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Developing the Future Radio for Rail TransportETSI Workshop4-5 July 2018

Gautier BRODEO UITP

Urban Rail Expert

URBAN RAIL EXPECTATIONS FOR FUTURE COMMUNICATION SYSTEMS

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CONTEXTURBAN RAIL RADIOURBAN SPECIFIC CONSTRAINTSSTRATEGY FOR CBTCCONCLUSION

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CONTEXT1

URBAN RAIL EXPECTATIONS FOR FUTURE COMMUNICATION SYSTEMS

1 - CONTEXT

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Urban Challenge for future

2/3 of the world’s population will be living in cities by 2050Optimizing the modal shift in a context of:

Mobility growth (+ 25% of metro usage in France on past 15 years)Saturation of urban traffic networks Environmental challenge:

Control of local pollutant emissionsDepletion of fossil fuels

1 - CONTEXT

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Capacity by mode of transport in urban environmentOn a public space of 3m50 it is possible to carry up to:

1 000 pax/h/direction by car

6 700 pax/h/direction by tramway

x 6,760 000 pax/h/direction

by subway

X 60

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URBAN RAIL RADIO

URBAN RAIL EXPECTATIONS FOR FUTURE COMMUNICATION SYSTEMS

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2. URBAN RAIL RADIO

Urban Rail mostcommon situation

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3 separated functions most often using 3 different radios

TETRA Radio (Eu TETRA band 410-430 MHz)

Voice trunkingDiscrete listeningLive public address

Radio TDST (WiFi ISM bands 2,4 and/or 5,8 GHz)

CCTVPre-recorded PAPassengers information / entertainmentMaintenance data

CBTC Radio (derived fromWiFi on ISM band 2,4 GHz or dedicated band 5,9 GHz)

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2. URBAN RAIL RADIO

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Communications performances cartography

Signalling (CBTC)

Voice

Video & PassengerInformation

Maintenance Data

AVAILABILITYLow High

High

SAFE

TY

Data volume

2. URBAN RAIL RADIO

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CBTC principle, with use of radio transmissions

Radio transmission criteria for CBTC are: vital & symmetric flows, high reliability, high priority, low-medium latency, low throughput (per train), full coverage.

Vital On-board Unit

Safety limit fixed by the vital zone computing unitVital speed profile computed

by the vital on-board unit

Vital On-board Unit

Vital Zone Computing Unit Interlocking

Sends Movement Authority Limit to trains

Transmits train positionTransmits train position

Radiofrequency real-time & bidirectional

communication

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URBAN SPECIFIC CONSTRAINTS

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URBAN RAIL EXPECTATIONS FOR FUTURE COMMUNICATION SYSTEMS

3 – URBAN SPECIFIC CONSTRAINTS

Real-time performance30-240 seconds dynamic headway (gap between trains)Depends on:

Train traction & braking characteristics (Rolling Stock issue)Vital computers calculation time cycles (CBTC issue)Radio communication performance (Communication system issue)

SafetyIntegrity of data related to environmental conditions andlocalizationService availability (avoid passengers evacuation if possible)

SecurityFulfill EN 50159 (Closed communication network)National cybersecurity requirements (Vital Important System)

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Impacts on communication architecture #1/2

High level of availabilityWay side and on board radio redundancyAvailability of the air gap: rather dedicated than openfrequency band

Life spanRelated to frequency band allocation and technologyTo be compliant with CBTC system : 30/40 years

Quality of serviceOperation in tunnels (obstruction from other trains)or urban dense areas (electromagnetic interferences)

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Impacts on communication architecture #2/2

3 – URBAN SPECIFIC CONSTRAINTS

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STRATEGY FOR CBTC

URBAN RAIL EXPECTATIONS FOR FUTURE COMMUNICATION SYSTEMS

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4 - STRATEGY FOR CBTC

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Which technology for CBTC radio transmission?

Converge with main rail technologies (FRMCS)?Constraints are differentNGTC project results: only 100/800 functions can be mergedFurther studies needed

Converge with Road-ITS technologies (ETSI-G5, CV2X)?Contraints are different, needs further investigationsOngoing studies in ETSI

Migrate to 4G or 5G?China and Australia migrate CBTC to LTE why not Europe?

4 - STRATEGY FOR CBTC

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Which technology? Focus on LTE solutionLTE would adress urban rail technical needs

Originally developed to support 4G and 5G (IoT) network: new services!

Technical possible: Same IP base interface

Allow to put together all transmission services

LTE can offer dedicated QoS agreements (permanent monitoring for dynamic adaptation between services)

LTE will implement VPN for cybersecurity

LTE infrastructure is coming cheaper and cheaper and much simpler (each new release of LTE is « OPEX saving »… )

For green-field projects, the time delay between infrastructure deployment and revenue service for telecom operators is far too long… better for urban rail to own its infrastructure

4 - STRATEGY FOR CBTC

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Which technology? Focus on LTE solution

A model still to be adressed:

Private infrastructure only possible with dedicated bandwidth Availability of the 5,9GHz band?

Third-party operated? Or proprietary infrastructure? With which lifespan?

Multimodal infrastructure? Or a dedicated network per mode or per line?

What life cycle consideration (maintenance, evolution of needs: video,migration, cybersecurity, etc…)?

Which OPEX figures?

4 - STRATEGY FOR CBTC

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Which frequency band for CBTC radio transmission

1 - Back to open ISM bands (2,4 or 5,8 GHz)Bad experience (Paris, Singapore, China,…)

need to identify new technologies/countermeasures allowing togrant systems availability (ex: radiating cables, frequency hoping,spread spectrum,…)

Not recommended

2 – Dedicated and protected Urban Rail frequency Band(Chinese government):

Allow every technologiesThe 5,9 GHz band: the best candidate in Europe

Continuity of operational CBTCNeed to share spectrum with Road-ITSOn going discussions at ECC and CEPT levels through dedicated WGs

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CONCLUSION5

URBAN RAIL EXPECTATIONS FOR FUTURE COMMUNICATION SYSTEMS

5 - CONCLUSION

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CBTC 2.0 ?

New technologies are emerging regularly: 4G, RoadITS, 5G …

But life spans are not in tune with Urban Rail systems!

Whatever the technology, it is essential to benefit froma dedicated band to protect all CBCT systems, which isperennial!

Need to protect the 5.9 GHz band for Urban Rail