• Title/Summary/Keyword: orthogonal space-time block coding (OSTBC)

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Linear Precoding Based on the Imperfect CSI Without Knowing the CSI Reliability (신뢰도를 모르는 불완전한 채널 정보에 기초한 선형 프리코딩)

  • Lee, Woong;Yoon, Eunchul
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.9
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    • pp.1678-1685
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    • 2015
  • We propose a linear precoding scheme combining the merits of beamforming and orthogonal space-time block coding based on the imperfect CSI without knowing the CSI reliability. We first investigate the impact of the CSI reliability on precoding performance by assuming various values of the CSI reliability. Then, we propose a method of predicting the CSI reliability based on the received SNR for the design of an efficient precoder. We show the efficiency of the proposed scheme by simulation.

Block-Ordered Layered Detector for MIMO-STBC Using Joint Eigen-Beamformers and Ad-Hoc Power Discrimination Scheme

  • Lee Won-Cheol
    • Journal of Communications and Networks
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    • v.8 no.3
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    • pp.275-285
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    • 2006
  • Suitable for multi-input multi-output (MIMO) communications, the joint beamforming space-time block coding (JBSTBC) scheme is proposed for high-speed downlink transmission. The major functionality of the scheme entails space-time block encoder and joint transmit and receive eigen-beamformer (EBF) incorporating with block-ordered layered decoder (BOLD), and its operating principle is described in this paper. Within these functionalities, the joint EBFs will be utilized for decorrelating fading channels to cause an enhancement in the spatial diversity gain. Furthermore, to fortify the capability of layered successive interference cancellation (LSIC) in block-ordered layered decoding process, this paper will develop a simple ad-hoc transmit power discrimination scheme (TPDS) based on a particular power discrimination function (PDF). To confirm the superior behavior of the proposed JBSTBC scheme employing ad-hoc TPDS, computer simulations will be conducted under various channel conditions with the provision of detailed mathematical derivations for clarifying its functionality.

New Design for Linear Complex Precoding over ABBA Quasi-Orthogonal Space-Time Block Codes

  • Ran, Rong;Yang, Jang-Hoon;An, Chan-Ho;Kim, Dong-Ku
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.12C
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    • pp.1062-1067
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    • 2008
  • ABBA codes, a class of quasi-orthognal space-time block codes (QoSTBC) proposed by Tirkkonen and others, allow full rate and a fast maximum likelihood (ML) decoding, but do not have full diversity. In this paper, a linear complex precoder is proposed for ABBA codes to achieve full rate and full diversity. Moreover, the same diversity produce as that of orthogonal space-time block code with linear complex precoder (OSTBC-LCP) is achieved. Meanwhile, the size of the linear complex precoder can be reduced by half without affecting performance, which means the same complexity of decoding as that of the conventional ABBA code is guaranteed.

A Simplified Efficient Algorithm for Blind Detection of Orthogonal Space-Time Block Codes

  • Pham, Van Su;Mai, Linh;Lee, Jae-Young;Yoon, Gi-Wan
    • Journal of information and communication convergence engineering
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    • v.6 no.3
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    • pp.261-265
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    • 2008
  • This work presents a simplified efficient blind detection algorithm for orthogonal space-time codes(OSTBC). First, the proposed decoder exploits a proper decomposition approach of the upper triangular matrix R, which resulted from Cholesky-factorization of the composition channel matrix, to form an easy-to-solve blind detection equation. Secondly, in order to avoid suffering from the high computational load, the proposed decoder applies a sub-optimal QR-based decoder. Computer simulation results verify that the proposed decoder allows to significantly reduce computational complexity while still satisfying the bit-error-rate(BER) performance.

Outage Probability Analysis of Multiuser MISO Systems Exploiting Joint Spatial Diversity and Multiuser Diversity with Outdated Feedback

  • Diao, Chunjuan;Xu, Wei;Chen, Ming;Wu, Bingyang
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.5 no.9
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    • pp.1573-1595
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    • 2011
  • In this paper, the outage performance of multiuser multiple-input single-output (MISO) systems exploiting joint spatial and multiuser diversities is investigated for Rayleigh fading channels with outdated feedback. First, we derive closed-form exact outage probabilities for the joint diversity schemes that combine user scheduling with different spatial diversity techniques, including: 1) transmit maximum-ratio combining (TMRC); 2) transmit antenna selection (TAS); and 3) orthogonal space-time block coding (OSTBC). Then the asymptotic outage probabilities are analyzed to gain more insights into the effect of feedback delay. It is observed that with outdated feedback, the asymptotic diversity order of the multiuser OSTBC (M-OSTBC) scheme is equal to the number of transmit antennas at the base station, while that of the multiuser TMRC (M-TMRC) and the multiuser TAS (M-TAS) schemes reduce to one. Further by comparing the asymptotic outage probabilities, it is found that the M-TMRC scheme outperforms the M-TAS scheme, and the M-OSTBC scheme can perform best in the outage regime of practical interest when the feedback delay is large. Theoretical analysis is verified by simulation results.

Novel Approach for Eliminating BER Irreducible Floor in the Enhanced Blind Cyclic Detection for Space-Time Coding

  • Pham, Van-Su;Le, Minh-Tuan;Mai, Linh;Kabir, S.M.Humayun;Yoon, Gi-Wan
    • Journal of information and communication convergence engineering
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    • v.6 no.2
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    • pp.150-153
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    • 2008
  • In the blind Maximum-likelihood (ML) detection for Orthogonal Space-Time Block Codes (OSTBC), the problem of ambiguity in determining the symbols has been a great concern. A possible solution to this problem is to apply semi-blind ML detection, i.e. the blind ML decoding with pilot symbols or training sequence. In order to increase the performance, the number of pilot symbols or length of training sequence should be increased. Unfortunately, this leads to a significantly decrease in system spectral efficiency. This work presents an approach to resolve the aforementioned issue by introducing a new method for constructing transmitted information symbols, in which transmitting information symbols drawn form different modulation constellations. Therefore, the ambiguity can be easily eliminated. In addition, computer simulation is implemented to verify the performance of the proposed approach.

The Interference Nulling using Weighted Precoding in the MIMO Cognitive Radio System (다중 안테나를 사용하는 인지무선 시스템에서 가중치 precoder를 통한 간섭 제거 기법)

  • Lee, Seon-yeong;Sohn, Sung-Hwan;Jang, Sung-Jeen;Kim, Jae-Moung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.8A
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    • pp.768-776
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    • 2010
  • In this paper, we consider a linear precoding for the effective spectrum sharing in multiple-input multiple-output (MIMO) cognitive radio system where a secondary user coexists with primary users. The secondary user employs the orthogonal space time block coding (OSTBC) at the transmitter. Assuming a flat fading channel and a maximum-likelihood receiver, the optimum precoder forces transmission referred to as eigen-beamforming. In this paper, to eliminate the interference, ZF criterion based eigen-beamforming is not only used but also the precoding weight is chosen to cancel the remaining interference. This weight is computed by vector's likelihood. Simulation results show stronger interference suppression capability, better SER performance, and higher capacity than the algorithm in [4].

Performance Analysis of Dual-Hop Cooperative Transmission with Best Relay Selection in a Rayleigh Fading Channel

  • Nessa, Ahasanun;Lee, Woo-Yong;Kim, Yong-Sun;Kwak, Kyung-Sup
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.7A
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    • pp.530-539
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    • 2009
  • Wireless Relaying is a promising solutions to overcome the channel impairments and provides high data rate coverage that appear for beyond 3G mobile communications. In this paper we present end to end BER performance of dual hop wireless communication systems equipped with multiple Decode and Forward relays over Rayleigh fading channel with the best relay selection. We compare the BER performance of the best relay with the BER performance of single relay. We select the best relay based on the end to end channel conditions. We further calculate the outage probability of the best relay. It is shown that the outage probability of the best relay is equivalent to the outage probability when all relays take part in the transmission. We apply Orthogonal Space Time Block coding(OSTBC) at the source terminal. Numerical and simulation results are presented to verify our analysis.