• Title/Summary/Keyword: Block Diagonalization

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Novel User Selection Algorithm for MU-MIMO Downlink System with Block Diagonalization (Block Diagonalization을 사용하는 하향링크 시스템에서의 MU-MIMO 사용자 스케쥴링 기법)

  • Kim, Kyunghoon
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.14 no.3
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    • pp.77-85
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    • 2018
  • Multi-User Multiple-Input Multiple-Output (MU-MIMO) is the core technology for improving the channel capacity compared to Single-User MIMO (SU-MIMO) by using multiuser gain and spatial diversity. Key problem for the MU-MIMO is the user selection which is the grouping the users optimally. To solve this problem, we adopt Extreme Value Theory (EVT) at the beginning of the proposed algorithm, which defines a primary user set instead of a single user that has maximum channel power according to a predetermined threshold. Each user in the primary set is then paired with all of the users in the system to define user groups. By comparing these user groups, the group that produces a maximum sum rate can be determined. Through computer simulations, we have found that the proposed method outperforms the conventional technique yielding a sum rate that is 0.81 bps/Hz higher when the transmit signal to noise ratio (SNR) is 30 dB and the total number of users is 100.

Low-Complexity Block Diagonalization Precoder Hardware Implementation for MU-MIMO 4×4

  • Khai, Lam Duc
    • Journal of information and communication convergence engineering
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    • v.17 no.1
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    • pp.1-7
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    • 2019
  • In this paper, we present the block diagonalization (BD) algorithm for the multiple-user multiple input multiple output (MU-MIMO) $4{\times}4$ system using specific purpose processor (SPP) hardware. Our objective is to improve the single-user MIMO (SU-MIMO) system using the MU-MIMO technology, which is remarkably fast and allows more users to connect simultaneously. To that end, our MU-MIMO precoder uses the BD algorithm to ensure signal integrity when connecting multiple users; but remains accurate and stable. However, a precoder that uses the BD algorithm is computationally complex; therefore, we use an SPP with special functions designed to compute the BD algorithm. The implementation test results show that our SPP computes the BD algorithm faster than the software solution.

Channel Quantization for Block Diagonalization with Limited Feedback in Multiuser MIMO Downlink Channels

  • Moon, Sung-Hyun;Lee, Sang-Rim;Kim, Jin-Sung;Lee, Inkyu
    • Journal of Communications and Networks
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    • v.16 no.1
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    • pp.1-9
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    • 2014
  • Block diagonalization (BD) has been proposed as a simple and effective technique in multiuser multiple-input multiple-output (MU-MIMO) broadcast channels. However, when channel state information (CSI) knowledge is limited at the transmitter, the performance of the BD may be degraded because inter-user interference cannot be completely eliminated. In this paper, we propose an efficient CSI quantization technique for BD precoded systems with limited feedback where users supported by a base station are selected by dynamic scheduling. First, we express the received signal-to-interference-plus-noise ratio (SINR) when multiple data streams are transmitted to the user, and derive a lower bound expression of the expected received SINR at each user. Then, based on this measure, each user determines its quantized CSI feedback information which maximizes the derived expected SINR, which comprises both the channel direction and the amplitude information. From simulations, we confirm that the proposed SINR-based channel quantization scheme achieves a significant sum rate gain over the conventional method in practical MU-MIMO systems.

Precoding Algorithm and Capacity of Multiful Antennas Full-duplex Relay (다중 안테나 양방향 릴레이를 위한 프리코딩 기법 및 용량 분석)

  • Seong, Yun-Hyeon;Lee, Jong-ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.10a
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    • pp.481-484
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    • 2009
  • In this paper, we suggest a precoding algorithm for full-duplex relay with multiple antennas. Because full-duplex relay performs transmission and reception at the same time in the same frequency band another existing half-duplex relay differently, self interference arise between transmit and receive antennas of relay. The proposed precoding algorithm eliminates self interference by block diagonalization algorithm and makes the relay perform full-duplex operation. Also we verify that full-duplex relay have improved channel capacity than existing half-duplex relay by computer simulation.

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Modified Block Diagonalization Precoding with Greedy Approach (Greedy 기법을 이용한 수정된 블록 대각화 프리코딩 기법)

  • Kim, Sung-Tae;Seo, Woo-Hyun;Kwak, Kyung-Chul;Hong, Dae-Sik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.1C
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    • pp.79-85
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    • 2008
  • Dirty Paper Coding(DPC) can achieve the sum capacity of a multiuser multiple-input multiple-output(MU MIMO) broadcast channels. However, due to the high computational complexity of the successive encoding and decoding, deploying DPC in real systems is impractical. As one of practical alternatives to DPC, Block Diagonalization(BD) was researched. BD is an extension of the zero-forcing preceding technique that eliminates interuser interference(IUI) in downlink MIMO systems. Though BD has lower complexity than DPC, BD shows poor sum capacity performance. We show that sum capacity performance of BD is degraded due to no IUI constraint. Then, we modify BD to improve its sum capacity performance with relaxing the constraint and sub optimal channel set searching. With simulation results, it can be verified that our modification in BD induces some improvement in sum capacity performance.

Block diagonalization precoding scheme for a multiuser amplify-and-forward MIMO relay system (다중 사용자 증폭재전송 MIMO 중계 시스템을 위한 블록 대각화 기반 프리코딩 기법)

  • Lee, Panhyung;Lee, Jae Hong
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2012.07a
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    • pp.102-103
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    • 2012
  • 본 논문에서는 다중 사용자 증폭재전송(amplify-and-forward) MIMO 중계 시스템을 위한 프리코딩(precoding) 기법을 제안한다. 제안된 프리코딩 기법에서는 블록 대각화(block diagonalization)를 통해 사용자간 간섭(inter-user interfereence)을 제거하고 기지국과 중계기에서의 전송전력(transmit power) 제한을 만족하면서 사용자 데이터 전송률(data rate)의 합이 최대화 되도록 한다. 모의실험결과를 통해 제안된 기법이 기존 기법에 비해 더 높은 사용자 데이터 전송률의 합을 달성함을 보이고 있다.

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Interference Management with Block Diagonalization for Macro/Femto Coexisting Networks

  • Jang, Uk;Cho, Kee-Seong;Ryu, Won;Lee, Ho-Jin
    • ETRI Journal
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    • v.34 no.3
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    • pp.297-307
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    • 2012
  • A femtocell is a small cellular base station, typically designed for use in a home or small business. The random deployment of a femtocell has a critical effect on the performance of a macrocell network due to co-channel interference. Utilizing the advantage of a multiple-input multiple-output system, each femto base station (FBS) is able to form a cluster and generates a precoding matrix, which is a modified version of conventional single-cell block diagonalization, in a cooperative manner. Since interference from clustered-FBSs located at the nearby macro user equipment (MUE) is the dominant interference contributor to the coexisting networks, each cluster generates a precoding matrix considering the effects of interference on nearby MUEs. Through simulation, we verify that the proposed algorithm shows better performance respective to both MUE and femto user equipment, in terms of capacity.

A Review of Fixed-Complexity Vector Perturbation for MU-MIMO

  • Mohaisen, Manar
    • Journal of Information Processing Systems
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    • v.11 no.3
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    • pp.354-369
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    • 2015
  • Recently, there has been an increasing demand of high data rates services, where several multiuser multiple-input multiple-output (MU-MIMO) techniques were introduced to meet these demands. Among these techniques, vector perturbation combined with linear precoding techniques, such as zero-forcing and minimum mean-square error, have been proven to be efficient in reducing the transmit power and hence, perform close to the optimum algorithm. In this paper, we review several fixed-complexity vector perturbation techniques and investigate their performance under both perfect and imperfect channel knowledge at the transmitter. Also, we investigate the combination of block diagonalization with vector perturbation outline its merits.

Hierarchical optimal control of decentralized discrete-time system for process automation (분산 이산시간 시스템의 공정 자동화를 위한 계층적 최적제어)

  • 김현기;전기준
    • 제어로봇시스템학회:학술대회논문집
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    • 1987.10b
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    • pp.209-213
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    • 1987
  • This paper presents decentralized discrete-time system which is optimized by hierarchical control for process automation via the extended interaction balance method. This proposed method can control general matrix which input matrix is not block diagonalization. Also, this paper shows convergence condition of proposed method.

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Performance of Multi-User MIMO/OFDM System using Cyclic Delay Diversity for Fading Channels (페이딩 채널에서 순환 지연 다이버시티를 적용한 다중 사용자 MIMO OFDM 시스템의 성능)

  • Park, In-Hwan;Kim, Yoon-Hyun;Kim, Jin-Young
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.10 no.6
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    • pp.263-268
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    • 2010
  • As the demand of high quality service in next generation wireless communication systems, a high performance of data transmission requires an increase of spectrum efficiency and an improvement of error performance in wireless communication systems. In this paper, we propose a multi-user multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system with cyclic delay diversity and block diagonalization procoding method to improve bit error rate (BER) performance with wireless local area network (WLAN) channel model C and D for 802.11n WLAN system. The results of mathlab simulation show the improvement of BER performance in 802.11n wireless indoor channel environment.