Vehicular Urban Sensing: Dissemination and Vehicular Urban Sensing: Dissemination and Retrieval UC Irvine, May 21, 2009 Mario Gerla Computer Science Dept, UCLA www.cs.ucla.edu/NRL
Outline • Vehicular Ad Hoc Networks (VANETs) – Opportunistic ad hoc networking Opportunistic ad hoc networking • V2V applications – Content distribution – Urban sensing • Mobeyes (UCLA) – Bio inspired “harvesting” – Security implications • The UCLA CAMPUS Testbed
Traditional Mobile Ad Hoc Network • Instantly deployable, re-configurable (no fixed infrastructure) ast uctu e) • Satisfy a “temporary” need • Mobile (eg, PDAs) – Low energy • Multi-hopping ( to overcome obstacles, etc.) • Challenges: Ad hoc routing multicast TCP etc • Challenges: Ad hoc routing, multicast, TCP, etc Examples: military, civilian disaster recovery Examples: military, civilian disaster recovery
Vehicular Ad Hoc Network (VANET) • No fixed infrastructure? – Several “infrastructures”: WiFi, Cellular, WiMAX, Satellite.. • “Temporary” need? 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) Multihop routing required only in limited situations (eg, Katrina scenario) • VANET => Opportunistic Ad Hoc Network pp – Access to Internet readily available, but.. – opportunistically “bypass it” with “ad hoc” if too costly or inadequate
VANET New Research Opportunities • Physical and MAC layers: – Radios (MIMO, multi-channel, cognitive) 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 Secu ty a d p acy • New Applications: – Content distribution , mobile sensing, safety, etc
The Enabling Standard: DSRC / IEEE 802.11p • Car-Car communications at 5.9Ghz Event data recorder (EDR) Positioning system • Derived from 802.11a Forward radar • three types of channels: Communication facility Vehicle-Vehicle service , Vehicle Vehicle service , a Vehicle-Roadside service and a control Rear radar Display Computing platform broadcast channel . broadcast channel . • Ad hoc mode; and infrastructure mode • 802 11 802.11p: IEEE Task Group for IEEE T k G f Car-Car communications
V2V Applications • Safe Navigation • Efficient Navigation/Commuting (ITS) • Location Relevant Content Distr. Location Relevant Content Distr. • Urban Sensing • Advertising, Commerce, Games Ad ti i C G • Etc
V2V Applications • Safe navigation: – Forward Collision Warning, – Intersection Collision Warning……. I t ti C lli i W i – Advisories to other vehicles about road perils perils • “Ice on bridge”, “Congestion ahead”,….
Car to Car communications for Safe Driving Vehicle type: Cadillac XLR Curb weight: 3,547 lbs Speed: 65 mph Vehicle type: Cadillac XLR Vehicle type: Cadillac XLR Acceleration: - 5m/sec^2 Acceleration 5m/sec^2 Curb weight: 3,547 lbs Coefficient of friction: .65 Speed: 75 mph Driver Attention: Yes Acceleration: + 20m/sec^2 Etc. Coefficient of friction: .65 Alert Status: None Driver Attention: Yes e tte t o es Etc. Alert Status: None Alert Status: Inattentive Driver on Right Alert Status: Slowing vehicle ahead Alert Status: Passing vehicle on left Vehicle type: Cadillac XLR Curb weight: 3,547 lbs Speed: 45 mph Vehicle type: Cadillac XLR Acceleration: - 20m/sec^2 Curb weight: 3,547 lbs Coefficient of friction: .65 Speed: 75 mph S d 75 h Driver Attention: No Alert Status: Passing Vehicle on left Acceleration: + 10m/sec^2 Etc. Coefficient of friction: .65 Driver Attention: Yes Etc.
V2V Applications (cont) • Efficient Navigation – GPS Based Navigators – Dash Express (just came to market in 2008):
Intelligent Transport Systems intelligent lane reservations g QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture.
V2V Applications (cont) • Environment sensing/monitoring: – Traffic monitoring – Pollution probing p g – Pavement conditions (eg, potholes) – Urban surveillance (eg, disturbance) Urban surveillance (eg, disturbance) – Witnessing of accidents/crimes
V2V Applications (cont) • Location related content delivery/sharing: – Traffic information – Local attractions – Tourist information, etc
V2V Applications (cont) Advertising (Ad Torrent): • Access Points push Ads to passing cars A P i t h Ad t i • Advertisement: multimedia file (data, image, video) video) • Movie trailer; restaurant ad; club; local merchant.. Commerce (Flea Net): • virtual market (bazaar) concept in VANET • A mix of mobile and stationary users buy/sell goods using the vehicular network
CarTorrent : CarTorrent : cooperative download of cooperative download of l l locat ocation i i on mu multime l i medi di dia a fil fil files es
You are driving to Vegas You are driving to Vegas You hear of this new show on the radio You hear of this new show on the radio Video Video preview Video Video preview preview on review on on the on the the web the web web (10MB) eb (10MB) (10MB) (10MB)
One option: Highway Infostation download One option: Highway Infostation download Internet file
Incentive for Incentive for opportunistic “ad hoc opportunistic “ad hoc networkin networking” g Problems: Stoppin Stopping at gas at gas statio station for n for full download is full download is a a nuisance nuisance Downloading Downloading from Do Downloading loading from from GPRS/3G rom GPRS/3G GPRS/3G too PRS/3G too too slow too slow slow and slow and and quite and quite quite uite expensi expensive 3G broadca 3G broadcast services (MBMS, MediaFLO t services (MBMS, MediaFLO) on only for ly for TV TV Observation: many other drivers are intereste many other drivers are interested in downl in download ad shari sharing g (l (like in the Interne e in the Internet) Solution: Co-operative P2P Co-operative P2P Downloading Downloading via via Car-Torrent Car-Torrent
Transferring Piece of File from Gateway Outside Range of Gateway CarTorrent: Basic Idea Download a piece Internet
Vehicle-Vehicle Communication Exchanging Pieces of File Later Co-operative Download: Car Torrent Internet
Car Torrent inspired by BitTorrent: I t Internet P2P file downloading t P2P fil d l di Uploader/downloader Uploader/downloader p Uploader/downloader p / Tracker Uploader/downloader Uploader/downloader
Selection Strategy Critical
CarTorrent with Network Coding • Limitations of Car Torrent – Piece selection critical Piece selection critical – Frequent failures due to loss, path breaks • New Approach – network coding pp g – “Mix and encode” the packet contents at intermediate nodes – Random mixing (with arbitrary weights) will do Random mixing (with arbitrary weights) will do the job!
Network Coding e = [ e 1 e 2 e 3 e 4 ] encoding vector tells how packet was mixed (e.g. coded packet p = i d ( d d k t ∑ e i x i where x i is original packet) buffer Receiver recovers original random by mixing matrix Intermediate nodes inversion
CodeTorrent Single-hop pulling (instead of CarTorrent multihop) • Buffer Internet Buffer Buffer e: k blocks B1 * a 1 B2 * a 2 Re-Encoding: Random Linear Comb. * a 3 B3 + Outside Range of AP of Encoded Blocks in the Buffer “coded” block * a k Fil B k Exchange Re-Encoded Blocks Random Linear Com bination Downloading Coded Blocks from AP Meeting Other Vehicles with Coded Blocks Meeting Other Vehicles with Coded Blocks
40% popularity 200 nodes Simulation Results Time (seconds) Completion time density •
Simulation Results • Impact of mobility – Speed helps disseminate from AP and among vehicles Speed helps disseminate from AP and among vehicles – Speed hurts multihop routing ( CarTorrent ) – Car density+multihop promotes congestion ( CarTorrent ) 500 450 shing (s) 10 m/s 400 ownload finis load Time 20 m/s 20 / me (seconds) 350 30 m/s 300 250 40% popularity 200 tim Avg. do Avg. Downl 150 100 50 0 0 A N=100 N=150 N=200 N=100 N=150 N=200 CarTorrent CodeTorrent
Vehicular Sensor Network
Vehicular Sensor Applications • Environment – Traffic density/congestion monitoring Traffic density/congestion monitoring – Urban pollution monitoring – Pavement, visibility conditions y • Civic and Homeland security – Forensic accident or crime site investigations – Terrorist alerts T i t l t
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