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COMMUNICATIONS OVER AIRCRAFT POWER LINES: A PRACTICAL IMPLEMENTATIONTian, Hai, Trojak, Tom, Jones, Charles H. 10 1900 (has links)
ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / This paper presents a practical implementation of a hardware design for transmission of data over aircraft power lines. The intent of such hardware is to significantly reduce the wiring in the aircraft instrumentation system. The potential usages of this technology include pulse code modulation (PCM), Ethernet and other forms data communications. Details of the fieldprogrammable gate array (FPGA) and printed circuit board (PCB) designs of the digital and analog front end will be discussed. The power line is not designed for data transmission. It contains considerable noise, multipath effects, and time varying impedance. Spectral analysis data of an aircraft is presented to indicate the difficulty of the problem at hand. A robust modulation is required to overcome the harsh environment and to provide reliable transmission. Orthogonal frequency division multiplexing (OFDM) has been used in power line communication industry with a great deal of success. OFDM has been deemed the most appropriate technology for high-speed data transmission on aircraft power lines. Additionally, forward error correction (FEC) techniques are discussed.
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PERFORMANCE TRADE-OFFS WHEN IMPLEMENTING TURBO PRODUCT CODE FORWARD ERROR CORRECTION FOR AIRBORNE TELEMETRYTemple, Kip 10 1900 (has links)
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Hardware implementing forward error correction (FEC) is currently available for utilization by the
airborne telemetry system designer. This paper will discuss the potential benefits along with drawbacks
when using this technology. Laboratory testing is supplemented with real-world flight testing.
Performance results comparing FEC and non-FEC systems are presented for both IRIG-106 Pulse Code
Modulation/Frequency Modulation, PCM/FM, (or Continuous Phase Frequency Shift Keying, CPFSK,
with filtering, or ARTM Tier 0) and Shaped Offset Quadrature Phase Shift Keying, Telemetry Group
version (SOQPSK-TG or ARTM Tier I) waveforms.
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THE DESIGN OF A 21st CENTURY TELEMTRY SYSTEM WITH SOQPSK MODULATION AND INTEGRATED CONTROLWegener, John A., Roche, Michael C. 10 1900 (has links)
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / This paper describes a telemetry system developed for the EA-18G Flight Test program. The
program requires transmission of a number of data streams, in IRIG-106 Chapter 4 PCM, Chapter 8
Mux-All 1553, Ethernet, and Fibre Channel formats. The initial requested data rate was in excess of
30 Mbits/sec. The telemetry system must operate at a range up to about 120 miles, at several test
ranges, and with several different aircraft maneuvering configurations. To achieve these
requirements, the Flight Test Instrumentation group at Boeing Integrated Defense Systems in Saint
Louis, developed a telemetry system in conjunction with industry partners and test range customers.
The system transmits two telemetry streams with a total aggregate rate on the order of 20 Mbits/sec.
Each telemetry stream consists of up to four PCM streams, combined in a Teletronics Technology
Corporation (TTC) Miniature Adaptable Real-Time Multiplexer Unit (MARM) data combiner. It
uses Nova Engineering multi-mode transmitters capable of transmitting PCM-FM or Shaped Offset
Quadrature Phase Shift Keying (SOQPSK). The transmitter also provides Turbo-Product Code
(TPC) Forward Error Correction (FEC) to enhance range and improve link performance. Data
collection units purchased from outside vendors or developed by Saint Louis Flight Test
Instrumentation, translate Ethernet and Fibre Channel information into traditional PCM streams. A
Boeing Flight Test Instrumentation developed control system provides flexible selection of streams
to be combined into each telemetry stream, and functional control of antenna selection and
transmitter operation.
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BANDWIDTH EFFICIENCY AND BER PERFORMANCE OF ENHANCED AND FEC CODED FQPSKLin, Jinsong, Feher, Kamilo 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Bit error rate (BER) and bandwidth efficiency of several variations of enhanced Feher patented quadrature phase shift keying (FQPSK) [1] are described. An enhanced FQPSK increases the channel packing density of that of the IRIG 106-00 standardized FQPSK-B by approximately 50% in adjacent channel interference (ACI) environment. As the bandwidth efficiency of FQPSK-B DOUBLES (2×) that of pulse code modulation/Frequency modulation (PCM/FM) [5], the enhanced FQPSK, with a simpler transceiver than FQPSK-B, has a channel packing density of TRIPLE (3×) that of PCM/FM. One of the other enhanced FQPSK prototypes has an end to end system loss of only 0.4 dB at BER=1x10^(-3) and 0.5 dB at BER=1x10^(-4) from ideal linearly amplified QPSK theory. The enhanced FQPSK has a simple architecture, thus is inexpensive and has small size, for ultra high bit rate implementation. With low redundancy forward error correction (FEC) coding which expands the spectrum by approximately 10%, further improvement of about 3-4.5dB E N b o is attained with NLA FQPSK-B and enhanced FQPSK at BER=1x10^(-5) .
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Volumetric data throughput optimisation by dynamic FEC bearing frame length adaptationChristelis, Christian 03 1900 (has links)
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The telecommunications link between a LEO satellite and a rural ground station
with a non-tracking antenna, has a strongly varying link quality and
a short communications window. The satellite acts as a store-and-forward
node between ground stations. The TC-SDLP and an FTP protocol form a
shallow protocol stack, which excludes unneeded protocol functionality and
the resulting overhead. Coding gain, introduced by BCH FEC in the TCSDLP,
allows for link quality improvement.
The core of this thesis is an improvement of the TC-SDLP to maximise effective
payload data throughput, or goodput. This improvement was achieved
by creating an optimal segment length selection metric based on the BER.
Since the BER is not determinable from within the TC-SDLP, the metric was
twice determined; once based on the FER and finally based on time delays.
The work includes an extensive background study, which consists of space
standardisation, orbital physics, error detection and correction, space datalink
protocols, data throughput and culminating in the protocol stack design.
The project specific link budget calculation is presented. The optimal
segment length policy was mathematically determined.
Asimulation model of the TC-SDLP was used as a proof of concept for the
effective throughput and give a performance benchmark. Finally a TC-SDLP
implementation offers a real world performance demonstration. / AFRIKAANSE OPSOMMING: Die telekommunikasie skakel tussen ’n lae aardomwenteling (LEO) sateliet
en ’n plattelandse grondstasie met ’n nie-volg antenna, het ’n skakelkwaliteit
wat in ’n groot mate varieer en ’n kort kommunikasievenster. Die sateliet tree
op as ’n stoor- en- aanstuur node tussen grondstasies. Die TC-SDLP en ’n leêr
oordrag protokol (FTP) vorm ’n vlak protokol stapel, wat onnodige protokol
funksionaliteit en die gevolglike opkoste uitsluit. Kode aanwins, wat deur
die BCH FEC in die TC-SDLP, aangebring word, verbeter die skakelkwaliteit.
Die kern van hierdie tesis is ’n verbetering van die TC-SDLP om sodoende
die ware deurvoer van nuttige vragdata te maksimimeer. Hierdie verbetering
is bereik deur die skep van ’n optimale segmentlengte-seleksie metode
gebaseer of die bit fout tempo (BER).
Aangesien die BER nie bepaal kan word vanuit die TC-SDLP nie, is die
maatstaf twee keer bepaal; die eerste keer is die bepaling gebaseer op die
raamwerk fout tempo (FER) en die finale bepaling op tyd vertragings.
Die tesis sluit ’n omvattende agtergrondstudie in, wat bestaan uit ruimte
standardisering, wentelbaan fisika, die opspoor en regstel van foute, ruimte
inligtingskakel protokol en deurstuur van data wat uitloop op die protokol
ontwerp. Daar word aangedui hoe die berekening van die begroting vir die
skakel van toepassing op die spesifieke projek, gedoen is. ’n Wiskundige
analise van die optimale segmentlengte s ook gedoen.
’n Simulasie model van die TC-SDLP is gebruik as ’n bewys van die konsep
vir die ware deurset en gee ’n prestasie maatstaf. Laastens bied die TCSDLP
implementering ’n ware wereld prestasie demonstrasie.
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Σύστημα διόρθωσης λαθών βασισμένο σε κώδικες BCH και υλοποίηση σε FPGAMatalon, Isi 05 February 2015 (has links)
Σε μία εποχή όπου η ψηφιοποίηση δεδομένων έχει αυξηθεί ραγδαία η ανάγκη για τη βέλτιστη μετάδοσή τους είναι απαραίτητη. Από τα πλέον σημαντικά μέρη των προτύπων μετάδοσης είναι η κωδικοποίηση του καναλιού μέσω ειδικών αλγορίθμων ώστε να επιτευχθεί η εύρεση και διόρθωση τυχών λαθών. Οι κώδικες Bose, Chaudhuri και Hocquenghem (BCH) είναι τέτοιου είδους κώδικες που χρησιμοποιούνται ευρέως σε
εφαρμογές όπως τα CD, DVD, σκληροί δίσκοι, δίσκοι στερεάς κατάστασης (SSD) και το πρότυπο δορυφορικής μετάδοσης τηλεόρασης υψηλής ανάλυσης (HDTV), DVB-S2.
Στην παρούσα διπλωματική εργασία σχεδιάστηκε και υλοποιήθηκε κωδικοποιητής και αποκωδικοποιητής BCH για τις 11 περιπτώσεις κανονικού πλαισίου που προσφέρει το πρότυπο DVB-S2. Κύριος στόχος ήταν η όσο το δυνατόν καλύτερη υλοποίηση με γνώμονα το μέγεθος, με τη χρήση κοινών κυκλωμάτων και για τις 11 περιπτώσεις. Αποτέλεσμα αυτής της βελτιστοποίησης μεγέθους, ήταν κάποιες τεχνικές βελτιστοποίησης της ταχύτητας αποκωδικοποίησης, όπως το shortening, να μη χρησιμοποιηθούν καθώς θα είχαν ως αποτέλεσμα την αύξηση της επιφάνειας μερών του αποκωδικοποιητή κατά περίπου 11 φορές. Καθώς σκοπός της διπλωματικής ήταν η μελέτη της απόδοσης των κωδίκων BCH, μελετήθηκε ο ρυθμός λαθών σε διάφορες τιμές της αναλογίας ενέργειας – θορύβου (Eb / N0 ), αφού πρώτα υλοποιήθηκε σε FPGA. / The amount of digital information is growing rapidly the recent decades, making transmission optimization one of the top priorities in digital information systems. One of the main parts of every transmission standard is channel encoding, with the use of algorithms aimed at finding and correcting errors (Forward Error Correction – FEC). Such codes are Bose, Chaudhuri and Hocquenghem (BCH) code, which are widely
used in applications like CDs, DVDs, Hard Drives, Solid State Drives (SSDs) and DVB-S2, a satellite transmission standard mostly used for High Definition Television (HDTV).
This thesis sets out to account for the design and implementation of a BCH encoder and decoder for all 11 different code rates proposed by the DVB-S2 standard for normal frames. The design was area optimized in order for all 11 code rate encoders and decoders to work on the same FPGA. This lead to some optimization techniques being unused. Even though the codes are shortened, no shortening algorithms which aim at clock cycle optimization were used. Were they used, would lead parts of the decoder to be almost 11 times
larger. The main goal of the thesis is to analyze the performance of the codes, so the error rate was measured under different values of the energy to noise ratio (Eb/ N0 ).
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Ανάλυση της απόδοσης του Forward Error Correction σε κινητά δίκτυα επικοινωνιών τεχνολογίας Long Term EvolutionΚανάκης, Νικόλοας 06 October 2011 (has links)
Long Term Evolution (LTE) είναι το όνομα που έδωσε το 3GPP στο πρόγραμμα εξέλιξης των κινητών συστημάτων επικοινωνιών τρίτης γενιάς UMTS, με στόχο την αντιμετώπιση των μελλοντικών απαιτήσεων της αγοράς των κινητών δικτύων. Βασικοί στόχοι του νέου προτύπου LTE αποτελούν η αυξημένη απόδοση, το μικρότερο κόστος υλοποίησης, η μείωση της πολυπλοκότητας λειτουργίας και η παροχή νέων εξελιγμένων υπηρεσιών, κάνοντας χρήση νέων φασμάτων λειτουργίας. Οι προσδοκίες από το LTE είναι ιδιαίτερα υψηλές και βασίζονται στην παροχή υπηρεσιών απαλλαγμένων από τις απώλειες. Συνεπώς, η επιτυχία του LTE θα καθοριστεί από την ικανότητα παροχής κινητών συσκευών και ασύρματης υποδομής που θα ανταποκρίνονται στα πρότυπα του 3GPP και θα είναι ιδιαίτερα ανθεκτικά στις απώλειες της ασύρματης μετάδοσης, ώστε να προσφέρονται βελτιωμένες υπηρεσίες υψηλής απόδοσης.
Μία βασική πτυχή των προδιαγραφών του συστήματος LTE είναι η ενίσχυση της υπηρεσίας Multimedia Broadcast/Multicast Services, όπου το ίδιο περιεχόμενο μεταδίδεται σε πολλαπλούς χρήστες που βρίσκονται σε μία συγκεκριμένη περιοχή μετάδοσης της υπηρεσίας. Η υπηρεσία MBMS πρωτοπαρουσιάστηκε σαν ένα νέο χαρακτηριστικό στην έκδοση 6 του 3GPP, ώστε να προσφέρει broadcast και multicast μετάδοση πολυμεσικού περιεχομένου σε κινητούς χρήστες μέσω MBMS ασύρματων φορέων μετάδοσης. Η υπηρεσία MBMS παρέχει δύο διαφορετικές μεθόδους διανομής περιεχομένου, τη μέθοδο download και τη μέθοδο streaming. Για να υποστηρίξει την αποδοτική διανομή MBMS περιεχομένου, το 3GPP συμπεριέλαβε ένα μηχανισμό Forward Error Correction στο επίπεδο εφαρμογών (AL-FEC).
Το FEC είναι μία μέθοδος που προσφέρει έλεγχο λαθών κατά τη μετάδοση δεδομένων, η οποία χρησιμοποιείται για να υποστηρίξει ή να αντικαταστήσει άλλες μεθόδους παροχής αξιοπιστίας. Στο FEC, ο αποστολέας εισάγει πλεονάζουσα πληροφορία στη μετάδοση δεδομένων. Αυτή η πληροφορία επιτρέπει στο δέκτη να ανακατασκευάσει τα αρχικά δεδομένα. Τέτοια σχήματα αναπόφευκτα προσθέτουν ένα σταθερό overhead στα μεταδιδόμενα δεδομένα με αποτέλεσμα να είναι υπολογιστικά ακριβά. Παρόλα αυτά στα multicast πρωτόκολλα, η χρήση FEC τεχνικών προσφέρει πολύ ισχυρά κίνητρα. Η κωδικοποίηση μπορεί να εξαλείψει τις ανεξάρτητες απώλειες στους διαφορετικούς δέκτες. Επιπρόσθετα, η δραματική μείωση του ρυθμού απώλειας πακέτων μειώνει κατά ένα μεγάλο μέρος την ανάγκη επαναποστολής των χαμένων πακέτων από τον αποστολέα. Επομένως, οι FEC τεχνικές είναι πολύ εύκολο να εκπληρώσουν έναν πρωταρχικό σκοπό των multicast κινητών υπηρεσιών, που είναι η προσαρμοστικότητα σε εφαρμογές με μεγάλο αριθμό δεκτών. Αυτός είναι ο λόγος που το 3GPP συνιστά τη χρήση του AL-FEC για την υπηρεσία MBMS και πιο συγκεκριμένα, υιοθετεί τη χρήση των συστηματικών κωδίκων Raptor.
Λαμβάνοντας υπόψιν τα παραπάνω, στόχος της παρούσας μεταπτυχιακής διπλωματικής εργασίας είναι η μελέτη της απόδοσης του AL-FEC πάνω σε υπηρεσίες MBMS, εστιάζοντας στην υπηρεσία της streaming μεθόδου παράδοσης δεδομένων.
Προς αυτή την κατεύθυνση, στην παρούσα εργασία μελετάμε την εφαρμογή του μηχανισμού AL-FEC πάνω σε multicast streaming υπηρεσίες των LTE, διερευνώντας πως το ποσό της πλεονάζουσας πληροφορίας ποικίλλει σε πολλαπλούς χρήστες χρησιμοποιώντας ρεαλιστικά περιβάλλοντα προσομοίωσης. Επίσης, εξετάζουμε την απόδοση του AL-FEC για διάφορες διατάξεις του δικτύου ασύρματης πρόσβασης, διάφορα μοντέλα κινητικότητας των χρηστών καθώς και διάφορες παραμέτρους της FEC κωδικοποίησης. / Long Term Evolution (LTE) is the name given to a project within the Third Generation Partnership Project (3GPP) to improve the UMTS 3G mobile system standard to cope with future requirements. Goals include improving efficiency, lowering cost, reducing complexity and improving services, making use of new spectrum opportunities. Expectations are high for LTE and are based on the premise of fault-free performance. Therefore, LTE’s initial success will be determined by the ability of handset and radio infrastructure manufacturers to deliver products that conform to 3GPP standards and are robust enough to allow operators to introduce improved services.
A key aspect of LTE specifications is the enhancement of Multimedia Broadcast/Multicast Services (MBMS), where the same content is transmitted to multiple users located in a specific service area. MBMS was firstly standardized as a new feature in 3GPP Release 6, in order to broadcast and multicast multimedia content to mobile terminals via MBMS radio bearer. The MBMS provides two different delivery methods, the download delivery and the streaming delivery method. To support efficient download and streaming delivery, 3GPP has included Application Layer Forward Error Correction (AL-FEC) in the MBMS standard.
FEC is a method for error control for data transmission that is used to augment or replace other reliability methods. In FEC, the sender introduces redundant information in the data transmitted. This information allows the receiver to reconstruct the source data. Such schemes inevitably add a constant overhead in the transmitted data and are computationally expensive. In multicast protocols however, the use of FEC techniques has very strong motivations. The encoding eliminates the effect of independent losses at different receivers. This makes these schemes able to scale irrespectively of the actual loss pattern at each receiver. Additionally, the dramatic reduction in the packet loss rate largely reduces the need for retransmission of lost data from the sender. FEC schemes are therefore so simple as to meet a prime objective for mobile multicast services, which is scalability to applications with thousands of receivers. This is the reason why 3GPP recommends the use of AL-FEC for MBMS and, more specifically, adopts the use of systematic Raptor code.
After taking into account the above analysis, objective of this master thesis is the study of AL-FEC in MBMS, focusing on the streaming delivery method.
To this direction, in this work we study the application of AL-FEC for the streaming delivery method over LTE networks. We investigate how the amount of FEC overhead varies at multiple receivers using realistic simulation scenarios and we investigate the performance of AL-FEC overhead considering different cell deployments, user mobility models and FEC encoding parameters.
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THE EVALUATION AND INTEGRATION OF AN INSTRUMENTATION AND TELEMETRY SYSTEM WITH SOQPSK MODULATION AND CONTROL INTEGRATED WITH AVIONICS DISPLAYSWegener, John A., Zettwoch, Robert N., Roche, Michael C. 10 1900 (has links)
ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / This paper describes the integration activities associated with the instrumentation and telemetry system developed for an F/A-18 Hornet Flight Test program, including bench integration, avionics integration, and aircraft ground and flight checkout. The system is controlled by a Boeing Integrated Defense System (IDS) Flight Test Instrumentation designed Instrumentation Control Unit (ICU), which interfaces to an avionics pilot display and Ground Support Unit (GSU) to set up the instrumentation during preflight and control the instrumentation during flight. The system takes in MIL-STD-1553, analog parameters, Ethernet, Fibre Channel, and video, and records these with onboard recorders. Selected subsets of this data may be routed to the telemetry system, which features two RF streams, each of which contains up to four PCM streams combined into a composite by a data combiner. The RF streams are transmitted by multi-mode digital transmitters capable of PCM-FM or Shaped Offset Quadrature Phase Shift Keying (SOQPSK), with selectable Turbo-Product Code (TPC) Forward Error Correction (FEC). This paper describes integration of the system with the IDS Flight Test Integration Test Bench (ITB), production avionics integration facilities, and final aircraft ground checkout and initial flight tests. It describes results of integration activities and bench evaluation of the telemetry system.
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An LDPC error control strategy for low earth orbit satellite communication link applicationsOlivier, Francois Jacobus 12 1900 (has links)
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Low earth orbit (LEO) satellite communication presents a unique environment
which inherently di ers from most other communication channels.
Due to the varying orbital patterns of LEO satellites the link exhibits varying
link margins. Limited communication time windows need to be optimised to
maximise the volumetric data throughput.
Large coding gains can be obtained by the implementation of forward error
correction codes. This thesis presents a means for optimising the data
throughput of LEO satellite communication through the implementation of a
mission speci c error control strategy. Low density parity check (LDPC) codes
are versatile and present good error performances at many di erent code rates
and block lengths. With power limitations on the space segment and remote
ground stations, hardware utilisation e ciency must be optimised to reduce
power consumption. In response to this requirement, this thesis evaluates
various algorithms for LDPC decoders.
An iterative LDPC decoder, implementing an approximation algorithm,
is presented as a low complexity solution with good error performance. The
proposed solution provides a very good balance between required hardware
complexity and coding performance. It was found that many parameters of
the decoders and codes can be altered to allow the implementation of these
codes in systems with varying memory and processing capabilities. / AFRIKAANSE OPSOMMING: Kommunikasiekanale van satelliete met lae wentelbane, bied 'n unieke omgewing
wat inherent verskil van meeste ander kommunikasiekanale. As gevolg
van veranderende wentelbaanpatrone, vertoon die kanaal 'n wisselende foutgedrag.
Kommunikasievensters is beperk en moet geoptimeer word om die totale
deurset van die stelsel te maksimeer.
Groot koderingswinste kan verkry word deur die implementering van foutkorreksie
kodes. Hierdie tesis voorsien 'n metode om die datadeurset van
satelliete met lae wentelbaan te optimeer, deur middel van implementering
van 'n missie-spesi eke foutbeheer strategie. Lae digtheid pariteit toetskodes
(LDPC) is veelsydige kodes, bied goeie foutbeheer en is doeltre end vir verskillende
kodekoerse en bloklengtes. Met drywingsbeperkinge op die ruimtesegment
en afgesonderde grondstasies, moet hardeware komponente doeltreffend
gebruik word om drywingsverbruik te verminder. Ten einde aan hierdie
ontwerpsvereiste te voldoen, evalueer hierdie tesis verskeie LDPC dekodeerderalgoritmes.
Deur 'n iteratiewe LDPC dekodeerder met 'n benaderingsalgoritme te implementeer,
word 'n oplossing van lae kompleksiteit aangebied, maar wat steeds
goeie foutkorreksie eienskappe toon. Die voorgestelde oplossing bied 'n baie
goeie balans tussen benodigde hardeware kompleksiteit en koderingsprestasie.
Daar is gevind dat heelwat parameters van die dekodeerders en kodes aangepas
kan word, ten einde implementering in stelsels met 'n wye verskeidenheid van
geheuespasie en verwerkingsvermoëns moontlik te maak.
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Implementation of a protocol and channel coding strategy for use in ground-satellite applicationsWiid, Riaan 03 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: A collaboration between the Katholieke Universiteit van Leuven (KUL) and
Stellenbosch University (SU), resulted in the development of a satellite based
platform for use in agricultural sensing applications. This will primarily serve
as a test platform for a digitally beam-steerable antenna array (SAA) that was
developed by KUL. SU developed all flight - and ground station based hardware
and software, enabling ground to flight communications and interfacing with
the KUL SAA. Although most components had already been completed at the
start of this M:Sc:Eng: project, final systems integration was still unfinished.
Modules necessary for communication were also outstanding. This project
implemented an automatic repeat and request (ARQ) strategy for reliable file
transfer across the wireless link. Channel coding has also been implemented
on a field programmable gate array (FPGA). This layer includes an advanced
forward error correction (FEC) scheme i.e. a low-density parity-check (LDPC),
which outperforms traditional FEC techniques. A flexible architecture for
channel coding has been designed that allows speed and complexity trade-offs
on the FPGA. All components have successfully been implemented, tested and
integrated. Simulations of LDPC on the FPGA have been shown to provide
excellent error correcting performance. The prototype has been completed and
recently successfully demonstrated at KUL. Data has been reliably transferred
between the satellite platform and a ground station, during this event. / AFRIKAANSE OPSOMMING: Tydens ’n samewerkingsooreenkoms tussen die Katholieke Universiteit van
Leuven (KUL) en die Universiteit van Stellenbosch (US) is ’n satelliet stelsel
ontwikkel vir sensor-netwerk toepassings in die landbou bedryf. Hierdie stelsel
sal hoofsaaklik dien as ’n toetsmedium vir ’n digitaal stuurbare antenna
(SAA) wat deur KUL ontwikkel is. Die US het alle hardeware en sagteware
komponente ontwikkel om kommunikasie d.m.v die SAA tussen die satelliet en
’n grondstasie te bewerkstellig. Sedert die begin van hierdie M:Sc:Ing: projek
was die meeste komponente alreeds ontwikkel en geïmplementeer, maar
finale stelselsintegrasie moes nog voltooi word. Modules wat kommunikasie
sou bewerkstellig was ook nog uistaande. Hierdie projek het ’n ARQ protokol
geïmplementeer wat data betroubaar tussen die satelliet en ’n grondstasie
kon oordra. Kanaalkodering is ook op ’n veld programmeerbare hekskikking
(FPGA) geïmplementeer. ’n Gevorderde foutkorrigeringstelsel, naamlik ’n lae
digtheids pariteit toetskode (LDPC), wat tradisionele foutkorrigeringstelsels
se doeltreffendheid oortref, word op hierdie FPGA geïmplementeer. ’n Kanaalkoderingsargitektuur
is ook ontwikkel om die verwerkingspoed van data
en die hoeveelheid FPGA logika wat gebruik word, teenoor mekaar op te weeg.
Alle komponente is suksesvol geïmplementeer, getoets en geïntegreer met die
hele stelsel. Simulasies van LDPC op die FPGA het uistekende foutkorrigeringsresultate
gelewer. ’n Werkende prototipe is onlangs voltooi en suksesvol
gedemonstreer by KUL. Betroubare data oordrag tussen die satelliet en die
grondstasie is tydens hierdie demonstrasie bevestig.
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