V2V and V2I Communication
건국대학교
MBC Lab
Contents
Projects and Standards
V2V Network Protocols
CALM
WAVE
DSRC
V2I/V2V Communication Introduction
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
V2V Communication : Vehicle Multi-hop Networking
V2I Communication : Bi-directional Packet Communication
Introduction
Accident Occur
Emergence
Message
Warning
Message
Cellular/WiBro
Base-station
Probe
Data
TSP Server
RSE
Real time
Traffic
Information
V2V
Warning
Message
IP Backbone
RSEV2I GPS
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 defines data flows and resources
ه defines command message formats and data storage formats
ه 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 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
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 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
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
ArchitectureCME : 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
V2V Network Protocols
MANET
►Mobile Ad-hoc NETwork
►IETF Working Group (1997.7)
※Infrastructure-less communication without static base-station or wired backbone network
Backbone Network
< MANET(이동 애드-혹 네트워크) >< 일반 무선 네트워크 >
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
Infrastructure
NetworkGateway
< Independent > < connected to Infrastructure>
V2V Network Protocols
Wireless Mesh Network
Wireless routers
Gateways
Printers, servers
Mobile clients
Stationary clients
Intra-mesh wireless links
Stationary client access
Mobile client access
Internet access links
Node Types Link Types
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
Multi-hop
Infrastructure-less
(ad-hoc)
Infrastructure-based
(Hybrid)
Infrastructure-less
(MANET)
Single
Hop
Cellular
NetworksWireless Sensor
Networks
Wireless Mesh
Networks
Car-to-car
Networks
(VANETs)
Infrastructure-based
(hub&spoke)
802.11 802.16 Bluetooth802.11
Converges Wireless Mesh
network and MANET
V2V and V2I convergence ► V2V Communication : MANET routing protocol
► V2I Communication : Mesh network
V2V Network Protocols
Data
TSP Server
RSE
IP Backbone
RSERSE
Data forwarded by
MANET Protocol
Vehicles can be a
wireless routers
RSE has a roll
like a WMN
gateway
What kind MANET
Protocol is good for
ITS/Telematics
Networking?
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 Respective amount of data for maintenance
ه Slow reaction on restructuring and failures
►Reactive(on-demand)- finds a route on demand by flooding Route Request
packets
- main disadvantages
ه High latency time in route finding
ه 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 packetه 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 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
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
► Duplicate RREQ are discarded
S A
B
C
D
E
F
G
RREQ transmission
Broadcast
RREP transmission
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
S A
B
C
D
E
F
G
Broadcast
RREP transmission
RREP [S,A,B,C,D]
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 problemه When a node sending RREP hears another RREP with a
shorter route
ه 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 seqnum 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 routingprotocols, 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 ASK -> QPSK
► WAVE- ETRI
ه Planed to make a convergence among cellular and DMB, wireless lan, Advanced Short Range Communication (ADSRC)
ه Planed to make international standard to provide high speed packet service for 5.8㎓~10㎒ can support handover
- TTA
ه Researching Broadband wireless LAN standards for 전파방송 기술위원회 (TC3) PG310 - ITS/Telematics
► CALM- National Police headquarters - UTIS
ه Wireless communication system for ITS
ه Based on CALM
ه Mobility : 180Km/h (max)
ه 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