Output feedback stabilisation of single-input single-output linear systems with I/O network-induced delays. An eigenvalue-based approach

The demand for ubiquitous telecommunications services forces operators to have a special concern about signal quality and the coverage area they offer to their customers. This was usually checked by using suitable propagation models for Single Input Single Output (SISO) systems, which are no longer the case for new and future mobile generations, such as 5G and beyond. To guarantee good signal quality coverage, operators started to replace these models with Multiple Input Multiple Output (MIMO) ones. To achieve the best results, these models are usually calibrated with Drive Test (DT) measures; however, the DTs available for MIMO propagation models are sparse, in contrast to SISO ones. The main contribution presented in this paper is a methodology to extend the propagation models of SISO systems so they can be applied in MIMO sytems with Single-Carrier and Frequency-Domain Equalization (SC-FDE), while still using DTs acquired for SISO systems. This paper presents the impact on Bit Error Rate (BER) performance and its coverage area resulting from the application of our proposed method. We consider a MIMO SC-FDE system with an Iterative Block Decision Feedback Equalization (IB-DFE) receiver and we present the improvement expressions for the BER that we illustrate with some simulations.

The design of a multi-level fuzzy-logic control system for the control of turbine engines using type-1 fuzzy-logic is presented in this paper. A Matlab-Simulink model of an advanced turbine engine was used to test and validate the performance of the developed fuzzy control system. The model provided comprehensive and complex model of a turbine engine. As with most modeling of turbine engines, it was assumed that the fundamental dynamic characteristics of a turbine engine can be achieved by control of the engine fuel flow. In this model a single input single output (SISO) system is used to control the engine fuel flow, where the input to the SISO system is the low spool speed error signal and the output is the fuel flow actuator control signal. A fuzzy controller was developed for the SISO system and its performance is compared with that of the existing proportional integral (PI) controller. Both controllers were tested under normal operating conditions and with introduction of engine faults embedded in the model.

Given a SISO (single-input single-output) system with arbitrary poles and zeros in the closed right half plane and having time delay uncertainty, the question arises as to the maximum time delay margin available before the closed-loop system becomes unstable when an arbitrary controller is connected to the SISO system in the closed loop. The authors provide a solution to this problem and show how to derive the controller corresponding to the optimum condition. The method of solution is based on general framework of P.P. Khargonekar and R. Tannenbaum (1985) for the robust stabilization of SISO systems with parameter uncertainty using Nevanlinna-Pick interpolation theory and the theory of conformal mapping. >

Some Remarks on Output Feedback Stabilization of SISO Systems with I/O Network-Induced Delays

This paper proposes a model predictive controller for multivariable systems with time-delays. The design method is derived by the following way, first to consider a design for single input single output(SISO) systems and to modify the control problem for the SISO systems with no time-delays by shifting the outputs with time-delay steps and a design method with no time-delays is applied to the modified systems. Then the SISO case is extended to multi-input multi-output(MIMO) case by replacing time-delay steps in SISO case with an interactor matrix of MIMO plants.

We have developed a loop-shaping methodology for robust control design in single-input single-output (SISO) systems with structured and unstructured uncertainties. This design method employs visualization tools that are modifications of the classical Bode plot. Using the proposed method control engineers can easily consider the effects of the structured and unstructured uncertainties without the need for transfer-function models of the plant, the sensitivity function performance, or the uncertainty. The method simultaneously can avoid excessive conservativeness and excessively high order controllers while improving controller performance and robustness. We show utility of the proposed method by applying it to a head-positioning control system in a hard disk drive.

The channel capacity of multiple-input multiple-output (MIMO) wideband CDMA system with coherent RAKE receiver is considered. General multi-path intensity Nakagami fading and multiple-access near/far interference channel are assumed. The analysis for system performance shows that the error of channel estimation significantly degrades BER performance and can be effectively suppressed by RAKE receiver and MIMO schemes. Also, an attempt for comparing the channel capacity on different performance improvement schemes has been made. In particular, the channel capacity of MIMO system is compared with single-input single-output (SISO) system. The MIMO complex spreading CDMA system with path correlation yields better performance with respect to channel capacity than a SISO system with i.i.d. input and output. And a discussion on the multiple-access near/far interference is also included, which illustrates that it can be effectively limited by power control and channel estimation schemes.KeywordsChannel EstimationChannel CapacityPilot SymbolInterference ModelCDMA SystemThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

In this paper, we derive the analytical expressions for the secure outage probability in a single-input single-output (SISO) system over fading, in which both the main and eavesdropper channels are subject to κ-μ fading. Many authors have analyzed the secrecy performance of such a SISO system over various fading models. More recently, a lower bound on the secure outage probability over κ-μ fading has been reported. However, the exact analytical expression of secure outage probability over κ-μ fading has not been obtained. The problem with using the lower bound is that we are not sure about the tightness of the bound. Our result is an exact expression which is verified by Monte-Carlo simulations. Furthermore, it enables us to examine the behavior of the secure outage probability as a function of the fading parameters of both the main and eavesdropper channels for given values of the average signal-to-noise power ratio (SNR) over these channels. Exact expressions for the case of Nakagami-m and Rician fading models for both the main and eavesdropper channels are also obtained and verified by simulations.

Model reduction of SISO systems by Routh expansion and balancing method

This note deals with the delay-dependent stability and stabilization of linear system with state and input delays. Firstly, for the nominal system, by introducing the augmented Lyapunov functional and some free-weighting matrices, new delay-dependent stability and stabilization criteria of the system are presented. Then, these new conditions are extended to handle norm-bounded uncertain systems with state and input delays, which show less conservativeness. Numerical examples are given to illustrate the effectiveness of the proposed results.

The Nyquist stability criterion and the notion of type n systems have been extended from lumped parameter systems to a larger class of linear single-loop single-input single-output time-invariant systems, with constraints presented in the text.

In this paper, the problem of designing a tracking controller for uncertain nonlinear second-order SISO (single input single output) systems which can suppress the effects of both the model uncertainty and noisy measurements is considered. Based on the framework of linear systems with nonlinear uncertainties whose norm-bounds are known we construct not only a sliding mode controller but a sliding observer for uncertain nonlinear second-order SISO systems, and we show the robust stability of the closed-loop control system. >

Optimal performance of discrete-time control systems based on network-induced delay

This paper addresses the problem of identifying the graph structure of a dynamical network using measured input/output data. This problem is known as topology identification and has received considerable attention in recent literature. Most existing literature focuses on topology identification for networks with node dynamics modeled by single integrators or single-input single-output (SISO) systems. The goal of the current paper is to identify the topology of a more general class of heterogeneous networks, in which the dynamics of the nodes are modeled by general (possibly distinct) linear systems. Our two main contributions are the following. First, we establish conditions for topological identifiability, i.e., conditions under which the network topology can be uniquely reconstructed from measured data. We also specialize our results to homogeneous networks of SISO systems and we will see that such networks have quite particular identifiability properties. Secondly, we develop a topology identification method that reconstructs the network topology from input/output data. The solution of a generalized Sylvester equation will play an important role in our identification scheme.

Mission critical narrow-band wireless communications standards such as IEEE 802.15.4g Smart Utility Network (SUN), Project 25, TETRA, ZigBee and custom SCADA systems were defined as Single Input Single Output (SISO) systems. As a result they lack built in provisions for smart multiport transceivers and associated antennas. These and other standards often lack channel coding techniques and may implement non-coherent modulation. Yet these systems are increasingly overwhelmed by interference in the form of network congestion, secondary users and out of band induced receiver intermodulation products. These networks operate in highly scattered environments that include multipath fading and Polarization Dependent Loss (PDL). This paper reviews multi-polarized antenna arrays and algorithms that exploit polarization scattering in the channel to mitigate both PDL and interference. These antennas and algorithms can be overlaid in new and replacement equipment providing Dynamic Spectrum Access (DSA) and an average 23dB Signal to Interference plus Noise Ratio (SINR) link budget improvement for mission critical SISO communication standards.