Sökning: "Voice over IP"

Visar resultat 1 - 5 av 18 avhandlingar innehållade orden Voice over IP.

  1. 1. IP telephony : Mobility and security

    Författare :Jon-Olov Vatn; Björn Pehrson; William Arbaugh; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Telekommunikation; Telekommunikation; Telecommunication; Telekommunikation;

    Sammanfattning : With the introduction of IP based telephony services, the Internet has started to challenge the traditional PSTN networks as an infrastructure for providing real-time interactive services. This upcoming paradigm shift is not only driven by the desire to provide cost efficient solutions, but by basing the communication on IP we expect that the end-users will experience a greater set of attractive services over a single connection compared to what is provided by a PSTN today. LÄS MER

  3. 2. Enabling Multimedia Services over Wireless Multi-Hop Networks

    Författare :Marcel Cavalcanti de Castro; Andreas Kassler; Torsten Braun; Karlstads universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Wireless Multi-hop Networks; Mobile Ad-hoc Networks; Wireless Mesh Networks; Voice over IP; Session Initiation Protocol; Peer-to-Peer Overlay Networks; Computer science; Datavetenskap; Datavetenskap; Computer Science;

    Sammanfattning : With the constant development of wireless technologies, the usageof wireless devices tends to increase even more in the future.Wireless multi-hop networks (WMNs) have emerged as a keytechnology to numerous potential scenarios, ranging from disasterrecovery to wireless broadband internet access. LÄS MER

  4. 3. Cross-Layer Optimization of Voice over IP in Wireless Mesh Networks

    Författare :Peter Dely; Andreas Kassler; Dirk Staehle; Karlstads universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Datavetenskap; Computer Science;

    Sammanfattning : Wireless Mesh Networks (WMNs) have emerged as a promising network technology, which combines the benefits of cellular networks and Wireless Local Area Networks (WLANs). In a WMN mesh routers wirelessly relay traffic on behalf of other mesh routers or clients and thereby provide coverage areas comparable to cellular networks, while having the low complexity and low costs of WLANs. LÄS MER

  5. 4. Coding Speech for Packet Networks

    Författare :Jonas Lindblom; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; packet loss concealment; voice over IP; speech coding; harmonic modeling; vector quantization; sinusoidal modeling; Gaussian mixture modeling; bounded support; frame erasure; variable dimension;

    Sammanfattning : The topic of this thesis is speech coding for packet networks. Problems related to the use of packet networks for voice communication are addressed. Real-time voice communication is for example very delay sensitive; if the total end-to-end delay in a telephone session grows large, it is perceived as annoying. LÄS MER

  7. 5. Robust Multimedia Communications over Packet Networks

    Författare :Guoqiang Zhang; W. Bastiaan Kleijn; Vinay Vaishampayan; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Telecommunication; Telekommunikation;

    Sammanfattning : Multimedia communications over packet networks, and in particular the voice over IP (VoIP) application, have become an integral part of society. However, the unreliable and heterogeneous nature of packet networks has led to a best-effort delivery of services. LÄS MER