Rural e-mail system for the Sumbandila satellite

Cooke, Adrian (Adrian Gerard)
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Stellenbosch : Stellenbosch University
ENGLISH ABSTRACT: Keywords: digital signal processing, OSI layer, network protocols, embedded systems, satellite technology This thesis describes the design and implementation of a rural e-mail system for the Sumbandila satellite. The rural e-mail system was developed during a project sponsored by the Department of Communications of the South African government. The complete Open Systems Interconnect (OSI) layer structure of the protocol architecture used on the satellite hardware and software is described. The equivalent implementation of the OSI layer on the ground station hardware is given. This includes the adaptation of the soundmodem Open Source Software modem to work for the e-mail system’s OSI layer. The design of the Application Layer e-mail system is described and the implementation of this design using the Python, Korn Shell and C programming environments is also given. The procedures used to test the system for reliability and the use of a database to create detailed logs of the e-mail system is shown to have generated a reliable system that is easily maintained. A critical evaluation of the system is provided in the last chapter.
AFRIKAANSE OPSOMMING: Sleutelwoorde: Syferseinverwerking, OSI-lae, netwerkprotokolle, toegewyde stelsels, satelliettegnologie Hierdie tesis beskryf die ontwerp en implementering van ’n plattelandse e-posstelsel vir die Sumbandila satelliet. Die plattelandse e-posstelsel is ontwikkel in opdrag van die Departement van Kommunikasie van die Suid-Afrikaanse regering. Die volledige Open Systems Interconnect (OSI) laagstruktuur van die protokol-argitektuur wat in die satelliet se apparatuur en programmatuur gebruik is, word beskryf. Die ekwivalente implementering van die OSI-laag op die grondstasie-apparatuur word gegee, insluitende die aanpassing van soundmodem, ’n oopbronkode sagteware-modem. Hierdie sagteware-modem word gebruik in die e-posstelsel se fisiese laag. Die ontwerp van die toepassingslaag van die e-posstelsel word beskryf, asook die implementering van hierdie ontwerp met behulp van Python, die Korninterpreteerder en C. Die prosedures waarvolgens stelselbetroubaarheid getoets is, en die gebruik van ’n databasis om noukeurige joernale van e-postransaksies te hou, demonstreer dat ’n betroubare, onderhoubare stelsel gemplementeer is. In die laaste hoofstuk word die stelsel krities geevalueer.
Thesis (MScIng)--University of Stellenbosch, 2007.
Electronic mail systems, Signal processing -- Digital techniques, Artificial satellites in telecommunication, Theses -- Electronic engineering, Dissertations -- Electronic engineering