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Analysis of Panel Antenna Arrays in Los MIMO System

IEEE ACCESS 2018年 6卷 23303-23315页

作者： Li, Rui He, Shiwen Huang, Yongming Li, Yuanjie Yang, Luxi Southeast Univ Sch Informat Sci & Engn Nanjing 210096 Jiangsu Peoples R China Cent South Univ Sch Informat Sci & Engn Changsha 410083 Hunan Peoples R China Southeast Univ Sch Informat Sci & Engn State Key Lab Millimeter Waves Nanjing 210096 Jiangsu Peoples R China Southeast Univ Natl Mobile Commun Res Lab Sch Informat Sci & Engn Nanjing 210096 Jiangsu Peoples R China Huawei Technol Co Ltd Dept Wireless RAN Res Shanghai 201206 Peoples R China

In this paper, we investigate the design of multiple panel arrays (MPAs) in line of sight (LoS) multiple-input-multiple-output (MIMO) communication systems. We utilize the spherical-wave model for the LoS channel component. The fundamental relations among key design parameters in MPAs LoS MIMO system are studied to obtain the maximum spatial multiplexing gain according to the effective degrees of freedom and channel capacity. We further analyze the performance of MPAs system when the array size and transmission distance are not matched and propose an algorithm to optimize the location of antennas. Numerical results indicate that the proposed algorithm can reduce the computational load compared with the exhaustive approach for the similar system performance. Moreover, the optimized panel antenna array is robust to the geometrical change, misplacement, and signal-to-noise-ratio.

关键词： Line of sight multiple-input multiple-output multiple panel arrays antenna locations optimization effective degrees of freedom

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Pairwise Error Probability Analysis of Dual Hop Relaying Network over Time Selective Nakagami-m Fading Channel with Imperfect CSI and Node Mobility

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TRAITEMENT DU SIGNAL 2019年第3期36卷 281-295页

作者： Shankar, Ravi Kumar, Indrajeet Mishra, Ritesh Kumar Madanapalle Inst Technol & Sci Madanapalle 517325 India Natl Inst Technol Patna Patna 800005 Bihar India

We investigate the end-to-end performance of the selective decode and forward (S-DF) relaying network over time selective independent but not necessarily identically distributed (i.n.i.d.) Nakagami-m fading channel considering practical communication constraints such as mobile nodes and imperfect channel state information (CSI). The per block average pairwise error probability (PEP) is investigated for both optimal and equal power allocation scenarios. Simulation results have been presented for various values of fading severity parameter and channel variance. The end-to-end performance is examined for various node mobility scenarios and for various antenna configurations at the source, relay and destination nodes. Simulation results confirm the accuracy of the analytical results.

关键词： selective decode-and-forward multiple-input multiple-output channel state information diversity order signal to noise ratio

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Secrecy enhancement in MIMO-OFDM-IM systems with limited RF chains

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PHYSICAL COMMUNICATION 2019年 35卷 100706-000页

作者： Gao, Zhenzhen Shen, Di Liao, Xuewen Xi An Jiao Tong Univ Dept Informat & Commun Engn Xian 710049 Shaanxi Peoples R China

A physical layer security scheme is proposed to resist eavesdropping of a multiple-input multiple-output (MIMO) system using orthogonal frequency-division multiplexing with index modulation (OFDM-IM) in the presence of a multiple-antenna passive eavesdropper, where limited number of radio frequency (RF) chains is required and additional bits are conveyed through the indices of activated transmit antennas. The secure transmission against eavesdropping is achieved by injecting artificial noise (AN) in the frequency and spatial domains. When 2 RF chains are used, the structure of quadrature spatial modulation (QSM) is exploited. The generated OFDM-IM symbols are split into two orthogonal parts, and precoded ANs are injected into each part to produce combined symbols for transmission. The secure scheme is extended to general scenarios when other number of RF chains are available based on the idea of generalized spatial modulation (GSM) and AN. The secrecy rates of the proposed schemes are analyzed, and a closed-form approximation for the ergodic secrecy rate is derived to reduce the computation complexity. The power allocation ratio and design parameters are discussed through numerical simulations. Compared to the existing secure OFDM-IM scheme (modified for MIMO systems), the proposed secure MIMO OFDM-IM shows better performance against eavesdropping when the eavesdropping and legitimate links have the same channel quality and the eavesdropping-legitimate channel correlation is considered. When 2 RF chains are available, the secure scheme based on QSM is recommended since it outperforms the secure scheme based on GSM with 2 RF chains. (C) 2019 Elsevier B.V. All rights reserved.

关键词： Orthogonal frequency division multiplexing Index modulation multiple-input multiple-output Physical layer security

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A low complexity semidefinite relaxation for large-scale MIMO detection

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JOURNAL OF COMBINATORIAL OPTIMIZATION 2018年第2期35卷 473-492页

作者： Nayak, Rupaj Kumar Biswal, Mahendra Prasad Int Inst Informat Technol Dept Math Bhubaneswar Orissa India Indian Inst Technol Dept Math Kharagpur W Bengal India

Many wireless communication problems is based on a convex relaxation of the maximum likelihood problem which further can be cast as binary quadratic programs (BQPs). The two standard relaxation methods that are widely used for solving general BQPs such as spectral methods and semidefinite programming problem (SDP), each have their own advantages and disadvantages. It is widely accepted that small and medium sized SDP problems can be solved efficiently by interior point methods. Albeit, semidefinite relaxation has a tighter bound for large scale problems, but its computational complexity is high. However, Row-by-Row method (RBR) for solving SDPs could be opted for an alternative for large-scale MIMO detection because of low complexity. The present work is a spectral SDP-cut formulation to which the RBR is applied for large-scale MIMO detection. A modified RBR algorithm with tighter bound is presented to specify the efficiency in detecting massive MIMO.

关键词： multiple-input multiple-output Maximum likelihood detection Semidefinite relaxation Spectral cut Row-by-Row method

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Doppler Spread Estimation in MIMO Frequency-Selective Fading Channels

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2018年第3期17卷 1951-1965页

作者： Mohammadkarimi, Mostafa Karami, Ebrahim Dobre, Octavia A. Win, Moe Z. Mem Univ Newfoundland Dept Elect & Comp Engn St John NF A1C 5S7 Canada MIT Informat & Decis Syst Lab Cambridge MA 02139 USA

One of the main challenges in high-speed mobile communications is the presence of large Doppler spreads. Thus, accurate estimation of maximum Doppler spread (MDS) plays an important role in improving the performance of the communication link. In this paper, we derive the data-aided (DA) and non-data-aided (NDA) Cramer-Rao lower bounds (CRLBs) and maximum likelihood estimators (MLEs) for the MDS in multiple-input multiple-output (MIMO) frequency-selective fading channel. Moreover, a low-complexity NDA-moment-based estimator (MBE) is proposed. The proposed NDA-MBE relies on the second-and fourth-order moments of the received signal, which are employed to estimate the normalized squared autocorrelation function of the fading channel. Then, the problem of MDS estimation is formulated as a non-linear regression problem, and the least-squares curve-fitting optimization technique is applied to determine the estimate of the MDS. This is the first time in the literature, when DA- and NDA-MDS estimation is investigated for MIMO frequency-selective fading channel. Simulation results show that there is no significant performance gap between the derived NDA-MLE and NDA-CRLB, even when the observation window is relatively small. Furthermore, the significant reduced-complexity in the NDA-MBE leads to low root-mean-square error over a wide range of MDSs, when the observation window is selected large enough.

关键词： Maximum Doppler spread data-aided non-data-aided multiple-input multiple-output frequency-selective Cramer-Rao lower bound (CRLB) fourth-order moment autocorrelation non-linear regression maximum likelihood estimator (MLE)

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Spectral-Efficient Generalized Spatial Modulation Based Hybrid Dimming Scheme With LACO-OFDM in VLC

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IEEE ACCESS 2018年 6卷 41153-41162页

作者： Wang, Tengjiao Yang, Fang Cheng, Ling Song, Jian Tsinghua Univ Beijing Natl Res Ctr Informat Sci & Technol Dept Elect Engn Beijing 100084 Peoples R China Tsinghua Univ Shenzhen Res Inst Key Lab Digital TV Syst Guangdong Prov & Shenzhen Shenzhen 518057 Peoples R China Univ Witwatersrand Sch Elect & Informat Engn ZA-2000 Johannesburg South Africa

Visible light communication (VLC) is regarded as one of the promising candidates to complement the conventional radio frequency communication as it can potentially perform communication and illumination simultaneously. Recently, VLC is combined with the generalized spatial modulation (GenSM) technology to improve spectral and energy efficiencies. In order to provide high-speed communication and flexible dimming control simultaneously, in this paper, a spectral-efficient GenSM-based hybrid dimming scheme with layered asymmetrically clipped optical OFDM is proposed for VLC, which combines the spatial-domain and time-domain dimming strategies. The channel capacities of the proposed scheme are analyzed and the closed-form expressions of the channel capacity are derived in both the rich scattering scenario and highly correlated scenario. According to the required illumination level, the spatial-domain and time-domain strategies are realized based on the maximization of the channel capacity. Simulation results substantiate the superior performance of the proposed dimming scheme over the state-of-art dimming schemes.

关键词： Channel capacity optimization generalized spatial modulation hybrid dimming control multiple-input multiple-output visible light communication

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Six-Mode Seven-Core Fiber for Repeated Dense Space-Division multiplexing Transmission

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2018年第5期36卷 1226-1232页

作者： Sakamoto, Taiji Saitoh, Kunimasa Saitoh, Shota Shibahara, Kohki Wada, Masaki Abe, Yoshiteru Urushibara, Azusa Takenaga, Katsuhiro Mizuno, Takayuki Matsui, Takashi Aikawa, Kazuhiko Miyamoto, Yutaka Nakajima, Kazuhide NTT Corp NTT Access Networks Serv Syst Labs Tsukuba Ibaraki 3050805 Japan Hokkaido Univ Grad Sch Informat Sci & Technol Sapporo Hokkaido 0600814 Japan Fujikura Ltd Chiba 2858550 Japan NTT Corp NTT Network Innovat Labs Yokosuka Kanagawa 2390847 Japan

We propose the optimum design of high spatial density few-mode multicore fiber (MCF) for repeated space-division multiplexed (SDM) transmission. Numerical analyses reveal that a hexagonally arranged six-mode seven-core structure is potentially better than the other possibility, the six-mode multicore structure, in terms of realizing high spatial density and low mode-dependent loss (MDL) characteristics at the splice point;its benefits will enable us to construct long-haul dense SDM transmission links. We fabricate a 171 mu m cladding six-mode seven-core fiber and successfully demonstrate low loss, differential mode delay (DMD), crosstalk, and splice-induced MDL characteristics while maintaining the relative core multiplicity factor of more than 50. Finally, we demonstrate repeated optical 12 x 12 MIMO transmission of more than 100 km using our six-mode MCF and erbium doped fiber amplifier (EDFA).

关键词： Mode dependent loss multi-core fiber multiple-input multiple-output

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Blind recognition of space time block code in MIMO systems

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DIGITAL SIGNAL PROCESSING 2018年 83卷 1-8页

作者： Chung Buiquang Zhang, Tianqi Univ Sci & Technol China Sch Informat Sci & Technol Hefei Anhui Peoples R China Chongqing Univ Post & Telecommun Sch Commun & Informat Engn Chongqing Peoples R China

Space time block code (STBC) and vertical Bell layered space-time (VBLAST) signals are widely applied in multiple-input multiple-output (MIMO) systems, and one essential step in the signal interception process is to recognize STBC/VBLAST. As the STBC signal is correlated in time, it has a specific cyclic frequency in higher-order cyclic accumulation, while the VBLAST signal emitted from different antenna is uncorrelated. According to this property, this paper proposes a blind recognition approach for STBC/VBLAST signals based on fourth-order cyclic accumulation (FCC). The recognition process is divided into two steps. In the first step, we first establish the correlation choosing criteria that makes sure all correlations of STBC can generate a statistically cyclic sequence. The cyclic statistic then is estimated by combining the FCC with channel information that provides the peaks phase of the statistically cyclic sequence. The second step compares the estimated cyclic statistic with a detection threshold, which is obtained by given a probability of false alarms. The proposed approach avoids the need for any prior knowledge of the transmitted signal, and can work well in the lowly SNR by employing the advantages of FCC. (C) 2018 Elsevier Inc. All rights reserved.

关键词： Space time block code Vertical Bell layered space time code multiple-input multiple-output Fourth-order cyclic accumulation Blind recognition

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Modeling and realization of mobile-to-mobile wideband MIMO channels based on the geometrical multi-ring and multi-ellipse stochastic scattering model

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The Journal of China Universities of Posts and Telecommunications 2018年第5期25卷 39-48页

作者： Liang Xiaolin Cao Wangbin Zhao Xiongwen School of Electronic and Information Engineering Hebei UniversityBaoding 071002 China School of Electrical and Electronic Engineering North China Electric Power University Baoding 071000 China School of Electrical and Electronic Engineering North China Electric Power University Beijing 102206 China

A geometry-based stochastic scattering model （GBSSM） based on geometrical multiple rings and ellipses is proposed for wideband multiple-input multiple-output （MIMO） mobile-to-mobile （M2M） fading channels. The proposed GBSSM is deployed with cross-polarized antennas and can be applied for the line-of-sight （LOS） and non- LOS （NLOS） scenarios by considering the single-bounced （SB） and double-bounced （DB） components. The channel realization is much more straightforward and concise to study the channel characteristics compared with the too complicated analytical solutions available so far. Based on the proposed GBSSM and realized channel, the channel characteristics and parameters at 2 GHz and 5 GHz with 100 MHz bandwidth are further investigated. The results can be used in the link and system level simulations in M2M radio systems.

关键词： cross-polarized antennas mobile-to-mobile multiple-input multiple-output multl-rlng and multi-ellipse wideband channels

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An investigation of S-DF cooperative communication protocol over keyhole fading channel

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PHYSICAL COMMUNICATION 2018年 29卷 120-140页

作者： Shankar, Ravi Mishra, Ritesh Kumar Natl Inst Technol Elect & Commun Engn Dept Patna Bihar India

This paper investigates the keyhole or pinhole effect on the pairwise error probability (PEP) performance of the multiple-input multiple-output (MIMO) space-time block-code (STBC) based selective decode and forward (S-DF) protocol. The closed form PEP expressions are derived for several configurations in terms of number of hops, phases, and relays over Nakagami-m fading channel, with perfect and imperfect channel state information (CSI), and with and without the keyhole condition. Further, a framework is developed for deriving the diversity order (DO) for each configuration. It demonstrates that full DO for cooperation protocol can be achieved when there is a knowledge of perfect CSI. A convex optimization framework is formulated for obtaining the optimal source-relay power allocation factors which significantly improve the end-to-end reliability of the system under power constraint scenarios. Monte Carlo simulations are performed for both equal and optimal power allocation factors and results show the substantial improvement in PEP performance with an increase in the value of the shape parameter and relay to destination (RD) link channel variance. Results show an improved PEP performance by increasing the RD link channel variance in comparison to increasing the source to relay (SR) link channel variance. Also PEP performance degrades for keyhole Nakagami-m fading channel as compared to Nakagami-m fading channel. Simulation results are in close agreement with the analytical results at high signal to noise ratio (SNR) regimes. (C) 2018 Elsevier B.V. All rights reserved.

关键词： Monte Carlo simulation Keyhole effects Pairwise error probability Channel state information Selective decode and forward multiple-input multiple-output Space-time block-code

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