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A Fast Handover Mechanism Using Cross-Layer Collaboration for Mobile Networks in High-Speed Trains Tetsuya Arita and Fumio Teraoka Graduate School of Science.

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Presentation on theme: "A Fast Handover Mechanism Using Cross-Layer Collaboration for Mobile Networks in High-Speed Trains Tetsuya Arita and Fumio Teraoka Graduate School of Science."— Presentation transcript:

1 A Fast Handover Mechanism Using Cross-Layer Collaboration for Mobile Networks in High-Speed Trains Tetsuya Arita and Fumio Teraoka Graduate School of Science and Technology, Keio University, Japan 1

2 Introduction High-Speed Trains Passengers Spend long hours on a train Less transfer Cant use all applications because of narrowband Business Demands for monitoring the train using video streaming 2

3 The Goal of this Research To provide the communication environment faster than 1 Gbps to High-speed train There are three requirements for the goal Communication Speed The current wireless LAN technologies (WiFi and WiMAX) cannot satisfy this requirement Session Continuity Fast Handover Mechanism 3

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 University SPEC Speed : 1.25 Gbps Range : 360m Feature : Directional Beacon Infrared laser Receive Level Power Switch Power cable Serial Interface Ethernet Interface Front viewRear view 4

5 Session Continuity Network Mobility (NEMO) Basic Support [RFC3936] The network mobility protocol in IPv6 Mobile Router (MR) executes handovers and provides mobile node with mobility-transparent connectivity Home Agent (HA) manages the binding of Home Address (HoA) and Care-of Address (CoA) Mobile network Home network Mobile network HA Correspondent Node Foreign Network MR CoA HoA (1)Movement (2) Register CoA and MNP with HA (1) (2) (3) IPv6–in IPv6 tunnel (3) (4) Communication 5

6 Fast Handover Mechanism Conventional Handover Procedure takes more than 1 sec 1. Waiting for receiving Router Advertisement (RA) message 2. The Duplicate Address Detection (DAD) procedure Mobile Node Network Layer Link Layer (1) comm. quality getting worse (2) L2 handover (3) wait for RA new AR (4) RA (5) DAD HA (6)BU(7)BA Total disruption time (more than 1 sec) BU : Binding Update message BA : Binding Acknowledgement message 6

7 L3-Driven Fast Handover L3-Driven Fast Handover [RFC5184] Developed in our laboratory Using cross-layer collaboration We defined link layer primitives Mobile Node Network Layer Link Layer (1) comm. quality getting worse (6) L2 handover new AR HA (8)BU(9)BA (2) L2-LinkStatus Changed (4) pre-DAD (5) L2-Link Connect (3) L2-PoAList(7) L2-LinkUp Total disruption time (10-15 ms) 7

8 Proposal: Fast Handover Mechanism For the IR-CD Eliminating DAD processing Time DAD process In case of WiFi It is possible to predict handovers by Receive Signal Strength Indicator Execute DAD before handovers In case of IR-CD It is impossible to predict handovers Cannot execute DAD before handover Single administration organization A Railway company Assign each mobile router a unique interface identifier Therefore, the proposed mechanism disables DAD processing 8

9 Proposal: Fast Handover Mechanism For the IR-CD Eliminating Waiting Time to Detect Link Layer Handover In case of IR-CD MR and IR-CD are connected by Ethernet cable Link state between MR and IR-CD is always LinkUp state IR-CD is regarded as a repeater Connect IR-CD to MR with Data cable and Control cable Control cable can notify MR of the infrared link state (LinkUp/LinkDown) Data cable(1 Gbps) Control cable LinkUp/LinkDown Train Infrared Comm. Device on the train Infrared Comm. Device on the ground 9 Infrared Laser

10 Proposal: Fast Handover Mechanism For the IR-CD The Proposed Procedure Mobile Router Network Layer Link Layer (1) Linkdown frame new AR HA Total disruption time (3) Linkup frame (2) L2-Linkdown(4) L2-Linkup (5) RS(6) RA(7) BU(8) BA Infrared communication device 10

11 Implementation Our implementation Module diagram of our implementation based on SHISA Environment OS : NetBSD 4.99 SHISA An implementation of Mobile IPv6 and NEMO BS on NetBSD fhod (fast handover daemon) on NetBSD Daemon to achieve fast handover fhodmrdnemonetd Mobility Socket Routing Socket kernel userland Binding Update Database Destination Options header module Binding Management module Neighbor Discovery module Address Management module Routing table Management module Binding Update Database Routing table Tunneling module Forwarding module 11

12 Message Flow Message Flow in L3 Handover IR-CD MR fhodmrdnemonetd Train Prev. ARnew AR HA Link disconnected (1)Linkdown (3)Linkup (5) RS (6) RA Tunnel estab. tunnel (7) BU (8) BA Link connected 12

13 Evaluation – Handover Time - Test network Emulate the train environment Wireless Environment Emulator Control cable CN: Correspondent Node LFN: Local Fixed Node scenario Data cable LFN MR AR-1 AR-2 CN router HA IR-CDMRARHA 1.7 msec 0.3 msec 4.0 msec train ground 0.003msec Linkup RS RA BU BA Details of Handover Time 13

14 Evaluation – Packet Loss Ratio - configuration 10 IR-CDs are connected to a single AR a handover occurs per 5 seconds A train runs at 300km/h and IR-CD is installed every 420m a L3 Handover occurs in 10 handovers packet loss never occurs on the infrared link L2 handover time 10ms, 50ms, 100ms RTT between MR and HA 0 – 30 ms UDP packet were sent form CN to MR at 1 Mbps Even in the worst case, The average packet loss ratio is about 2%. 14

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 mechanism Using cross-layer collaboration for mobile network installed in High- speed train Defined the Linkup control frame MR can immediately start handover procedure The measurements show that handover time is approximately 6.0ms + L2 handover time packet loss ratio is approximately 2 % in the worst case. 15

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