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Because wireless network coding technology may increase the total throughput in wireless networks, it has attracted a lot of attentions. However, there is few work focusing on wireless network coding over fading channels. In fact, signal fading usually occurs in wireless communications, resulting in the performance degradation of wireless networks seriously in some scenarios. To improve the throughput...
This paper proposed a novel robust oblivious watermarking scheme in the spatial domain suitable for 3-D mesh object, which combines the principal component analysis (PCA) method with the construction of cone bins. Firstly, PCA is used to calculate the eigenvectors of covariance matrix of vertex coordinates. Then the object is rotated and translated so that its center of mass and the three eigenvectors...
In this paper, the performance of an ultra-wideband (UWB) communication system employing orthogonal pulse position modulation (PPM) and non-orthogonal pulse position modulation (NPPM) is considered. Time hopping (TH) is used to decrease the effect of multiuser interference. It is shown that for a large number of users, NPPM provides better bit error rate (BER) performance than PPM. We also determine...
We present a USB-based, highly directional, and portable microphone array device that delivers a crisp, clear and noise-reduced speech signal. This device consists of four linearly distributed microphone sensors and a filter-and-sum beamformer designed using broadband beam-forming algorithm. The device has a narrow acoustic beam pattern and identical frequency responses for almost all speech bands...
The performance of the SAGE algorithm in channel parameter estimation could be severely degraded by the error accumulated from the interference cancellation (IC) stage as each path in the channel is estimated sequentially. This is a direct result of removing inaccurate estimate of the interfering paths, and errors occurring at the IC stage for the first few paths will be accumulated and influence...
We consider the weighted sum rate maximization problem in downlink orthogonal frequency division multiple access (OFDMA) systems. A low complexity suboptimal resource allocation algorithm is proposed for joint optimization of multiuser subcarrier assignment and power allocation. This algorithm is based on an approximated primal decomposition based method, which is inspired from exact primal decomposition...
In this paper, a novel robust adaptive beamformer based on principal component regression (PCR) is derived. Unlike many existing methods, the proposed method is completely automatic (or so-called parameter-free), which means, it do not need the choice of user parameters. The performance of our approach is illustrated by numerical simulations and compared to other robust adaptive beamformers. The simulation...
The goal of this paper is to present an iterative robust adaptive beamformer using partial least squares (PLS) based on the generalized sidelobe canceller (GSC) parameterization of the minimum variance (MV) beamformer. The proposed method can be implemented simply as an iterative process and does not require the choice of a user parameter. The shrinkage properties and the relations among ridge regression...
In order to eliminate the musical noise remained in the results enhanced by short-time spectral attenuation techniques, this paper proposes a novel a priori SNR estimator. The proposed estimator is built on Burg-based power spectral estimation, which takes into account the properties in estimator of smoothness, accuracy and resolution, with the emphasis on their relationships and influences on de-noising...
A novel space-time block coding (STBC) scheme for four transmit antennas is proposed based on the binary phase shift keying (BPSK) constellation modulation. The new scheme achieves full diversity full rate. And it also can achieve linear decoding at receiver, so the decoding complexity at receiver is greatly reduced. Because the scheme can achieve full diversity, good performance can be obtained not...
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