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Generalized Selection Combining Scheme for Orthogonal Space-Time Block Codes with M-QAM and M-PAM Modulation Schemes

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WIRELESS PERSONAL COMMUNICATIONS 2017年第3期94卷 1619-1641页

作者： Bhaskar, Vidhyacharan Kandpal, Divya San Francisco State Univ Dept Elect & Comp Engn 1600 Holloway Ave San Francisco CA 94132 USA Northwestern Polytech Univ Dept Elect Engn 47650 Westinghouse Dr Fremont CA 94539 USA SRM Univ Dept Elect & Commun Engn Kattankulathur 603203 Tamil Nadu India

multiple-input multiple-output (MIMO) systems implement multiple antennas to enhance diversity gain of wireless communication systems. Earlier work in generalized selection combining (GSC) focused on single-input multiple-output systems without space-time coding. Recently, with the aid of space-time coding, diversity gain became possible using multiple transmit antennas. In this paper, GSC scheme is applied to orthogonal space-time block codes (OSTBC) for 4 x L and 8 x L MIMO systems with various modulation schemes like M-PSK, M-QAM, and M-PAM in a slowly fading Rayleigh channel. The performance of GSC for half rate-full diversity, full rate-full diversity, and 3/4 rate-full diversity OSTBC is discussed and compared. Approximate closed-form expressions for symbol error rate (SER) and ergodic capacity for various OSTBCs are derived. The impact of channel estimation errors on system performance is also examined. Approximate closed-form expressions for performance bounds on SER and ergodic capacity of GSC for MIMO OSTBC are also derived and plotted.

关键词： multiple-input multiple-output Generalized selection combining Maximal ratio combining Alamouti scheme Orthogonal space-time block code Half rate and full rate diversity

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Spectral-Efficient Generalized Spatial Modulation Based Hybrid Dimming Scheme With LACO-OFDM in VLC

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IEEE ACCESS 2018年 6卷 41153-41162页

作者： Wang, Tengjiao Yang, Fang Cheng, Ling Song, Jian Tsinghua Univ Beijing Natl Res Ctr Informat Sci & Technol Dept Elect Engn Beijing 100084 Peoples R China Tsinghua Univ Shenzhen Res Inst Key Lab Digital TV Syst Guangdong Prov & Shenzhen Shenzhen 518057 Peoples R China Univ Witwatersrand Sch Elect & Informat Engn ZA-2000 Johannesburg South Africa

Visible light communication (VLC) is regarded as one of the promising candidates to complement the conventional radio frequency communication as it can potentially perform communication and illumination simultaneously. Recently, VLC is combined with the generalized spatial modulation (GenSM) technology to improve spectral and energy efficiencies. In order to provide high-speed communication and flexible dimming control simultaneously, in this paper, a spectral-efficient GenSM-based hybrid dimming scheme with layered asymmetrically clipped optical OFDM is proposed for VLC, which combines the spatial-domain and time-domain dimming strategies. The channel capacities of the proposed scheme are analyzed and the closed-form expressions of the channel capacity are derived in both the rich scattering scenario and highly correlated scenario. According to the required illumination level, the spatial-domain and time-domain strategies are realized based on the maximization of the channel capacity. Simulation results substantiate the superior performance of the proposed dimming scheme over the state-of-art dimming schemes.

关键词： Channel capacity optimization generalized spatial modulation hybrid dimming control multiple-input multiple-output visible light communication

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On the Convenience of Perfect Channel Knowledge for Spatial Equalization of Correlated MIMO-VLC Links: Is it Really Worth it?

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2022年第18期40卷 6101-6115页

作者： Petroni, Andrea Biagi, Mauro Univ Roma La Sapienza Dept Informat Engn Elect & Telecommun DIET I-00184 Rome RM Italy

Visible Light Communication has risen as a promising technology to support indoor wireless connectivity and provide illumination services as well. Moreover, high communication performance can be achieved by implementing multiple-input multiple-output architectures. However, the crosstalk characterizing spatially correlated channels scenarios may significantly impact on reliability. Such issue is commonly addressed by means of spatial equalization, with zero forcing and minimum mean square error representing the most widespread approaches. These methods allow the mitigation of crosstalk, even though they may cause undesired noise amplification as side effect, inducing errors during signal detection and decoding. In this regard, by focusing on a more realistic approach with respect to the literature, this work overturns the belief that having perfect channel knowledge is always better. Hence, we show that, when applying spatial equalization, imperfect channel knowledge is sometimes preferable to ideal channel state information. As a result, noise amplification is reduced at the expense of a reasonably less accurate crosstalk mitigation, with better communication performance being achieved.

关键词： Channels correlation multiple-input multiple-output spatial equalization visible light communication

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On the performance of asynchronous ad-hoc networks using interference alignment with renewal process

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IET COMMUNICATIONS 2013年第15期7卷 1628-1637页

作者： Luo, Yi Du, Huiqin Xue, J. Ratnarajah, Tharm Wilcox, Dave Univ Edinburgh Sch Engn & Elect Inst Digital Commun Edinburgh EH9 3JL Midlothian Scotland Camlin Technol Lisburn BT28 2EX North Ireland

The performance of ad-hoc networks is greatly affected by interference, particularly interference from nearby nodes. Based on stochastic geometry, this work studies a form of multiple-input-multiple-output (interference alignment (IA) that eliminates interference from transmitters within a range and treats the remaining interference as a shot noise process. Adapting to the bursty nature of ad-hoc network traffic, the authors introduce a novel distributed ad-hoc network with renewal process, whereby cooperation between interferer and receiver is implemented in one-way process, which results from the difficulties for the node to change the beamforming or receiving matrix whereas communicating with a proposed transmitter. In addition, this scheme takes advantage of IA, leaving the desired signal with higher degree of freedom (DoF) compared with the partially zero-forcing method. Outage probability and transmission capacity are derived with and without Rayleigh fading. Simulation results show the effect of IA in ad-hoc network, including the incremental in the DoF of the desired signal as time goes by. Monte Carlo simulations are implemented and show that IA outperforms successive interference cancellation by at least 10 dB in terms of the signal-to-interference ratio with large path-loss exponent.

关键词： ad hoc networks interference (signal) Monte Carlo methods radio receivers radio transmitters Rayleigh channels telecommunication traffic asynchronous ad-hoc networks interference alignment renewal process stochastic geometry multiple-input multiple-output shot noise process ad-hoc network traffic distributed ad-hoc network renewal process interferer receiver receiving matrix beamforming transmitter degree of freedom partially zero-forcing method transmission capacity Rayleigh fading Monte Carlo simulations interference cancellation signal-to-interference ratio large path-loss exponent

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STBC-Enabled Secure Wireless Transmission With Cooperative Devices Under Imperfect CSI of Destination

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IEEE ACCESS 2023年 11卷 46804-46819页

作者： Shen, Tianji Hama, Yuto Ochiai, Hideki Yokohama Natl Univ Dept Elect & Comp Engn Yokohama 2408501 Japan

In this work, we investigate a practical secure multiple-input single-output (MISO) wireless transmission of information from a source to a destination assisted by cooperative devices. In the first phase, a space-time block code (STBC) is employed;thus, the source does not require any channel state information (CSI). In the second phase, the cooperative devices are divided into two groups, depending on whether they serve for relaying or jamming. Based on the imperfect CSI toward the destination, the devices allocated to the relay group assist the source in forwarding information, whereas those within the jamming group send artificial noise (AN) so as to prevent the eavesdropper from receiving information. Furthermore, the system utilizes two grouping strategies, referred to as random and adaptive. In the former case the role (relaying or jamming) of each device is predetermined randomly, whereas in the latter case it is determined autonomously depending on the decoding results. We analyze the outage probability of our proposed system with and without power allocation optimization under the assumption of imperfect CSI at the cooperative devices, and their accuracy is verified by Monte-Carlo simulations.

关键词： Jamming Wireless communication Relays MIMO communication Communication system security Interference Power system reliability Channel state information jamming multiple-input multiple-output physical-layer security selective relaying space-time block code

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A Survey on Hybrid, 3D, Interference Mitigation and Secure Data Beamforming Techniques for 5G System

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WIRELESS PERSONAL COMMUNICATIONS 2020年第1期114卷 883-900页

作者： Yadav, Ranjeet Tripathi, Ashutosh Amity Univ Rajasthan Amity Sch Engn & Technol Dept ECE Jaipur Rajasthan India

By 2020 world will testimony new archaic Multi-antenna technologies like beamforming along with massive multiple-input multiple-output in 5G system. The cellular networks with 5th Generation (5G) are introduced with the determined aim of supporting a very heterogeneous service mixture, everyone with its individual detailed requirements. It largely leverages a very huge count of independently controllable antennas at the BS, and thereby attains greater enhancement regarding the energy and spectral efficiency. This paper elucidate about the Hybrid Beamforming techniques, 3D beamforming techniques, Interference mitigation between small and macro cell beamforming proficiency and secure data transmission pre-owned in beamforming technologies dispense a comprehensive analysis of all aspect of Beamforming technologies used in 5G systems.

关键词： multiple-input multiple-output 5G systems Beamforming Long term evolution Wireless communication

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Efficient QR-Based Multi-Mode Precoding for Limited Feedback Multi-User MIMO Systems

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WIRELESS PERSONAL COMMUNICATIONS 2014年第2期74卷 969-987页

作者： Pan, Chien-Hung Lee, Ta-Sung Natl Chiao Tung Univ Dept Elect Engn Hsinchu Taiwan

This paper proposes QR-based criteria for efficient selection of multi-mode precoders in multi-user multiple-input multiple-output (MU-MIMO) precoded systems with a limited feedback. In particular, a MU-MIMO QR based precoding scheme is developed which takes advantage of the overall precoder design among users in conjunction with QR detection. A selection criterion is developed to identify the precoder that yields the maximum free distance. Efficient mode selection and tree search strategies are adopted to reduce the complexity associated with the identification of the optimum precoder. To further improve the detection performance in correlated channels, an efficient QR-based MMSE V-BLAST detector is proposed. Computer simulations confirm that the proposed QR-based precoding scheme attains the performance of existing schemes with a significantly lower complexity level.

关键词： QR decomposition Multi-mode precoding multiple-input multiple-output Limited feedback system

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Dual-band mimo rectangular dielectric resonator antenna with high port isolation for LTE applications

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2017年第1期59卷 44-49页

作者： Khan, Aftab Ahmad Khan, Rizwan Aqeel, Sajid Kazim, Jalil Ur Rehman Saleem, Jawad Owais, M. K. COMSATS Inst Informat Technol Dept Elect Engn Abbottabad Kpk Pakistan

A novel dual-band dual-polarized rectangular dielectric resonator antennas (DRA) for long term evolution (LTE) is described and fabricated. It covers LTE band 11 (1.43-1.50) GHz at low frequency and LTE band 7 (2.50-2.69) GHz at high frequency. The isolation between two antenna ports is more than 23 dB and 32 dB at 1.45 GHz and 2.6 GHz respectively. A u-shaped and a rectangular ground planes have been used above and below the substrate to achieve high isolation. DRA is excited through a coaxial probe and a rectangular slot. The proposed antenna can transmit and receive information independently using fundamental modes of DRA. Scalable behavior and frequency ratio has also been investigated in this work Results of Co and Cross-polarization, envelop correlation coefficient and diversity shows that the proposed design is suitable for MIMO LTE applications. (c) 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:44-49, 2017

关键词： multiple-input multiple-output dielectric resonator antenna high isolation envelope correlation modes

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Active vibration control development in ultra-precision machining

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JOURNAL OF VIBRATION AND CONTROL 2021年第7-8期27卷 790-801页

作者： Aggogeri, Francesco Merlo, Angelo Pellegrini, Nicola Univ Brescia Dept Mech & Ind Engn Via Branze 38 I-25123 Brescia Italy Ce SI Ctr Studi Ind Via Tintoretto Cologno Monzese Italy

This study presents a combined feedback-feedforward adaptive regulator applied to an active vibration control tool holder platform to contain the effect of machining vibrations. The proposed mechatronic solution can be integrated in a milling machine tool as an interface between the beam (Z-axis) and the tool holder. The aim is to counteract vibrations in the broadband frequency range (100 Hz-900 Hz), controlling the tool position in real time. The active vibration control system is based on the harmonic steady-state concept due to the sinusoidal representation of the disturbance signals. The study focuses on the regulator architecture and the main logics applied to satisfy the required performance. A full investigation is executed through simulations and experimental campaigns, proving the disturbance reduction. The active vibration control system is implemented on a 4-axis machine tool and validated using multitonal disturbances. The system is evaluated in compensating a set of undesired effects, such as vibrations generated by unbalanced tools or hard material cutting processes. The obtained results show a maximum reduction of the vibration amplitude by 43.7% at the critical frequency.

关键词： Vibration adaptive control harmonic steady state multiple-input multiple-output

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Generalized Signal Alignment: On the Achievable DoF for Multi-User MIMO Two-Way Relay Channels

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IEEE TRANSACTIONS ON INFORMATION THEORY 2015年第6期61卷 3365-3386页

作者： Liu, Kangqi Tao, Meixia Shanghai Jiao Tong Univ Dept Elect Engn Shanghai 200240 Peoples R China

This paper studies the achievable degrees of freedom (DoF) for multi-user multiple-input multiple-output (MIMO) two-way relay channels, where there are K source nodes, each equipped with M antennas, one relay node, equipped with N antennas, and each source node exchanges independent messages with an arbitrary set of other source nodes via the relay. By allowing an arbitrary information exchange pattern, the considered channel model is a unified one. It includes several existing channel models as special cases: 1) K -user MIMO Y channel;2) multi-pair MIMO two-way relay channel;3) generalized MIMO two-way X relay channel;and 4) L-cluster MIMO multiway relay channel. Previous studies mainly considered the achievability of the DoF cut-set bound 2N at the antenna configuration N < 2M by applying signal alignment for network coding. This paper aims to investigate the achievability of the DoF cut-set bound KM for the case N >= 2M. To this end, we first derive tighter DoF upper bounds for three special cases of the considered channel model. Then, we propose a new transmission framework, generalized signal alignment (GSA), to approach these bounds. The notion of GSA is to form network-coded symbols by aligning every pair of signals to be exchanged in a compressed subspace at the relay. A necessary and sufficient condition to construct the relay compression matrix is given. We show that using GSA, the new DoF upper bound is achievable when: 1) N/M is an element of (0, 2+ 4/K (K4-1) boolean OR [K 2, +oo) for the K -user MIMO Y channel;4 2) m is an element of (0,2 K 1 U [K 2, +oo) for the multi-pair MIMO two-way relay channel;and 3) N/M is an element of (0, 2+ 8/K-2 boolean OR [K 2, +infinity) for the generalized MIMO two-way X relay channel. We also provide the antenna configuration regions for the general multi-user MIMO two-way relay channel to achieve the total DoF KM.

关键词： multiple-input multiple-output two-way relay channel signal alignment degrees of freedom

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