• International Journal of Fuzzy Logic and Intelligent Systems
• /
• 제15권3호
• /
• pp.192-199
• /
• 2015

Heterogeneous cellular networks are gaining momentum in industry and the research community, and are attracting the attention of standard bodies such as 3GPP LTE and IEEE 802.16j, whose objectives are to increase the capacity and coverage of cellular networks. In this article, we provide an overview of expansion strategies, optimal locations of base stations with different characteristics, and radio-planning models.

• 전자통신동향분석
• /
• 제34권6호
• /
• pp.1-16
• /
• 2019

The paper presents five strategic opinions for promoting the fourth industry revolution through the supply of 5G additional frequency. The assessments are on the basis of 5G frequency utilization technologies and services, with reference to 3GPP 5G New Radio standards, after investigating the domestic 1G, 2G, 3G, 4G, and 5G mobile communication services as well as the use of mobile radio frequency and spectrum. The presented opinions contain the frequency supply of contiguous-wide bandwidth channels, harmonized frequency supply between licensed and unlicensed spectrum, the existing 4G frequency recycle for increasing 5G coverage and capacity, balance frequency supply in the multi-band for 5G services, and the development of 5G vertical frequency for industry. The aim is that the presented five strategic opinions can offer guidance for the upcoming plan of domestic 5G additional frequency supply.

• 디지털산업정보학회논문지
• /
• 제17권4호
• /
• pp.31-42
• /
• 2021

In the modern era, radio wave analysis is necessary for various fields of engineering, and interpretation of this is also indispensable. Self-driving cars need multiple different electronic components, and thus accurate and fast electromagnetic simulator for this kind of complex radio environment is required for self-driving simulations. Accordingly, the demand for self-driving simulators as well as existing electromagnetic analysis software has increased. This paper briefly describes the characteristics of numerical analysis techniques for electromagnetic analysis, self-driving simulation software, and conventional electromagnetic simulation software and also summarizes the characteristics of each software. Finally, the verification of the result from in-house code compared to HFSS is demonstrated.

• 디지털산업정보학회논문지
• /
• 제14권4호
• /
• pp.87-92
• /
• 2018

One of the problems with the base station equipment is that there is a large difference between the replacement time of the hardware equipment such as the base station equipment and the radio access equipment, and the evolution period of the communication standard. Therefore, the base station communication platform must be flexible enough to handle the evolving communication standards after purchase. Recent research on reconfigurable communications platforms has focused on the efficient architecture of the communications platform to meet these requirements through software downloads while still using existing hardware. This paper presents a prototype of a base station communications platform based on the ETSI standard reconfigurable architecture. The communication platform presented in this paper is implemented as an ETSI standard reconfigurable architecture using a general-purpose DSP (Digital Signal Processor). In the implemented prototype, we verify the real-time feasibility of communication protocol updates through software reconfiguration.

• 한국전자거래학회지
• /
• 제14권4호
• /
• pp.267-286
• /
• 2009

자동차부품산업에 속한 대부분의 기업은 완성차 조립을 위한 공급기업과의 협력에 있어 공급사슬관리시스템을 필요로 하고 있다. 자동차부품산업은 1차, 2차, 3차 공급업체와 같은 계층적 구조의 산업 특성을 가지고 있다. 최근 RFID 기술을 적용한 새로운 구현사례가 통합된 정보시스템 구현이 요구되는 다양한 영역에서 나타나고 있다. 특히 자동차부품산업의 공급사슬환경은 유비쿼터스환경으로 전환되고 있다. 자동차부품산업에 속한 대부분의 기업은 비즈니스 프로세스의 단축, 거래정보의 공유, 그리고 거래당사자간의 협업관계를 증진하기 위해 RFID기반의 공급사슬관리 구현에 관심이 높다. 본 연구는 제품의 입고, 출고, 재고관리와 같은 자동차부품산업의 물류분야에 RFID 기술을 구현하고자 한다. 연구의 목적은 유비쿼터스 컴퓨팅환경에서 u-SCM 시스템에 적용된 RFID를 활용하여 공급사슬네트워크의 협업관계를 증진하기 위한 것이다. 본 논문의 기여는 UML 기법을 적용하여 RFID기반의 SCM 시스템을 설계하고 구현함으로써 기존 프로세스를 새로운 프로세스로 전환하는 새로운 시스템 접근방안을 제안하는 것이다.

• Journal of information and communication convergence engineering
• /
• 제9권3호
• /
• pp.251-255
• /
• 2011

In this paper, we investigate an adaptive cognitive radio (CR) scheme where a sensing duration and a detection threshold for spectrum sensing are adaptively determined according to the channel condition in a fading channel. We optimize the sensing duration and detection threshold of a secondary user to maximize the performance of the secondary user guaranteeing a primary user's secure communication. In addition, we analyze the effect of channel fading on the optimization of the sensing duration and detection threshold. Our numerical results show that the performance of the adaptive CR scheme can be drastically improved if a secondary user can take the advantage of channel information between primary and secondary users.

• Journal of electromagnetic engineering and science
• /
• 제9권2호
• /
• pp.53-60
• /
• 2009

Remarkable developments in the electric and electronic industry have given people's daily life much more convenience and abundance. However, in electrical communication, or electric and electronic fields, making electrical and electronic devices more functional, more integrated, and faster have put electromagnetic interference(EMI) into more complex forms, and lots of problems such as interruption, malfunction, or interference by noise between electrical communication systems occurs every day. In this research, the electromagnetic compatibility(EMC) filter in the high powered breaker was designed and fabricated as a counter measure. The filter attenuated noise more than 20${\sim}$50 dB in the range of 10 MHz${\sim}$1.5 GHz. And, when the electric fast transient(EFT) of 4 kV in the level 4 of IEC 61000-4-4 was induced, it was soon suppressed to 600 V.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제8권11호
• /
• pp.3837-3859
• /
• 2014

Vehicular Ad hoc Networks (VANET) becomes more popular in industry, academia and government. However, Typical VANET is challenged by high speed mobility and insufficient spectrum resources over congested scenarios. To address those serious problems, some articles have introduced Cognitive Radio (CR) technology into VANET and formed CR-VANET. In this article, we propose an overview of CR-VANET by exploring different architectures and features. Moreover, we provide taxonomy of state-of-the-art papers in this emerging field and the key articles are well analyzed respectively. In addition, we illustrate both research and application frameworks of CR-VANET based on our works, and propose some open research issues for inspiring future work.

• 기술경영경제학회:학술대회논문집
• /
• 기술경영경제학회 2005년도 제26회 동계학술발표회 논문집
• /
• pp.124-139
• /
• 2005

In the early stage, the radio communication industry was widely accepted as a monopoly industry, so it has been controled and managed by government. But the advanced technology in Information and Technology industry has led constant increase of demand and dramatic change of communication market. Furthermore it is expected that frequency resource is to be short by market change due to wire-wireless integration. That is why the effort to utilize and manage limited frequency resource efficiently is being executed around the world. Not only newly developing and allocating the spectrum but also reallocating the existing spectrum important are, since transforming inefficiently used existing spectrum to new service can increase producer's surplus and social welfare. The economic approach to valuate the spectrum and spectrum usage right is necessary different from the traditional cost based approach, and through this approach I expect active transaction of spectrum. In this paper the real option methodology is used for valuation of spectrum, considering spectrum user's option right based on future revenue. In detail, the matter of withdrawing and reallocating the existing analog radio broadcasting spectrum is evaluated in this paper, The digitalization of a broadcasting service is widely spreaded around the world in terms of technology and service utility, and analog TV broadcasting has already been decided to be transformed to digital TV broadcasting. It was planned to convert analog radio broadcasting to DAB service before adopting DMB service, but nowadays this issue is not on the table anymore. However if the increasing demand of digital voice and broadcasting service is considered, this kind of research to valuate a spectrum is needed urgently. The result of this research shows that when the redeployment of spectrum is done, social welfare will increases. The point of the reallocation time and value are suggested by the monte carlo simulation through ROVM. In this paper, I use real option to valuate the spectrum and provide the point of the reallocation time and reasonable guideline, and moreover, the suitable information of this paper is expected to reduce risk and loss in policy practice.

• 한국통신학회논문지
• /
• 제1권1호
• /
• pp.7-14
• /
• 1976

電波通信에 관한 法源이며 法典인 國際電氣通信協約은 電波通信에 관하여 人文, 社會 및 自然의 各系科學的 要素가 有機的으로 複合한 綜合科學이라는 것을 明示하고 있고 國際電氣通信聯合은 이 原理와 科學性에 立脚하여 國際協力을 위한 法理念과 그에 基礎한 諸般規制를 立法 施行하고 있다. 이 法理念과 各種規制의 目標는 超領域的인 世界平和와 人類福祉를 指向하고 있어 恰似 UN憲章과 世界人檢宣言의 理念과도 방불하며 다른 한편에서는 國際通信法의 制定歷史上, 오히려 UN憲章보다 先行되고 있는 理念이기도 하다. 따라서 電波通信에 관한 學術硏究와 敎育訓練은 勿論이고 그밖에 이에 관계되는 立法, 行政, 産業 등 모든 關係領域에서는 이 科學性과 超領域性을 基盤으로 모든 試圖가 行하여지지 않으명 아니되는 것이다.