• Title/Summary/Keyword: 5G system

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Impact of Channel Estimation Errors on SIC Performance of NOMA in 5G Systems (5G 시스템에서 비직교 다중접속의 SIC 성능에 대한 채널 추정 오류의 영향)

  • Chung, Kyuhyuk
    • Journal of Convergence for Information Technology
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    • v.10 no.9
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    • pp.22-27
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    • 2020
  • In the fifth generation (5G) networks, the mobile services require much faster connections than in the fourth generation (4G) mobile networks. Recently, as one of the promising 5G technologies, non-orthogonal multiple access (NOMA) has been drawing attention. In NOMA, the users share the frequency and time, so that the more users can be served simultaneously. NOMA has several superiorites over orthogonal multiple access (OMA) of long term evolution (LTE), such as higher system capacity and low transmission latency. In this paper, we investigate impact of channel estimation errors on successive interference cancellation (SIC) performance of NOMA. First, the closed-form expression of the bit-error rate (BER) with channel estimation errors is derived, And then the BER with channel estimation errors is compared to that with the perfect channel estimation. In addition, the signal-to-noise (SNR) loss due to channel estimation errors is analyzed.

A Comparison of BER Performance for Receivers of NOMA in 5G Mobile Communication System (5G 이동 통신 시스템에서 비직교 다중접속의 수신기들에 대한 BER 성능의 비교)

  • Chung, Kyuhyuk
    • Journal of Convergence for Information Technology
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    • v.10 no.8
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    • pp.7-14
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    • 2020
  • In the fifth generation (5G) mobile networks, the mobile services require 100 times faster connections. One of the promising 5G technologies is non-orthogonal multiple access (NOMA). In NOMA, the users share the channel resources, so that the more users can be served simultaneously. There are several advantages offered by NOMA, such as higher spectrum efficiency and low transmission latency, compared to orthogonal multiple access (OMA), which is usually used in the fourth generation (4G) mobile networks, for example, long term evolution (LTE). In this paper, we compare the receivers for NOMA. The standard NOMA receiver, the non-SIC NOMA receiver, and the symmetric superposition coding (SC) NOMA receiver are compared. Specifically, it is shown that the performance of the standard receiver is the best, whereas the performances of the non-SIC receiver and symmetric SC receiver are dependent on the power allocation.

Growth of Sex Reversed Nile Tilapia, Oreochromis niloticus In a Closed Recirculating Culture System

  • Yoon Gil Ha;Jo Jae-Yoon;Kim Youhee;Kim In-Bae
    • Fisheries and Aquatic Sciences
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    • v.5 no.1
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    • pp.59-63
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    • 2002
  • Swim up fry of the Nile tilapia, Oreochromis niloticus, were fed 0 or 60 mg l7-methyltestos­terone (MT) per kg feed for 30 days. Fish that had been fed 0 or 60 ppm MT for the first 30 days were subsequently fed a commercial diet for 56 weeks to evaluate growth, survival, sex ratio, body composition, gonadosomatic index and the total edible portion. Mean body weight of MT treated group and untreated group were 1.7 g and 1.1 g, respectively at the end of the treatment for 30 days $(P<0.05)$. The experiment was terminated after a total of 60 weeks, the mean body weight of the MT treated population was 1,016 g and that of the untreated population was 762g $(P<0.05)$. However, the final mean body weight of untreated males (l, 086g) was not significantly different from treated males (l,016 g), but the mean body weight of the female group was 512 g. Therefore, the reason for the lower mean body weight of the untreated group was entirely due to stunted females. The percentage fillet yield of MT treated fish$(34.6\%)$ was not significantly different from that of the untreated males $(34.4\%)$, but the untreated females were lower than those of both treated and untreated male groups $(32.4\%)$ (P<0.05). There were no significant differences in the percentage of the all edible portion (AP) between MT treated and untreated males, but females were lower than males. Females are smaller fish in size and the gonads are larger in proportion which were discarded along with the intestine this explains the observed difference. Total biomass of the two groups were 134.8kg and 104.5kg per $m^3$, respectively. The proportion of fish reaching a marketable size of over 800 g in body weight within 14 months were $78\%$ in the MT treated group and $41\%$ in the untreated group.

Microbiological Safety During Delivering of Food Ingredients Supplied to Elementary School Food Services in Daegu and Gyeongbuk Provinces -Seafood, Meat and Frozen Processing Food- (대구.경북지역 학교 급식에 공급되는 식재료의 유통단계별 미생물 평가 - 어육류, 냉동가공 제품 -)

  • Kim, Yun-Hwa;Ryu, Kyung;Lee, Yeon-Kyung
    • Food Science and Preservation
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    • v.16 no.2
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    • pp.276-285
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    • 2009
  • This study evaluated the microbiological quality and safety of food items(seafood, meat, eggs, and frozen food) supplied to elementary school food services, during delivery, and analyzed the distribution/delivery system. To this end, 10 food items supplied by 13 factories in Daegu and Gyeongbuk were chosen for study. Beef and pork were delivered directly to schools in freezer vans. Seafood, chicken, and frozen food were delivered to schools by refrigerated vans(${\leq}10^{\circ}C$) that made other delivery stops before arriving at schools. After food was delivered to schools, total bacterial counts and coliforms(respectively) were as follows: mackerel($2.0{\times}10^2-3.2{\times}10^5$, $<5-4.0{\times}10^3CFU/g$), common squid($2.5{\times}10^4-6.6{\times}10^5$, $1.6{\times}10^2-6.0{\times}10^3CFU/g$), shellfish($3.2{\times}10^5-1.7{\times}10^3$, $4.0{\times}10^3-3.0{\times}10\;CFU/g$), boiled fish paste($1.9{\times}10^4$, <5 CFU/g), beef($9.2{\times}10^2-6.4{\times}10^4$, $<5-2.0{\times}10\;CFU/g$), pork($2.6{\times}10^3-1.3{\times}10^6$, $<5-2.7{\times}10^2CFU/g$), chicken($1.0{\times}10^4$, $2.4{\times}10^2CFU/g$), egg($<5-2.3{\times}10^2$, <5 CFU/g), frozen mandu($3.2{\times}10^3-9.5{\times}10^4$, <5 CFU/g), and frozen noodles($<5-9.0{\times}10$, <5 CFU/g). Bacillus cereus($2.0{\times}10\;CFU/g$) and E. coli($1.0{\times}10\;CFU/g$) were detected on shellfish, and Staphylococcus aureuswas detected on pork($3.1{\times}10\;CFU/g$) and chicken($7.8{\times}10\;CFU/g$). Most food items were double-wrapped in vinyl and placed in corrugated cardboard boxes prior to delivery, and the boxes weremixed with other food items when they were put in the vans. There was no cross-contamination during distribution. However, total shellfish bacterial counts increased slightly. These results indicate that foods need to be completely pasteurized during processing. Frozen food items should not be mixed and should be delivered by freezer vans(${\leq}4^{\circ}C$). The number of stops made during distribution/delivery should be reduced.

Study on precision improvement in weight measurement of an egg for the automatic egg sorting system (계란(鷄卵) 자동(自動) 선별기(選別機)의 난중측정(卵重測定) 정밀도(精密度) 향상(向上)에 관(關)한 기초연구(基礎硏究))

  • Kim, K.D.;Bok, J.S.
    • Korean Journal of Agricultural Science
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    • v.27 no.1
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    • pp.48-53
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    • 2000
  • The various errors existing in a weight measurement system in most automatic egg sorting system available in Korean poultry farms have caused a large amount of economic losses to the egg producers. The object of this study was an importance of egg measurement system by changing both the number and the arrangements of load cells to reduce measuring errors. The results obtained were summarized as follow : 1. Four arrangements of load cells were selected as follows : layout I : Conventional one load cell method layout II : One load cell located as egg moving direction layout III : Two load cells located facing each other layout IV : Two load cells located as parallel with egg moving direction 2. The results of egg weight measurement according to four arrangements (Layout I, II, III, IV) showed that the average errors were 1.1218g, 0.5953g, 0.7786g, 0.2793g respectively. This indicated that the Layout IV (measuring by 2 load cells located parallel with the egg moving direction) caused the lowest average error and the best in precision. 3. The average vibration of axis X, y, Z were resulted as $5.1937{\times}10^{-3}G$, $9.3604{\times}10^{-3}G$, and $16.8657{\times}10^{-3}G$ respectively when sorting large sized egg. This indicated that the vibration of axis-Z was relatively higher than those of axis-X, and axis-Y.

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Establishment of suspension culture condition for embryogenic callus proliferation and somatic embryo development of Kalopanax septemlobus (음나무 배발생 캘러스의 증식 및 체세포배 발달을 위한 액체 현탁 배양조건 확립)

  • Kim, Sun-Ja;Moon, Heung-Kyu
    • Journal of Plant Biotechnology
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    • v.36 no.1
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    • pp.7-12
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    • 2009
  • This study was conducted to establish the optimal suspension culture system for both the propagation of embryogenic cells (ECs) and the induction of somatic embryos (SEs) of Kalopanax septemlobus. The proliferation rate of ECs was reduced as the inoculum density was increased; the highest rate was obtained when 0.1 g/100 ml of cells was initially inoculated. According to the analysis of cell growth pattern and cell growth cycle (G1, Sand G2/M), the cell growth started in 5 days culture initiation, grew rapidly until 15 days and then decreased gradually. Distinctive changes of the cell growth cycle by the culture periods was also observed; the growth cycle was doubled from initial 5.6% to 11.7% of S stage in 5 days culture and then reached in stable stages again. Therefore, the results indicated that a 15-day-cycle was the optimal culture period for the propagation of the ECs through the suspension culture. Furthermore, the cell inoculum density was also important for the induction of SE; more than 65% of SEs at the torpedo stage was induced by using the low level of cell inoculum (0.5 g/L), while the higher inoculum densities were rapidly reduced the proportion of SEs at that stage. Although the higher inoculum density delayed the development of SE, it did not affect the proportion of SEs at the globular and heart stage. In conclusion, this study showed that the suspension culture of the Kalopanax septemlobus ECs through the control of inoculum density was an efficient way for both the propagation of ECs and the induction of SEs, suggesting that the development of this system might help to reduce the culture period for the somatic embryo production.

Rectangular Microstrip Patch Antenna with Semicircular Structure for 5G Applications (5G 응용을 위한 반원형 구조를 가진 사각형 마이크로스트립 패치 안테나)

  • Kim, Yeong-Jin;Maharjan, Janam;Choi, Dong-You
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.23 no.10
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    • pp.1269-1274
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    • 2019
  • The paper presents a design of simple four-element microstrip-patch array antenna that is suitable for 5G applications. The proposed array consists of four rectangular microstrip patch elements with semicircular etches made on both sides of each elements. The antenna is fed using the combination of series and corporate feeding networks. The size of the ground is also changed to improve the antenna frequency. Finally, yagi elements are also added to improve the directive gain of the antenna. The presented microstrip patch array is able to achieve wide frequency bandwidth of 21.95-31.86 GHz. The antenna has also attained gain of 9.7 dB at 28 GHz and has maintained high gain and high directivity throughout the frequency band. The proposed array antenna fed by series-corporate feeding network, with low profile and simple structure is a good candidate for 5G applications.

The Design of Cavity Filter to enhance the Group Delay characteristics for 5G Mobile Communication Repeater (군 지연 특성을 개선한 5G 이동통신 중계기용 캐비티 필터의 설계)

  • Yoo, Soo-Hyung;Jin, Duck-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.26 no.7
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    • pp.1032-1039
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    • 2022
  • In this paper, we designed and implemented a cavity bandpass filter combined with a cross-coupling equalizer structure to enhance Group delay for 5G mobile network repeater, which can replace the SAW (Surface Acoustic Wave) type bandwidth filter used in the existing mobile communication system. Using the 3D EM simulation tool (HFSS), the resonance frequency, the coupling coefficient between resonators, and external quality coefficient between resonators were calculated. Based on this, a 12th bandpass filter was constructed to have attenuation characteristics of more than 20dB at the edge end of both sides of the band with a metal cavity structure with a frequency band of 3500MHz to 3600MHz and bandwidth of 97.85MHz. The designed bandpass filter satisfies the group delay time requirement for the 5G mobile communication standard and the in-band and out-band frequency responses.

A Novel Mobility Management Scheme for Time Sensitive Communications in 5G-TSN

  • Kim, Jae-Hyun
    • Journal of the Korea Society of Computer and Information
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    • v.27 no.10
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    • pp.105-113
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    • 2022
  • In this paper, we present and analyze 5G system and IEEE time-sensitive networking(TSN) and propose a novel mobility management scheme for time sensitive communications in 5G-TSN to support ultra-low latency networks. Time-sensitive networking(TSN) has a promising future in the Industrial Automation and Industrial Internet of Things(IIoT), as a key technology that is able to provide low-latency, high-reliable and deterministic communications over the Ethernet. When a TSN capable UE moves the TSN service coverage from the non-TSN service coverage, the UE cannot get the TSN service promptly because the related mobility management is not performed appropriately. For the mobility situation with the TSN service coverage, the proposed scheme reports TSN capability to the network and triggers the initial registration in order to be provided the TSN service immediately and ultra-low latency communications compared to existing schemes in 5G mobile networks.

Frequency Sharing of Cellular TDD-OFDMA Systems beyond 3G with Terrestrial Fixed Systems (TDD-OFDMA 기반의 차세대 셀룰라 시스템과 육상 고정 시스템 간의 주파수 공유 분석)

  • Jo, Han-Shin;Yoon, Hyun-Goo;Yook, Jong-Gwan
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.1A
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    • pp.125-133
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    • 2007
  • In this paper, the frequency sharing issue between cellular time division duplex-orthogonal frequency division multiple access (TDD-OFDMA) Systems and terrestrial Fixed Systems has been studied. The conventional advanced minimum coupling loss (A-MCL) includes only the formulation to calculate the interference from one interfering system. Therefore, A-MCL must be modified to assess the aggregated interference from base stations(BS) and mobile stations(MS). By applying the modified model, the coexistence analysis are done according to the average number of MS per sector, BS-to-BS distance, and the main beam direction of the terrestrial fixed system. In the case of 20 MS per sector, the BS-to-BS distance and the minimum distance between a terrestrial fixed system and BS are 5.8 km and 2.5 km, respectively. It is about 25dB that the difference between maximum and minimum interference signal power which varies with the main beam direction of the terrestrial fixed system. Moreover, for 40% of the main beam direction of the terrestrial fixed system, interference signal power is less than the maximum permissible interference.