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Unequal Power Allocation for JPEG Transmission Over MIMO systems

IEEE TRANSACTIONS ON IMAGE PROCESSING 2010年第2期19卷 410-421页

作者： Sabir, Muhammad Farooq Bovik, Alan Conrad Heath, Robert W., Jr. VuCOMP Inc Richardson TX 75080 USA Univ Texas Austin Dept Elect & Comp Engn Lab Image & Video Engn Austin TX 78712 USA Univ Texas Austin Dept Elect & Comp Engn Austin TX 78712 USA

With the introduction of multiple transmit and receive antennas in next generation wireless systems, real-time image and video communication are expected to become quite common, since very high data rates will become available along with improved data reliability. New joint transmission and coding schemes that explore advantages of multiple antenna systems matched with source statistics are expected to be developed. Based on this idea, we present an unequal power allocation scheme for transmission of JPEG compressed images over multiple-input multiple-output systems employing spatial multiplexing. The JPEG-compressed image is divided into different quality layers, and different layers are transmitted simultaneously from different transmit antennas using unequal transmit power, with a constraint on the total transmit power during any symbol period. Results show that our unequal power allocation scheme provides significant image quality improvement as compared to different equal power allocations schemes, with the peak-signal-to-noise-ratio gain as high as 14 dB at low signal-to-noise-ratios.

关键词： Distortion model joint source-channel coding JPEG multiple-input multiple-output systems unequal error protection unequal power allocation

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On the Spectral Efficiency of Orbital Angular Momentum With Mode Offset

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2021年第11期70卷 11748-11760页

作者： Almradi, Ahmed Abbasi, Muhammad Ali Babar Matthaiou, Michail Fusco, Vincent F. BT Labs Ipswich IP5 3RE Suffolk England Queens Univ Inst Elect Commun & Informat Technol ECIT Belfast BT3 9DT Antrim North Ireland

Thanks to its low transceiver complexity, mode division multiplexing (MDM) using orbital angular momentum (OAM) has been recently investigated as a new physical layer wireless transmission technique. This is due to the fact that different OAM modes are spatially orthogonal to each other, thus, perfectly suitable for spatial multiplexing and/or diversity. The orthogonality amongst different OAM modes is achieved in the absence of any mode offset between the transceivers' phase-shifting feeding networks. However, the inherent presence of OAM mode offset destroys the orthogonality between different modes, which gives rise to inter-mode interference (IMI). Therefore, in this paper, in order to theoretically analyze the negative impact of OAM mode offset of MDM-OAM systems on the spectral efficiency of line-of-sight free-spacewireless communication systems, an explicit signal-to-interference-plus-noise ratio expression for each OAM mode is derived, through which the spectral efficiency degradation is evaluated. Furthermore, in order to support our theoretical analysis, a 9 x 9 MDM-OAM practical communication experiment for different OAM mode settings is carried out at a microwave frequency of 5.8 GHz. In addition, by leveraging the fact that all circulant matrices always have the same eigendirections, regardless of the entries of the matrix, a low-complexity optimal OAM mode selection scheme is proposed which significantly improves the spectral efficiency of the system. Finally, in order to completely null-out the impact of OAM mode offset, a baseband zero-forcing stage is embedded at the receiver.

关键词： Mode division multiplexing multiple-input multiple-output systems orbital angular momentum spatial multiplexing uniform circular antenna array zero-forcing

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Generic Approach to the Performance Analysis of Correlated Transmit/Receive Diversity MIMO systems With/Without Co-Channel Interference

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IEEE TRANSACTIONS ON INFORMATION THEORY 2010年第3期56卷 1147-1157页

作者： Yue, Dian-Wu Zhang, Q. T. Dalian Maritime Univ Coll Informat Sci & Technol Dalian 116026 Liaoning Peoples R China City Univ Hong Kong Dept Elect Engn Kowloon Hong Kong Peoples R China

Optimal transmit/receive diversity (TRD) is one of the most important configurations for wireless multiple-input multiple-output (MIMO) systems, due to its good performance and ease of implementation. Though investigated intensively, the performance of optimal TRD in general correlated fading with cochannel interference is still not well understood. Since the optimal TRD's output instantaneous signal-to-interference-plus-noise ratio (SINR) is equal to the largest sample eigenvalue of a quadratic form involving signal and interference channel matrices, directly determining the probability density function (pdf) of this eigenvalue has been a prevailing approach in the literature. Given the nonlinearity involved in the quadratic form, however, finding such a pdf is not simple except for some special channel conditions. In this paper, we formulate the problem, in a totally different framework, as testing the positive-definiteness of a random matrix whereby the theory of matrix-variate distributions can be invoked to obtain exact solutions in terms of special functions. The solutions are very general including most of existing results as a special case and allowing for the correlation structures of both signal and interferers to be arbitrary at both transmitter and receiver ends. Numerical results are presented to validate the theoretical analysis.

关键词： Matrix variate distributions multiple-input multiple-output systems optimal transmit/receive diversity outage performance

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Low-Complexity Decoding in DF MIMO Relaying System

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2013年第3期62卷 1123-1137页

作者： Bansal, Ankur Bhatnagar, Manav R. Hjorungnes, Are Han, Zhu Indian Inst Technol Delhi Dept Elect Engn New Delhi 110016 India Univ Oslo Univ Grad Ctr UNIK NO-2027 Kjeller Norway Univ Houston Dept Elect & Comp Engn Houston TX 77004 USA

We derive a maximum-likelihood (ML) decoder for decode-and-forward (DF) based multiple-input-multiple-output (MIMO) cooperative systems having an equal number of antennas at the source and relay nodes, and utilizing an arbitrary complex-valued M-ary constellation. The DF-based MIMO cooperative system considered in this paper utilizes orthogonal space-time block codes (OSTBCs) for the transmission of data of the source to the destination. To reduce the decoding complexity, a suboptimal piecewise linear (PL) decoder is also derived, which performs close to the ML decoder. The proposed ML and PL decoders are applicable to arbitrary complex-valued M-ary constellations and require the destination node to possess knowledge of the channel statistics of the source-relay (S-R) links, whereas the existing decoder of multi-antenna-based DF cooperative systems needs to know the exact channel coefficients of the S-R link at the destination. The proposed decoders outperform an amplify-and-forward (AF)-protocol-based multi-antenna cooperative system. We obtain an expression of the average probability of error of the proposed PL decoder using an M-phase-shift keying (M-PSK) constellation and a single MIMO relay. The approximate symbol error rate (SER) of the proposed PL decoder is derived with multiple MIMO relays, M-PSK constellation, and asymptotically high signal-to-noise ratio (SNR) of the S-R links. It is analytically shown that the proposed ML and PL decoders achieve maximum possible diversity in the multi-antenna cooperative system with a single relay.

关键词： Decode-and-forward protocol diversity multiple-input multiple-output systems orthogonal space-time block code

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A non-stationary relay-based 3D MIMO channel model with time-variant path gains for human activity recognition in indoor environments

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ANNALS OF TELECOMMUNICATIONS 2021年第11-12期76卷 827-837页

作者： Hicheri, Rym Abdelgawwad, Ahmed Patzold, Mathias Univ Agder Fac Sci & Engn NO-4898 Grimstad Norway

Extensive research showed that the physiological response of human tissue to exposure to low-frequency electromagnetic fields is the induction of an electric current in the body segments. As a result, each segment of the human body behaves as a relay, which retransmits the radio-frequency (RF) signal. To investigate the impact of this phenomenon on the Doppler characteristics of the received RF signal, we introduce a new three-dimensional (3D) non-stationary channel model to describe the propagation phenomenon taking place in an indoor environment. Here, the indoor space is equipped with a multiple-input multiple-output (MIMO) system. A single person is moving in the indoor space and is modelled by a cluster of synchronized moving point scatterers, which behave as relays. We derive the time-variant (TV) channel transfer function (CTF) with TV path gains and TV path delays. The expression of the TV path gains is obtained from the instantaneous total received power at the receiver side. This TV total received power is expressed as the product of the TV power of the RF signal initially transmitted and received by a body segment and the TV received power of the redirected signal. These TV powers are determined according the free-space path-loss model. Also, a closed-form approximate solution to the spectrogram of the TVCTF is derived. Here, we analyse the effect of the motion of the person and the validity of the relay assumption on the spectrogram, the TV mean Doppler shift (MDS), and the TV Doppler shift (DS) of the TVCTF. Simulation results are presented to illustrate the proposed channel model.

关键词： Non-stationary channels Doppler characteristics Time-variant path gains Spectrogram multiple-input multiple-output systems Human activities recognition

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Performance analysis of spatially distributed MIMO systems

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IET COMMUNICATIONS 2017年第4期11卷 566-575页

作者： Bashar, Farhana Abhayapala, Thushara D. Australian Natl Univ Res Sch Engn Canberra ACT 0200 Australia

With the growing popularity of ad-hoc sensor networks, spatially distributed multiple-input multiple-output (MIMO) systems have drawn a lot of attention. This work considers a spatially distributed MIMO system with randomly distributed transmit and receive antennas over spatial regions. The authors use the modal decomposition of wave propagation to analyse the performance limits of such system, since the sampling of the spatial regions populated with antennas is a form of mode excitation. Specifically, they decompose signals into orthogonal spatial modes and apply concepts of MIMO communications to quantify the instantaneous capacity and the outage probability. The authors' analysis shows that analogous to conventional point-to-point MIMO system, the instantaneous capacity of spatially distributed MIMO system over Rayleigh fading channel is equivalent to a Gaussian random variable. Afterwards, they derive an accurate closed-form expression for the outage probability of proposed system utilising the definition of instantaneous capacity. Besides, in rich scattering environment, the spatially distributed MIMO system provides best performance when the spatial regions are of same size, and each region is equipped with equal number of antennas. Furthermore, to facilitate the total transmit power allocation among the channels, they propose an algorithm which indicates a significant performance improvement over conventional equal transmit power allocation scheme, even at low signal-to-noise ratio.

关键词： MIMO communication Rayleigh channels receiving antennas transmitting antennas radiowave propagation signal sampling probability Gaussian processes telecommunication network reliability random processes performance analysis spatially distributed MIMO systems ad-hoc sensor networks multiple-input multiple-output systems receive antennas transmit antennas wave propagation modal decomposition performance limits spatial regions sampling mode excitation signal decomposition orthogonal spatial modes outage probability Rayleigh fading channel Gaussian random variable closed-form expression total transmit power allocation performance improvement signal-to-noise ratio

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Exploiting transformation optics for arbitrary manipulation of antenna radiation pattern

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IET MICROWAVES ANTENNAS & PROPAGATION 2019年第9期13卷 1271-1279页

作者： Barati, Hooman Fakheri, Mohammad Hosein Abdolali, Ali Iran Univ Sci & Technol Sch Elect Engn Appl Electromagnet Lab Tehran *** Iran

Using transformation optics, a general method for tailoring the radiation pattern of a monopole antenna encompassed by a coating layer is proposed. Unlike previous studies, the propounded approach is not restricted to special patterns and can produce arbitrary radiation pattern with customisable beam parameters such as number, direction, and directivity in both azimuthal and elevation planes. A linear coordinate transformation is established to simplify the coating layer realisation via offering homogeneous materials. As proof-of-principle, two different antennas capable of generating multiple beams and a single-directive beam, are elaborately acquired by a meta-structure consisting of a split-ring resonator-wire array composite. It was observed that the experimental results corroborate numerical simulations. The proposed approach is believed to have potential applications in antenna technologies, satellite communication, and multiple-input multiple-output systems.

关键词： MIMO communication monopole antennas antenna radiation patterns metamaterial antennas strip line resonators multiple beams single-directive beam meta-structure consisting split-ring resonator-wire array composite antenna technologies multiple-input multiple-output systems transformation optics antenna radiation pattern monopole antenna arbitrary radiation pattern customisable beam parameters linear coordinate transformation coating layer realisation homogeneous materials azimuthal planes elevation planes

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Field-Programmable System-on-Chip-Based Control System for Real-Time Distortion Correction in Optical Imaging

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IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS 2021年第4期68卷 3370-3379页

作者： Radner, Hannes Stange, Johannes Buttner, Lars Czarske, Jurgen Tech Univ Dresden Fac Elect & Comp Engn Lab Measurement & Sensor Syst Tech D-01062 Dresden Germany

The digital transition requires real-time control of complex systems with short loop time and low latency in various applications. Field-programmable gate arrays (FPGAs) are, in principle, capable of complying with this task but demand, on the other hand, a high programming effort. In this article, we propose a field-programmable system on chip (FPSoC) as a hybrid solution of an FPGA and a central processing unit (CPU) on a single monolithic die to combine the strengths of both architectures. An FPSoC-based adaptive optical wavefront correction system is presented as a case study to correct camera images in real time that are distorted by time-varying aberrations. While a short total loop time is achieved by interfacing the camera and a deformable mirror on a low level directly with the FPGA, all computationally nonintensive tasks are implemented on the CPU to keep the flexibility, reusability, and development expense low. The system corrects the optical distortion of water surface waves with up to 3600 control cycles per second and spatially attenuates the distortion up to Zernike polynomial 14 with up to 150 Hz. The FPSoC system enables fast spatiotemporal aberration correction in technical processes and offers a perspective for measuring complex flows through fluctuating interfaces.

关键词： Optical distortion Optical surface waves Adaptive optics Optical sensors Optical imaging Mirrors Distortion measurement Adaptive optics field-programmable system on chip (FPSoC) multiple-input multiple-output systems wavefront correction

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Data-driven stability margin for linear multivariable systems

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INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL 2024年第13期34卷 8844-8862页

作者： Ren, Jinrui Quan, Quan Xu, Bin Wang, Shuai Cai, Kai-Yuan Xian Univ Posts & Telecommun Sch Automat Xian Peoples R China Beihang Univ Sch Automat Sci & Elect Engn Beijing 100191 Peoples R China Northwestern Polytech Univ Sch Automat Xian Shaanxi Peoples R China

The notion of stability margin (SM) plays an important role in control engineering. For multiple-input multiple-output (MIMO) systems, the classic SM is no longer applicable. The one-loop-at-a-time analysis method may lead to unreliable SMs. Although some robust SM analysis methods are popular in MIMO systems, they are model-based or not easy-to-use in engineering sometimes. In this paper, & Laplacetrf;2$$ {\mathcal{L}}_2 $$ gain margin and & Laplacetrf;2$$ {\mathcal{L}}_2 $$ time-delay margin are defined for linear MIMO systems, and a corresponding SM analysis method is proposed by utilizing a loop transformation and the small-gain theorem. Most importantly, a data-driven method for measuring the defined SMs is also presented. As a frequency-domain method, this method can be used to experimentally obtain the SMs of MIMO systems on model-free occasions. The proposed SM analysis method and measurement method are simple and practical. Two simulation studies and an experimental test are performed to illustrate the effectiveness and practicability of the proposed method.

关键词： autonomous, dependable, and affordable (ADA) control data-driven frequency domain frequency-sweep method gain margin multiple-input multiple-output systems small-gain theorem stability margin time-delay margin

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Distributed Space-Time Trellis Code for Asynchronous Cooperative Communications under Frequency-Selective Channels

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2009年第2期8卷 796-805页

作者： Zhong, Zhimeng Zhu, Shihua Nallanathan, Arumugam Xi An Jiao Tong Univ Dept Informat & Commun Engn Xian 710049 Peoples R China Kings Coll London Div Engn London England

In most cooperative communication works, perfect synchronization among relay nodes is assumed in order to achieve the cooperative diversity. However, this assumption is not realistic due to the distributed nature of each relay node. In this paper, we propose a family of distributed space-time trellis code (DSTTC) that does not require the synchronization assumption. It is shown that the proposed DSTTC has minimum memory order, and the construction of such DSTTCs is equivalent to using the generator matrices that have full row rank, regardless of sub-matrices shifting problem. Here, a sub-matrix corresponds to the generator matrix of a relay node under frequency-selective channels. We derive sufficient conditions on the code design such that the full cooperative and multipath diversities can he achieved. By further studying the diversity product, we design the DSTTCs which can achieve full diversity and the maximum coding gain through the exhaustive computer search. The newly proposed codes exhibit good properties, e.g., high energy efficiency and low synchronization cost, and can be applied to distributed wireless networks. Finally, various numerical examples are provided to corroborate the analytical studies.

关键词： Asynchronous cooperative diversity wireless sensor networks distributed space-time trellis code multiple-input multiple-output systems cooperative communications

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