• Title/Summary/Keyword: MIMO multiplexing

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Design and Implementation of Efficient Symbol Detector for MIMO Spatial Multiplexing Systems (MIMO 공간 다중화 시스템을 위한 효율적인 심볼 검출기의 설계 및 구현)

  • Jung, Yun-Ho
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.45 no.10
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    • pp.75-82
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    • 2008
  • In this paper, we propose an efficient symbol detection algorithm for multiple-input multiple-output spatial multiplexing (MIMO-SM) systems and present its design and implementation results. By enhancing the performance of the first detected symbol which causes error propagation, the proposed algorithm achieves a considerable performance gain as compared to the conventional sorted QR decomposition (SQRD) based detection and the ordered successive detection (OSD) algorithms. The bit error rate (BER) performance of the proposed detection algorithm is evaluated by the simulation. In case of 16QAM MIMO-SM system with 4 transmit and 4 receive ($4{\times}4$) antennas, at $BER=10^{-3}$ the proposed algorithm obtains the gai improvement of about 2.5-13.5 dB over the conventional algorithms. The proposed detection algorithm was designed in a hardware description language (HDL) and synthesized to gate-level circuits using 0.18um 1.8V CMOS standard cell library. The results show that the proposed algorithm can be implemented without increasing the hardware costs significantly.

Channel Estimation scheme for IEEE 802.11a system based on MIMO-OFDM systems (IEEE 802.11a 기반의 MIMO-OFDM 시스템을 위한 채널 추정 기법)

  • 안치준;안재민
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.6A
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    • pp.640-650
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    • 2004
  • Channel estimation schemes are proposed for Multiple Input-Multiple output Orthogonal Frequency Division Multiplexing(MIMO-OFDM) systems based on the physical layer specification of the IEEE 802.1 la. By combining the space-time block coding(STBC)/ space-frequency block coding(SFBC) techniques with the transform domain interpolation, the proposed algorithms achieve more accurate channel coefficients for the MIMO channels such that improve the BER performance. The performance improvements of the proposed algorithms are evaluated by simulations under the various multipath fading channel environments and various transmission rates.

An Efficient Channel Estimation Method in MIMO-OFDM Systems (MIMO-OFDM 시스템에서 효율적인 채널 추정 방식)

  • Jeon, Hyoung-Goo;Kim, Jun-Sig
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.10
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    • pp.2275-2284
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    • 2015
  • In this paper, the Walsh coded orthogonal training signals for 4 × 4 multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) systems are designed and the channel estimation equations are derived as a closed form, taking account of the inter training signal interference problems caused by the multi-path delayed signals. The performances of the proposed channel estimation method are analyzed and compared with the conventional methods[9,14] by using computer simulation. The simulation results show that the proposed methods has better performances, compared with the conventional methods[9,14]. As a result, the proposed method can be used for MIMO-OFDM systems with null sub-carriers.

Performance of MIMO-OFDMA Systems with Multibeamforming Algorithm (다중빔 형성기법을 가진 MIMO-OFDMA시스템 성능)

  • Kim, Chan-Kyu
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.4A
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    • pp.303-311
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    • 2011
  • In this paper, we propose the adaptive multibeamforming algorithm to remove the same subcarrier interference and multipath signals in the MIMO(Multi-Input Multi-Out)-OFDMA (Orthogonal Frequency Division Multiplexing Access)system allocated the same subcarrier partially in order to improve spectrum efficiency. In addition to removing the interference, we can get diversity gain and combat the detriment of the performance according to time delay by the proposed approach. BER performance improvement and combating the delay spread detrimental effects of the proposed approach is investigated through computer simulation by applying it to MIMO-OFDMA.

Diversity-Multiplexing Tradeoff Analysis for Half-Duplex Dynamic Decode and Forward Relay MIMO Protocol Using More than Two Source Antennas (두 개 이상의 소스 안테나를 갖는 HD DDF Relay MIMO 프로토콜에 대한 DMT 분석)

  • Kim, Taeyoung;Yim, Changho;Yoon, Eunchul
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38A no.5
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    • pp.436-442
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    • 2013
  • The diversity-multiplexing tradeoff (DMT) function of a special half-duplex (HD) dynamic decode and forward (DDF) relay protocol with more than two antennas at the source node, two antennas at the relay node, and two antennas at the destination node is derived. This protocol is compared to a HD NAF protocol with the same number of source antennas and a HD DDF relay protocol with two antennas at the source node, more than two antennas at the relay node, and two antennas at the destination node.

Implementation of Software Platform for STTC-OFDM based WiBro Systems (STTC-OFDM 기반의 WiBro 시스템 소프트웨어 플랫폼 구현)

  • Lee, Dong-Gi;Lee, Jong-Sik;Jun, Hwang-In;Lee, Seung-Hyun;Kim, Jin-Young
    • 한국정보통신설비학회:학술대회논문집
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    • 2008.08a
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    • pp.535-539
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    • 2008
  • Recently mobile devices can transmit mass data contained multi-media contents. According these flow, a demand for fast data transmission is being risen, so we acutely require remarkable technology that overcome mobile communication's poor environment and rise data transmission volume. Because it can be satisfied these needs, the OFDM(Orthogonal Frequency Division Multiplexing) that rise data transmission volume using efficient frequency, and MIMO(Multiple Input Multiple Output) that rise transmission confidence and data transmission volume using numbers of antenna is attended. Before design of MIMO-OFDM System we want to make an analysis for theory of its systems, and we want to design MIMO-OFDM simulator for verify an ability of modulation, data volume and numbers of antenna.

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An Adaptive Signal Transmission/Reception Scheme for Spectral Efficiency Improvement of Multiple Antenna Systems in Cellular Environments (셀룰러 환경에서 다중 안테나 시스템의 전송 효율 증대를 위한 적응적 송수신 방안)

  • Jin, Gwy-Un;Kim, Seong-Min;Chang, Jae-Won;Sung, Won-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.6C
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    • pp.429-437
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    • 2008
  • Multiple-input multiple-output (MIMO) techniques can be used for the spectral efficiency enhancement of the cellular systems, which can be categorized into spatial multiplexing (SM) and spatial diversity schemes. MIMO systems suffer a severe performance degradation due to the intercell interference from the adjacent cells as the mobile terminal moves toward the cell boundary. Therefore for the spectral efficiency enhancement, an appropriate transmission scheme for the given channel environment and reception scheme which can mitigate the intercell interference are required. In this paper, we propose an adaptive signal transmission/reception scheme for the spectral efficiency improvement of $M_R{\times}M_T$ MIMO systems, present the decision criteria for the adaptive operation of the proposed scheme, and demonstrate the performance gain. The proposed scheme performs adaptive transmission using spatial multiplexing and spatial diversity, and adaptive reception using maximal ratio combining (MRC) and intercell spatial demultiplexing (ISD) when the spatial diversity transmission is used at the transmitter. Spatial multiplexing/demultiplexing is performed at the high signal-to-interference ratio (SIR) range, and the transmit diversity in conjunction with the adaptive reception uses either conventional MRC or ISD which can mitigate the $M_R-1$ interference signals, based on the mobile location. For the performance evaluation of the proposed adaptive scheme, the probability density function (pdf) of the effective SIR for the transmission/reception methods in consideration are derived for $M_R{\times}M_T$ MIMO systems. Using the results, the average effective SIR and spectral efficiency are presented and compared with simulation results.

New Transmit Antenna Selection Schemes for Multipath Environment (다중경로 환경을 위한 새로운 송신 안테나 선택 기법)

  • 임연주;민범석;박상규
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.6A
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    • pp.607-613
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    • 2004
  • The future wireless communication systems will use spatial multiplexing with Multiple Input Multiple Output(MIMO) system to take advantage of high spectral efficiencies. In such systems it will be desirable to select a sub-set of available transmit or receive antennas to reduce cost and complexity. In this paper we propose a novel transmit antenna selection schemes for MIMO systems which is suitable for multipath environment. The proposed transmit antenna selection schemes offer better BER performance than that of MIMO systems without antenna selection and with traditionally proposed antenna selection schemes.

Low-Complexity and Low-Power MIMO Symbol Detector for Mobile Devices with Two TX/RX Antennas

  • Jang, Soohyun;Lee, Seongjoo;Jung, Yunho
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.15 no.2
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    • pp.255-266
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    • 2015
  • In this paper, a low-complexity and low-power soft output multiple input multiple output (MIMO) symbol detector is proposed for mobile devices with two transmit and two receive antennas. The proposed symbol detector can support both the spatial multiplexing mode and spatial diversity mode in single hardware and shows the optimal maximum likelihood (ML) performance. By applying a multi-stage pipeline structure and using a complex multiplier based on the polar-coordinate, the complexity of the proposed architecture is dramatically decreased. Also, by applying a clock-gating scheme to the internal modules for MIMO modes, the power consumption is also reduced. The proposed symbol detector was designed using a hardware description language (HDL) and implemented using a 65nm CMOS standard cell library. With the proposed architecture, the proposed MIMO detector takes up an area of approximately $0.31mm^2$ with 183K equivalent gates and achieves a 150Mbps throughput. Also, the power estimation results show that the proposed MIMO detector can reduce the power consumption by a maximum of 85% for the various test cases.

Adaptive P-SLM Method with New Phase Sequence for PAPR Reduction of MIMO-OFDM Systems (MIMO-OFDM 시스템의 PAPR 감소를 위한 새로운 위상시퀀스의 적응형 P-SLM기법)

  • Yoo, Eun-Ji;Byun, Youn-Shik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.3C
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    • pp.149-156
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    • 2011
  • MIMO-OFDM(Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing) has been spotlighted as a solution of high-quality service for next generation's wireless communications. However, like OFDM, one of main problems of MIMO-OFDM is the high PAPR(Peak-to-Average Power Ratio). In this paper, an adaptive P-SLM(Partitioned-SeLetive Mapping) based on new phase sequence is proposed to reduce PAPR. The proposed method has better performance and lower complexity than conventional method due to the use of periodic multiplication and adaptability by fixed critical PAPR value. Simulation results show that the proposed method has better performance and lower complexity than conventional method.