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Improved Channel Estimation for MIMO Interference Cancellation

IEEE COMMUNICATIONS LETTERS 2015年第8期19卷 1355-1357页

作者： Mah, Meng Chuan Lim, Heng Siong Tan, Alan Wee Chiat Multimedia Univ Fac Engn & Technol Bukit Beruang 75450 Melaka Malaysia

In this letter, a jamming resilient communication technique for unmanned aircraft vehicle (UAV) is proposed. multiple-input multiple-output (MIMO) interference cancellation is exploited to combat reactive jamming. An improved channel estimation algorithm based on Kalman filter and basis expansion model (BEM) is used to track the quick changes of the combined channel components. Simulation results show that the performance of the proposed technique is significantly better than the existing jamming resilient communication technique.

关键词： Anti-jamming Kalman filter basis expansion model multiple-input-multiple-output orthogonal frequency-division multiplexing

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Wideband 20-Elements 3D-MIMO Antenna for Localization System

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS 2022年第2期69卷 409-413页

作者： Saurabh, Arun Kumar Meshram, Manoj Kumar Indian Inst Technol BHU Dept Elect Engn Varanasi 221005 Uttar Pradesh India

In this brief, a low-profile wideband quad-element MIMO antenna with high isolation is designed, which is utilized to propose a 20-elements MIMO system. Each element of the MIMO antenna covers a wideband occupying a small area of 15x15 mm(2). The orthogonal symmetric arrangement of a single antenna forms an extremely compact quad-element MIMO antenna having shared ground, and its occupied volume is 0.84 lambda(g)x0.84 lambda(g)x0.019 lambda(g) (lambda(g) at 3.95 GHz) with a minimum (0.155 lambda(g)) edge to edge distance between elements. The proposed antenna has a -10 dB (S-ij is an element of i = j) impedance bandwidth of 77.52% (3.95-8.95 GHz) and a minimum isolation (S-ij is an element of i not equal j) value of 17 dB. The measured and simulated results are found in good agreement that confirms the proposed antenna is appropriate for extending a higher-order MIMO system. Further, a low-profile quad-element MIMO antennas are arranged orthogonally at the four-corners and a quad-element MIMO antenna at the center of form a 20-elements planar MIMO antenna. It can be utilized as a localization system where different user's devices are connected to the primary host.

关键词： Correlation isolation multiple-input-multiple-output mutual coupling wideband

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Three-Dimensional Geometry-Based UAV-MIMO Channel Modeling for A2G Communication Environments

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IEEE COMMUNICATIONS LETTERS 2018年第7期22卷 1438-1441页

作者： Jiang, Hao Zhang, Zaichen Wu, Liang Dang, Jian Southeast Univ Natl Mobile Commun Res Lab Nanjing 210096 Jiangsu Peoples R China

We propose a 3-D elliptic-cylinder unmanned aerial vehicle (UAV) multiple-input-multiple-output (MIMO) channel model for air-to-ground communication environments. The mobility and altitude of UAV transmitters in the elevation plane are studied based on the proposed UAV-MIMO channel model. Furthermore, ground surface and roadside environment reflections are considered to investigate the statistical properties of the proposed UAV-MIMO channel model. Finally, numerical results show that the proposed channel statistics are consistent with previous results for communication channels. Overall, the proposed model, expressed by the space correlation functions, provides a novel and practical approach to investigate UAV-MIMO channels and design vehicular communication systems.

关键词： 3-D channel model unmanned aerial vehicle multiple-input-multiple-output air-to-ground communication environments

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An Eight-Port Circularly Polarized Wideband MIMO Antenna Based on a Metamaterial-Inspired Element for 5G mmWave Applications

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IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS 2023年第7期22卷 1572-1576页

作者： Khan, Asif He, Yejun Chen, Zhi Ning Shenzhen Univ Coll Elect & Informat Engn State Key Lab Radio Frequency Heterogeneous Integr Shenzhen 518060 Peoples R China Natl Univ Singapore Dept Elect & Comp Engn Singapore 119077 Singapore

This letter presents a low-profile, single-layer wideband metamaterial-inspired circularly polarized (CP) multiple-input-multiple-output (MIMO) antenna array. An 8 x 8 antenna array is manufactured on the Rogers RT/Duroid 5880 substrate with a partial ground plane. The dimensions of the proposed MIMO antenna array are 0.285 lambda x 0.11 lambda x 0.001 lambda at 28 GHz, where. is the free-space wavelength. The isolation, gain, and higher axial bandwidth ratio are significantly improved by the introduction of a metamaterial-inspired element. As a result, the proposed circularly polarized MIMO antenna has an impedance bandwidth of 18 GHz, a mutual coupling of no more than -20 dB, an axial ratio bandwidth (ARBW) of 13 GHz, and a peak gain of 20.5 dBi. Significantly, the designated mm Wave band (25-29.5 GHz) for 5G communication is covered by the operating bandwidth of the antenna. MIMO parameters are also discussed in terms of cross-correlation, diversity gain, and mean effective gain to further investigate the performance of the MIMO antenna. Therefore, the suggested antenna array is a good candidate for 5G new radio (NR) smart devices and sensors.

关键词： Circular polarization cross-correlation isolation metamaterial multiple-input-multiple-output

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Constant Weight Polar Coded Orthogonal Space-Time Block Codes for Dimmable Indoor MIMO-VLC Systems

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IEEE COMMUNICATIONS LETTERS 2022年第10期26卷 2395-2399页

作者： Babalola, O. P. Balyan, V Cape Peninsula Univ Technol Dept Elect Elect & Comp Engn ZA-7535 Bellville South Africa

The concatenation of constant weight polar code (CWPC) with orthogonal space-time block code (OSTBC), known as CWPC-OSTBC scheme is proposed for the indoor multiple-input multiple output visible light communication (MIMO-VLC) systems in this letter. The CWPC helps to mitigate against flickering, provides desired dimming targets, and coding gain while the OSTBC achieves MIMO diversity gain. Flicker mitigation and dimming control are obtained based on the modified Knuth balancing method with enhanced prefix coding. This method does not utilise lookup table and thus, it is practicable in the real-time. Numerical results are presented to discuss the channel capacity and bit-error-rate (BER) performance of the proposed CWPC-OSTBC scheme considering different parameters. The results show that increasing the transmission antennas of the OSTBC system provides diversity gains. More so, the CWPC-OSTBC scheme yields an improved coding gain compared to polar code without balancing and other state-of-the-art methods.

关键词： Decoding Encoding Polar codes Codes Light emitting diodes Symbols Reliability Constant weight polar code multiple-input-multiple-output orthogonal space-time block code visible light communication

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All-Optical Distributed MIMO for LiFi: Spatial Diversity Versus Spatial multiplexing

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IEEE ACCESS 2022年 10卷 102646-102658页

作者： Kouhini, Sepideh Mohammadi Hohmann, Julian Mana, Sreelal Mavanchery Hellwig, Peter Schulz, Dominic Paraskevopoulos, Anagnostis Freund, Ronald Jungnickel, Volker Fraunhofer Heinrich Hertz Inst Photon Networks & Syst D-10587 Berlin Germany

LiFi or networked optical wireless communication is likely to play an important role in offloading mobile data traffic from radio into the optical spectrum. As the number of Internet of Things (IoT) devices is growing, the RF spectrum becomes a rare resource. Imaging IoT sensors like cameras, ultrasonic devices, and Lidars have real-time requirements, need a high-capacity uplink, and operate in environments that cause or are sensitive against electromagnetic interference. In this paper, for the first time, we present realtime communication over an all-optical fixed-wireless LiFi link based on the distributed multiple-input multiple-output concept. For distributing the wireless signals, plastic optical fibers are used as an analog front-haul. We study the operation of the distributed multiple-input multiple-output link in two modes, i.e., spatial diversity and spatial multiplexing. For the diversity mode, a new combiner is presented, which can support equal gain as well as selection combining. We demonstrate that selection combining is highly effective and enables a similar LiFi performance in up- and downlink, as it is desirable for industrial applications. For the spatial multiplexing mode, we observe that the channel rank and the achievable throughput depend strongly on the user location. As effective solutions, we study the benefits of angular diversity and multiple-input multiple-output mode switching together with multi-user multiplexing and conclude that a dynamic switching between spatial diversity and spatial multiplexing is a practical approach.

关键词： Light fidelity Optical fibers MIMO communication Optical transmitters Optical fiber communication Diversity reception Optical fiber networks Optical wireless communication plastic optical fiber multi-user multiple-input-multiple-output diversity spatial multiplexing

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Analog I/Q FIR Filter in 55-nm SiGe BiCMOS for 16-QAM Optical Communications at 112 Gb/s

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IEEE JOURNAL OF SOLID-STATE CIRCUITS 2020年第7期55卷 1935-1945页

作者： Verplaetse, Michiel Lambrecht, Joris Vanhoecke, Michael Breyne, Laurens Ramon, Hannes Demeester, Piet Torfs, Guy Univ Ghent IMEC Dept Informat Technol IDLab B-9052 Zwijnaarde Belgium

We propose a novel implementation of a complex analog equalization filter for the compensation of frequency-dependent variations in coherent optical links. The analog compensation filter can be used in coherent-lite optical communication links where digital signal processing (DSP) is removed to limit the complexity and power consumption. In these links, the filter can compensate for electrical bandwidth limitations and distortion introduced by chromatic dispersion in the fiber. The complex filter is implemented by combining four distributed analog finite-impulse response (FIR) filters to obtain the necessary response. The filter delays are implemented using active delay cell structures to create a compact solution. The analog filter is implemented in a 55-nm BiCMOS technology and consumes 185-mW core power for five complex filter taps. Performance is evaluated using the S-parameter measurements, noise and linearity measurements, and real-time system experiments using 112-Gb/s 16-QAM-modulated signals.

关键词： Finite impulse response filters Optical fiber communication Equalizers Dispersion Optical polarization Optical transmitters Delays Analog equalization coherent data center dispersion electronic compensation of dispersion (EDC) multiple-input-multiple-output

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Matrix inversion-less direct decoding for efficient channel estimation in fifth-generation massive MIMO systems

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IET COMMUNICATIONS 2020年第5期14卷 865-871页

作者： Zafar, Mohammad Haseeb Khan, Imran Basheri, Mohammed King Abdulaziz Univ Dept Informat Technol Jeddah Saudi Arabia Univ Engn & Technol Dept Elect Engn Peshawar Pakistan

Massive multiple-input-multiple-output (MIMO) is a fifth-generation wireless technology that equips the cellular base stations (BSs) with a very large number of antenna and is a communication technique of serving several users. Aiming at the problem of the high computational complexity of linear channel estimation and linear decoding in massive MIMO systems, this study proposes two low-complexity decoding algorithms according to the characteristics of the system. The fast decoding algorithm is designed by using the asymptotic orthogonality of the channel in the system to avoid solving the inverse of the channel matrix. In combination with increasing the number of base BS antennas to optimise user channel characteristics, a simple operator decoding algorithm is designed to realise direct decoding without estimating the channel. Simulation results show that the proposed algorithms can effectively reduce the computational complexity while ensuring system performance.

关键词： MIMO communication channel estimation decoding computational complexity matrix inversion-less efficient channel estimation fifth-generation massive MIMO systems multiple-input-multiple-output fifth-generation wireless technology cellular base stations communication technique high computational complexity linear channel estimation low-complexity decoding algorithms fast decoding algorithm channel matrix base BS antennas user channel characteristics simple operator decoding algorithm direct decoding system performance

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Design and Analysis of MIMO Antenna with High Isolation and Dual Notched Band Characteristics for Wireless Applications

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WIRELESS PERSONAL COMMUNICATIONS 2020年第3期112卷 1587-1599页

作者： Sharma, Manish Chitkara Univ Inst Engn & Technol Rajpura Punjab India

A very compact Superwideband multiple-input-multiple-output antenna with dual notched band characteristics is presented. Superwideband characteristics is obtained by means of radiating patch and high isolation between two input ports are obtained by using T-shaped stub in ground plane. Two rejection bands (wireless interoperability for microwave access (WiMAX)/C-band and wireless local area network) are obtained by etching two elliptical slots on radiating patch. Antenna offers large measured useable bandwidth of 2.60-20.04 GHz. Diversity performance is studied in terms of envelope correlation coefficient, diversity gain and total active reflection coefficient. Antenna also offers desirable radiation pattern, gain and radiation efficiency which makes proposed antenna quite suitable for different wireless applications.

关键词： Superwideband multiple-input-multiple-output ECC DG TARC

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Optimization of hybrid high-throughput MIMO system with misaligned FSO link under varied weather

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OPTICAL ENGINEERING 2021年第8期60卷

作者： Dubey, Dheeraj Prajapati, Yogendra Kumar Tripathi, Rajeev Motilal Nehru Natl Inst Technol Dept Elect & Commun Allahabad Uttar Pradesh India

We investigate the adverse impact of pointing errors (PEs) on the efficiency of free-space optical communication under varied weather conditions using hybrid subcarrier intensity modulation over a fading regime. The error rate is improved by implementing topological permutations at the trans-receiver to achieve a bit error rate of 10(-10). The derived combined probability density function expressions are defined as generalized infinite power series for precision, which supersedes Meijer-G. The outcomes are contrasted with BPSK-SIM and pulse position modulation, validating its agreement with favored aspects. The undesirable influence of PEs is balanced by widening the beam-waist at the expense of the received irradiance in a multiple-input-multiple-output, MIMO(2x2) system, until a normalized jitter cut-off of 3.35. Afterward, single-input-multiple-output, SIMO(1x3), emerges to be more reliable, providing the flexibility to select the optimum order concerning the quality of service. (C) 2021 Society of Photo-Optical Instrumentation Engineers (SPIE)

关键词： pointing error free-space optics hybrid-subcarrier intensity modulation multiple-input-multiple-output normalized jitter

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