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Showing papers on "MIMO published in 1993"


Journal ArticleDOI
TL;DR: This paper reformulate the identification of linear time-invariant systems operating in a closed-loop with an LTI compensator to an open-loop multi-input-multi-output (MIMO) (state space model) identification problem, followed by a model reduction step.

168 citations


Proceedings ArticleDOI
18 May 1993
TL;DR: Some distributed channel schemes for a one-dimensional cellular radio system are described and the channel assignment in the schemes proposed is based on signal strength measurements and therefore gives an improvement in capacity over schemes using reuse distance criterion for channel assignment.
Abstract: Some distributed channel schemes for a one-dimensional cellular radio system are described. The channel assignment in the schemes proposed is based on signal strength measurements and therefore gives an improvement in capacity over schemes using reuse distance criterion for channel assignment. The proposed schemes are evaluated by simulations and their behavior with variation in traffic density, size of the channel set and number of reassignments is studied.

83 citations


Book
28 May 1993
TL;DR: In this paper, a Markov Parameter approach is used for robust control of the SISO case and robust control for the glass tube process. But this approach is not suitable for the case of continuous-time models.
Abstract: Linear Models of Dynamic Processes and Signals.-Identification Experiment and Data Pre-Treatment.-Identification by the Least Squares Method.- Extensions of the Least-Squares Method.- MIMO Process Identification: A Markov Parameter Approach.- Identification for Robust Control SISO Case.- Identification for Robust Control MIMO Case.-Identification and Robust Control of the Glass Tube Process.-Identification for Fault Diagnosis Estimation of Continuous-Time Models.

57 citations


Proceedings ArticleDOI
Bouchra Senadji1
01 Nov 1993
TL;DR: The paper addresses the definition of validation criteria in order to evaluate and quantify the accuracy of each proposed model and describes the properties and limitations of the present methods used for channel modeling.
Abstract: This paper addresses the problem of mobile radio propagation channel modeling and underlines the need for further research in this domain. The paper first describes three characteristics of the mobile radio propagation channel which are the propagation-path loss, the time-varying aspect, and the multipath characteristics. It then describes the properties and limitations of the present methods used for channel modeling. The main limitation concerns the non-stationary aspect of the mobile radio propagation channel. Two signal processing approaches are proposed to remedy the problem. Finally, the paper addresses the definition of validation criteria in order to evaluate and quantify the accuracy of each proposed model.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

37 citations


Journal ArticleDOI
TL;DR: In this article, the benefits of passive damping in single-input single-output and multi-input multi-output (MIMO) feedback controlled structures were investigated, and theoretical formulations were derived verifying improved stability robustness characteristics for simple controlled structures.
Abstract: This paper investigates the benefits of passive damping in single-input single-output (SISO) and multi-input multi-output (MIMO) feedback controlled structures. Theoretical formulations are derived verifying improved stability robustness characteristics for simple controlled structures on phase margin, gain margin, and root locus properties of a SISO system. Control design techniques for closed-loop band widths beyond the first modal frequency require accurate knowledge of the structural dynamics, particularly at crossover. The use of passive damping in the structural design allows for a greater margin of error in pole-zero cancellation at crossover, thus improving the stability robustness. Minimum levels of required passive damping are derived for robust control of uncertain structures. The derivations are extended to suggest application to MIMO systems. Robustness improvements are quantified in case studies for an 8th-order SISO example and an 18th-order MIMO example and compared to the simple derivations.

25 citations


Journal ArticleDOI
TL;DR: A prototype adaptive automatic control algorithm was implemented to regulate temperatures measured at several points in a tumour by adjusting the power applied to several ultrasound transducers.
Abstract: A prototype adaptive automatic control algorithm was implemented to regulate temperatures measured at several points in a tumour by adjusting the power applied to several ultrasound transducers. The goal was to control the temperatures under the elements of a mosaic applicator individually without any a priori knowledge of which probes are under which elements. The control algorithm was devised for clinical applications where the position of each probe with respect to the heat sources is difficult to determine precisely. Instead, the program 'learns' the relationship between the inputs (power levels) and the outputs (temperatures) automatically. Based on the observed transfer function relating the power at m sources to the temperatures n probes, where n and m are not necessarily the same, a new method was used to implement a feedback controller. This method simplifies the design of the controller for a multiple-input/ multiple-output (MIMO) system, while taking into account the coupling that may exist bet...

21 citations


Journal ArticleDOI
TL;DR: In this article, the necessary and sufficient condition on the system under which there exists a control that can force the system to exhibit a requested tracking property without using any information about the mathematical description of the system internal dynamics and external disturbances.
Abstract: The key problems addressed and solved in the framework of time-invariant continuous-time multiple-input multiple-output (MIMO) linear systems are the following: (a) the necessary and sufficient condition on the system under which there exists a control that can force the system to exhibit a requested tracking property without using any information about the mathematical description of the system internal dynamics and external disturbances; (b) the synthesis of an output error algorithm expressing stablewise tracking with finite (pre-specified) reachability time; (c) the synthesis of a Proportional-Derivative (PD) control algorithm for stablewise tracking with finite (given) reachability time without utilizing a mathematical model of the system internal dynamics, its state and the unmeasured, unknown time-varying disturbances. Simulation results illustrate the theory with an unstable MIMO system under different desired stablewise tracking settling times.

17 citations



Journal ArticleDOI
TL;DR: An identification approach to three-phase power system modeling and model reduction taking the power system network network as multi-input, multi-output (MIMO) process is presented in this article.
Abstract: An identification approach to three-phase power system modeling and model reduction taking the power system network as multi-input, multi-output (MIMO) process is presented. The model estimate can be obtained in discrete-time input-output form, discrete- or continuous-time state-space variable form, or frequency-domain impedance transfer function matrix form. An algorithm for determining the model structures of this MIMO process is described. The effect of measurement noise on the approach is also discussed. This approach has been applied to a sample system. Simulation results are presented. >

14 citations


Journal ArticleDOI
L. Mo1, M.M. Bayoumi1
TL;DR: An adaptive pole-assignment controller design for an MIMO (multi-input-multi-output) system is with unknown observability indexes or with an overparameterized system model is presented and the controller design algorithm and stability issues are addressed.
Abstract: An adaptive pole-assignment controller design for an MIMO (multi-input-multi-output) system is with unknown observability indexes or with an overparameterized system model is presented. The controller design algorithm and stability issues are addressed. >

10 citations


Book ChapterDOI
01 Jan 1993
TL;DR: This paper presents a consistent solution to the ordering of characteristic patterns and of vectors, solely in the time domain of k-time sequences, which enables a unique input-output CPA-CPV decomposition.
Abstract: Due to theoretical results for convolution feedback systems in formed spaces of classes of signals, the time-domain input-output approach to MIMO control problem using matrices of weighting functions as basic system models has given rise to the computer-aided methodology of characteristic patterns and vectors, and its modification in terms of k-time sequence-matrices implement the idea of finding natural multivariable input-output modes. This paper presents a consistent solution to the ordering of characteristic patterns and of vectors, solely in the time domain of k-time sequences, which enables a unique input-output CPA-CPV decomposition. It is based on the analysis of weighted power distribution on path-subsystems in order to determine the dominant ones, which should appear in the main diagonal.

01 Jan 1993
TL;DR: In this article, the authors derived the asymptotic mutual information (MI) of a spatially correlated Rician multiple-input multiple-output (MIMO) multiple-access (MA) channel for any given signaling input distributions (not necessarily Gaussian) in the large-system regime where the numbers of antennas at the transmitters and the receiver go to infinity with a constant ratio.
Abstract: Using the replica method, originally developed in statistical physics, we derive the asymptotic mutual information (MI) of a spatially correlated Rician multiple-input multiple-output (MIMO) multiple-access (MA) channel for any given signaling input distributions (not necessarily Gaussian) in the large-system regime where the numbers of antennas at the transmitters and the receiver go to infinity with a constant ratio. In addition to the result that uses joint optimum decoding (JOD) at the central receiver, we also obtain asymptotic characteristics of a more practical system which performs separate detection and decoding (SDD) (i.e., spatial detection followed by a temporal error-correction decoder). Simulation results reveal that the asymptotic results provide promising estimates for the average performance metrics (e.g., the error probability and the MI) even with only a few antenna elements at the transceivers. © 1993 IEEE

Journal ArticleDOI
TL;DR: In this article, the Routh frequency-domain reduction (approximation) method, coupled with powerful dominant pole-selection criteria, is introduced for the purpose of application to high-degree transfer functions of MIMO linear time-invariant systems to obtain corresponding adequate reduced-order models.
Abstract: The Routh frequency-domain reduction (approximation) method, coupled with powerful dominant pole-selection criteria, is introduced for the purpose of application to high-degree transfer functions of multiple-input multiple-output (MIMO) linear time-invariant systems to obtain corresponding adequate reduced-order models. The proposed method has been applied successfully to a 10th-order matrix transfer function of a two-input two-output time-invariant linear model of a practical power system.

Journal ArticleDOI
TL;DR: In this paper, the authors try to control a linear MIMO process with time delay using the policy-and experience-driven neural network (PENN) method using the Policy-and Experience-Driven Neural Network (PENG) method.
Abstract: We try to control a linear MIMO process with time delay using the Policy- and Experience-Driven Neural Network (PENN) method


Journal ArticleDOI
TL;DR: An alternate graphical representation of linear, time-invariant, multi-input,Multi-output (MIMO) system dynamics is proposed that is highly suited for exploring the influence of closed-loop system parameters.
Abstract: An alternate graphical representation of linear, time-invariant, multi-input, multi-output (MIMO) system dynamics is proposed that is highly suited for exploring the influence of closed-loop system parameters. The development is based on the adjustment of a scalar forward gain multiplying a cascaded multivariable controller/plant embedded in an output feedback configuration. By tracking the closed-loop eigenvalues as explicit functions of gain, it is possible to visualize the multivariable root loci in a set of «gain plots» consisting of two graphs: (i) magnitude of system eigenvalues versus gain and (ii) argument (angle) of system eigenvalues versus gain

Journal ArticleDOI
TL;DR: In this article, a PC based real-time simulator of the dynamic behaviour of non-linear MIMO (Multiple Input, Multiple Output) systems is presented, where the strategy is developed in the time domain.

Journal ArticleDOI
TL;DR: Although the model is time varying, keeping the error feedback coefficients fixed results in almost equal reduction as with time-varying coefficients, so the roundoff noise can be cut down very efficiently with only 8% increase in program execution time.

Proceedings ArticleDOI
19 May 1993
TL;DR: The authors describe and analyze a model for the Gaussian multiple access channel, where the addition of new users is governed by a renewal process, and finds the set of transmission rates at which the reliable communication of the messages of each user is possible.
Abstract: The authors describe and analyze a model for the Gaussian multiple access channel, where the addition of new users is governed by a renewal process. An information-theoretic approach is used to find the set of transmission rates at which the reliable communication of the messages of each user is possible. The capacity for the Markovian multiple access channel is shown to be dependent on the utilization factor of the system. >

Journal ArticleDOI
TL;DR: In this article, a proportional plus integral matrix control structure for MIMO systems is proposed, which permits a greater degree of independence of the design and tuning of the regulating and tracking features, without considerably increasing the controller complexity.
Abstract: A proportional plus integral matrix control structure for MIMO systems is proposed. Based on a standard optimal control structure with integral action, it permits a greater degree of independence of the design and tuning of the regulating and tracking features, without considerably increasing the controller complexity. Fast recovery from load disturbances is achieved, while large overshoots associated with set-point changes and reset wind-up problems can be reduced. A simple effective procedure for practical tuning is introduced.


Journal ArticleDOI
TL;DR: In this paper, an adaptive controller developed from a generalized cost function is studied for a MIMO system with a binary distillation column and theoretical derivation is considered first.
Abstract: An adaptive controller developed from a generalized cost function is studied in this work. Theoretical derivation is considered first. Application of such controller to a multiple-input multiple-output (MIMO) system—a binary distillation column is examined. Practical issues in the implementation of adaptive regulators to control chemical engineering processes are discussed in detail.

Proceedings ArticleDOI
31 Oct 1993
TL;DR: In this article, a multiple input multiple output (MIMO) identification approach combining both reflection and transmission data from experiments performed on a linear viscoelastic material at normal incidence is presented.
Abstract: This paper presents a multiple input multiple output (MIMO) identification approach, combining both reflection and transmission data from experiments performed on a linear viscoelastic material at normal incidence The parametric modeling of the wave propagation, the calibration of the measurement setup and the estimation of the model parameters are elaborated The broadband absorption-dispersion functions are incorporated in the wave propagation model by means of a rational transfer function It is shown that the redundancy in the MIMO identification approach (both reflection and transmission) leads to an improved estimate of the material properties with respect to reflection or transmission identification only

Proceedings ArticleDOI
02 Jun 1993
TL;DR: This paper presents the up-dating of Version 1 of the MIMO/QFT CAD package to handle the design of discrete in addition to analog robust control systems for MIMo uncertain plants.
Abstract: This paper presents the up-dating of Version 1 of the MIMO/QFT CAD package to handle the design of discrete in addition to analog robust control systems for MIMO uncertain plants. Version 2 of the CAD package is capable of carying an analog or discrete design problem from problem setup through the design process to a frequency domain analysis of the compensated MIMO system. For analog control problems, the design process is performed in the s-plane, while for the discrete control problems the plants discretized and the design process is performed in the w'-plane. The package automates the selection of the weighting matrix; descretization of the plants; formation of the square effective plants; the polynomial matrix inverse required to form the equivalent plants; generation of templates; selecion of a nominal plant; generation of stablity, tracking, disturbance, gamma, and composite bounds; loop shaping; design of the prefilter elements; frequency-domain analysis of the completed design; and the export of the completed design to MATRIXx or MATLAB for time-domain simulation. Disturbance allocation is automatically performed while generating the tracking bounds. The package allows gain scheduling to be used in the weighting matrix. The improved method may be applied for the general case of an m×m effective plant. The package is implemented usig Mathematica for use on the Sun Workstations.

Proceedings ArticleDOI
13 Sep 1993
TL;DR: In this paper, the results presented by Robinson and Clarke (1991) are extended to the MlMO GPC/MRM method and it is shown how to apply them.
Abstract: This paper is concerned with multivariable generalized predictive control with multiple reference model in its polynomial form (MIMO GPC/MRM). The results presented by Robinson and Clarke (1991) are extended to the MlMO GPC/MRM method and it is shown how to apply them. Then the method is applied to a helicopter; simulation results are given which show the decoupling efficiency and the robustness of the controller by a test on a weakly mismatched system and the improvement of the robustness brought by the T matrix filter on a strongly mismatched system. >

Proceedings ArticleDOI
28 Mar 1993
TL;DR: The mathematical derivation of an adaptive observer based on integration of the two techniques is presented and the identification of unknown multiple input multiple output (MIMO) systems with noise corrupted measurements is described.
Abstract: Hopfield networks have been applied to the problem of system identification. Luenberger observers have long been used for estimation of unmeasurable states of linear systems. The mathematical derivation of an adaptive observer based on integration of the two techniques is presented. The identification of unknown multiple input multiple output (MIMO) systems with noise corrupted measurements is described. Simulation results for different plant conditions are detailed. >

Proceedings ArticleDOI
14 Sep 1993
TL;DR: This work aims to estimate the capacity, in the information-theoretic sense, of a selective-fading channel between N mobile units and a base station equipped with M diversity antennas.
Abstract: Third-generation mobile radio systems will ensure the provision of several remote services, thus creating signals of sufficient bandwidth to produce frequency-selective fades. In these conditions a sufficiently sophisticated receiver can exploit knowingly the multipath diversity of the channel. This work aims to estimate the capacity, in the information-theoretic sense, of a selective-fading channel between N mobile units and a base station equipped with M diversity antennas. Increased capacity in the presence of selective fading is especially noted. >

01 Sep 1993
TL;DR: The performance of the MIMO RLS algorithm is compared against another method of control, the steepest descent algorithm, where it seeks to produce an optimal transmitter drive waveform (TDW).
Abstract: : A multiple-input, multiple-output (MIMO) recursive least squares (RLS) algorithm is developed to shape and control the Loran-C RF pulse of the AN/FPN-44A tube type transmitter. The control algorithm is incorporated into a transmitter simulation program, where it seeks to produce an optimal transmitter drive waveform (TDW). An optimal TDW produces a near ideal RF pulse. The control algorithm uses a MIMO reference model of the transmitter; parameters of the model are obtained using recursive least squares multichannel time series techniques. The MIMO reference model has the ability to adapt to the non-LTI characteristics of the simulated transmitter. The MMO RLS control algorithm is implemented in both an ideal and a realistic noisy environment. In the ideal environment, when representing the RF pulse with parameters of its half-cycle peak amplitudes and zero-crossings, the MIMO RLS controller is able to shape the RF pulse and control its zero-crossings. Quantization and system noise in the non-ideal environment results in performance deterioration of the control algorithm. The performance of the MIMO RLS algorithm is compared against another method of control, the steepest descent algorithm.

Proceedings ArticleDOI
02 Jun 1993
TL;DR: An algorithm is developed to calculate the number of models required for the SISO and MIMO multi-rate systems, using the multiple model result, and a least squares identification procedure provides the required model parameters.
Abstract: Unlike parameterisations of single rate systems, we note that every multirate system cannot be parameterized using a single model. Using a lifting strategy, a parameterized set of models can be developed for SISO and MIMO systems. We develop an algorithm to calculate the number of models required for the SISO and MIMO multi-rate systems. Using the multiple model result, a least squares identification procedure provides the required model parameters.

Proceedings ArticleDOI
D.H. Chyung1
17 Oct 1993
TL;DR: A delayed feedforward tracking controller is derived for linear time invariant control systems and a necessary and sufficient condition for the existence of such a controller is given.
Abstract: A delayed feedforward tracking controller is derived for linear time invariant control systems. A necessary and sufficient condition for the existence of such a controller is also given. >