• Journal of Advanced Navigation Technology
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• v.13 no.3
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• pp.372-377
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• 2009

This paper evaluates the performance of three methods for predicting resources requested by mobile's calls and a call admission algorithm based on these predicting methods respectively in wireless networks. The first method is based on Wiener prediction model and the second method is based on the MMOSPRED algorithm and the third method is based on the neural network. The proposed call admission algorithm is based on prioritized handoff call in resource allocation. The resources for future handoff calls are therefore predicted and reserved in advance, and then new calls are admitted as long as the remaining resources are sufficient. We compare their performances in terms of prediction error, new call blocking and handoff dropping probabilities by simulation. Results show that the CAC based on Wiener prediction model performs favorably due to exact resources prediction.

• Journal of KIISE:Information Networking
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• v.29 no.1
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• pp.1-14
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• 2002

The most important issue in providing multimedia traffic on a mobile computing environments is to guarantee the mobile host(client) with consistent QoS(Quality of Service). However, the QoS negotiated between the client and network in one cell may not be honored due to client mobility, causing hand-offs between cells. In this paper, a call admission control mechanism is proposed to provide consistent QoS guarantees for multimedia traffics in a mobile computing environment. Each cell can reserve fractional bandwidths for hand-off calls to its adjacent cells. It is important to determine the right amount of reserved bandwidth for hand-off calls because the blocking probability of new calls may increase if the amount of reserved bandwidth is more than necessary. An adaptive bandwidth reservation based on an MPP(Mobility Pattern Profile) and a 2-tier cell structure has been proposed to determine the amount of bandwidth to be reserved in the cell and to control dynamically its amount based on its network condition. We also propose a call admission control based on this bandwidth reservation and "next-cell prediction" scheme using an MPP. In order to evaluate the performance of our call admission control mechanism, we measure the metrics such as the blocking probability of our call admission control mechanism, we measure the metrics such as the blocking probability of new calls, dropping probability of hand-off calls, and bandwidth utilization. The simulation results show that the performance of our mechanism is superior to that of the existing mechanisms such as NR-CAT1, FR-CAT1, and AR-CAT1.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.12
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• pp.83-93
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• 2003

Differentiated service networks, based on bandwidth broker, perform the control and management of QoS provisioning for the QoS guaranteed services, However, the centralized bandwidth broker model has a scalability problem since it has centralized resource management for the admission control function of all call attempts, Therefore, in this paper, we proposea novel adaptive admission control mechanism according to the attempted call status for enhancing the scalability under the centralized bandwidth broker model in IP differentiated service networks, The proposed mechanism decouples the function of admission control from the bandwidth broker, So, the ingress edge node performs the admission control and the bandwidth broker performs the resource management and QoS provisioning, We also introduce an edge-to-edge path concepts and the ingress edge node performs the admission control under the allocated bandwidth to eachpath. The allocated bandwidth per path adaptively varies according to the status of the attempted calls, This mechanism can significantly reduce the number of communication message between the bandwidth broker and each edge node in the network and increase the bandwidth utilization via adaptable resource allocation, In this paper we study the adaptive admission control operation and show the efficient and extensive improvement through the performance evaluation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4B
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• pp.162-169
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• 2005

Network traffic measurements show that the data traffic on packet switched networks has the self-similar features which is different from the traditional traffic models such as Poisson distribution or Markovian process model. Most of the call admission control researches have been done on the performance analysis of a single network switch. It is necessary to consider the performance analysis of the proposed admission control scheme under interconnected switch environment because the data traffic transmits through switches in networks. From the simulation results, it is shown that the call admission control scheme may not operate properly on the interconnected switch even though the scheme works well on a single switch. In this parer, we analyze the cell loss probability, utilization and self-similarity of output ports of the interconnected networks switch by using shared buffer memory management schemes and propose the new call admission control scheme considering the interconnected network switches under self-similar traffic environments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6A
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• pp.458-467
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• 2009

Long Tenn Evolution (LTE) is the next generation mobile phone technology which has being standardized by the Third Generation Partnership Project (3GPP). In the existing mobile communication networks, voice traffic is delivered through circuit switched networks. In LTE, however, all kinds of traffic are transferred through IP based packet switched networks which has best-effort characteristic. Therefore, providing QoS in LTE system is difficult. In order to provide QoS in LTE, RRM is very important. Especially, in part of RRM, call admission control (CAC) performs an important function to reduce network congestion and guarantee a certain level of QoS for on-going calls. In this paper, we propose a CAC algorithm in order to provide QoS for various kinds of services in LTE system. The performance of the proposed algorithm is evaluated with various simulation environments. The results show that the proposed algorithm provides QoS through rejections of requested calls. Especially, the proposed CAC algorithm can be satisfied with packet delay requirement defined in LTE specification.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10b
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• pp.1581-1584
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• 2001

본 논문에서는 무선 셀룰러 망에서 호 수락 제어와 대역폭 예약을 위한 효율적인 기법을 제안한다. 제안된 방식에서는 각 셀에서의 핸드오프 호 절판확률을 줄이기 위해서 무선단말 사용자의 이동패턴에 대한 통계적인 정보를 이용하여 사용자에 대한 이동성을 예측하며, 이는 데이터 압축기법을 토대로 하는 허프만 알고리즘을 통해 최적화된다[1]. 제안된 이동성 예측 기법을 통해 무선단말 사용자가 이동하게 될 셀들에 대해서 핸드오프 호를 위한 대역폭이 예약되며, 호 수락 임계치를 적절하게 조절함으로써 핸드오프 호 절단률을 최소화하고, 자원이용률을 최대화시킬 수 있다. 제안된 방식이 기존의 방식에 비해 성능이 향상될 수 있는 새로운 기법을 제시한다.

• Journal of Advanced Navigation Technology
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• v.13 no.6
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• pp.901-906
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• 2009

This paper proposes a call admission control(CAC) method for wireless networks, which is based on the upper bound of a possibility distribution of handoff calls dropping rates. The possibility distribution is estimated in a fuzzy inference and a learning algorithm in neural network. The learning algorithm is considered for tuning the membership functions(then parts)of fuzzy rules for the inference. The fuzzy inference method is based on a weighted average of fuzzy sets. The proposed method can avoid estimating excessively large handoff calls dropping rates, and makes possibile self-compensation in real time for the case where the estimated values are smaller than real values. So this method makes secure CAC, thereby guaranteeing the allowed CDR. From simulation studies we show that the estimation performance for the upper bound of call dropping rate is good, and then handoff call dropping rates in CAC are able to be sustained below user's desired value.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6A
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• pp.565-572
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• 2007

3G Long Term Evolution (3G LTE) is a next generation cellular networks system capable or providing various mobile multimedia services by using OFDMA and MIMO based radio access technology. Among many differences from existing WCDMA based systems, the facts that 3G LTE uses Physical Resource Block (PRB) as its radio resources and provides all services through the PS domain make the development of new resource management schemes necessary. This paper proposes an adaptive partitioning based downlink call admission control scheme. It separates realtime call requests from non-realtime ones, specifies maximum allowable resource amounts for each type, but if the maximum is exceeded, call requests are accepted with probability proportional to remaining resource amounts. Despite the fact that such adaptive concept has been already adopted by other call admission schemes, the contributions of our paper, which are that we are able to find an efficient way to apply the proposed scheme exploiting PRB characteristics and measure the resource usage of base stations by PRB utilization and payload ratio, are still valid. When judging from simulation results in comparison with others, our scheme is able to prioritize realtime call requests over non-realtime ones, and at the same time, overall system performance is superior.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.671-676
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• 2006

차세대 이동 네트워크에서는 다양한 무선 접속 기술이 공존하게 된다. 이에 따라, 다양한 무선망을 지원하기 위한 분산방식의 호 수락 제어 구조인 SmartCAC를 제안한다. 우리는 네트워크간 정보 수집이 필요없는 분산방식을 위하여 모바일노드와 네트워크간의 상호동작을 이용한다. SmartCAC는 기본적으로 VHO call과 new call의 구분을 가능하도록 함으로써 VHO call에 handoff를 위해 예약된 채널을 사용할 수 있도록 한다. 또한, 이종망에서 네트워크 필터링을 할 수 있도록 모바일노드의 스피드를 이용한다. 이 때 효율적인 호 수락 제어 방식을 위하여 QoS 요구와 네트워크 사용에 대한 cost를 다룬다. 특히 우리는 이종망의 상태정보를 알 수 없는 모바일 노드가 네트워크의 상태정보를 받아 비교할 수 있도록 확장된 프로토콜을 제시하고, 시뮬레이션 연구에서 복잡도와 프로토콜 효율성에 따른 SmartCAC 평가를 수행하여 복잡도는 낮추고 효율성은 높이는 결과를 얻는다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.8
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• pp.2188-2195
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• 1999

This paper proposes a new call admission control scheme utilizing an inverse fuzzy vector quantizer(IFVQ) and neuralnet, which combines benefits of IFVQ and flexibilities of FCM(Fuzzy-C-Means) arithmetics, to decide whether a requested call not to be trained in learning phase to be connected or not. The system generates the estimated traffic pattern for the cell stream of a new call, using feasible/infeasible patterns in codebook, fuzzy membership values that represent the degree to which each pattern of codebook matches input pattern, and FCM arithmetics. The input to the NN is the vector consisted of traffic parameters which are the means and variances of the number of cells arriving in decision as to whether to accept or reject a new call depends on whether the NN is used for decision threshold(+0.5). This method is a new technique for call admission control using the membership values as traffic parameter which declared to CAC at the call set up stage, and this is valid for a very general traffic model in which the calls of a stream can belong to an unlimited number of traffic classes. Through the simulations, it is founded the performance of the suggested method outperforms compared to the conventional NN method.