• Title/Summary/Keyword: Multiple Input Multiple Output

검색결과 1,145건 처리시간 0.021초

Analysis of Efficiencies for Multiple-Input Multiple-Output Wireless Power Transfer Systems

  • Kim, Sejin;Lee, Bomson
    • Journal of electromagnetic engineering and science
    • /
    • 제16권2호
    • /
    • pp.126-133
    • /
    • 2016
  • Wireless power transfer (WPT) efficiencies for multiple-input multiple-output (MIMO) systems are formulated with a goal of achieving their maximums using Z matrices. The maximum efficiencies for any arbitrarily given configurations are obtained using optimum loads, which can be determined numerically through adequate optimization procedures in general. For some simpler special cases (single-input single-output, single-input multiple-output, and multiple-input single-output) of the MIMO systems, the efficiencies and optimum loads to maximize them can be obtained using closed-form expressions. These closed-form solutions give us more physical insight into the given WPT problem. These efficiencies are evaluated theoretically based on the presented formulation and also verified with comparisons with circuit- and EM-simulation results. They are shown to lead to a good agreement. This work may be useful for construction of the wireless Internet of Things, especially employed with energy autonomy.

Nonorthogonal multiple access multiple input multiple output communications with harvested energy: Performance evaluation

  • Toi Le-Thanh;Khuong Ho-Van
    • ETRI Journal
    • /
    • 제46권3호
    • /
    • pp.432-445
    • /
    • 2024
  • This paper demonstrates improved throughput and energy efficiency of wireless communications by exploiting nonorthogonal multiple access (NOMA), multiple input-multiple output (MIMO), and radio frequency energy harvesting (EH) technologies. To assess the performance of NOMA MIMO communications with EH (MMe), we consider the nonlinear characteristics of EH devices and propose explicit expressions for throughput and outage probability. Based on our results, the system performance is significantly mitigated by EH nonlinearity and is considerably improved by increasing the number of antennas. Additionally, by appropriately adjusting the system parameters, our NOMA MMe innovation can avert complete outages while optimizing system performance. Moreover, the results demonstrate the superiority of the NOMA MMe over its orthogonal multiple access MMe counterparts.

Input-Series Multiple-Output Auxiliary Power Supply Scheme Based on Transformer-Integration for High-Input-Voltage Applications

  • Meng, Tao;Ben, Hongqi;Wei, Guo
    • Journal of Power Electronics
    • /
    • 제12권3호
    • /
    • pp.439-447
    • /
    • 2012
  • In this paper, an input-series auxiliary power supply scheme is proposed, which is suitable for high input voltage and multiple-output applications. The power supply scheme is based on a two-transistor forward topology, all of the series modules have a common duty ratio, all the switches are turned on and off simultaneously, and the whole circuit has a single power transformer. It does not require an additional controller but still achieves efficient input voltage sharing (IVS) for each series module through its inherent transformer-integration strategy. The IVS process of this power supply scheme is analyzed in detail and the design considerations for the related parameters are given. Finally, a 100W multiple-output auxiliary power supply prototype is built, and the experimental results verify the feasibility of the proposed scheme and the validity of the theoretical analysis.

3차원 Multiple-Input Multiple-Output 간섭계 ISAR 영상형성기법 (3-D Multiple-Input Multiple-Output Interferometric ISAR Imaging)

  • 강병수;배지훈;양은정;김경태
    • 한국전자파학회논문지
    • /
    • 제26권6호
    • /
    • pp.564-571
    • /
    • 2015
  • 본 논문에서는 다중입력-다중출력(multiple-input, multiple-output: MIMO) 간섭계(interferometric) 레이다 네트워크 시스템을 기반한 MIMO 간섭계 역합성 개구면 레이다(inverse synthetic aparture radar: InISAR) 영상 형성기법에 관해 연구하였다. MIMO 간섭계 레이다 네트워크 시스템 내에서는 여러 바이스태틱 InISAR 영상들이 형성되며, 이들을 인코히리언트(incoherent)하게 합성함으로써 MIMO InISAR 영상을 형성할 수 있다. 여기서, 바이스태틱 InISAR 영상은 바이스태틱 기하구조 내에서의 표적에 대한 산란분포를 3차원의 형태로 도시한다. 상기 MIMO InISAR 영상에서는 다중 각도에서의 바이스태틱 산란 현상을 3차원의 형태로 도시하기 때문에, 표적의 다양한 산란 정보를 제공함과 더불어, 표적 식별 시 유용한 특징 벡터(feature vector)로써 활용될 수 있다. 시뮬레이션을 통해, 제안된 MIMO InISAR 영상 형성 기법을 이용함으로써 표적에 대한 다중각도에서의 바이스태틱 산란분포가 3차원의 형태로 도시되는 것을 확인할 수 있다.

W-ZF 기법을 이용한 MIMO-FTN 송수신 구조 연구 (MIMO-FTN Transceiver Structure Using W-ZF Method)

  • 서정현;정지원
    • 한국정보통신학회논문지
    • /
    • 제21권7호
    • /
    • pp.1291-1298
    • /
    • 2017
  • 본 논문에서는 무선 통신에서의 높은 전송률과 신뢰도 있는 무선 통신 방안 중 터보 부호를 이용한 MIMO(Multiple Input Multiple Output) 통신 기법과 FTN(Faster Than Nyquist) 기법을 접목시켜 전송률을 향상시키며 신뢰성을 높일 수 있는 복호 방법을 제안한다. 기존의 계층적 시공간 부호화 기반의 MIMO-FTN(Multiple Input Multiple Output-Faster Than Nyquist) 기법은 FTN으로 인한 인접 심볼 간섭을 제거하기 위한 시공간 부호화 방식의 적용으로 전송률의 손해를 초래한다. 이러한 문제점을 해결하기 위해 본 논문에서는 ZF(Zero Forcing) 기법을 이용한 MIMO-FTN 기법에서 ZF 기법의 단점을 보완한 W-ZF(Weighted-Zero Forcing)을 이용한 방식을 제안한다. 본 논문에서는, 시뮬레이션을 통해 계층적 시공간 부호화 기반의 MIMO-FTN 기법과, W-ZF을 적용한 MIMO-FTN 기법, SISO-FTN 기법에서 FTN의 간섭량에 따른 성능과 전송률을 비교 하였다. 그 결과 W-ZF 기법을 적용한 MIMO-FTN 기법이 다른 두 기법보다 전송률에서 2배 더 좋은 것을 확인할 수 있다.

Compensation Algorithm of Arrival Time Mismatch in the Space-Time Coded Systems

  • Kim, Min-Hyuk;Choi, Suk-Soon;Jung, Ji-Won;Lee, Seong-Ro;Cho, Han-Na;Choi, Myeong-Soo
    • Journal of information and communication convergence engineering
    • /
    • 제6권3호
    • /
    • pp.353-357
    • /
    • 2008
  • One objective in developing the next generation of wireless communication systems is to increase data rates and reliability. A promising way to achieve this is to combine multiple-input and multiple-output signal processing with a space-time coding scheme, which offers higher coding and diversity gains and improves the spectrum efficiency and reliability of a wireless communication system. It is noted, however, that time delay differences and phase differences among different channels increase symbol interference and degrade system performance. In this letter, we investigate phase differences and their effects on multiple-input and multiple-output systems, and propose a compensation algorithm for the Rayleigh fading model to minimize their effects.

다중 사용자 MIMO 시스템을 위한 순차적 영공간 계산 (Recursive Nullspace Calculation for Multiuser MIMO Systems)

  • 정진곤;이용훈
    • 한국통신학회논문지
    • /
    • 제32권12A호
    • /
    • pp.1238-1243
    • /
    • 2007
  • 본 논문에서는 zero-forcing (ZF) 기반 다중 사용자 MIMO (multiple-input multiple-output) 시스템에서, 송신-처리-행렬을 구하기 위한 간단한 순차적 (recursive) nulling 행렬 계산 알고리즘을 제안한다. 제안한 방식은 채널 행렬의 부분 행렬을 써서 구한 nulling 행렬을 이용하여 전체 행렬의 nulling 행렬과 송신-처리-행렬을 구하는 방식으로써, 전체 채널 행렬을 이용하여 송신-처리-행렬을 구하는 기존 방식에 비해 계산량을 줄일 수 있다.

The Phase Estimation Algorithm of Arrival Phase Differences in Space-Time Coded Communication

  • Jung, Ji-Won;Huang, Xinping;Caron, Mario;Kim, Min-Hyuk;Kim, Ki-Man;Yun, Young
    • ETRI Journal
    • /
    • 제28권5호
    • /
    • pp.680-683
    • /
    • 2006
  • One objective in developing the next generation of wireless communication systems is to increase data rates and reliability. A promising way to achieve this is to combine multiple-input and multiple-output signal processing with a space-time coding scheme, which offers higher coding and diversity gains and improves the spectrum efficiency and reliability of a wireless communication system. It is noted, however, that time delay differences and phase differences among different channels increase symbol interference and degrade system performance. In this letter, we investigate phase differences and their effects on multiple-input and multiple-output systems, and propose a compensation algorithm for the Rayleigh fading model to minimize their effects.

  • PDF

하향링크 다중 사용자 MIMO 시스템에서의 Zero-Forcing 빔 형성을 이용한 효과적인 사용자 선택 기법 (An Efficient User Selection Algorithm in Downlink Multiuser MIMO Systems with Zero-Forcing Beamforming)

  • 고현성;오태열;최승원
    • 한국통신학회논문지
    • /
    • 제34권6A호
    • /
    • pp.494-499
    • /
    • 2009
  • 본 논문에서는 하향링크 다중 사용자 Multiple Input Multiple Output (MIMO) 채널 환경에서 시스템 용량을 최대화시키기 위한 효과적인 사용자 선택 기법에 대해서 논의한다. 본 논문에서 제안하는 방법은 사용자 채널 파워와 채널 간의 각도를 이용하여 최적의 사용자 집단을 선택하는 새로운 방법이다. 이 방법은 SUS 방법에 비해 허용 상관도 값을 별도로 생각하지 않아도 되기 때문에 간단한 방법이며, 시스템 성능을 최대화시키는 사용자들을 찾는 방법이기 때문에 향상된 성능을 보인다.

Co-located and space-shared multiple-input multiple-output antenna module and its applications in 12 × 12 multiple-input multiple-output systems

  • Longyue Qu;Haiyan Piao;Guohui Dong
    • ETRI Journal
    • /
    • 제45권2호
    • /
    • pp.203-212
    • /
    • 2023
  • In this study, we developed a co-located and space-shared multiple-input multiple-output (MIMO) antenna module with a modular design and high integration level. The proposed antenna pair includes a half-wavelength loop antenna and a dipole-type antenna printed on the front and back sides of a compact modular board. Owing to their modal orthogonality, these two independent antenna elements are highly self-isolated and free of additional decoupling components, even though they are assembled at the same location and within the same space. Thus, the proposed antenna is attractive in 5G MIMO systems. Furthermore, the proposed co-located and space-shared MIMO antenna module was employed in a 5G smartphone to verify their radiation and diversity performances. A 12 × 12 MIMO antenna system was simulated and fabricated using the proposed module. Based on the results, the proposed module can be employed in large-scale MIMO antenna systems for current and future terminal devices owing to its high integration, compactness, simple implementation, and inherent isolation.