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 Introduction1
비넷에 과한 강의를 시작하겠습니다.

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 V2I V2V V2V Communication : Vehicle Multi-hop Networking
V2I Communication : Bi-directional Packet Communication
RSE : Road Side Equipment
TSP : Telematics Service Provider
Cellular/WiBro Base-station
TSP Server
IP Backbone
V2I
GPS
RSE
RSE
V2V
Emergence Message
Warning Message
Warning Message
Probe Data
Real time
Traffic
Information
TSP 서버는 Traffic info 와 map info contents User info등을 제공
GPS를 통해 위치 정보를 파악하여 사고 시 차고 차량이 사고 위치를 주변 노드(자동차) 들에게 Propergation 함
텔레매틱스 터미널 즉, 자동차는 위치정보를 TSP 서버로 전송하여 위치에 기반한 맞춤형 서비스를 제공받을 수 있다.
그러므로 양방향 서비스는 필수.
Accident Occur

7. 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

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 : Application manager
IEEE : Network service
IEEE : Medium Access Control
IEEE 1556 : Security

14. WAVE (IEEE p) 1
비넷에 과한 강의를 시작하겠습니다.

15. WAVE
What is WAVE?
IEEE 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 P Security Services for Applications and Management Messages
defines secure message formats and processing
IEEE P Networking Services
defines network and transport layer services
defines Wave Short Messages
IEEE P Multi-Channel Operations
provides enhancements to the IEEE 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 ( 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 WAVE Standard
Draft P802.11p: Wireless Access in Vehicular Environments (WAVE)
Defines the lower layers (PHY and MAC) communications stack
IEEE Std ™-2007: Trial-Use Standard for WAVE - Multi-Channel Operation
Provides frequency band coordination and manage ment within the MAC layer
IEEE Std ™-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, p, , e, , 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 / ETSI Hiperlan modes

24. CALM Architecture CME : CALM Management Entity
SAP : Service Access Point
NME : Network Management Entity
간략한 CALM의 구조

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
IETF Working Group (1997.7)
※Infrastructure-less communication without static base-station or wired backbone network
마넷은 Mobile Ad-hoc Network의 약자로
이동 애드혹 네트워크에서 라우팅 기법을 연구하기 위해 IETF에서 1997년에 결성된 워킹그룹 이름이다.
애드-혹 네트워크는 인프라스트럭쳐 없이
노드들간 동적으로 토폴로지가 구성되어 동적인 데이터 전송을 수행한다.
이러한 노드들로 구성된 망을 MANET라고 한다.
< 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>
MANET의 노드들은
독립적은 망으로 존재할 수도 있으며, 인터넷 망에 연결되어 있을 수도 있다.
여기서 중요한 점은 ad-hoc에서는 모든 노드가 서로간의 통신거리내에 없다고 해도
통신을 수행할 수 있다는 것이다.
이를 위해 모든 노드들은 호스트로서의 기능과 라우터의 기능을
동시에 수행하는 것이 MANET 노드들의 특징이다.
라우터의 기능을 수행하는 노드들의 빈번한 참가와 탈퇴가 발생하여
잦은 토폴로지의 변화를 가져와 예측이 힘듬.
노드들은 제한된 전력과 프로세싱 능력, 메모리 자원과 이동성에 관련해서
유선망과는 다른 라우팅 프로토콜이 요구됨

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

34. Wireless Mesh Network : Gateways
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

35. Wireless Mesh Network : Wireless Routers
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. Converges Wireless Mesh network and MANET
V2V Network Protocols
Converges Wireless Mesh network and MANET
Wireless Networking
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
Car-to-car
Networks
(VANETs)
Wireless Sensor
Networks
Wireless Mesh
Networks

37. V2V Network Protocols IP Backbone
What kind MANET Protocol is good for ITS/Telematics Networking?
V2V and V2I convergence
V2V Communication : MANET routing protocol
V2I Communication : Mesh network
IP Backbone
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
High latency time in route finding
Excessive flooding can lead to network clogging
MANET의 라우팅 프로토콜은
proactive와 reactive 방식으로 나눌 수 있으며
proactive는 table-driven, reactive는 on-demand 방식이라고 한다.
프로엑티브 방식
항상 최신의 루트 정보를 유지
주기적으로 또는 토폴로지 변화가 있을 때 네트워크 전체로 라우팅 정보를 전파
모든 이동 노드가 최신 토폴로지 정보를 유지
이러한 방식은 노드로 하여금 지연 없이 최적의 루트로 패킷을 라우팅할 수 있게 한다.
토폴로지의 변화가 심한 경우 토폴로지 정보를 전파하는 과정에서
오버헤드가 과도하게 증가하게 되는 단점이 있습니다.
리엑티브 방식은
패킷을 전달하는 시점에 루트의 탐색 수행
라우팅 프로토콜 메시지의 오버헤드는 적지만
전달하는 순간에 루트 탐색을 시작하므로 일정 시간의 탐색을 위한 지연이 발생
트래픽에 대한 전송 지연을 가져옴

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 S A B E C F D G
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
RREQ transmission A
RREP transmission B
Broadcast E C F D G

47. V2V Network Protocols RREP [S,A,B,C,D]
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
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 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

51. V2V Network Protocols MANET – AODV : Route Table
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
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

52. 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

53. Projects and Standards1
비넷에 과한 강의를 시작하겠습니다.

54. Projects and Standards

55. 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)

56. Projects and Standards
Standards (Korea)
DSRC
TTA
ASK -> QPSK
WAVE
ETRI
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 5.8㎓~10㎒ can support handover
Researching Broadband wireless LAN standards for 전파방송 기술위원회 (TC3) PG310 - ITS/Telematics
CALM
National Police headquarters - UTIS
Wireless communication system for ITS
Based on CALM
Mobility : 180Km/h (max)
Collect/provide Real time traffic information

57. 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

58. Projects and Standards
Unit Architecture and C2C-CC WGs