System Architecture for C2C Communications Based on Mobile WiMAX Michiyo ASHIDA VTT Technical Research Centre of Finland

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 2MCO'08, Metz, France/Luxembourg OUTLINE  Background  Two types of Mobile WiMAX architecture  C2C communication difficulty with Mobile WiMAX  New architecture for C2C communication based on Mobile WiMAX  Conclusion & future work

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 3MCO'08, Metz, France/Luxembourg BACKGROUND

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 4MCO'08, Metz, France/Luxembourg NEEDS FOR A CITY-WIDE WIRELESS NETWORK FOR VEHICLES For vehicular services, such as localized weather & traffic services Requirements:  Wireless broadband connection Between car and base station, 1km Car-to-infrastructure (C2I) communication Directly with neighbors Car-to-car (C2C) communication  Real-time data delivery  User mobility improvement (60-100km/h)

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 5MCO'08, Metz, France/Luxembourg URBAN WLAN NETWORK EXAMPLE - panOULU Provided for free by City of Oulu, Finland Currently IEEE b/g (WLAN) Some mesh routers More than 1000 access points High throughput for stationary users ”Spot” type coverage Not meant for nomadic and mobile users

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 6MCO'08, Metz, France/Luxembourg CITY-WIDE MOBILE WiMAX NETWORK FOR HIGH-SPEED VEHICLES IEEE802.16e-2005 standard Broadband wireless metropolitan area networks for fixed and mobile nodes Advantages: Provides connection in a “wide-area”, not “spot” Intelligent MAC  Scheduling  Quality-of-Service (QoS) support  Large BS capacity Mobility management  Fast and seamless handover  Power management Security support  Protection of both control & data messages Support for smart antenna technologies

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 7MCO'08, Metz, France/Luxembourg REQUIREMENTS (RECAP)  Wireless broadband connection Between car and base station, 1km Car-to-infrastructure (C2I) communication Directly with neighbors Car-to-car (C2C) communication  Real-time data delivery  User mobility improvement (60-100km/h)

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 8MCO'08, Metz, France/Luxembourg TWO TYPES OF MOBILE WiMAX ARCHITECTURE

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 9MCO'08, Metz, France/Luxembourg MOBILE WiMAX - TWO TYPES OF NETWORK ARCHITECTURE Point-to-MultiPoint (PMP) Mode, Default Mesh Mode, Optional Central control by BS Node authentication Transmission scheduling Handover support Data encryption Crypto. key management One-hop communicationMulti-hop communication Traditional C2C approaches: Mesh/ad-hoc networking

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 10MCO'08, Metz, France/Luxembourg WHY NOT MESH? Coverage issue is not so important with Mobile WiMAX Problems with mesh: Less performance than single-hop Complex management of moving node in real-time Large amount of management traffic due to routing Compatibility issue (a single routing protocol) Unreliable connection depending on topology No WiMAX mesh products available yet 1000 packets 85% Successful delivery rate = 85% 614 packets xx=61.4% End-to-end delay = D p1 D p2 D p3 D h1 ++++

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 11MCO'08, Metz, France/Luxembourg TRANSMISSION SCHEDULING - TIME DIVISION DUPLEX (TDD) Duplexing is a technique to control use of shared resource (e.g. channel) Time intervals for downlink and uplink Collidions can be avoided by duplexing Frequency Time Downlink Uplink Channel f 1 Transmissions from BS Transmissions from Mobile Nodes (shared)

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 12MCO'08, Metz, France/Luxembourg C2C MODULE BASED ON PMP MODE

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 13MCO'08, Metz, France/Luxembourg FINDINGS FROM PMP MODE BS SourceDestination 12 Problem: Always routed through BS Requires two times of transmissions Addressing problem ? Radio is broadcast Neighbors can listen However, no direct communication is available Reason: lack of neighbor knowledge and routing decision module

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 14MCO'08, Metz, France/Luxembourg TRADITIONAL NEIGHBOR DETECTION ALGORITHMS HELLO based neighbor detection Handshake based neighbor detection Link-state aware neighbor detection Wireless Channel HELLO ACK Node BNode A Oh, Node B is my neighbor! REQ OK, Node A is my neighbor! PROBE Channel condition seems to be good!

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 15MCO'08, Metz, France/Luxembourg SYSTEM ARCHITECTURE FOR OPTIMIZED C2C COMMUNICATION BASED ON TDD Default 2-hop connection to BS is always available Optimized C2C only if available Node finds its neighbors by incoming packets from them  Phy information  Channel quality No increase of traffic  Uses existing packets Message exchange with BS (or others) Data

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 16MCO'08, Metz, France/Luxembourg WHAT IT SOLVES?

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 17MCO'08, Metz, France/Luxembourg WHAT OPTIMIZED C2C APPROACH SOLVES Enables C2I & C2C communication for high-speed vehicles in a large area Dramatically reduces data traffic (up to 50%, compared to traditional PMP) Localized broadcast may be possible

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 18MCO'08, Metz, France/Luxembourg WHAT ARE THE ADVANTAGES OF USING OPTIMIZED C2C APPROACH? Flexible & reliable routing Routing is optimized Default connection is always maintained Increases network performance Shorter delivery time, less packet loss Conserves bandwidth, speeds up downlink No extra packets due to routing Compatible with standard PMP mode Node management & scheduling by BS No complex routing

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 19MCO'08, Metz, France/Luxembourg FUTURE WORK & CONCLUSION

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 20MCO'08, Metz, France/Luxembourg FUTURE WORK & CONCLUSION Future work (performance analysis, security consideration) Problem: Needs for both C2I & C2C in a wide area, for the needs to detect and report incidents anywhere in a city Costly traditional C2C approaches Proposal of system architecture: Optimized C2C for Mobile WiMAX Benefits: Flexible and reliable routing, efficient neighbor detection Improves network performance Compatible with standard PMP mode

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 21MCO'08, Metz, France/Luxembourg THANK YOU! For more information: Michiyo ASHIDA

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 22MCO'08, Metz, France/Luxembourg

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 23MCO'08, Metz, France/Luxembourg CELLULAR & SATELLITE NETWORKS Cellular network Advantage Disadvantage Satellite network Advantage Disadvantage

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 24MCO'08, Metz, France/Luxembourg IEEE p Amendment to IEEE standard ”Dedicated short-range communications” for Intellegent Transport System (ITS) Between high-speed moving vehicles Between vehicle to roadside ”accesspoint” ”Spot” type coverage, not ”area” or ”city-wide” IEEE MAC is only suitable for ”local area network” Usage of the infrastructure is restricted to ITS applications only Can be used for “spot” type ITS applications such as toll collection

VTT TECHNICAL RESEARCH CENTRE OF FINLAND 25MCO'08, Metz, France/Luxembourg Mobile WiMAX PHY Data Rates Cite from WiMAX FORUM