Hwan
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.7
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    • pp.10-18
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    • 2013
  • With advancing of mobile communication services and commercializing of VoLTE (Voice of LTE), it is getting to pay attention on QoS of VoLTE. This paper proposes an integrated E-model in which some factors influenced to service quality of VoIP and VoLTE based voice communication system are considered in calculating the voice quality of Wideband Codec. The model aims to calculate R value which reflects the situations of access network, network characteristics, terminals' usage and mobility. We mainly deal with the integrated E-model's structure, related algorithms and optimal parameters for VoLTE. Some experiments show that the voice quality difference between VoIP and VoiceChecker, and VoLTE and POLQA, is below 10%. With the proposed model, we can calculate the voice quality by making use of the factors directly affected to service quality and the environment of VoLTE terminal and network. As a result, we can estimate the service quality in advance, without measuring it in real wireless environment.