wireless broadband access for the automobile: applications and enabling technologies

CMU/GM Collaborative Research Lab

Wireless Broadband Access for the Automobile: Applications and Enabling

Technologies

Dan Stancil

Acknowledgements: Ratish Punnoose, Stanley Wang, Richard Tseng, He Huang,

James Casazza, James Grace, Jessica Hess, Kevin Borries, Jacob Meyers, Tony Nolla,

Priya Narasimhan, Ed Schlesinger

Jay Parikh

July 29, 2003


Outline

• Where we’ve been• Where we’re going


Wireless Networking: Where We’ve Been

• Understanding– Interference between Bluetooth and 802.11b characterized– Basic understanding of noise from small number of interferers established

(Ph.D. thesis)– Coverage of 2.4 GHz signals within a vehicle for different antenna

placements

• Infrastructure– Communications Resource Management using CORBA middleware:

• Scalable, flexible architecture proposed• Demo of interactions between cellphone agent, CD player agent, speech

agent, and sound agent (Video demo available)


Co-existence in Unlicensed Bands

• A number of wireless technologies are in use in the unlicensed bands.– 802.11, Bluetooth, ITS services, many proprietary point-to-

point wireless connections.

• Future wireless technologies are likely to use the ISM bands.– No need for licenses, rather wide bandwidth, worldwide

availability, decreases time to market.


Interference

• These wireless devices share the frequency spectrum.

• Operation of devices interferes with the working of other devices using the same band.

• Effects can be seen as:– Reduced data rate.– Increased error rate.– And sometimes, a failure to operate.

• Exact behavior of co-existing devices is not well-characterized.


BT Interference on 802.11b

A TT

VA

RA

TT

AT

T

AT

T

802.11b TxLaptop

802.11b RxLaptop

BTLaptop

BTLaptop

Attenuator

VariableAttenuator

DirectionalCoupler

Pow erSplitter

Isolator

Tx

Tx

Rx

Rx

-6dB


Performance of 802.11b with Bluetooth Interference

-55 -50 -45 -40 -35 -30 -25 -200

5

10

15

20Signal strength =-61dBm

% l

os

t p

ac

ke

ts

S/I in dB

-55 -50 -45 -40 -35 -30 -25 -200

20

40

60Signal strength =-61dBm

% l

os

t p

ac

ke

ts

11 Mbps

2 Mbps


Time

Frequency

802.11 Packet

Bluetooth Packet

Theory for 802.11/Bluetooth Interference


Noise Distribution

• The noise values have a probability distribution.


PDF of Gaussian Noise + Interference


In-vehicle Communication

• Vehicle will likely participate in local 2.4 GHz networks with personal electronic devices– Bluetooth– Wi-Fi

• Unobtrusive antennas are needed that can be camouflaged

• Optimum antenna placement decreases power and reduces interference to other electronics– Useful to know the propagation coverage within the vehicle


Test Vehicle Setup

• Pontiac Montana• Transmitting antenna placed on dashboard and

ceiling• Empty vehicle, and with driver

Dash Ceiling


Effect Of People

• Obstruction by the driver or other passengers


Results Showing Effect of Driver

-60

-55

-50

-45

-40

-35

-30

-25

0 100 200 300

0

50

100

150

Side of Car (cm)

Fro

nt

of

Ca

r (c

m)

Dash location without driver

-60

-55

-50

-45

-40

-35

-30

-25

0 100 200 300

0

50

100

150

Side of Car (cm)

Fro

nt

of

Ca

r (c

m)

Dash location and driver present

dB loss


Communication Components of CMU/GM Vehicle Testbed

Palm/PDA

Jog Dial/ Mouse Wheel

Microphone

Speakers

Finger Print

RecognitionDigital

Camera

Temperature Sensor

CDPD Modem

GPS Receiver

PDA Cradle

Vehicle’s ECU - RPM, MPH,

etc

Firewire Controller

Serial Controller

Sound Card

VGA Controller

Touch Screen

WaveLAN

CellPhone

USB Controlle

r

USB Controller

Serial Controller

USB Controller

Firewire Controller

TV CardEtherNet

Radio Card

Acknowledgement: Asim Smailagic, Dan Sieworek, Rapid Prototyping Class (Fall 2001)


Communication System Architecture Goals

• Provide support for different data service requirements.

• A manager to arbitrate resources.• Provide easy access to commonly used

functions (eg. GPS)• Provide a framework for building software

agents that have to interact with each other.• Minimal change to existing applications.


GPS

Proxim ityAlert

ITS/Em ergency

Info

Com m unicationsResource Manager

QOS basedData Routing

Traffic going to theoutside

Internet AccessChannels

Per-link QOSinformation

TV, AM, FM, DAB,Cellular CallRequest

Publisher/Subscriber Transport usingthe CORBA Event Service

FuelSensor

RoutePlanner

C O R B A In terfaceD irect In te ractionEvent D istribu tion

Software Interaction using CORBA


Demo Video


Middleware Comparisons

CORBATAO/C++

CORBATAO/C+

+

OSGi

J2EE

OSGi

J2EE

Mean: 163SD: 6.5

Mean: 12.5SD: 110.0

Mean: 45700.5

SD: 18750.5

CORBA Java IDL

CORBA Java IDL

Mean: 796.0SD: 638.0

Client Server


Where We’re Going

• Understanding– Peer-to-peer propagation channel at 2.4 GHz and 5-6 GHz

• Infrastructure– Van experimental infrastructure update– Peer-to-peer wireless links using technologies such as Bluetooth and

802.11a,b,g– Middleware testbed for agent and communication resource architecture

and management– Intelligent mobile IP client

• Applications– DSRC– Short-range transactions– Real-time traffic information


Experimental Van: Before & After

Original infrastructure

Updated infrastructure


Peer-to-Peer Networking

• Exchange of emergency/traffic information• “Walkie-talkie” style communication between

vehicles• Allow one vehicle to function as a network

portal for nearby vehicles• Exchange of diagnostic information• Facilitate platoon formation for efficient

highway travel


Peer-to-Peer Testbed

• Collect extensive propagation data between vehicle pairs using different frequencies and technologies– 802.11b, 802.11a, UWB

• Enable demonstrations of application concepts

• Results will facilitate selection of most promising technologies

• Provide GM with background to influence evolving standards


Vehicle Mobility in the Internet

• A vehicle may have a different Internet address for each network attachment point.

• This allows it to access Internet servers but it is not easily accessible due to changing IP addresses.

• The vehicle needs to be accessed for diagnostics and status information.

• Mobile IP provides seemingly continuous Internet access to its Mobile Hosts by obtaining an IP address from its Home Agent.

• With Mobile IP each vehicle can be addressed using a single IP address, regardless of the point of connection.


Mobile IP Design

.Application

TCP/UDP

IP (routing)

CN

HA

Foreign Network

MN

Home Network

FA

Basic Entities:MN = Mobile NodeHA = Home AgentFA = Foreign AgentCH = Correspondent Node


Advantages of MoIP

• Transparency– Continue using its home address.– Ability to communicate after disconnect & reconnect.– Change its point of attachment.

• Compatibility– Support of any lower layer that IP runs on.– No change to ordinary hosts and routers.– Communicate with unaware nodes.


Birdstep Intelligent Mobile IP Client

Note: FA only required under certain circumstances, such as NAT traversal

• Allows seamless roaming between networks without having to restart VPN session!

• Presently being installed at CMU


Proposal: Traffic Companion

• Pittsburgh has an extensive network of traffic condition sensors

• Mobility Technologies, Inc. (http://www.mobilitytechnologies.com) is commercializing this technology

• http://www.traffic.com/Pittsburgh/index.html• PennDOT has an extensive network of traffic

cameras• http://www.epenndot.com/traffic_cams.php#


Traffic.com map

http://www.traffic.com/Pittsburgh/index.html

• Map updated every minute


PennDOT Traffic Cam Images

http://www.epenndot.com/traffic_cams.php#

• Images updated every minute


Could we put access to this in the vehicle?

• Connectivity via Verizon 1X wireless data + hotspot roaming

• Real-time traffic conditions• Just-in-time route planning• Using cyclic patterns to predict best route• Useful but non-distracting graphical interface


Summary

• Past Projects– Unlicensed coexistence– Communications Resource Management using Middleware– 2.4 GHz propagation coverage in and around vehicle

• Future Directions– Peer-to-peer test bed

• Propagation channel• Middleware architecture

– Mobile IP Intelligent client for seamless roaming– CMU Traffic Companion for real-time traffic planning


For More Information

• “Interference Between Devices in the ISM Band.” - Ratish Punnoos/Dan Stancil

• “Antenna Placement in Vehicles: Electromagnetic Propagation at 2.4 GHz.” - James Casazza, James Grace, Ratish Punnoose, Dan Stancil

• “Communications Resource Management for Advanced Telematics Applications.” -Richard Tseng, Ratish Punnoose, Stanley Wang, Dan Stancil, Ed Schlesinger

• Communications Resource Manager Video- Stanley Wang• “Interoperability, Performance Evaluation and Adaptation of CORBA,

OSGi and J2EE for Telematics Applications.” - He Huang, Ratish Punnoose, Priya Narasimhan, Dan Stancil

• “Peer-to-Peer Unlicensed Communication Between Automobiles.” - James Casazza/James Grace

• “Wireless Broadband Access for the Automobile: Applications and Enabling Technologies.” - James Casazza/James Grace

wireless broadband access for the automobile: applications and enabling technologies

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