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 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
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
Introduction V2V Communication : Vehicle Multi-hop Networking V2I Communication : Bi-directional Packet Communication TSP Server Cellular/WiBro Base-station RSE IP Backbone RSE V2I GPS Emergence Message V2V Probe Data Real time Traffic Information Warning Message Warning Message Accident Occur
Introduction (Examples-1) WISDOM(V2I) Information - Data Collection - Information Provision - Provide information to traffic information center Management - Traffic signal control (Optimization for bus, emergency car) - Driving speed control Safety - Accident Avoidance
Introduction (Examples-2) VII(Vehicle Infrastructure Integration ) Traffic signal violation warning Public safety vehicle priority signal activation Provide traffic information
DSRC
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)
DSRC Technical Characteristics 5.850 to 5.925 GHz Bandwidth = 75 MHz Shared, but Transportation is primary
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
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
WAVE (IEEE 802.11p)
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)
WAVE consists of four standards: IEEE P1609.1 - Resource Manager - specifies the services and interfaces of the WAVE Resource Manager application ه ه ه 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
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)
WAVE WAVE : Scope
WAVE Protocol Stack MLME : MAC Layer Management Entity PLME : Physical Layer Management Entity WME : WAVE Management Entity WSMP : WAVE Short Message Protocol
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 manage ment 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
CALM (Continuous Air interface for Long and Medium range)
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 CLAM 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
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
CALM Architecture CME : CALM Management Entity SAP : Service Access Point NME : Network Management Entity
CALM CALM Network Scenario(1)
CALM CALM Network Scenario(2)
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)
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
V2V Network Protocols
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
MANET V2V Network Protocols Mobile Ad-hoc NETwork IETF Working Group (1997.7) Infrastructure-less communication without static base-station or wired backbone network Backbone Network < MANET( 이동애드-혹네트워크 < ) > 일반무선네트워크 >
V2V Network Protocols MANET Characteristic Cannot assume, that every computer is within communication range of every other computer Gateway Infrastructure Network < Independent > < connected to Infrastructure> 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
V2V Network Protocols Wireless Mesh Network Node Types Wireless routers Gateways Link Types Intra-mesh wireless links Stationary client access Printers, servers Mobile client access Mobile clients Stationary clients Internet access links
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) GW
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.
V2V Network Protocols Wireless Networking Converges Wireless Mesh network and MANET Single Hop 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 Wireless Sensor Networks Wireless Mesh Networks Car-to-car Networks (VANETs)
V2V Network Protocols V2V and V2I convergence V2V Communication : MANET routing protocol V2I Communication : Mesh network What kind MANET Protocol is good for ITS/Telematics Networking? TSP Server RSE IP Backbone RSE RSE RSE has a roll like a WMN gateway Data Vehicles can be a wireless routers Data forwarded by MANET Protocol
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 ه ه 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 ه ه High latency time in route finding Excessive flooding can lead to network clogging
V2V Network Protocols MANET Classification of Ad-hoc Routing Protocols
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
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)
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.
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
V2V Network Protocols MANET DSR (On-Demand) On-demand route discovery - DSDV is a proactive protocol: maintains all topology i nformation - 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 sequenc e of nodes to forward the packet ه No need to maintain information at intermediate nodes - reaction to topology changes more rapid => node caches multiple routes to destination ه Avoids need to perform Route Discovery each time a route breaks
V2V Network Protocols MANET DSR : main functions Route Discovery: - Allows any host to dynamically discover a route to any othe r host in the ad hoc network. - A host initiating a route discovery broadcasts a route reque st packet - Each route request packet contains a route record - If successful, initiating host receives a route reply packet ه The route is saved in the cache for future use Route maintenance: - Host monitors the correct operation of routes in use
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 S Broadcast E A F B G C RREQ transmission RREP transmission D Duplicate RREQ are discarded
V2V Network Protocols MANET DSR : Route Reply (RREP) RREP [S,A,B,C,D] S A RREP transmission Broadcast E F B G C D 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
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 ه ه 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
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
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 an intermediate 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
V2V Network Protocols MANET AODV : Route Table Route Table Entry Destination IP Address Destination Seq. Num Valid Destination Seq. Num field State and routing flags Network Interface Hop Count (# of hops to destination) Next Hop List of Precursors Lifetime Route updated whenever node receives new information about the seq. num from RREQ, RREP or RERR route only updated if the dest seq num is either > dest. seq num in route table seq nums are equal, but the new hop count + 1 < existing hop count in the routing table Dest seq num is unknown. Lifetime = ACTIVE_ROUTE_TIMEOUT
V2V Network Protocols Routing protocol Analysis for vehicle Ad-Hoc requires protocol that can find path more faster for High-mobility Ad hoc Among nowadays routing protocols, on-demand method has more efficiency but require new routing protocol adopted on V2V environment
Projects and Standards
Projects and Standards
Projects and Standards Services & Project (Korea) WISDOM - WISDOM - Wireless Interface Signal control system for Dynamic and Optimal Management - Real time signal control - provide information and safety Black-Box based emergency service - e-call - ACN service U-Traffic related service UTIS (Urban Traffic Information System)
Projects and Standards Standards (Korea) DSRC - TTA ه WAVE - ETRI ه ه - TTA ه CALM ASK -> QPSK Planed to make a convergence among cellular and DMB, wireless lan, Advanced Short Range Communication (ADSRC) Planed to make international standard to provide high speed packet service for 5.8GHz ~10MHz can support handover Researching Broadband wireless LAN standards for 전파방송기술위원회 (TC3) PG310 - ITS/Telematics - National Police headquarters - UTIS ه Wireless communication system for ITS ه Based on CALM ه ه Mobility : 180Km/h (max) Collect/provide Real time traffic information
Projects and Standards C2C-C Consortium Industrial consortium (mostly) comprised of car manufacturers and electronics suppliers operating in Europe Primary goal: Defining a European standard for vehicular communication Aims at harmonizing with other bodies (e.g. ISO) to build an European infrastructure for ITS applications
Projects and Standards Unit Architecture and C2C-CC WGs