• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.1
• /
• pp.51-57
• /
• 2016

This paper describes the physical layer modem structure of Giga KOREA 5G system which is being developed by ETRI as a 5G telecommunications prototype. The objective of Giga KOREA 5G system is supporting maximum 100 Gbps data rate for each cell with wide-bandwidth baseband station and mobile station prototypes in mmWave (10~40 GHz) environment. To achieve this objective, its physical layer is composed of high performance baseband station as well as mobile station and their OFDM TDD modems. The important features of Giga KOREA 5G physical layer are carrier aggregation, multiple receiving beam searching in mobile station, high data rate channel encoder and decoder and high speed modulation and demodulation functions.

• ETRI Journal
• /
• v.40 no.1
• /
• pp.10-25
• /
• 2018

The 5GCHAMPION Europe-Korea collaborative project provides the first fully-integrated and operational 5G prototype in 2018, in conjunction with the 2018 PyeongChang Winter Olympic Games. The corresponding technological advances comprise both an evolution and optimization of existing technological solutions and disruptive new features, which substantially outpace previous generations of technology. In this article, we focus on a subset of three disruptive technological solutions developed and experimented on by 5GCHAMPION during the 2018 PyeongChang Olympic Games: high speed communications, direct satellite-user equipment communications, and post-sale evolution of wireless equipment through software reconfiguration. Evaluating effectiveness and performing trials for these key 5G features permit us to learn about the actual maturity of 5G technology prototyping and the potential of new 5G services for vertical markets and end user enhanced experience two years before the launch of large-scale 5G services.

• Electronics and Telecommunications Trends
• /
• v.27 no.5
• /
• pp.95-108
• /
• 2012

Giga KOREA 사업은 IT 산업 활용도를 획기적으로 높여 국가 산업발전을 선도하고, 평생 지식서비스 제공 및 디지털 빈부격차 해소를 통해 국민 복지를 증대시키며, IT 인프라에 의한 위상 재확인을 위해 핵심 기술, 연계 기술개발 및 상용화 기술 리더십을 세워나가기 위한 IT 혁신 사업이다. 본고에서는 관련 정책 동향, 시장 동향, 기술 동향을 살펴본 후, Giga KOREA가 추진하는 연구 내용을 소개한다.

• ETRI Journal
• /
• v.40 no.1
• /
• pp.39-50
• /
• 2018

More people prefer using rail traffic for travel or for commuting owing to its convenience and flexibility. The railway scenario has become an important communication scenario in the fifth generation era. The communication system should be designed to support high-data-rate demands with seamless connectivity at a high mobility. In this paper, the channel characteristics are studied and modeled for the railway tunnel scenario with straight and curved route shapes. On the basis of measurements using the "Mobile Hotspot Network" system, a three-dimensional ray tracer (RT) is calibrated and validated for the target scenarios. More channel characteristics are explored via RT simulations at 25.25 GHz with a 500-MHz bandwidth. The key channel parameters are extracted, provided, and incorporated into a 3rd-Generation-Partnership-Project-like stochastic channel generator. The necessary channel information can be practically realized, which can support the link-level and system-level design of the communication system in similar scenarios.

• ETRI Journal
• /
• v.38 no.2
• /
• pp.280-290
• /
• 2016

To implement high-order multiuser multiple input and multiple output (MU-MIMO) for massive MIMO systems, there must be a feedback scheme that can warrant its performance with a limited signaling overhead. The interference-to-noise ratio can be a basis for a novel form of Codebook (CB)-based MU-MIMO feedback scheme. The objective of this paper is to verify such a scheme's performance under a practical system configuration with a 3D channel model in various radio environments. We evaluate the performance of various CB-based feedback schemes with different types of overhead reduction approaches, providing an experimental ground with which to optimize a CB-based MU-MIMO feedback scheme while identifying the design constraints for a massive MIMO system.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.15 no.1
• /
• pp.42-46
• /
• 1982

Followings are the results of growth of Pacific oysters transplanted from the temperate waters of Korea in February 1981, and cultivated upto early July in the tropical waters of Ambong Bay in Malaysia: The shell length increased from 5.78 mm in February to 25.01 mm in July, and the shell height increased from 7.33 mm in february to 38.91mm in July. The meat weight progressively increased and reached the maximum value of 1.66g in May, but then gradually decreased until July, and the fatness varied from $28\%$ of maximum in March to $11\%$ of minimum in July-Survival rate was $47\%\;and\;39\%$ of the initial number in June and July respectively.

• The Korean Journal of Malacology
• /
• v.15 no.1
• /
• pp.41-47
• /
• 1999

From September 1994 to April 1996, we observed the suspending time dependant meat increase (dry weight) for oysters at Pukman Bay in Korea. The oysters which suspended in September increased to 5 g in meat weight (dry weight) by January. Ones in June increased rapidly but lessened during summer and this stagnation of meat increase extended to autumn. It took long time to compensate for the loss of meat weight owing to spawning. Oysters suspended in July or August showed low growth or stagnation due to the high water temperature and spawning activities after suspending. However, meat weight showed sudden increasement after December and achieved 5 g at the late farm period. The meat increase of oysters suspended in October or November was very slow during entire growing period. Most of them did not achieved 5 g during farm period. The negative correlation was observed between meat growth and water temperature in September. Also, there was a high correlation between meat growth and chlorophyll-a. It was believed that deficiency of food organisms in the water column lead slow growth in terms of meat growth, particularly right after transplanting seed oysters to the farm. Our study suggests that proper time for transplanting oysters is between August and mid-September. However, the data indicate that good growth of oysters is depending upon amount of food available in the water column.

• Analytical Science and Technology
• /
• v.22 no.5
• /
• pp.360-368
• /
• 2009

Tributyltin (TBT) use has been prohibited by the IMO (International Maritime Organization), as well as Korea, since 2003. This prohibition has affected a gradual reduction in TBT use in maritime environs (seawater, sediment, and biosamples) in several countries. In this study, Crassostrea gigas (oyster) and Tapes philippinarum (manila clam) were chosen and measured for butyltin compound concentrations to verify TBT pollution levels since its 2003 ban. Specimens were taken directly from farms for concentration measurement, where Crassostrea gigas and Tapes philippinarum are cultivated, as well as prevalent locations predicted to have been polluted. Concentrations of MBT, DBT, and TBT of Crassostrea gigas were measured to be N.D -N.D., N.D. -N.D., and N.D. -60.21 ng Sn $g^{-1}$ (wet wt), respectively. Regarding Tapes philippinarum, MBT, DBT, and TBT were N.D. -12.27 ng Sn $g^{-1}$ (wet wt), N.D. -45.95 ng Sn $g^{-1}$ (wet wt), and N.D.-7.30 ng Sn $g^{-1}$ (wet wt), respectively. For this research, a correlative study was conducted to determine butyltin compound concentration in Crassostrea gigas at the locations where measurements were made in 1994 to determine to what extent TBT pollution level decreased. A decrease in all 7 sites was observed. In 4 of the 7 samples, butyltin compounds were measured to be below the detection limit, while that of the Tapes philippinarum did not appear high compared to foreign research data.

• Journal of fish pathology
• /
• v.22 no.1
• /
• pp.35-44
• /
• 2009

The potential pathogenicity of Vibrio splendidus biovar II, which was isolated from triploid larvae of pacific oyster with bacillary necrosis and fish pathogenic V. anguillarum were investigated. The 5-day-old larvae infected with V. splendidus biovar II at the dose of $1.81{\times}10^{4}$ CFU/$m\ell$ started to die within 8 hours after exposure and the mortality were reached to 100% in 16 hours. However, $1.13{\times}10^{4-5}$ CFU/$m\ell$ of V. anguillarum caused 5.5-20% mortality of the larvae after 24 hours. The 10-day-old larvae infected with V. splendidus biovar II at the dose of $5.0{\times}10^{5}$ CFU/$m\ell$ showed mortality from 8 hours after challenge and led to a marked mortality of 90.47% after 24 hours. But V. anguillarum at doses of $5.08{\times}10^{3-6}$ CFU/$m\ell$ did not show mortality in the 10-day-old larvae. Therefore V. splendidus biovar II exhibited stronger virulence in 5-day-old larvae than 10-day-old and young oyster. Changes in the concentration of Vibrio in sea water showed that V. anguillarum decreased from $1.13{\times}10^{5}$ CFU/$m\ell$ to 1.7${\times}$105 CFU/$m\ell$ and V. splendidus biovar II increased from $1.81{\times}10^{4}$ CFU/$m\ell$ to $1.7{\times}10^{7}$ CFU/$m\ell$. This strong survival ability of V. splendidus biovar II in seawater was thought as one of the virulence factors against oyster larvae. The mortalities of 5-day-old and 10-day-old oyster larvae were decreased by addition of 30 $\mu{g}/m\ell$ of antibacterial agent(oxytetracycline or streptomycin). These results suggest that bacillary necrosis by V. splendidus biovar II can be occurred in oyster larvae in Korea. And virulence of V. splendidus biovar II is stronger than that of V. anguillarum in oyster larvae causing significant mortality at the density of $10^{4}$ CFU/$m\ell$.