WCDMA软切换的规划

概述了WCDMA网络中的软切换和硬切换,分析和探讨软切换的算法和规划,接着介绍同时列举了与切换相关的网络性能指标。     

WCDMA的切换参数对系统设计的影响研究

介绍了WCDMA系统的切换控制机制，比较了硬切换和软切换的不同特点，分析了切换参数对系统性能的影响。     

CDMA系统中切换性能的界限和变动范围

该文提出了CDMA系统中切换性能的3个界限的数学表达式,以及建立在界限基础上的硬切换性能差异、软切换性能差异和软切换增益的变动范围的表达式,并通过这些公式对切换的性能空间做了划分和限定。作为上述分析的数学基础,该文推导了硬切换和软切换中断概率的表达式。最后,通过对WCDMA(FDD)系统的仿真,证明了切换的界限、变动范围和中断概率的公式的正确性,并且指出,使用它们刻划实际切换算法的性能将比Viterbi的估计更为准确和恰当。     

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。     

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。     

WCDMA的软切换和TD-SCDMA的接力切换算法的分析与比较

本文首先介绍了第三代移动通信中的WCDMA、TD-SCDMA和CDMA2000,接着分别概述了WCDMA和TD-SCDMA切换的概念、过程和算法分析,最后比较了WCDMA软切换算法与TD-SCDMA接力切换算法各自的特点。     

第三代移动通信系统WCDMA中的软切换技术

WCDMA是第三代移动通信系统中的一种主流无线接入技术。论文介绍了WCDMA网络中软切换的分类，分析了软切换的执行策略和其中的重要参数，用系统级仿真的研究方法探讨了软切换门限和软切换比例，软切换门限和掉话率、阻塞率之间的关系，最后得出合适的软切换增加门限应该在3db～6db，软切换删除门限在5db～8db，为实际应用中进行参数设置提供了参考。     

浅议3G中的各种切换技术

在第三代移动通信系统中．软切换已被作为种关键的技术广泛应用。本文详细论述了WCDMA、CDMA2000系统中的软切换和TD-SCDMA系纺中的切换策略及其执行过程，尤其是TD-SCDMA中的接力切换．并对他们的切换性能做了简单的比较。     

WCDMA中几种常见软切换算法评估

软切换是WCDMA系统所具有的技术特点，它不仅提高了通信的可靠性，而且改善了系统的性能。文中简要介绍了WCDMA中软切换的概念和软切换的基本过程，较详细地说明了几种常见的软切换算法，最后分析了这些算法的评估指标及其仿真结果。     

WCDMA无线接入网络的软切换研究

本文对WCDMA的软切换原理进行了详细的阐述,分析了影响软切换的因素和软切换对网络性能的影响。     

The Complementary Use of 3G WCDMA and GSM/GPRS Cellular Radio Networks

The traffic performance of integrated 3G wide-band code division multiple access (WCDMA) and GSM/GPRS network is evaluated. This type of network links two cellular radio systems which have different set of frequency bands and the same coverage size. The base station of 3G WCDMA is installed on an existing GSM/GPRS site. Dual-mode mobile terminals use handoff to establish calls on the better system. The soft handoff or inter-frequency hard handoff occurs when mobile terminals of 3G WCDMA or GSM/GPRS move between two adjacent cells, respectively. The inter-system hard handoffs are used between 3G WCDMA and GSM/GPRS systems. The data rate conversions between different systems, soft handoff region size, multiple data rate multimedia services, and the effect of the mobile terminal mobility on the user mean dwell time in each system are considered in the study. The simulation results demonstrate that a great traffic performance improvement on the complementary use of 3G WCDMA and GSM/GPRS cellular radio networks compared with the use of GSM/GPRS cellular radio networks. When high-data rate transmission is chosen for low-mobility subscribers, both the handoff failure probability, and carried traffic rates increase with the new call generation rate. However, both rates decrease conversely with the increasing new call generation rate as soon as the new call generation rate exceeds a critical value. This causes the integrated networks saturation. The higher mean speed for the mobile terminals produces lower new call blocking probabilities and total carried traffic. The new call blocking probabilities and total carried traffic increase with the size of the soft handoff region.     

移动因特网不同流量下切换损失率研究

根据移动因特网中基本的硬切换和改进的半软切换算法时间流程仿真研究了 2种切换在泊松和自相似流量下的切换损失率。仿真数据表明 ,在网络负载均值相同的情况下 ,对于硬切换和半软切换 ,自相似流量的切换损失率要明显低于传统泊松流量 ,并通过分析泊松和自相似流量的概率密度函数尝试给出产生这一区别的原因。     

移动因特网半软切换的仿真研究

MobileIP协议中原有的硬切换算法产生的分组丢失和切换时延大大降低了用户的通信质量，半软切换算法是硬切换的改进算法，本文通过仿真比较了Mobile IP协议中硬切换和半软切换对TCP和UDP流量的影响，并进一步研究了影响半软换性能的因素。     

无线异构网络的垂直切换

传统意义上的水平切换算法已经在同构网络中得到很好的研究和应用,而随着多种无线异构网络的出现,下一代网络必须支持垂直切换技术以保证用户从一种类型的网络切换到另一种类型的网络时仍然保持连接。由于切换算法所需考虑因素的多样性和算法本身的复杂性,有必要对现有文献中的网络切换类型、切换因素、切换算法进行了归纳总结,并对垂直切换算法进行比较,指出未来切换算法的研究方向。     

MCIP: A 3G/IP Interworking System Supporting Inter-Cluster Soft Handoff

In this paper, a novel 3-tier Mobile Cellular IP (MCIP) access network is proposed for interworking between a third generation (3G) wireless cellular system and a wireline Internet Protocol (IP) based network. An inter-cluster hard handoff scheme and an inter-cluster soft handoff scheme are proposed, based on the 3-tier MCIP system model, the core network protocol stacks, and the underlying MCIP routing algorithm. The core network protocol stack is presented to integrate the 3G radio interface and the IP-based core network, and to provide the access network with capability to support soft handoff macroscopic space diversity. The MCIP hard and soft handoff schemes are compared with the hard handoff schemes used in the Cellular IP and HAWAII access networks. The MCIP access network is more efficient in terms of signaling cost, but has the same scalability as Cellular IP and HAWAII. Both MCIP hard and soft handoff schemes enable IP packets to be delivered within the MCIP access network in-order without loss and duplication, a highly desired attribute for real-time multimedia applications. The advantages of supporting soft handoffs and quality-of-service (QoS) provisioning for real-time services are achieved at slightly increased system complexity.This work was supported by a research grant from the Natural Science and Engineering Research Council (NSERC) of Canada. The authors wish to thank the anonymous reviewers for their helpful comments and suggestions which improve the presentation of this paper. Xin Liu received his B.E. and M.E. degrees in radio engineering from Harbin Institute of Technology (China), in 1990 and 1993, respectively, and his M.A.Sc degree in electrical engineering from the University of Waterloo in 2002. He joined Research In Motion in 2002 as a firmware developer. His current work involves GSM/GPRS and WCDMA firmware development. Weihua Zhuang received the B.Sc. and M.Sc. degrees from Dalian Maritime University (China) and the Ph.D. degree from the University of New Brunswick (Canada), all in electrical engineering. Since October 1993, she has been with the Department of Electrical and Computer Engineering, University of Waterloo, Canada, where she is a full professor. She is a co-author of the textbook Wireless Communications and Networking (Prentice Hall, 2003). Her current research interests include multimedia wireless communications, wireless networks, and radio positioning. Dr. Zhuang received the Premier's Research Excellence Award (PREA) in 2001 from the Ontario Government for demonstrated excellence of scientific and academic contributions. She is an Editor of IEEE Transactions on Wireless Communications, an Associate Editor of IEEE Transactions on Vehicular Technology, and an Editor of EURASIP Journal on Wireless Communications and Networking.     

基于RSS准则的CDMA软切换越区研究

硬切换技术中移动台在接收新基站信号之前中断与原基站的通信,通信中断的概率非常大。而软切换技术需要先建立与新基站之间的通信,等接收到原基站信号低于门限值时再切断与原基站的通信,故具有很高的可靠性。采用接收到的信号强度准则对软切换建立仿真模型,对两个小区之间的软切换进行了仿真,仿真结果表明,软切换的可靠性高于硬切换,采用软切换技术降低了系统的掉话率,提高了通信质量。然而,软切换也将使系统的复杂度和信道开销有所增加。     

CDMA网多载频实施方案探讨

主要探讨了在CDMA网络设计时，如何考虑空闲状态时终端的守候方式、终端业务请求时网络资源的分配方式以及跨载频硬切换的解决方案这3个方面的问题。     

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。     

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.