• Title/Summary/Keyword: 다중입출력 안테나

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Effect of Multiple Antennas at a Relay Node on the Performance of Physical-Layer Network Coding in Two-Way Relay Channel (양방향 중계채널에서 중계기 다중안테나가 물리계층네트워크 코딩의 성능에 미치는 영향)

  • Park, Jeonghong;Jung, Bang Chul;Ban, Tae-Won
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.20 no.8
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    • pp.1438-1443
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    • 2016
  • In this paper, we investigate the effect of multiple antennas at a relay node on the performance of physical-layer network coding (PNC) in the two-way relay channel (TWRC). We assume that two source nodes have a single antenna and the relay node has multiple antennas. We extend the conventional TWRC environment with a signle antenna at both relay and source nodes to the case of multiple antennas at the relay node. In particular, we consider two decoding strategies: separate decoding (SD) and direct decoding (DD). The SD decodes each packet from the two sources and performs the network coding with bit-wise exclusive OR (XOR) operation, while the DD decodes the network-coded packet from the two sources. Note that both decoding strategies are based on log-likelihood ratio (LLR) computation. It is shown that the bit error rate (BER) performance becomes significantly improved as the number of antennas at the relay node.

Spatial Coding using Data Information and Antenna Selection Technique in MIMO System (MIMO 시스템에서 데이터 정보와 안테나 선택 기법을 이용한 공간 부호화)

  • Song, Jae-Woong;Kim, Back-Hyun;Jeong, Rag-Gyo;Kwak, Kyung-Sup
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.11 no.6
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    • pp.81-88
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    • 2012
  • Space diversity and space multiplexing gain can be achieved with MIMO system. This paper proposes spatial coding method to MIMO system using data information and antenna selection technique. This technique provides coding gain as well as space diversity gain. For MIMO system with BPSK modulation, BER performance is analyzed and space diversity gains are compared through simulation in terms of data maldistribution degree.

A Beamformer Construction Method Via Partial Feedback of Channel State Information of MIMO Systems (다중 입출력 시스템의 부분적 채널 정보 궤환을 통한 빔포머 형성 방안)

  • Kim, Yoonsoo;Sung, Wonjin
    • Journal of the Institute of Electronics and Information Engineers
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    • v.51 no.6
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    • pp.26-33
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    • 2014
  • For wireless communication systems of (and beyond) LTE-Advanced, multiple-input multiple-output (MIMO) with an increased number of antennas will be utilized for system throughput improvement. When using such an increased number of antenna, an excessive amount of overhead in channel state information (CSI) feedback can be a serious problem. In this paper, we propose methods which reduce the CSI feedback overhead, particularly including application strategies for multi-rank transmission targeted for two or more reception antennas. To reduce the information which is instantaneously transmitted from the reception node to the transmission node, we present a beamforming method utilizing singular value decomposition (SVD) based on channel estimation of partitioned antenna arrays. Since the SVDs for partial matrices of the channel may lose the characteristics of the original unpartitioned matrix, we explain an appropriate scheme to cope with this problem.

Mode Selection Technique Between Antenna Grouping and Beamforming for MIMO Communication Systems (다중 입출력 시스템에서 안테나 그룹화와 빔 형성 사이의 모드 선택 기법)

  • Kim, Kyung-Chul;Lee, Jung-Woo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.2A
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    • pp.147-154
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    • 2009
  • Antenna grouping algorithm is hybrid of beamforming and spatial multiplexing. In antenna grouping system, we partition $N_t$ transmit antennas into $N_r$ groups and use beamforming in a group, spatial multiplexing between groups. We can transmit $N_r$ data streams in the $N_t{\times}N_r$ antenna grouping system. With antenna grouping, we can achieve diversity gain through beamforming, and high spectral efficiency through spatial multiplexing. But if channel is ill-conditioned or there are some correlations between antennas, the performance of antenna grouping is seriously degraded and in that case, beamforming is the best transmit strategy. By selecting the antenna grouping mode when channel is well-conditioned and by selecting the beamforming mode when channel is ill-conditioned, we can prevent serious fluctuation of BER performance caused by varying channel condition and achieve the best BER performance. In this paper, we investigate mode selection algorithm which can select antenna grouping mode or beamforming mode. we also propose a simple mode selection criterion.

Soft Decision-Directed Channel Estimation in MIMO-OFDM Systems (MIMO-OFDM 시스템에서의 소프트 데이터 연판정을 이용한 채널 추정 기법)

  • Park, Sunho;Shim, Byonghyo
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2015.11a
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    • pp.11-12
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    • 2015
  • 본 논문에서는 다중 입출력 안테나 OFDM 통신시스템에서 신뢰할 만한 데이터 신호 사용하는 한 연판정 지향 채널 추정 기법을 제안한다. 기존 방식에서는 주어진 기준 신호만을 이용하여 채널을 추정하는 반면에 제안하는 기법은 기준 신호를 포함하여 신뢰할 만한 데이터 신호를 동시에 사용하여 채널을 추정한다. 모의실험을 통해 제안하는 기법이 기존 채널 추정에 비해 성능이 우수함을 확인할 수 있다.

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Degrees of Freedom for MIMO Z-Interference Channels with Reconfigurable Antennas in the Absence of CSIT (송신단 채널 정보가 없는 재구성 안테나를 사용한 다중입출력 Z-간섭 채널에서의 자유도)

  • Yang, Heecheol;Lee, Jungwoo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.42 no.2
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    • pp.291-298
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    • 2017
  • In this paper, we derive the achievable degrees of freedom (DoF) for multiple-input multiple-output (MIMO) Z-interference channels (Z-IC) with reconfigurable antennas at the receivers, assuming that channel state information is not available at the transmitters. We propose a new linear scheme to align interfering signals and to decode desired signals through the designed preset mode switching pattern of reconfigurable antennas at the receivers. The key idea of our scheme is to use interfering signals as a side information at the interfered receiver by being silent at the corresponding transmitter during some time slots. Consequently, it is shown that the reconfigurable antennas at the receivers can bring a DoF gain if the number of preset modes is greater than the number of RF chains at the receivers.

New Beamforming Schemes with Optimum Receive Combining for Multiuser MIMO Downlink Channels (다중사용자 다중입출력 하향링크 시스템을 위한 최적 수신 결합을 이용한 새로운 빔 형성 기법)

  • Lee, Sang-Rim;Park, Seok-Hwan;Moon, Sung-Hyun;Lee, In-Kyu
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.48 no.8
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    • pp.15-26
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    • 2011
  • In this paper, we present a new beamforming scheme for a downlink of multiuser multiple-input multipleoutput (MIMO) communication systems. Recently, a block-diagonalization (BD) algorithm has been proposed for the multiuser MIMO downlink where both a base station and each user have multiple antennas. However, the BD algorithm is not efficient when the number of supported streams per user is smaller than that of receive antennas. Since the BD method utilizes the space based on the channel matrix without considering the receive combining, the degree of freedom for beamforming cannot be fully exploited at the transmitter. In this paper, we optimize the receive beamforming vector under a zero forcing (ZF) constraint, where all inter-user interference is driven to zero. We propose an efficient algorithm to find the optimum receive vector by an iterative procedure. The proposed algorithm requires two phase values feedforward information for the receive combining vector. Also, we present another algorithm which needs only one phase value by using a decomposition of the complex general unitary matrix. Simulation results show that the proposed beamforming scheme outperforms the conventional BD algorithm in terms of error probability and obtains the diversity enhancement by utilizing the degree of freedom at the base station.

Analysis of Communication Performance According to Detection Sequence of MMSE Soft Decision Interference Cancellation Scheme for MIMO System (다중 입출력 시스템 MMSE 연판정 간섭 제거 기법의 검출 순서에 따른 통신 성능 분석)

  • Lee, Hee-Kwon;Kim, Deok-Chan;Kim, Tae-Hyeong;Kim, Yong-Kab
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.12 no.6
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    • pp.636-642
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    • 2019
  • In this paper, we analyzed BER (Bit Error Rate) communication performance according to the detection order of MMSE (Minimum Mean Square Error) based soft decision interference cancellation. As the detection order method, antenna index order method, absolute value magnitude order method of channel elements, absolute value sum order method of channel elements, and SNR (Signal Noise Ratio) order method are proposed. BER performance for the scheme was measured and analyzed. As a simulation environment, 16-QAM (Quadrature Amplitude Modulation) modulation is used in an uncoded environment of an M×M multiple-input multiple-output system, and an independent Rayleigh attenuation channel is considered. The simulation results show that the performance gain is about 1.5dB when the SNR-based detection order method is M=4, and the performance gain is about 3.5dB when M=8 and about 3.5dB when M=16. The more BER performance was confirmed, the more the detection order method of the received signal prevented the interference and error spreading occurring in the detection process.

Adaptive MIMO Switching Algorithm Robust for Channel Estimation Error (채널추정 오차에 강인한 적응형 MIMO 신호처리 기법)

  • Choi, Joon-Sung;Eun, Chang-Soo
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.47 no.6
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    • pp.51-57
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    • 2010
  • In this paper, we propose a new adaptive MIMO switching algorithm that provides the optimal trade-off between throughput and reliability of data in MIMO system. The proposed algorithm is based on the variable packet error predictor which is robust for channel estimation error, and we show that our algorithm has a better spectrum efficiency than the conventional MIMO switching techniques about 8 percent point.

Evolution of MIMO Technology (MIMO 기술의 진화)

  • Shim, Byonghyo;Lee, Byungju
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38A no.8
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    • pp.712-723
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    • 2013
  • Recent exploration of smart-phone user is fueling the deployment of long term evolution (LTE) service that offers higher data rates service over 3G HSPA networks. In particular, Korea, mobile powerhouse, recently launched the service of LTE-Advanced (LTE-A) which is the latest release in LTE standard. Multiple-input-multiple-output (MIMO) technology is the one of key enablers for LTE and LTE-A for achieving high data rate. MIMO technology has received much attention since it is possible to achieve channel capacity in proportion to the number of antennas without increasing frequency and power. In this paper, we overview of the theoretical background of MIMO technology regarding from single-user MIMO, multiuser MIMO, and massive MIMO and design considerations to implement the communication system.