• 대한전기학회논문지:시스템및제어부문D
• /
• 제49권8호
• /
• pp.481-490
• /
• 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
• /
• 제25권3A호
• /
• pp.334-341
• /
• 2000

This paper presents an analysis of the capacity, the interference of adjacent cells of a CDMA cellular system, depending on the soft handoff region and log-normal shadowing. The optimum soft handoff region is chosen by using Erlang capacity. It is shown that when the soft handoff region increases, the Erlang capacity increase due to a reduction of the interference power of adjacent cells. But if the region is increased above a certain value, there is no improvement in the system’s capacity. Furthermore as the standard deviation of the log-normal shadowing's normal distribution factor increases, the soft handoff region has to be increased linearly to achieve the same Erlang capacity.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2009년도 춘계학술대회
• /
• pp.891-894
• /
• 2009

In this paper, a scheme to evaluate the number of users in a WCDMA supporting multi-rate traffic is presented through the calculations of Erlang capacity from a derived blocking probability. It is observed that voice-data Erlang capacities have an inverse linear relationship. When the $E_b/N_o$ decreases from 4 dB to 3 dB within the outage probability of 2 % and at the voice rate of 8 kbps, the results show an increase of 8 Erlang at the data rates of 15 kbps, 4 Erlang at 30 kbps, 2 Erlang at 60 kbps, and 1 Erlang at 120 kbps respectively and an increase of the Erlang capacities through a gradual decrease of the data rates from 960 kbps to 15 kbps. So this is useful for optimizing as a reference of design for the capacity in a WCDMA system.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 1999년도 하계종합학술대회 논문집
• /
• pp.126-129
• /
• 1999

In this paper, it is assumed that a mobile radio channel is a Rayleigh distributed multipath fading channel and Erlang capacity and equivalent channel numbers are calculated for the reverse link of a imperfect power controlled DS/CDMA cellular system considering both shadowing and multipath fading. The DS/CDMA blocking probability is calculated based on a new analysis method that considers Erlang capacity and ICF(interference correction factor) using the median value of $E_{b(i)}$/ $I_{o}$ corresponding to each reverse link user. It is showed that the effect of multipath fading must not be ignored in Erlang capacity of the IS-95 DS/CDMA cellular system and the Erlang capacity is decreased according to the increase of the deviation of the imperfect power control, to the decrease of the processing gain, to the increase of the voice activity.y.

• 한국통신학회논문지
• /
• 제28권10A호
• /
• pp.788-795
• /
• 2003

We analyze the performance of a truncated power controlled CDMA(code division multiple access) cellular systems with base station antenna arrays. Erlang capacity and the channel capacity which is a maximum date rate to maintain almost error free communication are analytically derived. The numerical results show there can be a substantial increase in Erlang capacity and in channel capacity by antenna arrays incorporating with the truncated power control scheme.

• 대한교통학회지
• /
• 제21권4호
• /
• pp.103-111
• /
• 2003

본 연구는 보행자가 반대방향 도로횡단을 위한 간격을 찾기 위해 대피해 있을 수 있는 중앙분리대 대기공간이 설치되어 있는 비신호 횡단보도에서 확률적 모형을 토대로 보행자 횡단용량모형식을 개발하는 것을 목적으로 한다. 횡단보도에 접근하는 교통류의 차두시간 분포를 Erlang분포로 가정하고 간격수락이론을 이용하여 보행자 최대 통과교통량을 산출할 수 있는 방법론을 개발하였다. 분석 대상도로의 차로수는 왕복 2, 4, 6차로를 기준으로 Erlang 계수가 1, 2, 3인 분포를 사용하여 각 Erlang 계수별 모형식을 개발하였다. 모형식에 의한 보행자 용량은 접근교통량이 증가할수록 횡단가능 보행자수는 감소하고, 차로수가 커질수록 보행자용량은 감소하는 결과를 보였다. Erlang 계수는 교통량 수준과 밀접한 관계를 가지고 있으므로 보행자용량은 Erlang 계수값이 커질수록 감소하는 패턴을 나타냈다. 본 연구의 결과는 횡단보도의 보행자신호등 설치기준 및 보행자 대기공간을 제공해주는 기준으로 활용될 수 있을 것으로 판단되고, 특히 로타리교차로같이 차량중심의 연속성 진행흐름의 도로시설에서 보행자 안전시설의 설치기준으로 유용하게 사용될 수 있을 것이다.

• 한국정보통신설비학회:학술대회논문집
• /
• 한국정보통신설비학회 2007년도 학술대회
• /
• pp.327-330
• /
• 2007

This article discusses a capacity planning method in QoS-guaranteed IP networks such as BcN (Broadband convergence Network). Since IP based networks have been developed to transport best-effort data traffic, the introduction of multi-service component in BcN requires fundamental modifications in capacity planning and network dimensioning. In this article, we present the key issues of the capacity planning in multi-service IP networks. To provide a foundation for network dimensioning procedure, we describe a systematic approach for classification and modeling of BcN traffic based on the QoS requirements of BcN services. We propose a capacity planning framework considering data traffic and real-time streaming traffic separately. The multi-service Erlang model, an extension of the conventional Erlang B loss model, is introduced to determine required link capacity for the call based real-time streaming traffic. The application of multi-service Erlang model can provide significant improvement in network planning due to sharing of network bandwidth among the different services.

• 전자공학회논문지S
• /
• 제35S권3호
• /
• pp.39-46
• /
• 1998

In the FDMA and TDMA Cellular Systems, call blocking rise when frewquence slots andtime slots are used to ther users. Otherwise, in the CDMA cellular systems, call locking arises when interference level is above 10dB according to call of other users. System capacity is defined to be Erlang capacity that is the number of users when CDMA blocking probability is 1% or 2%. Users number corresponded channel number of AMPS and TDMA cellular systems. In this paper, we proposed new reuse-fraction using square of interference poser and obtained Erlang capacity for reverse link of CDMA cellular system with bit rate $R_{b}$, 9.6kbps and 14.4kbps. As a results, Erlange capacity of CDMA system have more 20.7 and 5.5 times than AMPS and TDMA system and have more form 1 to 4 Erlang thatn Viterbi and Padovani obtaned.d.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 ITC-CSCC -1
• /
• pp.125-128
• /
• 2000

In this paper, we derive forward link Erlang capacity reflecting both outage probability and blocking probability of each traffic type in mixed traffics environment. We firstly determine the number of available virtual trunks of the forward link from a circuit switching perspective. Then, capacity sharing model and generalized Erlang model are employed to derive joint Erlang capacity of various traffics types.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 ITC-CSCC -1
• /
• pp.92-96
• /
• 2000

In this paper, we propose a call admission control(CAC) scheme fer the mixed voice/data DS-CDMA systems and analyze the Er-lang capacity under the proposed CAC scheme. Voice and data traffics require different system resources based oil their Quality of Service(QoS) requirements. In the proposed CAC scheme, some system resources are reserved exclusively for handoff calls to have high priority Over new calls. Additionally the queueing of both new and handoff data traffics that are not sensitive to delay is allowed. Ar a performance measure for the suggested CAC scheme. Erlang capacity is utilized. For the performance analysis, a four-dimensional Markov chain model is developed. Erlang capacity of a practical IS-95B type system depicts, and optimum values of system parameters such as the number of reservation channels and queue lengths are found with respect to Erlang capacity. Finally, it is observed that Erlang capacity is improved more than two times by properly selecting the system parameters with the proposed CAC scheme.