A pre-placement individual net length estimation model and an application for modern circuits

With the advances in integrated circuit (IC) technology, managing the individual and total interconnect is becoming one of the main challenges facing designers. An individual a-priori length estimation model can be a useful tool in helping designers obtain lower net lengths and congestion of interconnect. In this paper, the main characteristics that need to be considered while designing an individual a-priori length estimation technique for today's integrated circuits are discussed. A model that includes some of the most prevalent characteristics is designed and tested using the most current benchmark circuits released by IBM. In addition, one application of the length estimation is proposed in which a predictor-corrector framework for clustering that can be used to improve the results of placement is implemented. This model shows that the corrector step can improve the final placement results by up to 33% for special cases.     

谱估计方法的通用矩阵表示与新的谱估计方法

本文指出几种常见的谱估计方法可以归结为同一数学问题并可用同一矩阵方程表示。从这通用矩阵表示可导出许多新的谱估计方法。本文还具体研究了相关阵特征矢量空间谱估计方法,得出一些有益的结论。     

基于分段MDCFT的LFM信号参数估计方法

在修正离散线性调频傅里叶变换(MDCFT)估计线性调频信号(LFM)参数时,当变换序列的起止点没有与实际有效信号对齐时,其中心频率会出现偏移,导致错误估计。针对该问题,本文提出一种分段的MDCFT算法,该方法通过对未知起止时刻的序列进行等长的分段MDCFT,并结合各段之间的幅度频率关系,实现中心频率的准确估计。通过仿真证明了算法的有效性。     

Robust Channel Estimation and Multiuser Detection for MC–CDMA Systems Under Narrowband Interference

In this paper, we present a robust adaptive channel estimator and a robust multiuser detector for wireless multicarrier code-division multiple access (MC–CDMA) systems under narrowband interference (NBI). The conventional least-squares (LS) channel estimator performs poorly when narrowband interfering signals contaminate the multicarrier systems. A new weighted recursive least M-estimate (WRLM) channel estimator is hence developed to estimate multipath fading channels in the presence of NBI. The new robust channel estimator resorts to M-estimate and weighted least-squares (WLS) techniques. Simulations show that the WRLM channel estimator offers substantial performance gain over conventional recursive least-squares (RLS), recursive least M-estimate (RLM) and weighted RLS (WRLS) channel estimators under NBI. With the estimated channel coefficients, a robust multiuser detector is proposed to jointly suppress multiple access interference (MAI) and NBI. The performance of the linear decorrelator will degrade substantially in the presence of NBI. A weighted least M-estimate (WLM) algorithm is therefore developed to combat the NBI. The WLM multiuser detector is also based on the weighted M-estimate concept. Numerical results show that the proposed WLM multiuser detector significantly outperforms over the conventional linear decorrelator, the robust decorrelator with M-estimate and the WLS detector under NBI.

坦克底盘与火炮匹配性评价平台研究

建立了坦克底盘与火炮匹配性评价的理论模型,应用虚拟样机技术和动力学软件ADAMS分析了坦克底盘与火炮参数化动力学模型,得出匹配性评价动态参数。以获得的评价参数为基础,使用SOLSERVER作为数据库开发平台,通过建立完整的火炮和坦克底盘的数据库结构,以VC^＋＋．NET作为编程工具,在平台内实现了匹配性评价的数学模型。     

Performances comparison of pulse-pair and 2-step prediction algorithms for the doppler spectrum estimation

In this work we use real data provided by terminal pulse Doppler radar (WSR-88D) echoes to estimate the windshear hazards disastrous for the aircraft takeoffs and landings. Briefly two different methods are used to estimate the received Doppler moments. The second central moment which is the variance of the wind speed is called width or shear. A first method is in the time domain and also called pulse-pair, while the second is in the frequency domain. The main aim of this study is a performances comparison of results provided by the two mentioned methods and assumes that the power spectrums of the received signals are approached with the Gaussian shape.     

一种WCDMA系统下行信道频偏估计算法及其性能分析

文章在深入研究WCDMA下行链路的信道结构及接收信号处理流程基础上,提出了一种在Rake接收机中,通过对P-CPICH（主公共导频信道）序列两次相关检测实现频偏估计的算法;同时,对该算法主要性能指标进行了分析及仿真,验证了算法的可行性。     

基WMSA信道估计技术的WCDMA上行链路性能分析

本文对用控制信道中的导频符号,有杉多时隙加权平均信道估计技术的ＷＣＤＭＡ上行链路进行了性能仿真研究。仿真结果表明,参与信道估计的时隙数目、加权系数的选取应针对不同的信道衰落环境。结合仿真结果,讨论分析了前向纠划、ＲＡＫＥ接收机的指峰数及信道中可分解路径的平均功率之差对ＷＣＤＭＡ上行链路性能的影响。     

Direction finding using data-supported optimization

A novel data-supported optimization technique for maximum likelihood (ML) direction-of-arrival estimation is proposed. The essence of our approach is to optimize the likelihood function at certaindata-supported points obtained by a resampled root-MUSIC procedure. These points are shown to comprise a small but representative subset of all possible searching points and contain enough information for solving the ML problem.This work was supported in part by grants from the National Sciences and Engineering Research Council of Canada (NSERC), Ministry of Energy, Science and Technology (MEST) of Ontario, Communications and Information Technology Ontario (CITO), and by the Senior Individual Grant Program of the Swedish Foundation for Strategic Research.