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Том 62, № 2 (2019)
- Год: 2019
- Статей: 4
- URL: https://journal-vniispk.ru/0735-2727/issue/view/10938
Article
PAPR Reduction in FBMC-OQAM Systems Based on Discrete Sliding Norm Transform Technique
Аннотация
This paper deals with the Peak to Average Power Ratio (PAPR) drawback appeared in Filter-Bank Multi-Carriers with Offset-QAM (FBMC-OQAM) which is the candidate waveform in 5G wireless communication systems. A post-Inverse Discrete Fourier Transform (IDFT) Discrete Sliding Norm Transform (DSNT) is proposed based on L2-metric and the norm of five samples at each sliding operation. The overlapping structure of FBMC-OQAM is considered in the proposed L2-by-5 DSNT formulation. It can significantly reduce the PAPR in FBMC-OQAM systems, which ensures a linear amplification at the High Power Amplifier (HPA) and avoids signal distortion. The main advantages of this technique are its lower computational complexity compared to the known techniques, and the fact that it does not require any Side Information (SI) at the receiver. Simulation results show that the L2-by-5 DSNT technique can achieve an improvement of 40% in PAPR reduction at CCDF = 10−3 compared to the original FBMC-OQAM system.
51-60
Adaptive Filtration of Radio Source Movement Parameters Based on Sensor Network TDOA Measurements in Presence of Anomalous Measurements
Аннотация
The methods based on TDOA measurements find wide application for localization of radio sources using wireless sensor networks. The need of taking into account the presence of anomalous measurement results often occurs in real conditions. Their appearance means a significant malfunction of sensor network components that results in divergence of traditional algorithms of Kalman filtration of radio source movement parameters. Based on the mathematical tools of mixed Markov processes in discrete time domain, the optimal and quasioptimal algorithms of adaptive filtration of radio source movement parameters were synthesized on the basis of TDOA measurements of sensor network in the presence of anomalous measurements. The optimal algorithm describes the evolution of joint a posteriori probability density of the vector of movement parameters and switching variables determining the type of measurement errors of network sensors. The quasioptimal algorithm obtained by linearization of the measurement equation involves the implementation of sequential technique of incoming data processing and performance of the Gaussian approximation of a posteriori probability density of radio source movement parameters. For the case considered in this paper using the statistical simulation, the developed quasioptimal algorithm makes it possible to recognize the appearance of anomalous errors of measurements with probability close to unity and eliminate their impact on the accuracy of determining the radio source movement parameters.
61-71
ECG Signal Characterization Using Lagrange-Chebyshev Polynomials
Аннотация
An ECG (electrocardiogram) is a signal representing a combination of potentials that reflect the electrical activity of the heart. These signals are often corrupted by artifacts of high magnitude and frequency during acquisition, storage and transmission. Addition of these artifacts may change the morphology of the ECG signals and can hinder accurate interpretations; hence proper characterization is required for better clinical evaluation. In this paper ECG signals from MIT-BIH database are characterized using polynomial interpolation method. In this method, initially Chebyshev nodes are suitably chosen in the desired ECG interval and then these nodes are utilized by Lagrange interpolation method for restoration of ECG signals. The results of the interpolation are further improved by segmenting the ECG signals into suitable number of segments using Bottom-Up time series segmentation approach. The performance of the proposed method is analyzed in terms of standard ECG performance parameters: mean absolute deviation, root mean square deviation, percentage root mean square difference error, signal to noise ratio and cross correlation. Results obtained are compared with existing methods and are found to be superior and diagnostically acceptable. Practical implementation areas of the proposed method are also explored.
72-85
ACS-Fed Wideband Mirrored Z- and L-Shaped Triple Band Uniplanar Antenna for WLAN Applications
Аннотация
A mirrored Z- and L-shaped printed uniplanar antenna has been proposed and developed in this paper for triple band applications. The developed geometry realizes simple radiating branches with 50 Ω Asymmetric Coplanar Strip (ACS) feedline and rectangular ground plane. It occupies a very compact area of 16×24 mm including the ground plane, the size of which is only 0.18×0.34λ, at the frequency of 2.3 GHz in free space. The simulated results obtained in the environment of CST Microwave Studio package have been compared with the measured results of antenna using the PNA N5222A Vector Network Analyzer, and a good agreement of results has been achieved. For −10 dB reflection coefficient the bandwidth is about 230 MHz in the band of 2.27–2.5 GHz, 200 MHz in the band of 3.65–3.85, and 1700 MHz in the band 5.2–6.9 GHz. The proposed uniplanar antenna is not only compact in size, but also has wide bandwidths that cover the Long Term Evolution (LTE), Wireless Broadband (WiBro), Worldwide Interoperability for Microwave Access (WiMAX), Wireless Local Area Network (WLAN) and Industrial Scientific and Medical radio band (ISM) applications.
86-95