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Efficient algorithm for blind detection of orthogonal space-time block codes

IEEE SIGNAL PROCESSING LETTERS 2007年第5期14卷 301-304页

作者： Le, Minh-Tuan Pham, Van-Su Mai, Linh Yoon, Giwan Informat & Commun Univ Sch Engn Taejon 305714 South Korea

This letter proposes an efficient decoder for signal detection in orthogonal space-time block coded systems employing phase-shift keying modulation without channel state information at the receiver. The proposed decoder consists of a sphere decoder and a QRD-based decoder. Simulation results show that the proposed decoder enables the system to trade off performance improvement against complexity.

关键词： diversity maximum likelihood detection multiple-input multiple-output space-time coding wireless communication

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Hexaferrite slant and slot MIMO antenna element for mobile devices

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2013年第3期55卷 551-554页

作者： Abo, Gavin S. Hong, Yang-Ki Syslo, Ryan Lee, Jaejin Lee, Woncheol Kwon, Hyuck M. Jayasooriya, Chandana K. K. Univ Alabama Dept Elect & Comp Engn Tuscaloosa AL 35487 USA Univ Alabama MINT Ctr Tuscaloosa AL 35487 USA Wichita State Univ Dept Elect Engn & Comp Sci Wichita KS 67260 USA

A hexaferrite slant and slot multiple-input multiple-output antenna with miniature antenna elements was simulated, fabricated, and characterized for antenna performance. Measured return loss and isolation were -33.9/-26.6 dB (for antenna 1/antenna 2) and -18.6 dB at 2.45 GHz, respectively. Measured bandwidth was 454/502 MHz at VSWR < 3. Correlation coefficient between antenna elements calculated from experimental S-parameters was less than 0.00085 between 2.4 and 2.5 GHz. Radiation efficiency of the antennas was measured to be 82% at 2.45 GHz. The antennas have two lobes, omnidirectional, and flower patterns for potential mobile device applications. Simulated and measured antenna performance was found to be in good agreement with each other. (C) 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:551554, 2013;View this article online at ***. DOI 10.1002/mop.27370

关键词： hexaferrite antennas miniaturization multiple-input multiple-output mobile devices

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Magnitude and Wrap-Phase OFDM for MIMO Visible Light Communication Systems

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IEEE COMMUNICATIONS LETTERS 2021年第7期25卷 2324-2328页

作者： Al-Nahhal, Mohamed Basar, Ertugrul Uysal, Murat Ozyegin Univ Dept Elect & Elect Engn TR-34794 Istanbul Turkey Koc Univ Dept Elect & Elect Engn CoreLab TR-34450 Istanbul Turkey

Generalized light emitting diode (LED) index modulation (GLIM) has been proposed as an effective multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) scheme for visible light communications (VLC) systems. In this letter, we propose a magnitude and wrap-phase OFDM (MW-OFDM) scheme for MIMO VLC systems. The proposed MW-OFDM system relies on the conversion of complex signals into polar form with the magnitudes and wrap-phases to decrease the restriction on the number of LEDs compared to the conventional GLIM-OFDM. Furthermore, maximum likelihood and best linear unbiased estimators of the proposed scheme are derived. The proposed MW-OFDM scheme improves the average bit error rate and provides a significant reduction in the decoding complexity, compared to the GLIM-OFDM. Moreover, a half number of LEDs are required for the proposed scheme to deliver the same spectral efficiency in a comparison with the GLIM-OFDM. Numerical results are presented over MIMO VLC channels to elaborate the superiority of our proposed scheme.

关键词： Visible light communications multiple-input multiple-output orthogonal frequency division multiplexing maximum likelihood estimator decoding complexity

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On the Ergodic Mutual Information of Keyhole MIMO Channels With Finite-Alphabet inputs

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IEEE COMMUNICATIONS LETTERS 2023年第1期27卷 90-94页

作者： Ouyang, Chongjun Bereyhi, Ali Asaad, Saba Mueller, Ralf R. Cheng, Julian Yang, Hongwen Beijing Univ Posts & Telecommun Sch Informat & Commun Engn Beijing 100876 Peoples R China Friedrich Alexander Univ Erlangen Nurnberg Inst Digital Commun D-91058 Erlangen Germany Univ British Columbia Sch Engn Kelowna BC V1V 1V7 Canada

This letter studies the ergodic mutual information (EMI) of keyhole multiple-input multiple-output channels having finite-alphabet input signals. The EMI is first investigated for single-stream transmission considering both cases with and without the channel state information at the transmitter. Then, the derived results are extended to the scenario of multi-stream transmission. Asymptotic analyses are performed in the regime of high signal-to-noise ratio (SNR). The high-SNR EMI is shown to converge to a constant with its rate of convergence determined by the diversity order. On this basis, the influence of the keyhole effect on the EMI is discussed. The analytical results are validated by numerical simulations.

关键词： Electromagnetic interference MIMO communication Probability density function Signal to noise ratio Transmitters Mutual information Fading channels Ergodic mutual information finite-alphabet inputs keyhole channel multiple-input multiple-output

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Performance Analysis of Space-Diversity Free-Space Optical Links Over Exponentiated Weibull Channels

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IEEE PHOTONICS TECHNOLOGY LETTERS 2015年第21期27卷 2250-2252页

作者： Jiang, Shuai Yang, Guowei Wei, Yizhen Bi, Meihua Lu, Yang Zhou, Xuefang Hu, Miao Li, Qiliang Hangzhou Dianzi Univ Coll Commun Engn Hangzhou 310018 Zhejiang Peoples R China

We propose a simple analytical method for evaluating the average bit-error rate (BER) performance of multiple input multiple output (MIMO) free-space optical (FSO) communication systems over independent exponentiated Weibull (EW) channels. We first present an accurate approximation to the probability density function (PDF) of the sum of independent EW random variables corresponding to the EW-distributed FSO channel fading. Then, a closed-form expression for the BER of MIMO FSO systems using ON-OFF keying is derived based on the obtained PDF. The proposed method is validated through comparing the BER results obtained by the analytical calculation and the Monte Carlo simulation.

关键词： Free-space optics multiple-input multiple-output exponentiated Weibull distribution Pade approximation average bit error rate

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A RECONFIGURABLE ANTENNA USING TUNING ELEMENT FOR LTE APPLICATIONS

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2015年第3期57卷 556-559页

作者： Lee, Won-Woo Yoon, Cheol LG Elect Mobile Commun Seoul 153802 South Korea

This article is intended to suggest a mobile-embedded antenna with tunable capacitance and the validity of the proposed solution was proved through design, fabrication, and measurement. The aforementioned antenna is applicable to long term evolution (LTE), including band 5, band 8, band 13, and band 17 that are in use today. The 4G mobile services' antennas need to ensure the extension of bandwidth in order to include LTE bands as well as other different services. Low-band characteristics, however, are difficult to achieve mainly because of lack of space for antennas in terminals. The problem may be solved by using a SP4T switch of RFMD, which is to generate the operation frequency of low-band tunable. The optimized parameters were able to fabrication and measure antennas. Hence, antennas come to meet with operation frequency and performance for low bands;also, the performance of the fabricated antenna that has been measured with the optimized parameters has been compared and analyze. (C) 2015 Wiley Periodicals, Inc.

关键词： reconfigurable antenna SP4T long term evolution multiple-input multiple-output

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Hybrid Zero-Forcing Beamforming/Orthogonal Beamforming with User Selection for MIMO Broadcast Channels

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IEEE COMMUNICATIONS LETTERS 2009年第1期13卷 10-12页

作者： Zhang, Caihua Xu, Wei Chen, Ming Southeast Univ Natl Mobile Commun Res Lab Nanjing 210096 Peoples R China

This letter proposes a hybrid transmission scheme by combining zero-forcing beamforming (ZFBF) and orthogonal beamforming (OBF) for the multiple-input multiple-output broadcast channel. This method first utilizes ZFBF for only a part of the scheduled users with approximately orthogonal channels. By further constructing orthogonal beamformers in the null space of the ZFBF user channels, it then employs OBF for the rest of users to fully exploit the spatial dimension. Theoretical analysis, as well as simulation results, verify that our scheme outperforms the conventional ZFBF scheme and OBF scheme with user selection.

关键词： Broadcast channel multiple-input multiple-output zero-forcing beamforming orthogonal beamforming

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COMPARISON OF DIFFERENT MIMO ANTENNA ARRAYS AND USERS' EFFECT ON THEIR PERFORMANCES

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2013年第9期55卷 2039-2043页

作者： Gomez-Calero, Carlos Jamaly, Nima Martinez, Ramon de Haro, Leandro Univ Politecn Madrid Dept Signals Syst & Radiocommun Radiat Grp Madrid Spain Chalmers S-41296 Gothenburg Sweden

multiple-input multiple-output (MIMO) systems have entailed a great enhancement in wireless communications performances. The use of multiple antennas at each side of the radio link has been included in recent drafts and standards such as WLAN, WIMAX, or DVB-T2. The MIMO performances depend on the antenna array characteristics and thus several aspects have to be taken into account to design MIMO antennas. In the literature, many articles can be found in terms of capacity or antenna design, but in this article, different types of antenna arrays for MIMO systems are measured in a reverberation chamber with and without a phantom as a users head. As a result, the MIMO performances are degraded by the user in terms of efficiency, diversity gain, and capacity. Omnidirectional antennas such as monopoles with high radiation efficiency offer the highest performance for a rich scattering nonline of sight indoor environment. (c) 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2039-2043, 2013

关键词： multiple-input multiple-output diversity gain capacity antenna

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Transmit antenna selection for spatial modulation MIMO IoT networks with full-duplex relaying

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AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 2020年 123卷 153312-153312页

作者： Ba Cao Nguyen Tran Manh Hoang Tran, Phuong T. Nguyen, Vinh P. Telecommun Univ Nha Trang Vietnam Ton Duc Thang Univ Fac Elect & Elect Engn Wireless Commun Res Grp Ho Chi Minh City Vietnam Bosch Vietna Co Ltd Long Thanh Vietnam

Recent advances in 5G wireless technology, including multiple-input multiple-output (MIMO) systems and full-duplex communications, have opened the gate for Internet of Things (IoT) applications, especially for wireless sensor nodes to collect and transfer data between environment and control center. This study analyzes the deployment of transmit antenna selection (TAS) in spatial modulation (SM) MIMO full-duplex relaying (FDR) system (SM-MIMO-FDR), where relay uses decode-and-forward (DF) protocol. Due to the computational complexity, TAS was usually neglected in previous studies on SM-MIMO system, especially when FDR is employed in the system. Here, we derive the exact form of outage probability (OP) and symbol error rate (SER) to indicate the performance of SM-MIMO-FDR system with TAS over Rayleigh fading channel. A comparison between SM-MIMO-FDR with TAS and conventional SM-MIMO-FDR shows a significant performance enhancement. Also, this study includes the impact of antenna quantity, data transmission rate, and residual self-interference (RSI) on the OP and SER through derived mathematical expressions. Finally, the correctness of the analysis is verified by numerical results through Monte Carlo simulations. (C) 2020 Elsevier GmbH. All rights reserved. (C) 2020 Elsevier GmbH. All rights reserved.

关键词： Full-duplex relay Self-interference cancellation multiple-input multiple-output Spatial modulation Transmit antenna selection Outage probability Symbol error probability

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Ergodic Capacity of Space-Time Line Code Systems With Transmit Antenna Selection

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2022年第8期71卷 9089-9094页

作者： Lim, Seung-Chan Joung, Jingon Hankyong Natl Univ Sch ICT Robot & Mech Engn Anseong 17579 South Korea Chung Ang Univ Sch Elect & Elect Engn Seoul 06974 South Korea

Since a novel diversity technique called a space-time line code (STLC) was invented, previous studies have focused on the analysis of a rate-1 STLC assuming two receive antennas. For the state-of-the-art STLCs with transmit antenna selection (TAS), in this study, the ergodic capacities of TAS-STLC systems with various code rates are mathematically derived, not only for a TAS-STLC system with two receive antennas but also for those with three or four. To this end, the probability density function of the instantaneous signal-to-noise ratio was characterized. The accuracy of the mathematical analysis was validated by a numerical simulation. This study is significant for investigating the fundamental performance of TAS-STLC systems.

关键词： Receiving antennas Signal to noise ratio Transmitting antennas Codes Three-dimensional displays Probability density function Random variables Ergodic capacity multiple-input multiple-output space-time line code transmit antenna selection

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