CDMA网络规划中的反向链路小区覆盖

反向链路小区覆盖是ＣＤＭＡ网络规划的关键部分,文章首先分析了实现反向链路小区覆盖的基本理论,然后提出三种解决方案。     

TD-SCDMA系统终端的小区初搜过程研究

文章在介绍TD-SCDMA系统协议栈结构的基础上,着重研究了TD-SCDMA系统终端的小区初搜过程,包括对小区选择标准,小区初搜过程的描述及TD-SCDMA系统终端的小区初搜过程的简单实现。     

基于GSM小区覆盖系统的TD-SCDMA改造探讨

本文对基于GSM的小区覆盖系统进行TD-SCDMA改造的关键问题进行了分析,提出并简化了一系列工程设计时所需的参考数值。最后,结合四个工程实例对比,找到了一种BBU+RRU组成的小区覆盖策略,可为小区覆盖工程提供一定的参考。     

分布式虚拟小区网络及其反向链路容量分析

本文提出了一种新的无线系统结构:基于分布式天线的分布式虚拟小区网络.在新型无线系统结构里,虚拟小区可自主移动与改变面积,这有益于容量提高,给无线资源管理带来诸多方便;其次,在不考虑阴影效应和多径衰落的情况下,对虚拟小区的反向容量进行了理论计算分析,并与分布式天线系统进行了对比.理论分析证明,虚拟小区可以降低用户发射功率,从而减少多用户干扰,提高系统容量.     

高档小区TD-SCDMA室内覆盖解决方案

未来3G业务大多发生在室内,作为中高端用户的集中生活区域,高档小区的TD-SCDMA网络质量,更是运营商关注的重点。本文总结对比了各种高档小区的类型以及覆盖方案比较,并提出了包括室内室外协同优化、室内优化方案,为提高TD用户客户感知、改善网络质量提供了有益经验。     

EV-DO系统特点及反向链路控制算法的分析

EV-DO作为一种基于CDMA的高速数据传输技术，前向采用时分复用方式，反向采用与cdma2000 1x相同的码分多址方式。因为EV-DO的前向采用的是时分复用方式，所以基站的容量主要取决于系统的反向链路情况。EV-DO特有的反向链路媒体介入控制算法机制可以参与调整基站反向链路，以优化小区的反向链路情况。     

CDMA系统小区负荷分析

目前3G标准(WCDMA、cdma2000、TD-SCDMA)都基于CDMA技术,CDMA系统是自干扰受限系统,系统容量为“软容量”,即不是固定值,取决于网络中的干扰,有较大弹性,网络覆盖范围和服务质量与同时接受的用户数量之间有平衡和折中的关系。如果空中接口负荷增加过度,小区的覆盖面积就会低于预计值,已有连接的服务质量也无法保证。因此合理有效的呼叫接纳控制(CAC,calladmissioncontrol)对3G系统的稳定运行具有重要意义。在3G系统中,呼叫接纳控制是无线资源管理(RRM)的重要功能实体,用于判断资源分配请求是否被系统接受,目的是维护网络稳定,保…     

Rayleigh信道下的多小区下行链路性能分析

针对存在来自相邻蜂窝小区的同信道、不同功率信道干扰的单用户下行链路场景,分析了基站和用户均为单天线时的系统性能.系统模型为两个基站、两个用户,基站与用户均为单天线.在期望信号和干扰信号均为Rayleigh分布时,运用基于概率密度函数性能分析法推导了系统中断概率;基于瞬时信干噪比(SINR)的推导,并对瞬时误符号率(SER)取平均的方法推导了平均误符号率(ASER)的闭合表达式和用户的接收SINR的n阶矩;根据用户接收平均SINR的n阶矩表达式,推导并分析了用户接收平均SINR的衰落量(AF)性能.计算机仿真了在不同干扰功率下多小区系统的中断概率、ASER的性能以及AF性能.仿真结果表明:单小区和多小区系统的中断概率、ASER和AF的解析曲线均与数值仿真结果一致.系统性能随着干扰基站功率的降低而提升,系统性能随发送功率的增加增益明显.     

浅议CDMA蜂窝移动通信系统的小区容量

自从二十世纪七十年代出现蜂窝网通信以来，世界各地移动通信行业得到了迅猛的发展，而蜂窝网的技术本身也得到了长足的进步。就多址接人方式而言，二十世纪八十年代出现了时分多址(TDMA)数字蜂窝网，以GSM为代表的数字蜂窝移动通信系统在国内外已获得了广泛应用。二十世纪九十年代又出     

WLAN小区覆盖技术方案

宽带无线接入已成为接入领域的热点。本文阐述了利用WLAN技术来实现小区的无线覆盖，为小区家庭和SOHO用户提供宽带接入服务的技术实现方案。     

Multi-Service Coverage Analysis for CDMA Planning

In CDMA network planning,it's important to understand the characteristics of multi-services.A novelmethod for analyzing the coverage of mixed voice and packet data traffics is presented in this paper.Based upon GIS andMonte-Carlo simulation method,this method can provide more precise but less time-consuming analysis result than before.A practical analysis case using real geographic information and network parameters is applied to verify its performanceand find some useful solutions.Simulation results show that this coverage analysis method can provide helpful solution forthe radio networks planning.     

TD-SCDMA室内分布系统改造的研究

本文根据TD-SCDMA网络的技术特点,分析并提供了TD-SCDMA系统的引入对现有室内分布系统改造的各种要求,并根据要求,对室内分布系统的信源选择方案以及系统建设方案进行了探讨。     

Using Bandwidth-Space Partitioning to Improve Cell Coverage and Near-Far Unfair Access Problem in a Noise-Limited CDMA Cellular Network

This paper concerns CDMA cellular networks equipped with conventional matched filter receivers. For this type of cellular networks, two problems exist. One is the inverse relationship between the coverage and capacity, and the other one is the near-far unfair access problem. To resolve these two problems, a bandwidth-space partitioning technique is adopted. Several admission control schemes based on the bandwidth-space partitioning technique are proposed, and their performances are evaluated based on the simulation.Shih-Tsung Yang received his B.S. (1989) and M.S. (1991) degrees in electrical engineering from the National Taiwan University, and Ph.D. (1999) degree in electrical and computer engineering from University of Maryland, College Park.From 1999 to 2000, he was with SBC Technology Resourtces, Inc. where he was involved in the network architecture design for the ATM based networks. From November 2000 to May 2003, he was with Transilica/Microtune where he was involved in the design of Baseband and RF for the wireless communications. Since May 2003, Dr. Yang is now with Genesys Logic, Inc. where he is responsible for the baseband design of the WLAN and Ethernet.Dr. Yang’s research interests are in the area of Digital Communications, Communication networks and signal processing. E-mail: thomas.yang@genesyslogic.com.twAnthony Ephremides received his B.S. degree from the National Technical University of Athens (1967), and M.S. (1969) and Ph.D. (1971) degrees from Princeton University, all in Electrical Engineering. He has been at the University of Maryland since 1971, and currently holds a joint appointment as Professor in the Electrical Engineering Department and in the Institute of Systems Research (ISR) of which he is a founding member. He is co-founder of the NASA Center for Commercial Development of Space on Hybrid and Satellite Communications Networks established in 1991 at Maryland as an off-shoot of the ISR. He served as Co-Director of that Center from 1991 to 1994.He was a Visiting Professor in 1978 at the National Technical University in Athenas, Greece, and in 1979 at the EECS Department of the University of California, Berkeley, and at INRIA, France. During 1985-1986 he was on leave at MIT and ETH in Zurich, Switzerland. He was the General Chairman of the 1986 IEEE Conference on Decision and Control in Athens, Greece and of the 1991 IEEE International Symposium on Information Theory in Budapest, Hungary. He also organized two workshops on Information theory in 1984 (Hot Springs, VA) and in 1999 (Metsovo, Greece). He was the Technical Program Co-Chair of the IEEE INFOCOM in New York City in 1999 and of the IEEE International Symposium on Information theory in Sorrento, Italy in 2000. He has also been the Director of the Fairchild Scholars and Doctoral Fellows Program, an academic and research partnership program in Satellite Communications between Fairchild Industries and the University of Maryland. He won the IEEE Donald E. Fink Prize Paper Award (1992) and he was the first recipient of the Sigmobile Award of the ACM (Association of Computer Machinery) for contributions to wireless communications in 1997. He has been the President of the Information Theory Society of the IEEE (1987) and has served on its Board of Governors almost continuously from 1981 until the present. He was elected to the Board of Directors of the IEEE in 1989 and 1990. Dr. Ephremides has authored or co-authored over 100 technical journal papers and 300 technical conference presentations. He has also contributed chapters to several books and edited numerous special issues of scientific journals. He has also won awards from the Maryland Office of Technology Liaison for the commercialization of products and ideas stemming from his research. He has served on the Editorial Boards of the IEEE Transactions on Automatic Control, IEEE Transactions on Information theory, the Journal of Wireless Networks, and the International Journal of Satellite Communications.He has been the Dissertation Supervisor of over twenty Ph.D. students who now hold prominent positions in academia, industry, and research labs. He is the founder and President of Pontos, Inc., a Maryland company that provides technical consulting services, since 1980.Dr. Ephremides’ interests are in the areas of communication theory, communication systems and networks, queueing systems, signal processing, and satellite communications. His research has been continuously supported since 1971 by NSF, NASA, ONR, ARL, NRL, NSA, and Industry. E-mail: tony@eng.umd.edu     

CDMA移动通信网络交通干线覆盖与容量分析

在交通干线上提供连续覆盖的移动通信业务,将对整个CDMA网络的应用推广带来非常大的影响。以湖南省境内交通干线作为研究对象,从CDMA覆盖和容量这两个方面对交通干线CDMA移动通信网络的实现进行分析,建立相关话务模型,并得出了相应的建设策略。     

TD-SCDMA室内覆盖全面解决方案

大唐移动针对3G建设中室内业务增加带来的挑战,提出了基于TD-SCDMA技术的3G室内覆盖全面解决方案.该方案可以为TD-SCDMA网络的运营商提供一站式服务,能够使运营商在3G网络建设初期迅速地以低成本、高容量的网络开展室内区域的TD-SCDMA网络建设,从而在争夺用户市场上占得先机.     

TD-SCDMA和WCDMA系统以及HSDPA的容量覆盖分析

作为3G的增强型技术的HSDPA已经越来越受到重视,在WCDMA系统网络规划中HSDPA的规划方法研究的较多。由于TD-SCDMA标准出现较晚,对应其引入HSDPA后的规划还不太成熟。本文分别阐述了两系统的网络规划的基本方法,分析探讨了其中的异同,从而更好地指导下一步TD-SCDMA无线网络规划。     

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。     

An Uplink Short-Term Fading Prediction-Based Power Control Method for DS/CDMA Cellular Radio Systems

In previous research, a new multi-step SIR-based powercontrol, referred to as short-term fadingprediction-based (SFP-based) method, has been proposedfor DS/CDMA downlink power control. Simulation resultsshowed that the SFP method outperforms the originalmulti-step SIR-based power control. In this paper, wefurther investigate the behavior of the SFP methodapplied to uplink. Simulation results show that theSFP method still performs better than the originalmulti-step SIR-based method. Although the uplinkperformance is still poorer than the downlink usingSFP power control method instead of the originalmulti-step SIR-based method, the improvement amount ofSFP-based method compared to the multi-step SIR-basedmethod in uplink is larger than that in downlink.     

Forward Link Performance Analysis in CDMA Distributed Antenna Systems with Imperfect Channel Estimation

1　Introduction　The Distributed Antenna (DA) system has been proposedas a promising antenna architecture for the future wirelesscommunication systems[1~10].　In the DA systems, with remote antennas, the presentcellular structure is removed and cells are not divided geo graphically, but according to the user needs. That is, ac cording to the channel estimates computed via pilot signals,the Processing Node (PN) continuously measures the chan nels between the mobiles and the remote ante…