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Embedded space-time codes for multiple-input-multiple-output systems in Rayleigh fading

IET COMMUNICATIONS 2015年第13期9卷 1615-1618页

作者： Norouzi, Mandana Wu, Yuteng Attang, Edidiong Ellis, Robert B. Atkin, Guillermo IIT Dept Elect & Comp Engn Chicago IL 60616 USA IIT Dept Appl Math Chicago IL 60616 USA

In this study, novel designs of embedded space-time multiplexing codes are presented. The space-time codes are constructed initially based on the decomposition of normal matrices that produce diagonal structures. The eigenvalue decomposition of circulant matrices, a type of normal matrices, can generate these codes. A key constraint in the design is that only the diagonal matrices are function of data. Since the components of the diagonal matrix are linear combinations of the data, the codes are called embedded. These codes provide an embedded diversity, full rate and enable multi-user applications with reduced interference. Later constructions in Galois fields are used to reduce the constellations expansion introduced by the dependency of the eigenvalues of the diagonal matrix to the data. The pairwise error probability for the codes is derived. Performance of the codes based on simulation and theoretical analysis, are compared with the conventional spatial-multiplexing codes and other complex orthogonal designs. Simulation results demonstrate the advantage of the proposed codes. Simulation has been done for Rayleigh-fading channels with known channel-state information.

关键词： space-time codes Rayleigh channels Galois fields matrix algebra MIMO communication embedded space-time multiplexing codes multiple-input-multiple-output systems Rayleigh fading channel normal matrices diagonal structures eigenvalue decomposition circulant matrices Galois fields pairwise error probability complex orthogonal designs

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Performance analysis of multi-antenna selection policies using the golden code in multiple-input multiple-output systems

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IET COMMUNICATIONS 2014年第12期8卷 2147-2152页

作者： Ge, Lu Chen, Gaojie Gong, Yu Chambers, Jonathon Univ Loughborough Adv Signal Proc Grp Commun Div Sch Elect Elect & Syst Engn Loughborough Leics England

In multiple-input multiple-output (MIMO) systems, multiple-antenna selection has been proposed as a practical scheme for improving the signal transmission quality as well as reducing realisation cost because of minimising the number of radio-frequency chains. In this study, the authors investigate transmit antenna selection for MIMO systems with the Golden Code. Two antenna selection schemes are considered: max-min and max-sum approaches. The outage and pairwise error probability performance of the proposed approaches are analysed. Simulations are also given to verify the analysis. The results show the proposed methods provide useful schemes for antenna selection.

关键词： MIMO communication transmitting antennas cost reduction Gold codes error statistics multiantenna selection policies golden code multiple-input-multiple-output systems MIMO systems multiple-antenna selection signal transmission quality improvement cost reduction radio-frequency chains transmitting antenna selection error probability

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Low-complexity soft-interference cancellation turbo equalisation for multi-input-multi-output systems with multilevel modulations

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IET COMMUNICATIONS 2015年第5期9卷 728-735页

作者： Wu, Jingxian Wang, Longbao Xiao, Chengshan Univ Arkansas Dept Elect Engn Fayetteville AR 72701 USA Missouri Univ Sci & Technol Dept Elect Comp Engn Rolla MO 65409 USA

This study presents a low-complexity soft-interference cancellation equaliser (SICE) for the turbo detection of multiple-input-multiple-output systems operating in time dispersive channels. The SICE contains three time-invariant linear filters: a feedforward filter, a causal feedback filter and an anti-causal feedback filter. The feedforward filter is designed to suppress the intersymbol interference because of channel time dispersion and the multiplexing interference from multiple transmit antennas. The causal (or anti-causal) feedback filter is developed to remove the residual interference caused by the symbols transmitted before (or after) the symbol under detection. The filters are designed by analysing the statistical properties of soft decisions. The performance of the proposed SICE is verified through both extrinsic information transfer (EXIT) chart analysis and computer simulations. The EXIT chart analysis shows that, because of the inclusion of the anti-causal soft decision, the SICE performance approaches the ideal matched filter bound as the iteration progresses. Consequently, the proposed SICE achieves significant performance gains over conventional equalisers.

关键词： interference suppression MIMO communication intersymbol interference transmitting antennas multilevel modulations low-complexity soft-interference cancellation equaliser turbo detection multiple-input-multiple-output systems time dispersive channels time-invariant linear filters feedforward filter anti-causal feedback filter intersymbol interference channel time dispersion multiplexing interference transmit antennas extrinsic information transfer chart analysis computer simulations

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Adaptive iterative learning reliable control for a class of non-linearly parameterised systems with unknown state delays and input saturation

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IET CONTROL THEORY AND APPLICATIONS 2016年第17期10卷 2160-2174页

作者： Ji, Honghai Hou, Zhongsheng Fan, Lingling Lewis, Frank L. Beijing Jiaotong Univ Adv Control Syst Lab Beijing 100044 Peoples R China Beijing Jiaotong Univ Sch Elect & Informat Engn Beijing 100044 Peoples R China Univ Texas Arlington UTA Res Inst Ft Worth TX USA Northeastern Univ State Key Lab Synthet Automat Proc Ind Shenyang Peoples R China

An adaptive iterative learning reliable control (AILRC) strategy is developed in this study for a class of non-linearly parameterised systems subject to unknown time-varying state delays and input saturation as well as actuator faults. In regard to non-linearly parameterised uncertainties, not only the non-linearly parameterised controlled object, but also the non-linearly parameterised input distribution matrix is investigated in this technical note. Without the need for precise system parameters or analytically estimating bound on actuator faults variables, the novel data-driven AILRC is constructed by a non-linear feedback term and a robust term. The non-linear influence brought by actuator faults, input saturation and state delays can be compensated with the resultant algorithms. It is shown that the L-[0,T](2) convergence of single-input-single-output and multiple-input-multiple-output systems is proved through a new time-weighted Lyapunov-Krasovskii-like composite energy function. The validity of the proposed AILRC is further verified by simulation.

关键词： nonlinear control systems iterative learning control adaptive control uncertain systems time-varying systems delays actuators fault tolerant control matrix algebra convergence MIMO systems Lyapunov methods adaptive iterative learning reliable control unknown time-varying state delays input saturation nonlinearly parameterised uncertainties actuator faults variables distribution matrix data-driven AILRC feedback term robust term convergence single-input-single-output systems multiple-input-multiple-output systems MIMO systems time-weighted Lyapunov-Krasovskii-like composite energy function

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Study on isolation improvement between closely-packed patch antenna arrays based on fractal metamaterial electromagnetic bandgap structures

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IET MICROWAVES ANTENNAS & PROPAGATION 2018年第14期12卷 2241-2247页

作者： Alibakhshikenari, Mohammad Virdee, Bal S. See, Chan H. Abd-Alhameed, Raed Ali, Ammar Hussein Falcone, Francisco Limiti, Ernesto Univ Roma Tor Vergata Dept Elect Engn Via Politecn 1 I-00133 Rome Italy London Metropolitan Univ Ctr Commun Technol Sch Comp & Digital Media London N7 8DB England Univ Bolton Sch Engn Dept Deane Rd Bolton BL3 5AB England Univ Bradford Sch Elect Engn & Comp Sci Bradford BD7 1DP W Yorkshire England Univ Publ Navarra Elect & Elect Engn Dept Navarra 31006 Spain

A decoupling metamaterial (MTM) configuration based on fractal electromagnetic-bandgap (EMBG) structure is shown to significantly enhance isolation between transmitting and receiving antenna elements in a closely-packed patch antenna array. The MTM-EMBG structure is cross-shaped assembly with fractal-shaped slots etched in each arm of the cross. The fractals are composed of four interconnected-Y-shaped' slots that are separated with an inverted-T-shaped' slot. The MTM-EMBG structure is placed between the individual patch antennas in a 2x2 antenna array. Measured results show the average inter-element isolation improvement in the frequency band of interest is 17, 37 and 17dB between radiation elements #1 & #2, #1 & #3, and #1 & #4, respectively. With the proposed method there is no need for using metallic-via-holes. The proposed array covers the frequency range of 8-9.25GHz for X-band applications, which corresponds to a fractional-bandwidth of 14.5%. With the proposed method the edge-to-edge gap between adjacent antenna elements can be reduced to 0.5(0) with no degradation in the antenna array's radiation gain pattern. Across the array's operating band, the measured gain varies between 4 and 7dBi, and the radiation efficiency varies from 74.22 and 88.71%. The proposed method is applicable in the implementation of closely-packed patch antenna arrays used in SAR and MIMO systems.

关键词： energy gap microstrip antenna arrays fractal antennas metamaterial antennas microwave metamaterials antenna radiation patterns slot antenna arrays transmitting antennas receiving antennas average interelement isolation improvement closely-packed patch antenna arrays fractal metamaterial electromagnetic bandgap structures decoupling metamaterial configuration decoupling MTM configuration transmitting antenna elements receiving antenna elements MTM-EMBG structure cross-shaped assembly fractal-shaped slots interconnected-Y-shaped slots inverted-T-shaped slot radiation gain pattern radiation efficiency measured gain synthetic aperture radar multiple-input-multiple-output systems frequency 8 GHz to 9 25 GHz efficiency 74 22 percent efficiency 88 71 percent

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Block-ordered layered detector for MIMO-STBC combined with transmit and receive eigen-beamformers

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IEICE TRANSACTIONS ON COMMUNICATIONS 2004年第9期E87B卷 2747-2756页

作者： Lee, WC Kim, HC Soongsil Univ Sch Elect Engn Seoul South Korea

This paper proposes the joint beamforming space-time block coding (JBSTBC) scheme for multi-input multi-output (MIMO) communication systems. To enhance the order of spatial diversity in presence of deteriorate fading correlations as well as inter-substream interferences, the proposed JBSTBC method employs joint eigen-beamforming technique together with the block-ordered layered detector (BOLD) for MIMO-STBC. In order to confirm the superiority of the proposed JBSTBC method, computer simulations are conducted in highly correlated fading situations while providing detailed mathematical derivations for clarifying functionality of the proposed scheme.

关键词： multiple-input-multiple-output systems eigen-beamformer space-time block coded scheme spatial diversity

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Feedforward model predictive control of a non-linear solar collector plant with varying delays

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IET CONTROL THEORY AND APPLICATIONS 2010年第8期4卷 1421-1435页

作者： Brus, L. Wigren, T. Zambrano, D. Uppsala Univ Dept Informat Technol SE-75105 Uppsala Sweden

This study discusses non-linear optimal feedforward control of solar collector plants. The control problem is challenging, with non-linear disturbance effects and long input-dependent transport delays. The controller operates in a model-based predictive control framework, without feedback and constraints, to highlight feedforward controller performance gains. To reduce the computational complexity state extension is avoided when modelling the time delays. The motivation for this is provided by a proof of the equivalence between state extension and direct prediction in optimal control, for non-linear multiple-input-multiple-output (MIMO) systems with time delays in disturbances and controls. The solar collector controller also uses flow-dependent sampling to reduce the time variation of the delays. To obtain an accurate model for feedforward controller design, a black-box recursive prediction error identification algorithm was used for modelling of the non-linear plant using measured data. Experimentally, accurate feedforward control was obtained when the controller design was tested with simulation, using measured disturbances from the plant. About two-thirds of the control effort needed appears to be available by feedforward control only. In order to evaluate the algorithms in difficult conditions, the evaluation was performed on data obtained during a day with partly cloudy weather. This caused large flow variations, and consequently large time delay variations.

关键词： error identification algorithm Other topics in statistics Power system control multiple-input-multiple-output systems Computational complexity feedforward controller design Control of electric power systems Multivariable control systems predictive control computational complexity control system synthesis power system control flow-dependent sampling solar collector plant Control system analysis and synthesis methods Nonlinear control systems MIMO systems input-dependent transport delays Solar power stations and photovoltaic power systems feedforward sampling methods delays black-box recursive prediction nonlinear control systems recursive estimation Optimal control nonlinear disturbance effects feedforward model predictive control solar power stations time delays optimal control Distributed parameter control systems state extension

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ELECTRONICS LETTERS 2015年第7期51卷 587-588页

作者： Shen, Wenqian Dai, Linglong Gao, Zhen Wang, Zhaocheng Tsinghua Univ Dept Elect Engn Tsinghua Natl Lab Informat Sci & Technol Beijing 100084 Peoples R China

Downlink channel estimation with low pilot overhead is an important and challenging problem in massive multiple-input-multiple-output (MIMO) systems due to the substantially increased MIMO channel dimension. A block iterative support detection (block-ISD)-based algorithm for down-link channel estimation to reduce the pilot overhead is proposed, which is achieved by fully exploiting the block sparsity inherent in the block-sparse equivalent channel derived from the spatial correlations of MIMO channels. Furthermore, unlike conventional compressive sensing (CS) algorithms that rely on prior knowledge of the sparsity level, block-ISD relaxes this demanding requirement and is thus more practically appealing. Simulation results demonstrate that block-ISD yields better normalised mean square error (NMSE) performance than classical CS algorithms, and achieve a reduction of 84% pilot overhead compared with conventional channel estimation techniques.

关键词： MIMO communication channel estimation iterative methods mean square error methods CS algorithms NMSE performance better normalised mean square error performance block iterative support detection block sparsity block-ISD-based algorithm block-sparse equivalent channel downlink channel estimation large-scale MIMO systems low pilot overhead multiple-input-multiple-output systems spatially correlated channel estimation

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Quarter cylindrical dielectric resonator antenna with circular polarisation for wideband MIMO systems

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ELECTRONICS LETTERS 2020年第4期56卷 174-175页

作者： Belazzoug, M. Messaoudene, I. Aidel, S. Denidni, T. A. Kishk, A. A. Univ Bordj Bou Arreridj Lab Elect & Telecommun Avancees Bordj Bou Arreridj Algeria Inst Natl Rech Sci Montreal PQ H5A1C6 Canada Concordia Univ Dept Elect & Comp Engn Montreal PQ H3G 1M8 Canada Ecole Natl Super Informat ESI Ex INI BP 68M Algiers Algeria

In this Letter, a quarter cylindrical dielectric resonator antenna (Q-CDRA) with a low profile and circular polarisation (CP) is presented for wideband and multiple-input-multiple-output (MIMO) systems. The approach used to obtain a reduced wideband CP antenna is realised by deforming the geometry of the CDR to a quarter cylinder and using a quasi-spiral feedline to excite two resonant modes in phase quadrature (HEM(11)and HEM12). The proposed design exhibits a wide-impedance bandwidth (BW) of 34% (4.4-6.2 GHz) with a low measured coupling level<-15 dB, and an axial ratio BW of 24.4% (4.5-5.75 GHz). The antenna gain is stable through the operating BW with a gain peak of 6.4 dBi. In addition, the antenna has a low cross-polarisation in the boresight direction with low envelope correlation coefficient<0.03. The presented design is suitable for RHCP WLAN applications.

关键词： MIMO communication microstrip antennas antenna feeds microwave antennas antenna radiation patterns wireless LAN dielectric resonator antennas electromagnetic wave polarisation broadband antennas quarter cylindrical dielectric resonator antenna circular polarisation wideband MIMO systems multiple-input-multiple-output systems reduced wideband CP antenna resonant modes low measured coupling level antenna gain low cross-polarisation quasi-spiral feedline phase quadrature boresight direction RHCP WLAN applications frequency 4 4 GHz to 6 2 GHz frequency 4 5 GHz to 5 75 GHz

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Downlink training scheme for massive MIMO systems

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ELECTRONICS LETTERS 2015年第24期51卷 2059-2060页

作者： Qian, Chen Wang, Zhaocheng Dai, Linglong Chen, Jinhui Sun, Chen Tsinghua Univ Dept Elect Engn Tsinghua Natl Lab Informat Sci & Technol Beijing 100084 Peoples R China Sony China Res Lab Beijing 100084 Peoples R China

A novel downlink training scheme is proposed for time-division duplex massive MIMO systems. Different from conventional solutions, including the cell-specific reference signal in LTE, the UE-specific reference signal in LTE-A and the commonly used method without the downlink training sequence, the cell-specific demodulation reference signal is proposed by utilising the inherent asymptotic orthogonality, which is shared by all users within one cell and used for the estimation of effective channel coefficients. The training overhead is reduced and the downlink spectral efficiency can be improved considerably.

关键词： MIMO communication Long Term Evolution demodulation channel estimation wireless channels cellular radio downlink training scheme massive MIMO system UE-specific reference signal LTE-A cell-specific demodulation reference signal asymptotic orthogonality channel coefficient estimation training overhead reduction downlink spectral efficiency time-division duplex multiple-input-multiple-output systems TDD scheme

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