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In this paper, a new beamformer is proposed for coherent signal reception with the assumption that the directions-of-arrival (DOA's) of the uncorrelated interferers are available. Here, the composite vector of the coherent sources is first estimated based on the use of a transformation matrix to eliminate the uncorrelated interferers. Then the optimum beamforming is performed based on the estimated...
ADBF is one of crucial techniques for phased array radar, which generally contains thousands of element. It usually adopts subarray configuration and can get only digital outputs of subarrays. Direct subarray weighting(DSW) configuration based on linearly constrained minimum-variance(LCMV) is an effective solution for ADBF, while the performance degrades in the presence of array imperfections such...
A coding scheme for the Gaussian wiretap channel based on low-density parity-check (LDPC) codes is presented. The messages are transmitted over punctured bits to hide data from eavesdroppers. It is shown by means of density evolution that the BER of an eavesdropper, who operates below the code's SNR threshold and has the ability to use a bitwise MAP decoder, increases to 0.5 within a few dB. It is...
The fading number of a noncoherent two-user Rician fading channel is derived. The fading number is the second term in the high-SNR expansion of the sum-rate capacity of this multiple-access channel. It is shown that the fading number is identical to the fading number of the single-user Rician fading channel that is obtained when the user seeing the worse channel is switched off.
A novel heterogeneous cooperative relay channel model is proposed in this article. It can integrate various wireless access systems into one entity and improve the spectrum efficiency remarkably. According to the characteristics of the heterogeneous and conventional homogeneous cooperative relay channel model, the outage probability performance is investigated over Nakagami-m fading model. A numerical...
This paper presents a novel evolutionary algorithm based on a hybrid of Taguchi method and particle swarm optimization (PSO), and thus is called HTPSO. First, the nonlinear nano-positioning system is approximated by the Takagi-Sugeno (T-S) fuzzy model. Second, the parallel distributed compensation (PDC) is designed to control the piezoelectric system. Last, the parameters of the fuzzy controller are...
3GPP LTE specification is stable now in release 8. To meet much higher requirements than release 8, 3GPP has initiated the LTE-A (LTE-Advanced) study item. In LTE-A, CoMP (coordinated multiple point transmission and reception) and CA (carrier aggregation) are two new features. CoMP is used to improve coverage and to increase cell-edge throughput. It is considered as an effective approach for ICIC...
We consider the problem of spectrum sensing in cognitive radio networks. In our previous work we have developed DualCUSUM, a distributed algorithm for change detection and used it for cooperative spectrum sensing. The algorithm is based on sequential change detection techniques which optimally use the past observations. But DualCUSUM requires the knowledge of the channel gains for each of the secondary...
The conventional audio watermarking methods have the following deficiencies: 1) the embedded watermarking signal bits are too less; 2) the embedded image watermarking is directly reduced to one-dimensional space and then embedded in audio signals, so the watermarking pre-process is too simple which reduce the security. To address these problems, a novel Audio watermark pre-process Algorithm is proposed...
This paper evaluates the efficacy of the recursive least squares (RLS) in adaptive noise canceller (RLS-ANC) for fast extraction of somatosensory evoked potentials (SEPs). The RLSANC method was verified by simulation of electroencephalography (EEG) and Gaussian noise contaminated SEP signals at different signal-to-noise ratios (SNRs). RLS was found to converge faster than the least mean squares (LMS)...
Image based rendering is a promising way to produce arbitrary views of a scene using images instead of object models. However, depth variations and occlusions cause blurring in the rendered images. The solution is to use some geometrical information in order to steer the interpolation filters according to the depth. The level of detail of this geometry is often predetermined. In this paper, we present...
We consider the problem of estimating the central direction of arrival (DOA) of multiple coherently distributed sources. This problem is encountered due to the presence of local scatters in the vicinity of a transmitter or due to signals propagating through a random inhomogeneous medium. Since the integral steering vector of coherently distributed source can be deduced to be a Schur-Hadamard product...
In this paper, the nonlinear approximation by piecewise constants is investigated, and a partition method for balancing the total variation over the intervals is proposed. Based on this method, the result of Kahane is proved, and the application in signal restoration is given. Finally, the numerical experiments are conducted to assess the proposed method in comparison with different wavelet thresholding...
Overlap decomposition is one of the difficulties in spike sorting. A method based on genetic algorithm is proposed to deal with the overlapped signal from two single waves in this paper. Specifically, with the reliable signal wave templates given, the methods for overlap signals and for single wave signals are used simultaneously to process the unknown data from the signal acquisition equipment, and...
Estimation of the instantaneous frequency (IF) of nonlinear FM signals with additive Gaussian noise is considered. An algorithm for the IF estimation is proposed based on Wigner-Ville distribution (WVD) maxima and local singular value decomposition (SVD).Simulation result shows that the proposed method is valid for nonlinear FM signals.
The velocity time series signal of the flow field in impinging stream mixer (ISM) contains a lot of dynamic information. It is the comprehensive reflection of many factors such as the physical properties, the motion characteristics and the flow structures of the fluid. The measured velocity signal denoising process is the key to improve the signal reliability and accuracy. A de-noising method for...
The capacity of feedback links is typically limited and shared by multiple users. So this paper studies the impacts on multiple input multiple output (MIMO) broadcast channel (BC) when limited feedback capacity is shared among multiple users. Our mathematical analysis proves that in the high signal-to-noise ration (SNR) region, allocating the whole feedback capacity to a single user is the optimal...
Raman spectroscopy is able to identify plastic components, similar to infrared absorption. This paper shows the potential application of Raman spectroscopy to post-consumer plastic recycling when massive and accurate sorting processes are required. We developed a high-speed Raman apparatus for scanning with an appropriate wavelength region of less as 1.5 milliseconds, and an analyzing methodology...
We develop accurate and robust one-dimensional EXIT chart methods to design raptor codes with binary and higher-order modulations on AWGN channels over any desired range of SNRs. We formulate the check-node degree distribution optimization as a linear program that optimizes a suitable objective function of the desired operating points. The throughput curves predicted by the analysis are easily compared...
Unequal error protection (UEP) and rateless coding are both methods used to combat channel uncertainty. With a rateless code, the code rate automatically adapts to the channel quality through the use of incremental redundancy. However, a rateless code lacks the ability to differentiate priorities and all bits suffer the same long delay in poor channel conditions. In contrast, UEP ensures reliable...
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