• Title/Summary/Keyword: Terrestrial System

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Design and Implementation of Transmission Scheduler for Terrestrial UHD Contents (지상파 UHD 콘텐츠 전송 스케줄러 설계 및 구현)

  • Paik, Jong-Ho;Seo, Minjae;Yu, Kyung-A
    • Journal of Broadcast Engineering
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    • v.24 no.1
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    • pp.118-131
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    • 2019
  • In order to provide 8K UHD contents of terrestrial broadcasting with a large capacity, the terrestrial broadcasting system has various problems such as limited bandwidth and so on. To solve these problems, UHD contents transmission technology has been actively studied, and an 8K UHD broadcasting system using terrestrial broadcasting network and communication network has been proposed. The proposed technique is to solve the limited bandwidth problem of terrestrial broadcasting network by segmenting 8K UHD contents and transmitting them to heterogeneous networks through hierarchical separation. Through the terrestrial broadcasting network, the base layer corresponding to FHD and the additional enhancement layer data for 4K UHD are transmitted, and the additional enhancement layer data corresponding to 8K UHD is transmitted through the communication network. When 8K UHD contents are provided in such a way, user can receive up to 4K UHD broadcasting by terrestrial channels, and also can receive up to 8K UHD additional communication networks. However, in order to transmit the 4K UHD contents within the allocated bit rate of the domestic terrestrial UHD broadcasting, the compression rate is increased, so a certain level of image deterioration occurs inevitably. Due to the nature of UHD contents, video quality should be considered as a top priority over other factors, so that video quality should be guaranteed even within a limited bit rate. This requires packet scheduling of content generators in the broadcasting system. Since the multiplexer sends out the packets received from the content generator in order, it is very important to make the transmission time and the transmission rate of the process from the content generator to the multiplexer constant and accurate. Therefore, we propose a variable transmission scheduler between the content generator and the multiplexer to guarantee the image quality of a certain level of UHD contents in this paper.

Next Generation Terrestrial DTV Transmission Technology (차세대 지상파 DTV 전송기술)

  • Kim, Sung-Hoon;Choi, Jin-Soo;Hong, Jin-Woo
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.9-11
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    • 2008
  • In this paper, we describe a 1/4 rate robust modulation algorithm for Enhanced-xVSB system which is fully backward compatible with ATSC 8-VSB standard. Laboratory test results of proposed Enhanced-xVSB 1/4 rate mode is shown a significantly improved reception performance under multipath as well as AWGN channel. We suggest an Enhanced-xVSB terrestrial broadcasting system for in-band Pedestrian/Portable TV broadcasting service.

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Research on the data rate increasing technique for terrestrial mobile multimedia broadcasting (지상파 이동멀티미디어 방송의 전송률 개선기법 연구)

  • Bae, Jae-Hwui;Lim, Hyoung-Soo;Lim, Jong-Soo;Lee, Soo-In;Han, Dong-Seok
    • Proceedings of the IEEK Conference
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    • 2006.06a
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    • pp.109-110
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    • 2006
  • We propose a data rate increasing technique for T-DMB (terrestrial digital multimedia broadcasting) system. With the application of hierarchical modulation, it is possible to increase data rate and improve services. We conducted the performance analysis of the proposed hierarchical modulation in AWGN channel and showed the BER analysis. The simulation results show that the proposed method shows possibilities to increase the data rate with a moderate degradation of the existing system.

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Numerical Study on the Link Range of the IM/DD Wireless Optical Communication at 830[nm] Optical Wavelength using Galilean Optics (갈릴리안 광학계를 사용한 IM/DD 광무선통신 시스템에서 830[nm] 광파장에 대한 전송거리 제한 해석)

  • Hong, Kwon-Eui;Ko, Sung-Won;Cho, Jung-Whan
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.11
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    • pp.123-129
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    • 2011
  • In terrestrial wireless optical communication links, atmospheric effects including turbulence, absorption and scattering have significant impact on the system performance. Based on the analysis of transmission in atmospheric channel concerning 830[nm] wavelength diode laser beam, performance of free space optical (FSO) link utilizing Galilean optics as a laser beam transmitting and receving optics, PIN photodiode as a detecting device. In this paper we designed optical link equation for received optical power and we analyze the atmospheric effects on the signal to noise ratio (SNR) and bit error rate (BER) of an terrestrial FSO system. We show that the possible communication distance for BER=$10^{-9}$ in proposed adverse atmospheric conditions.

DLMS SCADA System based on TETRA (TETRA 기반 DLMS 원방감시 시스템)

  • Song, Byung-Kwen;Lee, Suk-Hee
    • Journal of IKEEE
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    • v.13 no.3
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    • pp.95-102
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    • 2009
  • TETRA(TErrestrial Trunked RAdio) is wireless communication system generally adopted to public network and backbone network, as the technology of Trunked Radio System specified by ETSI(European Telecommunications Standards Institute) and currently adopted to the Electric Power IT Backbone Network in Korea. DLMS(Device Language Message Specification) is used in order to meter an electric measuring instrument value. In this paper, DLMS Server and Client simulator are used based on Window operating system. The multi-functional gateway, which transforms the communications based on RS-232C between DLMS Server Simulator and Client Simulator to the one based on TETRA PEI(Peripheral Equipment Interface), is developed such that DLMS SCADA(Supervisory Control And Data Acquisition) system is constructed based on TETRA.

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eLoran Signal Standard Inspection Process Development

  • Son, Pyo-Woong;Seo, Kiyeol;Fang, Tae Hyun
    • Journal of Positioning, Navigation, and Timing
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    • v.10 no.2
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    • pp.153-158
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    • 2021
  • In order to mitigate the vulnerability of the satellite navigation system against radio frequency interference, South Korea has been developing advanced terrestrial navigation system (eLoran) technology since 2016. The eLoran system synchronizes the transmission time of the pulse used in the existing Loran-C system with UTC and transmits correction information that can improve the position error. The eLoran system is known to reduce the position error of about 460 m of the existing Loran-C system to 20 m, and for this, the transmitter must be able to transmit eLoran signals according to more stringent standards. For this reason, an international standard that further developed the Loran-C signal standard established by US Coast Guard was established by Society of Automotive Engineers (SAE) International. In this paper, based on the analysis of the SAE9990 document, the international standard for eLoran transmission signals, a standard inspection process was produced to check whether the eLoran transmitter is transmitting signals in accordance with the standard.

Development of Cross Section Management System in Tunnel using Terrestrial Laser Scanning Data (지상 레이저 스캐닝 자료를 이용한 터널단면관리시스템 개발)

  • Roh, Tae-Ho;Kim, Jin-Soo;Lee, Young-Do
    • Journal of the Korean Association of Geographic Information Studies
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    • v.11 no.1
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    • pp.90-104
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    • 2008
  • Laser scanning technology with high positional accuracy and high density will be widely applied to vast range of fields including geomatics. Especially, the development of laser scanning technology enabling long range information extraction is increasing its full use in civil engineering. This study taps into the strengths of a terrestrial laser scanning technique to develop a tunnel cross section management system that can be practically employed for determining the cross section of tunnels more promptly and accurately. Three dimensional data with high density were obtained in a prompt and accurate manner using a terrestrial laser scanner. Data processing was then conducted to promptly determine arbitrary cross sections at 0.1meter, 0.5meter and 1.0meter intervals. A laser scanning technique was also used to quickly and accurately calculate the overbreak and underbreak of both each cross section and the entire tunnel section. As the developed system utilizes vast amounts of data, it was possible to promptly determine the shape of arbitrary cross section and to calculate the overbreak and underbreak more accurately with higher area precision. It is expected, therefore, that the system will not only enable more efficient and cost effective tunnel drilling management and monitoring but also will provide a basis for future construction and management of tunnel cross section.

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Transmission Signal Normalization Scheme for Advanced Terrestrial Digital Multimedia Broadcasting (AT-DMB 전송 신호 정규화 방안)

  • Lee, Sang-Woon;Kim, Young-Su;Yun, Jeong-Song
    • Journal of Broadcast Engineering
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    • v.15 no.6
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    • pp.868-875
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    • 2010
  • AT-DMB was developed to raise the transmission rate of existing T-DMB with backward compatability. The transmission and hierarchical video service technique were legislated as Korean TTA standards, and other application service techniques including data services are being developed for the commercial service. In this paper, we consider the power of transmission power level of signals in Advanced Terrestrial Digital Multimedia System according to the constellation ratio. And we propose a new scheme for normalization of transmission signal power level in AT-DMB system. Adopting this scheme, the signal power level of hierarchical modulated signal can be uniform in AT-DMB system both for B Mode and Q Mode.

A Modification of ATSC Transmission System for Terrestial 3D HDTV Broadcasting (지상파 3D HDTV 전송을 위한 ATSC 전송 시스템의 확장 및 수정에 관한 연구)

  • Oh, Jong-Gyu;Kim, Joon-Tae
    • Journal of Broadcast Engineering
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    • v.15 no.5
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    • pp.681-696
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    • 2010
  • In this paper, we examined the possibility of the transmission capacity increase by an extension and a modification of ATSC 8-VSB transmission system[1] for broadcasting a 3D HDTV services through 6 MHz terrestrial channel. First we examined the performance and the limit of conventional ATSC 8-VSB transmission system. After that LDPC & BCH code are employed instead of conventional RS & TCM code and the transmission parameter is founded for the capacity increase with resonable TOV by varying the code-rates and increasing the modulation constellation. We do not consider the perfect backward compatibility for maximum transmission capacity increase like DVB-S2 system.

Design and Implementation of Assisted GPS Navigation Systems Using TPEG Protocol of Terrestrial DMB Data Services (지상파 DMB 데이터 서비스의 TPEG프로토콜을 이용한 Assisted GPS 항법 시스템의 설계 및 구현)

  • Kim, Byung-Soo;Min, Seung-Wook
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.11B
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    • pp.1618-1623
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    • 2010
  • In this paper, we propose a new assisted global positioning system (A-GPS) using terrestrial digital multimedia broadcasting (T-DMB) data services. Because of the weak signal strength from GPS satellite and the signal blockage, it is difficult for the telematics terminal to determine the position in urban area. Proposed A-GPS system calculates pseudo range (PR) from timing information of GPS satellites and obtains the satellite information such as ephemeris from T-DMB station to determine the current position. Compared to conventional GPS system, the proposed system has better performance in terms of the fast time to first fix (TTFF), low horizontal dilution of precision (HDOP). Experimental results show that the proposed system is a feasible and robust solution.