Avancerad sökning

Visar resultat 1 - 5 av 40 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Detection principles for fast Rayleigh fading channels using an antenna array

   Författare :Anders Hansson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; iterative decoding; serially concatenated coding; adaptive antenna arrays; multiple antennas; APP algorithm; diversity reception; Rayleigh channels; correlation; sequence detection; fading channels;

   Sammanfattning : .... LÄS MER

3. 2. 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

4. 3. Short-Packet Communications: Fundamental Performance and Key Enablers

   Författare :Johan Östman; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Rayleigh fading; Block-fading channels; Rician fading; variable-length stop-feedback; short-packet channel codes.; ultra-reliable low-latency;

   Sammanfattning : The paradigm shift from 4G to 5G communications, predicted to enable new use cases such as ultra-reliable low-latency communications (URLLC), will enforce a radical change in the design of communication systems. Unlike in 4G systems, where the main objective is to have a large transmission rate, in URLLC, as implied by its name, the objective is to enable transmissions with low latency and, simultaneously, very high reliability. LÄS MER

5. 4. 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. 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