Recent years have seen dramatic growth in Internet usage and an increasing convergence between Internet and wireless communications. There has also been renewed interest in iteratively decoded low-density parity-check (LDPC) codes due to their capacity approaching performance on AWGN channels.

Thesis (M.S.)--Pennsylvania State University, 2008. / Mode of access: World Wide Web.

Σχεδόν όλα τα σύγχρονα τηλεπικοινωνιακά συστήματα, τα οποία προορίζονται για μεταφορά ή αποθήκευση δεδομένων, έχουν υιοθετήσει κώδικες διόρθωσης λαθών για την αύξηση της αξιοπιστίας και τη μείωση της απαιτούμενης ισχύος εκπομπής. Μία αρκετά συχνά χρησιμοποιούμενη επιλογή είναι οι κώδικες Reed Solomon που έχουν την υψηλότερη δυνατή ελάχιστη απόσταση μεταξύ των κωδικών λέξεων για δεδομένη διορθωτική ικανότητα. Στην εργασία αυτή μελετήθηκαν οι ιδιότητες των κωδίκων αυτών, έγινε ανάλυση των διαφόρων αλγορίθμων αποκωδικοποίησης και ο σχεδιασμός σε FPGA των λειτουργιών κωδικοποίησης και αποκωδικοποίησης. Πιο συγκεκριμένα, έγινε εκτενής χρήση του συνθέσιμου μικρελεγκτή της Xilinx, του Picoblaze για τα δύο συστήματα που αφορούν τον κώδικα RS (255,239), υιοθετώντας μια παράλληλη αρχιτεκτονική για τον αποκωδικοποιητή, έχοντας ως στόχο μια οικονομική ως προς τους χρησιμοποιούμενους πόρους υλοποίηση. Η αρχιτεκτονική αυτή τροποποιήθηκε με σκοπό την επίτευξη υψηλότερης ταχύτητας λειτουργίας, αυξάνοντας το χρησιμοποιούμενο hardware. Ο σχεδιασμός υλοποιήθηκε σε ένα Virtex4 της Xilinx, χρησιμοποιώντας εργαλεία της Xilinx και διαπιστώθηκε η ορθή του λειτουργία χρησιμοποιώντας αντίστοιχα bit-accurate μοντέλα που αναπτύχθηκαν σε Matlab. / -

Thesis (Ph. D.)--University of Hawaii at Manoa, 2001. / Includes bibliographical references (leaves 145-150). Also available on microfiche.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / In order to reduce the ground segment equipment cost for small space missions, the French national space center (CNES) had the need to develop a CCSDS down-link interface board for low telemetry rates (< 1.5 Mb/s). This board performs frame synchronization and Reed-Solomon decoding. An important part of this design was the Reed-Solomon decoder development. In order to maintain low recurrent cost for this board, this decoder was realized in FPGA technology. Reed-Solomon decoding function, interleaving function (from 1 to 5) and virtual fill management are included in the same component. All set-up parameters are software programmable via the PCI bus, data and status are also available via the PCI bus under windows NT operating system. This paper presents the main features of this board and an overview of the Reed-Solomon decoder development.

Med den stora utvecklingen inom teknologi ämnad för förfalskning av dokument och filer ökarbehovet av att kunna verifiera äktheten och integriteten hos digitala filer. Företaget "TheUndisputable Truth" har introducerat en metod för att lösa detta problem genom att användahashkoder i en blockchain. Istället för att spara hela dokument online, sparas en pseudounikhashkod av filen. Hashkoden är en kryptografiskt genererad representation av filen sompraktiskt taget endast kan skapas från originalfilen och är extremt svår att återskapa utan att hatillgång till filen. En minimal ändring i filen genererar en helt annan hashkod, vilket gör detomöjligt att avgöra filernas likhet utifrån hashkoderna.Projektet syftade till att utveckla en metod som bevarar säkerheten hos hashkoderna samtidigtsom den kan detektera och redovisa små avvikelser i innehåll mellan en fil och en krypteradversion av en fil med mycket liknande innehåll i systemet, med frågeställningen huruvida det varpraktiskt och möjligt. För att uppnå detta undersöktes användningen av felkorrigeringstekniker,specifikt Hammingkoder och Reed Solomon.Initialt undersöktes applikationer av felkorrigering på texter. Hammingkoder är till sin naturbegränsade till att detektera och lokalisera ett fel, men visade att felkorrigering var applicerbart.Reed Solomon kunde hantera ett fel per två extrapunkter av information. Dock uppstod problemom en felaktighet försköt texten, vilket resulterade i att allt efter felet betraktades som felaktigt,då Reed Solomon-algoritmen är designad för meddelanden av bestämd längd. För att lösadetta delades texten upp i segment som avgränsades av ett nyckeltecken och ordnades efterbitarnas innehåll, vilket resulterade i att förskjutningsfel begränsades till små segment av texten.Detta bedömdes att tillfredsställa kraven på algoritmen.När det gäller bilder undersöktes möjligheten att hantera beskurna bilder med hjälp av en metodsom inom projektet kallades Reed Solomon snapping. Metoden grundades i att sparasegmenterade bitar och testa en något större bit än de sparade bitarna, för att sedan användaReed Solomon för att fastställa positionen för beskärningen om den fanns med. Dock leddedenna metod till enorm datalagring och betydande tidsåtgång, vilket gjorde det orealistiskt attuppnå projektets mål med den befintliga teknologin. Möjligtvis är det applicerbart på andraområden, till exempel identifiering av huruvida ett kapitel ingår i en bok.Frågeställningen bedömdes besvaras jakande för texter, då algoritmen klarade målet förprojektet. Däremot kunde detta inte sägas för bilder, som kräver vidare forskning.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Range Safety Systems are used for destruction of a vehicle should a malfunction cause the vehicle to veer off course. All vehicles launched into space require implementation of a Range Safety System. For years the IRIG receivers have been used with relatively good success. Unfortunately, the IRIG receivers do not provide a high level of security. High alphabet receivers were later developed for use on the big launchers (Atlas, Delta, Titan, etc) and the manned missions (Shuttle) to provide added security. With the IRIG based system, several problems have occurred resulting in the loss millions of dollars worth of equipment. Due to the problems that have occurred it has become apparent that there is a need for a more secure, low cost, type of range safety receiver. This paper describes the design and development of the prototype EFTS system. Mission critical parameters are discussed including selection of the encryption and forward error correction algorithms. Actual measured performance including message error rate characteristic is presented.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / This paper describes a method for evaluating error correction techniques for applicability to the flight testing of aircraft. No statistical or math assumptions about the channel or sources of error are used. An empirical method is shown which allows direct “with and without” comparative evaluation of correction techniques. A method was developed to extract error sequences from actual test data independent of the source of the dropouts. Hardware was built to allow a stored error sequence to be repetitively applied to test data. Results are shown for error sequences extracted from a variety of actual test data. The effectiveness of Reed-Solomon (R-S) encoding and interleaving is shown. Test bed hardware configuration is described. Criteria are suggested for worthwhile correction techniques and suggestions are made for future investigation.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper describes the PTP EX, a 160 Mbps Telemetry and Command front-end system, which takes advantage of the state-of-the-art in networking and software technology, and the rapid development in PC components and FPGA design. Applications for the PTP EX include High-rate Remote Sensing Ground Stations, Satellite/Payload Integration and Testing, High-rate Bit Error Rate Test (BERT) System and High-rate Digital Recorder/Playback System. The PTP EX Interface Board, the MONARCH-EX PCI High Speed Frame Synchronizer/Telemetry Simulator with Reed-Solomon Encoder/Decoder, is designed with the following key capabilities: · 160 Mbps serial input for CCSDS Frame Processing (Frame Synchronization, Derandomization, CRC, Reed-Solomon decoding, time stamping, quality annotation, filtering, routing, and stripping); · 160 Mbps disk logging of Reed-Solomon corrected CCSDS frames with simultaneous real-time processing of spacecraft engineering data and ancillary payload data; · Onboard CCSDS Telemetry Simulation with 160 Mbps serial output (Sync Pattern, background pattern, ID counter, time stamp, CRC, Reed-Solomon encoding, Randomization, and Convolutional encoding); · Bit Error Rate Testing up to 160 Mbps (Pseudo-random transmitter and receiver with bit error counter). The innovative architecture of the MONARCH-EX allows for simultaneous logging of a high-rate data stream and real-time telemetry processing. The MONARCH-EX is also designed with the latest in field-programmable gate array (FPGA) technology. FPGAs allow the board to be reprogrammed quickly and easily to perform different functions. Thus, the same hardware can be used for both Telemetry processing and simulation, and BERT applications. The PTP EX also takes advantage of the latest advances in off-the-shelf PC computing and technology, including Windows NT, Pentium II, PCI, Gigabit Ethernet, and RAID subsystems. Avtec Systems, Inc. is leveraging the PTP EX to take advantage of the continuous improvement in high-end PC server components.

ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NV / The performance of telemetry systems may be strongly affected by diverse sources of perturbations. Among them, multipath channels and transmission noise are the most critical. While the effects due to the multipath channels can be attenuated thanks to equalization, the effects of the noise are limited if forward error correction is used. This paper first proves that the combination of blind equalization and forward error correction can strongly improve bit error rates. The other objective of the paper is to show that reasonably powerful codes like Reed-Solomon codes are sufficient to enable quasi-error free transmissions in a large majority of propagation channel scenarios.