A vision of UMTS/IMT-2000 evolution

A vision is presented for a fully IP-based mobile network which goes beyond UMTS/IMT-2000. A top-to-bottom design approach is introduced that is capable of offering new and innovative services and applications to both fixed and mobile users efficiently, cost effectively and in a user-friendly manner. Some issues and examples in the design steps following this new approach are discussed. It is clearly shown that the convergence of mobile and fixed networks will be achieved naturally through the use of an `all IP' based solution for both access and core networks     

UMTS/IMT-2000 based on wideband CDMA

The UMTS terrestrial radio access is based on wideband 4.096 Mchip/s DS-CDMA technology. UTRA will be connected to an evolved GSM core network for both circuit and packet services. A merger between ETSI/Europe and ARIB/Japan based on W-CDMA, a GSM core network, and a common frequency allocation according to the ITU Recommendation of 2 GHz makes a global IMT-2000 standard feasible. UTRA based on W-CDMA fully supports the UMTS/IMT-2000 requirements (e.g., support of 384 kb/s for wide-area coverage and 2 Mb/s for local coverage). Furthermore, the air interface has flexible support of mixed services, variable-rate services, and an efficient packet mode. Key W-CDMA features also include improved basic capacity/coverage performance compared to second-generation systems, full support of adaptive antenna arrays, support of hierarchical cell structures with interfrequency handover, and support of asynchronous inter-base-station operation. There have been no constraints due to the strong requirements for backward compatibility with second-generation systems. This has facilitated a high degree of flexibility and a future-proof air interface. Extensive evaluations by means of simulations and field trials have been carried out by a number of companies, and full system tests are ongoing. Consequently, W-CDMA technology can now be regarded as a mature technology, ready to provide the basis for UMTS/IMT-2000     

Wide-band CDMA for the UMTS/IMT-2000 satellite component

This paper describes the main aspects relevant to the development of a third-generation radio transmission technology (RTT) concept identified as satellite wide-band CDMA (SW-CDMA), which has been accepted by the International Telecommunications Union (ITU) as one of the possible RTTs for the satellite component of International Mobile Telecommunications-2000 (IMT-2000). The main outcomes of the extensive system engineering effort that has led to the above ITU RTT are described. In particular, we address propagation channel characteristics, satellite diversity, power control, pilot channel, code acquisition, digital modulation and spreading format, interference mitigation, and resource allocation. Due to its similarity with respect to the terrestrial W-CDMA proposal from which it is derived, the SW-CDMA open air interface solution is described briefly, with emphasis only on the major adaptation required to best cope with the satellite environment. Quantitative results concerning the physical-layer performance over realistic channel conditions, for both forward and reverse link, are reported. A system capacity study case for a low-Earth-orbit constellation is also provided     

IMT-2000无线通信标准

国际无线通信联盟（ＩＴＵ）于去年 １１月在赫尔辛基会议上最终确立了ＩＭＴ－２０００标准。在不偏袒现有任何一个协议的情况下，这一协议为所有主要的无线通信协议提供了统一的３Ｇ（第三代）无线通信平台。有了ＩＭＴ－２０００标准，互相竞争的无线通信技术将在３Ｇ世界里共存，并可在一个框架下做到互相连接。 两年多来，无线系统供应商一直在为适用于第三代（３Ｇ）无线通信网络的最好平台争吵。一个无线平台的主要结构层包括一个基础的核心网络和相应编码、处理、传输的无线通信协议。为满足目前手机、ＰＤＡ（个人数字助理）和其它…     

Satellite UMTS/IMT2000 W-CDMA air interfaces

The third-generation IMT-2000 initiative of the International Telecommunication Union is aiming at the provision of a limited family of global standards providing worldwide multimedia wireless services in a host of environments encompassing indoor picocells to satellite megacells. The ITU IMT-2000 initiative has been supported by several regional standardization bodies such as the European Telecommunication Standard Institute with its Universal Mobile Telecommunication System. In this article a few air interface proposals for the satellite component of UMTS/IMT-2000 based on adaptation of the emerging terrestrial wideband CDMA standards are reviewed. In particular, S-UMTS requirements are examined together with W-CDMA applicability to the satellite environment. It is shown that with minor adaptations, the terrestrial W-CDMA air interface provides an efficient solution for the satellite UMTS component. This commonality will certainly help in the realization of low-cost low-size dual-mode user terminals encompassing both terrestrial and satellite components     

IMT—2000系统网络概述

简要介绍了国际电联 (ITU)建议的 IMT- 2 0 0 0网络技术方面的特点 ,以及 ITU的相关建议制订情况 ,阐述了IMT- 2 0 0 0家族的概念、网络的兼容和过渡及网络实现的原则和方案。     

3G/IMT-2000的移动性管理分析

第三代移动通信系统(3G)的重要特点是支持覆盖全球的综合多媒体业务,包括高速到低速移动、室外到室内的各种系统运营环境.由于它的全球性服务与全球性网络设计,3G的移动性管理成为近年发展迅速热点研究领域之一.本文对3G分层系统的移动性管理进行分析,提出优化步骤并进行讨论,得出3G分层系统较3G单层系统性能要好.     

Dielectric resonator antenna for dual-band PCS/IMT-2000

A novel broadband and small dielectric resonator antenna has been investigated experimentally and numerically. A bandwidth of 25% has been achieved, and an omni-directional radiation pattern obtained. These features make such antennas highly suitable for application to mobile handsets     

第三代移动通信的频率和牌照问题

介绍了ITU对IMT－2000频率的分配建议和欧、美、亚洲一些国家在频率分配上的实际情况,详细介绍了这些国家3G牌照发放政策和情况。     

移动通信后3G或4G技术前景探索

对移动通信前20余年的发展略予回顾，指出其现状差强人意之处。阐述了当前世界各国相关业界对于新一代移动通信技术发展的一些要求、设想和探讨。     

An introduction to access security in UMTS

The first generation of cellular mobile communications systems contained few if any security measures to protect the system operator and users. The second generation generally did a lot better, and contained entity authentication and confidentiality protection. Although this was a major improvement, security protection in the second generation left a lot to be desired. With the advent of 3G mobile systems a serious effort has been made to create a consistent security architecture based on the threats and risks a 3G system faces.     

Broadband sleeve monopole type antenna for dual-band PCS/IMT-2000

A modified sleeve monopole type antenna that features a novel broadband technique is demonstrated experimentally and numerically. A bandwidth of 24.2%1 (|S₁₁|<-20 dB) can be achieved, and an omnidirectional radiation pattern is obtained. The electrical characteristics of the proposed antenna make it attractive for use in mobile handset and repeater applications     

The 3GPP proposal for IMT-2000

Market expectations for third-generation mobile radio systems (IMT-2000) show an increasing demand for a wide range of services from voice to low, high, and advanced data rate services to support mobile multimedia. This leads to technical requirements for IMT-2000 which are currently being standardized worldwide. Circuit- and packet-oriented services will be supported. These systems will operate in all radio environments to provide service to anyone, anytime, anywhere. The ITU has identified spectrum for the allocation of IMT-2000. However, these frequency bands are currently not available worldwide. In different regions research activities on IMT-2000 have been initiated to support the international consensus building process and standardization activities. Based on these activities system proposals have been submitted to ITU TG 8/1. In particular, the newly formed Third Generation Partnership Projects 3GPP and 3GPP2 have the objective of harmonizing similar proposals and defining detailed standards. Proposals from Europe, Japan, Korea, and the United States are very similar. The evolution and migration of second-generation systems to the third generation takes into account the deployed investment to save today's investment where useful and necessary. This article focuses on market and technical requirements and, in particular, the technical approach of 3GPP based on the big footprint of the GSM system     

Broadband loop antenna for DCS-1800/IMT-2000 mobile phone handsets

A rectangular loop antenna is proposed for DCS-1800 and IMT-2000 mobile phone handsets. By introducing a small gap in the wire loop, an impedance bandwidth of 24% can be achieved. The antenna mounted on a metal box is simulated using the FDTD method. It is found that the introduction of a small gap also results in a radiation pattern with desirable polarization independence and a reduced gain in the direction of the user's head. The simulated and measured results are presented.     

Current development of IMT-2000 in China

This article describes the current development of mobile communications in China, including market demand, operators, and technologies. The reasons China put great emphasis on IMT-2000 research and development are discussed. An IMT-2000-related organization structure is given, and their different responsibility and latest progress are also described. Finally, the author gives some viewpoints on IMT-2000     

超3G研究的最新进展

超3G在ITU—R范围内的各项研究工作还刚刚开始．基本上还处于制定工作计划的阶段。但目前关于对超3G频率需求计算方法的研究．已经有一些国家提出了自己的建议，主要是日本和德国。超3G研究工作。特别是频谱计算、业务预制、新的无线接入和核心网技术方面研究工作的开展，对我国的研究机构、相关公司和高校都是一个继续赶超世界先进通信技术．获取成果的绝好机会。     

IMT-2000的融合、演进新进展

论述了有关IMT-2000的融合、演进新进展。     

An HTS 21-pole microstrip filter for IMT-2000 base stations with steep attenuation

We developed a 21-pole high-temperature superconductor thin-film microstrip filter with steep attenuation. This filter is applicable in the International Mobile Telecommunications-2000 (IMT-2000) base station receiver system, where high selectivity is needed to avoid interference from signals in the personal handyphone system (PHS) band just below the IMT-2000 band. The out-of-band rejection of this filter 1 MHz below the passband edge is more than 40 dB. Owing to the improvements of the design and the fabrication processes, we also eliminated the need for a tuning process in the fabrication processes in order to reduce the production costs and the turnaround time.     

基于CDMA的IMT-2000空中接口方案简介

围绕第三代移动通信系统IMT - 2 0 0 0标准 ,各国间正展开激烈的竞争 ,提交ITU的地面候选方案多达 10种。由于CDMA具有容量大、频谱利用率高、频率规划方便等优点 ,IMT - 2 0 0 0候选标准已基本上统一到基于CDMA方案上。本文先简要介绍了第三代CDMA空中接口的特征 ,然后分别介绍呼声最高的两种方案的空中接口标准 :W -CDMA和cdma2 0 0 0。