• ETRI Journal
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• v.36 no.1
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• pp.31-41
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• 2014

The heterogeneous network (HetNet) has been discussed in detail in the Long-Term Evolution (LTE) and LTE Advanced standards. However, the standardization of High-Speed Packet Access HetNet (HSPA HetNet) launched by 3GPP is pushing at full steam. Interference coordination (IC), which is responsible for dealing with the interference in the system, remains a subject worthy of investigation in regard to HSPA HetNet. In this paper, considering the network framework of HSPA HetNet, we propose a quasi-distributed IC (QDIC) scheme to lower the interference level in the co-channel HSPA HetNet. Our QDIC scheme is constructed as slightly different energy-efficient non-cooperative games in the downlink (DL) and uplink (UL) scenarios, respectively. The existence and uniqueness of the equilibrium for these games are first revealed. Then, we derive the closed-form best responses of these games. A feasible implementation is finally developed to achieve our QDIC scheme in the practical DL and UL. Simulation results show the notable benefits of our scheme, which can indeed control the interference level and enhance the system performance.

• Information and Communications Magazine
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• v.28 no.8
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• pp.10-17
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• 2011

3GPP($3^{rd}$ Generation Partnership project)는 3세대 이동통신인 UMTS(Universal Mobile Telecommunication System)의 초기 표준화 이후 HSPA(High Speed Packet Access), MBMS(Multimedia Broadcast Multicast Service) 등의 기술 개발로 UMTS시스템을 지속적으로 발전시켜 왔다. 그리고, 최근 새로운 무선 접속 기술을 기반한 LTE(Long Term Evolution)시스템에 대한 표준화를 완료하고 ITU-T(International Telecommnunications Union-Radio)의 IMT-Advanced 요구사항을 만족하는 LTE-Advanced 시스템에 대한 연구를 진행하고 있다. 한편 LTE-Advanced 표준의 목표인 무선 전송속도를 한층 더 높이고, 단위비용(cost per bit)을 더욱 낮추고, 셀 커버리지 및 용량을 확대하기 한 저출력의 피코셀, 펨토셀, 무선중계기들을 이용하여 실내외의 소규모 영역을 서비스하도록 하는 heterogeneous network에 대한 국제 표준이 활발히 논의되고 있다. 그러나 여러 셀이 혼재하는 경우 셀들간의 신호 간섭이 발생하여 사용자의 통신 품질이 크게 저하될 우려가 있다. 본 고에서는 heterogeneous network 와 관련하여 국제 표준 LTE-Advanced에서 논의되고 있는 간섭 제어 기법에 대해 소개한다.

• Journal of Advanced Navigation Technology
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• v.13 no.4
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• pp.490-502
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• 2009

This monograph details the development of communication UAV(Unmanned Aerial Vehicle) in combined modems of HSDPA with Wibro by using two kinds of mobile network. In order to apply mobile network which is currently serviced to a UAV, it is necessary to solve some problems : insurance of wide coverage based on the range of the UAV, electrical transmission of extensive image data for UAV for watching and scouting, security of stable communication environment is related to network traffic. This paper proposes those difficulties to be solved by application of correspondence system to mobile network. The proposed system consists of two parts; HSDPA part and Wibro part. The use of those can not only secure wide range of coverage but also transmit huge data. Furthermore, through utilizing them along with two kinds of mobile network, stable communication environment can be built up. All of these effects can be confirmed by experimentations and simulations.