Background: Orthogonal frequency division multiplexing has been regarded as one of the promising technologies for the optical access systems application. However, high peak-to-average power ratio will cause the signal distortion and enable the used amplifier to operate in nonlinear section. Methods: In this paper, a modified selected mapping technique is introduced for reducing the peak-to-aver...

Receiver diversity methods play a key role in combating the detrimental effects of fading in wireless communication and other applications. Commonly used linear diversity methods include maximal ratio combining, equal gain combining and antenna selection combining. A novel linear combining method is proposed where a universal orthogonal dimension-reducing space-time transformation is applied pr...

Communication is one of the important aspects of life. With the advancement in age and its growing demands, there has been rapid growth in the field of communications. Signals, which were initially sent in the analog domain, are being sent more and more in the digital domain these days. For better transmission, even single carrier waves are being replaced by multi carriers. Multi carrier system...

We propose a finite impulse response (FIR) minimum mean squared error (MMSE) decision feedback equalizer (DFE) for orthogonal multipulse modulated signals received through a multipath channel. Our system model accounts for both the loss of orthogonality caused by the multipath channel as well as intersymbol interference (ISI). First, we review previous work on the subject which used the zero-fo...

We study the problem of finding unitary submatrices of the discrete Fourier transform matrix. This problem is related to a diverse set of questions on idempotents on ZN , tiling ZN , difference graphs and maximal cliques. Each of these is related to the problem of interpolating a discrete bandlimited signal using an orthogonal basis.

In many applications noisy signals are measured. These signals has to be filtered and, sometimes, their derivative have to be computed. In this paper a method for filtering the signals and computing the derivatives is presented. This method is based on expansion onto transformed Legender polynomials. Numerical examples demonstrates the efficacy of the method as well as the theoretical estimates.

In order to reduce the influence of mutual interference between signals from different transmitters, novel orthogonal signals are designed for netted radar systems in this paper. Different stepped time interval pulse trains (STIPT) which are orthogonal are designed for spatially separated transmitting nodes. Because of the good autocorrelation and cross-correlation properties, mutual interferen...

The problem of estimating propagation delays of the orthogonal modulated signals in asynchronous DS-CDMA system over fading channels is treated in this paper. The system under study resembles the uplink of an IS-95 system. The channel is assumed to be a time-varing flat Rayleigh-fading channel. The shortcoming of the sliding correlator as the standard method of code acquisition is examined and ...

The ECG finds its importance in the detection of cardiac abnormalities. ECG signal processing in an embedded platform is a challenge which has to deal with several issues. Noise reduction in ECG signal is an important task of biomedical science. ECG signals are very low frequency signals of about 0.5Hz100Hz. There are various artifacts which get added in these signals and change the original si...

We consider a relay channel for which the following assumptions are made : 1. The source-destination and relay-destination channels are orthogonal (frequency division relay channel) ; 2. The relay implements the decode-and-forward protocol ; 3. The source and relay implement the same channel encoder namely a convolutional encoder ; 4. They can use arbitrary and possibly different modulations. I...