Sökning: "MIMO"

Visar resultat 41 - 45 av 213 avhandlingar innehållade ordet MIMO.

  1. 41. Mobile Antenna Systems for 4G and 5G Applications with User Body Interaction

    Författare :Kun Zhao; Sailing He; Cyril Luxey; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Antenna; MIMO; mmWave; Mobile communication; SAR; Power density; User body effect; Channel modeling; Multiplex efficiency; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : In the thesis, the user body effect on antennas in a mobile terminal is discussed. In order to overcome the degradation of Multiple-Input Multiple-Output (MIMO) performance due to the user body effect, a quad-elements MIMO antenna array which can mitigate the body effect through an adaptive antenna switching method is introduced for 4G mobile terminals. LÄS MER

  3. 42. Aperiodic Array Synthesis for Telecommunications

    Författare :Carlo Bencivenni; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; PtP; mutual coupling; SATCOM; compressive sensing; aperiodic array; density taper; MU-MIMO; maximally sparse array; LoS-MIMO;

    Sammanfattning : Arrays of antennas offer important advantages over single-element antennas and are thus a key part of most advanced communication systems. The majority of current arrays are based on a classical regular layout, which offer simple design criteria despite some limitations. LÄS MER

  4. 43. Adaptation in multiple input multiple output systems with channel state information at transmitter

    Författare :Jinliang Huang; Svante Signell; Anders Ahlén; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; MIMO; adaptive modulation; power allocation; spectral efficiency; CSI; Electrical engineering; Elektroteknik;

    Sammanfattning : This thesis comprises two parts: the first part presents channel-adaptive techniques to achieve high spectral efficiency in a single user multiple-input multiple-output (MIMO) system; the second part exhibits a programmable and reconfigurable software-defined-radio orkbench(SDR-WB) in the Matlab/Octave environment that accommodates a variety of wireless applications. In an attempt to achieve high spectral efficiency, an adaptive modulation technique is applied at the transmitter to vary the data rate depending on the channel state information (CSI). LÄS MER

  5. 44. Multiple Antenna Terminals in Realistic Environments - A Composite Channel Modeling Approach

    Författare :Fredrik Harrysson; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Channel model; MIMO; multiple antennas terminal; propagation; user interaction; vehicular channel; diversity; spatial multiplexing; channel measurement;

    Sammanfattning : For evaluation of specific antenna arrangements in wireless communication systems we need physical channel models that take into account also the directional domain of the propagation channel. In this thesis we investigate, validate and propose a practical approach to wireless channel modeling and, particularly, to mobile communication systems. LÄS MER

  7. 45. Modeling Approaches for Active Antenna Transmitters

    Författare :Parastoo Taghikhani; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; thermal model.; MIMO; power amplifier; Active antenna transmitter; hybrid beamforming; electrothermal; active subarray antenna; nonlinear distortion;

    Sammanfattning : The rapid growth of data traffic in mobile communications has attracted interest to Multiple-Input-Multiple-Output (MIMO) communication systems at millimeter-wave (mmWave) frequencies. MIMO systems exploit active antenna arrays transmitter configurations to obtain higher energy efficiency and beamforming flexibility. LÄS MER