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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Voice-over-IP (VoIP) over wireless local area networks (WLAN).

January 2004 (has links)
Wang Wei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 80-83). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivations and Contributions --- p.1 / Chapter 1.2 --- Organization of the Thesis --- p.4 / Chapter Chapter 2 --- Background --- p.6 / Chapter 2.1 --- IEEE 802.11 --- p.6 / Chapter 2.1.1 --- Distributed Coordination Function (DCF) / Point Coordination Function (PCF) --- p.7 / Chapter 2.1.2 --- Types of Networks --- p.8 / Chapter 2.1.3 --- The 802.11 MAC Sublayer Protocol --- p.9 / Chapter 2.1.4 --- Why CSMA/CA for Wireless LAN? --- p.11 / Chapter 2.2 --- Voice over IP (VoIP) --- p.13 / Chapter 2.2.1 --- Speech Codec --- p.13 / Chapter 2.2.2 --- The H.323 Standard --- p.13 / Chapter 2.3 --- Related Work --- p.15 / Chapter 2.3.1 --- Capacity limits of VoIP over WLAN --- p.16 / Chapter 2.3.2 --- Methods for increasing VoIP capacity over WLAN --- p.16 / Chapter 2.3.3 --- Interference between traffic of VoIP and other applications --- p.18 / Chapter Chapter 3 --- VoIP Multiplex-Multicast Scheme --- p.20 / Chapter 3.1 --- System Architecture --- p.20 / Chapter 3.2 --- Packet Multiplexing and Multicasting --- p.22 / Chapter 3.3 --- Header Compression --- p.24 / Chapter 3.4 --- Connection Establishment --- p.29 / Chapter Chapter 4 --- Capacity Analysis --- p.31 / Chapter 4.1 --- VoIP Capacity Analysis for 802. 11b --- p.31 / Chapter 4.1.1 --- Capacity of Ordinary VoIP over WLAN --- p.32 / Chapter 4.1.2 --- Capacity of Multiplex-Multicast Scheme over WLAN --- p.33 / Chapter 4.2 --- "VoIP Capacity Analysis for 802,11a and 802.11g" --- p.34 / Chapter 4.3 --- VoIP Capacity with VBR Sources --- p.38 / Chapter 4.4 --- Simulations --- p.38 / Chapter Chapter 5 --- Delay Performance --- p.41 / Chapter 5.1 --- Access Delay --- p.42 / Chapter 5.2 --- Extra Delay Incurred by the Multiplex-Multicast Scheme --- p.47 / Chapter Chapter 6 --- VoIP Co-existing with TCP Interference Traffic --- p.49 / Chapter 6.1 --- Ordinary VoIP co-existing with TCP over WLAN --- p.49 / Chapter 6.1.1 --- Problem Caused by TCP Interference --- p.49 / Chapter 6.1.2 --- Solutions --- p.52 / Chapter 6.2 --- M-M VoIP coexisting with TCP over WLAN --- p.53 / Chapter 6.3 --- 802.11e --- p.56 / Chapter 6.3.1 --- EDCA --- p.56 / Chapter 6.3.2 --- ACK Policies --- p.58 / Chapter 6.3.3 --- VoIP over EDCA --- p.58 / Chapter Chapter 7 --- Experimental Validation --- p.61 / Chapter 7.1 --- Transmission Errors --- p.61 / Chapter 7.2 --- Prototype Implementation --- p.62 / Chapter Chapter 8 --- VoIP over Ad Hoc Networks --- p.65 / Chapter 8.1 --- Mobile Ad Hoc Networks (MANET) and Wireless Distributed System (WDS) --- p.65 / Chapter 8.2 --- The M-M Scheme in WDS --- p.67 / Chapter 8.2.1 --- Modified System Architecture --- p.67 / Chapter 8.2.2 --- Delay Performance --- p.68 / Chapter 8.2.3 --- Analysis of M-M Scheme in WDS --- p.69 / Chapter 8.2.4 --- Capacity Improvement --- p.70 / Chapter 8.2.5 --- Delay Improvement --- p.71 / Chapter 8.2.6 --- Spectrum Reuse --- p.71 / Chapter Chapter 9 --- Conclusions --- p.76 / References --- p.80
12

Voice over IP performance using expedited forwarding and assured forwarding on differentiated services enabled network /

Lo, Chor Wing. January 2002 (has links)
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002. / Includes bibliographical references (leaves 57-59). Also available in electronic version. Access restricted to campus users.
13

The use and meaning of mobile phones in student lives

Standen, Natasha January 2003 (has links)
This thesis demonstrates the popularity of mobile telephony within a population of undergraduate students, and provides explanations regarding the adoption, use and meaning of mobile phones therein. Research has been conducted at the University of Newcastle upon Tyne amongst 1030 18-24 year old, full-time, UK-resident 'traditional entry' students, using social science methods. Due to a lack of existing research on this type of population, the thesis also includes ethnographic data from the everyday lives of the individuals concerned. This data in turn supports the main findings of the research. Although some theorists conceptualise the mobile phone as `impacting' on social life, this research adopts a `social shaping' approach from work in social studies of technology, and is also informed by social anthropology. This theoretical basis helps formulate the argument that changes engendered by the mobile phone must be viewed in association with other recent changes within the University and its population. Correspondingly, the thesis suggests that the mobile phone is now integral to what Haselgrove (1994) terms the 'student experience', precisely because of the nature of this experience for the contemporary undergraduate population. The thesis therefore provides an explanation of the adoption rates, use patterns and meanings associated with mobile phones within the undergraduate population at the University of Newcastle upon Tyne, in conjunction with a study of their behaviours and attitudes. It concludes that the use and meaning of mobile phones in student lives is directly linked to the specific circumstances of the population studied.
14

An audio architecture integrating sound and live voice for virtual environments /

Krebs, Eric M. January 2002 (has links) (PDF)
Thesis (M.S. in Modeling, Virtual Environments and Simulation)--Naval Postgraduate School, September 2002. / Thesis advisor(s): Russell D. Shilling, Rudolph P. Darken. Includes bibliographical references (p. 175). Also available online.
15

Securing media streams in an Asterisk-based environment and evaluating the resulting performance cost /

Clayton, Bradley. January 2007 (has links)
Thesis (M.Sc. (Computer Science)) - Rhodes University, 2007.
16

Internet Telephony and Open Communications Policy

McKnight, Lee January 1998 (has links)
No description available.
17

Internet Telephony: Costs, Pricing, and Policy

McKnight, Lee, Leida, Brett January 1998 (has links)
No description available.
18

Complementary Products and Modular Innovation in Internet Telephony

Gawer, Annabelle January 1997 (has links)
Presentation at ITC semiannual meeting, Hewlett-Packard Laboratories, Bristol, UK, June 12-13, 1997
19

Security of VoIP : analysis, testing and mitigation of SIP-based DDoS attacks on VoIP networks : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Computer Science in the University of Canterbury /

Deng, Xianglin. January 2008 (has links)
Thesis (M. Sc.)--University of Canterbury, 2008. / Typescript (photocopy). Includes bibliographical references (leaves 103-110). Also available via the World Wide Web.
20

The Strategic Migration of Telephony into an Internet Protocol World : a South African Perspective

Adams, Pieter 25 April 2005 (has links)
Internet Protocol Telephony (IPT), also known as Voice over Internet Protocol (VoIP), has evolved from a niche technology to one that is adopted fairly well in developed countries. The aim of this research report was to determine whether IPT will also be a success in the Republic of South Africa, which is one of many developing countries. The technology was analysed and it was found that cost reduction, increased productivity and enhanced applications were the most valuable benefits the technology could offer. Particular interesting impediments of the technology were discovered and it was found that there existed both hard issues like security and quality problems, as well as softer issues like internal politics, that could hinder the global success of the technology. The adoption rate of South Africa was compared to that of industrial countries and it was found that South African organisations overall posed a wait-and-see attitude towards IPT. Various implementation models were discussed and it was found that a hybrid approach would be the most viable option for local organisations. The South African environment were analysed and it was discovered that the biggest obstacle for success in South Africa was the regulatory environment. But it was also found that the environment would soon change and that competitors, including Black Economic Empowerment companies, should use the opportunities available. Social factors like HIV/AIDS and theft as well as economic factors like the exchange rate could hamper the competitiveness of local companies using IPT. IPT technology can only be a success in South Africa if it is intensely supported by Government, implemented in the correct manner and adopted aggressively by the local market. / Dissertation (MBA)--University of Pretoria, 2006. / Graduate School of Management / unrestricted

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