We propose an adaptive beamforming scheme for the combination of orthogonal frequency division multiplexing (OFDM) and adaptive antenna array. The combinational scheme is characterized by the sample matrix inverse (SMI) algorithm, frequency-to-time pilot transform and pre-FFT combination. For every OFDM block containing both data and pilot symbols, we transform the frequency-domain pilot symbols to the corresponding time-domain components. One of the obvious advantages of this transform is that the time interval of the antenna weight vector update can be reduced to only one OFDM sample interval, from one OFDM block interval of the conventional beamforming scheme in which the transform is not applied. This feature can greatly accelerate the convergence of SMI beamforming. The simulation results verify that the proposed beamforming scheme is capable of improving the convergence behavior significantly.

In this paper, we propose a new robust model predictive control (MPC) technique for linear parameter varying (LPV) systems expressed as linear systems with feedback parameters. It is based on the minimization of the upper bound of finite horizon cost function using a new parameter dependent terminal weighting matrix. The proposed parameter dependent terminal weighting matrix for norm-bounded uncertain models provides a less conservative condition for terminal inequality. The optimization problem that satisfies the terminal inequality is solved by semi-definite programming involving linear matrix inequalities (LMIs). A numerical example is included to illustrate the effectiveness of the proposed method.

Point pattern matching (PPM) arises in areas such as pattern recognition, digital video processing and computer vision. In this study, a novel Genetic Algorithm (GA) based method for matching affine-related point sets is described. Most common techniques for solving the PPM problem, consist in determining the correspondence between points localized spatially within two sets and then find the proper transformation parameters, using a set of equations. In this paper, we use this fact that the correspondence and transformation matrices are two unitary polar factors of Grammian matrices. We estimate one of these factors by the GA's population and then evaluate this estimation by computing an error function using another factor. This approach is an easily implemented one and because of using the GA in it, its computational complexity is lower than other known methods. Simulation results on synthetic and real point patterns with varying amount of noise, confirm that the algorithm is very effective.

The authors propose a single-layer hollow-waveguide 8-way Butler matrix. All components of the Butler matrix are in a single layer which contributes to low-cost fabrication. To reduce the length of the couplers, a step structure is installed in the coupled region. 50% length reduction is obtained in comparison with the conventional design using reflection-suppressing posts in the coupled region. The total size of the matrix is 17.1λg6.0λg. The full structure of the matrix is fabricated by hollow waveguides at 22 GHz band and the total measured loss is only 0.25 dB.

A simple method for the gain improvement of matrix distributed amplifiers is presented. The method is based on modifying the central transmission line of the matrix amplifier without any changes in the input and output transmission lines. In the new method the termination impedances in the central transmission line are modified and the transmission line is replaced by an impedance matching circuitry. It has been shown that the new method can significantly improve the gain while preserving the input and output return losses of the amplifier.

A new control scheme is proposed to improve the system performance for discrete-time fuzzy systems by tuning control grade functions using neural networks. According to a systematic method of constructing the exact Takagi-Sugeno (T-S) fuzzy model, the system uncertainty is considered to affect the membership functions. Then, the grade functions, resulting from the membership functions of the control rules, are tuned by a back-propagation network. On the other hand, the feedback gains of the control rules are determined by solving a set of LMIs which satisfy sufficient conditions of the closed-loop stability. As a result, both stability guarantee and better performance are concluded. The scheme applied to a truck-trailer system is verified by satisfactory simulation results.

The authors have proposed a 1 m2 single-layer slotted waveguide array consisting of conducting baffles and quartz glass strips positioned in front of the slot aperture, which is referred to as a vacuum window, for microwave plasma excitation. The effect of the complicated outer vacuum window hinders the realization of uniform distribution. In this paper, a unit-cell of the alternating-phase fed single-layer slotted waveguide array with the vacuum window is analyzed by generalized scattering matrix method (GSM)-method of moments (MoM) hybridization analysis, and the array is designed to realize uniform aperture electromagnetic field distribution, where the plasma and the chamber is neglected. The GSM-MoM analysis gives reliable numerical results while the MoM has numerical errors due to singularities of Green's function for a long cavity. Uniform aperture EM field distribution outside of the vacuum window is observed in near field measurements using a 1/5 scale model antenna, and the validity of the analysis and design is verified.

We propose transformation of a parity-check matrix of any low-density parity-check code. A code with transformed parity-check matrix is an equivalent of a code with the original parity-check matrix. For the binary erasure channel, performance of a message-passing algorithm with a transformed parity-check matrix is better than that with the original matrix.

The average performance of a single-user MIMO system under spatially correlated fading and with different types of CSI at the transmitter and with perfect CSI at the receiver was studied in recent work. In contrast to analyzing a single performance metric, e.g. the average mutual information or the average bit error rate, we study an arbitrary representative of the class of matrix-monotone functions. Since the average mutual information as well as the average normalized MSE belong to that class, this universal class of performance functions brings together the information theoretic and signal processing performance metric. We use Lowner's representation of operator monotone functions in order to derive the optimum transmission strategies as well as to characterize the impact of correlation on the average performance. Many recent results derived for average mutual information generalize to arbitrary matrix-monotone performance functions, e.g. the optimal transmit strategy without CSI at the transmitter is equal power allocation. The average performance without CSI is a Schur-concave function with respect to transmit and receive correlation. In addition to this, we derive the optimal transmission strategy with long-term statistics knowledge at the transmitter and propose an efficient iterative algorithm. The beamforming-range is the SNR range in which only one data stream spatially multiplexed achieves the maximum average performance. This range is important since it has a simple receiver structure and well known channel coding. We entirely characterize the beamforming-range. Finally, we derive the generalized water-filling transmit strategy for perfect CSI and characterize its properties under channel correlation.

This paper proposes a robust fuzzy integral controller for output regulating a class of affine nonlinear systems subject to a bias reference to the origin. First, a common biased fuzzy model is introduced for a class of continuous/discrete-time affine nonlinear systems, such as dc-dc converters, robotic systems. Then, combining an integrator and parallel distributed compensators, the fuzzy integral regulator achieves an asymptotic regulation. Moreover, when considering disturbances or unstructured certainties, a virtual reference model is presented and provides a robust gain design via LMI techniques. In this case, H∞ performances is guaranteed. Note that the information regarding the operational point and bias terms are not required during the controller implementation. Thus, the controller can be applied to a multi-task regulation. Finally, three numerical simulations show the expected results.

This letter presents robustness bounds (RBs) for receding horizon controls (RHCs) of uncertain systems. The proposed RBs are obtained easily by solving convex problems represented by linear matrix inequalities (LMIs). We show, by numerical examples, that the RHCs can guarantee robust stabilization for a larger class of uncertain systems than conventional linear quadratic regulators (LQRs).

The Navigational Programming (NavP) methodology is based on the principle of self-migrating computations. It is a truly incremental methodology for developing parallel programs: each step represents a functioning program, and each intermediate program is an improvement over its predecessor. The transformations are mechanical and straightforward to apply. We illustrate our methodology in the context of matrix multiplication, showing how the transformations lead from a sequential program to a fully parallel program. The NavP methodology is conducive to new ways of thinking that lead to ease of programming and high performance. Even though our parallel algorithm was derived using a sequence of mechanical transformations, it displays certain performance advantages over the classical handcrafted Gentleman's Algorithm.

An efficient pad assignment methodology to minimize voltage drop on a power distribution network is proposed. A combination of successive pad assignment (SPA) with incremental matrix inversion (IMI) determines both location and number of power supply pads to satisfy drop voltage constraint. The SPA creates an equivalent resistance matrix which preserves both pad candidates and power consumption points as external ports so that topological modification due to connection or disconnection between voltage sources and candidate pads is consistently represented. By reusing sub-matrices of the equivalent matrix, the SPA greedily searches the next pad location that minimizes the worst drop voltage. Each time a candidate pad is added, the IMI reduces computational complexity significantly. Experimental results including a 400 pad problem show that the proposed procedures efficiently enumerate pad order in a practical time.

An order selection scheme for two-sided oblique projection-based interconnect reduction will be investigated. It will provide a guideline for terminating the conventional nonsymmetric Pade via Lanczos (PVL) iteration process. By exploring the relationship of the system Grammians of the original network and those of the reduced network, it can be shown that the system matrix of the reduced-order system generated by the two-sided oblique projection can also be expressed as those of the original interconnect model with some additive perturbations. The perturbation matrix only involves bi-orthogonal vectors at the previous step of the nonsymmetric Lanczos algorithm. This perturbation matrix will provide the stopping criteria in the order selection scheme and achieve the desired accuracy of the approximate transfer function.

The RGB signals generated by different cameras are not equal for the same scene. Therefore, cameras are characterized based on a CIE standard colorimetric observer. One method of deriving a colorimetric characterization matrix between camera RGB output signals and CIE XYZ tristimulus values is least squares polynomial modeling. Yet, this involves tedious experiments to obtain a camera transfer matrix under various white balance points for the same camera. Accordingly, the current paper proposes a new method for obtaining camera transfer matrices under different white balances using a 33 camera transfer matrix under a specific white balance point.

Normal and dual bases are two popular representation bases for elements in GF(2m). In general, each distinct representation basis has its associated different hardware architecture. In this paper, we will present a unified systolic array multiplication architecture for both normal and dual bases, such a unified multiplication architecture is termed a Hankel multiplier. The Hankel multiplier has lower space complexity while compared with other existing normal basis multipliers and dual basis multipliers.

This paper makes an examination of BER (bit error rate) performance in 22 MIMO (Multi-Input Multi-Output) systems using spatial multiplexing in a LOS (line-of-sight) environment by analysis using the eigenvalue and eigenvector of the channel matrix and simulation. It is shown that BER performance in a LOS environment is dependent on the phase relation of direct paths and the minimum squared absolute value of the eigenvalue, which are determined by the propagated distance. A technique for improving BER performance in a LOS environment is then considered based on these findings. A receive antenna selection (RAS) technique is presented which uses the minimum squared absolute value of the channel matrix eigenvalue. Proof is then given that BER performance is improved using this RAS technique, thus making clear the validity of this approach for obtaining optimum BER performance in a LOS environment.

We propose a DOA-Matrix based blind CFO estimation method for a MIMO-OFDM system with Virtual Carriers. The method estimates CFO in closed-form by jointly exploiting the shift-invariant structure of time-domain signal received on multiple receive antennas. In contrast to previous training-based methods, the proposed method is bandwidth efficiency. We also present numerical simulation results for different transmit and receive antenna configurations and for different record lengths.

Millimeter-wave (MMW) communication systems, specially from 60 GHz band, are expected to play a key role in realizing the intelligent transportation system (ITS) for high date rate and mulitmedia communications. During the last years, System-in-package (SiP) solutions for MMW RF-transceiver have become an attractive alternative to System-on-Chip (SoC) approaches. In the scheme, active circuits are integrated with passive circuit much tightly. Traditional distributed hybrid circuit concept, such as ADS and Microwave Office, is not quite applicable for SiP, specially in MMW frequency. In this paper, an improved finite-difference time-domain formulation using the matrix theory and an improved integral transform is presented to solve hybrid high-order linear lumped circuit and passive circuit problem implicitly instead of explicit method used for traditional FDTD method. In this improved method, general high-order linear lumped circuit is expressed firstly as not only one equation but also equations set according kirchhoff's laws. Then, a local iterative matrix expression connecting with each active circuit can be built when EM fields, current/current density and interior variable of equations set are treated as separated vector element. In order to make this formulation stable, an improved integral transform is proposed to reform the matrix's condition number. Simulations show that the results by our improved FDTD formulation can effectively not only keep the accuracy of passive circuit, but also integrate high-order linear lumped circuit expressed by equations set as well as one equation.

The power line communication (PLC) system should be investigated with respect to the influence on electromagnetic environments. Longitudinal conversion loss (LCL) and input impedance are important parameters for evaluating the influence because they are closely related to the radiated, conducted, and inducted emission. An indoor AC mains system consisting of electrical equipment and an AC mains line was modeled by four-port networks, and the LCL and the input impedance were calculated. The parameters of the four-port networks were determined from theory and measurement. The analytical model was examined using a simple network and the results show that the calculated values agreed with the measured ones. The LCL and the input impedance were investigated at the AC mains port in some existing buildings, and the measured results almost agreed with the calculated results derived from the indoor AC mains system model.