World Class Standards Coexistence plugtest: CEN DSRC CEN DSRC / ITS-G5 coexistence RTTT / CEN DSRC...

World Class Standards

Coexistence plugtest: CEN DSRC

CEN DSRC / ITS-G5 coexistence

RTTT / CEN DSRC

Coexistence plugtest

Ispra, Italy

4 July 2011Anders Hjelmare

© ETSI 2011. All rights reserved


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Electronic Fee Collection, EFC Electronic Toll Collection, ETC road tolls road user charges …


using RTTT CEN DSRC 5,8 GHz CEN TC278 ...


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In many countries



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European history of RTTT / CEN DSRCStandardisation

Deployment

1990 2000 2010

1987 Worlds first ETC system in Aalesund, Norway

1991 Start of DSRC standardisation in CEN, Vienna agreement between CEN and ETSI

Deployment of proprietary DSRC systems

1997 – First versions of the CEN DSRC standards

Start deployment of systems based on CEN standard and closing down proprietary systems

2004 – Updated versions

CEN standard systems currently deployed in 13 European Countries

Complete set of ETSI test standards



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Relevant documents

ERC Report 3: Frequency bands for RTTT ERC Recommendation T/R 22-04 ERC Recommendation 70-03, Annex 5 ERC Decision (92)02: Frequency bands for RTTT ECC Decision (02)01: Frequency bands for RTTT EN 12253 RTTT DSRC Physical layer EN 12795 RTTT DSRC Data Link Layer EN 12834 RTTT DSRC Application Layer EN 13372 RTTT DSRC Profiles EN 300 674 RTTT DSRC in 5,8 GHz ISM band



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A small part of the radio frequency spectrum


5000 MHz 6000 MHz

5800 MHz 5900 MHz

RTTT ITS G5

5850 MHz 5850 MHz


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EFC station side viewRoad Side Unit, RSU

On Board Unit, OBU

Downlink

Uplink


Half duplex

Backscatter

RSU = masterOBU = slave


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RTTT power levels (approx)

OBU is semi-passive!

RSU transmit power +33 dBm 2 W

Downlink attenuation - 70 dB

OBU incident power - 47 dBm 20 nW

OBU transmit power - 38 dBm 160 nW

Uplink attenuation - 70 dB

RSU incident power - 108 dBm 0,015 nW



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OBU wake-up

Specified in EN 12253

Sensitivity - 43 dBm or better

On any RTTT frame


No specification for wake-up immunity

Vendor specific implementation and properties


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EFC, initialization


VST Vehicle Service Table

OBU

Beacon Service Table

RSU

BST

BST

BST

BST

BST

BST


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EFC, transaction (example)


Read data

RSU OBUGET.rq

GET.rs

SET.rq

SET.rs Write data

ACTION.rqRelease


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EFC, frame timing (example)


Downlink = RSU modulatedUplink = RSU carrier only (OBU modulates carrier)

0 1 2 3 4 5 6

Downlink Uplink Uplink Uplink DownlinkBST Public Uplink

Downlink Uplink DownlinkGET.rq Private Uplink

ms


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EFC, transaction timing

• In high speed stations, RSU ‘thinking’ time is minimized (≈ 1 - 2 ms)

Downlink Uplink Downlink Uplink Downlink Uplink Downlink Uplink Downlink Uplink

• In free flow stations, exact transmission scheme is station specific


Downlink Uplink Downlink Uplink

• In low speed stations, RSU ‘thinking’ time may be long (10 - 100 ms ?)


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EFC, retransmission

• Exact retransmission scheme is station specific


• If no uplink is received, RSU normally retransmits

Frame 12 Frame 12 Uplink Frame 13 Frame 13 Uplink Frame 14 Uplink


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EFC, transaction duration


100%

0 10 20 30 40 50 60 70 80 90 100 110

50%

ms

Time available, good case

Time available, worst case?


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EFC, transaction duration (2)


Transaction times are statistically distributed

Longer transaction times > more transaction failures

Road operators: <0,5% … <0,1% … 0%

Max Transaction Error Ratio?


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End Comments and Inputs

Thank you for your attention!

Anders HjelmareKapsch TrafficCom AB


World Class Standards Coexistence plugtest: CEN DSRC CEN DSRC / ITS-G5 coexistence RTTT / CEN DSRC...

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