Cooperation in Autonomous Vehicular Networks

Sidi Mohammed Senouci, Abderrahim Benslimane, Hassnaa Moustafa

WILEY Publisher

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Outline

• Introduction

• Overview on Vehiculer Networks

• Cooperation at Different OSI Layers– Cooperation at Lower Layers– Cooperation at Network Layer– Security and Authentication versus Cooperation– Cooperation at Upper Layers

• Conclusion

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Introduction (1/2)

• Vehicular networks are considered as a novel class of wireless networks

– Also known as VANETs (Vehicular Ad hoc Networks)– One of the ad hoc networks real-life applications– Enabling communications among nearby vehicles as well as between vehicles

and nearby fixed equipments, usually described as roadside equipments

• Vehicular networks applications – Road safety applications oriented to the vehicle or to the driver– Entertainment and commercial applications for passengers, making use of a

plethora of cooperating technologies

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Introduction (2/2)

• The increased number of vehicles on the road increases significantly the unpredictable events outside vehicles

– Accidents arrive rarely from vehicles themselves and mainly originate from on-road dynamics

– Cooperation using vehicular networks must be introduced into transportation networks to improve overall safety and network efficiency, and to reduce the environmental impact of road transport

• Two different ways to achieve cooperative collision warning: – Passive approach: a vehicle broadcasts frequently its location, speed, direction,

etc, and it is the responsibility of the receipt vehicle to take the decision on the eminent danger if it judges its existence

– Active approach: a vehicle causing an abnormal situation broadcasts an alarm message containing its location in order to warn vehicles in its neighborhood

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Overview on Vehicular Networks (1/2)

• Vehicular networks can be deployed by – Network operators, – Service providers,– Through integration between operators, providers and a governmental authority

• Deployment environments– Highways,– Urban (City) environments,– Rural environments

• Deployment architectures– Pure wireless Vehicle-to-Vehicle ad hoc network (V2V) – An Infrastructure-to-Vehicle or Vehicle-to-Infrastructure (I2V, V2I) architecture with

wired backbone and wireless last hops– A hybrid architecture that does not rely on a fixed infrastructure in a constant manner,

but can exploit it for improved performance and service access when it is available

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• Technical Challenges – Potentially large scale– High mobility– Network partitioning– Network topology and connectivity– Security– Applications distribution

• Several technical challenges are not yet resolved in vehicular networks

– Research works and contributions are needed to investigate such challenges aiming to resolve them

Overview on Vehicular Networks (2/2)

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Cooperation at Different OSI Layers (1/12)

Cooperation at Lower Layers• MAC layer cooperation

– Homogenous MAC cooperation, where one distinct MAC layer is present in the system

– Heterogeneous MAC, where MAC protocols from different systems are used for cooperation

• There is a need for efficient MAC protocols– Adapting to the high dynamic environment of vehicular networks– Considering messages priority of some applications (ex, accidents warnings)– Allowing for fast association and low communication latency between

communicating vehicles

• MAC layer cooperation allows for – Service’s reliability for safety-related applications– Time-sensitivity consideration during messages’ transfer– Quality and continuity of services consideration for non-safety applications 7

Cooperation at Different OSI Layers (2/12)

Cooperation at Lower Layers – cntd

• Many MAC protocols for vehicular ad hoc networks have been introduced in the literature.

– No involvement of any cooperation between vehicles except if we consider the competition to access a given channel (as in IEEE 802.11p or DSRC) is a kind of cooperation which is not realistic.

• Cooperative collision avoidance system is proposed following two approaches:

– Cluster-based approach: based upon several criteria, which define the movement of the vehicles, namely the directional bearing and relative velocity of each vehicle, and also the inter-vehicular distance

– Cooperative risk-aware Media Access Control (MAC) protocol: increasing the responsiveness of the proposed CCA scheme. According to the order of each vehicle in its corresponding cluster, an emergency level is associated with the vehicle that signifies the risk to encounter a potential emergency scenario

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Cooperation at Different OSI Layers (3/12)

Cooperation at Network Layer • Concerns the cooperation mechanisms between network elements

for traffic forwarding

• Needs efficient routing protocol that enables effective network resource management

• Nodes behavior consideration– A malicious or self-interested user can misbehave and does not cooperate. A

malicious user could inject false routing messages into the network in order to break the cooperative paradigm

– The basic vehicular network functions subject to selfishness are dissemination and routing

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Cooperation at Different OSI Layers (4/12)

Cooperation at Network Layer – cntd

• Cooperative Routing in Vehicular Networks• GyTAR (improved Greedy Traffic Aware Routing protocol): A

geographical routing protocol for vehicular networks capable to find robust routes within city environments. The protocol is based on the cooperation between vehicles at network layer

• GyTAR has three components: – Completely decentralized scheme for the estimation of the vehicular

traffic density in city-roads (IFTIS)

– Dynamic selection of the junctions through which a packet must pass to reach its destination

– Improved greedy forwarding mechanism between two junctions

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Cooperation at Different OSI Layers (5/12)

Cooperation at Network Layer – cntd

• Cooperative Dissemination in Vehicular Networks within City Environment

• GVI (geo-localized virtual infrastructure): a mechanism based on the cooperation between vehicles in order to elect vehicles that will perpetuate information broadcasting within an intersection area

• GVI is composed of two phases: – selecting vehicles able to reach the broadcast area

– only one among the selected vehicles is elected as the local broadcaster. It will perform a local / single hop broadcast once it reaches the broadcast area

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Cooperation at Different OSI Layers (6/12)

Cooperation at Network Layer – cntd• Cooperative Dissemination in Vehicular Networks within a Highway• ODAM (Optimized Dissemination of Alarm Messages):

• To face the network fragmentation while avoiding neighbors computation

• Geocast messages to relevant ares in the road• Introduce Defer Time Distance

- reduce the number of message collisions- reduce the number of retransmission - best use of bandwidth- reduce the delay

• Use dynamical Relays to face the fragmentation • Tack into account the direction of circulation

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Cooperation at Different OSI Layers (7/12)

Cooperation at Network Layer – cntd• ODAM (Optimized Dissemination of Alarm Messages):

Alarm message propagation

Risk zone

Accident

x

ab

c

Transmission range

R

DRtimedeferxdefertime sx )(

_max_)(

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Cooperation at Different OSI Layers (7/12)

Cooperation at Network Layer – cntd

• Self-Organizing Cooperative Vehicular Networks• Self-organization can be defined as the emergence of system-wide

adaptive structure and functionality from simple local interactions between individual entities

• CSP (Cluster-based Self-organizing Protocol): a vehicular network self-organizing architecture based on geographical clustering to ensure a permanent self-organization of the whole network

– Key idea: » Divide each road stump in segments seen as fixed clusters » Elect a cluster head for each segment to act as backbone

member– CSP improves the connectivity without producing a great overhead

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Cooperation at Different OSI Layers (8/12)

Security and Authentication versus Cooperation• Cooperation in vehicular networks could penalize the service

access and the whole communication – Malicious nodes could be involved in the communication

• Secure and reliable cooperation is needed– Assuring that only authorized users are granted network’s access

• Attacks in vehicular networks impacting cooperation– External attacks, where the attackers do not participate in the network, however they

could carry out some attacks and malicious acts impacting the communication and the network and services performance,

– Internal attacks, where the attackers participate in the network and have legitimate service access, however they penalize the network performance through malicious and non cooperative acts

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Cooperation at Different OSI Layers (9/12)

Security and Authentication versus Cooperation - cntd

• Counter-measures against different attacks impacting cooperation– Authentication and access control, allowing only authorized users to

have connectivity– Fails to prevent against internal attacks

• Internal attackers are nodes that are authenticated and authorized to participate in the network; however, they can be harmful nodes causing network and service performance degradation

– Non cooperative behaviors (selfishness, greediness, and Denial-of-Services or DoS)– A need for complementary mechanisms to authentication and access control

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Cooperation at Different OSI Layers (10/12)

Security and Authentication versus Cooperation – cntd• Prevention against external attacks

• Authentication and access control– Shared key (weak solution)

– IEEE 802.11i approach

– Multi-hop 802.11i

– Kerberos model adapted to the multi-hop environment

– PANA (a Protocol for carrying Authentication and Network Access )

• Prevention against internal attacks• Complementary mechanisms to authentication and access control.

– Watchdog: based on monitoring neighbors to identify a misbehaving node that does not cooperate during data transmission

– CONFIDANT and Catch: incorporate an additional punishment mechanism making misbehavior unattractive through isolating misbehaving nodes

– Domino: solves the greedy sender problem in 802.11 WLANs with a possible extension to multihop wireless networks and hence vehicular networks

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Cooperation at Different OSI Layers (11/12)

Cooperation at Upper Layers• Several cooperative applications are based on cooperation between

vehicles and the infrastructure belonging to the government, or private network operators or service providers– CURB - Cooperative Urban Applications: aims to improve the efficient use of the

urban road network at both local junction and network level, and enhance individual mobility.

– CINT - Cooperative Inter-urban Applications: aims to enable cooperation and communication between the vehicle and the infrastructure on inter-urban highways.

– CF&F - Cooperative Freight & Fleet: aims to increase the safety of dangerous goods transport and optimize transport companies' delivery logistics.

– Cooperative Monitoring - COMO block: placed as a central basic service to cooperate closely with CURB, CINT and CF&F applications to capture their particular requirements about monitoring of traffic and environmental information.

– Infrastructure-Free Traffic Information System - IFTIS: aims at road density estimation through being based on a distributed exchange and maintenance of traffic information between cooperating vehicles traversing the routes.

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Cooperation at Different OSI Layers (12/12)

Cooperation at Upper Layers – cntd• Traffic Density Estimation

– IFTS (Infrastructure-Free Traffic Information System): A decentralized and infrastructure-free mechanism for the estimation of vehicular traffic density in city-roads

– The approach is based on the distributed exchange and maintenance of traffic information between cooperative vehicles traversing the routes

• Smart Parking– Collect information about parking space availability and coordinate drivers

in order to guide them to free parking spots. – At every parking spot a wireless mote is deployed which tracks the

occupancy and cooperates with other nearby motes and vehicles. – Each vehicle is equipped with a wireless communication device that

provides a driver with information about parking space availability and guides them eventually by turn-by-turn instructions

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Conclusion (1/2)

• Vehicular networks have been emerged as a new type of autonomous networks allowing for vehicle-to-infrastructure and vehicle-to-vehicle communication

• Applications in vehicular networks range from road safety applications oriented to the vehicle or to the driver, to entertainment and commercial applications for passengers

• The increased number of vehicles on the road increases significantly the unpredictable events outside vehicles

– Cooperation using vehicular networks must be introduced into transportation networks to improve overall safety and network efficiency

– Cooperation is crucial in entertainment applications to allow reliable services’ access through the multihop communication during vehicles’ mobility

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Conclusion (2/2)

• Cooperative techniques will likely survive in scenarios which are independent of users (no selfishness) but rather depending on machines or operator-programmed decision engines.

• This chapter explores cooperation issues in autonomous vehicular networks at different levels

– High-level services: should be build following a cooperative model that depends exclusively on the participation of contributing vehicles and the existing infrastructure

– Vehicular networks scenarios relying on an infrastructure (that could be eventually limited infrastructure) could satisfy cooperation through resolving several technological issues

• Such scenarios are promising for real deployment of vehicular networks in a public context of generalized mobility

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