NetworkCodingIntroduction網(wǎng)絡(luò)編碼簡(jiǎn)介專家講座

NetworkCodingIntroduction

鄭晗谞.11.12andyhanxu@163.comCI.HFUTNetworkCodingIntroduction網(wǎng)絡(luò)編碼簡(jiǎn)介專家講座第1頁(yè)NetworkCodingIntroduction1HowdowefindNetworkCoding?2HowtouseNetworkCoding?3WhydoweuseNetworkCoding?NetworkCodingIntroduction網(wǎng)絡(luò)編碼簡(jiǎn)介專家講座第2頁(yè)1HowdowefindNetworkCoding?

Ahaspacketsa,bandwantstosendbothofthemtoF,G.1.TraditionalRoutingThroughput:(2+1)/2=1.5/pernode2.UsingNetworkCodingThroughput:(2+2)/2=2/pernode

ThroughputGain:33%ABCDEFGNetworkCodinginButterflyNetworkABCDEFGABCDEFGaaaaaaaabbbbabbbbbaaaa⊕ba⊕ba⊕bbbbNetworkCodingIntroduction網(wǎng)絡(luò)編碼簡(jiǎn)介專家講座第3頁(yè)1HowdowefindNetworkCoding?AandCwanttoexchangepackets.1.TraditionalRouting:A-B,B-C,C-B,B-Acost4transmissionslots.2.UsingNetworkCoding:A-B,C-B,B-A/Ccost3transmissionslots.Ahasapacket:a;Chasapacket:cAfterBreceivesbothaandc,itbroadcastsa⊕cthusAcandecodecbya⊕(a⊕c);Ccandecodeabyc⊕(a⊕c)ThroughputGain:33%BCANetworkCodinginWirelesstwo-wayRelaychannelNetworkCodingIntroduction網(wǎng)絡(luò)編碼簡(jiǎn)介專家講座第4頁(yè)2HowtouseNetworkCoding?eg.RandomNetworkCodingABCEa,bba,bblostalostaABCEa,bba,bblostaencodea,btoa+band2a+blosta+bdecodeabyband2a+bNetworkCodingIntroduction網(wǎng)絡(luò)編碼簡(jiǎn)介專家講座第5頁(yè)RandomNetworkCodingAencodesa,btoXia+Yib=Ci(i=1,2)DencodesXia+Yib=CitoX3(X1a+Y1b)+Y3(X2a+Y2b)=C3Decode:eg.Fcandecodea,bfromX1a+Y1b=C1X3(X1a+Y1b)+Y3(X2a+Y2b)=C3

Notethateverycoefficientisrandomchoosenandtransmitted.ABCDEFGa,bX1a+Y1b=C1X2a+Y2b=C2X3(X1a+Y1b)+Y3(X2a+Y2b)=C3NetworkCodingIntroduction網(wǎng)絡(luò)編碼簡(jiǎn)介專家講座第6頁(yè)OpportunisticCodingandListeningAandE/CandDwanttoexchangepackets.1.NCwithoutopportunisticlisteningcost6transmissionslots2.NCusingopportunisticlisteningcost5transmissionslots

ThroughputGain:25%Byusingopportunisticlistening,allofthefournodeshas3packetstodecodefromthebroadcastedpackets:a⊕c⊕d⊕e

eg:Adecodeebya⊕c⊕d⊕(a⊕c⊕d⊕e)=eNodeBusesopportunisticcodingNodeACDEuseopportunisticlisteningABCDE4NodeRelayNetworkNetworkCodingIntroduction網(wǎng)絡(luò)編碼簡(jiǎn)介專家講座第7頁(yè)NetworkCodingusingMIMO1.NCusingopportunisticlisteningcost5transmissionslots2.NCusingMIMOcost3transmissionslots

ThroughputGain:66%ByusingMIMO,AandEcansendpacketsaandetoBsimultaneously;CandD,respectively.Bcanbroadcasta⊕etoAandE,andc⊕dtoCandDsimultaneouslybyusingMIMO.ABCDE4NodeRelayNetworkNetworkCodingIntroduction網(wǎng)絡(luò)編碼簡(jiǎn)介專家講座第8頁(yè)Coding-AwareRouting1.TraditionalroutingF-A:F-D-C-B-AA-I:A-B-C-E-I;I-F:I-H-G-Ftotalnumberoftransmission:112.NCwithtraditionalroutingtotalnumberoftransmission:10

EncodeatnodeB3.NCusingcoding-awareroutingI-F:I-E-C-D-Ftotalnumberoftransmission:4+4+4-3=9

EncodeatnodeB,D,E

ThroughputGain:11%FABCDEGHI3Flows:F-A;A-I;I-FNetworkCodingIntroduction網(wǎng)絡(luò)編碼簡(jiǎn)介專家講座第9頁(yè)Question:isthatall?Bhaspacketb;Dhaspacketd;Ehaspackete;1.NoNC:totalnumberoftransmission:62.UsingNC:AfterCreceivespackets:b,d,efirstbroadcasts:b⊕ethenbroadcasts:d⊕e

E:e⊕(b⊕e)=b;D:d⊕(d⊕e)=e;B:b⊕(b⊕e)⊕(d⊕e)=d.totalnumberoftransmission:5ThroughputGain:20%FABCDEGHI3Flows:F-A;A-I;I-FNetworkCodingIntroduction網(wǎng)絡(luò)編碼簡(jiǎn)介專家講座第10頁(yè)3WhydoweuseNetworkCoding?

BCABroadcastmodelX23X56X8X12X4X6X89AC1.TraditionalARQnumberofretransmission:62.UsingNCnumberofretransmission:4ReliablityGain:50%NetworkCodingIntroduction網(wǎng)絡(luò)編碼簡(jiǎn)介專家講座第11頁(yè)3WhydoweuseNetworkCoding?

BCABroadcastmodelX23X56X8X12X4X6X89ACImprovedmethodusingNC:AsretransmissionstillcannotguaranteecorrectlyreceptionbynodeAandC,ifeitheroneofthenodescorrectlyreceivestheretransmission,whiletheotheronedoesn't.Anewcombinedpacketswillbesent.eg.IfnodeAreceived1⊕3anddecode1by3⊕(1⊕3),whileCmissed.Anewcombinedpackets3⊕4willbesent.NetworkCodingIntroduction網(wǎng)絡(luò)編碼簡(jiǎn)介專家講座第12頁(yè)