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With the rapid growth of user demands, and the limitations of third generation (3G) mobile communication systems, it is expected that fourth generation (4G) mobile systems are likely to reach the consumer market in another 4-5 years. 4G systems are expected to become a platform capable of providing increased bandwidth, higher data rates, and greater interoperability across communication protocols,...
This paper is to present a new space vector PWM algorithm for four- switch three-phase inverters (FSTPI) fed induction motor under DC-link voltage imbalance. By using reasonable mathematical transform, space vector PWM technique for FSTPI under DC-link voltage imbalance or ripples have been solved, which is based on the establishment of basic space vectors and modulation technique in similarity with...
This paper considers digital to analog conversion of OFDM signals which have been digitally upconverted to a digital IF (Intermediate Frequency). We examine the effect of clipping and quantization on the received constellations and the uncoded bit error rate (BER) and find that the clipping and quantization can be characterized as a gain and the addition of uncorrelated Gaussian noise. Extensive simulations...
Non-stationary signal modeling is a well addressed problem in the literature. Many methods have been proposed to model non-stationary signals such as time varying linear prediction and AM-FM modeling, the later being more popular. Estimation techniques to determine the AM-FM components of narrow-band signal, such as Hilbert transform, DESA1, DESA2, auditory processing approach, ZC approach, etc.,...
This paper presents a novel high performance generalized discontinuous pulse width modulation (GDPWM) algorithm for reduced current ripple without angle and sector estimation. The conventional space vector modulator with equal division of zero state vectors time is modified to generate different discontinuous modulating waves. A constant-variable mu ranging from 0 to 1 is used to generate infinite...
A distributed non cooperative power control game with pricing (NPGP) for multiple-input multiple-output (MIMO) multi-carrier direct sequence code division multiple access (MC -DS/ CDMA) system for different modulation is considered in this work. The utility functions for assaying the performance of MIMO MC-DS /CDMA for spectral efficient communication of the system carrying wireless data are envisaged...
In wireless sensor networks, the routing algorithms currently available assume that the sensor nodes are stationary. Therefore when mobility modulation is applied to the wireless sensor networks, most of the current routing algorithms suffer from performance degradation. The path breaks in mobile wireless networks are due to the movement of mobile nodes, node failure, channel fading and shadowing...
For low conversion ratios boost rectifier has a power factor less than unity when operated in discontinuous conduction mode and constant duty cycle. This paper proposes a simple duty cycle modulation technique to reduce the line harmonics and improve the power factor of the boost rectifier, even for low conversion ratios. A periodic voltage signal is used to vary the duty cycle of the boost switch...
Analytical solutions for the average symbol error rate of coherent M-ary frequency shift keying (MFSK) modulation schemes operating over frequency non-selective slow fading channels corrupted by additive white Gaussian noise (AWGN) are derived. Starting from the alternate expressions for integer powers (n < 5) of Gaussian Q function, the symbol error probabilities (SEP) are obtained using probability...
Filterbank transmultiplexer (FB TMUX) system has been considered as a kind of multicarrier communication technology. When there are interferences, the FB TMUX system has better performance than orthogonal frequency division multiplexing (OFDM) system, as filters which are used in the FB TMUX have better frequency responses than those of the OFDM. The FB TMUX can be efficiently implemented by using...
This work describes the strategies to improve the channel quality indicator (CQI) for multi-state channels in 802.16e (wimax) based systems. The method includes the use of Exponential effective SNR mapping (EESM) method as part of the modulation/coding selection process and the problems associated with this technique has been studied. MI-ESM (Mutual Information based Effective SNR mapping) SNR metric...
The implementation of a feed-back controller for a voltage source inverter for obtaining constant amplitude, constant frequency supply from an integrated wind/photovoltaic system has been presented in this paper. The steady state analysis of the wind-generator has been carried out and the critical wind speed above which it will supply the load has been determined. The various operating modes of the...
This paper addresses a new approach to data hiding that leads to a high data embedding rate of tens of kbps in a typical digital voice file transmission scheme. The purpose of the proposed method is restricted to offline voice transmission that uses stego speech files in wave format. The basic idea of the algorithm is to embed encrypted covert message in the unvoiced bands of spectrum of the cover...
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