Sökning: "Rayleigh fading"

Visar resultat 6 - 10 av 57 avhandlingar innehållade orden Rayleigh fading.

  1. 6. Prediction of Mobile Radio Channels : Modeling and Design

    Författare :Torbjörn Ekman; Rodney Vaughan; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Systemteknik; mobile radio channel; fading; channel model; channel estimation; channel prediction; power prediction; Systemteknik; Systems engineering; Systemteknik; Signal Processing; signalbehandling;

    Sammanfattning : Prediction of the rapidly fading envelope of a mobile radio channel enables a number of capacity improving techniques like fast resource allocation and fast link adaptation. This thesis deals with linear prediction of the complex impulse response of a channel and unbiased quadratic prediction of the power. LÄS MER

  3. 7. Convolutional Codes for Wireless Packet Data Systems

    Författare :Sorour Falahati; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; tailbiting coding; rate compatible punctured convolutional codes; adaptive modulation system; hybrid type-II ARQ; Rayleigh fading.;

    Sammanfattning : Automatic Repeat reQuest (ARQ) schemes can guarantee an almost error freereception strongly required in data communications. Hybrid type-II ARQschemes are supplied with channel coding to further improve the performance.In these schemes, error correction is performed adaptively which makesthem favorable for applications in time varying channels. LÄS MER

  4. 8. Energy Constrained Wireless Sensor Networks : Communication Principles and Sensing Aspects

    Författare :Erik Björnemo; Anders Ahlén; Mikael Sternad; Erik Larsson; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wireless sensor network; communication under processing cost; wireless channels; fading; probability theory as logic; uncertainty; measurement capacity; Signal processing; Signalbehandling;

    Sammanfattning : Wireless sensor networks are attractive largely because they need no wired infrastructure. But precisely this feature makes them energy constrained, and the consequences of this hard energy constraint are the overall topic of this thesis. LÄS MER

  5. 9. Channel Related Optimization of Wireless Communication Systems

    Författare :Fredrik Tufvesson; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; time division duplex; multicarrier; Radio communication; orthogonal frequency division multiplex; channel estimation; pilot symbol assisted modulation; sub-channel spacing; sub-channel bandwidth; interchannel interference; cyclic prefix; intersymbol interference; Rayleigh fading; precoding; pre-compensation;

    Sammanfattning : This thesis deals with different optimization problems in the design of wireless communication systems. It is mainly directed to the design of systems based on multicarrier techniques and orthogonal frequency division multiplex, OFDM, but some of the problems apply to single carrier systems as well. LÄS MER

  7. 10. Multirate Codes and Multicarrier Modulation for Future Communication Systems

    Författare :Pål Frenger; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; channel estimation; code-spread CDMA; DS-CDMA; convolutional codes; interference cancellation; nested convolutional codes; multicarrier modulation; optimum distance spectrum ODS ; rate-compatible punctured convolutional codes RCPC-codes ; OFDM; turbo decoding; rate matching; parallel combinatory signaling; Rayleigh fading;

    Sammanfattning : In this thesis, new detection and modulation methods for multicarrier systems are presented. The proposed multicarrier detectors are based on feedback of previously detected symbols and the idea is to exploit the correlation, both in time between consecutive symbols, and in frequency between neighboring sub-carriers. LÄS MER