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Online tracking of coherent signals over multiple-input multiple- output code division multiple access communication channel using JADE-Capon method in conjunction with iterative space-time lifting preprocessing scheme

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IET WIRELESS SENSOR SYSTEMS 2012年第2期2卷 146-159页

作者： Ghnimi, S. Gharsallah, A. Campus Univ Tunis El Manar Fac Sci Tunis Circuits & Syst Elect HF Tunis 2092 Tunisia

The main motivation for this work is how to handle the circumvent problem encountered in decorrelating perfect coherent multipath signals over MIMO-CDMA channel with small number of sensors and few data snapshots. The authors propose a new iterative space-time lifting preprocessing (ISTLP) decorrelating scheme that guarantees a perfect decorrelating of a great number of impinging signals even when they are fully correlated and overlaying in space and time domains. It is based on exploiting iteratively the spatial and temporal redundancies arising from multiple antennas and multiple slots. The temporal lifting scheme is introduced first, for efficient tracking and cancelling of ISI, MAI and noise effects within the bank of the N-tapped-delay-lines associated with the user of interest. Secondly, this iterative multi-resolution approach will be coupled to a preprocessing scheme to allow easy transformation of resulting temporal-lifted covariance matrix from time domain to an equivalent Vandermonde structure in frequency domain to be exploited in spatial lifting step. Two detection criteria are therefore established to attempt the convergence state in ISTLP algorithm. Finally, a JADE-Capon method based on ST-MVDR beamformer is applied to the spatial-temporal-lifted preprocessed covariance matrix to compute the joint azimuth-direction-of-arrival and delay of desired Ki multipath signals. The efficacy and high resolution capability of the proposed estimation approach is supported by numerical simulation results.

关键词： Electromagnetic compatibility and interference code division multiple access communication channel online tracking convergence state multipath channels noise effects Linear algebra (numerical analysis) multiple-input multiple-output iterative space-time lifting preprocessing scheme JADE-Capon method Signal processing and detection intersymbol interference code division multiple access ST-MVDR beamformer multiple access interference multiple access communication joint azimuth-direction-of-arrival perfect coherent multipath signals iterative methods covariance matrices space-time adaptive processing temporal lifted covariance matrix temporal lifting scheme high resolution capability equivalent Vandermonde structure Interpolation and function approximation (numerical analysis) MIMO-CDMA channel coherent signals signal processing Radio links and equipment N-tapped-delay-lines direction-of-arrival estimation MAI MIMO communication interference suppression

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Time Reversal Linearly Constrained Minimum Power Algorithm for Direction of Arrival Estimation in Diffuse Multipath Environments

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REMOTE SENSING 2020年第20期12卷 3344-3344页

作者： Xiong, Chao Fan, Chongyi Huang, Xiaotao Natl Univ Def Technol Coll Elect Sci & Technol Changsha 410003 Peoples R China

Direction of arrival (DOA) estimation in diffuse multipath environments is a challenge for ground-based radar remote sensing applications, which has significant value in military fields, such as air defense surveillance. However, radar received echo usually contains various multipath signals caused by the reflection of complex ground or sea surface. With the introduction of multipath signals, traditional algorithms' performance on angle estimation decreases severely. In response to this problem, the letter proposes a new time reversal (TR) algorithm used for multiple-input multiple-output (MIMO) radar angle estimation. First, the algorithm reconstructs a TR covariance matrix by multiplexing the data's rows and columns, increasing the estimation accuracy of the TR covariance matrix. Besides, the letter applies a linearly constrained minimum power (LCMP) constraint to suppress diffuse multipath signals according to the prior knowledge of environments. Simulation results examine the improvement of estimation accuracy by the proposed algorithm, also verify the superiority of the proposed algorithm in different multipath scenarios. What's more, the algorithm has broader applicability due to avoiding the difficulties of removing the coherence and estimating multipath number in practice.

关键词： diffuse multipath direction of arrival linearly constrained minimum power multiple-input multiple-output time reversal

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Robust Sparse Recovery DOA Estimation for MIMO Radar under Unknown Mutual Coupling

Robust Sparse Recovery DOA Estimation for MIMO Radar under U...

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International Applied-Computational-Electromagnetics-Society Symposium - China (ACES)

作者： Meng, Dandan Wang, Xianpeng Huang, Mengxing Guo, Yuehao Li, Liangliang Hainan Univ State Key Lab Marine Resource Utilizat South Chin Haikou Hainan Peoples R China Hainan Univ Coll Informat & Commun Engn Haikou Hainan Peoples R China

ISBN: (纸本)9780996007894

A novel block sparse reconstruction algorithm is presented for direction-of-arrival (DOA) estimation in the presence of unknown mutual coupling of the monostatic multiple-input multiple-output (MIMO) radar. Consider the banded complex symmetric Toeplitz structure of the unknown mutual coupling matrices (MCM) in both transmit and receive array, a new block representation model is constructed first by parameterizing the steering matrices to avoid the influence of mutual coupling and has no loss of array aperture. Then, a reduced-dimensional transformation matrix is structured to eliminate the redundant rows in the received data for reducing the computational complexity. Finally, the DOA estimation problem can be transformed into minimization constrained optimization problem. The simulation results show that the proposed algorithm outperforms the existing algorithms for DOA estimation under unknown mutual coupling conditions in monostatic MIMO radar.

关键词： DOA estimation multiple-input multiple-output block sparse reconstruction unknown mutual coupling

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One-Bit Precoding Constellation Design via Autoencoder-Based Deep Learning 53

One-Bit Precoding Constellation Design via Autoencoder-Based...

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53rd Asilomar Conference on Signals, Systems, and Computers (ACSSC)

作者： Sohrabi, Foad Yu, Wei Univ Toronto Dept Elect & Comp Engn Toronto ON M5S 3G4 Canada

ISBN: (纸本)9781728143002

This paper considers a multicasting system in which the base station has a large number of antennas with cost-effective one-bit digital-to-analog converters and aims to send a common symbol to multiple remote users. Unlike the existing literature which seeks to design the one-bit precoder for a given constellation, e.g., quadrature amplitude modulation (QAM) or phase shift keying (PSK), this paper aims to jointly design the transmit one-bit precoder and the receive constellation by leveraging the concept of autoencoder, wherein the end-to-end multicasting system is modeled using a deep neural network with the one-bit precoding constraint represented by a binary thresholding layer. To deal with the issue that such a binary layer always produces a gradient of zero, and thus prevents an effective end-to-end training when using the conventional back-propagation method, this paper uses a variant of straight-through estimator which approximates the thresholding function with a properly scaled sigmoid function in the back-propagation phase. Numerical results show that, for a fixed channel scenario, the proposed autoencoder-based constellation design is superior to the conventional QAM and PSK constellations. Using the insights obtained from fixed channel scenarios, we also propose a constellation design for varying channel scenarios and numerically show that the proposed design achieves a better performance as compared to the conventional constellations.

关键词： autoencoder binary neurons deep neural network one-bit precoding multiple-input multiple-output

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Low angle estimation for MIMO radar with arbitrary array structures

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International Journal of Electronics Letters 2019年第4期7卷 422-433页

作者： Wang, Shenghua Cao, Yunhe Su, Hongtao Wang, Yu National Laboratory of Radar Signal Processing Xidian University Xi’an China

Low angle target estimation is always a difficult problem for radar elevation estimation. multiple-input multiple-output (MIMO) radar can increase array degree of freedom and resolution, and improve the low angle target measurement precision. At the same time, the computation complexity of the MIMO radar is also increasing, especially for non-uniform linear array (ULA) configuration in which some fast algorithms cannot be used. In this paper, a fast low angle target estimation method is proposed for monostatic MIMO radar with arbitrary array configurations. With the array interpolation and the quasi-spatial-smoothing technique, the MIMO steering vector can be transformed into a virtual low dimension (typical similar size as the number of array elements) ULA steering vector. Then, the polynomial rooting algorithm is used to estimate the elevation of the low angle target. The simulation results of the proposed algorithm are presented and the performances are investigated and analysed. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.

关键词： array processing multiple-input multiple-output parameter estimation radar processing Signal processing

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Artificial-Noise Aided Precoding Design for MIMO Integrated Radar and Communication Systems 11

Artificial-Noise Aided Precoding Design for MIMO Integrated ...

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11th IEEE International Conference on Wireless Communications and Signal Processing (WCSP)

作者： Zhou, Yifan Zhou, Huilin Zhou, Fuhui Ma, Shuai Hu, Rose Qingyang Nanchang Univ Nanchang Jiangxi Peoples R China Utah State Univ Logan UT 84322 USA Univ Min & Technol Xuzhou Jiangsu Peoples R China

ISBN: (纸本)9781728135557

Integrated radar and communication (IRC) systems are promising in the next generation wireless communication networks. However, to realize high level security of information transmission in IRC systems is challenging due to the large transmission power and the open unguided nature of the wireless channels. In this paper, the secure precoding and artificial noise (AN) techniques are investigated to improve the secrecy rate of a multiple-input multiple-output IRC system with multiple eavesdroppers. The formulated secrecy rate maximization problem is non-convex due to the logarithmic of the determinant that exists in the objective function. Instead of using Taylor series approximation of the non-convex elements, we propose to linearize two log-det terms to tackle this challenging problem. After linearization, an alternating optimization algorithm is proposed to solve the primitive problem. Moreover, a first-order approximation is employed to handle the quadratic constraint on radar detection performance. The suboptimal secure precoding and AN scheme can be obtained for maximizing the information security transmission rate of the legitimate receiver while ensuring the performance of radar detection. Simulation results are presented to validate the performance of our proposed design.

关键词： Integrated radar and communication physical-layer security multiple-input multiple-output artificial noise secrecy rate maximization multiple eavesdroppers

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Statistics-Assisted Beam Training for MmWave Massive MIMO Systems

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IEEE COMMUNICATIONS LETTERS 2019年第8期23卷 1401-1404页

作者： Liu, Wendong Wang, Zhaocheng Tsinghua Univ Beijing Natl Res Ctr Informat Sci & Technol Dept Elect Engn Beijing 100084 Peoples R China Tsinghua Univ Grad Sch Shenzhen Div Informat Sci & Technol Shenzhen 518055 Peoples R China

Combined with massive multiple-input multiple-output technology, beamforming can effectively compensate the high path-loss of millimeter-wave signals and hence improve the received power at user equipment (UE). In order to establish the beam alignment between base station (BS) and UE, beam training (BT) is required to select appropriate beamforming vectors at both BS and UE sides. In general, a good trade-off between beamforming gain and BT overhead is critical to enhance the system performance. In this letter, a statistics-assisted beam training (SA-BT) scheme is proposed to reduce the BT overhead. Specifically, BS scans the candidate beams according to the descending order of the utilization frequency of each beam. Meanwhile, the BT procedure is finished when the beamforming gain at UE exceeds the pre-defined threshold. The theoretical analyses and the numerical simulations prove that the proposed scheme can reduce the BT overhead and hence improve the spectral efficiency significantly compared with the existing methodologies.

关键词： multiple-input multiple-output beam training

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Power Allocation Algorithm of Optical MIMO NOMA Visible Light Communications 9

Power Allocation Algorithm of Optical MIMO NOMA Visible Ligh...

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IEEE 9th International Conference on Electronics Information and Emergency Communication (ICEIEC)

作者： Liu, Xiaoyi Yu, Hongyi Zhu, Yijun Zhang, Erfeng Natl Digital Switching Syst Engn & Technol Res Ct Zhengzhou Henan Peoples R China

ISBN: (纸本)9781728111902

Visible light communication (VLC) is a promising technique in future networks due to its advantages of high data rate and licensed-free spectrum. In this paper, we apply the non-orthogonal multiple access (NOMA) technique to improve the achievable sum rate of multipleinput multiple-output (MIMO)-based multi-user visible light communication (VLC) systems. To ensure efficient and low complexity power allocation in indoor MIMO-NOMA-based VLC systems, a normalized gain difference power allocation (NGDPA) method is first proposed by exploiting users' channel conditions. We investigate the performance of an indoor 2x2 MIMO-NOMA based multi-user VLC system through numerical simulations. The obtained results show that the achievable sum rate of the 2x2 MIMO-VLC system can be significantly improved by employing NOMA with the proposed NGDPA method. It is demonstrated that NOMA with NGDPA achieves a sum rate improvement of up to 29.1% compared with NOMA with the gain ratio power allocation method in the 2 x 2 MIMO-VLC system with three users.

关键词： visible light communication multiple-input multiple-output non-orthogonal multiple access power allocation

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Real-Time Single Channel Over-the-Air Data Acquisition for Digital Predistortion of 5G Massive MIMO Wireless Transmitters

Real-Time Single Channel Over-the-Air Data Acquisition for D...

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6th IEEE MTT-S International Wireless Symposium (IWS) part of China Microwave Week

作者： Wang, Xiaoyu Yu, Chao Li, Yue Hong, Wei Zhu, Anding Univ Coll Dublin RF & Microwave Res Grp Dublin Ireland Southeast Univ State Key Lab Millimeter Wave Nanjing Jiangsu Peoples R China

ISBN: (纸本)9781728107165

In this paper, a single channel over-the-air (OTA) data acquisition approach for real-time calibration of digital predistorter in multiple-input multiple-output transmitters is proposed. By using the data acquired from the far-field OTA tests, the output of each power amplifier (PA) can be virtually reconstructed and thus the linearization reference at the main beam direction can be accurately estimated. Digital predistortion (DPD) can therefore be effectively constructed without direct measurement at PA output. Experimental results demonstrate that the proposed scheme can accurately estimate far-field main beam data and the proposed DPD can achieve excellent linearization performance.

关键词： 5G beam-forming over-the-air digital predistortion multiple-input multiple-output millimeter wave power amplifier

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MIMO Receiver with Reduced Number of RF Chains Based on 4D Array and Software Defined Radio 27

MIMO Receiver with Reduced Number of RF Chains Based on 4D A...

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27th European Signal Processing Conference (EUSIPCO)

作者： Bogdan, Grzegorz Godziszewski, Konrad Yashchyshyn, Yevhen Warsaw Univ Technol Warsaw Poland

ISBN: (纸本)9789082797039

multiple-input multiple-output (MIMO) technique is expected to be extensively used in future wireless systems to increase capacity of wireless channels. Nevertheless, the capacity gain comes with a cost. In particular, multiple analog radio frequency (RF) chains are required at both the transmitter and the receiver, thereby leading to a higher implementation cost, more power consumption, and lower energy efficiency. This paper presents a receiver with only one RF chain for 2x2 MIMO transmission system. Proposed design is based on a time modulated antenna array (TMAA) with beam-steering functionality and a wideband software defined radio (SDR). Spatial streams were created by demultiplexing spectral components (sidebands) generated by periodical ON/OFF switching Number of RF chains was reduced from 2 to 1 while maintaining sufficiently low correlation of spatial streams, which is required to perform MIMO transmission. Feasibility of proposed technique is evaluated by means of experimental verification.

关键词： antenna array adaptive antenna 4D array time modulated antenna array beam-steering multiple-input multiple-output

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