Network Coding Introduction网络编码简介.ppt

NetworkCodingIntroduction 郑晗谞2013 11 12andyhanxu CI HFUT NetworkCodingIntroduction 1HowdowefindNetworkCoding 2HowtouseNetworkCoding 3WhydoweuseNetworkCoding 1HowdowefindNetworkCoding Ahaspacketsa bandwantstosendbothofthemtoF G 1 TraditionalRoutingThroughput 2 1 2 1 5 pernode2 UsingNetworkCodingThroughput 2 2 2 2 pernodeThroughputGain 33 NetworkCodinginButterflyNetwork a a a a a a a a b b b b a b b b b b a a a a b a b a b b b b 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 NetworkCodinginWirelesstwo wayRelaychannel 2HowtouseNetworkCoding eg RandomNetworkCoding encodea btoa band2a b losta b decodeabyband2a b RandomNetworkCoding Aencodesa 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 C3Notethateverycoefficientisrandomchoosenandtransmitted A B C D E F G a b X1a Y1b C1 X2a Y2b C2 X3 X1a Y1b Y3 X2a Y2b C3 OpportunisticCodingandListening AandE CandDwanttoexchangepackets 1 NCwithoutopportunisticlisteningcost6transmissionslots2 NCusingopportunisticlisteningcost5transmissionslotsThroughputGain 25 Byusingopportunisticlistening allofthefournodeshas3packetstodecodefromthebroadcastedpackets a c d eeg Adecodeebya c d a c d e eNodeBusesopportunisticcodingNodeACDEuseopportunisticlistening 4NodeRelayNetwork NetworkCodingusingMIMO 1 NCusingopportunisticlisteningcost5transmissionslots2 NCusingMIMOcost3transmissionslotsThroughputGain 66 ByusingMIMO AandEcansendpacketsaandetoBsimultaneously CandD respectively Bcanbroadcasta etoAandE andc dtoCandDsimultaneouslybyusingMIMO 4NodeRelayNetwork Coding AwareRouting 1 TraditionalroutingF A F D C B AA I A B C E I I F I H G Ftotalnumberoftransmission 112 NCwithtraditionalroutingtotalnumberoftransmission 10EncodeatnodeB3 NCusingcoding awareroutingI F I E C D Ftotalnumberoftransmission 4 4 4 3 9EncodeatnodeB D EThroughputGain 11 3Flows F A A I I F Question isthatall Bhaspacketb Dhaspacketd Ehaspackete 1 NoNC totalnumberoftransmission 62 UsingNC AfterCreceivespackets b d efirstbroadcasts b ethenbroadcasts d eE e b e b D d d e e B b b e d e d totalnumberoftransmission 5ThroughputGain 20 3Flows F A A I I F 3WhydoweuseNetworkCoding B C A Broadcastmodel A C 1 TraditionalARQnumberofretransmission 62 UsingNCnumberofretransmission 4ReliablityGain 50 3WhydoweuseNetworkCoding B C A Broadcastmodel A C ImprovedmethodusingNC AsretransmissionstillcannotguaranteecorrectlyreceptionbynodeAandC ifeitheroneofthenodescorrectlyreceivestheretransmission whiletheotheronedoesn t Anewcombinedpacketswillbesent eg IfnodeAreceived1 3anddecode1by3 1 3 whileCmissed Anewcombinedpackets3 4willbesent BalanceFlow BandwidthUtilizationGain a b a b a b a b a b a b a b a b a b a a a b a b a b a b a b b b a b a b 2 5 10bit 1 9 9bit PerformanceGai