Sökning: "DS-CDMA"

Visar resultat 1 - 5 av 25 avhandlingar innehållade ordet DS-CDMA.

  1. 1. Successive Interference Cancellation in DS-CDMA Systems

    Författare :Ann-Louise Johansson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; group-wise detection; direct-sequence code division multiple access DS-CDMA ; multiuser detection; multirate schemes; weighted cancellation; successive interference cancellation;

    Sammanfattning : There is every indication that direct-sequence code division multiple access (DS-CDMA) will be one of the multiple access schemes for the third generation wireless mobile systems. CDMA is a flexible multiple access method suitable for supporting many new services (speech, data, video, etc), which are becoming increasingly important for mobile communications. LÄS MER

  3. 2. Multirate Schemes and Multiuser Decoding in DS/CDMA Systems

    Författare :Tony Ottosson Gadd; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; multi processing-gain; multi-channel; soft decoding; vector quantization.; joint optimization; Direct-Sequence Code Division Multiple-Access DS CDMA . multirate; multi-modulation; multiuser detection;

    Sammanfattning : Direct-Sequence Code Division Multiple-Access (DS/CDMA) has for some yearsbeen considered as a candidate for future personal and mobile communications.The reasons are mainly the properties of universal frequency reuse andthe multi-path mitigation. LÄS MER

  4. 3. Interference Cancellation for DS/CDMA Systems in Flat Fading Channels

    Författare :Ann-Louise Johansson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; mixed modulation; direct-sequence code division multiple access DS CDMA ; multiuser detection.; multiple data rates; parallel channels; multicode; interference cancellation;

    Sammanfattning : This thesis investigates interference cancellation in direct-sequence codedivision multiple access (DS/CDMA) systems that support multiple data rates.Two approaches for implementing multiple data rates are considered. Oneis the use of mixed modulation. The second is the use of parallel channels. LÄS MER

  5. 4. Coding, Modulation and Multiuser Decoding for DS-CDMA Systems

    Författare :Tony Ottosson Gadd; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : The general trend both in wireless and fixed network communication systems is flexibility in services, data rates, desired delay and performance. Future systems should not be designed for specific services but be more general and allow for a multitude of services, both now existing and those not yet invented. LÄS MER

  7. 5. 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