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。     

WCDMA、GSM、PHS局间切换流程比较研究

文章分别分析和比较了在国内移动通信领域占了主流地位的GSM系统和PHS系统、WCDMAR4网络的局间切换流程，概括了几种系统局间切换流程的本质不同及其根本原因。文章可以作为切换研究、MAP研究、R4与GSM兼容性测试的依据，并供一致性测试作为参考。     

几种无线通信系统的局间切换流程比较研究

分别分析和比较了在国内无线通信领域占了主流地位的GSM系统和PHS系统、即将投入建设的WCDMA R4网络的局间切换流程,概括了几种系统局间切换流程的本质不同及其根本原因。本文可以作为切换研究、MAP研究、R4与GSM兼容性测试的依据,并供一致性测试作为参考。     

WCDMA、GSM、PHS局间切换流程比较研究

文章分别分析和比较了在国内移动通信领域占了主流地位的GSM系统和PHS系统、WCDMA R4网络的局间切换流程,概括了几种系统局间切换流程的本质不同及其根本原因.文章可以作为切换研究、MAP研究、R4与GSM兼容性测试的依据,并供一致性测试作为参考.     

TD系统中小区间切换控制算法的研究

本文介绍了TD—SCDMA系统中切换的相关原理。重点介绍了TD—SCDMA系统中小区间的接力切换原理及其算法、接力切换对软切换和硬切换的技术优势等。最后对目前的切换技术的特点进行了总结,并提出了自己的看法。     

UMTS中切换的系统开销

本文首先建立了切换模型,并给出最常用的UMTS切换算法。在切换模型和切换算法的基础上,提出了UMTS硬切换和软切换的瞬时系统开销和平均系统开销的数学分析方法,推导出了两种切换的瞬时和平均系统开销的数学表达式。最后,通过仿真切换的系统开销的数学表达式,分析和对比了随着不同的切换门限变化和随着移动台在小区中不同空间位置变化,硬切换和软切换的瞬时系统开销的变化规律,并对比了UMTS硬切换和软切换的在整个切换过程中的平均系统开销的相对大小。     

CDMA 2000 1X RC1 ＆ RC2的切换技术

CDMA 2000 1X RC1＆RC2有其特有的切换技术,移动台在空闲状态、系统接入状态和通话控制状态下的切换方式及其实现各有不同,软切换只是其中之一.全面介绍了CDMA 2000 1X RC1＆RC2中各种切换方式及其具体实现.     

WCDMA系统中切换的研究

描述了WCDMA系统切换机制,着眼于切换的各种参数对切换的影响,切换对系统性能的影响．着重分析了同频软切换和异频硬切换这两种切换形式在同频软切换中详细分析了各种不同情况触发的软切换．并结合运营商的实际情况提出了一些建议。     

异构无线网络垂直切换技术综述

垂直切换是多网融合的基础,是实现异构网络互通、支持不同接入方式无缝衔接的核心技术,目前正在受到业界的重点关注,并成为学术界研究的热点问题。随着无线移动通信技术向接入多元化、网络一体化和应用综合化的方向发展,各种蜂窝移动接入、宽带无线接入和固定接入将共同接入基于IP的统一核心网络,通过网络间的垂直切换,支持用户的移动性和移动过程中业务的连续性。首先给出了垂直切换的定义和基本概念,介绍了垂直切换的分类和基本流程,随后详细论述垂直切换的切换判决和切换执行2个环节。针对切换判决,总结了现有判决算法,重点评述各代表算法工作原理并剖析论其特点和存在的不足。针对切换执行,详述了现有垂直切换执行机制的工作原理和适用场景,并分析其优缺点。最后,对未来垂直切换技术的研究方向进行了展望。     

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。     

切换成功率的改善

从现网统计发现同步切换与异步切换的切出数量比大约是1：4,异步切换的切出成功率比同步切换的切出成功率高1．6％,为了提高切出成功率,通过对同步切换的切出成功率低的原因进行细致分析,得出将同步切换调整为异步切换的合理性,并在现网推广实施后,有效改善了切出成功率。     

基于OPNET的UMTS切换技术的建模与仿真

切换技术是通用移动通信系统(Universal Mobile Telecommunications System,UMTS)的主要关键技术之一,用于保证用户在移动通信网络中的移动性。对目前主要使用的2种切换技术———软切换和硬切换进行了简要介绍,而软切换是码分多址(Code Division Multiple Access,CDMA)系统所特有的。利用OPNET仿真软件搭建了UMTS网络切换模型,对软切换及硬切换技术进行仿真,并对结果进行了比较分析,得出结论,切换技术的优劣会直接影响到系统提供的服务质量。     

Handover approaches for seamless mobility management in next generation wireless networks

Next generation wireless networks (NGWN) will be an integration of heterogeneous wireless access networks that will interwork over an IP‐based infrastructure. This all‐IP vision has led to the development of handover mechanisms to support seamless mobility for active network services among the different interworking wireless networks in order to ensure network access ubiquity in NGWN. These handover mechanisms need to ensure that mobile devices continue to receive ongoing communication without any noticeable disruption during handover events among the heterogeneous networks. This paper gives a qualitative and quantitative review of current handover approaches of IP mobility management protocols for NGWN with an objective to introduce a new way of further optimizing the handover performance. In particular, the paper focuses on handover approaches of mobile IPv6 (MIPv6) based mobility management protocols. Thus, the need, benefits, and limitations of these handover approaches are explored. Thereafter, dynamic handover coordination is introduced as a new viable solution that exploits the benefits and mitigates the limitations of these handover approaches hence improving handover performance in terms of handover delay, packet loss, and signaling overhead. Copyright © 2011 John Wiley & Sons, Ltd.     

TD-SCDMA通信系统中接力切换问题研究

第三代移动通信系统TD-SCDMA中采用了一种新型的越区切换技术--接力切换.介绍了接力切换的基本概念、切换过程和切换算法,并综合硬、软切换技术,对其性能进行了比较,分析表明,接力切换在整体上提高了系统的性能.     

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。     

TD-SCDMA系统接力切换技术及仿真

越区切换是蜂窝移动通信系统中的关键技术之一,第三代移动通信系统TD-SCDMA中采用了一种新型的越区切换技术—接力切换。文章在完整阐述其基本概念、切换过程和切换算法的基础上,对比硬切换方式,建立切换仿真模型并进行了仿真,得到上行传输功率和FTP业务上传响应时间的性能参数曲线。仿真结果证明,接力切换在降低上行干扰、缩短切换时延、降低掉话率方面性能更加优良。     

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。     

A novel media independent handover‐based approach for vertical handover over heterogeneous wireless networks

The key purpose for seamless mobility and service continuity between heterogeneous wireless networks is the handover. Vertical handover management is one of key challenges in such environment. To deal with some of these challenges, an IEEE 802.21 media independent handover (MIH) framework has been standardized. The main purpose of this standard is to offer a general interface for the handover by abstracting the link layer intelligence to higher layers. However, there still exist a number of limitations in MIH architecture. In this paper, a new architecture of improved MIH is presented to perform vertical handover between wireless heterogeneous networks. We focused on interworking architecture between wireless local area network and long term evolution advanced network with the use of MIH signaling to define an efficient vertical handover. A performance analysis model for the proposed MIH‐based vertical handover is derived. Analysis results show that the proposed method can be easily deployed in present multimedia service networks. Copyright © 2013 John Wiley & Sons, Ltd.     

Efficient handover measurement technique for small‐cell networks using a virtual cell synchronization signal

A small‐cell network (SCN) constructed by splitting a macro‐cell into numerous small cells using an active antenna array system is studied. A synchronization signal appropriate for the SCN, virtually generated by an eNodeB with 3D beamforming, is proposed for efficient handover in SCNs. The virtual cell synchronization signal (VCSS) carries a macro‐cell ID (MCID) and virtual‐cell ID (VCID) in a hierarchical manner, allowing us to distinguish between an intra‐cell handover (virtual cell handover within a cell without changing the serving eNodeB) and inter‐cell handover (virtual cell handovers across cells while changing the serving eNodeB) in SCNs. Using the signal metrics obtained by the VCSS, an efficient handover measurement technique is proposed which can significantly reduce the processing time and overhead by distinguishing between the intra‐cell/inter‐cell handovers. The performance of the proposed technique is evaluated by simulating two different deployment scenarios of LTE‐based SCN with 3D beamforming. Copyright © 2017 John Wiley & Sons, Ltd.