• 한국산학기술학회논문지
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• 제11권12호
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• pp.5029-5035
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• 2010

본 논문은 모바일 멀티미디어 서비스를 지원하기 위하여 트랙픽 수용 용량을 극대화하기 위한 방법을 제시한다. 핸드오프 세션을 위하여, 연관된 마이크로 셀들의 수에 따라서 매크로셀의 예약 자원의 수를 동적으로 조정하는 새로운 자원 예약 방법을 제안한다. 제안된 기법은 마이크로셀에서 서비스 가능한 세션의 수를 증가시킬 수 있으며 블록킹율을 현저히 줄일 수 있었다. 따라서 제안된 시스템은 매크로셀에서 세션의 수가 증가할수록 성능이 최적화된다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1078-1081
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• 2002

In microcell or picocell mobile communication using cellular method, we suggested propagation prediction model which can accurately and rapidly interpret mobile communication propagation environment in urban, when subscriber service is done based on the main road in urban. Further, we simulated suggested propagation prediction model under the hypothesis of urban propagation environment of PCS mobile communication, analyzed receiving field strength by area within a cell, and finally suggested the optimal transmitting power and location condition of microcell or picocell mobile communication base station

• 전자공학회논문지A
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• 제33A권2호
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• pp.15-22
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• 1996

This paper presents the generalized method of the prediction of the LOS propagating characteristics in an urban microcell by using theray tracing technique. Whereas the received power is calculated by the finite number of pths, 4~10, on an urban steet, the RMS delay spread is comuted by using the sufficient rays of convergence. To take into account the infinite number of paths the technique of the numbering scheme of image antennas was presented by using the rectangular pulse. As to this the existing restriction of the finitte number of paths was relaxed. based on the method of extending the number of paths and the canyon model the received power and RMS delay spread are computed and their differences according to the number of paths are compared at the frequencies of both 1GHz and 2GHz, respectively.

• 전자공학회논문지A
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• 제33A권2호
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• pp.40-49
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• 1996

In this paper, we studied channel assignment and handover schemes for the indoor microcell systems. For efficient frequency spectrum reuse we proposed the high quality reassignment (HQR) scheme. Proposed HQR scheme tries to keep the reuse distances small by monitoring C/I of channels being used. To assign a channel for a new or handove call, the scheme checks C/I of all available channels. Then HQR assigns the channel that has C/I near the threshold value, A_TH. The scheme also checks C/I of ongoing calls and continuously reassigns a new channel when needed. It attempts handover not only when C/I gets below a handover threshold value, HO_TH, but also when C/I becomes above a high quality reassignment threshold, H_TH. The performance of the proposed HQR scheme was analyzed by a computer simulation configuraed. The performance of the scheme was also analyzed for various threshold values selected and the results are presented in this paper. The results show that HQR scheme perfomrs better than the scheme adopted for DECT.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권8호
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• pp.481-490
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• 2000

This paper analyzes interference power, Erlang capacity, the number of handoff occurrences, and call blocking probability with respect to the cell radius, the soft handoff region, and the mobile's velocity in a CDMA hierarchical cellular system. The microcell cellular system has the higher Erlang capacity than the macrocell cellular system. However, the microcell cellular system, which has a high system capacity through frequency reuse has the call blocking probability higher than macrocell cellular system. Also the interference power and the call blocking probability are decreased with the operation of soft handoff. Therefore, this paper presents the optimization of soft handoff region so as to maximize system's Erlang capacity with the low the call blocking probability according to mobile's velocity in the CDMA hierarchial cellular system.

• 한국통신학회논문지
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• 제21권2호
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• pp.394-408
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• 1996

In this paper, we classify the transfer method of overflowed traffic from microcell to macrocell in micor/macro overlaid PCS system using CDMA technology, and analyze the traffic characteristics of traffic transfer methods. Soft-handoff is charaterized by communications with a new bastation on the same CDMA frequency assignment before terminating communications with the old basestation. Therefore, soft-handoff is superior to hard-handoff with respect to Grade Of Service, but it decreases the carried traffic of system. Therefore, we analyze the effect of soft-handoff with respect to handoff area variation. In order to analyze soft-handoff effect, we resolve the probability of dewelling time in soft-handoff area, and calculates the carried traffic of microcell using this result.

• 한국전자파학회논문지
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• 제8권6호
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• pp.551-557
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• 1997

이동통신에 있어서 안테나 높이에 대한 이득은 6 dB / octave로 잘 알려져 있다. 그러나 이동통신의 전파환경은 단순하지 않고 지형지물에 따라서 변하기 때문에 안테나 높이에 대한 이득도 전파환경에 따라서 달라칠 수 있다. 이 논문은 도심지 마이크로셀 환경에서의 기지국 안테나 높이 변화에 따른 수선전력의 변화를 평탄지형과 경 사지형을 모텔로하여 이론적으로 해석한 것이다. 또한 안테나 높이 이득이 나타나기 시작하는 거리인 이득점을 사률레이션에 의해 설험적으로 구하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2007년도 하계종합학술대회 논문집
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• pp.469-470
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• 2007

We used the non-reversible hierarchical scheme and the fixed channel assignment scheme for the strategy of call processing at hierarchical cellular system. We analyzed the performance of system according to the number of channel assigned at macrocell out of the usable channel at global system. Microcell is assigned the channel excepted the channel assigned at macrocell. The more the channel was aigned at macrocell, the more decreased the blocking probability became. The blocking probability of microcell had similar trend.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2007년도 하계종합학술대회 논문집
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• pp.471-472
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• 2007

At this paper, we use non reversible hierarchical scheme and fixed channel assignment scheme at the hierarchical cellular system with macrocell and microcell for the call process strategy Using this strategy, we analyze the system performance in accordance with the various dwell time at each cell. In this simulation result, the more the dwell time is small at microcell, the more the blocking probability and the handover failure probability is low.

• 한국음향학회지
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• 제16권1호
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• pp.88-95
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• 1997

마이크로셀 환경인 개인통신망은 셀의 직경이 감소함으로써 매크로셀 환경인 셀룰라보다 더 많은 가입자를 수용할 수 있게 되었다. 이러한 환경 변화에 따라 개인통신망에 알맞은 채널 할당 기법이 필요하게 되었다. 본 논문에서는 셀루라의 채널 할당 방식을 개인통신망에 적용할 경우의 문제점을 분석하고 그러한 문제점을 극복하기 위하여 개인통신망에 알맞은 채널 할당 기법을 제안하였다. 제안된 기법의 효율성을 분석하고 다른 채널 할당 기법과 비교 평가하였다. 성능평가 파라미터는 호의 블록킹확률이다.