Vehicle Safety Communications Project VSC Progress Briefing #2 – Task 4 Field Testing –

11November 4th, 2003November 4th, 2003 Vehicle Safety Communications ConsortiumVehicle Safety Communications Consortium

Vehicle Safety Communications ProjectVehicle Safety Communications ProjectVSC Progress Briefing #2VSC Progress Briefing #2

– – Task 4 Field Testing –Task 4 Field Testing –

Overview of Hardware and SoftwareOverview of Hardware and Software

Test Track ResultsTest Track Results


OutlineOverview of Hardware and Software

Test Equipment and Interface

Format of Data/Findings

Test Track Testing

Test Track Facilities

Static Results

Dynamic Results

Multipath Considerations

Conclusions


Test Equipment

VSC VSC Communication Communication Test Kits (CTKs)Test Kits (CTKs)

Laptops with Laptops with 802.11a card802.11a card

DGPS receiversDGPS receivers Magmount DSRC Magmount DSRC

and DGPS and DGPS antennasantennas

Portable Portable implementationimplementation


CTK S/W v2.3CTK S/W v2.3 CTK S/W v2.7CTK S/W v2.7 DSRC StandardDSRC Standard

25/50 mW default 25/50 mW default antenna input power antenna input power settingssettings

Up to 100 mW Up to 100 mW programmable programmable antenna input powerantenna input power

Up to 750 mW variable Up to 750 mW variable antenna input powerantenna input power

5.15-5.35, 5.725-5.825 5.15-5.35, 5.725-5.825 GHzGHz

5.15-5.35, 5.725-5.15-5.35, 5.725-5.825, 5.85-5.925 GHz5.825, 5.85-5.925 GHz

5.85-5.925 GHz5.85-5.925 GHz

20 MHz channel20 MHz channel 10 MHz channel10 MHz channel 10 MHz channel10 MHz channel

Real-time rangeReal-time range Real-time rangeReal-time range N/AN/A

Unknown RSSIUnknown RSSI Real-time RSSIReal-time RSSI N/AN/A

Pre-set channelPre-set channel Selectable channelSelectable channel Channel switchingChannel switching

Diversity antennasDiversity antennas Diversity with manual Diversity with manual overrideoverride

N/AN/A

IEEE 802.11 Ad hocIEEE 802.11 Ad hoc DSRC Ad hocDSRC Ad hoc DSRC Ad hocDSRC Ad hoc

6-54 Mbps6-54 Mbps 3-27 Mbps3-27 Mbps 3-27 Mbps3-27 Mbps

CTK Configuration


CTK Sender Interface

Broadcast durationBroadcast duration Update rate Update rate Packet sizePacket size

dy1

dx1


CTK Receiver Interface

Packet numberPacket number OS/GPS timestampOS/GPS timestamp DGPS location DGPS location

coordinatescoordinates

dy1

dx1





Test Track Testing


Static Results

Dynamic Results


Conclusions


Format of Data/Findings Received packets (in green)Received packets (in green) Lost packets (in red)Lost packets (in red)

Received packets (in green)Received packets (in green)


Format of Data/Findings Packet number on left axis Packet number on left axis Accumulated packets (in black)Accumulated packets (in black)

Packet number on left axis Packet number on left axis


Format of Data/Findings Distance between antennas (in blue)Distance between antennas (in blue) Distance value on right axisDistance value on right axis

Distance between antennas (in blue)Distance between antennas (in blue)


Effect of GPS satellite obstruction





Test Track Testing


Static Results

Dynamic Results


Conclusions



Controlled environmentControlled environment

Two-lane test roadTwo-lane test road

Straight-away with rural Straight-away with rural surroundingssurroundings

Overhead bridge can Overhead bridge can disrupt GPS signaldisrupt GPS signal

OverheadBridge

TestTrack





Test Track Testing


Static Results

Dynamic Results


Conclusions

x

y

z

v2v1

dy1

dx1

Sender

Receiver

Legend:

Two Static Antennas


Two Static Antennas 200m range, 200 bytes, ~100 msec update rate200m range, 200 bytes, ~100 msec update rate Direct Line of Sight (LoS), no packet lossDirect Line of Sight (LoS), no packet loss

x

y

z

v1 v2

dy1

dx1


Two Static Antennas Obstructed LoS (stationary SUVs)Obstructed LoS (stationary SUVs) No packet loss at various distancesNo packet loss at various distances

dy

1

dx1

1 2 3


Two Static Antennas 35m range, obstructed LoS (large box truck)35m range, obstructed LoS (large box truck) Vehicles positioned laterally – no packet lossVehicles positioned laterally – no packet loss

x

y

zv2

v1

dy1

dx1


Two Static Antennas 39m range, obstructed LoS (large box truck)39m range, obstructed LoS (large box truck) Positioned longitudinally – some loss of packetsPositioned longitudinally – some loss of packets

x

y

z

v2v1

dy1





Test Track Testing


Static Results

Dynamic Results


Conclusions

ffv2

x

y

z

dy1

dx1

(RSU)

1

Legend:

Sender

Receiver

One Dynamic Antenna (OBU)One Static Antenna (RSU)

Obstructer


One Dynamic, One Static Antenna Receiving vehicle ~60 mphReceiving vehicle ~60 mph No packet lossNo packet loss

v1

dy1

dx1

x

yz


One Dynamic, One Static Antenna Transmitting vehicle ~60 mphTransmitting vehicle ~60 mph A few lost packetsA few lost packets

v2

x

yz

dy1

dx1

(RSU)


One Dynamic, One Static Antenna Transmitting vehicle ~20 mphTransmitting vehicle ~20 mph A few lost packetsA few lost packets

v2

xy

zdy1

dx1

(RSU)


One Dynamic, One Static Antenna Receiving vehicle ~40 mph, with obstructionReceiving vehicle ~40 mph, with obstruction No packet lossNo packet loss

v1

dy1

dx1


One Dynamic, One Static Antenna Transmitting vehicle ~40 mph, with obstructionTransmitting vehicle ~40 mph, with obstruction No packet lossNo packet loss

dy

f

v2

x

y

z

dy1

dx1

(RSU)





Test Track Testing


Dynamic Results


Static Results

Conclusions

v1v2

dy1

dx1

1

Legend:

Sender

Receiver

Obstructer

Two Dynamic Antennas (OBUs)


Two Dynamic Antennas 2 vehicles ~ various speeds, same direction 2 vehicles ~ various speeds, same direction Distances up to 150 m, no packet lossDistances up to 150 m, no packet loss

x

y

z

v1v2

dy1

dx1


Two Dynamic Antennas Various speeds, same direction, ~150 m rangeVarious speeds, same direction, ~150 m range Cut-in SUV, no packet lossCut-in SUV, no packet loss

v1v2

dy1

dx1


Two Dynamic Antennas Sender vehicle and SUV brake to a stopSender vehicle and SUV brake to a stop Lost packets are likely due to SUV obstructionLost packets are likely due to SUV obstruction

dx

v1

v2

dy

(Comes to STOP)dx

v1

v2

dy

(Comes to STOP)dx

v1

v2

dy

(Comes to STOP)


Two Dynamic Antennas Receiver passes sender braking from 30 – 0 mphReceiver passes sender braking from 30 – 0 mph Packet loss at ~ 90 mPacket loss at ~ 90 m

x

y

z

v1

v2

dy1

dx1


Two Dynamic Antennas Sender and receiver pass at 50 mphSender and receiver pass at 50 mph ~50 msec, 400 bytes, no packet loss~50 msec, 400 bytes, no packet loss

x

y

z

v1

v2

dy1

dx1


Two Dynamic Antennas Sender and receiver pass at 30 mphSender and receiver pass at 30 mph Packet loss at ~ 90 mPacket loss at ~ 90 m

x

y

z

v1

v2

dy1

dx1





Test Track Testing


Static Results

Dynamic Results


Conclusions



Two-Ray Ground Multipath ModelTwo-Ray Ground Multipath Model

EEtotal total = E= EDD + E+ ERR(e(ejj ))

EEmin min = E= EDD – E– ERR when when = = ππ

D: Direct Line of Sight

R: Reflected Line of Sight


Multipath Considerations Null spot found through slow-rolling testNull spot found through slow-rolling test Loss of packets between ~ 87 m and 94 mLoss of packets between ~ 87 m and 94 m

Track entrance

SUV – sender stopped. Facing west

LeSabre - receiver driving on the shoulder towards

SUV.

Facing East.

overpass

West


Multipath Considerations Steady state test at ~ 92 m null spotSteady state test at ~ 92 m null spot Almost complete loss of packetsAlmost complete loss of packets

v2v1

dy1

dx1


Test Track Conclusions Single-sender, single-receiver DSRC under direct LoS Single-sender, single-receiver DSRC under direct LoS

conditions is robust for a variety of vehicle-vehicle and conditions is robust for a variety of vehicle-vehicle and vehicle-infrastructure safety applicationsvehicle-infrastructure safety applications

Some degree of packet loss, as expectedSome degree of packet loss, as expected Multipath transmissionsMultipath transmissions Vehicle obstructing LoSVehicle obstructing LoS

Range, update rate, and latency requirements for the Range, update rate, and latency requirements for the Task 3 safety applications should be feasibleTask 3 safety applications should be feasible

Areas for future study include:Areas for future study include: Transmission power variationTransmission power variation Multi-sender, multi-receiver scenariosMulti-sender, multi-receiver scenarios

Vehicle Safety Communications Project VSC Progress Briefing #2 – Task 4 Field Testing –

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