Sökning: "code-division multiple-access CDMA"

Visar resultat 16 - 20 av 32 avhandlingar innehållade orden code-division multiple-access CDMA.

1. 16. Coding, Decoding and Multiuser Detection for Wireless CommunicationsCoding, Decoding and Multiuser Detection for Wireless Communications

   Författare :Pål Orten; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; direct-sequence code division multiple access DS-CDMA ; sequential decoding; Rayleigh fading; multirate DS-CDMA; optimum distance spectrum; rate matching; rate compatible punctured convolutional codes; multiuser detection; nested codes;

   Sammanfattning : In the strive for making the Universal Mobile Telecommunication System(UMTS) a reality, concepts and techniques are to be developed which canprovide both high system capacity and sufficient quality for the increasingnumber of mobile users. To obtain these objectives, powerful and flexibleerror control coding is needed, as well as efficient means for many usersto share the same commmication medium. LÄS MER

3. 17. On interference suppression techniques for communication systems

   Författare :Hongxia Zhao; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CDMA; QPSK; fixed-point implementation; DQPSK; rapid single flux quantum RSFQ ; MUD; unequal BER; fiber-optic communications; unequal SER; ISI;

   Sammanfattning : The work presented in this thesis concerns interferencesuppression techniques in two different communication systems.In the first part we study fiber-optic systems with practical non-ideal transmitters and receivers, which give rise to intersymbol interference (ISI). LÄS MER

4. 18. On Soft Decoding and Robust Vector Quantization

   Författare :Mikael Skoglund; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; speech and image coding; intersymbol interference; Rayleigh fading; soft decoding; CDMA; index assignment; Hadamard transform; channel optimized VQ; robust VQ; combined source-channel coding; vector quantization VQ ; noisy channels;

   Sammanfattning : This thesis considers vector quantization for noisy channels. Vector quantization (VQ) is an important technique for block-based source coding, with applications in, e.g., speech and image coding. LÄS MER

5. 19. Error Correction Coding for Optical CDMA

   Författare :Henrik Lundqvist; KTH; []
   Nyckelord :;

   Sammanfattning : The optical fiber is a very attractive communication mediumsince it offers a large bandwidth and low attenuation and cantherefore facilitate demanding services such as high-qualityvideo transmission. As the reach of optical fiber is beingextended to the access network it is economically attractive toshare fibers between different users without adding activecomponents in the network. LÄS MER

7. 20. 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