| 1. |
- Andersson, Karl, et al.
(författare)
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Enhanced mobility support for roaming users : extending the IEEE 802.21 information service
- 2010
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Ingår i: Wired/Wireless Internet Communications. - Berlin : Encyclopedia of Global Archaeology/Springer Verlag. - 9783642133145 ; , s. 52-63
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Konferensbidrag (refereegranskat)abstract
- Many cell-phones and Personal Digital Assistants (PDAs) are equipped with multiple radio interfaces. Because of this, devices need to have ways of efficiently selecting the most suitable access network across multiple technologies based on the physical location of the device as well as user-defined parameters such as cost, bandwidth, and battery consumption. The IEEE has standardized the 802.21 framework for media-independent handovers where dynamic selection of network interfaces is an important feature. This paper describes and evaluates a novel architecture which extends the IEEE 802.21 information service. The architecture is based on a three-layer structure with Location-to-Service Translation (LoST) servers, service provider servers and independent evaluator servers. Evaluator servers are populated with information on coverage and quality of service as provided by trusted users. The proposed architecture allows for competition at all levels and scales well due to its distributed nature. A prototype has been developed and is presented in the paper.
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| 2. |
- Bajpai, Vaibhav, et al.
(författare)
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The Dagstuhl Beginners Guide to Reproducibility for Experimental Networking Research
- 2019
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Ingår i: Computer communication review. - New York : Association for Computing Machinery (ACM). - 0146-4833 .- 1943-5819. ; 49:1, s. 24-30
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Reproducibility is one of the key characteristics of good science, but hard to achieve for experimental disciplines like Internet measurements and networked systems. This guide provides advice to researchers, particularly those new to the field, on designing experiments so that their work is more likely to be reproducible and to serve as a foundation for follow-on work by others.
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| 3. |
- Marsh, Ian, 1965-
(författare)
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Quality aspects of internet telephony
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Internet telephony has had a tremendous impact on how people communicate.Many now maintain contact using some form of Internet telephony.Therefore the motivation for this work has been to address the quality aspectsof real-world Internet telephony for both fixed and wireless telecommunication.The focus has been on the quality aspects of voice communication,since poor quality leads often to user dissatisfaction. The scope of the workhas been broad in order to address the main factors within IP-based voicecommunication.The first four chapters of this dissertation constitute the backgroundmaterial. The first chapter outlines where Internet telephony is deployedtoday. It also motivates the topics and techniques used in this research.The second chapter provides the background on Internet telephony includingsignalling, speech coding and voice Internetworking. The third chapterfocuses solely on quality measures for packetised voice systems and finallythe fourth chapter is devoted to the history of voice research.The appendix of this dissertation constitutes the research contributions.It includes an examination of the access network, focusing on how calls are multiplexed in wired and wireless systems. Subsequently in the wireless case, we consider how to handover calls from 802.11 networks to the cellularinfrastructure. We then consider the Internet backbone where most of ourwork is devoted to measurements specifically for Internet telephony. The applications of these measurements have been estimating telephony arrival processes, measuring call quality, and quantifying the trend in Internet telephony quality over several years. We also consider the end systems, since they are responsible for reconstructing a voice stream given loss and delay constraints. Finally we estimate voice quality using the ITU proposal PESQ and the packet loss process.The main contribution of this work is a systematic examination of Internet telephony. We describe several methods to enable adaptable solutions for maintaining consistent voice quality. We have also found that relatively small technical changes can lead to substantial user quality improvements.A second contribution of this work is a suite of software tools designed to a certain voice quality in IP networks. Some of these tools are in use within commercial systems today.
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