Sökning: "Reference signals"

Visar resultat 21 - 25 av 91 avhandlingar innehållade orden Reference signals.

  1. 21. Blind Massive MIMO Base Stations : Downlink Transmission and Jamming

    Författare :Marcus Karlsson; Erik G. Larsson; Emil Björnson; Ralf Müller; Linköpings universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : Massive MIMO (Multiple-Input--Multiple-Output) is a cellular-network technology in which the base station is equipped with a large number of antennas and aims to serve several different users simultaneously, on the same frequency resource through spatial multiplexing. This is made possible by employing efficient beamforming, based on channel estimates acquired from uplink reference signals, where the base station can transmit the signals in such a way that they add up constructively at the users and destructively elsewhere. LÄS MER

  3. 22. An electronic warfare perspective on time difference of arrival estimation subject to radio receiver imperfections

    Författare :Johan Falk; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Signal processing; Signalbehandling;

    Sammanfattning : In order to ensure secure communication in digital military radio systems, multiple methods are used to protect the transmission from being intercepted by enemy electronic warfare systems. An intercepted transmission can be used to estimate several parameters of the transmitted signal such as its origin (position or direction) and of course the transmitted message itself. LÄS MER

  4. 23. Augmenting L1 Adaptive Control of Piecewise Constant Type to Aerial Vehicles

    Författare :Anders Pettersson; Institutionen för reglerteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : In aerial vehicle control design, the industrial baseline is to use robust control methods together with gain-scheduling to cover the full airspeed and altitude flight envelope. An adaptive controller could possibly add value by increasing performance while keeping robustness to deviation from nominal assumptions. LÄS MER

  5. 24. Channel Estimation and Prediction for MIMO OFDM Systems : Key Design and Performance Aspects of Kalman-based Algorithms

    Författare :Daniel Aronsson; Mikael Sternad; Ove Edfors; Uppsala universitet; []
    Nyckelord :channel estimation; channel prediction; OFDM; Kalman filtering; Electrical Engineering with specialization in Signal Processing; Elektroteknik med inriktning mot signalbehandling;

    Sammanfattning : Wireless broadband systems based on Orthogonal Frequency Division Multiplexing (OFDM) are being introduced to meet demands for high data transfer rates. In multiple users systems, the available bandwidth has to be shared efficiently by several users. The radio channel quality will fluctuate, or fade, as users move. LÄS MER

  7. 25. The revolutionary partnership of computation and biology

    Författare :Salvador Daniel Rivas-Carrillo; Tanel Punga; Manfred Grabherr; Jan Komorowski; Mauno Vihinen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES;

    Sammanfattning : The organization of living beings is complex. Science uses modeling in order to gain a deeper understanding, and to be able to manipulate the processes of living organisms. To this purpose, I used and developed computational tools to investigate and model different relevant biological phenomena. LÄS MER