Sökning: "spectrum"

Visar resultat 1 - 5 av 1668 avhandlingar innehållade ordet spectrum.

  1. 1. On Finding Spectrum Opportunities in Cognitive Radios : Spectrum Sensing and Geo-locations Database

    Författare :Mohamed Hamid; Ben Slimane; Niclas Björsell; Muhammad Imadua Rahman; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; COgnitive Radio; Dynamic Spectrum Access; Spectrum Opportunity; Spectrum Sensing; GEo-locations database;

    Sammanfattning : The spectacular growth in wireless services imposes scarcity in term of the available radio spectrum. A solution to overcome this scarcity is to adopt what so called cognitive radio based on dynamic spectrum access. LÄS MER

  2. 2. Implementing spectrum commons: Implications for Thailand

    Författare :Nattawut Ard-Paru; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; spectrum commons; institutional analysis and development IAD framework; spectrum assignment; spectrum allocation; Radio Regulations RR ; World Radiocommunication Conference WRC ; spectrum management;

    Sammanfattning : Spectrum is a natural and limited resource that needs to be managed both internationally and nationally because of the unique propagation characteristics of radio waves. Once transmitted, a radio signal propagates until its power is depleted. Furthermore, electromagnetic energy does not recognize borders between countries. LÄS MER

  3. 3. Spectrum Assignment Policy: Towards an Evaluation of Spectrum Commons in Thailand

    Författare :Nattawut Ard-Paru; Chalmers University of Technology; []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; collective use of spectrum; spectrum management; benefit and cost analysis; spectrum assignment; spectrum commons;

    Sammanfattning : There is consensus among economists, engineers, and lawyers that a traditional command-and-control approach to spectrum assignment is inefficient and that a market-based or commons approach can be more efficient. The purpose of this thesis is to find the benefits of using spectrum commons for frequency assignment in Thailand. LÄS MER

  4. 4. Topics in Dynamic Spectrum Access : Market Based Spectrum Sharing and Secondary User Access in Radar Bands

    Författare :Miurel Tercero Vargas; Jens Zander; Mikael Prytz; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; spectrum sharing; radar band; cognitive radio; Telecommunication; Telekommunikation; Systems engineering; Systemteknik;

    Sammanfattning : The steady growth in demand for spectrum has increased research interest in dynamic spectrum access schemes. This thesis studies some challenges in dynamic spectrum access based on two strategies: open sharing and hierarchical access. LÄS MER

  5. 5. Heterogeneous Materials - Diffusion, Laplace spectrum and NMR

    Författare :Matias Nordin; Chalmers University of Technology; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; perturbation; nmr; diffusion; laplace operator; spectrum; heterogeneous materials;

    Sammanfattning : Relations to the effective diffusion constant and the relaxation rate of the time-dependent diffusion coefficient for porous systems are derived from the Laplace operator spectrum. The Padé approximation is then explained in terms of the Laplace operator spectrum. LÄS MER