TD-SCDMA系统下行联合波束功控技术

TD-SCDMA系统最重要技术特征是智能天线技术。本文基于时延和角度扩散空间信道模型,提出了一种下行基站联合优化波束和发射功率的智能天线技术。     

CDMA蜂窝移动通信系统中的联合功率控制

功率控制技术是CDMA系统克服“远-近效应”,降低多址干扰、增大系统容量的一项关键技术.第三代移动通信系统对功率控制提出了新的研究课题.本文简要介绍了联合功率控制技术的基本概念,重点阐述了目前在多媒体CDMA系统中,联合功率控制与速率控制技术,与多用户检测技术,以及与自适应天线阵列处理技术的研究进展,并分析了目前研究中仍然存在的问题,最后指出了未来的研究方向.     

多业务CDMA系统中基于最大化流量的功率速率联合控制

功率控制技术是CDMA系统中减小多址干扰的一项关键技术。针对TDD-CDMA系统的多速率业务,提出了一种功率速率联合控制算法,速率控制保证不同业务的服务质量要求,通过线性优化过程获得最大化流量时的功率速率分配。仿真结果表明这一算法是一种近似的最优化功率速率联合控制方案,能够有效地提高系统的总容量,优化系统性能。     

一种CDMA蜂窝通信系统中的功率控制算法

功率控制是CDMA蜂窝通信系统的关键技术.本文给出一种部分补偿信干比的功率控制算法,可以提高系统的容量,改善系统性能.     

CDMA功率控制的MATLAB仿真

论文总结了CDMA通信系统功率控制的目的和方法,重点介绍了基于信噪比的功率控制算法,最后利用MATLAB工具,对开闭环结合的功率控制方法进行了仿真,给出了实验结果。     

CDMA系统的功率控制技术

CDMA系统由于频率复用,以及无线信道的衰落等原因,存在"边缘效应"和"远近效应",降低干扰可以直接增加CDMA系统的通信容量,功率控制技术即是一种有效的方法.本文详细阐述了CDMA系统中功率控制的原理,算法及存在的问题和相关解决方法.     

CDMA2000中的功率控制及容量仿真

在码分多址(CDMA)系统中,在不影响通话质量的前提下,要使得系统容量最大化需要采用功率控制技术.功率控制的主要方法是通过降低每个移动台和基站的发射功率使得系统中干扰最小化.在建立模型的基础上,文章分别对单小区和多小区CDMA系统的系统容量进行了理论推导,并采用19个小区的仿真模型对系统容量进行了仿真.在将仿真得出的结果与理论推导值比较后,得出结论:功率控制的偏差直接导致系统容量的下降,因此研究出更好的功率控制算法对于提高系统容量至关重要.     

认知MIMO系统中波束成形和功率的联合控制博弈算法

针对认知MIMO系统中波束成形和功率的联合优化问题,建立了非合作可分离对策联合博弈模型,提出了新的代价函数,根据KT条件证明了该模型中的各个子博弈均存在最优纳什均衡,从而得到联合博弈存在最优纳什均衡的结论,并提出了新的交替迭代算法。仿真结果表明,该算法有较快的收敛速度;同时,在动态环境下,算法也能达到最优纳什均衡,具有较好的稳定性。     

关于CDMA蜂窝系统中功率控制的分析

本文就ＣＤＭＡ蜂窝系统中的功率控制问题进行了讨论,其中包括功率控制误差的考虑以及功率控制源的选择,在以往的分析中,常常只考虑基于距离的功率,选择,本文引入了对实际环境下基于导频功率的选择考虑,给出了两种方法的比较,数值计算结果显示后者在系统容量上有一定的改善。     

Optimum Uplink Power/Rate Control for Minimum Delay in CDMA Networks

We derive a new joint power and rate control rule with which we can minimize the mean transmission delay in CDMA networks for a given mean transmission power. We show that it is optimal to respectively control the power inverse‐linearly and the rate linearly to the square root of channel gain while maintaining the signal‐to‐interference ratio at a constant. We also show that the proposed joint power/rate control rule achieves excellent performance results in terms of the probability of the instantaneous delay being within a target delay against one‐dimensional control schemes.     

Joint Optimization of User Set Selection and Transmit Power Allocation for Orthogonal Random Beamforming in Multiuser MIMO Systems

When the number of users is finite, the performance improvement of the orthogonal random beamforming (ORBF) scheme is limited in high signal‐to‐noise ratio regions. In this paper, to improve the performance of the ORBF scheme, the user set and transmit power allocation are jointly determined to maximize sum rate under the total transmit power constraint. First, the transmit power allocation problem is expressed as a function of a given user set. Based on this expression, the optimal user set with the maximum sum rate is determined. The suboptimal procedure is also presented to reduce the computational complexity, which separates the user set selection procedure and transmit power allocation procedure.     

CDMA卫星通信系统功率控制研究

文章从卫星通信系统的功率控制原理入手,提出了一种适合CDMA卫星通信系统的功率控制方法;给出了精准的功率控制时的系统容量,通过推导给出的中断概率公式和例举的CDMA卫星通信系统实际数据,将功率控制误差对于系统容量的影响进行了仿真.仿真结果表明,当标准方差不断增大,系统的中断概率增大,系统容量随之显著减小;而采用精准的功率控制技术,可以有效改善系统性能.     

CDMA蜂窝集群前向功率控制技术的研究

本文对基于CDMA的集群通信系统的功率控制进行了初步的研究。针对集群通信的特点，本文提出了CDMA共享信道的概念和集中式前向功率控制技术，并进行相应的仿真。结果表明，该技术很好地解决了在CDMA蜂窝通信中实现集群功能的功率控制问题，大大增加了系统的容量。     

Essential Considerations in Implementing the Smart Antenna System for Downlink Beamforming

This paper addresses some essential problems that have to be taken into consideration in implementing the smart antenna base station (SABS) for downlink beamforming. In order to provide proper downlink beamforming as well as uplink beamforming, a pragmatic procedure of automatic calibration is proposed. Through the experimental test, we confirm that the proposed calibration technique has eliminated the problem of the phase differences of the signal path associated with each antenna. Also, in this paper, we first analyze the multipath condition under which the auxiliary pilot becomes indispensable for detecting the data transmitted on the data channel and what happens if the auxiliary pilot is not available. Then, the performance of the downlink beamforming utilizing the auxiliary pilot is analyzed through the computer simulations. Finally, we present a comparison of downlink communications to uplink ones in terms of throughputs available at each of uplink and downlink communications. Weon-Cheol Lee received the B.S, M.S, and Ph.D. degree in Electronic Communication Engineering from Hanyang University, Korea, in 1992, 1994, 2005, respectively. From 1994 to 2000, he was with LG Electronic Inc., where he had worked for developing the digital VCR, digital cable modem, digital TV. Since 2001, he has been a professor with department of information and communications, Yong-in Songdam College, Korea. His research interests include smart antennas, mobile communications beyond the third generation, digital broadcasting technology, and communication signal processing. Dr. Lee also received the Best Research Paper Award and Excellent Research Engineer Award from LG Electronics, respectively. Seungwon Choireceived the BS degree from Hanyang University, Seoul, Korea, and the M.S. degree from Seoul National University, Korea, 1980 and 1982, respectively, both in electronics engineering, the MS degree (computer engineering) in 1985, and the PhD degree (electrical engineering), in 1988, both from Syracuse University, Syracuse, NY. From 1988 to 1989 he was with the Department of Electrical and Computer Engineering of Syracuse University, Syracuse, NY, as an Assistant Professor. In 1989 he joined the Electronics and Telecommunications Research Institute, Daejeon, Korea. From 1990 to 1992 he was with the Communications Research Laboratory, Tokyo, Japan, as a Science and Technology Agency fellow, developing the adaptive antenna array systems and adaptive equalizing filters. He joined Hanyang University, Seoul, Korea, in 1992 as an assistant professor. He is a professor in the School of Electrical and Computer Engineering of Hanyang University. Since 2003, Dr. Choi has been serving as a Vice Chairman and the representative of the ITU region 3 for SDR (Software Defined Radio) Forum and as a Director of the HY-SDR Research Center, MIC, Korea. His research interests include digital communications and adaptive signal processing with a recent focus on the implementation of the smart antenna systems for both mobile communication systems and wireless data systems. Jae-Moung Kim received the BS degree from Hanyang University, Korea in 1974, the MSEE degree from University of Southern California, USA in 1981, and the PhD degree from Yonsei University, Korea in 1987. He was a Vice President of Radio {&} Broadcasting Technology Laboratory and Director of Satellite Communication System Department at Electronics and Telecommunications Research Institute (ETRI) from September 1982 to March 2003. Since April of 2003, he has been a Professor in the Graduate School of Information Technology and Telecommunications, Inha University. He is a board member of directors of Korean Institute of Communication Science (KICS), a Vice President of Korea Society of Broadcast Engineers (KOSBE) and a senior member of IEEE. His research background is telecommunication systems modeling and performance analysis of broadband wireless access systems, mobile communications, satellite communications and broadcasting transmission technologies.     

频率选择性衰落信道下长扩频序列CDMA 系统的盲波束成形

本文提出一种适用于频率选择性衰落信道下长扩频序列CDMA系统，基于DMMSE准则的盲波束成形方案。该方案反频率选择性衰落信道分解成若干个非频率选择性衰落子信道，不需要训练符号开销，回避跟踪衰落信道参数，以所需用户的扩频序列作为永久性训练序列。仿真结果验证了其抵抗远近效应、抑制多址干扰的能力。     

CDMA系统中一种新的基于MMSE多用户检测的自适应功率控制算法

功率控制技术是CDMA通信系统中克服“远一近效应”，降低多址干扰、增大系统容量的一项关键技术。第三代移动通信系统对功率控制提出了新的研究课题。在本文提出CDMA系统中一种新的白适应功率控制和MMSE多用户检测的联合优化的算法，仿真结果表明，这种新的联合优化算法对提高系统容量，改善系统性能有很大的作用。     

Optimal Multi-User Interference Balancing Using Transmit Beamforming

Wireless Personal Communications - We study the problem of non-orthogonal spatial multiplexing under hard fairness constraints, assuming that the transmitter is equipped with multiple antennas and...     

A Novel Space-time Spreading Transmit Diversity Scheme for Wireless CDMA System

1　Introduction　Thefundamentalchallenge,whichmakesreliablewirelesstransmissiondifficult,isthetime varyingmulti pathfading .Theoretically ,themosteffectivetechniqueformitigatingmulti pathfadinginawire lesschannelistransmitterpowercontrol.ButinCDMAsystems,powercontrolislimitedbythetransmitterdynamicrangeandthenear fareffect.Diversityisanefficientandpracticaltechniquetocombattime varyingmulti pathfading .Andanten nadiversityiswidelyappliedtoreducetheeffectofmulti pathfading .Theclassicalappro…     

Simulation of Power Control and Diversity of Cellular CDMA

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非完备功控CDMA无线网络上行准入控制算法及性能分析

本文研究了非完备功控宽带CDMA无线网络上行准入控制问题。首先为非完备功控CDMA网络上行链路建立了系统模型，然后设计相应的准入控制算法，其中无线资源被划分为供各类用户专用的部分和在各类用户之间共享的部分。为了利用非实时用户可以容忍延时的特点，又引入了队列结构以降低阻塞率。通过对算法进行Markov分析，从理论上计算了用户阻塞率和平均吞吐率性能。仿真结果验证了理论模型的正确性。