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Mesh networks and vehicular support: the UCLA MobiMesh case study

MeshNet Workshop, Santander, June10 2009

Mario Gerla, Eugenio Giordano, Giovanni Pau UCLA, Computer Science Dept

Outline

• Vehicular Ad Hoc Networks (VANETs)– Opportunistic ad hoc networking

• V2V applications• Infrastructure support and Vehicular Mesh• UCLA CAMPUS Testbed and MobiMesh

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Traditional Mobile Ad Hoc Network

• Instantly deployable, re-configurable (no fixed infrastructure)

• Satisfy a “temporary” need• Mobile (eg, PDAs)

– Low energy

• Multi-hopping ( to overcome obstacles, etc.)• Challenges: Ad hoc routing, multicast, TCP, etc

Examples: military, civilian disaster recovery

Vehicular Ad Hoc Network (VANET)

• No fixed infrastructure?– Several “infrastructures”: WiFi, Cellular, WiMAX, Satellite..

• “Temporary” need?– For vehicles, well defined, permanent applications

• Mobile?– YES!!! But not “energy starved”

• Multi-hop routing?– Most of the applications require broadcast or “proximity” routing– Infrastructure offers short cuts to distant destinations– Multihop routing required only in limited situations (eg, Katrina scenario)

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VANET and Infrastructure

• VANET => Opportunistic Ad Hoc Network– Opportunistic in the way it uses the Infrastructure

• Infrastructure opportunistically “bypassed ” with “ad hoc” if too costly or inadequate

• Major difference between MANETs and VANETs is presence and role of INFRASTRUCTURE

VANET New Research Opportunities

• Physical and MAC layers:– Radios (MIMO, multi-channel, cognitive)

– Positioning in GPS deprived areas

• Network Layer & Routing:– Mobility models– Network Coding– Geo routing

– Content based routing– Delay tolerant routing

• Security and privacy• New Applications:

– Content distribution , mobile sensing, safety, etc

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The Enabling Standard: DSRC / IEEE 802.11p

• Car-Car communications at 5.9Ghz

• Derived from 802.11a

• three types of channels: Vehicle-Vehicle service, a Vehicle-Roadside service

and a control broadcast

channel .

• Ad hoc mode; and infrastructure mode

• 802.11p: IEEE Task Group for Car-Car communications

Forward radar

Computing platform

Event data recorder (EDR)

Positioning system

Rear radar

Communication facility

Display

V2V Applications

• Safe Navigation• Efficient Navigation/Commuting (ITS)• Location Relevant Content Distr.• Urban Sensing• Advertising, Commerce, Games• Etc

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V2V Applications

• Safe navigation:

– Forward Collision Warning, – Intersection Collision Warning…….– Advisories to other vehicles about road

perils• “Ice on bridge”, “Congestion ahead”,….

• Traffic light AP’s serve as store and forwarders:– To prevent intersection collisions

V2V communications for Safe Driving

Vehicle type: Cadillac XLRCurb weight: 3,547 lbsSpeed: 65 mphAcceleration: - 5m/sec^2Coefficient of friction: .65Driver Attention: YesEtc.

Vehicle type: Cadillac XLRCurb weight: 3,547 lbsSpeed: 45 mphAcceleration: - 20m/sec^2Coefficient of friction: .65Driver Attention: NoEtc.

Vehicle type: Cadillac XLRCurb weight: 3,547 lbsSpeed: 75 mphAcceleration: + 20m/sec^2Coefficient of friction: .65Driver Attention: YesEtc.

Vehicle type: Cadillac XLRCurb weight: 3,547 lbsSpeed: 75 mphAcceleration: + 10m/sec^2Coefficient of friction: .65Driver Attention: YesEtc.

Alert Status: None

Alert Status: Passing Vehicle on left

Alert Status: Inattentive Driver on Right

Alert Status: None

Alert Status: Slowing vehicle aheadAlert Status: Passing vehicle on left

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V2V Applications (cont)

• Efficient Navigation– GPS Based Navigators

– Dash Express (just came to market in 2008):

– Future: collaboration between Navigator and Transport Dept

Intelligent Transport Systemsintelligent lane reservations

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V2V Applications (cont)

• Content delivery/sharing:– Location related/relevant– Traffic information– Local attractions– Tourist information, etc

CarTorrentCarTorrentCarTorrentCarTorrent : cooperative download of : cooperative download of : cooperative download of : cooperative download of location multimedia fileslocation multimedia fileslocation multimedia fileslocation multimedia files

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You are driving to VegasYou are driving to VegasYou are driving to VegasYou are driving to VegasYou hear of this new show on the radioYou hear of this new show on the radioYou hear of this new show on the radioYou hear of this new show on the radio

Video preview on the web (10MB)Video preview on the web (10MB)Video preview on the web (10MB)Video preview on the web (10MB)

One option: Highway One option: Highway One option: Highway One option: Highway Infostation Infostation Infostation Infostation downloaddownloaddownloaddownload

Internet

file

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Incentive for opportunistic Incentive for opportunistic Incentive for opportunistic Incentive for opportunistic ““““ad hoc ad hoc ad hoc ad hoc networkingnetworkingnetworkingnetworking””””

Problems::::Stopping at gas station for full download is a nuisanceStopping at gas station for full download is a nuisanceStopping at gas station for full download is a nuisanceStopping at gas station for full download is a nuisanceDownloading from GPRS/3G too slow and quite expensiDownloading from GPRS/3G too slow and quite expensiDownloading from GPRS/3G too slow and quite expensiDownloading from GPRS/3G too slow and quite expensiveveveve3G broadcast services (MBMS, 3G broadcast services (MBMS, 3G broadcast services (MBMS, 3G broadcast services (MBMS, MediaFLOMediaFLOMediaFLOMediaFLO) only for TV ) only for TV ) only for TV ) only for TV

Observation:::: many other drivers are interested in download sharingmany other drivers are interested in download sharingmany other drivers are interested in download sharingmany other drivers are interested in download sharing

Solution:::: CoCoCoCo----operative P2P Downloading via Caroperative P2P Downloading via Caroperative P2P Downloading via Caroperative P2P Downloading via Car----Torrent (like Bit Torrent (like Bit Torrent (like Bit Torrent (like Bit Torrent in the Internet)Torrent in the Internet)Torrent in the Internet)Torrent in the Internet)

CarTorrent: Basic Idea

Download a piece

Internet

Transferring Piece of File from Gateway

Outside Range of Gateway

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Co-operative Download: Car Torrent

Vehicle-Vehicle Communication

Internet

Exchanging Pieces of File Later

Simulation Results

• Completion time density

200 nodes

40% popularity

Time (seconds)

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Vehicle as Mobile Sensor Platform

• Environment– Traffic density/congestion monitoring– Urban pollution monitoring– Pavement, visibility conditions

• Civic and Homeland security– Forensic accident or crime site investigations – Terrorist alerts

Vehicle as Mobile Sensor Platform

Sensed data uploaded to Peers or to Infrastructure

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Routing in the Vehicle Grid

• Proactive routing (eg OLSR)– Does not scale to millions of vehicles

• On Demand routing (eg AODV)– Flood search too costly

• Geo-routing– Most scalable (no state needed in routers)– GPS available; local coordinates used in blind areas

(tunnels, parking lots, urban canyons)

– Need Geo Location Service

GLS (Geo Location Service)

• Equivalent to DNS for finding geo addresses• Maps vehicle ID (driver, VIN, license plate, etc) t o

the most recent location• For resilience, distributed DHT implementation (in

the Infrastructure)

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Infrastructure based GLS

OLS: Overlay based Location ServerVehicular ID hashed into overlay proxies (eg PASTRY )Mapping: Vehicular ID <=> location

Georouting through the infrastructure

• IPv6 addressing (xy coordinates in header extension )

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A Case for Vehicle Mesh Network

• Infrastructure access is critical for VANET– Virtually ALL applications require it

• 3G and LTE not adequate– Most applications require customer broadcast, not supported by

3G, LTE

• Existing “open AP’s” not adequate for VANETs:– Slow authentication; security and performance concerns; not DSRC

compliant

• Must deploy NEW, dedicated VANET APs

Vehicle Mesh Network (cont)

• Most access points are in locations with no easy cable/fiber Internet Access– Traffic lights; light poles; highway bridge structures

• Moreover, fast deployment in rapidly changing urban landscape desirable– Wireless connectivity easier to establish (than cable, fiber)

• ENTER => Vehicle Mesh Network

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Traffic Lights and Mesh Network

The Vehicular Mesh Network

• Covers the entire urban area• May include mobile mesh nodes (eg, public busses, p olice

cars, etc)• Most mesh nodes directly connect to Internet Overlay• Channel to vehicles is 802.11.p (aka DSRC, WAVE)• Channel between AP’s can be anything (DSRC, 802.11a ,

WiMAX, 3G or LTE)• Design Challenges: QoS, Security, Reliability, Emergency

mode

– The Vehicle Mesh must be Carrier-Grade!

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Wireless Mesh (red) and Overlay (green)

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Emergency Mode

• Assumption: the infrastructure has completely failed (namely, no power, no 3G, no Internet)– Earthquake, flood (Katrina), terrorist attack

• We need an emergency network to:– Evacuate vehicles safely from the disaster area– To maintain minimal comms between first responders/rescue teams

• Problems:– Internet (and Overlay) has failed– V2V paths in the Grid have too many hops:

• Highly unreliable, Poor QoS, Unstable TCP!

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“Emergency Mesh”

• Some Mesh nodes survive power outage:– Solar powered mesh nodes– Public Vehicles (eg busses) that join the Mesh upon emergency– Both equipped with Cog Radios to extend range

• “Emergency Mesh” provides low bandwidth backbone connectivity across the urban area:– Efficient evacuation of vehicles/people from disaster area– Emergency comms and coordination among rescue teams

• Cog Radio and white spectrum are key in emergency networking:– Without Cog Radios, VANET will be disconnected– DTN mode unacceptable for real time emergency messages– If connected, the VANET will still suffer from high delays due to

large number of car to car hops on urban paths

V-Mesh with emergency links (green)

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CC--VVeeTTCampus Campus -- Vehicular Vehicular TestbedTestbed

E. Giordano, A. Ghosh,G. Marfia, S. Ho, J.S. Park, PhD

System Design: Giovanni Pau, PhD Advisor: Mario Gerla, PhD

The Plan

• We plan to install our node equipment in:– 30 Campus operated vehicles (including shuttles and facility

management trucks).• Exploit “on a schedule” and “random” campus fleet mobility patterns

– 30 Commuting Vans: Measure urban pollution, traffic congestion etc– 12 Private Vehicles: controlled motion experiments– Cross campus connectivity using 10 node Mesh (Poli Milano).

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C-VeT Goals

Provide:

• A shared virtualized environment to test new protoc ols and applications• Full Virtualization

– MadWiFi Virtualization (with on demand exclusive use)– Multiple OS support (Linux, Windows).

Allow:• Collection of mobility traces and network statistic s• Provide a platform for Urban Sensing, Geo routing e tc• Deployment of innovative V2V/V2I applications• Mesh network testing in operational, emergency and transition mode

MobiMesh

• Wireless:– Mesh to Car: 802.11b/g with Patch

antennas– Mesh inter-connections: 802.11a with high

gain directional antennas

• O/S:– Open WRT OS– MadWiFi support for full configurability

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MobiMesh

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Past Experiments

• Equipment:– 6 Cars roaming the UCLA Campus– 802.11g radios– Routing protocol: OLSR– 1 EVDO interface in the Lead Car – 1 Remote Monitor connected to the Lead Car

through EVDO and Internet• Experiments:

– Connectivity map computed by OLSR– Azureus P2P application– Video/Audio V2V and V2I experiments

Campus Demo: connectivity via OLSR

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Future Testbed/Mesh research

• We plan to use the testbed to validate – Realistic assessment of radio, mobility characteristics– Account for user behavior– Interaction with (and support of ) the Infrastructure– Mesh Network performance; Emergency mode – Scalability to thousands of vehicles using hybrid simulation

• We are looking for collaboration in two areas:– Joint experiments in the C-VeT testbed – Mesh design that meets QoS, Security, Reliability requirements in

operational and emergency modes

Thank You!