• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.378-380
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• 1999

무선 네트워크 환경에서는 제한된 네트워크의 대역폭과 모바일 호스트의 잦은 이동성으로 인하여 다양한 종류의 트래픽(Traffic)에 대한 Quality of Service(QoS)를 보장하는 것이 어렵다. 이러한 특징을 가지는 무선 네트워크 환경에서도 특정 종류의 트래픽(예를 들어 실시간 트래픽)에 대하여 요구된 범위내에서의 QoS가 반드시 보장되어야 한다. 본 논문에서는 이동성을 제공하는 무선 네트워크 환경에서 다양한 종류의 실시간 트래픽에 대해 QOS를 보장하는 어댑티브 레이트 얼로케이션 알고리즘을 제안한다. 제안된 레이트 얼로케이션 알고리즘은 이동성에 따라 변화하는 네트워크 자원 환경을 고려하여 각 트래픽의 QoS를 최대한 보장하는 방향으로 레이트 (Rate)를 조절한다.

• The Journal of the Korea institute of electronic communication sciences
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• v.1 no.2
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• pp.120-126
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• 2006

In this paper, we propose for improving QoS in hospital wireless network using Cellular-IP/PRC(Paging Route Cache) with Paging Cache and Route Cache in Cellular-IP. Although the Cellular-IP/PRC technology is devised for mobile internet communication, it has its vulnerability in frequent handoff environment. This handoff state machine using differentiated handoff improves quality of services in Cellular-IP/PRC. Suggested algorithm shows better performance than existing technology in wireless mobile internet communication environment. When speech quality is secured considering increment of interference to receive in case of suppose that proposed acceptance method grooves base radio station capacity of transfer node is plenty, and most of contiguity cell transfer node was accepted at groove base radio station with a blow, groove base radio station new trench lake acceptance method based on transmission of a message electric power estimate of transfer node be. Do it so that may apply composing PC(Paging Cache) and RC(Routing Cache) that was used to manage paging and router in radio Internet network in integral management and all nodes as one PRC(Paging Router Cache), and add hand off state machine in transfer node so that can manage hand off of transfer node and Roaming state efficiently, and studies so that achieve connection function at node. Analyze benevolent person who influence on telephone traffic in system environment and forecasts each link currency rank and imbalance degree, forecast most close and important lake interception probability and lake falling off probability, GoS(Grade of Service), efficiency of cell capacity in QoS because applies algorithm proposing based on algorithm use gun send-receive electric power that judge by looking downward link whether currency book was limited and accepts or intercept lake and handles and displays QoS performance improvement.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.9
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• pp.20-29
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• 2008

WLP(WiMedia Logical link control Protocol) is a protocol to support IP services on the WiMedia UWB platform. It defines that DRP needs to be employed using TSPEC parameters when the packets from upper layer transmit with QoS. However, there is no appropriate means to provide QoS when the TSPEC of the traffic is unknown. In this paper, we propose TSPEC estimation scheme to provide QoS for such unknown applications by monitoring the traffic in realtime. Also, the scheme to estimate the effective TSPEC is proposed that compensate the packet losses in the wireless environment to provide the required QoS. The performances of the proposed TSPEC estimation schemes are evaluate by simulation assuming random wireless packet loss and 1mm-ACK mechanism.

• Journal of Information Processing Systems
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• v.11 no.4
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• pp.583-600
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• 2015

Generally, the wireless network provides priority to handover calls instead of new calls to maintain its quality of service (QoS). Because of this QoS provisioning, a call admission control (CAC) scheme is essential for the suitable management of limited radio resources of wireless networks to uphold different factors, such as new call blocking probability, handover call dropping probability, channel utilization, etc. Designing an optimal CAC scheme is still a challenging task due to having a number of considerable factors, such as new call blocking probability, handover call dropping probability, channel utilization, traffic rate, etc. Among existing CAC schemes such as, fixed guard band (FGB), fractional guard channel (FGC), limited fractional channel (LFC), and Uniform Fractional Channel (UFC), the LFC scheme is optimal considering the new call blocking and handover call dropping probability. However, this scheme does not consider channel utilization. In this paper, a CAC scheme, which is termed by a uniform fractional band (UFB) to overcome the limitations of existing schemes, is proposed. This scheme is oriented by priority and non-priority guard channels with a set of fractional channels instead of fractionizing the total channels like FGC and UFC schemes. These fractional channels in the UFB scheme accept new calls with a predefined uniform acceptance factor and assist the network in utilizing more channels. The mathematical models, operational benefits, and the limitations of existing CAC schemes are also discussed. Subsequently, we prepared a comparative study between the existing and proposed scheme in terms of the aforementioned QoS related factors. The numerical results we have obtained so far show that the proposed UFB scheme is an optimal CAC scheme in terms of QoS and resource utilization as compared to the existing schemes.

• The KIPS Transactions:PartC
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• v.9C no.2
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• pp.277-282
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• 2002

In general, requirements for QoS are different according to the type of services in wire-line and wireless ATM networks, and real-time video service is more sensitive to cell transmission delay than to cell loss. Existing handoff schemes emphasizing prevention of cell loss had limitations in cell transmission delay to satisfy QoS. In this paper, a novel scheme to transmit ATM cells with low CLP(when CLP = 0) prior to others and discarding cells with high CLP(when CLF = 1) in ATM cell header among cells to be forwarded to new base station during handoffs in real-time VBR service is proposed. The proposed scheme is proven to be suitable for the satisfaction of QoS of real-time VBR service and appropriate for fast handoffs by giving high CLP value to less meaningful MPEG frames through simulations.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.215-217
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• 2005

There are two types of packet loss probabilities used in both the network layer and the physical layer within the wireless transmitter such as a queueing discard probability and transmission loss probability. We analyze these loss performances in order to guarantee Quality of Service (QoS) which is the basic of the future network. The queuing loss probability is caused by a maximum allowable delay time and the transmission loss probability is caused by a wireless channel error. These two types of packet loss probabilities are not easily analyzed due to recursive feedback which, originates as a result at a queueing delay and a number of retransmission attempts. We consider a wireless transmitter to a M/D/1 queueing model. We configurate the model to have a finite-size FIFO buffer in order to analyze the real-time traffic streams. Then we present the approaches used for evaluating the loss probabilities of this M/D/1/K queueing model. To analyze the two types of probabilities which have mutual feedbacks with each other, we drive the solutions recursively. The validity and accuracy of the analysis are confirmed by the computer simulation. From the following solutions, we suggest a minimum of 'a Maximum Allowable Delay Time' for real-time traffic in order to initially guarantee the QoS. Finally, we analyze the required service rate for each type utilizing real-time traffic and we apply our valuable analysis to a N-user's wireless network in order to get the fundamental information (types of supportable real-type traffics, types of supportable QoS, supportable maximum number of users) for network design.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.6
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• pp.89-94
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• 2009

In wireless mesh network, nodes are communicates as like as Ad-Hoc. Nodes of Wireless Mesh Network must have a good QoS and a algorithm for good path. ETX, ETT and WCETT are proposed Wireless Mesh Network routing methods. But these have Interference problem. This paper propose ETI(Expected Transmission Interference) based on ETT for good path selection. This paper show the algorithm and improved performance in simulation than other algorithms.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.4
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• pp.84-91
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• 2011

Recently, WBAN(Wireless Body Area Network) which has progressed standardization based on IEEE 802.15.6 standardization is a network for the purpose of the short-range wireless communications within around 3 meters from the inner or outer human body. Effective QoS control technique and data efficient management in limited bandwidth such as audio and video are important elements in terms of users and loads in short-range wireless networks. In this paper, for high-speed WBAN IEEE 802.15.6 standard, the dynamic allocation to give an efficient bandwidth management and weighted fair queueing algorithm have been proposed through the adjustment of the super-frame about limited data and Quality of Service (QoS) based on the queuing algorithm. Weighted Fair Queueing(WFQ) Algorithm represents the robust performance about elements to qualitative aspects as well as maintaining fairness and maximization of system performance. The performance results show that the dynamic allocation expanded transmission bandwidth five times and the weighted fair queueing increased maximum 24.3 % throughput and also resolved delay bound problem.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.496-498
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• 2004

본 논문을 다양한 사용자와 컨텐츠 그리고 무선망의 특성 변화를 고려한 무선 멀티미디어 QoS 구조를 제안한다. 제안하는 무선 멀티미디어 QoS 구조는 사용자에게 안정적인 서비스를 제공하기 위하여 시스템 자원 및 서비스 환경에서 체계적으로 설계되었다. 또한, 다양한 사용자 환경 및 요구 조건을 최대한 수용하기 위해 컨텐츠 변환 기법을 제안하고, 다양한 무선망 환경에서 효율적인 사용자 QoS 보장을 위해 무선망 상태에 따른 적응적 전송률 기법을 제안한다. 제안된 무선 멀티미디어 QoS 구조는 실제 시스템으로 구현되고 있으며, 프로토타입으로 구현된 시스템이 제안된 무선 멀티미디어 QoS 구조에 따른 컨텐츠 변환 기법 및 적응적 전송률 기법이 올바로 동작함을 보이며, 무선 멀티미디어 서비스에 대한 서비스 모델과 시스템 구조를 제시한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.3
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• pp.465-474
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• 2001

In the network with small cell radius, a mobile terminal which has large mobility should perform frequent handover. This requires that handover mechanism must be done fastly. The currently existing method for handover uses an algorithm in which the bandwidth corresponding to the adjacent cells is supposed to be allocated. However, this method leads to the problem of requiring bandwidth allocation for many-unknown cells, due to the lack of information toward moving direction in mobile terminal. In this paper, we propose an efficient dynamic bandwidth allocation algorithm for solving those problem above, based on both path rerouting handover and soft handover mechanism with wireless ATM. As for the QoS, it has been shown that proposed algorithm shows better performance than that with static bandwidth allocation algorithm.