Sökning: "quadrature amplitude modulation"

Visar resultat 6 - 10 av 26 avhandlingar innehållade orden quadrature amplitude modulation.

  1. 6. Fiber-Optic Systems with Coherent Detection and Four-Dimensional Modulation

    Författare :Martin E Sjödin; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; intradyne; polarization-switched QPSK; quadrature phase-shift keying QPSK ; coherent detection; self-homodyne; wavelength-division multiplexing; 16-ary quadrature amplitude modulation; self-phase modulation; 128-SP-QAM; polarization multiplexing; pilot tone;

    Sammanfattning : To increase the data rates of fiber-optic communication systems, modulation formats withhigher spectral efficiency and/or higher power efficiency than binary formats are of greatinterest. These formats require coherent detection and this thesis has been dedicated toinvestigating both novel modulation formats and two different types of coherent systems. LÄS MER

  3. 7. Phase Noise Tolerant Modulation Formats and DSP Algorithms for Coherent Optical Systems

    Författare :Jaime Rodrigo Navarro; Sergei Popov; Gunnar Jacobsen; Richard Schatz; Xiaodan Pang; Oskars Ozolins; Gabriella Bosco; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; optical communications; carrier phase recovery; blind phase search; circular quadrature amplitude modulation; CmQAM; coherent optical communications; digital signal processing; carrier phase estimation; equalization enhanced phase noise; EEPN; Telecommunication; Telekommunikation;

    Sammanfattning : Coherent detection together with multilevel modulation formats has the potential to significantly increase the capacity of existing optical communication systems at no extra cost in signal bandwidth. However, these modulation formats are more susceptible to the impact of different noise sources and distortions as the distance between its constellation points in the complex plane reduces with the modulation index. LÄS MER

  4. 8. Modulation Optimization for Noncoherent Optical Systems

    Författare :Johnny Karout; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Direct detection; noncoherent communications; lattice codes; mutual information; fiber-optical communications; intensity modula- tion; sphere packing.; infrared communications; free-space optical communications;

    Sammanfattning : There has been a significant improvement in high-speed electronics and optical components over the past few years, and this is one of the key enabling factors for high data rate transmission. Moreover, multi- level modulation formats, which encode information onto the carrier’s amplitude and phase, are necessary to increase the spectral efficiency of communication systems. LÄS MER

  5. 9. Voronoi Constellations for Coherent Fiber-Optic Communication Systems

    Författare :Shen Li; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; coded modulation; constellation shaping; geometric shaping; forward error correction coding; lattices; Voronoi constellations.; multidimensional modulation formats; Achievable information rates; coherent fiber-optic communications;

    Sammanfattning : The increasing demand for higher data rates is driving the adoption of high-spectral-efficiency (SE) transmission in communication systems. The well-known 1. LÄS MER

  7. 10. Frequency Noise in Coherent Optical Systems: Impact and Mitigation Methods

    Författare :Aditya Kakkar; Richard Schatz; Sergei Popov; Gunnar Jacobsen; Xiaodan Pang; Oskars Ozolins; Magnus Karlsson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Equalization enhanced phase noise; frequency noise; coherent optical communications; carrier phase recovery; carrier phase estimation; circular quadrature amplitude modulation; EEPN; CmQAM; blind phase search; phase noise;

    Sammanfattning : The increase in capacity demand along with the advancement in digital signal processing (DSP) have recently revived the interest in coherent optical communications and led to its commercialization. However, design and development of robust DSP algorithms for example for carrier phase recovery (CPR) becomes complex as we opt for high order modulation formats such as 16QAM and beyond. LÄS MER