• 제목/요약/키워드: Multiple Input Multiple Output Systems

검색결과 552건 처리시간 0.024초

Two-Way Relaying-Based Two-Hop Two-User Multiple-Input Multiple-Output System

  • Cho, Young Seek;Choi, Seyeong
    • Journal of information and communication convergence engineering
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    • 제12권2호
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    • pp.67-74
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    • 2014
  • In multi-hop communication systems, two-way relaying is one of the solutions to mitigate the spectral efficiency loss caused by a half-duplex transmission. In this paper, a simple two-way relaying scheme is proposed for two-hop two-user multiple input multiple output (MIMO) systems. In the proposed system, a base station and a relay station (RS), both equipped with two antennas, form a point-to-point MIMO channel, while the RS and two single-antenna mobile users form a point-to-multipoint multiuser (MU)-MIMO channel. Numerical examples show that the proposed system achieves a significant sum rate gain as compared to a one-way relaying system as the distance between a relay and the two users decreases. We also show that although we can expand the proposed scheme to more than two users, its performance gain as compared to that of one-way relaying decreases with an increase in the number of users.

Transceiver Optimization for the Multi-Antenna Downlink in MIMO Cognitive System

  • Zhu, Wentao;Yang, Jingbo;Jia, Tingting;Liu, Xu
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제9권12호
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    • pp.5015-5027
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    • 2015
  • Transceiver optimization in multiple input multiple output (MIMO) cognitive systems is studied in this paper. The joint transceiver beamformer design is introduced to minimize the transmit power at secondary base station (SBS) while simultaneously controlling the interference to primary users (PUs) and satisfying the secondary users (SUs) signal-to-interference-plus-noise ratio (SINR) based on the convex optimization method. Due to the limited cooperation between SBS and PUs, the channel state information (CSI) usually cannot be obtained perfectly at the SBS in cognitive system. In this study, both perfect and imperfect CSI scenarios are considered in the beamformer design, and the proposed method is robust to CSI error. Numerical results validate the effectiveness of the proposed algorithm.

A Low Complexity Multi-level Sphere Decoder for MIMO Systems with QAM signals

  • Pham, Van-Su;Yoon, Gi-Wan
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2008년도 추계종합학술대회 B
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    • pp.890-893
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    • 2008
  • In this paper, we present a low complexity modified multi-level sphere decoder (SD) for multiple-input multiple-output (MIMO) systems employing quadrature amplitude modulation (QAM) signals. The proposed decoder, exploiting the multi-level structure of the QAM signal scheme, first decomposes the high-level constellation into low-level 4-QAM constellations, so-called sub-constellations. Then, it deploys SD in the sub-constellations in parallel. In addition, in the searching stage, it uses the optimal low-complexity sort method. Computer simulation results show that the proposed decoder can provide near optimal maximum-likelihood (ML) performance while it significantly reduces the computational load.

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ML검출 기반 공간다중화 MIMO 시스템의 UEP 프리코더 선정기술 (UEP Precoder Selection Technique for ML Detected SM MIMO Systems)

  • 박재영;김재권
    • 한국통신학회논문지
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    • 제42권4호
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    • pp.747-749
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    • 2017
  • 본 논문에서는 maximum-likelihood (ML) 신호검출을 사용하는 공간다중화 multiple-input multiple-output (MIMO) 시스템을 위한 새로운 unequal error protection (UEP) 프리코더 선정기술을 제안한다. 기존 프리코더 선정기술들은 UEP를 고려하지 않고 설계되었으나, 제안된 기술은 다중안테나 UEP를 고려한다. 모의실험을 통해 제안된 기술의 적용에 따른 향상된 다중안테나 UEP 성능을 확인한다.

Spatial Multiuser Access for Reverse Link of Multiuser MIMO Systems

  • 신오순
    • 한국통신학회논문지
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    • 제33권10A호
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    • pp.980-986
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    • 2008
  • Spatial multiuser access is investigated for the reverse link of multiuser multiple-input multiple-output (MIMO) systems. In particular, we consider two alternative a aches to spatial multiuser access that adopt the same detection algorithm at the base station: one is a closed-loop approach based on singular value decomposition (SVD) of the channel matrix, whereas the other is an open-loop approach based in space-time block coding (STBC). We develop multiuser detection algorithms for these two spatial multiuser access schemes based on the minimum mean square error (MMSE) criterion. Then, we compare the bit error rate (BER) performance of the two schemes and a single-user MIMO scheme. Interestingly, it is found that the STBC approach can provide much better BER performance than the SVD approach as well as than a single-user MIMO scheme.

Performance Analysis of Layer Pruning on Sphere Decoding in MIMO Systems

  • Karthikeyan, Madurakavi;Saraswady, D.
    • ETRI Journal
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    • 제36권4호
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    • pp.564-571
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    • 2014
  • Sphere decoding (SD) for multiple-input and multiple-output systems is a well-recognized approach for achieving near-maximum likelihood performance with reduced complexity. SD is a tree search process, whereby a large number of nodes can be searched in an effort to find an estimation of a transmitted symbol vector. In this paper, a simple and generalized approach called layer pruning is proposed to achieve complexity reduction in SD. Pruning a layer from a search process reduces the total number of nodes in a sphere search. The symbols corresponding to the pruned layer are obtained by adopting a QRM-MLD receiver. Simulation results show that the proposed method reduces the number of nodes to be searched for decoding the transmitted symbols by maintaining negligible performance loss. The proposed technique reduces the complexity by 35% to 42% in the low and medium signal-to-noise ratio regime. To demonstrate the potential of our method, we compare the results with another well-known method - namely, probabilistic tree pruning SD.

Spatial Multiplexing Receivers in UWB MIMO Systems based on Prerake Combining

  • An, Jin-Young;Kim, Sang-Choon
    • Journal of information and communication convergence engineering
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    • 제9권4호
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    • pp.385-390
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    • 2011
  • In this paper, various ultra-wideband (UWB) spatial multiplxing (SM) multiple input multiple output (MIMO) receivers based on a prerake diversity combining scheme are discussed and their performance is analyzed. Several UWB MIMO detection approaches such as zero forcing (ZF), minimum mean square error (MMSE), ordered successive interference cancellation (OSIC), sorted QR decomposition (SQRD), and maximum likelihood (ML) are considered in order to cope with inter-channel interference. The UWB SM systems based on transmitter-side multipath preprocessing and receiver-side MIMO detection can either boost the transmission data rate or offer significant diversity gain and improved BER performance. The error performance and complexity of linear and nonlinear detection algorithms are comparatively studied on a lognormal multipath fading channel.

A Comparative Study of List Sphere Decoders for MIMO Systems

  • Pham, Van-Su;Yoon, Giwan
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2009년도 춘계학술대회
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    • pp.143-146
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    • 2009
  • In this paper, we investigated the list sphere decoders (LSD) for multiple-input multiple-output (MIMO) systems. We showed that the ordering procedures play an important role in LSD in order to achieve the low complexity without degrading the bit-error-rate (BER) performance. Then, we proposed a novel ordering algorithm for the LSD which uses a look-up table and simply comparative operations. Comparative results in terms of BER performance and computational complexity are provided through computer simulations.

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MIMO 시스템에서 ALAMOUTI 기법과 IEEE 802.15.4의 BER 성능 개선 (Improving BER Performance of IEEE 802.15.4 with Alamouti Scheme in MIMO System)

  • 에디 하토노 할림;신수용
    • 인터넷정보학회논문지
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    • 제14권1호
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    • pp.1-7
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    • 2013
  • 본 논문은 IEEE 802.15.4 표준 기반의 Multiple Inputs Multiple Output (MIMO) 시스템에 space-time block coding (STBC) - Alamouti scheme을 적용하는 기법을 제안한다. 제안된 기법은 IEEE 802.15.4 표준을 기반으로 하는 $2{\times}1$ MISO와 $2{\times}2$ MIMO에 적용되었다. Matlab을 이용한 모의 실험을 수행하였고, 그 결과를 기존의 IEEE 802.15.4 Single Input Single Output (SISO) system과 switching diversity $1{\times}2$ Single Input Multiple Output (SIMO)와 비교하였다. 모의 실험 결과 제안된 기법은 IEEE 802.15.4 SISO 및 switching diversity 방식에 비해 더 나은 Bit Error Rate (Ber) 성능을 보이는 것을 입증하였다.

A Novel Adaptive Turbo Receiver for Large-Scale MIMO Communications

  • Chang, Yu-Kuan;Ueng, Fang-Biau;Tsai, Bo-Yi
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제12권7호
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    • pp.2998-3017
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    • 2018
  • Massive (large-scale) MIMO (multiple-input multiple-output) is one of the key technologies in next-generation wireless communication systems. This paper proposes a high-performance low-complexity turbo receiver for SC-FDMA (single-carrier frequency-division multiple access) based MMIMO (massive MIMO) systems. Because SC-FDMA technology has the desirable characteristics of OFDMA (orthogonal frequency division multiple access) and the low PAPR (peak-to-average power ratio) of SC transmission schemes, the 3GPP LTE (long-term evolution) has adopted it as the uplink transmission to meet the demand high data rate and low error rate performance. The complexity of computing will be increased greatly in base station with massive MIMO (MMIMO) system. In this paper, a low-complexity adaptive turbo equalization receiver based on normalized minimal symbol-error-rate for MMIMO SC-FDMA system is proposed. The proposed receiver is with low complexity than that of the conventional turbo MMSE (minimum mean square error) equalizer and is also with better bit error rate (BER) performance than that of the conventional adaptive turbo MMSE equalizer. Simulation results confirm the effectiveness of the proposed scheme.