Volumetric data throughput optimisation bydynamic FEC bearing frame lengthadaptation

[摘要] ENGLISH ABSTRACT: The telecommunications link between a LEO satellite and a rural ground stationwith a non-tracking antenna, has a strongly varying link quality anda short communications window. The satellite acts as a store-and-forwardnode between ground stations. The TC-SDLP and an FTP protocol form ashallow protocol stack, which excludes unneeded protocol functionality andthe 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 effectivepayload data throughput, or goodput. This improvement was achievedby creating an optimal segment length selection metric based on the BER.Since the BER is not determinable from within the TC-SDLP, the metric wastwice determined; once based on the FER and finally based on time delays.The work includes an extensive background study, which consists of spacestandardisation, orbital physics, error detection and correction, space datalinkprotocols, data throughput and culminating in the protocol stack design.The project specific link budget calculation is presented. The optimalsegment length policy was mathematically determined.Asimulation model of the TC-SDLP was used as a proof of concept for theeffective throughput and give a performance benchmark. Finally a TC-SDLPimplementation offers a real world performance demonstration.

[发布机构] Stellenbosch University