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     

Current IMT-2000 R&D status and views in Korea

In this article Korean development of IMT-2000 is considered. It includes the second-generation digital mobile communications, R&D and standardization activities related to IMT-2000, and the authors' perspectives on IMT-2000 in Korea. In Korea, there are many activities for development of IMT-2000 radio transmission technologies, and the results of these activities will be the submission of technologies to the ITU. However, the Korean telecommunications standardization body (TTA) will make every effort to make a common global standard for IMT-2000. Therefore, the TTA will make a domestic standard for IMT-2000 after the ITU finalizes the related Recommendations. It seems to the authors that difficulties in harmonization in the TTA are very similar to difficulties in harmonization worldwide. The only way of reaching the harmonization of IMT-2000 in Korea is that the key players should have the view from the end users' seat     

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     

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     

Experiments on IMT-2000 Using Unmanned Solar Powered Aircraft at an Altitude of 20 km

Several countries are keenly interested in the research and development of novel wireless communication systems using high altitude platform stations (HAPS) because of their great potential benefits. In June and July 2002, we carried out the world's first experiment on International Mobile Telecommunication 2000 (IMT-2000) by radio relay via transponders onboard an unmanned solar powered aircraft at an altitude of 20 km. This experiment demonstrated for the first time the feasibility of applying the IMT-2000 system using a HAPS and a compact cellular phone designed for terrestrial cellular systems. Two experiments were carried out over Kauai Island in Hawaii, USA. In the first experiment, we were unable to establish an IMT-2000 link connection via the aircraft at 20 km because the onboard transponder for the reverse link received unexpected signals from a terrestrial cellular system in commercial use 200 km away on Oahu Island. However, we managed to establish the link by connecting a high gain external antenna to the cellular phone. After the first flight experiment, we developed an onboard receiving antenna with a low sidelobe level to suppress interference signals. In the second experiment, we successfully achieved IMT-2000 video communication with a cellular phone. This paper presents the experimental results and analysis of these IMT-2000 communication experiments.     

TD-SCDMA──中国的IMT-2000RTT方案

简要介绍了第三代移动通信系统的研究开发情况,并对我国第三代移动通信系统无线传输技术IMT－2000RTT方案（时分-同步码分多址）作了深入探讨。     

云南省第三代移动通信系统应用的探讨

本介绍了第三代移动通信系统ＩＭＴ－２０００的发展、运用及前景。结合云南省移动通信系统的现状，对云南省ＩＭＴ－２０００的应用及采用模式，可能存在的问题进行了探讨。     

An overview of CDMA evolution toward wideband CDMA

Third-generation mobile radio networks, often dubbed as 3G, have been under intense research and discussion recently and will emerge around the year 2000. In the International Telecommunications Union (ITU), third generation networks are called International Mobile Telecommunications-2000 (IMT-2000), and in Europe, Universal Mobile Telecommunications System (UMTS). IMT-2000 will provide a multitude of services, especially multimedia and high-bit-rate packet data. Wideband code division multiple access (CDMA) has emerged as the mainstream air interface solution for the third-generation networks. In Europe, Japan, Korea, and the United States, wideband CDMA systems are currently being standarized. This article provides a comprehensive introduction to wideband CDMA. It also provides a review of the wideband CDMA air interface proposals including WCDMA in Europe and Japan, cdma2000 in the United States, and wideband CDMA in Korea.     

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。     

The cellular phone industry in Malaysia: toward IMT-2000

Explosive growth of the cellular phone industry in Malaysia has been witnessed in the 1990s. Eight nationwide cellular phone operators with different technology bases exist in a single market. This article provides an overview of the telecommunications industry, especially the cellular phone sector, and also the activities on IMT-2000 in Malaysia     

An overview of air interface multiple access for IMT-2000/UMTS

The basis for any air interface design is how the common transmission medium is shared between users (i.e., multiple access scheme). The underlying multiple access method for all mobile radio systems is FDMA. The performance of TDMA and CDMA has been subject to vigorous debate, without any definitive conclusions. This article gives an overview of worldwide research and standardization activities related to the multiple access schemes for third-generation mobile communications systems IMT-2000 and UMTS     

The design policy for a GSM-based IMT-2000 network

The third-generation mobile network has been a topic of considerable interest worldwide and has begun to be commercialized throughout the world. The 3G mobile network has evolved from two types of 2G networks; one type has evolved from GSM and another from ANSI-41. We operate the Personal Digital Cellular network as a 2G network and have designed a GSM-based IMT-2000 network as a 3G network. This article gives our design policy for the GSM-based IMT-2000 network and the technology that enabled us to develop the network based on this policy (e.g., ATM switching in the core network). Furthermore, the foundations for 2G/3G dual network operation (e.g., number portability and succession of 2G services in a 3G network) and efficient transition from a 2G network to a 3G network are also considered.     

Future Mobile Communications Systems in Japan

A penetration rate of portable phones became more than 50% in Japan andpeople are getting to expect new kinds of services provided by new generation systems. 3rd generation IMT-2000 commercial service is to be started in the second quarter of 2001 and 4th generation systems became new research target. This paper describes new services that will be provided by IMT-2000 systems in Japan and a concept of the 4th generation system. Major technologies for 4G systems are also presented.     

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.     

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。     

IMT—2000的研究进展

本文就第三代移动通信系统ＩＭＴ－２０００研究的一些最新进展，特别是模式间融合的情况作了简要介绍。     

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。     

Deterministic channel modeling and performance simulation of microcellular wide-band communication systems

To evaluate the performance of future microcellular IMT-2000 modems, simple physical models are required, so that a number of system characteristics, such as the signal bandwidth, the antenna beamwidth, or the base station height can be accounted for at a limited computational cost. This paper describes a deterministic three-dimensional electromagnetic model, which allows simulation of the radiowave propagation for microcellular wide-band communication systems in urban areas. The model is based on a UTD ray-tracing tool and makes use of an improved mirror method. Simulated power-delay profiles are plotted against measured power-delay profiles recorded at 1.87 GHz in a street of Louvain-la-Neuve, Belgium, by means of an 80-MHz channel sounder. Despite several discrepancies, a satisfying matching is found considering three orders of reflection and single diffraction. Predictions of rms delay-spread accounting for the sounder limited bandwidth are presented. Finally, simulated and measured channels are also compared through the resulting performance of a typical IMT-2000 service in the presence of multiple access interference.     

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     

Mobile WiMAX systems: performance and evolution

Mobile WiMAX was successfully adopted by ITU as one of the IMT-2000 technologies in November 2007. Since then mobile WiMAX (a.k.a. IP-OFDMA) has officially become a major global cellular wireless standard along with 3GPP UMTS/HSPA and 3GPP2 CDMA/ EVDO. Mobile WiMAX is an OFDM-based technology available for deployment today, and new WIMAX devices come to market at much reduced cost than that of current 3G solutions. Currently over 260 service providers are deploying fixed, portable and mobile WiMAX networks in 110 countries. This article provides an overview of the mobile WiMAX system and its performance under various configurations, channel conditions, and types of data traffic. Furthermore, the article provides an overview of mobile WiMAX evolution.