Sökning: "Error correcting codes"

Visar resultat 21 - 25 av 32 avhandlingar innehållade orden Error correcting codes.

1. 21. On error-robust source coding with image coding applications

   Författare :Tomas Andersson; Mikael Skoglund; Astrid Lundmark; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; source coding; channel coding; joint source-channel coding; multiple description coding; image coding; vector quantization; channel optimized vector quantization; Telecommunication; Telekommunikation;

   Sammanfattning : This thesis treats the problem of source coding in situations where the encoded data is subject to errors. The typical scenario is a communication system, where source data such as speech or images should be transmitted from one point to another. A problem is that most communication systems introduce some sort of error in the transmission. LÄS MER

3. 22. Coding and Modulation for Wideband CDMA

   Författare :Ola Wintzell; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; turbo codes.; Electronics and Electrical technology; channel coding; impulse radio; coordinated transmission; pre-coding; cellular radio capacity; Direct sequence code division multiple access DS-CDMA ; pulse position hopped code division multiple access PPH-CDMA ; Elektronik och elektroteknik; Telecommunication engineering; Telekommunikationsteknik;

   Sammanfattning : Wideband CDMA (Code Division Multiple Access) is one of the key technologies for future mobile communication systems. This thesis studies various coding and transmission methods for wideband CDMA communications. In a cellular environment, the system performance depends on the interference from other cells. LÄS MER

4. 23. Signaling for Optical Intensity Channels

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

   Sammanfattning : With the growing popularity of social media services, e-commerce, and many other internet-based services, we are witnessing a rapid growth in the deployment of data centers and cloud computing platforms. As a result, the telecommunications industry has to continue providing additional network capacity to meet the increasing demand for bandwidth. LÄS MER

5. 24. 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

7. 25. Fingerprinting digital documents

   Författare :Tina Lindkvist; Thomas Johansson; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : In this thesis we look at the fingerprinting problem. Our belief is that it is very difficult to prevent illegal copying, so our solution is to mark each copy uniquely so that if it is spread illegally, the original owner of that copy can be found. The principle is the same as for a serial number on a product. LÄS MER