• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.2 s.105
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• pp.110-116
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• 2006

In this paper the algorithm of a methodology for the calculation of spectrum requirements was implemented. As well, the influence of traffic distribution ratio among radio access technology groups, spectral efficiency, and flexible spectrum usage(FSU) margin was analyzed in terms of the spectrum requirements, with a view toward for future development of IMT-2000 and systems beyond IMT-2000. The ratio of the spectrum requirement to the traffic distribution ratio is approximately $1\;GHz/20\;\%$, and the spectrum requirement varies from 5 to 9 GHz. As the FSU margin increases by 1.0 dB, the total spectrum requirement decreases by 0.9 dB. The required spectrum for the market input parameter, ${\rho}=0.5$ is 801.63 MHz, while the required spectrum for ${\rho}=1.0$ is 6295.4 MHz. It can be concluded that the market input parameter is the most effective parameter in the calculation of spectrum requirements.

• Journal of Communications and Networks
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• v.4 no.4
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• pp.302-313
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• 2002

In order to facilitate and to meet the ever increasing demands for the wireless communication in the next decade and also to satisfy the high data rates for the new services, the future development of 3G (IMT2000) and systems beyond 3G (B3G) are foreseen. This article presents the need for these developments and motivations for systems beyond 3G taking into account both strategic and technological challenges to be faced. Moreover, the concepts and potential technologies involved including multiple airinterfaces, efficient spectrum allocation and utilisation for the success of systems B3G are briefly reviewed.

• Information and Communications Magazine
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• v.19 no.7
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• pp.26-32
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• 2002

• Journal of Communications and Networks
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• v.4 no.4
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• pp.314-320
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• 2002

The various sectors of the International Telecommunication Union (ITU) have been addressing the evolution of thirdgeneration and future wireless systems in the context of a comprehensive International Mobile Telecommunications 2000 (IMT-2000) project, and within the ITU’s Telecommunication Standardization Sector (ITU-T) a Special Study Group on “IMT-2000 and Beyond” has been established to address the network aspects of these emerging wireless systems. The Special Study Group (SSG) is playing a global role in this general area, in which a number of regional standards development organizations and a variety of industry forums are also active. This paper provides background information on the SSG and describes the SSG’s ongoing work addressing medium-term issues relating to convergence of fixed and mobile systems and the harmonization of evolving IMT-2000 systems. The paper also addresses related mobility management aspects.

• Journal of Communications and Networks
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• v.7 no.2
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• pp.171-177
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• 2005

This paper addresses mobility management (MM) requirements and framework for systems beyond IMT-2000 (SBI2K), based on the standardization works that has so far been done in ITU-T study group 19. We first identify the requirements for MM in SBI2K. Based on the identified MM requirements, we describe the MM framework for location management and handover management for SBI2K. We then review and analyze some of the existing IP-based MM protocols. From the analysis and comparison, we see that the existing MM schemes cannot meet all of the MM requirements for SBI2K. It is naturally concluded that further work is needed to enhance the available MM schemes SBI2K.

• Journal of Communications and Networks
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• v.7 no.2
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• pp.135-143
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• 2005

This paper presents an investigation of satellite radio access technology for beyond IMT-2000 systems. Although we could not see any active role of a satellite system in the 3G networks, satellite system will provide strong advantages in future systems for certain applications. Because a satellite link has longer round trip delay than a terrestrial link, we need technologies that would make the satellite component especially efficient. After presenting the satellite radio interface of the 3G system, we suggest several points which need to be considered in the beyond 3G systems. We also suggest a few candidate technologies with various simulation results.

• Electronics and Telecommunications Trends
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• v.18 no.1 s.79
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• pp.42-50
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• 2003

최근의 폭발적인 인터넷 사용의 증가와 또 그것과 유사한 품질의 서비스를 이동중에도 제공 받고자 하는 사용자의 요구와 음성통화 시장의 포화에 따라 무선 데이터 시장을 새로운 돌파구로 보는 제조업체 및 서비스 제공자의 노력으로 IMT-2000 서비스가 이미 진행되고 있다. 비록 2세대 디지털 셀룰러에서 IMT-2000으로의 진화가 현재 지지부진하지만, 2010년경의 데이터 사용량 예측을 참고로 할 때 새로운 시스템의 출현이 필연적이다. ITU-R SG8에서는 1999년 말까지 초기 IMT-2000 시스템에 대한 표준화 작업을 수행해왔던 TG8/1을 해체하고 2000년 이후의 위성 및 지상 부분 모두를 포함한 IMT-2000의 발전과IMT-2000 이후 시스템에 대한 비전과 목적의 정립을 위해 SG8 산하에 WP8F를 조직하여 활발하게 연구하고 있다. 본 고에서는 IMT-2000의 비전 표준화를 중심으로 하여 WP8F의 주요 표준화 동향을 살펴본다. 아울러 WP8F의 유관 기관의 활동도 함께 기술한다.

• 한국정보통신설비학회:학술대회논문집
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• 2003.08a
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• pp.149-152
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• 2003

3세대 이동통신인 IMT-2000의 표준화는 3GPP(3rd Generation Partnership Project)와 3GPP2(3rd Generation Partnership Project2)라는 글로벌한 사실표준화 단체를 구심으로 이루어지고 정보통신관련 세계 표준을 제정하는 ITU의 역할이 다소 축소되었다. 이에 ITU에서는 IMT-2000 이후의 통신시스템에 대한 표준의 제정방향을 결정하고, 권고안의 작성작업에 착수하였다. IMT-2000 이후의 통신시스템은 공식적인 용어는 아니지만 4세대 이동통신이라고도 하며, 이 개념은 2000년부터 나타나기 시작하여 현재 각 국가별로 기술개발 및 선행연구를 수행중이다. 본 논문에서는 4세대 이동통신의 개념 및 출현시점을 정의하고 4세대 이동통신 표준화의 국제 및 국내 추진현황을 살펴본 후 4세대 이동통신 시스템의 표준화 전략을 논하고자 한다.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.470-470
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• 2004

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.7A
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• pp.730-737
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• 2007

The new wireless multimedia environment is coming because of the variety of an user requirement and a traffic increase which we can not accept in the IMT-2000 present systems. To offer the wireless multimedia service the world wireless communication company which included the ITU-R is developing the standard and technique of 4G systems. We analyzed the technique criteria of the 4G wireless communication system in this paper which is based on that of WiBro System. We referred to the technique criteria of the WiBro system and deduced an occupied frequency bandwidth which is the common element of the uplink and downlink system among main wireless communication technique criteria. And we verified this through the simulation. So we proposed the occupied frequency bandwidth for 4G wireless communication in this paper.