• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.6A
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• pp.1008-1018
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• 2001

본 논문에서는, 트래픽으로부터 요구된 지연한계를 보장하는 스케줄링 알고리즘으로서, \"클래스별 서비스 차등제공\" 알고리즘을 제안하였다. 제안된 알고리즘은, 공평 큐잉과 우선순위 제어 개념의 절충형 패킷 스케줄링 알고리즘이다. 다수의 트래픽 클래스 환경에서, 각 클래스별 서비스 커브를 정의하며, 클래스별 지연 한계를 충족시키기 위한 각 서비스 커브의 형태, 그리고 서비스 커브간의 관계에 근거하여, 클래스별 차등 서비스를 제공한다. 또한, 동일한 클래스 내의 세션간에는 공평 큐잉을 제공함으로써, 세션별 최소한의 대역폭이 보장될 수 있도록 한다. 지연 제어를 위해 새로 정의된 변수는, 시스템 상태에 따라 그 값이 조정됨으로써, 자원의 효율적 활용을 가능하게 한다. 제안된 알고리즘은 가상적 fluid-flow 모델에서 디자인되었으며, 이를 실질적인 패킷 모드에서 구현하는 방안이 제시되었다. 아울러, 제안된 스케줄링 알고리즘에 수반되는, 결정적 형태의 지연 보장을 위한 호 수락 제어조건을 유도함으로써, 수용된 세션들의 지연 성능이 확정적으로 보장될 수 있도록 하였다.수 있도록 하였다.

• The Journal of the Korea Contents Association
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• v.6 no.9
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• pp.1-8
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• 2006

In a CDMA system, minimizing handoff calls is an important factor for user satisfaction. In this paper, we divide the cell area into two regions: normal region and soft handoff region. And we show that differentiating the guard channel numbers in those two regions make handoff calls minimized. We develop an SRN based cell model consists of normal and soft handoff region and analyze the performance of the model.

• 전자공학회논문지 IE
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• v.46 no.3
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• pp.42-47
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• 2009

In CDMA system, the call admission control method using the variable effective bandwidth concept is employed in this paper. The bandwidth for a new call and a handoff call is allocated by considering the number of mobile station being served and dynamically assigned by taking account of the blocking rate of new calls and the dropping rate of handoff calls. There is reserved resource for handoff call. In the case radio resource is insufficient, a new call and a handoff call stand by in buffer for constant time. When radio resource come about, the waiting call is allocated the resource. I analyze the performance of system according to existence and nonexistence of buffer by a simulation study.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9B
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• pp.771-777
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• 2004

In a COMA system, the capacity is variable and mainly depends on multiple access interference. The multiple access interference has a deep relationship with transmitted or received power. The capacity of COMA2000 system is considered to be limited by the forward link capacity. In this paper, we show that the forward link cell load can be represented by the total transmitted power of base station and we propose a forward link call admission control (CAC) strategy for COMA2000 system. The proposed call admission scheme adopts the rate control algorithm for data call. This call admission scheme enables the system to utilize radio resource dynamically by controlling data rate according to the cell load status, and enhance the system throughput and grade of service (GoS). quality of service(QoS) such as blocking and outage probability.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.8
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• pp.984-998
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• 1999

최근 개인 휴대 통신에 대한 관심도가 증가하면서 B-ISDN (Broadband Integrated Services Digital Network)과 같은 기존의 유선 망에서 제공하던 다양한 멀티미디어 응용 지원을 무선 망으로 확장시키기 위한 연구가 활발히 진행되고 있다. 그러나 기존의 유선 망에서는 멀티미디어 응용 지원을 위해 QoS (Quality of Service) Provisioning에 관한 많은 연구가 되어 있으나 무선 망에서는 이동성과 무선 전파의 열악한 전송으로 인해 새로운 QoS Provisioning 방법에 관한 연구가 필수적이다. 본 논문에서는 이러한 무선 망의 특수성으로 인해 발생할 수 있는 서비스의 질 저하와 강제 종료를 줄임으로써 지속적인 QoS를 보장해 주고 한정된 무선 자원을 효율적으로 사용하며 처리에 의한 오버헤드를 줄이기 위하여 다음과 같은 세 가지 방법을 제안하였다. 첫째, 핸드오프 강제 종료율을 줄이기 위하여 대역폭 예약 방법을 사용하되 특정 셀의 트래픽 특성에 맞게 또한 시간대에 따른 트래픽 특성에 따라 예약 대역폭의 양을 조절하는 적응적 대역폭 예약 방법이다. 둘째, 많은 경우 각 셀의 트랙픽 변화는 일정한 주기로 변화한다는 특성에 따라 과거의 트래픽 정보를 이용하는 예측 기반의 대역폭 예약 방법이다. 마지막으로 호의 종류, 트래픽 특성, 단말기의 이동 속도에 따라 다른 우선 순위에 의해 호 수락 제어를 수행하는 우선 순위 기반의 호 수락 제어를 제안하였다. 시뮬레이션을 통하여 기존에 제안된 방법과 성능 비교하여, 요구되는 수준의 QoS 보장과 효율적인 자원의 사용, 요구되는 처리비용의 최소화를 통해 전체 시스템의 성능 향상을 입증하였다.Abstract As interest in wireless hand-held terminals and in personal communications services increases recently, there have been broad studies on the ways to support multimedia applications provided in wired networks such as B-ISDN (Broadband Integrated Services Digital Network) in wireless networks. However, since many studies have focused on Quality of Service (QoS) Provisioning in wired networks to provide multimedia applications, new methods of QoS Provisioning are needed in wireless networks to resolve the problem of wireless channel fading and the difficulty of mobility occurred in wireless networks. This paper proposes three schemes of QoS Provisioning in wireless networks which will make continuous QoS guarantee and efficient use of limited wireless resources possible. The first scheme reserves bandwidth in proportion to the amount of real-time traffic in the neighbor cells to decrease the handoff dropping rate of delay sensitive real-time connections, adapting reserved bandwidth for efficient resource utilization. The second scheme is predictive bandwidth reservation scheme that utilizes the past handoff information. It can decrease overheads required to adapt bandwidth reservation. The last scheme is priority-based call admission control prioritizing traffic type (real-time traffic/ non-real-time traffic), connection type (new connection /handoff connection), and mobile terminal speed (fast mobile/slow mobile). Simulation results show that the proposed QoS Provisioning schemes improve the total system performance by achieving three goals - required QoS guarantee, higher bandwidth utilization and less overhead.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.6
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• pp.1-11
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• 2000

In this paper, we propose a novel control signaling protocol that efficiently controls connection setup and increases the utilization of network resources. The proposed protocol, Separated Control Signaling Protocol(SCSP), separates bearer control from call control lot WDM optical networks. The main function of call control is to check the availability of network resources such as wavelengths and receivers at destination node. Bearer control is to reserve and assign wavelengths. The signaling architecture of this protocol consists of call controller and hearer controller The call controller handles call setup and release, activates the beater controller, and manages the status of call and bearer. The bearer controller reserves wavelengths, sets up bearer, tears down bearer. and notifies the status of beater to call controller. The state transition diagrams of each controller are designed. Using control messages and related primitives, the information flows for call setup and bearer setup, hearer teardown and call release, and reaction for setup failures are described to evaluate the performance. The simulation results show that the separated control signaling protocol is superior to conventional one in terms of call blocking probability and resource utilization.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.1
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• pp.1-13
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• 2001

In this paper, we propose a new dynamic bandwidth allocation and call admission control for VBR video sources with QoS constraints to support an efficient resource management and at the same Lime to satisfy the user's quality or service requirements. For the dynamic bandwidth allocation, first the next amount of traffic is predicted using a modified adaptive linear prediction method that considers abrupt scene change effects. And then, we dynamically allocate the necessary bandwidth to each connection based on the currently provided quality degree by the network with respect to the user's QoS requirements in terms of average delay and loss ratio. For the admission control, we determine the acceptance or rejection or a new connection based on the quality satisfaction degrees of the existing connections. Simulation results show that our proposed dynamic schemes are able to provide a stable service, which well meets the user's quality requirements.

• Journal of the Korea Society of Computer and Information
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• v.5 no.4
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• pp.82-89
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• 2000

This study analyzes the cell loss probability of an ATM multiplexer with real time and non-real time bursty traffics. It is assumed that an ATM multiplexer with loss priority control for the analysis. The loss priority control uses the CLP Reld of cell header. For easy analysis and less computation. the multiplexed traffic of the ATM multiplexer was modeled by the MMDP. The ATM multiplexer is simulated by the MMDP/MMDP/l/K queueing system. From the above results, The connection admission of an ATM multiplexer with loss priority control is determined by the cell loss probability with low priority as well as the size of threshold buffer. Therefore, to increase the statistical multiplexing gain it will be good to utilize the loss priority control in order.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7B
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• pp.1268-1278
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• 1999

In this paper, we propose an analytic method for dimensioning of traffic descriptors at the leaky bucket-based UPC for VBR MPEG video traffic on ATM networks. We analytically derive cell violation probabilities at the UPC by using the proposed scene-based video traffic model, and then we show that it is possible to select sets of traffic descriptors that have the same required violation probability. For two example video traces, numerical results show that our proposed traffic descriptors dimensioning method can approximate well the simulation-based traffic control results of the real video traces. When the effective bandwidth allocation method of an ON/OFF model is used for the call admission control in the networks, we present an efficient traffic descriptor selection method by studying the allocated bandwidth to each possible traffic descriptor set.

• Journal of the Korea Society of Computer and Information
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• v.19 no.12
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• pp.81-89
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• 2014

The heterogeneous LTE-Advanced networks comprising a macrocell and femtocells can provide an efficient solution not only to extend macrocell coverage but also to deal with packet traffics increasing explosively within macrocells. Efficient resource management schemes are necessary to maintain the QoS requirements of versatile multimedia applications in LTE-Advanced networks because their service-continuity may be defected by some delay and information loss. In this paper, we propose a resource allocation method for the heterogeneous LTE-Advancedl networks overlaid with femtocells. Performances are analyzed by simulation.