• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.8
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• pp.2590-2606
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• 2014

A problem related to deployment of femtocells is how to manage access of users to radio resources. On one hand, all resources of the femtocell can be reserved for users belonging to a closed subscriber group (CSG), which is a set of users defined by a femtocell subscriber. This approach, known as closed access, however, increases interference to users not included in the CSG as those users do not have a permission to access this femtocell. Contrary, resources can be shared by all users with no priority in an open access mode. In this case, the femtocell subscriber shares radio as well as backhaul resources with all other users. Thus, throughput and quality of service of the subscriber and the CSG users can be deteriorated. To satisfy both the CSG as well as non-CSG users, a hybrid access is seen as a compromise. In this paper, we propose a new approach for sharing radio resources among all users. As in common cases, the CSG users have a priority for usage of a part of resources while rest of the resources is shared by all users proportionally to their requirements. As the simulation results show, the proposed resource sharing scheme significantly improves throughput of the CSG users and their satisfaction with granted bitrates. At the same time, throughput and satisfaction of the non-CSG users is still guaranteed roughly at the same level as if conventional sharing schemes are applied.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.4
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• pp.451-455
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• 2014

In LTE (Long Term Evolution)/LTE-A (Long Term Evolution-Advanced) networks, hierarchical macro/femto-cell structure is adopted to enhance system capacity. Such a femto-cell is deployed as a Closed Subscriber Group (CSG) eNB. However, the inbound handover to CSG cell experiences longer delay than normal handover because it spends more time detecting the associated CSG cells due to its sparse deployment. Most of all the legacy UEs (User Equipments) have been implemented without considering the inbound CSG handover. Accordingly, they may not meet the performance requirements on the cell discovery described in the LTE/LTE-A standards. Therefore, in this paper, the performance of the CSG femto-cell detection is evaluated using computer simulation. The evaluation results will provide a basis to tackle the latency problem of inbound CSG handover.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2631-2633
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• 2001

This paper describes the implementation of CUG(closed user group) internet contents for high speed powerline communication subscriber network.

• 한국IT서비스학회:학술대회논문집
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• 2010.05a
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• pp.100-103
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• 2010

무선 통신의 용량 증대와 음성 지역 해소 그리고 QoS를 위하여 최근 활발하게 연구개발되고 있는 femtocell은 사용자에게는 저렴한 통신 요금과 위치 인식 서비스 그리고 위치 통지에 의한 closed subscriber group간의 가족 위치 확인같은 편리성 제공과 통신사업자에게 OPEX, CAPEX 경감 등 장점을 제공하고 있다. 한편 기존의 유비쿼터스 컴퓨팅환경하에서 주변 상황 정보를 감지하여 인지하는 context awareness에 센싱과 서비스가 동시에 이루어지는 새로운 파라다임을 제공해 주고 있어 상황인지 시스템 구축에 파라다임의 변화가 필요한 시점이다. 즉, raw data 취득, 가독 data로 변환, 고수준 상황추론, 서비스 제공 등의 시스템 구축이 휴대 단말의 응용 프로그램이나 네트워크에서 단말을 인식하여 연결된 기기들에 대해 정보 전달이 가능해져 별도의 시스템 구축 없이도 상당 부분의 상황인지 framework 기능이 가능하게 되었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.3B
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• pp.158-164
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• 2012

Heterogeneous Network and CSG cell are hot issues in the 3GPP LTE/LTE-Advanced system. In this paper, we analyze the system information measurement methods which are essential for handover to CSG cell. Since there have been no sufficient discussion about this problem, we present and analyze five possible solutions. Moreover, we propose a novel solution to reduce system information measurement delay. In the proposed Autonomous Measurement with Parallel Small Gap(AMPSG) method, the UE measures system information of neighbor cells in a parallel manner. As a result, the proposed method shows better delay performance. Therefore, the proposed AMPSG method can reduce handover delay since the UE have to measure the system information of neighbor cells before CSG handover decision.