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Most of the industrial applications are multiple-input multiple-output (MIMO) systems, that can be be identified using knowledge of the system's physics or from measured data employing statistical methods. Currently, there is the only class of statistical identification methods capable of handling the issue of vast MIMO systems - subspace identification methods. These methods, however, as all statistical...
We compare the LQR control for a long-but-finite string of 2 × 2 MIMO systems with the LQR control for the corresponding infinite-dimensional spatially invariant system. We provide analytical and numerical examples where these are different and we investigate the cause. We also provide sufficient conditions for the LQR solutions to be similar as the length of the string increases. This work extends...
This paper investigates a Slotted ALOHA protocol for a multi-user wireless system operating under partial Line of Sight (LOS) conditions in which both the base station and mobile users are equipped with multiple element antennas. The investigations focus on how physical layer parameters such as spatial correlation, mutual coupling and Rician factor K affect the system capacity. Probability model for...
Linear receivers are often used in multiple-antenna systems due to ease of implementation. However, traditional linear receivers such as the Decorrelator and the linear minimum-mean squared error (MMSE) receiver often have a significant performance loss compared to the optimal joint maximum likelihood (ML) receiver. In previous work, we proposed the Integer-Forcing linear receiver, which bridges the...
A ray-tracing model was used to investigate the spectral efficiency of multiple input, multiple output (MIMO) antenna array systems in a rectangular space representing a typical short-range indoor environment. Results are presented from simulations in which the positions of the individual array elements were adjusted to improve the system capacity. These adjustments were done iteratively based on...
When channel state information is available at the transmitter, it can be exploited to increase the throughput, or to enhance the performance of a multiple input multiple output (MIMO) system. Beamforming schemes, such as closed loop MIMO and transmit beamforming constitute efficient means to achieve the aforementioned objectives. A significant shortcoming of transmit beamforming schemes is the signaling...
Beamforming is one of the key techniques for the multiple-input multiple-output (MIMO) wireless communication systems, which enables the system to achieve higher performance. In this paper, the Grassmann codebooks are employed to quantize channel state information (CSI) in the MIMO downlink for Long Term Evolution (LTE). Further more, a novel beamforming (BF) scheme based on the proposed equivalent...
Multiple input-multiple output (MIMO) system is a promising technique for B3G/4G development. In this paper, the MIMO system above a 3-D randomly rough surface is modelled and numerically analyzed. The Monte Carlo method is employed to generate randomly rough surface, and the Kirchhoff approximation (KA) is applied to calculation of system scattering and the channel transfer matrix. It shows the dependence...
The objective of this paper is to compare the time specification performance among four state feedback tracking controller design methods and determine which control method delivers better performance for linear MIMO systems. The four controller design methods are Pole Placement method, Linear Quadratic Regulator (LQR), an Eigenvalue Assignment method for shaping the output response and a method based...
To solve the shortcomings of traditional PID controller in dealing with disturbance rejection and robustness and the over-reliance on mathematical model of the controlled system, a model-free adaptive control algorithm based on linearization of partial format is proposed for discrete-time MIMO nonlinear systems. In this algorithm, nonlinear system is linearized by linearization of partial format method...
This paper presents a modified particle swarm optimization (MPSO) algorithm to design an optimal multi input multi out (MIMO) fuzzy logic controller for a cement mill process. The membership function, rule base and the scaling factor of the multi input multi output FLC is tuned for optimal control performance using MPSO by minimizing the Integral absolute error for minimum and maximum operating setpoints...
This paper proposes an MMSE detector applying the reciprocal lattice reduction (LR) in MIMO systems. The proposed detector achieves as good as or better BER performances than the LR aided detector using the conventional LLL algorithm and using the Seysen's algorithm in the 4×4 and the 8×8 MIMO systems. It also achieves BER curves to be as steep as or steeper than those using the maximum likelihood...
The optimal disturbance Suppressing problem for MIMO systems affected by external sinusoidal disturbances based on stability degree constraint is presented in this paper. The purpose is to find an LQR optimal controller, by which the cost function minimum and the state with the optimal having a higher mean-square convergence rate can be obtained. A LQR control law is derive from a Riccati equation...
The fixed-complexity sphere decoder (FSD) has been proposed to attain the near-optimal performance achieving the same diversity order as the maximum-likelihood decoder (MLD). However, it suffers great redundant computations resulting in very high power consumption. In this paper, we combine the probabilistic tree pruning (PTP) method proposed recently by Shim and Kang with the original FSD. This algorithm...
Antenna layout can affect the ergodic capacity of Multiple Input Multiple Output (MIMO) system. In this paper, we use simulated annealing (SA) to search for the optimal antenna layout with diameter constraint under the uniformly scattering fading environments. The results show that the optimal layout is close to uniform circular array only when the diameter is smaller than the half of wavelength.
In recently years, lattice-reduction (LR) has been proposed to improve the performance of linear and successive interference cancellation (SIC) detectors in MIMO systems. It is proved that LR-aided linear detectors collect the same diversity order as that exploited by the ML detector but with much lower complexity when perfect channel state information (CSI) is available at receiver side. However,...
In this paper, two decoders with low decoding complexity for a MIMO system with finite bit feedback channel are proposed. Theoretical analysis on performance and simulations show that the loses of performance comparing to the ML-decoder are acceptable.
In this paper, we take advantage of the RobustICA which is the new achievement of Blind source separation. Committed to apply this method to MIMO communication system, approve the capacity of MIMO system by reducing the number of training sequence and the steps of channel estimation. The methods of this paper are all Semi-Blind, compared to the traditional method, new Semi-Blind scheme have advantage...
Sphere decoding (SD) algorithms for MIMO receivers can achieve similar performance to maximum-likelihood detection (MLD) algorithm with lower computational complexity. In general, channel decoding methods can achieve better performance if they are combined with soft-output SD rather than hard-output one. Unfortunately, not all soft-output values can be obtained in SD. Although several constants could...
Lattice reduction is an effective technique for improving the performance of MIMO data detection. In this paper, we analyze lattice reduction processing on the basis lattice and the dual lattice for MIMO detection and investigate the parameters which affect the complexity of the LLL algorithm. Through use of the dual lattice in the LLL algorithm, the BER performances are improved about 2.2dB at BER=10...
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