检索结果-南通市图书馆

CHANNEL ESTIMATION OF MULTI-RATE DS-CDMA signalS IN SLOW FADING MULTIPATH CHANNELS

在线全文

cnki会议

学校读者我要写书评

暂无评论

Journal of Electronics(china) 2003年第5期20卷 321-325页

作者： Zhang Yingguang Zhang Linrang Liao Guisheng (national Key laboratory for radar signal processing, xidian university, xi’an 710071) national Key laboratory for radar signal processing Xidian University Xi'an 710071

In Direct-Sequence Code Division Multiple Access(DS-CDMA) mobile communi-cation systems, it is very important to obtain accurate estimation of the channel parameters,especially that of the propagation delay. But the near-far problem may make the estimationcomplicated and can degrade the estimation performance significantly. In this paper, an efficientMaximum Likelihood (ML) method is presented for channel parameter estimation of multi-rateDS-CDMA systems in slow fading multipath channels in a near-far scenario. The algorithmextended the ML approach to multi-rate DS-CDMA systems, and proposes decomposing a multi-dimensional optimization problem into a series of one-dimensional optimization and has improvedcomputational efficiency. Theoretical analysis and numerical examples show that the estimatorproposed is effective and near-far resistant.

关键词： CDMA Channel estimation Multi-rate Near-far problem Maximum likelihood Correlator

维普期刊数据库

FAST MUSIC SPECTRUM PEAK SEARCH VIA METROPOLIS-HASTINGS SAMPLER

在线全文

学校读者我要写书评

暂无评论

Journal of Electronics(china) 2005年第6期22卷 599-604页

作者： Guo Qinghua Liao Guisheng national Key lab for radar signal processing Xidian University Xi＇an 710071 China

A fast MUltiple signal Classification (MUSIC) spectrum peak search algorithm is devised, which regards the power of the MUSIC spectrum function as target distribution up to a constant of proportionality, and uses Metropolis-Hastings (MH) sampler, one of the most popular Markov Chain Monte Carlo (MCMC) techniques, to sample from it. The proposed method reduces greatly the tremendous computation and storage costs in conventional MUSIC techniques i.e., about two and four orders of magnitude in computation and storage costs under the conditions of the experiment in the paper respectively.

关键词： MUltiple signal Classification (MUSIC) algorithm Metropolis-Hastlngs (MH)sampler Markov Chain Monte Carlo (MCMC)

维普期刊数据库

A STUDY OF REDUCED-RANK STAP

在线全文

学校读者我要写书评

暂无评论

Journal of Electronics(china) 2000年第4期17卷 289-296页

作者： Zhang Liang Bao Zheng Liao Guisheng (Key lab. for radar signal processing, xidan university, xi’an 710071, china)

This paper starts with the discussion of the principle of Reduced-Rank (RR) Space-Time Adaptive processing (STAP). It is followed by a dedication of the upper bound performance of all eigen-based RR methods provided by Cross Spectral Method (CSM) under the condition of a given processor rank and an identical secondary sample size. A performance comparison between two RR STAP processors with prefixed structure and CSM is performed by the means of simulations. It is shown that the performance of time pre-filtering followed by jointly localized STAP structure (i.e. 3DT-SAP) is very close to the upper bound and thereby it is an effective RR approach.

关键词： Airborne phased array radar Reduced-Rank STAP (RR STAP) Cross Spectral Method (CSM) Clutter suppression Detection performance

维普期刊数据库

radar Automatic Target Recognition Based on Complex High-Resolution Range Profiles

在线全文

学校读者我要写书评

暂无评论

Radar Automatic Target Recognition Based on Complex High-Res...

2006 CIE International Conference on radar

作者： Lan Du Hongwei Liu Zheng Bao national lab.of radar signal processing xidian university xi’an china

radar high-resolution range profile （HRRP） has received intensive attention from the radar automatic target recognition （RATR） ***,complex HRRPs are not fully used for RATR but only their amplitude vectors,while the phase information of them is discarded due to the fact that the initial phase of a complex HRRP is strongly sensitive to target position ***,the phase information of complex HRRPs may also contain valuable target discriminant information,which may further improve the recognition *** paper concerns RATR using complex *** deal with the initial phase sensitivity of complex HRRPs,we extract the complex HRRPs’ feature subspace within each target-aspect sector of each target via principal component analysis （PCA） as the corresponding template during the training phase,while in the test phase,project the test sample onto each feature subspace and search the optimal approximation of the test sample with the minimum reconstruction error to decide which target the test sample belongs *** is shown that the whole process is independent of the initial phases of complex ***,to make the proposed recognition method more practical,a fast time-shift compensation algorithm is *** the recognition experiments based on measured data,the proposed recognition method using complex HRRPs achieves better recognition results than that using only the amplitude vectors of the complex HRRPs.

关键词： radar automatic target recognition (RATR) complex high-resolution range profile (complex HRRP) initial phase sensitivity time-shift sensitivity principal component analysis (PCA) minimum reconstruction error approximation

An approach to sample broadband radar signal with low-rate ADC using adaptive beamforming technique

在线全文

cnki会议

学校读者我要写书评

暂无评论

An approach to sample broadband radar signal with low-rate A...

2006 CIE International Conference on radar

作者： Ma Lun Li Zhenfang and Liao Guisheng national lab.of radar signal processing xidian university xi’an china

To directly sample broadband radar signal with high-rate Analog-to-Digital Converter（ADC） suffers from high cost and low sampling *** this paper a novel method is presented to sample a wide-band signal with multiple low-rate ADC channels by using adaptive beamforming *** method has the advantages of low cost,low sampling rate,high precision,easy implementation,and it is robust to channel *** effectiveness of the proposed approach is verified by simulated data.

关键词： Analog-to-Digital Converter(ADC) Adaptive beamforming Multi-channel sampling

Multiuser detection and independent component analysis——Progress and perspective

在线全文

cnki会议

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2002年第7期 15-22页

作者： JIAO Licheng , MA Haibo and LIU Fang( State Key laboratory for radar signal processing, xidian university, xi’an 710071, china) State Key laboratory for radar signal processing Xidian University Xi'an 710071 China

The latest progress in the multiuser detection and independent component analysis (ICA) is reviewed systematically. Then two novel classes of multiuser detection methods based on ICA algorithms and feedforward neural networks are proposed. Theoretical analysis and computer simulation show that ICA algorithms are effective to detect multiuser signals in code-division multiple-access (CDMA) system. The performances of these methods are not identical entirely in various channels, but all of them are robust, efficient, fast and suitable for real-time implementations.

关键词： code division multiple access (CDMA) multiuser detection independent component analysis (ICA).

Impulse Wave Estimation based on Analytic Wavelet in UWB-radar

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Impulse Wave Estimation based on Analytic Wavelet in UWB-Rad...

第七届国际信号处理会议

作者： Min WANG Weimin YUAN Shunjun WU (national Key lab for radar signal processing xidian Univ. xi’an china 710071)

A method is discussed in this paper for analysis of received Ultra Wideband pulse in noise based on analytical wavelet transform. Using analytical version of wavelet, the feather of the impulse sha

关键词： analytical wavelet transform UWB impulse noise reduction time delay estimation.

Multistage decomposition algorithm for blind source separation

在线全文

cnki会议

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2002年第5期 60-64页

作者： FENG Dazheng, BAO Zheng and ZHANG xianda(Key laboratory for radar signal processing, xidian university, xi’an 710071, china) Key laboratory for radar signal processing Xidian University Xi'an 710071 China

A new algorithm for blind source separation is proposed, which only extracts the single independent component at each stage. The single independent component is acquired by an iterative algorithm for searching for the optimal solution of the defined cost function. Moreover, all the independent components are obtained by systematic multistage decomposition and multistage reconstruction. When there is spatially colored noise, the performance of this algorithm is advantageous over jointly approximated diagonalization of eigen-matrices (JADE) . Simulated results show that if the number of source signals is more than 25, its computational complexity is lower than that of JADE.

关键词： blind source separation multistage decomposition multistage reconstruction criterion iteration algorithm.

Automatic Target Recognition based on SAR images and Two-Stage 2DPCA features

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Automatic Target Recognition based on SAR images and Two-Sta...

2007 Asian and Pacific Conference on Synthetic Aperture radar(APSAR 2007)

作者： Liping Hu Jin Liu Hongwei Liu Bo Chen Shunjun Wu national lab. of radar signal processing xidian university xi’an china 710071

2-dimensional Principal Component Analysis （2DPCA） has received more and more attentions in recent years,since it can evaluate the covariance matrix more accurate than PCA in extracting features from 2-dimensional images. However,a drawback of 2DPCA is that it needs more features than PCA because 2DPCA only eliminates the correlations between rows. In this paper,two-stage 2DPCA is proposed to extract features from synthetic aperture radar （SAR） images to further compress the dimension of features and decrease the recognition computation. Experimental results based on MSTAR data indicate that two-stage 2DPCA can decrease feature dimensions significantly,and the target recognition performance can be improved at the same time.

关键词：