CDMA蜂窝移动通信系统的软切换

介绍了ＣＤＭＡ蜂窝系统采用的越区切换方式，详细分析软切换的原理及实现，突出了软切换在小区制通信体制中的作用。     

蜂窝移动通信系统的中的切换

切换是蜂窝移动通信系统的中地一项关系技术。本文介绍了蜂窝移动通信系统 中不同的切换方案，分析了各种方案的优缺点，同时，着重讨论了ＣＤＭＡ蜂窝系统中的软件切换方案。     

蜂窝移动通信系统中的切换

切换是蜂窝移动通信系统中的一项关键技术。本文介绍了蜂窝移动通信系统中不同的切换方案，分析了各种方案的优缺点，同时，着重讨论了CDMA蜂窝系统中的软切换方案。     

浅谈GSM和CDMA系统中的频道切换技术

切换技术是ＧＳＭ和ＣＤＭＡ系统中保证用户通信质量的一个重要手段。本文围绕这两种系统切换技术进行论述，包括越区切换，越局切换，并介绍了ＣＤＭＡ软切换技术的优越性及其切换原理。     

GSM蜂窝区移动通信系统越区切换

ＧＳＭ蜂窝区移动通信系统越区切换孙玉望１概述越区切换就是移动台从当前的服务小区（ＢＴＳ）切换到另一个小区的过程。如果当前服务小区信道质量很坏，即误码率过高，或接收信号电平太低，或功率开销太大，就应考虑切换。如果从当前小区与新小区之间是否同步来考虑，越...     

蜂窝移动通信系统新的呼叫和切换

应用蜂窝移动通信系统的非优先模式（NPS）理论模型，通过Markov链，对蜂窝移动通信系统新的呼叫与切换进行仿真分析。最后，在移动蜂窝有扇区和无扇区的条件下分析移动台在低速移动下对切换的影响。     

蜂窝移动通信系统中软硬切换衰落余量分析

基于具有对数正态阴影衰落的两小区系统模型,分析了采用不同切换技术时,为满足一定的中断率系统所要求的衰落余量,并给出了详细的推导过程。仿真结果表明,在要求中断概率相同的情况下,具有有限滞后电平的硬切换所要求的衰落余量大于软切换所要求的衰落余量而小于孤立小区硬切换所要求的衰落余量,并且滞后电平越小,所需要的衰落余量就越小。     

Outage Performance with Handover Triggering in Cellular Mobile Networks

An approach to performance evaluation of cellular mobile networksis proposed, which includes the behavior of handover algorithmsin the computation of outage probability.In a general system scenario, with a central cluster and interferingbase stations, the average outage probability is computed along a trip of themobile terminal that involves crossing the boundary between adjacent cells.The effects of correlated co-channel interferersare accounted for in the computationof outage probability, as well as in the dynamics of a relative signalstrengthhandover algorithm.Numerical results are provided and discussed as obtained over a wide rangeof values of system parameters, namely cluster size and channel parameters.Trade-off curves are shown in terms of outage probability and cross-overpoint versus the average number of handovers, and possible design criteriaare outlined.It is also seen that the local outage analysis (without handover triggering)can be referred to as a lower performance bound in cases of practicalinterest.     

A Novel Modelling Technique for Tracing Mobile Users in a Cellular Mobile Communication System

Mobility of users in a cellular mobile communication system has been formulated mathematically under generalized conditions. Based on this model a computer simulation has been developed. This mobility model is used to examine cell residence time distribution in cellular environments defined by different cell sizes and mobility parameters. It is shown that cell residence time can be described by the generalized gamma distribution.     

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。     

GSM数字移动通信系统的越区切换

切换技术是GSM数字移动通信系统保证移动中用户通信质量的一个重要手段。本文简要说明切换及其起因、启动标准和类型 ,并阐述基站决定切换启动的三个不同阶段的算法和要求 ,最后重点介绍网络系统中各种不同范围切换控制的信令关系及其实现过程。     

移动软交换中越区切换实现研究

软交换是下一代网络控制层中的核心实体,越区切换是移动软交换的重要功能之一。该文分析了越区切换的功能特点,研究了移动软交换中越区切换与呼叫控制和接入协议的关系。对越区切换进行了功能分解和分析,提出了一种可扩展性强、易于向3G演进的越区切换模块构建方式和越区切换状态机的实现方法。     

移动WiMAX系统中的切换优化方案分析

IEEE和WiMAX论坛相继针对移动WiMAX系统定义了标准的切换机制.为实现全移动的目标,应尽量减少移动WiMAX系统的切换时延,同时保证切换过程中数据的完整性.本文简单介绍了WiMAX系统基本原理和移动性管理机制,详细分析了在移动WiMAX系统中如何优化切换时延,同时提出了一种合理的保证数据完整性的切换方案.     

我国公用蜂窝移动通信发展的若干问题

本文在简要介绍国内外蜂窝移动通信发展动态的基础上，针对我国公用蜂窝移动通信发展的若干问题，例如市场分析与预测、技术发展走向、产业发展对策等阐述了作者的观点。     

浅谈WCDMA系统的切换技术

首先描述了切换的定义,切换的分类和切换的过程;接下来重点介绍了WCDMA软切换技术．包括：上下行链路的分析,功率控制,切换算法等;最后,通过具体的案例来加深对切换技术的理解。     

高速铁路场景移动通信系统切换研究综述

高铁的高速、全封闭特性给移动通信系统的越区切换性能带来了极大挑战,直接影响用户体验。阐述了移动通信系统中越区切换的概念,并指出高速铁路场景下越区切换面临的问题。回顾了国内外为解决这些问题所进行的相关研究及最新进展,包括网络架构优化和切换流程中测量、参数设置、执行策略、数据传输环节的优化,并指出群切换机制是未来值得关注的研究方向。     

Link Synchronous Mobile IPv4 Handover Algorithms

The performance of the base Mobile IP handover algorithm for moving the Mobile Node’s network layer point of attachment from one subnet to another has been recognized as a potential performance bottleneck for some time. In this paper, we discuss a collection of algorithms that use a link synchronous approach to Mobile IP handover. In the link synchronous approach, information on the progress of switching the link is used to drive handover at the IP level. We present a comprehensive analysis of handover packet drop, and develop analytical models of how the link synchronous algorithms help to mitigate it. We use data from a handover emulator to test the analytical models, and to compare the performance of the different algorithms under a variety of link conditions. Data from implementations on IS-2000 and 802.11b show how the link synchronous algorithms behave on real radio protocols. The results indicate that the link synchronous algorithms can reduce packet loss substantially, with best results possible if the link layer provides information on the move prior to the link switch. James Kempf is a Research Fellow at DoCoMo USA Laboratories. He holds a Ph.D. from the University of Arizona, Tucson, AZ. Previously, James worked at Sun Microsystems for 13 years, and contributed to numerous research projects involving wireless networking, mobile computing, and service discovery. James is a former member of the Internet Architecture Board, and co-chaired the SEND and Seamoby IETF Working Groups. James continues to be an active contributor to Internet standards in the areas of security and mobility for next generation, Internet protocol-based mobile systems. Ajoy Singh is a Principal Staff Engineer at Motorola GTSS Division where he has led the development of radio network controllers and the various components of core networks for 3GPP-based HSDPA and 3GPP2-based CDMA prototype systems. He holds a Master’s degree from DePaul University, Chicago, IL. Ajoy is the co-developer of several pending patents on cellular radio technology, and has contributed to the standardization of seamless mobility protocols through the Seamoby and Mobile IP IETF Working Groups and through IEEE 802.21. Jonathan Wood is an independent contractor and has been working with DoCoMo Labs since 2001. He is currently contributing to research on next generation mobility and networking infrastructures. Previously at Sun Microsystems, Jonathan focused on Solaris networking and 4G wireless network research. Atsushi Takeshita is a Director at the NTT DoCoMo Multimedia Laboratories in Yokoska Research Park, Japan. Prior to that, he was Director of the Autonomous Communication Laboratory in DoCoMo USA Laboratories, and one of the founding members of DoCoMo USA Laboratories. Atsushi joined NTT DoCoMo in 1988 and has since been engaged in the research and development of multimedia information retreival and delivery, the mobile Internet, and mobile terminal architectures. He is a member of the Association for Computing Machinery (ACM) and Information Processing Society of Japan. Nat Natarajan joined Motorola in 1993, and is a Fellow of the Technical Staff at Motorola. He received his Ph.D. from Ohio State University in Columbus, OH. Prior to working at Motorola, Nat served as a research staff member for over 12 years with IBM Thomas J. Watson Research Center, Yorktown Heights, NY, working primarily on packet switched data, voice and integrated networks as well as wireless data and satellite networks, and he has been a major contributor to the IEEE 802.11 standard approved in 1997. Nat is a Motorola Distinguished Innovator, holding 30 patents, and is a Senior Member of IEEE. Nat’s current technical interests are Beyond 3G/4G mobile networking systems based on IP technologies.