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Very-low-complexity maximum-likelihood decoders for four-transmit-antenna quasi-orthogonal space-time code

IEICE TRANSACTIONS ON COMMUNICATIONS 2005年第9期E88B卷 3802-3805页

作者： Le, MT Pham, VS Mai, L Yoon, G Informat & Commun Univ CEL Lab Taejon 305714 South Korea

This letter proposes two very-low-complexity maximum-likelihood (ML) detection algorithms based on QR decomposition for the quasi-orthogonal space-time code (QSTBC) with four transmit antennas [3]-[5], called VLCMLDec1 and VLCMLDec2 decoders. The first decoder, VLCMLDec1, can be used to detect transmitted symbols being extracted from finite-size constellations such as phase-shift keying (PSK) or quadrature amplitude modulation (QAM). The second decoder, VLCMLDec2, is an enhanced version of the VLCMLDec1, developed mainly for QAM constellations. Simulation results show that both of the proposed decoders enable the QSTBC to achieve ML performance with significant reduction in computational load.

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

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Rate Splitting for Multi-Group Multicasting With a Common Message

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2020年第10期69卷 12281-12285页

作者： Yalcin, Ahmet Zahid Yuksel, Melda Clerckx, Bruno TOBB Univ Econ & Technol TR-06560 Ankara Turkey Imperial Coll London London SW7 2AZ England

In this letter, precoding for max-min fairness (MMF) for multi-group multicasting with a common message is studied. The MMF problem is converted into a weighted mean square error minimization problem. A rate-splitting solution is proposed. In rate-splitting, multicast messages for each group are divided into private and common parts, and these common parts, together with the original common message are combined as a super common message. This super common message is superposed on or concatenated to the private multicast data vector, or it is transmitted via a mixed scheme. Simulations show that RS demonstrates significant gains especially in overloaded systems.

关键词： Common message max-min fairness multi-group multicasting multiple-input multiple-output precoding design rate-splitting

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Early Eviction Technique for Low-Complexity Soft-output MIMO Symbol Detection Based on Dijkstra's Algorithm

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2013年第11期E96A卷 2302-2305页

作者： Kim, Tae-Hwan Korea Aerosp Univ Sch Elect Telecommun & Comp Engn Goyang Si 412791 Gyungui Do South Korea

This letter presents a technique to reduce the complexity of the soft-output multiple-input multiple-output symbol detection based on Dijkstra's algorithm. By observing that the greedy behavior of Dijkstra's algorithm can entail unnecessary tree-visits for the symbol detection, this letter proposes a technique to evict non-promising candidates early from the search space. The early eviction technique utilizes layer information to determine if a candidate is promising, which is simple but effective. When the SNR is 30 dB for 6 x 6 64-QAM systems, the average number of tree-visits in the proposed method is reduced by 72.1% in comparison to that in the conventional Dijkstra's algorithm-based symbol detection without the early eviction.

关键词： multiple-input multiple-output soft output sphere decoding maximum-likelihood detection tree search

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Capacity of MIMO-OFDM systems in spatially correlated indoor fading channels

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IET COMMUNICATIONS 2007年第3期1卷 514-519页

作者： Kafle, P. L. Sesay, A. B. McRory, J. Telecommun Res Lab Calgary AB T2L 2K7 Canada

multiple-input multiple-output (MIMO) wireless systems provide significantly higher capacity compared to the conventional single antenna systems in rich scattering environments. However, the real capacity advantage in a specific channel environment strongly depends on its propagation characteristics. We analyse the capacity of orthogonal frequency division multiplexing-based spatial multiplexing system for indoor fading channels. We model the channel between the transmitter and receiver arrays by considering two indoor propagation models, the extended Saleh-Valenzuela (ESV) model and the geometrically based single bounce elliptical model (GBSBEM). Spatial correlation matrices for the realisations of the ESV and GBSBEM are obtained for the wideband MIMO fading channels, which are then used for the evaluation of mutual information and outage capacity using Monte-Carlo simulations. The behaviour of capacity against outage is investigated for different physical parameters and array geometries. Capacity results are discussed with similar power delay profiles, antenna spacing and angular spreads for uniform linear and circular arrays.

关键词： fading channels spatially correlated indoor fading channels MIMO communication MIMO-OFDM systems GBSBEM models geometrically based single bounce elliptical model indoor radio Monte-Carlo simulations propagation characteristics spatial correlation matrices capacity channel capacity multiple-input multiple-output orthogonal frequency division multiplexing-based spatial multiplexing system mutual information ESV model OFDM modulation indoor propagation wideband channels extended Saleh-Valenzuela model

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Super-UWB MIMO antenna with high isolation

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2022年第11期64卷 2095-2102页

作者： Rahim, Sajjad Yang, Xue-Xia Elobied, Abubaker A. Xiao, Bo-Zhong Shanghai Univ Sch Commun & Informat Engn Dept Commun Engn Shanghai Peoples R China

A 1 x 2 multiple-input multiple-output (MIMO) antenna with super-ultra wideband (super-UWB) operation and high isolation is proposed. The antenna element has an eye-shape radiator fed by a tapered shape feedline on the top side and a defected ground structure etched on the bottom ground plane. A high isolation between two radiators is achieved by introducing a T-shape and two small arm shape stubs at the center of the ground plane. The proposed design was verified by a fabricated prototype and measurement. The measured results show that the MIMO antenna achieves impedance bandwidth of 3 similar to 45 GHz, isolation of 21 dB, and a peak gain of 10.1 dBi. The envelope correlation coefficient is less than 0.02. The overall size of the design is only 0.26 lambda 0L x 0.3 lambda 0L (lambda 0L is the free space wavelength at 3 GHz).

关键词： defected ground structure high isolation multiple-input multiple-output super-UWB ultra-wideband

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On Capacity Scaling of Multi-Antenna Multi-Hop Networks: The Significance of the Relaying Strategy in the "Long Network Limit"

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IEEE TRANSACTIONS ON INFORMATION THEORY 2012年第4期58卷 2107-2133页

作者： Wagner, Joerg Wittneben, Armin ETH Commun Technol Lab CH-8092 Zurich Switzerland

The sum-capacity C of a static uplink channel with n single-antenna sources and an n-antenna destination is known to scale linearly in n, if the random channel matrix fulfills the conditions for the Marcenko-Pastur law: if each source transmits at power P/n, there exists a positive c(0), such that n --> infinity C/n = c(0) almost surely. This paper addresses the question to which extent this result carries over to multi-hop networks. Specifically, an L + 1-hop network with n non-cooperative source antennas, n fully cooperative destination antennas, and L relay stages of n(R) (cooperative or non-cooperative) relay antennas each is considered. Four relaying strategies are assessed based on the interrelationship between two sequences. For each considered strategy XF, there exists a sequence (C-L(XF))(L=0)(infinity), such that C-L(XF) = lim(n) --> infinity R-L(XF) /n almost surely, where R-L(XF) denotes the supremum of the set of sum-rates that are achievable by the strategy over L+1 hops. This sequence depends on the sequence (P-L)(L=0)(infinity), where p(L) corresponds to the power of the source stage and each of the relay stages in an L+1-hop network. Results are summarized as follows: Decode & forward (DF): For n(R) = n, C-L(DF) is constant with respect to L, if also P-L is constant with respect to L. Quantize & forward with (CF) and without (QF) Slepian& Wolf compression: For n(R) = n, there exists a sequence (P-L)(L=0)(infinity), such that C-L(QF/CF) is positive and constant with respect to L. The corresponding sequence (P-L)(L=0)(infinity) grows linearly with L for CF and exponentially with L for QF. Amplify & forward (AF): Fix nR/n = beta and P-L proportional to L. Then, ( i) there exists c > 0, such that lim(L) --> infinity C-L(AF) = c, if beta is an element of Omega (L1+epsilon), and (ii) lim(L) --> infinity C-L(AF) = 0, if beta is an element of O (L1-epsilon).

关键词： Amplify & forward capacity scaling compress & forward decode & forward MIMO uplink multi-hop multiple-input multiple-output quantize& forward random matrix theory Slepian and Wolf compression

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Performance Analysis of STBC-Based MIMO PLC System in Cyclostationary Noise Environment

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2022年第8期71卷 9026-9031页

作者： Dash, Soumya P. Bhuyan, Jashaswini Mallik, Ranjan K. Indian Inst Technol Bhubaneswar Sch Elect Sci Argul Khordha 752050 Odisha India Indian Inst Sci Dept Elect Commun Engn Bengaluru 560012 India Indian Inst Technol Delhi Dept Elect Engn New Delhi 110016 India

The paper proposes a multiple-input multiple-output-based power line communication (PLC) system subject to Rayleigh fading and corrupted by additive cyclostationary Gaussian noise. The proposed coherent receiver structure employs a block reception rule at the reception unit for detecting the space-time block-coded transmitted data symbols. A closed-form expression for the pairwise error probability (PEP) is derived using a characteristic function approach. Exact and asymptotic expressions for the average PEP are obtained for the special case of Alamouti code transmission which show that the PLC system under consideration offers full diversity. Numerical results depict the improvement in the system performance with increase in the number of receive diversity branches and the average signal-to-noise ratio per branch and decrease in the correlation value between the noise samples.

关键词： Receivers Symbols Indexes Codes MIMO communication Data communication Reliability Coherent detection cyclostationary noise multiple-input multiple-output pairwise error probability (PEP) powerline communication space-time block coding

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STAR-RIS Aided Secure MIMO Communication Systems

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2024年第10期73卷 15715-15720页

作者： Dong, Xiequn Fei, Zesong Wang, Xinyi Hua, Meng Wu, Qingqing Beijing Inst Technol Sch Informat & Elect Beijing 100081 Peoples R China Imperial Coll London Dept Elect & Elect Engn London SW7 2AZ England Shanghai Jiao Tong Univ Dept Elect Engn Shanghai 200240 Peoples R China

This paper investigates simultaneous transmission and reflection reconfigurable intelligent surface (STAR-RIS) aided physical layer security (PLS) in multiple-input multiple-output (MIMO) systems, where the base station (BS) transmits secrecy information with the aid of STAR-RIS against multiple eavesdroppers equipped with multiple antennas. We aim to maximize the secrecy rate by jointly optimizing the active beamforming at the BS and passive beamforming at the STAR-RIS, subject to the hardware constraint for STAR-RIS. To handle the coupling variables, a minimum mean-square error (MMSE) based alternating optimization (AO) algorithm is applied. In particular, the amplitudes and phases of STAR-RIS are divided into two blocks to simplify the algorithm design. Besides, by applying the Majorization-Minimization (MM) method, we derive a closed-form expression of the STAR-RIS's phase shifts. Numerical results show that the proposed scheme significantly outperforms various benchmark schemes, especially as the number of STAR-RIS elements increases.

关键词： Array signal processing MIMO communication Optimization Wireless communication Security Eavesdropping Transforms Simultaneous transmission and reflection reconfigurable intelligent surface secure communication multiple-input multiple-output majorization-minimization

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Non-Coherent MIMO of Per Transmit Antenna Differential Mapping (PADM) Employing Asymmetric Space-Time Mapping and Channel Prediction

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IEICE TRANSACTIONS ON COMMUNICATIONS 2017年第5期E100B卷 808-817页

作者： Kubo, Hiroshi Yamagishi, Takuma Mori, Toshiki Ritsumeikan Univ Fac Sci & Engn Kusatsu 5258577 Japan

This paper proposes performance improvement schemes for non-coherent multiple-input multiple-output (MIMO) communication systems employing per transmit antenna differential mapping (PADM). PADM is one form of differential space-time coding (DSTC), which generates an independent differentially encoded sequence for each of the multiple transmit antennas by means of space-time coding and mapping. The features of the proposed schemes are as follows: 1) it employs an asymmetric space-time mapping instead of the conventional symmetric space-time mapping in order to lower the required signal to noise power ratio (SNR) for maintaining the bit error rate (BER) performance;2) it employs an analytically derived branch metric criterion based on channel prediction for per-survivor processing (PSP) in order to track fast time-varying channels. Finally, computer simulation results confirm that the proposed schemes improve the required SNR by around 1 dB and can track at the maximum Doppler frequency normalized by symbol rate of 5%.

关键词： multiple-input multiple-output transmit diversity spatial multiplexing differential space-time signal processing maximum-likelihood detection Viterbi detection

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Optimizing Plasma Etching: Integrating Precise Three-Dimensional Etching Simulation and Machine Learning for Multi-Objective Optimization

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IEEE ACCESS 2024年 12卷 127065-127073页

作者： Guo, Jianming Geng, Mingqiang Ren, Kun Ni, Dong Gao, Dawei Zhejiang Univ Coll Integrated Circuits Hangzhou 311200 Peoples R China Zhejiang ICsprout Semicond Co Ltd Hangzhou 311200 Peoples R China Zhejiang Technol Innovat Ctr CMOS IC Mfg Proc & De Hangzhou 311200 Peoples R China ZJU Hangzhou Global Sci & Technol Innovat Ctr Hangzhou 311215 Peoples R China

In modern semiconductor manufacturing, optimizing plasma etching processes is key for advancing technology and achieving profitable production. In this study, we propose an efficient process flow to calibrate the etching mechanisms and optimize the etch profile by combining three-dimensional plasma simulations with machine learning (ML). Our proposed workflow speeds up the model calibration process and effectively addresses data scarcity issues by integrating extensive simulation data with TEM and other data sources. We have developed a three-dimensional Cl2/HBr/O2 plasma etching model for shallow trench isolation (STI), which is based on physical and chemical reaction mechanisms and external parameters consistent with actual production requirements, such as gas ratio, time duration, and chamber conditions. Machine learning is employed to tackle both forward and inverse problems. In the forward problem, the model predicts etching profiles under varying process conditions, with accuracy and similarity assessed using multiple criteria, including the structural similarity index (SSIM). Our approach achieves a notable reduction in prediction time, completing forecasts in 0.5 seconds compared to the 6500 CPU seconds required by TCAD. In the inverse problem, the model adjusts physical parameters to match observed results, improving its predictive accuracy. After model calibration, predictions are validated with wafer test outcomes, showing relative errors below 7%, thereby confirming the accuracy and robustness of the model parameters and the effectiveness of the entire process.

关键词： Plasma etch Plasma etch 3D etching simulation 3D etching simulation neural networks neural networks shallow trench isolation (STI) shallow trench isolation (STI) machine learning machine learning multiple-input multiple-output multiple-input multiple-output

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