• Journal of Communications and Networks
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• v.13 no.3
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• pp.286-297
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• 2011

A novel converged optical network unit (ONU)-base station (BS) architecture has been contemplated for next-generation optical-wireless networks. It has been demonstrated through high quality studies that data traffic carried by both wired and wireless networks exhibit self-similar and long range dependent characteristics; attributes that classical teletraffic theory based on simplistic Poisson models fail to capture. Therefore, in order to apprehend the proposed converged architecture and to reinforce the provisioning of tightly bound quality of service (QoS) parameters to end-users, we substantiate the analysis of the QoS behavior of the ONU-BS under self-similar and long range dependent traffic conditions using custom queuing which is a common queuing discipline. This paper extends our previous work on priority queuing and brings novelty in terms of presenting performance analysis of the converged ONU-BS under realistic traffic load conditions. Further, the presented analysis can be used as a network planning and optimization tool to select the most robust and appropriate queuing discipline for the ONU-BS relevant to the QoS requirements of different applications.

• Journal of KIISE
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• v.42 no.10
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• pp.1268-1279
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• 2015

In order to manage a large number of devices connected to the Internet of Things (IoT), the Internet Engineering Task Force (IETF) proposed the IPv6 Routing Protocol for Low Power and Lossy Networks (RPL). The route of the RPL network is generated through the use of an Objective Function (OF) that is suitable for the service that is required for the IoT network. Since the route of the RPL network is conventionally simply chosen only by considering the link quality between the nodes, it is sensible to seek an OF that can also provide better Quality of Service (QoS). In previous studies, the end-to-end delay might possibly be sub-optimal because they only deal with problems related to the reduction of energy consumption and not to the link quality on the path to the sink node. In this study, we propose a scheme that reduces the end-to-end delay but also gives full consideration to both the quality on the entire route to the destination and to the expected lifetime of nodes with bottlenecks from heaped traffic. Weighting factors for the proposed scheme are chosen by experiments and the proposed scheme can reduce the end-to-end delay and the energy consumption of previous studies by 20.8% and 10.5%, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10B
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• pp.630-638
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• 2005

As real-time media applications based on IP multicast networks spread widely, the end-to-end QoS (quality of service) provisioning for these applications have become very important. To guarantee the end-to-end QoS of multi-party media applications, it is essential to monitor the time-varying status of both network metrics (i.e., delay, jitter and loss) and system metrics (i.e., CPU and memory utilization). In this paper, targeting the multicast-enabled AG (Access Grid) group collaboration tool based on multi-Party real-time media services, a hybrid monitoring scheme that can monitor the status of both multicast network and node system is investigated. It combines active monitoring and passive monitoring approaches to measure multicast network. The active monitoring measures network-layer metrics (i.e., network condition) with probe packets while the passive monitoring checks application-layer metrics (i.e., user traffic condition by analyzing RTCP packets). In addition, it measures node system metrics from system API. By comparing these hybrid results, we attempt to pinpoint the causes of performance degradation and explore corresponding reactions to improve the end-to-end performance. The experimental results show that the proposed hybrid monitoring can provide useful information to coordinate the performance improvement of multi-party real-time media applications.

• Journal of Information Processing Systems
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• v.10 no.2
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• pp.176-192
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• 2014

The realization of Wireless Multimedia Sensor Networks (WMSNs) has been fostered by the availability of low cost and low power CMOS devices. However, the transmission of bulk video data requires adequate bandwidth, which cannot be promised by single path communication on an intrinsically low resourced sensor network. Moreover, the distortion or artifacts in the video data and the adherence to delay threshold adds to the challenge. In this paper, we propose a two stage Quality of Service (QoS) guaranteeing scheme called Prioritized Multipath WMSN (PMW) for transmitting H.264 encoded video. Multipath selection based on QoS metrics is done in the first stage, while the second stage further prioritizes the paths for sending H.264 encoded video frames on the best available path. PMW uses two composite metrics that are comprised of hop-count, path energy, BER, and end-to-end delay. A color-coded assisted network maintenance and failure recovery scheme has also been proposed using (a) smart greedy mode, (b) walking back mode, and (c) path switchover. Moreover, feedback controlled adaptive video encoding can smartly tune the encoding parameters based on the perceived video quality. Computer simulation using OPNET validates that the proposed scheme significantly outperforms the conventional approaches on human eye perception and delay.

• The Journal of Information Technology
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• v.8 no.3
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• pp.131-142
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• 2005

The principles on which the Internet was designed and has evolved were first laid out in an explicit way 20 years age. The basic principle is that in layered communications network such as the Internet, functions should always be implemented at the end systems whenever the option exists. This applies to all functions that can be implemented either in the network or at the end systems. End-to-end arguments have recently been reexamined as the Internet and its uses have evolved, and a new set of requirements has begun to emerge. In addition to these, it add a new, and perhaps more important, requirement to this list in the case of heterogeneous networks: the proliferation of unpredictable wireless networks. Wireless networks must cope with dynamic link conditions not present in wired infrastructures, which place a heavy burden on quality of service management solutions. Managing QoS in the face of constantly changing operating conditions demands dynamic management approaches that span multiple layers in the protocol stack. Such as cross-layer design approaches have recently received attention in the context of cellular and mobile special networks. This article introduce the notion of network predictability and describe its relationship to achievable QoS. This relationship is used to propose a framework for cross layer design that can be used to guide development efforts and direct investment decisions for future networks.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.10
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• pp.59-66
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• 2003

We propose the novel optical burst switching scheme to guarantee a minimum bandwidth for multiple classes. To date, QoS studies on OBS network are capable of differentiating two classes, but have difficulties in providing a minimum bandwidth lot several classes because of lower classes' collision with the highest class bursts in the networks. To solve that problem, in our proposed scheme we assign time zones in a data channel for each class periodically, making one burst have top priority at least its zone. Also, the new burst assembling algorithm, as well as the way of managing data channel, is necessarily proposed to coordinate with the proposed OBS scheme. Through the evaluation, we show that the worst-case end-to-end delay is small enough and the received bandwidth of the lower classes is still assured regardless of the traffic load of the highest class.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1B
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• pp.34-44
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• 2003

As the recent rapid development of internet technology and the wide spread of multimedia communications, massive increase of network traffic causes some problems such as the lack of network paths and the bad quality of service To resolve these problems, this paper presents a web-based traffic control system which supports QoS of realtime packet transmission for the multimedia communication The traffic control system presented in this paper applies the integrated service model and provides QoS of packet transmission by means of determining the packet transmission rate according to the policies of network manager and the optimal resource allocation considering the end-to-end traffic load It also provides QoS for the realtime packet transmission through the admission controller and the packet scheduler by the modified $WF^2Q^+$ algorithm support asynchronous and class-based queuing.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.6
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• pp.672-686
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• 2002

현재 단대단(End-to-End) 비디오 서비스의 질을 높이기 위해 많은 연구가 각 계층별로 진행되고 있다. 전송계층에서의 오류 제어(Error Control), 네트워크계층에서의 QoS (Quality of Service)모델, 표현 및 응용계층에서의 오류 강인성(Error resilience)/오류 은닉(Error concealment) 등이 연구 개발되고 있다. 그러나 계층 간의 연관성이 높은 부분에서의 통합을 통한 성능향상에 관한 연구는 그 필요성과 효율에 비해 아직도 미흡하다. 본 논문은 QoS 서비스 모델하에서의 적응적 FEC(Forward Error Correction) 적용 및 우선순위에 따른 비디오패킷(VP ,VideoPacket)을 통하여 효율적인 계층화 비디오 스트리밍을 단대단 QoS성능의 향상에 관점을 맞추어 제안한다. 제안하는 방식은 최소 화질 보장과 같은 효율에서 보다 적은 가격에서의 서비스를 제공할 수 있다. 이를 위하여 통합형 서비스(IntServ, IS, Integrated Service) 의 자원예약을 사용하는 방법과 높은 가격의 자원 예약을 사용하지 않는 차별화 서비스(DiffServ, DS, Differentiated Service)를 적용했으며 이에 보장형 서비스의 특징을 공통을 가지기 위해 계층화 FEC를 적용하였으며 적절한 가격의 조절을 위하여 비디오패킷을 통한 데이터 분할을 적용하였다. 본 논문은 또한 최종 사용자의 만족도를 PSNR(Picture Signal to Noise Ration)과 PSNR에서 표현하지 못하는 부분의 평가를 위해 손상프레임율(DFR, Damaged Frame Ratio)과 오류프레임율(EFR,Error Frame Ratio)을 제안 이를 통해 평가하고자 한다. 제안하는 방식의 실험 결과는 비디오 코딩계층과 전송 계층, 네트워크 계층의 결합된 성능이며 이는 또한 화질의 개선뿐만 아니라 사용자의 가격문제에 대하여서도 비교 분석하였다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.1-12
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• 2008

The multimedia streaming service in NGN architecture is not only to deliver video streaming (VoD, Broadcasting TV, etc.) but also to provide new services and service bundles, such as Triple Play (IPTV + VoIP + Internet). Among these services, Internet Protocol Television (IPTV) is becoming a convergence of communication, content, computing, as well as an integration of broadcasting and telecommunication services. In this paper, we addresses enhanced IPTV management scheme aspect of E2E from Home Network to Head End Center over NGN to support efficient service management with a full quality of service (QoS) guarantee.

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.3
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• pp.158-167
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• 2017

Internet-based social and interactive video applications have become major constituents of the envisaged applications for next-generation multimedia networks. However, inherently dynamic network conditions, together with varying user expectations, pose many challenges for resource allocation mechanisms for such applications. Yet, in addition to addressing these challenges, service providers must also consider how to mitigate their operational costs (e.g., energy costs, equipment costs) while satisfying the end-user quality of service (QoS) expectations. This paper proposes a heuristic solution to the problem, where the energy incurred by the applications, and the monetary costs associated with the service infrastructure, are minimized while simultaneously maximizing the average end-user QoS. We evaluate the performance of the proposed solution in terms of serving probability, i.e., the likelihood of being able to allocate resources to groups of users, the computation time of the resource allocation process, and the adaptability and sensitivity to dynamic network conditions. The proposed method demonstrates improvements in serving probability of up to 27%, in comparison with greedy resource allocation schemes, and a several-orders-of-magnitude reduction in computation time, compared to the linear programming approach, which significantly reduces the service-interrupted user percentage when operating under variable network conditions.