第三代移动通信系统

１第三代移动通信系统概述 第三代移动通信是覆盖全球的多媒体移动通信。它的特点是：（１）可实现全球漫游,使人们可在任意时间、任意地点进行交流;（２）能实现高速数据传输和宽带多媒体服务。用第三代手机除了可进行普通的寻呼和通话外,还可上网读报纸、查信息、下载文件和图片,并可传输图象,提供可视电话业务。 第三代移动通信系统的主要特征是可提供移动多媒体业务,其设计目标是能提供比第二代系统更大的系统容量及更好的通信质量,能在全球范围内更好地实现无缝漫游,为用户提供包括话音、数据及多媒体等在内的多种业务,同时也…     

第三代移动通信系统的QoS和资源管理

最近，移动互联网得到了迅猛发展，第三代移动通信系统为了提供移动多媒体业务，一个关键要素是必须要有QoS。本介绍了UMTS QoS结构和要求，并分别讨论了3G空中接口、无线接入网和核心网中的QoS。     

第三代移动通信系统

本文对现代移动通信系统的体制和发展前景,并就第三代移动通信系统中的关键性多址技术CDMA作了简要介绍,最后就第三代移动通信系统在我国的发展作了展望。     

第三代移动通信系统的网络问题

本文详细讨论了第三代移动通信系统的网络问题,介绍了三种网络方案,以及第二代网络向第三代网络的进化方式。     

第三代移动通信系统CDMA的关键技术

在３Ｇ系统中,ＣＤＭＡ系统成为了最具竞争力、最具发展前景的无线多址技术。虽然ＣＤＭＡ扩频技术可以采用直接序列扩频(ＤＳ)、跳频(ＦＨ)、跳时(ＴＨ)以及它们的组合等,但在移动通信中一般选用直接序列扩频,它构成了我们常说的ＤＳ－ＣＤＭＡ系统。３Ｇ系统结构如图１所示,它的核心网是在ＧＳＭ系统的核心网ＧＳＭ—ＭＡＰ和ＡＭＰＳ、ＩＳ—９５的核心网ＡＮＳＩ—４１的基础上发展而来的,其空中接口和相应的２Ｇ系统后向兼容。它的３种工作模式为:单载波频分双工、多载波频分双工和时分双工方式。     

第三代移动通信系统特征和标准化

详细介绍了３Ｇ系统的特征和无线接口协议，并提出了３Ｇ的系统结构。     

第三代移动通信系统的QoS和资源管理

随着通信网络的不断完善，用户对网络所提供的业务性能的要求不断提高，QoS（服务质量）已经成为通信系统的一个非常重要的指标，决定了用户的满意程度。本文概述了第三代移动通信系统（3G）的QoS和资源管理，其中着重描述了全球移动通信系统（UMTS）的QoS。     

第三代移动通信的关键技术

介绍了第三代移动通信系统的体系结构和关键技术。     

Traffic model for third generation cellular mobile telecommunication systems

Traffic analysis for third generation mobile telecommunication systems should take into account a variety of services (e.g., voice, data, video) and environments (private, public outdoor, public indoor) as well as the user mobility behavior. The analytical traffic model presented in this paper incorporates all the above mentioned features. The model utilizes a set of simplifying assumptions regarding the distribution of certain random time intervals (e.g., call duration and cell residence time) and the handover arrival process. The core of the model focuses on the estimation of the cell border crossing rate and the time it takes a busy mobile user to leave a cell area. This allows for the estimation of the handover rate and the call duration within a cell, which in turn, utilizing an iterative method, allows for the calculation of the offered traffic load per cell. The major advantages of the model are: (a) the simple closed form solutions, (b) its independence from the applied radio resource management scheme, and (c) its accuracy. The latter is validated via a simulation tool, which accommodates different cell-layout scenarios over a geographical area, representing a typical city center, modeled as a Manhattan grid.     

第四代移动通信系统及其最新网络架构

首先描述了4G的特点及相关技术,然后介绍4G的网络架构及最新提出的"WIISE"网络架构,最后对4G的发展进行了展望.     

浅谈第三代移动通信网络安全

介绍了对移动通信网络安全框架的理解,并以3GPPR4、3GPPR6和3GPPR8有代表性的3G网络为研究对象,从用户域、接入域、网络域、业务域和安全算法的发展讨论第三代移动通信网络安全技术的发展现状。并提出了国内第三代移动通信网络存在的安全问题。     

UMTS universal mobile telecommunications system: development ofstandards for the third generation

The standards for the universal mobile telecommunications system (UMTS) are being developed by the European Telecommunications Standardization Institute (ETSI), UMTS is a set of standards aimed at the global market. It will be a real third-generation global system for mobile communications, adding new features and introducing relevant technological innovations while evolving from both a global system for mobile communications (GSM) and integrated services digital networks (ISDNs), UMTS standardization is a market-driven process, and UMT standards are based on the carefully selected market requirements developed in close cooperation with the UMTS Forum and GSM Memorandum of Understanding Association (MoU), UMTS belongs to the IMT-2000 family and, while supporting existing services, will be capable of offering new and revolutionary services including multimedia and access to the Internet, offering a speed of 2 Mb/s for a single user at a radio-access network. This paper attempts to give an objective view of the UMTS standardization in Europe     

Harmonization of global third generation mobile systems

The International Telecommunication Union launched the third-generation project in 1986 with the aim to provide global personal communication using an inexpensive mobile terminal that can truly facilitate communication "anywhere, anytime". In previous years, standardization activities toward IMT-2000 have accelerated toward concrete specifications. By June 1998, a total of 15 proposals from around the world had been submitted to the ITU as radio transmission technology candidates. Since then, the 3G standardization landscape has seen many changes-a steady progression of the convergence process. This article provides a comprehensive overview of the worldwide harmonization efforts on the standardization of third-generation terrestrial mobile communication systems. The status, as of October 1999 when this article was written, of the technical specifications within 3G partnership projects are also summarized.     

My generation [third generation wireless mobile communication]

As the introduction of third generation (3G) mobile communications systems is expected to be evolutionary rather than revolutionary it is vital to establish a solid business case for 3G. The old business model of `coverage, coverage, coverage' will evolve to one of `capacity, capability and content' and a thorough evaluation will have to be made of the volume of expected usage, the value that customers will expect for their money and the variety of services that can be offered. The author discusses the business case for 3G and concludes that it will have to embrace `my generation' thinking, i.e. the need for equipment and services to be personalised     

第三代移动通信系统中应用的LDMOS器件

介绍了在第三代移动通信系统的基站中应用的 LDMOS器件的现状及关键技术     

Location management methods for third generation mobile systems

This article provides an overview of the means and techniques used for subscriber location management in present cellular mobile networks. The overhead due to location management techniques used in the present cellular systems such as GSM, in particular in high traffic spots, has already been a source of concern and is expected to augment dramatically in future wireless systems. Several proposals have been made in the past addressing the problem associated with the cost of location management. The author provides an overview of these contributions; in particular, he classifies the techniques, mainly into non-memory-based and memory-based approaches. Subsequently, a simple evaluation of the current location updating procedure used in GSM is presented in the context of a PCS framework to illustrate the load placed on the radio channels and on the MSC/VLR processing     

Access network evolution beyond third generation mobile communications

Second-generation mobile radio systems have been deployed successfully worldwide. These systems have evolved to higher data rates and packet transmission. Third-generation mobile radio systems are currently being standardized worldwide to be initially deployed in 2001 and 2002 in different regions of the world. New advanced multimedia services are under development, and first services are already being offered in second-generation systems, which will provide new business opportunities. Already today discussion is starting on the development of systems beyond third-generation mobile radio systems due to the long timeframe for system specification and international standardization. However, today there is no clear vision available on such systems. This discussion takes into account the new deregulated and liberalized communication environment. This article presents a concept for a system beyond third-generation mobile radio systems, which comprises a combination of several optimized access systems in a common IP-based medium access and core network platform. These different access systems will interwork through horizontal and vertical handover, service negotiation, and global roaming. The different access systems are allocated to different mutually complementing cell layers in the sense of hierarchical cells with respect to cell size, coverage, and mobility to provide globally optimized seamless services to users. This vision requires extensive international research and standardization activities to solve many technical challenges. Key issues are the global interworking of different access systems on a common platform, advanced antenna concepts, and the implementation of multimode and multiband terminals and base stations through software-defined radio concepts.