• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.5
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• pp.37-43
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• 2009

Streaming video service over wireless and mobile communication networks has received significant interests from both academia and industry recently. Specifically, mobile WiMAX (IEEE 802.16e) is capable of providing high data rate and flexible Quality of Service (QoS) mechanisms, supporting mobile streaming very attractive. However, we need to note that streaming videos can be partially deteriorated in their macroblocks and/or slices owing to errors on OFDMA subcarriers, as we consider that compressed video sequence is generally sensitive to the error-prone channel status of the wireless and mobile network. In this paper, we introduce an OFDMA subcarrier-adaptive mobile streaming server based on cross-layer design. This streaming server system is substantially efficient to reduce the deterioration of streaming video transferred on the subcarriers of low power strength without any modifications of the existing schedulers, packet ordering/reassembly, and subcarrier allocation strategies in the base station.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6260-6268
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• 2015

In LTE-Advanced that different networks coexist, it is considered that it is actually difficult to provide service continuity with a procedural and static control method applied to the existing voice service. This paper suggests Service Self-Organization to support the service continuity effectively based on SON. It means a method in which a subscriber's terminal collects information about its current condition and base station around, and a base station, through the data collected by monitoring inner or adjacent base station, shares related data and converges, controlling service continuity on its own. In other words, as context information of mobile terminal and base station changes, set-up of related functions such as ISHO, cell selection, source allocation, load control, and QoS mapping is adapted; each function fits into the change, exchanges the process of reorganization, and interacts; these actions go toward to satisfy service continuity. Simulation results show that it provides better performances than the conventional one with the measure of resource utilization rate and outage probability.

• Journal of Broadcast Engineering
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• v.13 no.5
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• pp.696-706
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• 2008

In this paper we show the performance of the network-adaptive high-definition scalable video streaming using QWLAN board with IEEE 802.11e MAC monitoring and control. Realtime collected MAC parameters are used to determine which video data is extracted for the predicted available bandwidth. To achieve performance, extraction through R-D is proposed instead of the standard video packet extraction. It is shown through experiments that streaming video quality can be enhanced by fast adaptation to network conditions by using the proposed method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7B
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• pp.673-685
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• 2002

In this paper, we analyze the pros and cons of the fast power control to the forward link in the environments where mixed traffics of voice and data produce the transmitted/received power difference. We propose the Zone-based power control scheme that can improve the performance of the fast power control scheme in the viewpoint of the resource allocation. The proposed scheme is a mechanism that controls both the power and rate of non-realtime data traffics according to location distribution of the mobile stations. The scheme is based on the conventional fast power control scheme in the CDMA systems, and it adaptively controls the transmission rate of each data traffic. Zone-based rate control of data call brings about somewhat power margin to the call. As a result, the proposed scheme saves the power consumption of portables and reduces the amount of interference. With the proposed scheme, not only be extended the service coverage of high-rate traffic to the entire cell service coverage, but also the QoS of low-rate traffic can keep going through the service time, especially, in the situation that the amount of incoming interference is much larger. The experimental results show that the proposed scheme yields a improved performance compared with the conventional scheme in terms of the power consumption and traffic throughput of portables, especially, with the increasing number of high-rate data traffics.

• The Journal of Korean Association of Computer Education
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• v.11 no.2
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• pp.99-106
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• 2008

In this paper, we have proposed a novel re-marking strategy at tbe ingressive edge router to improve TCP fairness of DiffServ Assured Services. Our re-marking strategy introduces a configuration method of the Temporary Permitted Rate (TPR). By using this new configuration method of TPR, IN packets of greedy TCP flows are re-marked to OUT packets pertinently and constantly whenever the network traffic changes. Simulation Results show that this novel re-marking strategy can regulate the packet transmission rate of each TCP flow to the contract rate without a decrease in the link utilization.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3B
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• pp.380-389
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• 2010

Since the internet is intend to be the best effort service, the system that stream a large amount of high quality medias need a techniques to overcome the network status for implementation. In this paper, we design and implement a method that estimate quickly whether network permits the needed bandwidth of media and a method that control QoS through that. Presented system uses Relative One-Way Delay(ROWD) trend in the case of the former, and leverages temporal encoding among Scalable Video Coding(SVC) that is apt to apply real time comparatively in the case of the latter. The streaming server classifies the medias by real time to several rates and begins transmission from top-level and is reported ROWD trend periodically from the client. In case of the server reported only 'Increase Trend', the sever decides that the current media exceeds the available bandwidth and downgrades the next media level. The system uses probe packet of difference quantity of the target level and the present level for upgrading the media level. In case of the server reported only 'No Increase Trend' by the ROWD trend response of the probe packet from client, the media level is upgraded. The experiment result in a fiber to the home(FTTH) environment shows progress that proposed system adapts faster in change of available bandwidth and shows that quality of service also improves.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.643-645
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• 2010

The Internet-based multimedia services such as IPTV is being expanded with the development of technology to support the convergence of broadcasting and telecommunications technology for the control seems to be growing larger. Especially for the real-time TV broadcast multicast control technology to support the authentication and resource control, in addition to the technology services that enhance the value of technology for a variety of services in both directions seems to be developed. And, Internet-based transmission system transmit the video content for the video content delivery using RTP(Real Time Transport Protocol). Standardization body, IETF(Internet Engineering Task Force) within the RTP, according to a variety of audio and video formats only transmission format(RTP Payload Format) Establish a separate standard and scalable video content "RTP Payload Format for SVC(Switched Virtual Connection) Video" the standardization is currently processing. In this paper we are improving the quality of broadcasting and telecommunication systems, so that the upper layer by the application can react adaptively to the existing MPEG2-TS and RTP who are provided by a variety of content applied to a variety of devices consumers ETE(End- to-End) QoS(Quality of Service) for enhance the system who was designed and implemented.

• Journal of Advanced Navigation Technology
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• v.20 no.5
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• pp.440-445
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• 2016

There is a scheme where secondary users (SU) use predicted spectrum holes for primary users (PU) not to utilize for efficient utilization of the limited spectrum resources in cognitive radio networks. In this paper, we propose an adaptive call admission control framework that minimizes spectrum hopping call dropped probability (SHDP) for satisfying SU quality of service (QoS). The scheme is based on a call admission control (CAC), bandwidth prediction and adaptive bandwidth assignment. The prediction model predicts not only the number of spectrum holes, but requested bandwidth of SU spectrum hopping call, and then the CAC minimizes SHDP via an adaptive bandwidth assignment in resources not being enough for reservation. We bring Wiener prediction model to predict the resources. Simulations are conducted to compare the performance of proposed scheme with an existing, and show its ability of minimizing the SHDP.

• The Journal of the Korea Contents Association
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• v.10 no.9
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• pp.36-44
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• 2010

In this paper, we propose video quality control system(VQCS) which can control video service quality through the monitoring of end-to-end available bandwidth for video streaming service like IPTV in NGN convergence network. Various multimedia services such as video, voice and gaming service can be provided by IPTV, and these services require large amounts of bandwidth. At this time, video quality degradation like video jerkiness, block distortion and blurring is caused when network available bandwidth is insufficient. Available bandwidth monitoring method is need to stably control video streaming quality. So, we periodically calculate the amount of the packets in link and measure available bandwidth by using total length field in IP header at terminal. Scalability extractor in network selects suitable video streaming data rate based on available bandwidth and transports video streaming with adaptive data rate to prevent video quality deterioration.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.10A
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• pp.1139-1146
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• 2004

An abrupt increase of traffic-load in cellular CDMA systems can cause overload, as a result, degrade the quality of service (QoS) and the spectrum utilization due to lacking radio resources in base stations. In this paper, we propose a joint coverage and resource management (JCRM) scheme which can improve the QoS degradation and the spectrum utilization. The JCRM scheme hands over the overloaded traffic to neighboring cells by virtually reducing overloaded cell coverage and extending neighboring cell coverage, as well the scheme allocates radio resources based on the necessary handover probability. The proposed scheme can be applied to the existing cellular CDMA systems as well as adaptive coverage management schemes for next generation mobile communication systems.