Joint Transmit Beamforming and Power Control for CDMA System

1　Introduction　Power control and beamforming are two main methods toreduce interference in CDMA cellular communication sys tem. In power control, the transmitters powers are constant ly adjusted when the instantaneous SIR is not equal to targetSIR, so that the quality of weak links is improved. Base sta tion equipped with antenna arrays may adjust their beam pat terns so that they have maximum gain towards the directionsof target mobiles and minimum gain towards the other direc tio…     

Audio source separation: solutions and problems

The problem of separating out a number of audio sources observed from an array of microphones in a real room environment has received a great deal of attention in the past decade. While there are now a number of workable methods that can even deal with relatively high reverberation (IEEE Trans Audio Speech Process, 2003; 11 :489–497), a number of interesting problems still remain. In this paper, the authors review the methods based around independent component analysis, discussing the various choices available in algorithm design. We then explore the issue of sensitivity to speaker movement which appears to impose fundamental limitations on BSS performance. Copyright © 2004 John Wiley & Sons, Ltd.     

俄罗斯感应测井仪与国产双感应测井仪的对比及其应用

2004年中国石油测井长庆事业部从俄罗斯引进了2套H-IKZ-2型感应测井仪,为了配合该仪器在长庆油田的推广,对其测井资料进行了初步的分析研究。采用交会图技术将俄罗斯感应测井仪的深探测(IR4A)电阻率与BSJ801双感应八侧向测井仪的深感应(R ILD)电阻率在不同电阻率储层中的响应值进行了对比,找出了二者之间的差异;在处理参数相同的情况下,将2种深探测电阻率计算的含水饱和度与岩心分析含水饱和度进行了对比和分析;最后,以实例的形式分析了孔隙度、渗透率等储层参数对俄罗斯感应测井仪的影响及其应用效果,总结出了初步的定性解释方法。     

Space-Time Coded Beamforming for DS CDMA Downlink

1　Introduction　 In 3G mobile system, Code Division Multiple Access(CDMA) is a promising multiple access techniques. It iswell know that BeamFormin ( BF), Space Time Coding(STC) and Multiuser Detection(MUD) techniques in CDMAsystem can effectively resist Multi Path Interference (MPI),MAI and near far effects. So the system capacity will be im proved greatly by employing these techniques[1,2,8]. In Ref.[3] introduces Water Filling(WF) theory into STC to assignth…     

Service function chain embedding algorithm with wireless multicast in mobile edge computing network

To resolve the excessive system overhead and serious traffic congestion in user-oriented service function chain (SFC) embedding in mobile edge computing (MEC) networks,a content-oriented joint wireless multicast and SFC embedding algorithm was proposed for the multi-base station and multi-user edge networks with MEC servers.By involving four kinds of system overhead,including service flow,server function sustaining power,server function service power and wireless transmission power,an optimization model was proposed to jointly design SFC embedding with multicast beamforming.Firstly,with Lagrangian dual decomposition,the problem was decoupled into two independent subproblems,namely,SFC embedding and multicast beamforming.Secondly,with the L_p norm penalty term-based successive convex approximation algorithm,the integer programming-based SFC embedding problem was relaxed to an equivalent linear programming one.Finally,the non-convex beamforming optimization problem was transformed into a series of convex ones via the path following technique.Simulation results revealed that the proposed algorithm has good convergence,and is superior to both the optimal SFC embedding with unicasting and random SFC embedding with multicasting in terms of system overhead.     

滤波求和恒定束宽波束形成器设计

文章在深入分析连续阵的恒定束宽波束形成理论基础上，将阵元权系数等效为两级滤波器，第一级只该与基阵的孔径分布有关，第二级只与基阵的维数有关，给出了滤波器的设计方法。通过时域的滤波求和实现恒定束宽波束形成，避免了频域分解，降低了运算量。该方法可用于一维、二维和三维情况，并且适用于任意带宽。基于非均匀线阵的计算机仿真表明该方法的恒定束宽效果是令人满意的。     

Key payload technologies for future satellite personal communications: A European perspective

This paper deals with satellite payload architectures adequate for the provision of universal mobile telecommunication services (UMTS) by medium altitude earth and geostationary orbit (MEO and GEO) satellites. The payload concept introduced is based on a transparent transponder with onboard digital signal processing (DSP) operations and digital beamforming at the traffic carrier level (narrowband beamforming). The emphasis of the paper is on key design aspects and technology considerations of the payload processor unit (PPU), which includes multiplexing/demultiplexing and digital beamforming operations, and on the antenna and RF signal handling subsystems. For completeness, a review on the European digital technology is also presented. The development of such a payload architecture is in line with present and planned activities of the European Space Agency (ESA) for MEO and GEO orbit systems, which are also implicitly discussed in the paper.     

M盆地淡水地层油层电性标准研究

M盆地 L区地层水为淡水类型 ,各井随埋深的不同及钻井泥浆性能的不同 ,油、水电性识别极为困难。油、水层二者间的各种电阻率的交叉范围很大 ,应用经典的确定某一电阻率值的方法或 RL Ld- RMSF L等关系不可能建立其有效的图版。自然电位曲线是主要反映泥浆滤液与地层水关系的电测曲线 ,自然电位异常幅度值ΔVSP亦与地层电阻率有关。根据自然电位电性原理 ,对 M盆地 L区试油层的 RLL d-ΔVSP的关系进行了研究。研究表明 ,油、水层在 RL Ld-ΔVSP图版上具有明显的界面 ,利用界面方程可对 M盆地 L区油、水层进行有效的判别 ,具有极为重要的应用价值     

稀布阵综合脉冲孔径雷达的研究与试验

稀布阵综合脉冲孔径雷达是一种先进的米波雷达。本文介绍了其基本概念、几个研究问题和一些试验结果。     

数字滤波技术在电阻率测井仪器中的应用探讨

以微球测井仪为例建立了对采集数据作数字滤波处理的数学模型,并进行了仿真研究.其结果表明,与传统模拟处理方法相比,数字滤波器不仅能有效减少硬件,而且更因其阶数高、幅频特性更理想、无温度漂移、处理精度和可靠性较高,从而提高了数据处理的质量,其处理速度也能够满足测井实时性的要求.此方法对其它电阻率仪器也可适用.