Zhuang Zhao-wen

Band Characteristics of SINR Polarization Filter

The band characteristics of the signal-to-interference-and-noise-ratio polarization filter to one signal in the presence of single noncoherent, purely polarized interference are investigated. The formulae of the filter band width on the polarization tracks and in the whole polarization region are presented. The quantitative description and the characteristic curves of the band scale are also given

Throughput analysis of IEEE 802.11 DCF over correlated fading channel in MANET

The throughput of 802.11 DCF over correlated fading channel in MANET are investigated in this paper. By obtaining the analytical representation of saturation throughput of 802.11 DCF over correlated fading channel, we get the impact of frame length and the mobile speed on throughput. Study shows the throughput decreases with the increase of mobile velocity and there exists an optimal frame length to maximize throughput under a certain velocity. Moreover, the optimal length is independent of the number of nodes.

Frequency modulated radar signals based on high dimensional chaotic maps

High dimensional chaotic maps have more complicated structures and better anti-jamming performances. Frequency modulated radar signals based on high dimensional chaotic maps are proposed. The signal model is presented, characteristics are analyzed, and comparison among ID Bernoulli map, 2D Cat map and uniform random noise with different series length is made in the paper. Simulations show well performances of the proposed signal.

Instruction-Level Optimization of H.264 Encoder Using SIMD Instructions

The latest video coding standard H.264/AVC is promising for its high coding performance with the cost of significantly higher complexity. In this paper, instruction-level optimization of H.264 encoder is proposed by exploiting single-instruction-multiple-data (SIMD) instructions. The key modules in H.264 encoder, such as SAD calculation, integer transform and inverse integer transform, SATD calculation and 1/4 pixel interpolation, are speed up. The simulation results on several video sequences show that our proposed instruction-level optimization achieves a speed-up factor of 1.3 up to 12 for every key module. The overall encoder speed-up gain is about twice without introducing serious quality degradation. The proposed instruction-level optimization is joined with algorithm optimization for X.264 encoder, and real-time encoding is achieved for video sequences in 4CIF format

Joint Spectrum estimation of Polarization and Space

The Joint Spectrum of Polarization and Space is constructed for the first time, which can depict the EM signal more completely. Based on the polarization sensitive antenna array, the joint spectrum is defined and the analytic function of joint spectrum is presented by MUSIC method. The discrimination power of joint spectrum is discussed theoretically in details. The polarization domain does not provide the same resolution capabilities as the other domains, when exploited alone. The simulations verify the superiority of the joint spectrum and coincide with the theoretical analysis. It is shown that the joint spectrum outperforms the spatial spectrum in characteristic detection and estimation.

Efficient Intra Mode Prediction Decision for MPEG-2 To H.264/AVC Transcoding

The wide deployment of MPEG-2 video and the extra benefits of the features introduced by H.264/AVC, create a strong need for video transcoding between these two standards. The key issue in video transcoding is to minimize the complexity while maximizing the quality. After analyzing the differences and similarities between these two standards, such as intra coding, an efficient intra prediction mode decision algorithm is proposed for MPEG-2 to H.264 video transcoder. It reuses the side information gathered in the video decoding stage to simplify the mode and direction decision process for intra prediction. Experimental results demonstrate that, compared with cascaded pixel video transcoding (CPDT), the proposed approach can maintain similar PSNR and bitrate, while considerably reducing the computational complexity. Therefore, it can be used as part of an efficient MPEG-2 to H.264 transcoder

Parameters Estimation for Generalized K-Distributed Clutter Model

In this paper, a novel parameter estimation algorithm is provided for generalized k-distributed clutter model based on the parameter decoupling technology. This estimation algorithm converts a 4-D nonlinear optimization problem into a 1-D optimization problem, which can not only improve the estimation performance, but also reduce the calculation burden and the number of necessary clutter samples. Finally, the simulation experiment is carried out to prove the validity and veracity of the algorithm proposed in this paper

Modeling of multirate signal in radar target recognition

Considering the uncertain for rotating velocity of spatial target and period of radar observation, there exists sampling rate variance between radar returns and template data, which decreases the degree of matching. In this paper, the autoregressive moving average (ARMA) model in multirate is provided, through which the power spectral density (PSD) of radar turns can be developed in the scale of template data, and then data can be matched in the same scale. Experimental result shows the validity of proposed method.

Radar Micro-motion Target Resolution

Micro-motion such vibration and rotation induces unique phase modulation or Doppler modulation and offers a new way of characterizing objects. When multiple vibration/rotation targets detection and identification are considered, the echo signal is multi-component sinusoidal modulation signal. So far multi-target resolution is still a major challenge facing radar signal processing community. In this paper, A new conception, multi-target micro-Doppler is introduced, and then B-distribution (BD) is applied to implement micro-motion target resolution (MMTR). Based on multi-target micro-Doppler, a complete scheme is presented for micro-motion target resolution. BD for resolving multiple vibration/rotation targets is demonstrated with synthetic data, and simulation results confirm our expectations

Novel biphase code — Integrated sidelobe suppression code

A kind of novel binary phase code named sidelobe suppression code is proposed in this paper. It is defined to be the code whose corresponding optimal sidelobe suppression filter outputs the minimum sidelobes. It is shown that there do exist sidelobe suppression codes better than the conventional optimal codes—Barker codes. For example, the sidelobe suppression code of length 11 with filter of length 39 has better sidelobe level up to 17dB than that of Barker code with the same code length and filter length.