• Title/Summary/Keyword: 대규모 MIMO

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32×32 Full-Rate Massive MIMO Using Quasi-Orthogonal Space-Time Block Code (QOSTBC) (준직교 공간시간 블록부호를 적용한 32×32 전율 대규모 MIMO 시스템)

  • Winn, Khin Zar Chi;Chung, Yeon-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.3
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    • pp.507-513
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    • 2015
  • In this paper, we present the bit-error rate (BER) performance of quasi-orthogonal space-time block code (QOSTBC) massive multiple-input multiple-output (MIMO) system employing up to 32 transmit and receive antennas. The QOSTBC, due to its advantages in transmission rate and decoding complexity, is an important transmit diversity scheme for more than 2 transmit antennas. As massive MIMO implies very large number of antennas, practically at least more than 15 antennas, a different number of transmit and receive antennas (i.e. $2{\times}2$, $4{\times}4$, $8{\times}8$, $16{\times}16$ and $32{\times}32$) using QOSTBC for the massive MIMO system are considered. The BER performance of the massive MIMO with antennas up to $32{\times}32$ using BPSK modulation scheme is analyzed. Simulation results show that the full-rate massive MIMO systems with QOSTBC give a significant performance improvement due to increasing diversity effect, compared with previously considered massive MIMO systems.

An MMSE Based Iterative Soft Decision Interference Cancellation Scheme for Massive MIMO Systems (대규모 다중 입출력 시스템을 위한 MMSE 기반 반복 연판정 간섭 제거 기법)

  • Park, Sangjoon;Choi, Sooyong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39A no.9
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    • pp.566-568
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    • 2014
  • In this letter, an MMSE based iterative soft decision interference cancellation scheme for massive MIMO systems is proposed. To reduce the complexity, the proposed scheme uses the Sherman-Morrison-Woodbury formula to compute the entire MMSE filtering vectors in one iteration by one matrix inverse operation. Simulation results show that the proposed scheme also has a comparable BER to the conventional scheme for massive MIMO systems.

A Simple Toeplitz Channel Matrix Decomposition with Vectorization Technique for Large scaled MIMO System (벡터화 기술을 이용한 대규모 MIMO 시스템의 간단한 Toeplitz 채널 행렬 분해)

  • Park, Ju Yong;Hanif, Mohammad Abu;Kim, Jeong Su;Song, Sang Seob;Lee, Moon Ho
    • Journal of the Institute of Electronics and Information Engineers
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    • v.51 no.9
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    • pp.21-29
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    • 2014
  • Due to enormous number of user and limited memory space, the memory saving is become an important issue for big data service these days. In the large scaled multiple-input multiple-output (MIMO) system, the Teoplitz channel can play the significance rule to improve the performance as well as power efficiency. In this paper, we propose a Toeplitz channel decomposition based on matrix vectorization. Here we use Toeplitz matrix to the channel for large scaled MIMO system. And we show that the Toeplitz Jacket matrices are decomposed to Cooley-Tukey sparse matrices like fast Fourier transform (FFT).

Sum-Rate Improvement Method Using Quasi-Orthogonal Beam Pairs for UCA MIMO Transmission (UCA MIMO 전송 시 준직교적 빔 쌍을 활용한 합 전송률 향상 방안)

  • Yang, Jiyeong;Kim, Huiwon;Sung, Wonjin
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.29 no.1
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    • pp.32-35
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    • 2018
  • Massive multiple-input multiple-output (MIMO) transmission is an essential technique for achieving the high bandwidth efficiency required in 5G mobile communication systems. Various forms of arrays can be used as the number of antenna elements increases for massive MIMO transmission. In this letter, we propose a beamforming algorithm applicable to multiuser MIMO transmission using uniform circular arrays. By employing quasi-orthogonal beam pairs obtained from the inter-beam correlation information, we minimize inter-user interference and evaluate the resulting performance gain.

Efficient Transmit Antenna Selection Method for Massive MIMO system (Massive MIMO 시스템을 위한 효율적인 송신 안테나 선택 기법)

  • Ju, Sang-Lim;Lee, Byung-Jin;Kim, Young-Jae;Kim, Jin-Up;Bang, Young-Jo;Kim, Kyungseok
    • Journal of Satellite, Information and Communications
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    • v.11 no.3
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    • pp.58-64
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    • 2016
  • This paper proposes the efficient transmit antenna selection (TAS) scheme considering trade-off between the performance and the complexity in massive MIMO system. The massive MIMO system is a core technology to achieve performance objectives for 5 generation wireless communication. It achieve high spectral efficiency, a reliability, and a diversity gain. However many RF chains required by massive transmit antennas equipped in a base station create the problem such as high hardware cost and complexity. Therefor we investigates the transmit antenna selection scheme, in which the number of RF chains of BS is reduced, and the trade-off between the performance and the complexity is considered for proposed scheme. And, the spectral efficiency and complexity are analysed by transmit antenna selection schemes.

Blind Channel Estimation based on Hadamard Matrix Interstream Transmission for Multi-Cell MIMO Networks (다중 셀 MIMO 네트워크를 위한 Hadamard 행렬 Interstream 전송 기반 Blind 채널 추정)

  • Yang, Jae-Seung;Hanif, Mohammad Abu;Park, Ju-Yong;Lee, Moon-Ho
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.15 no.4
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    • pp.119-125
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    • 2015
  • In this paper, we introduce a Hadamard matrix interstream transmission based blind channel estimation for multi-cells multiple-input and multiple-output (MIMO) networks. The proposed scheme is based on a network with mobile stations (MS) which are deployed with multi cells. We assume that the MS have the signals from both cells. The signal from near cell are considered as desired signal and the signals from the other cells are interference signal. Since the channel is blind, so that we transmit Hadamard matrix pattern pilot stream to estimate the channel; that gives easier and fast channel estimation for large scale MIMO channel. The computation of Hadamard based system takes only complex additions, and thus the complexity of which is much lower than the scheme with Fourier transform since complex multiplications are not needed. The numerical analysis will give perfection of proposed channel estimation.

Current Status and Prospect of WiBro Market (WiBro 시장 현황 및 전망)

  • Seok, W.H.;LEE, K.S.;Song, Y.K.
    • Electronics and Telecommunications Trends
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    • v.26 no.4
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    • pp.165-174
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    • 2011
  • 삼성전자와 한국전자통신연구원이 공동으로 기술개발에 성공하여 2006년 6월 국내에서 세계 최초로 서비스를 개시한 WiBro는 최대 전송속도 하향 75Mbps($2{\times}2$ MIMO)/상향 50Mbps($1{\times}n$ MIMO), 시속 250km/h로 이동하면서 사용할 수 있는 기술이다. 2011년 1분기 기준 전세계 90개국 195개 사업자가 WiBro 서비스를 제공 또는 준비 중인데, 최근 대규모 WiBro 사업자인 러시아 Yota와 미국 Clearwire가 LTE로의 전환 가능성을 시사하는 등 글로벌 WiBro 사업에 대한 위기감이 나타나고 있다. 본 고에서는 국내외의 WiBro의 시장 현황 및 전망을 살펴보고, 국내로의 시사점을 모색해보고자 한다.

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Design and Performance Gain Evaluation of a Multi-Rank Codebook Utilizing Statistical Properties of the Spatial Channel Model (공간 채널 모델의 통계적 특성을 반영한 다중 랭크 코드북의 설계 및 성능 이득 평가)

  • Kim, Changhyeon;Sung, Wonjin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.7
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    • pp.723-731
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    • 2016
  • A core technological base to provide enhanced data rates required by 5G mobile wireless communications is the improved bandwidth efficiency using massive multiple-input multiple-output (MIMO) transmission. MIMO transmission requires the channel estimation using the channel state information reference signaling (CSI-RS) and appropriate beamforming, thus the design of the codebook defining proper beamforming vectors is an important issue. In this paper, we propose a multi-rank codebook based on the discrete Fourier transform (DFT) matrix, by utilizing statistical properties of the channel generated by the spatial channel model (SCM). The proposed method includes a structural change of the precoding matrix indicator (PMI) by considering the phase difference distributions between adjacent antenna elements, as well as the selected codevector characteristics of each transmission layer. Performance gain of the proposed method is evaluated and verified by making the performance comparison to the 3GPP standard codebooks adopted by Long-Term Evolution (LTE) systems.

Deep Reinforcement Learning based Antenna Selection Scheme For Reducing Complexity and Feedback Overhead of Massive Antenna Systems (거대 다중 안테나 시스템의 복잡도와 피드백 오버헤드 감소를 위한 심화 강화학습 기반 안테나 선택 기법)

  • Kim, Ryun-Woo;Jeong, Moo-Woong;Ban, Tae-Won
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.25 no.11
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    • pp.1559-1565
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    • 2021
  • In this paper, an antenna selection scheme is proposed in massive multi-user multiple input multiple output (MU-MIMO) systems. The proposed antenna selection scheme can achieve almost the same performance as a conventional scheme while significantly reducing the overhead of feedback by using deep reinforcement learning (DRL). Each user compares the channel gains of massive antennas in base station (BS) to the L-largest channel gain, converts them to one-bit binary numbers, and feed them back to BS. Thus, the feedback overhead can be significantly reduced. In the proposed scheme, DRL is adopted to prevent the performance loss that might be caused by the reduced feedback information. We carried out extensive Monte-Carlo simulations to analyze the performance of the proposed scheme and it was shown that the proposed scheme can achieve almost the same average sum-rates as a conventional scheme that is almost optimal.

Design and Implementation of High-Performance Parallel Fuzzy Architecture (고성능 병렬 퍼지 아키텍처의 설계 및 구현)

  • Lee, Sang-Gu
    • The Transactions of the Korea Information Processing Society
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    • v.5 no.7
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    • pp.1791-1800
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    • 1998
  • 본 논문에서는 Mamdani 방법과 Koczy 방법의 퍼지 추론 알고리즘에 대햇 병렬머신에 적합한 병렬 퍼지 추론 방법을 제안하고, 효율적인 병렬 퍼지 아키텍처를 설계한다. 제안된 아키텍처는 비교적 높은 성능을 갖고, 확장이 용이한 구조로서, 여러개의 FPE(Fuzzy Processing Element), CP(Control Processor), 메모리 모듈, 상호연결망 및 Min 회로로 구성되어 있다. 이러한 구조의 특징은 iqjsWo의 FPE는 I번째의 전건부 및 I번째의 후건부의 처리만을 수행하기 때문에 전건부, 변수들의 처리는 각각 병렬도 수행되고, 후건부의 처리도 또한 각각 병렬로 수행된다. 따라서 프로세서의 활용도가 높아지며, 전건부와 후건부의 변수, 퍼지규칙의수에 관계없이 쉽게 구성할 수 있다. 이러한 구조는 실시간에 고속추론을 요하는 시스템 또는 전건부와 후건부의 변수가 많은 대규모 전문가 시스템에 사용되어 질 수 있으며, MISO(Multiple-input, Single-output) 시스템보다 MIMO(Multiple-input, Multiple-output) 시스템에 특히 적합하다.

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