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

1. Vehicle Safety Communications Project VSC Progress Briefing #2 – Task 4 Field Testing – Overview of Hardware and Software Test Track Results

2. Outline Overview 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

3. Test Equipment • VSC Communication Test Kits (CTKs) • Laptops with 802.11a card • DGPS receivers • Magmount DSRC and DGPS antennas • Portable implementation

4. CTK Configuration

5. CTK Sender Interface • Broadcast duration • Update rate • Packet size

6. CTK Receiver Interface • Packet number • OS/GPS timestamp • DGPS location coordinates

7. Outline Overview 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

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

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

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

11. Effect of GPS satellite obstruction

12. Outline Overview 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

13. Test Track Facilities Test Track • Controlled environment • Two-lane test road • Straight-away with rural surroundings • Overhead bridge can disrupt GPS signal Overhead Bridge

14. Outline Overview 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 v v 1 2 d x1 d y1 x z y Two Static Antennas Legend: Sender Receiver

15. v1 v2 dx1 x dy1 z y Two Static Antennas • 200m range, 200 bytes, ~100 msec update rate • Direct Line of Sight (LoS), no packet loss

16. Two Static Antennas • Obstructed LoS (stationary SUVs) • No packet loss at various distances

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

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

19. Outline Overview 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 d x1 v (RSU) 2 f f d y1 x z y One Dynamic Antenna (OBU)One Static Antenna (RSU) 1 Legend: Sender Receiver Obstructer

20. dx1 v1 f x dy1 z y One Dynamic, One Static Antenna • Receiving vehicle ~60 mph • No packet loss

21. dx1 (RSU) v2 dy1 x z y One Dynamic, One Static Antenna • Transmitting vehicle ~60 mph • A few lost packets

22. dx1 (RSU) v2 dy1 x z y One Dynamic, One Static Antenna • Transmitting vehicle ~20 mph • A few lost packets

23. dy1 v1 f dx1 One Dynamic, One Static Antenna • Receiving vehicle ~40 mph, with obstruction • No packet loss

24. One Dynamic, One Static Antenna • Transmitting vehicle ~40 mph, with obstruction • No packet loss

25. Outline Overview of Hardware and Software • Test Equipment and Interface • Format of Data/Findings Test Track Testing • Test Track Facilities • Dynamic Results • Multipath Considerations • Static Results • Conclusions Two Dynamic Antennas (OBUs) 1 Legend: Sender Receiver Obstructer

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

27. Two Dynamic Antennas • Various speeds, same direction, ~150 m range • Cut-in SUV, no packet loss

28. Two Dynamic Antennas • Sender vehicle and SUV brake to a stop • Lost packets are likely due to SUV obstruction

29. Two Dynamic Antennas • Receiver passes sender braking from 30 – 0 mph • Packet loss at ~ 90 m

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

31. Two Dynamic Antennas • Sender and receiver pass at 30 mph • Packet loss at ~ 90 m

32. Outline Overview 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

33. Multipath Considerations • Two-Ray Ground Multipath Model • Etotal = ED+ ER(ej) • Emin = ED– ER when  = π D: Direct Line of Sight R: Reflected Line of Sight

34. Multipath Considerations • Null spot found through slow-rolling test • Loss of packets between ~ 87 m and 94 m West overpass LeSabre - receiver driving on the shoulder towards SUV. Facing East. SUV – sender stopped. Facing west Track entrance

35. Multipath Considerations • Steady state test at ~ 92 m null spot • Almost complete loss of packets

36. Test Track Conclusions • Single-sender, single-receiver DSRC under direct LoS conditions is robust for a variety of vehicle-vehicle and vehicle-infrastructure safety applications • Some degree of packet loss, as expected • Multipath transmissions • Vehicle obstructing LoS • Range, update rate, and latency requirements for the Task 3 safety applications should be feasible • Areas for future study include: • Transmission power variation • Multi-sender, multi-receiver scenarios