Research On Simulation And Implementation Of Distributed Fountain Codes In Deep Space Communication

Deep space exploration is one of the most important efforts ofhuman to explore the unknown universe, and communications in thedeep space has become an important research direction in this field.However, it’s quite difficult to ensure the reliability andefficiency in deep space. The technologies widely used intraditional networks cannot meet the transmission needs of deepspace communications.Fountain codes have low complexity encodingand decoding algorithm. Distributed LT code is a novel encodingprocedure which has better performance in multi-source model.In this paper, the first part introduces the basic principlesof distributed LT codes,includingthetechniques to decomposeLTcodes intodistributedLT codesin two-source single-sink network andfour-source single-sink network which are abstracted from realnetworks. Lastly it introduces an improved decomposition techniquefor lossy source-relay links.The second part is simulations andimplementations. Firstly itsimulates distributed LT codes with DSDdistribution under different conditions. Secondly it develops acomplete protocol stack, which chooses D-FDP andprovesexcellentperformance of distributed LT codes and D-FDP protocol underconditions of deep space.What’s new in this paper is that firstly it uses NS3as thesimulation platform to build a virtual network topology, configureparameters of links, andsimulate distributed LT codes and D-FDPunder different conditions; secondly it uses hardware platforms asnetwork nodes and readingephemeros files to simulate the orbits ofstar or relays, developsa complete protocol stack, which choosesD-FDP, based on distributed LT codes, as application protocol andthen runs it on these hardware nodes, thus proves that DistributedLT codes can satisfy the reliability requirement of communicationsin deep space.