• Title/Summary/Keyword: ZF detector

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Error Performance of Spatial-temporal Combining-based Spatial Multiplexing UWB Systems Using Transmit Antenna Selection

  • Kim, Sang-Choon
    • Journal of information and communication convergence engineering
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    • v.10 no.3
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    • pp.215-219
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    • 2012
  • This paper applies transmit antenna selection algorithms to spatial-temporal combining-based spatial multiplexing (SM) ultra-wideband (UWB) systems. The employed criterion is based on the largest minimum output signal-to-noise ratio of the multiplexed streams. It is shown via simulations that the bit error rate (BER) performance of the SM UWB systems based on the two-dimensional Rake receiver is significantly improved by antenna diversity through transmit antenna selection on a log-normal multipath fading channel. When the transmit antenna diversity through antenna selection is exploited in the SM UWB systems, the BER performance of the spatial-temporal combining-based zero-forcing (ZF) receiver is also compared with that of the ZF detector followed by the Rake receiver.

A Hybrid Detection Technique for Multiple Input Multiple Output Systems in Fading Environment (감쇄 환경에서 여러 입력 여러 출력 시스템에 알맞은 혼합 검파 방식)

  • Oh Jong-Ho;An Tae-Hun;Song Iick-Ho;Park Ju-Ho;Park So-Ryoung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.9C
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    • pp.897-904
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    • 2006
  • Multiple input multiple output architectures, known to provide high spectral efficiencies, can provide the best performance in terms of the block error rate when a maximum likelihood (ML) detector is employed. The complexity of the ML detector, however, increases exponentially with the numbers of transmit antennas and signals in the constellation. The zero forcing (ZF) detector has been suggested as a reduced-complexity detection method at the cost of performance degradation. In order to improve the performance of the ZF detector while reducing the complexity of the ML detector, we propose a novel multistage decision method. Numerical results show that, despite the proposed detector has a lower complexity than the ML detector, the performance difference between the ML and proposed detectors is negligibly small at high SNR.

Low Complexity ML Detection Based on Linear Detectors in MIMO Systems

  • Niyizamwiyitira, Christine;Kang, Chul-Gyu;Oh, Chang-Heon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.10a
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    • pp.506-509
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    • 2009
  • This paper studies about reducing the complexity of ML detection in MIMO/V-blast system, based on MMSE and ZF linear detectors. Beforehand, the receiver detects the signal using the linear detector such as ZF or MMSE. Moreover, the next step is to assess whether the signal is reliable or not by verifying the reliability condition, if the latter is reliable then it is the output if not it has to be detected by the advanced detector until the reliability condition is verified.

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Performance Analysis of LR-aided ZF Receiver for MIMO Systems

  • Kim, Sangchoon
    • International journal of advanced smart convergence
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    • v.7 no.3
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    • pp.37-43
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    • 2018
  • Lattice-reduction (LR) techniques have been developed for signal detection in spatial multiplexing multiple input multiple output (MIMO) systems to obtain the largest diversity gain. Thus, an LR-assisted zero-forcing (ZF) receiver can achieve the maximum diversity gain in spatial multiplexing MIMO systems. In this paper, a simplified analysis of the achievable diversity gain is presented by fitting the channel coefficients lattice-reduced by a complex Lenstra-Lenstra-$Lov{\acute{a}}z$ (LLL) algorithm into approximated Gaussian random variables. It will be shown that the maximum diversity gain corresponding to two times the number of receive antennas can be achieved by the LR-based ZF detector. In addition, the approximated bit error rate (BER) expression is also derived. Finally, the analytical BER performance is comparatively studied with the simulated results.

Performance Analysis of MIMO Detection in Frequency Selective Rayleigh Fading Channels (주파수 선택적 Rayleigh 페이딩 채널에서의 MIMO 검출 성능 연구)

  • An, Jin-Young;Kim, Sang-Choon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.5
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    • pp.974-979
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    • 2009
  • The BER performance of a MIMO detection scheme on frequency selective Rayleigh fading channels is analytically discussed. The presented MIMO detection scheme consists of temporal and spatial combiners followed by a ZF detector. It is shown that for a MIMO system with $N_T$ transmit antennas, $N_R$ receive antennas, and L resolvable multipath components, it achieves the diversity order of $LN_R-N_T+1$. In frequency selective Rayleigh fading channels, an analytical error rate expression of the systems is also provided and the analytical error performance is compared with the simulated results.

MIMO Receiver Using RBF Network Over Rich-Scattering fading channels (Rich-Scattering 페이딩 채널에서 RBF Network를 이용한 MIMO 수신기)

  • 고균병;강창언;홍대식
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.40 no.8
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    • pp.301-306
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    • 2003
  • This paper proposes a novel detection scheme using a radial basis function (RBF) network in a multi-input multi-output (MIMO) environment. In order to evaluate the performance of the proposed MIMO-RBF receiver, simulations are performed over the rich-scattering fading channel. Simulation results confirm that the proposed scheme shows the similar bit-error rate (BER) performance of a maximum likelihood detection (MLD) and outperforms Vertical-Bell Laboratories Layered Space-Time using minimum-mean-square-error nulling (VBLAST-MMSE) as well as VBLAST using zero-forcing nulling (VBLAST-ZF). Moreover, we investigate the effect on the performance of the number of RBF center with two modulation formats (BPSK and QPSK) and different number of transmit and receive antennas. The performance of the proposed detector is verified with respect to an initialization-rate of RBF centers.

Zero forcing based sphere decoder for generalized spatial modulation systems

  • Jafarpoor, Sara;Fouladian, Majid;Neinavaie, Mohammad
    • ETRI Journal
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    • v.41 no.2
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    • pp.145-159
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    • 2019
  • To reduce the number of radio frequency (RF) chains in multiple input multiple output (MIMO) systems, generalized spatial modulation (GSM) techniques have been proposed in the literature. In this paper, we propose a zero-forcing (ZF)-based detector, which performs an initial pruning of the search tree that will be considered as the initial condition in a sphere decoding (SD) algorithm. The proposed method significantly reduces the computational complexity of GSM systems while achieving a near maximum likelihood (ML) performance. We analyze the performance of the proposed method and provide an analytic performance difference between the proposed method and the ML detector. Simulation results show that the performance of the proposed method is very close to that of the ML detector, while achieving a significant computational complexity reduction in comparison with the conventional SD method, in terms of the number of visited nodes. We also present some simulations to assess the accuracy of our theoretical results.

Lattice-Reduction-Aided Detection based Extended Noise Variance Matrix using Semidefinite Relaxation in MIMO Systems (MIMO시스템에서 Semidefinite Relaxation을 이용한 잡음 분산 행렬 기반의 Lattice-Reduction-Aided 검출기)

  • Lee, Dong-Jin;Park, Su-Bin;Byun, Youn-Shik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.11C
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    • pp.932-939
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    • 2008
  • Recently lattice-reduction (LR) has been used in signal detection for multiple-input multiple-output (MIMO) systems. The conventional LR aided detection schemes are combinations of LR and signal detection methods such as zero-forcing (ZF) and minimum mean square error (MMSE) detection. In this paper, we propose the Lattice-Reduction-aided scheme based on extended noise variance matrix to search good candidate symbol set in quantization step. Then this scheme estimates transmitted symbol with Semidefinite Relaxation by candidate symbol set. Simulation results in a random MIMO system show that the proposed scheme exhibits improved performance and a slight increase in complexity.

A Low Complexity Candidate List Generation for MIMO Iterative Receiver via Hierarchically Modulated Property (MIMO Iterative 수신기에서 계층적 변조 특성을 이용한 낮은 복잡도를 가지는 후보 리스트 발생 기법)

  • Jeon, Eun-Sung;Yang, Jang-Hoon;Kim, Dong-Ku
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.6A
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    • pp.500-505
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    • 2009
  • In this paper, We present a low complexity candidate list generation scheme in iterative MIMO receiver. Since QAM modulation can be decomposed into HP symbols and LP symbol and HP symbol is robust in error capability, we generate HP symbol list with simple ZF detector output and its corresponding neighbor HP symbols, Then, based on HP symbol list, the LP symbol list is generated by using the sphere decoder. From the second iteration, since apriori value from channel decoder is available, the candidate list is updated based on demodulated apriori value. Through the simulation, we observe that at the first iteration, the BER performance is worse than LSD. However, as the number of iteration is increased, the proposed scheme has almost same performance as LSD. Moreover, the proposed one has reduced candidate list generation time and lower number of candidate list compared with LSD.

A Receive Diversity Combining Technique for SC-PDMA-based Cooperative Relays (SC-FDMA 기반 상호협력 릴레이를 위한 수신 다이버시터 결합 기법)

  • Woo, Kyung-Soo;Kim, Yeong-Jun;Yoo, Hyun-Il;Kim, Jae-Kwon;Yun, Sang-Boh;Cho, Yong-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.4A
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    • pp.302-308
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    • 2009
  • In this paper, two receive diversity combining techniques are proposed for single-carrier Sequency division multiple access (SC-FDMA)-based cooperative relay systems when DFT spreading sizes for mobile station (MS) and relay station (RS) are different. A simplified-MRC (5-MRC) technique performs diversity combining in the time domain using the estimated channel weight and initial values obtained by SC-FDMA signal detection. An interference rejection-MRC (IR-MRC) technique performs diversity combining in the frequency domain by adjusting DFT spreading size in the receiver. It is shown by computer simulation that the proposed receive diversity combining techniques achieve a significant performance gain over the conventional MRC technique with zero forcing (ZF) detector.