Presentation on theme: "Tetsuya Arita and Fumio Teraoka"— Presentation transcript:
1A Fast Handover Mechanism Using Cross-Layer Collaboration for Mobile Networks in High-Speed Trains Tetsuya Arita and Fumio TeraokaGraduate School of Science and Technology, Keio University, Japan
2Introduction High-Speed Trains Passengers Business Spend long hours on a trainLess transferCan’t use all applications because of narrowbandBusinessDemands for monitoring the train using video streaming
3The Goal of this Research To provide the communication environment faster than 1 Gbps to High-speed trainThere are three requirements for the goalCommunication SpeedThe current wireless LAN technologies (WiFi and WiMAX) cannot satisfy this requirementSession ContinuityFast Handover Mechanism
4Communication Speed over 1Gbps Infrared Comm. Device (IR-CD)has been developed by Prof. Shinichiro Haruyama* and Railway Technical Research Institute* Graduate School of System Design and Management, Keio UniversityFront viewRear viewInfrared laserSerial InterfaceBeaconEthernet InterfaceSPECSpeed : 1.25 GbpsRange : 360mFeature : DirectionalPower cablePower SwitchReceive Level
5Session Continuity Network Mobility (NEMO) Basic Support [RFC3936] The network mobility protocol in IPv6Mobile Router (MR)executes handovers and provides mobile node with mobility-transparent connectivityHome Agent (HA)manages the binding of Home Address (HoA) and Care-of Address (CoA)Home network(4) CommunicationHoACorrespondent NodeMRHAMobile network(3)Foreign NetworkCoA(2)Mobile network(1)MovementMR(2) Register CoA and MNP with HA(3) IPv6–in IPv6 tunnel
6Fast Handover Mechanism Conventional Handover Proceduretakes more than 1 sec1. Waiting for receiving Router Advertisement (RA) message2. The Duplicate Address Detection (DAD) procedurenew ARHA(4) RA(6)BU(7)BA(3) wait for RA(5) DADNetwork LayerMobile NodeTotal disruption time (more than 1 sec)Link Layer(1) comm. quality getting worse(2) L2 handoverBU : Binding Update messageBA : Binding Acknowledgement message
7L3-Driven Fast Handover L3-Driven Fast Handover [RFC5184]Developed in our laboratoryUsing cross-layer collaborationWe defined link layer primitivesnew ARHA(8)BU(9)BA(4) pre-DADNetwork Layer(2) L2-LinkStatus Changed(3) L2-PoAList(7) L2-LinkUp(5) L2-Link ConnectMobile NodeTotal disruption time (10-15 ms)Link Layer(1) comm. quality getting worse(6) L2 handover
8Proposal: Fast Handover Mechanism For the IR-CD Eliminating DAD processing TimeDAD processIn case of WiFiIt is possible to predict handovers by Receive Signal Strength IndicatorExecute DAD before handoversIn case of IR-CDIt is impossible to predict handoversCannot execute DAD before handoverSingle administration organizationA Railway companyAssign each mobile router a unique interface identifierTherefore, the proposed mechanism disables DAD processingIn case of WiFi, execute DAD before handoverIt is possible to predict handover by RSSIIn case of IR-CD, it is impossible to execute DAD before handover
9Proposal: Fast Handover Mechanism For the IR-CD Eliminating Waiting Time to Detect Link Layer HandoverIn case of IR-CDMR and IR-CD are connected by Ethernet cableLink state between MR and IR-CD is always LinkUp stateIR-CD is regarded as a repeaterConnect IR-CD to MR with Data cable and Control cableControl cable can notify MR of the infrared link state (LinkUp/LinkDown)L3-Deriven Fast HandoverNotification of L2-LinkUpWiFi device can detect the link statusInfrared Comm. Device on the trainInfrared Comm. Device on the groundData cable(1 Gbps)Infrared LaserLinkUp/LinkDownControl cableTrain
10Proposal: Fast Handover Mechanism For the IR-CD The Proposed Procedurenew ARHA(5) RS(6) RA(7) BU(8) BANetwork Layer(2) L2-Linkdown(4) L2-LinkupMobile RouterTotal disruption timeLink Layer(1) Linkdown frame(3) Linkup frameInfrared communication device
11Implementation Environment OS : NetBSD 4.99 SHISA An implementation of Mobile IPv6 and NEMO BS on NetBSDfhod (fast handover daemon) on NetBSDDaemon to achieve fast handoverfhodmrdnemonetdMobility SocketRouting SocketkerneluserlandBindingUpdateDatabaseDestinationOptions headermoduleManagementNeighborDiscoveryAddressRouting tableRoutingtableTunnelingForwardingOur implementationModule diagram of our implementationbased on SHISA
13Evaluation – Handover Time - Test networkEmulate the train environmentIR-CDMRARHA1.7 msec0.3 msec4.0 msectrainground0.003msecLinkupRSRABUBADetails of Handover TimerouterHACNAR-1AR-2無線環境エミュレータにスクリプト読ませてる図列車の走行をエミュレートしている本研究室で開発したを明記scenarioWirelessEnvironmentEmulatorMRData cableControl cableCN: Correspondent NodeLFN: Local Fixed NodeLFN
14Evaluation – Packet Loss Ratio - configuration10 IR-CDs are connected to a single ARa handover occurs per 5 secondsA train runs at 300km/h and IR-CD is installed every 420ma L3 Handover occurs in 10 handoverspacket loss never occurs on the infrared linkL2 handover time10ms, 50ms, 100msRTT between MR and HA0 – 30 msUDP packet were sent form CN to MR at 1 Mbpsハンドオヴぁ時間の単位仮に１００msでもEven in the worst case,The average packet loss ratio is about 2%.
15Conclusion The goal of this research To provide the mobile network in high-speed train with high-speed connectivity (more than 1 Gbps)We proposed a fast handover mechanismUsing cross-layer collaboration for mobile network installed in High- speed trainDefined the Linkup control frameMR can immediately start handover procedureThe measurements show thathandover time is approximately 6.0ms + L2 handover timepacket loss ratio is approximately 2 % in the worst case.