For multi-input multi-output (MIMO) through-wall radar imaging (TWRI), multipath ghosts and side/grating lobe artifacts degrade the imaging quality of the obscured targets inside an enclosed building, therein hinderin...
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For multi-input multi-output (MIMO) through-wall radar imaging (TWRI), multipath ghosts and side/grating lobe artifacts degrade the imaging quality of the obscured targets inside an enclosed building, therein hindering target detection. In this paper, an approach based on two stacked generative adversarial nets (GAN) is proposed to achieve multipath and side/grating lobe suppression with regard to MIMO TWRI. Specifically, the Stage-I GAN constructs a spatial structure mapping from the original input images to the Stage-I GAN output images with the suppressed multipath ghosts. However, the side/grating lobe artifacts are intentionally preserved in the stage-I GAN as additional constraint information to prevent uncontrollable over-fitting. Then, the Stage-II GAN takes the output images of Stage-I GAN as input to suppress the side/grating lobe artifacts. Extensive electromagnetic simulations and comparisons demonstrate that the proposed approach achieves better suppression of multipath ghosts and side/grating lobe artifacts and other significant superiorities, including priori wall information not being required, the preservation of weak targets, and robustness for different array deployments and building layouts.
This paper investigates and quantifies the advantages of a Full-Duplex (FD) transmitter/receiver pair in improving the secrecy rate of the system. We consider a linear precoder design for a multiple-inputmultiple-out...
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This paper investigates and quantifies the advantages of a Full-Duplex (FD) transmitter/receiver pair in improving the secrecy rate of the system. We consider a linear precoder design for a multiple-inputmultiple-output Gaussian wiretap channel, which comprises two legitimate nodes, i.e., Alice and Bob, operating in FD mode and exchanging confidential messages in the presence of a passive eavesdropper. Using the sum secrecy degrees of freedoms (sum SDoFs) as metric, we formulate an optimization problem with respect to Alice's and Bob's precoding matrices. In order to solve this problem, we first propose a cooperative secrecy transmission scheme, whose feasible set is sufficient to achieve the maximum sum SDoF. Based on that feasible set, we then determine in closed form the maximum achievable sum SDoF and also provide a method for constructing the precoding matrix pair, which achieves the maximum sum SDoF. The latter pair would be near-optimal in terms of the achievable secrecy sum rate in the high signal-to-noise ratio (SNR) regime. By providing the maximum achievable sum SDoF as a function of the number of antennas, one could select the optimal system parameters to further maximize the achievable sum SDoF. We use simulations to evaluate the performance of the proposed precoding matrices in realistic channel scenarios and at various levels of the SNR.
A novel transceiver antenna selection (TRAS) strategy selecting a pair of antennas for transmission and reception at terminal sources for full-duplex amplify-forward multi-input multi-output two way relay networks is ...
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A novel transceiver antenna selection (TRAS) strategy selecting a pair of antennas for transmission and reception at terminal sources for full-duplex amplify-forward multi-input multi-output two way relay networks is proposed. Antenna pair is selected in accordance with maximum and second maximum signal to self-interference-plus-noise ratio between the sources and relay, where the terminal sources and relay are full-duplex. Unlike reciprocal channel gains, forward and backward paths between the sources and relay are taken to be different. With four different antenna selection (AS) scenarios, the exact sum outage probability (SOP) for fading self-interference (SI) and the exact, approximated, and asymptotic SOP expressions for nonfading SI over Rayleigh fading channels are derived and validated via Monte Carlo simulation technique. The proposed AS strategy uses all antenna space for either transmission or reception which results in a reduction in total number of antennas at each terminal node. It is shown that performance can be significantly improved by usage of offered TRAS strategy at terminal sources. For example, up to 25 dB gain is obtained for five antennas at the sources with respect to no selection case of two antennas. In addition, it outperforms the selection strategy using maximum paths from two divided antenna sets at each source, where one set is only used for transmission and the other one for reception. The diversity order of the system is proven to be dependent on SI and varies between zero and minimum of the total number of antennas of two sources minus 1. For different SI values, optimum power allocations are demonstrated and factors affecting optimum relay location are also elaborated. Each AS scenario produces the lowest SOP for different combinations of SI occurrences, power allocations, and relay locations.
According to the physical phenomena of atmospheric channels and wave propagation, the performance of wireless communication system can be optimized by simply adjusting its natural parameters. This way is economically ...
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According to the physical phenomena of atmospheric channels and wave propagation, the performance of wireless communication system can be optimized by simply adjusting its natural parameters. This way is economically more favorable than consuming more power or using additional processing techniques. In this letter for the first time, an optimization problem is developed on the performance of a free-space optical multi-input multi-output (FSO-MIMO) communication system. In addition, it is the first time that the optimization of the FSO system is developed under saturated atmospheric turbulence. In order to get closer to the actual results, the effect of pointing error is taken into considerations. Assuming multiple phase-shift keying and differential phase-shift keying modulation schemes, new closed-form expressions are derived for bit error rate (BER) and outage probability (P-out) of the proposed structure. Furthermore, an optimization problem is developed taking into account the equivalent beam waist as variable parameter, and BER as objective function, there is no constraint in this system. Obtained results can be a useful outcome for FSO-MIMO system designers in order to mitigate the effects of pointing error as well as atmospheric turbulence, and thus, achieve optimum performance.
This paper concerns with the non-linear system having multiple-inputs multiple-outputs (MIMO). The plant mainly comprises: bench-top helicopter, tail and main rotor of a helicopter system. The dynamics are presented w...
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This paper concerns with the non-linear system having multiple-inputs multiple-outputs (MIMO). The plant mainly comprises: bench-top helicopter, tail and main rotor of a helicopter system. The dynamics are presented with control methodologies where a conventional strategy proves the instability of the system while the deadbeat and sliding mode control with linear matrix inequality regulates the future estimates. There have been disturbances like presence of unwanted ripples in the output of the non-linear systems (in case of stability also after 100 s) and in the tracking of states accurately by updating the minimization error regularly. These problems originate mainly from the rotor section and are visited carefully by studying the dynamics of the blade, whereas, the design of filter makes the solution more appealing. The adaptive filter is capable of handling the frequency spectra of noise (reducing noise by 10 dB), Euler angle deviations and travel angle accurately. Also, the stability analysis does not con firm the behavior in the case of bounded and a varying range of initial angular velocity. Hence, the problem of fluctuations is overcome by deadbeat and SMC-LMI approach which not only improved the ripples but also allowed the final response of the future states to be more exact and noiseless. As the previous research involved in position tracking (either translational or rotational) of these MIMO systems was concerned with software tools like MATLAB. This paper justifies its validation tested experimentally on OPAL RT hardware. The key findings involve the comparison of frequency spectra, the Euler deviation plot compared to CSL Helicopter and the three set-point variations providing accuracy in results in four modes - desired, actual, with controller-without filter and with controller-with filter. The use of adaptive filter with controllers have encouraged the suppression of noisy waveforms in the bench-top system very smoothly. The details regarding hardwar
An ultra-wideband, (UWB), multi-inputmultioutput, (MIMO), metamaterial-inspired antenna has been proposed in this paper. The wideband and high isolation is achieved through using Defected Ground Structure, (DGS), and...
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ISBN:
(纸本)9781538682746
An ultra-wideband, (UWB), multi-inputmultioutput, (MIMO), metamaterial-inspired antenna has been proposed in this paper. The wideband and high isolation is achieved through using Defected Ground Structure, (DGS), and Complementary Split Ring Resonators, (CSRR). The compact UWB antenna provides circular polarization, (CP), in some desired frequencies which makes it a suitable candidate for wireless applications and radar systems. Acceptable agreement between simulation and measured results is obtained. The proposed structure can be an appropriate candidate for modern wireless systems.
This paper proposes an innovative dual-input dual-output (DIDO-DC) DC-DC converter for the DC microgrid applications. The proposed converter is derived from the classic buck-boost DC-DC converter. The converter has fo...
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ISBN:
(纸本)9781538693155
This paper proposes an innovative dual-input dual-output (DIDO-DC) DC-DC converter for the DC microgrid applications. The proposed converter is derived from the classic buck-boost DC-DC converter. The converter has four IGBTs, two inductors, two filter capacitors and three diodes to integrate two input sources and two loads. Using this converter topology, both the loads can be powered even when one of the input sources is not available. Compared to the conventional topologies, the proposed topology has fewer component counts and low voltage stresses which improve the converter efficiency. The output voltage expressions of the DIDO-DC converter are derived from the analytical waveforms for the buck-boost mode of operation. To verify the operation of the converter, the simulation studies have been carried out using PSCAD 4.5.1 (R) software. The experimental prototype of the converter is fabricated and tested successfully in the laboratory. The measured experimental results are also presented in this paper. Finally, the performance comparison of the DIDO-DC converter with the conventional topologies is discussed.
In this paper the application of robust Fractional Order Proportional-Integral (FO-PI) autotuning control strategy is presented and applied to heterogeneous dynamic systems using decentralized control. The automatic t...
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In this paper the application of robust Fractional Order Proportional-Integral (FO-PI) autotuning control strategy is presented and applied to heterogeneous dynamic systems using decentralized control. The automatic tuning of controller gains is based on a single sine test, with user defined robustness margins guaranteed. Its performance is compared against two other fractional order controllers based on PI gain-crossover autotuning method and Internal Model Control (IMC). The closed loop control simulations applied on the heterogeneous dynamic systems indicate that the proposed method performs properly. (C) 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
Just like orthogonal frequency division multiplexing (OFDM) systems, the large peak-to-average power ratio (PAPR) as one of the main shortcomings still exists in multi-input multi-output (MIMO) OFDM systems. Interleav...
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ISBN:
(纸本)9783319959573;9783319959566
Just like orthogonal frequency division multiplexing (OFDM) systems, the large peak-to-average power ratio (PAPR) as one of the main shortcomings still exists in multi-input multi-output (MIMO) OFDM systems. Interleaving scheme is one of the attractive technologies for PAPR reduction and it can be directly used for each transmit antenna in MIMO-OFDM systems, called as ordinary interleaving scheme. In this paper, an improved interleaving scheme for PAPR reduction in MIMO-OFDM systems is proposed. Different from ordinary interleaving scheme, which transmit antenna is selected to perform the interleaving in proposed interleaving scheme is dominated by PAPR values of OFDM candidate sequences. Namely, the proposed interleaving scheme reorders the sequence from the antenna with the highest PAPR in the successive step after the PAPR of the original OFDM sequences are calculated. As a result, the proposed interleaving scheme can obtain better PAPR reduction performance compared with ordinary interleaving scheme.
A compact multi-band multi-input multi-output (MIMO) antenna with high isolation is proposed for C and X bands applications. The antenna consists of two trapezoidal-shaped patches printed on FR-4 substrate with a thic...
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A compact multi-band multi-input multi-output (MIMO) antenna with high isolation is proposed for C and X bands applications. The antenna consists of two trapezoidal-shaped patches printed on FR-4 substrate with a thickness of 1.6 mm and compact size of 17 mm×42 mm. Defected ground structure (DGS) is wisely embedded in antenna body to reduce the mutual coupling between the antenna elements. This modification suitably enhances the isolation by 30dB in C-band extended from 6.6 GHz to 7.6 GHz and by 17 dB in X-band between 8.3 GHz to 10 GHz. Moreover, five meander line rectangular patches are properly included to further improve the mutual coupling and eliminate the antenna size increment, simultaneously. The aforementioned meander lines also improve impedance bandwidth of the antenna as well as impedance matching over the entire frequency band. Close agreement of simulated and measured results confirm the antenna outperformance. Design, simulation, and performance analysis of the proposed antenna is discussed in detail.
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