• Title/Summary/Keyword: 다중입출력 안테나

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Performance Analysis of Multiuser MIMO Systems with Zero Forcing Receivers (Zero Forcing 수신기를 결합한 다중사용자 다중안테나 시스템의 성능 분석)

  • Sung, Chang-Kyung;Moon, Sung-Hyun;Park, Eun-Sung;Lee, In-Kyu
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.8A
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    • pp.592-599
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    • 2009
  • In this paper, we consider multiuser multi-input/multi-output antenna systems with zero-forcing receivers in downlink. In this case, to exploit multiuser diversity, spatial-division multiple access (SDMA) system allows to assign different users to a part of transmit antennas at the base station whereas spatial-division multiplexing (SDM) system assigns all antennas to single user's data stream. In this paper, we present analytical frameworks to evaluate performance of these systems. We first analyze the performance of these two systems by deriving closed-form expressions of achievable throughput. Numerical results show that the derived expressions are very tight. In addition, we approximate the capacity expression of SDM and SDMA systems and compare the SDM with the optimal case.

A signal Detection Technique based on Compressed Sensing for Full-Duplex Generalized Spatial Modulation Systems (전 이중방식 일반화된 공간변조 시스템을 위한 압축센싱기반 신호검출기법)

  • Park, Jeonghong;Ban, Tae-Won;Jung, Bang Chul
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.05a
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    • pp.43-46
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    • 2015
  • Recently, full-duplex communications has been considered as one of the most promising techniques for net-generation mobile communication system. In this paper, we propose a compressed sensing based signal detection technique for full-duplex generalized spatial modulation (FD-GSM) systems. In FD-GSM systems, some antennas are used for signal transmission according to input data and the otehrs are used for detecting signals received over the same frequency band. The self-interference (SI) is assumed to be completely removed by help for the recently proposed SI cancellation techniques. The proposed signal detection technique significantly outperforms the conventional ones in terms of symbol error rate (SER). We will investigate the optimal number of used antennas in FD-GSM systems.

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Performance Evaluation of Turbo Codes by Soft Detection Metrics of STBC over an IEEE 802.16e Link (IEEE 802.16e 링크에서 시공간 블록 부호의 연판정 검출에 따른 터보 부호의 성능평가)

  • Kim, Young-Min;Kim, Soo-Young;Lim, Kwang-Jae
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.47 no.2
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    • pp.1-8
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    • 2010
  • Multi antenna techniques using space-time codes can achieve diversity gains in a multi-path environment without additional bandwidth requirement. Most of the 4G candidate standards including the IEEE 802.16e adopt multi-input multi-output (MIMO) schemes to achieve either high throughput performance or diversity gains. In these 4G candidate standards, turbo codes using an iterative decoder with soft input soft output are used to overcome serious channel fading. For this reason, the estimated signal values from MIMO detectors should be soft decision detection values. In this paper, we propose efficient methods to estimate soft decision detection values for various space time coding schemes, and provide the simulation results of turbo coded space time coding scheme over an IEEE 802.16e link.

MMSE Based Nonlinear Precoding for Multiuser MIMO Broadcast Channels with Inter-Cell Interference (다중사용자 다중입출력 하향링크 채널에서 인접셀 간섭을 고려한 MMSE 기반 비선형 프리코딩)

  • Lee, Kyoung-Jae;Sung, Hakjea;Lee, Inkyu
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.8
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    • pp.896-902
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    • 2016
  • In this paper, we investigate a minimum mean-squared error based nonlinear successive precoding method as a practical solution of dirty paper coding for multiuser downlink channels where each user has more than one antenna in the presence of other cell interference (OCI). Unlike conventional zero-forcing (ZF) based methods, the proposed scheme takes the OCI plus noise into account when suppressing the inter-cell multiuser interference, which results in improvement of the received signal-to-interference-plus-noise ratio. Simulation results show that the proposed scheme outperforms conventional methods in terms of sum rate for various OCI configurations.

Multi-antenna Subcarrier Allocation Using Zero-Forcing Beamforming in MIMO-OFDM Systems (다중입출력 직교 주파수 분할 다중접속 시스템에서 제로포싱 빔형성을 이용한 다중안테나 부반송파 할당 방법)

  • Shin, Young-Il;Kang, Tae-Sung;Kim, Hyung-Myung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.10A
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    • pp.974-983
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    • 2007
  • In this paper, a low complexity subcarrier allocation scheme is proposed for multiuser MIMO-OFDM systems with zero-forcing beamformer (ZFBF) so that the total transmit power can be minimized satisfying given target data rate. Since the optimal method requires very high computational complexity, we propose a low complextiy suboptimal method. Using the fact that the effective channel gain is proportional to the orthogonallity of channels of multiplexed users, a user set with the highest orthogonality of channel among users is assigned to each subcarrier in order to minimize required transmit power. The numerical results show that the proposed suboptimal method can reduce computational complexity with little performance loss.

Hybrid Precoder Design for Massive MIMO Systems with OSA structure (부분 중첩 안테나 배열 구조를 갖는 대용량 MIMO 시스템을 위한 하이브리드 프리코더 설계)

  • Seo, Bangwon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.25 no.2
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    • pp.274-279
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    • 2021
  • Since conventional massive antenna systems require too many RF chains, they have disadvantages of high implementation cost and complexity. To overcome this problem, hybrid precoding schemes have been proposed. But, they are still of high implementation cost and complexity because RF chains are connected to all antenna elements. In this paper, we consider massive MIMO systems with overlapped sub-array (OSA) structure and then, propose a hybrid precoding scheme. In the overlapped subarray structure, RF analog precoding matrix has a sparse structure where many elements of RF analog precoding matrix are zeros. Using this sparse property, we propose a GTP-based precoder design method for RF and baseband digital precoding. Through simulation, we show that the proposed scheme has more than 85% of the spectral efficiency of the fully-connected structure while having 20~30% of complexity of it.

Two-Way MIMO AF Relaying Methods Having a Legacy Device without Self-Interference Cancellation (자기간섭 제거 기능이 없는 기존 단말을 가지는 양방향 다중입출력 중계 증폭 전송 기법)

  • Lee, Kyoung-Jae
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.42 no.2
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    • pp.338-344
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    • 2017
  • In this paper, two-way amplify-and-forward relay methods are investigated where two terminals and one relay node are equipped with multiple antennas. In two-way relay channels, it is assumed that one terminal can eliminate its own self-interference but the other cannot. For this channel, we first maximize the sum-rate performance by employing an iterative gradient descent (GD) algorithm. Then, a simple singular value decomposition (SVD) based block triangularization is developed to null the self-interference. Simulation results show the proposed methods outperform the conventional schemes for various environments.

Performance Analysis of Fading Avoidance Scheme using Cooperative Spectrum Sensing Technique (협력 스펙트럼 감지 기법을 이용한 페이딩 회피 방안에 대한 성능 분석)

  • Kim, Tae-Wook;Kong, Hyung-Yun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.14 no.5
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    • pp.61-65
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    • 2014
  • In this paper, we propose a method using cooperative spectrum sensing to avoid multipath and frequency selective fading. One of methods in conventional scheme was multi input multi output (MIMO) solution. However, in the wireless environment, mobile device hardly supports multi antenna because of limitation of hardware. Motivated from above problems, the proposed method provides the information of excellent channel to transmitter. As a result, quality of service (QoS) required by users can be satisfied. Finally, performance of the proposed protocol is analyzed in term of bit error rate (BER).

Video-Aware Prioritized Network Coding over MIMO Relay Networks (MIMO 릴레이 네트워크에서 비디오 적응적인 중요도 인지 네트워크 코딩)

  • Yoon, Jisun;Ahn, Chunsoo;Shin, Jitae
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37A no.9
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    • pp.746-752
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    • 2012
  • SVC layered video is consists of a Base Layer (BL) and Enhancement Layer (EL). Without the base layer decoding, the higher EL layer can not be decoded. Therefore, successful transfer of the BL is important factor for improving the SVC video data. In this paper, we propose a network coding of layered video to improve success decoding probability with the importance order of the video data over a multi-relay system. We shows that formula analysis and experimental results of the proposed network coding scheme. In addition, we shows performance of video quality according to the number of relays.

A Channel Estimation Method by Orthogonalizing of the time domain training signals in MIMO-OFDM systems (MIMO-OFDM 시스템에서 시간영역 훈련신호들의 직교화를 통한채널추정 방법)

  • Jeon, Hyoung-Goo
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.12
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    • pp.2818-2825
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    • 2013
  • In this paper, a channel estimation method by orthogonalizing of the time domain training signal in MIMO-OFDM systems is proposed. It has shown that Jeon's method[8] cannot be directly used in 4 Tx antenna MIMO-OFDM systems since the delayed Rx signals interfere the orthogonal property of the time domain training signals. As a possible solution to the problem, in this paper, a guard interval is inserted into the center of the training signals so that the orthogonal property between the Rx training signals can be maintained. It is shown by using computer simulations that the proposed method can estimate the channel response in time domain in 4 Tx antenna MIMO-OFDM systems.