• ETRI Journal
• /
• 제39권5호
• /
• pp.707-717
• /
• 2017

This paper presents a novel generalized quadrature spatial modulation (GQSM) transmission scheme using antenna grouping. The proposed GQSM scheme combines QSM and conventional spatial multiplexing (SMux) techniques in order to improve the spectral efficiency (SE) of the system. Analytical and simulation results show that the proposed transmission scheme has minimal losses in terms of the average bit error probability along with the advantage of an increased SE compared with previous SM and QSM schemes. For the case studies, this advantage represents a reduction of up to 81% in terms of the number of required transmit antennas compared with QSM. In addition, a detection architecture based on the ordered successive interference cancellation scheme and the QR decomposition is presented. The proposed QRD-M adaptive algorithm showed a near-maximum-likelihood performance with a complexity reduction of approximately 90%.

• 한국산학기술학회논문지
• /
• 제20권4호
• /
• pp.15-24
• /
• 2019

다목적훈련지원정(MTB)에 탑재되는 전자전훈련지원체계(EWT) 송신 신호에 의해 MOSCOS 간 전자기간섭 문제점을 해결하기 위한 안테나 최적 위치에 대한 연구를 수행하였다. 이를 위해 4M1E에 근거한 Fishbone Diagram을 이용하여 7가지의 원인을 식별하였으며 Friis 전달공식을 통해 고려해야 할 요소를 식별하고 기존 함정에서 발생한 유사 문제점을 분석한 후, 두 개의 최적 배치 후보를 선정하였다. 두 개의 설치 위치에 대해 전자기 수신 레벨을 측정하여 최적배치(안)을 수립한 후, 본 개선사항에 대한 실선 시험을 통해 전자기 간섭 개선 효과를 확인하였다.

• 디지털산업정보학회논문지
• /
• 제15권1호
• /
• pp.67-76
• /
• 2019

Despite attractive advantages such as good time-frequency localization and improved spectral efficiency, filter bank multicarrier with offset quadrature amplitude modulation (FBMC/OQAM) suffers from multipath fading. In highly frequency-selective channels, the effect of multipath interference can significantly distort the FBMC/OQAM signal due to the absence of cyclic prefix. To resolve the problem of the multipath interference in FBMC/OQAM, this paper proposes applying an antenna array that provides well shaped beam pattern for each multipath. To evaluate the performance of the proposed array system, various computer simulations have been conducted. The accuracy of direction of arrival estimation is demonstrated through spatial spectrum for a different number of antennas in a sub-array. The performance improvement is presented in terms of bit error rate. We found that the proposed array system mitigate the multipath interferences in Extended Typical Urban model with 12 antennas in a sub-array. Moreover, as the number of antennas in a sub-array increases, the system provides a signal-to-noise ratio gain.

• International Journal of Internet, Broadcasting and Communication
• /
• 제11권3호
• /
• pp.34-40
• /
• 2019

In spatial modulation (SM), both the signal symbol and spatial symbol, i.e., the index of the antenna from which signal symbol is transmitted, carry information. To increase the number of bits carried by spatial symbols, more transmit antennas are required. In the generalized SM (GSM), the same signal symbol is transmitted from a combination of antennas, resulting in a reduction in the number of antennas required to achieve a given spectral efficiency. In this paper, we propose a rotated-symbol GSM (RGSM), in which the signal symbol is rotated with an angle corresponding to the position of the antenna index within the combination. This increases the number of spatial symbols by a factor equivalent to the length of the antenna combinations of the GSM. Numerically, SM, GSM and RGSM require 128, 17 and 12 transmit antennas to convey seven bits through the spatial symbols. Simulation results show that RGSM performs relatively close to GSM, and in several system settings, their error performances coincide.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
• /
• pp.408-411
• /
• 2004

The presence of voids behind tunnel linings results in their deterioration. One proposed method of effectively detecting such voids by non-destructive means is radar. This research is devoted to quantitatively evaluating the efficiency of such non-destructive tests with radar. As a foundation to this ongoing research, which aims to acquire directional information and estimate the shape of specific voids using radar of three-dipole antenna type, an investigation of microwave polarization methods is carried out with various void orientations and void geometries. As the results, it is clarified that the response of microwave polarization modes depends on void geometry and thus there is a possibility of identifying the geometry and orientation of specific voids using radar of three-dipole antenna type.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2004년도 학술대회 논문집
• /
• pp.3-7
• /
• 2004

An electric power efficiency of electrodeless fluorescent lamp has big relativie property of gas in lamp, gas pressure, lamp formation, ingredients of magnetic substance and shape and action frequency etc. We used magnetic substance that open self-examination material of electrodeless fluorescent lamp antenna. Ferrite that is used in this experiment was Mn-Zn type. We have examined resistance kind, impedance, Q-factor's frequency characteristic by ferrite. Impedance, resistance and capacitance did not show difference in start frequency 2.65 [MHz] but there was difference quantity. We could know Q-factor's difference according to material, and Q-factor's is important part of antenna design.

• 한국전기전자재료학회논문지
• /
• 제19권2호
• /
• pp.200-206
• /
• 2006

An electric power efficiency of electrodeless fluorescent lamp depens on a big relative property of gas, gas pressure, lamp formation, ingredients of magnetic substance and shape and action frequency etc. in lamp. We used magnetic substance that opens self-examination material of electrodeless fluorescent lamp antenna. We used Mn-Zn type as the Ferrite. We have examined resistance, impedance and Q-factor's frequency characteristic by ferrite. Coil turns were changed from 13 to 15 turns to recognize brightness change of lamp by winding number. Optical equipment (LS-100) was used to measure brightness. We could know Q-factor's difference according to material is important part of antenna design. When an electrodeless fluorescent lamp was made using T company's PE22, it showed the highest brightness. As number of winding is increased the brightness increased, and starting characteristic became good.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권4호
• /
• pp.1889-1910
• /
• 2017

This paper investigates a protocol so-called Adaptive Harvest Then Transmit (AHTT) for wireless powered communication networks (WPCNs) in multiple-input single-output (MISO) downlink systems, which assists in transmitting signals from a multi-antenna transmitter to a single-antenna receiver. Particularly, the power constrained relay is supplied with power by utilizing radio frequency (RF) signals from the source. In order to take advantage of multiple antennas, two different linear processing schemes, including Maximum Ratio Combining (MRC) and Selection Combination (SC) are studied. The system outage capacity and ergodic capacity are evaluated for performance analysis. Furthermore, the optimal power allocation is also considered. Our numerical and simulation results prove that the implementation of multiple antennas helps boost the energy harvesting capability. Therefore, this paper puts forward a new way to the energy efficiency (EE) enhancement, which contributes to better system performance.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
• /
• pp.644-647
• /
• 2004

Recently, the environmental problem has received considerable attention. so, many lamps have been developing for environmental requirement and energy efficiency, also, at glow discharge lamp researchers try to reduce energy spending that is power saving lamp. this kind requirement agree with strong points of electrodeless fluorescent lamp has received to now lighting sauce. In this paper, at the research and development of Electrodeless Fluorescent Lamp phase, according to ferrite C.F.D(Computational Fluid Dynamics) Simulation and lamp brightness character are measured to find optimization design requirements of RF antenna which is impotent for emission of lamp.

• 한국자동차공학회논문집
• /
• 제11권2호
• /
• pp.190-195
• /
• 2003

We developed a loading sleeve for Automobile, which has the PCS and IMT-2000 frequency bands. The electric characteristics of the designed sleeve monopole has SWR<1.311 and 3.0dBi in average gain for that frequency bands. In this study, the designed sleeve monopole was installed at a roof and trunk lid of vehicle. The characteristics of designed sleeve monopole was investigated by measuring SWR, input impedance and radiation pattern. The experimental results show that the efficiency of the sleeve monopole is superior th that of domestic and foreign commercial PCS antenna.