2017/3
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- ItemWireless Powered Relaying Networks Under Imperfect Channel State Information: System Performance and Optimal Policy for Instantaneous Rate(Společnost pro radioelektronické inženýrství, 2017-09) Dinh-Thuan Do; Hoang-Sy Nguyen; Voznak, Miroslav; Thanh-Sang NguyenIn this investigation, we consider wireless powered relaying systems, where energy is scavenged by a relay via radio frequency (RF) signals. We explore hybrid time switching-based and power splitting-based relaying protocol (HTPSR) and compare performance of Amplify-and-Forward (AF) with Decode-and-Forward (DF) scheme under imperfect channel state information (CSI). Most importantly, the instantaneous rate, achievable bit error rate (BER) are determined in the closed-form expressions under the impact of imperfect CSI. Through numerical analysis, we evaluate system insights via different parameters such as power splitting (PS) and time switching (TS) ratio of the considered HTPSR which affect outage performance and BER. It is noted that DF relaying networks outperform AF relaying networks. Besides that, the numerical results are given to prove the optimization problems of PS and TS ratio to obtain optimal instantaneous rate.
- ItemWavelet Support Vector Machine Algorithm in Power Analysis Attacks(Společnost pro radioelektronické inženýrství, 2017-09) Hou, Shourong; Zhou, Yujie; Liu, Hongming; Zhu, NianhaoTemplate attacks and machine learning are two powerful methods in the field of side channel attack. In this paper, we aimed to contribute to the novel application of support vector machine (SVM) algorithm in power analysis attacks. Especially, wavelet SVM can approximate arbitrary nonlinear functions due to the multidimensional analysis of wavelet functions and the generalization of SVM. Three independent datasets were selected to compare the performance of template attacks and SVM based on various kernels. The results indicated that wavelet SVM successfully recovered the offset value of the masked AES implementation for each trace, which was obviously 5 to 8 percentage points higher than SVM-RBF. And also, the time required was almost reduced by 40% when using the optimal parameters of wavelet SVM. Moreover, wavelet SVM only required an average of 5.4 traces to break the secret key for the unmasked AES implementation and less than 7 traces for the masked AES implementation.
- ItemA Blind Adaptive Color Image Watermarking Scheme Based on Principal Component Analysis, Singular Value Decomposition and Human Visual System(Společnost pro radioelektronické inženýrství, 2017-09) Imran, Muhammad; Harvey, Bruce A.A blind adaptive color image watermarking scheme based on principal component analysis, singular value decomposition, and human visual system is proposed. The use of principal component analysis to decorrelate the three color channels of host image, improves the perceptual quality of watermarked image. Whereas, human visual system and fuzzy inference system helped to improve both imperceptibility and robustness by selecting adaptive scaling factor, so that, areas more prone to noise can be added with more information as compared to less prone areas. To achieve security, location of watermark embedding is kept secret and used as key at the time of watermark extraction, whereas, for capacity both singular values and vectors are involved in watermark embedding process. As a result, four contradictory requirements; imperceptibility, robustness, security and capacity are achieved as suggested by results. Both subjective and objective methods are acquired to examine the performance of proposed schemes. For subjective analysis the watermarked images and watermarks extracted from attacked watermarked images are shown. For objective analysis of proposed scheme in terms of imperceptibility, peak signal to noise ratio, structural similarity index, visual information fidelity and normalized color difference are used. Whereas, for objective analysis in terms of robustness, normalized correlation, bit error rate, normalized hamming distance and global authentication rate are used. Security is checked by using different keys to extract the watermark. The proposed schemes are compared with state-of-the-art watermarking techniques and found better performance as suggested by results.
- ItemAsymmetric Turbo Code for Coded-Cooperative Wireless Communication Based on Matched Interleaver with Channel Estimation and Multi-Receive Antennas at the Destination(Společnost pro radioelektronické inženýrství, 2017-09) Mughal, Shoaib; Yang, Fengfan; Ejaz, Saqib; Ahmed, Syed Hassan; Umar, RahimThis paper investigates the multiple relay coded-cooperation scheme based on asymmetric turbo code (ATC) with multiple receive antennas over Rayleigh block fading channels. An encoding scheme based on ATC is proposed for coded-cooperation i.e. distributed asymmetric turbo code (DATC). The code matched interleaver (CMI) is selected by a rigorous comparison with a uniform-random interleaver (URI). This optimum choice of interleaver at the relay nodes provides maximum benefit from DATC coded-cooperation scheme. Practically in any wireless communication system, the channel side information (CSI) is usually unknown at the receiver. Therefore, spatial normalized least mean square (NLMS) adaptive transversal filters are employed to estimate the CSI at the destination node. Moreover, in coded-cooperation scheme, the effectiveness and validation of spatial NLMS adaptive transversal filters is also verified by simulation results. Quadrature phase shift keying (QPSK) is used in coded-cooperation scheme and corresponding soft-demodulators are employed along with joint iterative soft-input soft-output (SISO) decoder at the destination node. Monte Carlo simulations shows that the proposed scheme incorporates coding gain, diversity gain and cooperation gain successfully, which eventually results in net gain of 2.7 to 3.5 dBs over non-cooperation ATC counterpart.
- ItemEvaluation of Computing Symmetrical Zolotarev Polynomials of the First Kind(Společnost pro radioelektronické inženýrství, 2017-09) Kubak, Jan; Sovka, Pavel; Vlcek, MiroslavThis report summarize and compares with each other various methods for computing the symmetrical Zolotarev Polynomial of the first kind and its spectrum. Suitable criteria are suggested for the comparison. The best numerical stability shows the method employing Chebyshev polynomial recurrence. In case of the polynomial spectrum computation the best method is the one using the difference backward recursion introduced by M. Vlcek. Both methods are able to generate the polynomial of high degree up to, at least, 2000, using 32-bit IEEE floating point arithmetics.