Channel estimation and interference suppression for uplink CDMA mobile communication systems

Wireless communications for mobile telephone and data transmission is currently undergoing very rapid development. Code division multiple‐access (CDMA) implemented with direct sequence spread spectrum signaling is among the most promising multiplexing technologies for cellular telecommunications services. In this paper, jointly period inserted pilot symbols assisted recursive (PIPSAR) channel estimation and interference suppression techniques are proposed for uplink CDMA mobile communication systems. The uplink CDMA mobile communication system model is described in the form of space‐time domain through antenna array and multipath expression. Interference suppression is achieved by using adaptive minimum mean squared error (MMSE) digital filters that span several successive received chip oversampling vectors of a symbol interval. PIPSAR techniques are used to estimate channel parameters. The correlation between the successive periods is considered to further improve the performance of the proposed scheme. Analysis and simulations are used to evaluate the performance of the proposed scheme. Copyright © 2004 John Wiley & Sons, Ltd.     

Improved low-distortion sigma-delta ADC with DWA for WLAN standards

An improved low distortion sigma-delta ADC(analog-to-digital converter) for wireless local area network standards is presented.A feed-forward MASH 2-2 multi-bit cascaded sigma-delta ADC is adopted;however,this work shows a much better performance than the ADCs which have been presented to date by adding a feedback factor in the second stage to improve the performance of the in-band SNDR(signal to noise and distortion ratio),using 4-bit ADCs in both stages to minimize the quantization noise.Data weighted ...     

J2EE架构下的移动智能网业务管理系统

首先对移动智能网中目前的业务管理系统的组成及各部分的功能进行了说明,并指出其缺陷,然后给出了基于J2EE(Java2PlatformEnterpriseEdition)架构下的移动智能网业务管理系统的设计和实现,并讨论了其优缺点。     

Effect of wafer thinning methods towards fracture strength and topography of silicon die

This paper characterizes die damage resulting from various wafer thinning processes. Die fracture strength is measured using ball breaker test with respect to die surface finish. Further study on surface roughness and topography of each surface finish is obtained by atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques. Stress relief process with 25 μm removal is able to strengthen 100 μm wafer by 20.4% using chemical wet etch and 75 μm wafer by 36.4% with plasma etch. Relatively, plasma etching shows higher fracture strength and flexibility compared to chemical wet etch. This is due to topography of the finished surface of plasma etch is smoother and rounded, leading to a reduced stress concentration, hence improved fracture strength.     

槽式DSG太阳能热发电集热管传热特性探讨

本文运用能量守恒的方法建立了集热管一维模型,分析了集热管在不同工况下的集热效率,同时建立二维模型给出了集热管出口温度和出口干度的计算方法,分析了24米长集热管在不同工况下的出口温度和干度,为今后建立槽式DSG太阳能热集热发电站提供参考意见。     

10Gbit/s高T0无制冷分布反馈激光器

与折射率耦合分布的分布反馈（DFB）激光器相比,不管界面反射率是多少,增益耦合DFB激光器都能稳定地单纵模工作,而且具有高速、低啁啾的特性．本课题组用AlGaInAs/InP材料,采用增益耦合DFB结构,进行了单纵模激光器研发,并对器件特性进行了测试分析．     

Rate adaptive resource allocation in orthogonal frequency division multiple access system using multi‐objective immune algorithm

Rate adaptive downlink resource allocation in orthogonal frequency division multiple access system is a constraint optimization problem, which is to maximize the minimum data rate of the user subject to constraint that total power cannot exceed a given value. How to handle the constraint is a key issue for constrained optimization problem. Different with the available schemes on constraint handling, the proposed algorithm converts the constraint into an objective. Then, the resource allocation is combined into a multi‐objective optimization problem. An improved multi‐objective optimization algorithm based on artificial immune system is proposed to solve it. The simulation results show that, compared with previous schemes, the proposed algorithm performs remarkable improvement in sum capacity. Copyright © 2013 John Wiley & Sons, Ltd.     

DATA PREPROCESSING AND RE KERNEL CLUSTERING FOR LETTER

Many classifiers and methods are proposed to deal with letter recognition problem. Among them, clustering is a widely used method. But only one time for clustering is not adequately. Here, we adopt data preprocessing and a re kernel clustering method to tackle the letter recognition problem. In order to validate effectiveness and efficiency of proposed method, we introduce re kernel clustering into Kernel Nearest Neighbor classification （KNN）, Radial Basis Function Neural Network （RBFNN）, and Support Vector Machine （SVM）. Furthermore, we compare the difference between re kernel clustering and one time kernel clustering which is denoted as kernel clustering for short. Experimental results validate that re kernel clustering forms fewer and more feasible kernels and attain higher classification accuracy.     

基于EIB的融合组网技术在智能家居中的应用

介绍智能家居系统中的常用组网技术,分析智能家居系统的实际需求,然后结合各类组网技术的适用性,提出一种以EIB为基础,同时融合IrDA和Wi-Fi技术的智能家居系统组网技术,并在上海市长宁区某街道的一个智能家居体验点中进行应用。该组网技术兼顾满足了智能家居系统高可靠性、高稳定性以及高速性的需求,具有一定的应用前景。