Presentation on theme: "Tetsuya Arita and Fumio Teraoka"— Presentation transcript:
1 A 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
2 Introduction 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
3 The 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
4 Communication 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
5 Session 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
6 Fast 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
7 L3-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
8 Proposal: 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
9 Proposal: 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
10 Proposal: 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
11 Implementation 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
13 Evaluation – 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
14 Evaluation – 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%.
15 Conclusion 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.