• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.158-161
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• 2010

In the paper, the researcher has proposed to install a relay between Base Station (BS) and Mobile Station (MS) to improve receiving performance of the downlink transmission method of Long Term Evolution (LTE) system whose standards now being established by 3GPP. By setting the distance between the location of BS and the relay installed as by 500m, 1000m, and selecting OFDMA and SC-FDMA as transmission method, the researcher conducted a study to improve the receiving performance of LTE. The results from study revealed that when the location of Relay Station (RS) was closer to BS, it was better to use OFDMA at BS, and SC-FDMA at RS. On the contrary, when the distance between BS and RS was farther, it was better to use SC-FDMA at BS, and OFDMA at RS. In addition, around the center zone between the location of BS and of MS, the researcher was able to improve the receiving performance of the system by utilizing the transmission method suitable for the situation in that area.

• Electronics and Telecommunications Trends
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• v.21 no.3 s.99
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• pp.36-47
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• 2006

이동통신 시스템은 점차 고품질 및 고속의 멀티미디어 서비스를 제공하는 방향으로 가고 있다. 3GPP에서는 기존의 WCDMA 기반의 3세대 이동통신 시스템의 기술적 한계를 극복하기 위해 2004년 말에 3rd Generation Long Term Evolution(3G LTE) Plan을 발표하고, 2006년 6월까지 Technical Report 규격을 작성완료하고 2007년 6월까지 Technical Standard 작성완료를 목표로 2005년 초부터 규격 작업을 수행하고 있다. 본 고에서는 3G LTE 물리계층 및 MAC 계층의 기술 표준화 동향을 살펴본다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.15 no.3
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• pp.192-199
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• 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.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2021.06a
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• pp.260-263
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• 2021

3GPP (3rd generation partnership project)는 5G 요구 조건을 충족시키기 위해 release 16 에서 FeMBMS (further evolved MBMS)를 LTE 기반 5G MBMS 로 개선하였다. 이어서, 현재 개발 중인 release 17 에서 NR 기반의 디지털 방송을 위한 NR MBS (multimedia broadcast services)가 논의되고 있다. 본 논문에서는 LTE (long term evolution) 기반 5G MBMS (fifth generation multimedia broadcast & multicast services)와 5G NR (fifth generation new radio)의 PBCH (physical broadcast channel) 에 대한 송수신기 구조를 설명하고, 성능을 평가한다. 본 논문에서는 가산 백색 가우시안 잡음(additive white Gaussian noise: AWGN) 및 고정 환경 하에서 LTE 기반 5G MBMS 와 5G NR 에 대한 PBCH 의 성능을 비교한다.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.45-52
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• 2013

Coordinated Multi-Point (CoMP) is considered as a technology in the 3rd Generation Partnership Project(3GPP) Long Term Evolution-Advanced (LTE-A) system. In this paper, we design and analyze the performance of the Coordinated Beamforming (CB) technique, which is one major category of CoMP. We perform Monte Carlo simulations with a Heterogeneous Network (HetNet) in LTE-A, and confirm the performance through a graph of the Cumulative Distribution Function (CDF). From the simulation results, we show significant performance gain with the CoMP technique, and better performance when we apply various schemes of scheduling and precoding.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.3
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• pp.151-161
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• 2014

3GPP LTE-Advanced (Release 10) system specifies carrier aggregation (CA) to enable high data rate on using multiple frequency bands, including the variout CA-specific deployment scenarios. Considering one of those scenarios in which the different directional sector antenna is employed by each frequency band, we propose a per-carrier cell selection scheme that can improve the average throughput of the cell-edge users by allowing each user equipment (UE) to select the frequency band of the adjacent cell. Furthermore, a distributed algorithm for inter-cell copperative scheduling in this scheme is proposed to support proportional fairness among the cells. It has been shown that the proposed scheduling algorithm for the per-carrier cell selection scheme improves the cell-edge user throughput roughly by 50% over that of the conventional scheme.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.6
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• pp.8-14
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• 2012

In this paper the core technologies of LTE/LTE-Adv systems which may enable the accommodation of huge mobile traffic today are introduced and investigated in order to provide some insights for future boradband mobile services provisioning. One of the key requirements for realization of broadband mobile services is to improve the efficiency of frequency usage and also stable performance of the LTE networks is indispensible to future use. In this sense, key technological issues are summarized hereafter and the technological breakthroughs required for the optimized operation of the networks are briefly discussed.

• Electronics and Telecommunications Trends
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• v.25 no.6
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• pp.38-49
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• 2010

LTE 시스템에서 이동성 관리란 단말의 아이들 상태에서 수행되는 셀 재선택 기능과 단말의 통신중에 수행되는 핸드오버 기능을 모두 포함한다. 특히, 핸드오버 기술은 '통신중 끊김없는 서비스 보장'이라는 단순 기술형태에서 UMTS, HSPA 및 CDMA2000-1X 등 서로 다른 네트워크간의 컨버전스를 통하여 효과적인 트래픽 로드 분산 사업자의 초기 시설투자 부담 감소, 그리고 가입자의 자유로운 네트워크 선택 및 이에 따른 저렴한 요금 혜택 등 사업자와 가입자 모두에게 새로운 비즈니스 모델을 제공하는 복합 기술 형태로 진화되고 있다. 본 고에서는 LTE/LTE-Advanced 시스템에서 무선링크 측정, 타깃 셀 결정, 패킷 손실 관리, 타깃 셀로의 통신로 스위칭 등 일련의 고속 제어절차를 통하여 packet lossless-, timeless- 및 seamless- connectivity가 기능하도록 설계된 핸드오버 기술 전반을 무선 액세스 네트워크 관점에서 다룬다. 본 고에 사용된 정보 소스는 3GPP LTE 표준 문서에 기반한다.

• TTA Journal
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• s.153
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• pp.67-72
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• 2014

• TTA Journal
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• s.165
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• pp.74-80
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• 2016