• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.1
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• pp.135-139
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• 2012

A majority of 4G Mobile communication manufacturers have launched separated-type base stations composed of DU (digital unit) and RU (ratio unit). DUs are usually installed in the central office, while RUs with antennas are installed on the top of building or pole. Therefore, the allowable distance between DU and RU is very important for cell planning. In this paper, we analyze the allowable distance between DU and RU induced by closed-loop MIMO (mulitple input multiple output) technology in 4G FDD (frequency division duplexing) mobile communication systems. In conclusion, the distance limit between DU and RU is dependent on the frequency of the wireless communication, and the allowable distance is about 11 km when assuming the operating frequency is 2 GHz.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1387-1398
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• 2009

In the latest we will make a demand for the precision position estimation for the Mobile-station(MS)'s position. But, we have a lot of problems the position estimation method using the existing method. The Base-station(BS) measure a distance according to time delay waves to receive propagate from the MS and estimate the position using the existing circle equation with method to be selected BSs in close proximity the MS. It knows that happens a lot of error the estimated position and the true position. This paper propose that the method is selected round BSs to estimate for MS's position and estimated the angle using the second law of cosine. This paper demonstrate that using simulation the proposal method is a predominant method to compare with the existing method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5A
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• pp.660-667
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• 2000

This paper aims at analyzing the traffic of CDMA base station. RTD(Round Trip Delay) method, used for the study, is one of the developed tool for calculating the call setup time between the BTS(Base Station TransceiverSubsystem) and mobile station.We compare the calculated call setup time in air with the field experiments.And we suggest the RTD method for dividing the traffic of the connected repeater from that of the BTS, andwe can testify it by the experiment which analyze the difference of the received time between the base stationand the repeater including the forced delay elements.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.5
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• pp.499-505
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• 2003

In the design of mobile wireless communication system, base station location is one of the most important parameters. Designing base station location, the cost must be minimized by combining various, complex parameters. We can solve this problem by combining optimization algorithm, such as Simulated Annealing, Tabu Search, Genetic Algorithm, Random Walk Algorithm that have been used extensively fur global optimization. This paper shows the 4 kinds of algorithm to be applied to the optimization of base station location for communication system and then compares, analyzes the results and shows optimization process of algorithm.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.265-267
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• 1999

이동 통신시스템을 시뮬레이션하기 위해서는 이동 통신에서 발생되는 호의 패턴을 분석하는게 매우 중요하다. 본 논문에서는 도시지역에 설치되어 있는 기지국의 지역특성을 고려한 이동 통신 통화량을 분석하여, 제시한다. 본 논문에서는 도시를 상업, 주거, 준공업 그리고 녹지 지역으로 되어 있는 도시계획 용도지역과 이외에 특이한 호 발생 패턴이 예측되는 역과 터널 주변이라는 6개의 지역으로 구분하고, 여기에 설치되어 있는 기지국으로부터 실제 데이터를 수집하였다. 이 자료를 이용하여 기지국이 설치되어 있는 지역에 따라 이동 통신 기지국의 시간대별 통화량 분포를 분석하였으며, 하루 중 통화량이 가장 많은 최빈시간대와 통화량이 가장 적은 최번시간대를 구하였다. 또한, 구해진 각 종 결과를 시뮬레이션에 적용하기 위한 평균값 및 분포값을 제시하였다. 이 파라메터들은 이동통신 시스템의 성능 및 신뢰성을 측정하기 위한 매우 중요한 값들이다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1348-1358
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• 2000

The paper contributes to a traffic analysis for the CDMA cellular base station with repeater which are operated in a cell site. Usually the repeaters' traffic of the CDMA cellular system hardly could be separated from that of the base station because the links of the repeaters are divided from RF circuits of the base station. The paper introduces a traffic measuring method that separates the traffic of repeaters from that of the base station using time delay device. To get general results we use a single BTS(Base station Transceiver Subsystem) with three repeater as well as a single BTS with a single repeater. Then we proved that the traffic of the repeaters could separate from that of the base station clearly.

• Information and Communications Magazine
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• v.32 no.4
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• pp.64-71
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• 2015

고정 기지국 및 셀룰러 환경을 기반으로 하는 4G 네트워크 모델이 사용자가 네트워크 커버리지 안에 존재해야 서비스가 가능한 네트워크 중심인데 반해서, 5G 시스템에서는 사용자의 위치에 상관 없이 최적의 경험이 사용자를 따라 다니는 사용자 중심의 네트워크 모델이 제공되는 것을 목표로 하고 있다. 이동 개인셀 기술은 사용자 중심의 네트워크를 실현하기 위하여 사용자와 함께 이동하는 무선 백홀 기반의 초소형 기지국 및 이를 이용한 다양한 서비스를 제공하는 기술이다. 본 고에서는 이동 개인셀 기술의 여러 가지 용도와 이동 개인셀로 인한 성능 향상에 대해 논한다.

• The KIPS Transactions:PartC
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• v.13C no.2 s.105
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• pp.177-184
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• 2006

A handover is a technology that enables data transmission and receipt seamlessly while a mobile station moves from the current base station to another base station. The handover is basically classified into two types; a horizontal handover which changes a radio link only without changing a network link, and a vertical handover which changes both in heterogeneous networks. In this paper, we propose a vertical handover protocol in a dual base station which supports both of W-CDMA and WiBro networks based on SDR (Software Defined Radio), verify the rightness using a state transition diagram and a Petri-net, and evaluate the performance of the proposed protocol using NS-2 simulator.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.443-448
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• 2003

Ministry of Information and Communication(MIC) requires telecompanys to be base station sharing in order to prevent the duplicated investment and environmental destruction due to indiscreet constructions of a basestations for enlarging its own service area among telecompanys. This paper discussed the troubles of mobile communication services to be generated in common-basestation at the subway, such as factors of power obstacles, communication equipment and establishment obstacles. The content of this paper is helpful in organizing the basestation sharing of IMT-2000 and the 4th generation mobile system, and provides the basic of a higher quality service for common-service communication.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1126-1127
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• 2009

이동통신의 급속한 발전과 함께 사용자의 서비스 요구를 만족시키기 위한 femtocell 기술이 개발되고 있다. Femtocell 기지국은 적은 사용자를 대상으로 고품질의 서비스를 제공할 수 있지만, 기존 기지국에 비하여 숫자가 많고 별도의 사용자 접속 리스트를 유지한다는 점에서 확장성 측면에서 한계를 보이고 있다. 따라서, 본 논문에서는 지리적 특성과 사용자 연관성이 높은 femtocell 기지국 간 하나의 관리 영역을 가지기 위한 서비스 클러스터 구성 기법을 제안한다. 제안하는 기법은 femtocell 기지국들과 이동단말들의 상호 작용만을 통하여 수행되므로 높은 확장성을 가진다.