Quality of Service in a GSM-R PPP

Quality of Service in a GSM-R PPP
Jean CELLMER
UIC ERTMS 2014
The RFF GSM-R project
Preliminary study started in 2000
Start of rollout in 2003 with the first supply contract given to Nortel
GSM-R scenario:
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Replacement of analog system : 14,000 km on a total of 32,000 km
Unique train radio for new lines : East European High Speed Line first
10 year rollout
Radio optimized for 8 Watt cab radios
Planned number of users: 10,000 cab radios + 30,000 handhelds
ETCS level 2 on high speed lines
Architecture:
 1 Core Network active (+ 1 back up site)
 17 Base Station Controllers,
 2,500 Base Stations (radio sites)
The RFF GSM-R network architecture
2 MSCs (1 +1)
17 BSCs
2500 BTSs
and:
- A test platform including a test line
- A national supervision centre
Dunkerque
Calais
Hazebrouck
Lille
Boulogne
Tourcoing
Baisieux
Bethune
Lens
Rue
Valenciennes
Douai
Jeumont
Aulnoye
Arras
Cambrai
Abbeville
Busigny
Amiens
Hirson
Clères
Le Havre
Charleville M.
Liart
Tergnier
Longwy
Apach
Laon
Beauvais
Longuyon
Creil
Rouen
Longueil
Ormoy
Persan
Mantes
Brest
Dreux
St Brieuc
Chartres
Sablé
Auray
Vannes
Bening
Kehl
Vittel
Troyes
Chaumont
Colmar
Merrey
Courtalain
Neuenbourg
Connerré
Mulhouse
Laroche M.
Redon
Orléans
Culmont Ch.
Les Laumes
Blois
Angers
Bâle
Belfort
Tours
Le Croisic
Strasbourg
Molsheim
Longueville
Etampes
Le Mans
Forbach
Metz
Conflans J
La Ferté B
Laval
Rennes
Quimper
Reims
Rémilly
Chalons
Pagny
Chateau Epernay
Bar le Duc
Thierry
Blesmes
Lérouville
Coulommiers
Reding
St Dizier
Provins
Tournan
Vitry le F.
Toul
Nancy
Paris
Plaisir G.
Guingamp
Thionville
Dijon
Saumur
Franois
Vierzon
Nantes
Clerval
Besançon
Bourges
Dôle
Nevers
Thouars
St Florent
Chatellerault
Arc et Senan
Chagny
Saincaize
Mouchard
Chateauroux
Poitiers
Moulins
Genève
St Amour
Bourg
Mâcon
St Germain des F.
Gannat
Roanne
Ruffec
Riom
Limoges
Angoulème
Clermont -F.
Annecy
Culoz
Ambérieu
Lyon
Givors
Nexon
Aix
St André le G.
Chasse
Albertville
Bourg St Maurice
Chambery
St Etienne
Arvan
Brive
Romans
Libourne
Bordeaux
Gourdon
Grenoble
Modane
Valence
Cahors
Arcachon
Agen
Orange
Morcenx
Montauban
Nîmes
Tarascon
Dax
Montpellier
Toulouse
Bayonne
Hendaye
Vintimille
Avignon
Puyoo
Cannes
Arles
Miramas
Aix
Béziers
Sète
Tarbes
Marseille
Montréjeau
Carcassonne
Narbonne
Perpignan
Port Bou
Toulon
Why a PPP?
June 2004: a new French Law authorising PPP (Public Private Partnership)
Why a GSM-R PPP?
 Rollout time schedule could be reduced
 RFF and SNCF could benefit from additional competencies in term of rollout
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and network operation thanks to mobile operators involvement
RFF financial risks would be limited since the price is definitely fixed in the
Partnership contract
Operation costs could be reduced thanks to mutualisation of activities and
resources (a common network operating centre)
Additional revenues allocated to the private partner, reducing the price paid
by RFF
RFF CAPEX postponed and partly changed in OPEX.
The main aspects of the French PPP contract
A 15 year contract signed in March, 2010 with a new company named
SYNERAIL
Complete rollout of the GSM-R network
Operation of the complete GSM-R network, including the part which was
built by RFF (transfered to SYNERAIL in March, 2011)
Maintenance, upgrade, replacement of all necessary hardware and
software equipment until 2025
New services on the network in order to improve business revenue
Future High Speed Lines: connection to the GSM-R national network and
support of local GSM-R Base Station Subsystem (the radio sites)
A very high grade of service:
 Train to ground radio, 100% compliant to EIRENE specification
 ETCS level 2 data transmission on High Speed Lines
What’s not in the PPP
Transmission links between network elements are still supplied by
RFF.
These fiber optic or copper cables already exist and are used for
various telecommunication applications. They could not be
dedicated to GSM-R and transfered to the GSM-R PPP.
This share of responsibilities create some difficulties and needs a
good organisation.
Fixed telephony is also supplied by RFF. The Private Partner is just
responsible for integration of these equipment in the end to end
system.
GSM-R PPP: Area of responsibility of SYNERAIL
NSS
BSS
Base Station Subsystem
Network Switching
Subsystem
SYNERAIL domain
Cab radios
FTS: SNCF
(Primary and secundary controllers)
BSC
Handhelds
BTS
(Base Transceiver
Station)
Lineside
Telephone
Sets
(Base Station
Controller)
SDH Transmission: SNCF
BSC
(7 sites)
BTS
Local loop: copper cables and fiber optics: SNCF
7
A complex contractual organisation
Rollout
independant
Controler
RFF
Specific contractual
relationship
PPP contract
Certification of
sites
Stakeholders
contract
Stakeholders
SYNERAIL
Building contract
Financing contract
Banks
Operation and maintenance contract
Interface contract
Temporary building consortium : SYNERAIL
CONSTRUCTION
Sub contract
Sub
contractor N
Sub contract
Sub
contractor
N+1
Sub contract
Small
companies
Consortium for operation and maintenance :
SYNERAIL EXPLOITATION MAINTENANCE
Sub contract
Sub
contractor N
Sub contract
Small
companies
Lessons learnt from RFF experience
A very complex organisation
Managing a PPP contract is all but simple: Financial, operational,
technical aspects have to be dealt with by numerous
contractors.
Too many interfaces
RFF is the customer but RFF is also the supplier of transmission
links, works along the track safety etc.
Lessons learnt from RFF experience
The temptation to over specify
In a PPP contract the private partner is responsible for the network
design and RFF should have only issued functional specifications,
mainly expressing RFF’s needs in term of services, QoS, maps of lines
to be covered, railway constraints.
But RFF explained very precisely its internal rules: no candidate took the
risk of not following RFF’s rules and no one showed creativity.
SYNERAIL designs and builds the same network as RFF did.
Quality of Service in a GSM-R PPP network
There is a contractual relationship between RFF and the private
partner. SYNERAIL is committed to:
 Guarantee a permanent GSM-R service (train radio and support for
ETCS level 2)
 Instantly inform RFF in case of any loss of service
 Keep the network as new until the contract end (2025)
 Pay penalties for every break in the contractual rules
RFF is permanently informed of the network status
SYNERAIL Exploitation comes from a mobile operator (SFR):
 Technicians are very professional, well skilled and trained
 There is an efficient human resource sharing with SFR
 But sometimes, there is a need to better understand the railway
specific environment and constraints
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/ UIC/PTA 23 May 2011
The network Operation Centre is shared with a mobile
operator’s
SFR operation centre: one table is dedicated to GSM-R
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QoS: Level of performance
SYNERAIL is committed to deliver the GSM-R service with a contractual
level of performance:
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Radio coverage: minima signal level > - 98 dBm pour train radio and
> -92 dBm for ETCS level 2
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Handover on Power Budget: > 90%
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Handover ping pong: < 1%
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Voice quality: MOS > 3 and RXQUAL < 2 (*)
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Call drop rate for voice < 1.5%
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Call drop rate for ETCS < 1 call drop per 100 hours
Etc.
(*) RXQUAL is a GSM-R parameter which qualifies the received signal quality
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Quality of Service: Service availability
Three categories of sites
 Normal sites: Conventional lines
 Critical sites: High Speed Lines + around 100 sites on conventional lines
 ETCS level 2 sites
For every radio site a maximum downtime per year is specified:
 99.51% availability of service for conventional (40 hours cumulative max outage)
 99.91% availability of service for critical (8 hours cumulative max outage)
 99.99% availability of service for ETCS level 2 (52 mns cumulative max outage)
In addition Time To Repair (TTR) per site is limited to 4 hours
 Every service affecting breakdown must not last more than 4 hours
QoS: Information of RFF and SNCF
In case of a service breakdown:
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SYNERAIL must inform SNCF railway operator in less than 5
minutes of any issue which could have a negative effect on railway
traffic
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They must confirm in less than 20 minutes that the issue is not fixed
and explain the consequences in term of affected area, likely
duration of the problem, possible reason for this issue to go on etc.
After service recovery:
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SYNERAIL must inform SNCF in less than 5 minutes
In case of a Railway Emergency Call:
 SYNERAIL must provide, on request of SNCF, a provisional technical
information in less than 15 minutes (call trace) and complete
information in 24 hours,
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Some railway specific issues
In spite of their professional experience, SYNERAIL technicians are
facing some new issues:
•
No alarm out-of-service sites:
• A Public GSM site is monitored by counters of traffic
• A GSM-R site (non ETCS) is not used to support permanent traffic
• In case of loss of service without alarm notification (i.e. antenna) train
drivers are the only source of information: no way to fix the issue in less
than 4 hours!
•
Very high requested availability:
• A public network can live with several sites out-of-service for hours/days
especially far from peak hours
• A GSM-R network needs to be permanently in service, all sites (no
coverage overlap), especially ETCS sites
•
A strong need to inform railway operators in case of a breakdown
and after service recovery:
• Some outages could lead to a railway traffic stop.
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Conclusion
Operating a GSM-R network in a PPP mode is a good way to improve
the Quality of Service thanks to the presence of mobile operators
skilled and well trained people.
But these professionals often need a time to fully understand railway
constraints and specificity.
Questions?
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/ UIC/PTA 23 May 2011

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