Sökning: "average spectral efficiency"

Visar resultat 1 - 5 av 23 avhandlingar innehållade orden average spectral efficiency.

  1. 1. Efficiency Enhancement Techniques for Free-Electron Lasers

    Författare :Alan Mak; Lunds universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; free-electron laser; accelerator physics; efficiency enhancement; undulator tapering; phase jump method; synchrotron radiation; Fysicumarkivet:2017:Mak;

    Sammanfattning : The central question addressed in this thesis is how to make the free-electron laser (FEL) more efficient. In recent years, coherent diffraction imaging provides an important motivation for efficiency enhancement. This is because a more efficient FEL process enables converting a larger fraction of the electron beam's power into optical power. LÄS MER

  3. 2. Adaptive MIMO Systems with Channel State Information at Transmitter

    Författare :Jinliang Huang; Svante Signell; Øien Geir; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; adaptive modulation; adaptive power allocation; average spectral efficiency; MIMO; BER.; Telecommunication; Telekommunikation;

    Sammanfattning :  This dissertation presents adaptation techniques that can achieve high spectral efficiency for single user multiple-input multiple-output (MIMO) systems. Two types of adaptation techniques, adaptive modulation and adaptive powe allocation, are employed to adapt the rate and the transmit power to fading channels. LÄS MER

  4. 3. Cross-Layer Energy-Efficient Mobile Network Design

    Författare :Peiliang Chang; Guowang Miao; Jens Zander; Eduard Jorswieck; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; green mobile networks; energy efficiency; base station sleeping; resource allocation; mobile edge computing; interference coordination; NOMA; gröna mobilnätverk; energieffektivitet; basstationssömn; resursallokering; mobil kantnodsberäkning; störningssamordning; Informations- och kommunikationsteknik; Information and Communication Technology;

    Sammanfattning : To assure the sustainable development of mobile networks, it is crucial to improve their energy efficiency. This thesis is devoted to the design of energy-efficient mobile networks. A cross-layer design approach is adopted. LÄS MER

  5. 4. High-End Performance with Low-End Hardware : Analysis of Massive MIMO Base Station Transceivers

    Författare :Christopher Mollén; Erik G. Larsson; A. Lee Swindlehurst; Linköpings universitet; []
    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; NATURVETENSKAP; NATURAL SCIENCES; Beamforming; distortion; massive MIMO; MIMO; nonlinear hardware; peak-to-average ratio;

    Sammanfattning : Massive MIMO (multiple-input–multiple-output) is a multi-antenna technology for cellular wireless communication, where the base station uses a large number of individually controllable antennas to multiplex users spatially.  This technology can provide a high spectral efficiency. LÄS MER

  7. 5. Evaluation and Compensation of Nonlinear Distortion in Multicarrier Communication Systems

    Författare :Ali Behravan; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nonlinearity; Multicarrier communication systems; peak-to-average power ratio;

    Sammanfattning : In modern wireless communication systems with increasing data transfer rateand mobility, designing efficient transceivers is a key issue. Among differentchallenges, nonlinearity of high power amplifiers is a problem that has to beovercome by means of adding extra hardware or using more efficient signalprocessing algorithms. LÄS MER