Suppression to the cross-channel interference based on the short time Fourier transform

A new cross-channel interference suppression method is proposed to decrease the cross-channel interference in beat signals based on the short time Fourier transform （STY3＂） and the inverse short time Fourier transform （ISTFT） when the dual-orthogonal polarimetric frequency-modulated continu- ous wave （FMCW） radar adopts the opposite-slope linear frequency modulation signal pair in the simultaneous measurement mode. The STFT is applied only on the signals in the cross-interference intervals in the four polarimetric channels to decrease the computation complexity. A mask matrix for suppressing the interference is constructed using the constant false alarm ratio （CFAR） detection on the spectrograms by the STFY. The simulative results show that the cross-channel interference is effi- ciently suppressed by the proposed method. The comparison between the proposed method and the rejection method verifies the improved performance of the proposed method.

A SEMI-ANALYTICAL AND SEMI-NUMERICAL METHOD FOR SOLVING 2-D SOUND-STRUCTURE INTERACTION PROBLEMS

Based on the transfer matrix method and the virtual source simulation technique, this paper proposes a novel semi-analytical and semi-numerical method for solving 2-D sound- structure interaction problems under a harmonic excitation.Within any integration segment, as long as its length is small enough,along the circumferential curvilinear coordinate,the non- homogeneous matrix differential equation of an elastic ring of complex geometrical shape can be rewritten in terms of the homogeneous one by the method of extended homogeneous capacity proposed in this paper.For the exterior fluid domain,the multi-circular virtual source simulation technique is adopted.The source density distributed on each virtual circular curve may be ex- panded as the Fourier's series.Combining with the inverse fast Fourier transformation,a higher accuracy and efficiency method for solving 2-D exterior Helmholtz's problems is presented in this paper.In the aspect of solution to the coupling equations,the state vectors of elastic ring induced by the given harmonic excitation and generalized forces of coefficients of the Fourier series can be obtained respectively by using a high precision integration scheme combined with the method of extended homogeneous capacity put forward in this paper.According to the superposition princi- ple and compatibility conditions at the interface between the elastic ring and fluid,the algebraic equation of system can be directly constructed by using the least square approximation.Examples of acoustic radiation from two typical fluid-loaded elastic rings under a harmonic concentrated force are presented.Numerical results show that the method proposed is more efficient than the mixed FE-BE method in common use.

Fractional Fourier transform on R^(2)and an application

We focus on the L^(p)(R^(2))theory of the fractional Fourier transform(FRFT)for 1≤p≤2.In L^(1)(R^(2)),we mainly study the properties of the FRFT via introducing the two-parameter chirp operator.In order to get the pointwise convergence for the inverse FRFT,we introduce the fractional convolution and establish the corresponding approximate identities.Then the well-defined inverse FRFT is given via approximation by suitable means,such as fractional Gauss means and Able means.Furthermore,if the signal F_(α,β)f is received,we give the process of recovering the original signal f with MATLAB.In L^(2)(R^(2)),the general Plancherel theorem,direct sum decomposition,and the general Heisenberg inequality for the FRFT are obtained.

P×N IFFT FOR OFDM-BASED UWB SYSTEM

In this letter,P × N-pointIFFT is proposed to replace the N-point IFFT and analog fre-quency conversion in an Orthogonal Frequency Division Multiplexing (OFDM)-based Ultra-WideBand (UWB) system,and a new algorithm,named fast P × N-pointIFFT,is designed to reduce the com-plexity of the P × N-pointIFFT in the proposed scheme.

A Novel Approach with Time-Splitting Spectral Technique for the Coupled Schrdinger–Boussinesq Equations Involving Riesz Fractional Derivative

In the present paper the Riesz fractional coupled Schr6dinger-Boussinesq （S-B） equations have been solved by the time-splitting Fourier spectral （TSFS） method. This proposed technique is utilized for discretizing the Schrodinger like equation and further, a pseudospectral discretization has been employed for the Boussinesq-like equation. Apart from that an implicit finite difference approach has also been proposed to compare the results with the solutions obtained from the time-splitting technique. Furthermore, the time-splitting method is proved to be unconditionally stable. The error norms along with the graphical solutions have also been presented here.

Improvement and Analysis of Carrier-Interferometry Orthogonal Frequency Division Multiplexing System

This paper proposes to use Fast Fourier Transform （ FFT ） / Inverse Fast Fourier Transform （IFFT）, instead of vector-matrix multiplication, to implement the spreading/despreoding in Carrier-Interferometry Orthogonal Frequency Division Multiplexing （ CI/OFDM） and Pseudo-Orthogonal Carrier lnterferometry OFDM （PO-CI/OFDM）. That can improve the signal processing efficiency of CI/OFDM and PO-CI/OFDM systems by about 2N/log2N and 2N/（ 1 ＋ log2 N） times respectively and dose not make any difference to the system function and performance. Moreover, the effi- ciency benefits will increase with the increase of the number of sub-carriers. In addition to that, we point out that the transmitter of CI/OFDM is actually technically equivalent to that of a single-carrier system with cyclic-prefix and the receiver of CI/OFDM is a typical OFDM receiver with CI despreading. Hence the low Peak-to-Average Power Ratio （PA- PR） property and high anti-fading performance of CI/OFDM system can be well explained .