Establishing Radio Links at 60 GHz for Truck Platooning

Presentation by,Manigandan Sivasubramanian.

Supervised by,Dr. Ir. Peter Smulders. ( Internal )Ir. Jacco Van de Sluis. ( External - TNO)

OVERVIEW OF THE PRESENTATION :

Introduction

Motivation and Objective

Truck Platooning and ITS–G5

IEEE 802.11ad

Propagation Mechanisms

Experiments at 60 GHz

LOS and NLOS Measurements

Special Cases

Future works and Conclusion

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INTRODUCTION

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OBJECTIVE

“Communication plays one of the key role in truck platooning and this project aims to make it more reliable by testing IEEE 802.11ad as the secondary redundant radio link”.

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INTRODUCTION TO THE PROJECT

• TNO is an independent research company constantly looking

for new solutions.

• To complement their existing communication link for truck

platooning.

• For this purpose, IEEE 802.11ad is tested in this project.

• This will guarantee a safe and reliable communication.

• Channel propagation characteristics , large scale shadowing

effects are studied.

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TRUCK PLATOONING

• Truck platooning comprises of trucks equipped with state of art driving support

system following each other.

• CACC and/or ACC are technologies behind truck platooning.

• Platooning improves the traffic safety with zero reaction time.

• Lower fuel consumption and less Cemission.

• Communication between trucks is essential and ITS-G5 is used.

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VEHICULAR COMMUNICATION (DSRC) – ITS-G5

• ITS-G5 is European standard and use IEEE 802.11p amendment.

• It is for data-only systems and operate on radio frequencies in the 5.725 – 5.875 MHz

• Broadcasting feature and support for Cooperative ITS.• It support single hop and multi hop transmission.

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IEEE 802.11ad

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S.No Parameter Value1 Operating Frequency 60 GHz

2 Number of Channels 4 (each 2.16 GHz wide)

3 Channel Frequency 58.32 , 60.48 , 62.64, 64.80 GHz.

FEATURES OF IEEE 802.11ad

• Huge Bandwidth availability.

• Standard specifies a “fast session transfer” feature, enabling wireless devices to

seamlessly transition between 60 GHz and the legacy 2.4 GHz and 5 GHz bands.

• Support for MIMO , it defines a new directional communication scheme to cope

with increased attenuation called “Virtual” antenna sectors that discretize

antenna azimuth.

• MAC algorithms include TDMA, CSMA/CA and polling. Applications requiring

gigabits data rate will benefit.

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Fig : Nodes communicating overVirtual Antenna Sector

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RADIO WAVE PROPAGATION AND CHANNEL MODEL

• Reflection , Diffraction and Scattering mechanisms – they depend on

size of the object and propagation path.

• FREE – SPACE MODEL: (Assumes ideal propagation condition)

* *(

It obeys distance power law which is given by,

PL (d) = PL (do) + 10 n log (d/ do) (1)

Path Loss exponent is a measure of decay in signal power with distance

• TWO – RAY MODEL: (Oscillation in power level by constructive and

destructive combination)

• Models at UHF for decay of power , depends on environment and breakpoint distances.

• Beyond breakpoint distance , measured and free-space value do not agree.

• Multipath Channel Characteristics – path loss exponent and delay spread describes the

property of a channel. LOG-DISTANCE PATH LOSS MODEL :

• Fading : Another significant part of wireless communication design. Small scale fading

and large scale shadowing are two types.

• The effect of shadowing can be included in the distance power law (1) as

• Value of n and are derived by linearly fitting measured path loss over log-distance.

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RECEIVED POWER AND CHANNEL MODEL

PL (d) = PL (do) + 10 n log (d/ do) + X

CHANNEL MEASUREMENTS AND ANALYSIS

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Description of Environment and Measurements

• Storage Area• Parking lot

Devices and Antennas Used:

• Vubic PEM – 009 Transceivers• Agilent 60 GHz Received Power Sensor and Power Meter• Fan – beam Antenna with 16.5 dbiGain. • Pencil beam Antenna with 34 dbigain

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STORAGE AREA : FLOORPLAN AND RESULT

Environment Characteristics :

n = 2.3 ; σ = 2.4 ; L (do) [dB] = 36.0

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PARKING LOT: FLOORPLAN AND RESULT

Environment Characteristics :

n = 1.5 ; σ = 4.2 ; L (do) [dB] = 36.0

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NLOS MEASUREMENTS

Fig : Obstruction by Truck Scenario

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RECEIVED POWER – NLOS MEASUREMENTS

• The difference in power level between LOS and NLOS is only 13 dB.

• LOS with obstruction vehicle has less difference in their power level with LOSprobably because of asphalt road surface.

• Reflection of signals from road surface helps in signal propagation – this leads toexploration on alternative antenna placements.

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RECEIVED POWER – LOS WITH DIFFERENCE IN ANTENNA HEIGHTS

Fig : Illustration of Two-Ray Model

• This experiment shows effect of Tx and Rx antenna heights on propagation losses.

• ht = 1.10 meters , hr = 0.90 meters. Two Ray Model requires less interference.

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RECEIVED POWER – MEASURED AT A FIXED DISTANCE IN VARIOUS ANTENNA ANGLE

APPLICATION : TRANSMISSION OF I/Q SIGNALS

I/Q modulation is an efficient way to transfer information. Hence we made use of random binary digits as input and transmitted it by generating I/Q signals.

Equipment and software used :

• 60 GHz transceivers• Antennas Used : Fan-beam Antennas with 16.5 dB gain.• Rohde and Schwarz AMIQ (I/Q Signal generator)• Rohde and Schwarz SMIQ ( Carrier Signal Generator)• Rohde and Schwarz FSIQ (Signal Analyzer)

Environment: Experiments are conducted in the propagation and system integration lab of CWT/e Lab at TU/e.

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BLOCK DIAGRAM

• Trial 1: QPSK signal

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Symbol Rate: 4.096 MHzFilter: Root Cosine with roll off factor: 0.5Data Source: PRBS.Coding : None.

Transmission frequency: 58.32 GHz.Carrier Signal Generated at Rx : 500 MHz.Received Channel Power: -22 dBm.Received Signal to Noise Ratio : 5.47 dB.

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FUTURE WORKS AND

CONCLUSION

FUTURE WORKS

• Demonstration of High-definition video transmission at 60 GHz.

• Planning of experiments on the truck requires making the measurement

setup more user friendly thus enabling reproducible measurements.

• Experiments to test slow and fast fading effects .

• How asphalt road surface can be used for signal propagation if

the environment doesn’t have metallic objects.

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CONCLUSION AND SUMMARY

• Practical experiments show that the presence of

metallic objects in the environment help in signal

propagation.

• Path Loss Exponent between 2-3 implies that 60 GHz

signal propagation is not much affected by multipath .

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Environment L (do) [dB] n

Parking lot – LOS 36.0 1.5 4.2

Storage Area – LOS 36.0 2.3 2.4

Storage Area - NLOS 34.2 2.5 9.2

• Two-ray model shows that an apparent minor difference

in the model can make significant change in behavior of

radio propagation.

• The performance of communication even at NLOS path

differs only by 13 dB because of reflection.

• Asphalt road surface helps in reflection of signals even

when the LOS between transceivers are blocked, thus this

allow for exploration on alternative antenna placements.

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THANK YOU QUESTIONS ?

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APPENDIX : DSRC – TECHNICAL OVERVIEW (Features of ITS-g5)

CHALLENGES : Congestion Control Bandwidth Availability

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S.NO Parameters Value

1 Frequency Range 5.855 – 5.925 MHz

2 Channels Available 7 with 10 MHz each

3 Modulation BPSK, OFDM, QPSK, 256-QAM…

4 Data Rate 6,9,12,18,24 and 27 Mbps

5 Power Less than 2W (33dBm)*

6 Message Types CAM , DENM.

* - Can go up to 30 W (44.8dBm) for public safety applications on Control Channel

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APPENDIX : INTRODUCTION OF VEHICLE IN THE LOS :

This test was done to see howcommunication was affected when a vehicle is introduced in the propagation path.

• Truck platooning is a modern application aiming to provide safer and cleaner transportation.

• ITS G-5 is the envisioned communication protocol used for this purpose but has limited

bandwidth.

• IEEE 802.11ad is proposed to complement this existing link with additional link capacity.

• Theoretical study on various challenges that comes with IEEE 802.11ad have been studied.

Estimating Path Loss Exponent and Zero-mean Gaussian distributed random variable with

standard deviation Sigma.

- - - > (1)

Then sum of squared errors between measured and estimated values is given by

- - - > (2) ; J(n) = 0

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• Free-pace path loss :

FSPL =