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49th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)

作者： Miao, Xuan-Wei Zheng, Sheng-Yuan Torkaman, Pouya Feng, Kai-Ming Yang, Shang-Hua Natl Tsing Hua Univ Inst Elect Engn Hsinchu Taiwan Natl Tsing Hua Univ Inst Photon Technol Hsinchu Taiwan

ISBN: (纸本)9798350370331;9798350370324

This study investigates the performance of a multi-channel access solution based on a robust terahertz indoor communication system at 325 GHz with a single-input, single-output (SISO) system. Spatial diversity builds up the possibility of transmission under various channel conditions. The wireless terahertz system comprises a vibration mirror, a blocking object, two motorized stages, and two lenses. The system imitates the actual communication scenarios affected by blockage and misalignment. We adopted three multi-channel strategies: (1) Line-of-sight transmission (2) Reflection transmission (3) Blockage along LOS transmission. With experimental results, we validate our analysis and successfully show that the multi-channel strategies can significantly improve transmission. The SISO system can have a coverage of 115 degrees with a wireless distance of 1.5 meters. The results greatly impact the applications of terahertz indoor communications and provide a physical solution for various transmission conditions.

关键词： Terahertz communication Multi-channel Access single-input single-output system

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On feasibility of linear interference alignment for single-input-single-output multi-frequency interference channel

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IET COMMUNICATIONS 2014年第12期8卷 2207-2212页

作者： Du, Guang-long Zou, Wei-xia Zhou, Zheng Liu, Jian-han Beijing Univ Posts & Telecommun Key Lab Univ Wireless Commun MOE Beijing 100876 Peoples R China MediaTek Inc San Jose CA USA

This study explores the feasibility of linear interference alignment (IA) for a (M x M, 1)(K) system with multi-frequency independent channels. The authors prove that number of users K <= 2M - 2 is a necessary condition for (M x M, 1)(K) multi-frequency IA system, which is less than that of (M x M, 1)(K) multiple-input-multiple-output system (i.e. K <= 2M - 1). The conclusion can be extended to all cases with the diagonal channel matrix. They also reveal that the traditional frequency division multiplexing method is inefficient in spectrum utilisation. They apply max-SINR (signal to interference plus noise ratio) and iterative IA algorithms and the author's simulation results verify that IA algorithms work well in (M x M, 1)(2M-2) IA system.

关键词： radio networks radiofrequency interference matrix algebra linear interference alignment single-input single-output system multifrequency interference channel multifrequency interference alignment system diagonal channel matrix

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Performance evaluation and comparison of spatial modulation and non-DC MIMO m-CAP techniques in indoor VLC system

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IET OPTOELECTRONICS 2019年第6期13卷 281-287页

作者： Nassiri, Mahdi Ashouri, Saeed Baghersalimi, Gholamreza Ghassemlooy, Zabih Univ Guilan Dept Elect Engn Rasht Iran Northumbria Univ Fac Engn & Environm Opt Commun Res Grp Newcastle Upon Tyne Tyne & Wear England

Here, the authors propose and apply two novel schemes of multi-band carrierless amplitude and phase (m-CAP) modulation for spatial modulation (SM)-based visible light communications (VLC) systems. In SM, both spatial and signal constellation are utilised to improve the performance of the m-CAP system. Here, they have adopted the non-DC m-CAP which is a power efficient technique with no DC-bias. The bit error rate (BER) performance and the spectral efficiency of the proposed systems are compared with single-input single-output (SISO) and multiplexing multiple-input multiple-output (MIMO) m-CAP systems. Results demonstrate that non-DC m-CAP, with the same spectral efficiency as that of SISO m-CAP, outperforms other schemes in terms of BER due to its power efficiency;however, a higher spectral efficiency can be achieved by the SM-MIMO m-CAP scheme.

关键词： MIMO communication error statistics SISO communication indoor radio multiplexing phase modulation amplitude modulation free-space optical communication optical modulation signal constellation power efficient technique bit error rate performance indoor VLC system phase modulation single-input single-output system spectral efficiency spatial modulation-based visible light communications systems SM-MIMO systems nonDC MIMO m-CAP techniques BER performanc SISO multiplexing multiple-input multiple-output system

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Design of a high-frequency (3-30 MHz) multiple-input multiple-output system resorting to polarisation diversity

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IET MICROWAVES ANTENNAS & PROPAGATION 2011年第11期5卷 1310-1318页

作者： Ndao, P. M. Erhel, Y. Lemur, D. Le Masson, J. Univ Rennes 1 Inst Elect & Telecommun Rennes F-35042 Rennes France Ecoles Coetquidan St Cyr Ctr Rech F-56381 Guer France

This study presents a multiple-input multiple-output (MIMO) architecture utilising polarisation diversity to increase the capacity of high-frequency (HF) radio links through the ionospheric channel. A summary of physics focuses on the polarisation of radio waves propagated in the ionosphere. This preliminary step introduces the original idea of diversity in the transmitted polarisations to replace the classical space diversity for MIMO applications. This solution enables a reduction of the inter antenna spacing which is convenient in the context of decametric wavelengths. Simulations, referring to the theoretical expression of channel capacity and involving realistic models of ionospheric radio links, underline a significant increase in performances for this particular MIMO structure if compared to a single-input single-output system. Additionally, the trade-off between capacity gain and complexity appears balanced with the development of a 2 x N MIMO system transmitting two complementary circular polarisations. More specifically, the design of a 2 x 2 MIMO system is described in the context of a single carrier waveform and frequency-domain equalisation, resorting to classical solutions for the different signal processing modules. A global simulation, involving the entire transmission system, is carried out and gives an estimate of the maximal data transfer rate compatible with a requested quality of service.

关键词： high-frequency multiple-input multiple-output system circular polarisations ionospheric channel frequency-domain equalisation single-carrier waveform classical space diversity polarisation diversity capacity gain ionospheric radio links single-input single-output system Signal processing and detection frequency 3 MHz to 30 MHz radiowave polarisation quality of service electromagnetic wave polarisation radiowave propagation ionospheric electromagnetic wave propagation MIMO architecture diversity reception Radiowave propagation antenna spacing reduction decametric wavelengths channel capacity signal processing modules radio links equalisers data transfer rate HF radio links signal processing Radio links and equipment Communication channel equalisation and identification radiowave polarization MIMO communication

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Performance of an SC-FDE SATCOM system in Block-Time-Invariant Orthogonal MIMO Channels

Performance of an SC-FDE SATCOM System in Block-Time-Invaria...

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54th Annual IEEE Global Telecommunications Conference (GLOBECOM)

作者： Schwarz, R. T. Knopp, A. Lankl, B. Fed Off Bundeswehr Informat Management & Informat Satellite Commun Div D-56026 Koblenz Germany Munich Univ Bundeswehr Inst Commun Engn D-85579 Neuherberg Germany

ISBN: (纸本)9781424492688

A multiple-input multiple-output (MIMO) satellite communications system for fixed-satellite services (FSS) is considered. The MIMO Line-of-Sight (LOS) satellite channel is optimized to achieve maximum spectral efficiency. This requires an orthogonal MIMO channel matrix, ending up with large antenna spacing of the ground terminal antennas. As the main drawback, considerable propagation delays between the MIMO paths are observed, and the MIMO signal sub-streams interfere asynchronously in the order of several tens or hundreds of a symbol duration at the receiver. To cope with these delays, we propose a system architecture that uses a sufficiently large guard-interval or cyclic prefix between successive data blocks. The delay equalization at the receiver is then performed by a zero-forcing frequency domain equalizer for single-carrier transmission (SC-FDE). Thanks to the orthogonality of the considered MIMO channel, the SC-FDE architecture achieves even perfect spatial equalization of the multiplexed signal streams at considerably low implementation effort. The capacity reduction caused by the guard-interval is, moreover, mitigated by long data blocks, which can be used because of the long channel coherence times in FSS applications. The system concept reveals superior BER and transinformation performance, which is verified through fair comparison with current single-input single-output (SISO) systems. If the channel orthogonality is violated through narrow antenna spacing, the system performance degrades dramatically.

关键词： BER Bit error rate Downlink FSS MIMO MIMO LOS satellite channel MIMO communication MIMO line-of-sight satellite channel MIMO satellite communications system MIMO signal substreams Receiving antennas SC-FDE SC-FDE SATCOM system SISO system Satellites antenna arrays block-time-invariant orthogonal MIMO channels delay equalization equalisers error statistics fixed-satellite services ground terminal antennas matrix algebra multiple-input multiple-output satellite communications system narrow antenna spacing orthogonal MIMO channel matrix propagation delays radio receiver radio receivers satellite communication single-carrier transmission single-input single-output system spatial equalization telecommunication services wireless channels zero-forcing frequency domain equalizer

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Switching tracking control for linear time-invariant systems without overshoot: a positive systems method

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IET CONTROL THEORY AND APPLICATIONS 2019年第7期13卷 952-959页

作者： Zhang, Yaoli Zhao, Jun Northeastern Univ Coll Informat Sci & Engn Shenyang 110819 Liaoning Peoples R China Northeastern Univ State Key Lab Synthet Automat Proc Ind Shenyang 110819 Liaoning Peoples R China

In this study, the authors study the issue of how to design controllers to asymptotically track a constant signal without overshoot for linear time-invariant systems. Using the theory of positive systems, they obtain the non-negative invariant set of the output for the autonomous systems. Then, a linear state feedback controller is designed to ensure the non-overshooting tracking when the initial state is in some region. Furthermore, for a single-input single-output system, the problem of global non-overshooting tracking control is solved by a switching control law. For multi-input multi-output systems, they also obtain the non-overshooting response under some assumptions. A numerical example is given to illustrate the effectiveness of the proposed theory.

关键词： nonlinear control systems linear systems state feedback closed loop systems feedback MIMO systems control system synthesis switching systems (control) linear time-invariant systems positive systems method nonnegative invariant set autonomous systems linear state feedback controller single-input single-output system nonovershooting tracking control switching control law multiinput multioutput systems nonovershooting response

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Ergodic and outage capacity of interference temperature-limited cognitive radio multi-input multi-output channel

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IET COMMUNICATIONS 2011年第5期5卷 652-659页

作者： Kong, Asaduzzaman H. Y. Univ Ulsan Dept Elect Engn Ulsan South Korea

In this study, we consider a cognitive radio multi-input multi-output (CR-MIMO) system in which the cognitive radio (CR) users are allowed to access the spectrum of the licensed primary users, provided that interference power received at the primary receiver is less than a certain threshold. The authors investigate the effect of the MIMO diversity on such multi-constraint CR-MIMO systems. They consider peak interference power constraint at the primary receiver and peak transmit power constraint at the CR transmitter. In MIMO systems, the allowable transmit power is distributed over the transmit-antennas. The power allocation problem of such CR systems is studied under both sum power and interference constraints. The authors show that the equal power allocation does not improve the ergodic capacity but improves the outage capacity over the single-input single-output (SISO) system. Transmit antenna selection (TAS) which is a special case of power allocation is also investigated. The authors show that, under the peak interference and transmit power constraint, selecting a single transmit-antenna and allocating all the power to the selected best antenna achieves the same performance as the optimal power allocation (OPA). The authors evaluate ergodic capacity and outage capacity for both power allocation-and antenna selection-based schemes. The closed-form expressions of the outage probabilities are also derived. Results show that both OPA and TAS significantly improves the capacities over the SISO system.

关键词： Electromagnetic compatibility and interference primary receiver CR transmitter licensed primary users single-input single-output system radio transmitters wireless channels diversity reception radiofrequency interference interference temperature-limited cognitive radio transmitting antennas CR-MIMO system optimal power allocation radio receivers multiple-input multiple-output channel single antennas transmit antenna selection MIMO diversity Radio links and equipment radio spectrum management cognitive radio MIMO communication

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Set-point regulation of monotone systems using the monotone small-gain theorem

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IET CONTROL THEORY AND APPLICATIONS 2013年第3期7卷 447-454页

作者： Agahi, Hamed Yazdanpanah, Mohammad Javad Univ Tehran Coll Engn Sch Elect & Comp Engn Adv Control Syst Lab Tehran Iran Univ Tehran Coll Engn Sch Elect & Comp Engn Control & Intelligent Proc Ctr ExcellenceAdv Con Tehran Iran

Monotone dynamical systems are those with solutions preserving specific orderings, relative to the associated initial states. This study shows that, under negative output feedback control, a monotone single-input single-output system with well-defined static characteristics is able to globally asymptotically regulate its solution at desired constant set-points, while the boundedness of all solutions are successfully guaranteed. This valuable result is obtained only through limited amount of qualitative and quantitative data, which may be provided from relatively simple experiments for real applications. The design procedure, in the cast of a new theorem, is mainly derived from the specific version of Small Gain Theorem for autonomous monotone systems;which ensures the global attractivity of the desired set-point. A biological simulation example illustrates the effectiveness and applicability of the proposed control strategy.

关键词： biology control system synthesis feedback MIMO systems set-point regulation monotone small-gain theorem monotone dynamical systems negative output feedback control single-input single-output system static characteristics constant set-points qualitative data quantitative data autonomous monotone systems global attractivity biological simulation design procedure biology control system synthesis feedback MIMO systems set-point regulation monotone small-gain theorem monotone dynamical systems negative output feedback control single-input single-output system static characteristics constant set-points qualitative data quantitative data autonomous monotone systems global attractivity biological simulation design procedure

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Adaptive output-feedback finite-time stabilisation of stochastic non-linear systems with application to a two-stage chemical reactor

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IET CONTROL THEORY AND APPLICATIONS 2019年第4期13卷 534-542页

作者： Sui, Shuai Chen, C. L. Philip Liaoning Univ Technol Informat Comp Sci Jinzhou Liaoning Peoples R China Univ Macau Comp & Informat Sci Macau Peoples R China Dalian Maritime Univ Dalian 116026 Peoples R China Chinese Acad Sci Inst Automat State Key Lab Management & Control Complex Syst Beijing 100080 Peoples R China

In this study, the authors investigate the problem of the stochastically finite-time stability analysis and control design of an adaptive single-input and single-output (SISO) uncertain stochastic non-linear system via establishing a new stability criterion. Owing to the unknown dynamics and unmeasured system variables, fuzzy logic systems and a fuzzy state observer are constructed and applied to identify the stochastic system, respectively. Combining the finite-time definition, stochastic differential equation and $\hat o$o<^> formula, a novel stochastically finite-time stability theorem is raised in this study. By utilising the novel criterion and adaptive backstepping intelligent control, a stochastically finite-time control method is proposed. It is illustrated that the controlled stochastic system is semi-global finite-time stable in probability and behaves excellent convergence. The simulation results of a two-stage continuous stirred tank reactor process reveal the validity and efficiency.

关键词： chemical reactors stochastic systems control system synthesis feedback differential equations adaptive control uncertain systems observers stochastic processes nonlinear control systems stability fuzzy control control nonlinearities probability adaptive output-feedback finite-time stabilisation two-stage chemical reactor uncertain stochastic nonlinear system unmeasured system variables fuzzy logic systems fuzzy state observer stochastic differential equation adaptive backstepping intelligent control two-stage continuous stirred tank reactor process controller design single-input single-output system SISO probability

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Comparative study of stabilising methods for adaptive speed sensorless full-order observers with stator resistance estimation

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IET CONTROL THEORY AND APPLICATIONS 2010年第6期4卷 993-1004页

作者： Vicente, I. Endemano, A. Garin, X. Brown, M. Univ Manchester Sch Elect & Elect Engn Control Syst Ctr Manchester M60 1QD Lancs England

The full-order Luenberger flux (FOLO) observer combined with adaptive techniques is the most widely used method for sensorless vector-controlled drives in induction machines. These methods suffer inherently from an unstable regenerating region and the unobservable zero stator frequency operating point. Stator resistance estimation is also required in the low speed region leading to a complicated multiple-input multiple-output (MIMO) system, and a novel simplification of the MIMO system into a single-input single-output (SISO) system based on the two-time-scale approach is proposed for a simple stability analysis procedure. Four different stabilisation strategies are suggested for this comparison, based on the main stabilisation methods found in the literature. The 'augmented error signal' and the 'observer gains retuning' methods, based on the Routh-Hurwitz criterion, are used for the stabilisation of the motor speed estimator. The stator resistance stabilisation has been implemented using the 'augmented error signal' method. This has been evaluated using two different gain tuning methods, one based on the Routh-Hurwitz criterion and the other on the averaging analysis technique. The different stabilising strategies are evaluated theoretically according to the simplified SISO system open-loop transfer function zeroes and compared by simulation and extensive experiments. The suggested observer is flexible for any vector controlled drive and results have been validated in a 7.5 kW experimental test bench for rotor flux-oriented vector control (RFOC) and indirect self-control drives. The stability and behaviour of the sensorless scheme are successfully verified for all operating conditions above 0.4 Hz stator frequency.

关键词： machine vector control adaptive speed indirect self-control drives asynchronous machines multiple-input multiple-output system Control of electric power systems observer gain retuning method Multivariable control systems open-loop transfer function zeroes zero stator frequency operating point adaptive speed sensorless full-order observers Stability in control theory full-order Luenberger flux observer stability analysis stabilising methods MIMO systems sensorless machine control induction machines augmented error signal Asynchronous machines stators Routh-Hurwitz criterion Routh methods single-input single-output system rotor flux-oriented vector control observers sensorless vector-controlled drives Simulation, modelling and identification rotors stator resistance estimation

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