自我介绍Thankyou,Mr./Ms.Chair./professorMynameissangqian.Iamveryhonoredtobeheretodooralpresentation.IamaMasterstudentfromHohaiUniversityandIamcurrentlydoingsomeresearchonphysicallayersecurity.Today,Iwouldliketosharewithyousomeofmyresearchonrelayselectionincooperativecommunication.(external/ekˈstərnəl;ɪkˈstərnəl/)内容安排：Mypresentationincludesthesefiveparts.First,somebackgroundinformationaboutthisresearch;Second,systemmodelwehavedone;Third,NN-basedrelayselectionschemewehaveproposedForth,SimulationandresultsanalysisAndlast,someconclusionswehavegotP4Partone,introductionFirstly,Iwouldliketogiveyouabitofbackground.Differingfromthetraditionalcryptographictechniquesbasedonsecretkeys,wecanmakeuseofwirelesschannelcharacteristicstoenhancephysicallayersecurity.Cooperativecommunicationhasbeenwidelyrecognizedasaneffectivewaytocombatwirelessfadingandprovidediversitygainwhichisoneoftheresearchhotspots.Machinelearningasanemergingtechnologyhasbeenwidelyappliedinimageprocessing,cancerprediction,stockanalysisandotherfields.Sowhynottryitinwirelesscommunication?P5:Next,IwanttotalkalittlebitaboutpresentstudyRecentstudiesondeeplearningforwirelesscommunicationsystemshaveproposedalternativeapproachestoenhancecertainpartsoftheconventionalcommunicationsystemsuchasmodulationrecognition、channelencodinganddecoding、channelestimationanddetectionandanautoencoderwhichcanreplacethetotalsystemwithanovelarchitecture【modulationrecognition:AnNNarchitectureformodulationrecognitionthatconsistsofa4-layerNNandtwotwo-layerNNs。channelencodinganddecoding：AplainDNNarchitectureforchanneldecodingtodecodekbitsmessagesfromNbitsnoisycodewords。channelestimationanddetection：Adense-Netforsymbol-to-symboldetectioncanadoptlongshort-termmemory(LSTM)todetectanestimatedsymbol.Autoencoder：theautoencodercanrepresenttheentirecommunicationsystemandjointlyoptimizethetransmitterandreceiveroveranAWGNchannel.】P6Sowhydidweconductthisresearch?Well,wewanttoexploitthepotentialbenefitsofdeeplearninginenhancingphysicallayersecurityincooperative(/kəʊ'ɒpərətɪv/wirelesscommunicationandreducethefeedbackoverheadinlimitedspectrumresoucebyourourproposedscheme.P8Nowletmemoveontoparttwo-systemmodelHere,youcanseeafigurewhichisasystemmodel.Thisisthesource;thesearetherelaynodesandthisisthedestination,thisistheeavesdropperThewholeprocessofcooperativewirelesscommunicationcanbedividedintotwophases.Inthefirstphase,thesourcebroadcaststhesignaltotheoptimalrelaywhichguaranteesperfectsecurity.AsshowninFig1,representsafadingcoefficientofthechannelfromthesourcetotherelaynode(.)Inthesecondphase,theoptimalrelayforwardsascaledversionofitsreceivedsignaltothedestinationinthepresenceoftheeavesdropper,wheretheoptimalrelayisconsideredtoadoptamplify-and-forward(AF)relayscheme.Inthisfigure,representsafadingcoefficientofthechannelfromtherelaytothedestinationrepresentsafadingcoefficientofthechannelfromtherelaytotheeavesdropper.P9:Hereyoucanseesomefollowingexpressions.Iamnotgoingtowasteourprecioustimeonthelengthyderivation.Iwouldliketoinviteyoutodirectlytakealookattheequationinitsfinalform.Thisistheoptimalindexoftheselectedrelaywiththeconventionalrelayselectionscheme.Amaongthisexpressionrepresentstheachievablesecrecyrateofsystemmodelwhentherelayisselected.P11Nowletmemovetopartthree-----NN-basedRelaySelectionHereyoucanseeafigurewhichshowsconventional3-la...
