• Journal of Information Technology Applications and Management
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• 제20권4호
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• pp.19-31
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• 2013

There is tremendous increasing demand on spectrum resource which is boosted by spread of cloud computing and M2M telecommunication as well as smart phone and tablet PC. Recently, spectrum sharing technology has drawn attention to the spectrum policy makers as a promising way to overcome limitation of scarce spectrum resource. To succeed in commercialization of spectrum sharing technology, it is necessary to prospect the future business ecosystem of spectrum sharing and develop appropriate policies and laws at the same time along with the advance of spectrum sharing technology. The purpose of this paper is to prospect future spectrum sharing ecosystem and analyze business ecosystem of spectrum sharing with casual loop map. With the causal map and system dynamics method, it is possible to analyze feedback loops which is not limited to linear thinking and build policies which optimize positive dynamics in business ecosystem of spectrum sharing.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권11호
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• pp.3751-3774
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• 2014

With the rapid development of wireless communication, the confliction between the scarce frequency resources and the low spectral efficiency caused by the stationary spectrum sharing strategies seriously restricts the evolution of the future mobile communication. For this purpose, cognitive radio (CR) emerges as one of the most promising inventions which can overcome the spectrum shortage. As the key technology and main objective of CR, spectrum sharing can make full use of the limited spectrum, alleviate the scarcity of frequency resources and improve the system utilities, playing thereby an important role in improving the system performance of cognitive radio networks (CRNs). In this survey, the spectrum sharing in CRNs is discussed in terms of the sharing process, mainstream sharing technologies and spectrum sharing models. In particular, comparisons of different spectrum sharing strategies are concluded, as well as that of different spectrum sensing schemes in sharing procedure. Moreover, some application examples of the spectrum sharing in CRNs, such as smart grid, public safety, cellular network and medical body area networks are also introduced. In addition, our previous related works are presented and the open research issues in the field of spectrum sharing are stated as well.

• 한국IT서비스학회지
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• 제13권4호
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• pp.109-122
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• 2014

Demand of spectrum resource is tremendously increasing recently and this trend will continues in the future due to the wide spread of IT services based on cloud computing and Internet of Things technology and as well as smart devices. Recently, spectrum sharing technology has drawn attention to the spectrum policy makers as a promising way to overcome the shortage problem of scarce spectrum resource. To succeed in commercialization of spectrum sharing technology, it is necessary to prospect the future business ecosystem of spectrum sharing and develop appropriate policies and laws at the same time along with the advance of spectrum sharing technology. The purpose of this paper is to analyze casual relationships between enablers in future business ecosystem of spectrum sharing and propose policies to vitalize spectrum sharing ecosystem based on a system dynamics causal map proposed in the previous research. With the causal map and system dynamics method, it is possible to analyze feedback loops exist in the business ecosystem of spectrum sharing and build policies which optimize positive dynamics in business ecosystem of spectrum sharing. As a result, policy leverages were found in four areas; spectrum supply, spectrum demand, spectrum quality and technology, and spectrum transaction cost. For those policy leverages, 13 policies were identified and intervention timing for each policy was discussed. Finally, the promotion policies of government and market participants to vitalize spectrum sharing ecosystem were discussed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권12호
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• pp.3237-3256
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• 2012

In the context of effective usage of a scarce spectrum resource, emerging wireless communication standards will demand spectrum sharing with existing systems as well as multiple access with higher spectral efficiency. We mathematically analyze the sum throughput of a spectrum sharing space-division multiple access (SDMA) system, which forms a transmit null in the direction of other coexisting systems while satisfying orthogonal beamforming constraints. For a large number of users N, the SDMA throughput scales as log N at high signal-to-noise ratio (SNR) ((J-1) loglog N at normal SNR), where J is the number of transmit antennas. This indicates that multiplexing gain of the spectrum sharing SDMA is $\frac{J-1}{J}$ times less than that of the non-spectrum sharing SDMA only using orthogonal beamforming, whereas no loss in multiuser diversity gain. Although the spectrum sharing SDMA always has lower throughput compared to the non-spectrum sharing SDMA in the non-coexistence scenario, it offers an intriguing opportunity to reuse spectrum already allocated to other coexisting systems.

• Journal of Information Technology Applications and Management
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• 제21권4_spc호
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• pp.431-447
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• 2014

Demand of spectrum resource is tremendously increasing and this trend will continue as more IT services such as cloud computing, smart devices, Internet of Things are provided through wireless network. Recent development of spectrum sharing technology has drawn attention to spectrum policy makers as a promising way to overcome the expected spectrum shortage problem. However, technology-based solution to spectrum shortage problem may not be sustainable since the solution affect only one aspect of spectrum sharing ecosystem. To understand the whole picture of spectrum shortage problem, policies to vitalize spectrum sharing ecosystem were proposed based on the analysis of System Dynamics causal map in the previous study. This study compares and analyzes the effect of those proposed vitalization policies by using System Dynamics simulation. Among seven alternative policies, combined application of demand acceleration policy and technology development policy was found to be more effective for better utilization of spectrum. The effect of demand acceleration policy was offset when other policies are applied together except supply acceleration policy which shows better spectrum sharing.

• 한국전자파학회논문지
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• 제29권3호
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• pp.200-213
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• 2018

본 논문은 미국의 도심형 주파수 공동사용 서비스인 CBRS(Citizens Broadband Radio Service)에 대한 최근의 법제도 개정 추진현황 및 영국의 주파수 공동사용 프레임워크(framework for spectrum sharing)를 기반으로 진행되고 있는 3.8~4.2 GHz 대역에 대한 주파수 공동사용 도입방안에 대해 소개하였다. 이를 통해 다계층 사용자 구조를 갖는 주파수 공동사용 서비스 체계에서의 무선국 면허 부여 방식, 지역적 주파수 할당 방식, 적용가능 서비스 종류에 대한 최근의 논의사항을 살펴보았으며, 향후 국내에서의 주파수 공동사용 도입 시, 관련 산업 활성화를 위해 고려해야 될 것으로 판단되는 공동사용 후보채널 선정방안을 제안하였다. 이와 함께 주파수 공동사용을 위한 무선국 면허제도 도입방안을 비롯하여, 인센티브 경매 도입방안, 주파수 공동사용 적용가능 서비스에 대해 제안하였다.

• 디지털융복합연구
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• 제17권10호
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• pp.13-21
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• 2019

제한된 네트워크 자원과 불균등한 전파 자원 분배로 인해 전파자원 부족 문제와 서비스 품질 열화가 발생하고 있다. 또한, 기존 중앙집중식 전파 공유 방식은 전파 공유 활성화를 위한 근본적인 해결책이 되지 못하고 있으며 비용, 편의성, 보안성 관점에서 비효율적이다. 본 논문에서는 전파자원을 분배하고 공유할 수 있는 저비용, 고신뢰, 고효율 플랫폼으로서 블록체인 기반의 스펙트럼 쉐어링 플랫폼을 제안하고 이를 실현하기 위한 법적 쟁점을 분석하였다. 스펙트럼 쉐어링 플랫폼에서는 와이파이 AP 전파 정보와 LTE 모바일 핫스팟 전파 정보를 블록체인에 등록하고, 전파 공유자와 전파 사용자가 스마트 컨트랙트 통해 개인 간 (P2P) 전파 공유 계약을 빠르고 효율적으로 체결한다. 전파 공유에 대한 대가와 품질 관리에 대한 보상인 암호화폐는 선순환적인 전파 공유 오픈 플랫폼 생태계를 활성화할 것이며, 스펙트럼 쉐어링 플랫폼을 통해 편리하고 효율적인 공공 무선 인프라를 제공할 수 있다.

• Journal of Information Technology Applications and Management
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• 제21권4_spc호
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• pp.449-462
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• 2014

As mobile traffic is growing, the demand for spectrum is increasing but the deficiency of spectrum becomes serious as the supply is restricted essentially. For resolving the issue, spectrum sharing system is discussed from the technical and regulatory point of view, where multiple radio users occupy same frequency. In this paper, the policies and adoptions of spectrum sharing system in some countries are analyzed with a focus on TV white space and licensed shared access, which are based on unlicensed and licensed spectrum usage respectively. Some legal and regulatory plans to adopt and activate spectrum sharing in the Radio Waves Act system of Korea are proposed as well.

• 한국전자파학회논문지
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• 제24권8호
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• pp.820-830
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• 2013

스마트 장비의 보급에 따라 무선 통신 트래픽은 급격히 증가하여, 제한된 주파수 자원을 효율적으로 사용하기 위한 주파수 공동사용 정책과 주파수 공동기술에 대한 도입이 매우 필요한 상황이다. 본 연구에서는 이러한 요구에 대처하기 위하여 공공 및 국가안전 관련 지정/승인 무선국과 허가 무선국을 중심으로 공동사용 가능 주파수 대역을 발굴하였다. 발굴된 공동사용 후보 주파수 대역은 기존의 무선국 데이터베이스를 기초로 중심주파수, 대역폭, 무선국 사용 지역 등을 고려하여 검토되었다. 결과적으로 1~4.5 GHz의 주파수 대역에서 지역적으로 공동사용이 가능한 주파수 대역을 약 901 MHz 발굴하였으며, 발굴된 대역은 향후 공동사용을 통한 M2M, WiFi 서비스 등에 활용될 것으로 예상된다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2019년도 춘계학술발표대회
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• pp.82-85
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• 2019

An adaptive power control scheme is proposed for the cognitive relay networks with joint overlay and underlay spectrum sharing model. The transmit power of the secondary user is adjusted adaptively according to the spectrum sensing results and the interference channel condition. The outage probability of the secondary user is compared by Monte - Carlo simulations between the fixed power control scheme and pure overlay or underlay spectrum sharing schemes. The results show that, by employing the adaptive power control strategy, the interference probability of the secondary user to the primary user is decreased by 70 % ~ 80 % under the same outage probability. Also, the outage probability of the secondary user is reduced by 1 ~ 2 orders of magnitude under the same interference probability. Thus, the performance of the spectrum sharing is improved effectively.