87 research outputs found
Quality of Service Controlled Multimedia Transport Protocol
PhDThis research looks at the design of an open transport protocol that supports a range of
services including multimedia over low data-rate networks. Low data-rate multimedia
applications require a system that provides quality of service (QoS) assurance and flexibility.
One promising field is the area of content-based coding. Content-based systems use an array
of protocols to select the optimum set of coding algorithms. A content-based transport
protocol integrates a content-based application to a transmission network.
General transport protocols form a bottleneck in low data-rate multimedia
communicationbsy limiting throughpuot r by not maintainingt iming requirementsT. his work
presents an original model of a transport protocol that eliminates the bottleneck by
introducing a flexible yet efficient algorithm that uses an open approach to flexibility and
holistic architectureto promoteQ oS.T he flexibility andt ransparenccyo mesi n the form of a
fixed syntaxt hat providesa seto f transportp rotocols emanticsT. he mediaQ oSi s maintained
by defining a generic descriptor. Overall, the structure of the protocol is based on a single
adaptablea lgorithm that supportsa pplication independencen, etwork independencea nd
quality of service.
The transportp rotocol was evaluatedth rougha set of assessmentos:f f-line; off-line
for a specific application; and on-line for a specific application. Application contexts used
MPEG-4 test material where the on-line assessmenuts eda modified MPEG-4 pl; yer. The
performanceo f the QoSc ontrolledt ransportp rotocoli s often bettert hano thers chemews hen
appropriateQ oS controlledm anagemenatl gorithmsa re selectedT. his is shownf irst for an
off-line assessmenwt here the performancei s compared between the QoS controlled
multiplexer,a n emulatedM PEG-4F lexMux multiplexers chemea, ndt he targetr equirements.
The performanceis also shownt o be better in a real environmentw hen the QoS controlled
multiplexeri s comparedw ith the real MPEG-4F lexMux scheme
Telecommunications Networks
This book guides readers through the basics of rapidly emerging networks to more advanced concepts and future expectations of Telecommunications Networks. It identifies and examines the most pressing research issues in Telecommunications and it contains chapters written by leading researchers, academics and industry professionals. Telecommunications Networks - Current Status and Future Trends covers surveys of recent publications that investigate key areas of interest such as: IMS, eTOM, 3G/4G, optimization problems, modeling, simulation, quality of service, etc. This book, that is suitable for both PhD and master students, is organized into six sections: New Generation Networks, Quality of Services, Sensor Networks, Telecommunications, Traffic Engineering and Routing
Technology 2002: The Third National Technology Transfer Conference and Exposition, volume 2
Proceedings from symposia of the Technology 2002 Conference and Exposition, December 1-3, 1992, Baltimore, MD. Volume 2 features 60 papers presented during 30 concurrent sessions
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Analysis and improvement of medium access control protocols in wireless networks. Performance modelling and Quality-of-Service enhancement of IEEE 802.11e MAC in wireless local area networks under heterogeneous multimedia traffic.
In order to efficiently utilize the scarce wireless resource as well as keep up
with the ever-increasing demand for Quality-of-Service (QoS) of multimedia
applications, wireless networks are undergoing rapid development and dramatic
changes in the underlying technologies and protocols. The Medium Access Control
(MAC) protocol, which coordinates the channel access and data transmission of
wireless stations, plays a pivotal role in wireless networks.
Performance modelling and analysis has been and continues to be of great
theoretical and practical importance in the design and development of wireless
networks. This research is devoted to developing efficient and cost-effective
analytical tools for the performance analysis and enhancement of MAC protocols in
Wireless Local Area Networks (WLANs) under heterogeneous multimedia traffic.
To support the MAC-layer QoS in WLANs, the IEEE 802.11e Enhanced Distributed
Channel Access (EDCA) protocol has proposed three QoS differentiation schemes
in terms of Arbitrary Inter-Frame Space (AIFS), Contention Window (CW), and
Transmission Opportunity (TXOP). This research starts with the development of
new analytical models for the TXOP scheme specified in the EDCA protocol under
Poisson traffic. A dynamic TXOP scheme is then proposed to adjust the TXOP
limits according to the status of the transmission queue. Theoretical analysis and
simulation experiments show that the proposed dynamic scheme largely improves
the performance of TXOP. To evaluate the TXOP scheme in the presence of
ii
heterogeneous traffic, a versatile analytical model is developed to capture the traffic
heterogeneity and model the features of burst transmission. The performance results
highlight the importance of taking into account the heterogeneous traffic for the
accurate evaluation of the TXOP scheme in wireless multimedia networks.
To obtain a thorough and deep understanding of the performance attributes of
the EDCA protocol, a comprehensive analytical model is then proposed to
accommodate the integration of the three QoS schemes of EDCA in terms of AIFS,
CW, and TXOP under Poisson traffic. The performance results show that the TXOP
scheme can not only support service differentiation but also improve the network
performance, whereas the AIFS and CW schemes provide QoS differentiation only.
Moreover, the results demonstrate that the MAC buffer size has considerable impact
on the QoS performance of EDCA under Poisson traffic. To investigate the
performance of EDCA in wireless multimedia networks, an analytical model is
further developed for EDCA under heterogeneous traffic. The performance results
demonstrate the significant effects of heterogeneous traffic on the total delay and
frame losses of EDCA with different buffer sizes. Finally, an efficient admission
control scheme is presented for the IEEE 802.11e WLANs based on analytical
modelling and a game-theoretical approach. The admission control scheme can
maintain the system operation at an optimal point where the utility of the Access
Point (AP) is maximized with the QoS constraints of various users
Recent Advances in Signal Processing
The signal processing task is a very critical issue in the majority of new technological inventions and challenges in a variety of applications in both science and engineering fields. Classical signal processing techniques have largely worked with mathematical models that are linear, local, stationary, and Gaussian. They have always favored closed-form tractability over real-world accuracy. These constraints were imposed by the lack of powerful computing tools. During the last few decades, signal processing theories, developments, and applications have matured rapidly and now include tools from many areas of mathematics, computer science, physics, and engineering. This book is targeted primarily toward both students and researchers who want to be exposed to a wide variety of signal processing techniques and algorithms. It includes 27 chapters that can be categorized into five different areas depending on the application at hand. These five categories are ordered to address image processing, speech processing, communication systems, time-series analysis, and educational packages respectively. The book has the advantage of providing a collection of applications that are completely independent and self-contained; thus, the interested reader can choose any chapter and skip to another without losing continuity
Satellite Networks: Architectures, Applications, and Technologies
Since global satellite networks are moving to the forefront in enhancing the national and global information infrastructures due to communication satellites' unique networking characteristics, a workshop was organized to assess the progress made to date and chart the future. This workshop provided the forum to assess the current state-of-the-art, identify key issues, and highlight the emerging trends in the next-generation architectures, data protocol development, communication interoperability, and applications. Presentations on overview, state-of-the-art in research, development, deployment and applications and future trends on satellite networks are assembled
Cross-layer analysis for video transmission over COFDM-based wireless local area networks
EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Location prediction and trajectory optimization in multi-UAV application missions
Unmanned aerial vehicles (a.k.a. drones) have a wide range of applications in e.g., aerial surveillance, mapping, imaging, monitoring, maritime operations, parcel delivery, and disaster response management. Their operations require reliable networking environments and location-based services in air-to-air links with cooperative drones, or air-to-ground links in concert with ground control stations. When equipped with high-resolution video cameras or sensors to gain environmental situation awareness through object detection/tracking, precise location predictions of individual or groups of drones at any instant possible is critical for continuous guidance. The location predictions then can be used in trajectory optimization for achieving efficient operations (i.e., through effective resource utilization in terms of energy or network bandwidth consumption) and safe operations (i.e., through avoidance of obstacles or sudden landing) within application missions. In this thesis, we explain a diverse set of techniques involved in drone location prediction, position and velocity estimation and trajectory optimization involving: (i) Kalman Filtering techniques, and (ii) Machine Learning models such as reinforcement learning and deep-reinforcement learning. These techniques facilitate the drones to follow intelligent paths and establish optimal trajectories while carrying out successful application missions under given resource and network constraints. We detail the techniques using two scenarios. The first scenario involves location prediction based intelligent packet transfer between drones in a disaster response scenario using the various Kalman Filtering techniques. The second scenario involves a learning-based trajectory optimization that uses various reinforcement learning models for maintaining high video resolution and effective network performance in a civil application scenario such as aerial monitoring of persons/objects. We conclude with a list of open challenges and future works for intelligent path planning of drones using location prediction and trajectory optimization techniques.Includes bibliographical references
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