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An effective approach for low-complexity maximum likelihood based automatic modulation classification of STBC-MIMO systems

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Frontiers of Information Technology & Electronic Engineering 2020年第3期21卷 465-476页

作者： Maqsood H.SHAH Xiao-yu DANG College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China

A low-complexity likelihood methodology is proposed for automatic modulation classification of orthogonal space-time block code(STBC)based multiple-input multiple-output(MIMO)*** exploit the zero-forcing equalization technique to modify the typical average likelihood ratio test(ALRT)*** proposed ALRT function has a low computational complexity compared to existing ALRT functions for MIMO systems *** proposed approach is analyzed for blind channel scenarios when the receiver has imperfect channel state information(CSI).Performance analysis is carried out for scenarios with different numbers of ***-STBC systems with 2×2 and 2×1 and space-time transmit diversity with a 4×4 transmit and receive antenna configuration are considered to verify the proposed *** popular modulation schemes are used as the modulation test ***-Carlo simulations are performed to evaluate the proposed methodology,using the probability of correct classification as the *** results show that the proposed approach has high classification accuracy at low signal-to-noise ratios and exhibits robust behavior against high CSI estimation error variance.

关键词： multiple-input multiple-output Space-time block code Maximum likelihood Automatic modulation classification Zero-forcing

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Limited feedback MIMO techniques for temporally correlated channels and linear receivers

Limited feedback MIMO techniques for temporally correlated c...

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作者： Zacarías Brach, Eduardo Aalto University

学位级别：master

Advanced mobile wireless networks will make extensive use of multiantenna (MIMO) transceivers to comply with high requirements of data rates and reliability. The use of feedback channels is of paramount importance to achieve this goal in systems employing frequency division duplexing (FDD). The design of the feedback mechanism is challenging due to the severe constraints imposed by computational complexity and feedback bandwidth *** thesis addresses the design of transmission strategies in both single-user and multi-user MIMO systems, based on compact feedback messages. First, recursive feedback mechanisms for single-user transmission scenarios are proposed, including stochastic gradient techniques, deterministic updates based on Givens rotations and low computational complexity schemes based on partial update filtering concepts. Thereafter, channel feedback algorithms are proposed, and a convergence analysis for static channels is presented. These algorithms can be used to provide channel side information to any multi-user MIMO solution. A limited-feedback decentralized multi-user MIMO solution is proposed, which avoids the need for explicit channel feedback. A feed-forward technique is proposed, which allows our methods to operate in presence of feedback *** performance of all the proposed algorithms is illustrated via link-level simulations, where the effect of different parameter values is assessed. Our results show that the proposed methods outperform existing limited-feedback counterparts over a range of low to medium mobile speeds, for moderate antenna array sizes that are deemed practical for commercial deployment. The computational complexity reduction of some of the proposed algorithms is also shown to be considerable, when compared to existing techniques

关键词： Electrical engineering multiantenna systems multiple-input multiple-output limited feedback wireless communications

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Performance of wireless networks in highly reflective rooms with variable absorption

Performance of wireless networks in highly reflective rooms ...

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作者： Intini, Anibal L. Naval Postgraduate School

学位级别：硕士

Wireless communications provide opportunities to extend the reach of command and control assets to military members separated from traditional wired networks. Indoor wireless systems are already used in a variety of applications, including office, residential, and even military environments. However, highly radio frequency (RF)-reflective rooms, such as internal shipboard compartments, well decks, and amphibious combat vehicles, represent extreme conditions for the use of these systems. While wireless communications under such extreme conditions are very difficult or even impossible due to reflected waves, changes in the environment, such as objects or human bodies moving in and out of the room, produce signal power absorption randomly. The purpose of this thesis is to find an optimized solution for the use of wireless local-area-network devices to provide acceptable throughput in the presence of reflected RF-energy and variable power absorption within reflective compartments. This thesis analyzes the performance of the standard IEEE 802.11ac in reflective environments by testing new available commercial wireless devices in order to provide online access to information and applications from such rooms.

关键词： Wireless Networks Wireless Local Area Networks WLAN WiFi Radiowave Propagation IEEE802.11ac Orthogonal Frequency Division multiplexing OFDM multiple-input multiple-output MIMO Savant Simulation. Major rules will grow employment

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面向三频WiFi应用的分集玻璃天线

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Engineering 2023年第4期23卷 157-169,M0007页

作者：胡鹏飞梁国华陆贵文潘咏梅郑少勇 State Key Laboratory of Terahertz and Millimeter Waves and Department of Electrical Engineering City University of Hong KongHong Kong 999077China School of Electronics and Information Technology(School of Microelectronics) Sun Yat-sen UniversityGuangzhou 510006China Guangdong Provincial Key Laboratory of Optoelectronic Information Processing Chips and Systems Sun Yat-sen UniversityGuangzhou 510006China Information and Communication Technology Center CityU Shenzhen Research InstituteShenzhen 518057China School of Electronic and Information Engineering South China University of TechnologyGuangzhou 510630China

本文研究了两种新型极化和模式分集玻璃介质谐振器天线(DRAs),用于三频段(2.4 GHz、5.2 GHz和5.8 GHz)无线保真(WiFi)应用。研究比较了这两种DRAs以及一种新型空间分集玻璃DRA,以确定哪种分集天线最适合WiFi路由器应用。同时,将这三种... 详细信息

本文研究了两种新型极化和模式分集玻璃介质谐振器天线(DRAs),用于三频段(2.4 GHz、5.2 GHz和5.8 GHz)无线保真(WiFi)应用。研究比较了这两种DRAs以及一种新型空间分集玻璃DRA,以确定哪种分集天线最适合WiFi路由器应用。同时,将这三种分集玻璃DRAs与一个商业空间分集单极对进行比较,以评估玻璃DRA在WiFi路由器应用中的性能。在极化分集天线中,采用双端口馈电方案来激发不同的DRA模式,并通过使用阶梯形DRA来调节DRA模式的频率。对于模式分集设计,引入堆叠式DRA来扩展圆锥和正侧向辐射模的带宽。所有三种新型分集天线均得到了实验验证。在实验中,还测量了三种玻璃分集天线和参考空间分集单极子天线的误码率(BER),并对结果进行了比较和讨论。实验结果表明,在三种天线中,极化分集全向DRA具有最稳定的BER。

关键词： Wireless fidelity Diversity antennas Multi-frequency Glass Dielectric resonator antennas multiple-input multiple-output

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Joint radio frequency front-end and digital back-end antijamming scheme based on a metasurface antenna array

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Frontiers of Information Technology & Electronic Engineering 2023年第12期24卷 1739-1751页

作者： Yangming LOU Liang JIN Wenyu JIANG Shuaifang XIAO PLA Strategic Support Force Information Engineering University Zhengzhou450000China

An array’s degree of freedom(DoF)determines the number of jamming incidents that can be managed and the antijamming *** arrays can improve the DoF only by increasing the number of *** the other hand,when the received signal is digitized,high-power jamming will reduce the number of bits used to represent the desired signal,further increasing the difficulty of back-end antijamming based on digital signal *** this paper,we propose a joint radio frequency(RF)front-end and digital back-end antijamming scheme based on a metasurface antenna *** metasurface antennas can rapidly switch patterns when receiving signals,so that a single channel can be equivalent to multiple channels and increase the *** use independent component analysis to estimate the channel and then optimize the array parameters under the minimum signal-to-jamming ratio constraint of each *** proposed scheme works well under high-power jamming conditions by suppressing jamming at the RF front end and using a low-precision analog-to-digital *** results show that the proposed scheme reduces the bit error rate of the received signals by one order of magnitude compared with the conventional array.

关键词： Antijamming multiple-input multiple-output Metasurface antenna array Independent component analysis

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Performance Analysis of Orthogonal Space-time Block Codes Over Nakagami-? (Hoyt) MIMO RFID Backscattering Channels

Performance Analysis of Orthogonal Space-time Block Codes Ov...

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作者： Yasmin Hisham Tawfiq Qabbani Al-Quds University

学位级别：硕士

Radio frequency identification (RFID) is an automatic identification technology which utilizes radio-frequency electromagnetic fields to identify objects carrying tags in the reading range of a reader. Such identification over a wireless channel doesn't necessitate the tag and the reader being in physical contact or line-of-sight (LOS) aligned. This preferable feature of sending identification data wirelessly may adversely affect the performance of the RFID system, because even when LOS path exists, heavy small-scale fading may still be present due to indoor operation, a cluttered reader environment, and the inhomogeneous nature of the tagged object. To mitigate this fading problem and increase the read reliability, space-time block coding (STBC) for multiple-input multiple-output (MIMO) RFID systems is suggested and employed. In this thesis, a performance analysis of orthogonal space-time block codes (OSTBC) in passive MIMO RFID system is conducted. More particularly, the conditional moment-generating function (MGF) approach is employed to analyse the performance of OSTBC over Nakagami- (Hoyt) MIMO RFID backscattering channels. New exact and asymptotic closed-form symbol error rate (SER) expressions are derived for the case of two and four reader-receiving antennas. The diversity order that the system can achieve is found to be, where is the number of tag antennas, and the performance of this channel is found to be more sensitive to the channel condition (the parameter) of the forward link than that of the backscattering link. A good agreement with previous published studies was observed for the special case that the Hoyt fading covers.

关键词： backscattering cascaded structure Nakagami-(Hoyt) fading radiofrequency identification multiple-input multiple-output symbol error rate diversity gain space-time block code

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DESIGN AND ANALYSIS OF A NOVEL ARCHITECTURE FOR 5G COMMUNICATIONS USING MOBILE RELAYS IN LTE AND MMWAVE BANDS FOR HIGH SPEED TRAINS

DESIGN AND ANALYSIS OF A NOVEL ARCHITECTURE FOR 5G COMMUNICA...

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作者： JOSE DAVID OLIVA SANCHEZ Universidad Politecnica de Madrid

学位级别：硕士

The great advancements in modern communications have permitted to connect people like never before. Nowadays, people are permanently connected. This tendency of ubiquitous connectivity has led users to demand new ways of access and faster and more efficient communication systems. Furthermore, vehicular communications currently lack of good data access for onboard passengers. Concretely in High Speed Trains, railway authorities wish to provide broadband communications to passengers. The aim of this Master Thesis is to study the performance of a novel architecture in High Speed Railways utilizing cutting-edge technologies. In railway scenarios, two types of communications can be considered: critical and non- critical. Critical communications are for signaling and control purposes, hence they handle traffic to provide a minimum Quality of Service (QoS). Critical communications have to ensure passenger safety and provide real-time multimedia information. Various standards have been proposed: GSM-Railway, TETRA or the next-generation network, LTE-R. On the contrary, non- critical communications are specific for information and entertainment for the train passengers. Currently, there are no dedicated standards for the latter type of service. Therefore, railway operators have to come up with their own solutions to provide Wi-Fi to most passengers. High Speed Railway (HSR) scenarios suffer from poor propagation conditions with high fast- fading, high Doppler spread or high Vehicular Penetration Losses (VPL) between others. New architectures and technologies, like the Mobile Relay Node (MRN) or the utilization of millimeter wave (mmWave) bands, have been developed to counteract these adverse effects. Moreover, MIMO techniques permit to increase the link capacity by the number of spatial channels. Ultimately, the combination of all of these technologies will provide the capacity and latency needed for future communications in HSR scenarios. Standardization organizations, like

关键词： 5G Amplify-and-Forward Decode-and-Forward High Speed Train Link-Level Simulator Long Term Evolution Advanced Millimeter Wave Mobile Relay Node multiple-input multiple-output

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Receive Antenna Selection without CSI for Linear Detection

Receive Antenna Selection without CSI for Linear Detection

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4th International Conference on Wireless Communications, Networking and Mobile Computing

作者： Ming-Xue, Chen Nanjing Univ Posts & Telecommun Coll Commun & Informat Nanjing Peoples R China

ISBN: (纸本)9781424421077

multiple-input multiple-output (MIMO) receive antenna selection without channel state information (CSI) for linear detection is proposed in the presence of unknown interferences. This antenna selection technique is implemented based on training sample sequence by minimizing the Least Squares (LS) estimation error, which avoids the channel estimation. Since the high complexity of the exhaustive search, a QR decomposition-based fast selection algorithm is presented by using greedy algorithm. Simulations show that the exhaustive selection can retain the diversity benefit of the full complexity system using all the receive antennas and that the fast selection algorithm obtains most of performance of the exhaustive selection system with linear complexity.

关键词： Antenna Selection multiple-input multiple-output Least Squares QR decomposition

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Multi-stream signals separation based on space-time-isomeric (SPATIO) array using metasurface antennas

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Science China(Information Sciences) 2024年第2期67卷 181-200页

作者： Yangming LOU Liang JIN Huiming WANG Zhou ZHONG Junyan DAI PLA Strategic Support Force Information Engineering University School of Information and Communications Engineering Xi'an Jiaotong University State Key Laboratory of Millimeter Waves Southeast University

In spatial domain signal processing, it is necessary to equip more antennas at the receiver to improve spatial demultiplexing capability. However, increasing the number of antennas under restricted space will reduce antenna spacing and raise the channel correlation, making the number of signal streams spatially demultiplexed much smaller than that of antennas. This paper proposes a method to design a space-timeisomeric(SPATIO) array based on metasurface antennas under wireless multipath conditions. Each antenna in this array has a different pattern and varies independently with time, reducing the channel correlation by superposing multipath at distinct positions and moments. Based on the SPATIO array, we present an array parameter design scheme based on infinity norm minimization, which can maximize the received energy of each stream while separating multi-stream received signals. Simulation results illustrate the performance of the SPATIO array for multi-stream signal reception. Compared with conventional multiple-input multipleoutput arrays, the proposed array can reduce the bit error rate by one order of magnitude under the same simulation conditions.

关键词： multiple-input multiple-output metasurface antenna space-time-isomeric array multipath channel degree of freedom

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Channel estimation and data detection for MIMO systems under spatially and temporally colored interference

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EURASIP JOURNAL ON APPLIED SIGNAL PROCESSING 2004年第5期2004卷 685-695页

作者： Song, Y Blostein, SD Queens Univ Dept Elect & Comp Engn Kingston ON K7L 3N6 Canada

The impact of interference on multiple-input multiple-output (MIMO) systems has recently attracted interest. Most studies of channel estimation and data detection for MIMO systems consider spatially and temporally white interference at the receiver. In this paper, we address channel estimation, interference correlation estimation, and data detection for MIMO systems under both spatially and temporally colored interference. We examine the case of one dominant interferer in which the data rate of the desired user could be the same as or a multiple of that of the interferer. Assuming known temporal interference correlation as a benchmark, we derive maximum likelihood (ML) estimates of the channel matrix and spatial interference correlation matrix, and apply these estimates to a generalized version of the Bell Labs Layered Space-Time (BLAST) ordered data detection algorithm. We then investigate the performance loss by not exploiting interference correlation. For a (5,5) MIMO system undergoing independent Rayleigh fading, we observe that exploiting both spatial and temporal interference correlation in channel estimation and data detection results in potential gains of 1.5 dB and 4 dB for an interferer operating at the same data rate and at half the data rate, respectively. Ignoring temporal correlation, it is found that spatial correlation accounts for about I dB of this gain.

关键词： multiple-input multiple-output interference channel estimation data detection

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