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Visar resultat 1 - 5 av 18 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. On Reconfigurable MEMS Antennas and Coupling Matrix Estimation

    Författare :Marc Mowlér; Björn Lindmark; Björn Ottersten; Pertti Vainikainen; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Telekommunications; Antennas; Estimation Theory; Telecommunication; Telekommunikation;

    Sammanfattning : In this thesis, two different topics are treated related to wireless communication. Part I presents three different reconfigurable MEMS integrated antennas for MIMO applications. Simulation and measurement results are presented along with brief discussions on the topic of antenna selection with reconfigurable antenna elements. LÄS MER

  3. 2. Multiantenna Cellular Communications : Channel Estimation, Feedback, and Resource Allocation

    Författare :Emil Björnson; Björn Ottersten; Mats Bengtsson; Marios Kountouris; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; channel estimation; limited feedback; multicell communications; resource allocation;

    Sammanfattning : The use of multiple antennas at base stations and user devices is a key component in the design of cellular communication systems that can meet the capacity demands of tomorrow. The downlink transmission from base stations to users is particularly limiting, both from a theoretical and a practical perspective, since user devices should be simple and power-efficient, and because many applications primarily create downlink traffic (e. LÄS MER

  4. 3. Transmission Optimization for High Throughput Satellite Systems

    Författare :Ahmad Gharanjik; Mats Bengtsson; Björn OTTERSTEN; Wing-Kin (Ken) Ma; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Demands on broadband data service are increasing dramatically each year. Following terrestrial trends, satellite communication systems have moved from the traditional TV broadcasting to provide interactive broadband services even to urban users. LÄS MER

  5. 4. Interference Mitigation and Synchronization for Satellite Communications

    Författare :Joel Grotz; Björn Ottersten; Dirk Slock; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Signal processing; Signalbehandling;

    Sammanfattning :  Within this thesis, the satellite broadcast scenario of geostationary satellites is reviewed. The densely crowded geostationary arc in the common broadcast frequencies may create significant interference from adjacent satellites (ASI). LÄS MER

  7. 5. Resource Allocation in Multi-Antenna Communication Systems with Limited Feedback

    Författare :David Hammarwall; Björn Ottersten; David Gesbert; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Telecommunication; Telekommunikation;

    Sammanfattning : The use of multiple transmit antennas is considered a key ingredient to significantly improve the spectral efficiency of wireless communication systems beyond that of currently employed systems. Transmit beamforming schemes have been proposed to exploit the spatial characteristics of multi-antenna radio channels; that is, multiple-input single-output (MISO) channels. LÄS MER