CDMA网络掉话故障分析

介绍了CDMA网络中的掉话机制,重点从前向干扰、覆盖不足、前反向链路不平衡、业务信道功率受限、接入和切换冲突等方面分析了CDMA网络中掉话的原因及其处理方法.     

CDMA系统中的掉话问题

由于手机掉话会直接影响用户的感知程度,所以掉话现象是网络运营商最为关注的指标问题。通过系统分析CDMA系统中的典型的掉话原因,归纳出了相应的优化思路和解决方法,对CDMA网络实际的优化工作具有一定的参考意义。     

CDMA网络掉话优化分析

文章主要对CDMA网络中的掉话理论进行了深入探讨,并通过实例阐述了CDMA掉话优化思路和方法,以提高CDMA网络优化效率。     

CDMA网络掉话原因分析

分析了接入与切换碰撞、前向长期干扰、前向短期干扰、前反向链路不平衡、长期覆盖不好、短期覆盖不好、业务信道功率受限等7种类型掉话事件的掉话原因，并总结形成了掉话原因分析模板，将实际测试中遇到的掉话事件和此模板进行比对以帮助分析掉话事件发生的原因。     

CDMA无线掉话原因分析

在评价CDMA系统性能时掉话率是一个很重要的标准．深刻了解CDMA系统的“掉话机制”以及掉话原因能帮助我们对网络出现的问题进行分析．提高优化的效率。     

CDMA网络掉话解决方法探讨

掉话率是评估CDMA系统性能的一项重要指标,通过网优路测,分析了弱覆盖、导频污染、软切换问题引起的几种典型掉话现象产生的原因,并提出网络优化解决思路,从而改善业务信道质量。     

浅析CDMA无线掉话的原因

文章就CDMA系统中由于无线原因造成掉话的几种情况进行了较为详尽的分析,揭示了CDMA系统中无线掉话的深层次问题。     

CDMA网络掉话问题分析及优化

解决CDMA掉话问题是网络优化的重点。通过一些掉话现象，详尽地剖析了产生掉话的原因及解决的办法。     

基于CDMA网络的掉话分析方法

文章基于对CDMA网络掉话基本原因的深入了解和分析,以及网络优化人员及时消除掉话现象的需要,提出了一种解决移动网络掉话问题的思路,给出了该思路的具体流程;最后针对城区路测图进行具体分析,找出了掉话原因并使问题得到了改善。     

CDMA掉话问题的全面分析

CDMA系统具有软切换、抗干扰等技术特点．号称不易掉话前提是系统设计及参数设置合理、覆盖充分、设备正常、外界无干扰．由于以上几个条件经常都不能完全满足因此CDMA系统确实存在不少掉话，文章根据3年来CDMA系统的运行维护和优化的实践经验和经典案例．对掉话问题进行了全面和系统的论述．为CDMA掉话分析提供了完整的具体思路。     

CDMA无线定位

CDMA无线位置服务是一项刚刚兴起的移动数据业务，国内目前尚无此项服务，在全球范围内也只有少数几个运营商开展了这项业务。详细介绍了目前主要的几种定位技术方案，并进行了比较，同时介绍了CDMA无线定位系统的结构及其定位信息的承载协议，还提出了两类定位信息传输系统实现方案。     

A Low Power Correlator for CDMA Wireless Systems

The complex valued matched filter correlators consume maximum power in the DS/SS CDMA receivers. These correlators accumulate 1024 samples lying in the range –7 to +7. This accumulation needs 3 data bits, 1 sign bit and 10 extra bits for overflow. Hence, the correlator can be implemented as a cascade of 4-bit full adder and a 10-bit incrementer. As a ripple carry adder (RCA) consumes the least power among all the existing adder architectures, we have implemented the 4-bit adder as a RCA. Previous incrementers were implemented as ripple counters. In this paper we propose a novel incrementer which is faster than a ripple counter based incrementer. Hence, it can be operated at a reduced voltage resulting in considerable power reduction. The incrementer is implemented using multiplexers, AND gates and TSPC registers. The ripple-counter correlator and the proposed incrementer correlator were laid out in MAGIC using 0.5 CMOS technology followed by power estimation using HSPICE. It is shown that the proposed architecture requires 50% less power than a ripple counter based design.     

Delay Analysis of Packet Scheduling with Multi-Users Diversity in Wireless CDMA Systems

There have been a number of studies that investigate efficient packet scheduling schemes to support quality of service of multiple real-time data users and to increase capacity of non-real-time users sharing a wireless channel. We consider the problem of scheduling transmissions of multiple data users sharing the same wireless channel so as to satisfy delay or throughput and present a general packet scheduling, called MBCS (Multi-users Best Channel Scheduling) which takes advantage of the multi-user diversity of a mobile wireless system. In this paper, a queuing model that represents radio resource management for supporting packet data services is developed for the purpose of evaluating the performance of wireless CDMA systems. Numerical results show that delay performance of the proposed scheduler is higher than that of the Single-user Best Channel Scheduler (SBCS) depending on the time-varying channel status.Sungkyung Kim is a Ph. D. student in the collage of information & Communications at University of Korea, Seoul, Korea. She received her B.S. and M.S. degree in electrical engineering from Korea University in 1999 and in 2001, respectively. From March 2001 to August 2004, she worked at the Electronics Telecommunications Research Institute, Daejeon, Korea, as a member of research engineer. Her research interests include MAC protocol, radio resource control, packet scheduling, and system performance evaluation at system level in wireless access networks.Chung Gu Kang received his B.S. degree in Electrical Engineering from the University of California, San Diego in 1987 and his M.S. and Ph.D. degrees both in Electrical and Computer Engineering from the University of California, Irvine, in 1989 and 1993, respectively. While working on his Ph.D. dissertation from June 1991 to May 1992, he also was with the Aerospace Corporation in El Segundo, California, as a part-time member of technical staff (MTS). After graduation in 1993, he joined Rockwell International in Anaheim, California, where he has been working on the signaling system no. 7 and other telecommunication systems development. Since March 1994, he has been with College of Information & Communications at the Korea University, Seoul, Republic of Korea, as a full professor. His research interests include next generation mobile radio communication system and broadband wireless networks, with special emphasis on physical layer/medium access control layer design and performance analysis. During the academic year of 2000, he has been a visiting scholar at Center for Wireless Communication and also a visiting professor at Department of Electrical & Computer Engineering in University of California at San Diego (UCSD). He is a member of IEEE COMSOC, IT, and VT, and a member of KICS and KITE.     

An Efficient Algorithm to Solve the Problem of Dropped Call in CDMA Cellular Systems

1 Introduction For any multi-user communication system, it is a big problem that the call drops out to the user and service provider. The propagation conditions required for a satisfactory communication can not always be met owing to irregularities in cel…     

An Efficient Algorithm to Solve the Problem of Dropped Call in CDMA Cellular Systems

In the mobile environment, the dropped calls can be resulted from shadowing and rapid signal loss. As the cells shrink to accommodate an increasingly large demand for services, the dropped-call recovery procedure will become more important over the air interface. But in the current protocols, the recovery procedure is too simple to demonstrate the procedure. In this paper, we present a Transparent Reconnection Procedure (TRP) which is an efficient algorithm that can be adapted easily to the benefit of decreased dropped calls. In the simulation of a typical cellular system, it is shown that there are fewer dropped calls using TRP compared to the conventional procedure. This benefit comes at the expense of a slight increase (less than percent 1) in blocked call percentage. It depends on some relevant system parameters, the values of which are decided by the operators accordingly.     

CDMA系统中半盲恒模算法的性能分析

本文对应用于CDMA上行链路多用户检测中半盲恒模算法的收敛性能、SIR性能和复杂度进行了深入研究。我们在无噪环境下分析了半盲恒模算法全局收敛的条件;通过算法SIR性能的分析,可知半盲算法可以获得更加优良的抵消MAI的能力;通过半盲恒模算法、盲恒模算法、解相关算法的复杂度比较,可知半盲恒模算法以略高于解相关算法复杂度的代价获得优于解相关算法和恒模算法的SIR性能和BER性能。     

一种用于CDMA系统的智能天线波束形成方法

在智能天线的实际应用中，波束形成所需的时间及其复杂度是决定其能否实施的主要因素。本文分析了CDMA通信系统的特点，提出了一种新的用于CDMA系统的波束形成方法。该方法带来的好处是放宽了对时间的要求和降低了系统的复杂度，权值的稳定性也得到了提高。该方法下的系统性能仿真结果表明，与全向天线相比，系统的信干比和误比特率得到很大改善。文章最后研究了不同参考信号下系统的性能，结果表明，在强干扰情况下，用判决信号作参考信号时系统性能将下降，应避免使用。     

浅谈CDMA网络优化

网络优化的目的是改善网络的通信质量。采用快速有效的网络优化方法,改善网络的性能和服务质量是移动运营商关注的主要问题之一。由于CDMA是干扰受限系统,因此CDMA网络的优化尤为重要。本文简要概述了CDMA无线网络优化的方法及相关措施,对网络优化的准备工作、数据分析以及优化办法进行了相关探讨。     

CDMA网络接入失败原因的分析

详细分析了CDMA移动台接入失败的原因，并提出了相应的解决措施，对CDMA无线网络的网络优化工作有一定的指导作用。