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2015 4th National Conference on Electrical,Electronics and Computer Engineering(NCEECE 2015)

作者： Li Yu Hou Zemin Zhang Bao-long College of Electrical Engineering Zhengzhou University of Science and Technology College of Information Engineering Zhengzhou University of Science and Technology

ISBN: (纸本)9781510819085

A new adaptive coding and decoding scheme is proposed for distributed space-frequency coding system. Each relay node selects dispersion matrix and modulation type adaptively according to channel state and different detection methods are used according to the threshold of channel condition number adaptively. The MATLAB simulation is performed under COST207 typical urban channel model. Simulation results show that the proposed adaptive coding scheme gives a more good performance.

关键词： Cooperative Communication Distributed Linear Dispersion Codes space-frequency coding condition number Adaptive

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A Novel Radar Waveform Based on space-frequency coding Compatible with Directional Communication

A Novel Radar Waveform Based on Space-frequency Coding Compa...

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CIE International Conference on Radar (RADAR)

作者： Wang, Zhaofeng Liao, Guisheng Yang, Zhiwei Xidian Univ Natl Lab Radar Signal Proc Xian Peoples R China

ISBN: (纸本)9781509048281

This paper presents an integration waveform of radar and communication based on the multi-antenna system. The communication data are emitted by utilizing space-frequency coding on the transmit antenna array. By using beamforming technology in the subarray level, wide area detecting as MIMO (multiple-input-multiple-output) radar and directional communication with the cooperative target in the main lobe can be achieved simultaneously. The simulation results confirm that the signal proposed is able to obtain radar detection capacity and reliable communication.

关键词： space-frequency coding MIMO radar communication

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A space-time coding scheme with maximum diversity gains over frequency-selective fading channels

A space-time coding scheme with maximum diversity gains over...

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14th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications

作者： Chen, SP Yao, TR S Cent Univ Nationalities Dept Elect & Informat Engn Wuhan 430074 Hubei Peoples R China

ISBN: (纸本)7505350668

We introduce a novel space-time coding scheme, called space-time cyclic-delay coding (STCDC), for multiple input multiple output orthogonal frequency-division multiplexing (MIMO-OFDM) systems over frequency-selective fading channels. The scheme exploits the redundancy introduced by channel coding. The transmitter antennas send the cyclically delayed copies of OFDM symbols, and the receiver uses the maximum likelihood estimation method to estimate the transmitted sequence. We show that STCDC-OFDM can achieve the maximum diversity, which is the product of the number of transmitter antennas the number of receiver antennas (N-r) and the channel length (L), if the error control code has at least a free distance of NrL. Compared with the existing space-time coding and space-frequency coded MIMO-OFDM techniques, the proposed scheme has the advantages of being independent from the number of transmit antennas and having a lower implementation complexity.

关键词： cyclic delay coding OFDM diversity space-time coding space-frequency coding

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On the performance of recursive space-frequency codes and iterative decoding in wideband OFDM-MIMO systems: simulated and measured results

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INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 2004年第8期17卷 789-810页

作者： Fletcher, PN McNamara, DP Piechocki, RJ Nix, AR Dean, M QinetiQ Ltd Malvern Worcs England Univ Bristol Ctr Commun Res Bristol BS8 1UB Avon England

In this paper, we study the performance of a bandwidth efficient space-frequency turbo encoding scheme over wideband channels. Results are presented for simulated wideband MIMO channels consisting of two transmit antennas and up to two receive antennas. In addition, wideband channel measurements undertaken with practical multi-element antenna structures at both the access point (AP) and mobile terminal (MT) are presented. Analysis is in terms of channel capacity, 10% channel outage capacity and space-frequency iterative decoding for an IEEE802.11a physical layer complaint modem. It is shown when operating with a spectral efficiency of 1.2 bits/s/Hz, the iterative decoded space-time codes comes within approximately 4.7 dB of 10% outage capacity over Rayleigh fading wideband channels with two transmit and two receive antennas. Over measured channels the iterative decoding scheme performs within 7.7 dB 10% of outage capacity. Losses due to channel state information estimation are also investigated. Copyright (C) 2004 John Wiley Sons, Ltd.

关键词： OFDM space-time coding space-frequency coding iterative decoding MIMO channel capacity

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A Rate-1 space-Time Diversity Method for Rotated 4-QAM Constellations

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WIRELESS PERSONAL COMMUNICATIONS 2012年第2期64卷 211-223页

作者： Hacioglu, Gokce Gangal, Ali Karadeniz Tech Univ Dept Elect & Elect Engn Trabzon Turkey

We propose a rate-1 space-time transmit diversity technique. We obtained second-order diversity by transmitting the real and imaginary parts of the symbols from two antennas. With four transmit antennas, we can add Alamouti coding to reach fourth-order transmit diversity. There is no need to detect symbols jointly in either of these applications. It is possible to use both Alamouti coding and Hadamard spreading diversity with the proposed method, thereby obtaining eighth-order (or even higher) transmit diversity. However, joint detection of the symbols is again required at this point. The proposed technique is a suitable space-frequency coding method for OFDM systems. We used computer simulations to compare our technique with the Alamouti coding, quasi-orthogonal space-time block coding (QOSTBC), and orthogonal space-time block coding (OSTBC) methods. We also compared its performance to that of Hadamard spreading diversity. Alamouti coding performs better than the proposed technique at the second order of transmit diversity, but is also limited to that order. The proposed technique performs better than OSTBC at the same order of the transmit diversity. QOSTBC performs slightly better than the proposed technique at the same order of transmit diversity. However, when all methods have the same detection complexity, the proposed technique performs better than both QOSTBC and Hadamard spreading diversity.

关键词： Diversity space-time coding space-frequency coding Carrier spreading OFDM

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Rate 1 space-time and space-frequency spreading diversity technique

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TURKISH JOURNAL OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCES 2011年第3期19卷 463-482页

作者： Hacioglu, Gokce Gangal, Ali Karadeniz Tech Univ Dept Elect & Elect Engn Trabzon Turkey

In this study, a rate 1 transmitter diversity technique is proposed. The proposed technique uses spreading transform and space-time block coding (STBC) together. space-time, space-frequency, and frequency diversity applications of the proposed technique are shown. The code matrix of the proposed technique can be designed systematically. The proposed technique needs the channel coefficients to stay constant over transmission of 2 rows of the coding matrix regardless of the size of the coding matrix or the diversity order. However, joint detection of the symbols is required for the proposed technique. We used computer simulations to compare our technique with the quasi-orthogonal space-time block coding (QOSTBC), orthogonal space-time block coding (OSTBC), and spreading transform diversity methods. The results showed that the proposed technique provides higher SNR-BER gain than OSTBC and spreading transform diversity, and can provide a higher gain than QOSTBC for time-varying channels. The proposed technique is less sensitive to the time selectivity of the channel than QOSTBC or OSTBC. The detection complexity of the proposed technique is lower than that of spreading diversity.

关键词： Diversity space-time coding space-frequency coding carrier spreading OFDM

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Transmit Beamforming for space-frequency Coded MIMO-OFDM Systems with Spatial Correlation Feedback

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IEEE TRANSACTIONS ON COMMUNICATIONS 2008年第10期56卷 1647-1655页

作者： Sadek, Ahmed K. Su, Weifeng Liu, K. J. Ray Qualcomm Inc Corp R&D San Diego CA 92121 USA SUNY Buffalo Dept Elect Engn Buffalo NY 14260 USA Univ Maryland Dept Elect & Comp Engn College Pk MD 20742 USA Univ Maryland Syst Res Inst College Pk MD 20742 USA

This paper addresses the problem of joint optimization of transmit beamforming and space-frequency (SF) coding for MIMO-OFDM systems with spatial correlation feedback in broadband communications. This problem is challenging in the sense that the transmitter should be designed to beamform across multiple eigenspaces associated with the multipath environment simultaneously. With arbitrary transmit spatial correlation, the performance analysis for SF-coded MIMO-OFDM systems with beamforming is provided, and a general optimization problem for the beamforming design is formulated. Three suboptimal approaches to design the beamformer based on the derived design criteria are proposed i) Eigenvalue selection scheme;ii) Eigenspace selection scheme;and iii) Per-subcarrier approach based on decoding at each subcarrier. The proposed schemes take into account the multiple eigenspace information associated with the multipath-delay channel. Improvement in the performance over SF coding without beamforming is shown through simulations in terms of bit error rate. The Eigenvalue selection scheme provides the best performance among the proposed algorithms. This scheme locates the subspace associated with the largest eigenvalues in the eigenspace of the covariance matrices. With the Eigenvalue selection scheme, the performance improvement is about 3 dB over the SF coding without beamforming for highly correlated channels as shown in our simulations.

关键词： Broadband wireless communications MIMO-OFDM systems transmit beamforming across multiple eigenspaces multiple antennas space-frequency coding correlation feedback

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Noncoherent space-frequency coded MIMO-OFDM

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2005年第9期23卷 1799-1810页

作者： Borgmann, M Bölcskei, H Swiss Fed Inst Technol Commun Technol Lab CH-8092 Zurich Switzerland

Recently, the use of coherent space-frequency coding in orthogonal frequency-division multiplexing (OFDM)-based frequency-selective multiple-input multiple-output (MIMO) fading channels has been proposed. Acquiring knowledge of the fading coefficients in a MIMO channel is already very challenging in the frequency-flat (fast) fading case. In the frequency-selective case, this task becomes significantly more difficult due to the presence of multiple paths, which results in an increased number of parameters to be estimated. In this paper, we address code design for noncoherent frequency-selective MIMO-OFDM fading links, where neither the transmitter nor the receiver knows the channel. We derive the code design criteria, quantify the maximum achievable diversity gain, and provide explicit constructions of full-diversity (space and frequency) achieving codes along with an analytical and numerical performance assessment. We also demonstrate that unlike in the coherent case, noncoherent space-frequency codes designed to achieve full spatial diversity in the frequency-flat fading case can fail completely to exploit not only frequency diversity but also spatial diversity when used in frequency-selective fading environments. We term such codes "catastrophic".

关键词： diversity frequency-selective fading channels multiple-input multiple-output (MIMO) systems noncoherent communications orthogonal frequency-division multiplexing (OFDM) pairwise error probability (PEP) Rayleigh fading space-frequency coding

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space-frequency coded HIPERLAN/2

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IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 2004年第4期50卷 1162-1168页

作者： Esli, C Ozgul, B Delic, H Bogazici Univ Dept Elect & Elect Engn TR-34342 Bebek Istanbul Turkey

This paper attempts to provide an evaluation of High Performance Local Area Network Type 2 (HIPERLAN/2), equipped with space-frequency coded double-antenna transmit diversity. The HIPERLAN/2 physical layer entities are simulated for frequency-selective fading channels for the standard's digital modulation schemes of BPSK, QPSK, 16-QAM and 64-QAM. Protocol data unit (PDU) error rate comparisons of HIPERLAN/2 with and without space frequency coding reveal the potential gains and caveats. The analytical bit error probability calculations confirm that the simulation results are consistent with the theory(1).

关键词： OFDM space-frequency coding transmitter diversity wireless LAN

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Impact of the propagation environment on the performance of space-frequency coded MIMO-OFDM

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2003年第3期21卷 427-439页

作者： Bölcskei, H Borgmann, M Paulraj, AJ Swiss Fed Inst Technol Commun Technol Lab CH-8092 Zurich Switzerland Stanford Univ Dept Elect Engn Informat Syst Lab Stanford CA 94305 USA

Previous work on space-frequency coded multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) has been restricted to idealistic propagation conditions. In this paper, using a broadband MIMO channel model taking into account Ricean K-factor, transmit and receive angle spread, and antenna spacing, we study the impact of the propagation environment on the performance of space-frequency coded MIMO-OFDM. For a given space-frequency code, we quantify the achievable diversity order and coding gain as a function of the propagation parameters. We find that while the presence of spatial receive correlation, affects all space-frequency codes equally, spatial fading correlation at the transmit array can result in widely varying performance losses. High-rate space-frequency codes such as spatial multiplexing are typically significantly more affected by transmit correlation than low-rate codes such as space-frequency block codes. We show that in the MIMO Ricean case the presence of frequency-selectivity typically results in improved performance compared to the frequency-flat case.

关键词： channel modeling diversity multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) space-frequency coding spatial multiplexing

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