wireless networks for cars.ppt - citris and the banatao...
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Wireless Networks for Cars
CITRIS Research Exchange
Raja Sengupta
Associate Professor
CEE: Systems EngineeringCEE: Systems Engineering
University of California at Berkeley, USA
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October 21, 1999October 21, 1999
Federal Communications Commission created DSRCFederal Communications Commission created DSRC
• The record in this proceeding overwhelmingly supports the allocation of spectrum for DSRC based ITS applications to increase traveler safety reduce fuelapplications to increase traveler safety, reduce fuel consumption and pollution, and continue to advance the nations economy.
FCC Report and Order October 22 1999 FCC 99 305FCC Report and Order, October 22, 1999, FCC 99-305
Amendment with licensing rules in December 2003
75 MHz of spectrum at 5.9 GHz
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http://www.its.dot.gov/initiatives/initiative9.htminitiative9.htm
Vehicle Infrastructure Integration (VII)Vehicle Infrastructure Integration (VII)
Goal: Achieve nationwide deployment of a communications infrastructure on the roadways and in all production vehicles and to
bl b f k f d i l i h ldenable a number of key safety and operational services that would take advantage of this capability.
Background: VII builds on the availability of advanced vehicle safetyBackground: VII builds on the availability of advanced vehicle safety systems developed under the IVI and the availability of radio spectrum at 5.9GHZ recently approved by the FCC for Dedicated Short Range Communications. The VII would enable deployment of advanced
hi l hi l d hi l i f i i h ldvehicle-vehicle and vehicle-infrastructure communications that could keep vehicles from leaving the road and enhance their safe movement through intersections. These deadly roadway scenarios account for 32,000 of the 43,000 deaths annually on America's highways.
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32,000 of the 43,000 deaths annually on America s highways.
The basic idea…
Get the radios into carsGet the radios into cars
Get the radios on the road
Move lots of useful information around
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Useful Information
FromFrom http://www.vehicle-infrastructure.org/applications/
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Traffic ManagementGPS data from cars at 1 – 5 Hz1 5 Hz
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SafetySafetyApplication Space
Delay: 50 - 100 Delay: 50 100 msec
Range:150 – 200 m150 200 m
Ref: VSCC Final Report
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Cooperative Collision WarningBerkeley prototype 2004Berkeley prototype 2004
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Can be tough:Can be tough:
Message size = 200 msecRange = 150 metersVehicle density/lane = 30 meters/vehicleLanes = 8Interference range = 2* transmission rangeData rate = 3 MbpsData rate 3 MbpsOmni-antennas
With perfect schedulingA hi l t it 85A vehicle can transmit every 85 msec
Slotted Aloha efficiency = 36%
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Useful Information
FromFrom http://www.vehicle-infrastructure.org/applications/
Tough!One to one transactionsLow latency
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The community tried to standardize solutions to new networking problemsto new networking problems
Usual Wi-Fi world DSRC worldUsual Wi Fi world DSRC world
channel 1Spread the usersChoose SSIDAssociate…
watch out
DELAY!
watch out
Spread the applicationsSwitch channels fast
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channel 2
Switch channels fastScheduleNew security model…
Initially things moved fast…….y g
Spectrum for DSRC allocated in 1999:p
• http://www.fcc.gov/Bureaus/Engineering_Technology/News_Releases/1999/nret9006.html
Standardization based on 802 11a in 2001:Standardization based on 802.11a in 2001:
• Called 802.11a_Roadside then. Now IEEE 802.11p
• http://findarticles.com/p/articles/mi_m0EIN/is_2001_August_30/ai_776967200
Atheros released its first 802.11a chipset in 2001:
• http://findarticles.com/p/articles/mi_m0EIN/is_2001_Sept_5/ai_77846651p p p
• Triband chip set: 2.4, 5, 5.9 GHz
• Support for 10 and 20 MHz channels
• Channel switching in 1-2 msec
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Channel switching in 1 2 msec
Planned US VII Deployment’06
FleetNet’03
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Status of RSESunday evening, 22 Jul 07
VII California TestbedVII California Testbed
Sunday evening, 22 Jul 07
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www.viicalifornia.org
While we’ve been waiting for V2X wireless on road and car……
The same chipset
Atheros Surpasses 1 Million in Monthly Shipments of 802.11b/g and 802.11a/b/g Wireless LAN Chips; Enterprise and Home Users Fuel Rapid Growth of New Wireless LAN TechnologiesBusiness Wire July 28 2003
US DSRC penetration
• California 20
Business Wire, July 28, 2003
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• Michigan 57
• …..
7 years from chip to radio is a long time in Silicon Valley!long time in Silicon Valley!
Should we change course?
An Informed Traveler is a Safe and Efficient Traveler – Caltrans slogan
What we care about is information!
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Something happened while USDOT, Car companies have been doing DSRC…….companies have been doing DSRC…….
MobileMobileInternet
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Oops! There’s an elephant in the room..
MobileMobileInternet
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MOBILE MILLENNIUM
http://www.youtube.com/watch?v=TOi5nGCJ1YIhttp://lagrange.ce.berkeley.edu/media/media-coverage.htmlhttp://abclocal.go.com/kgo/story?section=news/technology&id=6227534
Alex BayenAssistant Professor, Systems Engineering, Civil and Environmental Engineering, UC Berkeley
Quinn JacobsonResearch Leader, Mobile Internet Services SystemsNokia Research Center Palo Alto
Similar notoriety with UAV’s
• http://blog.wired.com/defense/2008/06/video-iphone-co htmlco.html
Video: iPhone Controls Robot Plane SquadBy Noah Shachtman June 16, 2008 | 9:16:00 AMCategories: Drones, Video Fixy | gSince 2004, a team of professors and students from the University of California, Berkeley has searched for ways to let a single human supervise a team of robot planes. Now, this Center for Collaborative Control of Unmanned Vehicles has a new device for ordering around its drones: an iPhonenew device for ordering around its drones: an iPhone.In a video taken from this month's Teaching & Technology conference, the Berkeley crew uses an iPhone to pick tasks for its drone squadron, input a set of coordinates for a local reconnaissance mission, and send the planes new orders while the aircraft are in the sky.But don't tell Steve Jobs how the Berkeley folks are using his gadget. According to the terms of the Apple Software Developer Kit agreement, "applications may not be designed or marketed for real-time route guidance; automatic ornot be designed or marketed for real time route guidance; automatic or autonomous control of vehicles, aircraft, or other mechanical devices; dispatch or fleet management; or emergency or life-saving purposes."
The Mobile Internet…..
Macworld | Analysts: iPhone driving smartphone sales
Its also Quik and Twitterand Pownce and MTV…
The iPhone has had a profound effect on the smartphone market, panelists at the SmartphoneSummit said on Monday.www.macworld.com/article/132769/2008/03/iphone_market.html - 47k - Cached - Similar pages -Note this
Smartphone sales skyrocket | Tech news blog - CNET News
Smartphones are hot and getting hotter--and are outpacing the sale of laptops, according to market research firm In-Stat. Read this blog post by Marguerite ...news.cnet.com/8301-10784 3-9816072-7.html - 84k - Cached - Similar pages - Note this_ p g
Smartphone Sales To Triple, Good News For Apple, RIM, Carriers
Mar 20, 2008 ... Smartphone sales are projected to more than triple worldwide in the next six years, from 10% of the overall mobile phone market last year to ...
ll i id /2008/3/ h l i l d f l i i 35kwww.alleyinsider.com/2008/3/smartphone_sales_to_triple_good_news_for_apple_rim_carriers - 35k - Cached - Similar pages - Note this
Gartner Says Worldwide Smartphone Sales Grew 29 Percent in First ...
Jun 6 2008 Worldwide smartphone sales to end totaled 32 2 million units a 29 3 percent increase
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Jun 6, 2008 ... Worldwide smartphone sales to end totaled 32.2 million units, a 29.3 percent increase from the first quarter of 2007, according to Gartner, ...www.gartner.com/it/page.jsp?id=688116 - 30k - Cached - Similar pages - Note this
While DSRC has been trying to put wireless in the car……..
++WiFi i= WiFi in
the car!
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SAFE TRIP Inspiration: SmartWay 2007
• SmartWay: Exhibition and operational test of• SmartWay: Exhibition and operational test of second generation ITS in Japan
– 1,650 Exhibition attendees; 35 media outlets– Ongoing Tokyo field test; 60 vehicles
• Adds DSRC-enabled capabilities to existing ITS• Adds DSRC-enabled capabilities to existing ITS infrastructure:
– 163 TMCs; 2,800 cameras; 180,000 traffic sensors;
– Vehicle Information Communications System– Vehicle Information Communications System (VICS) with 33,000+ communications beacons; FM radio
• Builds upon installed base of ITS users:– 21 6 Million ETC units; 71% of transactions overall– 21.6 Million ETC units; 71% of transactions overall– 28.3 Million navigation units; 19.6 Million VICS
• Motivated by distinctive Japanese conditions– Complex street addressing and navigation
Expressways built to lesser “parkway” standards– Expressways built to lesser parkway standards– Serious motor vehicle crash rate 5X U.S– Vehicle density 10X U.S.; congestion / limited
parking– $5.60 / gallon fuel; ~$0.40 / mile expressway tolls
The New Approach – The Old Waypp y
V2V Safety Intersection Tolling… Probe Data…
Internet: IP, Multicast, IPSec, WPA, http……
DSRC WiFi 3GDSRC WiFi 3G
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Damn these Europeans….How do they get it right?g g
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The New Approach – The Old Waypp y
V2V Safety Intersection Tolling… Probe Data…
Internet: IP, Multicast, IPSec, WPA, http……
DSRC WiFi 3GDSRC WiFi 3G
DSRC may rise of fall Information survives
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Lots of inefficiencies, no QoS, waste bandwidthBut its out there :(
New approach needs new f i d
Hi, I’m transportation exec!
friendsHi, I’m your old
friend Car Company
Hi, I’m New. My nameIs Iphone
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Th C t d T l PThe Connected Traveler Program
Caltrans, USDOT-RITA, MTC
Two projects
• Mobile Millenium: Berkeley, Nokia, Navteq
• GEMS – Networked Traveler: Berkekey, Nissan, Navteq
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Get yourself a smartphone and go to www.networkedtraveler.org (Demo only…)www.networkedtraveler.org (Demo only…)
Choose whatChoose what information you want to put in
And what you want to take out.
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Get yourself a smartphone and go to www.networkedtraveler.orgg
Choose whatChoose what information you want to put in
And what you want to take out.
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Then go out into the world with your t h i k tsmartphone in your pocket…..
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Plan your tripa you t p
N800 movieN800 movie
Iphone movie
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Rich view of commuting convenience…GEMS t i l i i lti d l lti it iGEMS trip planning is multi-modal multi-criteria
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GEMS trip planning is multi-modal multi-criteria
Rich view of commuting convenience…
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If you are riding the bus…y g
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Your Smartphone based personal mobility assistant stays trip awareassistant stays trip aware
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Transit Signal PriorityUse your phone to let the light know you’re comingUse your phone to let the light know you re coming….
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If you are driving…Content available to the networked travelerContent available to the networked traveler
Map basedMap based
Quasi-dynamic
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If you chose pedestrian alerts on your networked traveler pagepage….
Watch out for me!
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Get yourself a smartphone and go to www.networkedtraveler.orgg
Choose whatChoose what information you want to put in
And what you want to take out.
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The Networked Traveler Concept:Social Networking for Smarter MobilitySocial Networking for Smarter Mobility
If I don’t put information in there won’t be any for you to take outIf I don t put information in there won t be any for you to take out….
The Pitch?
Welcome to the world of the Networked Traveler! An easy way to put in and take out information for smarter personalized travel. Get a smartphone and browse www.networkedtraveler.org.
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What will happen to DSRC/VII?pp /
Many of its local information dissemination applications will be realized by the Mobile Internety
• Traffic density, parking, accident reports, ….
So will Soft safety / Situation Awarenessy
• Signage, Careful stopped traffic ahead…
However Smartphones get WiFi into cars
• Is the ad-hoc mobile network finally coming to life?
Ride a new convergence of the mobile Internet and car industry…
• Will ad-hoc information protocols, hotspot protocols, DSRC chipsets go into smartphones……
C ti C lli i W i t ki i d d
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Cooperative Collision Warning, cars tracking cars, remains a deep and interesting application not for the mobile Internet
PaperspRezaei S, Sengupta R, Krishnan H. Reducing the communication required By DSRC-based vehicle safety systems. Proceedings of the 2007 IEEE Intelligent Transportation Systems Conference. IEEE. pp. 361-6. October 2007
R i S S R K l fil b d i i f d d hi l f l li iRezaei S, Sengupta R. Kalman filter-based integration of dgps and vehicle sensors for localization. [Journal Paper] IEEE Transactions on Control Systems Technology, vol.15, no.6, November 2007, pp. 1080-8. Publisher: IEEE,USA.
Shladover S.E., Polatkan G., Sengupta R. VanderWerf, J., Ergen, M., Bougler, B. Dependence of Cooperative Vehicle System Performance on Market Penetration Transportation Research Record:Cooperative Vehicle System Performance on Market Penetration Transportation Research Record: Journal of the Transportation Research Board No. 2000, Transportation Research Board, November2007
Sengupta R., Rezaei S., Shladover S.E., Cody D., Dickey S., Krishnan H. Cooperative Collision Warning Systems: Concept Definition and Experimental Implementation. Journal of Intelligent T i S V l 11 N 3 T l & F i J l 2007Transportation Systems, Vol. 11 No. 3, Taylor & Francis, July 2007
Qing Xu, Mak T, Jeff Ko, Sengupta R. Medium access control protocol design for vehicle-vehicle safety messages. IEEE Transactions on Vehicular Technology, vol.56, no.2, March 2007, pp. 499-518. Publisher: IEEE,USA.
T. K. Mak, K. P. Laberteaux R. Sengupta. A Multi-Channel VANET Providing Concurrent Safety and Commercial Services. In Proceedings of the 2nd ACM international workshop on Vehicular ad hoc networks, 2005, Cologne, Germany, Pages: 1 – 9.
M. Zennaro, R. Sengupta. Distributing Synchronous Programs Using Bounded Queues.
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e a o, Se gup a s bu g Sy c o ous og a s Us g ou ded QueuesIn proceedings of EMSOFT 2005, Jersey City, USA.
Xu, Q., Mak, T., Ko J., Sengupta R. Vehicle-Vehicle Safety Messaging in DSRC. In Proc. of the 1st ACM Workshop on Vehicular Ad-hoc Networks, October 2004, Philadelphia, USA.
The ENDCollaborators
PATHPATH• Jim Misener, Co-Investigator GEMS
• Dr. Susan Dickey, Manager Software Group
• And many of the technical staff• And many of the technical staff
CEE: Systems• Prof. Alex BayenProf. Alex Bayen
• Students: Ching-ling Huang, Shahram Rezaei, Christian Manasseh, Jerry Jariyasunant, Dan Work
EECS
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EECS• Prof. Kannan Ramanchandran
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The community has been working on these problems for four yearsp y
We need some visible successes to attract people, companies, funding (NSF), etc
• Community is not growing• Community is not growingThe registration information and papers in this field stays roughly the same size over years
WHY?
• Some “google trend” info (please remove or revise)
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Examples of highly visible activities (successes?)
DARPA urban challengeDARPA urban challenge• autonomous vehicle capable of driving in traffic (Link, video clips),
Mobile millennium • Use 3G to transfer real time sensing results from cars on highway, and to deliver real
time info to vehicles (video).
• http://traffic.berkeley.edu/
l di d li htt //t ffi b k l d / l ht l• several media and news clips on: http://traffic.berkeley.edu/newsreleases.html
Japan Smartway demostration• http://www.smartway2007.jp/en/index.htmlhttp://www.smartway2007.jp/en/index.html
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What are the large programs dedicated to these problems?p
Japan: Smartway
Europe: CVIS consortium, Cooperative Vehicle Infrastructure Systems (video)
US: VII (link)• Expect to install 250,000 APs
• Now: 25 AP in California (not Fed funded); 57 AP in Michigan (Fed funded)• Now: 25 AP in California (not Fed. funded); 57 AP in Michigan (Fed. funded)
Are these good enough?
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Sales of 802.11a/b/g chipsets/ /g p
It’s growing exponentially since 2003:g g p y• huge success: Atheros alone surpassed 1,000,000 shipment per month
• http://findarticles.com/p/articles/mi_m0EIN/is_/ai_105906482
Progress and acceptability of two things created at the same time• 802 11a based solutions: Success• 802.11a based solutions: Success
• 802.11p (DSRC) for VANET: Failure
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In danger of being obsolete?g g
New technologies are coming!
• Higher data rate, wider comm. range
• 802.11n (MIMO), 802.16 (WiMAX), 802.15.3 (UWB)
Many applications are moving directly towards newer technologies, bypassing DSRC
• 802.11p and ad hoc setting is not attractive?
• Are we working on a to-be-obsolete technology?
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Obsolete in Applicationspp
One example: Mobile MillenniumOne example: Mobile Millennium
• Gathering real-time Traffic information
• Parking information
If d th il i 3G h d d 802 11 ?• If we can do those easily using 3G, why do we need 802.11p?
Some applications have been realized using other technologies
What is left for us to do?
• Safety applications needs to work in ad hoc setting; it’s not likely to be replaced by others.
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What can not be replaced by other technologiestechnologies
Ad hoc networking to support real time information exchange
• Scalability
• No infrastructure is requiredq
• Low latency requirement
Safety applications need as much resource as possible
• Do we know what’s the limit given the current channel allocation and technology?
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We don’t know how big the pipe is?g p p
The capacity of the channel depends on the location, traffic condition, etc.
This is a multi-accessed channel
• Shared by all the cars/nodes
What we learn from TCP is that we can still do well without knowing how big the pipe ishow big the pipe is
• The sender can adapt its rate to utilize the channel as much as possible
• All users can share the “pipe” fairly
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Shannon’s capacity bound and Turbo coding (1/2)(1/2)
A good example of knowing what’s the limit and approach to itA good example of knowing what s the limit and approach to it
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Shannon’s capacity bound and Turbo coding (2/2)(2/2)
100
SNR vs. BER for rate 1/2 codes
10-1Year Rate ½ Code SNR Required for BER
< 10-5
10-3
10-2
BER Iterative
Code
Uncoded1948 SHANNON 0dB
1967 (255,123) BCH 5.4dB
1977 Convolutional Code 4.5dB
10-4
10Conv. Code ML decoding
CapacityBound
C Berrou and A Glavieux "Near Optimum Error Correcting Coding And Decoding: Turbo-
1993 Iterative Turbo Code 0.7dB
2001 Iterative LDPC Code 0.0245dB
4 dB
0 1 2 3 4 5 6SNR
O k h th b d i
C. Berrou and A. Glavieux, Near Optimum Error Correcting Coding And Decoding: TurboCodes," IEEE Trans. Comms., Vol.44, No.10, Oct 1996.
4 dB
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Once we know where the bound is, we can work on approaching to it!
Sahai’s anytime capacity and its relationship with tracking a dynamical system
Shannon’s capacity definition is not sufficient for us to judge whether a channel can support tracking of a dynamical systempp g y y
A new definition from A. Sahai tells us what should be the notion of capacity when the channel is used in control loop.
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Definition of Anytime Reliability and Anytime Capacityy p y
Anytime ReliabilityAnytime Reliability
Error probability is gradually decreasing with time…
(Message accuracy is increasing with time)
Anytime Capacityy p y
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Anytime Capacity for BEC
Shannon’s capacity
eP2log−
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Control Stability and Channel Reliabilityy
What channel reliability one can achieve given Observer & Controller with known stability?
DataControl driven partControl driven part
Noise driven partp
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Uniform source rate assumptionp
Usual assumption while analyzing VANETUsual assumption while analyzing VANET
• Each node has homogeneous source producing the same information rate
• Various simulation is done to explore what rate is possible given current spectrum allocation and DSRCspectrum allocation and DSRC
Message dispatcher idea to reduce message amount
• but it still assume homogenous traffic from each nodeg
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Review of Non-adaptive resultsp
Curve of beacon rate and throughputCurve of beacon rate and throughput
• Throughput increases before hitting the capacity
• Then it decreases fast after reaching capacity
Is this good enough?Is this good enough?
• If yes, we can all go home!
• If no, how good it can be?
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Slotted ALOHA to understand the available per node throughputper node throughput
Si l l f h i f i i il bl dSimple example of what information is available to every node• The information amount vanishes to zero as node number increases
111Per node throughput vanishes to zerosenders 01)11(1 1 →≈− −
nennn
receiver
Total throughput
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Total throughput
%361)11( 1 ≈→− −
enn
Power control to share the channel
One approach to maintain per node throughput as acceptable level:One approach to maintain per node throughput as acceptable level:
• Reduce the number of nodes sharing the channel
• A common approach is to reduce comm. range so that appropriate amount of nodes will share the channelof nodes will share the channel
Information exchange happens locally since neighboring cars are more physically involved than remote ones
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Power control from Hartenstein
Assumptions:Assumptions:• The Carrier Sense Range is monotonic
• All nodes have the same beaconing frequency and packet sizes
• All nodes have the same Maximum Transmission Power (Pmax)( )
Fair Power Control:• All vehicles in a certain (busy) area must restrict their beacons’ transmission power
by the same ratioby the same ratio
• Maximize the minimum transmission power
• Maximize individual coverage
Above combines with various channel models
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Rate adaptation (based on estimation error) can be helpfulcan be helpful
S d i iSources produce time-varying rates
• Especially for vehicle safety (estimation purpose)
• Rate of the source depends on the estimation error of the dynamic process
• Communication happens only when it is necessary to release information
• This enables multiplexing gain and better sharing the precious channel capacity
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Fixed Rate Communication
Measurements Measurements
SV
Self EstimatorOV
wor
k
Measurements
Fi d P i diSelf Estimator
Measurements
(Kalman Filter)
Net
wFixed Periodic (Kalman Filter)
Sources produce the same amount of information
• Periodical beaconing• Periodical beaconing
• Communicate even when it’s not necessary
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Variable Rate Communication
SVS lf E i
OVNeighbor Estimatorsrk
Measurements
Self Estimator(Kalman Filter)
Neighbor Estimators(Kinematic Eq.’s)
Net
wor
Scheduler
Remote Estimator(Kinematic Eq.’s)
SV: Subject VehicleNeighbor Estimators
(Kinematic Eq.’s)
NE1 NE2 NEn
. . .
SV: Subject VehicleOV: Other Vehicle(s)
Sources communicate when it’s necessary to release information
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Averaged Tracking Error: Variable Rate vs. Periodic
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Tracking Error tail probability:Variable Rate vs. Periodic
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Averaged Tracking Errors:Variable Rate with Repetition
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Tracking Error tail probability: Variable Rate with Repetition
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Error-dependent policy (1/3):MSE lower bound
E h d d id it T b bilitEach node decides its Tx. probability:• Comm. rate:• Error sensitivity:
T b bilit• Tx. probability:
Lower bound of MSE: • Achieved by all “renewal-type” comm. policies(Round-robin MSE)Necessary condition for optimal sensitivity
⇒Minimum MSE is achieved only when expected inter-
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Minimum MSE is achieved only when expected inter-arrival time equals the number of nodes.
Error-dependent policy (2/3):Sensitivity to errory
Necessary condition for sensitivity:Necessary condition for sensitivity:
Optimal sensitivity (Matlab simulation results)p y ( )
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Err-Coll-Dep policy (1/2):formulation
Improved version of Error-dependent• Use channel collision as indicator to infer the channel condition
Each node decides its Tx. probability:• Comm. rate:
• Error sensitivity:
• Collision sensitivity:
• Tx. probability:,,
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Err-Coll-Dep policy (2/2): comparison with Err-Depp
Matlab simulation results
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Optimal collision sensitivity: \betap y \
It t t \b t ’ ti l l 25~30It turns out \beta’s optimal value: 25~30, • independent of node number!
• During congested channel:When beta <25 not enough backoffWhen beta <25, not enough backoff
When beta >30, too much backoff
Beta=9 or 39 Beta=29
E E
MSE
MSE
rate rate
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rate rate
Short Summaryy
For various applications we need visible successes and re-think whatFor various applications, we need visible successes and re-think what is the right technology to work on
For active safety using DSRCy g
• (rate, range) adaptive schemes can outperform non-adaptive ones
• Besides range/power control, we can also adapt rate based on estimation error of dynamical system and channel congestiony y g
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The VANET Communityy
VANET 2004 – 2008VANET 2004 – 2008
V2VCOM 2005 - 2008
About 15 papersAutonet 2006 - 2008
Wivec 2007 - 2008
About 15 papersa meeting
MOVE 2008
ISVCS 2008ISVCS 2008
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A Healthy CommunityA Healthy Community….
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Boy! These guys like to talk!Boy! These guys like to talk!
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But more seriouslyBut more seriously……
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What have us little guys been doing?My quick survey…..y q y
Decentralized Information ApplicationsDecentralized Information Applications
• Traffic density estimation, parking, accident reports..
• Application level and routing (geo, multicast….)
Learning the V2V channel
• More recently using it for antenna or phy design
Safety
• Cooperative Collision Warning, Intersection collisions, …
Tools, Simulators, Network models…
Roadside to Vehicle
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Roadside to Vehicle
• Examples: Mauve’08, Laberteaux’05
Patting ourselves on the back 1Decentralized Information ApplicationsDecentralized Information Applications
Examples:Jerbi’07
Examples:
Accident report, parking, data disseminsation, traffic ,monitoring • Okada’ 08, Jerbi’07,
Sormani’06, Caliskan ’06, Iftode’05Iftode 05
Protocols• Car torrent Gerla’07
• Multi-cast Ozguner’04. Lee’08
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Patting ourselves on the back 2Understanding the V2V Channel and …Understanding the V2V Channel and …
Channels• Stancil’07• Ramachandran’07• Spies’07
Zhang’08
Spies 07• Taliwal’05
Antennas and Phy d idesign• Bahai’08• Malarky’07,
Subramaniam’07Subramaniam 07
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Patting ourselves on the back 3Tools, Network Models, SimulatorsTools, Network Models, Simulators
Rajkumar’05 Hartenstein’07Rajkumar 05
Bagrodia’06
H i ’06Hartenstein’06
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Patting ourselves on the back 4SafetySafety
Sengupta’04 200
250
al (m
s) FeasibleSengupta’04
Sengupta 04
Elbatt’06150
200
tion
Inte
rva
Labersteaux’06
Hassan’08 100
age
Gen
erat
I f iblJiang’08
Hartenstein’08
50Mes
sa Infeasible
00 50 100 150 200 250
Number of Interfering Vehicles
91
CEE: SystemsUCB
FCW Broadcast Rate FCW Broadcast Rate AdaptationAdaptation
• Motivation: balance the factors
pp
contributing to the packet Inter-reception time (IRT)
– # consecutive packet losses: favors low broadcast rateslow broadcast rates
– Inter-broadcast interval: favors high broadcast rates
• High density scenario 150 m• High density scenario, 150 m range, 100 Bytes payload
• Examine different Broadcast intervals:
– 50, 100, 200, …, 700 msec
Conjecture: There is an optimal broadcast interval that minimizes IRT
Rate Adaptation Rezaei Phd thesis’08Huang IEEE MSC’08p
94
CEE: SystemsUCB
DSRC is local area networksDSRC is local area networks
Transit Signal Priority
Traffic Signal
Transit Vehicle
Transit Vehicle Stop
up to 1000 ft
g y
Grass DividerCollision Avoidance
E-Transaction: gas, movie, ….
Gas Pumps
95
Not to Scale
IDB Data Transfer * Graphic created from Broady Cash (ARINC)
DSRC as per FCC Ruling in 2004
• DSRC has 75 MHz Spectrum (1 control channel, 6 service channels)• DSRC supports the non-exclusive geographic area licensing
– Each licensee can operate any of the service channels– A license is for an area-of-operation (e.g., county, state…)
• Control channel is for safety messages and service announcements– Three levels of priority: Safety of Life, Safety, Non-Safety
• The service channels are used for non-safety related data traffic (e.g. e-commerce, infotainment)
• ASTM standards committee voted in 2000 to base it on 802.11a
96
– Now IEEE 802.11p
Typical DSRC Data Traffic Requirements
Application Packet Size(Bytes)
/Bandwidth
Allowable Latency
(ms)
NetworkTraffic Type
Comm. Range (m)
Priority
Intersection Collision Warning / Avoidance
~100 ~100 Event 50 – 300 Safety of Life
Forward Collision Warning ~100/ ~100 Periodic 50 – 300 Safety of ~10Kbps Life
Work Zone Warning ~100~1Kbps
~1000 Periodic 50 – 300 Safety1Kbps
Transit Vehicle Signal Priority
~100 ~1000 Event 300 – 1000 Safety
Toll Collection ~100 ~50 Event ≤15 Non SafetyToll Collection ~100 ~50 Event ≤15 Non-Safety
Service Announcements ~100/~2Kbps
~500 Periodic 0 – 90 Non-Safety
97
Movie Download (2 hours of MPEG 1) : 10 min. download time
> 20Mbps N/A N/A 0 – 90 Non-Safety
New approach needs new f i d
Hi, I’m transportation guy!
friends
Hi I’mHi, I m your old
friend Car Company Hi, I’m New. My name
Is Iphone
98
CEE: SystemsUCB