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V2V and V2I Communication

V2V and V2I Communication. 건국대학교 MBC Lab. Contents. V2I/V2V Communication Introduction. DSRC. WAVE. CALM. V2V Network Protocols. Projects and Standards. V2I/V2V Communication Introduction. Introduction. What is ITS? Intelligent Transportation Systems

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V2V and V2I Communication

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  1. V2V and V2I Communication 건국대학교 MBC Lab

  2. Contents V2I/V2V Communication Introduction DSRC WAVE CALM V2V Network Protocols Projects and Standards

  3. V2I/V2V Communication Introduction

  4. Introduction • What is ITS? • Intelligent Transportation Systems • encompass a broad range of wireless and wireline communications-based information, control and electronics technologies • can provide : • help monitor • manage traffic flow • reduce congestion • provide alternate routes to travelers • enhance productivity • save lives, time and money

  5. Introduction • V2V/V2I Service Perspective ITS will be developed into next-generation Navigation, Safety, Convergence & Infotainment Services - Next-generation Navigation : Provide real time and bi-directional information - Safety : Anti-collision and safety service in intersection road - Convergence : Vehicle management and related services - Infotainment Service : Content download service such as movie and music V2V/V2I Communication Technology • V2V Multi-hop Communication : Safety, Group communication • V2I Communication : Convergence, Infotainment service

  6. Introduction • V2V Communication : Vehicle Multi-hop Networking • V2I Communication : Bi-directional Packet Communication RSE : Road Side Equipment TSP : Telematics Service Provider Cellular/WiBroBase-station TSP Server IPBackbone V2I GPS V2V RSE RSE Emergence Message Warning Message Warning Message Probe Data Real time Traffic Information Accident Occur

  7. Introduction (Examples-1) • WISDOM(V2I) Management - Traffic signal control (Optimization for bus, emergency car) - Driving speed control Information - Data Collection- Information Provision- Provide information to traffic information center Safety - Accident Avoidance

  8. Introduction (Examples-2) • VII(Vehicle Infrastructure Integration ) • Traffic signal violation warning • Public safety vehicle priority signal activation • Provide traffic information

  9. DSRC

  10. DSRC • What is DSRC (Dedicated Short Range Communications)? • an Transportation Specific Technology • a short to medium range (1000m max generally 300m) communications service • supports both Public Safety and Private operations (roadside to vehicle, vehicle to vehicle communication) • provide very high data transfer (6-27 Mbps) rates where minimizing latency in the communication link • Half duplex : One-way at a time • for ITS applications, working in the 5.9 GHz band (U.S.) or 5.8 GHz band (Japan, Europe)

  11. DSRC • Technical Characteristics • 5.850 to 5.925 GHz • Bandwidth = 75 MHz • Shared, but Transportation is primary

  12. DSRC • Operating Characteristics • IEEE 802.11p protocol • Vehicle speeds up to 100 mph (160km/h) • Low latency: 50 ms • Application priority: 8 levels • Channel 172: vehicle safety only • Security • Encrypt using Public Key Infrastructure (PKI) • Road Side Unit (RSU) Authentication • On Board Unit (OBU) Privacy

  13. DSRC • DSRC Standards • ASTM E2213 : Radio (Data Link) New IEEE 802.11p • IEEE 1609-1 : Application manager • IEEE 1609-3 : Network service • IEEE 1609-4 : Medium Access Control • IEEE 1556 : Security

  14. WAVE (IEEE 802.11p)

  15. WAVE • What is WAVE? • IEEE 1609 - Family of Standards for Wireless Access in Vehicular Environments • Focused on following issues: • Limitation of the lack of ubiquitous high-speed communications between vehicles and service provider • Limitation of the lack of homogeneous communications interfaces between different automotive manufacturers • define an architecture and standardized set of services and interfaces • enable secure vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I)

  16. WAVE • consists of four standards: • IEEE P1609.1 - Resource Manager • specifies the services and interfaces of the WAVE Resource Manager application • defines data flows and resources • defines command message formats and data storage formats • specifies the types of devices that may be supported by the OBU(On Board Unit) • IEEE P1609.2 - Security Services for Applications and Management Messages • defines secure message formats and processing • IEEE P1609.3 - Networking Services • defines network and transport layer services • defines Wave Short Messages • IEEE P1609.4 - Multi-Channel Operations • provides enhancements to the IEEE 802.11 Media Access Control (MAC) to support WAVE operations

  17. WAVE • characteristic • Max. Speed : 200Km/H • 1000 m range must support 1 Mbps • Approach : Active • Bandwidth : 75 MHz (5.850 - 5.925 GHz) • Modulation : QPSK OFDM • Channels : 7EA 10 MHz channels • Data Rate : • 10 MHz Channels : 6, 9, 12, 18, 24, and 27 Mbps • 20 MHz Channels : 6, 9, 12, 18, 24, 36, 48, and 54 Mbps • Max Tx Pwr : 28.8 dBm (at the antenna input) • RSU and OBU Sensitivity : • 82 dBm (QPSK) / - 65 dBm (64QAM)

  18. WAVE • WAVE : Scope

  19. WAVE • Protocol Stack MLME : MAC Layer Management Entity PLME : Physical Layer Management Entity WME : WAVE Management Entity WSMP : WAVE Short Message Protocol

  20. WAVE • OSI versus WAVE Model • Draft P802.11p: Wireless Access in Vehicular Environments (WAVE) • Defines the lower layers (PHY and MAC) communications stack • IEEE Std 1609.4™-2007: Trial-Use Standard for WAVE - Multi-Channel Operation • Provides frequency band coordination and management within the MAC layer • IEEE Std 1609.3™-2007: Trial-Use Standard for WAVE - Networking Services • Specifies operation and management of the communications stack WAVE Standard

  21. CALM (Continuous Air interface for Long and Medium range)

  22. CALM • What is CALM? • Continuous Air interface for Long and Medium range • ISO approved framework • Provide heterogeneous packet-switched communication in mobile environments • CALM framework supports user transparent continuous communications across various interfaces and communication media (802.11, 802.11p, 802.15, 802.16e, 802.20, 2G/3G/4G cellular systems, national ITS systems) • being developed by ISO TC204/WG16 – Wide Area Communications • CALM M5 = CALM - Microwave 5 GHz • CLAM

  23. CALM • Overall targets • Support continuous communications • Support ITS services and Internet services • Support of next generation applications: • Major push in Vehicle Safety Communication • New commercial applications made possible by high data rate & long range • Support master/slave and peer-peer modes • Support user transparent networking spanning multiple media, media providers and beacons • M5: No harmful cross-interference with regional DSRC standards • M5: Support relevant ASTM / IEEE 802.11 / ETSI Hiperlan modes

  24. CALM • Architecture CME : CALM Management Entity SAP : Service Access Point NME : Network Management Entity

  25. CALM • CALM Network Scenario(1)

  26. CALM • CALM Network Scenario(2)

  27. CALM • Selected CALM media • ISO 21212: 2G Cellular (GSM) • ISO 21213: 3G Cellular (UMTS) • ISO 21214: InfraRed • ISO 21215: M5 (802.11p) • ISO 25112: WiMAX (802.16e) • ISO 25113: HC-SDMA (802.20) • ISO xxxxx: Bluetooth (802.15) • ISO xxxxx: Ethernet (802.3)

  28. CALM • CALM M5 vs. 802.11p (WAVE) • WAVE PHY/MAC is IEEE 802.11p • CALM M5 incorporates WAVE and adds following features : • Global (European) 5 GHz spectrum • Regulatory domain (border) management • Directivity and EMC control • Regional DSRC cooperation • Multiple radios/interfaces/antenna management through network connection • GPRS/UMTS/+++ network interconnectivity

  29. V2V Network Protocols

  30. V2V Network Protocols • Issues of V2V protocols • Mobility • Highly dynamic, hence An on-going session suffers frequent path breaks • Bandwidth Constraint • Use the Bandwidth optimally by keeping the overhead as low as possible • Error-Prone Shared Radio Channel • Find paths with less congestion • Hidden and Exposed Terminal problem Mesh network and MANET routing protocols can solve these issues

  31. V2V Network Protocols • MANET • Mobile Ad-hoc NETwork • IETFWorking Group (1997.7) ※Infrastructure-less communication without static base-station or wired backbone network • < MANET(이동 애드-혹 네트워크) > • < 일반 무선 네트워크 >

  32. V2V Network Protocols • MANET Characteristic • Cannot assume, that every computer is within communication range of every other computer • can connect to Internet by Gateway • every nodes in MANET can be host or router • Dynamic topology • Self-starting • No administrator • Battery constraint, less computing power and mobility => needs another routing protocol different from wired-network < Independent> < connected to Infrastructure>

  33. V2V Network Protocols • Wireless Mesh Network Link Types Node Types Intra-mesh wireless links Stationary client access Mobile client access Internet access links Wireless routers Gateways Printers, servers Mobile clients Stationary clients

  34. GW V2V Network Protocols • Wireless Mesh Network : Gateways • Multiple interfaces (wired & wireless) • Mobility • Stationary (e.g. rooftop) – most common case • Mobile (e.g., airplane, busses/subway) • Serve as (multi-hop) “access points” to user nodes • Relatively few are needed, (can be expensive)

  35. V2V Network Protocols • Wireless Mesh Network : Wireless Routers • At least one wireless interface. • Mobility • Stationary (e.g. rooftop) • Mobile (e.g., airplane, busses/subway). • Provide coverage (acts as a mini-cell-tower). • Do not originate/terminate data flows • Many needed for wide areas, hence, cost can be an issue.

  36. V2V Network Protocols Converges Wireless Mesh network and MANET WirelessNetworking SingleHop Multi-hop Infrastructure-based (hub&spoke) Infrastructure-less (ad-hoc) Infrastructure-based (Hybrid) Infrastructure-less (MANET) 802.11 802.16 802.11 Bluetooth Cellular Networks Car-to-car Networks (VANETs) Wireless Sensor Networks Wireless Mesh Networks

  37. V2V Network Protocols What kind MANET Protocol is good for ITS/Telematics Networking? • V2V and V2I convergence • V2V Communication : MANET routing protocol • V2I Communication : Mesh network IPBackbone TSP Server RSE has a roll like a WMN gateway RSE RSE RSE Vehicles can be a wireless routers Data forwarded by MANET Protocol Data

  38. V2V Network Protocols • MANET Protocols - proactive and reactive routing Algorithms • Proactive(table-driven) • maintains fresh lists of destinations • maintains routes by periodically distributing routing tables • main disadvantages • Respective amount of data for maintenance • Slow reaction on restructuring and failures • Reactive(on-demand) • finds a route on demand by flooding Route Request packets • main disadvantages • High latency time in route finding • Excessive flooding can lead to network clogging

  39. V2V Network Protocols • MANET – Classification of Ad-hoc Routing Protocols

  40. V2V Network Protocols • MANET – DSDV (Table Driven) • Destination-Sequenced Distance Vector • Keep the simplicity of Bellman-Ford • Avoid the looping problem • Tag each routing table entry with a Destination sequence number • Allow fast reaction to topology changes • Make immediate route advertisement on significant changes in routing table • wait with advertising of unstable routes • Remain compatible in cases where a base station is available • Proactive • Each node maintains routing information for all known destinations • Routing information must be updated periodically • Traffic overhead even if there is no change in network topology • Maintains routes which are never used

  41. V2V Network Protocols • MANET – DSDV : Transmitting Route Information • Routing information is transmitted by broadcast • Updates are transmitted periodically or immediately when any significant topology change is available • Rules to set sequence number information • On each advertisement increase own destination sequence number (use only even numbers) • If a node is no more reachable (timeout) increase sequence number of this node by 1 (odd sequence number) and set metric =  • Full dump: all information from the transmitting node • Incremental dump: all information that has changed since the last full dump • Full dump if incremental dump exceeds one NPDU (network protocol data unit)

  42. V2V Network Protocols • MANET – DSDV : Route Selection • Update information is compared to own routing table • Select route with higher destination sequence number • Select the route with better metric when sequence numbers are equal.

  43. V2V Network Protocols • MANET – DSDV : Problem • DSDV requires a full dump update periodically  DSDV is not efficient in route updating • DSDV limits the number of nodes that can join the network • Whenever topology of a network changes, DSDV is unstable until update packets propagate through the network • DSDV is effective for creating ad-hoc networks for small populations of mobile nodes • DSDV is a fairly brute force approach, because connectivity information needs periodical update througout the whole network

  44. V2V Network Protocols • MANET – DSR (On-Demand) • On-demand route discovery • DSDV is a proactive protocol: maintains all topology information • DSR is a reactive protocol : maintains active routes • Routes automatically determined and maintained • No periodic packets => entirely on-demand • E.g. Routing advertisement, Link status sensing, Neighbour detection packets • Source routing • sender of a packet determines the complete sequence of nodes to forward the packet • No need to maintain information at intermediate nodes • reaction to topology changes more rapid => node caches multiple routes to destination • Avoids need to perform Route Discovery each time a route breaks

  45. V2V Network Protocols • MANET – DSR : main functions • Route Discovery: • Allows any host to dynamically discover a route to any other host in the ad hoc network. • A host initiating a route discovery broadcasts a route request packet • Each route request packet contains a route record • If successful, initiating host receives a route reply packet • The route is saved in the cache for future use • Route maintenance: • Host monitors the correct operation of routes in use

  46. V2V Network Protocols • MANET – DSR : Route Discovery • When node S wants to send a packet to node D, but doesn’t know route to D, it initiates a route discovery • Source node S floods Route Request (RREQ) • Each node appends its own address when forwarding RREQ • When node d receives RREQ it sends RREP to node S • Duplicate RREQ are discarded RREQ transmission S A RREP transmission B Broadcast E C F D G

  47. V2V Network Protocols • MANET – DSR : Route Reply (RREP) • Route Reply (RREP) is sent by reversing the route in Route Request (RREQ) • An intermediate node having a route to D can also send back a RREP RREP [S,A,B,C,D] S A RREP transmission B Broadcast E C F D G

  48. V2V Network Protocols • MANET – DSR : Advantages and disadvantages • Advantages • Reactive: routes maintained only between nodes who need to communicate • Route caching can reduce route discovery overhead • Disadvantages • Packet header size grows with route length due to source routing • Flood of route requests may potentially reach all nodes in the network • Care must be taken to avoid collisions between route requests and route reply propagated by neighboring nodes • Route Reply Storm problem • When a node sending RREP hears another RREP with a shorter route • Route reply storms also prevented by randomising delay time before sending route replies

  49. V2V Network Protocols • MANET – AODV (Ad-hoc On-demand Distance Vector) • Designed for MANETs with 10,000 to 100,000 nodes • Improves scalability and performance • Reduces dissemination of control traffic • Eliminates overhead on data traffic • Uses a broadcast route discovery mechanism • Every node maintains two separate counters • Sequence number • Broadcast-id (RREQ ID) • Node sequence number ensures loop freedom • Route’s “freshness” is decided by sequence numbers that each node maintains for all destinations in their routing table • Only active routes are maintained

  50. V2V Network Protocols • MANET – AODV : Route Discovery • Route discovery is initiated by broadcasting RREQ • When sender has no route to destination, or • Route to destination is invalid or expired • RREQ contains last known Dest Seq Num • When anintermediate node receives a RREQ, it records a “reverse” distance vector back towards the source then broadcasts the RREQ to its neighbors • A neighbor satisfies the RREQ sends a RREP back to the source • If an intermediate node is a destination or has a route entry for the destination • The route reply travels in the “reverse path” set up when the request packet was being forwarded

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