341 research outputs found

    Development and standardization of an embedded Linux based triple-play IP settop box

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    Thesis (Master)--Izmir Institute of Technology, Electronics and Communication Engineering, Izmir, 2007Includes bibliographical references (leaves: 46-48)Text in English; Abstract: Turkish and Englishix, 57 leavesWith the recent enhancements to the delivery of IP services and of the video codecs such as h.264, transmission of television through IP-based communication systems has been a viable option. An IP settop box (IPSTB) constructs a bridge between a television set and a broadband IP network such as DSL, cable modem, powerline or wireless broadband. IPSTB brings new challenges for the system designers, especially in the areas of inherently organized home networking systems, protocols, and architectures. Future IPSTB products are candidate to converge the information and entertainment technologies. This thesis suggests newly developed device and service discovery methods for the design of an IPSTB software structure that is compatible with the Universal Plug and Play (UPnP) audio video (AV) device descriptions. At the design process, it suggests optimized communication schemes between the servers that are in the control of service providers, and the consumer IPSTBs. As a newly developed technology, since there is not any standardization for most parts of the overall IPTV system, this thesis takes proven mechanisms as basis and adapts them to the overall design that consists of the hardware drivers, middleware, and the additional programs which helps the middleware to handle the external components of the system connected via USB or serial interfaces. Being an innovative idea, we have used a control system called Virtual Bus Manager so as to communicate between the aforementioned system components. Some system components such as web browser is based on the X Windows architecture, so cross compiling the X system for the embedded platform has also been a challenge for the feasibility of the final design. Being the second part of the Triple-Play system, Voice over IP application has also been included and based on the compilation of open source software for the corresponding embedded system. Finally, the web browser itself has been based on the popular Gecko web-core that is derived from Firefox

    TABLE OF CONTENTS

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    Once you are aware of the benefits and applications of Voice over IP, it is too good to resist. Perhaps that is why vendors are flooding the market with VOIP products and services. The following paper analyzes the various issues in the evolving VOIP technology and the challenges in the development of VOIP products. It then presents the features of few VOIP Products offered by the leaders in this field, how well they handle the issues and som

    Description of Implementations of the Clinical Testbed Applications [83 pages]

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    Best effort measurement based congestion control

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    Abstract available: p.

    Video QoS/QoE over IEEE802.11n/ac: A Contemporary Survey

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    The demand for video applications over wireless networks has tremendously increased, and IEEE 802.11 standards have provided higher support for video transmission. However, providing Quality of Service (QoS) and Quality of Experience (QoE) for video over WLAN is still a challenge due to the error sensitivity of compressed video and dynamic channels. This thesis presents a contemporary survey study on video QoS/QoE over WLAN issues and solutions. The objective of the study is to provide an overview of the issues by conducting a background study on the video codecs and their features and characteristics, followed by studying QoS and QoE support in IEEE 802.11 standards. Since IEEE 802.11n is the current standard that is mostly deployed worldwide and IEEE 802.11ac is the upcoming standard, this survey study aims to investigate the most recent video QoS/QoE solutions based on these two standards. The solutions are divided into two broad categories, academic solutions, and vendor solutions. Academic solutions are mostly based on three main layers, namely Application, Media Access Control (MAC) and Physical (PHY) which are further divided into two major categories, single-layer solutions, and cross-layer solutions. Single-layer solutions are those which focus on a single layer to enhance the video transmission performance over WLAN. Cross-layer solutions involve two or more layers to provide a single QoS solution for video over WLAN. This thesis has also presented and technically analyzed QoS solutions by three popular vendors. This thesis concludes that single-layer solutions are not directly related to video QoS/QoE, and cross-layer solutions are performing better than single-layer solutions, but they are much more complicated and not easy to be implemented. Most vendors rely on their network infrastructure to provide QoS for multimedia applications. They have their techniques and mechanisms, but the concept of providing QoS/QoE for video is almost the same because they are using the same standards and rely on Wi-Fi Multimedia (WMM) to provide QoS

    Measuring And Improving Internet Video Quality Of Experience

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    Streaming multimedia content over the IP-network is poised to be the dominant Internet traffic for the coming decade, predicted to account for more than 91% of all consumer traffic in the coming years. Streaming multimedia content ranges from Internet television (IPTV), video on demand (VoD), peer-to-peer streaming, and 3D television over IP to name a few. Widespread acceptance, growth, and subscriber retention are contingent upon network providers assuring superior Quality of Experience (QoE) on top of todays Internet. This work presents the first empirical understanding of Internet’s video-QoE capabilities, and tools and protocols to efficiently infer and improve them. To infer video-QoE at arbitrary nodes in the Internet, we design and implement MintMOS: a lightweight, real-time, noreference framework for capturing perceptual quality. We demonstrate that MintMOS’s projections closely match with subjective surveys in accessing perceptual quality. We use MintMOS to characterize Internet video-QoE both at the link level and end-to-end path level. As an input to our study, we use extensive measurements from a large number of Internet paths obtained from various measurement overlays deployed using PlanetLab. Link level degradations of intra– and inter–ISP Internet links are studied to create an empirical understanding of their shortcomings and ways to overcome them. Our studies show that intra–ISP links are often poorly engineered compared to peering links, and that iii degradations are induced due to transient network load imbalance within an ISP. Initial results also indicate that overlay networks could be a promising way to avoid such ISPs in times of degradations. A large number of end-to-end Internet paths are probed and we measure delay, jitter, and loss rates. The measurement data is analyzed offline to identify ways to enable a source to select alternate paths in an overlay network to improve video-QoE, without the need for background monitoring or apriori knowledge of path characteristics. We establish that for any unstructured overlay of N nodes, it is sufficient to reroute key frames using a random subset of k nodes in the overlay, where k is bounded by O(lnN). We analyze various properties of such random subsets to derive simple, scalable, and an efficient path selection strategy that results in a k-fold increase in path options for any source-destination pair; options that consistently outperform Internet path selection. Finally, we design a prototype called source initiated frame restoration (SIFR) that employs random subsets to derive alternate paths and demonstrate its effectiveness in improving Internet video-QoE

    The 2nd Conference of PhD Students in Computer Science

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    Linking session based services with transport plane resources in IP multimedia subsystems.

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    The massive success and proliferation of Internet technologies has forced network operators to recognise the benefits of an IP-based communications framework. The IP Multimedia Subsystem (IMS) has been proposed as a candidate technology to provide a non-disruptive strategy in the move to all-IP and to facilitate the true convergence of data and real-time multimedia services. Despite the obvious advantages of creating a controlled environment for deploying IP services, and hence increasing the value of the telco bundle, there are several challenges that face IMS deployment. The most critical is that posed by the widespread proliferation ofWeb 2.0 services. This environment is not seen as robust enough to be used by network operators for revenue generating services. However IMS operators will need to justify charging for services that are typically available free of charge in the Internet space. Reliability and guaranteed transport of multimedia services by the efficient management of resources will be critical to differentiate IMS services. This thesis investigates resource management within the IMS framework. The standardisation of NGN/IMS resource management frameworks has been fragmented, resulting in weak functional and interface specifications. To facilitate more coherent, focused research and address interoperability concerns that could hamper deployment, a Common Policy and Charging Control (PCC) architecture is presented that defines a set of generic terms and functional elements. A review of related literature and standardisation reveals severe shortcomings regarding vertical and horizontal coordination of resources in the IMS framework. The deployment of new services should not require QoS standardisation or network upgrade, though in the current architecture advanced multimedia services are not catered for. It has been found that end-to-end QoS mechanisms in the Common PCC framework are elementary. To address these challenges and assist network operators when formulating their iii NGN strategies, this thesis proposes an application driven policy control architecture that incorporates end-user and service requirements into the QoS negotiation procedure. This architecture facilitates full interaction between service control and resource control planes, and between application developers and the policies that govern resource control. Furthermore, a novel, session based end-to-end policy control architecture is proposed to support inter-domain coordination across IMS domains. This architecture uses SIP inherent routing information to discover the routes traversed by the signalling and the associated routes traversed by the media. This mechanism effectively allows applications to issue resource requests from their home domain and enable end-to-end QoS connectivity across all traversed transport segments. Standard interfaces are used and transport plane overhaul is not necessary for this functionality. The Common PCC, application driven and session based end-to-end architectures are implemented in a standards compliant and entirely open source practical testbed. This demonstrates proof of concept and provides a platform for performance evaluations. It has been found that while there is a cost in delay and traffic overhead when implementing the complete architecture, this cost falls within established criteria and will have an acceptable effect on end-user experience. The open nature of the practical testbed ensures that all evaluations are fully reproducible and provides a convenient point of departure for future work. While it is important to leave room for flexibility and vendor innovation, it is critical that the harmonisation of NGN/IMS resource management frameworks takes place and that the architectures proposed in this thesis be further developed and integrated into the single set of specifications. The alternative is general interoperability issues that could render end-to-end QoS provisioning for advanced multimedia services almost impossible

    A Proposal for the Use of Wireless Technology in Healthcare

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    The annual healthcare cost in the United States is a staggering 2.6trillionUSDorover172.6 trillion USD or over 17% of the gross domestic product (GDP). Research consultancy firm McKinsey reports that remote patient monitoring of chronically ill patients alone could reduce healthcare costs by as much as 200 billion per year. Enhancements in mobile communication devices and networks make them on par or more advanced than some of the standard instruments used in healthcare today. In addition, these devices are available at much lower costs than traditional healthcare devices. Thus, leveraging these devices and wireless networks could significantly reduce the cost of healthcare delivery and expand coverage. Wireless operators have the distribution channels and marketing capability to reach the majority of the population. Wireless operators are looking to vertical industries like healthcare for future revenue growth due to saturation in the consumer market (greater than 103% penetration). Mobile operators have networks that cover over 97% of the total US population. In addition, they have a large employee base to leverage for m-health trials. With their large employee base, mobile operators have influence over large health insurers such as United Healthcare, Wellpoint, Kaiser and others. Since healthcare insurers and the Center for Medicare and Medicaid Services influence the industry through reimbursements for services, gaining their acceptance is tantamount to success
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