GSM系统越区切换简介(上)

介绍了越区切换的基本概念和基本过程,包括ＧＳＭ 规范中建议的越区切换算法和主要流程,以及定向重试流程和ＧＳＭ ／ＤＣＳ 双频切换两个较新的概念     

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...     

GSM系统越区切换简介(下)

５　ＧＳＭ系统越区切换流程ＧＳＭ系统越区切换流程可按切换区域不同分类。首先可把切换分为：ＭＳＣ内部切换和ＭＳＣ之间切换。为了说明方便,文中定义了如下缩写：ＢＳＳＡ、ＢＳＣＡ和ＢＴＳＡ分别是ＭＳ切换之前所在的ＢＳＳ、ＢＳＣ和ＢＴＳ;ＢＳＳＢ、ＢＳＣＢ和ＢＴＳＢ分别是ＭＳ切换之后所在的ＢＳＳ、ＢＳＣ和ＢＴＳ;ＭＳＣＡ是控制最初呼叫建立的ＭＳＣ;ＭＳＣＢ是ＭＳ在基本切换时所切换的目标ＭＳＣ;ＭＳＣＢ′是ＭＳ在后续切换时所切换的目标ＭＳＣ。图２　ＢＴＳ之间切换流程５．１　ＭＳＣ内部切换…     

移动通信系统中的越区切换技术研究

针对切换策略和算法是决定3G网络性能好坏的关键因素之一,文章简单介绍了越区切换的原因,对越区切换的策略进行相关的论述,最后主要介绍了几种典型的越区切换算法,着重对资源预留和呼叫请求排队联合切换算法做了详细的分析.     

蜂窝网越区切换方案的研究

论文对无信道预约优先的模型、具有信道预约优先的模型、信道预约优先和排队优先相结合的切换模型，以及支持话音和数据多业务的切换模型等几种典型的越区切换模型进行了研究概括。分别对其系统模型进行描述，用马尔可夫进行数学建模。最后，研究了支持多业务的具有复合优先权的越区切换策略，比较了现有文献的特点，提出了今后的工作方向。     

GSM—R网络越区切换性能研究

GSM—R（GSM for Railway）是以GSM（全球移动通信系统）为平台,集列车公务通信和区间通信为一体的铁路专用移动通信系统,已经成为我国铁路通信技术的发展方向。越区切换是GSM—R系统的关键技术之一,由于列车速度的提升导致多普勒效应更严重、切换位置更靠后、越区切换更频繁,最终GSM—R的安全性和可靠性会严重降低,因此对越区切换的研究具有非常重要的意义。本文分析了GSM—R网络越区切换掉话的原因并提出了优化方案。     

多区集群移动通信系统及其越区切换的实现

多区制是集群移动通信系统的发展方向，本文探讨了多区集群系统的实现方法及其特点。在参照蜂房网的越区切换方法的基础上，提出了多区集群系统的越式切换的简单的实现方法。     

浅谈蜂窝区移动通信系统中的频道切换

CDMA技术是未来全数字化移动通信系统最有希望的发展方向。本文围绕蜂窝区移动通信系统中的频道切换进行了较为详细的论述 ,包括越区切换、越局切换和漫游 ,并介绍了CDMA软切换技术的优越性及其切换原理。     

WCDMA与GSM系统间切换浅析

本文介绍了WCDMA系统和GSM系统间切换和小区重选的操作过程,分析了压缩模式对网络质量的影响,并对提高切换成功率提出了几点建议.另外,本文对切换相关的GSM网络升级和测量控制参数的设置也进行了讨论.     

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。     

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.     

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.     

TD-SCDMA/GSM双模终端切换问题的研究

TD-SCDMA系统是第三代蜂窝移动通信网络系统,在由2G向3G的过渡阶段,为了保证其过渡的连续性和平滑性,TD-SCDMA与GSM系统间的切换问题显得尤为重要.本丈详细讨论了TD-SCDMA/GSM双模终端在两种制式间切换的问题并提出解决方法,设计双模终端协议栈结构,并研究它们相互切换的具体过程,过程符合协议要求.     

移动通信系统中切换技术分析

文中讨论了移动通信系统中切换技术提出的背景及其基本概念，然后分别介绍了三代移动通信系统中所采用的切换技术。最后详细分析了TD-SCDMA移动通信系统中所采用的接力切换技术和WiMAX系统的切换技术的原理及其实现，对系统地学习和研究移动通信系统中切换技术具有重大意义。     

一种新的分层移动IPv6快速切换方案研究

分层移动IPv6快速切换在一定程度上减少了切换延时，但切换过程中由网络层移动检测和使用重复地址检测（DAD）配置一个新转交地址引起的延时对实时业务仍然有很大的影响。为了减轻这些影响，文中提出了一种更加有效的快速邻居发现和DAD机制，减小了切换延时，提高了网络的性能。     

GSM网络切换参数优化对掉话的改善

本文重点介绍和分析了通过对切换参数的优化调整,从全网角度改善掉话的优化方法.