Orthogonal frequency division multiplexing (OFDM) is a parallel transmission scheme for transmitting data at very high rates over time dispersive radio channels and sub carriers are used to carry that data. These subcarriers are orthogonal to each other. In an OFDM system, frame synchronization and frequency-offset estimation are extremely important for maintaining orthogonality among these sub...

The presence of residual carrier frequency offset (CFO) in an orthogonal frequency division multiplexing (OFDM) system leads to a loss of orthogonality between the subcarriers. This introduces inter-subcarrier interference and degrades the system performance significantly. In the literature, Liu and Tureli proposed a blind CFO estimation method based on the observation that in a typical OFDM sy...

For separating multiple speech signals given a convolutive mixture, time-frequency sparseness of the speech sources can be exploited. In this paper we present a multi-channel source separation method based on the concept of approximate disjoint orthogonality of speech signals. Unlike binary masking of singlechannel signals as e.g. applied in the DUET algorithm we use a likelihood mask to contro...

The densities of small linear structures (such as arithmetic progressions) in subsets of Abelian groups can be expressed as certain analytic averages involving linear forms. Higher-order Fourier analysis examines such averages by approximating the indicator function of a subset by a function of bounded number of polynomials. Then, to approximate the average, it suffices to know the joint distri...

In this paper, a simplified Generalized Code-Shifted Differential Chaos Shift Keying (GCSDCSK) whose transmitter never needs any delay circuits, is proposed. However, its performance is deteriorated because the orthogonality between substreams cannot be guaranteed. In order to optimize its performance, the system model of the proposed GCS-DCSK with power allocations on substreams is presented. ...

The approximate behavior of wavelets as differential operators is often considered as one of their most fundamental properties. In this paper, we investigate how we can further improve on the wavelet’s behavior as differentiator. In particular, we propose semi-orthogonal differential wavelets. The semi-orthogonality condition ensures that wavelet spaces are mutually orthogonal. The operator, hi...

Sampling a finite stream of filtered pulses violates the bandlimited assumption of the Nyquist-Shannon sampling theory. However, recent low rate sampling schemes have shown that these sparse signals can be sampled with perfect reconstruction at their rate of innovation. To reach this goal in the presence of noise, an estimation procedure is needed to estimate the time-delay and the amplitudes o...

The wavefunction for the multiparticle Schrödinger equation is a function of many variables and satisfies an antisymmetry condition, so it is natural to approximate it as a sum of Slater determinants. Many current methods do so, but they impose additional structural constraints on the determinants, such as orthogonality between orbitals or an excitation pattern. We present a method without any ...

The analytical performance of the subspace-based blind linear MMSE multiuser detection algorithm in general multipath multi-antenna CDMA systems is investigated. In blind multiuser detection, the linear MMSE detector of a given user is estimated from the received signals, based on the knowledge of only the spreading sequence of that user. Typically, the channel of that user must be estimated fi...

A new numerical method, based on the normalized Bernstein polynomials for solving singular integral equations of Abel type is presented here in this paper. We construct an othonormal family { } i n i b 0 = of polynomials of degree n from the th n degree Bernstein polynomials n i B and use them as a basis to approximate the known and unknown functions ) (x f and ) (x φ respectively in the Abel’s...