CDMA网络高速交通干线覆盖专题研究

本文通过对特殊地形条件下全向站和定向站的覆盖研究,得出了在丘陵地带用全向站做道路覆盖同样能达到定向站效果的结论。另外,提出了用室外站解决隧道覆盖的方式以减小协调难度和减少投资,采用紧凑型机房及交流RRU以减小建站难度、减少投资、加快网络建设进度等建议。     

GSM网络交通干线覆盖

本文介绍了GSM网络交通干线的覆盖特性，提出了几种经济实用的良好覆盖方式，最后列举了几个典型的工程实例。     

CDMA山区及交通干线覆盖方案

结合不同的用户分布和山区丘陵地形的特点进行站址选择和设备选型分析,通过系统仿真来比较高山站与平地站的覆盖范围,综合考虑覆盖目标、建设成本和投资收益对二者进行取舍.     

TD-SCDMA系统高速交通干线覆盖解决方案

本文结合高速交通干线区域覆盖特点,通过对TD—SCDMA系统高速移动通信支持能力的分析,得出了影响TD—SCDMA系统高速移动通信的基本因素,并给出了包括物理层解决技术、无线资源管理策略以及网络覆盖方案等方面的TD—SCDMA系统高速交通干线覆盖的解决方案,经过实际测试,该解决方案完全满足了TD—SCDMA大规模建网对高速交通干线的覆盖需求。     

CDMA蜂窝移动通信系统的容量分析

本文首先导出了容量公式，然后分析了影响容量的若干因素和扇区化问题，最后对ＣＤＭＡ系统和ＧＳＭ系统的容量进行了分析。     

CDMA蜂窝系统反向链的话务容量分析

随着通信技术的发展，ＣＤＭＡ通信体制的潜在技术优势正在得到发掘。本文首先介绍了在ＣＤＭＡ蜂窝系统中呼叫“软阻塞”问题，然后通过严密的数学推导，对功率受控的ＣＤＭＡ蜂窝系统单个扇区反向链的话务容量作了详细分析，其结果具有一定的参考价值．     

三值CDMA移动通信系统容量分析

从编码理论和话务理论出发 ,分析了三值CDMA移动通信系统的系统容量。证明在信息传输速率一致的条件下 ,三值系统的无线容量约为二值系统的log2 3(约 1 6 )倍 ;在码元传输速率一致的条件下 ,三值系统的服务等级更高。可见 ,三值CDMA系统为解决现有移动通信系统容量不足的问题开辟了新的途径。     

CDMA覆盖容量优化策略

随着我国手机用户骤增和通信网络的庞大，为用户提供优质的通信服务已成为各个运营商工作的重中之重。为此，一大批从事网络优化的工程技术人员日夜奋战在第一线，以自己的艰辛劳动和聪明才智努力为用户服务，同时也积累了许多宝贵的经验。为了不断提高我国网络优化工作的水平，本刊特开设“网络优化”栏目，为广大工程技术人员提供一个交流的平台。欢迎大家踊跃投稿（投稿信箱：dcw@dcw．org．cn）。     

高速交通干线WCDMA网络规划方法

介绍高速交通干线规划特点,分析穿连损耗、天线设置、多普勒频移、小区切换、LAC区规划、频率规划及公网与专网对高速交通干线WCDMA网络规划的影响及规划策略,最后从共建共享的角度对高速交通干线WCDMA网络提出了建议.     

CDMA低轨道卫星移动通信系统的容量分析

通过对低轨道卫星移动通信系统的上行链路和下行链路的分析,定性介绍系统在不同状态下的容量关系     

宽频带脊波导±45°移相器的原理和设计

Ｃ波段收、发各８００ＭＨｚ带宽频谱复用馈源网络代表着当今国际卫星通信天线技术发展的最高水平，其核心部件之一是８００ＭＨｚ带宽４ＧＨｚ圆极化移相器。本文介绍一种新颖的脊波导±４５°移相器，并采用周期性结构理论、微扰理论和等效比拟法，在国际上首次对这种膜片周期加载型脊波导移相器进行了理论分析；并给出了分析、设计程序。实验表明，理论与实际比较吻合。     

宽窄合用CDMA卫星移动通信系统容量的研究

本文分析了宽窄合用CDMA卫星移动通信系统中宽带CDMA信号和窄带CDMA信号之间的相互干扰,提出了最佳的宽窄合用频谱配置方案.研究表明宽窄CDMA信号适当合用后,卫星移动通信系统容量能够大幅度提高.     

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     

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.     

CDMA通信卫星系统容量分析

对基于码分多址(CDMA)体制的通信卫星系统及其容量进行了分析,从系统的角度,提出了CDMA体制的通信卫星系统容量的数学模型。定量分析了用户数量与系统的扩频增益、抗干扰能力指标、卫星转发器饱和功率等的关系,容量分析的结果可供人们在选择和设计通信卫星系统时参考。     

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。     

CDMA移动通信网络的优化

首先介绍了网络优化的基本知识,然后以一个边远城镇的CDMA网络为例,通过比较,确定利用光纤直放站形式对网络进行优化的方案,并对其中主要技术指标进行了分析和计算.     

无线网络中的业务行为及业务容量——概念、模型及发展

针对无线通信网络,分析了现有国内外研究中对业务的几种不同概念的理解,综述了目前国内外在业务建模研究方面所获得的主要成果,并对当前的业务行为模型特点进行了分类和评价。同时总结了目前研究产业界中常见的无线网络中的多种不同的容量概念。最后从已有的容量概念出发,结合能够更加精确刻画不同业务特性的业务行为模型,提出适用于无线网络系统的业务容量的全新概念,为发展面向业务行为的无线网络设计及进一步提高无线传输系统的效率打下了坚实的基础。     

Performance Analysis of Trunk Network for Inter-MSC Soft Handoffs in CDMA Cellular Communication Systems

The soft handoffs between two adjacent MSC's should be employed to support the calls requesting handoffs to an MSC while minimizing the undesirable “ping pong” phenomenon of back-and-forth handoffsbetween two adjacent cells in conventional hard handoffs. In this paper, the soft handoff scheme between two MSC's is considered using the trunk between the packet routers for the two MSC's. The trunk network is proposed to support the inter-MSC soft handoff scheme in the service area with many MSC's. The probability that a°soft handoff to an adjacent MSC will be blocked due to the shortage of the trunk capacity is derived.